It is more logical to have the strtomem() test in string_kunit.c instead
of the memcpy() suite. Move it to live with memtostr().
Signed-off-by: Kees Cook <keescook@chromium.org>
Another ambiguous use of strncpy() is to copy from strings that may not
be NUL-terminated. These cases depend on having the destination buffer
be explicitly larger than the source buffer's maximum size, having
the size of the copy exactly match the source buffer's maximum size,
and for the destination buffer to get explicitly NUL terminated.
This usually happens when parsing protocols or hardware character arrays
that are not guaranteed to be NUL-terminated. The code pattern is
effectively this:
char dest[sizeof(src) + 1];
strncpy(dest, src, sizeof(src));
dest[sizeof(dest) - 1] = '\0';
In practice it usually looks like:
struct from_hardware {
...
char name[HW_NAME_SIZE] __nonstring;
...
};
struct from_hardware *p = ...;
char name[HW_NAME_SIZE + 1];
strncpy(name, p->name, HW_NAME_SIZE);
name[NW_NAME_SIZE] = '\0';
This cannot be replaced with:
strscpy(name, p->name, sizeof(name));
because p->name is smaller and not NUL-terminated, so FORTIFY will
trigger when strnlen(p->name, sizeof(name)) is used. And it cannot be
replaced with:
strscpy(name, p->name, sizeof(p->name));
because then "name" may contain a 1 character early truncation of
p->name.
Provide an unambiguous interface for converting a maybe not-NUL-terminated
string to a NUL-terminated string, with compile-time buffer size checking
so that it can never fail at runtime: memtostr() and memtostr_pad(). Also
add KUnit tests for both.
Link: https://lore.kernel.org/r/20240410023155.2100422-1-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
The KUnit convention for test names is AREA_test_WHAT. Adjust the string
test names to follow this pattern.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Tested-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Link: https://lore.kernel.org/r/20240419140155.3028912-5-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Move the strcat() tests into string_kunit.c. Remove the separate
Kconfig and Makefile rule.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Tested-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Link: https://lore.kernel.org/r/20240419140155.3028912-4-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Move the strscpy() tests into string_kunit.c. Remove the separate
Kconfig and Makefile rule.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Tested-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Link: https://lore.kernel.org/r/20240419140155.3028912-2-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Currently, str*cmp functions (strcmp, strncmp, strcasecmp and
strncasecmp) are not covered with tests. Extend the `string_kunit.c`
test by adding the test cases for them.
This patch adds 8 more test cases:
1) strcmp test
2) strcmp test on long strings (2048 chars)
3) strncmp test
4) strncmp test on long strings (2048 chars)
5) strcasecmp test
6) strcasecmp test on long strings
7) strncasecmp test
8) strncasecmp test on long strings
These test cases aim at covering as many edge cases as possible,
including the tests on empty strings, situations when the different
symbol is placed at the end of one of the strings, etc.
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Link: https://lore.kernel.org/r/20240417233033.717596-1-ivan.orlov0322@gmail.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Convert test_string.c to KUnit so it can be easily run with everything
else.
Additional text context is retained for failure reporting. For example,
when forcing a bad match, we can see the loop counters reported for the
memset() tests:
[09:21:52] # test_memset64: ASSERTION FAILED at lib/string_kunit.c:93
[09:21:52] Expected v == 0xa2a1a1a1a1a1a1a1ULL, but
[09:21:52] v == -6799976246779207263 (0xa1a1a1a1a1a1a1a1)
[09:21:52] 0xa2a1a1a1a1a1a1a1ULL == -6727918652741279327 (0xa2a1a1a1a1a1a1a1)
[09:21:52] i:0 j:0 k:0
[09:21:52] [FAILED] test_memset64
Currently passes without problems:
$ ./tools/testing/kunit/kunit.py run string
...
[09:37:40] Starting KUnit Kernel (1/1)...
[09:37:40] ============================================================
[09:37:40] =================== string (6 subtests) ====================
[09:37:40] [PASSED] test_memset16
[09:37:40] [PASSED] test_memset32
[09:37:40] [PASSED] test_memset64
[09:37:40] [PASSED] test_strchr
[09:37:40] [PASSED] test_strnchr
[09:37:40] [PASSED] test_strspn
[09:37:40] ===================== [PASSED] string ======================
[09:37:40] ============================================================
[09:37:40] Testing complete. Ran 6 tests: passed: 6
[09:37:40] Elapsed time: 6.730s total, 0.001s configuring, 6.562s building, 0.131s running
Link: https://lore.kernel.org/r/20240301202732.2688342-1-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Kees Cook