kernel/git/next/linux-next.git/net/bluetooth/sco.c, branch stable

Bluetooth: sco: Fix a race condition in sco_sock_timeout()

2026-07-06T14:46:57+00:00

sco_sock_timeout() runs asynchronously and lock_sock(sk). If the socket is closing while the timer is running, it holds the same lock (lock_sock(sk)) twice, leading to a deadlock. CPU 0 CPU 1 ==================== ====================== sco_sock_close() sco_sock_timeout() lock_sock(sk) // <-- LOCK __sco_sock_close() sco_chan_del() sco_conn_put() sco_conn_free() disable_delayed_work_sync() lock(sk) // <-- SAME LOCK Fix this by moving disable_delayed_work_sync() outside of lock_sock(sk), ensuring that no lock_sock(sk) is held before sco_sock_timeout(). Lockdep splat: WARNING: possible circular locking dependency detected 6.13.0-rc4 #7 Not tainted syz-executor292/9514 is trying to acquire lock: ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire sect/v6.13-rc4/./include/linux/rcupdate.h:337 [inline] ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: rcu_read_lock sect/v6.13-rc4/./include/linux/rcupdate.h:849 [inline] ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: start_flush_work sect/v6.13-rc4/kernel/workqueue.c:4137 [inline] ffff8881115d5070 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}, at: __flush_work+0xd1/0xc40 sect/v6.13-rc4/kernel/workqueue.c:4195 but task is already holding lock: ffff88807db3a258 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sock sect/v6.13-rc4/./include/net/sock.h:1623 [inline] ffff88807db3a258 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_sock_close+0x25/0x100 sect/v6.13-rc4/net/bluetooth/sco.c:524 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}: lock_acquire+0x1c4/0x520 sect/v6.13-rc4/kernel/locking/lockdep.c:5849 lock_sock_nested+0x48/0x130 sect/v6.13-rc4/net/core/sock.c:3622 lock_sock sect/v6.13-rc4/./include/net/sock.h:1623 [inline] sco_sock_timeout+0xbe/0x270 sect/v6.13-rc4/net/bluetooth/sco.c:158 process_one_work sect/v6.13-rc4/kernel/workqueue.c:3229 [inline] process_scheduled_works+0xa99/0x18f0 sect/v6.13-rc4/kernel/workqueue.c:3310 worker_thread+0x8a9/0xd80 sect/v6.13-rc4/kernel/workqueue.c:3391 kthread+0x2c6/0x360 sect/v6.13-rc4/kernel/kthread.c:389 ret_from_fork+0x4e/0x80 sect/v6.13-rc4/arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 sect/v6.13-rc4/arch/x86/entry/entry_64.S:244 -> #0 ((work_completion)(&(&conn->timeout_work)->work)){+.+.}-{0:0}: check_prev_add sect/v6.13-rc4/kernel/locking/lockdep.c:3161 [inline] check_prevs_add sect/v6.13-rc4/kernel/locking/lockdep.c:3280 [inline] validate_chain+0x1888/0x5760 sect/v6.13-rc4/kernel/locking/lockdep.c:3904 __lock_acquire+0x13b4/0x2120 sect/v6.13-rc4/kernel/locking/lockdep.c:5226 lock_acquire+0x1c4/0x520 sect/v6.13-rc4/kernel/locking/lockdep.c:5849 touch_work_lockdep_map sect/v6.13-rc4/kernel/workqueue.c:3909 [inline] start_flush_work sect/v6.13-rc4/kernel/workqueue.c:4163 [inline] __flush_work+0x70f/0xc40 sect/v6.13-rc4/kernel/workqueue.c:4195 __cancel_work_sync sect/v6.13-rc4/kernel/workqueue.c:4351 [inline] disable_delayed_work_sync+0xbb/0xf0 sect/v6.13-rc4/kernel/workqueue.c:4514 sco_conn_free sect/v6.13-rc4/net/bluetooth/sco.c:95 [inline] kref_put sect/v6.13-rc4/./include/linux/kref.h:65 [inline] sco_conn_put+0x18f/0x270 sect/v6.13-rc4/net/bluetooth/sco.c:107 sco_chan_del+0xe2/0x210 sect/v6.13-rc4/net/bluetooth/sco.c:236 sco_sock_close+0x8f/0x100 sect/v6.13-rc4/net/bluetooth/sco.c:526 sco_sock_release+0x62/0x2d0 sect/v6.13-rc4/net/bluetooth/sco.c:1300 __sock_release+0xe1/0x2d0 sect/v6.13-rc4/net/socket.c:640 sock_close+0x1c/0x30 sect/v6.13-rc4/net/socket.c:1408 __fput+0x2bd/0xa80 sect/v6.13-rc4/fs/file_table.c:450 __fput_sync+0x15e/0x1c0 sect/v6.13-rc4/fs/file_table.c:535 __do_sys_close sect/v6.13-rc4/fs/open.c:1554 [inline] __se_sys_close sect/v6.13-rc4/fs/open.c:1539 [inline] __x64_sys_close+0x93/0x120 sect/v6.13-rc4/fs/open.c:1539 do_syscall_x64 sect/v6.13-rc4/arch/x86/entry/common.c:52 [inline] do_syscall_64+0xee/0x210 sect/v6.13-rc4/arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: e6720779ae61 ("Bluetooth: SCO: Use kref to track lifetime of sco_conn") Acked-by: Dave Tian Signed-off-by: Sungwoo Kim Signed-off-by: Luiz Augusto von Dentz

