fortify: Provide KUnit counters for failure testing

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The standard C string APIs were not designed to have a failure mode;
they were expected to always succeed without memory safety issues.
Normally, CONFIG_FORTIFY_SOURCE will use fortify_panic() to stop
processing, as truncating a read or write may provide an even worse
system state. However, this creates a problem for testing under things
like KUnit, which needs a way to survive failures.

When building with CONFIG_KUNIT, provide a failure path for all users
of fortify_panic, and track whether the failure was a read overflow or
a write overflow, for KUnit tests to examine. Inspired by similar logic
in the slab tests.

Signed-off-by: Kees Cook <keescook@chromium.org>

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This commit is contained in:

Kees Cook 2023-04-07 12:27:14 -07:00

parent 1a78f8cb5d

commit 4ce615e798

3 changed files with 66 additions and 20 deletions

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41

include/linux/fortify-string.h

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41

lib/fortify_kunit.c

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2

lib/string_helpers.c

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