From 7be8ef2cdbfe41a2e524b7c6cc3f8e6cfaa906e4 Mon Sep 17 00:00:00 2001 From: Dmytro Linkin Date: Thu, 1 Aug 2019 13:02:51 +0000 Subject: net: sched: use temporary variable for actions indexes Currently init call of all actions (except ipt) init their 'parm' structure as a direct pointer to nla data in skb. This leads to race condition when some of the filter actions were initialized successfully (and were assigned with idr action index that was written directly into nla data), but then were deleted and retried (due to following action module missing or classifier-initiated retry), in which case action init code tries to insert action to idr with index that was assigned on previous iteration. During retry the index can be reused by another action that was inserted concurrently, which causes unintended action sharing between filters. To fix described race condition, save action idr index to temporary stack-allocated variable instead on nla data. Fixes: 0190c1d452a9 ("net: sched: atomically check-allocate action") Signed-off-by: Dmytro Linkin Signed-off-by: Vlad Buslov Acked-by: Cong Wang Signed-off-by: David S. Miller --- net/sched/act_csum.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'net/sched/act_csum.c') diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c index 621fb22ce2a9..9b9288267a54 100644 --- a/net/sched/act_csum.c +++ b/net/sched/act_csum.c @@ -52,6 +52,7 @@ static int tcf_csum_init(struct net *net, struct nlattr *nla, struct tc_csum *parm; struct tcf_csum *p; int ret = 0, err; + u32 index; if (nla == NULL) return -EINVAL; @@ -64,13 +65,13 @@ static int tcf_csum_init(struct net *net, struct nlattr *nla, if (tb[TCA_CSUM_PARMS] == NULL) return -EINVAL; parm = nla_data(tb[TCA_CSUM_PARMS]); - - err = tcf_idr_check_alloc(tn, &parm->index, a, bind); + index = parm->index; + err = tcf_idr_check_alloc(tn, &index, a, bind); if (!err) { - ret = tcf_idr_create(tn, parm->index, est, a, + ret = tcf_idr_create(tn, index, est, a, &act_csum_ops, bind, true); if (ret) { - tcf_idr_cleanup(tn, parm->index); + tcf_idr_cleanup(tn, index); return ret; } ret = ACT_P_CREATED; -- cgit v1.2.1 From 981471bd3abf4d572097645d765391533aac327d Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Sun, 25 Aug 2019 10:01:32 -0700 Subject: net_sched: fix a NULL pointer deref in ipt action The net pointer in struct xt_tgdtor_param is not explicitly initialized therefore is still NULL when dereferencing it. So we have to find a way to pass the correct net pointer to ipt_destroy_target(). The best way I find is just saving the net pointer inside the per netns struct tcf_idrinfo, which could make this patch smaller. Fixes: 0c66dc1ea3f0 ("netfilter: conntrack: register hooks in netns when needed by ruleset") Reported-and-tested-by: itugrok@yahoo.com Cc: Jamal Hadi Salim Cc: Jiri Pirko Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- net/sched/act_csum.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/sched/act_csum.c') diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c index 9b9288267a54..d3cfad88dc3a 100644 --- a/net/sched/act_csum.c +++ b/net/sched/act_csum.c @@ -714,7 +714,7 @@ static __net_init int csum_init_net(struct net *net) { struct tc_action_net *tn = net_generic(net, csum_net_id); - return tc_action_net_init(tn, &act_csum_ops); + return tc_action_net_init(net, tn, &act_csum_ops); } static void __net_exit csum_exit_net(struct list_head *net_list) -- cgit v1.2.1