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