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Subject[RFC 3/3] lib: Convert test_user_copy to KUnit test
Date
This adds the conversion of the runtime tests of test_user_copy fuctions,
from `lib/test_user_copy.c`to KUnit tests.

Signed-off-by: Vitor Massaru Iha <vitor@massaru.org>
---
lib/Kconfig.debug | 17 ++
lib/Makefile | 2 +-
lib/{test_user_copy.c => user_copy_kunit.c} | 196 +++++++++-----------
3 files changed, 102 insertions(+), 113 deletions(-)
rename lib/{test_user_copy.c => user_copy_kunit.c} (55%)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 9ad9210d70a1..29558674c011 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2154,6 +2154,23 @@ config SYSCTL_KUNIT_TEST

If unsure, say N.

+config USER_COPY_KUNIT
+ tristate "KUnit Test for user/kernel boundary protections"
+ depends on KUNIT
+ depends on m
+ help
+ This builds the "test_user_copy" module that runs sanity checks
+ on the copy_to/from_user infrastructure, making sure basic
+ user/kernel boundary testing is working. If it fails to load,
+ a regression has been detected in the user/kernel memory boundary
+ protections.
+
+ 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 LIST_KUNIT_TEST
tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
depends on KUNIT
diff --git a/lib/Makefile b/lib/Makefile
index b1c42c10073b..8c145f85accc 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -78,7 +78,6 @@ obj-$(CONFIG_TEST_VMALLOC) += test_vmalloc.o
obj-$(CONFIG_TEST_OVERFLOW) += test_overflow.o
obj-$(CONFIG_TEST_RHASHTABLE) += test_rhashtable.o
obj-$(CONFIG_TEST_SORT) += test_sort.o
-obj-$(CONFIG_TEST_USER_COPY) += test_user_copy.o
obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_keys.o
obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o
obj-$(CONFIG_TEST_PRINTF) += test_printf.o
@@ -318,3 +317,4 @@ obj-$(CONFIG_OBJAGG) += objagg.o
# KUnit tests
obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o
obj-$(CONFIG_LINEAR_RANGES_TEST) += test_linear_ranges.o
+obj-$(CONFIG_USER_COPY_KUNIT) += user_copy_kunit.o
diff --git a/lib/test_user_copy.c b/lib/user_copy_kunit.c
similarity index 55%
rename from lib/test_user_copy.c
rename to lib/user_copy_kunit.c
index 5ff04d8fe971..c15bb1e997d6 100644
--- a/lib/test_user_copy.c
+++ b/lib/user_copy_kunit.c
@@ -16,6 +16,7 @@
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
+#include <kunit/test.h>

/*
* Several 32-bit architectures support 64-bit {get,put}_user() calls.
@@ -31,26 +32,16 @@
# define TEST_U64
#endif

-#define test(condition, msg, ...) \
-({ \
- int cond = (condition); \
- if (cond) \
- pr_warn("[%d] " msg "\n", __LINE__, ##__VA_ARGS__); \
- cond; \
-})
-
static bool is_zeroed(void *from, size_t size)
{
return memchr_inv(from, 0x0, size) == NULL;
}

-static int test_check_nonzero_user(char *kmem, char __user *umem, size_t size)
+static void test_check_nonzero_user(struct kunit *test, char *kmem, char __user *umem, size_t size)
{
- int ret = 0;
size_t start, end, i, zero_start, zero_end;

- if (test(size < 2 * PAGE_SIZE, "buffer too small"))
- return -EINVAL;
+ KUNIT_EXPECT_FALSE_MSG(test, size < 2 * PAGE_SIZE, "buffer too small");

/*
* We want to cross a page boundary to exercise the code more
@@ -84,7 +75,7 @@ static int test_check_nonzero_user(char *kmem, char __user *umem, size_t size)
for (i = zero_end; i < size; i += 2)
kmem[i] = 0xff;

- ret |= test(copy_to_user(umem, kmem, size),
+ KUNIT_EXPECT_FALSE_MSG(test, copy_to_user(umem, kmem, size),
"legitimate copy_to_user failed");

for (start = 0; start <= size; start++) {
@@ -93,35 +84,31 @@ static int test_check_nonzero_user(char *kmem, char __user *umem, size_t size)
int retval = check_zeroed_user(umem + start, len);
int expected = is_zeroed(kmem + start, len);

