From: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp
[ Upstream commit 2d2cb3066f2c90cd8ca540b36ba7a55e7f2406e0 ]
syzbot is reporting cancel_delayed_work() without INIT_DELAYED_WORK() at l2cap_chan_del() [1], for CONF_NOT_COMPLETE flag (which meant to prevent l2cap_chan_del() from calling cancel_delayed_work()) is cleared by timer which fires before l2cap_chan_del() is called by closing file descriptor created by socket(AF_BLUETOOTH, SOCK_STREAM, BTPROTO_L2CAP).
l2cap_bredr_sig_cmd(L2CAP_CONF_REQ) and l2cap_bredr_sig_cmd(L2CAP_CONF_RSP) are calling l2cap_ertm_init(chan), and they call l2cap_chan_ready() (which clears CONF_NOT_COMPLETE flag) only when l2cap_ertm_init(chan) succeeded.
l2cap_sock_init() does not call l2cap_ertm_init(chan), and it instead sets CONF_NOT_COMPLETE flag by calling l2cap_chan_set_defaults(). However, when connect() is requested, "command 0x0409 tx timeout" happens after 2 seconds from connect() request, and CONF_NOT_COMPLETE flag is cleared after 4 seconds from connect() request, for l2cap_conn_start() from l2cap_info_timeout() callback scheduled by
schedule_delayed_work(&conn->info_timer, L2CAP_INFO_TIMEOUT);
in l2cap_connect() is calling l2cap_chan_ready().
Fix this problem by initializing delayed works used by L2CAP_MODE_ERTM mode as soon as l2cap_chan_create() allocates a channel, like I did in commit be8597239379f0f5 ("Bluetooth: initialize skb_queue_head at l2cap_chan_create()").
Link: https://syzkaller.appspot.com/bug?extid=83672956c7aa6af698b3 [1] Reported-by: syzbot syzbot+83672956c7aa6af698b3@syzkaller.appspotmail.com Signed-off-by: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/bluetooth/l2cap_core.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index e45a12378bd1..75a76353525c 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -63,6 +63,9 @@ static void l2cap_send_disconn_req(struct l2cap_chan *chan, int err);
static void l2cap_tx(struct l2cap_chan *chan, struct l2cap_ctrl *control, struct sk_buff_head *skbs, u8 event); +static void l2cap_retrans_timeout(struct work_struct *work); +static void l2cap_monitor_timeout(struct work_struct *work); +static void l2cap_ack_timeout(struct work_struct *work);
static inline u8 bdaddr_type(u8 link_type, u8 bdaddr_type) { @@ -470,6 +473,9 @@ struct l2cap_chan *l2cap_chan_create(void) write_unlock(&chan_list_lock);
INIT_DELAYED_WORK(&chan->chan_timer, l2cap_chan_timeout); + INIT_DELAYED_WORK(&chan->retrans_timer, l2cap_retrans_timeout); + INIT_DELAYED_WORK(&chan->monitor_timer, l2cap_monitor_timeout); + INIT_DELAYED_WORK(&chan->ack_timer, l2cap_ack_timeout);
chan->state = BT_OPEN;
@@ -3154,10 +3160,6 @@ int l2cap_ertm_init(struct l2cap_chan *chan) chan->rx_state = L2CAP_RX_STATE_RECV; chan->tx_state = L2CAP_TX_STATE_XMIT;
- INIT_DELAYED_WORK(&chan->retrans_timer, l2cap_retrans_timeout); - INIT_DELAYED_WORK(&chan->monitor_timer, l2cap_monitor_timeout); - INIT_DELAYED_WORK(&chan->ack_timer, l2cap_ack_timeout); - skb_queue_head_init(&chan->srej_q);
err = l2cap_seq_list_init(&chan->srej_list, chan->tx_win);