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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /lib/test_user_copy.c | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | lib/test_user_copy.c | 331 |
1 files changed, 331 insertions, 0 deletions
diff --git a/lib/test_user_copy.c b/lib/test_user_copy.c new file mode 100644 index 0000000000..5ff04d8fe9 --- /dev/null +++ b/lib/test_user_copy.c @@ -0,0 +1,331 @@ +// 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 <linux/vmalloc.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_SUPERH)) +# 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) +{ + int ret = 0; + size_t start, end, i, zero_start, zero_end; + + if (test(size < 2 * PAGE_SIZE, "buffer too small")) + return -EINVAL; + + /* + * 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; + + ret |= test(copy_to_user(umem, kmem, size), + "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); + + ret |= 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) +{ + 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; + + expected = kmalloc(size, GFP_KERNEL); + ret = test(expected == NULL, "kmalloc failed"); + if (ret) + goto out_free; + + /* Fill umem with a fixed byte pattern. */ + memset(umem_src, 0x3e, size); + ret |= test(copy_to_user(umem, umem_src, size), + "legitimate copy_to_user failed"); + + /* Check basic case -- (usize == ksize). */ + ksize = size; + usize = size; + + memcpy(expected, umem_src, ksize); + + memset(kmem, 0x0, size); + ret |= test(copy_struct_from_user(kmem, ksize, umem, usize), + "copy_struct_from_user(usize == ksize) failed"); + ret |= test(memcmp(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); + ret |= test(copy_struct_from_user(kmem, ksize, umem, usize), + "copy_struct_from_user(usize < ksize) failed"); + ret |= test(memcmp(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); + ret |= 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); + ret |= 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), + "copy_struct_from_user(usize > ksize) failed"); + ret |= 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) +{ + 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; + + 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"); + 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); \ + } \ + } 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 + + /* 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. + */ + + /* 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), + "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"); + +#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. + */ + ret |= 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"); \ + } 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 + + 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"); +} + +module_exit(test_user_copy_exit); + +MODULE_AUTHOR("Kees Cook <keescook@chromium.org>"); +MODULE_LICENSE("GPL"); |