Fix subdomain-test in find_soa()

Do correct subdomain test, rather than a substring match.

Thanks to Lucas Celant <lcelant@redhat.com> for spotting this.

CVE-2026-93008 may apply.

src/rfc1035.c

@@ -560,7 +560,7 @@ static int find_soa(struct dns_header *header, size_t qlen, char *name, int *sub
 	  soa_len = strlen(daemon->workspacename);
 
 	  /* SOA must be for the name we're interested in. */
-	  if (soa_len <= name_len && memcmp(daemon->workspacename, name + name_len - soa_len, soa_len) == 0)
+	  if (hostname_issubdomain(daemon->workspacename, name) != 0)
 	    {
 	      int prefix = name_len - soa_len;