linux/lib/string_kunit.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Test cases for string functions.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <kunit/test.h>
#include <linux/module.h>
#include <linux/printk.h>
#include <linux/slab.h>
#include <linux/string.h>
#define STRCMP_LARGE_BUF_LEN 2048
#define STRCMP_CHANGE_POINT 1337
#define STRCMP_TEST_EXPECT_EQUAL(test, fn, ...) KUNIT_EXPECT_EQ(test, fn(__VA_ARGS__), 0)
#define STRCMP_TEST_EXPECT_LOWER(test, fn, ...) KUNIT_EXPECT_LT(test, fn(__VA_ARGS__), 0)
#define STRCMP_TEST_EXPECT_GREATER(test, fn, ...) KUNIT_EXPECT_GT(test, fn(__VA_ARGS__), 0)
static void string_test_memset16(struct kunit *test)
{
unsigned i, j, k;
u16 v, *p;
p = kunit_kzalloc(test, 256 * 2 * 2, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p);
for (i = 0; i < 256; i++) {
for (j = 0; j < 256; j++) {
memset(p, 0xa1, 256 * 2 * sizeof(v));
memset16(p + i, 0xb1b2, j);
for (k = 0; k < 512; k++) {
v = p[k];
if (k < i) {
KUNIT_ASSERT_EQ_MSG(test, v, 0xa1a1,
"i:%d j:%d k:%d", i, j, k);
} else if (k < i + j) {
KUNIT_ASSERT_EQ_MSG(test, v, 0xb1b2,
"i:%d j:%d k:%d", i, j, k);
} else {
KUNIT_ASSERT_EQ_MSG(test, v, 0xa1a1,
"i:%d j:%d k:%d", i, j, k);
}
}
}
}
}
static void string_test_memset32(struct kunit *test)
{
unsigned i, j, k;
u32 v, *p;
p = kunit_kzalloc(test, 256 * 2 * 4, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p);
for (i = 0; i < 256; i++) {
for (j = 0; j < 256; j++) {
memset(p, 0xa1, 256 * 2 * sizeof(v));
memset32(p + i, 0xb1b2b3b4, j);
for (k = 0; k < 512; k++) {
v = p[k];
if (k < i) {
KUNIT_ASSERT_EQ_MSG(test, v, 0xa1a1a1a1,
"i:%d j:%d k:%d", i, j, k);
} else if (k < i + j) {
KUNIT_ASSERT_EQ_MSG(test, v, 0xb1b2b3b4,
"i:%d j:%d k:%d", i, j, k);
} else {
KUNIT_ASSERT_EQ_MSG(test, v, 0xa1a1a1a1,
"i:%d j:%d k:%d", i, j, k);
}
}
}
}
}
static void string_test_memset64(struct kunit *test)
{
unsigned i, j, k;
u64 v, *p;
p = kunit_kzalloc(test, 256 * 2 * 8, GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, p);
for (i = 0; i < 256; i++) {
for (j = 0; j < 256; j++) {
memset(p, 0xa1, 256 * 2 * sizeof(v));
memset64(p + i, 0xb1b2b3b4b5b6b7b8ULL, j);
for (k = 0; k < 512; k++) {
v = p[k];
if (k < i) {
KUNIT_ASSERT_EQ_MSG(test, v, 0xa1a1a1a1a1a1a1a1ULL,
"i:%d j:%d k:%d", i, j, k);
} else if (k < i + j) {
KUNIT_ASSERT_EQ_MSG(test, v, 0xb1b2b3b4b5b6b7b8ULL,
"i:%d j:%d k:%d", i, j, k);
} else {
KUNIT_ASSERT_EQ_MSG(test, v, 0xa1a1a1a1a1a1a1a1ULL,
"i:%d j:%d k:%d", i, j, k);
}
}
}
}
}
static void string_test_strchr(struct kunit *test)
{
const char *test_string = "abcdefghijkl";
const char *empty_string = "";
char *result;
int i;
for (i = 0; i < strlen(test_string) + 1; i++) {
result = strchr(test_string, test_string[i]);
KUNIT_ASSERT_EQ_MSG(test, result - test_string, i,
"char:%c", 'a' + i);
}
result = strchr(empty_string, '\0');
KUNIT_ASSERT_PTR_EQ(test, result, empty_string);
result = strchr(empty_string, 'a');
KUNIT_ASSERT_NULL(test, result);
result = strchr(test_string, 'z');
KUNIT_ASSERT_NULL(test, result);
}
