Fix issue with error check during handshake defragmentation

This check made sense without defragmentation but since now
it's valid to have message less than the minimum size as
part of the bigger fragmented message.

Signed-off-by: Waleed Elmelegy <[email protected]>

Author: waleed-elmelegy-arm

library/ssl_msg.c

@@ -3219,7 +3219,7 @@ static uint32_t ssl_get_hs_total_len(mbedtls_ssl_context const *ssl)
 
 int mbedtls_ssl_prepare_handshake_record(mbedtls_ssl_context *ssl)
 {
-    if (ssl->in_msglen < mbedtls_ssl_hs_hdr_len(ssl)) {
+    if (ssl->in_msglen < mbedtls_ssl_hs_hdr_len(ssl) && ssl->in_hsfraglen == 0) {
         MBEDTLS_SSL_DEBUG_MSG(1, ("handshake message too short: %" MBEDTLS_PRINTF_SIZET,
                                   ssl->in_msglen));
         return MBEDTLS_ERR_SSL_INVALID_RECORD;