SSH2Stream: fix DSA signature adjustment

mscdex · Mar 15, 2015 · d4ecde6 · d4ecde6
1 parent f6601ba
commit d4ecde6
Showing 1 changed file with 16 additions and 2 deletions.
diff --git a/lib/ssh.js b/lib/ssh.js
@@ -3510,8 +3510,22 @@ function parsePacket(self, callback) {
           // OpenSSL
           var asnSigWriter = new Ber.Writer();
           asnSigWriter.startSequence();
-          asnSigWriter.writeBuffer(signature.slice(0, 20), Ber.Integer);
-          asnSigWriter.writeBuffer(signature.slice(20), Ber.Integer);
+          var rBuf = signature.slice(0, 20);
+          var sBuf = signature.slice(20);
+          if (rBuf[0] & 0x80) {
+            var rNew = new Buffer(21);
+            rNew[0] = 0x00;
+            rBuf.copy(rNew, 1);
+            rBuf = rNew;
+          }
+          if (sBuf[0] & 0x80) {
+            var sNew = new Buffer(21);
+            sNew[0] = 0x00;
+            sBuf.copy(sNew, 1);
+            sBuf = sNew;
+          }
+          asnSigWriter.writeBuffer(rBuf, Ber.Integer);
+          asnSigWriter.writeBuffer(sBuf, Ber.Integer);
           asnSigWriter.endSequence();
           signature = asnSigWriter.buffer;
         }