On Tue, 11 Jun 2024 at 05:33, Kees Cook <kees@xxxxxxxxxx> wrote: > > Convert the runtime tests of hardened usercopy to standard KUnit tests. > > Co-developed-by: Vitor Massaru Iha <vitor@xxxxxxxxxxx> > Signed-off-by: Vitor Massaru Iha <vitor@xxxxxxxxxxx> > Link: https://lore.kernel.org/r/20200721174654.72132-1-vitor@xxxxxxxxxxx > Tested-by: Ivan Orlov <ivan.orlov0322@xxxxxxxxx> > Signed-off-by: Kees Cook <kees@xxxxxxxxxx> > --- This looks good, particularly with the x86 fix applied. It's still hanging on m68k -- I think at the 'illegal reversed copy_to_user passed' test -- but I'll admit to not having tried to debug it further. One other (set of) notes below about using KUNIT_EXPECT_MEMEQ_MSG(), otherwise (assuming the m68k stuff isn't actually a regression, which I haven't tested but I imagine is unlikely), Reviewed-by: David Gow <davidgow@xxxxxxxxxx> Thanks, -- David > MAINTAINERS | 1 + > lib/Kconfig.debug | 21 +- > lib/Makefile | 2 +- > lib/{test_user_copy.c => usercopy_kunit.c} | 273 ++++++++++----------- > 4 files changed, 142 insertions(+), 155 deletions(-) > rename lib/{test_user_copy.c => usercopy_kunit.c} (47%) > > diff --git a/MAINTAINERS b/MAINTAINERS > index 8754ac2c259d..0cd171ec6010 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -11962,6 +11962,7 @@ F: arch/*/configs/hardening.config > F: include/linux/overflow.h > F: include/linux/randomize_kstack.h > F: kernel/configs/hardening.config > +F: lib/usercopy_kunit.c > F: mm/usercopy.c > K: \b(add|choose)_random_kstack_offset\b > K: \b__check_(object_size|heap_object)\b > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 59b6765d86b8..561e346f5cb0 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -2505,18 +2505,6 @@ 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 > @@ -2814,6 +2802,15 @@ config SIPHASH_KUNIT_TEST > This is intended to help people writing architecture-specific > optimized versions. If unsure, say N. > > +config USERCOPY_KUNIT_TEST > + tristate "KUnit Test for user/kernel boundary protections" > + depends on KUNIT > + default KUNIT_ALL_TESTS > + help > + This builds the "usercopy_kunit" module that runs sanity checks > + on the copy_to/from_user infrastructure, making sure basic > + user/kernel boundary testing is working. > + > config TEST_UDELAY > tristate "udelay test driver" > help > diff --git a/lib/Makefile b/lib/Makefile > index 3b1769045651..fae5cc67b95a 100644 > --- a/lib/Makefile > +++ b/lib/Makefile > @@ -78,7 +78,6 @@ obj-$(CONFIG_TEST_LKM) += test_module.o > obj-$(CONFIG_TEST_VMALLOC) += test_vmalloc.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_DYNAMIC_DEBUG) += test_dynamic_debug.o > @@ -388,6 +387,7 @@ CFLAGS_fortify_kunit.o += $(call cc-disable-warning, stringop-truncation) > CFLAGS_fortify_kunit.o += $(DISABLE_STRUCTLEAK_PLUGIN) > obj-$(CONFIG_FORTIFY_KUNIT_TEST) += fortify_kunit.o > obj-$(CONFIG_SIPHASH_KUNIT_TEST) += siphash_kunit.o > +obj-$(CONFIG_USERCOPY_KUNIT_TEST) += usercopy_kunit.o > > obj-$(CONFIG_GENERIC_LIB_DEVMEM_IS_ALLOWED) += devmem_is_allowed.o > > diff --git a/lib/test_user_copy.c b/lib/usercopy_kunit.c > similarity index 47% > rename from lib/test_user_copy.c > rename to lib/usercopy_kunit.c > index 5ff04d8fe971..f1689f2c5c7b 100644 > --- a/lib/test_user_copy.c > +++ b/lib/usercopy_kunit.c > @@ -15,7 +15,7 @@ > #include <linux/sched.h> > #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 +31,27 @@ > # define TEST_U64 > #endif > > -#define test(condition, msg, ...) \ > -({ \ > - int cond = (condition); \ > - if (cond) \ > - pr_warn("[%d] " msg "\n", __LINE__, ##__VA_ARGS__); \ > - cond; \ > -}) > +struct usercopy_test_priv { > + char *kmem; > + char __user *umem; > + size_t size; > +}; > > 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) > +/* Test usage of check_nonzero_user(). */ > +static void usercopy_test_check_nonzero_user(struct kunit *test) > { > - int ret = 0; > size_t start, end, i, zero_start, zero_end; > + struct usercopy_test_priv *priv = test->priv; > + char __user *umem = priv->umem; > + char *kmem = priv->kmem; > + size_t size = priv->size; > > - if (test(size < 2 * PAGE_SIZE, "buffer too small")) > - return -EINVAL; > + KUNIT_ASSERT_GE_MSG(test, size, 2 * PAGE_SIZE, "buffer too small"); > > /* > * We want to cross a page boundary to exercise the code more > @@ -84,8 +85,8 @@ 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), > - "legitimate copy_to_user failed"); > + KUNIT_EXPECT_EQ_MSG(test, copy_to_user(umem, kmem, size), 0, > + "legitimate copy_to_user failed"); > > for (start = 0; start <= size; start++) { > for (end = start; end <= size; end++) { > @@ -93,35 +94,32 @@ 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_EQ_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, > - size_t size) > +/* Test usage of copy_struct_from_user(). */ > +static void usercopy_test_copy_struct_from_user(struct kunit *test) > { > - int ret = 0; > char *umem_src = NULL, *expected = NULL; > + struct usercopy_test_priv *priv = test->priv; > + char __user *umem = priv->umem; > + char *kmem = priv->kmem; > + size_t size = priv->size; > size_t ksize, usize; > > - umem_src = kmalloc(size, GFP_KERNEL); > - ret = test(umem_src == NULL, "kmalloc failed"); > - if (ret) > - goto out_free; > + umem_src = kunit_kmalloc(test, size, GFP_KERNEL); > + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, umem_src); > > - expected = kmalloc(size, GFP_KERNEL); > - ret = test(expected == NULL, "kmalloc failed"); > - if (ret) > - goto out_free; > + expected = kunit_kmalloc(test, size, GFP_KERNEL); > + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, expected); > > /* Fill umem with a fixed byte pattern. */ > memset(umem_src, 0x3e, size); > - ret |= test(copy_to_user(umem, umem_src, size), > + KUNIT_ASSERT_EQ_MSG(test, copy_to_user(umem, umem_src, size), 0, > "legitimate copy_to_user failed"); > > /* Check basic case -- (usize == ksize). */ > @@ -131,9 +129,9 @@ 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_EQ_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize), 0, > "copy_struct_from_user(usize == ksize) failed"); > - ret |= test(memcmp(kmem, expected, ksize), > + KUNIT_EXPECT_EQ_MSG(test, memcmp(kmem, expected, ksize), 0, > "copy_struct_from_user(usize == ksize) gives unexpected copy"); Should we use KUNIT_EXPECT_MEMEQ_MSG() here, rather than memcmp()? That'll print a nice hexdump of the difference. > > /* Old userspace case -- (usize < ksize). */ > @@ -144,9 +142,9 @@ 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_EQ_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize), 0, > "copy_struct_from_user(usize < ksize) failed"); > - ret |= test(memcmp(kmem, expected, ksize), > + KUNIT_EXPECT_EQ_MSG(test, memcmp(kmem, expected, ksize), 0, > "copy_struct_from_user(usize < ksize) gives unexpected copy"); Again, can we use KUNIT_EXPECT_MEMEQ_MSG() here, rather than memcmp()? > /* New userspace (-E2BIG) case -- (usize > ksize). */ > @@ -154,7 +152,7 @@ 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_EQ_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). */ > @@ -162,78 +160,46 @@ 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_EQ_MSG(test, clear_user(umem + ksize, usize - ksize), 0, > "legitimate clear_user failed"); > > memset(kmem, 0x0, size); > - ret |= test(copy_struct_from_user(kmem, ksize, umem, usize), > + KUNIT_EXPECT_EQ_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize), 0, > "copy_struct_from_user(usize > ksize) failed"); > - ret |= test(memcmp(kmem, expected, ksize), > + KUNIT_EXPECT_EQ_MSG(test, memcmp(kmem, expected, ksize), 0, > "copy_struct_from_user(usize > ksize) gives unexpected copy"); Another place to use KUNIT_EXPECT_MEMEQ_MSG()? > - > -out_free: > - kfree(expected); > - kfree(umem_src); > - return ret; > } > > -static int __init test_user_copy_init(void) > +/* > + * Legitimate usage: none of these copies should fail. > + */ > +static void usercopy_test_valid(struct kunit *test) > { > - int ret = 0; > - char *kmem; > - char __user *usermem; > - char *bad_usermem; > - unsigned long user_addr; > - u8 val_u8; > - u16 val_u16; > - u32 val_u32; > -#ifdef TEST_U64 > - u64 val_u64; > -#endif > - > - kmem = kmalloc(PAGE_SIZE * 2, GFP_KERNEL); > - if (!kmem) > - return -ENOMEM; > + struct usercopy_test_priv *priv = test->priv; > + char __user *usermem = priv->umem; > + char *kmem = priv->kmem; > > - 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; > - } > - > - usermem = (char __user *)user_addr; > - bad_usermem = (char *)user_addr; > - > - /* > - * 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_EQ_MSG(test, 0, 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_EQ_MSG(test, 0, copy_from_user(kmem, usermem, PAGE_SIZE), > + "legitimate copy_from_user failed"); > + KUNIT_EXPECT_EQ_MSG(test, 0, memcmp(kmem, kmem + PAGE_SIZE, PAGE_SIZE), > + "legitimate usercopy failed to copy data"); KUNIT_EXPECT_MEMEQ_MSG()? > + > +#define test_legit(size, check) \ > + do { \ > + size val_##size = (check); \ > + KUNIT_EXPECT_EQ_MSG(test, 0, \ > + put_user(val_##size, (size __user *)usermem), \ > + "legitimate put_user (" #size ") failed"); \ > + val_##size = 0; \ > + KUNIT_EXPECT_EQ_MSG(test, 0, \ > + get_user(val_##size, (size __user *)usermem), \ > + "legitimate get_user (" #size ") failed"); \ > + KUNIT_EXPECT_EQ_MSG(test, val_##size, check, \ > + "legitimate get_user (" #size ") failed to do copy"); \ > } while (0) > > test_legit(u8, 0x5a); > @@ -243,27 +209,30 @@ static int __init test_user_copy_init(void) > test_legit(u64, 0x5a5b5c5d6a6b6c6d); > #endif > #undef test_legit > +} > > - /* Test usage of check_nonzero_user(). */ > - ret |= test_check_nonzero_user(kmem, usermem, 2 * PAGE_SIZE); > - /* Test usage of copy_struct_from_user(). */ > - ret |= test_copy_struct_from_user(kmem, usermem, 2 * PAGE_SIZE); > - > - /* > - * Invalid usage: none of these copies should succeed. > - */ > +/* > + * Invalid usage: none of these copies should succeed. > + */ > +static void usercopy_test_invalid(struct kunit *test) > +{ > + struct usercopy_test_priv *priv = test->priv; > + char __user *usermem = priv->umem; > + char *bad_usermem = (char *)usermem; > + char *kmem = priv->kmem; > + u64 *kmem_u64 = (u64 *)kmem; > > /* Prepare kernel memory with check values. */ > memset(kmem, 0x5a, PAGE_SIZE); > 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), > + KUNIT_EXPECT_NE_MSG(test, copy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE), > + PAGE_SIZE), 0, > "illegal all-kernel copy_from_user passed"); > > /* Destination half of