- ret |= test(retval != expected,
- "check_nonzero_user(=%d) != memchr_inv(=%d) mismatch (start=%zu, end=%zu)",
- retval, expected, start, end);
+ KUNIT_EXPECT_FALSE_MSG(test, retval != expected,
+ "check_nonzero_user(=%d) != memchr_inv(=%d) mismatch (start=%zu, end=%zu)",
+ retval, expected, start, end);
}
}
-
- return ret;
}

-static int test_copy_struct_from_user(char *kmem, char __user *umem,
+static void test_copy_struct_from_user(struct kunit *test, char *kmem, char __user *umem,
size_t size)
{
- int ret = 0;
char *umem_src = NULL, *expected = NULL;
size_t ksize, usize;

umem_src = kmalloc(size, GFP_KERNEL);
- ret = test(umem_src == NULL, "kmalloc failed");
- if (ret)
- goto out_free;
+ KUNIT_EXPECT_FALSE_MSG(test, umem_src == NULL, "kmalloc failed");

expected = kmalloc(size, GFP_KERNEL);
- ret = test(expected == NULL, "kmalloc failed");
- if (ret)
- goto out_free;
+
+ if (expected == NULL)
+ kfree(umem_src);
+ KUNIT_EXPECT_FALSE_MSG(test, expected == NULL, "kmalloc failed");

/* Fill umem with a fixed byte pattern. */
memset(umem_src, 0x3e, size);
- ret |= test(copy_to_user(umem, umem_src, size),
+ KUNIT_EXPECT_FALSE_MSG(test, copy_to_user(umem, umem_src, size),
"legitimate copy_to_user failed");

/* Check basic case -- (usize == ksize). */
@@ -131,9 +118,9 @@ static int test_copy_struct_from_user(char *kmem, char __user *umem,
memcpy(expected, umem_src, ksize);

memset(kmem, 0x0, size);
- ret |= test(copy_struct_from_user(kmem, ksize, umem, usize),
+ KUNIT_EXPECT_FALSE_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize),
"copy_struct_from_user(usize == ksize) failed");
- ret |= test(memcmp(kmem, expected, ksize),
+ KUNIT_EXPECT_FALSE_MSG(test, memcmp(kmem, expected, ksize),
"copy_struct_from_user(usize == ksize) gives unexpected copy");

/* Old userspace case -- (usize < ksize). */
@@ -144,9 +131,9 @@ static int test_copy_struct_from_user(char *kmem, char __user *umem,
memset(expected + usize, 0x0, ksize - usize);

memset(kmem, 0x0, size);
- ret |= test(copy_struct_from_user(kmem, ksize, umem, usize),
+ KUNIT_EXPECT_FALSE_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize),
"copy_struct_from_user(usize < ksize) failed");
- ret |= test(memcmp(kmem, expected, ksize),
+ KUNIT_EXPECT_FALSE_MSG(test, memcmp(kmem, expected, ksize),
"copy_struct_from_user(usize < ksize) gives unexpected copy");

/* New userspace (-E2BIG) case -- (usize > ksize). */
@@ -154,7 +141,7 @@ static int test_copy_struct_from_user(char *kmem, char __user *umem,
usize = size;

memset(kmem, 0x0, size);
- ret |= test(copy_struct_from_user(kmem, ksize, umem, usize) != -E2BIG,
+ KUNIT_EXPECT_FALSE_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize) != -E2BIG,
"copy_struct_from_user(usize > ksize) didn't give E2BIG");

/* New userspace (success) case -- (usize > ksize). */
@@ -162,24 +149,18 @@ static int test_copy_struct_from_user(char *kmem, char __user *umem,
usize = size;

memcpy(expected, umem_src, ksize);
- ret |= test(clear_user(umem + ksize, usize - ksize),
+ KUNIT_EXPECT_FALSE_MSG(test, clear_user(umem + ksize, usize - ksize),
"legitimate clear_user failed");

memset(kmem, 0x0, size);
- ret |= test(copy_struct_from_user(kmem, ksize, umem, usize),
+ KUNIT_EXPECT_FALSE_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize),
"copy_struct_from_user(usize > ksize) failed");
- ret |= test(memcmp(kmem, expected, ksize),
+ KUNIT_EXPECT_FALSE_MSG(test, memcmp(kmem, expected, ksize),
"copy_struct_from_user(usize > ksize) gives unexpected copy");
-
-out_free:
- kfree(expected);
- kfree(umem_src);
- return ret;
}

