Commit ae45f896 authored by Feng Jiang's avatar Feng Jiang Committed by Paul Walmsley
Browse files

lib/string_kunit: add correctness test for strlen() 



Add a KUnit test for strlen() 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/20260130025018.172925-2-jiangfeng@kylinos.cn


Signed-off-by: default avatarPaul Walmsley <pjw@kernel.org>
parent d7df0505

lib/tests/string_kunit.c

+30 −0
Original line number Diff line number Diff line
@@ -6,10 +6,12 @@ 
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



#include <kunit/test.h>

#include <linux/mm.h>

#include <linux/module.h>

#include <linux/printk.h>

#include <linux/slab.h>

#include <linux/string.h>

#include <linux/vmalloc.h>



#define STRCMP_LARGE_BUF_LEN 2048

#define STRCMP_CHANGE_POINT 1337
@@ -17,6 +19,9 @@ 
#define STRCMP_TEST_EXPECT_LOWER(test, fn, ...) KUNIT_EXPECT_LT(test, fn(__VA_ARGS__), 0)

#define STRCMP_TEST_EXPECT_GREATER(test, fn, ...) KUNIT_EXPECT_GT(test, fn(__VA_ARGS__), 0)



#define STRING_TEST_MAX_LEN	128

#define STRING_TEST_MAX_OFFSET	16



static void string_test_memset16(struct kunit *test)

{

	unsigned i, j, k;
@@ -104,6 +109,30 @@ static void string_test_memset64(struct kunit *test) 
	}

}



static void string_test_strlen(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_EQ_MSG(test, strlen(s), len,

				"offset:%zu len:%zu", offset, len);

			s[len] = 'A';

		}

	}



	vfree(buf);

}



static void string_test_strchr(struct kunit *test)

{

	const char *test_string = "abcdefghijkl";
@@ -618,6 +647,7 @@ static struct kunit_case string_test_cases[] = { 
	KUNIT_CASE(string_test_memset16),

	KUNIT_CASE(string_test_memset32),

	KUNIT_CASE(string_test_memset64),

	KUNIT_CASE(string_test_strlen),

	KUNIT_CASE(string_test_strchr),

	KUNIT_CASE(string_test_strnchr),

	KUNIT_CASE(string_test_strspn),