mirror of
https://github.com/systemd/systemd
synced 2025-10-06 00:13:24 +02:00
00a415fc8f
Let's bump the kernel baseline a bit to 4.3 and thus require ambient caps. This allows us to remove support for a variety of special casing, most importantly the ExecStart=!! hack.
5687 lines
233 KiB
C
5687 lines
233 KiB
C
/* SPDX-License-Identifier: LGPL-2.1-or-later */
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#include <linux/sched.h>
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#include <sys/eventfd.h>
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#include <sys/ioctl.h>
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#include <sys/mount.h>
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#include <sys/prctl.h>
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#if HAVE_PAM
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#include <security/pam_appl.h>
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#include <security/pam_misc.h>
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#endif
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#if HAVE_APPARMOR
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#include <sys/apparmor.h>
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#endif
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#include "sd-messages.h"
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#if HAVE_APPARMOR
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#include "apparmor-util.h"
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#endif
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#include "argv-util.h"
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#include "barrier.h"
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#include "bpf-dlopen.h"
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#include "bpf-restrict-fs.h"
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#include "btrfs-util.h"
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#include "capability-util.h"
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#include "cgroup-setup.h"
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#include "chase.h"
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#include "chattr-util.h"
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#include "chown-recursive.h"
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#include "copy.h"
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#include "data-fd-util.h"
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#include "env-util.h"
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#include "escape.h"
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#include "exec-credential.h"
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#include "exec-invoke.h"
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#include "execute.h"
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#include "exit-status.h"
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#include "fd-util.h"
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#include "hexdecoct.h"
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#include "hostname-setup.h"
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#include "io-util.h"
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#include "iovec-util.h"
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#include "journal-send.h"
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#include "missing_ioprio.h"
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#include "missing_prctl.h"
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#include "missing_sched.h"
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#include "missing_securebits.h"
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#include "missing_syscall.h"
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#include "mkdir-label.h"
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#include "proc-cmdline.h"
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#include "process-util.h"
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#include "psi-util.h"
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#include "rlimit-util.h"
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#include "seccomp-util.h"
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#include "selinux-util.h"
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#include "signal-util.h"
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#include "smack-util.h"
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#include "socket-util.h"
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#include "string-table.h"
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#include "strv.h"
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#include "terminal-util.h"
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#include "utmp-wtmp.h"
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#include "vpick.h"
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#define IDLE_TIMEOUT_USEC (5*USEC_PER_SEC)
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#define IDLE_TIMEOUT2_USEC (1*USEC_PER_SEC)
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#define SNDBUF_SIZE (8*1024*1024)
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static int flag_fds(
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const int fds[],
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size_t n_socket_fds,
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size_t n_fds,
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bool nonblock) {
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int r;
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assert(fds || n_fds == 0);
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/* Drops/Sets O_NONBLOCK and FD_CLOEXEC from the file flags.
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* O_NONBLOCK only applies to socket activation though. */
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for (size_t i = 0; i < n_fds; i++) {
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if (i < n_socket_fds) {
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r = fd_nonblock(fds[i], nonblock);
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if (r < 0)
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return r;
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}
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/* We unconditionally drop FD_CLOEXEC from the fds,
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* since after all we want to pass these fds to our
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* children */
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r = fd_cloexec(fds[i], false);
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if (r < 0)
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return r;
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}
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return 0;
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}
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static bool is_terminal_input(ExecInput i) {
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return IN_SET(i,
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EXEC_INPUT_TTY,
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EXEC_INPUT_TTY_FORCE,
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EXEC_INPUT_TTY_FAIL);
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}
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static bool is_terminal_output(ExecOutput o) {
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return IN_SET(o,
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EXEC_OUTPUT_TTY,
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EXEC_OUTPUT_KMSG_AND_CONSOLE,
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EXEC_OUTPUT_JOURNAL_AND_CONSOLE);
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}
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static bool is_kmsg_output(ExecOutput o) {
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return IN_SET(o,
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EXEC_OUTPUT_KMSG,
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EXEC_OUTPUT_KMSG_AND_CONSOLE);
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}
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static bool exec_context_needs_term(const ExecContext *c) {
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assert(c);
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/* Return true if the execution context suggests we should set $TERM to something useful. */
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if (is_terminal_input(c->std_input))
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return true;
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if (is_terminal_output(c->std_output))
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return true;
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if (is_terminal_output(c->std_error))
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return true;
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return !!c->tty_path;
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}
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static int open_null_as(int flags, int nfd) {
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int fd;
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assert(nfd >= 0);
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fd = open("/dev/null", flags|O_NOCTTY);
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if (fd < 0)
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return -errno;
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return move_fd(fd, nfd, false);
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}
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static int connect_journal_socket(
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int fd,
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const char *log_namespace,
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uid_t uid,
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gid_t gid) {
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uid_t olduid = UID_INVALID;
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gid_t oldgid = GID_INVALID;
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const char *j;
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int r;
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assert(fd >= 0);
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j = journal_stream_path(log_namespace);
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if (!j)
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return -EINVAL;
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if (gid_is_valid(gid)) {
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oldgid = getgid();
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if (setegid(gid) < 0)
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return -errno;
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}
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if (uid_is_valid(uid)) {
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olduid = getuid();
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if (seteuid(uid) < 0) {
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r = -errno;
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goto restore_gid;
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}
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}
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r = connect_unix_path(fd, AT_FDCWD, j);
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/* If we fail to restore the uid or gid, things will likely fail later on. This should only happen if
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an LSM interferes. */
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if (uid_is_valid(uid))
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(void) seteuid(olduid);
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restore_gid:
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if (gid_is_valid(gid))
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(void) setegid(oldgid);
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return r;
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}
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static int connect_logger_as(
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const ExecContext *context,
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const ExecParameters *params,
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ExecOutput output,
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const char *ident,
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int nfd,
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uid_t uid,
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gid_t gid) {
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_cleanup_close_ int fd = -EBADF;
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int r;
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assert(context);
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assert(params);
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assert(output < _EXEC_OUTPUT_MAX);
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assert(ident);
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assert(nfd >= 0);
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fd = socket(AF_UNIX, SOCK_STREAM, 0);
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if (fd < 0)
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return -errno;
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r = connect_journal_socket(fd, context->log_namespace, uid, gid);
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if (r < 0)
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return r;
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if (shutdown(fd, SHUT_RD) < 0)
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return -errno;
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(void) fd_inc_sndbuf(fd, SNDBUF_SIZE);
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if (dprintf(fd,
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"%s\n"
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"%s\n"
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"%i\n"
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"%i\n"
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"%i\n"
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"%i\n"
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"%i\n",
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context->syslog_identifier ?: ident,
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params->flags & EXEC_PASS_LOG_UNIT ? params->unit_id : "",
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context->syslog_priority,
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!!context->syslog_level_prefix,
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false,
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is_kmsg_output(output),
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is_terminal_output(output)) < 0)
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return -errno;
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return move_fd(TAKE_FD(fd), nfd, false);
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}
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static int open_terminal_as(const char *path, int flags, int nfd) {
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int fd;
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assert(path);
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assert(nfd >= 0);
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fd = open_terminal(path, flags | O_NOCTTY);
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if (fd < 0)
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return fd;
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return move_fd(fd, nfd, false);
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}
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static int acquire_path(const char *path, int flags, mode_t mode) {
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_cleanup_close_ int fd = -EBADF;
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int r;
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assert(path);
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if (IN_SET(flags & O_ACCMODE, O_WRONLY, O_RDWR))
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flags |= O_CREAT;
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fd = open(path, flags|O_NOCTTY, mode);
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if (fd >= 0)
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return TAKE_FD(fd);
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if (errno != ENXIO) /* ENXIO is returned when we try to open() an AF_UNIX file system socket on Linux */
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return -errno;
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/* So, it appears the specified path could be an AF_UNIX socket. Let's see if we can connect to it. */
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fd = socket(AF_UNIX, SOCK_STREAM, 0);
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if (fd < 0)
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return -errno;
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r = connect_unix_path(fd, AT_FDCWD, path);
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if (IN_SET(r, -ENOTSOCK, -EINVAL))
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/* Propagate initial error if we get ENOTSOCK or EINVAL, i.e. we have indication that this
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* wasn't an AF_UNIX socket after all */
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return -ENXIO;
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if (r < 0)
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return r;
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if ((flags & O_ACCMODE) == O_RDONLY)
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r = shutdown(fd, SHUT_WR);
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else if ((flags & O_ACCMODE) == O_WRONLY)
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r = shutdown(fd, SHUT_RD);
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else
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r = 0;
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if (r < 0)
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return -errno;
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return TAKE_FD(fd);
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}
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static int fixup_input(
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const ExecContext *context,
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int socket_fd,
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bool apply_tty_stdin) {
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ExecInput std_input;
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assert(context);
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std_input = context->std_input;
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if (is_terminal_input(std_input) && !apply_tty_stdin)
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return EXEC_INPUT_NULL;
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if (std_input == EXEC_INPUT_SOCKET && socket_fd < 0)
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return EXEC_INPUT_NULL;
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if (std_input == EXEC_INPUT_DATA && context->stdin_data_size == 0)
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return EXEC_INPUT_NULL;
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return std_input;
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}
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static int fixup_output(ExecOutput output, int socket_fd) {
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if (output == EXEC_OUTPUT_SOCKET && socket_fd < 0)
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return EXEC_OUTPUT_INHERIT;
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return output;
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}
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static int setup_input(
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const ExecContext *context,
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const ExecParameters *params,
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int socket_fd,
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const int named_iofds[static 3]) {
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ExecInput i;
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int r;
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assert(context);
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assert(params);
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assert(named_iofds);
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if (params->stdin_fd >= 0) {
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if (dup2(params->stdin_fd, STDIN_FILENO) < 0)
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return -errno;
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/* Try to make this the controlling tty, if it is a tty */
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if (isatty_safe(STDIN_FILENO))
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(void) ioctl(STDIN_FILENO, TIOCSCTTY, context->std_input == EXEC_INPUT_TTY_FORCE);
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return STDIN_FILENO;
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}
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i = fixup_input(context, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN);
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switch (i) {
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case EXEC_INPUT_NULL:
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return open_null_as(O_RDONLY, STDIN_FILENO);
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case EXEC_INPUT_TTY:
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case EXEC_INPUT_TTY_FORCE:
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case EXEC_INPUT_TTY_FAIL: {
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_cleanup_close_ int tty_fd = -EBADF;
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const char *tty_path;
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tty_path = ASSERT_PTR(exec_context_tty_path(context));
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tty_fd = acquire_terminal(tty_path,
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i == EXEC_INPUT_TTY_FAIL ? ACQUIRE_TERMINAL_TRY :
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i == EXEC_INPUT_TTY_FORCE ? ACQUIRE_TERMINAL_FORCE :
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ACQUIRE_TERMINAL_WAIT,
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USEC_INFINITY);
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if (tty_fd < 0)
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return tty_fd;
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r = move_fd(tty_fd, STDIN_FILENO, /* cloexec= */ false);
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if (r < 0)
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return r;
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TAKE_FD(tty_fd);
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return r;
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}
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case EXEC_INPUT_SOCKET:
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assert(socket_fd >= 0);
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return RET_NERRNO(dup2(socket_fd, STDIN_FILENO));
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case EXEC_INPUT_NAMED_FD:
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assert(named_iofds[STDIN_FILENO] >= 0);
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(void) fd_nonblock(named_iofds[STDIN_FILENO], false);
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return RET_NERRNO(dup2(named_iofds[STDIN_FILENO], STDIN_FILENO));
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case EXEC_INPUT_DATA: {
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int fd;
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fd = acquire_data_fd_full(context->stdin_data, context->stdin_data_size, /* flags = */ 0);
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if (fd < 0)
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return fd;
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return move_fd(fd, STDIN_FILENO, false);
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}
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case EXEC_INPUT_FILE: {
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bool rw;
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int fd;
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assert(context->stdio_file[STDIN_FILENO]);
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rw = (context->std_output == EXEC_OUTPUT_FILE && streq_ptr(context->stdio_file[STDIN_FILENO], context->stdio_file[STDOUT_FILENO])) ||
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(context->std_error == EXEC_OUTPUT_FILE && streq_ptr(context->stdio_file[STDIN_FILENO], context->stdio_file[STDERR_FILENO]));
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fd = acquire_path(context->stdio_file[STDIN_FILENO], rw ? O_RDWR : O_RDONLY, 0666 & ~context->umask);
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if (fd < 0)
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return fd;
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return move_fd(fd, STDIN_FILENO, false);
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}
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default:
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assert_not_reached();
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}
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}
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static bool can_inherit_stderr_from_stdout(
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const ExecContext *context,
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ExecOutput o,
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ExecOutput e) {
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assert(context);
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/* Returns true, if given the specified STDERR and STDOUT output we can directly dup() the stdout fd to the
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* stderr fd */
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if (e == EXEC_OUTPUT_INHERIT)
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return true;
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if (e != o)
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return false;
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if (e == EXEC_OUTPUT_NAMED_FD)
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return streq_ptr(context->stdio_fdname[STDOUT_FILENO], context->stdio_fdname[STDERR_FILENO]);
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|
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if (IN_SET(e, EXEC_OUTPUT_FILE, EXEC_OUTPUT_FILE_APPEND, EXEC_OUTPUT_FILE_TRUNCATE))
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return streq_ptr(context->stdio_file[STDOUT_FILENO], context->stdio_file[STDERR_FILENO]);
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return true;
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}
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|
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static int setup_output(
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const ExecContext *context,
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const ExecParameters *params,
|
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int fileno,
|
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int socket_fd,
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const int named_iofds[static 3],
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const char *ident,
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uid_t uid,
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gid_t gid,
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dev_t *journal_stream_dev,
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ino_t *journal_stream_ino) {
|
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|
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ExecOutput o;
|
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ExecInput i;
|
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int r;
|
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|
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assert(context);
|
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assert(params);
|
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assert(ident);
|
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assert(journal_stream_dev);
|
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assert(journal_stream_ino);
|
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|
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if (fileno == STDOUT_FILENO && params->stdout_fd >= 0) {
|
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|
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if (dup2(params->stdout_fd, STDOUT_FILENO) < 0)
|
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return -errno;
|
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|
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return STDOUT_FILENO;
|
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}
|
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|
||
if (fileno == STDERR_FILENO && params->stderr_fd >= 0) {
|
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if (dup2(params->stderr_fd, STDERR_FILENO) < 0)
|
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return -errno;
|
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|
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return STDERR_FILENO;
|
||
}
|
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|
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i = fixup_input(context, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN);
|
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o = fixup_output(context->std_output, socket_fd);
|
||
|
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// FIXME: we probably should spend some time here to verify that if we inherit an fd from stdin
|
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// (possibly indirect via inheritance from stdout) it is actually opened for write!
|
||
|
||
if (fileno == STDERR_FILENO) {
|
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ExecOutput e;
|
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e = fixup_output(context->std_error, socket_fd);
|
||
|
||
/* This expects the input and output are already set up */
|
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|
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/* Don't change the stderr file descriptor if we inherit all
|
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* the way and are not on a tty */
|
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if (e == EXEC_OUTPUT_INHERIT &&
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o == EXEC_OUTPUT_INHERIT &&
|
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i == EXEC_INPUT_NULL &&
|
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!is_terminal_input(context->std_input) &&
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getppid() != 1)
|
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return fileno;
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|
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/* Duplicate from stdout if possible */
|
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if (can_inherit_stderr_from_stdout(context, o, e))
|
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return RET_NERRNO(dup2(STDOUT_FILENO, fileno));
|
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|
||
o = e;
|
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|
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} else if (o == EXEC_OUTPUT_INHERIT) {
|
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/* If input got downgraded, inherit the original value */
|
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if (i == EXEC_INPUT_NULL && is_terminal_input(context->std_input))
|
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return open_terminal_as(exec_context_tty_path(context), O_WRONLY, fileno);
|
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|
||
/* If the input is connected to anything that's not a /dev/null or a data fd, inherit that... */
|
||
if (!IN_SET(i, EXEC_INPUT_NULL, EXEC_INPUT_DATA))
|
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return RET_NERRNO(dup2(STDIN_FILENO, fileno));
|
||
|
||
/* If we are not started from PID 1 we just inherit STDOUT from our parent process. */
|
||
if (getppid() != 1)
|
||
return fileno;
|
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|
||
/* We need to open /dev/null here anew, to get the right access mode. */
|
||
return open_null_as(O_WRONLY, fileno);
|
||
}
|
||
|
||
switch (o) {
|
||
|
||
case EXEC_OUTPUT_NULL:
|
||
return open_null_as(O_WRONLY, fileno);
|
||
|
||
case EXEC_OUTPUT_TTY:
|
||
if (is_terminal_input(i))
|
||
return RET_NERRNO(dup2(STDIN_FILENO, fileno));
|
||
|
||
return open_terminal_as(exec_context_tty_path(context), O_WRONLY, fileno);
|
||
|
||
case EXEC_OUTPUT_KMSG:
|
||
case EXEC_OUTPUT_KMSG_AND_CONSOLE:
|
||
case EXEC_OUTPUT_JOURNAL:
|
||
case EXEC_OUTPUT_JOURNAL_AND_CONSOLE:
|
||
r = connect_logger_as(context, params, o, ident, fileno, uid, gid);
|
||
if (r < 0) {
|
||
log_exec_warning_errno(context,
|
||
params,
|
||
r,
|
||
"Failed to connect %s to the journal socket, ignoring: %m",
|
||
fileno == STDOUT_FILENO ? "stdout" : "stderr");
|
||
r = open_null_as(O_WRONLY, fileno);
|
||
} else {
|
||
struct stat st;
|
||
|
||
/* If we connected this fd to the journal via a stream, patch the device/inode into the passed
|
||
* parameters, but only then. This is useful so that we can set $JOURNAL_STREAM that permits
|
||
* services to detect whether they are connected to the journal or not.
|
||
*
|
||
* If both stdout and stderr are connected to a stream then let's make sure to store the data
|
||
* about STDERR as that's usually the best way to do logging. */
|
||
|
||
if (fstat(fileno, &st) >= 0 &&
|
||
(*journal_stream_ino == 0 || fileno == STDERR_FILENO)) {
|
||
*journal_stream_dev = st.st_dev;
|
||
*journal_stream_ino = st.st_ino;
|
||
}
|
||
}
|
||
return r;
|
||
|
||
case EXEC_OUTPUT_SOCKET:
|
||
assert(socket_fd >= 0);
|
||
|
||
return RET_NERRNO(dup2(socket_fd, fileno));
|
||
|
||
case EXEC_OUTPUT_NAMED_FD:
|
||
assert(named_iofds[fileno] >= 0);
|
||
|
||
(void) fd_nonblock(named_iofds[fileno], false);
|
||
return RET_NERRNO(dup2(named_iofds[fileno], fileno));
|
||
|
||
case EXEC_OUTPUT_FILE:
|
||
case EXEC_OUTPUT_FILE_APPEND:
|
||
case EXEC_OUTPUT_FILE_TRUNCATE: {
|
||
bool rw;
|
||
int fd, flags;
|
||
|
||
assert(context->stdio_file[fileno]);
|
||
|
||
rw = context->std_input == EXEC_INPUT_FILE &&
|
||
streq_ptr(context->stdio_file[fileno], context->stdio_file[STDIN_FILENO]);
|
||
|
||
if (rw)
|
||
return RET_NERRNO(dup2(STDIN_FILENO, fileno));
|
||
|
||
flags = O_WRONLY;
|
||
if (o == EXEC_OUTPUT_FILE_APPEND)
|
||
flags |= O_APPEND;
|
||
else if (o == EXEC_OUTPUT_FILE_TRUNCATE)
|
||
flags |= O_TRUNC;
|
||
|
||
fd = acquire_path(context->stdio_file[fileno], flags, 0666 & ~context->umask);
|
||
if (fd < 0)
|
||
return fd;
|
||
|
||
return move_fd(fd, fileno, 0);
|
||
}
|
||
|
||
default:
|
||
assert_not_reached();
|
||
}
|
||
}
|
||
|
||
static int chown_terminal(int fd, uid_t uid) {
|
||
int r;
|
||
|
||
assert(fd >= 0);
|
||
|
||
/* Before we chown/chmod the TTY, let's ensure this is actually a tty */
|
||
if (!isatty_safe(fd))
|
||
return 0;
|
||
|
||
/* This might fail. What matters are the results. */
|
||
r = fchmod_and_chown(fd, TTY_MODE, uid, GID_INVALID);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
return 1;
|
||
}
|
||
|
||
static int setup_confirm_stdio(
|
||
const ExecContext *context,
|
||
const char *vc,
|
||
int *ret_saved_stdin,
|
||
int *ret_saved_stdout) {
|
||
|
||
_cleanup_close_ int fd = -EBADF, saved_stdin = -EBADF, saved_stdout = -EBADF;
|
||
int r;
|
||
|
||
assert(ret_saved_stdin);
|
||
assert(ret_saved_stdout);
|
||
|
||
saved_stdin = fcntl(STDIN_FILENO, F_DUPFD_CLOEXEC, 3);
|
||
if (saved_stdin < 0)
|
||
return -errno;
|
||
|
||
saved_stdout = fcntl(STDOUT_FILENO, F_DUPFD_CLOEXEC, 3);
|
||
if (saved_stdout < 0)
|
||
return -errno;
|
||
|
||
fd = acquire_terminal(vc, ACQUIRE_TERMINAL_WAIT, DEFAULT_CONFIRM_USEC);
|
||
if (fd < 0)
|
||
return fd;
|
||
|
||
_cleanup_close_ int lock_fd = lock_dev_console();
|
||
if (lock_fd < 0)
|
||
log_debug_errno(lock_fd, "Failed to lock /dev/console, ignoring: %m");
|
||
|
||
r = chown_terminal(fd, getuid());
|
||
if (r < 0)
|
||
return r;
|
||
|
||
r = terminal_reset_defensive(fd, /* switch_to_text= */ true);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
r = exec_context_apply_tty_size(context, fd, fd, vc);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
r = rearrange_stdio(fd, fd, STDERR_FILENO); /* Invalidates 'fd' also on failure */
|
||
TAKE_FD(fd);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
*ret_saved_stdin = TAKE_FD(saved_stdin);
|
||
*ret_saved_stdout = TAKE_FD(saved_stdout);
|
||
return 0;
|
||
}
|
||
|
||
static void write_confirm_error_fd(int err, int fd, const char *unit_id) {
|
||
assert(err != 0);
|
||
assert(fd >= 0);
|
||
assert(unit_id);
|
||
|
||
errno = abs(err);
|
||
|
||
if (errno == ETIMEDOUT)
|
||
dprintf(fd, "Confirmation question timed out for %s, assuming positive response.\n", unit_id);
|
||
else
|
||
dprintf(fd, "Couldn't ask confirmation for %s, assuming positive response: %m\n", unit_id);
|
||
}
|
||
|
||
static void write_confirm_error(int err, const char *vc, const char *unit_id) {
|
||
_cleanup_close_ int fd = -EBADF;
|
||
|
||
assert(vc);
|
||
|
||
fd = open_terminal(vc, O_WRONLY|O_NOCTTY|O_CLOEXEC);
|
||
if (fd < 0)
|
||
return;
|
||
|
||
write_confirm_error_fd(err, fd, unit_id);
|
||
}
|
||
|
||
static int restore_confirm_stdio(int *saved_stdin, int *saved_stdout) {
|
||
int r = 0;
|
||
|
||
assert(saved_stdin);
|
||
assert(saved_stdout);
|
||
|
||
release_terminal();
|
||
|
||
if (*saved_stdin >= 0)
|
||
if (dup2(*saved_stdin, STDIN_FILENO) < 0)
|
||
r = -errno;
|
||
|
||
if (*saved_stdout >= 0)
|
||
if (dup2(*saved_stdout, STDOUT_FILENO) < 0)
|
||
r = -errno;
|
||
|
||
*saved_stdin = safe_close(*saved_stdin);
|
||
*saved_stdout = safe_close(*saved_stdout);
|
||
|
||
return r;
|
||
}
|
||
|
||
enum {
|
||
CONFIRM_PRETEND_FAILURE = -1,
|
||
CONFIRM_PRETEND_SUCCESS = 0,
|
||
CONFIRM_EXECUTE = 1,
|
||
};
|
||
|
||
static bool confirm_spawn_disabled(void) {
|
||
return access("/run/systemd/confirm_spawn_disabled", F_OK) >= 0;
|
||
}
|
||
|
||
static int ask_for_confirmation(const ExecContext *context, const ExecParameters *params, const char *cmdline) {
|
||
int saved_stdout = -EBADF, saved_stdin = -EBADF, r;
|
||
_cleanup_free_ char *e = NULL;
|
||
char c;
|
||
|
||
assert(context);
|
||
assert(params);
|
||
|
||
/* For any internal errors, assume a positive response. */
|
||
r = setup_confirm_stdio(context, params->confirm_spawn, &saved_stdin, &saved_stdout);
|
||
if (r < 0) {
|
||
write_confirm_error(r, params->confirm_spawn, params->unit_id);
|
||
return CONFIRM_EXECUTE;
|
||
}
|
||
|
||
/* confirm_spawn might have been disabled while we were sleeping. */
|
||
if (!params->confirm_spawn || confirm_spawn_disabled()) {
|
||
r = 1;
|
||
goto restore_stdio;
|
||
}
|
||
|
||
e = ellipsize(cmdline, 60, 100);
|
||
if (!e) {
|
||
log_oom();
|
||
r = CONFIRM_EXECUTE;
|
||
goto restore_stdio;
|
||
}
|
||
|
||
for (;;) {
|
||
r = ask_char(&c, "yfshiDjcn", "Execute %s? [y, f, s – h for help] ", e);
|
||
if (r < 0) {
|
||
write_confirm_error_fd(r, STDOUT_FILENO, params->unit_id);
|
||
r = CONFIRM_EXECUTE;
|
||
goto restore_stdio;
|
||
}
|
||
|
||
switch (c) {
|
||
case 'c':
|
||
printf("Resuming normal execution.\n");
|
||
manager_disable_confirm_spawn();
|
||
r = 1;
|
||
break;
|
||
case 'D':
|
||
printf(" Unit: %s\n",
|
||
params->unit_id);
|
||
exec_context_dump(context, stdout, " ");
|
||
exec_params_dump(params, stdout, " ");
|
||
continue; /* ask again */
|
||
case 'f':
|
||
printf("Failing execution.\n");
|
||
r = CONFIRM_PRETEND_FAILURE;
|
||
break;
|
||
case 'h':
|
||
printf(" c - continue, proceed without asking anymore\n"
|
||
" D - dump, show the state of the unit\n"
|
||
" f - fail, don't execute the command and pretend it failed\n"
|
||
" h - help\n"
|
||
" i - info, show a short summary of the unit\n"
|
||
" j - jobs, show jobs that are in progress\n"
|
||
" s - skip, don't execute the command and pretend it succeeded\n"
|
||
" y - yes, execute the command\n");
|
||
continue; /* ask again */
|
||
case 'i':
|
||
printf(" Unit: %s\n"
|
||
" Command: %s\n",
|
||
params->unit_id, cmdline);
|
||
continue; /* ask again */
|
||
case 'j':
|
||
if (sigqueue(getppid(),
|
||
SIGRTMIN+18,
|
||
(const union sigval) { .sival_int = MANAGER_SIGNAL_COMMAND_DUMP_JOBS }) < 0)
|
||
return -errno;
|
||
|
||
continue; /* ask again */
|
||
case 'n':
|
||
/* 'n' was removed in favor of 'f'. */
|
||
printf("Didn't understand 'n', did you mean 'f'?\n");
|
||
continue; /* ask again */
|
||
case 's':
|
||
printf("Skipping execution.\n");
|
||
r = CONFIRM_PRETEND_SUCCESS;
|
||
break;
|
||
case 'y':
|
||
r = CONFIRM_EXECUTE;
|
||
break;
|
||
default:
|
||
assert_not_reached();
|
||
}
|
||
break;
|
||
}
|
||
|
||
restore_stdio:
|
||
restore_confirm_stdio(&saved_stdin, &saved_stdout);
|
||
return r;
|
||
}
|
||
|
||
static int get_fixed_user(
|
||
const char *user_or_uid,
|
||
const char **ret_username,
|
||
uid_t *ret_uid,
|
||
gid_t *ret_gid,
|
||
const char **ret_home,
|
||
const char **ret_shell) {
|
||
|
||
int r;
|
||
|
||
assert(user_or_uid);
|
||
assert(ret_username);
|
||
|
||
r = get_user_creds(&user_or_uid, ret_uid, ret_gid, ret_home, ret_shell, USER_CREDS_CLEAN);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
/* user_or_uid is normalized by get_user_creds to username */
|
||
*ret_username = user_or_uid;
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int get_fixed_group(
|
||
const char *group_or_gid,
|
||
const char **ret_groupname,
|
||
gid_t *ret_gid) {
|
||
|
||
int r;
|
||
|
||
assert(group_or_gid);
|
||
assert(ret_groupname);
|
||
|
||
r = get_group_creds(&group_or_gid, ret_gid, /* flags = */ 0);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
/* group_or_gid is normalized by get_group_creds to groupname */
|
||
*ret_groupname = group_or_gid;
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int get_supplementary_groups(const ExecContext *c, const char *user,
|
||
const char *group, gid_t gid,
|
||
gid_t **supplementary_gids, int *ngids) {
|
||
int r, k = 0;
|
||
int ngroups_max;
|
||
bool keep_groups = false;
|
||
gid_t *groups = NULL;
|
||
_cleanup_free_ gid_t *l_gids = NULL;
|
||
|
||
assert(c);
|
||
|
||
/*
|
||
* If user is given, then lookup GID and supplementary groups list.
