CVE-2022-49978
fbdev: fb_pm2fb: Avoid potential divide by zero error
We use these services and cookies to improve your user experience. You may opt out if you wish, however, this may limit some features on this site.
Please see our statement on Data Privacy.
fbdev: fb_pm2fb: Avoid potential divide by zero error
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
Reserved 2025-06-18 | Published 2025-06-18 | Updated 2025-06-18 | Assigner Linuxgit.kernel.org/...c/0f1174f4972ea9fad6becf8881d71adca8e9ca91
git.kernel.org/...c/3ec326a6a0d4667585ca595f438c7293e5ced7c4
git.kernel.org/...c/7f88cdfea8d7f4dbaf423d808241403b2bb945e4
git.kernel.org/...c/7d9591b32a9092fc6391a316b56e8016c6181c3d
git.kernel.org/...c/8fc778ee2fb2853f7a3531fa7273349640d8e4e9
git.kernel.org/...c/34c3dea1189525cd533071ed5c176fc4ea8d982b
git.kernel.org/...c/cb4bb011a683532841344ca7f281b5e04389b4f8
git.kernel.org/...c/19f953e7435644b81332dd632ba1b2d80b1e37af
Support options
