linux/net/bluetooth
Chengfeng Ye e32d80293a Bluetooth: ISO: Serialize concurrent connect calls
iso_sock_connect() checks the socket state before taking the socket lock
and drops the lock again before setting up a connection. Two callers can
both pass the admission check while the socket is open or bound.

Caller A can copy its destination for route selection, then caller B can
replace the socket destination before A binds or connects the CIS. A
then uses B's destination with the route selected for its own request.
B can also proceed after A attaches a connection and sets BT_CONNECT.
For deferred BIS setup, B can bind a second BIS and overwrite
iso_pi(sk)->conn, leaving the first connection's reference and conn->sk
back-pointer stranded. Concurrent CIS connects can likewise replace the
socket's connection. Later teardown only detaches the current connection,
so a callback on the old connection can race with socket release and
access a freed socket.

KASAN reported:

  BUG: KASAN: slab-use-after-free in iso_sock_hold+0xf7/0x1b0
  Call Trace:
   iso_sock_hold+0xf7/0x1b0
   iso_conn_del+0x7b/0x1d0
   iso_connect_cfm+0x186/0x16a0
   hci_conn_failed+0x154/0x280
   hci_abort_conn_sync+0x3dc/0x7d0
   hci_cmd_sync_work+0x173/0x300

  Allocated by task 121:
   sk_alloc+0x2b/0x6d0
   bt_sock_alloc+0x29/0x370
   iso_sock_alloc.constprop.0+0x19/0x300
   iso_sock_create+0x94/0x100

  Freed by task 121:
   kfree+0x121/0x3c0
   __sk_destruct+0x42b/0x540
   iso_sock_release+0x29d/0x340
   __sock_release+0xa1/0x260

Check admission under the socket lock and mark the connect operation in
progress before publishing its destination. Keep that flag set across
route lookup and connection setup, rejecting another connect with
-EBADFD before it can change the destination or attach a connection.
Clear the flag after either helper returns, including on failure, so a
failed setup can be retried.

A separate flag is needed because the socket lock must be released before
acquiring the HCI device lock, while BT_CONNECT requires an attached
connection. Keep the existing state transitions and the deferred CIS
completion through iso_sock_recvmsg().

Reject an existing socket attachment in __iso_chan_add() before taking
a new reference or publishing either pointer, so every caller preserves
the connection association. Keep the same-socket, same-connection success
case for deferred CIS setup. Reject an attached socket before BIS setup
so a reusable BIS is not claimed before the attachment is rejected.

In CIS setup, reject a different HCI connection before iso_conn_add()
and drop the per-attempt HCI hold directly. An unowned iso_conn may still
carry another reference after detachment, so its destruction cannot be
relied on to release that hold.

iso_listen_bis() creates a fresh PA HCI/ISO pair under the device lock,
so the temporary iso_conn_put() frees the ISO candidate and drops its
HCI hold on rejection. iso_conn_ready() uses a freshly allocated,
unpublished child with no connection, making the socket-side rejection
unreachable.

