Andreas Kling 4188373020 Kernel: Fix TOCTOU in syscall entry region validation ...

We were doing stack and syscall-origin region validations before
taking the big process lock. There was a window of time where those
regions could then be unmapped/remapped by another thread before we
proceed with our syscall.

This patch closes that window, and makes sys$get_stack_bounds() rely
on the fact that we now know the userspace stack pointer to be valid.

Thanks to @BenWiederhake for spotting this! :^)

2021-02-14 11:47:14 +01:00

7.8 KiB

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