linux-cve-announce - CVE-2025-40308: Bluetooth: bcsp: receive data only if registered

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Message-ID: <2025120821-CVE-2025-40308-0613@gregkh>
Date: Mon,  8 Dec 2025 09:47:32 +0900
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-40308: Bluetooth: bcsp: receive data only if registered

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

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

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

Bluetooth: bcsp: receive data only if registered

Currently, bcsp_recv() can be called even when the BCSP protocol has not
been registered. This leads to a NULL pointer dereference, as shown in
the following stack trace:

    KASAN: null-ptr-deref in range [0x0000000000000108-0x000000000000010f]
    RIP: 0010:bcsp_recv+0x13d/0x1740 drivers/bluetooth/hci_bcsp.c:590
    Call Trace:
     <TASK>
     hci_uart_tty_receive+0x194/0x220 drivers/bluetooth/hci_ldisc.c:627
     tiocsti+0x23c/0x2c0 drivers/tty/tty_io.c:2290
     tty_ioctl+0x626/0xde0 drivers/tty/tty_io.c:2706
     vfs_ioctl fs/ioctl.c:51 [inline]
     __do_sys_ioctl fs/ioctl.c:907 [inline]
     __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
     do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
     do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
     entry_SYSCALL_64_after_hwframe+0x77/0x7f

To prevent this, ensure that the HCI_UART_REGISTERED flag is set before
processing received data. If the protocol is not registered, return
-EUNATCH.

The Linux kernel CVE team has assigned CVE-2025-40308 to this issue.


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

	Fixed in 5.4.302 with commit 39a7d40314b6288cfa2d13269275e9247a7a055a
	Fixed in 5.10.247 with commit 164586725b47f9d61912e6bf17dbaffeff11710b
	Fixed in 5.15.197 with commit b65ca9708bfbf47d8b7bd44b7c574bd16798e9c9
	Fixed in 6.1.159 with commit 8b892dbef3887dbe9afdc7176d1a5fd90e1636aa
	Fixed in 6.6.117 with commit 799cd62cbcc3f12ee04b33ef390ff7d41c37d671
	Fixed in 6.12.58 with commit b420a4c7f915fc1c94ad1f6ca740acc046d94334
	Fixed in 6.17.8 with commit 55c1519fca830f59a10bbf9aa8209c87b06cf7bc
	Fixed in 6.18 with commit ca94b2b036c22556c3a66f1b80f490882deef7a6

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-2025-40308
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:
	drivers/bluetooth/hci_bcsp.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/39a7d40314b6288cfa2d13269275e9247a7a055a
	https://git.kernel.org/stable/c/164586725b47f9d61912e6bf17dbaffeff11710b
	https://git.kernel.org/stable/c/b65ca9708bfbf47d8b7bd44b7c574bd16798e9c9
	https://git.kernel.org/stable/c/8b892dbef3887dbe9afdc7176d1a5fd90e1636aa
	https://git.kernel.org/stable/c/799cd62cbcc3f12ee04b33ef390ff7d41c37d671
	https://git.kernel.org/stable/c/b420a4c7f915fc1c94ad1f6ca740acc046d94334
	https://git.kernel.org/stable/c/55c1519fca830f59a10bbf9aa8209c87b06cf7bc
	https://git.kernel.org/stable/c/ca94b2b036c22556c3a66f1b80f490882deef7a6