Fix GNUTLS-SA-2008-1 security vulnerabilities.

See http://www.gnu.org/software/gnutls/security.html for updates.

3 files changed, 39 insertions, 10 deletions

diff --git a/lib/ext_server_name.c b/lib/ext_server_name.c
index 4e765153bb..bfcee9d367 100644
--- a/lib/ext_server_name.c
+++ b/lib/ext_server_name.c
@@ -74,10 +74,27 @@ _gnutls_server_name_recv_params (gnutls_session_t session,
 	  len = _gnutls_read_uint16 (p);
 	  p += 2;
 
-	  DECR_LENGTH_RET (data_size, len, 0);
-	  server_names++;
+	  if (len > 0)
+	    {
+	      DECR_LENGTH_RET (data_size, len, 0);
+	      server_names++;
+	      p += len;
+	    }
+	  else
+	    _gnutls_handshake_log
+	      ("HSK[%x]: Received zero size server name (under attack?)\n",
+	       session);
 
-	  p += len;
+	}
+
+      /* we cannot accept more server names.
+       */
+      if (server_names > MAX_SERVER_NAME_EXTENSIONS)
+	{
+	  _gnutls_handshake_log
+	    ("HSK[%x]: Too many server names received (under attack?)\n",
+	     session);
+	  server_names = MAX_SERVER_NAME_EXTENSIONS;
 	}
 
       session->security_parameters.extensions.server_names_size =
@@ -85,10 +102,6 @@ _gnutls_server_name_recv_params (gnutls_session_t session,
       if (server_names == 0)
 	return 0;		/* no names found */
 
-      /* we cannot accept more server names.
-       */
-      if (server_names > MAX_SERVER_NAME_EXTENSIONS)
-	server_names = MAX_SERVER_NAME_EXTENSIONS;
 
       p = data + 2;
       for (i = 0; i < server_names; i++)
diff --git a/lib/gnutls_cipher.c b/lib/gnutls_cipher.c
index e930c1de3f..f071710034 100644
--- a/lib/gnutls_cipher.c
+++ b/lib/gnutls_cipher.c
@@ -453,6 +453,14 @@ _gnutls_ciphertext2compressed (gnutls_session_t session,
       return GNUTLS_E_INTERNAL_ERROR;
     }
 
+  if (ciphertext.size < (unsigned) blocksize + hash_size)
+    {
+      _gnutls_record_log
+	("REC[%x]: Short record length %d < %d + %d (under attack?)\n",
+	 session, ciphertext.size, blocksize, hash_size);
+      gnutls_assert ();
+      return GNUTLS_E_DECRYPTION_FAILED;
+    }
 
   /* actual decryption (inplace)
    */
@@ -504,9 +512,7 @@ _gnutls_ciphertext2compressed (gnutls_session_t session,
 
       pad = ciphertext.data[ciphertext.size - 1] + 1;	/* pad */
 
-      length = ciphertext.size - hash_size - pad;
-
-      if (pad > ciphertext.size - hash_size)
+      if ((int)pad > (int)ciphertext.size - hash_size)
 	{
 	  gnutls_assert ();
 	  /* We do not fail here. We check below for the
@@ -515,6 +521,8 @@ _gnutls_ciphertext2compressed (gnutls_session_t session,
 	  pad_failed = GNUTLS_E_DECRYPTION_FAILED;
 	}
 
+      length = ciphertext.size - hash_size - pad;
+
       /* Check the pading bytes (TLS 1.x)
        */
       if (ver >= GNUTLS_TLS1 && pad_failed == 0)
diff --git a/lib/gnutls_handshake.c b/lib/gnutls_handshake.c
index 2737edff85..cec3283221 100644
--- a/lib/gnutls_handshake.c
+++ b/lib/gnutls_handshake.c
@@ -1001,6 +1001,14 @@ _gnutls_recv_handshake_header (gnutls_session_t session,
 
       *recv_type = session->internals.handshake_header_buffer.recv_type;
 
+      if (*recv_type != type)
+	{
+	  gnutls_assert ();
+	  _gnutls_handshake_log
+	    ("HSK[%x]: Handshake type mismatch (under attack?)\n", session);
+	  return GNUTLS_E_UNEXPECTED_HANDSHAKE_PACKET;
+	}
+
       return session->internals.handshake_header_buffer.packet_length;
     }