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    SubjectRe: [RFC 3/3] lib: Convert test_user_copy to KUnit test
    On Tue, Jul 14, 2020 at 8:11 PM Vitor Massaru Iha <vitor@massaru.org> 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>
    > ---
    > 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.

    Where do you delete the entry for CONFIG_TEST_USER_COPY? I don't see it here.

    > 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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