static void string_test_strnchr(struct kunit *test)
{
const char *test_string = "abcdefghijkl";
const char *empty_string = "";
char *result;
int i, j;
for (i = 0; i < strlen(test_string) + 1; i++) {
for (j = 0; j < strlen(test_string) + 2; j++) {
result = strnchr(test_string, j, test_string[i]);
if (j <= i) {
KUNIT_ASSERT_NULL_MSG(test, result,
"char:%c i:%d j:%d", 'a' + i, i, j);
} else {
KUNIT_ASSERT_EQ_MSG(test, result - test_string, i,
"char:%c i:%d j:%d", 'a' + i, i, j);
}
}
}
result = strnchr(empty_string, 0, '\0');
KUNIT_ASSERT_NULL(test, result);
result = strnchr(empty_string, 1, '\0');
KUNIT_ASSERT_PTR_EQ(test, result, empty_string);
result = strnchr(empty_string, 1, 'a');
KUNIT_ASSERT_NULL(test, result);
result = strnchr(NULL, 0, '\0');
KUNIT_ASSERT_NULL(test, result);
}
static void string_test_strspn(struct kunit *test)
{
static const struct strspn_test {
const char str[16];
const char accept[16];
const char reject[16];
unsigned a;
unsigned r;
} tests[] = {
{ "foobar", "", "", 0, 6 },
{ "abba", "abc", "ABBA", 4, 4 },
{ "abba", "a", "b", 1, 1 },
{ "", "abc", "abc", 0, 0},
};
const struct strspn_test *s = tests;
size_t i;
for (i = 0; i < ARRAY_SIZE(tests); ++i, ++s) {
KUNIT_ASSERT_EQ_MSG(test, s->a, strspn(s->str, s->accept),
"i:%zu", i);
KUNIT_ASSERT_EQ_MSG(test, s->r, strcspn(s->str, s->reject),
"i:%zu", i);
}
}
static char strcmp_buffer1[STRCMP_LARGE_BUF_LEN];
static char strcmp_buffer2[STRCMP_LARGE_BUF_LEN];
static void strcmp_fill_buffers(char fill1, char fill2)
{
memset(strcmp_buffer1, fill1, STRCMP_LARGE_BUF_LEN);
memset(strcmp_buffer2, fill2, STRCMP_LARGE_BUF_LEN);
strcmp_buffer1[STRCMP_LARGE_BUF_LEN - 1] = 0;
strcmp_buffer2[STRCMP_LARGE_BUF_LEN - 1] = 0;
}
static void string_test_strcmp(struct kunit *test)
{
/* Equal strings */
STRCMP_TEST_EXPECT_EQUAL(test, strcmp, "Hello, Kernel!", "Hello, Kernel!");
/* First string is lexicographically less than the second */
STRCMP_TEST_EXPECT_LOWER(test, strcmp, "Hello, KUnit!", "Hello, Kernel!");
/* First string is lexicographically larger than the second */
STRCMP_TEST_EXPECT_GREATER(test, strcmp, "Hello, Kernel!", "Hello, KUnit!");
/* Empty string is always lexicographically less than any non-empty string */
STRCMP_TEST_EXPECT_LOWER(test, strcmp, "", "Non-empty string");
/* Two empty strings should be equal */
STRCMP_TEST_EXPECT_EQUAL(test, strcmp, "", "");
/* Compare two strings which have only one char difference */
STRCMP_TEST_EXPECT_LOWER(test, strcmp, "Abacaba", "Abadaba");
/* Compare two strings which have the same prefix*/
STRCMP_TEST_EXPECT_LOWER(test, strcmp, "Just a string", "Just a string and something else");
}
static void string_test_strcmp_long_strings(struct kunit *test)
{
strcmp_fill_buffers('B', 'B');
STRCMP_TEST_EXPECT_EQUAL(test, strcmp, strcmp_buffer1, strcmp_buffer2);
strcmp_buffer1[STRCMP_CHANGE_POINT] = 'A';
STRCMP_TEST_EXPECT_LOWER(test, strcmp, strcmp_buffer1, strcmp_buffer2);
strcmp_buffer1[STRCMP_CHANGE_POINT] = 'C';
STRCMP_TEST_EXPECT_GREATER(test, strcmp, strcmp_buffer1, strcmp_buffer2);
