Subject: CVE-2023-52847: media: bttv: fix use after free error due to btv->timeout timer

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

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

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

media: bttv: fix use after free error due to btv->timeout timer

There may be some a race condition between timer function
bttv_irq_timeout and bttv_remove. The timer is setup in
probe and there is no timer_delete operation in remove
function. When it hit kfree btv, the function might still be
invoked, which will cause use after free bug.

This bug is found by static analysis, it may be false positive.

Fix it by adding del_timer_sync invoking to the remove function.

cpu0                cpu1
                  bttv_probe
                    ->timer_setup
                      ->bttv_set_dma
                        ->mod_timer;
bttv_remove
  ->kfree(btv);
                  ->bttv_irq_timeout
                    ->USE btv

The Linux kernel CVE team has assigned CVE-2023-52847 to this issue.

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

	Issue introduced in 4.15 with commit 162e6376ac58 and fixed in 4.19.299 with commit bbc3b8dd2cb7
	Issue introduced in 4.15 with commit 162e6376ac58 and fixed in 5.4.261 with commit b35fdade92c5
	Issue introduced in 4.15 with commit 162e6376ac58 and fixed in 5.10.201 with commit 2f3d9198cdae
	Issue introduced in 4.15 with commit 162e6376ac58 and fixed in 5.15.139 with commit 51c94256a83f
	Issue introduced in 4.15 with commit 162e6376ac58 and fixed in 6.1.63 with commit 20568d06f606
	Issue introduced in 4.15 with commit 162e6376ac58 and fixed in 6.5.12 with commit 1871014d6ef4
	Issue introduced in 4.15 with commit 162e6376ac58 and fixed in 6.6.2 with commit 847599fffa52
	Issue introduced in 4.15 with commit 162e6376ac58 and fixed in 6.7 with commit bd5b50b329e8

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-2023-52847
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/media/pci/bt8xx/bttv-driver.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/bbc3b8dd2cb7817e703f112d988e4f4728f0f2a9
	https://git.kernel.org/stable/c/b35fdade92c5058a5e727e233fe263b828de2c9a
	https://git.kernel.org/stable/c/2f3d9198cdae1cb079ec8652f4defacd481eab2b
	https://git.kernel.org/stable/c/51c94256a83fe4e17406c66ff3e1ad7d242d8574
	https://git.kernel.org/stable/c/20568d06f6069cb835e05eed432edf962645d226
	https://git.kernel.org/stable/c/1871014d6ef4812ad11ef7d838d73ce09d632267
	https://git.kernel.org/stable/c/847599fffa528b2cdec4e21b6bf7586dad982132
	https://git.kernel.org/stable/c/bd5b50b329e850d467e7bcc07b2b6bde3752fbda