Commit 263dca23 authored by Feng Jiang's avatar Feng Jiang Committed by Paul Walmsley
Browse files

lib/string_kunit: add correctness test for strnlen() 



Add a KUnit test for strnlen() 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 avatarAndy Shevchenko <andy@kernel.org>
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/20260130025018.172925-3-jiangfeng@kylinos.cn


Signed-off-by: default avatarPaul Walmsley <pjw@kernel.org>
parent ae45f896

lib/tests/string_kunit.c

+35 −0
Original line number Diff line number Diff line
@@ -133,6 +133,40 @@ static void string_test_strlen(struct kunit *test) 
	vfree(buf);

}



static void string_test_strnlen(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';



			if (len > 0)

				KUNIT_EXPECT_EQ(test, strnlen(s, len - 1), len - 1);

			if (len > 1)

				KUNIT_EXPECT_EQ(test, strnlen(s, len - 2), len - 2);



			KUNIT_EXPECT_EQ(test, strnlen(s, len), len);



			KUNIT_EXPECT_EQ(test, strnlen(s, len + 1), len);

			KUNIT_EXPECT_EQ(test, strnlen(s, len + 2), len);

			KUNIT_EXPECT_EQ(test, strnlen(s, len + 10), len);



			s[len] = 'A';

		}

	}



	vfree(buf);

}



static void string_test_strchr(struct kunit *test)

{

	const char *test_string = "abcdefghijkl";
@@ -648,6 +682,7 @@ static struct kunit_case string_test_cases[] = { 
	KUNIT_CASE(string_test_memset32),

	KUNIT_CASE(string_test_memset64),

	KUNIT_CASE(string_test_strlen),

	KUNIT_CASE(string_test_strnlen),

	KUNIT_CASE(string_test_strchr),

	KUNIT_CASE(string_test_strnchr),

	KUNIT_CASE(string_test_strspn),