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Message-Id: <20220607134709.373344-1-lee.jones@linaro.org>
Date: Tue, 7 Jun 2022 14:47:09 +0100
From: Lee Jones <lee.jones@...aro.org>
To: lee.jones@...aro.org
Cc: linux-kernel@...r.kernel.org, stable@...nel.org,
Marcel Holtmann <marcel@...tmann.org>,
Johan Hedberg <johan.hedberg@...il.com>,
Luiz Augusto von Dentz <luiz.dentz@...il.com>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
linux-bluetooth@...r.kernel.org, netdev@...r.kernel.org
Subject: [PATCH 1/1] Bluetooth: Use chan_list_lock to protect the whole put/destroy invokation
This change prevents a use-after-free caused by one of the worker
threads starting up (see below) *after* the final channel reference
has been put() during sock_close() but *before* the references to the
channel have been destroyed.
refcount_t: increment on 0; use-after-free.
BUG: KASAN: use-after-free in refcount_dec_and_test+0x20/0xd0
Read of size 4 at addr ffffffc114f5bf18 by task kworker/u17:14/705
CPU: 4 PID: 705 Comm: kworker/u17:14 Tainted: G S W 4.14.234-00003-g1fb6d0bd49a4-dirty #28
Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM sm8150 Flame DVT (DT)
Workqueue: hci0 hci_rx_work
Call trace:
dump_backtrace+0x0/0x378
show_stack+0x20/0x2c
dump_stack+0x124/0x148
print_address_description+0x80/0x2e8
__kasan_report+0x168/0x188
kasan_report+0x10/0x18
__asan_load4+0x84/0x8c
refcount_dec_and_test+0x20/0xd0
l2cap_chan_put+0x48/0x12c
l2cap_recv_frame+0x4770/0x6550
l2cap_recv_acldata+0x44c/0x7a4
hci_acldata_packet+0x100/0x188
hci_rx_work+0x178/0x23c
process_one_work+0x35c/0x95c
worker_thread+0x4cc/0x960
kthread+0x1a8/0x1c4
ret_from_fork+0x10/0x18
Cc: stable@...nel.org
Cc: Marcel Holtmann <marcel@...tmann.org>
Cc: Johan Hedberg <johan.hedberg@...il.com>
Cc: Luiz Augusto von Dentz <luiz.dentz@...il.com>
Cc: "David S. Miller" <davem@...emloft.net>
Cc: Eric Dumazet <edumazet@...gle.com>
Cc: Jakub Kicinski <kuba@...nel.org>
Cc: Paolo Abeni <pabeni@...hat.com>
Cc: linux-bluetooth@...r.kernel.org
Cc: netdev@...r.kernel.org
Signed-off-by: Lee Jones <lee.jones@...aro.org>
---
net/bluetooth/l2cap_core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index ae78490ecd3d4..82279c5919fd8 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -483,9 +483,7 @@ static void l2cap_chan_destroy(struct kref *kref)
BT_DBG("chan %p", chan);
- write_lock(&chan_list_lock);
list_del(&chan->global_l);
- write_unlock(&chan_list_lock);
kfree(chan);
}
@@ -501,7 +499,9 @@ void l2cap_chan_put(struct l2cap_chan *c)
{
BT_DBG("chan %p orig refcnt %u", c, kref_read(&c->kref));
+ write_lock(&chan_list_lock);
kref_put(&c->kref, l2cap_chan_destroy);
+ write_unlock(&chan_list_lock);
}
EXPORT_SYMBOL_GPL(l2cap_chan_put);
--
2.36.1.255.ge46751e96f-goog
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