From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 9 Dec 2015 16:41:33 +0000 (+0100)
Subject: resolved: refuse modifying DnsAnswer objects that have more than one reference
X-Git-Tag: v229~217^2~13
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=c296dd2eea308e9ef73eb81f31e9eeaa32c30895;p=thirdparty%2Fsystemd.git

resolved: refuse modifying DnsAnswer objects that have more than one reference

DnsAnswer objects should be considered immutable after having passed to
more than one user, i.e. with a reference counter > 1. Enforce that in
code, so that we can track down misuses easier.
---

diff --git a/src/resolve/resolved-dns-answer.c b/src/resolve/resolved-dns-answer.c
index 14cba39ad2a..f1f4d909ccf 100644
--- a/src/resolve/resolved-dns-answer.c
+++ b/src/resolve/resolved-dns-answer.c
@@ -81,6 +81,8 @@ int dns_answer_add(DnsAnswer *a, DnsResourceRecord *rr, int ifindex) {
 
         if (!a)
                 return -ENOSPC;
+        if (a->n_ref > 1)
+                return -EBUSY;
 
         for (i = 0; i < a->n_rrs; i++) {
                 if (a->items[i].ifindex != ifindex)