commit 367381fdddb68e72c408fed763b955f620abf451
author Manuel Pégourié-Gonnard <mpg@elzevir.fr> Mon Oct 20 18:40:56 2014 +0200
committer Manuel Pégourié-Gonnard <mpg@elzevir.fr> Wed Nov 05 16:00:49 2014 +0100
tree fc613d395494254365988f229390c0da225c7441
parent 178f9d6e190d0f19ee9485e059e258650b5dac98

Add negotiation of Extended Master Secret

(But not the actual thing yet.)

library/ssl_cli.c

diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 50ab05f..065f3a8 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -359,6 +359,31 @@
 }
 #endif /* POLARSSL_SSL_TRUNCATED_HMAC */
 
+#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
+static void ssl_write_extended_ms_ext( ssl_context *ssl,
+                                       unsigned char *buf, size_t *olen )
+{
+    unsigned char *p = buf;
+
+    if( ssl->extended_ms == SSL_EXTENDED_MS_DISABLED )
+    {
+        *olen = 0;
+        return;
+    }
+
+    SSL_DEBUG_MSG( 3, ( "client hello, adding extended_master_secret "
+                        "extension" ) );
+
+    *p++ = (unsigned char)( ( TLS_EXT_EXTENDED_MASTER_SECRET >> 8 ) & 0xFF );
+    *p++ = (unsigned char)( ( TLS_EXT_EXTENDED_MASTER_SECRET      ) & 0xFF );
+
+    *p++ = 0x00;
+    *p++ = 0x00;
+
+    *olen = 4;
+}
+#endif /* POLARSSL_SSL_EXTENDED_MASTER_SECRET */
+
 #if defined(POLARSSL_SSL_SESSION_TICKETS)
 static void ssl_write_session_ticket_ext( ssl_context *ssl,
                                           unsigned char *buf, size_t *olen )
@@ -662,6 +687,11 @@
     ext_len += olen;
 #endif
 
+#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
+    ssl_write_extended_ms_ext( ssl, p + 2 + ext_len, &olen );
+    ext_len += olen;
+#endif
+
 #if defined(POLARSSL_SSL_SESSION_TICKETS)
     ssl_write_session_ticket_ext( ssl, p + 2 + ext_len, &olen );
     ext_len += olen;
@@ -780,6 +810,25 @@
 }
 #endif /* POLARSSL_SSL_TRUNCATED_HMAC */
 
+#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
+static int ssl_parse_extended_ms_ext( ssl_context *ssl,
+                                         const unsigned char *buf,
+                                         size_t len )
+{
+    if( ssl->extended_ms == SSL_EXTENDED_MS_DISABLED ||
+        len != 0 )
+    {
+        return( POLARSSL_ERR_SSL_BAD_HS_SERVER_HELLO );
+    }
+
+    ((void) buf);
+
+    ssl->handshake->extended_ms = SSL_EXTENDED_MS_ENABLED;
+
+    return( 0 );
+}
+#endif /* POLARSSL_SSL_EXTENDED_MASTER_SECRET */
+
 #if defined(POLARSSL_SSL_SESSION_TICKETS)
 static int ssl_parse_session_ticket_ext( ssl_context *ssl,
                                          const unsigned char *buf,
@@ -1152,6 +1201,19 @@
             break;
 #endif /* POLARSSL_SSL_TRUNCATED_HMAC */
 
+#if defined(POLARSSL_SSL_EXTENDED_MASTER_SECRET)
+        case TLS_EXT_EXTENDED_MASTER_SECRET:
+            SSL_DEBUG_MSG( 3, ( "found extended_master_secret extension" ) );
+
+            if( ( ret = ssl_parse_extended_ms_ext( ssl,
+                            ext + 4, ext_size ) ) != 0 )
+            {
+                return( ret );
+            }
+
+            break;
+#endif /* POLARSSL_SSL_EXTENDED_MASTER_SECRET */
+
 #if defined(POLARSSL_SSL_SESSION_TICKETS)
         case TLS_EXT_SESSION_TICKET:
             SSL_DEBUG_MSG( 3, ( "found session_ticket extension" ) );