|
||
* We avoid NSS lookups for gid=0. Also we have to initialize groups
|
||
* here and as early as possible so we keep the list of supplementary
|
||
* groups of the caller.
|
||
*/
|
||
if (user && gid_is_valid(gid) && gid != 0) {
|
||
/* First step, initialize groups from /etc/groups */
|
||
if (initgroups(user, gid) < 0)
|
||
return -errno;
|
||
|
||
keep_groups = true;
|
||
}
|
||
|
||
if (strv_isempty(c->supplementary_groups))
|
||
return 0;
|
||
|
||
/*
|
||
* If SupplementaryGroups= was passed then NGROUPS_MAX has to
|
||
* be positive, otherwise fail.
|
||
*/
|
||
errno = 0;
|
||
ngroups_max = (int) sysconf(_SC_NGROUPS_MAX);
|
||
if (ngroups_max <= 0)
|
||
return errno_or_else(EOPNOTSUPP);
|
||
|
||
l_gids = new(gid_t, ngroups_max);
|
||
if (!l_gids)
|
||
return -ENOMEM;
|
||
|
||
if (keep_groups) {
|
||
/*
|
||
* Lookup the list of groups that the user belongs to, we
|
||
* avoid NSS lookups here too for gid=0.
|
||
*/
|
||
k = ngroups_max;
|
||
if (getgrouplist(user, gid, l_gids, &k) < 0)
|
||
return -EINVAL;
|
||
} else
|
||
k = 0;
|
||
|
||
STRV_FOREACH(i, c->supplementary_groups) {
|
||
const char *g;
|
||
|
||
if (k >= ngroups_max)
|
||
return -E2BIG;
|
||
|
||
g = *i;
|
||
r = get_group_creds(&g, l_gids+k, 0);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
k++;
|
||
}
|
||
|
||
/*
|
||
* Sets ngids to zero to drop all supplementary groups, happens
|
||
* when we are under root and SupplementaryGroups= is empty.
|
||
*/
|
||
if (k == 0) {
|
||
*ngids = 0;
|
||
return 0;
|
||
}
|
||
|
||
/* Otherwise get the final list of supplementary groups */
|
||
groups = memdup(l_gids, sizeof(gid_t) * k);
|
||
if (!groups)
|
||
return -ENOMEM;
|
||
|
||
*supplementary_gids = groups;
|
||
*ngids = k;
|
||
|
||
groups = NULL;
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int enforce_groups(gid_t gid, const gid_t *supplementary_gids, int ngids) {
|
||
int r;
|
||
|
||
/* Handle SupplementaryGroups= if it is not empty */
|
||
if (ngids > 0) {
|
||
r = maybe_setgroups(ngids, supplementary_gids);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
if (gid_is_valid(gid)) {
|
||
/* Then set our gids */
|
||
if (setresgid(gid, gid, gid) < 0)
|
||
return -errno;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int set_securebits(unsigned bits, unsigned mask) {
|
||
unsigned applied;
|
||
int current;
|
||
|
||
current = prctl(PR_GET_SECUREBITS);
|
||
if (current < 0)
|
||
return -errno;
|
||
|
||
/* Clear all securebits defined in mask and set bits */
|
||
applied = ((unsigned) current & ~mask) | bits;
|
||
if ((unsigned) current == applied)
|
||
return 0;
|
||
|
||
if (prctl(PR_SET_SECUREBITS, applied) < 0)
|
||
return -errno;
|
||
|
||
return 1;
|
||
}
|
||
|
||
static int enforce_user(
|
||
const ExecContext *context,
|
||
uid_t uid,
|
||
uint64_t capability_ambient_set) {
|
||
assert(context);
|
||
int r;
|
||
|
||
if (!uid_is_valid(uid))
|
||
return 0;
|
||
|
||
/* Sets (but doesn't look up) the UIS and makes sure we keep the capabilities while doing so. For
|
||
* setting secure bits the capability CAP_SETPCAP is required, so we also need keep-caps in this
|
||
* case. */
|
||
|
||
if ((capability_ambient_set != 0 || context->secure_bits != 0) && uid != 0) {
|
||
|
||
/* First step: If we need to keep capabilities but drop privileges we need to make sure we
|
||
* keep our caps, while we drop privileges. Add KEEP_CAPS to the securebits */
|
||
r = set_securebits(1U << SECURE_KEEP_CAPS, 0);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
/* Second step: actually set the uids */
|
||
if (setresuid(uid, uid, uid) < 0)
|
||
return -errno;
|
||
|
||
/* At this point we should have all necessary capabilities but are otherwise a normal user. However,
|
||
* the caps might got corrupted due to the setresuid() so we need clean them up later. This is done
|
||
* outside of this call. */
|
||
return 0;
|
||
}
|
||
|
||
#if HAVE_PAM
|
||
|
||
static int null_conv(
|
||
int num_msg,
|
||
const struct pam_message **msg,
|
||
struct pam_response **resp,
|
||
void *appdata_ptr) {
|
||
|
||
/* We don't support conversations */
|
||
|
||
return PAM_CONV_ERR;
|
||
}
|
||
|
||
static int pam_close_session_and_delete_credentials(pam_handle_t *handle, int flags) {
|
||
int r, s;
|
||
|
||
assert(handle);
|
||
|
||
r = pam_close_session(handle, flags);
|
||
if (r != PAM_SUCCESS)
|
||
log_debug("pam_close_session() failed: %s", pam_strerror(handle, r));
|
||
|
||
s = pam_setcred(handle, PAM_DELETE_CRED | flags);
|
||
if (s != PAM_SUCCESS)
|
||
log_debug("pam_setcred(PAM_DELETE_CRED) failed: %s", pam_strerror(handle, s));
|
||
|
||
return r != PAM_SUCCESS ? r : s;
|
||
}
|
||
|
||
#endif
|
||
|
||
static int setup_pam(
|
||
const char *name,
|
||
const char *user,
|
||
uid_t uid,
|
||
gid_t gid,
|
||
const char *tty,
|
||
char ***env, /* updated on success */
|
||
const int fds[], size_t n_fds,
|
||
int exec_fd) {
|
||
|
||
#if HAVE_PAM
|
||
|
||
static const struct pam_conv conv = {
|
||
.conv = null_conv,
|
||
.appdata_ptr = NULL
|
||
};
|
||
|
||
_cleanup_(barrier_destroy) Barrier barrier = BARRIER_NULL;
|
||
_cleanup_strv_free_ char **e = NULL;
|
||
pam_handle_t *handle = NULL;
|
||
sigset_t old_ss;
|
||
int pam_code = PAM_SUCCESS, r;
|
||
bool close_session = false;
|
||
pid_t parent_pid;
|
||
int flags = 0;
|
||
|
||
assert(name);
|
||
assert(user);
|
||
assert(env);
|
||
|
||
/* We set up PAM in the parent process, then fork. The child
|
||
* will then stay around until killed via PR_GET_PDEATHSIG or
|
||
* systemd via the cgroup logic. It will then remove the PAM
|
||
* session again. The parent process will exec() the actual
|
||
* daemon. We do things this way to ensure that the main PID
|
||
* of the daemon is the one we initially fork()ed. */
|
||
|
||
r = barrier_create(&barrier);
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
if (log_get_max_level() < LOG_DEBUG)
|
||
flags |= PAM_SILENT;
|
||
|
||
pam_code = pam_start(name, user, &conv, &handle);
|
||
if (pam_code != PAM_SUCCESS) {
|
||
handle = NULL;
|
||
goto fail;
|
||
}
|
||
|
||
if (!tty) {
|
||
_cleanup_free_ char *q = NULL;
|
||
|
||
/* Hmm, so no TTY was explicitly passed, but an fd passed to us directly might be a TTY. Let's figure
|
||
* out if that's the case, and read the TTY off it. */
|
||
|
||
if (getttyname_malloc(STDIN_FILENO, &q) >= 0)
|
||
tty = strjoina("/dev/", q);
|
||
}
|
||
|
||
if (tty) {
|
||
pam_code = pam_set_item(handle, PAM_TTY, tty);
|
||
if (pam_code != PAM_SUCCESS)
|
||
goto fail;
|
||
}
|
||
|
||
STRV_FOREACH(nv, *env) {
|
||
pam_code = pam_putenv(handle, *nv);
|
||
if (pam_code != PAM_SUCCESS)
|
||
goto fail;
|
||
}
|
||
|
||
pam_code = pam_acct_mgmt(handle, flags);
|
||
if (pam_code != PAM_SUCCESS)
|
||
goto fail;
|
||
|
||
pam_code = pam_setcred(handle, PAM_ESTABLISH_CRED | flags);
|
||
if (pam_code != PAM_SUCCESS)
|
||
log_debug("pam_setcred(PAM_ESTABLISH_CRED) failed, ignoring: %s", pam_strerror(handle, pam_code));
|
||
|
||
pam_code = pam_open_session(handle, flags);
|
||
if (pam_code != PAM_SUCCESS)
|
||
goto fail;
|
||
|
||
close_session = true;
|
||
|
||
e = pam_getenvlist(handle);
|
||
if (!e) {
|
||
pam_code = PAM_BUF_ERR;
|
||
goto fail;
|
||
}
|
||
|
||
/* Block SIGTERM, so that we know that it won't get lost in the child */
|
||
|
||
assert_se(sigprocmask_many(SIG_BLOCK, &old_ss, SIGTERM) >= 0);
|
||
|
||
parent_pid = getpid_cached();
|
||
|
||
r = safe_fork("(sd-pam)", 0, NULL);
|
||
if (r < 0)
|
||
goto fail;
|
||
if (r == 0) {
|
||
int ret = EXIT_PAM;
|
||
|
||
/* The child's job is to reset the PAM session on termination */
|
||
barrier_set_role(&barrier, BARRIER_CHILD);
|
||
|
||
/* Make sure we don't keep open the passed fds in this child. We assume that otherwise only
|
||
* those fds are open here that have been opened by PAM. */
|
||
(void) close_many(fds, n_fds);
|
||
|
||
/* Also close the 'exec_fd' in the child, since the service manager waits for the EOF induced
|
||
* by the execve() to wait for completion, and if we'd keep the fd open here in the child
|
||
* we'd never signal completion. */
|
||
exec_fd = safe_close(exec_fd);
|
||
|
||
/* Drop privileges - we don't need any to pam_close_session and this will make
|
||
* PR_SET_PDEATHSIG work in most cases. If this fails, ignore the error - but expect sd-pam
|
||
* threads to fail to exit normally */
|
||
|
||
r = fully_set_uid_gid(uid, gid, /* supplementary_gids= */ NULL, /* n_supplementary_gids= */ 0);
|
||
if (r < 0)
|
||
log_warning_errno(r, "Failed to drop privileges in sd-pam: %m");
|
||
|
||
(void) ignore_signals(SIGPIPE);
|
||
|
||
/* Wait until our parent died. This will only work if the above setresuid() succeeds,
|
||
* otherwise the kernel will not allow unprivileged parents kill their privileged children
|
||
* this way. We rely on the control groups kill logic to do the rest for us. */
|
||
if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0)
|
||
goto child_finish;
|
||
|
||
/* Tell the parent that our setup is done. This is especially important regarding dropping
|
||
* privileges. Otherwise, unit setup might race against our setresuid(2) call.
|
||
*
|
||
* If the parent aborted, we'll detect this below, hence ignore return failure here. */
|
||
(void) barrier_place(&barrier);
|
||
|
||
/* Check if our parent process might already have died? */
|
||
if (getppid() == parent_pid) {
|
||
sigset_t ss;
|
||
int sig;
|
||
|
||
assert_se(sigemptyset(&ss) >= 0);
|
||
assert_se(sigaddset(&ss, SIGTERM) >= 0);
|
||
|
||
assert_se(sigwait(&ss, &sig) == 0);
|
||
assert(sig == SIGTERM);
|
||
}
|
||
|
||
/* If our parent died we'll end the session */
|
||
if (getppid() != parent_pid) {
|
||
pam_code = pam_close_session_and_delete_credentials(handle, flags);
|
||
if (pam_code != PAM_SUCCESS)
|
||
goto child_finish;
|
||
}
|
||
|
||
ret = 0;
|
||
|
||
child_finish:
|
||
/* NB: pam_end() when called in child processes should set PAM_DATA_SILENT to let the module
|
||
* know about this. See pam_end(3) */
|
||
(void) pam_end(handle, pam_code | flags | PAM_DATA_SILENT);
|
||
_exit(ret);
|
||
}
|
||
|
||
barrier_set_role(&barrier, BARRIER_PARENT);
|
||
|
||
/* If the child was forked off successfully it will do all the cleanups, so forget about the handle
|
||
* here. */
|
||
handle = NULL;
|
||
|
||
/* Unblock SIGTERM again in the parent */
|
||
assert_se(sigprocmask(SIG_SETMASK, &old_ss, NULL) >= 0);
|
||
|
||
/* We close the log explicitly here, since the PAM modules might have opened it, but we don't want
|
||
* this fd around. */
|
||
closelog();
|
||
|
||
/* Synchronously wait for the child to initialize. We don't care for errors as we cannot
|
||
* recover. However, warn loudly if it happens. */
|
||
if (!barrier_place_and_sync(&barrier))
|
||
log_error("PAM initialization failed");
|
||
|
||
return strv_free_and_replace(*env, e);
|
||
|
||
fail:
|
||
if (pam_code != PAM_SUCCESS) {
|
||
log_error("PAM failed: %s", pam_strerror(handle, pam_code));
|
||
r = -EPERM; /* PAM errors do not map to errno */
|
||
} else
|
||
log_error_errno(r, "PAM failed: %m");
|
||
|
||
if (handle) {
|
||
if (close_session)
|
||
pam_code = pam_close_session_and_delete_credentials(handle, flags);
|
||
|
||
(void) pam_end(handle, pam_code | flags);
|
||
}
|
||
|
||
closelog();
|
||
return r;
|
||
#else
|
||
return 0;
|
||
#endif
|
||
}
|
||
|
||
static void rename_process_from_path(const char *path) {
|
||
_cleanup_free_ char *buf = NULL;
|
||
const char *p;
|
||
|
||
assert(path);
|
||
|
||
/* This resulting string must fit in 10 chars (i.e. the length of "/sbin/init") to look pretty in
|
||
* /bin/ps */
|
||
|
||
if (path_extract_filename(path, &buf) < 0) {
|
||
rename_process("(...)");
|
||
return;
|
||
}
|
||
|
||
size_t l = strlen(buf);
|
||
if (l > 8) {
|
||
/* The end of the process name is usually more interesting, since the first bit might just be
|
||
* "systemd-" */
|
||
p = buf + l - 8;
|
||
l = 8;
|
||
} else
|
||
p = buf;
|
||
|
||
char process_name[11];
|
||
process_name[0] = '(';
|
||
memcpy(process_name+1, p, l);
|
||
process_name[1+l] = ')';
|
||
process_name[1+l+1] = 0;
|
||
|
||
(void) rename_process(process_name);
|
||
}
|
||
|
||
static bool context_has_address_families(const ExecContext *c) {
|
||
assert(c);
|
||
|
||
return c->address_families_allow_list ||
|
||
!set_isempty(c->address_families);
|
||
}
|
||
|
||
static bool context_has_syscall_filters(const ExecContext *c) {
|
||
assert(c);
|
||
|
||
return c->syscall_allow_list ||
|
||
!hashmap_isempty(c->syscall_filter);
|
||
}
|
||
|
||
static bool context_has_syscall_logs(const ExecContext *c) {
|
||
assert(c);
|
||
|
||
return c->syscall_log_allow_list ||
|
||
!hashmap_isempty(c->syscall_log);
|
||
}
|
||
|
||
static bool context_has_seccomp(const ExecContext *c) {
|
||
/* We need NNP if we have any form of seccomp and are unprivileged */
|
||
return c->lock_personality ||
|
||
c->memory_deny_write_execute ||
|
||
c->private_devices ||
|
||
c->protect_clock ||
|
||
c->protect_hostname == PROTECT_HOSTNAME_YES ||
|
||
c->protect_kernel_tunables ||
|
||
c->protect_kernel_modules ||
|
||
c->protect_kernel_logs ||
|
||
context_has_address_families(c) ||
|
||
exec_context_restrict_namespaces_set(c) ||
|
||
c->restrict_realtime ||
|
||
c->restrict_suid_sgid ||
|
||
!set_isempty(c->syscall_archs) ||
|
||
context_has_syscall_filters(c) ||
|
||
context_has_syscall_logs(c);
|
||
}
|
||
|
||
static bool context_has_no_new_privileges(const ExecContext *c) {
|
||
assert(c);
|
||
|
||
if (c->no_new_privileges)
|
||
return true;
|
||
|
||
if (have_effective_cap(CAP_SYS_ADMIN) > 0) /* if we are privileged, we don't need NNP */
|
||
return false;
|
||
|
||
return context_has_seccomp(c);
|
||
}
|
||
|
||
#if HAVE_SECCOMP
|
||
|
||
static bool seccomp_allows_drop_privileges(const ExecContext *c) {
|
||
void *id, *val;
|
||
bool has_capget = false, has_capset = false, has_prctl = false;
|
||
|
||
assert(c);
|
||
|
||
/* No syscall filter, we are allowed to drop privileges */
|
||
if (hashmap_isempty(c->syscall_filter))
|
||
return true;
|
||
|
||
HASHMAP_FOREACH_KEY(val, id, c->syscall_filter) {
|
||
_cleanup_free_ char *name = NULL;
|
||
|
||
name = seccomp_syscall_resolve_num_arch(SCMP_ARCH_NATIVE, PTR_TO_INT(id) - 1);
|
||
|
||
if (streq(name, "capget"))
|
||
has_capget = true;
|
||
else if (streq(name, "capset"))
|
||
has_capset = true;
|
||
else if (streq(name, "prctl"))
|
||
has_prctl = true;
|
||
}
|
||
|
||
if (c->syscall_allow_list)
|
||
return has_capget && has_capset && has_prctl;
|
||
else
|
||
return !(has_capget || has_capset || has_prctl);
|
||
}
|
||
|
||
static bool skip_seccomp_unavailable(const ExecContext *c, const ExecParameters *p, const char* msg) {
|
||
|
||
if (is_seccomp_available())
|
||
return false;
|
||
|
||
log_exec_debug(c, p, "SECCOMP features not detected in the kernel, skipping %s", msg);
|
||
return true;
|
||
}
|
||
|
||
static int apply_syscall_filter(const ExecContext *c, const ExecParameters *p) {
|
||
uint32_t negative_action, default_action, action;
|
||
int r;
|
||
|
||
assert(c);
|
||
assert(p);
|
||
|
||
if (!context_has_syscall_filters(c))
|
||
return 0;
|
||
|
||
if (skip_seccomp_unavailable(c, p, "SystemCallFilter="))
|
||
return 0;
|
||
|
||
negative_action = c->syscall_errno == SECCOMP_ERROR_NUMBER_KILL ? scmp_act_kill_process() : SCMP_ACT_ERRNO(c->syscall_errno);
|
||
|
||
if (c->syscall_allow_list) {
|
||
default_action = negative_action;
|
||
action = SCMP_ACT_ALLOW;
|
||
} else {
|
||
default_action = SCMP_ACT_ALLOW;
|
||
action = negative_action;
|
||
}
|
||
|
||
/* Sending over exec_fd or handoff_timestamp_fd requires write() syscall. */
|
||
if (p->exec_fd >= 0 || p->handoff_timestamp_fd >= 0) {
|
||
r = seccomp_filter_set_add_by_name(c->syscall_filter, c->syscall_allow_list, "write");
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
return seccomp_load_syscall_filter_set_raw(default_action, c->syscall_filter, action, false);
|
||
}
|
||
|
||
static int apply_syscall_log(const ExecContext *c, const ExecParameters *p) {
|
||
#ifdef SCMP_ACT_LOG
|
||
uint32_t default_action, action;
|
||
#endif
|
||
|
||
assert(c);
|
||
assert(p);
|
||
|
||
if (!context_has_syscall_logs(c))
|
||
return 0;
|
||
|
||
#ifdef SCMP_ACT_LOG
|
||
if (skip_seccomp_unavailable(c, p, "SystemCallLog="))
|
||
return 0;
|
||
|
||
if (c->syscall_log_allow_list) {
|
||
/* Log nothing but the ones listed */
|
||
default_action = SCMP_ACT_ALLOW;
|
||
action = SCMP_ACT_LOG;
|
||
} else {
|
||
/* Log everything but the ones listed */
|
||
default_action = SCMP_ACT_LOG;
|
||
action = SCMP_ACT_ALLOW;
|
||
}
|
||
|
||
return seccomp_load_syscall_filter_set_raw(default_action, c->syscall_log, action, false);
|
||
#else
|
||
/* old libseccomp */
|
||
log_exec_debug(c, p, "SECCOMP feature SCMP_ACT_LOG not available, skipping SystemCallLog=");
|
||
return 0;
|
||
#endif
|
||
}
|
||
|
||
static int apply_syscall_archs(const ExecContext *c, const ExecParameters *p) {
|
||
assert(c);
|
||
assert(p);
|
||
|
||
if (set_isempty(c->syscall_archs))
|
||
return 0;
|
||
|
||
if (skip_seccomp_unavailable(c, p, "SystemCallArchitectures="))
|
||
return 0;
|
||
|
||
return seccomp_restrict_archs(c->syscall_archs);
|
||
}
|
||
|
||
static int apply_address_families(const ExecContext *c, const ExecParameters *p) {
|
||
assert(c);
|
||
assert(p);
|
||
|
||
if (!context_has_address_families(c))
|
||
return 0;
|
||
|
||
if (skip_seccomp_unavailable(c, p, "RestrictAddressFamilies="))
|
||
return 0;
|
||
|
||
return seccomp_restrict_address_families(c->address_families, c->address_families_allow_list);
|
||
}
|
||
|
||
static int apply_memory_deny_write_execute(const ExecContext *c, const ExecParameters *p) {
|
||
int r;
|
||
|
||
assert(c);
|
||
assert(p);
|
||
|
||
if (!c->memory_deny_write_execute)
|
||
return 0;
|
||
|
||
/* use prctl() if kernel supports it (6.3) */
|
||
r = prctl(PR_SET_MDWE, PR_MDWE_REFUSE_EXEC_GAIN, 0, 0, 0);
|
||
if (r == 0) {
|
||
log_exec_debug(c, p, "Enabled MemoryDenyWriteExecute= with PR_SET_MDWE");
|
||
return 0;
|
||
}
|
||
if (r < 0 && errno != EINVAL)
|
||
return log_exec_debug_errno(c,
|
||
p,
|
||
errno,
|
||
"Failed to enable MemoryDenyWriteExecute= with PR_SET_MDWE: %m");
|
||
/* else use seccomp */
|
||
log_exec_debug(c, p, "Kernel doesn't support PR_SET_MDWE: falling back to seccomp");
|
||
|
||
if (skip_seccomp_unavailable(c, p, "MemoryDenyWriteExecute="))
|
||
return 0;
|
||
|
||
return seccomp_memory_deny_write_execute();
|
||
}
|
||
|
||
static int apply_restrict_realtime(const ExecContext *c, const ExecParameters *p) {
|
||
assert(c);
|
||
assert(p);
|
||
|
||
if (!c->restrict_realtime)
|
||
return 0;
|
||
|
||
if (skip_seccomp_unavailable(c, p, "RestrictRealtime="))
|
||
return 0;
|
||
|
||
return seccomp_restrict_realtime();
|
||
}
|
||
|
||
static int apply_restrict_suid_sgid(const ExecContext *c, const ExecParameters *p) {
|
||
assert(c);
|
||
assert(p);
|
||
|
||
if (!c->restrict_suid_sgid)
|
||
return 0;
|
||
|
||
if (skip_seccomp_unavailable(c, p, "RestrictSUIDSGID="))
|
||
return 0;
|
||
|
||
return seccomp_restrict_suid_sgid();
|
||
}
|
||
|
||
static int apply_protect_sysctl(const ExecContext *c, const ExecParameters *p) {
|
||
assert(c);
|
||
assert(p);
|
||
|
||
/* Turn off the legacy sysctl() system call. Many distributions turn this off while building the kernel, but
|
||
* let's protect even those systems where this is left on in the kernel. */
|
||
|
||
if (!c->protect_kernel_tunables)
|
||
return 0;
|
||
|
||
if (skip_seccomp_unavailable(c, p, "ProtectKernelTunables="))
|
||
return 0;
|
||
|
||
return seccomp_protect_sysctl();
|
||
}
|
||
|
||
static int apply_protect_kernel_modules(const ExecContext *c, const ExecParameters *p) {
|
||
assert(c);
|
||
assert(p);
|
||
|
||
/* Turn off module syscalls on ProtectKernelModules=yes */
|
||
|
||
if (!c->protect_kernel_modules)
|
||
return 0;
|
||
|
||
if (skip_seccomp_unavailable(c, p, "ProtectKernelModules="))
|
||
return 0;
|
||
|
||
return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_MODULE, SCMP_ACT_ERRNO(EPERM), false);
|
||
}
|
||
|
||
static int apply_protect_kernel_logs(const ExecContext *c, const ExecParameters *p) {
|
||
assert(c);
|
||
assert(p);
|
||
|
||
if (!c->protect_kernel_logs)
|
||
return 0;
|
||
|
||
if (skip_seccomp_unavailable(c, p, "ProtectKernelLogs="))
|
||
return 0;
|
||
|
||
return seccomp_protect_syslog();
|
||
}
|
||
|
||
static int apply_protect_clock(const ExecContext *c, const ExecParameters *p) {
|
||
assert(c);
|
||
assert(p);
|
||
|
||
if (!c->protect_clock)
|
||
return 0;
|
||
|
||
if (skip_seccomp_unavailable(c, p, "ProtectClock="))
|
||
return 0;
|
||
|
||
return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_CLOCK, SCMP_ACT_ERRNO(EPERM), false);
|
||
}
|
||
|
||
static int apply_private_devices(const ExecContext *c, const ExecParameters *p) {
|
||
assert(c);
|
||
assert(p);
|
||
|
||
/* If PrivateDevices= is set, also turn off iopl and all @raw-io syscalls. */
|
||
|
||
if (!c->private_devices)
|
||
return 0;
|
||
|
||
if (skip_seccomp_unavailable(c, p, "PrivateDevices="))
|
||
return 0;
|
||
|
||
return seccomp_load_syscall_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_RAW_IO, SCMP_ACT_ERRNO(EPERM), false);
|
||
}
|
||
|
||
static int apply_restrict_namespaces(const ExecContext *c, const ExecParameters *p) {
|
||
assert(c);
|
||
assert(p);
|
||
|
||
if (!exec_context_restrict_namespaces_set(c))
|
||
return 0;
|
||
|
||
if (skip_seccomp_unavailable(c, p, "RestrictNamespaces="))
|
||
return 0;
|
||
|
||
return seccomp_restrict_namespaces(c->restrict_namespaces);
|
||
}
|
||
|
||
static int apply_lock_personality(const ExecContext *c, const ExecParameters *p) {
|
||
unsigned long personality;
|
||
int r;
|
||
|
||
assert(c);
|
||
assert(p);
|
||
|
||
if (!c->lock_personality)
|
||
return 0;
|
||
|
||
if (skip_seccomp_unavailable(c, p, "LockPersonality="))
|
||
return 0;
|
||
|
||
personality = c->personality;
|
||
|
||
/* If personality is not specified, use either PER_LINUX or PER_LINUX32 depending on what is currently set. */
|
||
if (personality == PERSONALITY_INVALID) {
|
||
|
||
r = opinionated_personality(&personality);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
return seccomp_lock_personality(personality);
|
||
}
|
||
|
||
#endif
|
||
|
||
#if HAVE_LIBBPF
|
||
static int apply_restrict_filesystems(const ExecContext *c, const ExecParameters *p) {
|
||
int r;
|
||
|
||
assert(c);
|
||
assert(p);
|
||
|
||
if (!exec_context_restrict_filesystems_set(c))
|
||
return 0;
|
||
|
||
if (p->bpf_restrict_fs_map_fd < 0) {
|
||
/* LSM BPF is unsupported or lsm_bpf_setup failed */
|
||
log_exec_debug(c, p, "LSM BPF not supported, skipping RestrictFileSystems=");
|
||
return 0;
|
||
}
|
||
|
||
/* We are in a new binary, so dl-open again */
|
||
r = dlopen_bpf();
|
||
if (r < 0)
|
||
return r;
|
||
|
||
return bpf_restrict_fs_update(c->restrict_filesystems, p->cgroup_id, p->bpf_restrict_fs_map_fd, c->restrict_filesystems_allow_list);
|
||
}
|
||
#endif
|
||
|
||
static int apply_protect_hostname(const ExecContext *c, const ExecParameters *p, int *ret_exit_status) {
|
||
int r;
|
||
|
||
assert(c);
|
||
assert(p);
|
||
|
||
if (c->protect_hostname == PROTECT_HOSTNAME_NO)
|
||
return 0;
|
||
|
||
if (ns_type_supported(NAMESPACE_UTS)) {
|
||
if (unshare(CLONE_NEWUTS) < 0) {
|
||
