Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
fbdev: core: fbcvt: avoid division by 0 in fb_cvt_hperiod()
In fb_find_mode_cvt(), iff mode->refresh somehow happens to be 0x80000000, cvt.f_refresh will become 0 when multiplying it by 2 due to overflow. It’s then passed to fb_cvt_hperiod(), where it’s used as a divider – division by 0 will result in kernel oops. Add a sanity check for cvt.f_refresh to avoid such overflow…
Found by Linux Verification Center (linuxtesting.org) with the Svace static analysis tool.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 7 ELS , Oracle Linux 6 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- kernel @ 5.14.0 (+15 more)
In the Linux kernel, the following vulnerability has been resolved:
fbdev: core: fbcvt: avoid division by 0 in fb_cvt_hperiod()
In fb_find_mode_cvt(), iff mode->refresh somehow happens to be 0x80000000, cvt.f_refresh will become 0 when multiplying it by 2 due to overflow. It’s then passed to fb_cvt_hperiod(), where it’s used as a divider – division by 0 will result in kernel oops. Add a sanity check for cvt.f_refresh to avoid such overflow…
Found by Linux Verification Center (linuxtesting.org) with the Svace static analysis tool.