6543/BayernMessenger
1
0
Fork 0
forked from GitHub-Mirror/riotX-android
Code Issues 4 Pull Requests Releases Wiki Activity

Decrypt Attachment - WIP

Browse Source
This commit is contained in:
Benoit Marty
2019-06-24 22:33:30 +02:00
parent 707a4712fc
commit b54ca5a8a0
12 changed files with 302 additions and 48 deletions
Download Patch File Download Diff File Expand all files Collapse all files

46
matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/crypto/attachments/ElementToDecrypt.kt Normal file
View File

@ -0,0 +1,46 @@
/*
* Copyright 2016 OpenMarket Ltd
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package im.vector.matrix.android.internal.crypto.attachments
import android.os.Parcelable
import im.vector.matrix.android.internal.crypto.model.rest.EncryptedFileInfo
import kotlinx.android.parcel.Parcelize
fun EncryptedFileInfo.toElementToDecrypt(): ElementToDecrypt? {
// Check the validity of some fields
if (isValid()) {
return ElementToDecrypt(
iv = this.iv!!,
k = this.key!!.k!!,
sha256 = this.hashes!!["sha256"] ?: error("")
)
}
return null
}
/**
* Represent data to decode an attachment
*/
@Parcelize
data class ElementToDecrypt(
val iv: String,
val k: String,
val sha256: String
) : Parcelable

45
matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/crypto/MXEncryptedAttachments.kt → matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/crypto/attachments/MXEncryptedAttachments.kt
View File

@ -14,7 +14,7 @@
* limitations under the License.
*/
package im.vector.matrix.android.internal.crypto
package im.vector.matrix.android.internal.crypto.attachments
import android.text.TextUtils
import android.util.Base64
@ -142,24 +142,27 @@ object MXEncryptedAttachments {
* @return the decrypted attachment stream
*/
fun decryptAttachment(attachmentStream: InputStream?, encryptedFileInfo: EncryptedFileInfo?): InputStream? {
if (encryptedFileInfo?.isValid() != true) {
Timber.e("## decryptAttachment() : some fields are not defined, or invalid key fields")
return null
}
val elementToDecrypt = encryptedFileInfo.toElementToDecrypt()
return decryptAttachment(attachmentStream, elementToDecrypt)
}
/**
* Decrypt an attachment
*
* @param attachmentStream the attachment stream
* @param elementToDecrypt the elementToDecrypt info
* @return the decrypted attachment stream
*/
fun decryptAttachment(attachmentStream: InputStream?, elementToDecrypt: ElementToDecrypt?): InputStream? {
// sanity checks
if (null == attachmentStream || null == encryptedFileInfo) {
Timber.e("## decryptAttachment() : null parameters")
return null
}
if (TextUtils.isEmpty(encryptedFileInfo.iv)
|| null == encryptedFileInfo.key
|| null == encryptedFileInfo.hashes
|| !encryptedFileInfo.hashes.containsKey("sha256")) {
Timber.e("## decryptAttachment() : some fields are not defined")
return null
}
if (!TextUtils.equals(encryptedFileInfo.key!!.alg, "A256CTR")
|| !TextUtils.equals(encryptedFileInfo.key!!.kty, "oct")
|| TextUtils.isEmpty(encryptedFileInfo.key!!.k)) {
Timber.e("## decryptAttachment() : invalid key fields")
if (null == attachmentStream || elementToDecrypt == null) {
Timber.e("## decryptAttachment() : null stream")
return null
}
@ -177,8 +180,8 @@ object MXEncryptedAttachments {
val outStream = ByteArrayOutputStream()
try {
val key = Base64.decode(base64UrlToBase64(encryptedFileInfo.key!!.k), Base64.DEFAULT)
val initVectorBytes = Base64.decode(encryptedFileInfo.iv, Base64.DEFAULT)
val key = Base64.decode(base64UrlToBase64(elementToDecrypt.k), Base64.DEFAULT)
val initVectorBytes = Base64.decode(elementToDecrypt.iv, Base64.DEFAULT)
val decryptCipher = Cipher.getInstance(CIPHER_ALGORITHM)
val secretKeySpec = SecretKeySpec(key, SECRET_KEY_SPEC_ALGORITHM)
@ -205,7 +208,7 @@ object MXEncryptedAttachments {
val currentDigestValue = base64ToUnpaddedBase64(Base64.encodeToString(messageDigest.digest(), Base64.DEFAULT))
if (!TextUtils.equals(encryptedFileInfo.hashes["sha256"], currentDigestValue)) {
if (!TextUtils.equals(elementToDecrypt.sha256, currentDigestValue)) {
Timber.e("## decryptAttachment() : Digest value mismatch")
outStream.close()
return null

35
matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/crypto/model/rest/EncryptedFileInfo.kt
View File

@ -33,7 +33,7 @@ data class EncryptedFileInfo(
* Not documented
*/
@Json(name = "mimetype")
var mimetype: String,
var mimetype: String? = null,
/**
* Required. A JSON Web Key object.
@ -45,18 +45,45 @@ data class EncryptedFileInfo(
* Required. The Initialisation Vector used by AES-CTR, encoded as unpadded base64.
*/
@Json(name = "iv")
var iv: String,
var iv: String? = null,
/**
* Required. A map from an algorithm name to a hash of the ciphertext, encoded as unpadded base64.
* Clients should support the SHA-256 hash, which uses the key "sha256".
*/
@Json(name = "hashes")
var hashes: Map<String, String>,
var hashes: Map<String, String>? = null,
/**
* Required. Version of the encrypted attachments protocol. Must be "v2".
*/
@Json(name = "v")
var v: String? = null
)
) {
/**
* Check what the spec tells us
*/
fun isValid(): Boolean {
if (url.isNullOrBlank()) {
return false
}
if (key?.isValid() != true) {
return false
}
if (iv.isNullOrBlank()) {
return false
}
if (hashes?.containsKey("sha256") != true) {
return false
}
if (v != "v2") {
return false
}
return true
}
}

37
matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/crypto/model/rest/EncryptedFileKey.kt
View File

@ -24,7 +24,7 @@ data class EncryptedFileKey(
* Required. Algorithm. Must be "A256CTR".
*/
@Json(name = "alg")
var alg: String,
var alg: String? = null,
/**
* Required. Extractable. Must be true. This is a W3C extension.
@ -36,18 +36,45 @@ data class EncryptedFileKey(
* Required. Key operations. Must at least contain "encrypt" and "decrypt".
*/
@Json(name = "key_ops")
var key_ops: List<String>,
var key_ops: List<String>? = null,
/**
* Required. Key type. Must be "oct".
*/
@Json(name = "kty")
var kty: String,
var kty: String? = null,
/**
* Required. The key, encoded as urlsafe unpadded base64.
*/
@Json(name = "k")
var k: String
)
var k: String? = null
) {
/**
* Check what the spec tells us
*/
fun isValid(): Boolean {
if (alg != "A256CTR") {
return false
}
if (ext != true) {
return false
}
if (key_ops?.contains("encrypt") != true || key_ops?.contains("decrypt") != true) {
return false
}
if (kty != "oct") {
return false
}
if (k.isNullOrBlank()) {
return false
}
return true
}
}