CVE-2022-49978
In the Linux kernel, the following vulnerability has been resolved: fbdev: fb_pm2fb: Avoid potential divide by zero error In `do_fb_ioctl()` of fbmem.c, if cmd is FBIOPUT_VSCREENINFO, var will be copied from user, then go through `fb_set_var()` and…
Does this matter?
Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own.
Description
In the Linux kernel, the following vulnerability has been resolved: fbdev: fb_pm2fb: Avoid potential divide by zero error In `do_fb_ioctl()` of fbmem.c, if cmd is FBIOPUT_VSCREENINFO, var will be copied from user, then go through `fb_set_var()` and `info->fbops->fb_check_var()` which could may be `pm2fb_check_var()`. Along the path, `var->pixclock` won't be modified. This function checks whether reciprocal of `var->pixclock` is too high. If `var->pixclock` is zero, there will be a divide by zero error. So, it is necessary to check whether denominator is zero to avoid crash. As this bug is found by Syzkaller, logs are listed below. divide error in pm2fb_check_var Call Trace: <TASK> fb_set_var+0x367/0xeb0 drivers/video/fbdev/core/fbmem.c:1015 do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1110 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1189
- CVSS 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.23% probability · 14th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-369
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/0f1174f4972ea9fad6becf8881d71adca8e9ca91Patch
- https://git.kernel.org/stable/c/19f953e7435644b81332dd632ba1b2d80b1e37afPatch
- https://git.kernel.org/stable/c/34c3dea1189525cd533071ed5c176fc4ea8d982bPatch
- https://git.kernel.org/stable/c/3ec326a6a0d4667585ca595f438c7293e5ced7c4Patch
- https://git.kernel.org/stable/c/7d9591b32a9092fc6391a316b56e8016c6181c3dPatch
- https://git.kernel.org/stable/c/7f88cdfea8d7f4dbaf423d808241403b2bb945e4Patch
- https://git.kernel.org/stable/c/8fc778ee2fb2853f7a3531fa7273349640d8e4e9Patch
- https://git.kernel.org/stable/c/cb4bb011a683532841344ca7f281b5e04389b4f8Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.