blob: 0ecef3e4690eb484a2e548ce49374145a776ef62 [file] [log] [blame]
Kees Cook3e2a4c12014-01-23 15:54:38 -08001/*
2 * Kernel module for testing copy_to/from_user infrastructure.
3 *
4 * Copyright 2013 Google Inc. All Rights Reserved
5 *
6 * Authors:
7 * Kees Cook <keescook@chromium.org>
8 *
9 * This software is licensed under the terms of the GNU General Public
10 * License version 2, as published by the Free Software Foundation, and
11 * may be copied, distributed, and modified under those terms.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 */
18
19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#include <linux/mman.h>
22#include <linux/module.h>
23#include <linux/sched.h>
24#include <linux/slab.h>
25#include <linux/uaccess.h>
26#include <linux/vmalloc.h>
27
28#define test(condition, msg) \
29({ \
30 int cond = (condition); \
31 if (cond) \
32 pr_warn("%s\n", msg); \
33 cond; \
34})
35
36static int __init test_user_copy_init(void)
37{
38 int ret = 0;
39 char *kmem;
40 char __user *usermem;
41 char *bad_usermem;
42 unsigned long user_addr;
43 unsigned long value = 0x5A;
44
45 kmem = kmalloc(PAGE_SIZE * 2, GFP_KERNEL);
46 if (!kmem)
47 return -ENOMEM;
48
49 user_addr = vm_mmap(NULL, 0, PAGE_SIZE * 2,
50 PROT_READ | PROT_WRITE | PROT_EXEC,
51 MAP_ANONYMOUS | MAP_PRIVATE, 0);
52 if (user_addr >= (unsigned long)(TASK_SIZE)) {
53 pr_warn("Failed to allocate user memory\n");
54 kfree(kmem);
55 return -ENOMEM;
56 }
57
58 usermem = (char __user *)user_addr;
59 bad_usermem = (char *)user_addr;
60
61 /* Legitimate usage: none of these should fail. */
62 ret |= test(copy_from_user(kmem, usermem, PAGE_SIZE),
63 "legitimate copy_from_user failed");
64 ret |= test(copy_to_user(usermem, kmem, PAGE_SIZE),
65 "legitimate copy_to_user failed");
66 ret |= test(get_user(value, (unsigned long __user *)usermem),
67 "legitimate get_user failed");
68 ret |= test(put_user(value, (unsigned long __user *)usermem),
69 "legitimate put_user failed");
70
71 /* Invalid usage: none of these should succeed. */
72 ret |= test(!copy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE),
73 PAGE_SIZE),
74 "illegal all-kernel copy_from_user passed");
75 ret |= test(!copy_from_user(bad_usermem, (char __user *)kmem,
76 PAGE_SIZE),
77 "illegal reversed copy_from_user passed");
78 ret |= test(!copy_to_user((char __user *)kmem, kmem + PAGE_SIZE,
79 PAGE_SIZE),
80 "illegal all-kernel copy_to_user passed");
81 ret |= test(!copy_to_user((char __user *)kmem, bad_usermem,
82 PAGE_SIZE),
83 "illegal reversed copy_to_user passed");
84 ret |= test(!get_user(value, (unsigned long __user *)kmem),
85 "illegal get_user passed");
86 ret |= test(!put_user(value, (unsigned long __user *)kmem),
87 "illegal put_user passed");
88
89 vm_munmap(user_addr, PAGE_SIZE * 2);
90 kfree(kmem);
91
92 if (ret == 0) {
93 pr_info("tests passed.\n");
94 return 0;
95 }
96
97 return -EINVAL;
98}
99
100module_init(test_user_copy_init);
101
102static void __exit test_user_copy_exit(void)
103{
104 pr_info("unloaded.\n");
105}
106
107module_exit(test_user_copy_exit);
108
109MODULE_AUTHOR("Kees Cook <keescook@chromium.org>");
110MODULE_LICENSE("GPL");