kernel/linux.git/net/bluetooth/sco.c, branch v6.1.174

Bluetooth: SCO: fix race conditions in sco_sock_connect()

2026-04-11T12:16:23+00:00

[ Upstream commit 8a5b0135d4a5d9683203a3d9a12a711ccec5936b ] 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 Signed-off-by: Sasha Levin

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

2026-04-11T12:16:05+00:00

[ Upstream commit 598dbba9919c5e36c54fe1709b557d64120cb94b ] 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 Signed-off-by: Sasha Levin

Bluetooth: SCO: Fix UAF on sco_conn_free

2025-12-06T21:12:26+00:00

[ Upstream commit ecb9a843be4d6fd710d7026e359f21015a062572 ] BUG: KASAN: slab-use-after-free in sco_conn_free net/bluetooth/sco.c:87 [inline] BUG: KASAN: slab-use-after-free in kref_put include/linux/kref.h:65 [inline] BUG: KASAN: slab-use-after-free in sco_conn_put+0xdd/0x410 net/bluetooth/sco.c:107 Write of size 8 at addr ffff88811cb96b50 by task kworker/u17:4/352 CPU: 1 UID: 0 PID: 352 Comm: kworker/u17:4 Not tainted 6.17.0-rc5-g717368f83676 #4 PREEMPT(voluntary) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Workqueue: hci13 hci_cmd_sync_work Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x10b/0x170 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x191/0x550 mm/kasan/report.c:482 kasan_report+0xc4/0x100 mm/kasan/report.c:595 sco_conn_free net/bluetooth/sco.c:87 [inline] kref_put include/linux/kref.h:65 [inline] sco_conn_put+0xdd/0x410 net/bluetooth/sco.c:107 sco_connect_cfm+0xb4/0xae0 net/bluetooth/sco.c:1441 hci_connect_cfm include/net/bluetooth/hci_core.h:2082 [inline] hci_conn_failed+0x20a/0x2e0 net/bluetooth/hci_conn.c:1313 hci_conn_unlink+0x55f/0x810 net/bluetooth/hci_conn.c:1121 hci_conn_del+0xb6/0x1110 net/bluetooth/hci_conn.c:1147 hci_abort_conn_sync+0x8c5/0xbb0 net/bluetooth/hci_sync.c:5689 hci_cmd_sync_work+0x281/0x380 net/bluetooth/hci_sync.c:332 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0x77e/0x1040 kernel/workqueue.c:3319 worker_thread+0xbee/0x1200 kernel/workqueue.c:3400 kthread+0x3c7/0x870 kernel/kthread.c:463 ret_from_fork+0x13a/0x1e0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Allocated by task 31370: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x30/0x70 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:388 [inline] __kasan_kmalloc+0x82/0x90 mm/kasan/common.c:405 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4382 [inline] __kmalloc_noprof+0x22f/0x390 mm/slub.c:4394 kmalloc_noprof include/linux/slab.h:909 [inline] sk_prot_alloc+0xae/0x220 net/core/sock.c:2239 sk_alloc+0x34/0x5a0 net/core/sock.c:2295 bt_sock_alloc+0x3c/0x330 net/bluetooth/af_bluetooth.c:151 sco_sock_alloc net/bluetooth/sco.c:562 [inline] sco_sock_create+0xc0/0x350 net/bluetooth/sco.c:593 bt_sock_create+0x161/0x3b0 net/bluetooth/af_bluetooth.c:135 __sock_create+0x3ad/0x780 net/socket.c:1589 sock_create net/socket.c:1647 [inline] __sys_socket_create net/socket.c:1684 [inline] __sys_socket+0xd5/0x330 net/socket.c:1731 __do_sys_socket net/socket.c:1745 [inline] __se_sys_socket net/socket.c:1743 [inline] __x64_sys_socket+0x7a/0x90 net/socket.c:1743 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xc7/0x240 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 31374: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x30/0x70 mm/kasan/common.c:68 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x3d/0x50 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2428 [inline] slab_free mm/slub.c:4701 [inline] kfree+0x199/0x3b0 mm/slub.c:4900 sk_prot_free net/core/sock.c:2278 [inline] __sk_destruct+0x4aa/0x630 net/core/sock.c:2373 sco_sock_release+0x2ad/0x300 net/bluetooth/sco.c:1333 __sock_release net/socket.c:649 [inline] sock_close+0xb8/0x230 net/socket.c:1439 __fput+0x3d1/0x9e0 fs/file_table.c:468 task_work_run+0x206/0x2a0 kernel/task_work.c:227 get_signal+0x1201/0x1410 kernel/signal.c:2807 arch_do_signal_or_restart+0x34/0x740 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x68/0xc0 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x1dd/0x240 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f Reported-by: cen zhang Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin

