Fixed wrongly rejected RSA signatures

lib/rsa.js

 /*
  * This file is part of the Adblock Plus extension,
  * Copyright (C) 2006-2012 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 157 matching lines @@
         return digest.charCodeAt(pos++);
       }
 
       // Skip padding, see http://tools.ietf.org/html/rfc3447#section-9.2 step 5
       if (next() != 1)
         throw "Wrong padding in signature digest";
       while (next() == 255) {}
       if (digest.charCodeAt(pos - 1) != 0)
         throw "Wrong padding in signature digest";
 
-      // Rest is an ASN.1 structure, get the SHA1 hash from it
-      var sha1 = readASN1(digest.substr(pos), signatureTemplate).sha1.toString(16);
-      while (sha1.length < 40)
-        sha1 = "0" + sha1;  // Zero-pad to the right length
-      return (sha1 == SHA1(data));
+      // Rest is an ASN.1 structure, get the SHA1 hash from it and compare to
+      // the real one
+      var sha1 = readASN1(digest.substr(pos), signatureTemplate).sha1;
+      var expected = new BigInteger(SHA1(data), 16);
+      return (sha1.compareTo(expected) == 0);
     }
     catch (e)
     {
       console.log("Invalid encrypted signature: " + e);
       return false;
     }
   }
 
   // Export verifySignature function, everything else is private.
   globalObj.verifySignature = verifySignature;
 })(this);