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linux-stable/lib/memcpy_kunit.c
Kees Cook 4acf1de35f kunit: memcpy: Split slow memcpy tests into MEMCPY_SLOW_KUNIT_TEST 
Since the long memcpy tests may stall a system for tens of seconds
in virtualized architecture environments, split those tests off under
CONFIG_MEMCPY_SLOW_KUNIT_TEST so they can be separately disabled.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/lkml/20221226195206.GA2626419@roeck-us.net
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-and-tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: David Gow <davidgow@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
2023-01-25 12:24:40 -08:00

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// SPDX-License-Identifier: GPL-2.0
/*
* Test cases for memcpy(), memmove(), and memset().
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <kunit/test.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/overflow.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
struct some_bytes {
union {
u8 data[32];
struct {
u32 one;
u16 two;
u8 three;
/* 1 byte hole */
u32 four[4];
};
};
};
#define check(instance, v) do { \
BUILD_BUG_ON(sizeof(instance.data) != 32); \
for (size_t i = 0; i < sizeof(instance.data); i++) { \
KUNIT_ASSERT_EQ_MSG(test, instance.data[i], v, \
"line %d: '%s' not initialized to 0x%02x @ %d (saw 0x%02x)\n", \
__LINE__, #instance, v, i, instance.data[i]); \
} \
} while (0)
#define compare(name, one, two) do { \
BUILD_BUG_ON(sizeof(one) != sizeof(two)); \
for (size_t i = 0; i < sizeof(one); i++) { \
KUNIT_EXPECT_EQ_MSG(test, one.data[i], two.data[i], \
"line %d: %s.data[%d] (0x%02x) != %s.data[%d] (0x%02x)\n", \
__LINE__, #one, i, one.data[i], #two, i, two.data[i]); \
} \
kunit_info(test, "ok: " TEST_OP "() " name "\n"); \
} while (0)
static void memcpy_test(struct kunit *test)
{
#define TEST_OP "memcpy"
struct some_bytes control = {
.data = { 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
},
};
struct some_bytes zero = { };
struct some_bytes middle = {
.data = { 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
},
};
struct some_bytes three = {
.data = { 0x00, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x00, 0x00, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
},
};
struct some_bytes dest = { };
int count;
u8 *ptr;
/* Verify static initializers. */
check(control, 0x20);
check(zero, 0);
compare("static initializers", dest, zero);
/* Verify assignment. */
dest = control;
compare("direct assignment", dest, control);
/* Verify complete overwrite. */
memcpy(dest.data, zero.data, sizeof(dest.data));
compare("complete overwrite", dest, zero);
/* Verify middle overwrite. */
dest = control;
memcpy(dest.data + 12, zero.data, 7);
compare("middle overwrite", dest, middle);
/* Verify argument side-effects aren't repeated. */
dest = control;
ptr = dest.data;
count = 1;
memcpy(ptr++, zero.data, count++);
ptr += 8;
memcpy(ptr++, zero.data, count++);
compare("argument side-effects", dest, three);
#undef TEST_OP
}
static unsigned char larger_array [2048];
static void memmove_test(struct kunit *test)
{
#define TEST_OP "memmove"
struct some_bytes control = {
.data = { 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99,
0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99,
0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99,
0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99,
},
};
struct some_bytes zero = { };
struct some_bytes middle = {
.data = { 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99,
0x99, 0x99, 0x99, 0x99, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x99, 0x99, 0x99, 0x99, 0x99,
0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99,
},
};
struct some_bytes five = {
.data = { 0x00, 0x00, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99,
0x99, 0x99, 0x00, 0x00, 0x00, 0x99, 0x99, 0x99,
0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99,
0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99,
},
};
struct some_bytes overlap = {
.data = { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99,
0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99,
},
};
struct some_bytes overlap_expected = {
.data = { 0x00, 0x01, 0x00, 0x01, 0x02, 0x03, 0x04, 0x07,
0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99,
0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99,
},
};
struct some_bytes dest = { };
int count;
u8 *ptr;
/* Verify static initializers. */
check(control, 0x99);
check(zero, 0);
compare("static initializers", zero, dest);
/* Verify assignment. */
dest = control;
compare("direct assignment", dest, control);
/* Verify complete overwrite. */
memmove(dest.data, zero.data, sizeof(dest.data));
compare("complete overwrite", dest, zero);
/* Verify middle overwrite. */
dest = control;
memmove(dest.data + 12, zero.data, 7);
compare("middle overwrite", dest, middle);
/* Verify argument side-effects aren't repeated. */
dest = control;
ptr = dest.data;
count = 2;
memmove(ptr++, zero.data, count++);
ptr += 9;
memmove(ptr++, zero.data, count++);
compare("argument side-effects", dest, five);
/* Verify overlapping overwrite is correct. */
ptr = &overlap.data[2];
memmove(ptr, overlap.data, 5);
compare("overlapping write", overlap, overlap_expected);
/* Verify larger overlapping moves. */
larger_array[256] = 0xAAu;
/*
* Test a backwards overlapping memmove first. 256 and 1024 are
* important for i386 to use rep movsl.
