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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337// SPDX-License-Identifier: GPL-2.0-only/* * Kernel module for testing copy_to/from_user infrastructure. * * Copyright 2013 Google Inc. All Rights Reserved * * Authors: * Kees Cook <keescook@chromium.org> */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/mman.h>#include <linux/module.h>#include <linux/sched.h>#include <linux/slab.h>#include <linux/uaccess.h>#include <kunit/test.h>
/* * Several 32-bit architectures support 64-bit {get,put}_user() calls. * As there doesn't appear to be anything that can safely determine * their capability at compile-time, we just have to opt-out certain archs. */#if BITS_PER_LONG == 64 || (!(defined(CONFIG_ARM) && !defined(MMU)) && \ !defined(CONFIG_M68K) && \ !defined(CONFIG_MICROBLAZE) && \ !defined(CONFIG_NIOS2) && \ !defined(CONFIG_PPC32) && \ !defined(CONFIG_SPARC32) && \ !defined(CONFIG_SUPERH))# define TEST_U64#endif
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;}
/* Test usage of check_nonzero_user(). */static void usercopy_test_check_nonzero_user(struct kunit *test){ 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;
KUNIT_ASSERT_GE_MSG(test, size, 2 * PAGE_SIZE, "buffer too small");
/* * We want to cross a page boundary to exercise the code more * effectively. We also don't want to make the size we scan too large, * otherwise the test can take a long time and cause soft lockups. So * scan a 1024 byte region across the page boundary. */ size = 1024; start = PAGE_SIZE - (size / 2);
kmem += start; umem += start;
zero_start = size / 4; zero_end = size - zero_start;
/* * We conduct a series of check_nonzero_user() tests on a block of * memory with the following byte-pattern (trying every possible * [start,end] pair): * * [ 00 ff 00 ff ... 00 00 00 00 ... ff 00 ff 00 ] * * And we verify that check_nonzero_user() acts identically to * memchr_inv(). */
memset(kmem, 0x0, size); for (i = 1; i < zero_start; i += 2) kmem[i] = 0xff; for (i = zero_end; i < size; i += 2) kmem[i] = 0xff;
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++) { size_t len = end - start; int retval = check_zeroed_user(umem + start, len); int expected = is_zeroed(kmem + start, len);
KUNIT_ASSERT_EQ_MSG(test, retval, expected, "check_nonzero_user(=%d) != memchr_inv(=%d) mismatch (start=%zu, end=%zu)", retval, expected, start, end); } }}
/* Test usage of copy_struct_from_user(). */static void usercopy_test_copy_struct_from_user(struct kunit *test){ 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 = kunit_kmalloc(test, size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, umem_src);
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); KUNIT_ASSERT_EQ_MSG(test, copy_to_user(umem, umem_src, size), 0, "legitimate copy_to_user failed");
/* Check basic case -- (usize == ksize). */ ksize = size; usize = size;
memcpy(expected, umem_src, ksize);
memset(kmem, 0x0, size); KUNIT_EXPECT_EQ_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize), 0, "copy_struct_from_user(usize == ksize) failed"); KUNIT_EXPECT_MEMEQ_MSG(test, kmem, expected, ksize, "copy_struct_from_user(usize == ksize) gives unexpected copy");
/* Old userspace case -- (usize < ksize). */ ksize = size; usize = size / 2;
memcpy(expected, umem_src, usize); memset(expected + usize, 0x0, ksize - usize);
memset(kmem, 0x0, size); KUNIT_EXPECT_EQ_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize), 0, "copy_struct_from_user(usize < ksize) failed"); KUNIT_EXPECT_MEMEQ_MSG(test, kmem, expected, ksize, "copy_struct_from_user(usize < ksize) gives unexpected copy");
