diff options
| author | Ying Hsu <yinghsu@chromium.org> | 2023-05-31 06:44:56 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-06-14 12:16:46 +0300 |
| commit | 0bf9d8f4e7e010cccd2aba164773f0ab9d1963e6 (patch) | |
| tree | 3d3ed39140ed8b1a1f28057cbd8326b662dfa377 /net | |
| parent | f202d27efbc76851fbe08ddea378123e234f11a3 (diff) | |
| download | linux-0bf9d8f4e7e010cccd2aba164773f0ab9d1963e6.tar.xz | |
Bluetooth: Fix l2cap_disconnect_req deadlock
[ Upstream commit 02c5ea5246a44d6ffde0fddebfc1d56188052976 ]
L2CAP assumes that the locks conn->chan_lock and chan->lock are
acquired in the order conn->chan_lock, chan->lock to avoid
potential deadlock.
For example, l2sock_shutdown acquires these locks in the order:
mutex_lock(&conn->chan_lock)
l2cap_chan_lock(chan)
However, l2cap_disconnect_req acquires chan->lock in
l2cap_get_chan_by_scid first and then acquires conn->chan_lock
before calling l2cap_chan_del. This means that these locks are
acquired in unexpected order, which leads to potential deadlock:
l2cap_chan_lock(c)
mutex_lock(&conn->chan_lock)
This patch releases chan->lock before acquiring the conn_chan_lock
to avoid the potential deadlock.
Fixes: a2a9339e1c9d ("Bluetooth: L2CAP: Fix use-after-free in l2cap_disconnect_{req,rsp}")
Signed-off-by: Ying Hsu <yinghsu@chromium.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/bluetooth/l2cap_core.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 24d075282996..e54e2aeb2a89 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -4664,7 +4664,9 @@ static inline int l2cap_disconnect_req(struct l2cap_conn *conn, chan->ops->set_shutdown(chan); + l2cap_chan_unlock(chan); mutex_lock(&conn->chan_lock); + l2cap_chan_lock(chan); l2cap_chan_del(chan, ECONNRESET); mutex_unlock(&conn->chan_lock); @@ -4703,7 +4705,9 @@ static inline int l2cap_disconnect_rsp(struct l2cap_conn *conn, return 0; } + l2cap_chan_unlock(chan); mutex_lock(&conn->chan_lock); + l2cap_chan_lock(chan); l2cap_chan_del(chan, 0); mutex_unlock(&conn->chan_lock); |