Bluetooth: Add SPDX id lines to some source files

2026-06-11T18:24:41+00:00

Many bluetooth source files are missing SPDX-License-Identifier lines. Add appropriate IDs to these files, and remove other license lines from the headers. Leave the warranty disclaimer in files where the license ID is GPL-2.0 but the wording of the disclaimer is slightly different from that of the GPL v2 disclaimer. It is not different enough to cause licensing conflicts, but is kept to honor the original contributors' legal intent. Signed-off-by: Tim Bird Signed-off-by: Luiz Augusto von Dentz

Bluetooth: SCO: convert to getsockopt_iter

2026-06-11T18:24:39+00:00

Convert SCO socket's getsockopt implementation to use the new getsockopt_iter callback with sockopt_t. Key changes: - Replace (char __user *optval, int __user *optlen) with sockopt_t *opt - Use opt->optlen for buffer length (input) and returned size (output) - Use copy_to_iter() instead of put_user()/copy_to_user() - Drop the open-coded ptr cursor in BT_CODEC; iter_out advances on every copy_to_iter() naturally - Add linux/uio.h for copy_to_iter() Signed-off-by: Breno Leitao Signed-off-by: Luiz Augusto von Dentz

Bluetooth: SCO: Fix data-race on sco_pi fields in sco_connect

2026-06-03T15:23:52+00:00

sco_sock_connect() copies the destination address into sco_pi(sk)->dst under lock_sock(), then releases the lock and calls sco_connect(), which reads dst, src, setting, and codec without holding lock_sock() in hci_get_route() and hci_connect_sco(). These fields may be modified concurrently by connect(), bind(), or setsockopt() on the same socket, resulting in data-races reported by KCSAN. Fix this by snapshotting dst, src, setting, and codec under lock_sock() at the start of sco_connect() before passing them to hci_get_route() and hci_connect_sco(). BUG: KCSAN: data-race in memcmp+0x45/0xb0 race at unknown origin, with read to 0xffff88800e6b0dd0 of 1 bytes by task 315 on cpu 0: memcmp+0x45/0xb0 hci_connect_acl+0x1b7/0x6b0 hci_connect_sco+0x4d/0xb30 sco_sock_connect+0x27b/0xd60 __sys_connect_file+0xbd/0xe0 __sys_connect+0xe0/0x110 __x64_sys_connect+0x40/0x50 x64_sys_call+0xcad/0x1c60 do_syscall_64+0x133/0x590 entry_SYSCALL_64_after_hwframe+0x77/0x7f Fixes: 9a8ec9e8ebb5 ("Bluetooth: SCO: Fix possible circular locking dependency on sco_connect_cfm") Signed-off-by: SeungJu Cheon Signed-off-by: Luiz Augusto von Dentz

Bluetooth: fix UAF in l2cap_sock_cleanup_listen() vs l2cap_conn_del()

