Skip to content

Commit

Permalink
Merge pull request #809 from jryans/key-backup-version-change
Browse files Browse the repository at this point in the history 
Emit for key backup failures
  • Loading branch information
@dbkr
dbkr committed Dec 18, 2018
2 parents 3c1e9ba + 2b734b8 commit c48a6c0
Show file tree
Hide file tree
Showing 2 changed files with 102 additions and 80 deletions.
1 change: 1 addition & 0 deletions src/client.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -447,6 +447,7 @@ MatrixClient.prototype.initCrypto = async function() {
);

this.reEmitter.reEmit(crypto, [
"crypto.keyBackupFailed",
"crypto.roomKeyRequest",
"crypto.roomKeyRequestCancellation",
"crypto.warning",
Expand Down
181 changes: 101 additions & 80 deletions src/crypto/index.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,7 @@ export function isCryptoAvailable() {
}

const MIN_FORCE_SESSION_INTERVAL_MS = 60 * 60 * 1000;
const KEY_BACKUP_KEYS_PER_REQUEST = 200;

/**
* Cryptography bits
Expand Down Expand Up @@ -986,94 +987,109 @@ Crypto.prototype.importRoomKeys = function(keys) {
);
};

Crypto.prototype._maybeSendKeyBackup = async function(delay, retry) {
if (retry === undefined) retry = true;
/**
* Schedules sending all keys waiting to be sent to the backup, if not already
* scheduled. Retries if necessary.
*/
Crypto.prototype._scheduleKeyBackupSend = async function() {
if (this._sendingBackups) return;

if (!this._sendingBackups) {
this._sendingBackups = true;
try {
if (delay === undefined) {
// by default, wait between 0 and 10 seconds, to avoid backup
// requests from different clients hitting the server all at
// the same time when a new key is sent
delay = Math.random() * 10000;
try {
// wait between 0 and 10 seconds, to avoid backup
// requests from different clients hitting the server all at
// the same time when a new key is sent
const delay = Math.random() * 10000;
await Promise.delay(delay);
let numFailures = 0; // number of consecutive failures
while (1) {
if (!this.backupKey) {
return;
}
await Promise.delay(delay);
let numFailures = 0; // number of consecutive failures
while (1) {
if (!this.backupKey) {
try {
const numBackedUp =
await this._backupPendingKeys(KEY_BACKUP_KEYS_PER_REQUEST);
if (numBackedUp === 0) {
// no sessions left needing backup: we're done
return;
}
// FIXME: figure out what limit is reasonable
const sessions = await this._cryptoStore.getSessionsNeedingBackup(10);
if (!sessions.length) {
return;
}
const data = {};
for (const session of sessions) {
const roomId = session.sessionData.room_id;
if (data[roomId] === undefined) {
data[roomId] = {sessions: {}};
}

const sessionData = await this._olmDevice.exportInboundGroupSession(
session.senderKey, session.sessionId, session.sessionData,
);
sessionData.algorithm = olmlib.MEGOLM_ALGORITHM;
delete sessionData.session_id;
delete sessionData.room_id;
const firstKnownIndex = sessionData.first_known_index;
delete sessionData.first_known_index;
const encrypted = this.backupKey.encrypt(JSON.stringify(sessionData));

const forwardedCount =
(sessionData.forwarding_curve25519_key_chain || []).length;

const device = this._deviceList.getDeviceByIdentityKey(
olmlib.MEGOLM_ALGORITHM, session.senderKey,
);

data[roomId]['sessions'][session.sessionId] = {
first_message_index: firstKnownIndex,
forwarded_count: forwardedCount,
is_verified: !!(device && device.isVerified()),
session_data: encrypted,
};
}

try {
await this._baseApis.sendKeyBackup(
undefined, undefined, this.backupInfo.version,
{rooms: data},
);
numFailures = 0;
await this._cryptoStore.unmarkSessionsNeedingBackup(sessions);
} catch (err) {
numFailures++;
console.log("send failed", err);
if (err.httpStatus === 400
|| err.httpStatus === 403
|| err.httpStatus === 401
|| !retry) {
// retrying probably won't help much, so we should give up
// FIXME: disable backups?
numFailures = 0;
} catch (err) {
numFailures++;
console.log("Key backup request failed", err);
if (err.data) {
if (
err.data.errcode == 'M_NOT_FOUND' ||
err.data.errcode == 'M_WRONG_ROOM_KEYS_VERSION'
) {
// Backup version has changed or this backup version
// has been deleted
this.emit("crypto.keyBackupFailed", err.data.errcode);
throw err;
}
}
if (numFailures) {
// exponential backoff if we have failures
await new Promise((resolve, reject) => {
setTimeout(
resolve,
1000 * Math.pow(2, Math.min(numFailures - 1, 4)),
);
});
}
}
} finally {
this._sendingBackups = false;
if (numFailures) {
// exponential backoff if we have failures
await Promise.delay(1000 * Math.pow(2, Math.min(numFailures - 1, 4)));
}
}
} finally {
this._sendingBackups = false;
}
};

/**
* Take some e2e keys waiting to be backed up and send them
* to the backup.
*
* @param {integer} limit Maximum number of keys to back up
* @returns {integer} Number of sessions backed up
*/
Crypto.prototype._backupPendingKeys = async function(limit) {
const sessions = await this._cryptoStore.getSessionsNeedingBackup(limit);
if (!sessions.length) {
return 0;
}

const data = {};
for (const session of sessions) {
const roomId = session.sessionData.room_id;
if (data[roomId] === undefined) {
data[roomId] = {sessions: {}};
}

const sessionData = await this._olmDevice.exportInboundGroupSession(
session.senderKey, session.sessionId, session.sessionData,
);
sessionData.algorithm = olmlib.MEGOLM_ALGORITHM;
delete sessionData.session_id;
delete sessionData.room_id;
const firstKnownIndex = sessionData.first_known_index;
delete sessionData.first_known_index;
const encrypted = this.backupKey.encrypt(JSON.stringify(sessionData));

const forwardedCount =
(sessionData.forwarding_curve25519_key_chain || []).length;

const device = this._deviceList.getDeviceByIdentityKey(
olmlib.MEGOLM_ALGORITHM, session.senderKey,
);

data[roomId]['sessions'][session.sessionId] = {
first_message_index: firstKnownIndex,
forwarded_count: forwardedCount,
is_verified: !!(device && device.isVerified()),
session_data: encrypted,
};
}

await this._baseApis.sendKeyBackup(
undefined, undefined, this.backupInfo.version,
{rooms: data},
);
await this._cryptoStore.unmarkSessionsNeedingBackup(sessions);

return sessions.length;
};

Crypto.prototype.backupGroupSession = async function(
Expand All @@ -1090,7 +1106,9 @@ Crypto.prototype.backupGroupSession = async function(
sessionId: sessionId,
}]);

await this._maybeSendKeyBackup();
// don't wait for this to complete: it will delay so
// happens in the background
this._scheduleKeyBackupSend();
};

Crypto.prototype.backupAllGroupSessions = async function(version) {
Expand All @@ -1109,7 +1127,10 @@ Crypto.prototype.backupAllGroupSessions = async function(version) {
},
);

await this._maybeSendKeyBackup(0, false);
let numKeysBackedUp;
do {
numKeysBackedUp = await this._backupPendingKeys(KEY_BACKUP_KEYS_PER_REQUEST);
} while (numKeysBackedUp > 0);
};

/* eslint-disable valid-jsdoc */ //https://github.com/eslint/eslint/issues/7307
Expand Down

0 comments on commit c48a6c0

Please sign in to comment.