kernel/linux.git/lib/overflow_kunit.c, branch v6.6.132

kunit/overflow: Fix UB in overflow_allocation_test

2025-04-10T12:37:42+00:00

commit 92e9bac18124682c4b99ede9ee3bcdd68f121e92 upstream. The 'device_name' array doesn't exist out of the 'overflow_allocation_test' function scope. However, it is being used as a driver name when calling 'kunit_driver_create' from 'kunit_device_register'. It produces the kernel panic with KASAN enabled. Since this variable is used in one place only, remove it and pass the device name into kunit_device_register directly as an ascii string. Signed-off-by: Ivan Orlov Reviewed-by: David Gow Link: https://lore.kernel.org/r/20240815000431.401869-1-ivan.orlov0322@gmail.com Signed-off-by: Kees Cook Signed-off-by: Jianqi Ren Signed-off-by: He Zhe Signed-off-by: Greg Kroah-Hartman

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

lib: overflow: update reference to kunit-tool

2022-09-30T19:21:14+00:00

Replace URL with an updated path to the full Documentation page Signed-off-by: Tales Aparecida Reviewed-by: Kees Cook Reviewed-by: David Gow Signed-off-by: Shuah Khan

overflow: Split up kunit tests for smaller stack frames

2022-09-07T23:37:26+00:00

Under some pathological 32-bit configs, the shift overflow KUnit tests create huge stack frames. Split up the function to avoid this, separating by rough shift overflow cases. Cc: Rasmus Villemoes Cc: Daniel Latypov Cc: Vitor Massaru Iha Cc: "Gustavo A. R. Silva" Cc: Nick Desaulniers Reported-by: kernel test robot Link: https://lore.kernel.org/lkml/202208301850.iuv9VwA8-lkp@intel.com Acked-by: Daniel Latypov Signed-off-by: Kees Cook

overflow: Allow mixed type arguments

2022-09-07T23:37:14+00:00

When the check_[op]_overflow() helpers were introduced, all arguments were required to be the same type to make the fallback macros simpler. However, now that the fallback macros have been removed[1], it is fine to allow mixed types, which makes using the helpers much more useful, as they can be used to test for type-based overflows (e.g. adding two large ints but storing into a u8), as would be handy in the drm core[2]. Remove the restriction, and add additional self-tests that exercise some of the mixed-type overflow cases, and double-check for accidental macro side-effects. [1] https://git.kernel.org/linus/4eb6bd55cfb22ffc20652732340c4962f3ac9a91 [2] https://lore.kernel.org/lkml/20220824084514.2261614-2-gwan-gyeong.mun@intel.com Cc: Rasmus Villemoes Cc: Gwan-gyeong Mun Cc: "Gustavo A. R. Silva" Cc: Nick Desaulniers Cc: linux-hardening@vger.kernel.org Reviewed-by: Andrzej Hajda Reviewed-by: Gwan-gyeong Mun Tested-by: Gwan-gyeong Mun Signed-off-by: Kees Cook

lib: overflow: Do not define 64-bit tests on 32-bit

2022-07-02T00:39:49+00:00

The 64-bit overflow tests will trigger 64-bit division on 32-bit hosts, which is not currently used anywhere in the kernel, and tickles bugs in at least Clang 13 and earlier: https://github.com/ClangBuiltLinux/linux/issues/1636 In reality, there shouldn't be a reason to not build the 64-bit test cases on 32-bit systems, so these #ifdefs can be removed once the minimum Clang version reaches 13. In the meantime, silence W=1 warnings given by the current code: ../lib/overflow_kunit.c:191:19: warning: 's64_tests' defined but not used [-Wunused-const-variable=] 191 | DEFINE_TEST_ARRAY(s64) = { | ^~~ ../lib/overflow_kunit.c:24:11: note: in definition of macro 'DEFINE_TEST_ARRAY' 24 | } t ## _tests[] | ^ ../lib/overflow_kunit.c:94:19: warning: 'u64_tests' defined but not used [-Wunused-const-variable=] 94 | DEFINE_TEST_ARRAY(u64) = { | ^~~ ../lib/overflow_kunit.c:24:11: note: in definition of macro 'DEFINE_TEST_ARRAY' 24 | } t ## _tests[] | ^ Reported-by: kernel test robot Link: https://lore.kernel.org/lkml/202205110324.7GrtxG8u-lkp@intel.com Fixes: 455a35a6cdb6 ("lib: add runtime test of check_*_overflow functions") Cc: Rasmus Villemoes Cc: Nick Desaulniers Cc: Vitor Massaru Iha Cc: "Gustavo A. R. Silva" Tested-by: Daniel Latypov Link: https://lore.kernel.org/lkml/CAGS_qxokQAjQRip2vPi80toW7hmBnXf=KMTNT51B1wuDqSZuVQ@mail.gmail.com Signed-off-by: Kees Cook