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2024-04-03ubsan: fix unused variable warning in test moduleArnd Bergmann
This is one of the drivers with an unused variable that is marked 'const'. Adding a __used annotation here avoids the warning and lets us enable the option by default: lib/test_ubsan.c:137:28: error: unused variable 'skip_ubsan_array' [-Werror,-Wunused-const-variable] Fixes: 4a26f49b7b3d ("ubsan: expand tests and reporting") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Link: https://lore.kernel.org/r/20240403080702.3509288-3-arnd@kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
2024-02-20ubsan: Reintroduce signed overflow sanitizerKees Cook
In order to mitigate unexpected signed wrap-around[1], bring back the signed integer overflow sanitizer. It was removed in commit 6aaa31aeb9cf ("ubsan: remove overflow checks") because it was effectively a no-op when combined with -fno-strict-overflow (which correctly changes signed overflow from being "undefined" to being explicitly "wrap around"). Compilers are adjusting their sanitizers to trap wrap-around and to detecting common code patterns that should not be instrumented (e.g. "var + offset < var"). Prepare for this and explicitly rename the option from "OVERFLOW" to "WRAP" to more accurately describe the behavior. To annotate intentional wrap-around arithmetic, the helpers wrapping_add/sub/mul_wrap() can be used for individual statements. At the function level, the __signed_wrap attribute can be used to mark an entire function as expecting its signed arithmetic to wrap around. For a single object file the Makefile can use "UBSAN_SIGNED_WRAP_target.o := n" to mark it as wrapping, and for an entire directory, "UBSAN_SIGNED_WRAP := n" can be used. Additionally keep these disabled under CONFIG_COMPILE_TEST for now. Link: https://github.com/KSPP/linux/issues/26 [1] Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Hao Luo <haoluo@google.com> Reviewed-by: Marco Elver <elver@google.com> Reviewed-by: Justin Stitt <justinstitt@google.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2024-02-06ubsan: Silence W=1 warnings in self-testKees Cook
Silence a handful of W=1 warnings in the UBSan selftest, which set variables without using them. For example: lib/test_ubsan.c:101:6: warning: variable 'val1' set but not used [-Wunused-but-set-variable] 101 | int val1 = 10; | ^ Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202401310423.XpCIk6KO-lkp@intel.com/ Reviewed-by: Marco Elver <elver@google.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2022-01-20ubsan: remove CONFIG_UBSAN_OBJECT_SIZEKees Cook
The object-size sanitizer is redundant to -Warray-bounds, and inappropriately performs its checks at run-time when all information needed for the evaluation is available at compile-time, making it quite difficult to use: https://bugzilla.kernel.org/show_bug.cgi?id=214861 With -Warray-bounds almost enabled globally, it doesn't make sense to keep this around. Link: https://lkml.kernel.org/r/20211203235346.110809-1-keescook@chromium.org Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Marco Elver <elver@google.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-26ubsan: remove overflow checksAndrey Ryabinin
Since GCC 8.0 -fsanitize=signed-integer-overflow doesn't work with -fwrapv. -fwrapv makes signed overflows defines and GCC essentially disables ubsan checks. On GCC < 8.0 -fwrapv doesn't have influence on -fsanitize=signed-integer-overflow setting, so it kinda works but generates false-positves and violates uaccess rules: lib/iov_iter.o: warning: objtool: iovec_from_user()+0x22d: call to __ubsan_handle_add_overflow() with UACCESS enabled Disable signed overflow checks to avoid these problems. Remove unsigned overflow checks as well. Unsigned overflow appeared as side effect of commit cdf8a76fda4a ("ubsan: move cc-option tests into Kconfig"), but it never worked (kernel doesn't boot). And unsigned overflows are allowed by C standard, so it just pointless. Link: https://lkml.kernel.org/r/20210209232348.20510-1-ryabinin.a.a@gmail.com Signed-off-by: Andrey Ryabinin <ryabinin.a.a@gmail.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-12-15ubsan: expand tests and reportingKees Cook
Expand the UBSAN tests to include some additional UB cases. Notably the out-of-bounds enum loading appears not to work. Also include per-test reporting, including the relevant CONFIG_UBSAN... Kconfigs. Link: https://lkml.kernel.org/r/20201203004437.389959-8-keescook@chromium.org Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: George Popescu <georgepope@android.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Marco Elver <elver@google.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Nathan Chancellor <natechancellor@gmail.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Peter Oberparleiter <oberpar@linux.ibm.com> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-07lib/test_ubsan.c: VLA no longer used in kernelOlof Johansson
Since we now build with -Wvla, any use of VLA throws a warning. Including this test, so... maybe we should just remove the test? lib/test_ubsan.c: In function 'test_ubsan_vla_bound_not_positive': lib/test_ubsan.c:48:2: warning: ISO C90 forbids variable length array 'buf' [-Wvla] For the out-of-bounds test, switch to non-VLA setup. lib/test_ubsan.c: In function 'test_ubsan_out_of_bounds': lib/test_ubsan.c:64:2: warning: ISO C90 forbids variable length array 'arr' [-Wvla] Link: http://lkml.kernel.org/r/20190113183210.56154-1-olof@lixom.net Signed-off-by: Olof Johansson <olof@lixom.net> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Jinbum Park <jinb.park7@gmail.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11lib/test_ubsan.c: make test_ubsan_misaligned_access() staticColin Ian King
test_ubsan_misaligned_access() is local to the source and does not need to be in global scope, so make it static. Cleans up sparse warning: lib/test_ubsan.c:91:6: warning: symbol 'test_ubsan_misaligned_access' was not declared. Should it be static? Link: http://lkml.kernel.org/r/20180313103048.28513-1-colin.king@canonical.com Signed-off-by: Colin Ian King <colin.king@canonical.com> Cc: Jinbum Park <jinb.park7@gmail.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11lib: add testing module for UBSANJinbum Park
This is a test module for UBSAN. It triggers all undefined behaviors that linux supports now, and detect them. All test-cases have passed by compiling with gcc-5.5.0. If use gcc-4.9.x, misaligned, out-of-bounds, object-size-mismatch will not be detected. Because gcc-4.9.x doesn't support them. Link: http://lkml.kernel.org/r/20180309102247.GA2944@pjb1027-Latitude-E5410 Signed-off-by: Jinbum Park <jinb.park7@gmail.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>