> CVE-2022-22252: Huawei HWLog Vmalloc Use-After-Free

In this advisory we are disclosing a vulnerability in the Huawei log device that allows any unprivileged process to disclose sensitive information from the kernel. Huawei kernels are shipped with custom log devices (/dev/hwlog_dubai, /dev/hwlog_exception and /dev/hwlog_jank) that facilitate better system diagnostics through a series of ioctl calls. One of these diagnostics module is referred to as zrhung, and it provides information and configuration options to monitor hung processes. The implementation of the config set ioctl contains a race condition vulnerability that allows an attacker to free the underlying buffer that holds the configuration data. Consecutive config get ioctl calls use the dangling pointers to read and disclose, potentially sensitive, dynamically allocated kernel data.