Bluetooth: L2CAP: Fix l2cap_global_chan_by_psm regression

The patch d0be8347c623: "Bluetooth: L2CAP: Fix use-after-free caused
by l2cap_chan_put" from Jul 21, 2022, leads to the following Smatch
sta

Bluetooth: L2CAP: Fix l2cap_global_chan_by_psm regression

The patch d0be8347c623: "Bluetooth: L2CAP: Fix use-after-free caused
by l2cap_chan_put" from Jul 21, 2022, leads to the following Smatch
static checker warning:

net/bluetooth/l2cap_core.c:1977 l2cap_global_chan_by_psm()
error: we previously assumed 'c' could be null (see line 1996)

Fixes: d0be8347c623 ("Bluetooth: L2CAP: Fix use-after-free caused by l2cap_chan_put")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

show more ...

Bluetooth: L2CAP: Fix use-after-free caused by l2cap_chan_put

This fixes the following trace which is caused by hci_rx_work starting up
*after* the final channel reference has been put() during sock

Bluetooth: L2CAP: Fix use-after-free caused by l2cap_chan_put

This fixes the following trace which is caused by hci_rx_work starting up
*after* the final channel reference has been put() during sock_close() but
*before* the references to the channel have been destroyed, so instead
the code now rely on kref_get_unless_zero/l2cap_chan_hold_unless_zero to
prevent referencing a channel that is about to be 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@kernel.org
Reported-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Tested-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

show more ...

Bluetooth: use memset avoid memory leaks

Similar to the handling of l2cap_ecred_connect in commit d3715b2333e9
("Bluetooth: use memset avoid memory leaks"), we thought a patch
might be needed here a

Bluetooth: use memset avoid memory leaks

Similar to the handling of l2cap_ecred_connect in commit d3715b2333e9
("Bluetooth: use memset avoid memory leaks"), we thought a patch
might be needed here as well.

Use memset to initialize structs to prevent memory leaks
in l2cap_le_connect

Signed-off-by: Xiaohui Zhang <xiaohuizhang@ruc.edu.cn>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

show more ...

Bluetooth: Don't assign twice the same value

data.pid is set twice with the same value. Remove one of these redundant
calls.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed

Bluetooth: Don't assign twice the same value

data.pid is set twice with the same value. Remove one of these redundant
calls.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

show more ...

Bluetooth: use memset avoid memory leaks

Use memset to initialize structs to prevent memory leaks
in l2cap_ecred_connect

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Minghao Chi (CGEL

Bluetooth: use memset avoid memory leaks

Use memset to initialize structs to prevent memory leaks
in l2cap_ecred_connect

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Minghao Chi (CGEL ZTE) <chi.minghao@zte.com.cn>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

show more ...

Bluetooth: hci_sync: Add hci_le_create_conn_sync

This adds hci_le_create_conn_sync and make hci_le_connect use it instead
of queueing multiple commands which may conflict with the likes of
hci_updat

Bluetooth: hci_sync: Add hci_le_create_conn_sync

This adds hci_le_create_conn_sync and make hci_le_connect use it instead
of queueing multiple commands which may conflict with the likes of
hci_update_passive_scan which uses hci_cmd_sync_queue.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

show more ...

Bluetooth: Fix using RPA when address has been resolved

When connecting to a device using an RPA if the address has been
resolved by the controller (types 0x02 and 0x03) the identity address
shall b

Bluetooth: Fix using RPA when address has been resolved

When connecting to a device using an RPA if the address has been
resolved by the controller (types 0x02 and 0x03) the identity address
shall be used as the actual RPA in the advertisement won't be visible
to the host.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

show more ...

Bluetooth: L2CAP: Fix l2cap_global_chan_by_psm

[ Upstream commit f937b758a188d6fd328a81367087eddbb2fce50f ]

l2cap_global_chan_by_psm shall not return fixed channels as they are not
meant to be conn

Bluetooth: L2CAP: Fix l2cap_global_chan_by_psm

[ Upstream commit f937b758a188d6fd328a81367087eddbb2fce50f ]

l2cap_global_chan_by_psm shall not return fixed channels as they are not
meant to be connected by (S)PSM.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Reviewed-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

Bluetooth: L2CAP: Fix attempting to access uninitialized memory

commit b1a2cd50c0357f243b7435a732b4e62ba3157a2e upstream.

On l2cap_parse_conf_req the variable efs is only initialized if
remote_efs

Bluetooth: L2CAP: Fix attempting to access uninitialized memory

commit b1a2cd50c0357f243b7435a732b4e62ba3157a2e upstream.

On l2cap_parse_conf_req the variable efs is only initialized if
remote_efs has been set.

CVE: CVE-2022-42895
CC: stable@vger.kernel.org
Reported-by: Tamás Koczka <poprdi@google.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Reviewed-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

Bluetooth: L2CAP: Fix accepting connection request for invalid SPSM

commit 711f8c3fb3db61897080468586b970c87c61d9e4 upstream.

The Bluetooth spec states that the valid range for SPSM is from
0x0001-

Bluetooth: L2CAP: Fix accepting connection request for invalid SPSM

commit 711f8c3fb3db61897080468586b970c87c61d9e4 upstream.

