| Message ID | 20211020193807.40684-1-keescook@chromium.org (mailing list archive) |
|---|---|
| State | Superseded |
| Commit | cd38dec743ae53023e018684ac0dd62750fee980 |
| Delegated to: | Kees Cook |
| Headers | show |
| Series | kasan: test: Consolidate workarounds for unwanted __alloc_size() protection | expand |
On Wed, Oct 20, 2021 at 9:38 PM Kees Cook <keescook@chromium.org> wrote: > > This fixes kasan-test-use-underlying-string-helpers.patch to avoid needing > new helpers. As done in kasan-test-bypass-__alloc_size-checks.patch, > just use OPTIMIZER_HIDE_VAR(). Additionally converts a use of > "volatile", which was trying to work around similar detection. > > Cc: Arnd Bergmann <arnd@arndb.de> > Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> > Cc: Alexander Potapenko <glider@google.com> > Cc: Andrey Konovalov <andreyknvl@gmail.com> > Cc: Dmitry Vyukov <dvyukov@google.com> > Cc: kasan-dev@googlegroups.com > Signed-off-by: Kees Cook <keescook@chromium.org> Yes, that's much better than my version Acked-by: Arnd Bergmann <arnd@arndb.de>
On Wed, 20 Oct 2021 12:38:07 -0700 Kees Cook <keescook@chromium.org> wrote: > This fixes kasan-test-use-underlying-string-helpers.patch to avoid needing > new helpers. As done in kasan-test-bypass-__alloc_size-checks.patch, > just use OPTIMIZER_HIDE_VAR(). Additionally converts a use of > "volatile", which was trying to work around similar detection. > > ... > > Can you please collapse this into your series? Folding it into something else is messy, due to dependencies and ordering/timing issues. I queued it as a standalone thing.
diff --git a/lib/test_kasan.c b/lib/test_kasan.c index 318fc612e7e7..96a1f085b460 100644 --- a/lib/test_kasan.c +++ b/lib/test_kasan.c @@ -525,12 +525,13 @@ static void kmalloc_memmove_invalid_size(struct kunit *test) { char *ptr; size_t size = 64; - volatile size_t invalid_size = size; + size_t invalid_size = size; ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); memset((char *)ptr, 0, 64); + OPTIMIZER_HIDE_VAR(invalid_size); KUNIT_EXPECT_KASAN_FAIL(test, memmove((char *)ptr, (char *)ptr + 4, invalid_size)); kfree(ptr); @@ -852,21 +853,6 @@ static void kmem_cache_invalid_free(struct kunit *test) kmem_cache_destroy(cache); } -/* - * noinline wrappers to prevent the compiler from noticing the overflow - * at compile time rather than having kasan catch it. - */ -static noinline void *__kasan_memchr(const void *s, int c, size_t n) -{ - return memchr(s, c, n); -} - -static noinline int __kasan_memcmp(const void *s1, const void *s2, size_t n) -{ - return memcmp(s1, s2, n); -} - - static void kasan_memchr(struct kunit *test) { char *ptr; @@ -884,8 +870,9 @@ static void kasan_memchr(struct kunit *test) ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + OPTIMIZER_HIDE_VAR(size); KUNIT_EXPECT_KASAN_FAIL(test, - kasan_ptr_result = __kasan_memchr(ptr, '1', size + 1)); + kasan_ptr_result = memchr(ptr, '1', size + 1)); kfree(ptr); } @@ -909,8 +896,9 @@ static void kasan_memcmp(struct kunit *test) KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); memset(arr, 0, sizeof(arr)); + OPTIMIZER_HIDE_VAR(size); KUNIT_EXPECT_KASAN_FAIL(test, - kasan_int_result = __kasan_memcmp(ptr, arr, size+1)); + kasan_int_result = memcmp(ptr, arr, size+1)); kfree(ptr); }
This fixes kasan-test-use-underlying-string-helpers.patch to avoid needing new helpers. As done in kasan-test-bypass-__alloc_size-checks.patch, just use OPTIMIZER_HIDE_VAR(). Additionally converts a use of "volatile", which was trying to work around similar detection. Cc: Arnd Bergmann <arnd@arndb.de> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: kasan-dev@googlegroups.com Signed-off-by: Kees Cook <keescook@chromium.org> --- Hi Andrew, Can you please collapse this into your series? It's cleaner to use the same method everywhere in this file to avoid the compiler being smart. :) Thanks! -Kees --- lib/test_kasan.c | 24 ++++++------------------ 1 file changed, 6 insertions(+), 18 deletions(-)