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…
Impact
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
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Linux | Linux Kernel | before 4.9.327 from 4.10 before 4.14.292 from 4.15 before 4.19.257 from 4.20 before 5.4.212 from 5.5 before 5.10.141 from 5.11 before 5.15.65 |
Weakness classification
References
- NVD record
- CVE.org record
- https://git.kernel.org/stable/c/0f1174f4972ea9fad6becf8881d71adca8e9ca91
- https://git.kernel.org/stable/c/19f953e7435644b81332dd632ba1b2d80b1e37af
- https://git.kernel.org/stable/c/34c3dea1189525cd533071ed5c176fc4ea8d982b
- https://git.kernel.org/stable/c/3ec326a6a0d4667585ca595f438c7293e5ced7c4
- https://git.kernel.org/stable/c/7d9591b32a9092fc6391a316b56e8016c6181c3d
- https://git.kernel.org/stable/c/7f88cdfea8d7f4dbaf423d808241403b2bb945e4
- https://git.kernel.org/stable/c/8fc778ee2fb2853f7a3531fa7273349640d8e4e9
- https://git.kernel.org/stable/c/cb4bb011a683532841344ca7f281b5e04389b4f8