linux-cve-announce - CVE-2025-68305: Bluetooth: hci_sock: Prevent race in socket write iter and sock bind

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Message-ID: <2025121644-CVE-2025-68305-e40b@gregkh>
Date: Tue, 16 Dec 2025 16:06:59 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-68305: Bluetooth: hci_sock: Prevent race in socket write iter and sock bind

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

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

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

Bluetooth: hci_sock: Prevent race in socket write iter and sock bind

There is a potential race condition between sock bind and socket write
iter. bind may free the same cmd via mgmt_pending before write iter sends
the cmd, just as syzbot reported in UAF[1].

Here we use hci_dev_lock to synchronize the two, thereby avoiding the
UAF mentioned in [1].

[1]
syzbot reported:
BUG: KASAN: slab-use-after-free in mgmt_pending_remove+0x3b/0x210 net/bluetooth/mgmt_util.c:316
Read of size 8 at addr ffff888077164818 by task syz.0.17/5989
Call Trace:
 mgmt_pending_remove+0x3b/0x210 net/bluetooth/mgmt_util.c:316
 set_link_security+0x5c2/0x710 net/bluetooth/mgmt.c:1918
 hci_mgmt_cmd+0x9c9/0xef0 net/bluetooth/hci_sock.c:1719
 hci_sock_sendmsg+0x6ca/0xef0 net/bluetooth/hci_sock.c:1839
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 sock_write_iter+0x279/0x360 net/socket.c:1195

Allocated by task 5989:
 mgmt_pending_add+0x35/0x140 net/bluetooth/mgmt_util.c:296
 set_link_security+0x557/0x710 net/bluetooth/mgmt.c:1910
 hci_mgmt_cmd+0x9c9/0xef0 net/bluetooth/hci_sock.c:1719
 hci_sock_sendmsg+0x6ca/0xef0 net/bluetooth/hci_sock.c:1839
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x21c/0x270 net/socket.c:742
 sock_write_iter+0x279/0x360 net/socket.c:1195

Freed by task 5991:
 mgmt_pending_free net/bluetooth/mgmt_util.c:311 [inline]
 mgmt_pending_foreach+0x30d/0x380 net/bluetooth/mgmt_util.c:257
 mgmt_index_removed+0x112/0x2f0 net/bluetooth/mgmt.c:9477
 hci_sock_bind+0xbe9/0x1000 net/bluetooth/hci_sock.c:1314

The Linux kernel CVE team has assigned CVE-2025-68305 to this issue.


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

	Issue introduced in 6.6.94 with commit bdd56875c6926d8009914f427df71797693e90d4 and fixed in 6.6.119 with commit fe68510fc99bb4b88c9c611f83699749002d515a
	Issue introduced in 6.12.34 with commit 4e83f2dbb2bf677e614109df24426c4dded472d4 and fixed in 6.12.61 with commit e90c05fc5bbea956450a05cc3b36b8fa29cf195e
	Issue introduced in 6.16 with commit 6fe26f694c824b8a4dbf50c635bee1302e3f099c and fixed in 6.17.11 with commit 69fcb0344bc0dd5b13d7e4e98f8b6bf25a6d4ff7
	Issue introduced in 6.16 with commit 6fe26f694c824b8a4dbf50c635bee1302e3f099c and fixed in 6.18 with commit 89bb613511cc21ed5ba6bddc1c9b9ae9c0dad392
	Issue introduced in 6.15.3 with commit d7882db79135c829a922daf3571f33ea1e056ae3

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-2025-68305
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_sock.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/fe68510fc99bb4b88c9c611f83699749002d515a
	https://git.kernel.org/stable/c/e90c05fc5bbea956450a05cc3b36b8fa29cf195e
	https://git.kernel.org/stable/c/69fcb0344bc0dd5b13d7e4e98f8b6bf25a6d4ff7
	https://git.kernel.org/stable/c/89bb613511cc21ed5ba6bddc1c9b9ae9c0dad392