linux-toradex.git/net/bluetooth/l2cap_core.c, branch v6.4

Bluetooth: L2CAP: Add missing checks for invalid DCID

2023-06-06T00:24:14+00:00

When receiving a connect response we should make sure that the DCID is
within the valid range and that we don't already have another channel
allocated for the same DCID.
Missing checks may violate the specification (BLUETOOTH CORE SPECIFICATION
Version 5.4 | Vol 3, Part A, Page 1046).

Fixes: 40624183c202 ("Bluetooth: L2CAP: Add missing checks for invalid LE DCID")
Signed-off-by: Sungwoo Kim 
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: Fix l2cap_disconnect_req deadlock

2023-06-06T00:13:14+00:00

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 
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: L2CAP: fix "bad unlock balance" in l2cap_disconnect_rsp

2023-04-24T05:05:23+00:00

conn->chan_lock isn't acquired before l2cap_get_chan_by_scid,
if l2cap_get_chan_by_scid returns NULL, then 'bad unlock balance'
is triggered.

Reported-by: syzbot+9519d6b5b79cf7787cf3@syzkaller.appspotmail.com
Link: https://lore.kernel.org/all/000000000000894f5f05f95e9f4d@google.com/
Signed-off-by: Min Li 
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: L2CAP: Delay identity address updates

2023-04-24T04:48:44+00:00

This delays the identity address updates to give time for userspace to
process the new address otherwise there is a risk that userspace
creates a duplicated device if the MGMT event is delayed for some
reason.

Signed-off-by: Luiz Augusto von Dentz

Bluetooth: L2CAP: Fix use-after-free in l2cap_disconnect_{req,rsp}

2023-04-10T17:24:32+00:00

Similar to commit d0be8347c623 ("Bluetooth: L2CAP: Fix use-after-free
caused by l2cap_chan_put"), just use l2cap_chan_hold_unless_zero to
prevent referencing a channel that is about to be destroyed.

Cc: stable@kernel.org
Signed-off-by: Luiz Augusto von Dentz 
Signed-off-by: Min Li

Bluetooth: L2CAP: Fix responding with wrong PDU type

2023-03-23T20:09:38+00:00

L2CAP_ECRED_CONN_REQ shall be responded with L2CAP_ECRED_CONN_RSP not
L2CAP_LE_CONN_RSP:

L2CAP LE EATT Server - Reject - run
  Listening for connections
  New client connection with handle 0x002a
  Sending L2CAP Request from client
  Client received response code 0x15
  Unexpected L2CAP response code (expected 0x18)
L2CAP LE EATT Server - Reject - test failed

> ACL Data RX: Handle 42 flags 0x02 dlen 26
      LE L2CAP: Enhanced Credit Connection Request (0x17) ident 1 len 18
        PSM: 39 (0x0027)
        MTU: 64
        MPS: 64
        Credits: 5
        Source CID: 65
        Source CID: 66
        Source CID: 67
        Source CID: 68
        Source CID: 69
< ACL Data TX: Handle 42 flags 0x00 dlen 16
      LE L2CAP: LE Connection Response (0x15) ident 1 len 8
        invalid size
        00 00 00 00 00 00 06 00

L2CAP LE EATT Server - Reject - run
  Listening for connections
  New client connection with handle 0x002a
  Sending L2CAP Request from client
  Client received response code 0x18
L2CAP LE EATT Server - Reject - test passed

Fixes: 15f02b910562 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode")
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: L2CAP: Fix potential user-after-free

2023-02-09T22:18:48+00:00

This fixes all instances of which requires to allocate a buffer calling
alloc_skb which may release the chan lock and reacquire later which
makes it possible that the chan is disconnected in the meantime.

Fixes: a6a5568c03c4 ("Bluetooth: Lock the L2CAP channel when sending")
Reported-by: Alexander Coffin 
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: Add CONFIG_BT_LE_L2CAP_ECRED

2022-12-12T22:19:24+00:00

This adds CONFIG_BT_LE_L2CAP_ECRED which can be used to enable L2CAP
Enhanced Credit Flow Control Mode by default, previously it was only
possible to set it via module parameter (e.g. bluetooth.enable_ecred=1).

Since L2CAP ECRED mode is required by the likes of EATT which is
recommended for LE Audio this enables it by default.

Signed-off-by: Luiz Augusto von Dentz 
Tested-By: Tedd Ho-Jeong An

Bluetooth: L2CAP: Fix u8 overflow

2022-12-02T21:09:30+00:00

By keep sending L2CAP_CONF_REQ packets, chan->num_conf_rsp increases
multiple times and eventually it will wrap around the maximum number
(i.e., 255).
This patch prevents this by adding a boundary check with
L2CAP_MAX_CONF_RSP

Btmon log:
Bluetooth monitor ver 5.64
= Note: Linux version 6.1.0-rc2 (x86_64)                               0.264594
= Note: Bluetooth subsystem version 2.22                               0.264636
@ MGMT Open: btmon (privileged) version 1.22                  {0x0001} 0.272191
= New Index: 00:00:00:00:00:00 (Primary,Virtual,hci0)          [hci0] 13.877604
@ RAW Open: 9496 (privileged) version 2.22                   {0x0002} 13.890741
= Open Index: 00:00:00:00:00:00                                [hci0] 13.900426
(...)
> ACL Data RX: Handle 200 flags 0x00 dlen 1033             #32 [hci0] 14.273106
        invalid packet size (12 != 1033)
        08 00 01 00 02 01 04 00 01 10 ff ff              ............
> ACL Data RX: Handle 200 flags 0x00 dlen 1547             #33 [hci0] 14.273561
        invalid packet size (14 != 1547)
        0a 00 01 00 04 01 06 00 40 00 00 00 00 00        ........@.....
> ACL Data RX: Handle 200 flags 0x00 dlen 2061             #34 [hci0] 14.274390
        invalid packet size (16 != 2061)
        0c 00 01 00 04 01 08 00 40 00 00 00 00 00 00 04  ........@.......
> ACL Data RX: Handle 200 flags 0x00 dlen 2061             #35 [hci0] 14.274932
        invalid packet size (16 != 2061)
        0c 00 01 00 04 01 08 00 40 00 00 00 07 00 03 00  ........@.......
= bluetoothd: Bluetooth daemon 5.43                                   14.401828
> ACL Data RX: Handle 200 flags 0x00 dlen 1033             #36 [hci0] 14.275753
        invalid packet size (12 != 1033)
        08 00 01 00 04 01 04 00 40 00 00 00              ........@...

Signed-off-by: Sungwoo Kim 
Signed-off-by: Luiz Augusto von Dentz

Bluetooth: L2CAP: Fix attempting to access uninitialized memory

2022-11-02T23:37:00+00:00

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 
Signed-off-by: Luiz Augusto von Dentz 
Reviewed-by: Tedd Ho-Jeong An