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: Kees Cook <[email protected]> Signed-off-by: Feng Jiang <[email protected]> --- lib/tests/string_kunit.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) diff --git a/lib/tests/string_kunit.c b/lib/tests/string_kunit.c index 886d21d32fa9..f16dfa29e8ce 100644 --- a/lib/tests/string_kunit.c +++ b/lib/tests/string_kunit.c @@ -189,6 +189,36 @@ 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"; @@ -684,6 +714,7 @@ 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), -- 2.25.1