-static int __init test_user_copy_init(void)
+static void user_copy_test(struct kunit *test)
{
- int ret = 0;
char *kmem;
char __user *usermem;
char *bad_usermem;
@@ -192,16 +173,14 @@ static int __init test_user_copy_init(void)
#endif

kmem = kmalloc(PAGE_SIZE * 2, GFP_KERNEL);
- if (!kmem)
- return -ENOMEM;
+ KUNIT_EXPECT_FALSE_MSG(test, kmem == NULL, "kmalloc failed");

user_addr = vm_mmap(NULL, 0, PAGE_SIZE * 2,
PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_ANONYMOUS | MAP_PRIVATE, 0);
if (user_addr >= (unsigned long)(TASK_SIZE)) {
- pr_warn("Failed to allocate user memory\n");
kfree(kmem);
- return -ENOMEM;
+ KUNIT_FAIL(test, "Failed to allocate user memory");
}

usermem = (char __user *)user_addr;
@@ -211,29 +190,29 @@ static int __init test_user_copy_init(void)
* Legitimate usage: none of these copies should fail.
*/
memset(kmem, 0x3a, PAGE_SIZE * 2);
- ret |= test(copy_to_user(usermem, kmem, PAGE_SIZE),
- "legitimate copy_to_user failed");
+ KUNIT_EXPECT_FALSE_MSG(test, copy_to_user(usermem, kmem, PAGE_SIZE), "legitimate copy_to_user failed");
+
memset(kmem, 0x0, PAGE_SIZE);
- ret |= test(copy_from_user(kmem, usermem, PAGE_SIZE),
- "legitimate copy_from_user failed");
- ret |= test(memcmp(kmem, kmem + PAGE_SIZE, PAGE_SIZE),
- "legitimate usercopy failed to copy data");
-
-#define test_legit(size, check) \
- do { \
- val_##size = check; \
- ret |= test(put_user(val_##size, (size __user *)usermem), \
- "legitimate put_user (" #size ") failed"); \
- val_##size = 0; \
- ret |= test(get_user(val_##size, (size __user *)usermem), \
- "legitimate get_user (" #size ") failed"); \
- ret |= test(val_##size != check, \
- "legitimate get_user (" #size ") failed to do copy"); \
- if (val_##size != check) { \
- pr_info("0x%llx != 0x%llx\n", \
- (unsigned long long)val_##size, \
- (unsigned long long)check); \
- } \
+ KUNIT_EXPECT_FALSE_MSG(test, copy_from_user(kmem, usermem, PAGE_SIZE),
+ "legitimate copy_from_user failed");
+ KUNIT_EXPECT_FALSE_MSG(test, memcmp(kmem, kmem + PAGE_SIZE, PAGE_SIZE),
+ "legitimate usercopy failed to copy data");
+
+#define test_legit(size, check) \
+ do { \
+ val_##size = check; \
+ KUNIT_EXPECT_FALSE_MSG(test, put_user(val_##size, (size __user *)usermem), \
+ "legitimate put_user (" #size ") failed"); \
+ val_##size = 0; \
+ KUNIT_EXPECT_FALSE_MSG(test, get_user(val_##size, (size __user *)usermem), \
+ "legitimate get_user (" #size ") failed"); \
+ KUNIT_EXPECT_FALSE_MSG(test, val_##size != check, \
+ "legitimate get_user (" #size ") failed to do copy"); \
+ if (val_##size != check) { \
+ kunit_info(test, "0x%llx != 0x%llx\n", \
+ (unsigned long long)val_##size, \
+ (unsigned long long)check); \
+ } \
} while (0)

test_legit(u8, 0x5a);
@@ -245,9 +224,9 @@ static int __init test_user_copy_init(void)
#undef test_legit

/* Test usage of check_nonzero_user(). */
- ret |= test_check_nonzero_user(kmem, usermem, 2 * PAGE_SIZE);
+ test_check_nonzero_user(test, kmem, usermem, 2 * PAGE_SIZE);
/* Test usage of copy_struct_from_user(). */
- ret |= test_copy_struct_from_user(kmem, usermem, 2 * PAGE_SIZE);
+ test_copy_struct_from_user(test, kmem, usermem, 2 * PAGE_SIZE);

/*
* Invalid usage: none of these copies should succeed.
@@ -258,13 +237,13 @@ static int __init test_user_copy_init(void)
memset(kmem + PAGE_SIZE, 0, PAGE_SIZE);

