From: Kees Cook keescook@chromium.org
[ Upstream commit aaf50b1969d7933a51ea421b11432a7fb90974e3 ]
GCC 12 continues to get smarter about array accesses. The KASAN tests are expecting to explicitly test out-of-bounds conditions at run-time, so hide the variable from GCC, to avoid warnings like:
../lib/test_kasan.c: In function 'ksize_uaf': ../lib/test_kasan.c:790:61: warning: array subscript 120 is outside array bounds of 'void[120]' [-Warray-bounds] 790 | KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]); | ~~~~~~~~~~~~~~~~~~~~~~^~~~~~ ../lib/test_kasan.c:97:9: note: in definition of macro 'KUNIT_EXPECT_KASAN_FAIL' 97 | expression; \ | ^~~~~~~~~~
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: Vincenzo Frascino vincenzo.frascino@arm.com Cc: kasan-dev@googlegroups.com Signed-off-by: Kees Cook keescook@chromium.org Link: https://lore.kernel.org/r/20220608214024.1068451-1-keescook@chromium.org Signed-off-by: Sasha Levin sashal@kernel.org --- lib/test_kasan.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/lib/test_kasan.c b/lib/test_kasan.c index ad880231dfa8..630e0c31d7c2 100644 --- a/lib/test_kasan.c +++ b/lib/test_kasan.c @@ -131,6 +131,7 @@ 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. * Only generic KASAN can precisely detect these. @@ -159,6 +160,7 @@ static void kmalloc_oob_left(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 = *(ptr - 1)); kfree(ptr); } @@ -171,6 +173,7 @@ static void kmalloc_node_oob_right(struct kunit *test) ptr = kmalloc_node(size, GFP_KERNEL, 0); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
+ OPTIMIZER_HIDE_VAR(ptr); KUNIT_EXPECT_KASAN_FAIL(test, ptr[0] = ptr[size]); kfree(ptr); } @@ -191,6 +194,7 @@ 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); @@ -271,6 +275,7 @@ 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); } @@ -410,6 +415,8 @@ static void kmalloc_oob_16(struct kunit *test) ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr2);
+ OPTIMIZER_HIDE_VAR(ptr1); + OPTIMIZER_HIDE_VAR(ptr2); KUNIT_EXPECT_KASAN_FAIL(test, *ptr1 = *ptr2); kfree(ptr1); kfree(ptr2); @@ -756,6 +763,8 @@ static void ksize_unpoisons_memory(struct kunit *test) KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); real_size = ksize(ptr);
+ OPTIMIZER_HIDE_VAR(ptr); + /* This access shouldn't trigger a KASAN report. */ ptr[size] = 'x';
@@ -778,6 +787,7 @@ static void ksize_uaf(struct kunit *test) KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr); kfree(ptr);
+ OPTIMIZER_HIDE_VAR(ptr); KUNIT_EXPECT_KASAN_FAIL(test, ksize(ptr)); KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[0]); KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char *)ptr)[size]);