From f6bfc46da6292b630ba389592123f0dd02066172 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 17 Jul 2015 22:38:43 +0200 Subject: [PATCH] sched: cls_bpf: fix panic on filter replace The following test case causes a NULL pointer dereference in cls_bpf: FOO="1,6 0 0 4294967295," tc filter add dev foo parent 1: bpf bytecode "$FOO" flowid 1:1 action ok tc filter replace dev foo parent 1: pref 49152 handle 0x1 \ bpf bytecode "$FOO" flowid 1:1 action drop The problem is that commit 1f947bf151e9 ("net: sched: rcu'ify cls_bpf") accidentally swapped the arguments of list_replace_rcu(), the old element needs to be the first argument and the new element the second. Fixes: 1f947bf151e9 ("net: sched: rcu'ify cls_bpf") Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- net/sched/cls_bpf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c index c79ecfd36e0f..e5168f8b9640 100644 --- a/net/sched/cls_bpf.c +++ b/net/sched/cls_bpf.c @@ -378,7 +378,7 @@ static int cls_bpf_change(struct net *net, struct sk_buff *in_skb, goto errout; if (oldprog) { - list_replace_rcu(&prog->link, &oldprog->link); + list_replace_rcu(&oldprog->link, &prog->link); tcf_unbind_filter(tp, &oldprog->res); call_rcu(&oldprog->rcu, __cls_bpf_delete_prog); } else {