From 4f8a881acc9d1adaf1e552349a0b1df28933a04c Mon Sep 17 00:00:00 2001 From: Xin Long Date: Fri, 18 Aug 2017 11:01:36 +0800 Subject: net: sched: fix NULL pointer dereference when action calls some targets As we know in some target's checkentry it may dereference par.entryinfo to check entry stuff inside. But when sched action calls xt_check_target, par.entryinfo is set with NULL. It would cause kernel panic when calling some targets. It can be reproduce with: # tc qd add dev eth1 ingress handle ffff: # tc filter add dev eth1 parent ffff: u32 match u32 0 0 action xt \ -j ECN --ecn-tcp-remove It could also crash kernel when using target CLUSTERIP or TPROXY. By now there's no proper value for par.entryinfo in ipt_init_target, but it can not be set with NULL. This patch is to void all these panics by setting it with an ipt_entry obj with all members = 0. Note that this issue has been there since the very beginning. Signed-off-by: Xin Long Acked-by: Pablo Neira Ayuso Signed-off-by: David S. Miller --- net/sched/act_ipt.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/sched/act_ipt.c') diff --git a/net/sched/act_ipt.c b/net/sched/act_ipt.c index d516ba8178b8..541707802a23 100644 --- a/net/sched/act_ipt.c +++ b/net/sched/act_ipt.c @@ -41,6 +41,7 @@ static int ipt_init_target(struct net *net, struct xt_entry_target *t, { struct xt_tgchk_param par; struct xt_target *target; + struct ipt_entry e = {}; int ret = 0; target = xt_request_find_target(AF_INET, t->u.user.name, @@ -52,6 +53,7 @@ static int ipt_init_target(struct net *net, struct xt_entry_target *t, memset(&par, 0, sizeof(par)); par.net = net; par.table = table; + par.entryinfo = &e; par.target = target; par.targinfo = t->data; par.hook_mask = hook; -- cgit v1.2.3