Bug 2373485 (CVE-2022-50102) - CVE-2022-50102 kernel: video: fbdev: arkfb: Fix a divide-by-zero bug in ark_set_pixclock()
Summary: CVE-2022-50102 kernel: video: fbdev: arkfb: Fix a divide-by-zero bug in ark_s...
Keywords:
Status: NEW
Alias: CVE-2022-50102
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-06-18 12:05 UTC by OSIDB Bzimport
Modified: 2025-11-25 15:29 UTC (History)
4 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2025-06-18 12:05:04 UTC
In the Linux kernel, the following vulnerability has been resolved:

video: fbdev: arkfb: Fix a divide-by-zero bug in ark_set_pixclock()

Since the user can control the arguments of the ioctl() from the user
space, under special arguments that may result in a divide-by-zero bug
in:
  drivers/video/fbdev/arkfb.c:784: ark_set_pixclock(info, (hdiv * info->var.pixclock) / hmul);
with hdiv=1, pixclock=1 and hmul=2 you end up with (1*1)/2 = (int) 0.
and then in:
  drivers/video/fbdev/arkfb.c:504: rv = dac_set_freq(par->dac, 0, 1000000000 / pixclock);
we'll get a division-by-zero.

The following log can reveal it:

divide error: 0000 [#1] PREEMPT SMP KASAN PTI
RIP: 0010:ark_set_pixclock drivers/video/fbdev/arkfb.c:504 [inline]
RIP: 0010:arkfb_set_par+0x10fc/0x24c0 drivers/video/fbdev/arkfb.c:784
Call Trace:
 fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1034
 do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1110
 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1189

Fix this by checking the argument of ark_set_pixclock() first.

Comment 1 Avinash Hanwate 2025-06-20 00:07:26 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025061804-CVE-2022-50102-9efe@gregkh/T


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