From c779441e5070e2268bdfe77f6e2e0de926c431e3 Mon Sep 17 00:00:00 2001 From: Fernando Fernandez Mancera Date: Mon, 22 Jun 2026 15:08:52 +0200 Subject: [PATCH] ipv6: fix error handling in disable_ipv6 sysctl When writing to the disable_ipv6 sysctl, if proc_dointvec() fails to parse the input, it returns a negative error code. The current implementation is overwriting that error for write operations. This results in a silent failure, it returns a successful write although the configuration was not modified at all. When modifying the "all" variant it can also modify the configuration of existing interfaces to the wrong value. Fix this by checking the return value of proc_dointvec() and returning early on failure. Fixes: 56d417b12e57 ("IPv6: Add 'autoconf' and 'disable_ipv6' module parameters") Reviewed-by: Nicolas Dichtel Signed-off-by: Fernando Fernandez Mancera Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260622130857.5115-2-fmancera@suse.de Signed-off-by: Jakub Kicinski --- net/ipv6/addrconf.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 1f21ccb55caa..c901b444a995 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -6467,6 +6467,8 @@ static int addrconf_sysctl_disable(const struct ctl_table *ctl, int write, lctl.data = &val; ret = proc_dointvec(&lctl, write, buffer, lenp, ppos); + if (ret) + return ret; if (write) ret = addrconf_disable_ipv6(ctl, valp, val);