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2024-04-24string_kunit: Move strtomem KUnit test to string_kunit.cKees Cook
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>
2024-04-24string.h: Introduce memtostr() and memtostr_pad()Kees Cook
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>
2024-04-19string: Convert KUnit test names to standard conventionKees Cook
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>
2024-04-19string: Merge strcat KUnit tests into string_kunit.cKees Cook
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>
2024-04-19string: Merge strscpy KUnit tests into string_kunit.cKees Cook
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>
2024-04-18string_kunit: Add test cases for str*cmp functionsIvan Orlov
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>
2024-03-05string: Convert selftest to KUnitKees Cook
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>