linux-cve-announce - CVE-2023-53673: Bluetooth: hci_event: call disconnect callback before deleting conn

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [day] [month] [year] [list]
Message-ID: <2025100706-CVE-2023-53673-36b9@gregkh>
Date: Tue,  7 Oct 2025 17:21:32 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2023-53673: Bluetooth: hci_event: call disconnect callback before deleting conn

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: hci_event: call disconnect callback before deleting conn

In hci_cs_disconnect, we do hci_conn_del even if disconnection failed.

ISO, L2CAP and SCO connections refer to the hci_conn without
hci_conn_get, so disconn_cfm must be called so they can clean up their
conn, otherwise use-after-free occurs.

ISO:
==========================================================
iso_sock_connect:880: sk 00000000eabd6557
iso_connect_cis:356: 70:1a:b8:98:ff:a2 -> 28:3d:c2:4a:7e:da
...
iso_conn_add:140: hcon 000000001696f1fd conn 00000000b6251073
hci_dev_put:1487: hci0 orig refcnt 17
__iso_chan_add:214: conn 00000000b6251073
iso_sock_clear_timer:117: sock 00000000eabd6557 state 3
...
hci_rx_work:4085: hci0 Event packet
hci_event_packet:7601: hci0: event 0x0f
hci_cmd_status_evt:4346: hci0: opcode 0x0406
hci_cs_disconnect:2760: hci0: status 0x0c
hci_sent_cmd_data:3107: hci0 opcode 0x0406
hci_conn_del:1151: hci0 hcon 000000001696f1fd handle 2560
hci_conn_unlink:1102: hci0: hcon 000000001696f1fd
hci_conn_drop:1451: hcon 00000000d8521aaf orig refcnt 2
hci_chan_list_flush:2780: hcon 000000001696f1fd
hci_dev_put:1487: hci0 orig refcnt 21
hci_dev_put:1487: hci0 orig refcnt 20
hci_req_cmd_complete:3978: opcode 0x0406 status 0x0c
... <no iso_* activity on sk/conn> ...
iso_sock_sendmsg:1098: sock 00000000dea5e2e0, sk 00000000eabd6557
BUG: kernel NULL pointer dereference, address: 0000000000000668
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP PTI
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014
RIP: 0010:iso_sock_sendmsg (net/bluetooth/iso.c:1112) bluetooth
==========================================================

L2CAP:
==================================================================
hci_cmd_status_evt:4359: hci0: opcode 0x0406
hci_cs_disconnect:2760: hci0: status 0x0c
hci_sent_cmd_data:3085: hci0 opcode 0x0406
hci_conn_del:1151: hci0 hcon ffff88800c999000 handle 3585
hci_conn_unlink:1102: hci0: hcon ffff88800c999000
hci_chan_list_flush:2780: hcon ffff88800c999000
hci_chan_del:2761: hci0 hcon ffff88800c999000 chan ffff888018ddd280
...
BUG: KASAN: slab-use-after-free in hci_send_acl+0x2d/0x540 [bluetooth]
Read of size 8 at addr ffff888018ddd298 by task bluetoothd/1175