2026-05-20T20:35:47+00:00

bt_accept_dequeue() unlinks a not-yet-accepted child from the parent accept queue and release_sock()s it before returning, so the returned sk has no caller reference and is unlocked. l2cap_sock_cleanup_listen() walks these children on listening-socket close. A concurrent HCI disconnect drives hci_rx_work -> l2cap_conn_del() which runs l2cap_chan_del() + l2cap_sock_kill() and frees the child sk and its l2cap_chan; cleanup_listen() then uses both: BUG: KASAN: slab-use-after-free in l2cap_sock_kill l2cap_sock_kill / l2cap_sock_cleanup_listen / __x64_sys_close Freed by: l2cap_conn_del -> l2cap_sock_close_cb -> l2cap_sock_kill This is distinct from the two fixes already in this area: commit e83f5e24da741 ("Bluetooth: serialize accept_q access") serialises the accept_q list/poll and takes temporary refs inside bt_accept_dequeue(), and CVE-2025-39860 serialises the userspace close()/accept() race by calling cleanup_listen() under lock_sock() in l2cap_sock_release(). Neither covers l2cap_conn_del() running from hci_rx_work, so this UAF still reproduces on current bluetooth/master. Take the reference at the source: bt_accept_dequeue() does sock_hold() while sk is still locked, before release_sock(); callers sock_put(). cleanup_listen() pins the chan with l2cap_chan_hold_unless_zero() under a brief child sk lock (serialising vs l2cap_sock_teardown_cb()), drops it before l2cap_chan_lock(), and skips a duplicate l2cap_sock_kill() on SOCK_DEAD. conn->lock is not taken here: cleanup_listen() runs under the parent sk lock and that would invert conn->lock -> chan->lock -> sk_lock (lockdep). KASAN/SMP: an unprivileged listen/close vs HCI-disconnect race produced 12 use-after-free reports per run before this change; 0, and no lockdep report, over 1600+ raced iterations after it on bluetooth/master. Fixes: 15f02b910562 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode") Cc: stable@vger.kernel.org Reported-by: Siwei Zhang Reviewed-by: Siwei Zhang Signed-off-by: Safa Karakuş Signed-off-by: Luiz Augusto von Dentz

Bluetooth: SCO: hold sk properly in sco_conn_ready

2026-05-06T20:21:25+00:00

sk deref in sco_conn_ready must be done either under conn->lock, or holding a refcount, to avoid concurrent close. conn->sk and parent sk is currently accessed without either, and without checking parent->sk_state: [Task 1] [Task 2] sco_sock_release sco_conn_ready sk = conn->sk lock_sock(sk) conn->sk = NULL lock_sock(sk) release_sock(sk) sco_sock_kill(sk) UAF on sk deref and similarly for access to sco_get_sock_listen() return value. Fix possible UAF by holding sk refcount in sco_conn_ready() and making sco_get_sock_listen() increase refcount. Also recheck after lock_sock that the socket is still valid. Adjust conn->sk locking so it's protected also by lock_sock() of the associated socket if any. Fixes: 27c24fda62b60 ("Bluetooth: switch to lock_sock in SCO") Signed-off-by: Pauli Virtanen Signed-off-by: Luiz Augusto von Dentz

Bluetooth: SCO: fix sleeping under spinlock in sco_conn_ready

2026-05-06T19:58:29+00:00

sco_conn_ready calls sleeping functions under conn->lock spinlock. The critical section can be reduced: conn->hcon is modified only with hdev->lock held. It is guaranteed to be held in sco_conn_ready, so conn->lock is not needed to guard it. Move taking conn->lock after lock_sock(parent). This also follows the lock ordering lock_sock() > conn->lock elsewhere in the file. Fixes: 27c24fda62b60 ("Bluetooth: switch to lock_sock in SCO") Signed-off-by: Pauli Virtanen Signed-off-by: Luiz Augusto von Dentz

Bluetooth: SCO: check for codecs->num_codecs == 1 before assigning to sco_pi(sk)->codec