}
static void string_test_strncmp(struct kunit *test)
{
/* Equal strings */
STRCMP_TEST_EXPECT_EQUAL(test, strncmp, "Hello, KUnit!", "Hello, KUnit!", 13);
/* First string is lexicographically less than the second */
STRCMP_TEST_EXPECT_LOWER(test, strncmp, "Hello, KUnit!", "Hello, Kernel!", 13);
/* Result is always 'equal' when count = 0 */
STRCMP_TEST_EXPECT_EQUAL(test, strncmp, "Hello, Kernel!", "Hello, KUnit!", 0);
/* Strings with common prefix are equal if count = length of prefix */
STRCMP_TEST_EXPECT_EQUAL(test, strncmp, "Abacaba", "Abadaba", 3);
/* Strings with common prefix are not equal when count = length of prefix + 1 */
STRCMP_TEST_EXPECT_LOWER(test, strncmp, "Abacaba", "Abadaba", 4);
/* If one string is a prefix of another, the shorter string is lexicographically smaller */
STRCMP_TEST_EXPECT_LOWER(test, strncmp, "Just a string", "Just a string and something else",
strlen("Just a string and something else"));
/*
* If one string is a prefix of another, and we check first length
* of prefix chars, the result is 'equal'
*/
STRCMP_TEST_EXPECT_EQUAL(test, strncmp, "Just a string", "Just a string and something else",
strlen("Just a string"));
}
static void string_test_strncmp_long_strings(struct kunit *test)
{
strcmp_fill_buffers('B', 'B');
STRCMP_TEST_EXPECT_EQUAL(test, strncmp, strcmp_buffer1,
strcmp_buffer2, STRCMP_LARGE_BUF_LEN);
strcmp_buffer1[STRCMP_CHANGE_POINT] = 'A';
STRCMP_TEST_EXPECT_LOWER(test, strncmp, strcmp_buffer1,
strcmp_buffer2, STRCMP_LARGE_BUF_LEN);
strcmp_buffer1[STRCMP_CHANGE_POINT] = 'C';
STRCMP_TEST_EXPECT_GREATER(test, strncmp, strcmp_buffer1,
strcmp_buffer2, STRCMP_LARGE_BUF_LEN);
/* the strings are equal up to STRCMP_CHANGE_POINT */
STRCMP_TEST_EXPECT_EQUAL(test, strncmp, strcmp_buffer1,
strcmp_buffer2, STRCMP_CHANGE_POINT);
STRCMP_TEST_EXPECT_GREATER(test, strncmp, strcmp_buffer1,
strcmp_buffer2, STRCMP_CHANGE_POINT + 1);
}
static void string_test_strcasecmp(struct kunit *test)
{
/* Same strings in different case should be equal */
STRCMP_TEST_EXPECT_EQUAL(test, strcasecmp, "Hello, Kernel!", "HeLLO, KErNeL!");
/* Empty strings should be equal */
STRCMP_TEST_EXPECT_EQUAL(test, strcasecmp, "", "");
/* Despite ascii code for 'a' is larger than ascii code for 'B', 'a' < 'B' */
STRCMP_TEST_EXPECT_LOWER(test, strcasecmp, "a", "B");
STRCMP_TEST_EXPECT_GREATER(test, strcasecmp, "B", "a");
/* Special symbols and numbers should be processed correctly */
STRCMP_TEST_EXPECT_EQUAL(test, strcasecmp, "-+**.1230ghTTT~^", "-+**.1230Ghttt~^");
}
static void string_test_strcasecmp_long_strings(struct kunit *test)
{
strcmp_fill_buffers('b', 'B');
STRCMP_TEST_EXPECT_EQUAL(test, strcasecmp, strcmp_buffer1, strcmp_buffer2);
strcmp_buffer1[STRCMP_CHANGE_POINT] = 'a';
STRCMP_TEST_EXPECT_LOWER(test, strcasecmp, strcmp_buffer1, strcmp_buffer2);
strcmp_buffer1[STRCMP_CHANGE_POINT] = 'C';
STRCMP_TEST_EXPECT_GREATER(test, strcasecmp, strcmp_buffer1, strcmp_buffer2);
}
static void string_test_strncasecmp(struct kunit *test)
{