The Bluetooth spec states that the valid range for SPSM is from
0x0001-0x00ff so it is invalid to accept values outside of this range:

BLUETOOTH CORE SPECIFICATION Version 5.3 | Vol 3, Part A
page 1059:
Table 4.15: L2CAP_LE_CREDIT_BASED_CONNECTION_REQ SPSM ranges

CVE: CVE-2022-42896
CC: stable@vger.kernel.org
Reported-by: Tamás Koczka <poprdi@google.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Reviewed-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

Bluetooth: L2CAP: Fix memory leak in vhci_write

[ Upstream commit 7c9524d929648935bac2bbb4c20437df8f9c3f42 ]

Syzkaller reports a memory leak as follows:
====================================
BUG: me

Bluetooth: L2CAP: Fix memory leak in vhci_write

[ Upstream commit 7c9524d929648935bac2bbb4c20437df8f9c3f42 ]

Syzkaller reports a memory leak as follows:
====================================
BUG: memory leak
unreferenced object 0xffff88810d81ac00 (size 240):
[...]
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff838733d9>] __alloc_skb+0x1f9/0x270 net/core/skbuff.c:418
[<ffffffff833f742f>] alloc_skb include/linux/skbuff.h:1257 [inline]
[<ffffffff833f742f>] bt_skb_alloc include/net/bluetooth/bluetooth.h:469 [inline]
[<ffffffff833f742f>] vhci_get_user drivers/bluetooth/hci_vhci.c:391 [inline]
[<ffffffff833f742f>] vhci_write+0x5f/0x230 drivers/bluetooth/hci_vhci.c:511
[<ffffffff815e398d>] call_write_iter include/linux/fs.h:2192 [inline]
[<ffffffff815e398d>] new_sync_write fs/read_write.c:491 [inline]
[<ffffffff815e398d>] vfs_write+0x42d/0x540 fs/read_write.c:578
[<ffffffff815e3cdd>] ksys_write+0x9d/0x160 fs/read_write.c:631
[<ffffffff845e0645>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff845e0645>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
[<ffffffff84600087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
====================================

HCI core will uses hci_rx_work() to process frame, which is queued to
the hdev->rx_q tail in hci_recv_frame() by HCI driver.

Yet the problem is that, HCI core may not free the skb after handling
ACL data packets. To be more specific, when start fragment does not
contain the L2CAP length, HCI core just copies skb into conn->rx_skb and
finishes frame process in l2cap_recv_acldata(), without freeing the skb,
which triggers the above memory leak.

This patch solves it by releasing the relative skb, after processing
the above case in l2cap_recv_acldata().

Fixes: 4d7ea8ee90e4 ("Bluetooth: L2CAP: Fix handling fragmented length")
Link: https://lore.kernel.org/all/0000000000000d0b1905e6aaef64@google.com/
Reported-and-tested-by: syzbot+8f819e36e01022991cfa@syzkaller.appspotmail.com
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

Bluetooth: L2CAP: fix use-after-free in l2cap_conn_del()

[ Upstream commit 0d0e2d032811280b927650ff3c15fe5020e82533 ]

When l2cap_recv_frame() is invoked to receive data, and the cid is
L2CAP_CID_A2

Bluetooth: L2CAP: fix use-after-free in l2cap_conn_del()

[ Upstream commit 0d0e2d032811280b927650ff3c15fe5020e82533 ]

When l2cap_recv_frame() is invoked to receive data, and the cid is
L2CAP_CID_A2MP, if the channel does not exist, it will create a channel.
However, after a channel is created, the hold operation of the channel
is not performed. In this case, the value of channel reference counting
is 1. As a result, after hci_error_reset() is triggered, l2cap_conn_del()
invokes the close hook function of A2MP to release the channel. Then
l2cap_chan_unlock(chan) will trigger UAF issue.

The process is as follows:
Receive data:
l2cap_data_channel()
a2mp_channel_create() --->channel ref is 2
l2cap_chan_put() --->channel ref is 1

Triger event:
hci_error_reset()
hci_dev_do_close()
...
l2cap_disconn_cfm()
l2cap_conn_del()
l2cap_chan_hold() --->channel ref is 2
l2cap_chan_del() --->channel ref is 1
a2mp_chan_close_cb() --->channel ref is 0, release channel
l2cap_chan_unlock() --->UAF of channel

The detailed Call Trace is as follows:
BUG: KASAN: use-after-free in __mutex_unlock_slowpath+0xa6/0x5e0
Read of size 8 at addr ffff8880160664b8 by task kworker/u11:1/7593
Workqueue: hci0 hci_error_reset
Call Trace:
<TASK>
dump_stack_lvl+0xcd/0x134
print_report.cold+0x2ba/0x719
kasan_report+0xb1/0x1e0
kasan_check_range+0x140/0x190
__mutex_unlock_slowpath+0xa6/0x5e0
l2cap_conn_del+0x404/0x7b0
l2cap_disconn_cfm+0x8c/0xc0
hci_conn_hash_flush+0x11f/0x260
hci_dev_close_sync+0x5f5/0x11f0
hci_dev_do_close+0x2d/0x70
hci_error_reset+0x9e/0x140
process_one_work+0x98a/0x1620
worker_thread+0x665/0x1080
kthread+0x2e4/0x3a0
ret_from_fork+0x1f/0x30
</TASK>

Allocated by task 7593:
kasan_save_stack+0x1e/0x40
__kasan_kmalloc+0xa9/0xd0
l2cap_chan_create+0x40/0x930
amp_mgr_create+0x96/0x990
a2mp_channel_create+0x7d/0x150
l2cap_recv_frame+0x51b8/0x9a70
l2cap_recv_acldata+0xaa3/0xc00
hci_rx_work+0x702/0x1220
process_one_work+0x98a/0x1620
worker_thread+0x665/0x1080
kthread+0x2e4/0x3a0
ret_from_fork+0x1f/0x30

