CVE-2022-50097

In the Linux kernel, the following vulnerability has been resolved:

video: fbdev: s3fb: Check the size of screen before memset_io()

In the function s3fb_set_par(), the value of 'screen_size' is calculated by the user input. If the user provides the improper value, the value of 'screen_size' may larger than 'info->screen_size', which may cause the following bug:

[ 54.083733] BUG: unable to handle page fault for address: ffffc90003000000 [ 54.083742] #PF: supervisor write access in kernel mode [ 54.083744] #PF: error_code(0x0002) - not-present page [ 54.083760] RIP: 0010:memset_orig+0x33/0xb0 [ 54.083782] Call Trace: [ 54.083788] s3fb_set_par+0x1ec6/0x4040 [ 54.083806] fb_set_var+0x604/0xeb0 [ 54.083836] do_fb_ioctl+0x234/0x670

Fix the this by checking the value of 'screen_size' before memset_io().

This vulnerability does not affect Red Hat Enterprise Linux or other Red Hat products because support for the legacy S3 framebuffer driver is not enabled in supported kernel configurations. The flaw requires specific obsolete graphics hardware driver code that is excluded from Red Hat distributions. Consequently, standard deployments are not exposed to this risk.