/* Same strings in different case should be equal */
STRCMP_TEST_EXPECT_EQUAL(test, strncasecmp, "AbAcAbA", "Abacaba", strlen("Abacaba"));
/* strncasecmp should check 'count' chars only */
STRCMP_TEST_EXPECT_EQUAL(test, strncasecmp, "AbaCaBa", "abaCaDa", 5);
STRCMP_TEST_EXPECT_LOWER(test, strncasecmp, "a", "B", 1);
STRCMP_TEST_EXPECT_GREATER(test, strncasecmp, "B", "a", 1);
/* Result is always 'equal' when count = 0 */
STRCMP_TEST_EXPECT_EQUAL(test, strncasecmp, "Abacaba", "Not abacaba", 0);
}
static void string_test_strncasecmp_long_strings(struct kunit *test)
{
strcmp_fill_buffers('b', 'B');
STRCMP_TEST_EXPECT_EQUAL(test, strncasecmp, strcmp_buffer1,
strcmp_buffer2, STRCMP_LARGE_BUF_LEN);
strcmp_buffer1[STRCMP_CHANGE_POINT] = 'a';
STRCMP_TEST_EXPECT_LOWER(test, strncasecmp, strcmp_buffer1,
strcmp_buffer2, STRCMP_LARGE_BUF_LEN);
strcmp_buffer1[STRCMP_CHANGE_POINT] = 'C';
STRCMP_TEST_EXPECT_GREATER(test, strncasecmp, strcmp_buffer1,
strcmp_buffer2, STRCMP_LARGE_BUF_LEN);
STRCMP_TEST_EXPECT_EQUAL(test, strncasecmp, strcmp_buffer1,
strcmp_buffer2, STRCMP_CHANGE_POINT);
STRCMP_TEST_EXPECT_GREATER(test, strncasecmp, strcmp_buffer1,
strcmp_buffer2, STRCMP_CHANGE_POINT + 1);
}
/**
* strscpy_check() - Run a specific test case.
* @test: KUnit test context pointer
* @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()
* @chars: Number of characters from the src string expected to be
* written to the dst buffer.
* @terminator: 1 if there should be a terminating null byte 0 otherwise.
* @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 void strscpy_check(struct kunit *test, 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';
KUNIT_ASSERT_TRUE_MSG(test, src != NULL,
"null source string not supported");
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 */
KUNIT_ASSERT_LE_MSG(test, count, max_count,
"count (%d) is too big (%d) ... aborting", count, max_count);
KUNIT_EXPECT_LE_MSG(test, expected, max_expected,
"expected (%d) is bigger than can possibly be returned (%d)",
expected, max_expected);
written = strscpy_pad(buf, src, count);
KUNIT_ASSERT_EQ(test, written, expected);
if (count && written == -E2BIG) {
KUNIT_ASSERT_EQ_MSG(test, 0, strncmp(buf, src, count - 1),
"buffer state invalid for -E2BIG");
KUNIT_ASSERT_EQ_MSG(test, buf[count - 1], '\0',
"too big string is not null terminated correctly");
}
for (i = 0; i < chars; i++)
KUNIT_ASSERT_EQ_MSG(test, buf[i], src[i],
"buf[i]==%c != src[i]==%c", buf[i], src[i]);
if (terminator)
KUNIT_ASSERT_EQ_MSG(test, buf[count - 1], '\0',
"string is not null terminated correctly");
for (i = 0; i < pad; i++) {
index = chars + terminator + i;
KUNIT_ASSERT_EQ_MSG(test, buf[index], '\0',
"padding missing at index: %d", i);
}
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 */
KUNIT_ASSERT_EQ_MSG(test, buf[index], POISON,
"poison value missing at index: %d", i);
}
}
static void string_test_strscpy(struct kunit *test)
{
char dest[8];
/*
* strscpy_check() 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().