Freed by task 7593:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
kasan_set_free_info+0x20/0x30
____kasan_slab_free+0x167/0x1c0
slab_free_freelist_hook+0x89/0x1c0
kfree+0xe2/0x580
l2cap_chan_put+0x22a/0x2d0
l2cap_conn_del+0x3fc/0x7b0
l2cap_disconn_cfm+0x8c/0xc0
hci_conn_hash_flush+0x11f/0x260
hci_dev_close_sync+0x5f5/0x11f0
hci_dev_do_close+0x2d/0x70
hci_error_reset+0x9e/0x140
process_one_work+0x98a/0x1620
worker_thread+0x665/0x1080
kthread+0x2e4/0x3a0
ret_from_fork+0x1f/0x30

Last potentially related work creation:
kasan_save_stack+0x1e/0x40
__kasan_record_aux_stack+0xbe/0xd0
call_rcu+0x99/0x740
netlink_release+0xe6a/0x1cf0
__sock_release+0xcd/0x280
sock_close+0x18/0x20
__fput+0x27c/0xa90
task_work_run+0xdd/0x1a0
exit_to_user_mode_prepare+0x23c/0x250
syscall_exit_to_user_mode+0x19/0x50
do_syscall_64+0x42/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Second to last potentially related work creation:
kasan_save_stack+0x1e/0x40
__kasan_record_aux_stack+0xbe/0xd0
call_rcu+0x99/0x740
netlink_release+0xe6a/0x1cf0
__sock_release+0xcd/0x280
sock_close+0x18/0x20
__fput+0x27c/0xa90
task_work_run+0xdd/0x1a0
exit_to_user_mode_prepare+0x23c/0x250
syscall_exit_to_user_mode+0x19/0x50
do_syscall_64+0x42/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: d0be8347c623 ("Bluetooth: L2CAP: Fix use-after-free caused by l2cap_chan_put")
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

Bluetooth: L2CAP: Fix use-after-free caused by l2cap_reassemble_sdu

[ Upstream commit 3aff8aaca4e36dc8b17eaa011684881a80238966 ]

Fix the race condition between the following two flows that run in
p

Bluetooth: L2CAP: Fix use-after-free caused by l2cap_reassemble_sdu

[ Upstream commit 3aff8aaca4e36dc8b17eaa011684881a80238966 ]

Fix the race condition between the following two flows that run in
parallel:

1. l2cap_reassemble_sdu -> chan->ops->recv (l2cap_sock_recv_cb) ->
__sock_queue_rcv_skb.

2. bt_sock_recvmsg -> skb_recv_datagram, skb_free_datagram.

An SKB can be queued by the first flow and immediately dequeued and
freed by the second flow, therefore the callers of l2cap_reassemble_sdu
can't use the SKB after that function returns. However, some places
continue accessing struct l2cap_ctrl that resides in the SKB's CB for a
short time after l2cap_reassemble_sdu returns, leading to a
use-after-free condition (the stack trace is below, line numbers for
kernel 5.19.8).

Fix it by keeping a local copy of struct l2cap_ctrl.

BUG: KASAN: use-after-free in l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth
Read of size 1 at addr ffff88812025f2f0 by task kworker/u17:3/43169

Workqueue: hci0 hci_rx_work [bluetooth]
Call Trace:
<TASK>
dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4))
print_report.cold (mm/kasan/report.c:314 mm/kasan/report.c:429)
? l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth
kasan_report (mm/kasan/report.c:162 mm/kasan/report.c:493)
? l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth
l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth
l2cap_rx (net/bluetooth/l2cap_core.c:7236 net/bluetooth/l2cap_core.c:7271) bluetooth
ret_from_fork (arch/x86/entry/entry_64.S:306)
</TASK>

Allocated by task 43169:
kasan_save_stack (mm/kasan/common.c:39)
__kasan_slab_alloc (mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:469)
kmem_cache_alloc_node (mm/slab.h:750 mm/slub.c:3243 mm/slub.c:3293)
__alloc_skb (net/core/skbuff.c:414)
l2cap_recv_frag (./include/net/bluetooth/bluetooth.h:425 net/bluetooth/l2cap_core.c:8329) bluetooth
l2cap_recv_acldata (net/bluetooth/l2cap_core.c:8442) bluetooth
hci_rx_work (net/bluetooth/hci_core.c:3642 net/bluetooth/hci_core.c:3832) bluetooth
process_one_work (kernel/workqueue.c:2289)
worker_thread (./include/linux/list.h:292 kernel/workqueue.c:2437)
kthread (kernel/kthread.c:376)
ret_from_fork (arch/x86/entry/entry_64.S:306)

Freed by task 27920:
kasan_save_stack (mm/kasan/common.c:39)
kasan_set_track (mm/kasan/common.c:45)
kasan_set_free_info (mm/kasan/generic.c:372)
____kasan_slab_free (mm/kasan/common.c:368 mm/kasan/common.c:328)
slab_free_freelist_hook (mm/slub.c:1780)
kmem_cache_free (mm/slub.c:3536 mm/slub.c:3553)
skb_free_datagram (./include/net/sock.h:1578 ./include/net/sock.h:1639 net/core/datagram.c:323)
bt_sock_recvmsg (net/bluetooth/af_bluetooth.c:295) bluetooth
l2cap_sock_recvmsg (net/bluetooth/l2cap_sock.c:1212) bluetooth
sock_read_iter (net/socket.c:1087)
new_sync_read (./include/linux/fs.h:2052 fs/read_write.c:401)
vfs_read (fs/read_write.c:482)
ksys_read (fs/read_write.c:620)
do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)

