1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-or-later
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright (c) 2016, Intel Corporation
4*4882a593Smuzhiyun * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>
5*4882a593Smuzhiyun */
6*4882a593Smuzhiyun #include <linux/kernel.h>
7*4882a593Smuzhiyun #include <linux/export.h>
8*4882a593Smuzhiyun #include <linux/err.h>
9*4882a593Smuzhiyun #include <linux/string.h>
10*4882a593Smuzhiyun #include <crypto/ecdh.h>
11*4882a593Smuzhiyun #include <crypto/kpp.h>
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun #define ECDH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + 2 * sizeof(short))
14*4882a593Smuzhiyun
ecdh_pack_data(void * dst,const void * src,size_t sz)15*4882a593Smuzhiyun static inline u8 *ecdh_pack_data(void *dst, const void *src, size_t sz)
16*4882a593Smuzhiyun {
17*4882a593Smuzhiyun memcpy(dst, src, sz);
18*4882a593Smuzhiyun return dst + sz;
19*4882a593Smuzhiyun }
20*4882a593Smuzhiyun
ecdh_unpack_data(void * dst,const void * src,size_t sz)21*4882a593Smuzhiyun static inline const u8 *ecdh_unpack_data(void *dst, const void *src, size_t sz)
22*4882a593Smuzhiyun {
23*4882a593Smuzhiyun memcpy(dst, src, sz);
24*4882a593Smuzhiyun return src + sz;
25*4882a593Smuzhiyun }
26*4882a593Smuzhiyun
crypto_ecdh_key_len(const struct ecdh * params)27*4882a593Smuzhiyun unsigned int crypto_ecdh_key_len(const struct ecdh *params)
28*4882a593Smuzhiyun {
29*4882a593Smuzhiyun return ECDH_KPP_SECRET_MIN_SIZE + params->key_size;
30*4882a593Smuzhiyun }
31*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(crypto_ecdh_key_len);
32*4882a593Smuzhiyun
crypto_ecdh_encode_key(char * buf,unsigned int len,const struct ecdh * params)33*4882a593Smuzhiyun int crypto_ecdh_encode_key(char *buf, unsigned int len,
34*4882a593Smuzhiyun const struct ecdh *params)
35*4882a593Smuzhiyun {
36*4882a593Smuzhiyun u8 *ptr = buf;
37*4882a593Smuzhiyun struct kpp_secret secret = {
38*4882a593Smuzhiyun .type = CRYPTO_KPP_SECRET_TYPE_ECDH,
39*4882a593Smuzhiyun .len = len
40*4882a593Smuzhiyun };
41*4882a593Smuzhiyun
42*4882a593Smuzhiyun if (unlikely(!buf))
43*4882a593Smuzhiyun return -EINVAL;
44*4882a593Smuzhiyun
45*4882a593Smuzhiyun if (len != crypto_ecdh_key_len(params))
46*4882a593Smuzhiyun return -EINVAL;
47*4882a593Smuzhiyun
48*4882a593Smuzhiyun ptr = ecdh_pack_data(ptr, &secret, sizeof(secret));
49*4882a593Smuzhiyun ptr = ecdh_pack_data(ptr, ¶ms->curve_id, sizeof(params->curve_id));
50*4882a593Smuzhiyun ptr = ecdh_pack_data(ptr, ¶ms->key_size, sizeof(params->key_size));
51*4882a593Smuzhiyun ecdh_pack_data(ptr, params->key, params->key_size);
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun return 0;
54*4882a593Smuzhiyun }
55*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(crypto_ecdh_encode_key);
56*4882a593Smuzhiyun
crypto_ecdh_decode_key(const char * buf,unsigned int len,struct ecdh * params)57*4882a593Smuzhiyun int crypto_ecdh_decode_key(const char *buf, unsigned int len,
58*4882a593Smuzhiyun struct ecdh *params)
59*4882a593Smuzhiyun {
60*4882a593Smuzhiyun const u8 *ptr = buf;
61*4882a593Smuzhiyun struct kpp_secret secret;
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun if (unlikely(!buf || len < ECDH_KPP_SECRET_MIN_SIZE))
64*4882a593Smuzhiyun return -EINVAL;
65*4882a593Smuzhiyun
66*4882a593Smuzhiyun ptr = ecdh_unpack_data(&secret, ptr, sizeof(secret));
67*4882a593Smuzhiyun if (secret.type != CRYPTO_KPP_SECRET_TYPE_ECDH)
68*4882a593Smuzhiyun return -EINVAL;
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun if (unlikely(len < secret.len))
71*4882a593Smuzhiyun return -EINVAL;
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun ptr = ecdh_unpack_data(¶ms->curve_id, ptr, sizeof(params->curve_id));
74*4882a593Smuzhiyun ptr = ecdh_unpack_data(¶ms->key_size, ptr, sizeof(params->key_size));
75*4882a593Smuzhiyun if (secret.len != crypto_ecdh_key_len(params))
76*4882a593Smuzhiyun return -EINVAL;
77*4882a593Smuzhiyun
78*4882a593Smuzhiyun /* Don't allocate memory. Set pointer to data
79*4882a593Smuzhiyun * within the given buffer
80*4882a593Smuzhiyun */
81*4882a593Smuzhiyun params->key = (void *)ptr;
82*4882a593Smuzhiyun
83*4882a593Smuzhiyun return 0;
84*4882a593Smuzhiyun }
85*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(crypto_ecdh_decode_key);
86