TLS: Parse ServerHello extensions

This prints the received ServerHello extensions into the debug log and
allows handshake to continue even if such extensions are included.

Signed-off-by: Jouni Malinen <j@w1.fi>

diff --git a/src/tls/tlsv1_client_read.c b/src/tls/tlsv1_client_read.c
index 40c6a46ff23e9ae54257a792ff6efffbdf48d1b1..04419f788cb57f0af9e75ad1fe6b42c22e832556 100644 (file)
--- a/src/tls/tlsv1_client_read.c
+++ b/src/tls/tlsv1_client_read.c
@@ -1,6 +1,6 @@
 /*
  * TLSv1 client - read handshake message
- * Copyright (c) 2006-2014, Jouni Malinen <j@w1.fi>
+ * Copyright (c) 2006-2015, Jouni Malinen <j@w1.fi>
  *
  * This software may be distributed under the terms of the BSD license.
  * See README for more details.
@@ -38,6 +38,43 @@ static int tls_version_disabled(struct tlsv1_client *conn, u16 ver)
 }
 
 
+static int tls_process_server_hello_extensions(struct tlsv1_client *conn,
+                                              const u8 *pos, size_t len)
+{
+       const u8 *end = pos + len;
+
+       wpa_hexdump(MSG_MSGDUMP, "TLSv1: ServerHello extensions",
+                   pos, len);
+       while (pos < end) {
+               u16 ext, elen;
+
+               if (end - pos < 4) {
+                       wpa_printf(MSG_INFO, "TLSv1: Truncated ServerHello extension header");
+                       return -1;
+               }
+
+               ext = WPA_GET_BE16(pos);
+               pos += 2;
+               elen = WPA_GET_BE16(pos);
+               pos += 2;
+
+               if (elen > end - pos) {
+                       wpa_printf(MSG_INFO, "TLSv1: Truncated ServerHello extension");
+                       return -1;
+               }
+
+               wpa_printf(MSG_DEBUG, "TLSv1: ServerHello ExtensionType %u",
+                          ext);
+               wpa_hexdump(MSG_DEBUG, "TLSv1: ServerHello extension data",
+                           pos, elen);
+
+               pos += elen;
+       }
+
+       return 0;
+}
+
+
 static int tls_process_server_hello(struct tlsv1_client *conn, u8 ct,
                                    const u8 *in_data, size_t *in_len)
 {
@@ -177,8 +214,24 @@ static int tls_process_server_hello(struct tlsv1_client *conn, u8 ct,
        }
        pos++;
 
+       if (end - pos >= 2) {
+               u16 ext_len;
+
+               ext_len = WPA_GET_BE16(pos);
+               pos += 2;
+               if (end - pos < ext_len) {
+                       wpa_printf(MSG_INFO,
+                                  "TLSv1: Invalid ServerHello extension length: %u (left: %u)",
+                                  ext_len, (unsigned int) (end - pos));
+                       goto decode_error;
+               }
+
+               if (tls_process_server_hello_extensions(conn, pos, ext_len))
+                       goto decode_error;
+               pos += ext_len;
+       }
+
        if (end != pos) {
-               /* TODO: ServerHello extensions */
                wpa_hexdump(MSG_DEBUG, "TLSv1: Unexpected extra data in the "
                            "end of ServerHello", pos, end - pos);
                goto decode_error;