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1a59d1b8 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
fdd374b6 | 2 | /* |
fdd374b6 AB |
3 | * |
4 | * Copyright (C) IBM Corporation, 2010 | |
5 | * | |
6 | * Author: Anton Blanchard <anton@au.ibm.com> | |
7 | */ | |
4b16f8e2 | 8 | #include <linux/export.h> |
fdd374b6 AB |
9 | #include <linux/compiler.h> |
10 | #include <linux/types.h> | |
11 | #include <asm/checksum.h> | |
7c0f6ba6 | 12 | #include <linux/uaccess.h> |
fdd374b6 AB |
13 | |
14 | __wsum csum_and_copy_from_user(const void __user *src, void *dst, | |
15 | int len, __wsum sum, int *err_ptr) | |
16 | { | |
17 | unsigned int csum; | |
18 | ||
19 | might_sleep(); | |
de78a9c4 | 20 | allow_read_from_user(src, len); |
fdd374b6 AB |
21 | |
22 | *err_ptr = 0; | |
23 | ||
24 | if (!len) { | |
25 | csum = 0; | |
26 | goto out; | |
27 | } | |
28 | ||
96d4f267 | 29 | if (unlikely((len < 0) || !access_ok(src, len))) { |
fdd374b6 AB |
30 | *err_ptr = -EFAULT; |
31 | csum = (__force unsigned int)sum; | |
32 | goto out; | |
33 | } | |
34 | ||
35 | csum = csum_partial_copy_generic((void __force *)src, dst, | |
36 | len, sum, err_ptr, NULL); | |
37 | ||
38 | if (unlikely(*err_ptr)) { | |
39 | int missing = __copy_from_user(dst, src, len); | |
40 | ||
41 | if (missing) { | |
42 | memset(dst + len - missing, 0, missing); | |
43 | *err_ptr = -EFAULT; | |
44 | } else { | |
45 | *err_ptr = 0; | |
46 | } | |
47 | ||
48 | csum = csum_partial(dst, len, sum); | |
49 | } | |
50 | ||
51 | out: | |
de78a9c4 | 52 | prevent_read_from_user(src, len); |
fdd374b6 AB |
53 | return (__force __wsum)csum; |
54 | } | |
55 | EXPORT_SYMBOL(csum_and_copy_from_user); | |
8c773914 AB |
56 | |
57 | __wsum csum_and_copy_to_user(const void *src, void __user *dst, int len, | |
58 | __wsum sum, int *err_ptr) | |
59 | { | |
60 | unsigned int csum; | |
61 | ||
62 | might_sleep(); | |
de78a9c4 | 63 | allow_write_to_user(dst, len); |
8c773914 AB |
64 | |
65 | *err_ptr = 0; | |
66 | ||
67 | if (!len) { | |
68 | csum = 0; | |
69 | goto out; | |
70 | } | |
71 | ||
96d4f267 | 72 | if (unlikely((len < 0) || !access_ok(dst, len))) { |
8c773914 AB |
73 | *err_ptr = -EFAULT; |
74 | csum = -1; /* invalid checksum */ | |
75 | goto out; | |
76 | } | |
77 | ||
78 | csum = csum_partial_copy_generic(src, (void __force *)dst, | |
79 | len, sum, NULL, err_ptr); | |
80 | ||
81 | if (unlikely(*err_ptr)) { | |
82 | csum = csum_partial(src, len, sum); | |
83 | ||
84 | if (copy_to_user(dst, src, len)) { | |
85 | *err_ptr = -EFAULT; | |
86 | csum = -1; /* invalid checksum */ | |
87 | } | |
88 | } | |
89 | ||
90 | out: | |
de78a9c4 | 91 | prevent_write_to_user(dst, len); |
8c773914 AB |
92 | return (__force __wsum)csum; |
93 | } | |
94 | EXPORT_SYMBOL(csum_and_copy_to_user); |