matrix/matrix-js-sdk
1
0
Fork 0
mirror of https://github.com/matrix-org/matrix-js-sdk.git synced 2025-11-25 05:23:13 +03:00
Code Activity

Don't share full key history for RTC per-participant encryption (#4406)

Browse Source 
* Don't share full key history for RTC per-participant encryption

Also record stats for how many keys have been sent/received and age of those received

* Update src/matrixrtc/MatrixRTCSession.ts

Co-authored-by: Robin <robin@robin.town>

* Add comment about why we track total age of events

---------

Co-authored-by: Robin <robin@robin.town>
This commit is contained in:
Hugh Nimmo-Smith
2024-09-18 09:57:26 +01:00
committed by GitHub
parent 30058a4bdc
commit 414ac9d8cc
3 changed files with 187 additions and 30 deletions
Download Patch File Download Diff File Expand all files Collapse all files

82
src/matrixrtc/MatrixRTCSession.ts
View File

@@ -144,6 +144,31 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
// if it looks like a membership has been updated.
private lastMembershipFingerprints: Set<string> | undefined;
private currentEncryptionKeyIndex = -1;
/**
* The statistics for this session.
*/
public statistics = {
counters: {
/**
* The number of times we have sent a room event containing encryption keys.
*/
roomEventEncryptionKeysSent: 0,
/**
* The number of times we have received a room event containing encryption keys.
*/
roomEventEncryptionKeysReceived: 0,
},
totals: {
/**
* The total age (in milliseconds) of all room events containing encryption keys that we have received.
* We track the total age so that we can later calculate the average age of all keys received.
*/
roomEventEncryptionKeysReceivedTotalAge: 0,
},
};
/**
* The callId (sessionId) of the call.
*
@@ -467,10 +492,16 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
const useKeyTimeout = setTimeout(() => {
this.setNewKeyTimeouts.delete(useKeyTimeout);
logger.info(`Delayed-emitting key changed event for ${participantId} idx ${encryptionKeyIndex}`);
if (userId === this.client.getUserId() && deviceId === this.client.getDeviceId()) {
this.currentEncryptionKeyIndex = encryptionKeyIndex;
}
this.emit(MatrixRTCSessionEvent.EncryptionKeyChanged, keyBin, encryptionKeyIndex, participantId);
}, USE_KEY_DELAY);
this.setNewKeyTimeouts.add(useKeyTimeout);
} else {
if (userId === this.client.getUserId() && deviceId === this.client.getDeviceId()) {
this.currentEncryptionKeyIndex = encryptionKeyIndex;
}
this.emit(MatrixRTCSessionEvent.EncryptionKeyChanged, keyBin, encryptionKeyIndex, participantId);
}
}
@@ -479,8 +510,9 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
* Generate a new sender key and add it at the next available index
* @param delayBeforeUse - If true, wait for a short period before setting the key for the
* media encryptor to use. If false, set the key immediately.
* @returns The index of the new key
*/
private makeNewSenderKey(delayBeforeUse = false): void {
private makeNewSenderKey(delayBeforeUse = false): number {
const userId = this.client.getUserId();
const deviceId = this.client.getDeviceId();
@@ -491,6 +523,7 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
const encryptionKeyIndex = this.getNewEncryptionKeyIndex();
logger.info("Generated new key at index " + encryptionKeyIndex);
this.setEncryptionKey(userId, deviceId, encryptionKeyIndex, encryptionKey, Date.now(), delayBeforeUse);
return encryptionKeyIndex;
}
/**
@@ -517,17 +550,17 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
/**
* Re-sends the encryption keys room event
*/
private sendEncryptionKeysEvent = async (): Promise<void> => {
private sendEncryptionKeysEvent = async (indexToSend?: number): Promise<void> => {
if (this.keysEventUpdateTimeout !== undefined) {
clearTimeout(this.keysEventUpdateTimeout);
this.keysEventUpdateTimeout = undefined;
}
this.lastEncryptionKeyUpdateRequest = Date.now();
logger.info("Sending encryption keys event");
if (!this.isJoined()) return;
logger.info(`Sending encryption keys event. indexToSend=${indexToSend}`);
const userId = this.client.getUserId();
const deviceId = this.client.getDeviceId();
@@ -541,20 +574,33 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
return;
}
if (typeof indexToSend !== "number" && this.currentEncryptionKeyIndex === -1) {
logger.warn("Tried to send encryption keys event but no current key index found!");
return;
}
const keyIndexToSend = indexToSend ?? this.currentEncryptionKeyIndex;
const keyToSend = myKeys[keyIndexToSend];
try {
await this.client.sendEvent(this.room.roomId, EventType.CallEncryptionKeysPrefix, {
keys: myKeys.map((key, index) => {
return {
index,
key: encodeUnpaddedBase64(key),
};
}),
const content: EncryptionKeysEventContent = {
keys: [
{
index: keyIndexToSend,
key: encodeUnpaddedBase64(keyToSend),
},
],
device_id: deviceId,
call_id: "",
} as EncryptionKeysEventContent);
sent_ts: Date.now(),
};
this.statistics.counters.roomEventEncryptionKeysSent += 1;
await this.client.sendEvent(this.room.roomId, EventType.CallEncryptionKeysPrefix, content);
logger.debug(
`Embedded-E2EE-LOG updateEncryptionKeyEvent participantId=${userId}:${deviceId} numSent=${myKeys.length}`,
`Embedded-E2EE-LOG updateEncryptionKeyEvent participantId=${userId}:${deviceId} numKeys=${myKeys.length} currentKeyIndex=${this.currentEncryptionKeyIndex} keyIndexToSend=${keyIndexToSend}`,
this.encryptionKeys,
);
} catch (error) {
@@ -649,6 +695,10 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
return;
}
this.statistics.counters.roomEventEncryptionKeysReceived += 1;
const age = Date.now() - (typeof content.sent_ts === "number" ? content.sent_ts : event.getTs());
this.statistics.totals.roomEventEncryptionKeysReceivedTotalAge += age;
for (const key of content.keys) {
if (!key) {
logger.info("Ignoring false-y key in keys event");
@@ -674,7 +724,7 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
);
} else {
logger.debug(
`Embedded-E2EE-LOG onCallEncryption userId=${userId}:${deviceId} encryptionKeyIndex=${encryptionKeyIndex}`,
`Embedded-E2EE-LOG onCallEncryption userId=${userId}:${deviceId} encryptionKeyIndex=${encryptionKeyIndex} age=${age}ms`,
this.encryptionKeys,
);
this.setEncryptionKey(userId, deviceId, encryptionKeyIndex, encryptionKey, event.getTs());
@@ -1030,9 +1080,9 @@ export class MatrixRTCSession extends TypedEventEmitter<MatrixRTCSessionEvent, M
this.makeNewKeyTimeout = undefined;
logger.info("Making new sender key for key rotation");
this.makeNewSenderKey(true);
const newKeyIndex = this.makeNewSenderKey(true);
// send immediately: if we're about to start sending with a new key, it's
// important we get it out to others as soon as we can.
this.sendEncryptionKeysEvent();
this.sendEncryptionKeysEvent(newKeyIndex);
};
}