linux-stable.git/lib/overflow_kunit.c, branch v6.10

kunit/overflow: Adjust for __counted_by with DEFINE_RAW_FLEX()

2024-06-10T19:00:04+00:00

When a flexible array structure has a __counted_by annotation, its use
with DEFINE_RAW_FLEX() will result in the count being zero-initialized.
This is expected since one doesn't want to use RAW with a counted_by
struct. Adjust the tests to check for the condition and for compiler
support.

Reported-by: Christian Schrefl 
Closes: https://lore.kernel.org/all/0bfc6b38-8bc5-4971-b6fb-dc642a73fbfe@gmail.com/
Suggested-by: Nathan Chancellor 
Reviewed-by: Nathan Chancellor 
Link: https://lore.kernel.org/r/20240610182301.work.272-kees@kernel.org
Tested-by: Christian Schrefl 
Reviewed-by: Christian Schrefl 
Signed-off-by: Kees Cook

overflow: Change DEFINE_FLEX to take __counted_by member

2024-03-22T23:25:31+00:00

The norm should be flexible array structures with __counted_by
annotations, so DEFINE_FLEX() is updated to expect that. Rename
the non-annotated version to DEFINE_RAW_FLEX(), and update the
few existing users. Additionally add selftests for the macros.

Reviewed-by: Gustavo A. R. Silva 
Link: https://lore.kernel.org/r/20240306235128.it.933-kees@kernel.org
Reviewed-by: Przemek Kitszel 
Signed-off-by: Kees Cook

overflow: Introduce wrapping_assign_add() and wrapping_assign_sub()

2024-02-29T21:38:01+00:00

This allows replacements of the idioms "var += offset" and "var -=
offset" with the wrapping_assign_add() and wrapping_assign_sub() helpers
respectively. They will avoid wrap-around sanitizer instrumentation.

Add to the selftests to validate behavior and lack of side-effects.

Reviewed-by: Marco Elver 
Acked-by: Mark Rutland 
Signed-off-by: Kees Cook

overflow: Introduce wrapping_add(), wrapping_sub(), and wrapping_mul()

2024-02-29T21:38:01+00:00

Provide helpers that will perform wrapping addition, subtraction, or
multiplication without tripping the arithmetic wrap-around sanitizers. The
first argument is the type under which the wrap-around should happen
with. In other words, these two calls will get very different results:

	wrapping_mul(int, 50, 50) == 2500
	wrapping_mul(u8,  50, 50) ==  196

Add to the selftests to validate behavior and lack of side-effects.

Reviewed-by: Gustavo A. R. Silva 
Reviewed-by: Marco Elver 
Acked-by: Mark Rutland 
Signed-off-by: Kees Cook

overflow: Replace fake root_device with kunit_device

2023-12-18T20:28:08+00:00

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 
Acked-by: Kees Cook 
Signed-off-by: David Gow 
Signed-off-by: Shuah Khan

overflow: Add struct_size_t() helper

2023-05-26T20:52:19+00:00

While struct_size() is normally used in situations where the structure
type already has a pointer instance, there are places where no variable
is available. In the past, this has been worked around by using a typed
NULL first argument, but this is a bit ugly. Add a helper to do this,
and replace the handful of instances of the code pattern with it.

Instances were found with this Coccinelle script:

@struct_size_t@
identifier STRUCT, MEMBER;
expression COUNT;
@@

-       struct_size((struct STRUCT *)\(0\|NULL\),
+       struct_size_t(struct STRUCT,
                MEMBER, COUNT)

