From 9dd5134c61580ba4c219296c37e08ff64c109a74 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Mon, 10 Jun 2024 11:23:05 -0700 Subject: [PATCH] kunit/overflow: Adjust for __counted_by with DEFINE_RAW_FLEX() When a flexible array structure has a __counted_by annotation, its use with DEFINE_RAW_FLEX() will result in the count being zero-initialized. This is expected since one doesn't want to use RAW with a counted_by struct. Adjust the tests to check for the condition and for compiler support. Reported-by: Christian Schrefl Closes: https://lore.kernel.org/all/0bfc6b38-8bc5-4971-b6fb-dc642a73fbfe@gmail.com/ Suggested-by: Nathan Chancellor Reviewed-by: Nathan Chancellor Link: https://lore.kernel.org/r/20240610182301.work.272-kees@kernel.org Tested-by: Christian Schrefl Reviewed-by: Christian Schrefl Signed-off-by: Kees Cook --- lib/overflow_kunit.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/lib/overflow_kunit.c b/lib/overflow_kunit.c index 4ef31b0bb74d6..d305b0c054bb7 100644 --- a/lib/overflow_kunit.c +++ b/lib/overflow_kunit.c @@ -1178,14 +1178,28 @@ struct foo { s16 array[] __counted_by(counter); }; +struct bar { + int a; + u32 counter; + s16 array[]; +}; + static void DEFINE_FLEX_test(struct kunit *test) { - DEFINE_RAW_FLEX(struct foo, two, array, 2); + /* Using _RAW_ on a __counted_by struct will initialize "counter" to zero */ + DEFINE_RAW_FLEX(struct foo, two_but_zero, array, 2); +#if __has_attribute(__counted_by__) + int expected_raw_size = sizeof(struct foo); +#else + int expected_raw_size = sizeof(struct foo) + 2 * sizeof(s16); +#endif + /* Without annotation, it will always be on-stack size. */ + DEFINE_RAW_FLEX(struct bar, two, array, 2); DEFINE_FLEX(struct foo, eight, array, counter, 8); DEFINE_FLEX(struct foo, empty, array, counter, 0); - KUNIT_EXPECT_EQ(test, __struct_size(two), - sizeof(struct foo) + sizeof(s16) + sizeof(s16)); + KUNIT_EXPECT_EQ(test, __struct_size(two_but_zero), expected_raw_size); + KUNIT_EXPECT_EQ(test, __struct_size(two), sizeof(struct bar) + 2 * sizeof(s16)); KUNIT_EXPECT_EQ(test, __struct_size(eight), 24); KUNIT_EXPECT_EQ(test, __struct_size(empty), sizeof(struct foo)); } -- 2.50.1