cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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test_strscpy.c (4112B)

      1// SPDX-License-Identifier: GPL-2.0+
      2
      3#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
      4
      5#include <linux/string.h>
      6
      7#include "../tools/testing/selftests/kselftest_module.h"
      8
      9/*
     10 * Kernel module for testing 'strscpy' family of functions.
     11 */
     12
     13KSTM_MODULE_GLOBALS();
     14
     15/*
     16 * tc() - Run a specific test case.
     17 * @src: Source string, argument to strscpy_pad()
     18 * @count: Size of destination buffer, argument to strscpy_pad()
     19 * @expected: Expected return value from call to strscpy_pad()
     20 * @terminator: 1 if there should be a terminating null byte 0 otherwise.
     21 * @chars: Number of characters from the src string expected to be
     22 *         written to the dst buffer.
     23 * @pad: Number of pad characters expected (in the tail of dst buffer).
     24 *       (@pad does not include the null terminator byte.)
     25 *
     26 * Calls strscpy_pad() and verifies the return value and state of the
     27 * destination buffer after the call returns.
     28 */
     29static int __init tc(char *src, int count, int expected,
     30		     int chars, int terminator, int pad)
     31{
     32	int nr_bytes_poison;
     33	int max_expected;
     34	int max_count;
     35	int written;
     36	char buf[6];
     37	int index, i;
     38	const char POISON = 'z';
     39
     40	total_tests++;
     41
     42	if (!src) {
     43		pr_err("null source string not supported\n");
     44		return -1;
     45	}
     46
     47	memset(buf, POISON, sizeof(buf));
     48	/* Future proofing test suite, validate args */
     49	max_count = sizeof(buf) - 2; /* Space for null and to verify overflow */
     50	max_expected = count - 1;    /* Space for the null */
     51	if (count > max_count) {
     52		pr_err("count (%d) is too big (%d) ... aborting", count, max_count);
     53		return -1;
     54	}
     55	if (expected > max_expected) {
     56		pr_warn("expected (%d) is bigger than can possibly be returned (%d)",
     57			expected, max_expected);
     58	}
     59
     60	written = strscpy_pad(buf, src, count);
     61	if ((written) != (expected)) {
     62		pr_err("%d != %d (written, expected)\n", written, expected);
     63		goto fail;
     64	}
     65
     66	if (count && written == -E2BIG) {
     67		if (strncmp(buf, src, count - 1) != 0) {
     68			pr_err("buffer state invalid for -E2BIG\n");
     69			goto fail;
     70		}
     71		if (buf[count - 1] != '\0') {
     72			pr_err("too big string is not null terminated correctly\n");
     73			goto fail;
     74		}
     75	}
     76
     77	for (i = 0; i < chars; i++) {
     78		if (buf[i] != src[i]) {
     79			pr_err("buf[i]==%c != src[i]==%c\n", buf[i], src[i]);
     80			goto fail;
     81		}
     82	}
     83
     84	if (terminator) {
     85		if (buf[count - 1] != '\0') {
     86			pr_err("string is not null terminated correctly\n");
     87			goto fail;
     88		}
     89	}
     90
     91	for (i = 0; i < pad; i++) {
     92		index = chars + terminator + i;
     93		if (buf[index] != '\0') {
     94			pr_err("padding missing at index: %d\n", i);
     95			goto fail;
     96		}
     97	}
     98
     99	nr_bytes_poison = sizeof(buf) - chars - terminator - pad;
    100	for (i = 0; i < nr_bytes_poison; i++) {
    101		index = sizeof(buf) - 1 - i; /* Check from the end back */
    102		if (buf[index] != POISON) {
    103			pr_err("poison value missing at index: %d\n", i);
    104			goto fail;
    105		}
    106	}
    107
    108	return 0;
    109fail:
    110	failed_tests++;
    111	return -1;
    112}
    113
    114static void __init selftest(void)
    115{
    116	/*
    117	 * tc() uses a destination buffer of size 6 and needs at
    118	 * least 2 characters spare (one for null and one to check for
    119	 * overflow).  This means we should only call tc() with
    120	 * strings up to a maximum of 4 characters long and 'count'
    121	 * should not exceed 4.  To test with longer strings increase
    122	 * the buffer size in tc().
    123	 */
    124
    125	/* tc(src, count, expected, chars, terminator, pad) */
    126	KSTM_CHECK_ZERO(tc("a", 0, -E2BIG, 0, 0, 0));
    127	KSTM_CHECK_ZERO(tc("", 0, -E2BIG, 0, 0, 0));
    128
    129	KSTM_CHECK_ZERO(tc("a", 1, -E2BIG, 0, 1, 0));
    130	KSTM_CHECK_ZERO(tc("", 1, 0, 0, 1, 0));
    131
    132	KSTM_CHECK_ZERO(tc("ab", 2, -E2BIG, 1, 1, 0));
    133	KSTM_CHECK_ZERO(tc("a", 2, 1, 1, 1, 0));
    134	KSTM_CHECK_ZERO(tc("", 2, 0, 0, 1, 1));
    135
    136	KSTM_CHECK_ZERO(tc("abc", 3, -E2BIG, 2, 1, 0));
    137	KSTM_CHECK_ZERO(tc("ab", 3, 2, 2, 1, 0));
    138	KSTM_CHECK_ZERO(tc("a", 3, 1, 1, 1, 1));
    139	KSTM_CHECK_ZERO(tc("", 3, 0, 0, 1, 2));
    140
    141	KSTM_CHECK_ZERO(tc("abcd", 4, -E2BIG, 3, 1, 0));
    142	KSTM_CHECK_ZERO(tc("abc", 4, 3, 3, 1, 0));
    143	KSTM_CHECK_ZERO(tc("ab", 4, 2, 2, 1, 1));
    144	KSTM_CHECK_ZERO(tc("a", 4, 1, 1, 1, 2));
    145	KSTM_CHECK_ZERO(tc("", 4, 0, 0, 1, 3));
    146}
    147
    148KSTM_MODULE_LOADERS(test_strscpy);
    149MODULE_AUTHOR("Tobin C. Harding <tobin@kernel.org>");
    150MODULE_LICENSE("GPL");