/* New userspace (-E2BIG) case -- (usize > ksize). */ ksize = size / 2; usize = size;
memset(kmem, 0x0, size); 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). */ ksize = size / 2; usize = size;
memcpy(expected, umem_src, ksize); KUNIT_EXPECT_EQ_MSG(test, clear_user(umem + ksize, usize - ksize), 0, "legitimate clear_user failed");
memset(kmem, 0x0, size); KUNIT_EXPECT_EQ_MSG(test, copy_struct_from_user(kmem, ksize, umem, usize), 0, "copy_struct_from_user(usize > ksize) failed"); KUNIT_EXPECT_MEMEQ_MSG(test, kmem, expected, ksize, "copy_struct_from_user(usize > ksize) gives unexpected copy");}
/* * Legitimate usage: none of these copies should fail. */static void usercopy_test_valid(struct kunit *test){ struct usercopy_test_priv *priv = test->priv; char __user *usermem = priv->umem; char *kmem = priv->kmem;
memset(kmem, 0x3a, PAGE_SIZE * 2); KUNIT_EXPECT_EQ_MSG(test, 0, copy_to_user(usermem, kmem, PAGE_SIZE), "legitimate copy_to_user failed"); memset(kmem, 0x0, PAGE_SIZE); KUNIT_EXPECT_EQ_MSG(test, 0, copy_from_user(kmem, usermem, PAGE_SIZE), "legitimate copy_from_user failed"); KUNIT_EXPECT_MEMEQ_MSG(test, kmem, kmem + PAGE_SIZE, PAGE_SIZE, "legitimate usercopy failed to copy data");
#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); test_legit(u16, 0x5a5b); test_legit(u32, 0x5a5b5c5d);#ifdef TEST_U64 test_legit(u64, 0x5a5b5c5d6a6b6c6d);#endif#undef test_legit}
/* * 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;
if (IS_ENABLED(CONFIG_ALTERNATE_USER_ADDRESS_SPACE) || !IS_ENABLED(CONFIG_MMU)) { kunit_skip(test, "Testing for kernel/userspace address confusion is only sensible on architectures with a shared address space"); return; }
/* 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(). */ 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. */ KUNIT_EXPECT_MEMEQ_MSG(test, kmem + PAGE_SIZE, kmem, PAGE_SIZE, "zeroing failure for illegal all-kernel copy_from_user");
#if 0 /* * When running with SMAP/PAN/etc, this will Oops the kernel * due to the zeroing of userspace memory on failure. This needs * to be tested in LKDTM instead, since this test module does not * expect to explode. */ KUNIT_EXPECT_NE_MSG(test, copy_from_user(bad_usermem, (char __user *)kmem, PAGE_SIZE), 0, "illegal reversed copy_from_user passed");#endif KUNIT_EXPECT_NE_MSG(test, copy_to_user((char __user *)kmem, kmem + PAGE_SIZE, PAGE_SIZE), 0, "illegal all-kernel copy_to_user passed");
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 { \ 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); test_illegal(u16, 0x5a5b); test_illegal(u32, 0x5a5b5c5d);#ifdef TEST_U64 test_illegal(u64, 0x5a5b5c5d6a6b6c6d);#endif#undef test_illegal}
static int usercopy_test_init(struct kunit *test){ struct usercopy_test_priv *priv; unsigned long user_addr;
if (!IS_ENABLED(CONFIG_MMU)) { kunit_skip(test, "Userspace allocation testing not available on non-MMU systems"); 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;
priv->kmem = kunit_kmalloc(test, priv->size, GFP_KERNEL); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->kmem);
user_addr = kunit_vm_mmap(test, NULL, 0, priv->size, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_ANONYMOUS | MAP_PRIVATE, 0); KUNIT_ASSERT_NE_MSG(test, user_addr, 0, "Could not create userspace mm"); KUNIT_ASSERT_LT_MSG(test, user_addr, (unsigned long)TASK_SIZE, "Failed to allocate user memory"); priv->umem = (char __user *)user_addr;
return 0;}
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@kernel.org>");MODULE_DESCRIPTION("Kernel module for testing copy_to/from_user infrastructure");MODULE_LICENSE("GPL");