Link: https://lore.kernel.org/linux-bluetooth/CAKErNvoqga1WcmoR3-0875esY6TVWFQDandbVZncSiuGPBQXLA@mail.gmail.com/T/#u
Fixes: d2a7ac5d5d3a ("Bluetooth: Add the ERTM receive state machine")
Fixes: 4b51dae96731 ("Bluetooth: Add streaming mode receive and incoming packet classifier")
Signed-off-by: Maxim Mikityanskiy <maxtram95@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

Bluetooth: L2CAP: Fix l2cap_global_chan_by_psm

[ Upstream commit f937b758a188d6fd328a81367087eddbb2fce50f ]

l2cap_global_chan_by_psm shall not return fixed channels as they are not
meant to be conn

Bluetooth: L2CAP: Fix l2cap_global_chan_by_psm

[ Upstream commit f937b758a188d6fd328a81367087eddbb2fce50f ]

l2cap_global_chan_by_psm shall not return fixed channels as they are not
meant to be connected by (S)PSM.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Reviewed-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

Bluetooth: L2CAP: Fix attempting to access uninitialized memory

commit b1a2cd50c0357f243b7435a732b4e62ba3157a2e upstream.

On l2cap_parse_conf_req the variable efs is only initialized if
remote_efs

Bluetooth: L2CAP: Fix attempting to access uninitialized memory

commit b1a2cd50c0357f243b7435a732b4e62ba3157a2e upstream.

On l2cap_parse_conf_req the variable efs is only initialized if
remote_efs has been set.

CVE: CVE-2022-42895
CC: stable@vger.kernel.org
Reported-by: Tamás Koczka <poprdi@google.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Reviewed-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

Bluetooth: L2CAP: Fix accepting connection request for invalid SPSM

commit 711f8c3fb3db61897080468586b970c87c61d9e4 upstream.

The Bluetooth spec states that the valid range for SPSM is from
0x0001-

Bluetooth: L2CAP: Fix accepting connection request for invalid SPSM

commit 711f8c3fb3db61897080468586b970c87c61d9e4 upstream.

The Bluetooth spec states that the valid range for SPSM is from
0x0001-0x00ff so it is invalid to accept values outside of this range:

BLUETOOTH CORE SPECIFICATION Version 5.3 | Vol 3, Part A
page 1059:
Table 4.15: L2CAP_LE_CREDIT_BASED_CONNECTION_REQ SPSM ranges

CVE: CVE-2022-42896
CC: stable@vger.kernel.org
Reported-by: Tamás Koczka <poprdi@google.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Reviewed-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

Bluetooth: L2CAP: Fix memory leak in vhci_write

[ Upstream commit 7c9524d929648935bac2bbb4c20437df8f9c3f42 ]

Syzkaller reports a memory leak as follows:
====================================
BUG: me

Bluetooth: L2CAP: Fix memory leak in vhci_write

[ Upstream commit 7c9524d929648935bac2bbb4c20437df8f9c3f42 ]

Syzkaller reports a memory leak as follows:
====================================
BUG: memory leak
unreferenced object 0xffff88810d81ac00 (size 240):
[...]
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff838733d9>] __alloc_skb+0x1f9/0x270 net/core/skbuff.c:418
[<ffffffff833f742f>] alloc_skb include/linux/skbuff.h:1257 [inline]
[<ffffffff833f742f>] bt_skb_alloc include/net/bluetooth/bluetooth.h:469 [inline]
[<ffffffff833f742f>] vhci_get_user drivers/bluetooth/hci_vhci.c:391 [inline]
[<ffffffff833f742f>] vhci_write+0x5f/0x230 drivers/bluetooth/hci_vhci.c:511
[<ffffffff815e398d>] call_write_iter include/linux/fs.h:2192 [inline]
[<ffffffff815e398d>] new_sync_write fs/read_write.c:491 [inline]
[<ffffffff815e398d>] vfs_write+0x42d/0x540 fs/read_write.c:578
[<ffffffff815e3cdd>] ksys_write+0x9d/0x160 fs/read_write.c:631
[<ffffffff845e0645>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff845e0645>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
[<ffffffff84600087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
====================================

HCI core will uses hci_rx_work() to process frame, which is queued to
the hdev->rx_q tail in hci_recv_frame() by HCI driver.

Yet the problem is that, HCI core may not free the skb after handling
ACL data packets. To be more specific, when start fragment does not
contain the L2CAP length, HCI core just copies skb into conn->rx_skb and
finishes frame process in l2cap_recv_acldata(), without freeing the skb,
which triggers the above memory leak.

This patch solves it by releasing the relative skb, after processing
the above case in l2cap_recv_acldata().

Fixes: 4d7ea8ee90e4 ("Bluetooth: L2CAP: Fix handling fragmented length")
Link: https://lore.kernel.org/all/0000000000000d0b1905e6aaef64@google.com/
Reported-and-tested-by: syzbot+8f819e36e01022991cfa@syzkaller.appspotmail.com
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

Bluetooth: L2CAP: fix use-after-free in l2cap_conn_del()

[ Upstream commit 0d0e2d032811280b927650ff3c15fe5020e82533 ]

When l2cap_recv_frame() is invoked to receive data, and the cid is
L2CAP_CID_A2

Bluetooth: L2CAP: fix use-after-free in l2cap_conn_del()

[ Upstream commit 0d0e2d032811280b927650ff3c15fe5020e82533 ]

When l2cap_recv_frame() is invoked to receive data, and the cid is
L2CAP_CID_A2MP, if the channel does not exist, it will create a channel.
However, after a channel is created, the hold operation of the channel
is not performed. In this case, the value of channel reference counting
is 1. As a result, after hci_error_reset() is triggered, l2cap_conn_del()
invokes the close hook function of A2MP to release the channel. Then
l2cap_chan_unlock(chan) will trigger UAF issue.

