[Minor] Fix parsing of the very long TXT records

diff --git a/contrib/librdns/parse.c b/contrib/librdns/parse.c
index 1a9c01838d8f64bac59621f3b49982f89da900df..e9fb85e9849c1c7700b5eaff70f754a7aecaa3b2 100644 (file)
--- a/contrib/librdns/parse.c
+++ b/contrib/librdns/parse.c
@@ -351,10 +351,6 @@ rdns_parse_rr (struct rdns_resolver *resolver,
        case DNS_T_TXT:
        case DNS_T_SPF:
                if (datalen <= *remain) {
-                       if (datalen > UINT16_MAX / 2) {
-                               rdns_info ("too large datalen; domain %s", rep->requested_name);
-                               return -1;
-                       }
                        elt->content.txt.data = malloc(datalen + 1);
                        if (elt->content.txt.data == NULL) {
                                rdns_err ("failed to allocate %d bytes for TXT record; domain %s",
@@ -417,20 +413,24 @@ rdns_parse_rr (struct rdns_resolver *resolver,
                        rdns_info ("stripped dns reply while reading TLSA record; domain %s", rep->requested_name);
                        return -1;
                }
-               if (datalen > UINT16_MAX / 2) {
+
+               if (datalen > *remain) {
                        rdns_info ("too large datalen; domain %s", rep->requested_name);
                        return -1;
                }
+
                GET8 (elt->content.tlsa.usage);
                GET8 (elt->content.tlsa.selector);
                GET8 (elt->content.tlsa.match_type);
                datalen -= 3;
+
                elt->content.tlsa.data = malloc (datalen);
                if (elt->content.tlsa.data == NULL) {
                        rdns_err ("failed to allocate %d bytes for TLSA record; domain %s",
                                        (int)datalen + 1, rep->requested_name);
                        return -1;
                }
+
                elt->content.tlsa.datalen = datalen;
                memcpy (elt->content.tlsa.data, p, datalen);
                p += datalen;