From: Steffen Klassert <steffen.klassert@secunet.com>
To: David Miller <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
Steffen Klassert <steffen.klassert@secunet.com>,
<netdev@vger.kernel.org>
Subject: [PATCH 8/8] xfrm: policy: Fix doulbe free in xfrm_policy_timer
Date: Fri, 27 Mar 2020 09:10:07 +0100 [thread overview]
Message-ID: <20200327081007.1185-9-steffen.klassert@secunet.com> (raw)
In-Reply-To: <20200327081007.1185-1-steffen.klassert@secunet.com>
From: YueHaibing <yuehaibing@huawei.com>
After xfrm_add_policy add a policy, its ref is 2, then
xfrm_policy_timer
read_lock
xp->walk.dead is 0
....
mod_timer()
xfrm_policy_kill
policy->walk.dead = 1
....
del_timer(&policy->timer)
xfrm_pol_put //ref is 1
xfrm_pol_put //ref is 0
xfrm_policy_destroy
call_rcu
xfrm_pol_hold //ref is 1
read_unlock
xfrm_pol_put //ref is 0
xfrm_policy_destroy
call_rcu
xfrm_policy_destroy is called twice, which may leads to
double free.
Call Trace:
RIP: 0010:refcount_warn_saturate+0x161/0x210
...
xfrm_policy_timer+0x522/0x600
call_timer_fn+0x1b3/0x5e0
? __xfrm_decode_session+0x2990/0x2990
? msleep+0xb0/0xb0
? _raw_spin_unlock_irq+0x24/0x40
? __xfrm_decode_session+0x2990/0x2990
? __xfrm_decode_session+0x2990/0x2990
run_timer_softirq+0x5c5/0x10e0
Fix this by use write_lock_bh in xfrm_policy_kill.
Fixes: ea2dea9dacc2 ("xfrm: remove policy lock when accessing policy->walk.dead")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Timo Teräs <timo.teras@iki.fi>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
net/xfrm/xfrm_policy.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 297d1eb79e5c..96a8c452b63e 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -434,7 +434,9 @@ EXPORT_SYMBOL(xfrm_policy_destroy);
static void xfrm_policy_kill(struct xfrm_policy *policy)
{
+ write_lock_bh(&policy->lock);
policy->walk.dead = 1;
+ write_unlock_bh(&policy->lock);
atomic_inc(&policy->genid);
--
2.17.1
next prev parent reply other threads:[~2020-03-27 8:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-27 8:09 pull request (net): ipsec 2020-03-27 Steffen Klassert
2020-03-27 8:10 ` [PATCH 1/8] xfrm: handle NETDEV_UNREGISTER for xfrm device Steffen Klassert
2020-03-27 8:10 ` [PATCH 2/8] vti[6]: fix packet tx through bpf_redirect() in XinY cases Steffen Klassert
2020-03-27 8:10 ` [PATCH 3/8] xfrm: fix uctx len check in verify_sec_ctx_len Steffen Klassert
2020-03-27 8:10 ` [PATCH 4/8] xfrm: add the missing verify_sec_ctx_len check in xfrm_add_acquire Steffen Klassert
2020-03-27 8:10 ` [PATCH 5/8] ipv6: xfrm6_tunnel.c: Use built-in RCU list checking Steffen Klassert
2020-03-27 8:10 ` [PATCH 6/8] esp: remove the skb from the chain when it's enqueued in cryptd_wq Steffen Klassert
2020-03-27 8:10 ` [PATCH 7/8] vti6: Fix memory leak of skb if input policy check fails Steffen Klassert
2020-03-27 8:10 ` Steffen Klassert [this message]
2020-03-27 21:57 ` pull request (net): ipsec 2020-03-27 David Miller
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