1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
|
/*
* Kernel module for testing copy_to/from_user infrastructure.
*
* Copyright 2013 Google Inc. All Rights Reserved
*
* Authors:
* Kees Cook <keescook@chromium.org>
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#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>
#define test(condition, msg) \
({ \
int cond = (condition); \
if (cond) \
pr_warn("%s\n", msg); \
cond; \
})
static int __init test_user_copy_init(void)
{
int ret = 0;
char *kmem;
char __user *usermem;
char *bad_usermem;
unsigned long user_addr;
unsigned long value = 0x5A;
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 should fail. */
ret |= test(copy_from_user(kmem, usermem, PAGE_SIZE),
"legitimate copy_from_user failed");
ret |= test(copy_to_user(usermem, kmem, PAGE_SIZE),
"legitimate copy_to_user failed");
ret |= test(get_user(value, (unsigned long __user *)usermem),
"legitimate get_user failed");
ret |= test(put_user(value, (unsigned long __user *)usermem),
"legitimate put_user failed");
/* Invalid usage: none of these should succeed. */
ret |= test(!copy_from_user(kmem, (char __user *)(kmem + PAGE_SIZE),
PAGE_SIZE),
"illegal all-kernel copy_from_user passed");
ret |= test(!copy_from_user(bad_usermem, (char __user *)kmem,
PAGE_SIZE),
"illegal reversed copy_from_user passed");
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");
ret |= test(!get_user(value, (unsigned long __user *)kmem),
"illegal get_user passed");
ret |= test(!put_user(value, (unsigned long __user *)kmem),
"illegal put_user passed");
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");
|
