lkdtm/stackleak: prevent unexpected stack usage

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The lkdtm_STACKLEAK_ERASING() test is instrumentable and runs with IRQs
unmasked, so it's possible for unrelated code to clobber the task stack
and/or manipulate current->lowest_stack while the test is running,
resulting in spurious failures.

The regular stackleak erasing code is non-instrumentable and runs with
IRQs masked, preventing similar issues.

Make the body of the test non-instrumentable, and run it with IRQs
masked, avoiding such spurious failures.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Popov <alex.popov@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220427173128.2603085-11-mark.rutland@arm.com

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Mark Rutland 2022-04-27 18:31:25 +01:00 • committed by Kees Cook

parent 72b61896f2

commit f03a50938d

1 changed files with 23 additions and 1 deletions

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drivers/misc/lkdtm/stackleak.c

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