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1 /*
2  * EAP server/peer: EAP-pwd shared definitions
3  * Copyright (c) 2009, Dan Harkins <dharkins@lounge.org>
4  *
5  * This software may be distributed under the terms of the BSD license.
6  * See README for more details.
7  */
8 
9 #ifndef EAP_PWD_COMMON_H
10 #define EAP_PWD_COMMON_H
11 
12 /*
13  * definition of a finite cyclic group
14  * TODO: support one based on a prime field
15  */
16 typedef struct group_definition_ {
17 	u16 group_num;
18 	struct crypto_ec *group;
19 	struct crypto_ec_point *pwe;
20 } EAP_PWD_group;
21 
22 /*
23  * EAP-pwd header, included on all payloads
24  * L(1 bit) | M(1 bit) | exch(6 bits) | total_length(if L is set)
25  */
26 #define EAP_PWD_HDR_SIZE                1
27 
28 #define EAP_PWD_OPCODE_ID_EXCH          1
29 #define EAP_PWD_OPCODE_COMMIT_EXCH      2
30 #define EAP_PWD_OPCODE_CONFIRM_EXCH     3
31 #define EAP_PWD_GET_LENGTH_BIT(x)       ((x) & 0x80)
32 #define EAP_PWD_SET_LENGTH_BIT(x)       ((x) |= 0x80)
33 #define EAP_PWD_GET_MORE_BIT(x)         ((x) & 0x40)
34 #define EAP_PWD_SET_MORE_BIT(x)         ((x) |= 0x40)
35 #define EAP_PWD_GET_EXCHANGE(x)         ((x) & 0x3f)
36 #define EAP_PWD_SET_EXCHANGE(x,y)       ((x) |= (y))
37 
38 /* EAP-pwd-ID payload */
39 struct eap_pwd_id {
40 	be16 group_num;
41 	u8 random_function;
42 #define EAP_PWD_DEFAULT_RAND_FUNC       1
43 	u8 prf;
44 #define EAP_PWD_DEFAULT_PRF             1
45 	u8 token[4];
46 	u8 prep;
47 #define EAP_PWD_PREP_NONE               0
48 #define EAP_PWD_PREP_MS                 1
49 #define EAP_PWD_PREP_SSHA1              3
50 #define EAP_PWD_PREP_SSHA256            4
51 #define EAP_PWD_PREP_SSHA512            5
52 	u8 identity[0];     /* length inferred from payload */
53 } STRUCT_PACKED;
54 
55 /* common routines */
56 EAP_PWD_group * get_eap_pwd_group(u16 num);
57 int compute_password_element(EAP_PWD_group *grp, u16 num,
58 			     const u8 *password, size_t password_len,
59 			     const u8 *id_server, size_t id_server_len,
60 			     const u8 *id_peer, size_t id_peer_len,
61 			     const u8 *token);
62 int compute_keys(EAP_PWD_group *grp, const struct crypto_bignum *k,
63 		 const struct crypto_bignum *peer_scalar,
64 		 const struct crypto_bignum  *server_scalar,
65 		 const u8 *confirm_peer, const u8 *confirm_server,
66 		 const u32 *ciphersuite, u8 *msk, u8 *emsk, u8 *session_id);
67 struct crypto_hash * eap_pwd_h_init(void);
68 void eap_pwd_h_update(struct crypto_hash *hash, const u8 *data, size_t len);
69 void eap_pwd_h_final(struct crypto_hash *hash, u8 *digest);
70 struct crypto_ec_point * eap_pwd_get_element(EAP_PWD_group *group,
71 					     const u8 *buf);
72 struct crypto_bignum * eap_pwd_get_scalar(EAP_PWD_group *group, const u8 *buf);
73 int eap_pwd_get_rand_mask(EAP_PWD_group *group, struct crypto_bignum *_rand,
74 			  struct crypto_bignum *_mask,
75 			  struct crypto_bignum *scalar);
76 
77 #endif  /* EAP_PWD_COMMON_H */
78