if (!ERRNO_IS_NOT_SUPPORTED(errno) && !ERRNO_IS_PRIVILEGE(errno)) {
|
||
*ret_exit_status = EXIT_NAMESPACE;
|
||
return log_exec_error_errno(c, p, errno, "Failed to set up UTS namespacing: %m");
|
||
}
|
||
|
||
log_exec_warning(c, p,
|
||
"ProtectHostname=%s is configured, but UTS namespace setup is prohibited (container manager?), ignoring namespace setup.",
|
||
protect_hostname_to_string(c->protect_hostname));
|
||
|
||
} else if (c->private_hostname) {
|
||
r = sethostname_idempotent(c->private_hostname);
|
||
if (r < 0) {
|
||
*ret_exit_status = EXIT_NAMESPACE;
|
||
return log_exec_error_errno(c, p, r, "Failed to set private hostname '%s': %m", c->private_hostname);
|
||
}
|
||
}
|
||
} else
|
||
log_exec_warning(c, p,
|
||
"ProtectHostname=%s is configured, but the kernel does not support UTS namespaces, ignoring namespace setup.",
|
||
protect_hostname_to_string(c->protect_hostname));
|
||
|
||
#if HAVE_SECCOMP
|
||
if (c->protect_hostname == PROTECT_HOSTNAME_YES) {
|
||
if (skip_seccomp_unavailable(c, p, "ProtectHostname="))
|
||
return 0;
|
||
|
||
r = seccomp_protect_hostname();
|
||
if (r < 0) {
|
||
*ret_exit_status = EXIT_SECCOMP;
|
||
return log_exec_error_errno(c, p, r, "Failed to apply hostname restrictions: %m");
|
||
}
|
||
}
|
||
#endif
|
||
|
||
return 0;
|
||
}
|
||
|
||
static void do_idle_pipe_dance(int idle_pipe[static 4]) {
|
||
assert(idle_pipe);
|
||
|
||
idle_pipe[1] = safe_close(idle_pipe[1]);
|
||
idle_pipe[2] = safe_close(idle_pipe[2]);
|
||
|
||
if (idle_pipe[0] >= 0) {
|
||
int r;
|
||
|
||
r = fd_wait_for_event(idle_pipe[0], POLLHUP, IDLE_TIMEOUT_USEC);
|
||
|
||
if (idle_pipe[3] >= 0 && r == 0 /* timeout */) {
|
||
ssize_t n;
|
||
|
||
/* Signal systemd that we are bored and want to continue. */
|
||
n = write(idle_pipe[3], "x", 1);
|
||
if (n > 0)
|
||
/* Wait for systemd to react to the signal above. */
|
||
(void) fd_wait_for_event(idle_pipe[0], POLLHUP, IDLE_TIMEOUT2_USEC);
|
||
}
|
||
|
||
idle_pipe[0] = safe_close(idle_pipe[0]);
|
||
|
||
}
|
||
|
||
idle_pipe[3] = safe_close(idle_pipe[3]);
|
||
}
|
||
|
||
static const char *exec_directory_env_name_to_string(ExecDirectoryType t);
|
||
|
||
/* And this table also maps ExecDirectoryType, to the environment variable we pass the selected directory to
|
||
* the service payload in. */
|
||
static const char* const exec_directory_env_name_table[_EXEC_DIRECTORY_TYPE_MAX] = {
|
||
[EXEC_DIRECTORY_RUNTIME] = "RUNTIME_DIRECTORY",
|
||
[EXEC_DIRECTORY_STATE] = "STATE_DIRECTORY",
|
||
[EXEC_DIRECTORY_CACHE] = "CACHE_DIRECTORY",
|
||
[EXEC_DIRECTORY_LOGS] = "LOGS_DIRECTORY",
|
||
[EXEC_DIRECTORY_CONFIGURATION] = "CONFIGURATION_DIRECTORY",
|
||
};
|
||
|
||
DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(exec_directory_env_name, ExecDirectoryType);
|
||
|
||
static int build_environment(
|
||
const ExecContext *c,
|
||
const ExecParameters *p,
|
||
const CGroupContext *cgroup_context,
|
||
size_t n_fds,
|
||
const char *home,
|
||
const char *username,
|
||
const char *shell,
|
||
dev_t journal_stream_dev,
|
||
ino_t journal_stream_ino,
|
||
const char *memory_pressure_path,
|
||
bool needs_sandboxing,
|
||
char ***ret) {
|
||
|
||
_cleanup_strv_free_ char **our_env = NULL;
|
||
size_t n_env = 0;
|
||
char *x;
|
||
int r;
|
||
|
||
assert(c);
|
||
assert(p);
|
||
assert(ret);
|
||
|
||
#define N_ENV_VARS 20
|
||
our_env = new0(char*, N_ENV_VARS + _EXEC_DIRECTORY_TYPE_MAX);
|
||
if (!our_env)
|
||
return -ENOMEM;
|
||
|
||
if (n_fds > 0) {
|
||
_cleanup_free_ char *joined = NULL;
|
||
|
||
if (asprintf(&x, "LISTEN_PID="PID_FMT, getpid_cached()) < 0)
|
||
return -ENOMEM;
|
||
our_env[n_env++] = x;
|
||
|
||
if (asprintf(&x, "LISTEN_FDS=%zu", n_fds) < 0)
|
||
return -ENOMEM;
|
||
our_env[n_env++] = x;
|
||
|
||
joined = strv_join(p->fd_names, ":");
|
||
if (!joined)
|
||
return -ENOMEM;
|
||
|
||
x = strjoin("LISTEN_FDNAMES=", joined);
|
||
if (!x)
|
||
return -ENOMEM;
|
||
our_env[n_env++] = x;
|
||
}
|
||
|
||
if ((p->flags & EXEC_SET_WATCHDOG) && p->watchdog_usec > 0) {
|
||
if (asprintf(&x, "WATCHDOG_PID="PID_FMT, getpid_cached()) < 0)
|
||
return -ENOMEM;
|
||
our_env[n_env++] = x;
|
||
|
||
if (asprintf(&x, "WATCHDOG_USEC="USEC_FMT, p->watchdog_usec) < 0)
|
||
return -ENOMEM;
|
||
our_env[n_env++] = x;
|
||
}
|
||
|
||
/* If this is D-Bus, tell the nss-systemd module, since it relies on being able to use blocking
|
||
* Varlink calls back to us for look up dynamic users in PID 1. Break the deadlock between D-Bus and
|
||
* PID 1 by disabling use of PID1' NSS interface for looking up dynamic users. */
|
||
if (p->flags & EXEC_NSS_DYNAMIC_BYPASS) {
|
||
x = strdup("SYSTEMD_NSS_DYNAMIC_BYPASS=1");
|
||
if (!x)
|
||
return -ENOMEM;
|
||
our_env[n_env++] = x;
|
||
}
|
||
|
||
/* We query "root" if this is a system unit and User= is not specified. $USER is always set. $HOME
|
||
* could cause problem for e.g. getty, since login doesn't override $HOME, and $LOGNAME and $SHELL don't
|
||
* really make much sense since we're not logged in. Hence we conditionalize the three based on
|
||
* SetLoginEnvironment= switch. */
|
||
if (!c->user && !c->dynamic_user && p->runtime_scope == RUNTIME_SCOPE_SYSTEM) {
|
||
r = get_fixed_user("root", &username, NULL, NULL, &home, &shell);
|
||
if (r < 0)
|
||
return log_exec_debug_errno(c,
|
||
p,
|
||
r,
|
||
"Failed to determine user credentials for root: %m");
|
||
}
|
||
|
||
bool set_user_login_env = exec_context_get_set_login_environment(c);
|
||
|
||
if (username) {
|
||
x = strjoin("USER=", username);
|
||
if (!x)
|
||
return -ENOMEM;
|
||
our_env[n_env++] = x;
|
||
|
||
if (set_user_login_env) {
|
||
x = strjoin("LOGNAME=", username);
|
||
if (!x)
|
||
return -ENOMEM;
|
||
our_env[n_env++] = x;
|
||
}
|
||
}
|
||
|
||
/* Note that we don't set $HOME or $SHELL if they are not particularly enlightening anyway
|
||
* (i.e. are "/" or "/bin/nologin"). */
|
||
|
||
if (home && set_user_login_env && !empty_or_root(home)) {
|
||
x = strjoin("HOME=", home);
|
||
if (!x)
|
||
return -ENOMEM;
|
||
|
||
path_simplify(x + 5);
|
||
our_env[n_env++] = x;
|
||
}
|
||
|
||
if (shell && set_user_login_env && !shell_is_placeholder(shell)) {
|
||
x = strjoin("SHELL=", shell);
|
||
if (!x)
|
||
return -ENOMEM;
|
||
|
||
path_simplify(x + 6);
|
||
our_env[n_env++] = x;
|
||
}
|
||
|
||
if (!sd_id128_is_null(p->invocation_id)) {
|
||
assert(p->invocation_id_string);
|
||
|
||
x = strjoin("INVOCATION_ID=", p->invocation_id_string);
|
||
if (!x)
|
||
return -ENOMEM;
|
||
|
||
our_env[n_env++] = x;
|
||
}
|
||
|
||
if (exec_context_needs_term(c)) {
|
||
_cleanup_free_ char *cmdline = NULL;
|
||
const char *tty_path, *term = NULL;
|
||
|
||
tty_path = exec_context_tty_path(c);
|
||
|
||
/* If we are forked off PID 1 and we are supposed to operate on /dev/console, then let's try
|
||
* to inherit the $TERM set for PID 1. This is useful for containers so that the $TERM the
|
||
* container manager passes to PID 1 ends up all the way in the console login shown. */
|
||
|
||
if (path_equal(tty_path, "/dev/console") && getppid() == 1)
|
||
term = getenv("TERM");
|
||
else if (tty_path && in_charset(skip_dev_prefix(tty_path), ALPHANUMERICAL)) {
|
||
_cleanup_free_ char *key = NULL;
|
||
|
||
key = strjoin("systemd.tty.term.", skip_dev_prefix(tty_path));
|
||
if (!key)
|
||
return -ENOMEM;
|
||
|
||
r = proc_cmdline_get_key(key, 0, &cmdline);
|
||
if (r < 0)
|
||
log_exec_debug_errno(c,
|
||
p,
|
||
r,
|
||
"Failed to read %s from kernel cmdline, ignoring: %m",
|
||
key);
|
||
else if (r > 0)
|
||
term = cmdline;
|
||
}
|
||
|
||
if (!term)
|
||
term = default_term_for_tty(tty_path);
|
||
|
||
x = strjoin("TERM=", term);
|
||
if (!x)
|
||
return -ENOMEM;
|
||
our_env[n_env++] = x;
|
||
}
|
||
|
||
if (journal_stream_dev != 0 && journal_stream_ino != 0) {
|
||
if (asprintf(&x, "JOURNAL_STREAM=" DEV_FMT ":" INO_FMT, journal_stream_dev, journal_stream_ino) < 0)
|
||
return -ENOMEM;
|
||
|
||
our_env[n_env++] = x;
|
||
}
|
||
|
||
if (c->log_namespace) {
|
||
x = strjoin("LOG_NAMESPACE=", c->log_namespace);
|
||
if (!x)
|
||
return -ENOMEM;
|
||
|
||
our_env[n_env++] = x;
|
||
}
|
||
|
||
for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) {
|
||
_cleanup_free_ char *joined = NULL;
|
||
const char *n;
|
||
|
||
if (!p->prefix[t])
|
||
continue;
|
||
|
||
if (c->directories[t].n_items == 0)
|
||
continue;
|
||
|
||
n = exec_directory_env_name_to_string(t);
|
||
if (!n)
|
||
continue;
|
||
|
||
for (size_t i = 0; i < c->directories[t].n_items; i++) {
|
||
_cleanup_free_ char *prefixed = NULL;
|
||
|
||
prefixed = path_join(p->prefix[t], c->directories[t].items[i].path);
|
||
if (!prefixed)
|
||
return -ENOMEM;
|
||
|
||
if (!strextend_with_separator(&joined, ":", prefixed))
|
||
return -ENOMEM;
|
||
}
|
||
|
||
x = strjoin(n, "=", joined);
|
||
if (!x)
|
||
return -ENOMEM;
|
||
|
||
our_env[n_env++] = x;
|
||
}
|
||
|
||
_cleanup_free_ char *creds_dir = NULL;
|
||
r = exec_context_get_credential_directory(c, p, p->unit_id, &creds_dir);
|
||
if (r < 0)
|
||
return r;
|
||
if (r > 0) {
|
||
x = strjoin("CREDENTIALS_DIRECTORY=", creds_dir);
|
||
if (!x)
|
||
return -ENOMEM;
|
||
|
||
our_env[n_env++] = x;
|
||
}
|
||
|
||
if (asprintf(&x, "SYSTEMD_EXEC_PID=" PID_FMT, getpid_cached()) < 0)
|
||
return -ENOMEM;
|
||
|
||
our_env[n_env++] = x;
|
||
|
||
if (memory_pressure_path) {
|
||
x = strjoin("MEMORY_PRESSURE_WATCH=", memory_pressure_path);
|
||
if (!x)
|
||
return -ENOMEM;
|
||
|
||
our_env[n_env++] = x;
|
||
|
||
if (cgroup_context && !path_equal(memory_pressure_path, "/dev/null")) {
|
||
_cleanup_free_ char *b = NULL, *e = NULL;
|
||
|
||
if (asprintf(&b, "%s " USEC_FMT " " USEC_FMT,
|
||
MEMORY_PRESSURE_DEFAULT_TYPE,
|
||
cgroup_context->memory_pressure_threshold_usec == USEC_INFINITY ? MEMORY_PRESSURE_DEFAULT_THRESHOLD_USEC :
|
||
CLAMP(cgroup_context->memory_pressure_threshold_usec, 1U, MEMORY_PRESSURE_DEFAULT_WINDOW_USEC),
|
||
MEMORY_PRESSURE_DEFAULT_WINDOW_USEC) < 0)
|
||
return -ENOMEM;
|
||
|
||
if (base64mem(b, strlen(b) + 1, &e) < 0)
|
||
return -ENOMEM;
|
||
|
||
x = strjoin("MEMORY_PRESSURE_WRITE=", e);
|
||
if (!x)
|
||
return -ENOMEM;
|
||
|
||
our_env[n_env++] = x;
|
||
}
|
||
}
|
||
|
||
if (p->notify_socket) {
|
||
x = strjoin("NOTIFY_SOCKET=", exec_get_private_notify_socket_path(c, p, needs_sandboxing) ?: p->notify_socket);
|
||
if (!x)
|
||
return -ENOMEM;
|
||
|
||
our_env[n_env++] = x;
|
||
}
|
||
|
||
assert(n_env < N_ENV_VARS + _EXEC_DIRECTORY_TYPE_MAX);
|
||
#undef N_ENV_VARS
|
||
|
||
*ret = TAKE_PTR(our_env);
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int build_pass_environment(const ExecContext *c, char ***ret) {
|
||
_cleanup_strv_free_ char **pass_env = NULL;
|
||
size_t n_env = 0;
|
||
|
||
STRV_FOREACH(i, c->pass_environment) {
|
||
_cleanup_free_ char *x = NULL;
|
||
char *v;
|
||
|
||
v = getenv(*i);
|
||
if (!v)
|
||
continue;
|
||
x = strjoin(*i, "=", v);
|
||
if (!x)
|
||
return -ENOMEM;
|
||
|
||
if (!GREEDY_REALLOC(pass_env, n_env + 2))
|
||
return -ENOMEM;
|
||
|
||
pass_env[n_env++] = TAKE_PTR(x);
|
||
pass_env[n_env] = NULL;
|
||
}
|
||
|
||
*ret = TAKE_PTR(pass_env);
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int setup_private_users(PrivateUsers private_users, uid_t ouid, gid_t ogid, uid_t uid, gid_t gid, bool allow_setgroups) {
|
||
_cleanup_free_ char *uid_map = NULL, *gid_map = NULL;
|
||
_cleanup_close_pair_ int errno_pipe[2] = EBADF_PAIR;
|
||
_cleanup_close_ int unshare_ready_fd = -EBADF;
|
||
_cleanup_(sigkill_waitp) pid_t pid = 0;
|
||
uint64_t c = 1;
|
||
ssize_t n;
|
||
int r;
|
||
|
||
/* Set up a user namespace and map the original UID/GID (IDs from before any user or group changes, i.e.
|
||
* the IDs from the user or system manager(s)) to itself, the selected UID/GID to itself, and everything else to
|
||
* nobody. In order to be able to write this mapping we need CAP_SETUID in the original user namespace, which
|
||
* we however lack after opening the user namespace. To work around this we fork() a temporary child process,
|
||
* which waits for the parent to create the new user namespace while staying in the original namespace. The
|
||
* child then writes the UID mapping, under full privileges. The parent waits for the child to finish and
|
||
* continues execution normally.
|
||
* For unprivileged users (i.e. without capabilities), the root to root mapping is excluded. As such, it
|
||
* does not need CAP_SETUID to write the single line mapping to itself. */
|
||
|
||
if (private_users == PRIVATE_USERS_NO)
|
||
return 0;
|
||
|
||
if (private_users == PRIVATE_USERS_IDENTITY) {
|
||
uid_map = strdup("0 0 65536\n");
|
||
if (!uid_map)
|
||
return -ENOMEM;
|
||
} else if (private_users == PRIVATE_USERS_FULL) {
|
||
/* Map all UID/GID from original to new user namespace. We can't use `0 0 UINT32_MAX` because
|
||
* this is the same UID/GID map as the init user namespace and systemd's running_in_userns()
|
||
* checks whether its in a user namespace by comparing uid_map/gid_map to `0 0 UINT32_MAX`.
|
||
* Thus, we still map all UIDs/GIDs but do it using two extents to differentiate the new user
|
||
* namespace from the init namespace:
|
||
* 0 0 1
|
||
* 1 1 UINT32_MAX - 1
|
||
*
|
||
* systemd will remove the heuristic in running_in_userns() and use namespace inodes in version 258
|
||
* (PR #35382). But some users may be running a container image with older systemd < 258 so we keep
|
||
* this uid_map/gid_map hack until version 259 for version N-1 compatibility.
|
||
*
|
||
* TODO: Switch to `0 0 UINT32_MAX` in systemd v259.
|
||
*
|
||
* Note the kernel defines the UID range between 0 and UINT32_MAX so we map all UIDs even though
|
||
* the UID range beyond INT32_MAX (e.g. i.e. the range above the signed 32-bit range) is
|
||
* icky. For example, setfsuid() returns the old UID as signed integer. But units can decide to
|
||
* use these UIDs/GIDs so we need to map them. */
|
||
r = asprintf(&uid_map, "0 0 1\n"
|
||
"1 1 " UID_FMT "\n", (uid_t) (UINT32_MAX - 1));
|
||
if (r < 0)
|
||
return -ENOMEM;
|
||
/* Can only set up multiple mappings with CAP_SETUID. */
|
||
} else if (have_effective_cap(CAP_SETUID) > 0 && uid != ouid && uid_is_valid(uid)) {
|
||
r = asprintf(&uid_map,
|
||
UID_FMT " " UID_FMT " 1\n" /* Map $OUID → $OUID */
|
||
UID_FMT " " UID_FMT " 1\n", /* Map $UID → $UID */
|
||
ouid, ouid, uid, uid);
|
||
if (r < 0)
|
||
return -ENOMEM;
|
||
} else {
|
||
r = asprintf(&uid_map,
|
||
UID_FMT " " UID_FMT " 1\n", /* Map $OUID → $OUID */
|
||
ouid, ouid);
|
||
if (r < 0)
|
||
return -ENOMEM;
|
||
}
|
||
|
||
if (private_users == PRIVATE_USERS_IDENTITY) {
|
||
gid_map = strdup("0 0 65536\n");
|
||
if (!gid_map)
|
||
return -ENOMEM;
|
||
} else if (private_users == PRIVATE_USERS_FULL) {
|
||
r = asprintf(&gid_map, "0 0 1\n"
|
||
"1 1 " GID_FMT "\n", (gid_t) (UINT32_MAX - 1));
|
||
if (r < 0)
|
||
return -ENOMEM;
|
||
/* Can only set up multiple mappings with CAP_SETGID. */
|
||
} else if (have_effective_cap(CAP_SETGID) > 0 && gid != ogid && gid_is_valid(gid)) {
|
||
r = asprintf(&gid_map,
|
||
GID_FMT " " GID_FMT " 1\n" /* Map $OGID → $OGID */
|
||
GID_FMT " " GID_FMT " 1\n", /* Map $GID → $GID */
|
||
ogid, ogid, gid, gid);
|
||
if (r < 0)
|
||
return -ENOMEM;
|
||
} else {
|
||
r = asprintf(&gid_map,
|
||
GID_FMT " " GID_FMT " 1\n", /* Map $OGID -> $OGID */
|
||
ogid, ogid);
|
||
if (r < 0)
|
||
return -ENOMEM;
|
||
}
|
||
|
||
/* Create a communication channel so that the parent can tell the child when it finished creating the user
|
||
* namespace. */
|
||
unshare_ready_fd = eventfd(0, EFD_CLOEXEC);
|
||
if (unshare_ready_fd < 0)
|
||
return -errno;
|
||
|
||
/* Create a communication channel so that the child can tell the parent a proper error code in case it
|
||
* failed. */
|
||
if (pipe2(errno_pipe, O_CLOEXEC) < 0)
|
||
return -errno;
|
||
|
||
r = safe_fork("(sd-userns)", FORK_RESET_SIGNALS|FORK_DEATHSIG_SIGKILL, &pid);
|
||
if (r < 0)
|
||
return r;
|
||
if (r == 0) {
|
||
_cleanup_close_ int fd = -EBADF;
|
||
const char *a;
|
||
pid_t ppid;
|
||
|
||
/* Child process, running in the original user namespace. Let's update the parent's UID/GID map from
|
||
* here, after the parent opened its own user namespace. */
|
||
|
||
ppid = getppid();
|
||
errno_pipe[0] = safe_close(errno_pipe[0]);
|
||
|
||
/* Wait until the parent unshared the user namespace */
|
||
if (read(unshare_ready_fd, &c, sizeof(c)) < 0)
|
||
report_errno_and_exit(errno_pipe[1], -errno);
|
||
|
||
/* Disable the setgroups() system call in the child user namespace, for good, unless PrivateUsers=full
|
||
* and using the system service manager. */
|
||
a = procfs_file_alloca(ppid, "setgroups");
|
||
fd = open(a, O_WRONLY|O_CLOEXEC);
|
||
if (fd < 0) {
|
||
if (errno != ENOENT) {
|
||
r = log_debug_errno(errno, "Failed to open %s: %m", a);
|
||
report_errno_and_exit(errno_pipe[1], r);
|
||
}
|
||
|
||
/* If the file is missing the kernel is too old, let's continue anyway. */
|
||
} else {
|
||
const char *setgroups = allow_setgroups ? "allow\n" : "deny\n";
|
||
if (write(fd, setgroups, strlen(setgroups)) < 0) {
|
||
r = log_debug_errno(errno, "Failed to write '%s' to %s: %m", setgroups, a);
|
||
report_errno_and_exit(errno_pipe[1], r);
|
||
}
|
||
|
||
fd = safe_close(fd);
|
||
}
|
||
|
||
/* First write the GID map */
|
||
a = procfs_file_alloca(ppid, "gid_map");
|
||
fd = open(a, O_WRONLY|O_CLOEXEC);
|
||
if (fd < 0) {
|
||
r = log_debug_errno(errno, "Failed to open %s: %m", a);
|
||
report_errno_and_exit(errno_pipe[1], r);
|
||
}
|
||
|
||
if (write(fd, gid_map, strlen(gid_map)) < 0) {
|
||
r = log_debug_errno(errno, "Failed to write GID map to %s: %m", a);
|
||
report_errno_and_exit(errno_pipe[1], r);
|
||
}
|
||
|
||
fd = safe_close(fd);
|
||
|
||
/* The write the UID map */
|
||
a = procfs_file_alloca(ppid, "uid_map");
|
||
fd = open(a, O_WRONLY|O_CLOEXEC);
|
||
if (fd < 0) {
|
||
r = log_debug_errno(errno, "Failed to open %s: %m", a);
|
||
report_errno_and_exit(errno_pipe[1], r);
|
||
}
|
||
|
||
if (write(fd, uid_map, strlen(uid_map)) < 0) {
|
||
r = log_debug_errno(errno, "Failed to write UID map to %s: %m", a);
|
||
report_errno_and_exit(errno_pipe[1], r);
|
||
}
|
||
|
||
_exit(EXIT_SUCCESS);
|
||
}
|
||
|
||
errno_pipe[1] = safe_close(errno_pipe[1]);
|
||
|
||
if (unshare(CLONE_NEWUSER) < 0)
|
||
return log_debug_errno(errno, "Failed to unshare user namespace: %m");
|
||
|
||
/* Let the child know that the namespace is ready now */
|
||
if (write(unshare_ready_fd, &c, sizeof(c)) < 0)
|
||
return -errno;
|
||
|
||
/* Try to read an error code from the child */
|
||
n = read(errno_pipe[0], &r, sizeof(r));
|
||
if (n < 0)
|
||
return -errno;
|
||
if (n == sizeof(r)) { /* an error code was sent to us */
|
||
if (r < 0)
|
||
return r;
|
||
return -EIO;
|
||
}
|
||
if (n != 0) /* on success we should have read 0 bytes */
|
||
return -EIO;
|
||
|
||
r = wait_for_terminate_and_check("(sd-userns)", TAKE_PID(pid), 0);
|
||
if (r < 0)
|
||
return r;
|
||
if (r != EXIT_SUCCESS) /* If something strange happened with the child, let's consider this fatal, too */
|
||
return -EIO;
|
||
|
||
return 1;
|
||
}
|
||
|
||
static int can_mount_proc(const ExecContext *c, ExecParameters *p) {
|
||
_cleanup_close_pair_ int errno_pipe[2] = EBADF_PAIR;
|
||
_cleanup_(sigkill_waitp) pid_t pid = 0;
|
||
ssize_t n;
|
||
int r;
|
||
|
||
assert(c);
|
||
assert(p);
|
||
|
||
/* If running via unprivileged user manager and /proc/ is masked (e.g. /proc/kmsg is over-mounted with tmpfs
|
||
* like systemd-nspawn does), then mounting /proc/ will fail with EPERM. This is due to a kernel restriction
|
||
* where unprivileged user namespaces cannot mount a less restrictive instance of /proc. */
|
||
|
||
/* Create a communication channel so that the child can tell the parent a proper error code in case it
|
||
* failed. */
|
||
if (pipe2(errno_pipe, O_CLOEXEC) < 0)
|
||
return log_exec_debug_errno(c, p, errno, "Failed to create pipe for communicating with child process (sd-proc-check): %m");
|
||
|
||
/* Fork a child process into its own mount and PID namespace. Note safe_fork() already remounts / as SLAVE
|
||
* with FORK_MOUNTNS_SLAVE. */
|
||
r = safe_fork("(sd-proc-check)",
|
||
FORK_RESET_SIGNALS|FORK_DEATHSIG_SIGKILL|FORK_NEW_MOUNTNS|FORK_MOUNTNS_SLAVE|FORK_NEW_PIDNS, &pid);
|
||
if (r < 0)
|
||
return log_exec_debug_errno(c, p, r, "Failed to fork child process (sd-proc-check): %m");
|
||
if (r == 0) {
|
||
errno_pipe[0] = safe_close(errno_pipe[0]);
|
||
|
||
/* Try mounting /proc on /dev/shm/. No need to clean up the mount since the mount
|
||
* namespace will be cleaned up once the process exits. */
|
||
r = mount_follow_verbose(LOG_DEBUG, "proc", "/dev/shm/", "proc", MS_NOSUID|MS_NOEXEC|MS_NODEV, NULL);
|
||
if (r < 0) {
|
||
(void) write(errno_pipe[1], &r, sizeof(r));
|
||
_exit(EXIT_FAILURE);
|
||
}
|
||
|
||
_exit(EXIT_SUCCESS);
|
||
}
|
||
|
||
errno_pipe[1] = safe_close(errno_pipe[1]);
|
||
|
||
/* Try to read an error code from the child */
|
||
n = read(errno_pipe[0], &r, sizeof(r));
|
||
if (n < 0)
|
||
return log_exec_debug_errno(c, p, errno, "Failed to read errno from pipe with child process (sd-proc-check): %m");
|
||
if (n == sizeof(r)) { /* an error code was sent to us */
|
||
/* This is the expected case where proc cannot be mounted due to permissions. */
|
||
if (ERRNO_IS_NEG_PRIVILEGE(r))
|
||
return 0;
|
||
if (r < 0)
|
||
return r;
|
||
|
||
return -EIO;
|
||
}
|
||
if (n != 0) /* on success we should have read 0 bytes */
|
||
return -EIO;
|
||
|
||
r = wait_for_terminate_and_check("(sd-proc-check)", TAKE_PID(pid), 0 /* flags= */);
|
||
if (r < 0)
|
||
return log_exec_debug_errno(c, p, r, "Failed to wait for (sd-proc-check) child process to terminate: %m");
|
||
if (r != EXIT_SUCCESS) /* If something strange happened with the child, let's consider this fatal, too */
|
||
return log_exec_debug_errno(c, p, SYNTHETIC_ERRNO(EIO), "Child process (sd-proc-check) exited with unexpected exit status '%d'.", r);
|
||
|
||
return 1;
|
||
}
|
||
|
||
static int setup_private_pids(const ExecContext *c, ExecParameters *p) {
|
||
_cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
|
||
_cleanup_close_pair_ int errno_pipe[2] = EBADF_PAIR;
|
||
ssize_t n;
|
||
int r, q;
|
||
|
||
assert(c);
|
||
assert(p);
|
||
assert(p->pidref_transport_fd >= 0);
|
||
|
||
/* The first process created after unsharing a pid namespace becomes PID 1 in the pid namespace, so
|
||
* we have to fork after unsharing the pid namespace to become PID 1. The parent sends the child
|
||
* pidref to the manager and exits while the child process continues with the rest of exec_invoke()
|
||
* and finally executes the actual payload. */
|
||
|
||
/* Create a communication channel so that the parent can tell the child a proper error code in case it
|
||
* failed to send child pidref to the manager. */
|
||
if (pipe2(errno_pipe, O_CLOEXEC) < 0)
|
||
return log_exec_debug_errno(c, p, errno, "Failed to create pipe for communicating with parent process: %m");
|
||
|
||
r = pidref_safe_fork("(sd-pidns-child)", FORK_NEW_PIDNS, &pidref);
|
||
if (r < 0)
|
||
return log_exec_debug_errno(c, p, r, "Failed to fork child into new pid namespace: %m");
|
||
if (r > 0) {
|
||
errno_pipe[0] = safe_close(errno_pipe[0]);
|
||
|
||
/* In the parent process, we send the child pidref to the manager and exit.
