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[Openvpn-devel,v2] dns: Fix memory leak in dns_server_addr_parse

Message ID 20260618061835.16448-1-gert@greenie.muc.de
State New
Headers
Series [Openvpn-devel,v2] dns: Fix memory leak in dns_server_addr_parse |

Commit Message

Gert Doering June 18, 2026, 6:18 a.m. UTC 
  From: saddamr3e <saddamr3e@gmail.com>

When the DNS server's address count is already full (exceeds the
limit of 8), the function returned early without freeing the
successfully resolved addrinfo struct. Fix this by checking the
limit before executing the DNS lookup.

Github: OpenVPN/openvpn#1055
Change-Id: I7ec318c86af994284d1c6272e3bbe2b1ede160fd
Signed-off-by: saddamr3e <saddamr3e@gmail.com>
Acked-by: Heiko Hund <heiko@openvpn.net>
Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1712
---

This change was reviewed on Gerrit and approved by at least one
developer. I request to merge it to master.

Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1712
This mail reflects revision 2 of this Change.

Acked-by according to Gerrit (reflected above):
Heiko Hund <heiko@openvpn.net>

Comments

Gert Doering June 18, 2026, 8:37 a.m. UTC | #1 
Thanks for the report and the patch.  Heiko has formally reviewed it, and
our buildbot framework has tested that all --dns using tests still work.

Antonio remarked that the "overflow" test could be moved further to the
start of the function - no need for all the address arithmetics if we
already know we're full.  But that's an optimization / beautification
we can do independently of this mem-leak fix.

Your patch has been applied to the master and release/2.7 branch (bugfix).

commit 154e8a520b3bd639fb137c1ba73ce8a80818d08d (master)
commit 7f1d68ae651b0dece0044b19376bf8ed8213e764 (release/2.7)
Author: saddamr3e
Date:   Thu Jun 18 08:18:28 2026 +0200

     dns: Fix memory leak in dns_server_addr_parse

     Signed-off-by: saddamr3e <saddamr3e@gmail.com>
     Acked-by: Heiko Hund <heiko@openvpn.net>
     Gerrit URL: https://gerrit.openvpn.net/c/openvpn/+/1712
     Message-Id: <20260618061835.16448-1-gert@greenie.muc.de>
     URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg37209.html
     Signed-off-by: Gert Doering <gert@greenie.muc.de>


--
kind regards,

Gert Doering
diff mbox series

Patch

diff --git a/src/openvpn/dns.c b/src/openvpn/dns.c
index 954ed52..1465cdf 100644
--- a/src/openvpn/dns.c
+++ b/src/openvpn/dns.c
@@ -114,13 +114,13 @@ 
         addr = addrcopy;
     }
 
-    struct addrinfo *ai = NULL;
-    if (openvpn_getaddrinfo(0, addr, NULL, 0, NULL, af, &ai) != 0)
+    if (server->addr_count >= SIZE(server->addr))
     {
         return false;
     }
 
-    if (server->addr_count >= SIZE(server->addr))
+    struct addrinfo *ai = NULL;
+    if (openvpn_getaddrinfo(0, addr, NULL, 0, NULL, af, &ai) != 0)
     {
         return false;
     }