diff options
| author | Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr> | 2026-10-08 18:13:49 +0000 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2026-10-15 13:00:02 +0200 |
| commit | 7b16eb911091aae237a8673da94e4dfb9cd21d54 (patch) | |
| tree | 28a883138c74cdd361842c3eca476fca2f0c8dad | |
| parent | 8070ed578b6b9134e045627fb745c887a806d46e (diff) | |
net/sched: fix use-after-free in __tcf_action_put()
__tcf_action_put() decrements the reference count before decrementing the
binding count. Another thread can free the action between these operations,
causing the binding-count update to access freed memory. KASAN reports it
as:
BUG: KASAN: slab-use-after-free in __tcf_action_put+0x327/0x340
Write of size 4 at addr ff11000000d46420 by task tc-put-pause/64
Hold the action IDR mutex across both counter updates and IDR removal,
keeping cleanup outside the lock.
Fixes: 16af6067392c ("net: sched: implement reference counted action release")
Cc: stable@vger.kernel.org
Assisted-by: LLM
Signed-off-by: Jérémy Jean <Jeremy.Jean@oss.cyber.gouv.fr>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20261008181348.527035-2-Jeremy.Jean@oss.cyber.gouv.fr
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
| -rw-r--r-- | net/sched/act_api.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/net/sched/act_api.c b/net/sched/act_api.c index e45a63be397c..9eb1dec14cb1 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -372,9 +372,10 @@ static int __tcf_action_put(struct tc_action *p, bool bind) { struct tcf_idrinfo *idrinfo = p->idrinfo; - if (refcount_dec_and_mutex_lock(&p->tcfa_refcnt, &idrinfo->lock)) { - if (bind) - atomic_dec(&p->tcfa_bindcnt); + mutex_lock(&idrinfo->lock); + if (bind) + atomic_dec(&p->tcfa_bindcnt); + if (refcount_dec_and_test(&p->tcfa_refcnt)) { idr_remove(&idrinfo->action_idr, p->tcfa_index); mutex_unlock(&idrinfo->lock); @@ -382,9 +383,7 @@ static int __tcf_action_put(struct tc_action *p, bool bind) return 1; } - if (bind) - atomic_dec(&p->tcfa_bindcnt); - + mutex_unlock(&idrinfo->lock); return 0; } |