[PATCH v2 33/63] lib: Introduce CONFIG_TEST_MEMCPY

Kees Cook
2021-08-18T06:24:53Z

Before changing anything about memcpy(), memmove(), and memset(), add
run-time tests to check basic behaviors for any regressions.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
lib/Kconfig.debug | 7 ++
lib/Makefile | 1 +
lib/test_memcpy.c | 264 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 272 insertions(+)
create mode 100644 lib/test_memcpy.c

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 139d362daa32..db2e8ffa6049 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2476,6 +2476,13 @@ config RATIONAL_KUNIT_TEST

If unsure, say N.

+config MEMCPY_KUNIT_TEST
+ tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS
+ depends on KUNIT
+ default KUNIT_ALL_TESTS
+ help
+ Builds unit tests for memcpy(), memmove(), and memset() functions.
+
config TEST_UDELAY
tristate "udelay test driver"
help
diff --git a/lib/Makefile b/lib/Makefile
index bd17c2bf43e1..8a4c8bdb38a2 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -77,6 +77,7 @@ obj-$(CONFIG_TEST_MIN_HEAP) += test_min_heap.o
obj-$(CONFIG_TEST_LKM) += test_module.o
obj-$(CONFIG_TEST_VMALLOC) += test_vmalloc.o
obj-$(CONFIG_TEST_OVERFLOW) += test_overflow.o
+obj-$(CONFIG_TEST_MEMCPY) += test_memcpy.o
obj-$(CONFIG_TEST_RHASHTABLE) += test_rhashtable.o
obj-$(CONFIG_TEST_SORT) += test_sort.o
obj-$(CONFIG_TEST_USER_COPY) += test_user_copy.o
diff --git a/lib/test_memcpy.c b/lib/test_memcpy.c
new file mode 100644
index 000000000000..be192b8e82b7
--- /dev/null
+++ b/lib/test_memcpy.c
@@ -0,0 +1,264 @@
+// 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 { \
+ int i; \
+ BUILD_BUG_ON(sizeof(instance.data) != 32); \
+ for (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 { \
+ int i; \
+ BUILD_BUG_ON(sizeof(one) != sizeof(two)); \
+ for (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 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);
+#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 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);
+#undef TEST_OP
+}
+
+static struct kunit_case memcpy_test_cases[] = {
+ KUNIT_CASE(memset_test),
+ KUNIT_CASE(memcpy_test),
+ KUNIT_CASE(memmove_test),
+ {}
+};
+
+static struct kunit_suite memcpy_test_suite = {
+ .name = "memcpy-test",
+ .test_cases = memcpy_test_cases,
+};
+kunit_test_suite(memcpy_test_suite);
+
+MODULE_LICENSE("GPL");
--
2.30.2