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| author | Kees Cook <keescook@chromium.org> | 2024-05-01 16:29:48 -0700 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2024-05-01 16:35:06 -0700 |
| commit | 74df22453c51392476117d7330bf02cee6e987cf (patch) | |
| tree | 1fed486e0d7f8044c5a2d86b57599485981a726f | |
| parent | a284e43852380ab71eeb996389e01992d74a8dde (diff) | |
| download | linux-74df22453c51392476117d7330bf02cee6e987cf.tar.gz linux-74df22453c51392476117d7330bf02cee6e987cf.tar.bz2 linux-74df22453c51392476117d7330bf02cee6e987cf.zip | |
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 <keescook@chromium.org>
| -rw-r--r-- | include/linux/fortify-string.h | 3 | ||||
| -rw-r--r-- | lib/fortify_kunit.c | 6 |
2 files changed, 5 insertions, 4 deletions
diff --git a/include/linux/fortify-string.h b/include/linux/fortify-string.h index a0bb13825109..85fc0e6f0f7f 100644 --- a/include/linux/fortify-string.h +++ b/include/linux/fortify-string.h @@ -738,7 +738,8 @@ __FORTIFY_INLINE void *kmemdup(const void * const POS0 p, size_t size, gfp_t gfp if (__compiletime_lessthan(p_size, size)) __read_overflow(); if (p_size < size) - fortify_panic(FORTIFY_FUNC_kmemdup, FORTIFY_READ, p_size, size, NULL); + fortify_panic(FORTIFY_FUNC_kmemdup, FORTIFY_READ, p_size, size, + __real_kmemdup(p, 0, gfp)); return __real_kmemdup(p, size, gfp); } 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); } |