More ssl_parse_client_hello() adjustments
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index fd83ef2..59ff3ac 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -1192,39 +1192,46 @@
msg_len = ( ssl->in_len[0] << 8 ) | ssl->in_len[1];
- /*
- * Minimum length of a ClientHello is 42 plus headers (see below).
- */
- if( msg_len > SSL_MAX_CONTENT_LEN ||
- msg_len < 42 + ssl_hdr_len( ssl ) )
+ if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE )
{
- SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
- return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
- }
+ if( msg_len > SSL_MAX_CONTENT_LEN )
+ {
+ SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+ return( POLARSSL_ERR_SSL_BAD_HS_CLIENT_HELLO );
+ }
- if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE &&
- ( ret = ssl_fetch_input( ssl, ssl_hdr_len( ssl ) + msg_len ) ) != 0 )
+ if( ( ret = ssl_fetch_input( ssl, ssl_hdr_len( ssl ) + msg_len ) ) != 0 )
+ {
+ SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
+ return( ret );
+ }
+ }
+ else
{
- SSL_DEBUG_RET( 1, "ssl_fetch_input", ret );
- return( ret );
+ /* Set by ssl_read_record() */
+ msg_len = ssl->in_hslen;
}
buf = ssl->in_msg;
- if( ssl->renegotiation == SSL_INITIAL_HANDSHAKE )
- msg_len = ssl->in_left - ssl_hdr_len( ssl );
- else
- msg_len = ssl->in_msglen;
SSL_DEBUG_BUF( 4, "record contents", buf, msg_len );
ssl->handshake->update_checksum( ssl, buf, msg_len );
/*
- * For DTLS, we move data so that is looks like TLS handshake format
+ * 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.
*/
#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 );
+ }
+
// TODO: DTLS: check message_seq
/*
@@ -1242,6 +1249,7 @@
return( POLARSSL_ERR_SSL_FEATURE_UNAVAILABLE );
}
+ /* Remove the additional fields */
memmove( buf + 4, buf + 12, msg_len - 12 );
msg_len -= 8;
}
@@ -1265,13 +1273,19 @@
* .. . .. extensions (optional)
*
* Minimal length (with everything empty and extensions ommitted) is
- * 4 + 2 + 32 + 1 + 2 + 1 = 42 bytes, which has been checked already,
- * so we're fine until 'session id length' included.
+ * 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
*/
+ 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 )