Bug 2373525 (CVE-2022-50010) - CVE-2022-50010 kernel: video: fbdev: i740fb: Check the argument of i740_calc_vclk()
Summary: CVE-2022-50010 kernel: video: fbdev: i740fb: Check the argument of i740_calc_...
Keywords:
Status: NEW
Alias: CVE-2022-50010
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-06-18 12:06 UTC by OSIDB Bzimport
Modified: 2025-06-19 18:04 UTC (History)
4 users (show)

Fixed In Version:
Clone Of:
Environment:
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Description OSIDB Bzimport 2025-06-18 12:06:49 UTC
In the Linux kernel, the following vulnerability has been resolved:

video: fbdev: i740fb: Check the argument of i740_calc_vclk()

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.

If the user provides an improper 'pixclock' value that makes the argumet
of i740_calc_vclk() less than 'I740_RFREQ_FIX', it will cause a
divide-by-zero bug in:
    drivers/video/fbdev/i740fb.c:353 p_best = min(15, ilog2(I740_MAX_VCO_FREQ / (freq / I740_RFREQ_FIX)));

The following log can reveal it:

divide error: 0000 [#1] PREEMPT SMP KASAN PTI
RIP: 0010:i740_calc_vclk drivers/video/fbdev/i740fb.c:353 [inline]
RIP: 0010:i740fb_decode_var drivers/video/fbdev/i740fb.c:646 [inline]
RIP: 0010:i740fb_set_par+0x163f/0x3b70 drivers/video/fbdev/i740fb.c:742
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 i740_calc_vclk() first.

Comment 1 Avinash Hanwate 2025-06-19 17:54:16 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025061831-CVE-2022-50010-a0ff@gregkh/T


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