New tls channel id version for OpenSSL

openssl/ssl/t1_lib.c

 /* ssl/t1_lib.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 2656 matching lines @@
         unsigned temp_digest_len;
         int i;
         static const char kClientIDMagic[] = "TLS Channel ID signature";
 
         if (s->s3->handshake_buffer)
                 if (!ssl3_digest_cached_records(s))
                         return 0;
 
         EVP_DigestUpdate(md, kClientIDMagic, sizeof(kClientIDMagic));
 
+        if (s->hit)
+                {
+                static const char kResumptionMagic[] = "Resumption";
+                EVP_DigestUpdate(md, kResumptionMagic,
+                                 sizeof(kResumptionMagic));
+                if (s->session->original_handshake_hash_len == 0)
+                        return 0;
+                EVP_DigestUpdate(md, s->session->original_handshake_hash,
+                                 s->session->original_handshake_hash_len);
+                }
+
         EVP_MD_CTX_init(&ctx);
         for (i = 0; i < SSL_MAX_DIGEST; i++)
                 {
                 if (s->s3->handshake_dgst[i] == NULL)
                         continue;
                 EVP_MD_CTX_copy_ex(&ctx, s->s3->handshake_dgst[i]);
                 EVP_DigestFinal_ex(&ctx, temp_digest, &temp_digest_len);
                 EVP_DigestUpdate(md, temp_digest, temp_digest_len);
                 }
         EVP_MD_CTX_cleanup(&ctx);
 
         return 1;
         }
 #endif
+
+/* tls1_record_handshake_hashes_for_channel_id records the current handshake
+ * hashes in |s->session| so that Channel ID resumptions can sign that data. */
+int tls1_record_handshake_hashes_for_channel_id(SSL *s)
+        {
+        int digest_len;
+        /* This function should never be called for a resumed session because
+         * the handshake hashes that we wish to record are for the original,
+         * full handshake. */
+        if (s->hit)
+                return -1;
+        /* It only makes sense to call this function if Channel IDs have been
+         * negotiated. */
+        if (!s->s3->tlsext_channel_id_valid)
+                return -1;
+
+        digest_len = tls1_handshake_digest(
+                s, s->session->original_handshake_hash,
+                sizeof(s->session->original_handshake_hash));
+        if (digest_len < 0)
+                return -1;
+
+        s->session->original_handshake_hash_len = digest_len;
+
+        return 1;
+        }