The process is as follows:
Receive data:
l2cap_data_channel()
a2mp_channel_create() --->channel ref is 2
l2cap_chan_put() --->channel ref is 1

Triger event:
hci_error_reset()
hci_dev_do_close()
...
l2cap_disconn_cfm()
l2cap_conn_del()
l2cap_chan_hold() --->channel ref is 2
l2cap_chan_del() --->channel ref is 1
a2mp_chan_close_cb() --->channel ref is 0, release channel
l2cap_chan_unlock() --->UAF of channel

The detailed Call Trace is as follows:
BUG: KASAN: use-after-free in __mutex_unlock_slowpath+0xa6/0x5e0
Read of size 8 at addr ffff8880160664b8 by task kworker/u11:1/7593
Workqueue: hci0 hci_error_reset
Call Trace:
<TASK>
dump_stack_lvl+0xcd/0x134
print_report.cold+0x2ba/0x719
kasan_report+0xb1/0x1e0
kasan_check_range+0x140/0x190
__mutex_unlock_slowpath+0xa6/0x5e0
l2cap_conn_del+0x404/0x7b0
l2cap_disconn_cfm+0x8c/0xc0
hci_conn_hash_flush+0x11f/0x260
hci_dev_close_sync+0x5f5/0x11f0
hci_dev_do_close+0x2d/0x70
hci_error_reset+0x9e/0x140
process_one_work+0x98a/0x1620
worker_thread+0x665/0x1080
kthread+0x2e4/0x3a0
ret_from_fork+0x1f/0x30
</TASK>

Allocated by task 7593:
kasan_save_stack+0x1e/0x40
__kasan_kmalloc+0xa9/0xd0
l2cap_chan_create+0x40/0x930
amp_mgr_create+0x96/0x990
a2mp_channel_create+0x7d/0x150
l2cap_recv_frame+0x51b8/0x9a70
l2cap_recv_acldata+0xaa3/0xc00
hci_rx_work+0x702/0x1220
process_one_work+0x98a/0x1620
worker_thread+0x665/0x1080
kthread+0x2e4/0x3a0
ret_from_fork+0x1f/0x30

Freed by task 7593:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
kasan_set_free_info+0x20/0x30
____kasan_slab_free+0x167/0x1c0
slab_free_freelist_hook+0x89/0x1c0
kfree+0xe2/0x580
l2cap_chan_put+0x22a/0x2d0
l2cap_conn_del+0x3fc/0x7b0
l2cap_disconn_cfm+0x8c/0xc0
hci_conn_hash_flush+0x11f/0x260
hci_dev_close_sync+0x5f5/0x11f0
hci_dev_do_close+0x2d/0x70
hci_error_reset+0x9e/0x140
process_one_work+0x98a/0x1620
worker_thread+0x665/0x1080
kthread+0x2e4/0x3a0
ret_from_fork+0x1f/0x30

Last potentially related work creation:
kasan_save_stack+0x1e/0x40
__kasan_record_aux_stack+0xbe/0xd0
call_rcu+0x99/0x740
netlink_release+0xe6a/0x1cf0
__sock_release+0xcd/0x280
sock_close+0x18/0x20
__fput+0x27c/0xa90
task_work_run+0xdd/0x1a0
exit_to_user_mode_prepare+0x23c/0x250
syscall_exit_to_user_mode+0x19/0x50
do_syscall_64+0x42/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Second to last potentially related work creation:
kasan_save_stack+0x1e/0x40
__kasan_record_aux_stack+0xbe/0xd0
call_rcu+0x99/0x740
netlink_release+0xe6a/0x1cf0
__sock_release+0xcd/0x280
sock_close+0x18/0x20
__fput+0x27c/0xa90
task_work_run+0xdd/0x1a0
exit_to_user_mode_prepare+0x23c/0x250
syscall_exit_to_user_mode+0x19/0x50
do_syscall_64+0x42/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: d0be8347c623 ("Bluetooth: L2CAP: Fix use-after-free caused by l2cap_chan_put")
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

Bluetooth: L2CAP: Fix use-after-free caused by l2cap_reassemble_sdu

[ Upstream commit 3aff8aaca4e36dc8b17eaa011684881a80238966 ]

Fix the race condition between the following two flows that run in
p

Bluetooth: L2CAP: Fix use-after-free caused by l2cap_reassemble_sdu

[ Upstream commit 3aff8aaca4e36dc8b17eaa011684881a80238966 ]

Fix the race condition between the following two flows that run in
parallel:

1. l2cap_reassemble_sdu -> chan->ops->recv (l2cap_sock_recv_cb) ->
__sock_queue_rcv_skb.

2. bt_sock_recvmsg -> skb_recv_datagram, skb_free_datagram.

An SKB can be queued by the first flow and immediately dequeued and
freed by the second flow, therefore the callers of l2cap_reassemble_sdu
can't use the SKB after that function returns. However, some places
continue accessing struct l2cap_ctrl that resides in the SKB's CB for a
short time after l2cap_reassemble_sdu returns, leading to a
use-after-free condition (the stack trace is below, line numbers for
kernel 5.19.8).

Fix it by keeping a local copy of struct l2cap_ctrl.