Suggested-by: Christoph Hellwig 
Cc: Jesse Brandeburg 
Cc: Tony Nguyen 
Cc: "David S. Miller" 
Cc: Eric Dumazet 
Cc: Paolo Abeni 
Cc: James Smart 
Cc: Keith Busch 
Cc: Jens Axboe 
Cc: Sagi Grimberg 
Cc: HighPoint Linux Team 
Cc: "James E.J. Bottomley" 
Cc: "Martin K. Petersen" 
Cc: Kashyap Desai 
Cc: Sumit Saxena 
Cc: Shivasharan S 
Cc: Don Brace 
Cc: "Darrick J. Wong" 
Cc: Dave Chinner 
Cc: Guo Xuenan 
Cc: Gwan-gyeong Mun 
Cc: Nick Desaulniers 
Cc: Daniel Latypov 
Cc: kernel test robot 
Cc: intel-wired-lan@lists.osuosl.org
Cc: netdev@vger.kernel.org
Cc: linux-nvme@lists.infradead.org
Cc: linux-scsi@vger.kernel.org
Cc: megaraidlinux.pdl@broadcom.com
Cc: storagedev@microchip.com
Cc: linux-xfs@vger.kernel.org
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook 
Acked-by: Martin K. Petersen 
Reviewed-by: Darrick J. Wong 
Reviewed-by: Gustavo A. R. Silva 
Reviewed-by: Christoph Hellwig 
Acked-by: Jakub Kicinski 
Reviewed-by: Alexander Lobakin 
Link: https://lore.kernel.org/r/20230522211810.never.421-kees@kernel.org

overflow: Introduce overflows_type() and castable_to_type()

2022-11-02T19:39:27+00:00

Implement a robust overflows_type() macro to test if a variable or
constant value would overflow another variable or type. This can be
used as a constant expression for static_assert() (which requires a
constant expression[1][2]) when used on constant values. This must be
constructed manually, since __builtin_add_overflow() does not produce
a constant expression[3].

Additionally adds castable_to_type(), similar to __same_type(), but for
checking if a constant value would overflow if cast to a given type.

Add unit tests for overflows_type(), __same_type(), and castable_to_type()
to the existing KUnit "overflow" test:

[16:03:33] ================== overflow (21 subtests) ==================
...
[16:03:33] [PASSED] overflows_type_test
[16:03:33] [PASSED] same_type_test
[16:03:33] [PASSED] castable_to_type_test
[16:03:33] ==================== [PASSED] overflow =====================
[16:03:33] ============================================================
[16:03:33] Testing complete. Ran 21 tests: passed: 21
[16:03:33] Elapsed time: 24.022s total, 0.002s configuring, 22.598s building, 0.767s running

[1] https://en.cppreference.com/w/c/language/_Static_assert
[2] C11 standard (ISO/IEC 9899:2011): 6.7.10 Static assertions
[3] https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html
    6.56 Built-in Functions to Perform Arithmetic with Overflow Checking
    Built-in Function: bool __builtin_add_overflow (type1 a, type2 b,

Cc: Luc Van Oostenryck 
Cc: Nathan Chancellor 
Cc: Nick Desaulniers 
Cc: Tom Rix 
Cc: Daniel Latypov 
Cc: Vitor Massaru Iha 
Cc: "Gustavo A. R. Silva" 
Cc: Jani Nikula 
Cc: Mauro Carvalho Chehab 
Cc: linux-hardening@vger.kernel.org
Cc: llvm@lists.linux.dev
Co-developed-by: Gwan-gyeong Mun 
Signed-off-by: Gwan-gyeong Mun 
Signed-off-by: Kees Cook 
Link: https://lore.kernel.org/r/20221024201125.1416422-1-gwan-gyeong.mun@intel.com

overflow: Refactor test skips for Clang-specific issues

2022-10-25T21:57:42+00:00

Convert test exclusion into test skipping. This brings the logic for
why a test is being skipped into the test itself, instead of having to
spread ifdefs around the code. This will make cleanup easier as minimum
tests get raised. Drop __maybe_unused so missed tests will be noticed
again and clean up whitespace.

For example, clang-11 on i386:

[15:52:32] ================== overflow (18 subtests) ==================
[15:52:32] [PASSED] u8_u8__u8_overflow_test
[15:52:32] [PASSED] s8_s8__s8_overflow_test
[15:52:32] [PASSED] u16_u16__u16_overflow_test
[15:52:32] [PASSED] s16_s16__s16_overflow_test
[15:52:32] [PASSED] u32_u32__u32_overflow_test
[15:52:32] [PASSED] s32_s32__s32_overflow_test
[15:52:32] [SKIPPED] u64_u64__u64_overflow_test
[15:52:32] [SKIPPED] s64_s64__s64_overflow_test
[15:52:32] [SKIPPED] u32_u32__int_overflow_test
[15:52:32] [PASSED] u32_u32__u8_overflow_test
[15:52:32] [PASSED] u8_u8__int_overflow_test
[15:52:32] [PASSED] int_int__u8_overflow_test
[15:52:32] [PASSED] shift_sane_test
[15:52:32] [PASSED] shift_overflow_test
[15:52:32] [PASSED] shift_truncate_test
[15:52:32] [PASSED] shift_nonsense_test
[15:52:32] [PASSED] overflow_allocation_test
[15:52:32] [PASSED] overflow_size_helpers_test
[15:52:32] ==================== [PASSED] overflow =====================
[15:52:32] ============================================================
[15:52:32] Testing complete. Ran 18 tests: passed: 15, skipped: 3