Fixes: ccf74f2390 ("Bluetooth: Add BTPROTO_ISO socket type")
Cc: stable@vger.kernel.org
Suggested-by: Pauli Virtanen <pav@iki.fi>
Assisted-by: GPT-6 Astra
Signed-off-by: Chengfeng Ye <nicoyip.dev@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
2026-10-05 13:10:47 -04:00
..
bnep Bluetooth: bnep: fix out-of-bounds reads on short RX/TX frames and control fallthrough 2026-09-21 09:37:19 -04:00
hidp Bluetooth: fix BT dependency for submodules 2026-08-07 15:38:30 -04:00
rfcomm Bluetooth: RFCOMM: Fix NULL tty_dev dereference in rfcomm_dev_shutdown 2026-10-02 11:25:53 -04:00
6lowpan.c Bluetooth: add annotations for l2cap_data locking context 2026-08-07 15:38:32 -04:00
af_bluetooth.c Bluetooth: af_bluetooth: Add minimal context analysis annotations 2026-08-07 12:26:02 -04:00
aosp.c Bluetooth: aosp: Fix typo in comment 2025-07-23 10:30:18 -04:00
aosp.h Bluetooth: aosp: Support AOSP Bluetooth Quality Report 2021-11-02 19:37:52 +01:00
coredump.c Bluetooth: coredump: Quiesce dump work on unregister 2026-09-15 14:49:41 -04:00
ecdh_helper.c Bluetooth: Add SPDX id lines to some source files 2026-06-11 14:24:41 -04:00
ecdh_helper.h Bluetooth: Add SPDX id lines to some source files 2026-06-11 14:24:41 -04:00
eir.c Bluetooth: eir: validate service data length before reading UUID 2026-09-15 14:30:14 -04:00
eir.h Bluetooth: eir: Fix possible crashes on eir_create_adv_data 2025-06-11 16:29:22 -04:00
hci_codec.c Bluetooth: hci_codec: validate vendor codec count length 2026-09-15 14:52:12 -04:00
hci_codec.h
hci_conn.c Bluetooth: hci_conn: Lock parent access during enhanced SCO setup 2026-09-28 11:00:20 -04:00
hci_core.c Bluetooth: hci_sync: Fix command skb lifetime during scan setup 2026-10-05 13:10:46 -04:00
hci_debugfs.c Bluetooth: hci_core: Fix inquiry cache timestamps on 64-bit systems 2026-09-23 09:30:21 -04:00
hci_debugfs.h Bluetooth: Add SPDX id lines to some source files 2026-06-11 14:24:41 -04:00
hci_drv.c Bluetooth: Introduce HCI Driver protocol 2025-05-21 10:28:07 -04:00
hci_event.c Bluetooth: hci_event: clear HCI_LE_ADV only on a created connection 2026-08-24 13:11:42 -04:00
hci_sock.c Bluetooth: hci_sock: Serialize dead-device detachment 2026-10-05 13:10:46 -04:00
hci_sync.c Bluetooth: hci_sync: Fix command skb lifetime during scan setup 2026-10-05 13:10:46 -04:00
hci_sysfs.c Bluetooth: hci_sysfs: Fix NULL pointer dereference in device_del() 2026-09-08 17:12:45 -04:00
iso.c Bluetooth: ISO: Serialize concurrent connect calls 2026-10-05 13:10:47 -04:00
Kconfig Bluetooth: fix BT dependency for submodules 2026-08-07 15:38:30 -04:00
l2cap_core.c Bluetooth: L2CAP: validate frame length before control and FCS access 2026-09-16 13:51:34 -04:00
l2cap_sock.c Bluetooth: L2CAP: fix race l2cap_sock_cleanup_listen() vs. put_chan 2026-08-24 13:06:49 -04:00
leds.c Bluetooth: Use led_set_brightness() in LED trigger activate() callback 2024-09-10 13:06:11 -04:00
leds.h
lib.c Bluetooth: Add SPDX id lines to some source files 2026-06-11 14:24:41 -04:00
Makefile Bluetooth: enable context analysis 2026-08-07 12:27:20 -04:00
mgmt_config.c Bluetooth: mgmt: Add idle_timeout to configurable system parameters 2026-01-29 13:24:22 -05:00
mgmt_config.h
mgmt_util.c Bluetooth: Add SPDX id lines to some source files 2026-06-11 14:24:41 -04:00
mgmt_util.h Bluetooth: Add SPDX id lines to some source files 2026-06-11 14:24:41 -04:00
mgmt.c Bluetooth: MGMT: Fix status of pending commands flushed on power off 2026-09-29 11:20:25 -04:00
msft.c Bluetooth: hci_core: Fix race condition during device registration 2026-08-31 13:52:54 -04:00
msft.h Bluetooth: msft: fix slab-use-after-free in msft_do_close() 2024-05-03 13:05:28 -04:00
sco.c Bluetooth: SCO: serialise sco_conn lifetime against sco_recv_scodata() 2026-09-28 13:03:49 -04:00
selftest.c Bluetooth: Add SPDX id lines to some source files 2026-06-11 14:24:41 -04:00
selftest.h Bluetooth: Add SPDX id lines to some source files 2026-06-11 14:24:41 -04:00
smp.c Bluetooth: Serialize SMP remote OOB data access 2026-09-28 11:00:20 -04:00
smp.h Bluetooth: add annotations for l2cap_data locking context 2026-08-07 15:38:32 -04:00