*/
memmove(larger_array, larger_array + 256, 1024);
KUNIT_ASSERT_EQ(test, larger_array[0], 0xAAu);
KUNIT_ASSERT_EQ(test, larger_array[256], 0x00);
KUNIT_ASSERT_NULL(test,
memchr(larger_array + 1, 0xaa, ARRAY_SIZE(larger_array) - 1));
/* Test a forwards overlapping memmove. */
larger_array[0] = 0xBBu;
memmove(larger_array + 256, larger_array, 1024);
KUNIT_ASSERT_EQ(test, larger_array[0], 0xBBu);
KUNIT_ASSERT_EQ(test, larger_array[256], 0xBBu);
KUNIT_ASSERT_NULL(test, memchr(larger_array + 1, 0xBBu, 256 - 1));
KUNIT_ASSERT_NULL(test,
memchr(larger_array + 257, 0xBBu, ARRAY_SIZE(larger_array) - 257));
#undef TEST_OP
}
static void memset_test(struct kunit *test)
{
#define TEST_OP "memset"
struct some_bytes control = {
.data = { 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30,
0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30,
0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30,
0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30,
},
};
struct some_bytes complete = {
.data = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
},
};
struct some_bytes middle = {
.data = { 0x30, 0x30, 0x30, 0x30, 0x31, 0x31, 0x31, 0x31,
0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31,
0x31, 0x31, 0x31, 0x31, 0x30, 0x30, 0x30, 0x30,
0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30,
},
};
struct some_bytes three = {
.data = { 0x60, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30,
0x30, 0x61, 0x61, 0x30, 0x30, 0x30, 0x30, 0x30,
0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30,
0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30,
},
};
struct some_bytes after = {
.data = { 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x72,
0x72, 0x72, 0x72, 0x72, 0x72, 0x72, 0x72, 0x72,
0x72, 0x72, 0x72, 0x72, 0x72, 0x72, 0x72, 0x72,
0x72, 0x72, 0x72, 0x72, 0x72, 0x72, 0x72, 0x72,
},
};
struct some_bytes startat = {
.data = { 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30,
0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79,
0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79,
0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79, 0x79,
},
};
struct some_bytes dest = { };
int count, value;
u8 *ptr;
/* Verify static initializers. */
check(control, 0x30);
check(dest, 0);
/* Verify assignment. */
dest = control;
compare("direct assignment", dest, control);
/* Verify complete overwrite. */
memset(dest.data, 0xff, sizeof(dest.data));
compare("complete overwrite", dest, complete);
/* Verify middle overwrite. */
dest = control;
memset(dest.data + 4, 0x31, 16);
compare("middle overwrite", dest, middle);
/* Verify argument side-effects aren't repeated. */
dest = control;
ptr = dest.data;
value = 0x60;
count = 1;
memset(ptr++, value++, count++);
ptr += 8;
memset(ptr++, value++, count++);
compare("argument side-effects", dest, three);
/* Verify memset_after() */
dest = control;
memset_after(&dest, 0x72, three);
compare("memset_after()", dest, after);
