From: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Date: Mon, 8 Apr 2024 10:21:21 +0000 (+0200)
Subject: lxc/network: handle non-existing sysctl <ifname>/disable_ipv6
X-Git-Tag: v6.0.1~18
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=bd8d5b747fc7256be97df6381e1f6e6451f8e00c;p=thirdparty%2Flxc.git

lxc/network: handle non-existing sysctl <ifname>/disable_ipv6

Skip writting to /proc/sys/net/ipv6/conf/<ifname>/disable_ipv6
if it does not exist.

Fixes: #4431
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
---

diff --git a/src/lxc/network.c b/src/lxc/network.c
index 09666a76c..2a6ba6cb4 100644
--- a/src/lxc/network.c
+++ b/src/lxc/network.c
@@ -722,15 +722,15 @@ static int netdev_configure_server_veth(struct lxc_handler *handler, struct lxc_
 		if (disable_ipv6_fd < 0 && errno != ENOENT) {
 			SYSERROR("Failed to disable IPv6 link-local addresses for veth pair \"%s\"", veth1);
 			goto out_delete;
+		} else if (disable_ipv6_fd >= 0) {
+			err = write(disable_ipv6_fd, "1", 1);
+			if (err < 0) {
+				SYSERROR("Failed to disable IPv6 link-local addresses for veth pair \"%s\"", veth1);
+				goto out_delete;
+			}
+			close(disable_ipv6_fd);
 		}
 
-		err = write(disable_ipv6_fd, "1", 1);
-		if (err < 0) {
-			SYSERROR("Failed to disable IPv6 link-local addresses for veth pair \"%s\"", veth1);
-			goto out_delete;
-		}
-		close(disable_ipv6_fd);
-
 		if (!lxc_nic_exists(netdev->link)) {
 			SYSERROR("Failed to attach \"%s\" to bridge \"%s\", bridge interface doesn't exist", veth1, netdev->link);
 			goto out_delete;