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Fix old chain deletion

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This commit is contained in:
Matt Corallo 2014-05-14 03:02:47 -04:00
parent 605863ffa3
commit 08093a206d
2 changed files with 26 additions and 6 deletions
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25
js/crypto.js
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@ -279,6 +279,25 @@ window.crypto = (function() {
return new Promise(function(resolve) { resolve() });
}
var removeOldChains = function(session) {
// Sending ratchets are always removed when we step because we never need them again
// Receiving ratchets are either removed if we step with all keys used up to previousCounter
// and are otherwise added to the oldRatchetList, which we parse here and remove ratchets
// older than a week (we assume the message was lost and move on with our lives at that point)
var newList = [];
for (var i = 0; i < session.oldRatchetList.length; i++) {
var entry = session.oldRatchetList[i];
var ratchet = getString(entry.ephemeralKey);
console.log("Checking old chain with added time " + (entry.added/1000));
if (!objectContainsKeys(session[ratchet].messageKeys) || entry.added < new Date().getTime() - 1000*60*60*24*7) {
delete session[ratchet];
console.log("...deleted");
} else
newList[newList.length] = entry;
}
session.oldRatchetList = newList;
}
var maybeStepRatchet = function(session, remoteKey, previousCounter) {
if (session[getString(remoteKey)] !== undefined)
return new Promise(function(resolve) { resolve() });
@ -291,7 +310,7 @@ window.crypto = (function() {
var previousRatchet = getString(ratchet.ephemeralKeyPair.pubKey);
if (session[previousRatchet] !== undefined) {
ratchet.previousCounter = session[previousRatchet].chainKey.counter;
delete session[getString(ratchet.ephemeralKeyPair.pubKey)];
delete session[previousRatchet];
} else
// TODO: This is just an idiosyncrasy upstream, which we match for testing
// it should be changed upstream to something more reasonable.
@ -342,9 +361,9 @@ window.crypto = (function() {
return verifyMACWithVersionByte(toArrayBuffer(messageProto), keys[1], mac, (2 << 4) | 2).then(function() {
var counter = intToArrayBuffer(message.counter);
return window.crypto.subtle.decrypt({name: "AES-CTR", counter: counter}, keys[0], toArrayBuffer(message.ciphertext))
.then(function(plaintext) {
.then(function(plaintext) {
//TODO: removeOldChains(session);
removeOldChains(session);
delete session['pendingPreKey'];
crypto_storage.saveSession(encodedNumber, session);