Support for directional trust

Pass in a direction to isTrusted, based on constants defined by the storage
implementation. These values allow the trust store to determine whether a given
key is trusted, given the directional context.

Author: liliakai

dist/libsignal-protocol.js

@@ -35813,7 +35813,7 @@ SessionBuilder.prototype = {
   processPreKey: function(device) {
     return Internal.SessionLock.queueJobForNumber(this.remoteAddress.toString(), function() {
       return this.storage.isTrustedIdentity(
-          this.remoteAddress.getName(), device.identityKey
+          this.remoteAddress.getName(), device.identityKey, this.storage.Direction.SENDING
       ).then(function(trusted) {
         if (!trusted) {
           throw new Error('Identity key changed');
@@ -35866,7 +35866,7 @@ SessionBuilder.prototype = {
   processV3: function(record, message) {
     var preKeyPair, signedPreKeyPair, session;
     return this.storage.isTrustedIdentity(
-        this.remoteAddress.getName(), message.identityKey.toArrayBuffer()
+        this.remoteAddress.getName(), message.identityKey.toArrayBuffer(), this.storage.Direction.RECEIVING
     ).then(function(trusted) {
         if (!trusted) {
             var e = new Error('Unknown identity key');

src/SessionBuilder.js

@@ -7,7 +7,7 @@ SessionBuilder.prototype = {
   processPreKey: function(device) {
     return Internal.SessionLock.queueJobForNumber(this.remoteAddress.toString(), function() {
       return this.storage.isTrustedIdentity(
-          this.remoteAddress.getName(), device.identityKey
+          this.remoteAddress.getName(), device.identityKey, this.storage.Direction.SENDING
       ).then(function(trusted) {
         if (!trusted) {
           throw new Error('Identity key changed');
@@ -60,7 +60,7 @@ SessionBuilder.prototype = {
   processV3: function(record, message) {
     var preKeyPair, signedPreKeyPair, session;
     return this.storage.isTrustedIdentity(
-        this.remoteAddress.getName(), message.identityKey.toArrayBuffer()
+        this.remoteAddress.getName(), message.identityKey.toArrayBuffer(), this.storage.Direction.RECEIVING
     ).then(function(trusted) {
         if (!trusted) {
             var e = new Error('Unknown identity key');

test/InMemorySignalProtocolStore.js

@@ -1,8 +1,13 @@
-function SignalProtocolStore() {
+  function SignalProtocolStore() {
   this.store = {};
 }
 
 SignalProtocolStore.prototype = {
+  Direction: {
+    SENDING: 1,
+    RECEIVING: 2,
+  },
+
   getIdentityKeyPair: function() {
     return Promise.resolve(this.get('identityKey'));
   },
@@ -29,7 +34,7 @@ SignalProtocolStore.prototype = {
     delete this.store[key];
   },
 
-  isTrustedIdentity: function(identifier, identityKey) {
+  isTrustedIdentity: function(identifier, identityKey, direction) {
     if (identifier === null || identifier === undefined) {
       throw new Error("tried to check identity key for undefined/null key");
     }