/* Verify memset_startat() */
dest = control;
memset_startat(&dest, 0x79, four);
compare("memset_startat()", dest, startat);
#undef TEST_OP
}
static u8 large_src[1024];
static u8 large_dst[2048];
static const u8 large_zero[2048];
static void set_random_nonzero(struct kunit *test, u8 *byte)
{
int failed_rng = 0;
while (*byte == 0) {
get_random_bytes(byte, 1);
KUNIT_ASSERT_LT_MSG(test, failed_rng++, 100,
"Is the RNG broken?");
}
}
static void init_large(struct kunit *test)
{
if (!IS_ENABLED(CONFIG_MEMCPY_SLOW_KUNIT_TEST))
kunit_skip(test, "Slow test skipped. Enable with CONFIG_MEMCPY_SLOW_KUNIT_TEST=y");
/* Get many bit patterns. */
get_random_bytes(large_src, ARRAY_SIZE(large_src));
/* Make sure we have non-zero edges. */
set_random_nonzero(test, &large_src[0]);
set_random_nonzero(test, &large_src[ARRAY_SIZE(large_src) - 1]);
/* Explicitly zero the entire destination. */
memset(large_dst, 0, ARRAY_SIZE(large_dst));
}
/*
* Instead of an indirect function call for "copy" or a giant macro,
* use a bool to pick memcpy or memmove.
*/
static void copy_large_test(struct kunit *test, bool use_memmove)
{
init_large(test);
/* Copy a growing number of non-overlapping bytes ... */
for (int bytes = 1; bytes <= ARRAY_SIZE(large_src); bytes++) {
/* Over a shifting destination window ... */
for (int offset = 0; offset < ARRAY_SIZE(large_src); offset++) {
int right_zero_pos = offset + bytes;
int right_zero_size = ARRAY_SIZE(large_dst) - right_zero_pos;
/* Copy! */
if (use_memmove)
memmove(large_dst + offset, large_src, bytes);
else
memcpy(large_dst + offset, large_src, bytes);
/* Did we touch anything before the copy area? */
KUNIT_ASSERT_EQ_MSG(test,
memcmp(large_dst, large_zero, offset), 0,
"with size %d at offset %d", bytes, offset);
/* Did we touch anything after the copy area? */
KUNIT_ASSERT_EQ_MSG(test,
memcmp(&large_dst[right_zero_pos], large_zero, right_zero_size), 0,
"with size %d at offset %d", bytes, offset);
/* Are we byte-for-byte exact across the copy? */
KUNIT_ASSERT_EQ_MSG(test,
memcmp(large_dst + offset, large_src, bytes), 0,
"with size %d at offset %d", bytes, offset);
/* Zero out what we copied for the next cycle. */
memset(large_dst + offset, 0, bytes);
}
/* Avoid stall warnings if this loop gets slow. */
cond_resched();
}
}
static void memcpy_large_test(struct kunit *test)
{
copy_large_test(test, false);
}
static void memmove_large_test(struct kunit *test)
{
copy_large_test(test, true);
}
/*
* On the assumption that boundary conditions are going to be the most
* sensitive, instead of taking a full step (inc) each iteration,
* take single index steps for at least the first "inc"-many indexes
* from the "start" and at least the last "inc"-many indexes before
* the "end". When in the middle, take full "inc"-wide steps. For
* example, calling next_step(idx, 1, 15, 3) with idx starting at 0
* would see the following pattern: 1 2 3 4 7 10 11 12 13 14 15.