/* Reject kernel-to-kernel copies through copy_from_user(). */
- ret |= test(!copy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE),
- PAGE_SIZE),
- "illegal all-kernel copy_from_user passed");
+ KUNIT_EXPECT_FALSE_MSG(test, !copy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE),
+ PAGE_SIZE),
+ "illegal all-kernel copy_from_user passed");

/* Destination half of buffer should have been zeroed. */
- ret |= test(memcmp(kmem + PAGE_SIZE, kmem, PAGE_SIZE),
- "zeroing failure for illegal all-kernel copy_from_user");
+ KUNIT_EXPECT_FALSE_MSG(test, memcmp(kmem + PAGE_SIZE, kmem, PAGE_SIZE),
+ "zeroing failure for illegal all-kernel copy_from_user");

#if 0
/*
@@ -273,30 +252,28 @@ static int __init test_user_copy_init(void)
* to be tested in LKDTM instead, since this test module does not
* expect to explode.
*/
- ret |= test(!copy_from_user(bad_usermem, (char __user *)kmem,
- PAGE_SIZE),
- "illegal reversed copy_from_user passed");
+ KUNIT_EXPECT_FALSE_MSG(test, !copy_from_user(bad_usermem, (char __user *)kmem,
+ PAGE_SIZE),
+ "illegal reversed copy_from_user passed");
#endif
- ret |= test(!copy_to_user((char __user *)kmem, kmem + PAGE_SIZE,
- PAGE_SIZE),
- "illegal all-kernel copy_to_user passed");
- ret |= test(!copy_to_user((char __user *)kmem, bad_usermem,
- PAGE_SIZE),
- "illegal reversed copy_to_user passed");
-
-#define test_illegal(size, check) \
- do { \
- val_##size = (check); \
- ret |= test(!get_user(val_##size, (size __user *)kmem), \
- "illegal get_user (" #size ") passed"); \
- ret |= test(val_##size != (size)0, \
- "zeroing failure for illegal get_user (" #size ")"); \
- if (val_##size != (size)0) { \
- pr_info("0x%llx != 0\n", \
- (unsigned long long)val_##size); \
- } \
- ret |= test(!put_user(val_##size, (size __user *)kmem), \
- "illegal put_user (" #size ") passed"); \
+ KUNIT_EXPECT_FALSE_MSG(test, !copy_to_user((char __user *)kmem, kmem + PAGE_SIZE, PAGE_SIZE),
+ "illegal all-kernel copy_to_user passed");
+ KUNIT_EXPECT_FALSE_MSG(test, !copy_to_user((char __user *)kmem, bad_usermem, PAGE_SIZE),
+ "illegal reversed copy_to_user passed");
+
+#define test_illegal(size, check) \
+ do { \
+ val_##size = (check); \
+ KUNIT_EXPECT_FALSE_MSG(test, !get_user(val_##size, (size __user *)kmem), \
+ "illegal get_user (" #size ") passed"); \
+ KUNIT_EXPECT_FALSE_MSG(test, val_##size != (size)0, \
+ "zeroing failure for illegal get_user (" #size ")"); \
+ if (val_##size != (size)0) { \
+ kunit_info(test, "0x%llx != 0\n", \
+ (unsigned long long)val_##size); \
+ } \
+ KUNIT_EXPECT_FALSE_MSG(test, !put_user(val_##size, (size __user *)kmem), \
+ "illegal put_user (" #size ") passed"); \
} while (0)

test_illegal(u8, 0x5a);
@@ -309,23 +286,18 @@ static int __init test_user_copy_init(void)

vm_munmap(user_addr, PAGE_SIZE * 2);
kfree(kmem);
-
- if (ret == 0) {
- pr_info("tests passed.\n");
- return 0;
- }
-
- return -EINVAL;
}

-module_init(test_user_copy_init);
-
-static void __exit test_user_copy_exit(void)
-{
- pr_info("unloaded.\n");
-}
+static struct kunit_case user_copy_test_cases[] = {
+ KUNIT_CASE(user_copy_test),
+ {}
+};

-module_exit(test_user_copy_exit);
+static struct kunit_suite user_copy_test_suite = {
+ .name = "user_copy",
+ .test_cases = user_copy_test_cases,
+};

+kunit_test_suites(&user_copy_test_suite);
MODULE_AUTHOR("Kees Cook <keescook@chromium.org>");
MODULE_LICENSE("GPL");
--
2.26.2
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