forked from GitHub-Mirror/riotX-android
173 lines
7.1 KiB
Kotlin
173 lines
7.1 KiB
Kotlin
/*
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* Copyright 2019 New Vector Ltd
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package im.vector.matrix.android.internal.crypto
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import im.vector.matrix.android.api.auth.data.Credentials
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import im.vector.matrix.android.internal.crypto.model.MXKey
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import im.vector.matrix.android.internal.crypto.model.rest.KeysUploadResponse
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import im.vector.matrix.android.internal.crypto.tasks.UploadKeysTask
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import im.vector.matrix.android.internal.session.SessionScope
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import im.vector.matrix.android.internal.util.JsonCanonicalizer
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import org.matrix.olm.OlmAccount
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import timber.log.Timber
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import java.util.*
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import javax.inject.Inject
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@SessionScope
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internal class OneTimeKeysUploader @Inject constructor(
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private val credentials: Credentials,
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private val olmDevice: MXOlmDevice,
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private val objectSigner: ObjectSigner,
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private val uploadKeysTask: UploadKeysTask
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) {
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// tell if there is a OTK check in progress
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private var oneTimeKeyCheckInProgress = false
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// last OTK check timestamp
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private var lastOneTimeKeyCheck: Long = 0
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private var oneTimeKeyCount: Int? = null
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private var lastPublishedOneTimeKeys: Map<String, Map<String, String>>? = null
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/**
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* Stores the current one_time_key count which will be handled later (in a call of
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* _onSyncCompleted). The count is e.g. coming from a /sync response.
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*
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* @param currentCount the new count
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*/
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fun updateOneTimeKeyCount(currentCount: Int) {
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oneTimeKeyCount = currentCount
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}
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/**
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* Check if the OTK must be uploaded.
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*/
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suspend fun maybeUploadOneTimeKeys() {
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if (oneTimeKeyCheckInProgress) {
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return
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}
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if (System.currentTimeMillis() - lastOneTimeKeyCheck < ONE_TIME_KEY_UPLOAD_PERIOD) {
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// we've done a key upload recently.
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return
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}
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lastOneTimeKeyCheck = System.currentTimeMillis()
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oneTimeKeyCheckInProgress = true
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// We then check how many keys we can store in the Account object.
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val maxOneTimeKeys = olmDevice.getMaxNumberOfOneTimeKeys()
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// Try to keep at most half that number on the server. This leaves the
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// rest of the slots free to hold keys that have been claimed from the
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// server but we haven't received a message for.
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// If we run out of slots when generating new keys then olm will
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// discard the oldest private keys first. This will eventually clean
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// out stale private keys that won't receive a message.
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val keyLimit = Math.floor(maxOneTimeKeys / 2.0).toInt()
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if (oneTimeKeyCount != null) {
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uploadOTK(oneTimeKeyCount!!, keyLimit)
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} else {
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// ask the server how many keys we have
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val uploadKeysParams = UploadKeysTask.Params(null, null, credentials.deviceId!!)
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val response = uploadKeysTask.execute(uploadKeysParams)
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// We need to keep a pool of one time public keys on the server so that
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// other devices can start conversations with us. But we can only store
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// a finite number of private keys in the olm Account object.
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// To complicate things further then can be a delay between a device
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// claiming a public one time key from the server and it sending us a
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// message. We need to keep the corresponding private key locally until
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// we receive the message.
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// But that message might never arrive leaving us stuck with duff
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// private keys clogging up our local storage.
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// So we need some kind of engineering compromise to balance all of
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// these factors.
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// TODO Why we do not set oneTimeKeyCount here?
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// TODO This is not needed anymore, see https://github.com/matrix-org/matrix-js-sdk/pull/493 (TODO on iOS also)
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val keyCount = response.oneTimeKeyCountsForAlgorithm(MXKey.KEY_SIGNED_CURVE_25519_TYPE)
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uploadOTK(keyCount, keyLimit)
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}
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Timber.v("## uploadKeys() : success")
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oneTimeKeyCount = null
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oneTimeKeyCheckInProgress = false
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}
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/**
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* Upload some the OTKs.
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*
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* @param keyCount the key count
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* @param keyLimit the limit
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*/
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private suspend fun uploadOTK(keyCount: Int, keyLimit: Int) {
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if (keyLimit <= keyCount) {
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// If we don't need to generate any more keys then we are done.
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return
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}
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val keysThisLoop = Math.min(keyLimit - keyCount, ONE_TIME_KEY_GENERATION_MAX_NUMBER)
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olmDevice.generateOneTimeKeys(keysThisLoop)
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val response = uploadOneTimeKeys()
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if (response.hasOneTimeKeyCountsForAlgorithm(MXKey.KEY_SIGNED_CURVE_25519_TYPE)) {
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uploadOTK(response.oneTimeKeyCountsForAlgorithm(MXKey.KEY_SIGNED_CURVE_25519_TYPE), keyLimit)
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} else {
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Timber.e("## uploadLoop() : response for uploading keys does not contain one_time_key_counts.signed_curve25519")
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throw Exception("response for uploading keys does not contain one_time_key_counts.signed_curve25519")
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}
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}
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/**
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* Upload my user's one time keys.
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*/
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private suspend fun uploadOneTimeKeys(): KeysUploadResponse {
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val oneTimeKeys = olmDevice.getOneTimeKeys()
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val oneTimeJson = HashMap<String, Any>()
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val curve25519Map = oneTimeKeys?.get(OlmAccount.JSON_KEY_ONE_TIME_KEY)
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if (null != curve25519Map) {
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for (key_id in curve25519Map.keys) {
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val k = HashMap<String, Any>()
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k["key"] = curve25519Map.getValue(key_id)
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// the key is also signed
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val canonicalJson = JsonCanonicalizer.getCanonicalJson(Map::class.java, k)
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k["signatures"] = objectSigner.signObject(canonicalJson)
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oneTimeJson["signed_curve25519:$key_id"] = k
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}
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}
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// For now, we set the device id explicitly, as we may not be using the
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// same one as used in login.
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val uploadParams = UploadKeysTask.Params(null, oneTimeJson, credentials.deviceId!!)
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val response = uploadKeysTask.execute(uploadParams)
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lastPublishedOneTimeKeys = oneTimeKeys
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olmDevice.markKeysAsPublished()
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return response
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}
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companion object {
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// max number of keys to upload at once
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// Creating keys can be an expensive operation so we limit the
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// number we generate in one go to avoid blocking the application
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// for too long.
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private const val ONE_TIME_KEY_GENERATION_MAX_NUMBER = 5
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// frequency with which to check & upload one-time keys
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private const val ONE_TIME_KEY_UPLOAD_PERIOD = (60 * 1000).toLong() // one minute
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}
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} |