From 74df22453c51392476117d7330bf02cee6e987cf Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 1 May 2024 16:29:48 -0700 Subject: kunit/fortify: Fix replaced failure path to unbreak __alloc_size The __alloc_size annotation for kmemdup() was getting disabled under KUnit testing because the replaced fortify_panic macro implementation was using "return NULL" as a way to survive the sanity checking. But having the chance to return NULL invalidated __alloc_size, so kmemdup was not passing the __builtin_dynamic_object_size() tests any more: [23:26:18] [PASSED] fortify_test_alloc_size_kmalloc_const [23:26:19] # fortify_test_alloc_size_kmalloc_dynamic: EXPECTATION FAILED at lib/fortify_kunit.c:265 [23:26:19] Expected __builtin_dynamic_object_size(p, 1) == expected, but [23:26:19] __builtin_dynamic_object_size(p, 1) == -1 (0xffffffffffffffff) [23:26:19] expected == 11 (0xb) [23:26:19] __alloc_size() not working with __bdos on kmemdup("hello there", len, gfp) [23:26:19] [FAILED] fortify_test_alloc_size_kmalloc_dynamic Normal builds were not affected: __alloc_size continued to work there. Use a zero-sized allocation instead, which allows __alloc_size to behave. Fixes: 4ce615e798a7 ("fortify: Provide KUnit counters for failure testing") Fixes: fa4a3f86d498 ("fortify: Add KUnit tests for runtime overflows") Link: https://lore.kernel.org/r/20240501232937.work.532-kees@kernel.org Signed-off-by: Kees Cook --- lib/fortify_kunit.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'lib/fortify_kunit.c') diff --git a/lib/fortify_kunit.c b/lib/fortify_kunit.c index ef3e4c68b759..306522fd0aa2 100644 --- a/lib/fortify_kunit.c +++ b/lib/fortify_kunit.c @@ -1002,19 +1002,19 @@ static void fortify_test_kmemdup(struct kunit *test) /* Out of bounds by 1 byte. */ copy = kmemdup(src, len + 1, GFP_KERNEL); - KUNIT_EXPECT_NULL(test, copy); + KUNIT_EXPECT_PTR_EQ(test, copy, ZERO_SIZE_PTR); KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1); kfree(copy); /* Way out of bounds. */ copy = kmemdup(src, len * 2, GFP_KERNEL); - KUNIT_EXPECT_NULL(test, copy); + KUNIT_EXPECT_PTR_EQ(test, copy, ZERO_SIZE_PTR); KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2); kfree(copy); /* Starting offset causing out of bounds. */ copy = kmemdup(src + 1, len, GFP_KERNEL); - KUNIT_EXPECT_NULL(test, copy); + KUNIT_EXPECT_PTR_EQ(test, copy, ZERO_SIZE_PTR); KUNIT_EXPECT_EQ(test, fortify_read_overflows, 3); kfree(copy); } -- cgit v1.2.3