|
||
* If PIDFD is not supported, only the child PID is sent. The server then
|
||
* uses the child PID to set the new exec main process. */
|
||
q = send_one_fd_iov(
|
||
p->pidref_transport_fd,
|
||
pidref.fd,
|
||
&IOVEC_MAKE(&pidref.pid, sizeof(pidref.pid)),
|
||
/*iovlen=*/ 1,
|
||
/*flags=*/ 0);
|
||
/* Send error code to child process. */
|
||
(void) write(errno_pipe[1], &q, sizeof(q));
|
||
/* Exit here so we only go through the destructors in exec_invoke only once - in the child - as
|
||
* some destructors have external effects. The main codepaths continue in the child process. */
|
||
_exit(q < 0 ? EXIT_FAILURE : EXIT_SUCCESS);
|
||
}
|
||
|
||
errno_pipe[1] = safe_close(errno_pipe[1]);
|
||
p->pidref_transport_fd = safe_close(p->pidref_transport_fd);
|
||
|
||
/* Try to read an error code from the parent. Note a child process cannot wait for the parent so we always
|
||
* receive an errno even on success. */
|
||
n = read(errno_pipe[0], &r, sizeof(r));
|
||
if (n < 0)
|
||
return log_exec_debug_errno(c, p, errno, "Failed to read errno from pipe with parent process: %m");
|
||
if (n != sizeof(r))
|
||
return log_exec_debug_errno(c, p, SYNTHETIC_ERRNO(EIO), "Failed to read enough bytes from pipe with parent process");
|
||
if (r < 0)
|
||
return log_exec_debug_errno(c, p, r, "Failed to send child pidref to manager: %m");
|
||
|
||
/* NOTE! This function returns in the child process only. */
|
||
return r;
|
||
}
|
||
|
||
static int create_many_symlinks(const char *root, const char *source, char **symlinks) {
|
||
_cleanup_free_ char *src_abs = NULL;
|
||
int r;
|
||
|
||
assert(source);
|
||
|
||
src_abs = path_join(root, source);
|
||
if (!src_abs)
|
||
return -ENOMEM;
|
||
|
||
STRV_FOREACH(dst, symlinks) {
|
||
_cleanup_free_ char *dst_abs = NULL;
|
||
|
||
dst_abs = path_join(root, *dst);
|
||
if (!dst_abs)
|
||
return -ENOMEM;
|
||
|
||
r = mkdir_parents_label(dst_abs, 0755);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
r = symlink_idempotent(src_abs, dst_abs, true);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int setup_exec_directory(
|
||
const ExecContext *context,
|
||
const ExecParameters *params,
|
||
uid_t uid,
|
||
gid_t gid,
|
||
ExecDirectoryType type,
|
||
bool needs_mount_namespace,
|
||
int *exit_status) {
|
||
|
||
static const int exit_status_table[_EXEC_DIRECTORY_TYPE_MAX] = {
|
||
[EXEC_DIRECTORY_RUNTIME] = EXIT_RUNTIME_DIRECTORY,
|
||
[EXEC_DIRECTORY_STATE] = EXIT_STATE_DIRECTORY,
|
||
[EXEC_DIRECTORY_CACHE] = EXIT_CACHE_DIRECTORY,
|
||
[EXEC_DIRECTORY_LOGS] = EXIT_LOGS_DIRECTORY,
|
||
[EXEC_DIRECTORY_CONFIGURATION] = EXIT_CONFIGURATION_DIRECTORY,
|
||
};
|
||
int r;
|
||
|
||
assert(context);
|
||
assert(params);
|
||
assert(type >= 0 && type < _EXEC_DIRECTORY_TYPE_MAX);
|
||
assert(exit_status);
|
||
|
||
if (!params->prefix[type])
|
||
return 0;
|
||
|
||
if (params->flags & EXEC_CHOWN_DIRECTORIES) {
|
||
if (!uid_is_valid(uid))
|
||
uid = 0;
|
||
if (!gid_is_valid(gid))
|
||
gid = 0;
|
||
}
|
||
|
||
FOREACH_ARRAY(i, context->directories[type].items, context->directories[type].n_items) {
|
||
_cleanup_free_ char *p = NULL, *pp = NULL;
|
||
|
||
p = path_join(params->prefix[type], i->path);
|
||
if (!p) {
|
||
r = -ENOMEM;
|
||
goto fail;
|
||
}
|
||
|
||
r = mkdir_parents_label(p, 0755);
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
if (IN_SET(type, EXEC_DIRECTORY_STATE, EXEC_DIRECTORY_LOGS) && params->runtime_scope == RUNTIME_SCOPE_USER) {
|
||
|
||
/* If we are in user mode, and a configuration directory exists but a state directory
|
||
* doesn't exist, then we likely are upgrading from an older systemd version that
|
||
* didn't know the more recent addition to the xdg-basedir spec: the $XDG_STATE_HOME
|
||
* directory. In older systemd versions EXEC_DIRECTORY_STATE was aliased to
|
||
* EXEC_DIRECTORY_CONFIGURATION, with the advent of $XDG_STATE_HOME it is now
|
||
* separated. If a service has both dirs configured but only the configuration dir
|
||
* exists and the state dir does not, we assume we are looking at an update
|
||
* situation. Hence, create a compatibility symlink, so that all expectations are
|
||
* met.
|
||
*
|
||
* (We also do something similar with the log directory, which still doesn't exist in
|
||
* the xdg basedir spec. We'll make it a subdir of the state dir.) */
|
||
|
||
/* this assumes the state dir is always created before the configuration dir */
|
||
assert_cc(EXEC_DIRECTORY_STATE < EXEC_DIRECTORY_LOGS);
|
||
assert_cc(EXEC_DIRECTORY_LOGS < EXEC_DIRECTORY_CONFIGURATION);
|
||
|
||
r = access_nofollow(p, F_OK);
|
||
if (r == -ENOENT) {
|
||
_cleanup_free_ char *q = NULL;
|
||
|
||
/* OK, we know that the state dir does not exist. Let's see if the dir exists
|
||
* under the configuration hierarchy. */
|
||
|
||
if (type == EXEC_DIRECTORY_STATE)
|
||
q = path_join(params->prefix[EXEC_DIRECTORY_CONFIGURATION], i->path);
|
||
else if (type == EXEC_DIRECTORY_LOGS)
|
||
q = path_join(params->prefix[EXEC_DIRECTORY_CONFIGURATION], "log", i->path);
|
||
else
|
||
assert_not_reached();
|
||
if (!q) {
|
||
r = -ENOMEM;
|
||
goto fail;
|
||
}
|
||
|
||
r = access_nofollow(q, F_OK);
|
||
if (r >= 0) {
|
||
/* It does exist! This hence looks like an update. Symlink the
|
||
* configuration directory into the state directory. */
|
||
|
||
r = symlink_idempotent(q, p, /* make_relative= */ true);
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
log_exec_notice(context, params, "Unit state directory %s missing but matching configuration directory %s exists, assuming update from systemd 253 or older, creating compatibility symlink.", p, q);
|
||
continue;
|
||
} else if (r != -ENOENT)
|
||
log_exec_warning_errno(context, params, r, "Unable to detect whether unit configuration directory '%s' exists, assuming not: %m", q);
|
||
|
||
} else if (r < 0)
|
||
log_exec_warning_errno(context, params, r, "Unable to detect whether unit state directory '%s' is missing, assuming it is: %m", p);
|
||
}
|
||
|
||
if (exec_directory_is_private(context, type)) {
|
||
/* So, here's one extra complication when dealing with DynamicUser=1 units. In that
|
||
* case we want to avoid leaving a directory around fully accessible that is owned by
|
||
* a dynamic user whose UID is later on reused. To lock this down we use the same
|
||
* trick used by container managers to prohibit host users to get access to files of
|
||
* the same UID in containers: we place everything inside a directory that has an
|
||
* access mode of 0700 and is owned root:root, so that it acts as security boundary
|
||
* for unprivileged host code. We then use fs namespacing to make this directory
|
||
* permeable for the service itself.
|
||
*
|
||
* Specifically: for a service which wants a special directory "foo/" we first create
|
||
* a directory "private/" with access mode 0700 owned by root:root. Then we place
|
||
* "foo" inside of that directory (i.e. "private/foo/"), and make "foo" a symlink to
|
||
* "private/foo". This way, privileged host users can access "foo/" as usual, but
|
||
* unprivileged host users can't look into it. Inside of the namespace of the unit
|
||
* "private/" is replaced by a more liberally accessible tmpfs, into which the host's
|
||
* "private/foo/" is mounted under the same name, thus disabling the access boundary
|
||
* for the service and making sure it only gets access to the dirs it needs but no
|
||
* others. Tricky? Yes, absolutely, but it works!
|
||
*
|
||
* Note that we don't do this for EXEC_DIRECTORY_CONFIGURATION as that's assumed not
|
||
* to be owned by the service itself.
|
||
*
|
||
* Also, note that we don't do this for EXEC_DIRECTORY_RUNTIME as that's often used
|
||
* for sharing files or sockets with other services. */
|
||
|
||
pp = path_join(params->prefix[type], "private");
|
||
if (!pp) {
|
||
r = -ENOMEM;
|
||
goto fail;
|
||
}
|
||
|
||
/* First set up private root if it doesn't exist yet, with access mode 0700 and owned by root:root */
|
||
r = mkdir_safe_label(pp, 0700, 0, 0, MKDIR_WARN_MODE);
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
if (!path_extend(&pp, i->path)) {
|
||
r = -ENOMEM;
|
||
goto fail;
|
||
}
|
||
|
||
/* Create all directories between the configured directory and this private root, and mark them 0755 */
|
||
r = mkdir_parents_label(pp, 0755);
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
if (is_dir(p, false) > 0 &&
|
||
(access_nofollow(pp, F_OK) == -ENOENT)) {
|
||
|
||
/* Hmm, the private directory doesn't exist yet, but the normal one exists? If so, move
|
||
* it over. Most likely the service has been upgraded from one that didn't use
|
||
* DynamicUser=1, to one that does. */
|
||
|
||
log_exec_info(context,
|
||
params,
|
||
"Found pre-existing public %s= directory %s, migrating to %s.\n"
|
||
"Apparently, service previously had DynamicUser= turned off, and has now turned it on.",
|
||
exec_directory_type_to_string(type), p, pp);
|
||
|
||
r = RET_NERRNO(rename(p, pp));
|
||
if (r < 0)
|
||
goto fail;
|
||
} else {
|
||
/* Otherwise, create the actual directory for the service */
|
||
|
||
r = mkdir_label(pp, context->directories[type].mode);
|
||
if (r < 0 && r != -EEXIST)
|
||
goto fail;
|
||
}
|
||
|
||
if (!FLAGS_SET(i->flags, EXEC_DIRECTORY_ONLY_CREATE)) {
|
||
/* And link it up from the original place.
|
||
* Notes
|
||
* 1) If a mount namespace is going to be used, then this symlink remains on
|
||
* the host, and a new one for the child namespace will be created later.
|
||
* 2) It is not necessary to create this symlink when one of its parent
|
||
* directories is specified and already created. E.g.
|
||
* StateDirectory=foo foo/bar
|
||
* In that case, the inode points to pp and p for "foo/bar" are the same:
|
||
* pp = "/var/lib/private/foo/bar"
|
||
* p = "/var/lib/foo/bar"
|
||
* and, /var/lib/foo is a symlink to /var/lib/private/foo. So, not only
|
||
* we do not need to create the symlink, but we cannot create the symlink.
|
||
* See issue #24783. */
|
||
r = symlink_idempotent(pp, p, true);
|
||
if (r < 0)
|
||
goto fail;
|
||
}
|
||
|
||
} else {
|
||
_cleanup_free_ char *target = NULL;
|
||
|
||
if (EXEC_DIRECTORY_TYPE_SHALL_CHOWN(type) &&
|
||
readlink_and_make_absolute(p, &target) >= 0) {
|
||
_cleanup_free_ char *q = NULL, *q_resolved = NULL, *target_resolved = NULL;
|
||
|
||
/* This already exists and is a symlink? Interesting. Maybe it's one created
|
||
* by DynamicUser=1 (see above)?
|
||
*
|
||
* We do this for all directory types except for ConfigurationDirectory=,
|
||
* since they all support the private/ symlink logic at least in some
|
||
* configurations, see above. */
|
||
|
||
r = chase(target, NULL, 0, &target_resolved, NULL);
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
q = path_join(params->prefix[type], "private", i->path);
|
||
if (!q) {
|
||
r = -ENOMEM;
|
||
goto fail;
|
||
}
|
||
|
||
/* /var/lib or friends may be symlinks. So, let's chase them also. */
|
||
r = chase(q, NULL, CHASE_NONEXISTENT, &q_resolved, NULL);
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
if (path_equal(q_resolved, target_resolved)) {
|
||
|
||
/* Hmm, apparently DynamicUser= was once turned on for this service,
|
||
* but is no longer. Let's move the directory back up. */
|
||
|
||
log_exec_info(context,
|
||
params,
|
||
"Found pre-existing private %s= directory %s, migrating to %s.\n"
|
||
"Apparently, service previously had DynamicUser= turned on, and has now turned it off.",
|
||
exec_directory_type_to_string(type), q, p);
|
||
|
||
r = RET_NERRNO(unlink(p));
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
r = RET_NERRNO(rename(q, p));
|
||
if (r < 0)
|
||
goto fail;
|
||
}
|
||
}
|
||
|
||
r = mkdir_label(p, context->directories[type].mode);
|
||
if (r < 0) {
|
||
if (r != -EEXIST)
|
||
goto fail;
|
||
|
||
if (!EXEC_DIRECTORY_TYPE_SHALL_CHOWN(type)) {
|
||
struct stat st;
|
||
|
||
/* Don't change the owner/access mode of the configuration directory,
|
||
* as in the common case it is not written to by a service, and shall
|
||
* not be writable. */
|
||
|
||
r = RET_NERRNO(stat(p, &st));
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
/* Still complain if the access mode doesn't match */
|
||
if (((st.st_mode ^ context->directories[type].mode) & 07777) != 0)
|
||
log_exec_warning(context,
|
||
params,
|
||
"%s \'%s\' already exists but the mode is different. "
|
||
"(File system: %o %sMode: %o)",
|
||
exec_directory_type_to_string(type), i->path,
|
||
st.st_mode & 07777, exec_directory_type_to_string(type), context->directories[type].mode & 07777);
|
||
|
||
continue;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Lock down the access mode (we use chmod_and_chown() to make this idempotent. We don't
|
||
* specify UID/GID here, so that path_chown_recursive() can optimize things depending on the
|
||
* current UID/GID ownership.) */
|
||
const char *target_dir = pp ?: p;
|
||
r = chmod_and_chown(target_dir, context->directories[type].mode, UID_INVALID, GID_INVALID);
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
/* Skip the rest (which deals with ownership) in user mode, since ownership changes are not
|
||
* available to user code anyway */
|
||
if (params->runtime_scope != RUNTIME_SCOPE_SYSTEM)
|
||
continue;
|
||
|
||
int idmapping_supported = is_idmapping_supported(target_dir);
|
||
if (idmapping_supported < 0) {
|
||
r = log_debug_errno(idmapping_supported, "Unable to determine if ID mapping is supported on mount '%s': %m", target_dir);
|
||
goto fail;
|
||
}
|
||
|
||
log_debug("ID-mapping is%ssupported for exec directory %s", idmapping_supported ? " " : " not ", target_dir);
|
||
|
||
/* Change the ownership of the whole tree, if necessary. When dynamic users are used we
|
||
* drop the suid/sgid bits, since we really don't want SUID/SGID files for dynamic UID/GID
|
||
* assignments to exist. */
|
||
uid_t chown_uid = uid;
|
||
gid_t chown_gid = gid;
|
||
bool do_chown = false;
|
||
|
||
if (uid == 0 || gid == 0 || !idmapping_supported) {
|
||
do_chown = true;
|
||
i->idmapped = false;
|
||
} else {
|
||
/* Use 'nobody' uid/gid for exec directories if ID-mapping is supported. For backward compatibility,
|
||
* continue doing chmod/chown if the directory was chmod/chowned before (if uid/gid is not 'nobody') */
|
||
struct stat st;
|
||
r = RET_NERRNO(stat(target_dir, &st));
|
||
if (r < 0)
|
||
goto fail;
|
||
|
||
if (st.st_uid == UID_NOBODY && st.st_gid == GID_NOBODY) {
|
||
do_chown = false;
|
||
i->idmapped = true;
|
||
} else if (exec_directory_is_private(context, type) && st.st_uid == 0 && st.st_gid == 0) {
|
||
chown_uid = UID_NOBODY;
|
||
chown_gid = GID_NOBODY;
|
||
do_chown = true;
|
||
i->idmapped = true;
|
||
} else {
|
||
do_chown = true;
|
||
i->idmapped = false;
|
||
}
|
||
}
|
||
|
||
if (do_chown) {
|
||
r = path_chown_recursive(target_dir, chown_uid, chown_gid, context->dynamic_user ? 01777 : 07777, AT_SYMLINK_FOLLOW);
|
||
if (r < 0)
|
||
goto fail;
|
||
}
|
||
}
|
||
|
||
/* If we are not going to run in a namespace, set up the symlinks - otherwise
|
||
* they are set up later, to allow configuring empty var/run/etc. */
|
||
if (!needs_mount_namespace)
|
||
FOREACH_ARRAY(i, context->directories[type].items, context->directories[type].n_items) {
|
||
r = create_many_symlinks(params->prefix[type], i->path, i->symlinks);
|
||
if (r < 0)
|
||
goto fail;
|
||
}
|
||
|
||
return 0;
|
||
|
||
fail:
|
||
*exit_status = exit_status_table[type];
|
||
return r;
|
||
}
|
||
|
||
#if ENABLE_SMACK
|
||
static int setup_smack(
|
||
const ExecParameters *params,
|
||
const ExecContext *context,
|
||
int executable_fd) {
|
||
int r;
|
||
|
||
assert(params);
|
||
assert(executable_fd >= 0);
|
||
|
||
if (context->smack_process_label) {
|
||
r = mac_smack_apply_pid(0, context->smack_process_label);
|
||
if (r < 0)
|
||
return r;
|
||
} else if (params->fallback_smack_process_label) {
|
||
_cleanup_free_ char *exec_label = NULL;
|
||
|
||
r = mac_smack_read_fd(executable_fd, SMACK_ATTR_EXEC, &exec_label);
|
||
if (r < 0 && !ERRNO_IS_XATTR_ABSENT(r))
|
||
return r;
|
||
|
||
r = mac_smack_apply_pid(0, exec_label ?: params->fallback_smack_process_label);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
#endif
|
||
|
||
static int compile_bind_mounts(
|
||
const ExecContext *context,
|
||
const ExecParameters *params,
|
||
uid_t exec_directory_uid, /* only used for id-mapped mounts Exec directories */
|
||
gid_t exec_directory_gid, /* only used for id-mapped mounts Exec directories */
|
||
BindMount **ret_bind_mounts,
|
||
size_t *ret_n_bind_mounts,
|
||
char ***ret_empty_directories) {
|
||
|
||
_cleanup_strv_free_ char **empty_directories = NULL;
|
||
BindMount *bind_mounts = NULL;
|
||
size_t n, h = 0;
|
||
int r;
|
||
|
||
assert(context);
|
||
assert(params);
|
||
assert(ret_bind_mounts);
|
||
assert(ret_n_bind_mounts);
|
||
assert(ret_empty_directories);
|
||
|
||
CLEANUP_ARRAY(bind_mounts, h, bind_mount_free_many);
|
||
|
||
n = context->n_bind_mounts;
|
||
for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) {
|
||
if (!params->prefix[t])
|
||
continue;
|
||
|
||
FOREACH_ARRAY(i, context->directories[t].items, context->directories[t].n_items)
|
||
n += !FLAGS_SET(i->flags, EXEC_DIRECTORY_ONLY_CREATE) || FLAGS_SET(i->flags, EXEC_DIRECTORY_READ_ONLY);
|
||
}
|
||
|
||
if (n <= 0) {
|
||
*ret_bind_mounts = NULL;
|
||
*ret_n_bind_mounts = 0;
|
||
*ret_empty_directories = NULL;
|
||
return 0;
|
||
}
|
||
|
||
bind_mounts = new(BindMount, n);
|
||
if (!bind_mounts)
|
||
return -ENOMEM;
|
||
|
||
FOREACH_ARRAY(item, context->bind_mounts, context->n_bind_mounts) {
|
||
r = bind_mount_add(&bind_mounts, &h, item);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) {
|
||
if (!params->prefix[t])
|
||
continue;
|
||
|
||
if (context->directories[t].n_items == 0)
|
||
continue;
|
||
|
||
if (exec_directory_is_private(context, t) &&
|
||
!exec_context_with_rootfs(context)) {
|
||
char *private_root;
|
||
|
||
/* So this is for a dynamic user, and we need to make sure the process can access its own
|
||
* directory. For that we overmount the usually inaccessible "private" subdirectory with a
|
||
* tmpfs that makes it accessible and is empty except for the submounts we do this for. */
|
||
|
||
private_root = path_join(params->prefix[t], "private");
|
||
if (!private_root)
|
||
return -ENOMEM;
|
||
|
||
r = strv_consume(&empty_directories, private_root);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
FOREACH_ARRAY(i, context->directories[t].items, context->directories[t].n_items) {
|
||
_cleanup_free_ char *s = NULL, *d = NULL;
|
||
|
||
/* When one of the parent directories is in the list, we cannot create the symlink
|
||
* for the child directory. See also the comments in setup_exec_directory().
