kernel/linux.git/lib/test_ubsan.c, branch v6.6.131

ubsan: Fix panic from test_ubsan_out_of_bounds

2025-05-02T05:51:02+00:00

[ Upstream commit 9b044614be12d78d3a93767708b8d02fb7dfa9b0 ] Running lib_ubsan.ko on arm64 (without CONFIG_UBSAN_TRAP) panics the kernel: [ 31.616546] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: test_ubsan_out_of_bounds+0x158/0x158 [test_ubsan] [ 31.646817] CPU: 3 UID: 0 PID: 179 Comm: insmod Not tainted 6.15.0-rc2 #1 PREEMPT [ 31.648153] Hardware name: linux,dummy-virt (DT) [ 31.648970] Call trace: [ 31.649345] show_stack+0x18/0x24 (C) [ 31.650960] dump_stack_lvl+0x40/0x84 [ 31.651559] dump_stack+0x18/0x24 [ 31.652264] panic+0x138/0x3b4 [ 31.652812] __ktime_get_real_seconds+0x0/0x10 [ 31.653540] test_ubsan_load_invalid_value+0x0/0xa8 [test_ubsan] [ 31.654388] init_module+0x24/0xff4 [test_ubsan] [ 31.655077] do_one_initcall+0xd4/0x280 [ 31.655680] do_init_module+0x58/0x2b4 That happens because the test corrupts other data in the stack: 400: d5384108 mrs x8, sp_el0 404: f9426d08 ldr x8, [x8, #1240] 408: f85f83a9 ldur x9, [x29, #-8] 40c: eb09011f cmp x8, x9 410: 54000301 b.ne 470 // b.any As there is no guarantee the compiler will order the local variables as declared in the module: volatile char above[4] = { }; /* Protect surrounding memory. */ volatile int arr[4]; volatile char below[4] = { }; /* Protect surrounding memory. */ There is another problem where the out-of-bound index is 5 which is larger than the extra surrounding memory for protection. So, use a struct to enforce the ordering, and fix the index to be 4. Also, remove some of the volatiles and rely on OPTIMIZER_HIDE_VAR() Signed-off-by: Mostafa Saleh Link: https://lore.kernel.org/r/20250415203354.4109415-1-smostafa@google.com Signed-off-by: Kees Cook Signed-off-by: Sasha Levin

ubsan: remove CONFIG_UBSAN_OBJECT_SIZE

2022-01-20T06:52:55+00:00

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 Reviewed-by: Marco Elver Cc: Masahiro Yamada Cc: Michal Marek Cc: Nick Desaulniers Cc: Nathan Chancellor Cc: Andrey Ryabinin Cc: "Peter Zijlstra (Intel)" Cc: Stephen Rothwell Cc: Arnd Bergmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ubsan: remove overflow checks

2021-02-26T17:41:05+00:00

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 Acked-by: Peter Zijlstra (Intel) Cc: Josh Poimboeuf Cc: Randy Dunlap Cc: Stephen Rothwell Cc: Dmitry Vyukov Cc: Kees Cook Cc: Alexander Viro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ubsan: expand tests and reporting

2020-12-16T06:46:19+00:00

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 Cc: Andrey Ryabinin Cc: Ard Biesheuvel Cc: Arnd Bergmann Cc: Dmitry Vyukov Cc: George Popescu Cc: Herbert Xu Cc: Linus Torvalds Cc: Marco Elver Cc: Masahiro Yamada Cc: Michal Marek Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Peter Oberparleiter Cc: Randy Dunlap Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/test_ubsan.c: VLA no longer used in kernel

2019-03-08T02:32:00+00:00

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 Acked-by: Dmitry Vyukov Cc: Colin Ian King Cc: Jinbum Park Cc: Andrey Ryabinin Cc: Kees Cook Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib/test_ubsan.c: make test_ubsan_misaligned_access() static

2018-04-11T17:28:35+00:00

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 Cc: Jinbum Park Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Kees Cook Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib: add testing module for UBSAN

2018-04-11T17:28:35+00:00

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 Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Kees Cook Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds