CVE-2022-49640

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

sysctl: Fix data races in proc_douintvec_minmax().

A sysctl variable is accessed concurrently, and there is always a chance of data-race. So, all readers and writers need some basic protection to avoid load/store-tearing.

This patch changes proc_douintvec_minmax() to use READ_ONCE() and WRITE_ONCE() internally to fix data-races on the sysctl side. For now, proc_douintvec_minmax() itself is tolerant to a data-race, but we still need to add annotations on the other subsystem's side.

The bug can lead to incorrect numerical value being read with sysctl for some specific cases if race condition happened (when both modifying this value and reading). The security impact is limited, because no known vectors of attack and no actual kernel panic or other fail. The bug actual only for Red Hat Enterprise Linux 8 and already fixed in Red Hat Enterprise Linux 9 and later versions. The bug could happen only for the case of reading (with in parallel modifying) of specific type of values "a vector of unsigned ints with min/max values" and the max impact could be incorrect values being read.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.