Commit 27b2810a authored by Feng Jiang's avatar Feng Jiang Committed by Paul Walmsley
Browse files

lib/string_kunit: add correctness test for strrchr() 



Add a KUnit test for strrchr() to verify correctness across
different string lengths and memory alignments. Use vmalloc()
to place the NUL character at the page boundary to ensure
over-reads are detected.

Suggested-by: default avatarKees Cook <kees@kernel.org>
Signed-off-by: default avatarFeng Jiang <jiangfeng@kylinos.cn>
Reviewed-by: default avatarKees Cook <kees@kernel.org>
Link: https://patch.msgid.link/20260130025018.172925-4-jiangfeng@kylinos.cn


Signed-off-by: default avatarPaul Walmsley <pjw@kernel.org>
parent 263dca23

lib/tests/string_kunit.c

+31 −0
Original line number Diff line number Diff line
@@ -190,6 +190,36 @@ static void string_test_strchr(struct kunit *test) 
	KUNIT_ASSERT_NULL(test, result);

}



static void string_test_strrchr(struct kunit *test)

{

	size_t buf_size;

	char *buf, *s;



	buf_size = PAGE_ALIGN(STRING_TEST_MAX_LEN + STRING_TEST_MAX_OFFSET + 1);

	buf = vmalloc(buf_size);

	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buf);



	memset(buf, 'A', buf_size);



	for (size_t offset = 0; offset < STRING_TEST_MAX_OFFSET; offset++) {

		for (size_t len = 0; len <= STRING_TEST_MAX_LEN; len++) {

			s = buf + buf_size - 1 - offset - len;

			s[len] = '\0';



			KUNIT_EXPECT_PTR_EQ(test, strrchr(s, 'Z'), NULL);



			if (len > 0)

				KUNIT_EXPECT_PTR_EQ(test, strrchr(s, 'A'), s + len - 1);

			else

				KUNIT_EXPECT_PTR_EQ(test, strrchr(s, 'A'), NULL);



			s[len] = 'A';

		}

	}



	vfree(buf);

}



static void string_test_strnchr(struct kunit *test)

{

	const char *test_string = "abcdefghijkl";
@@ -685,6 +715,7 @@ static struct kunit_case string_test_cases[] = { 
	KUNIT_CASE(string_test_strnlen),

	KUNIT_CASE(string_test_strchr),

	KUNIT_CASE(string_test_strnchr),

	KUNIT_CASE(string_test_strrchr),

	KUNIT_CASE(string_test_strspn),

	KUNIT_CASE(string_test_strcmp),

	KUNIT_CASE(string_test_strcmp_long_strings),