CPU: 0 PID: 1175 Comm: bluetoothd Tainted: G            E      6.4.0-rc4+ #2
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x5b/0x90
 print_report+0xcf/0x670
 ? __virt_addr_valid+0xf8/0x180
 ? hci_send_acl+0x2d/0x540 [bluetooth]
 kasan_report+0xa8/0xe0
 ? hci_send_acl+0x2d/0x540 [bluetooth]
 hci_send_acl+0x2d/0x540 [bluetooth]
 ? __pfx___lock_acquire+0x10/0x10
 l2cap_chan_send+0x1fd/0x1300 [bluetooth]
 ? l2cap_sock_sendmsg+0xf2/0x170 [bluetooth]
 ? __pfx_l2cap_chan_send+0x10/0x10 [bluetooth]
 ? lock_release+0x1d5/0x3c0
 ? mark_held_locks+0x1a/0x90
 l2cap_sock_sendmsg+0x100/0x170 [bluetooth]
 sock_write_iter+0x275/0x280
 ? __pfx_sock_write_iter+0x10/0x10
 ? __pfx___lock_acquire+0x10/0x10
 do_iter_readv_writev+0x176/0x220
 ? __pfx_do_iter_readv_writev+0x10/0x10
 ? find_held_lock+0x83/0xa0
 ? selinux_file_permission+0x13e/0x210
 do_iter_write+0xda/0x340
 vfs_writev+0x1b4/0x400
 ? __pfx_vfs_writev+0x10/0x10
 ? __seccomp_filter+0x112/0x750
 ? populate_seccomp_data+0x182/0x220
 ? __fget_light+0xdf/0x100
 ? do_writev+0x19d/0x210
 do_writev+0x19d/0x210
 ? __pfx_do_writev+0x10/0x10
 ? mark_held_locks+0x1a/0x90
 do_syscall_64+0x60/0x90
 ? lockdep_hardirqs_on_prepare+0x149/0x210
 ? do_syscall_64+0x6c/0x90
 ? lockdep_hardirqs_on_prepare+0x149/0x210
 entry_SYSCALL_64_after_hwframe+0x72/0xdc
RIP: 0033:0x7ff45cb23e64
Code: 15 d1 1f 0d 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 f3 0f 1e fa 80 3d 9d a7 0d 00 00 74 13 b8 14 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 48 83 ec 28 89 54 24 1c 48 89
RSP: 002b:00007fff21ae09b8 EFLAGS: 00000202 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007ff45cb23e64
RDX: 0000000000000001 RSI: 00007fff21ae0aa0 RDI: 0000000000000017
RBP: 00007fff21ae0aa0 R08: 000000000095a8a0 R09: 0000607000053f40
R10: 0000000000000001 R11: 0000000000000202 R12: 00007fff21ae0ac0
R13: 00000fffe435c150 R14: 00007fff21ae0a80 R15: 000060f000000040
 </TASK>

Allocated by task 771:
 kasan_save_stack+0x33/0x60
 kasan_set_track+0x25/0x30
 __kasan_kmalloc+0xaa/0xb0
 hci_chan_create+0x67/0x1b0 [bluetooth]
 l2cap_conn_add.part.0+0x17/0x590 [bluetooth]
 l2cap_connect_cfm+0x266/0x6b0 [bluetooth]
 hci_le_remote_feat_complete_evt+0x167/0x310 [bluetooth]
 hci_event_packet+0x38d/0x800 [bluetooth]
 hci_rx_work+0x287/0xb20 [bluetooth]
 process_one_work+0x4f7/0x970
 worker_thread+0x8f/0x620
 kthread+0x17f/0x1c0
 ret_from_fork+0x2c/0x50

Freed by task 771:
 kasan_save_stack+0x33/0x60
 kasan_set_track+0x25/0x30
 kasan_save_free_info+0x2e/0x50
 ____kasan_slab_free+0x169/0x1c0
 slab_free_freelist_hook+0x9e/0x1c0
 __kmem_cache_free+0xc0/0x310
 hci_chan_list_flush+0x46/0x90 [bluetooth]
 hci_conn_cleanup+0x7d/0x330 [bluetooth]
 hci_cs_disconnect+0x35d/0x530 [bluetooth]
 hci_cmd_status_evt+0xef/0x2b0 [bluetooth]
 hci_event_packet+0x38d/0x800 [bluetooth]
 hci_rx_work+0x287/0xb20 [bluetooth]
 process_one_work+0x4f7/0x970
 worker_thread+0x8f/0x620
 kthread+0x17f/0x1c0
 ret_from_fork+0x2c/0x50
==================================================================

The Linux kernel CVE team has assigned CVE-2023-53673 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 5.7 with commit b8d290525e3972b5e876b2649a42bf4081d753fe and fixed in 6.1.42 with commit 59bd1e476bbc7bc6dff3c61bba787095a4839796
	Issue introduced in 5.7 with commit b8d290525e3972b5e876b2649a42bf4081d753fe and fixed in 6.4.7 with commit 093a07052406b363b1b2ab489e17dbadaf3e509b
	Issue introduced in 5.7 with commit b8d290525e3972b5e876b2649a42bf4081d753fe and fixed in 6.5 with commit 7f7cfcb6f0825652973b780f248603e23f16ee90

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2023-53673
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	net/bluetooth/hci_event.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/59bd1e476bbc7bc6dff3c61bba787095a4839796
	https://git.kernel.org/stable/c/093a07052406b363b1b2ab489e17dbadaf3e509b
	https://git.kernel.org/stable/c/7f7cfcb6f0825652973b780f248603e23f16ee90