[PATCH AUTOSEL 5.4 13/29] Bluetooth: L2CAP: initialize delayed works at l2cap_chan_create()

[PATCH AUTOSEL 5.4 13/29] Bluetooth: L2CAP: initialize delayed works at l2cap_chan_create()

[Sasha Levin]

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 3682d2e1cd7d..442432f89be1 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -60,6 +60,9 @@ 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)
 {
@@ -475,6 +478,9 @@ 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;
 
@@ -3163,10 +3169,6 @@ 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);
-- 
2.35.1

[PATCH AUTOSEL 5.4 18/29] Bluetooth: hci_sysfs: Fix attempting to call device_add multiple times

[Sasha Levin]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

[ Upstream commit 448a496f760664d3e2e79466aa1787e6abc922b5 ]

device_add shall not be called multiple times as stated in its
documentation:

 'Do not call this routine or device_register() more than once for
 any device structure'

Syzkaller reports a bug as follows [1]:
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:33!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
[...]
Call Trace:
 <TASK>
 __list_add include/linux/list.h:69 [inline]
 list_add_tail include/linux/list.h:102 [inline]
 kobj_kset_join lib/kobject.c:164 [inline]
 kobject_add_internal+0x18f/0x8f0 lib/kobject.c:214
 kobject_add_varg lib/kobject.c:358 [inline]
 kobject_add+0x150/0x1c0 lib/kobject.c:410
 device_add+0x368/0x1e90 drivers/base/core.c:3452
 hci_conn_add_sysfs+0x9b/0x1b0 net/bluetooth/hci_sysfs.c:53
 hci_le_cis_estabilished_evt+0x57c/0xae0 net/bluetooth/hci_event.c:6799
 hci_le_meta_evt+0x2b8/0x510 net/bluetooth/hci_event.c:7110
 hci_event_func net/bluetooth/hci_event.c:7440 [inline]
 hci_event_packet+0x63d/0xfd0 net/bluetooth/hci_event.c:7495
 hci_rx_work+0xae7/0x1230 net/bluetooth/hci_core.c:4007
 process_one_work+0x991/0x1610 kernel/workqueue.c:2289
 worker_thread+0x665/0x1080 kernel/workqueue.c:2436
 kthread+0x2e4/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>

Link: https://syzkaller.appspot.com/bug?id=da3246e2d33afdb92d66bc166a0934c5b146404a
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Tested-by: Hawkins Jiawei <yin31149@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/bluetooth/hci_sysfs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c
index b69d88b88d2e..ccd2c377bf83 100644
--- a/net/bluetooth/hci_sysfs.c
+++ b/net/bluetooth/hci_sysfs.c
@@ -48,6 +48,9 @@ void hci_conn_add_sysfs(struct hci_conn *conn)
 
 	BT_DBG("conn %p", conn);
 
+	if (device_is_registered(&conn->dev))
+		return;
+
 	dev_set_name(&conn->dev, "%s:%d", hdev->name, conn->handle);
 
 	if (device_add(&conn->dev) < 0) {
-- 
2.35.1

[PATCH AUTOSEL 5.4 27/29] Bluetooth: L2CAP: Fix user-after-free

[Sasha Levin]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

[ Upstream commit 35fcbc4243aad7e7d020b7c1dfb14bb888b20a4f ]

This uses l2cap_chan_hold_unless_zero() after calling
__l2cap_get_chan_blah() to prevent the following trace:

Bluetooth: l2cap_core.c:static void l2cap_chan_destroy(struct kref
*kref)
Bluetooth: chan 0000000023c4974d
Bluetooth: parent 00000000ae861c08
==================================================================
BUG: KASAN: use-after-free in __mutex_waiter_is_first
kernel/locking/mutex.c:191 [inline]
BUG: KASAN: use-after-free in __mutex_lock_common
kernel/locking/mutex.c:671 [inline]
BUG: KASAN: use-after-free in __mutex_lock+0x278/0x400
kernel/locking/mutex.c:729
Read of size 8 at addr ffff888006a49b08 by task kworker/u3:2/389

Link: https://lore.kernel.org/lkml/20220622082716.478486-1-lee.jones@linaro.org
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sungwoo Kim <iam@sung-woo.kim>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/bluetooth/l2cap_core.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 442432f89be1..2d28b4e49b7a 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -4066,6 +4066,12 @@ static int l2cap_connect_create_rsp(struct l2cap_conn *conn,
 		}
 	}
 
+	chan = l2cap_chan_hold_unless_zero(chan);
+	if (!chan) {
+		err = -EBADSLT;
+		goto unlock;
+	}
+
 	err = 0;
 
 	l2cap_chan_lock(chan);
@@ -4095,6 +4101,7 @@ static int l2cap_connect_create_rsp(struct l2cap_conn *conn,
 	}
 
 	l2cap_chan_unlock(chan);
+	l2cap_chan_put(chan);
 
 unlock:
 	mutex_unlock(&conn->chan_lock);
-- 
2.35.1