CVE-2023-53491

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

start_kernel: Add __nostackprotector 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 nostackprotector but GCC did not. This was fixed in gcc-11. Now that the function attribute is available, let's start using it.

Callers of bootinitstackcanary 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 bootinitstackcanary. This will lead to a call to __stackchkfail() then panic.