blob: 3cd8a2414e60e6ec9ecd3060a8f5ea4944747cc4
1 | /* |
2 | * Copyright (c) 2016, Intel Corporation |
3 | * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com> |
4 | * |
5 | * This program is free software; you can redistribute it and/or |
6 | * modify it under the terms of the GNU General Public Licence |
7 | * as published by the Free Software Foundation; either version |
8 | * 2 of the Licence, or (at your option) any later version. |
9 | */ |
10 | #include <linux/kernel.h> |
11 | #include <linux/export.h> |
12 | #include <linux/err.h> |
13 | #include <linux/string.h> |
14 | #include <crypto/ecdh.h> |
15 | #include <crypto/kpp.h> |
16 | |
17 | #define ECDH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + 2 * sizeof(short)) |
18 | |
19 | static inline u8 *ecdh_pack_data(void *dst, const void *src, size_t sz) |
20 | { |
21 | memcpy(dst, src, sz); |
22 | return dst + sz; |
23 | } |
24 | |
25 | static inline const u8 *ecdh_unpack_data(void *dst, const void *src, size_t sz) |
26 | { |
27 | memcpy(dst, src, sz); |
28 | return src + sz; |
29 | } |
30 | |
31 | int crypto_ecdh_key_len(const struct ecdh *params) |
32 | { |
33 | return ECDH_KPP_SECRET_MIN_SIZE + params->key_size; |
34 | } |
35 | EXPORT_SYMBOL_GPL(crypto_ecdh_key_len); |
36 | |
37 | int crypto_ecdh_encode_key(char *buf, unsigned int len, |
38 | const struct ecdh *params) |
39 | { |
40 | u8 *ptr = buf; |
41 | struct kpp_secret secret = { |
42 | .type = CRYPTO_KPP_SECRET_TYPE_ECDH, |
43 | .len = len |
44 | }; |
45 | |
46 | if (unlikely(!buf)) |
47 | return -EINVAL; |
48 | |
49 | if (len != crypto_ecdh_key_len(params)) |
50 | return -EINVAL; |
51 | |
52 | ptr = ecdh_pack_data(ptr, &secret, sizeof(secret)); |
53 | ptr = ecdh_pack_data(ptr, ¶ms->curve_id, sizeof(params->curve_id)); |
54 | ptr = ecdh_pack_data(ptr, ¶ms->key_size, sizeof(params->key_size)); |
55 | ecdh_pack_data(ptr, params->key, params->key_size); |
56 | |
57 | return 0; |
58 | } |
59 | EXPORT_SYMBOL_GPL(crypto_ecdh_encode_key); |
60 | |
61 | int crypto_ecdh_decode_key(const char *buf, unsigned int len, |
62 | struct ecdh *params) |
63 | { |
64 | const u8 *ptr = buf; |
65 | struct kpp_secret secret; |
66 | |
67 | if (unlikely(!buf || len < ECDH_KPP_SECRET_MIN_SIZE)) |
68 | return -EINVAL; |
69 | |
70 | ptr = ecdh_unpack_data(&secret, ptr, sizeof(secret)); |
71 | if (secret.type != CRYPTO_KPP_SECRET_TYPE_ECDH) |
72 | return -EINVAL; |
73 | |
74 | ptr = ecdh_unpack_data(¶ms->curve_id, ptr, sizeof(params->curve_id)); |
75 | ptr = ecdh_unpack_data(¶ms->key_size, ptr, sizeof(params->key_size)); |
76 | if (secret.len != crypto_ecdh_key_len(params)) |
77 | return -EINVAL; |
78 | |
79 | /* Don't allocate memory. Set pointer to data |
80 | * within the given buffer |
81 | */ |
82 | params->key = (void *)ptr; |
83 | |
84 | return 0; |
85 | } |
86 | EXPORT_SYMBOL_GPL(crypto_ecdh_decode_key); |
87 |