*/
/* strscpy_check(test, src, count, expected, chars, terminator, pad) */
strscpy_check(test, "a", 0, -E2BIG, 0, 0, 0);
strscpy_check(test, "", 0, -E2BIG, 0, 0, 0);
strscpy_check(test, "a", 1, -E2BIG, 0, 1, 0);
strscpy_check(test, "", 1, 0, 0, 1, 0);
strscpy_check(test, "ab", 2, -E2BIG, 1, 1, 0);
strscpy_check(test, "a", 2, 1, 1, 1, 0);
strscpy_check(test, "", 2, 0, 0, 1, 1);
strscpy_check(test, "abc", 3, -E2BIG, 2, 1, 0);
strscpy_check(test, "ab", 3, 2, 2, 1, 0);
strscpy_check(test, "a", 3, 1, 1, 1, 1);
strscpy_check(test, "", 3, 0, 0, 1, 2);
strscpy_check(test, "abcd", 4, -E2BIG, 3, 1, 0);
strscpy_check(test, "abc", 4, 3, 3, 1, 0);
strscpy_check(test, "ab", 4, 2, 2, 1, 1);
strscpy_check(test, "a", 4, 1, 1, 1, 2);
strscpy_check(test, "", 4, 0, 0, 1, 3);
/* Compile-time-known source strings. */
KUNIT_EXPECT_EQ(test, strscpy(dest, "", ARRAY_SIZE(dest)), 0);
KUNIT_EXPECT_EQ(test, strscpy(dest, "", 3), 0);
KUNIT_EXPECT_EQ(test, strscpy(dest, "", 1), 0);
KUNIT_EXPECT_EQ(test, strscpy(dest, "", 0), -E2BIG);
KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", ARRAY_SIZE(dest)), 5);
KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", 3), -E2BIG);
KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", 1), -E2BIG);
KUNIT_EXPECT_EQ(test, strscpy(dest, "Fixed", 0), -E2BIG);
KUNIT_EXPECT_EQ(test, strscpy(dest, "This is too long", ARRAY_SIZE(dest)), -E2BIG);
}
static volatile int unconst;
static void string_test_strcat(struct kunit *test)
{
char dest[8];
/* Destination is terminated. */
memset(dest, 0, sizeof(dest));
KUNIT_EXPECT_EQ(test, strlen(dest), 0);
/* Empty copy does nothing. */
KUNIT_EXPECT_TRUE(test, strcat(dest, "") == dest);
KUNIT_EXPECT_STREQ(test, dest, "");
/* 4 characters copied in, stops at %NUL. */
KUNIT_EXPECT_TRUE(test, strcat(dest, "four\000123") == dest);
KUNIT_EXPECT_STREQ(test, dest, "four");
KUNIT_EXPECT_EQ(test, dest[5], '\0');
/* 2 more characters copied in okay. */
KUNIT_EXPECT_TRUE(test, strcat(dest, "AB") == dest);
KUNIT_EXPECT_STREQ(test, dest, "fourAB");
}
static void string_test_strncat(struct kunit *test)
{
char dest[8];
/* Destination is terminated. */
memset(dest, 0, sizeof(dest));
KUNIT_EXPECT_EQ(test, strlen(dest), 0);
/* Empty copy of size 0 does nothing. */
KUNIT_EXPECT_TRUE(test, strncat(dest, "", 0 + unconst) == dest);
KUNIT_EXPECT_STREQ(test, dest, "");
/* Empty copy of size 1 does nothing too. */
KUNIT_EXPECT_TRUE(test, strncat(dest, "", 1 + unconst) == dest);
KUNIT_EXPECT_STREQ(test, dest, "");
/* Copy of max 0 characters should do nothing. */
KUNIT_EXPECT_TRUE(test, strncat(dest, "asdf", 0 + unconst) == dest);
KUNIT_EXPECT_STREQ(test, dest, "");
/* 4 characters copied in, even if max is 8. */
KUNIT_EXPECT_TRUE(test, strncat(dest, "four\000123", 8 + unconst) == dest);
