Clear bytes used for block padding of SSL 3.0 records. (CVE-2011-4576)

CHANGES

@@ -523,6 +523,10 @@
 
  Changes between 1.0.0e and 1.0.0f [xx XXX xxxx]
 
+  *) Clear bytes used for block padding of SSL 3.0 records.
+     (CVE-2011-4576)
+     [Adam Langley (Google)]
+
   *) Only allow one SGC handshake restart for SSL/TLS. (CVE-2011-4619)
      [Adam Langley (Google)]
 

ssl/s3_enc.c

@@ -512,6 +512,9 @@ int ssl3_enc(SSL *s, int send)
 
 			/* we need to add 'i-1' padding bytes */
 			l+=i;
+			/* the last of these zero bytes will be overwritten
+			 * with the padding length. */
+			memset(&rec->input[rec->length], 0, i);
 			rec->length+=i;
 			rec->input[l-1]=(i-1);
 			}