From: Thomas Hindoe Paaboel Andersen <phomes@gmail.com>
Date: Sun, 3 Aug 2014 20:41:25 +0000 (+0200)
Subject: resolved: avoid possible dereference of null pointer
X-Git-Tag: v216~283
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=75cd513ef830d8e00d0d2d6a64917fec533315db

resolved: avoid possible dereference of null pointer

In dns_scope_make_reply_packet the structs q, answer, and soa can be
null. We should check for null before reading their fields.
---

diff --git a/src/resolve/resolved-dns-scope.c b/src/resolve/resolved-dns-scope.c
index 8d03049c1..0f654a610 100644
--- a/src/resolve/resolved-dns-scope.c
+++ b/src/resolve/resolved-dns-scope.c
@@ -412,7 +412,9 @@ static int dns_scope_make_reply_packet(
 
         assert(s);
 
-        if (q->n_keys <= 0 && answer->n_rrs <= 0 && soa->n_rrs <= 0)
+        if ((!q || q->n_keys <= 0)
+            && (!answer || answer->n_rrs <= 0)
+            && (!soa || soa->n_rrs <= 0))
                 return -EINVAL;
 
         r = dns_packet_new(&p, s->protocol, 0);