2026-04-13T13:19:42+00:00

copy_struct_from_sockptr() fill 'buffer' in sco_sock_setsockopt() with zeros, so there's no real problem. But it actually looks strange to do this, without checking all of codecs->codecs[0] really comes from userspace: sco_pi(sk)->codec = codecs->codecs[0]; As only optlen < sizeof(struct bt_codecs) is checked and codecs->num_codecs is not checked against != 1, but only <= 1, and the space for the additional struct bt_codec is not checked. Note I don't understand bluetooth and I didn't do any runtime tests with this! I just found it when debugging a problem in copy_struct_from_sockptr(). I just added this to check the size is as expected: BUILD_BUG_ON(struct_size(codecs, codecs, 0) != 1); BUILD_BUG_ON(struct_size(codecs, codecs, 1) != 8); And made sure it still compiles using this: make CF=-D__CHECK_ENDIAN__ W=1ce C=1 net/bluetooth/sco.o Fixes: 3e643e4efa1e ("Bluetooth: Improve setsockopt() handling of malformed user input") Cc: Michal Luczaj Cc: Luiz Augusto von Dentz Cc: Luiz Augusto von Dentz Cc: Marcel Holtmann Cc: David Wei Cc: linux-bluetooth@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Stefan Metzmacher Signed-off-by: Luiz Augusto von Dentz

Bluetooth: SCO: fix race conditions in sco_sock_connect()

2026-04-01T20:43:53+00:00

sco_sock_connect() checks sk_state and sk_type without holding the socket lock. Two concurrent connect() syscalls on the same socket can both pass the check and enter sco_connect(), leading to use-after-free. The buggy scenario involves three participants and was confirmed with additional logging instrumentation: Thread A (connect): HCI disconnect: Thread B (connect): sco_sock_connect(sk) sco_sock_connect(sk) sk_state==BT_OPEN sk_state==BT_OPEN (pass, no lock) (pass, no lock) sco_connect(sk): sco_connect(sk): hci_dev_lock hci_dev_lock hci_connect_sco <- blocked -> hcon1 sco_conn_add->conn1 lock_sock(sk) sco_chan_add: conn1->sk = sk sk->conn = conn1 sk_state=BT_CONNECT release_sock hci_dev_unlock hci_dev_lock sco_conn_del: lock_sock(sk) sco_chan_del: sk->conn=NULL conn1->sk=NULL sk_state= BT_CLOSED SOCK_ZAPPED release_sock hci_dev_unlock (unblocked) hci_connect_sco -> hcon2 sco_conn_add -> conn2 lock_sock(sk) sco_chan_add: sk->conn=conn2 sk_state= BT_CONNECT // zombie sk! release_sock hci_dev_unlock Thread B revives a BT_CLOSED + SOCK_ZAPPED socket back to BT_CONNECT. Subsequent cleanup triggers double sock_put() and use-after-free. Meanwhile conn1 is leaked as it was orphaned when sco_conn_del() cleared the association. Fix this by: - Moving lock_sock() before the sk_state/sk_type checks in sco_sock_connect() to serialize concurrent connect attempts - Fixing the sk_type != SOCK_SEQPACKET check to actually return the error instead of just assigning it - Adding a state re-check in sco_connect() after lock_sock() to catch state changes during the window between the locks - Adding sco_pi(sk)->conn check in sco_chan_add() to prevent double-attach of a socket to multiple connections - Adding hci_conn_drop() on sco_chan_add failure to prevent HCI connection leaks Fixes: 9a8ec9e8ebb5 ("Bluetooth: SCO: Fix possible circular locking dependency on sco_connect_cfm") Signed-off-by: Cen Zhang Signed-off-by: Luiz Augusto von Dentz

Bluetooth: SCO: Fix use-after-free in sco_recv_frame() due to missing sock_hold

2026-03-19T18:42:35+00:00

sco_recv_frame() reads conn->sk under sco_conn_lock() but immediately releases the lock without holding a reference to the socket. A concurrent close() can free the socket between the lock release and the subsequent sk->sk_state access, resulting in a use-after-free. Other functions in the same file (sco_sock_timeout(), sco_conn_del()) correctly use sco_sock_hold() to safely hold a reference under the lock. Fix by using sco_sock_hold() to take a reference before releasing the lock, and adding sock_put() on all exit paths. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Hyunwoo Kim Signed-off-by: Luiz Augusto von Dentz