ipvs: fix info leak in getsockopt(IP_VS_SO_GET_TIMEOUT)

If at least one of CONFIG_IP_VS_PROTO_TCP or CONFIG_IP_VS_PROTO_UDP is
not set, __ip_vs_get_timeouts() does not fully initialize the structure
that gets copied to userland and that for leaks up to 12 bytes of kernel
stack. Add an explicit memset(0) before passing the structure to
__ip_vs_get_timeouts() to avoid the info leak.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Wensong Zhang <wensong@linux-vs.org>
Cc: Simon Horman <horms@verge.net.au>
Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 84444dda194b61806efaeadde4c2458f502d8283..72bf32a84874718927a4bcbdc2e26395be00bdd8 100644 (file)
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -2759,6 +2759,7 @@ do_ip_vs_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
        {
                struct ip_vs_timeout_user t;
 
+               memset(&t, 0, sizeof(t));
                __ip_vs_get_timeouts(net, &t);
                if (copy_to_user(user, &t, sizeof(t)) != 0)
                        ret = -EFAULT;