KUNIT_EXPECT_STREQ(test, dest, "four");
KUNIT_EXPECT_EQ(test, dest[5], '\0');
KUNIT_EXPECT_EQ(test, dest[6], '\0');
/* 2 characters copied in okay, 2 ignored. */
KUNIT_EXPECT_TRUE(test, strncat(dest, "ABCD", 2 + unconst) == dest);
KUNIT_EXPECT_STREQ(test, dest, "fourAB");
}
static void string_test_strlcat(struct kunit *test)
{
char dest[8] = "";
int len = sizeof(dest) + unconst;
/* Destination is terminated. */
KUNIT_EXPECT_EQ(test, strlen(dest), 0);
/* Empty copy is size 0. */
KUNIT_EXPECT_EQ(test, strlcat(dest, "", len), 0);
KUNIT_EXPECT_STREQ(test, dest, "");
/* Size 1 should keep buffer terminated, report size of source only. */
KUNIT_EXPECT_EQ(test, strlcat(dest, "four", 1 + unconst), 4);
KUNIT_EXPECT_STREQ(test, dest, "");
/* 4 characters copied in. */
KUNIT_EXPECT_EQ(test, strlcat(dest, "four", len), 4);
KUNIT_EXPECT_STREQ(test, dest, "four");
/* 2 characters copied in okay, gets to 6 total. */
KUNIT_EXPECT_EQ(test, strlcat(dest, "AB", len), 6);
KUNIT_EXPECT_STREQ(test, dest, "fourAB");
/* 2 characters ignored if max size (7) reached. */
KUNIT_EXPECT_EQ(test, strlcat(dest, "CD", 7 + unconst), 8);
KUNIT_EXPECT_STREQ(test, dest, "fourAB");
/* 1 of 2 characters skipped, now at true max size. */
KUNIT_EXPECT_EQ(test, strlcat(dest, "EFG", len), 9);
KUNIT_EXPECT_STREQ(test, dest, "fourABE");
/* Everything else ignored, now at full size. */
KUNIT_EXPECT_EQ(test, strlcat(dest, "1234", len), 11);
KUNIT_EXPECT_STREQ(test, dest, "fourABE");
}
static void string_test_strtomem(struct kunit *test)
{
static const char input[sizeof(unsigned long)] = "hi";
static const char truncate[] = "this is too long";
struct {
unsigned long canary1;
unsigned char output[sizeof(unsigned long)] __nonstring;
unsigned long canary2;
} wrap;
memset(&wrap, 0xFF, sizeof(wrap));
KUNIT_EXPECT_EQ_MSG(test, wrap.canary1, ULONG_MAX,
"bad initial canary value");
KUNIT_EXPECT_EQ_MSG(test, wrap.canary2, ULONG_MAX,
"bad initial canary value");
/* Check unpadded copy leaves surroundings untouched. */
strtomem(wrap.output, input);
KUNIT_EXPECT_EQ(test, wrap.canary1, ULONG_MAX);
KUNIT_EXPECT_EQ(test, wrap.output[0], input[0]);
KUNIT_EXPECT_EQ(test, wrap.output[1], input[1]);
for (size_t i = 2; i < sizeof(wrap.output); i++)
KUNIT_EXPECT_EQ(test, wrap.output[i], 0xFF);
KUNIT_EXPECT_EQ(test, wrap.canary2, ULONG_MAX);
/* Check truncated copy leaves surroundings untouched. */
memset(&wrap, 0xFF, sizeof(wrap));
strtomem(wrap.output, truncate);
KUNIT_EXPECT_EQ(test, wrap.canary1, ULONG_MAX);
for (size_t i = 0; i < sizeof(wrap.output); i++)
KUNIT_EXPECT_EQ(test, wrap.output[i], truncate[i]);
KUNIT_EXPECT_EQ(test, wrap.canary2, ULONG_MAX);
/* Check padded copy leaves only string padded. */
memset(&wrap, 0xFF, sizeof(wrap));