|
||
* But if it needs to be read only, then we have to create a bind mount anyway to
|
||
* make it so. */
|
||
if (FLAGS_SET(i->flags, EXEC_DIRECTORY_ONLY_CREATE) && !FLAGS_SET(i->flags, EXEC_DIRECTORY_READ_ONLY))
|
||
continue;
|
||
|
||
if (exec_directory_is_private(context, t))
|
||
s = path_join(params->prefix[t], "private", i->path);
|
||
else
|
||
s = path_join(params->prefix[t], i->path);
|
||
if (!s)
|
||
return -ENOMEM;
|
||
|
||
if (exec_directory_is_private(context, t) &&
|
||
exec_context_with_rootfs(context))
|
||
/* When RootDirectory= or RootImage= are set, then the symbolic link to the private
|
||
* directory is not created on the root directory. So, let's bind-mount the directory
|
||
* on the 'non-private' place. */
|
||
d = path_join(params->prefix[t], i->path);
|
||
else
|
||
d = strdup(s);
|
||
if (!d)
|
||
return -ENOMEM;
|
||
|
||
bind_mounts[h++] = (BindMount) {
|
||
.source = TAKE_PTR(s),
|
||
.destination = TAKE_PTR(d),
|
||
.nosuid = context->dynamic_user, /* don't allow suid/sgid when DynamicUser= is on */
|
||
.recursive = true,
|
||
.read_only = FLAGS_SET(i->flags, EXEC_DIRECTORY_READ_ONLY),
|
||
.idmapped = i->idmapped,
|
||
.uid = exec_directory_uid,
|
||
.gid = exec_directory_gid,
|
||
};
|
||
}
|
||
}
|
||
|
||
assert(h == n);
|
||
|
||
*ret_bind_mounts = TAKE_PTR(bind_mounts);
|
||
*ret_n_bind_mounts = n;
|
||
*ret_empty_directories = TAKE_PTR(empty_directories);
|
||
|
||
return (int) n;
|
||
}
|
||
|
||
/* ret_symlinks will contain a list of pairs src:dest that describes
|
||
* the symlinks to create later on. For example, the symlinks needed
|
||
* to safely give private directories to DynamicUser=1 users. */
|
||
static int compile_symlinks(
|
||
const ExecContext *context,
|
||
const ExecParameters *params,
|
||
bool setup_os_release_symlink,
|
||
char ***ret_symlinks) {
|
||
|
||
_cleanup_strv_free_ char **symlinks = NULL;
|
||
int r;
|
||
|
||
assert(context);
|
||
assert(params);
|
||
assert(ret_symlinks);
|
||
|
||
for (ExecDirectoryType dt = 0; dt < _EXEC_DIRECTORY_TYPE_MAX; dt++)
|
||
FOREACH_ARRAY(i, context->directories[dt].items, context->directories[dt].n_items) {
|
||
_cleanup_free_ char *private_path = NULL, *path = NULL;
|
||
|
||
STRV_FOREACH(symlink, i->symlinks) {
|
||
_cleanup_free_ char *src_abs = NULL, *dst_abs = NULL;
|
||
|
||
src_abs = path_join(params->prefix[dt], i->path);
|
||
dst_abs = path_join(params->prefix[dt], *symlink);
|
||
if (!src_abs || !dst_abs)
|
||
return -ENOMEM;
|
||
|
||
r = strv_consume_pair(&symlinks, TAKE_PTR(src_abs), TAKE_PTR(dst_abs));
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
if (!exec_directory_is_private(context, dt) ||
|
||
exec_context_with_rootfs(context) ||
|
||
FLAGS_SET(i->flags, EXEC_DIRECTORY_ONLY_CREATE))
|
||
continue;
|
||
|
||
private_path = path_join(params->prefix[dt], "private", i->path);
|
||
if (!private_path)
|
||
return -ENOMEM;
|
||
|
||
path = path_join(params->prefix[dt], i->path);
|
||
if (!path)
|
||
return -ENOMEM;
|
||
|
||
r = strv_consume_pair(&symlinks, TAKE_PTR(private_path), TAKE_PTR(path));
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
/* We make the host's os-release available via a symlink, so that we can copy it atomically
|
||
* and readers will never get a half-written version. Note that, while the paths specified here are
|
||
* absolute, when they are processed in namespace.c they will be made relative automatically, i.e.:
|
||
* 'os-release -> .os-release-stage/os-release' is what will be created. */
|
||
if (setup_os_release_symlink) {
|
||
r = strv_extend_many(
|
||
&symlinks,
|
||
"/run/host/.os-release-stage/os-release",
|
||
"/run/host/os-release");
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
*ret_symlinks = TAKE_PTR(symlinks);
|
||
|
||
return 0;
|
||
}
|
||
|
||
static bool insist_on_sandboxing(
|
||
const ExecContext *context,
|
||
const char *root_dir,
|
||
const char *root_image,
|
||
const BindMount *bind_mounts,
|
||
size_t n_bind_mounts) {
|
||
|
||
assert(context);
|
||
assert(n_bind_mounts == 0 || bind_mounts);
|
||
|
||
/* Checks whether we need to insist on fs namespacing. i.e. whether we have settings configured that
|
||
* would alter the view on the file system beyond making things read-only or invisible, i.e. would
|
||
* rearrange stuff in a way we cannot ignore gracefully. */
|
||
|
||
if (context->n_temporary_filesystems > 0)
|
||
return true;
|
||
|
||
if (root_dir || root_image)
|
||
return true;
|
||
|
||
if (context->n_mount_images > 0)
|
||
return true;
|
||
|
||
if (context->dynamic_user)
|
||
return true;
|
||
|
||
if (context->n_extension_images > 0 || !strv_isempty(context->extension_directories))
|
||
return true;
|
||
|
||
/* If there are any bind mounts set that don't map back onto themselves, fs namespacing becomes
|
||
* essential. */
|
||
FOREACH_ARRAY(i, bind_mounts, n_bind_mounts)
|
||
if (!path_equal(i->source, i->destination))
|
||
return true;
|
||
|
||
if (context->log_namespace)
|
||
return true;
|
||
|
||
return false;
|
||
}
|
||
|
||
static int setup_ephemeral(
|
||
const ExecContext *context,
|
||
ExecRuntime *runtime,
|
||
char **root_image, /* both input and output! modified if ephemeral logic enabled */
|
||
char **root_directory, /* ditto */
|
||
char **reterr_path) {
|
||
|
||
_cleanup_close_ int fd = -EBADF;
|
||
_cleanup_free_ char *new_root = NULL;
|
||
int r;
|
||
|
||
assert(context);
|
||
assert(root_image);
|
||
assert(root_directory);
|
||
|
||
if (!*root_image && !*root_directory)
|
||
return 0;
|
||
|
||
if (!runtime || !runtime->ephemeral_copy)
|
||
return 0;
|
||
|
||
assert(runtime->ephemeral_storage_socket[0] >= 0);
|
||
assert(runtime->ephemeral_storage_socket[1] >= 0);
|
||
|
||
new_root = strdup(runtime->ephemeral_copy);
|
||
if (!new_root)
|
||
return log_oom_debug();
|
||
|
||
r = posix_lock(runtime->ephemeral_storage_socket[0], LOCK_EX);
|
||
if (r < 0)
|
||
return log_debug_errno(r, "Failed to lock ephemeral storage socket: %m");
|
||
|
||
CLEANUP_POSIX_UNLOCK(runtime->ephemeral_storage_socket[0]);
|
||
|
||
fd = receive_one_fd(runtime->ephemeral_storage_socket[0], MSG_PEEK|MSG_DONTWAIT);
|
||
if (fd >= 0)
|
||
/* We got an fd! That means ephemeral has already been set up, so nothing to do here. */
|
||
return 0;
|
||
if (fd != -EAGAIN)
|
||
return log_debug_errno(fd, "Failed to receive file descriptor queued on ephemeral storage socket: %m");
|
||
|
||
if (*root_image) {
|
||
log_debug("Making ephemeral copy of %s to %s", *root_image, new_root);
|
||
|
||
fd = copy_file(*root_image, new_root, O_EXCL, 0600,
|
||
COPY_LOCK_BSD|COPY_REFLINK|COPY_CRTIME|COPY_NOCOW_AFTER);
|
||
if (fd < 0) {
|
||
*reterr_path = strdup(*root_image);
|
||
return log_debug_errno(fd, "Failed to copy image %s to %s: %m",
|
||
*root_image, new_root);
|
||
}
|
||
} else {
|
||
assert(*root_directory);
|
||
|
||
log_debug("Making ephemeral snapshot of %s to %s", *root_directory, new_root);
|
||
|
||
fd = btrfs_subvol_snapshot_at(
|
||
AT_FDCWD, *root_directory,
|
||
AT_FDCWD, new_root,
|
||
BTRFS_SNAPSHOT_FALLBACK_COPY |
|
||
BTRFS_SNAPSHOT_FALLBACK_DIRECTORY |
|
||
BTRFS_SNAPSHOT_RECURSIVE |
|
||
BTRFS_SNAPSHOT_LOCK_BSD);
|
||
if (fd < 0) {
|
||
*reterr_path = strdup(*root_directory);
|
||
return log_debug_errno(fd, "Failed to snapshot directory %s to %s: %m",
|
||
*root_directory, new_root);
|
||
}
|
||
}
|
||
|
||
r = send_one_fd(runtime->ephemeral_storage_socket[1], fd, MSG_DONTWAIT);
|
||
if (r < 0)
|
||
return log_debug_errno(r, "Failed to queue file descriptor on ephemeral storage socket: %m");
|
||
|
||
if (*root_image)
|
||
free_and_replace(*root_image, new_root);
|
||
else {
|
||
assert(*root_directory);
|
||
free_and_replace(*root_directory, new_root);
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
static int verity_settings_prepare(
|
||
VeritySettings *verity,
|
||
const char *root_image,
|
||
const void *root_hash,
|
||
size_t root_hash_size,
|
||
const char *root_hash_path,
|
||
const void *root_hash_sig,
|
||
size_t root_hash_sig_size,
|
||
const char *root_hash_sig_path,
|
||
const char *verity_data_path) {
|
||
|
||
int r;
|
||
|
||
assert(verity);
|
||
|
||
if (root_hash) {
|
||
void *d;
|
||
|
||
d = memdup(root_hash, root_hash_size);
|
||
if (!d)
|
||
return -ENOMEM;
|
||
|
||
free_and_replace(verity->root_hash, d);
|
||
verity->root_hash_size = root_hash_size;
|
||
verity->designator = PARTITION_ROOT;
|
||
}
|
||
|
||
if (root_hash_sig) {
|
||
void *d;
|
||
|
||
d = memdup(root_hash_sig, root_hash_sig_size);
|
||
if (!d)
|
||
return -ENOMEM;
|
||
|
||
free_and_replace(verity->root_hash_sig, d);
|
||
verity->root_hash_sig_size = root_hash_sig_size;
|
||
verity->designator = PARTITION_ROOT;
|
||
}
|
||
|
||
if (verity_data_path) {
|
||
r = free_and_strdup(&verity->data_path, verity_data_path);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
r = verity_settings_load(
|
||
verity,
|
||
root_image,
|
||
root_hash_path,
|
||
root_hash_sig_path);
|
||
if (r < 0)
|
||
return log_debug_errno(r, "Failed to load root hash: %m");
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int pick_versions(
|
||
const ExecContext *context,
|
||
const ExecParameters *params,
|
||
char **ret_root_image,
|
||
char **ret_root_directory,
|
||
char **reterr_path) {
|
||
|
||
int r;
|
||
|
||
assert(context);
|
||
assert(params);
|
||
assert(ret_root_image);
|
||
assert(ret_root_directory);
|
||
|
||
if (context->root_image) {
|
||
_cleanup_(pick_result_done) PickResult result = PICK_RESULT_NULL;
|
||
|
||
r = path_pick(/* toplevel_path= */ NULL,
|
||
/* toplevel_fd= */ AT_FDCWD,
|
||
context->root_image,
|
||
&pick_filter_image_raw,
|
||
PICK_ARCHITECTURE|PICK_TRIES|PICK_RESOLVE,
|
||
&result);
|
||
if (r < 0) {
|
||
*reterr_path = strdup(context->root_image);
|
||
return r;
|
||
}
|
||
|
||
if (!result.path) {
|
||
*reterr_path = strdup(context->root_image);
|
||
return log_exec_debug_errno(context, params, SYNTHETIC_ERRNO(ENOENT), "No matching entry in .v/ directory %s found.", context->root_image);
|
||
}
|
||
|
||
*ret_root_image = TAKE_PTR(result.path);
|
||
*ret_root_directory = NULL;
|
||
return r;
|
||
}
|
||
|
||
if (context->root_directory) {
|
||
_cleanup_(pick_result_done) PickResult result = PICK_RESULT_NULL;
|
||
|
||
r = path_pick(/* toplevel_path= */ NULL,
|
||
/* toplevel_fd= */ AT_FDCWD,
|
||
context->root_directory,
|
||
&pick_filter_image_dir,
|
||
PICK_ARCHITECTURE|PICK_TRIES|PICK_RESOLVE,
|
||
&result);
|
||
if (r < 0) {
|
||
*reterr_path = strdup(context->root_directory);
|
||
return r;
|
||
}
|
||
|
||
if (!result.path) {
|
||
*reterr_path = strdup(context->root_directory);
|
||
return log_exec_debug_errno(context, params, SYNTHETIC_ERRNO(ENOENT), "No matching entry in .v/ directory %s found.", context->root_directory);
|
||
}
|
||
|
||
*ret_root_image = NULL;
|
||
*ret_root_directory = TAKE_PTR(result.path);
|
||
return r;
|
||
}
|
||
|
||
*ret_root_image = *ret_root_directory = NULL;
|
||
return 0;
|
||
}
|
||
|
||
static int apply_mount_namespace(
|
||
ExecCommandFlags command_flags,
|
||
const ExecContext *context,
|
||
const ExecParameters *params,
|
||
ExecRuntime *runtime,
|
||
const char *memory_pressure_path,
|
||
bool needs_sandboxing,
|
||
char **reterr_path,
|
||
uid_t exec_directory_uid,
|
||
gid_t exec_directory_gid) {
|
||
|
||
_cleanup_(verity_settings_done) VeritySettings verity = VERITY_SETTINGS_DEFAULT;
|
||
_cleanup_strv_free_ char **empty_directories = NULL, **symlinks = NULL,
|
||
**read_write_paths_cleanup = NULL;
|
||
_cleanup_free_ char *creds_path = NULL, *incoming_dir = NULL, *propagate_dir = NULL,
|
||
*private_namespace_dir = NULL, *host_os_release_stage = NULL, *root_image = NULL, *root_dir = NULL;
|
||
const char *tmp_dir = NULL, *var_tmp_dir = NULL;
|
||
char **read_write_paths;
|
||
bool setup_os_release_symlink;
|
||
BindMount *bind_mounts = NULL;
|
||
size_t n_bind_mounts = 0;
|
||
int r;
|
||
|
||
assert(context);
|
||
|
||
CLEANUP_ARRAY(bind_mounts, n_bind_mounts, bind_mount_free_many);
|
||
|
||
if (params->flags & EXEC_APPLY_CHROOT) {
|
||
r = pick_versions(
|
||
context,
|
||
params,
|
||
&root_image,
|
||
&root_dir,
|
||
reterr_path);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
r = setup_ephemeral(
|
||
context,
|
||
runtime,
|
||
&root_image,
|
||
&root_dir,
|
||
reterr_path);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
r = compile_bind_mounts(context, params, exec_directory_uid, exec_directory_gid, &bind_mounts, &n_bind_mounts, &empty_directories);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
/* We need to make the pressure path writable even if /sys/fs/cgroups is made read-only, as the
|
||
* service will need to write to it in order to start the notifications. */
|
||
if (exec_is_cgroup_mount_read_only(context, params) && memory_pressure_path && !streq(memory_pressure_path, "/dev/null")) {
|
||
read_write_paths_cleanup = strv_copy(context->read_write_paths);
|
||
if (!read_write_paths_cleanup)
|
||
return -ENOMEM;
|
||
|
||
r = strv_extend(&read_write_paths_cleanup, memory_pressure_path);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
read_write_paths = read_write_paths_cleanup;
|
||
} else
|
||
read_write_paths = context->read_write_paths;
|
||
|
||
if (needs_sandboxing) {
|
||
/* The runtime struct only contains the parent of the private /tmp, which is non-accessible
|
||
* to world users. Inside of it there's a /tmp that is sticky, and that's the one we want to
|
||
* use here. This does not apply when we are using /run/systemd/empty as fallback. */
|
||
|
||
if (context->private_tmp == PRIVATE_TMP_CONNECTED && runtime && runtime->shared) {
|
||
if (streq_ptr(runtime->shared->tmp_dir, RUN_SYSTEMD_EMPTY))
|
||
tmp_dir = runtime->shared->tmp_dir;
|
||
else if (runtime->shared->tmp_dir)
|
||
tmp_dir = strjoina(runtime->shared->tmp_dir, "/tmp");
|
||
|
||
if (streq_ptr(runtime->shared->var_tmp_dir, RUN_SYSTEMD_EMPTY))
|
||
var_tmp_dir = runtime->shared->var_tmp_dir;
|
||
else if (runtime->shared->var_tmp_dir)
|
||
var_tmp_dir = strjoina(runtime->shared->var_tmp_dir, "/tmp");
|
||
}
|
||
}
|
||
|
||
/* Symlinks (exec dirs, os-release) are set up after other mounts, before they are made read-only. */
|
||
setup_os_release_symlink = needs_sandboxing && exec_context_get_effective_mount_apivfs(context) && (root_dir || root_image);
|
||
r = compile_symlinks(context, params, setup_os_release_symlink, &symlinks);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
if (context->mount_propagation_flag == MS_SHARED)
|
||
log_exec_debug(context,
|
||
params,
|
||
"shared mount propagation hidden by other fs namespacing unit settings: ignoring");
|
||
|
||
r = exec_context_get_credential_directory(context, params, params->unit_id, &creds_path);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
if (params->runtime_scope == RUNTIME_SCOPE_SYSTEM) {
|
||
propagate_dir = path_join("/run/systemd/propagate/", params->unit_id);
|
||
if (!propagate_dir)
|
||
return -ENOMEM;
|
||
|
||
incoming_dir = strdup("/run/systemd/incoming");
|
||
if (!incoming_dir)
|
||
return -ENOMEM;
|
||
|
||
private_namespace_dir = strdup("/run/systemd");
|
||
if (!private_namespace_dir)
|
||
return -ENOMEM;
|
||
|
||
/* If running under a different root filesystem, propagate the host's os-release. We make a
|
||
* copy rather than just bind mounting it, so that it can be updated on soft-reboot. */
|
||
if (setup_os_release_symlink) {
|
||
host_os_release_stage = strdup("/run/systemd/propagate/.os-release-stage");
|
||
if (!host_os_release_stage)
|
||
return -ENOMEM;
|
||
}
|
||
} else {
|
||
assert(params->runtime_scope == RUNTIME_SCOPE_USER);
|
||
|
||
if (asprintf(&private_namespace_dir, "/run/user/" UID_FMT "/systemd", geteuid()) < 0)
|
||
return -ENOMEM;
|
||
|
||
if (setup_os_release_symlink) {
|
||
if (asprintf(&host_os_release_stage,
|
||
"/run/user/" UID_FMT "/systemd/propagate/.os-release-stage",
|
||
geteuid()) < 0)
|
||
return -ENOMEM;
|
||
}
|
||
}
|
||
|
||
if (root_image) {
|
||
r = verity_settings_prepare(
|
||
&verity,
|
||
root_image,
|
||
context->root_hash, context->root_hash_size, context->root_hash_path,
|
||
context->root_hash_sig, context->root_hash_sig_size, context->root_hash_sig_path,
|
||
context->root_verity);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
NamespaceParameters parameters = {
|
||
.runtime_scope = params->runtime_scope,
|
||
|
||
.root_directory = root_dir,
|
||
.root_image = root_image,
|
||
.root_image_options = context->root_image_options,
|
||
.root_image_policy = context->root_image_policy ?: &image_policy_service,
|
||
|
||
.read_write_paths = read_write_paths,
|
||
.read_only_paths = needs_sandboxing ? context->read_only_paths : NULL,
|
||
.inaccessible_paths = needs_sandboxing ? context->inaccessible_paths : NULL,
|
||
|
||
.exec_paths = needs_sandboxing ? context->exec_paths : NULL,
|
||
.no_exec_paths = needs_sandboxing ? context->no_exec_paths : NULL,
|
||
|
||
.empty_directories = empty_directories,
|
||
.symlinks = symlinks,
|
||
|
||
.bind_mounts = bind_mounts,
|
||
.n_bind_mounts = n_bind_mounts,
|
||
|
||
.temporary_filesystems = context->temporary_filesystems,
|
||
.n_temporary_filesystems = context->n_temporary_filesystems,
|
||
|
||
.mount_images = context->mount_images,
|
||
.n_mount_images = context->n_mount_images,
|
||
.mount_image_policy = context->mount_image_policy ?: &image_policy_service,
|
||
|
||
.tmp_dir = tmp_dir,
|
||
.var_tmp_dir = var_tmp_dir,
|
||
|
||
.creds_path = creds_path,
|
||
.log_namespace = context->log_namespace,
|
||
.mount_propagation_flag = context->mount_propagation_flag,
|
||
|
||
.verity = &verity,
|
||
|
||
.extension_images = context->extension_images,
|
||
.n_extension_images = context->n_extension_images,
|
||
.extension_image_policy = context->extension_image_policy ?: &image_policy_sysext,
|
||
.extension_directories = context->extension_directories,
|
||
|
||
.propagate_dir = propagate_dir,
|
||
.incoming_dir = incoming_dir,
|
||
.private_namespace_dir = private_namespace_dir,
|
||
.host_notify_socket = params->notify_socket,
|
||
.notify_socket_path = exec_get_private_notify_socket_path(context, params, needs_sandboxing),
|
||
.host_os_release_stage = host_os_release_stage,
|
||
|
||
/* If DynamicUser=no and RootDirectory= is set then lets pass a relaxed sandbox info,
|
||
* otherwise enforce it, don't ignore protected paths and fail if we are enable to apply the
|
||
* sandbox inside the mount namespace. */
|
||
.ignore_protect_paths = !needs_sandboxing && !context->dynamic_user && root_dir,
|
||
|
||
.protect_control_groups = needs_sandboxing ? exec_get_protect_control_groups(context, params) : PROTECT_CONTROL_GROUPS_NO,
|
||
.protect_kernel_tunables = needs_sandboxing && context->protect_kernel_tunables,
|
||
.protect_kernel_modules = needs_sandboxing && context->protect_kernel_modules,
|
||
.protect_kernel_logs = needs_sandboxing && context->protect_kernel_logs,
|
||
|
||
.private_dev = needs_sandboxing && context->private_devices,
|
||
.private_network = needs_sandboxing && exec_needs_network_namespace(context),
|
||
.private_ipc = needs_sandboxing && exec_needs_ipc_namespace(context),
|
||
.private_pids = needs_sandboxing && exec_needs_pid_namespace(context) ? context->private_pids : PRIVATE_PIDS_NO,
|
||
.private_tmp = needs_sandboxing ? context->private_tmp : PRIVATE_TMP_NO,
|
||
|
||
.mount_apivfs = needs_sandboxing && exec_context_get_effective_mount_apivfs(context),
|
||
.bind_log_sockets = needs_sandboxing && exec_context_get_effective_bind_log_sockets(context),
|
||
|
||
/* If NNP is on, we can turn on MS_NOSUID, since it won't have any effect anymore. */
|
||
.mount_nosuid = needs_sandboxing && context->no_new_privileges && !mac_selinux_use(),
|
||
|
||
.protect_home = needs_sandboxing ? context->protect_home : PROTECT_HOME_NO,
|
||
.protect_hostname = needs_sandboxing ? context->protect_hostname : PROTECT_HOSTNAME_NO,
|
||
.protect_system = needs_sandboxing ? context->protect_system : PROTECT_SYSTEM_NO,
|
||
.protect_proc = needs_sandboxing ? context->protect_proc : PROTECT_PROC_DEFAULT,
|
||
.proc_subset = needs_sandboxing ? context->proc_subset : PROC_SUBSET_ALL,
|
||
};
|
||
|
||
r = setup_namespace(¶meters, reterr_path);
|
||
/* If we couldn't set up the namespace this is probably due to a missing capability. setup_namespace() reports
|
||
* that with a special, recognizable error ENOANO. In this case, silently proceed, but only if exclusively
|
||
* sandboxing options were used, i.e. nothing such as RootDirectory= or BindMount= that would result in a
|
||
* completely different execution environment. */
|
||
if (r == -ENOANO) {
|
||
if (insist_on_sandboxing(
|
||
context,
|
||
root_dir, root_image,
|
||
bind_mounts,
|
||
n_bind_mounts))
|
||
return log_exec_debug_errno(context,
|
||
params,
|
||
SYNTHETIC_ERRNO(EOPNOTSUPP),
|
||
"Failed to set up namespace, and refusing to continue since "
|
||
"the selected namespacing options alter mount environment non-trivially.\n"
|
||
"Bind mounts: %zu, temporary filesystems: %zu, root directory: %s, root image: %s, dynamic user: %s",
|
||
n_bind_mounts,
|
||
context->n_temporary_filesystems,
|
||
yes_no(root_dir),
|
||
yes_no(root_image),
|
||
yes_no(context->dynamic_user));
|
||
|
||
log_exec_debug(context, params, "Failed to set up namespace, assuming containerized execution and ignoring.");
|
||
return 0;
|
||
}
|
||
|
||
return r;
|
||
}
|
||
|
||
static int apply_working_directory(
|
||
const ExecContext *context,
|
||
const ExecParameters *params,
|
||
ExecRuntime *runtime,
|
||
const char *home) {
|
||
|
||
const char *wd;
|
||
int r;
|
||
|
||
assert(context);
|
||
|
||
if (context->working_directory_home) {
|
||
if (!home)
|
||
return -ENXIO;
|
||
|
||
wd = home;
|
||
} else
|
||
wd = empty_to_root(context->working_directory);
|
||
|
||
if (params->flags & EXEC_APPLY_CHROOT)
|
||
r = RET_NERRNO(chdir(wd));
|
||
else {
|
||
_cleanup_close_ int dfd = -EBADF;
|
||
|
||
r = chase(wd,
|
||
(runtime ? runtime->ephemeral_copy : NULL) ?: context->root_directory,
|
||
CHASE_PREFIX_ROOT|CHASE_AT_RESOLVE_IN_ROOT,
|
||
/* ret_path= */ NULL,
|
||
&dfd);
|
||
if (r >= 0)
|
||
r = RET_NERRNO(fchdir(dfd));
|
||
}
|
||
return context->working_directory_missing_ok ? 0 : r;
|
||
}
|
||
|
||
static int apply_root_directory(
|
||
const ExecContext *context,
|
||
const ExecParameters *params,
|
||
ExecRuntime *runtime,
|
||
const bool needs_mount_ns,
|
||
int *exit_status) {
|
||
|
||
assert(context);
|
||
assert(exit_status);
|
||
|
||
if (params->flags & EXEC_APPLY_CHROOT)
|
||
if (!needs_mount_ns && context->root_directory)
|
||
if (chroot((runtime ? runtime->ephemeral_copy : NULL) ?: context->root_directory) < 0) {
|
||
*exit_status = EXIT_CHROOT;
|
||
return -errno;
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int setup_keyring(
|
||
const ExecContext *context,
|
||
const ExecParameters *p,
|
||
uid_t uid, gid_t gid) {
|
||
|
||
key_serial_t keyring;
|
||
int r = 0;
|
||
uid_t saved_uid;
|
||
gid_t saved_gid;
|
||
|
||
assert(context);
|
||
assert(p);
|
||
|
||
/* Let's set up a new per-service "session" kernel keyring for each system service. This has the benefit that
|
||
* each service runs with its own keyring shared among all processes of the service, but with no hook-up beyond
|
||
* that scope, and in particular no link to the per-UID keyring. If we don't do this the keyring will be
|
||
* automatically created on-demand and then linked to the per-UID keyring, by the kernel. The kernel's built-in
|
||
* on-demand behaviour is very appropriate for login users, but probably not so much for system services, where
|
||
* UIDs are not necessarily specific to a service but reused (at least in the case of UID 0). */
|
||
|
||
if (context->keyring_mode == EXEC_KEYRING_INHERIT)
|
||
return 0;
|
||
|
||
/* Acquiring a reference to the user keyring is nasty. We briefly change identity in order to get things set up
|
||
* properly by the kernel. If we don't do that then we can't create it atomically, and that sucks for parallel
|
||
* execution. This mimics what pam_keyinit does, too. Setting up session keyring, to be owned by the right user
|
||
* & group is just as nasty as acquiring a reference to the user keyring. */
|
||
|
||
saved_uid = getuid();
|
||
saved_gid = getgid();
|
||
|
||
if (gid_is_valid(gid) && gid != saved_gid) {
|
||
if (setregid(gid, -1) < 0)
|
||
return log_exec_error_errno(context,
|
||
p,
|
||
errno,
|
||
"Failed to change GID for user keyring: %m");
|
||
}
|
||
|
||
if (uid_is_valid(uid) && uid != saved_uid) {
|
||