BUG: KASAN: use-after-free in l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth
Read of size 1 at addr ffff88812025f2f0 by task kworker/u17:3/43169

Workqueue: hci0 hci_rx_work [bluetooth]
Call Trace:
<TASK>
dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4))
print_report.cold (mm/kasan/report.c:314 mm/kasan/report.c:429)
? l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth
kasan_report (mm/kasan/report.c:162 mm/kasan/report.c:493)
? l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth
l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth
l2cap_rx (net/bluetooth/l2cap_core.c:7236 net/bluetooth/l2cap_core.c:7271) bluetooth
ret_from_fork (arch/x86/entry/entry_64.S:306)
</TASK>

Allocated by task 43169:
kasan_save_stack (mm/kasan/common.c:39)
__kasan_slab_alloc (mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:469)
kmem_cache_alloc_node (mm/slab.h:750 mm/slub.c:3243 mm/slub.c:3293)
__alloc_skb (net/core/skbuff.c:414)
l2cap_recv_frag (./include/net/bluetooth/bluetooth.h:425 net/bluetooth/l2cap_core.c:8329) bluetooth
l2cap_recv_acldata (net/bluetooth/l2cap_core.c:8442) bluetooth
hci_rx_work (net/bluetooth/hci_core.c:3642 net/bluetooth/hci_core.c:3832) bluetooth
process_one_work (kernel/workqueue.c:2289)
worker_thread (./include/linux/list.h:292 kernel/workqueue.c:2437)
kthread (kernel/kthread.c:376)
ret_from_fork (arch/x86/entry/entry_64.S:306)

Freed by task 27920:
kasan_save_stack (mm/kasan/common.c:39)
kasan_set_track (mm/kasan/common.c:45)
kasan_set_free_info (mm/kasan/generic.c:372)
____kasan_slab_free (mm/kasan/common.c:368 mm/kasan/common.c:328)
slab_free_freelist_hook (mm/slub.c:1780)
kmem_cache_free (mm/slub.c:3536 mm/slub.c:3553)
skb_free_datagram (./include/net/sock.h:1578 ./include/net/sock.h:1639 net/core/datagram.c:323)
bt_sock_recvmsg (net/bluetooth/af_bluetooth.c:295) bluetooth
l2cap_sock_recvmsg (net/bluetooth/l2cap_sock.c:1212) bluetooth
sock_read_iter (net/socket.c:1087)
new_sync_read (./include/linux/fs.h:2052 fs/read_write.c:401)
vfs_read (fs/read_write.c:482)
ksys_read (fs/read_write.c:620)
do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)

Link: https://lore.kernel.org/linux-bluetooth/CAKErNvoqga1WcmoR3-0875esY6TVWFQDandbVZncSiuGPBQXLA@mail.gmail.com/T/#u
Fixes: d2a7ac5d5d3a ("Bluetooth: Add the ERTM receive state machine")
Fixes: 4b51dae96731 ("Bluetooth: Add streaming mode receive and incoming packet classifier")
Signed-off-by: Maxim Mikityanskiy <maxtram95@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

Bluetooth: L2CAP: Fix l2cap_global_chan_by_psm

[ Upstream commit f937b758a188d6fd328a81367087eddbb2fce50f ]

l2cap_global_chan_by_psm shall not return fixed channels as they are not
meant to be conn

Bluetooth: L2CAP: Fix l2cap_global_chan_by_psm

[ Upstream commit f937b758a188d6fd328a81367087eddbb2fce50f ]

l2cap_global_chan_by_psm shall not return fixed channels as they are not
meant to be connected by (S)PSM.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Reviewed-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

Bluetooth: L2CAP: Fix attempting to access uninitialized memory

commit b1a2cd50c0357f243b7435a732b4e62ba3157a2e upstream.

On l2cap_parse_conf_req the variable efs is only initialized if
remote_efs

Bluetooth: L2CAP: Fix attempting to access uninitialized memory

commit b1a2cd50c0357f243b7435a732b4e62ba3157a2e upstream.

On l2cap_parse_conf_req the variable efs is only initialized if
remote_efs has been set.

CVE: CVE-2022-42895
CC: stable@vger.kernel.org
Reported-by: Tamás Koczka <poprdi@google.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Reviewed-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

Bluetooth: L2CAP: Fix accepting connection request for invalid SPSM

commit 711f8c3fb3db61897080468586b970c87c61d9e4 upstream.

The Bluetooth spec states that the valid range for SPSM is from
0x0001-

Bluetooth: L2CAP: Fix accepting connection request for invalid SPSM

commit 711f8c3fb3db61897080468586b970c87c61d9e4 upstream.

The Bluetooth spec states that the valid range for SPSM is from
0x0001-0x00ff so it is invalid to accept values outside of this range:

BLUETOOTH CORE SPECIFICATION Version 5.3 | Vol 3, Part A
page 1059:
Table 4.15: L2CAP_LE_CREDIT_BASED_CONNECTION_REQ SPSM ranges

CVE: CVE-2022-42896
CC: stable@vger.kernel.org
Reported-by: Tamás Koczka <poprdi@google.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Reviewed-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

Bluetooth: L2CAP: Fix memory leak in vhci_write

[ Upstream commit 7c9524d929648935bac2bbb4c20437df8f9c3f42 ]

Syzkaller reports a memory leak as follows:
====================================
BUG: me

Bluetooth: L2CAP: Fix memory leak in vhci_write

[ Upstream commit 7c9524d929648935bac2bbb4c20437df8f9c3f42 ]

