Several other "dup"-style interfaces could use the __realloc_size()
attribute. (As a reminder to myself and others: "realloc" is used here
instead of "alloc" because the "alloc_size" attribute implies that the
memory contents are uninitialized. Since we're copying contents into the
resulting allocation, it must use "realloc_size" to avoid confusing the
compiler's optimization passes.)
Add KUnit test coverage where possible. (KUnit still does not have the
ability to manipulate userspace memory.)
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Link: https://lore.kernel.org/r/20240502145218.it.729-kees@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
The __alloc_size annotation for kmemdup() was getting disabled under
KUnit testing because the replaced fortify_panic macro implementation
was using "return NULL" as a way to survive the sanity checking. But
having the chance to return NULL invalidated __alloc_size, so kmemdup
was not passing the __builtin_dynamic_object_size() tests any more:
[23:26:18] [PASSED] fortify_test_alloc_size_kmalloc_const
[23:26:19] # fortify_test_alloc_size_kmalloc_dynamic: EXPECTATION FAILED at lib/fortify_kunit.c:265
[23:26:19] Expected __builtin_dynamic_object_size(p, 1) == expected, but
[23:26:19] __builtin_dynamic_object_size(p, 1) == -1 (0xffffffffffffffff)
[23:26:19] expected == 11 (0xb)
[23:26:19] __alloc_size() not working with __bdos on kmemdup("hello there", len, gfp)
[23:26:19] [FAILED] fortify_test_alloc_size_kmalloc_dynamic
Normal builds were not affected: __alloc_size continued to work there.
Use a zero-sized allocation instead, which allows __alloc_size to
behave.
Fixes: 4ce615e798 ("fortify: Provide KUnit counters for failure testing")
Fixes: fa4a3f86d4 ("fortify: Add KUnit tests for runtime overflows")
Link: https://lore.kernel.org/r/20240501232937.work.532-kees@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Add fortify tests for memcpy() and memmove(). This can use a similar
method to the fortify_panic() replacement, only we can do it for what
was the WARN_ONCE(), which can be redefined.
Since this is primarily testing the fortify behaviors of the memcpy()
and memmove() defenses, the tests for memcpy() and memmove() are
identical.
Link: https://lore.kernel.org/r/20240429194342.2421639-3-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
When running KUnit fortify tests, we're already doing precise tracking
of which warnings are getting hit. Don't fill the logs with WARNs unless
we've been explicitly built with DEBUG enabled.
Link: https://lore.kernel.org/r/20240429194342.2421639-2-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
The kv*() family of tests were accidentally freeing with vfree() instead
of kvfree(). Use kvfree() instead.
Fixes: 9124a26401 ("kunit/fortify: Validate __alloc_size attribute results")
Link: https://lore.kernel.org/r/20240425230619.work.299-kees@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Improve the reporting of buffer overflows under CONFIG_FORTIFY_SOURCE to
help accelerate debugging efforts. The calculations are all just sitting
in registers anyway, so pass them along to the function to be reported.
For example, before:
detected buffer overflow in memcpy
and after:
memcpy: detected buffer overflow: 4096 byte read of buffer size 1
Link: https://lore.kernel.org/r/20230407192717.636137-10-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
With fortify overflows able to be redirected, we can use KUnit to
exercise the overflow conditions. Add tests for every API covered by
CONFIG_FORTIFY_SOURCE, except for memset() and memcpy(), which are
special-cased for now.
Disable warnings in the Makefile since we're explicitly testing
known-bad string handling code patterns.
Note that this makes the LKDTM FORTIFY_STR* tests obsolete, but those
can be removed separately.
Signed-off-by: Kees Cook <keescook@chromium.org>
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>
In order for CI systems to notice all the skipped tests related to
CONFIG_FORTIFY_SOURCE, allow the FORTIFY_SOURCE KUnit tests to build
with or without CONFIG_FORTIFY_SOURCE.
Signed-off-by: Kees Cook <keescook@chromium.org>
Using struct root_device to create fake devices for tests is something
of a hack. The new struct kunit_device is meant for this purpose, so use
it instead.
Reviewed-by: Matti Vaittinen <mazziesaccount@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
This reverts commit a9dc8d0442.
The standard for KUnit is to not build tests at all when required
functionality is missing, rather than doing test "skip". Restore this
for the fortify tests, so that architectures without
CONFIG_ARCH_HAS_FORTIFY_SOURCE do not emit unsolvable warnings.
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Closes: https://lore.kernel.org/all/CAMuHMdUrxOEroHVUt7-mAnKSBjY=a-D3jr+XiAifuwv06Ob9Pw@mail.gmail.com
Signed-off-by: Kees Cook <keescook@chromium.org>
In order for CI systems to notice all the skipped tests related to
CONFIG_FORTIFY_SOURCE, allow the FORTIFY_SOURCE KUnit tests to build
with or without CONFIG_FORTIFY_SOURCE.
Signed-off-by: Kees Cook <keescook@chromium.org>
A much better "unknown size" string pointer is available directly from
struct test, so use that instead of a global that isn't shared with
modules.
Reported-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/lkml/YyCOHOchVuE/E7vS@dev-arch.thelio-3990X
Fixes: 875bfd5276 ("fortify: Add KUnit test for FORTIFY_SOURCE internals")
Cc: linux-hardening@vger.kernel.org
Build-tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Kees Cook