if (setreuid(uid, -1) < 0) {
|
||
r = log_exec_error_errno(context,
|
||
p,
|
||
errno,
|
||
"Failed to change UID for user keyring: %m");
|
||
goto out;
|
||
}
|
||
}
|
||
|
||
keyring = keyctl(KEYCTL_JOIN_SESSION_KEYRING, 0, 0, 0, 0);
|
||
if (keyring == -1) {
|
||
if (errno == ENOSYS)
|
||
log_exec_debug_errno(context,
|
||
p,
|
||
errno,
|
||
"Kernel keyring not supported, ignoring.");
|
||
else if (ERRNO_IS_PRIVILEGE(errno))
|
||
log_exec_debug_errno(context,
|
||
p,
|
||
errno,
|
||
"Kernel keyring access prohibited, ignoring.");
|
||
else if (errno == EDQUOT)
|
||
log_exec_debug_errno(context,
|
||
p,
|
||
errno,
|
||
"Out of kernel keyrings to allocate, ignoring.");
|
||
else
|
||
r = log_exec_error_errno(context,
|
||
p,
|
||
errno,
|
||
"Setting up kernel keyring failed: %m");
|
||
|
||
goto out;
|
||
}
|
||
|
||
/* When requested link the user keyring into the session keyring. */
|
||
if (context->keyring_mode == EXEC_KEYRING_SHARED) {
|
||
|
||
if (keyctl(KEYCTL_LINK,
|
||
KEY_SPEC_USER_KEYRING,
|
||
KEY_SPEC_SESSION_KEYRING, 0, 0) < 0) {
|
||
r = log_exec_error_errno(context,
|
||
p,
|
||
errno,
|
||
"Failed to link user keyring into session keyring: %m");
|
||
goto out;
|
||
}
|
||
}
|
||
|
||
/* Restore uid/gid back */
|
||
if (uid_is_valid(uid) && uid != saved_uid) {
|
||
if (setreuid(saved_uid, -1) < 0) {
|
||
r = log_exec_error_errno(context,
|
||
p,
|
||
errno,
|
||
"Failed to change UID back for user keyring: %m");
|
||
goto out;
|
||
}
|
||
}
|
||
|
||
if (gid_is_valid(gid) && gid != saved_gid) {
|
||
if (setregid(saved_gid, -1) < 0)
|
||
return log_exec_error_errno(context,
|
||
p,
|
||
errno,
|
||
"Failed to change GID back for user keyring: %m");
|
||
}
|
||
|
||
/* Populate they keyring with the invocation ID by default, as original saved_uid. */
|
||
if (!sd_id128_is_null(p->invocation_id)) {
|
||
key_serial_t key;
|
||
|
||
key = add_key("user",
|
||
"invocation_id",
|
||
&p->invocation_id,
|
||
sizeof(p->invocation_id),
|
||
KEY_SPEC_SESSION_KEYRING);
|
||
if (key == -1)
|
||
log_exec_debug_errno(context,
|
||
p,
|
||
errno,
|
||
"Failed to add invocation ID to keyring, ignoring: %m");
|
||
else {
|
||
if (keyctl(KEYCTL_SETPERM, key,
|
||
KEY_POS_VIEW|KEY_POS_READ|KEY_POS_SEARCH|
|
||
KEY_USR_VIEW|KEY_USR_READ|KEY_USR_SEARCH, 0, 0) < 0)
|
||
r = log_exec_error_errno(context,
|
||
p,
|
||
errno,
|
||
"Failed to restrict invocation ID permission: %m");
|
||
}
|
||
}
|
||
|
||
out:
|
||
/* Revert back uid & gid for the last time, and exit */
|
||
/* no extra logging, as only the first already reported error matters */
|
||
if (getuid() != saved_uid)
|
||
(void) setreuid(saved_uid, -1);
|
||
|
||
if (getgid() != saved_gid)
|
||
(void) setregid(saved_gid, -1);
|
||
|
||
return r;
|
||
}
|
||
|
||
static void append_socket_pair(int *array, size_t *n, const int pair[static 2]) {
|
||
assert(array);
|
||
assert(n);
|
||
assert(pair);
|
||
|
||
if (pair[0] >= 0)
|
||
array[(*n)++] = pair[0];
|
||
if (pair[1] >= 0)
|
||
array[(*n)++] = pair[1];
|
||
}
|
||
|
||
static int close_remaining_fds(
|
||
const ExecParameters *params,
|
||
const ExecRuntime *runtime,
|
||
int socket_fd,
|
||
const int *fds, size_t n_fds) {
|
||
|
||
size_t n_dont_close = 0;
|
||
int dont_close[n_fds + 17];
|
||
|
||
assert(params);
|
||
|
||
if (params->stdin_fd >= 0)
|
||
dont_close[n_dont_close++] = params->stdin_fd;
|
||
if (params->stdout_fd >= 0)
|
||
dont_close[n_dont_close++] = params->stdout_fd;
|
||
if (params->stderr_fd >= 0)
|
||
dont_close[n_dont_close++] = params->stderr_fd;
|
||
|
||
if (socket_fd >= 0)
|
||
dont_close[n_dont_close++] = socket_fd;
|
||
if (n_fds > 0) {
|
||
memcpy(dont_close + n_dont_close, fds, sizeof(int) * n_fds);
|
||
n_dont_close += n_fds;
|
||
}
|
||
|
||
if (runtime)
|
||
append_socket_pair(dont_close, &n_dont_close, runtime->ephemeral_storage_socket);
|
||
|
||
if (runtime && runtime->shared) {
|
||
append_socket_pair(dont_close, &n_dont_close, runtime->shared->netns_storage_socket);
|
||
append_socket_pair(dont_close, &n_dont_close, runtime->shared->ipcns_storage_socket);
|
||
}
|
||
|
||
if (runtime && runtime->dynamic_creds) {
|
||
if (runtime->dynamic_creds->user)
|
||
append_socket_pair(dont_close, &n_dont_close, runtime->dynamic_creds->user->storage_socket);
|
||
if (runtime->dynamic_creds->group)
|
||
append_socket_pair(dont_close, &n_dont_close, runtime->dynamic_creds->group->storage_socket);
|
||
}
|
||
|
||
if (params->user_lookup_fd >= 0)
|
||
dont_close[n_dont_close++] = params->user_lookup_fd;
|
||
|
||
if (params->handoff_timestamp_fd >= 0)
|
||
dont_close[n_dont_close++] = params->handoff_timestamp_fd;
|
||
|
||
if (params->pidref_transport_fd >= 0)
|
||
dont_close[n_dont_close++] = params->pidref_transport_fd;
|
||
|
||
assert(n_dont_close <= ELEMENTSOF(dont_close));
|
||
|
||
return close_all_fds(dont_close, n_dont_close);
|
||
}
|
||
|
||
static int send_user_lookup(
|
||
const char *unit_id,
|
||
int user_lookup_fd,
|
||
uid_t uid,
|
||
gid_t gid) {
|
||
|
||
assert(unit_id);
|
||
|
||
/* Send the resolved UID/GID to PID 1 after we learnt it. We send a single datagram, containing the UID/GID
|
||
* data as well as the unit name. Note that we suppress sending this if no user/group to resolve was
|
||
* specified. */
|
||
|
||
if (user_lookup_fd < 0)
|
||
return 0;
|
||
|
||
if (!uid_is_valid(uid) && !gid_is_valid(gid))
|
||
return 0;
|
||
|
||
if (writev(user_lookup_fd,
|
||
(struct iovec[]) {
|
||
IOVEC_MAKE(&uid, sizeof(uid)),
|
||
IOVEC_MAKE(&gid, sizeof(gid)),
|
||
IOVEC_MAKE_STRING(unit_id) }, 3) < 0)
|
||
return -errno;
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int acquire_home(const ExecContext *c, const char **home, char **ret_buf) {
|
||
int r;
|
||
|
||
assert(c);
|
||
assert(home);
|
||
assert(ret_buf);
|
||
|
||
/* If WorkingDirectory=~ is set, try to acquire a usable home directory. */
|
||
|
||
if (*home) /* Already acquired from get_fixed_user()? */
|
||
return 0;
|
||
|
||
if (!c->working_directory_home)
|
||
return 0;
|
||
|
||
if (c->dynamic_user || (c->user && is_this_me(c->user) <= 0))
|
||
return -EADDRNOTAVAIL;
|
||
|
||
r = get_home_dir(ret_buf);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
*home = *ret_buf;
|
||
return 1;
|
||
}
|
||
|
||
static int compile_suggested_paths(const ExecContext *c, const ExecParameters *p, char ***ret) {
|
||
_cleanup_strv_free_ char ** list = NULL;
|
||
int r;
|
||
|
||
assert(c);
|
||
assert(p);
|
||
assert(ret);
|
||
|
||
assert(c->dynamic_user);
|
||
|
||
/* Compile a list of paths that it might make sense to read the owning UID from to use as initial candidate for
|
||
* dynamic UID allocation, in order to save us from doing costly recursive chown()s of the special
|
||
* directories. */
|
||
|
||
for (ExecDirectoryType t = 0; t < _EXEC_DIRECTORY_TYPE_MAX; t++) {
|
||
|
||
if (!EXEC_DIRECTORY_TYPE_SHALL_CHOWN(t))
|
||
continue;
|
||
|
||
if (!p->prefix[t])
|
||
continue;
|
||
|
||
for (size_t i = 0; i < c->directories[t].n_items; i++) {
|
||
char *e;
|
||
|
||
if (exec_directory_is_private(c, t))
|
||
e = path_join(p->prefix[t], "private", c->directories[t].items[i].path);
|
||
else
|
||
e = path_join(p->prefix[t], c->directories[t].items[i].path);
|
||
if (!e)
|
||
return -ENOMEM;
|
||
|
||
r = strv_consume(&list, e);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
}
|
||
|
||
*ret = TAKE_PTR(list);
|
||
|
||
return 0;
|
||
}
|
||
|
||
static int exec_context_cpu_affinity_from_numa(const ExecContext *c, CPUSet *ret) {
|
||
_cleanup_(cpu_set_reset) CPUSet s = {};
|
||
int r;
|
||
|
||
assert(c);
|
||
assert(ret);
|
||
|
||
if (!c->numa_policy.nodes.set) {
|
||
log_debug("Can't derive CPU affinity mask from NUMA mask because NUMA mask is not set, ignoring");
|
||
return 0;
|
||
}
|
||
|
||
r = numa_to_cpu_set(&c->numa_policy, &s);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
cpu_set_reset(ret);
|
||
|
||
return cpu_set_add_all(ret, &s);
|
||
}
|
||
|
||
static int add_shifted_fd(int *fds, size_t fds_size, size_t *n_fds, int *fd) {
|
||
int r;
|
||
|
||
assert(fds);
|
||
assert(n_fds);
|
||
assert(*n_fds < fds_size);
|
||
assert(fd);
|
||
|
||
if (*fd < 0)
|
||
return 0;
|
||
|
||
if (*fd < 3 + (int) *n_fds) {
|
||
/* Let's move the fd up, so that it's outside of the fd range we will use to store
|
||
* the fds we pass to the process (or which are closed only during execve). */
|
||
|
||
r = fcntl(*fd, F_DUPFD_CLOEXEC, 3 + (int) *n_fds);
|
||
if (r < 0)
|
||
return -errno;
|
||
|
||
close_and_replace(*fd, r);
|
||
}
|
||
|
||
fds[(*n_fds)++] = *fd;
|
||
return 1;
|
||
}
|
||
|
||
static int connect_unix_harder(const ExecContext *c, const ExecParameters *p, const OpenFile *of, int ofd) {
|
||
static const int socket_types[] = { SOCK_DGRAM, SOCK_STREAM, SOCK_SEQPACKET };
|
||
|
||
union sockaddr_union addr = {
|
||
.un.sun_family = AF_UNIX,
|
||
};
|
||
socklen_t sa_len;
|
||
int r;
|
||
|
||
assert(c);
|
||
assert(p);
|
||
assert(of);
|
||
assert(ofd >= 0);
|
||
|
||
r = sockaddr_un_set_path(&addr.un, FORMAT_PROC_FD_PATH(ofd));
|
||
if (r < 0)
|
||
return log_exec_debug_errno(c, p, r, "Failed to set sockaddr for '%s': %m", of->path);
|
||
sa_len = r;
|
||
|
||
FOREACH_ELEMENT(i, socket_types) {
|
||
_cleanup_close_ int fd = -EBADF;
|
||
|
||
fd = socket(AF_UNIX, *i|SOCK_CLOEXEC, 0);
|
||
if (fd < 0)
|
||
return log_exec_debug_errno(c, p,
|
||
errno, "Failed to create socket for '%s': %m",
|
||
of->path);
|
||
|
||
r = RET_NERRNO(connect(fd, &addr.sa, sa_len));
|
||
if (r >= 0)
|
||
return TAKE_FD(fd);
|
||
if (r != -EPROTOTYPE)
|
||
return log_exec_debug_errno(c, p,
|
||
r, "Failed to connect to socket for '%s': %m",
|
||
of->path);
|
||
}
|
||
|
||
return log_exec_debug_errno(c, p,
|
||
SYNTHETIC_ERRNO(EPROTOTYPE), "No suitable socket type to connect to socket '%s'.",
|
||
of->path);
|
||
}
|
||
|
||
static int get_open_file_fd(const ExecContext *c, const ExecParameters *p, const OpenFile *of) {
|
||
_cleanup_close_ int fd = -EBADF, ofd = -EBADF;
|
||
struct stat st;
|
||
|
||
assert(c);
|
||
assert(p);
|
||
assert(of);
|
||
|
||
ofd = open(of->path, O_PATH | O_CLOEXEC);
|
||
if (ofd < 0)
|
||
return log_exec_debug_errno(c, p, errno, "Failed to open '%s' as O_PATH: %m", of->path);
|
||
|
||
if (fstat(ofd, &st) < 0)
|
||
return log_exec_debug_errno(c, p, errno, "Failed to stat '%s': %m", of->path);
|
||
|
||
if (S_ISSOCK(st.st_mode)) {
|
||
fd = connect_unix_harder(c, p, of, ofd);
|
||
if (fd < 0)
|
||
return fd;
|
||
|
||
if (FLAGS_SET(of->flags, OPENFILE_READ_ONLY) && shutdown(fd, SHUT_WR) < 0)
|
||
return log_exec_debug_errno(c, p,
|
||
errno, "Failed to shutdown send for socket '%s': %m",
|
||
of->path);
|
||
|
||
log_exec_debug(c, p, "Opened socket '%s' as fd %d.", of->path, fd);
|
||
} else {
|
||
int flags = FLAGS_SET(of->flags, OPENFILE_READ_ONLY) ? O_RDONLY : O_RDWR;
|
||
if (FLAGS_SET(of->flags, OPENFILE_APPEND))
|
||
flags |= O_APPEND;
|
||
else if (FLAGS_SET(of->flags, OPENFILE_TRUNCATE))
|
||
flags |= O_TRUNC;
|
||
|
||
fd = fd_reopen(ofd, flags|O_NOCTTY|O_CLOEXEC);
|
||
if (fd < 0)
|
||
return log_exec_debug_errno(c, p, fd, "Failed to reopen file '%s': %m", of->path);
|
||
|
||
log_exec_debug(c, p, "Opened file '%s' as fd %d.", of->path, fd);
|
||
}
|
||
|
||
return TAKE_FD(fd);
|
||
}
|
||
|
||
static int collect_open_file_fds(const ExecContext *c, ExecParameters *p, size_t *n_fds) {
|
||
assert(c);
|
||
assert(p);
|
||
assert(n_fds);
|
||
|
||
LIST_FOREACH(open_files, of, p->open_files) {
|
||
_cleanup_close_ int fd = -EBADF;
|
||
|
||
fd = get_open_file_fd(c, p, of);
|
||
if (fd < 0) {
|
||
if (FLAGS_SET(of->flags, OPENFILE_GRACEFUL)) {
|
||
log_exec_full_errno(c, p,
|
||
fd == -ENOENT || ERRNO_IS_NEG_PRIVILEGE(fd) ? LOG_DEBUG : LOG_WARNING,
|
||
fd,
|
||
"Failed to get OpenFile= file descriptor for '%s', ignoring: %m",
|
||
of->path);
|
||
continue;
|
||
}
|
||
|
||
return log_exec_error_errno(c, p, fd,
|
||
"Failed to get OpenFile= file descriptor for '%s': %m",
|
||
of->path);
|
||
}
|
||
|
||
if (!GREEDY_REALLOC(p->fds, *n_fds + 1))
|
||
return log_oom();
|
||
|
||
if (strv_extend(&p->fd_names, of->fdname) < 0)
|
||
return log_oom();
|
||
|
||
p->fds[(*n_fds)++] = TAKE_FD(fd);
|
||
}
|
||
|
||
return 0;
|
||
}
|
||
|
||
static void log_command_line(
|
||
const ExecContext *context,
|
||
const ExecParameters *params,
|
||
const char *msg,
|
||
const char *executable,
|
||
char **argv) {
|
||
|
||
assert(context);
|
||
assert(params);
|
||
assert(msg);
|
||
assert(executable);
|
||
|
||
if (!DEBUG_LOGGING)
|
||
return;
|
||
|
||
_cleanup_free_ char *cmdline = quote_command_line(argv, SHELL_ESCAPE_EMPTY);
|
||
|
||
log_exec_struct(context, params, LOG_DEBUG,
|
||
"EXECUTABLE=%s", executable,
|
||
LOG_EXEC_MESSAGE(params, "%s: %s", msg, strnull(cmdline)),
|
||
LOG_EXEC_INVOCATION_ID(params));
|
||
}
|
||
|
||
static bool exec_context_need_unprivileged_private_users(
|
||
const ExecContext *context,
|
||
const ExecParameters *params) {
|
||
|
||
assert(context);
|
||
assert(params);
|
||
|
||
/* These options require PrivateUsers= when used in user units, as we need to be in a user namespace
|
||
* to have permission to enable them when not running as root. If we have effective CAP_SYS_ADMIN
|
||
* (system manager) then we have privileges and don't need this. */
|
||
if (params->runtime_scope != RUNTIME_SCOPE_USER)
|
||
return false;
|
||
|
||
return context->private_users != PRIVATE_USERS_NO ||
|
||
context->private_tmp != PRIVATE_TMP_NO ||
|
||
context->private_devices ||
|
||
context->private_network ||
|
||
context->network_namespace_path ||
|
||
context->private_ipc ||
|
||
context->ipc_namespace_path ||
|
||
context->private_mounts > 0 ||
|
||
context->mount_apivfs > 0 ||
|
||
context->bind_log_sockets > 0 ||
|
||
context->n_bind_mounts > 0 ||
|
||
context->n_temporary_filesystems > 0 ||
|
||
context->root_directory ||
|
||
!strv_isempty(context->extension_directories) ||
|
||
context->protect_system != PROTECT_SYSTEM_NO ||
|
||
context->protect_home != PROTECT_HOME_NO ||
|
||
exec_needs_pid_namespace(context) ||
|
||
context->protect_kernel_tunables ||
|
||
context->protect_kernel_modules ||
|
||
context->protect_kernel_logs ||
|
||
exec_needs_cgroup_mount(context, params) ||
|
||
context->protect_clock ||
|
||
context->protect_hostname != PROTECT_HOSTNAME_NO ||
|
||
!strv_isempty(context->read_write_paths) ||
|
||
!strv_isempty(context->read_only_paths) ||
|
||
!strv_isempty(context->inaccessible_paths) ||
|
||
!strv_isempty(context->exec_paths) ||
|
||
!strv_isempty(context->no_exec_paths);
|
||
}
|
||
|
||
static bool exec_context_shall_confirm_spawn(const ExecContext *context) {
|
||
assert(context);
|
||
|
||
if (confirm_spawn_disabled())
|
||
return false;
|
||
|
||
/* For some reasons units remaining in the same process group
|
||
* as PID 1 fail to acquire the console even if it's not used
|
||
* by any process. So skip the confirmation question for them. */
|
||
return !context->same_pgrp;
|
||
}
|
||
|
||
static int exec_context_named_iofds(
|
||
const ExecContext *c,
|
||
const ExecParameters *p,
|
||
int named_iofds[static 3]) {
|
||
|
||
size_t targets;
|
||
const char* stdio_fdname[3];
|
||
size_t n_fds;
|
||
|
||
assert(c);
|
||
assert(p);
|
||
assert(named_iofds);
|
||
|
||
targets = (c->std_input == EXEC_INPUT_NAMED_FD) +
|
||
(c->std_output == EXEC_OUTPUT_NAMED_FD) +
|
||
(c->std_error == EXEC_OUTPUT_NAMED_FD);
|
||
|
||
for (size_t i = 0; i < 3; i++)
|
||
stdio_fdname[i] = exec_context_fdname(c, i);
|
||
|
||
n_fds = p->n_storage_fds + p->n_socket_fds + p->n_extra_fds;
|
||
|
||
for (size_t i = 0; i < n_fds && targets > 0; i++)
|
||
if (named_iofds[STDIN_FILENO] < 0 &&
|
||
c->std_input == EXEC_INPUT_NAMED_FD &&
|
||
stdio_fdname[STDIN_FILENO] &&
|
||
streq(p->fd_names[i], stdio_fdname[STDIN_FILENO])) {
|
||
|
||
named_iofds[STDIN_FILENO] = p->fds[i];
|
||
targets--;
|
||
|
||
} else if (named_iofds[STDOUT_FILENO] < 0 &&
|
||
c->std_output == EXEC_OUTPUT_NAMED_FD &&
|
||
stdio_fdname[STDOUT_FILENO] &&
|
||
streq(p->fd_names[i], stdio_fdname[STDOUT_FILENO])) {
|
||
|
||
named_iofds[STDOUT_FILENO] = p->fds[i];
|
||
targets--;
|
||
|
||
} else if (named_iofds[STDERR_FILENO] < 0 &&
|
||
c->std_error == EXEC_OUTPUT_NAMED_FD &&
|
||
stdio_fdname[STDERR_FILENO] &&
|
||
streq(p->fd_names[i], stdio_fdname[STDERR_FILENO])) {
|
||
|
||
named_iofds[STDERR_FILENO] = p->fds[i];
|
||
targets--;
|
||
}
|
||
|
||
return targets == 0 ? 0 : -ENOENT;
|
||
}
|
||
|
||
static void exec_shared_runtime_close(ExecSharedRuntime *shared) {
|
||
if (!shared)
|
||
return;
|
||
|
||
safe_close_pair(shared->netns_storage_socket);
|
||
safe_close_pair(shared->ipcns_storage_socket);
|
||
}
|
||
|
||
static void exec_runtime_close(ExecRuntime *rt) {
|
||
if (!rt)
|
||
return;
|
||
|
||
safe_close_pair(rt->ephemeral_storage_socket);
|
||
|
||
exec_shared_runtime_close(rt->shared);
|
||
dynamic_creds_close(rt->dynamic_creds);
|
||
}
|
||
|
||
static void exec_params_close(ExecParameters *p) {
|
||
if (!p)
|
||
return;
|
||
|
||
p->stdin_fd = safe_close(p->stdin_fd);
|
||
p->stdout_fd = safe_close(p->stdout_fd);
|
||
p->stderr_fd = safe_close(p->stderr_fd);
|
||
}
|
||
|
||
static int exec_fd_mark_hot(
|
||
const ExecContext *c,
|
||
ExecParameters *p,
|
||
bool hot,
|
||
int *reterr_exit_status) {
|
||
|
||
assert(c);
|
||
assert(p);
|
||
|
||
if (p->exec_fd < 0)
|
||
return 0;
|
||
|
||
uint8_t x = hot;
|
||
|
||
if (write(p->exec_fd, &x, sizeof(x)) < 0) {
|
||
if (reterr_exit_status)
|
||
*reterr_exit_status = EXIT_EXEC;
|
||
return log_exec_error_errno(c, p, errno, "Failed to mark exec_fd as %s: %m", hot ? "hot" : "cold");
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
static int send_handoff_timestamp(
|
||
const ExecContext *c,
|
||
ExecParameters *p,
|
||
int *reterr_exit_status) {
|
||
|
||
assert(c);
|
||
assert(p);
|
||
|
||
if (p->handoff_timestamp_fd < 0)
|
||
return 0;
|
||
|
||
dual_timestamp dt;
|
||
dual_timestamp_now(&dt);
|
||
|
||
if (write(p->handoff_timestamp_fd, (const usec_t[2]) { dt.realtime, dt.monotonic }, sizeof(usec_t) * 2) < 0) {
|
||
if (reterr_exit_status)
|
||
*reterr_exit_status = EXIT_EXEC;
|
||
return log_exec_error_errno(c, p, errno, "Failed to send handoff timestamp: %m");
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
static void prepare_terminal(
|
||
const ExecContext *context,
|
||
ExecParameters *p) {
|
||
|
||
_cleanup_close_ int lock_fd = -EBADF;
|
||
|
||
/* This is the "constructive" reset, i.e. is about preparing things for our invocation rather than
|
||
* cleaning up things from older invocations. */
|
||
|
||
assert(context);
|
||
assert(p);
|
||
|
||
/* We only try to reset things if we there's the chance our stdout points to a TTY */
|
||
if (!(is_terminal_output(context->std_output) ||
|
||
(context->std_output == EXEC_OUTPUT_INHERIT && is_terminal_input(context->std_input)) ||
|
||
context->std_output == EXEC_OUTPUT_NAMED_FD ||
|
||
p->stdout_fd >= 0))
|
||
return;
|
||
|
||
if (context->tty_reset) {
|
||
/* When we are resetting the TTY, then let's create a lock first, to synchronize access. This
|
||
* in particular matters as concurrent resets and the TTY size ANSI DSR logic done by the
|
||
* exec_context_apply_tty_size() below might interfere */
|
||
lock_fd = lock_dev_console();
|
||
if (lock_fd < 0)
|
||
log_exec_debug_errno(context, p, lock_fd, "Failed to lock /dev/console, ignoring: %m");
|
||
|
||
(void) terminal_reset_defensive(STDOUT_FILENO, /* switch_to_text= */ false);
|
||
}
|
||
|
||
(void) exec_context_apply_tty_size(context, STDIN_FILENO, STDOUT_FILENO, /* tty_path= */ NULL);
|
||
}
|
||
|
||
int exec_invoke(
|
||
const ExecCommand *command,
|
||
const ExecContext *context,
|
||
ExecParameters *params,
|
||
ExecRuntime *runtime,
|
||
const CGroupContext *cgroup_context,
|
||
int *exit_status) {
|
||
|
||
_cleanup_strv_free_ char **our_env = NULL, **pass_env = NULL, **joined_exec_search_path = NULL, **accum_env = NULL, **replaced_argv = NULL;
|
||
int r, ngids = 0;
|
||
_cleanup_free_ gid_t *supplementary_gids = NULL;
|
||
const char *username = NULL, *groupname = NULL;
|
||
_cleanup_free_ char *home_buffer = NULL, *memory_pressure_path = NULL, *own_user = NULL;
|
||
const char *home = NULL, *shell = NULL;
|
||
char **final_argv = NULL;
|
||
dev_t journal_stream_dev = 0;
|
||
ino_t journal_stream_ino = 0;
|
||
bool userns_set_up = false;
|
||
bool needs_sandboxing, /* Do we need to set up full sandboxing? (i.e. all namespacing, all MAC stuff, caps, yadda yadda */
|
||
needs_setuid, /* Do we need to do the actual setresuid()/setresgid() calls? */
|
||
needs_mount_namespace; /* Do we need to set up a mount namespace for this kernel? */
|
||
bool keep_seccomp_privileges = false;
|
||
bool has_cap_sys_admin = false;
|
||
#if HAVE_SELINUX
|
||
_cleanup_free_ char *mac_selinux_context_net = NULL;
|
||
bool use_selinux = false;
|
||
#endif
|
||
#if ENABLE_SMACK
|
||
bool use_smack = false;
|
||
#endif
|
||
#if HAVE_APPARMOR
|
||
bool use_apparmor = false;
|
||
#endif
|
||
#if HAVE_SECCOMP
|
||
uint64_t saved_bset = 0;
|
||
#endif
|
||
uid_t saved_uid = getuid();
|
||
gid_t saved_gid = getgid();
|
||
uid_t uid = UID_INVALID;
|
||
gid_t gid = GID_INVALID;
|
||
size_t n_fds, /* fds to pass to the child */
|
||
n_keep_fds; /* total number of fds not to close */
|
||
int secure_bits;
|
||
_cleanup_free_ gid_t *gids_after_pam = NULL;
|
||
int ngids_after_pam = 0;
|
||
|
||
int socket_fd = -EBADF, named_iofds[3] = EBADF_TRIPLET;
|
||
size_t n_storage_fds, n_socket_fds, n_extra_fds;
|
||
|
||
assert(command);
|
||
assert(context);
|
||
assert(params);
|
||
assert(exit_status);
|
||
|
||
/* This should be mostly redundant, as the log level is also passed as an argument of the executor,
|
||
* and is already applied earlier. Just for safety. */
|
||
if (params->debug_invocation)
|
||
log_set_max_level(LOG_PRI(LOG_DEBUG));
|
||
else if (context->log_level_max >= 0)
|
||
log_set_max_level(context->log_level_max);
|
||
|
||
/* Explicitly test for CVE-2021-4034 inspired invocations */
|
||
if (!command->path || strv_isempty(command->argv)) {
|
||
*exit_status = EXIT_EXEC;
|
||
return log_exec_error_errno(
|
||
context,
|
||
params,
|
||
SYNTHETIC_ERRNO(EINVAL),
|
||
"Invalid command line arguments.");
|
||
}
|
||
|
||
LOG_CONTEXT_PUSH_EXEC(context, params);
|
||
|
||
if (context->std_input == EXEC_INPUT_SOCKET ||
|
||
context->std_output == EXEC_OUTPUT_SOCKET ||
|
||
context->std_error == EXEC_OUTPUT_SOCKET) {
|
||
|
||
if (params->n_socket_fds > 1)
|
||
return log_exec_error_errno(context, params, SYNTHETIC_ERRNO(EINVAL), "Got more than one socket.");
|
||
|
||
if (params->n_socket_fds == 0)
|
||
return log_exec_error_errno(context, params, SYNTHETIC_ERRNO(EINVAL), "Got no socket.");
|
||
|
||
socket_fd = params->fds[0];
|
||
n_storage_fds = n_socket_fds = n_extra_fds = 0;
|
||
} else {
|
||
n_socket_fds = params->n_socket_fds;
|
||
n_storage_fds = params->n_storage_fds;
|
||
n_extra_fds = params->n_extra_fds;
|
||
}
|
||
n_fds = n_socket_fds + n_storage_fds + n_extra_fds;
|
||
|
||
r = exec_context_named_iofds(context, params, named_iofds);
|
||
if (r < 0)
|
||
return log_exec_error_errno(context, params, r, "Failed to load a named file descriptor: %m");
|
||
|
||
rename_process_from_path(command->path);
|
||
|
||
/* We reset exactly these signals, since they are the only ones we set to SIG_IGN in the main
|
||
* daemon. All others we leave untouched because we set them to SIG_DFL or a valid handler initially,
|
||
* both of which will be demoted to SIG_DFL. */
|
||
(void) default_signals(SIGNALS_CRASH_HANDLER,
|
||
SIGNALS_IGNORE);
|
||
|
||
if (context->ignore_sigpipe)
|
||
(void) ignore_signals(SIGPIPE);
|
||
|
||
r = reset_signal_mask();
|
||
if (r < 0) {
|
||
*exit_status = EXIT_SIGNAL_MASK;
|
||
return log_exec_error_errno(context, params, r, "Failed to set process signal mask: %m");
|
||
}
|
||
|
||
if (params->idle_pipe)
|
||
do_idle_pipe_dance(params->idle_pipe);
|
||
|
||
/* Close fds we don't need very early to make sure we don't block init reexecution because it cannot bind its
|
||
* sockets. Among the fds we close are the logging fds, and we want to keep them closed, so that we don't have
|
||
* any fds open we don't really want open during the transition. In order to make logging work, we switch the
|
||
* log subsystem into open_when_needed mode, so that it reopens the logs on every single log call. */
|
||
|
||
log_forget_fds();
|
||
log_set_open_when_needed(true);
|
||
log_settle_target();
|
||
|
||
/* In case anything used libc syslog(), close this here, too */
|
||
closelog();