Syzkaller reports a memory leak as follows:
====================================
BUG: memory leak
unreferenced object 0xffff88810d81ac00 (size 240):
[...]
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff838733d9>] __alloc_skb+0x1f9/0x270 net/core/skbuff.c:418
[<ffffffff833f742f>] alloc_skb include/linux/skbuff.h:1257 [inline]
[<ffffffff833f742f>] bt_skb_alloc include/net/bluetooth/bluetooth.h:469 [inline]
[<ffffffff833f742f>] vhci_get_user drivers/bluetooth/hci_vhci.c:391 [inline]
[<ffffffff833f742f>] vhci_write+0x5f/0x230 drivers/bluetooth/hci_vhci.c:511
[<ffffffff815e398d>] call_write_iter include/linux/fs.h:2192 [inline]
[<ffffffff815e398d>] new_sync_write fs/read_write.c:491 [inline]
[<ffffffff815e398d>] vfs_write+0x42d/0x540 fs/read_write.c:578
[<ffffffff815e3cdd>] ksys_write+0x9d/0x160 fs/read_write.c:631
[<ffffffff845e0645>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff845e0645>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
[<ffffffff84600087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
====================================

HCI core will uses hci_rx_work() to process frame, which is queued to
the hdev->rx_q tail in hci_recv_frame() by HCI driver.

Yet the problem is that, HCI core may not free the skb after handling
ACL data packets. To be more specific, when start fragment does not
contain the L2CAP length, HCI core just copies skb into conn->rx_skb and
finishes frame process in l2cap_recv_acldata(), without freeing the skb,
which triggers the above memory leak.

This patch solves it by releasing the relative skb, after processing
the above case in l2cap_recv_acldata().

Fixes: 4d7ea8ee90e4 ("Bluetooth: L2CAP: Fix handling fragmented length")
Link: https://lore.kernel.org/all/0000000000000d0b1905e6aaef64@google.com/
Reported-and-tested-by: syzbot+8f819e36e01022991cfa@syzkaller.appspotmail.com
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

show more ...

Bluetooth: L2CAP: fix use-after-free in l2cap_conn_del()

[ Upstream commit 0d0e2d032811280b927650ff3c15fe5020e82533 ]

When l2cap_recv_frame() is invoked to receive data, and the cid is
L2CAP_CID_A2

Bluetooth: L2CAP: fix use-after-free in l2cap_conn_del()

[ Upstream commit 0d0e2d032811280b927650ff3c15fe5020e82533 ]

When l2cap_recv_frame() is invoked to receive data, and the cid is
L2CAP_CID_A2MP, if the channel does not exist, it will create a channel.
However, after a channel is created, the hold operation of the channel
is not performed. In this case, the value of channel reference counting
is 1. As a result, after hci_error_reset() is triggered, l2cap_conn_del()
invokes the close hook function of A2MP to release the channel. Then
l2cap_chan_unlock(chan) will trigger UAF issue.

The process is as follows:
Receive data:
l2cap_data_channel()
a2mp_channel_create() --->channel ref is 2
l2cap_chan_put() --->channel ref is 1

Triger event:
hci_error_reset()
hci_dev_do_close()
...
l2cap_disconn_cfm()
l2cap_conn_del()
l2cap_chan_hold() --->channel ref is 2
l2cap_chan_del() --->channel ref is 1
a2mp_chan_close_cb() --->channel ref is 0, release channel
l2cap_chan_unlock() --->UAF of channel

The detailed Call Trace is as follows:
BUG: KASAN: use-after-free in __mutex_unlock_slowpath+0xa6/0x5e0
Read of size 8 at addr ffff8880160664b8 by task kworker/u11:1/7593
Workqueue: hci0 hci_error_reset
Call Trace:
<TASK>
dump_stack_lvl+0xcd/0x134
print_report.cold+0x2ba/0x719
kasan_report+0xb1/0x1e0
kasan_check_range+0x140/0x190
__mutex_unlock_slowpath+0xa6/0x5e0
l2cap_conn_del+0x404/0x7b0
l2cap_disconn_cfm+0x8c/0xc0
hci_conn_hash_flush+0x11f/0x260
hci_dev_close_sync+0x5f5/0x11f0
hci_dev_do_close+0x2d/0x70
hci_error_reset+0x9e/0x140
process_one_work+0x98a/0x1620
worker_thread+0x665/0x1080
kthread+0x2e4/0x3a0
ret_from_fork+0x1f/0x30
</TASK>

Allocated by task 7593:
kasan_save_stack+0x1e/0x40
__kasan_kmalloc+0xa9/0xd0
l2cap_chan_create+0x40/0x930
amp_mgr_create+0x96/0x990
a2mp_channel_create+0x7d/0x150
l2cap_recv_frame+0x51b8/0x9a70
l2cap_recv_acldata+0xaa3/0xc00
hci_rx_work+0x702/0x1220
process_one_work+0x98a/0x1620
worker_thread+0x665/0x1080
kthread+0x2e4/0x3a0
ret_from_fork+0x1f/0x30

Freed by task 7593:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
kasan_set_free_info+0x20/0x30
____kasan_slab_free+0x167/0x1c0
slab_free_freelist_hook+0x89/0x1c0
kfree+0xe2/0x580
l2cap_chan_put+0x22a/0x2d0
l2cap_conn_del+0x3fc/0x7b0
l2cap_disconn_cfm+0x8c/0xc0
hci_conn_hash_flush+0x11f/0x260
hci_dev_close_sync+0x5f5/0x11f0
hci_dev_do_close+0x2d/0x70
hci_error_reset+0x9e/0x140
process_one_work+0x98a/0x1620
worker_thread+0x665/0x1080
kthread+0x2e4/0x3a0
ret_from_fork+0x1f/0x30

