linux-cve-announce - CVE-2022-50101: video: fbdev: vt8623fb: Check the size of screen before memset

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Message-ID: <2025061804-CVE-2022-50101-9556@gregkh>
Date: Wed, 18 Jun 2025 13:02:46 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50101: video: fbdev: vt8623fb: Check the size of screen before memset_io()

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

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

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

video: fbdev: vt8623fb: Check the size of screen before memset_io()

In the function vt8623fb_set_par(), the value of 'screen_size' is
calculated by the user input. If the user provides the improper value,
the value of 'screen_size' may larger than 'info->screen_size', which
may cause the following bug:

[  583.339036] BUG: unable to handle page fault for address: ffffc90005000000
[  583.339049] #PF: supervisor write access in kernel mode
[  583.339052] #PF: error_code(0x0002) - not-present page
[  583.339074] RIP: 0010:memset_orig+0x33/0xb0
[  583.339110] Call Trace:
[  583.339118]  vt8623fb_set_par+0x11cd/0x21e0
[  583.339146]  fb_set_var+0x604/0xeb0
[  583.339181]  do_fb_ioctl+0x234/0x670
[  583.339209]  fb_ioctl+0xdd/0x130

Fix the this by checking the value of 'screen_size' before memset_io().

The Linux kernel CVE team has assigned CVE-2022-50101 to this issue.


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

	Issue introduced in 2.6.22 with commit 558b7bd86c32978648cda5deb5c758d77ef0c165 and fixed in 4.14.291 with commit 73280a184aa2e1a625ce54ce761042955cc79cd0
	Issue introduced in 2.6.22 with commit 558b7bd86c32978648cda5deb5c758d77ef0c165 and fixed in 4.19.256 with commit 52ad9bfeb8a0e62de30de6d39e8a49a72dd78150
	Issue introduced in 2.6.22 with commit 558b7bd86c32978648cda5deb5c758d77ef0c165 and fixed in 5.4.211 with commit d71528ccdc7ae8d7500d414091d27805c51407a2
	Issue introduced in 2.6.22 with commit 558b7bd86c32978648cda5deb5c758d77ef0c165 and fixed in 5.10.137 with commit bd8269e57621e5b38cc0b4bd2fa02e85c9f2a441
	Issue introduced in 2.6.22 with commit 558b7bd86c32978648cda5deb5c758d77ef0c165 and fixed in 5.15.61 with commit 4a3cef1eaced13ba9b55381d46bfad937a3dac2c
	Issue introduced in 2.6.22 with commit 558b7bd86c32978648cda5deb5c758d77ef0c165 and fixed in 5.18.18 with commit b17caec5127bba6f90af92bcc85871df54548ac0
	Issue introduced in 2.6.22 with commit 558b7bd86c32978648cda5deb5c758d77ef0c165 and fixed in 5.19.2 with commit c7a3f41e4b133d4dd25bc996b69039b19a34d69d
	Issue introduced in 2.6.22 with commit 558b7bd86c32978648cda5deb5c758d77ef0c165 and fixed in 6.0 with commit ec0754c60217248fa77cc9005d66b2b55200ac06

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-2022-50101
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/video/fbdev/vt8623fb.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/73280a184aa2e1a625ce54ce761042955cc79cd0
	https://git.kernel.org/stable/c/52ad9bfeb8a0e62de30de6d39e8a49a72dd78150
	https://git.kernel.org/stable/c/d71528ccdc7ae8d7500d414091d27805c51407a2
	https://git.kernel.org/stable/c/bd8269e57621e5b38cc0b4bd2fa02e85c9f2a441
	https://git.kernel.org/stable/c/4a3cef1eaced13ba9b55381d46bfad937a3dac2c
	https://git.kernel.org/stable/c/b17caec5127bba6f90af92bcc85871df54548ac0
	https://git.kernel.org/stable/c/c7a3f41e4b133d4dd25bc996b69039b19a34d69d
	https://git.kernel.org/stable/c/ec0754c60217248fa77cc9005d66b2b55200ac06