OpenSSL: add support for the TLS padding extension.

openssl/ssl/s3_clnt.c

 /* ssl/s3_clnt.c */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
  * This package is an SSL implementation written
  * by Eric Young (eay@cryptsoft.com).
  * The implementation was written so as to conform with Netscapes SSL.
  * 
  * This library is free for commercial and non-commercial use as long as
  * the following conditions are aheared to.  The following conditions
@@ skipping 739 matching lines @@
                                 goto err;
                         }
                 /* else use the pre-loaded session */
 
                 p=s->s3->client_random;
                 Time=(unsigned long)time(NULL);                 /* Time */
                 l2n(Time,p);
                 if (RAND_pseudo_bytes(p,SSL3_RANDOM_SIZE-4) <= 0)
                         goto err;
 
-                /* Do the message type and length last */
+                /* Do the message type and length last.
+                 * Note: the code to add the padding extension in t1_lib.c
+                 * depends on the size of this prefix. */
                 d=p= &(buf[4]);
 
                 /* version indicates the negotiated version: for example from
                  * an SSLv2/v3 compatible client hello). The client_version
                  * field is the maximum version we permit and it is also
                  * used in RSA encrypted premaster secrets. Some servers can
                  * choke if we initially report a higher version then
                  * renegotiate to a lower one in the premaster secret. This
                  * didn't happen with TLS 1.0 as most servers supported it
                  * but it can with TLS 1.1 or later if the server only supports
@@ skipping 2797 matching lines @@
                                                 SSL_get_client_CA_list(s),
                                                 px509, ppkey, NULL, NULL, NULL);
                 if (i != 0)
                         return i;
                 }
 #endif
         if (s->ctx->client_cert_cb)
                 i = s->ctx->client_cert_cb(s,px509,ppkey);
         return i;
         }