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| author | Vlad Buslov <vladbu@nvidia.com> | 2021-04-07 17:36:03 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-04-08 22:47:33 +0200 |
| commit | 87c750e8c38bce706eb32e4d8f1e3402f2cebbd4 (patch) | |
| tree | 4d5c73cbd7a1b764b7af10521233a872b36c42c7 /net/sched/cls_api.c | |
| parent | Revert "net: sched: bump refcount for new action in ACT replace mode" (diff) | |
| download | linux-87c750e8c38bce706eb32e4d8f1e3402f2cebbd4.tar.xz linux-87c750e8c38bce706eb32e4d8f1e3402f2cebbd4.zip | |
net: sched: fix action overwrite reference counting
Action init code increments reference counter when it changes an action.
This is the desired behavior for cls API which needs to obtain action
reference for every classifier that points to action. However, act API just
needs to change the action and releases the reference before returning.
This sequence breaks when the requested action doesn't exist, which causes
act API init code to create new action with specified index, but action is
still released before returning and is deleted (unless it was referenced
concurrently by cls API).
Reproduction:
$ sudo tc actions ls action gact
$ sudo tc actions change action gact drop index 1
$ sudo tc actions ls action gact
Extend tcf_action_init() to accept 'init_res' array and initialize it with
action->ops->init() result. In tcf_action_add() remove pointers to created
actions from actions array before passing it to tcf_action_put_many().
Fixes: cae422f379f3 ("net: sched: use reference counting action init")
Reported-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/cls_api.c')
| -rw-r--r-- | net/sched/cls_api.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 9332ec6863e8..9ecb91ebf094 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -3040,6 +3040,7 @@ int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb, { #ifdef CONFIG_NET_CLS_ACT { + int init_res[TCA_ACT_MAX_PRIO] = {}; struct tc_action *act; size_t attr_size = 0; @@ -3051,8 +3052,8 @@ int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb, return PTR_ERR(a_o); act = tcf_action_init_1(net, tp, tb[exts->police], rate_tlv, "police", ovr, - TCA_ACT_BIND, a_o, rtnl_held, - extack); + TCA_ACT_BIND, a_o, init_res, + rtnl_held, extack); if (IS_ERR(act)) { module_put(a_o->owner); return PTR_ERR(act); @@ -3067,8 +3068,8 @@ int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb, err = tcf_action_init(net, tp, tb[exts->action], rate_tlv, NULL, ovr, TCA_ACT_BIND, - exts->actions, &attr_size, - rtnl_held, extack); + exts->actions, init_res, + &attr_size, rtnl_held, extack); if (err < 0) return err; exts->nr_actions = err; |