Cc: Nick Desaulniers 
Cc: Nathan Chancellor 
Cc: Tom Rix 
Cc: Daniel Latypov 
Cc: "Gustavo A. R. Silva" 
Cc: Gwan-gyeong Mun 
Cc: llvm@lists.linux.dev
Signed-off-by: Kees Cook 
Reviewed-by: Nick Desaulniers 
Tested-by: Nick Desaulniers 
Link: https://lore.kernel.org/r/20221006230017.1833458-1-keescook@chromium.org

overflow: disable failing tests for older clang versions

2022-10-25T21:57:42+00:00

Building the overflow kunit tests with clang-11 fails with:

$ ./tools/testing/kunit/kunit.py run --arch=arm --make_options LLVM=1 \
overflow
...
ld.lld: error: undefined symbol: __mulodi4
...

Clang 11 and earlier generate unwanted libcalls for signed output,
unsigned input.

Disable these tests for now, but should these become used in the kernel
we might consider that as justification for dropping clang-11 support.
Keep the clang-11 build alive a little bit longer.

Avoid -Wunused-function warnings via __maybe_unused. To test W=1:

$ make LLVM=1 -j128 defconfig
$ ./scripts/config -e KUNIT -e KUNIT_ALL
$ make LLVM=1 -j128 olddefconfig lib/overflow_kunit.o W=1

Link: https://github.com/ClangBuiltLinux/linux/issues/1711
Link: https://github.com/llvm/llvm-project/commit/3203143f1356a4e4e3ada231156fc6da6e1a9f9d
Reported-by: Nathan Chancellor 
Signed-off-by: Nick Desaulniers 
Signed-off-by: Kees Cook 
Link: https://lore.kernel.org/r/20221006171751.3444575-1-ndesaulniers@google.com

Merge tag 'linux-kselftest-kunit-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

2022-10-06T19:57:55+00:00

Pull KUnit updates from Shuah Khan:
 "Several documentation fixes, UML related cleanups, and a feature to
  enable/disable KUnit tests

  This includes the change to rename all_test_uml.config, and use it for
  '--alltests'. Note: if anyone was using all_tests_uml.config, this
  change breaks them.

  This change simplifies the usage and eliminates the need to type:

     --kunitconfig=tools/testing/kunit/configs/all_tests_uml.config

  A simple workaround to create a symlink to the new name can solve the
  problem for anyone using all_tests_uml.config.

  all_tests_uml.config should work across ~all architectures"

* tag 'linux-kselftest-kunit-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  Documentation: Kunit: Use full path to .kunitconfig
  kunit: tool: rename all_test_uml.config, use it for --alltests
  kunit: tool: remove UML specific options from all_tests_uml.config
  lib: stackinit: update reference to kunit-tool
  lib: overflow: update reference to kunit-tool
  Documentation: KUnit: update links in the index page
  Documentation: KUnit: add intro to the getting-started page
  Documentation: KUnit: Reword start guide for selecting tests
  Documentation: KUnit: add note about mrproper in start.rst
  Documentation: KUnit: avoid repeating "kunit.py run" in start.rst
  Documentation: KUnit: remove duplicated docs for kunit_tool
  Documentation: Kunit: Add ref for other kinds of tests
  Documentation: KUnit: Fix non-uml anchor
  Documentation: Kunit: Fix inconsistent titles
  Documentation: kunit: fix trivial typo
  kunit: no longer call module_info(test, "Y") for kunit modules
  kunit: add kunit.enable to enable/disable KUnit test
  kunit: tool: make --raw_output=kunit (aka --raw_output) preserve leading spaces