Last potentially related work creation:
kasan_save_stack+0x1e/0x40
__kasan_record_aux_stack+0xbe/0xd0
call_rcu+0x99/0x740
netlink_release+0xe6a/0x1cf0
__sock_release+0xcd/0x280
sock_close+0x18/0x20
__fput+0x27c/0xa90
task_work_run+0xdd/0x1a0
exit_to_user_mode_prepare+0x23c/0x250
syscall_exit_to_user_mode+0x19/0x50
do_syscall_64+0x42/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Second to last potentially related work creation:
kasan_save_stack+0x1e/0x40
__kasan_record_aux_stack+0xbe/0xd0
call_rcu+0x99/0x740
netlink_release+0xe6a/0x1cf0
__sock_release+0xcd/0x280
sock_close+0x18/0x20
__fput+0x27c/0xa90
task_work_run+0xdd/0x1a0
exit_to_user_mode_prepare+0x23c/0x250
syscall_exit_to_user_mode+0x19/0x50
do_syscall_64+0x42/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: d0be8347c623 ("Bluetooth: L2CAP: Fix use-after-free caused by l2cap_chan_put")
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Bluetooth: L2CAP: Fix use-after-free caused by l2cap_reassemble_sdu

[ Upstream commit 3aff8aaca4e36dc8b17eaa011684881a80238966 ]

Fix the race condition between the following two flows that run in
p

Bluetooth: L2CAP: Fix use-after-free caused by l2cap_reassemble_sdu

[ Upstream commit 3aff8aaca4e36dc8b17eaa011684881a80238966 ]

Fix the race condition between the following two flows that run in
parallel:

1. l2cap_reassemble_sdu -> chan->ops->recv (l2cap_sock_recv_cb) ->
__sock_queue_rcv_skb.

2. bt_sock_recvmsg -> skb_recv_datagram, skb_free_datagram.

An SKB can be queued by the first flow and immediately dequeued and
freed by the second flow, therefore the callers of l2cap_reassemble_sdu
can't use the SKB after that function returns. However, some places
continue accessing struct l2cap_ctrl that resides in the SKB's CB for a
short time after l2cap_reassemble_sdu returns, leading to a
use-after-free condition (the stack trace is below, line numbers for
kernel 5.19.8).

Fix it by keeping a local copy of struct l2cap_ctrl.

BUG: KASAN: use-after-free in l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth
Read of size 1 at addr ffff88812025f2f0 by task kworker/u17:3/43169

Workqueue: hci0 hci_rx_work [bluetooth]
Call Trace:
<TASK>
dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4))
print_report.cold (mm/kasan/report.c:314 mm/kasan/report.c:429)
? l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth
kasan_report (mm/kasan/report.c:162 mm/kasan/report.c:493)
? l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth
l2cap_rx_state_recv (net/bluetooth/l2cap_core.c:6906) bluetooth
l2cap_rx (net/bluetooth/l2cap_core.c:7236 net/bluetooth/l2cap_core.c:7271) bluetooth
ret_from_fork (arch/x86/entry/entry_64.S:306)
</TASK>

Allocated by task 43169:
kasan_save_stack (mm/kasan/common.c:39)
__kasan_slab_alloc (mm/kasan/common.c:45 mm/kasan/common.c:436 mm/kasan/common.c:469)
kmem_cache_alloc_node (mm/slab.h:750 mm/slub.c:3243 mm/slub.c:3293)
__alloc_skb (net/core/skbuff.c:414)
l2cap_recv_frag (./include/net/bluetooth/bluetooth.h:425 net/bluetooth/l2cap_core.c:8329) bluetooth
l2cap_recv_acldata (net/bluetooth/l2cap_core.c:8442) bluetooth
hci_rx_work (net/bluetooth/hci_core.c:3642 net/bluetooth/hci_core.c:3832) bluetooth
process_one_work (kernel/workqueue.c:2289)
worker_thread (./include/linux/list.h:292 kernel/workqueue.c:2437)
kthread (kernel/kthread.c:376)
ret_from_fork (arch/x86/entry/entry_64.S:306)

Freed by task 27920:
kasan_save_stack (mm/kasan/common.c:39)
kasan_set_track (mm/kasan/common.c:45)
kasan_set_free_info (mm/kasan/generic.c:372)
____kasan_slab_free (mm/kasan/common.c:368 mm/kasan/common.c:328)
slab_free_freelist_hook (mm/slub.c:1780)
kmem_cache_free (mm/slub.c:3536 mm/slub.c:3553)
skb_free_datagram (./include/net/sock.h:1578 ./include/net/sock.h:1639 net/core/datagram.c:323)
bt_sock_recvmsg (net/bluetooth/af_bluetooth.c:295) bluetooth
l2cap_sock_recvmsg (net/bluetooth/l2cap_sock.c:1212) bluetooth
sock_read_iter (net/socket.c:1087)
new_sync_read (./include/linux/fs.h:2052 fs/read_write.c:401)
vfs_read (fs/read_write.c:482)
ksys_read (fs/read_write.c:620)
do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120)

Link: https://lore.kernel.org/linux-bluetooth/CAKErNvoqga1WcmoR3-0875esY6TVWFQDandbVZncSiuGPBQXLA@mail.gmail.com/T/#u
Fixes: d2a7ac5d5d3a ("Bluetooth: Add the ERTM receive state machine")
Fixes: 4b51dae96731 ("Bluetooth: Add streaming mode receive and incoming packet classifier")
Signed-off-by: Maxim Mikityanskiy <maxtram95@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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