diff options
| author | Dmytro Linkin <dmitrolin@mellanox.com> | 2019-08-01 16:02:51 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-08-05 20:59:14 +0300 |
| commit | 7be8ef2cdbfe41a2e524b7c6cc3f8e6cfaa906e4 (patch) | |
| tree | 42b36459934917001e8ed83595d238924120b3c9 /net/sched/act_skbmod.c | |
| parent | 7fb5a711545d7d25fe9726a9ad277474dd83bd06 (diff) | |
| download | linux-7be8ef2cdbfe41a2e524b7c6cc3f8e6cfaa906e4.tar.xz | |
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 'net/sched/act_skbmod.c')
| -rw-r--r-- | net/sched/act_skbmod.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/net/sched/act_skbmod.c b/net/sched/act_skbmod.c index 4f07706eff07..7da3518e18ef 100644 --- a/net/sched/act_skbmod.c +++ b/net/sched/act_skbmod.c @@ -87,12 +87,12 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla, struct tcf_skbmod_params *p, *p_old; struct tcf_chain *goto_ch = NULL; struct tc_skbmod *parm; + u32 lflags = 0, index; struct tcf_skbmod *d; bool exists = false; u8 *daddr = NULL; u8 *saddr = NULL; u16 eth_type = 0; - u32 lflags = 0; int ret = 0, err; if (!nla) @@ -122,10 +122,11 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla, } parm = nla_data(tb[TCA_SKBMOD_PARMS]); + index = parm->index; if (parm->flags & SKBMOD_F_SWAPMAC) lflags = SKBMOD_F_SWAPMAC; - err = tcf_idr_check_alloc(tn, &parm->index, a, bind); + err = tcf_idr_check_alloc(tn, &index, a, bind); if (err < 0) return err; exists = err; @@ -136,15 +137,15 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla, if (exists) tcf_idr_release(*a, bind); else - tcf_idr_cleanup(tn, parm->index); + tcf_idr_cleanup(tn, index); return -EINVAL; } if (!exists) { - ret = tcf_idr_create(tn, parm->index, est, a, + ret = tcf_idr_create(tn, index, est, a, &act_skbmod_ops, bind, true); if (ret) { - tcf_idr_cleanup(tn, parm->index); + tcf_idr_cleanup(tn, index); return ret; } |