CVE-2023-53491

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

start_kernel: Add __no_stack_protector function attribute

Back during the discussion of commit a9a3ed1eff36 ("x86: Fix early boot crash on gcc-10, third try") we discussed the need for a function attribute to control the omission of stack protectors on a per-function basis; at the time Clang had support for no_stack_protector but GCC did not. This was fixed in gcc-11. Now that the function attribute is available, let's start using it.

Callers of boot_init_stack_canary need to use this function attribute unless they're compiled with -fno-stack-protector, otherwise the canary stored in the stack slot of the caller will differ upon the call to boot_init_stack_canary. This will lead to a call to __stack_chk_fail() then panic.

This vulnerability is rated as Moderate severity because it leads solely to a denial of service through an early boot crash without compromising data confidentiality or system integrity. The failure manifests during initial system startup when kernel stack canary mechanisms are initialized, meaning active runtime environments cannot be exploited remotely or by unprivileged local users. Standard enterprise deployments running production workloads are therefore unaffected unless encountering boot failures with impacted builds.

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.