|
||
|
||
r = collect_open_file_fds(context, params, &n_fds);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_FDS;
|
||
return log_exec_error_errno(context, params, r, "Failed to get OpenFile= file descriptors: %m");
|
||
}
|
||
|
||
int keep_fds[n_fds + 4];
|
||
memcpy_safe(keep_fds, params->fds, n_fds * sizeof(int));
|
||
n_keep_fds = n_fds;
|
||
|
||
r = add_shifted_fd(keep_fds, ELEMENTSOF(keep_fds), &n_keep_fds, ¶ms->exec_fd);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_FDS;
|
||
return log_exec_error_errno(context, params, r, "Failed to collect shifted fd: %m");
|
||
}
|
||
|
||
r = add_shifted_fd(keep_fds, ELEMENTSOF(keep_fds), &n_keep_fds, ¶ms->handoff_timestamp_fd);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_FDS;
|
||
return log_exec_error_errno(context, params, r, "Failed to collect shifted fd: %m");
|
||
}
|
||
|
||
#if HAVE_LIBBPF
|
||
r = add_shifted_fd(keep_fds, ELEMENTSOF(keep_fds), &n_keep_fds, ¶ms->bpf_restrict_fs_map_fd);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_FDS;
|
||
return log_exec_error_errno(context, params, r, "Failed to collect shifted fd: %m");
|
||
}
|
||
#endif
|
||
|
||
r = close_remaining_fds(params, runtime, socket_fd, keep_fds, n_keep_fds);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_FDS;
|
||
return log_exec_error_errno(context, params, r, "Failed to close unwanted file descriptors: %m");
|
||
}
|
||
|
||
if (!context->same_pgrp &&
|
||
setsid() < 0) {
|
||
*exit_status = EXIT_SETSID;
|
||
return log_exec_error_errno(context, params, errno, "Failed to create new process session: %m");
|
||
}
|
||
|
||
/* Now, reset the TTY associated to this service "destructively" (i.e. possibly even hang up or
|
||
* disallocate the VT), to get rid of any prior uses of the device. Note that we do not keep any fd
|
||
* open here, hence some of the settings made here might vanish again, depending on the TTY driver
|
||
* used. A 2nd ("constructive") initialization after we opened the input/output fds we actually want
|
||
* will fix this. */
|
||
exec_context_tty_reset(context, params);
|
||
|
||
if (params->shall_confirm_spawn && exec_context_shall_confirm_spawn(context)) {
|
||
_cleanup_free_ char *cmdline = NULL;
|
||
|
||
cmdline = quote_command_line(command->argv, SHELL_ESCAPE_EMPTY);
|
||
if (!cmdline) {
|
||
*exit_status = EXIT_MEMORY;
|
||
return log_oom();
|
||
}
|
||
|
||
r = ask_for_confirmation(context, params, cmdline);
|
||
if (r != CONFIRM_EXECUTE) {
|
||
if (r == CONFIRM_PRETEND_SUCCESS) {
|
||
*exit_status = EXIT_SUCCESS;
|
||
return 0;
|
||
}
|
||
|
||
*exit_status = EXIT_CONFIRM;
|
||
return log_exec_error_errno(context, params, SYNTHETIC_ERRNO(ECANCELED),
|
||
"Execution cancelled by the user.");
|
||
}
|
||
}
|
||
|
||
/* We are about to invoke NSS and PAM modules. Let's tell them what we are doing here, maybe they care. This is
|
||
* used by nss-resolve to disable itself when we are about to start systemd-resolved, to avoid deadlocks. Note
|
||
* that these env vars do not survive the execve(), which means they really only apply to the PAM and NSS
|
||
* invocations themselves. Also note that while we'll only invoke NSS modules involved in user management they
|
||
* might internally call into other NSS modules that are involved in hostname resolution, we never know. */
|
||
if (setenv("SYSTEMD_ACTIVATION_UNIT", params->unit_id, true) != 0 ||
|
||
setenv("SYSTEMD_ACTIVATION_SCOPE", runtime_scope_to_string(params->runtime_scope), true) != 0) {
|
||
*exit_status = EXIT_MEMORY;
|
||
return log_exec_error_errno(context, params, errno, "Failed to update environment: %m");
|
||
}
|
||
|
||
if (context->dynamic_user && runtime && runtime->dynamic_creds) {
|
||
_cleanup_strv_free_ char **suggested_paths = NULL;
|
||
|
||
/* On top of that, make sure we bypass our own NSS module nss-systemd comprehensively for any NSS
|
||
* checks, if DynamicUser=1 is used, as we shouldn't create a feedback loop with ourselves here. */
|
||
if (putenv((char*) "SYSTEMD_NSS_DYNAMIC_BYPASS=1") != 0) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, errno, "Failed to update environment: %m");
|
||
}
|
||
|
||
r = compile_suggested_paths(context, params, &suggested_paths);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_MEMORY;
|
||
return log_oom();
|
||
}
|
||
|
||
r = dynamic_creds_realize(runtime->dynamic_creds, suggested_paths, &uid, &gid);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_USER;
|
||
if (r == -EILSEQ)
|
||
return log_exec_error_errno(context, params, SYNTHETIC_ERRNO(EOPNOTSUPP),
|
||
"Failed to update dynamic user credentials: User or group with specified name already exists.");
|
||
return log_exec_error_errno(context, params, r, "Failed to update dynamic user credentials: %m");
|
||
}
|
||
|
||
if (!uid_is_valid(uid)) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, SYNTHETIC_ERRNO(ESRCH), "UID validation failed for \""UID_FMT"\".", uid);
|
||
}
|
||
|
||
if (!gid_is_valid(gid)) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, SYNTHETIC_ERRNO(ESRCH), "GID validation failed for \""GID_FMT"\".", gid);
|
||
}
|
||
|
||
if (runtime->dynamic_creds->user)
|
||
username = runtime->dynamic_creds->user->name;
|
||
|
||
} else {
|
||
const char *u;
|
||
|
||
if (context->user)
|
||
u = context->user;
|
||
else if (context->pam_name) {
|
||
/* If PAM is enabled but no user name is explicitly selected, then use our own one. */
|
||
own_user = getusername_malloc();
|
||
if (!own_user) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, r, "Failed to determine my own user ID: %m");
|
||
}
|
||
u = own_user;
|
||
} else
|
||
u = NULL;
|
||
|
||
if (u) {
|
||
r = get_fixed_user(u, &username, &uid, &gid, &home, &shell);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, r, "Failed to determine user credentials: %m");
|
||
}
|
||
}
|
||
|
||
if (context->group) {
|
||
r = get_fixed_group(context->group, &groupname, &gid);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_GROUP;
|
||
return log_exec_error_errno(context, params, r, "Failed to determine group credentials: %m");
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Initialize user supplementary groups and get SupplementaryGroups= ones */
|
||
r = get_supplementary_groups(context, username, groupname, gid,
|
||
&supplementary_gids, &ngids);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_GROUP;
|
||
return log_exec_error_errno(context, params, r, "Failed to determine supplementary groups: %m");
|
||
}
|
||
|
||
r = send_user_lookup(params->unit_id, params->user_lookup_fd, uid, gid);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, r, "Failed to send user credentials to PID1: %m");
|
||
}
|
||
|
||
params->user_lookup_fd = safe_close(params->user_lookup_fd);
|
||
|
||
r = acquire_home(context, &home, &home_buffer);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_CHDIR;
|
||
return log_exec_error_errno(context, params, r, "Failed to determine $HOME for the invoking user: %m");
|
||
}
|
||
|
||
/* If a socket is connected to STDIN/STDOUT/STDERR, we must drop O_NONBLOCK */
|
||
if (socket_fd >= 0)
|
||
(void) fd_nonblock(socket_fd, false);
|
||
|
||
/* Journald will try to look-up our cgroup in order to populate _SYSTEMD_CGROUP and _SYSTEMD_UNIT fields.
|
||
* Hence we need to migrate to the target cgroup from init.scope before connecting to journald */
|
||
if (params->cgroup_path) {
|
||
_cleanup_free_ char *p = NULL;
|
||
|
||
r = exec_params_get_cgroup_path(params, cgroup_context, &p);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_CGROUP;
|
||
return log_exec_error_errno(context, params, r, "Failed to acquire cgroup path: %m");
|
||
}
|
||
|
||
r = cg_attach_everywhere(params->cgroup_supported, p, 0);
|
||
if (r == -EUCLEAN) {
|
||
*exit_status = EXIT_CGROUP;
|
||
return log_exec_error_errno(context, params, r,
|
||
"Failed to attach process to cgroup '%s', "
|
||
"because the cgroup or one of its parents or "
|
||
"siblings is in the threaded mode.", p);
|
||
}
|
||
if (r < 0) {
|
||
*exit_status = EXIT_CGROUP;
|
||
return log_exec_error_errno(context, params, r, "Failed to attach to cgroup %s: %m", p);
|
||
}
|
||
}
|
||
|
||
if (context->network_namespace_path && runtime && runtime->shared && runtime->shared->netns_storage_socket[0] >= 0) {
|
||
r = open_shareable_ns_path(runtime->shared->netns_storage_socket, context->network_namespace_path, CLONE_NEWNET);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_NETWORK;
|
||
return log_exec_error_errno(context, params, r, "Failed to open network namespace path %s: %m", context->network_namespace_path);
|
||
}
|
||
}
|
||
|
||
if (context->ipc_namespace_path && runtime && runtime->shared && runtime->shared->ipcns_storage_socket[0] >= 0) {
|
||
r = open_shareable_ns_path(runtime->shared->ipcns_storage_socket, context->ipc_namespace_path, CLONE_NEWIPC);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_NAMESPACE;
|
||
return log_exec_error_errno(context, params, r, "Failed to open IPC namespace path %s: %m", context->ipc_namespace_path);
|
||
}
|
||
}
|
||
|
||
r = setup_input(context, params, socket_fd, named_iofds);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_STDIN;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up standard input: %m");
|
||
}
|
||
|
||
_cleanup_free_ char *fname = NULL;
|
||
r = path_extract_filename(command->path, &fname);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_STDOUT;
|
||
return log_exec_error_errno(context, params, r, "Failed to extract filename from path %s: %m", command->path);
|
||
}
|
||
|
||
r = setup_output(context, params, STDOUT_FILENO, socket_fd, named_iofds, fname, uid, gid, &journal_stream_dev, &journal_stream_ino);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_STDOUT;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up standard output: %m");
|
||
}
|
||
|
||
r = setup_output(context, params, STDERR_FILENO, socket_fd, named_iofds, fname, uid, gid, &journal_stream_dev, &journal_stream_ino);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_STDERR;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up standard error output: %m");
|
||
}
|
||
|
||
/* Now that stdin/stdout are definiely opened, properly initialize it with our desired
|
||
* settings. Note: this is a "constructive" reset, it prepares things for us to use. This is
|
||
* different from the "destructive" TTY reset further up. Also note: we apply this on stdin/stdout in
|
||
* case this is a tty, regardless if we opened it ourselves or got it passed in pre-opened. */
|
||
prepare_terminal(context, params);
|
||
|
||
if (context->oom_score_adjust_set) {
|
||
/* When we can't make this change due to EPERM, then let's silently skip over it. User
|
||
* namespaces prohibit write access to this file, and we shouldn't trip up over that. */
|
||
r = set_oom_score_adjust(context->oom_score_adjust);
|
||
if (ERRNO_IS_NEG_PRIVILEGE(r))
|
||
log_exec_debug_errno(context, params, r,
|
||
"Failed to adjust OOM setting, assuming containerized execution, ignoring: %m");
|
||
else if (r < 0) {
|
||
*exit_status = EXIT_OOM_ADJUST;
|
||
return log_exec_error_errno(context, params, r, "Failed to adjust OOM setting: %m");
|
||
}
|
||
}
|
||
|
||
if (context->coredump_filter_set) {
|
||
r = set_coredump_filter(context->coredump_filter);
|
||
if (ERRNO_IS_NEG_PRIVILEGE(r))
|
||
log_exec_debug_errno(context, params, r, "Failed to adjust coredump_filter, ignoring: %m");
|
||
else if (r < 0) {
|
||
*exit_status = EXIT_LIMITS;
|
||
return log_exec_error_errno(context, params, r, "Failed to adjust coredump_filter: %m");
|
||
}
|
||
}
|
||
|
||
if (context->cpu_sched_set) {
|
||
struct sched_attr attr = {
|
||
.size = sizeof(attr),
|
||
.sched_policy = context->cpu_sched_policy,
|
||
.sched_priority = context->cpu_sched_priority,
|
||
.sched_flags = context->cpu_sched_reset_on_fork ? SCHED_FLAG_RESET_ON_FORK : 0,
|
||
};
|
||
|
||
r = sched_setattr(/* pid= */ 0, &attr, /* flags= */ 0);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_SETSCHEDULER;
|
||
return log_exec_error_errno(context, params, errno, "Failed to set up CPU scheduling: %m");
|
||
}
|
||
}
|
||
|
||
/*
|
||
* Set nice value _after_ the call to sched_setattr() because struct sched_attr includes sched_nice
|
||
* which we do not set, thus it will clobber any previously set nice value. Scheduling policy might
|
||
* be reasonably set together with nice value e.g. in case of SCHED_BATCH (see sched(7)).
|
||
* It would be ideal to set both with the same call, but we cannot easily do so because of all the
|
||
* extra logic in setpriority_closest().
|
||
*/
|
||
if (context->nice_set) {
|
||
r = setpriority_closest(context->nice);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_NICE;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up process scheduling priority (nice level): %m");
|
||
}
|
||
}
|
||
|
||
if (context->cpu_affinity_from_numa || context->cpu_set.set) {
|
||
_cleanup_(cpu_set_reset) CPUSet converted_cpu_set = {};
|
||
const CPUSet *cpu_set;
|
||
|
||
if (context->cpu_affinity_from_numa) {
|
||
r = exec_context_cpu_affinity_from_numa(context, &converted_cpu_set);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_CPUAFFINITY;
|
||
return log_exec_error_errno(context, params, r, "Failed to derive CPU affinity mask from NUMA mask: %m");
|
||
}
|
||
|
||
cpu_set = &converted_cpu_set;
|
||
} else
|
||
cpu_set = &context->cpu_set;
|
||
|
||
if (sched_setaffinity(0, cpu_set->allocated, cpu_set->set) < 0) {
|
||
*exit_status = EXIT_CPUAFFINITY;
|
||
return log_exec_error_errno(context, params, errno, "Failed to set up CPU affinity: %m");
|
||
}
|
||
}
|
||
|
||
if (mpol_is_valid(numa_policy_get_type(&context->numa_policy))) {
|
||
r = apply_numa_policy(&context->numa_policy);
|
||
if (ERRNO_IS_NEG_NOT_SUPPORTED(r))
|
||
log_exec_debug_errno(context, params, r, "NUMA support not available, ignoring.");
|
||
else if (r < 0) {
|
||
*exit_status = EXIT_NUMA_POLICY;
|
||
return log_exec_error_errno(context, params, r, "Failed to set NUMA memory policy: %m");
|
||
}
|
||
}
|
||
|
||
if (context->ioprio_set)
|
||
if (ioprio_set(IOPRIO_WHO_PROCESS, 0, context->ioprio) < 0) {
|
||
*exit_status = EXIT_IOPRIO;
|
||
return log_exec_error_errno(context, params, errno, "Failed to set up IO scheduling priority: %m");
|
||
}
|
||
|
||
if (context->timer_slack_nsec != NSEC_INFINITY)
|
||
if (prctl(PR_SET_TIMERSLACK, context->timer_slack_nsec) < 0) {
|
||
*exit_status = EXIT_TIMERSLACK;
|
||
return log_exec_error_errno(context, params, errno, "Failed to set up timer slack: %m");
|
||
}
|
||
|
||
if (context->personality != PERSONALITY_INVALID) {
|
||
r = safe_personality(context->personality);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_PERSONALITY;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up execution domain (personality): %m");
|
||
}
|
||
}
|
||
|
||
#if ENABLE_UTMP
|
||
if (context->utmp_id) {
|
||
_cleanup_free_ char *username_alloc = NULL;
|
||
|
||
if (!username && context->utmp_mode == EXEC_UTMP_USER) {
|
||
username_alloc = uid_to_name(uid_is_valid(uid) ? uid : saved_uid);
|
||
if (!username_alloc) {
|
||
*exit_status = EXIT_USER;
|
||
return log_oom();
|
||
}
|
||
}
|
||
|
||
const char *line = context->tty_path ?
|
||
(path_startswith(context->tty_path, "/dev/") ?: context->tty_path) :
|
||
NULL;
|
||
utmp_put_init_process(context->utmp_id, getpid_cached(), getsid(0),
|
||
line,
|
||
context->utmp_mode == EXEC_UTMP_INIT ? INIT_PROCESS :
|
||
context->utmp_mode == EXEC_UTMP_LOGIN ? LOGIN_PROCESS :
|
||
USER_PROCESS,
|
||
username ?: username_alloc);
|
||
}
|
||
#endif
|
||
|
||
if (uid_is_valid(uid)) {
|
||
r = chown_terminal(STDIN_FILENO, uid);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_STDIN;
|
||
return log_exec_error_errno(context, params, r, "Failed to change ownership of terminal: %m");
|
||
}
|
||
}
|
||
|
||
/* We need sandboxing if the caller asked us to apply it and the command isn't explicitly excepted
|
||
* from it. */
|
||
needs_sandboxing = (params->flags & EXEC_APPLY_SANDBOXING) && !(command->flags & EXEC_COMMAND_FULLY_PRIVILEGED);
|
||
|
||
if (params->cgroup_path) {
|
||
/* If delegation is enabled we'll pass ownership of the cgroup to the user of the new process. On cgroup v1
|
||
* this is only about systemd's own hierarchy, i.e. not the controller hierarchies, simply because that's not
|
||
* safe. On cgroup v2 there's only one hierarchy anyway, and delegation is safe there, hence in that case only
|
||
* touch a single hierarchy too. */
|
||
|
||
if (params->flags & EXEC_CGROUP_DELEGATE) {
|
||
_cleanup_free_ char *p = NULL;
|
||
|
||
r = cg_set_access(SYSTEMD_CGROUP_CONTROLLER, params->cgroup_path, uid, gid);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_CGROUP;
|
||
return log_exec_error_errno(context, params, r, "Failed to adjust control group access: %m");
|
||
}
|
||
|
||
r = exec_params_get_cgroup_path(params, cgroup_context, &p);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_CGROUP;
|
||
return log_exec_error_errno(context, params, r, "Failed to acquire cgroup path: %m");
|
||
}
|
||
if (r > 0) {
|
||
r = cg_set_access_recursive(SYSTEMD_CGROUP_CONTROLLER, p, uid, gid);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_CGROUP;
|
||
return log_exec_error_errno(context, params, r, "Failed to adjust control subgroup access: %m");
|
||
}
|
||
}
|
||
}
|
||
|
||
if (cgroup_context && cg_unified() > 0 && is_pressure_supported() > 0) {
|
||
if (cgroup_context_want_memory_pressure(cgroup_context)) {
|
||
r = cg_get_path("memory", params->cgroup_path, "memory.pressure", &memory_pressure_path);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_MEMORY;
|
||
return log_oom();
|
||
}
|
||
|
||
r = chmod_and_chown(memory_pressure_path, 0644, uid, gid);
|
||
if (r < 0) {
|
||
log_exec_full_errno(context, params, r == -ENOENT || ERRNO_IS_PRIVILEGE(r) ? LOG_DEBUG : LOG_WARNING, r,
|
||
"Failed to adjust ownership of '%s', ignoring: %m", memory_pressure_path);
|
||
memory_pressure_path = mfree(memory_pressure_path);
|
||
}
|
||
/* First we use the current cgroup path to chmod and chown the memory pressure path, then pass the path relative
|
||
* to the cgroup namespace to environment variables and mounts. If chown/chmod fails, we should not pass memory
|
||
* pressure path environment variable or read-write mount to the unit. This is why we check if
|
||
* memory_pressure_path != NULL in the conditional below. */
|
||
if (memory_pressure_path && needs_sandboxing && exec_needs_cgroup_namespace(context, params)) {
|
||
memory_pressure_path = mfree(memory_pressure_path);
|
||
r = cg_get_path("memory", "", "memory.pressure", &memory_pressure_path);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_MEMORY;
|
||
return log_oom();
|
||
}
|
||
}
|
||
} else if (cgroup_context->memory_pressure_watch == CGROUP_PRESSURE_WATCH_NO) {
|
||
memory_pressure_path = strdup("/dev/null"); /* /dev/null is explicit indicator for turning of memory pressure watch */
|
||
if (!memory_pressure_path) {
|
||
*exit_status = EXIT_MEMORY;
|
||
return log_oom();
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
needs_mount_namespace = exec_needs_mount_namespace(context, params, runtime);
|
||
|
||
for (ExecDirectoryType dt = 0; dt < _EXEC_DIRECTORY_TYPE_MAX; dt++) {
|
||
r = setup_exec_directory(context, params, uid, gid, dt, needs_mount_namespace, exit_status);
|
||
if (r < 0)
|
||
return log_exec_error_errno(context, params, r, "Failed to set up special execution directory in %s: %m", params->prefix[dt]);
|
||
}
|
||
|
||
r = exec_setup_credentials(context, params, params->unit_id, uid, gid);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_CREDENTIALS;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up credentials: %m");
|
||
}
|
||
|
||
r = build_environment(
|
||
context,
|
||
params,
|
||
cgroup_context,
|
||
n_fds,
|
||
home,
|
||
username,
|
||
shell,
|
||
journal_stream_dev,
|
||
journal_stream_ino,
|
||
memory_pressure_path,
|
||
needs_sandboxing,
|
||
&our_env);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_MEMORY;
|
||
return log_oom();
|
||
}
|
||
|
||
r = build_pass_environment(context, &pass_env);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_MEMORY;
|
||
return log_oom();
|
||
}
|
||
|
||
/* The $PATH variable is set to the default path in params->environment. However, this is overridden
|
||
* if user-specified fields have $PATH set. The intention is to also override $PATH if the unit does
|
||
* not specify PATH but the unit has ExecSearchPath. */
|
||
if (!strv_isempty(context->exec_search_path)) {
|
||
_cleanup_free_ char *joined = NULL;
|
||
|
||
joined = strv_join(context->exec_search_path, ":");
|
||
if (!joined) {
|
||
*exit_status = EXIT_MEMORY;
|
||
return log_oom();
|
||
}
|
||
|
||
r = strv_env_assign(&joined_exec_search_path, "PATH", joined);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_MEMORY;
|
||
return log_oom();
|
||
}
|
||
}
|
||
|
||
accum_env = strv_env_merge(params->environment,
|
||
our_env,
|
||
joined_exec_search_path,
|
||
pass_env,
|
||
context->environment,
|
||
params->files_env);
|
||
if (!accum_env) {
|
||
*exit_status = EXIT_MEMORY;
|
||
return log_oom();
|
||
}
|
||
accum_env = strv_env_clean(accum_env);
|
||
|
||
(void) umask(context->umask);
|
||
|
||
r = setup_keyring(context, params, uid, gid);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_KEYRING;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up kernel keyring: %m");
|
||
}
|
||
|
||
/* We need setresuid() if the caller asked us to apply sandboxing and the command isn't explicitly
|
||
* excepted from either whole sandboxing or just setresuid() itself. */
|
||
needs_setuid = (params->flags & EXEC_APPLY_SANDBOXING) && !(command->flags & (EXEC_COMMAND_FULLY_PRIVILEGED|EXEC_COMMAND_NO_SETUID));
|
||
|
||
uint64_t capability_ambient_set = context->capability_ambient_set;
|
||
|
||
/* Check CAP_SYS_ADMIN before we enter user namespace to see if we can mount /proc even though its masked. */
|
||
has_cap_sys_admin = have_effective_cap(CAP_SYS_ADMIN) > 0;
|
||
|
||
if (needs_sandboxing) {
|
||
/* MAC enablement checks need to be done before a new mount ns is created, as they rely on
|
||
* /sys being present. The actual MAC context application will happen later, as late as
|
||
* possible, to avoid impacting our own code paths. */
|
||
|
||
#if HAVE_SELINUX
|
||
use_selinux = mac_selinux_use();
|
||
#endif
|
||
#if ENABLE_SMACK
|
||
use_smack = mac_smack_use();
|
||
#endif
|
||
#if HAVE_APPARMOR
|
||
use_apparmor = mac_apparmor_use();
|
||
#endif
|
||
}
|
||
|
||
if (needs_sandboxing) {
|
||
int which_failed;
|
||
|
||
/* Let's set the resource limits before we call into PAM, so that pam_limits wins over what
|
||
* is set here. (See below.) */
|
||
|
||
r = setrlimit_closest_all((const struct rlimit* const *) context->rlimit, &which_failed);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_LIMITS;
|
||
return log_exec_error_errno(context, params, r, "Failed to adjust resource limit RLIMIT_%s: %m", rlimit_to_string(which_failed));
|
||
}
|
||
}
|
||
|
||
if (needs_setuid && context->pam_name && username) {
|
||
/* Let's call into PAM after we set up our own idea of resource limits so that pam_limits
|
||
* wins here. (See above.) */
|
||
|
||
/* All fds passed in the fds array will be closed in the pam child process. */
|
||
r = setup_pam(context->pam_name, username, uid, gid, context->tty_path, &accum_env, params->fds, n_fds, params->exec_fd);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_PAM;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up PAM session: %m");
|
||
}
|
||
|
||
/* PAM modules might have set some ambient caps. Query them here and merge them into
|
||
* the caps we want to set in the end, so that we don't end up unsetting them. */
|
||
uint64_t ambient_after_pam;
|
||
r = capability_get_ambient(&ambient_after_pam);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_CAPABILITIES;
|
||
return log_exec_error_errno(context, params, r, "Failed to query ambient caps: %m");
|
||
}
|
||
|
||
capability_ambient_set |= ambient_after_pam;
|
||
|
||
ngids_after_pam = getgroups_alloc(&gids_after_pam);
|
||
if (ngids_after_pam < 0) {
|
||
*exit_status = EXIT_GROUP;
|
||
return log_exec_error_errno(context, params, ngids_after_pam, "Failed to obtain groups after setting up PAM: %m");
|
||
}
|
||
}
|
||
|
||
if (needs_sandboxing && exec_context_need_unprivileged_private_users(context, params)) {
|
||
/* If we're unprivileged, set up the user namespace first to enable use of the other namespaces.
