linux-stable.git/lib/overflow_kunit.c, branch v6.12

kunit/overflow: Fix UB in overflow_allocation_test

2024-08-15T16:24:55+00:00

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

kunit: add missing MODULE_DESCRIPTION() macros to lib/*.c

2024-06-25T05:25:06+00:00

make allmodconfig && make W=1 C=1 reports for lib/*kunit:
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/bitfield_kunit.o
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/checksum_kunit.o
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/cmdline_kunit.o
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/is_signed_type_kunit.o
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/overflow_kunit.o
WARNING: modpost: missing MODULE_DESCRIPTION() in lib/stackinit_kunit.o

Add the missing invocations of the MODULE_DESCRIPTION() macro.

Link: https://lkml.kernel.org/r/20240601-md-lib-kunit-tests-v1-1-4493fe0032b9@quicinc.com
Signed-off-by: Jeff Johnson 
Signed-off-by: Andrew Morton

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