Messages in this thread Patch in this message | | | From | Kees Cook <> | Subject | [PATCH] kasan: test: Silence allocation warnings from GCC 12 | Date | Sun, 13 Feb 2022 10:32:32 -0800 |
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GCC 12 is able to see more problems with allocation sizes at compile time, so these must be silenced so the runtime checks will still be available. Use OPTIMIZER_HIDE_VAR() to silence the new warnings:
lib/test_kasan.c: In function 'ksize_uaf': lib/test_kasan.c:781:61: warning: array subscript 120 is outside array bounds of 'void[120]' [-Warray-bounds] 781 | KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]); | ~~~~~~~~~~~~~~~~~~~~~~^~~~~~ lib/test_kasan.c:96:9: note: in definition of macro 'KUNIT_EXPECT_KASAN_FAIL' 96 | expression; \ | ^~~~~~~~~~ In function 'kmalloc', inlined from 'ksize_uaf' at lib/test_kasan.c:775:8: ./include/linux/slab.h:581:24: note: at offset 120 into object of size 120 allocated by 'kmem_cache_alloc_trace' 581 | return kmem_cache_alloc_trace( | ^~~~~~~~~~~~~~~~~~~~~~~ 582 | kmalloc_caches[kmalloc_type(flags)][index], | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 583 | flags, size); | ~~~~~~~~~~~~
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> --- lib/test_kasan.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/lib/test_kasan.c b/lib/test_kasan.c index 26a5c9007653..a19b3d608e3e 100644 --- a/lib/test_kasan.c +++ b/lib/test_kasan.c @@ -124,6 +124,7 @@ static void kmalloc_oob_right(struct kunit *test) ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + OPTIMIZER_HIDE_VAR(ptr); /* * An unaligned access past the requested kmalloc size. @@ -185,6 +186,7 @@ static void kmalloc_pagealloc_oob_right(struct kunit *test) ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + OPTIMIZER_HIDE_VAR(ptr); KUNIT_EXPECT_KASAN_FAIL(test, ptr[size + OOB_TAG_OFF] = 0); kfree(ptr); @@ -265,6 +267,7 @@ static void kmalloc_large_oob_right(struct kunit *test) ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + OPTIMIZER_HIDE_VAR(ptr); KUNIT_EXPECT_KASAN_FAIL(test, ptr[size] = 0); kfree(ptr); } @@ -748,6 +751,7 @@ static void ksize_unpoisons_memory(struct kunit *test) ptr = kmalloc(size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); + OPTIMIZER_HIDE_VAR(ptr); real_size = ksize(ptr); /* This access shouldn't trigger a KASAN report. */ -- 2.30.2
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