CVE-2026-74535: Bluetooth: ISO: avoid deadlocks in iso_sock_timeout

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

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

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

Bluetooth: ISO: avoid deadlocks in iso_sock_timeout

iso_sock_timeout() takes lock_sock, so sync disabling the timer while
holding that lock may deadlock.

iso_sock_timeout() may also run concurrently with iso_conn_del(), which
leads to UAF

        [Task 1]                      [Task hdev->workqueue]
        iso_sock_timeout              iso_conn_del
          iso_conn_hold_unless_zero     iso_chan_del
                           `------------> iso_conn_put
                                      caller frees hcon
          iso_conn_put
            iso_conn_free
              conn->hcon->iso_data = NULL; /* UAF */

Fix the deadlock by removing the disable from the lock_sock sections.
Move the timer from iso_conn to iso_pinfo to decouple it from iso_conn
which may need to be freed in lock_sock section. Convert some of the
clear_timer to disable_timer.

The Linux kernel CVE team has assigned CVE-2026-74535 to this issue.


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

	Issue introduced in 6.12.2 with commit a58d0f5dac322e16cc75334d000666512341bde5 and fixed in 6.12.103 with commit 16d89a63e08280abeef7218970a3bbd7ca62b021
	Issue introduced in 6.13 with commit dc26097bdb864a0d5955b9a25e43376ffc1af99b and fixed in 6.18.44 with commit 82e982f54f962f72646868ddbb2c3bd9ea178568
	Issue introduced in 6.13 with commit dc26097bdb864a0d5955b9a25e43376ffc1af99b and fixed in 7.1.8 with commit 3c3d5f85db80145636bb991a6005e2760012b985
	Issue introduced in 6.13 with commit dc26097bdb864a0d5955b9a25e43376ffc1af99b and fixed in 7.2-rc6 with commit 200fa1629c57a3ca2b03d3ca63fd3a9bfd910c43
	Issue introduced in 6.11.11 with commit f53e7489273dc2bb307bf50f319b3762d45534f0

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-2026-74535
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/iso.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/16d89a63e08280abeef7218970a3bbd7ca62b021
	https://git.kernel.org/stable/c/82e982f54f962f72646868ddbb2c3bd9ea178568
	https://git.kernel.org/stable/c/3c3d5f85db80145636bb991a6005e2760012b985
	https://git.kernel.org/stable/c/200fa1629c57a3ca2b03d3ca63fd3a9bfd910c43