Get rid of memmove for DTLS in parse_client_hello()
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 69d3d3e..a1c2c4d 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -1275,19 +1275,41 @@
ssl->handshake->update_checksum( ssl, buf, msg_len );
/*
- * The DTLS handshake layer contains additional fields. Use them, then
- * remove them so that it looks like TLS format to the rest of the code.
+ * Handshake layer:
+ * 0 . 0 handshake type
+ * 1 . 3 handshake length
+ * 4 . 5 DTLS only: message seqence number
+ * 6 . 8 DTLS only: fragment offset
+ * 9 . 11 DTLS only: fragment length
*/
+ if( msg_len < ssl_hs_hdr_len( ssl ) )
+ {
+ SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+ return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
+ }
+
+ SSL_DEBUG_MSG( 3, ( "client hello v3, handshake type: %d", buf[0] ) );
+
+ if( buf[0] != SSL_HS_CLIENT_HELLO )
+ {
+ SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+ return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
+ }
+
+ SSL_DEBUG_MSG( 3, ( "client hello v3, handshake len.: %d",
+ ( buf[1] << 16 ) | ( buf[2] << 8 ) | buf[3] ) );
+
+ /* We don't support fragmentation of ClientHello (yet?) */
+ if( buf[1] != 0 ||
+ msg_len != ssl_hs_hdr_len( ssl ) + ( ( buf[2] << 8 ) | buf[3] ) )
+ {
+ SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+ return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
+ }
+
#if defined(POLARSSL_SSL_PROTO_DTLS)
if( ssl->transport == SSL_TRANSPORT_DATAGRAM )
{
- /* 1 (type) + 3 (len) + 2 (seq) + 3 (frag_offset) + 3 (frag_len) */
- if( msg_len < 12 )
- {
- SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
- return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
- }
-
/*
* Copy the client's handshake message_seq on initial handshakes
*/
@@ -1318,68 +1340,41 @@
/*
* For now we don't support fragmentation, so make sure
* fragment_offset == 0 and fragment_length == length
- *
- * TODO: DTLS: support fragmentation??
- * Well, ClientHello is rarely much longer than 512 bytes
- * so it will probably never be fragmented anyway...
*/
if( ssl->in_msg[6] != 0 || ssl->in_msg[7] != 0 || ssl->in_msg[8] != 0 ||
memcmp( ssl->in_msg + 1, ssl->in_msg + 9, 3 ) != 0 )
{
- SSL_DEBUG_MSG( 1, ( "handshake fragmentation not supported" ) );
+ SSL_DEBUG_MSG( 1, ( "ClientHello fragmentation not supported" ) );
return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
}
-
- /* Remove the additional fields */
- memmove( buf + 4, buf + 12, msg_len - 12 );
- msg_len -= 8;
}
#endif /* POLARSSL_SSL_PROTO_DTLS */
+ buf += ssl_hs_hdr_len( ssl );
+ msg_len -= ssl_hs_hdr_len( ssl );
+
/*
- * SSL layer:
- * 0 . 0 handshake type
- * 1 . 3 handshake length
- * 4 . 5 protocol version
- * 6 . 37 random bytes (starting with 4 bytes of Unix time)
- * 38 . 38 session id length (1 byte)
- * 39 . 38+x session id
- * 39+x . 39+x DTLS only: cookie length (1 byte)
- * 40+x . .. DTSL only: cookie
+ * ClientHello layer:
+ * 0 . 1 protocol version
+ * 2 . 33 random bytes (starting with 4 bytes of Unix time)
+ * 34 . 35 session id length (1 byte)
+ * 35 . 34+x session id
+ * 35+x . 35+x DTLS only: cookie length (1 byte)
+ * 36+x . .. DTLS only: cookie
* .. . .. ciphersuite list length (2 bytes)
* .. . .. ciphersuite list
* .. . .. compression alg. list length (1 byte)
* .. . .. compression alg. list
* .. . .. extensions length (2 bytes, optional)
* .. . .. extensions (optional)
- *
- * Minimal length (with everything empty and extensions ommitted) is
- * 4 + 2 + 32 + 1 + 2 + 1 = 42 bytes. Check that first, so that we can
- * read at least up to session id length without worrying.
