GramJS: Add more security checks (#3419)

src/global/helpers/users.ts

@@ -100,7 +100,7 @@ export function getUserStatus(
       if (!wasOnline) return lang('LastSeen.Offline');
 
       const serverTimeOffset = getServerTimeOffset();
-      const now = new Date(new Date().getTime() + serverTimeOffset * 1000);
+      const now = new Date(Date.now() + serverTimeOffset * 1000);
       const wasOnlineDate = new Date(wasOnline * 1000);
 
       if (wasOnlineDate >= now) {

src/lib/gramjs/client/TelegramClient.js

@@ -291,7 +291,7 @@ class TelegramClient {
             // for Telegram to keep delivering updates, otherwise they will
             // just stop even if we're connected. Do so every 30 minutes.
 
-            if (new Date().getTime() - this._lastRequest > 30 * 60 * 1000) {
+            if (Date.now() - this._lastRequest > 30 * 60 * 1000) {
                 try {
                     await this.pingCallback();
                 } catch (e) {
@@ -877,7 +877,7 @@ class TelegramClient {
         }
 
         const sender = dcId === undefined ? this._sender : await this.getSender(dcId);
-        this._lastRequest = new Date().getTime();
+        this._lastRequest = Date.now();
 
         const state = new RequestState(request, abortSignal);
 

src/lib/gramjs/network/Authenticator.ts

@@ -156,11 +156,15 @@ export async function doAuthentication(sender: MTProtoPlainSender, log: any) {
     const ige = new IGE(key, iv);
     const plainTextAnswer = ige.decryptIge(serverDhParams.encryptedAnswer);
     const reader = new BinaryReader(plainTextAnswer);
-    reader.read(20); // hash sum
+    const hash = reader.read(20); // hash sum
     const serverDhInner = reader.tgReadObject();
     if (!(serverDhInner instanceof Api.ServerDHInnerData)) {
         throw new Error(`Step 3 answer was ${serverDhInner}`);
     }
+    const sha1Answer = await Helpers.sha1(serverDhInner.getBytes());
+    if (!(hash.equals(sha1Answer))) {
+        throw new SecurityError('Step 3 Invalid hash answer');
+    }
 
     if (serverDhInner.nonce.neq(resPQ.nonce)) {
         throw new SecurityError('Step 3 Invalid nonce in encrypted answer');
@@ -185,7 +189,7 @@ export async function doAuthentication(sender: MTProtoPlainSender, log: any) {
         false,
     );
     const ga = Helpers.readBigIntFromBuffer(serverDhInner.gA, false, false);
-    const timeOffset = serverDhInner.serverTime - Math.floor(new Date().getTime() / 1000);
+    const timeOffset = serverDhInner.serverTime - Math.floor(Date.now() / 1000);
     const b = Helpers.readBigIntFromBuffer(
         Helpers.generateRandomBytes(256),
         false,

src/lib/gramjs/network/MTProtoState.js

@@ -284,6 +284,16 @@ class MTProtoState {
             // reader isn't used for anything else after this, it's unnecessary.
             const obj = reader.tgReadObject();
 
+            // We only check for objects that telegram has returned to us (Updates) not ones we send.
+            if (obj?.constructor.name.startsWith('Update')) {
+                const now = Math.floor(Date.now() / 1000);
+                const msgLocalTime = this.getMsgIdTimeLocal(remoteMsgId);
+
+                if (msgLocalTime && ((msgLocalTime - now) > 30 || (now - msgLocalTime) > 300)) {
+                    // 30 sec in the future or 300 sec in the past
+                    throw new SecurityError('The message time is incorrect.');
+                }
+            }
             return new TLMessage(remoteMsgId, remoteSequence, obj);
         }
     }
@@ -294,7 +304,7 @@ class MTProtoState {
      * @private
      */
     _getNewMsgId() {
-        const now = new Date().getTime() / 1000 + this.timeOffset;
+        const now = Date.now() / 1000 + this.timeOffset;
         const nanoseconds = Math.floor((now - Math.floor(now)) * 1e9);
         let newMsgId = (BigInt(Math.floor(now))
             .shiftLeft(BigInt(32))).or(BigInt(nanoseconds)
@@ -306,6 +316,17 @@ class MTProtoState {
         return newMsgId;
     }
 
+    /**
+     * Returns the understood time by the message id (server time + local offset)
+     */
+    getMsgIdTimeLocal(msgId) {
+        if (this._lastMsgId.eq(0)) {
+            // this means it's the first message sent/received so don't check yet
+            return false;
+        }
+        return msgId.shiftRight(BigInt(32)).toJSNumber() - this.timeOffset;
+    }
+
     /**
      * Updates the time offset to the correct
      * one given a known valid message ID.
@@ -314,7 +335,7 @@ class MTProtoState {
     updateTimeOffset(correctMsgId) {
         const bad = this._getNewMsgId();
         const old = this.timeOffset;
-        const now = Math.floor(new Date().getTime() / 1000);
+        const now = Math.floor(Date.now() / 1000);
         const correct = correctMsgId.shiftRight(BigInt(32));
         this.timeOffset = correct - now;
 

src/lib/gramjs/tl/MTProtoRequest.js

@@ -17,7 +17,7 @@ class MTProtoRequest {
 
     // these should not be overrode
     onSendSuccess() {
-        this.sendTime = new Date().getTime();
+        this.sendTime = Date.now();
         this.sent = true;
     }
 
@@ -26,7 +26,7 @@ class MTProtoRequest {
     }
 
     needResend() {
-        return this.dirty || (this.confirmed && !this.confirmReceived && new Date().getTime() - this.sendTime > 3000);
+        return this.dirty || (this.confirmed && !this.confirmReceived && Date.now() - this.sendTime > 3000);
     }
 
     // These should be overrode