lib: Introduce CONFIG_MEMCPY_KUNIT_TEST

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>

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index d566f601780f078cb44343473f943f84cc7a5634..98426bd7860819657a075220a28035c5d080b9de 100644 (file)
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2452,6 +2452,17 @@ 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.
+         For more information on KUnit and unit tests in general please refer
+         to the KUnit documentation in Documentation/dev-tools/kunit/.
+
+         If unsure, say N.
+
 config TEST_UDELAY
        tristate "udelay test driver"
        help

diff --git a/lib/Makefile b/lib/Makefile
index bd17c2bf43e170aacd3bbb3c0f0aaafd38f30bd4..2cfd33917ad5265054053fd550793ae2e610f39c 100644 (file)
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -358,6 +358,7 @@ obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o
 obj-$(CONFIG_BITS_TEST) += test_bits.o
 obj-$(CONFIG_CMDLINE_KUNIT_TEST) += cmdline_kunit.o
 obj-$(CONFIG_SLUB_KUNIT_TEST) += slub_kunit.o
+obj-$(CONFIG_MEMCPY_KUNIT_TEST) += memcpy_kunit.o
 
 obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o
 

diff --git a/lib/memcpy_kunit.c b/lib/memcpy_kunit.c
new file mode 100644 (file)
index 0000000..8b2109b
--- /dev/null
+++ b/lib/memcpy_kunit.c
@@ -0,0 +1,265 @@
+// 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_cases = memcpy_test_cases,
+};
+
+kunit_test_suite(memcpy_test_suite);
+
+MODULE_LICENSE("GPL");