// SPDX-License-Identifier: GPL-2.0+ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/string.h> #include "../tools/testing/selftests/kselftest_module.h" /* * Kernel module for testing 'strscpy' family of functions. */ KSTM_MODULE_GLOBALS(); /* * tc() - Run a specific test case. * @src: Source string, argument to strscpy_pad() * @count: Size of destination buffer, argument to strscpy_pad() * @expected: Expected return value from call to strscpy_pad() * @terminator: 1 if there should be a terminating null byte 0 otherwise. * @chars: Number of characters from the src string expected to be * written to the dst buffer. * @pad: Number of pad characters expected (in the tail of dst buffer). * (@pad does not include the null terminator byte.) * * Calls strscpy_pad() and verifies the return value and state of the * destination buffer after the call returns. */ static int __init tc(char *src, int count, int expected, int chars, int terminator, int pad) { int nr_bytes_poison; int max_expected; int max_count; int written; char buf[6]; int index, i; const char POISON = 'z'; total_tests++; if (!src) { pr_err("null source string not supported\n"); return -1; } memset(buf, POISON, sizeof(buf)); /* Future proofing test suite, validate args */ max_count = sizeof(buf) - 2; /* Space for null and to verify overflow */ max_expected = count - 1; /* Space for the null */ if (count > max_count) { pr_err("count (%d) is too big (%d) ... aborting", count, max_count); return -1; } if (expected > max_expected) { pr_warn("expected (%d) is bigger than can possibly be returned (%d)", expected, max_expected); } written = strscpy_pad(buf, src, count); if ((written) != (expected)) { pr_err("%d != %d (written, expected)\n", written, expected); goto fail; } if (count && written == -E2BIG) { if (strncmp(buf, src, count - 1) != 0) { pr_err("buffer state invalid for -E2BIG\n"); goto fail; } if (buf[count - 1] != '\0') { pr_err("too big string is not null terminated correctly\n"); goto fail; } } for (i = 0; i < chars; i++) { if (buf[i] != src[i]) { pr_err("buf[i]==%c != src[i]==%c\n", buf[i], src[i]); goto fail; } } if (terminator) { if (buf[count - 1] != '\0') { pr_err("string is not null terminated correctly\n"); goto fail; } } for (i = 0; i < pad; i++) { index = chars + terminator + i; if (buf[index] != '\0') { pr_err("padding missing at index: %d\n", i); goto fail; } } nr_bytes_poison = sizeof(buf) - chars - terminator - pad; for (i = 0; i < nr_bytes_poison; i++) { index = sizeof(buf) - 1 - i; /* Check from the end back */ if (buf[index] != POISON) { pr_err("poison value missing at index: %d\n", i); goto fail; } } return 0; fail: failed_tests++; return -1; } static void __init selftest(void) { /* * tc() uses a destination buffer of size 6 and needs at * least 2 characters spare (one for null and one to check for * overflow). This means we should only call tc() with * strings up to a maximum of 4 characters long and 'count' * should not exceed 4. To test with longer strings increase * the buffer size in tc(). */ /* tc(src, count, expected, chars, terminator, pad) */ KSTM_CHECK_ZERO(tc("a", 0, -E2BIG, 0, 0, 0)); KSTM_CHECK_ZERO(tc("", 0, -E2BIG, 0, 0, 0)); KSTM_CHECK_ZERO(tc("a", 1, -E2BIG, 0, 1, 0)); KSTM_CHECK_ZERO(tc("", 1, 0, 0, 1, 0)); KSTM_CHECK_ZERO(tc("ab", 2, -E2BIG, 1, 1, 0)); KSTM_CHECK_ZERO(tc("a", 2, 1, 1, 1, 0)); KSTM_CHECK_ZERO(tc("", 2, 0, 0, 1, 1)); KSTM_CHECK_ZERO(tc("abc", 3, -E2BIG, 2, 1, 0)); KSTM_CHECK_ZERO(tc("ab", 3, 2, 2, 1, 0)); KSTM_CHECK_ZERO(tc("a", 3, 1, 1, 1, 1)); KSTM_CHECK_ZERO(tc("", 3, 0, 0, 1, 2)); KSTM_CHECK_ZERO(tc("abcd", 4, -E2BIG, 3, 1, 0)); KSTM_CHECK_ZERO(tc("abc", 4, 3, 3, 1, 0)); KSTM_CHECK_ZERO(tc("ab", 4, 2, 2, 1, 1)); KSTM_CHECK_ZERO(tc("a", 4, 1, 1, 1, 2)); KSTM_CHECK_ZERO(tc("", 4, 0, 0, 1, 3)); } KSTM_MODULE_LOADERS(test_strscpy); MODULE_AUTHOR("Tobin C. Harding <tobin@kernel.org>"); MODULE_LICENSE("GPL");