1 /* SPDX-License-Identifier: GPL-2.0-or-later * 1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* 2 /*
3 * Diffie-Hellman secret to be used with kpp A 3 * Diffie-Hellman secret to be used with kpp API along with helper functions
4 * 4 *
5 * Copyright (c) 2016, Intel Corporation 5 * Copyright (c) 2016, Intel Corporation
6 * Authors: Salvatore Benedetto <salvatore.ben 6 * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>
7 */ 7 */
8 #ifndef _CRYPTO_DH_ 8 #ifndef _CRYPTO_DH_
9 #define _CRYPTO_DH_ 9 #define _CRYPTO_DH_
10 10
11 /** 11 /**
12 * DOC: DH Helper Functions 12 * DOC: DH Helper Functions
13 * 13 *
14 * To use DH with the KPP cipher API, the foll 14 * To use DH with the KPP cipher API, the following data structure and
15 * functions should be used. 15 * functions should be used.
16 * 16 *
17 * To use DH with KPP, the following functions 17 * To use DH with KPP, the following functions should be used to operate on
18 * a DH private key. The packet private key th 18 * a DH private key. The packet private key that can be set with
19 * the KPP API function call of crypto_kpp_set 19 * the KPP API function call of crypto_kpp_set_secret.
20 */ 20 */
21 21
22 /** 22 /**
23 * struct dh - define a DH private key 23 * struct dh - define a DH private key
24 * 24 *
25 * @key: Private DH key 25 * @key: Private DH key
26 * @p: Diffie-Hellman parameter P 26 * @p: Diffie-Hellman parameter P
>> 27 * @q: Diffie-Hellman parameter Q
27 * @g: Diffie-Hellman generator G 28 * @g: Diffie-Hellman generator G
28 * @key_size: Size of the private DH key 29 * @key_size: Size of the private DH key
29 * @p_size: Size of DH parameter P 30 * @p_size: Size of DH parameter P
>> 31 * @q_size: Size of DH parameter Q
30 * @g_size: Size of DH generator G 32 * @g_size: Size of DH generator G
31 */ 33 */
32 struct dh { 34 struct dh {
33 const void *key; !! 35 void *key;
34 const void *p; !! 36 void *p;
35 const void *g; !! 37 void *q;
>> 38 void *g;
36 unsigned int key_size; 39 unsigned int key_size;
37 unsigned int p_size; 40 unsigned int p_size;
>> 41 unsigned int q_size;
38 unsigned int g_size; 42 unsigned int g_size;
39 }; 43 };
40 44
41 /** 45 /**
42 * crypto_dh_key_len() - Obtain the size of th 46 * crypto_dh_key_len() - Obtain the size of the private DH key
43 * @params: private DH key 47 * @params: private DH key
44 * 48 *
45 * This function returns the packet DH key siz 49 * This function returns the packet DH key size. A caller can use that
46 * with the provided DH private key reference 50 * with the provided DH private key reference to obtain the required
47 * memory size to hold a packet key. 51 * memory size to hold a packet key.
48 * 52 *
49 * Return: size of the key in bytes 53 * Return: size of the key in bytes
50 */ 54 */
51 unsigned int crypto_dh_key_len(const struct dh 55 unsigned int crypto_dh_key_len(const struct dh *params);
52 56
53 /** 57 /**
54 * crypto_dh_encode_key() - encode the private 58 * crypto_dh_encode_key() - encode the private key
55 * @buf: Buffer allocated by the caller 59 * @buf: Buffer allocated by the caller to hold the packet DH
56 * private key. The buffer should 60 * private key. The buffer should be at least crypto_dh_key_len
57 * bytes in size. 61 * bytes in size.
58 * @len: Length of the packet private k 62 * @len: Length of the packet private key buffer
59 * @params: Buffer with the caller-specifi 63 * @params: Buffer with the caller-specified private key
60 * 64 *
61 * The DH implementations operate on a packet 65 * The DH implementations operate on a packet representation of the private
62 * key. 66 * key.
63 * 67 *
64 * Return: -EINVAL if buffer has insuffic 68 * Return: -EINVAL if buffer has insufficient size, 0 on success
65 */ 69 */
66 int crypto_dh_encode_key(char *buf, unsigned i 70 int crypto_dh_encode_key(char *buf, unsigned int len, const struct dh *params);
67 71
68 /** 72 /**
69 * crypto_dh_decode_key() - decode a private k 73 * crypto_dh_decode_key() - decode a private key
70 * @buf: Buffer holding a packet key th 74 * @buf: Buffer holding a packet key that should be decoded
71 * @len: Length of the packet private k 75 * @len: Length of the packet private key buffer
72 * @params: Buffer allocated by the caller 76 * @params: Buffer allocated by the caller that is filled with the
73 * unpacked DH private key. 77 * unpacked DH private key.
74 * 78 *
75 * The unpacking obtains the private key by po 79 * The unpacking obtains the private key by pointing @p to the correct location
76 * in @buf. Thus, both pointers refer to the s 80 * in @buf. Thus, both pointers refer to the same memory.
77 * 81 *
78 * Return: -EINVAL if buffer has insuffic 82 * Return: -EINVAL if buffer has insufficient size, 0 on success
79 */ 83 */
80 int crypto_dh_decode_key(const char *buf, unsi 84 int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params);
81 <<
82 /** <<
83 * __crypto_dh_decode_key() - decode a private <<
84 * @buf: Buffer holding a packet key th <<
85 * @len: Length of the packet private k <<
86 * @params: Buffer allocated by the caller <<
87 * unpacked DH private key. <<
88 * <<
89 * Internal function providing the same servic <<
90 * crypto_dh_decode_key(), but without any of <<
91 * checks conducted by the latter. <<
92 * <<
93 * Return: -EINVAL if buffer has insuffic <<
94 */ <<
95 int __crypto_dh_decode_key(const char *buf, un <<
96 struct dh *params); <<
97 85
98 #endif 86 #endif
99 87
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