*/
/*
- * Check the handshake type and message length
+ * Minimal length (with everything empty and extensions ommitted) is
+ * 2 + 32 + 1 + 2 + 1 = 38 bytes. Check that first, so that we can
+ * read at least up to session id length without worrying.
*/
- if( msg_len < 42 )
- {
- SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
- return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
- }
-
- SSL_DEBUG_MSG( 3, ( "client hello v3, handshake type: %d", buf[0] ) );
-
- if( buf[0] != SSL_HS_CLIENT_HELLO )
- {
- SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
- return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
- }
-
- SSL_DEBUG_MSG( 3, ( "client hello v3, handshake len.: %d",
- ( buf[1] << 16 ) | ( buf[2] << 8 ) | buf[3] ) );
-
- if( buf[1] != 0 ||
- msg_len != (unsigned int) 4 + ( ( buf[2] << 8 ) | buf[3] ) )
+ if( msg_len < 38 )
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
@@ -1388,11 +1383,10 @@
/*
* Check and save the protocol version
*/
- SSL_DEBUG_MSG( 3, ( "client hello v3, max. version: [%d:%d]",
- buf[4], buf[5] ) );
+ SSL_DEBUG_BUF( 3, "client hello, version", buf, 2 );
ssl_read_version( &ssl->major_ver, &ssl->minor_ver,
- ssl->transport, buf + 4 );
+ ssl->transport, buf );
ssl->handshake->max_major_ver = ssl->major_ver;
ssl->handshake->max_minor_ver = ssl->minor_ver;
@@ -1422,30 +1416,28 @@
/*
* Save client random (inc. Unix time)
*/
- SSL_DEBUG_BUF( 3, "client hello, random bytes",
- buf + 6, 32 );
+ SSL_DEBUG_BUF( 3, "client hello, random bytes", buf + 2, 32 );
- memcpy( ssl->handshake->randbytes, buf + 6, 32 );
+ memcpy( ssl->handshake->randbytes, buf + 2, 32 );
/*
* Check the session ID length and save session ID
*/
- sess_len = buf[38];
+ sess_len = buf[34];
if( sess_len > sizeof( ssl->session_negotiate->id ) ||
- sess_len + 38 + 2 > msg_len ) /* 2 for cipherlist length field */
+ sess_len + 34 + 2 > msg_len ) /* 2 for cipherlist length field */
{
SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
}
- SSL_DEBUG_BUF( 3, "client hello, session id",
- buf + 39, sess_len );
+ SSL_DEBUG_BUF( 3, "client hello, session id", buf + 35, sess_len );
ssl->session_negotiate->length = sess_len;
memset( ssl->session_negotiate->id, 0,
sizeof( ssl->session_negotiate->id ) );
- memcpy( ssl->session_negotiate->id, buf + 39,
+ memcpy( ssl->session_negotiate->id, buf + 35,
ssl->session_negotiate->length );
/*
@@ -1454,7 +1446,7 @@
#if defined(POLARSSL_SSL_PROTO_DTLS)
if( ssl->transport == SSL_TRANSPORT_DATAGRAM )
{
- cookie_offset = 39 + sess_len;
+ cookie_offset = 35 + sess_len;
cookie_len = buf[cookie_offset];
if( cookie_offset + 1 + cookie_len + 2 > msg_len )
@@ -1506,7 +1498,7 @@
ciph_offset = cookie_offset + 1 + cookie_len;
else
#endif
- ciph_offset = 39 + sess_len;
+ ciph_offset = 35 + sess_len;
ciph_len = ( buf[ciph_offset + 0] << 8 )
| ( buf[ciph_offset + 1] );
