From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Fri, 6 May 2022 12:32:37 +0000 (+0900)
Subject: resolve: first increment the reference counter
X-Git-Tag: v251-rc3~10^2~4
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=4ce30e4de05971ea93bc727695000d0025eb1591;p=thirdparty%2Fsystemd.git

resolve: first increment the reference counter

When `exist->rr` and `rr` point to the same object, then it may be freed by
the `dns_resource_record_unref()`.
---

diff --git a/src/resolve/resolved-dns-answer.c b/src/resolve/resolved-dns-answer.c
index 479af69d0fc..bbc1bdeecda 100644
--- a/src/resolve/resolved-dns-answer.c
+++ b/src/resolve/resolved-dns-answer.c
@@ -169,8 +169,9 @@ int dns_answer_add(
 
                 /* Entry already exists, keep the entry with the higher TTL. */
                 if (rr->ttl > exist->rr->ttl) {
+                        dns_resource_record_ref(rr);
                         dns_resource_record_unref(exist->rr);
-                        exist->rr = dns_resource_record_ref(rr); /* lgtm [cpp/inconsistent-null-check] */
+                        exist->rr = rr;
 
                         /* Update RRSIG and RR at the same time */
                         if (rrsig) {