linux-cve-announce - CVE-2022-50725: media: vidtv: Fix use-after-free in vidtv_bridge_dvb

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Message-ID: <2025122418-CVE-2022-50725-967f@gregkh>
Date: Wed, 24 Dec 2025 13:26:24 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50725: media: vidtv: Fix use-after-free in vidtv_bridge_dvb_init()

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

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

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

media: vidtv: Fix use-after-free in vidtv_bridge_dvb_init()

KASAN reports a use-after-free:
BUG: KASAN: use-after-free in dvb_dmxdev_release+0x4d5/0x5d0 [dvb_core]
Call Trace:
 ...
 dvb_dmxdev_release+0x4d5/0x5d0 [dvb_core]
 vidtv_bridge_probe+0x7bf/0xa40 [dvb_vidtv_bridge]
 platform_probe+0xb6/0x170
 ...
Allocated by task 1238:
 ...
 dvb_register_device+0x1a7/0xa70 [dvb_core]
 dvb_dmxdev_init+0x2af/0x4a0 [dvb_core]
 vidtv_bridge_probe+0x766/0xa40 [dvb_vidtv_bridge]
 ...
Freed by task 1238:
 dvb_register_device+0x6d2/0xa70 [dvb_core]
 dvb_dmxdev_init+0x2af/0x4a0 [dvb_core]
 vidtv_bridge_probe+0x766/0xa40 [dvb_vidtv_bridge]
 ...

It is because the error handling in vidtv_bridge_dvb_init() is wrong.

First, vidtv_bridge_dmx(dev)_init() will clean themselves when fail, but
goto fail_dmx(_dev): calls release functions again, which causes
use-after-free.

Also, in fail_fe, fail_tuner_probe and fail_demod_probe, j = i will cause
out-of-bound when i finished its loop (i == NUM_FE). And the loop
releasing is wrong, although now NUM_FE is 1 so it won't cause problem.

Fix this by correctly releasing everything.

The Linux kernel CVE team has assigned CVE-2022-50725 to this issue.

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

	Issue introduced in 5.10 with commit f90cf6079bf67988f8b1ad1ade70fc89d0080905 and fixed in 5.10.163 with commit 0369af6fe33d4053899b121b32e91f870b2cf0ae
	Issue introduced in 5.10 with commit f90cf6079bf67988f8b1ad1ade70fc89d0080905 and fixed in 5.15.86 with commit c290aa527fd832d278c6388a3ba53a9890fbd74a
	Issue introduced in 5.10 with commit f90cf6079bf67988f8b1ad1ade70fc89d0080905 and fixed in 6.0.16 with commit 06398ce69571a43a8a0dd0f1bfe35d221f726a6a
	Issue introduced in 5.10 with commit f90cf6079bf67988f8b1ad1ade70fc89d0080905 and fixed in 6.1.2 with commit 8a204a0b4a0d105229735222c515759ea2b126c1
	Issue introduced in 5.10 with commit f90cf6079bf67988f8b1ad1ade70fc89d0080905 and fixed in 6.2 with commit ba8d9405935097e296bcf7a942c3a01df0edb865

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-2022-50725
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/test-drivers/vidtv/vidtv_bridge.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/0369af6fe33d4053899b121b32e91f870b2cf0ae
	https://git.kernel.org/stable/c/c290aa527fd832d278c6388a3ba53a9890fbd74a
	https://git.kernel.org/stable/c/06398ce69571a43a8a0dd0f1bfe35d221f726a6a
	https://git.kernel.org/stable/c/8a204a0b4a0d105229735222c515759ea2b126c1
	https://git.kernel.org/stable/c/ba8d9405935097e296bcf7a942c3a01df0edb865