Revert "Bluetooth: hci_core: Fix sleeping function called from invalid context"

2025-03-28T20:58:49+00:00

[ Upstream commit ab6ab707a4d060a51c45fc13e3b2228d5f7c0b87 ] This reverts commit 4d94f05558271654670d18c26c912da0c1c15549 which has problems (see [1]) and is no longer needed since 581dd2dc168f ("Bluetooth: hci_event: Fix using rcu_read_(un)lock while iterating") has reworked the code where the original bug has been found. [1] Link: https://lore.kernel.org/linux-bluetooth/877c55ci1r.wl-tiwai@suse.de/T/#t Fixes: 4d94f0555827 ("Bluetooth: hci_core: Fix sleeping function called from invalid context") Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin

Bluetooth: hci_core: Fix sleeping function called from invalid context

2025-01-09T12:30:04+00:00

[ Upstream commit 4d94f05558271654670d18c26c912da0c1c15549 ] This reworks hci_cb_list to not use mutex hci_cb_list_lock to avoid bugs like the bellow: BUG: sleeping function called from invalid context at kernel/locking/mutex.c:585 in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 5070, name: kworker/u9:2 preempt_count: 0, expected: 0 RCU nest depth: 1, expected: 0 4 locks held by kworker/u9:2/5070: #0: ffff888015be3948 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3229 [inline] #0: ffff888015be3948 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_scheduled_works+0x8e0/0x1770 kernel/workqueue.c:3335 #1: ffffc90003b6fd00 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3230 [inline] #1: ffffc90003b6fd00 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_scheduled_works+0x91b/0x1770 kernel/workqueue.c:3335 #2: ffff8880665d0078 (&hdev->lock){+.+.}-{3:3}, at: hci_le_create_big_complete_evt+0xcf/0xae0 net/bluetooth/hci_event.c:6914 #3: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline] #3: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline] #3: ffffffff8e132020 (rcu_read_lock){....}-{1:2}, at: hci_le_create_big_complete_evt+0xdb/0xae0 net/bluetooth/hci_event.c:6915 CPU: 0 PID: 5070 Comm: kworker/u9:2 Not tainted 6.8.0-syzkaller-08073-g480e035fc4c7 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Workqueue: hci0 hci_rx_work Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114 __might_resched+0x5d4/0x780 kernel/sched/core.c:10187 __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0xc1/0xd70 kernel/locking/mutex.c:752 hci_connect_cfm include/net/bluetooth/hci_core.h:2004 [inline] hci_le_create_big_complete_evt+0x3d9/0xae0 net/bluetooth/hci_event.c:6939 hci_event_func net/bluetooth/hci_event.c:7514 [inline] hci_event_packet+0xa53/0x1540 net/bluetooth/hci_event.c:7569 hci_rx_work+0x3e8/0xca0 net/bluetooth/hci_core.c:4171 process_one_work kernel/workqueue.c:3254 [inline] process_scheduled_works+0xa00/0x1770 kernel/workqueue.c:3335 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416 kthread+0x2f0/0x390 kernel/kthread.c:388 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 Reported-by: syzbot+2fb0835e0c9cefc34614@syzkaller.appspotmail.com Tested-by: syzbot+2fb0835e0c9cefc34614@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=2fb0835e0c9cefc34614 Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin

Bluetooth: SCO: Add support for 16 bits transparent voice setting

2024-12-19T17:08:57+00:00

[ Upstream commit 29a651451e6c264f58cd9d9a26088e579d17b242 ] The voice setting is used by sco_connect() or sco_conn_defer_accept() after being set by sco_sock_setsockopt(). The PCM part of the voice setting is used for offload mode through PCM chipset port. This commits add support for mSBC 16 bits offloading, i.e. audio data not transported over HCI. The BCM4349B1 supports 16 bits transparent data on its I2S port. If BT_VOICE_TRANSPARENT is used when accepting a SCO connection, this gives only garbage audio while using BT_VOICE_TRANSPARENT_16BIT gives correct audio. This has been tested with connection to iPhone 14 and Samsung S24. Fixes: ad10b1a48754 ("Bluetooth: Add Bluetooth socket voice option") Signed-off-by: Frédéric Danis Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin

Bluetooth: SCO: Fix UAF on sco_sock_timeout

2024-11-01T00:56:05+00:00

[ Upstream commit 1bf4470a3939c678fb822073e9ea77a0560bc6bb ] conn->sk maybe have been unlinked/freed while waiting for sco_conn_lock so this checks if the conn->sk is still valid by checking if it part of sco_sk_list. Reported-by: syzbot+4c0d0c4cde787116d465@syzkaller.appspotmail.com Tested-by: syzbot+4c0d0c4cde787116d465@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=4c0d0c4cde787116d465 Fixes: ba316be1b6a0 ("Bluetooth: schedule SCO timeouts with delayed_work") Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin

