1 /*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License as published by
4 * the Free Software Foundation; either version 2 of the License, or
5 * (at your option) any later version.
6 *
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
11 *
12 * You should have received a copy of the GNU General Public License
13 * along with this program; if not, write to the Free Software
14 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
15 *
16 * Copyright (C) IBM Corporation, 2010
17 *
18 * Author: Anton Blanchard <anton@au.ibm.com>
19 */
20 #include <linux/export.h>
21 #include <linux/compiler.h>
22 #include <linux/types.h>
23 #include <asm/checksum.h>
24 #include <asm/uaccess.h>
25
csum_and_copy_from_user(const void __user * src,void * dst,int len,__wsum sum,int * err_ptr)26 __wsum csum_and_copy_from_user(const void __user *src, void *dst,
27 int len, __wsum sum, int *err_ptr)
28 {
29 unsigned int csum;
30
31 might_sleep();
32
33 *err_ptr = 0;
34
35 if (!len) {
36 csum = 0;
37 goto out;
38 }
39
40 if (unlikely((len < 0) || !access_ok(VERIFY_READ, src, len))) {
41 *err_ptr = -EFAULT;
42 csum = (__force unsigned int)sum;
43 goto out;
44 }
45
46 csum = csum_partial_copy_generic((void __force *)src, dst,
47 len, sum, err_ptr, NULL);
48
49 if (unlikely(*err_ptr)) {
50 int missing = __copy_from_user(dst, src, len);
51
52 if (missing) {
53 memset(dst + len - missing, 0, missing);
54 *err_ptr = -EFAULT;
55 } else {
56 *err_ptr = 0;
57 }
58
59 csum = csum_partial(dst, len, sum);
60 }
61
62 out:
63 return (__force __wsum)csum;
64 }
65 EXPORT_SYMBOL(csum_and_copy_from_user);
66
csum_and_copy_to_user(const void * src,void __user * dst,int len,__wsum sum,int * err_ptr)67 __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len,
68 __wsum sum, int *err_ptr)
69 {
70 unsigned int csum;
71
72 might_sleep();
73
74 *err_ptr = 0;
75
76 if (!len) {
77 csum = 0;
78 goto out;
79 }
80
81 if (unlikely((len < 0) || !access_ok(VERIFY_WRITE, dst, len))) {
82 *err_ptr = -EFAULT;
83 csum = -1; /* invalid checksum */
84 goto out;
85 }
86
87 csum = csum_partial_copy_generic(src, (void __force *)dst,
88 len, sum, NULL, err_ptr);
89
90 if (unlikely(*err_ptr)) {
91 csum = csum_partial(src, len, sum);
92
93 if (copy_to_user(dst, src, len)) {
94 *err_ptr = -EFAULT;
95 csum = -1; /* invalid checksum */
96 }
97 }
98
99 out:
100 return (__force __wsum)csum;
101 }
102 EXPORT_SYMBOL(csum_and_copy_to_user);
103