From: Frank Denis <github@pureftpd.org>
Date: Sun, 20 Nov 2016 16:55:09 +0000 (+0100)
Subject: Do not allow empty names in `ldns_dname_new()`
X-Git-Tag: release-1.7.0-rc1~32^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F1%2Fhead;p=thirdparty%2Fldns.git

Do not allow empty names in `ldns_dname_new()`

A name has to be at least 1 byte, so return `NULL` if this is not the case.

Before that change, we had a paradoxical situation where
`ldns_dname_new(0, NULL)` returned a valid RDF pointer, but trying to use
that pointer with functions such as `ldns_rdf_print()` had an undefined
behavior.
---

diff --git a/dname.c b/dname.c
index 6701ba7d..1c41b7c7 100644
--- a/dname.c
+++ b/dname.c
@@ -251,6 +251,9 @@ ldns_dname_new(uint16_t s, void *d)
 {
         ldns_rdf *rd;
 
+        if (!s || !d) {
+                return NULL;
+        }
         rd = LDNS_MALLOC(ldns_rdf);
         if (!rd) {
                 return NULL;