Alter the check

Alter the check since 0 md size is an error.

Signed-off-by: Jiasheng Jiang <jiasheng@purdue.edu>

Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
(Merged from #23940)

ssl/ssl_lib.c

@@ -297,7 +297,7 @@ static int dane_tlsa_add(SSL_DANE *dane,
 
     if (md != NULL) {
         mdsize = EVP_MD_get_size(md);
-        if (mdsize < 0 || dlen != (size_t)mdsize) {
+        if (mdsize <= 0 || dlen != (size_t)mdsize) {
             ERR_raise(ERR_LIB_SSL, SSL_R_DANE_TLSA_BAD_DIGEST_LENGTH);
             return 0;
         }