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From:   Vitor Massaru Iha <vitor@massaru.org>
To:     kunit-dev@googlegroups.com
Cc:     linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
        brendanhiggins@google.com, keescook@chromium.org,
        davidgow@google.com, skhan@linuxfoundation.org,
        linux-kernel-mentees@lists.linuxfoundation.org
Subject: [RFC 3/3] lib: Convert test_user_copy to KUnit test
Date:   Wed, 15 Jul 2020 00:11:20 -0300
Message-Id: <20200715031120.1002016-4-vitor@massaru.org>
In-Reply-To: <20200715031120.1002016-1-vitor@massaru.org>
References: <20200715031120.1002016-1-vitor@massaru.org>
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Sender: linux-kernel-owner@vger.kernel.org
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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