path: root/net/sched/act_sample.c
diff options
authorDmytro Linkin <dmitrolin@mellanox.com>2019-08-01 13:02:51 +0000
committerDavid S. Miller <davem@davemloft.net>2019-08-05 10:59:14 -0700
commit7be8ef2cdbfe41a2e524b7c6cc3f8e6cfaa906e4 (patch)
tree42b36459934917001e8ed83595d238924120b3c9 /net/sched/act_sample.c
parentnet: dsa: mv88e6xxx: drop adjust_link to enabled phylink (diff)
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 <dmitrolin@mellanox.com> Signed-off-by: Vlad Buslov <vladbu@mellanox.com> Acked-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to '')
1 files changed, 5 insertions, 5 deletions
diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c
index 274d7a0c0e25..595308d60133 100644
--- a/net/sched/act_sample.c
+++ b/net/sched/act_sample.c
@@ -41,8 +41,8 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla,
struct tc_action_net *tn = net_generic(net, sample_net_id);
struct nlattr *tb[TCA_SAMPLE_MAX + 1];
struct psample_group *psample_group;
+ u32 psample_group_num, rate, index;
struct tcf_chain *goto_ch = NULL;
- u32 psample_group_num, rate;
struct tc_sample *parm;
struct tcf_sample *s;
bool exists = false;
@@ -59,8 +59,8 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla,
return -EINVAL;
parm = nla_data(tb[TCA_SAMPLE_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 < 0)
return err;
exists = err;
@@ -68,10 +68,10 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla,
return 0;
if (!exists) {
- ret = tcf_idr_create(tn, parm->index, est, a,
+ ret = tcf_idr_create(tn, index, est, a,
&act_sample_ops, bind, true);
if (ret) {
- tcf_idr_cleanup(tn, parm->index);
+ tcf_idr_cleanup(tn, index);
return ret;