crypto/ecdh_helper.c at v5.3 · tjh.dev/kernel

tjh.dev / kernel
Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
kernel / crypto / ecdh_helper.c
at v5.3 2.1 kB view raw
 1// SPDX-License-Identifier: GPL-2.0-or-later
 2/*
 3 * Copyright (c) 2016, Intel Corporation
 4 * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>
 5 */
 6#include <linux/kernel.h>
 7#include <linux/export.h>
 8#include <linux/err.h>
 9#include <linux/string.h>
10#include <crypto/ecdh.h>
11#include <crypto/kpp.h>
12
13#define ECDH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + 2 * sizeof(short))
14
15static inline u8 *ecdh_pack_data(void *dst, const void *src, size_t sz)
16{
17	memcpy(dst, src, sz);
18	return dst + sz;
19}
20
21static inline const u8 *ecdh_unpack_data(void *dst, const void *src, size_t sz)
22{
23	memcpy(dst, src, sz);
24	return src + sz;
25}
26
27unsigned int crypto_ecdh_key_len(const struct ecdh *params)
28{
29	return ECDH_KPP_SECRET_MIN_SIZE + params->key_size;
30}
31EXPORT_SYMBOL_GPL(crypto_ecdh_key_len);
32
33int crypto_ecdh_encode_key(char *buf, unsigned int len,
34			   const struct ecdh *params)
35{
36	u8 *ptr = buf;
37	struct kpp_secret secret = {
38		.type = CRYPTO_KPP_SECRET_TYPE_ECDH,
39		.len = len
40	};
41
42	if (unlikely(!buf))
43		return -EINVAL;
44
45	if (len != crypto_ecdh_key_len(params))
46		return -EINVAL;
47
48	ptr = ecdh_pack_data(ptr, &secret, sizeof(secret));
49	ptr = ecdh_pack_data(ptr, &params->curve_id, sizeof(params->curve_id));
50	ptr = ecdh_pack_data(ptr, &params->key_size, sizeof(params->key_size));
51	ecdh_pack_data(ptr, params->key, params->key_size);
52
53	return 0;
54}
55EXPORT_SYMBOL_GPL(crypto_ecdh_encode_key);
56
57int crypto_ecdh_decode_key(const char *buf, unsigned int len,
58			   struct ecdh *params)
59{
60	const u8 *ptr = buf;
61	struct kpp_secret secret;
62
63	if (unlikely(!buf || len < ECDH_KPP_SECRET_MIN_SIZE))
64		return -EINVAL;
65
66	ptr = ecdh_unpack_data(&secret, ptr, sizeof(secret));
67	if (secret.type != CRYPTO_KPP_SECRET_TYPE_ECDH)
68		return -EINVAL;
69
70	ptr = ecdh_unpack_data(&params->curve_id, ptr, sizeof(params->curve_id));
71	ptr = ecdh_unpack_data(&params->key_size, ptr, sizeof(params->key_size));
72	if (secret.len != crypto_ecdh_key_len(params))
73		return -EINVAL;
74
75	/* Don't allocate memory. Set pointer to data
76	 * within the given buffer
77	 */
78	params->key = (void *)ptr;
79
80	return 0;
81}
82EXPORT_SYMBOL_GPL(crypto_ecdh_decode_key);