Re: [PATCH v3] lib: Convert test_user_copy to KUnit test

On Tue, Jul 21, 2020 at 02:46:54PM -0300, Vitor Massaru Iha wrote:

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

v2: * splitted patch in 3: - Allows to install and load modules in root filesystem; - Provides an userspace memory context when tests are compiled as module; - Convert test_user_copy to KUnit test; * removed entry for CONFIG_TEST_USER_COPY; * replaced pr_warn to KUNIT_EXPECT_FALSE_MSG in test macro to decrease the diff; v3: * rebased with last kunit branch * Please apply this commit from kunit-fixes: 3f37d14b8a3152441f36b6bc74000996679f0998 And these from patchwork: https://patchwork.kernel.org/patch/11676331/ https://patchwork.kernel.org/patch/11676335/

---

lib/Kconfig.debug | 28 ++++++++------ lib/Makefile | 2 +- lib/{test_user_copy.c => user_copy_kunit.c} | 42 +++++++++------------ 3 files changed, 35 insertions(+), 37 deletions(-) rename lib/{test_user_copy.c => user_copy_kunit.c} (91%)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 9ad9210d70a1..f699a3624ae7 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -2078,18 +2078,6 @@ config TEST_VMALLOC

 If unsure, say N.

-config TEST_USER_COPY

• tristate "Test user/kernel boundary protections"
• 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.
  

•  If unsure, say N.
  

config TEST_BPF tristate "Test BPF filter functionality" depends on m && NET @@ -2154,6 +2142,22 @@ 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 "user_copy_kunit" 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 91% rename from lib/test_user_copy.c rename to lib/user_copy_kunit.c index 5ff04d8fe971..a10ddd15b4cd 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.

@@ -35,7 +36,7 @@ ({ \ int cond = (condition); \ if (cond) \

• pr_warn("[%d] " msg "\n", __LINE__, ##__VA_ARGS__);	\
  

• KUNIT_EXPECT_FALSE_MSG(test, cond, msg, ##__VA_ARGS__);	\
  

I'm surprised any of this compiles with both a macro and arg named "test". :) Can you change the arg to something with more clarity? "context" or "kunit" seems better.

cond; \ })

@@ -44,7 +45,7 @@ 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 int 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; @@ -102,7 +103,7 @@ static int test_check_nonzero_user(char *kmem, char __user *umem, size_t size) return ret; }

-static int test_copy_struct_from_user(char *kmem, char __user *umem, +static int test_copy_struct_from_user(struct kunit *test, char *kmem, char __user *umem, size_t size) { int ret = 0; @@ -177,7 +178,7 @@ static int test_copy_struct_from_user(char *kmem, char __user *umem, return ret; }

-static int __init test_user_copy_init(void) +static void user_copy_test(struct kunit *test) { int ret = 0; char *kmem; @@ -192,16 +193,14 @@ 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");

This would need to be an ASSERT, yes?

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");
  

  }

Why FAIL instead of ASSERT?

usermem = (char __user *)user_addr; @@ -245,9 +244,9 @@ 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);

• ret |= 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);

• ret |= test_copy_struct_from_user(test, kmem, usermem, 2 * PAGE_SIZE);

  /*

  • Invalid usage: none of these copies should succeed.

@@ -309,23 +308,18 @@ 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;

Does KUnit provide a end-of-test summary now?

}

-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");

base-commit: d43c7fb05765152d4d4a39a8ef957c4ea14d8847

2.26.2

Otherwise, yes, looking good.