CVE-2026-72119: can: bcm: extend bcm_tx_lock usage for data and timer updates

From: Greg Kroah-Hartman <[email protected]>

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

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

can: bcm: extend bcm_tx_lock usage for data and timer updates

Stage new CAN frame content for an existing tx op into a kmalloc()'d
buffer and validate it there, mirroring the approach already used in
bcm_rx_setup(). Only copy the validated data into op->frames while
holding op->bcm_tx_lock, so bcm_can_tx() and bcm_tx_timeout_handler()
can no longer observe a partially updated or unvalidated frame.

Add a missing error path for memcpy_from_msg() when copying CAN frame
data from userspace.

Also move the kt_ival1/kt_ival2/ival1/ival2 updates in bcm_tx_setup()
under op->bcm_tx_lock, and read kt_ival1/kt_ival2/count under the same
lock in bcm_tx_set_expiry() and bcm_tx_timeout_handler(), closing the
torn 64-bit ktime_t read on 32-bit platforms.

The Linux kernel CVE team has assigned CVE-2026-72119 to this issue.


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

	Issue introduced in 6.6.93 with commit 76c84c3728178b2d38d5604e399dfe8b0752645e and fixed in 6.6.148 with commit 52f06e7603780de100233713ddaf971d422e10ef
	Issue introduced in 6.12.31 with commit cc55dd28c20a6611e30596019b3b2f636819a4c0 and fixed in 6.12.101 with commit 972fd66bb08fdef1090abe43196ca8da07216d13
	Issue introduced in 6.15 with commit c2aba69d0c36a496ab4f2e81e9c2b271f2693fd7 and fixed in 6.18.42 with commit bd46f55dec608daa44b45dcf3328517630ad8e40
	Issue introduced in 6.15 with commit c2aba69d0c36a496ab4f2e81e9c2b271f2693fd7 and fixed in 7.1.5 with commit 337f966c00662d81ad82cf5a4bbb150b2e32c0d4
	Issue introduced in 6.15 with commit c2aba69d0c36a496ab4f2e81e9c2b271f2693fd7 and fixed in 7.2-rc4 with commit 12ce799f7ab1e05bd8fbf79e46f403bfe5597ebc
	Issue introduced in 5.4.294 with commit 8f1c022541bf5a923c8d6fa483112c15250f30a4
	Issue introduced in 5.10.238 with commit 7595de7bc56e0e52b74e56c90f7e247bf626d628
	Issue introduced in 5.15.185 with commit fbd8fdc2b218e979cfe422b139b8f74c12419d1f
	Issue introduced in 6.1.141 with commit 2a437b86ac5a9893c902f30ef66815bf13587bf6
	Issue introduced in 6.14.9 with commit c4e8a172501e677ebd8ea9d9161d97dc4df56fbd

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-2026-72119
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/can/bcm.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/52f06e7603780de100233713ddaf971d422e10ef
	https://git.kernel.org/stable/c/972fd66bb08fdef1090abe43196ca8da07216d13
	https://git.kernel.org/stable/c/bd46f55dec608daa44b45dcf3328517630ad8e40
	https://git.kernel.org/stable/c/337f966c00662d81ad82cf5a4bbb150b2e32c0d4
	https://git.kernel.org/stable/c/12ce799f7ab1e05bd8fbf79e46f403bfe5597ebc