strtomem_pad(wrap.output, input, 0xAA);
KUNIT_EXPECT_EQ(test, wrap.canary1, ULONG_MAX);
KUNIT_EXPECT_EQ(test, wrap.output[0], input[0]);
KUNIT_EXPECT_EQ(test, wrap.output[1], input[1]);
for (size_t i = 2; i < sizeof(wrap.output); i++)
KUNIT_EXPECT_EQ(test, wrap.output[i], 0xAA);
KUNIT_EXPECT_EQ(test, wrap.canary2, ULONG_MAX);
/* Check truncated padded copy has no padding. */
memset(&wrap, 0xFF, sizeof(wrap));
strtomem(wrap.output, truncate);
KUNIT_EXPECT_EQ(test, wrap.canary1, ULONG_MAX);
for (size_t i = 0; i < sizeof(wrap.output); i++)
KUNIT_EXPECT_EQ(test, wrap.output[i], truncate[i]);
KUNIT_EXPECT_EQ(test, wrap.canary2, ULONG_MAX);
}
string.h: Introduce memtostr() and memtostr_pad() 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>
2024-04-10 10:31:50 +08:00
static void string_test_memtostr(struct kunit *test)
{
char nonstring[7] = { 'a', 'b', 'c', 'd', 'e', 'f', 'g' };
char nonstring_small[3] = { 'a', 'b', 'c' };
char dest[sizeof(nonstring) + 1];
/* Copy in a non-NUL-terminated string into exactly right-sized dest. */
KUNIT_EXPECT_EQ(test, sizeof(dest), sizeof(nonstring) + 1);
memset(dest, 'X', sizeof(dest));
memtostr(dest, nonstring);
KUNIT_EXPECT_STREQ(test, dest, "abcdefg");
memset(dest, 'X', sizeof(dest));
memtostr(dest, nonstring_small);
KUNIT_EXPECT_STREQ(test, dest, "abc");
KUNIT_EXPECT_EQ(test, dest[7], 'X');
memset(dest, 'X', sizeof(dest));
memtostr_pad(dest, nonstring);
KUNIT_EXPECT_STREQ(test, dest, "abcdefg");
memset(dest, 'X', sizeof(dest));
memtostr_pad(dest, nonstring_small);
KUNIT_EXPECT_STREQ(test, dest, "abc");
KUNIT_EXPECT_EQ(test, dest[7], '\0');
}
static struct kunit_case string_test_cases[] = {
KUNIT_CASE(string_test_memset16),
KUNIT_CASE(string_test_memset32),
KUNIT_CASE(string_test_memset64),
KUNIT_CASE(string_test_strchr),
KUNIT_CASE(string_test_strnchr),
KUNIT_CASE(string_test_strspn),
KUNIT_CASE(string_test_strcmp),
KUNIT_CASE(string_test_strcmp_long_strings),
KUNIT_CASE(string_test_strncmp),
KUNIT_CASE(string_test_strncmp_long_strings),
KUNIT_CASE(string_test_strcasecmp),
KUNIT_CASE(string_test_strcasecmp_long_strings),
KUNIT_CASE(string_test_strncasecmp),
KUNIT_CASE(string_test_strncasecmp_long_strings),
KUNIT_CASE(string_test_strscpy),
KUNIT_CASE(string_test_strcat),
KUNIT_CASE(string_test_strncat),
KUNIT_CASE(string_test_strlcat),
KUNIT_CASE(string_test_strtomem),
string.h: Introduce memtostr() and memtostr_pad() 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>
2024-04-10 10:31:50 +08:00
KUNIT_CASE(string_test_memtostr),
{}
};
static struct kunit_suite string_test_suite = {
.name = "string",
.test_cases = string_test_cases,
};
kunit_test_suites(&string_test_suite);
MODULE_DESCRIPTION("Test cases for string functions");
MODULE_LICENSE("GPL v2");