buffer should have been zeroed. */ > - ret |= test(memcmp(kmem + PAGE_SIZE, kmem, PAGE_SIZE), > + KUNIT_EXPECT_EQ_MSG(test, memcmp(kmem + PAGE_SIZE, kmem, PAGE_SIZE), 0, > "zeroing failure for illegal all-kernel copy_from_user"); KUNIT_EXPECT_MEMEQ_MSG()? > > #if 0 > @@ -273,30 +242,31 @@ 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), > + KUNIT_EXPECT_NE_MSG(test, copy_from_user(bad_usermem, (char __user *)kmem, > + PAGE_SIZE), 0, > "illegal reversed copy_from_user passed"); > #endif > - ret |= test(!copy_to_user((char __user *)kmem, kmem + PAGE_SIZE, > - PAGE_SIZE), > + KUNIT_EXPECT_NE_MSG(test, copy_to_user((char __user *)kmem, kmem + PAGE_SIZE, > + PAGE_SIZE), 0, > "illegal all-kernel copy_to_user passed"); > - ret |= test(!copy_to_user((char __user *)kmem, bad_usermem, > - PAGE_SIZE), > + KUNIT_EXPECT_NE_MSG(test, copy_to_user((char __user *)kmem, bad_usermem, > + PAGE_SIZE), 0, > "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"); \ > +#define test_illegal(size, check) \ > + do { \ > + size val_##size = (check); \ > + /* get_user() */ \ > + KUNIT_EXPECT_NE_MSG(test, get_user(val_##size, (size __user *)kmem), 0, \ > + "illegal get_user (" #size ") passed"); \ > + KUNIT_EXPECT_EQ_MSG(test, val_##size, 0, \ > + "zeroing failure for illegal get_user (" #size ")"); \ > + /* put_user() */ \ > + *kmem_u64 = 0xF09FA4AFF09FA4AF; \ > + KUNIT_EXPECT_NE_MSG(test, put_user(val_##size, (size __user *)kmem), 0, \ > + "illegal put_user (" #size ") passed"); \ > + KUNIT_EXPECT_EQ_MSG(test, *kmem_u64, 0xF09FA4AFF09FA4AF, \ > + "illegal put_user (" #size ") wrote to kernel memory!"); \ > } while (0) > > test_illegal(u8, 0x5a); > @@ -306,26 +276,45 @@ static int __init test_user_copy_init(void) > test_illegal(u64, 0x5a5b5c5d6a6b6c6d); > #endif > #undef test_illegal > +} > > - vm_munmap(user_addr, PAGE_SIZE * 2); > - kfree(kmem); > +static int usercopy_test_init(struct kunit *test) > +{ > + struct usercopy_test_priv *priv; > + unsigned long user_addr; > > - if (ret == 0) { > - pr_info("tests passed.\n"); > - return 0; > - } > + priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL); > + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv); > + test->priv = priv; > + priv->size = PAGE_SIZE * 2; > > - return -EINVAL; > -} > + priv->kmem = kunit_kmalloc(test, priv->size, GFP_KERNEL); > + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->kmem); > > -module_init(test_user_copy_init); > + user_addr = kunit_vm_mmap(test, NULL, 0, priv->size, > + PROT_READ | PROT_WRITE | PROT_EXEC, > + MAP_ANONYMOUS | MAP_PRIVATE, 0); > + KUNIT_ASSERT_LT_MSG(test, user_addr, (unsigned long)TASK_SIZE, > + "Failed to allocate user memory"); > + priv->umem = (char __user *)user_addr; > > -static void __exit test_user_copy_exit(void) > -{ > - pr_info("unloaded.\n"); > + return 0; > } > > -module_exit(test_user_copy_exit); > - > -MODULE_AUTHOR("Kees Cook <keescook@xxxxxxxxxxxx>"); > +static struct kunit_case usercopy_test_cases[] = { > + KUNIT_CASE(usercopy_test_valid), > + KUNIT_CASE(usercopy_test_invalid), > + KUNIT_CASE(usercopy_test_check_nonzero_user), > + KUNIT_CASE(usercopy_test_copy_struct_from_user), > + {} > +}; > + > +static struct kunit_suite usercopy_test_suite = { > + .name = "usercopy", > + .init = usercopy_test_init, > + .test_cases = usercopy_test_cases, > +}; > + > +kunit_test_suites(&usercopy_test_suite); > +MODULE_AUTHOR("Kees Cook <kees@xxxxxxxxxx>"); > MODULE_LICENSE("GPL"); > -- > 2.34.1 >
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