Bluetooth: SCO: fix sco_conn related locking and validity issues

2024-09-08T05:53:12+00:00

commit 3dcaa192ac2159193bc6ab57bc5369dcb84edd8e upstream. Operations that check/update sk_state and access conn should hold lock_sock, otherwise they can race. The order of taking locks is hci_dev_lock > lock_sock > sco_conn_lock, which is how it is in connect/disconnect_cfm -> sco_conn_del -> sco_chan_del. Fix locking in sco_connect to take lock_sock around updating sk_state and conn. sco_conn_del must not occur during sco_connect, as it frees the sco_conn. Hold hdev->lock longer to prevent that. sco_conn_add shall return sco_conn with valid hcon. Make it so also when reusing an old SCO connection waiting for disconnect timeout (see __sco_sock_close where conn->hcon is set to NULL). This should not reintroduce the issue fixed in the earlier commit 9a8ec9e8ebb5 ("Bluetooth: SCO: Fix possible circular locking dependency on sco_connect_cfm"), the relevant fix of releasing lock_sock in sco_sock_connect before acquiring hdev->lock is retained. These changes mirror similar fixes earlier in ISO sockets. Fixes: 9a8ec9e8ebb5 ("Bluetooth: SCO: Fix possible circular locking dependency on sco_connect_cfm") Signed-off-by: Pauli Virtanen Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Greg Kroah-Hartman

Bluetooth: SCO: Fix possible circular locking dependency on sco_connect_cfm

2024-09-08T05:53:12+00:00

commit 9a8ec9e8ebb5a7c0cfbce2d6b4a6b67b2b78e8f3 upstream. This attempts to fix the following trace: ====================================================== WARNING: possible circular locking dependency detected 6.3.0-rc2-g0b93eeba4454 #4703 Not tainted ------------------------------------------------------ kworker/u3:0/46 is trying to acquire lock: ffff888001fd9130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_connect_cfm+0x118/0x4a0 but task is already holding lock: ffffffff831e3340 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_sync_conn_complete_evt+0x1ad/0x3d0 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (hci_cb_list_lock){+.+.}-{3:3}: __mutex_lock+0x13b/0xcc0 hci_sync_conn_complete_evt+0x1ad/0x3d0 hci_event_packet+0x55c/0x7c0 hci_rx_work+0x34c/0xa00 process_one_work+0x575/0x910 worker_thread+0x89/0x6f0 kthread+0x14e/0x180 ret_from_fork+0x2b/0x50 -> #1 (&hdev->lock){+.+.}-{3:3}: __mutex_lock+0x13b/0xcc0 sco_sock_connect+0xfc/0x630 __sys_connect+0x197/0x1b0 __x64_sys_connect+0x37/0x50 do_syscall_64+0x42/0x90 entry_SYSCALL_64_after_hwframe+0x70/0xda -> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}: __lock_acquire+0x18cc/0x3740 lock_acquire+0x151/0x3a0 lock_sock_nested+0x32/0x80 sco_connect_cfm+0x118/0x4a0 hci_sync_conn_complete_evt+0x1e6/0x3d0 hci_event_packet+0x55c/0x7c0 hci_rx_work+0x34c/0xa00 process_one_work+0x575/0x910 worker_thread+0x89/0x6f0 kthread+0x14e/0x180 ret_from_fork+0x2b/0x50 other info that might help us debug this: Chain exists of: sk_lock-AF_BLUETOOTH-BTPROTO_SCO --> &hdev->lock --> hci_cb_list_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(hci_cb_list_lock); lock(&hdev->lock); lock(hci_cb_list_lock); lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO); *** DEADLOCK *** 4 locks held by kworker/u3:0/46: #0: ffff8880028d1130 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_one_work+0x4c0/0x910 #1: ffff8880013dfde0 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work+0x4c0/0x910 #2: ffff8880025d8070 (&hdev->lock){+.+.}-{3:3}, at: hci_sync_conn_complete_evt+0xa6/0x3d0 #3: ffffffffb79e3340 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_sync_conn_complete_evt+0x1ad/0x3d0 Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Greg Kroah-Hartman

Bluetooth: Consolidate code around sk_alloc into a helper function

2024-06-12T09:03:20+00:00

[ Upstream commit 6bfa273e533d7b25eee3d74e28a7fe8e6a8e7a93 ] This consolidates code around sk_alloc into bt_sock_alloc which does take care of common initialization. Signed-off-by: Luiz Augusto von Dentz Stable-dep-of: ce60b9231b66 ("Bluetooth: compute LE flow credits based on recvbuf space") Signed-off-by: Sasha Levin