CVE-2022-49425

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

f2fs: fix dereference of stale list iterator after loop body

The list iterator variable will be a bogus pointer if no break was hit. Dereferencing it (cur->page in this case) could load an out-of-bounds/undefined value making it unsafe to use that in the comparision to determine if the specific element was found.

Since 'cur->page' can be out-ouf-bounds it cannot be guaranteed that by chance (or intention of an attacker) it matches the value of 'page' even though the correct element was not found.

This is fixed by using a separate list iterator variable for the loop and only setting the original variable if a suitable element was found. Then determing if the element was found is simply checking if the variable is set.

This vulnerability does not affect Red Hat Enterprise Linux as support for the Flash-Friendly File System (F2FS) is not enabled in supported enterprise kernels. The upstream issue stems from improper handling of stale list iterators within the F2FS segment allocation logic, potentially allowing a local user with filesystem mounting capabilities to cause out-of-bounds memory reads or denial of service. Because Red Hat does not compile or distribute the F2FS kernel module, default enterprise installations are not exposed to this flaw.