*/
static int next_step(int idx, int start, int end, int inc)
{
start += inc;
end -= inc;
if (idx < start || idx + inc > end)
inc = 1;
return idx + inc;
}
static void inner_loop(struct kunit *test, int bytes, int d_off, int s_off)
{
int left_zero_pos, left_zero_size;
int right_zero_pos, right_zero_size;
int src_pos, src_orig_pos, src_size;
int pos;
/* Place the source in the destination buffer. */
memcpy(&large_dst[s_off], large_src, bytes);
/* Copy to destination offset. */
memmove(&large_dst[d_off], &large_dst[s_off], bytes);
/* Make sure destination entirely matches. */
KUNIT_ASSERT_EQ_MSG(test, memcmp(&large_dst[d_off], large_src, bytes), 0,
"with size %d at src offset %d and dest offset %d",
bytes, s_off, d_off);
/* Calculate the expected zero spans. */
if (s_off < d_off) {
left_zero_pos = 0;
left_zero_size = s_off;
right_zero_pos = d_off + bytes;
right_zero_size = ARRAY_SIZE(large_dst) - right_zero_pos;
src_pos = s_off;
src_orig_pos = 0;
src_size = d_off - s_off;
} else {
left_zero_pos = 0;
left_zero_size = d_off;
right_zero_pos = s_off + bytes;
right_zero_size = ARRAY_SIZE(large_dst) - right_zero_pos;
src_pos = d_off + bytes;
src_orig_pos = src_pos - s_off;
src_size = right_zero_pos - src_pos;
}
/* Check non-overlapping source is unchanged.*/
KUNIT_ASSERT_EQ_MSG(test,
memcmp(&large_dst[src_pos], &large_src[src_orig_pos], src_size), 0,
"with size %d at src offset %d and dest offset %d",
bytes, s_off, d_off);
/* Check leading buffer contents are zero. */
KUNIT_ASSERT_EQ_MSG(test,
memcmp(&large_dst[left_zero_pos], large_zero, left_zero_size), 0,
"with size %d at src offset %d and dest offset %d",
bytes, s_off, d_off);
/* Check trailing buffer contents are zero. */
KUNIT_ASSERT_EQ_MSG(test,
memcmp(&large_dst[right_zero_pos], large_zero, right_zero_size), 0,
"with size %d at src offset %d and dest offset %d",
bytes, s_off, d_off);
/* Zero out everything not already zeroed.*/
pos = left_zero_pos + left_zero_size;
memset(&large_dst[pos], 0, right_zero_pos - pos);
}
static void memmove_overlap_test(struct kunit *test)
{
/*
* Running all possible offset and overlap combinations takes a
* very long time. Instead, only check up to 128 bytes offset
* into the destination buffer (which should result in crossing
* cachelines), with a step size of 1 through 7 to try to skip some
* redundancy.
*/
static const int offset_max = 128; /* less than ARRAY_SIZE(large_src); */
static const int bytes_step = 7;
static const int window_step = 7;
static const int bytes_start = 1;
static const int bytes_end = ARRAY_SIZE(large_src) + 1;
init_large(test);
/* Copy a growing number of overlapping bytes ... */
for (int bytes = bytes_start; bytes < bytes_end;
bytes = next_step(bytes, bytes_start, bytes_end, bytes_step)) {
/* Over a shifting destination window ... */
for (int d_off = 0; d_off < offset_max; d_off++) {
int s_start = max(d_off - bytes, 0);
int s_end = min_t(int, d_off + bytes, ARRAY_SIZE(large_src));
/* Over a shifting source window ... */
for (int s_off = s_start; s_off < s_end;
s_off = next_step(s_off, s_start, s_end, window_step))
inner_loop(test, bytes, d_off, s_off);
/* Avoid stall warnings. */
cond_resched();
}
}
}
static void strtomem_test(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);
}
static struct kunit_case memcpy_test_cases[] = {
KUNIT_CASE(memset_test),
KUNIT_CASE(memcpy_test),
KUNIT_CASE(memcpy_large_test),
KUNIT_CASE(memmove_test),
KUNIT_CASE(memmove_large_test),
KUNIT_CASE(memmove_overlap_test),
KUNIT_CASE(strtomem_test),
{}
};
static struct kunit_suite memcpy_test_suite = {
.name = "memcpy",
.test_cases = memcpy_test_cases,
};
kunit_test_suite(memcpy_test_suite);
MODULE_LICENSE("GPL");
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