|
||
* Users with CAP_SYS_ADMIN can set up user namespaces last because they will be able to
|
||
* set up all of the other namespaces (i.e. network, mount, UTS) without a user namespace. */
|
||
PrivateUsers pu = context->private_users;
|
||
if (pu == PRIVATE_USERS_NO)
|
||
pu = PRIVATE_USERS_SELF;
|
||
|
||
/* The kernel requires /proc/pid/setgroups be set to "deny" prior to writing /proc/pid/gid_map in
|
||
* unprivileged user namespaces. */
|
||
r = setup_private_users(pu, saved_uid, saved_gid, uid, gid, /* allow_setgroups= */ false);
|
||
/* If it was requested explicitly and we can't set it up, fail early. Otherwise, continue and let
|
||
* the actual requested operations fail (or silently continue). */
|
||
if (r < 0 && context->private_users != PRIVATE_USERS_NO) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up user namespacing for unprivileged user: %m");
|
||
}
|
||
if (r < 0)
|
||
log_exec_info_errno(context, params, r, "Failed to set up user namespacing for unprivileged user, ignoring: %m");
|
||
else {
|
||
assert(r > 0);
|
||
userns_set_up = true;
|
||
}
|
||
}
|
||
|
||
if (exec_needs_network_namespace(context) && runtime && runtime->shared && runtime->shared->netns_storage_socket[0] >= 0) {
|
||
|
||
/* Try to enable network namespacing if network namespacing is available and we have
|
||
* CAP_NET_ADMIN. We need CAP_NET_ADMIN to be able to configure the loopback device in the
|
||
* new network namespace. And if we don't have that, then we could only create a network
|
||
* namespace without the ability to set up "lo". Hence gracefully skip things then. */
|
||
if (ns_type_supported(NAMESPACE_NET) && have_effective_cap(CAP_NET_ADMIN) > 0) {
|
||
r = setup_shareable_ns(runtime->shared->netns_storage_socket, CLONE_NEWNET);
|
||
if (ERRNO_IS_NEG_PRIVILEGE(r))
|
||
log_exec_notice_errno(context, params, r,
|
||
"PrivateNetwork=yes is configured, but network namespace setup not permitted, proceeding without: %m");
|
||
else if (r < 0) {
|
||
*exit_status = EXIT_NETWORK;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up network namespacing: %m");
|
||
}
|
||
} else if (context->network_namespace_path) {
|
||
*exit_status = EXIT_NETWORK;
|
||
return log_exec_error_errno(context, params, SYNTHETIC_ERRNO(EOPNOTSUPP),
|
||
"NetworkNamespacePath= is not supported, refusing.");
|
||
} else
|
||
log_exec_notice(context, params, "PrivateNetwork=yes is configured, but the kernel does not support or we lack privileges for network namespace, proceeding without.");
|
||
}
|
||
|
||
if (exec_needs_ipc_namespace(context) && runtime && runtime->shared && runtime->shared->ipcns_storage_socket[0] >= 0) {
|
||
|
||
if (ns_type_supported(NAMESPACE_IPC)) {
|
||
r = setup_shareable_ns(runtime->shared->ipcns_storage_socket, CLONE_NEWIPC);
|
||
if (ERRNO_IS_NEG_PRIVILEGE(r))
|
||
log_exec_warning_errno(context, params, r,
|
||
"PrivateIPC=yes is configured, but IPC namespace setup failed, ignoring: %m");
|
||
else if (r < 0) {
|
||
*exit_status = EXIT_NAMESPACE;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up IPC namespacing: %m");
|
||
}
|
||
} else if (context->ipc_namespace_path) {
|
||
*exit_status = EXIT_NAMESPACE;
|
||
return log_exec_error_errno(context, params, SYNTHETIC_ERRNO(EOPNOTSUPP),
|
||
"IPCNamespacePath= is not supported, refusing.");
|
||
} else
|
||
log_exec_warning(context, params, "PrivateIPC=yes is configured, but the kernel does not support IPC namespaces, ignoring.");
|
||
}
|
||
|
||
if (needs_sandboxing && exec_needs_cgroup_namespace(context, params)) {
|
||
r = unshare(CLONE_NEWCGROUP);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_NAMESPACE;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up cgroup namespacing: %m");
|
||
}
|
||
}
|
||
|
||
/* Unshare a new PID namespace before setting up mounts to ensure /proc/ is mounted with only processes in PID namespace visible.
|
||
* Note PrivatePIDs=yes implies MountAPIVFS=yes so we'll always ensure procfs is remounted. */
|
||
if (needs_sandboxing && exec_needs_pid_namespace(context)) {
|
||
if (params->pidref_transport_fd < 0) {
|
||
*exit_status = EXIT_NAMESPACE;
|
||
return log_exec_error_errno(context, params, r, "PidRef socket is not set up: %m");
|
||
}
|
||
|
||
/* If we had CAP_SYS_ADMIN prior to joining the user namespace, then we are privileged and don't need
|
||
* to check if we can mount /proc/.
|
||
*
|
||
* We need to check prior to entering the user namespace because if we're running unprivileged or in a
|
||
* system without CAP_SYS_ADMIN, then we can have CAP_SYS_ADMIN in the current user namespace but not
|
||
* once we unshare a mount namespace. */
|
||
r = has_cap_sys_admin ? 1 : can_mount_proc(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_NAMESPACE;
|
||
return log_exec_error_errno(context, params, r, "Failed to detect if /proc/ can be remounted: %m");
|
||
}
|
||
if (r == 0) {
|
||
*exit_status = EXIT_NAMESPACE;
|
||
return log_exec_error_errno(context, params, SYNTHETIC_ERRNO(EPERM),
|
||
"PrivatePIDs=yes is configured, but /proc/ cannot be re-mounted due to lack of privileges, refusing.");
|
||
}
|
||
|
||
r = setup_private_pids(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_NAMESPACE;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up pid namespace: %m");
|
||
}
|
||
}
|
||
|
||
/* If PrivatePIDs= yes is configured, we're now running as pid 1 in a pid namespace! */
|
||
|
||
if (needs_mount_namespace) {
|
||
_cleanup_free_ char *error_path = NULL;
|
||
|
||
r = apply_mount_namespace(command->flags,
|
||
context,
|
||
params,
|
||
runtime,
|
||
memory_pressure_path,
|
||
needs_sandboxing,
|
||
&error_path,
|
||
uid,
|
||
gid);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_NAMESPACE;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up mount namespacing%s%s: %m",
|
||
error_path ? ": " : "", strempty(error_path));
|
||
}
|
||
}
|
||
|
||
if (needs_sandboxing) {
|
||
r = apply_protect_hostname(context, params, exit_status);
|
||
if (r < 0)
|
||
return r;
|
||
}
|
||
|
||
if (context->memory_ksm >= 0)
|
||
if (prctl(PR_SET_MEMORY_MERGE, context->memory_ksm, 0, 0, 0) < 0) {
|
||
if (ERRNO_IS_NOT_SUPPORTED(errno))
|
||
log_exec_debug_errno(context,
|
||
params,
|
||
errno,
|
||
"KSM support not available, ignoring.");
|
||
else {
|
||
*exit_status = EXIT_KSM;
|
||
return log_exec_error_errno(context, params, errno, "Failed to set KSM: %m");
|
||
}
|
||
}
|
||
|
||
/* Drop groups as early as possible.
|
||
* This needs to be done after PrivateDevices=yes setup as device nodes should be owned by the host's root.
|
||
* For non-root in a userns, devices will be owned by the user/group before the group change, and nobody. */
|
||
if (needs_setuid) {
|
||
_cleanup_free_ gid_t *gids_to_enforce = NULL;
|
||
int ngids_to_enforce = 0;
|
||
|
||
ngids_to_enforce = merge_gid_lists(supplementary_gids,
|
||
ngids,
|
||
gids_after_pam,
|
||
ngids_after_pam,
|
||
&gids_to_enforce);
|
||
if (ngids_to_enforce < 0) {
|
||
*exit_status = EXIT_GROUP;
|
||
return log_exec_error_errno(context, params,
|
||
ngids_to_enforce,
|
||
"Failed to merge group lists. Group membership might be incorrect: %m");
|
||
}
|
||
|
||
r = enforce_groups(gid, gids_to_enforce, ngids_to_enforce);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_GROUP;
|
||
return log_exec_error_errno(context, params, r, "Changing group credentials failed: %m");
|
||
}
|
||
}
|
||
|
||
/* If the user namespace was not set up above, try to do it now.
|
||
* It's preferred to set up the user namespace later (after all other namespaces) so as not to be
|
||
* restricted by rules pertaining to combining user namespaces with other namespaces (e.g. in the
|
||
* case of mount namespaces being less privileged when the mount point list is copied from a
|
||
* different user namespace). */
|
||
|
||
if (needs_sandboxing && !userns_set_up) {
|
||
r = setup_private_users(context->private_users, saved_uid, saved_gid, uid, gid,
|
||
/* allow_setgroups= */ context->private_users == PRIVATE_USERS_FULL);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up user namespacing: %m");
|
||
}
|
||
}
|
||
|
||
/* Now that the mount namespace has been set up and privileges adjusted, let's look for the thing we
|
||
* shall execute. */
|
||
|
||
_cleanup_free_ char *executable = NULL;
|
||
_cleanup_close_ int executable_fd = -EBADF;
|
||
r = find_executable_full(command->path, /* root= */ NULL, context->exec_search_path, false, &executable, &executable_fd);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_EXEC;
|
||
log_exec_struct_errno(context, params, LOG_NOTICE, r,
|
||
"MESSAGE_ID=" SD_MESSAGE_SPAWN_FAILED_STR,
|
||
LOG_EXEC_MESSAGE(params,
|
||
"Unable to locate executable '%s': %m",
|
||
command->path),
|
||
"EXECUTABLE=%s", command->path);
|
||
/* If the error will be ignored by manager, tune down the log level here. Missing executable
|
||
* is very much expected in this case. */
|
||
return r != -ENOMEM && FLAGS_SET(command->flags, EXEC_COMMAND_IGNORE_FAILURE) ? 1 : r;
|
||
}
|
||
|
||
r = add_shifted_fd(keep_fds, ELEMENTSOF(keep_fds), &n_keep_fds, &executable_fd);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_FDS;
|
||
return log_exec_error_errno(context, params, r, "Failed to collect shifted fd: %m");
|
||
}
|
||
|
||
#if HAVE_SELINUX
|
||
if (needs_sandboxing && use_selinux && params->selinux_context_net) {
|
||
int fd = -EBADF;
|
||
|
||
if (socket_fd >= 0)
|
||
fd = socket_fd;
|
||
else if (params->n_socket_fds == 1)
|
||
/* If stdin is not connected to a socket but we are triggered by exactly one socket unit then we
|
||
* use context from that fd to compute the label. */
|
||
fd = params->fds[0];
|
||
|
||
if (fd >= 0) {
|
||
r = mac_selinux_get_child_mls_label(fd, executable, context->selinux_context, &mac_selinux_context_net);
|
||
if (r < 0) {
|
||
if (!context->selinux_context_ignore) {
|
||
*exit_status = EXIT_SELINUX_CONTEXT;
|
||
return log_exec_error_errno(context,
|
||
params,
|
||
r,
|
||
"Failed to determine SELinux context: %m");
|
||
}
|
||
log_exec_debug_errno(context,
|
||
params,
|
||
r,
|
||
"Failed to determine SELinux context, ignoring: %m");
|
||
}
|
||
}
|
||
}
|
||
#endif
|
||
|
||
/* We repeat the fd closing here, to make sure that nothing is leaked from the PAM modules. Note that
|
||
* we are more aggressive this time, since we don't need socket_fd and the netns and ipcns fds any
|
||
* more. We do keep exec_fd and handoff_timestamp_fd however, if we have it, since we need to keep
|
||
* them open until the final execve(). But first, close the remaining sockets in the context
|
||
* objects. */
|
||
|
||
exec_runtime_close(runtime);
|
||
exec_params_close(params);
|
||
|
||
r = close_all_fds(keep_fds, n_keep_fds);
|
||
if (r >= 0)
|
||
r = pack_fds(params->fds, n_fds);
|
||
if (r >= 0)
|
||
r = flag_fds(params->fds, n_socket_fds, n_fds, context->non_blocking);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_FDS;
|
||
return log_exec_error_errno(context, params, r, "Failed to adjust passed file descriptors: %m");
|
||
}
|
||
|
||
/* At this point, the fds we want to pass to the program are all ready and set up, with O_CLOEXEC turned off
|
||
* and at the right fd numbers. The are no other fds open, with one exception: the exec_fd if it is defined,
|
||
* and it has O_CLOEXEC set, after all we want it to be closed by the execve(), so that our parent knows we
|
||
* came this far. */
|
||
|
||
secure_bits = context->secure_bits;
|
||
|
||
if (needs_sandboxing) {
|
||
uint64_t bset;
|
||
|
||
/* Set the RTPRIO resource limit to 0, but only if nothing else was explicitly requested.
|
||
* (Note this is placed after the general resource limit initialization, see above, in order
|
||
* to take precedence.) */
|
||
if (context->restrict_realtime && !context->rlimit[RLIMIT_RTPRIO]) {
|
||
if (setrlimit(RLIMIT_RTPRIO, &RLIMIT_MAKE_CONST(0)) < 0) {
|
||
*exit_status = EXIT_LIMITS;
|
||
return log_exec_error_errno(context, params, errno, "Failed to adjust RLIMIT_RTPRIO resource limit: %m");
|
||
}
|
||
}
|
||
|
||
#if ENABLE_SMACK
|
||
/* LSM Smack needs the capability CAP_MAC_ADMIN to change the current execution security context of the
|
||
* process. This is the latest place before dropping capabilities. Other MAC context are set later. */
|
||
if (use_smack) {
|
||
r = setup_smack(params, context, executable_fd);
|
||
if (r < 0 && !context->smack_process_label_ignore) {
|
||
*exit_status = EXIT_SMACK_PROCESS_LABEL;
|
||
return log_exec_error_errno(context, params, r, "Failed to set SMACK process label: %m");
|
||
}
|
||
}
|
||
#endif
|
||
|
||
bset = context->capability_bounding_set;
|
||
|
||
#if HAVE_SECCOMP
|
||
/* If the service has any form of a seccomp filter and it allows dropping privileges, we'll
|
||
* keep the needed privileges to apply it even if we're not root. */
|
||
if (needs_setuid &&
|
||
uid_is_valid(uid) &&
|
||
context_has_seccomp(context) &&
|
||
seccomp_allows_drop_privileges(context)) {
|
||
keep_seccomp_privileges = true;
|
||
|
||
if (prctl(PR_SET_KEEPCAPS, 1) < 0) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, errno, "Failed to enable keep capabilities flag: %m");
|
||
}
|
||
|
||
/* Save the current bounding set so we can restore it after applying the seccomp
|
||
* filter */
|
||
saved_bset = bset;
|
||
bset |= (UINT64_C(1) << CAP_SYS_ADMIN) |
|
||
(UINT64_C(1) << CAP_SETPCAP);
|
||
}
|
||
#endif
|
||
|
||
if (!cap_test_all(bset)) {
|
||
r = capability_bounding_set_drop(bset, /* right_now= */ false);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_CAPABILITIES;
|
||
return log_exec_error_errno(context, params, r, "Failed to drop capabilities: %m");
|
||
}
|
||
}
|
||
|
||
/* Ambient capabilities are cleared during setresuid() (in enforce_user()) even with
|
||
* keep-caps set.
|
||
*
|
||
* To be able to raise the ambient capabilities after setresuid() they have to be added to
|
||
* the inherited set and keep caps has to be set (done in enforce_user()). After setresuid()
|
||
* the ambient capabilities can be raised as they are present in the permitted and
|
||
* inhertiable set. However it is possible that someone wants to set ambient capabilities
|
||
* without changing the user, so we also set the ambient capabilities here.
|
||
*
|
||
* The requested ambient capabilities are raised in the inheritable set if the second
|
||
* argument is true. */
|
||
if (capability_ambient_set != 0) {
|
||
r = capability_ambient_set_apply(capability_ambient_set, /* also_inherit= */ true);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_CAPABILITIES;
|
||
return log_exec_error_errno(context, params, r, "Failed to apply ambient capabilities (before UID change): %m");
|
||
}
|
||
}
|
||
}
|
||
|
||
/* chroot to root directory first, before we lose the ability to chroot */
|
||
r = apply_root_directory(context, params, runtime, needs_mount_namespace, exit_status);
|
||
if (r < 0)
|
||
return log_exec_error_errno(context, params, r, "Chrooting to the requested root directory failed: %m");
|
||
|
||
if (needs_setuid) {
|
||
if (uid_is_valid(uid)) {
|
||
r = enforce_user(context, uid, capability_ambient_set);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, r, "Failed to change UID to " UID_FMT ": %m", uid);
|
||
}
|
||
|
||
if (keep_seccomp_privileges) {
|
||
if (!FLAGS_SET(capability_ambient_set, (UINT64_C(1) << CAP_SETUID))) {
|
||
r = drop_capability(CAP_SETUID);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, r, "Failed to drop CAP_SETUID: %m");
|
||
}
|
||
}
|
||
|
||
r = keep_capability(CAP_SYS_ADMIN);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, r, "Failed to keep CAP_SYS_ADMIN: %m");
|
||
}
|
||
|
||
r = keep_capability(CAP_SETPCAP);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, r, "Failed to keep CAP_SETPCAP: %m");
|
||
}
|
||
}
|
||
|
||
if (capability_ambient_set != 0) {
|
||
|
||
/* Raise the ambient capabilities after user change. */
|
||
r = capability_ambient_set_apply(capability_ambient_set, /* also_inherit= */ false);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_CAPABILITIES;
|
||
return log_exec_error_errno(context, params, r, "Failed to apply ambient capabilities (after UID change): %m");
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Apply working directory here, because the working directory might be on NFS and only the user
|
||
* running this service might have the correct privilege to change to the working directory. Also, it
|
||
* is absolutely 💣 crucial 💣 we applied all mount namespacing rearrangements before this, so that
|
||
* the cwd cannot be used to pin directories outside of the sandbox. */
|
||
r = apply_working_directory(context, params, runtime, home);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_CHDIR;
|
||
return log_exec_error_errno(context, params, r, "Changing to the requested working directory failed: %m");
|
||
}
|
||
|
||
if (needs_sandboxing) {
|
||
/* Apply other MAC contexts late, but before seccomp syscall filtering, as those should really be last to
|
||
* influence our own codepaths as little as possible. Moreover, applying MAC contexts usually requires
|
||
* syscalls that are subject to seccomp filtering, hence should probably be applied before the syscalls
|
||
* are restricted. */
|
||
|
||
#if HAVE_SELINUX
|
||
if (use_selinux) {
|
||
char *exec_context = mac_selinux_context_net ?: context->selinux_context;
|
||
|
||
if (exec_context) {
|
||
r = setexeccon(exec_context);
|
||
if (r < 0) {
|
||
if (!context->selinux_context_ignore) {
|
||
*exit_status = EXIT_SELINUX_CONTEXT;
|
||
return log_exec_error_errno(context, params, r, "Failed to change SELinux context to %s: %m", exec_context);
|
||
}
|
||
log_exec_debug_errno(context,
|
||
params,
|
||
r,
|
||
"Failed to change SELinux context to %s, ignoring: %m",
|
||
exec_context);
|
||
}
|
||
}
|
||
}
|
||
#endif
|
||
|
||
#if HAVE_APPARMOR
|
||
if (use_apparmor && context->apparmor_profile) {
|
||
r = aa_change_onexec(context->apparmor_profile);
|
||
if (r < 0 && !context->apparmor_profile_ignore) {
|
||
*exit_status = EXIT_APPARMOR_PROFILE;
|
||
return log_exec_error_errno(context,
|
||
params,
|
||
errno,
|
||
"Failed to prepare AppArmor profile change to %s: %m",
|
||
context->apparmor_profile);
|
||
}
|
||
}
|
||
#endif
|
||
|
||
/* PR_GET_SECUREBITS is not privileged, while PR_SET_SECUREBITS is. So to suppress potential
|
||
* EPERMs we'll try not to call PR_SET_SECUREBITS unless necessary. Setting securebits
|
||
* requires CAP_SETPCAP. */
|
||
if (prctl(PR_GET_SECUREBITS) != secure_bits) {
|
||
/* CAP_SETPCAP is required to set securebits. This capability is raised into the
|
||
* effective set here.
|
||
*
|
||
* The effective set is overwritten during execve() with the following values:
|
||
*
|
||
* - ambient set (for non-root processes)
|
||
*
|
||
* - (inheritable | bounding) set for root processes)
|
||
*
|
||
* Hence there is no security impact to raise it in the effective set before execve
|
||
*/
|
||
r = capability_gain_cap_setpcap(/* return_caps= */ NULL);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_CAPABILITIES;
|
||
return log_exec_error_errno(context, params, r, "Failed to gain CAP_SETPCAP for setting secure bits");
|
||
}
|
||
if (prctl(PR_SET_SECUREBITS, secure_bits) < 0) {
|
||
*exit_status = EXIT_SECUREBITS;
|
||
return log_exec_error_errno(context, params, errno, "Failed to set process secure bits: %m");
|
||
}
|
||
}
|
||
|
||
if (context_has_no_new_privileges(context))
|
||
if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) < 0) {
|
||
*exit_status = EXIT_NO_NEW_PRIVILEGES;
|
||
return log_exec_error_errno(context, params, errno, "Failed to disable new privileges: %m");
|
||
}
|
||
|
||
#if HAVE_SECCOMP
|
||
r = apply_address_families(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_ADDRESS_FAMILIES;
|
||
return log_exec_error_errno(context, params, r, "Failed to restrict address families: %m");
|
||
}
|
||
|
||
r = apply_memory_deny_write_execute(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_SECCOMP;
|
||
return log_exec_error_errno(context, params, r, "Failed to disable writing to executable memory: %m");
|
||
}
|
||
|
||
r = apply_restrict_realtime(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_SECCOMP;
|
||
return log_exec_error_errno(context, params, r, "Failed to apply realtime restrictions: %m");
|
||
}
|
||
|
||
r = apply_restrict_suid_sgid(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_SECCOMP;
|
||
return log_exec_error_errno(context, params, r, "Failed to apply SUID/SGID restrictions: %m");
|
||
}
|
||
|
||
r = apply_restrict_namespaces(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_SECCOMP;
|
||
return log_exec_error_errno(context, params, r, "Failed to apply namespace restrictions: %m");
|
||
}
|
||
|
||
r = apply_protect_sysctl(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_SECCOMP;
|
||
return log_exec_error_errno(context, params, r, "Failed to apply sysctl restrictions: %m");
|
||
}
|
||
|
||
r = apply_protect_kernel_modules(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_SECCOMP;
|
||
return log_exec_error_errno(context, params, r, "Failed to apply module loading restrictions: %m");
|
||
}
|
||
|
||
r = apply_protect_kernel_logs(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_SECCOMP;
|
||
return log_exec_error_errno(context, params, r, "Failed to apply kernel log restrictions: %m");
|
||
}
|
||
|
||
r = apply_protect_clock(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_SECCOMP;
|
||
return log_exec_error_errno(context, params, r, "Failed to apply clock restrictions: %m");
|
||
}
|
||
|
||
r = apply_private_devices(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_SECCOMP;
|
||
return log_exec_error_errno(context, params, r, "Failed to set up private devices: %m");
|
||
}
|
||
|
||
r = apply_syscall_archs(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_SECCOMP;
|
||
return log_exec_error_errno(context, params, r, "Failed to apply syscall architecture restrictions: %m");
|
||
}
|
||
|
||
r = apply_lock_personality(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_SECCOMP;
|
||
return log_exec_error_errno(context, params, r, "Failed to lock personalities: %m");
|
||
}
|
||
|
||
r = apply_syscall_log(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_SECCOMP;
|
||
return log_exec_error_errno(context, params, r, "Failed to apply system call log filters: %m");
|
||
}
|
||
#endif
|
||
|
||
#if HAVE_LIBBPF
|
||
r = apply_restrict_filesystems(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_BPF;
|
||
return log_exec_error_errno(context, params, r, "Failed to restrict filesystems: %m");
|
||
}
|
||
#endif
|
||
|
||
#if HAVE_SECCOMP
|
||
/* This really should remain as close to the execve() as possible, to make sure our own code is affected
|
||
* by the filter as little as possible. */
|
||
r = apply_syscall_filter(context, params);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_SECCOMP;
|
||
return log_exec_error_errno(context, params, r, "Failed to apply system call filters: %m");
|
||
}
|
||
|
||
if (keep_seccomp_privileges) {
|
||
/* Restore the capability bounding set with what's expected from the service + the
|
||
* ambient capabilities hack */
|
||
if (!cap_test_all(saved_bset)) {
|
||
r = capability_bounding_set_drop(saved_bset, /* right_now= */ false);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_CAPABILITIES;
|
||
return log_exec_error_errno(context, params, r, "Failed to drop bset capabilities: %m");
|
||
}
|
||
}
|
||
|
||
/* Only drop CAP_SYS_ADMIN if it's not in the bounding set, otherwise we'll break
|
||
* applications that use it. */
|
||
if (!FLAGS_SET(saved_bset, (UINT64_C(1) << CAP_SYS_ADMIN))) {
|
||
r = drop_capability(CAP_SYS_ADMIN);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, r, "Failed to drop CAP_SYS_ADMIN: %m");
|
||
}
|
||
}
|
||
|
||
/* Only drop CAP_SETPCAP if it's not in the bounding set, otherwise we'll break
|
||
* applications that use it. */
|
||
if (!FLAGS_SET(saved_bset, (UINT64_C(1) << CAP_SETPCAP))) {
|
||
r = drop_capability(CAP_SETPCAP);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, r, "Failed to drop CAP_SETPCAP: %m");
|
||
}
|
||
}
|
||
|
||
if (prctl(PR_SET_KEEPCAPS, 0) < 0) {
|
||
*exit_status = EXIT_USER;
|
||
return log_exec_error_errno(context, params, errno, "Failed to drop keep capabilities flag: %m");
|
||
}
|
||
}
|
||
#endif
|
||
|
||
}
|
||
|
||
if (!strv_isempty(context->unset_environment)) {
|
||
char **ee = NULL;
|
||
|
||
ee = strv_env_delete(accum_env, 1, context->unset_environment);
|
||
if (!ee) {
|
||
*exit_status = EXIT_MEMORY;
|
||
return log_oom();
|
||
}
|
||
|
||
strv_free_and_replace(accum_env, ee);
|
||
}
|
||
|
||
if (!FLAGS_SET(command->flags, EXEC_COMMAND_NO_ENV_EXPAND)) {
|
||
_cleanup_strv_free_ char **unset_variables = NULL, **bad_variables = NULL;
|
||
|
||
r = replace_env_argv(command->argv, accum_env, &replaced_argv, &unset_variables, &bad_variables);
|
||
if (r < 0) {
|
||
*exit_status = EXIT_MEMORY;
|
||
return log_exec_error_errno(context,
|
||
params,
|
||
r,
|
||
"Failed to replace environment variables: %m");
|
||
}
|
||
final_argv = replaced_argv;
|
||
|
||
if (!strv_isempty(unset_variables)) {
|
||
_cleanup_free_ char *ju = strv_join(unset_variables, ", ");
|
||
log_exec_warning(context,
|
||
params,
|
||
"Referenced but unset environment variable evaluates to an empty string: %s",
|
||
strna(ju));
|
||
}
|
||
|
||
if (!strv_isempty(bad_variables)) {
|
||
_cleanup_free_ char *jb = strv_join(bad_variables, ", ");
|
||
log_exec_warning(context,
|
||
params,
|
||
"Invalid environment variable name evaluates to an empty string: %s",
|
||
strna(jb));
|
||
}
|
||
} else
|
||
final_argv = command->argv;
|
||
|
||
log_command_line(context, params, "Executing", executable, final_argv);
|
||
|
||
/* We have finished with all our initializations. Let's now let the manager know that. From this
|
||
* point on, if the manager sees POLLHUP on the exec_fd, then execve() was successful. */
|
||
|
||
r = exec_fd_mark_hot(context, params, /* hot= */ true, exit_status);
|
||
if (r < 0)
|
||
return r;
|
||
|
||
/* As last thing before the execve(), let's send the handoff timestamp */
|
||
r = send_handoff_timestamp(context, params, exit_status);
|
||
if (r < 0) {
|
||
/* If this handoff timestamp failed, let's undo the marking as hot */
|
||
(void) exec_fd_mark_hot(context, params, /* hot= */ false, /* reterr_exit_status= */ NULL);
|
||
return r;
|
||
}
|
||
|
||
/* NB: we leave executable_fd, exec_fd, handoff_timestamp_fd open here. This is safe, because they
|
||
* have O_CLOEXEC set, and the execve() below will thus automatically close them. In fact, for
|
||
* exec_fd this is pretty much the whole raison d'etre. */
|
||
|
||
r = fexecve_or_execve(executable_fd, executable, final_argv, accum_env);
|
||
|
||
/* The execve() failed, let's undo the marking as hot */
|
||
(void) exec_fd_mark_hot(context, params, /* hot= */ false, /* reterr_exit_status= */ NULL);
|
||
|
||
*exit_status = EXIT_EXEC;
|
||
return log_exec_error_errno(context, params, r, "Failed to execute %s: %m", executable);
|
||
}
|