CVE-2022-50099

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

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

In the function arkfb_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:

[ 659.399066] BUG: unable to handle page fault for address: ffffc90003000000 [ 659.399077] #PF: supervisor write access in kernel mode [ 659.399079] #PF: error_code(0x0002) - not-present page [ 659.399094] RIP: 0010:memset_orig+0x33/0xb0 [ 659.399116] Call Trace: [ 659.399122] arkfb_set_par+0x143f/0x24c0 [ 659.399130] fb_set_var+0x604/0xeb0 [ 659.399161] do_fb_ioctl+0x234/0x670 [ 659.399189] fb_ioctl+0xdd/0x130

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

This vulnerability carries no impact on supported Red Hat products because the legacy ARK Logic framebuffer driver is not enabled in default or optional kernel builds. The underlying flaw stems from insufficient bounds checking when handling user-provided display parameters, which can lead to an invalid kernel memory write. Because Red Hat kernels do not compile or distribute this legacy driver, enterprise installations are not affected.