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 #include <openssl/bn.h>
13 #include <openssl/ec.h>
14 #include <openssl/evp.h>
15 
16 /*
17  * definition of a finite cyclic group
18  * TODO: support one based on a prime field
19  */
20 typedef struct group_definition_ {
21 	u16 group_num;
22 	EC_GROUP *group;
23 	EC_POINT *pwe;
24 	BIGNUM *order;
25 	BIGNUM *prime;
26 } EAP_PWD_group;
27 
28 /*
29  * EAP-pwd header, included on all payloads
30  * L(1 bit) | M(1 bit) | exch(6 bits) | total_length(if L is set)
31  */
32 #define EAP_PWD_HDR_SIZE                1
33 
34 #define EAP_PWD_OPCODE_ID_EXCH          1
35 #define EAP_PWD_OPCODE_COMMIT_EXCH      2
36 #define EAP_PWD_OPCODE_CONFIRM_EXCH     3
37 #define EAP_PWD_GET_LENGTH_BIT(x)       ((x) & 0x80)
38 #define EAP_PWD_SET_LENGTH_BIT(x)       ((x) |= 0x80)
39 #define EAP_PWD_GET_MORE_BIT(x)         ((x) & 0x40)
40 #define EAP_PWD_SET_MORE_BIT(x)         ((x) |= 0x40)
41 #define EAP_PWD_GET_EXCHANGE(x)         ((x) & 0x3f)
42 #define EAP_PWD_SET_EXCHANGE(x,y)       ((x) |= (y))
43 
44 /* EAP-pwd-ID payload */
45 struct eap_pwd_id {
46 	be16 group_num;
47 	u8 random_function;
48 #define EAP_PWD_DEFAULT_RAND_FUNC       1
49 	u8 prf;
50 #define EAP_PWD_DEFAULT_PRF             1
51 	u8 token[4];
52 	u8 prep;
53 #define EAP_PWD_PREP_NONE               0
54 #define EAP_PWD_PREP_MS                 1
55 	u8 identity[0];     /* length inferred from payload */
56 } STRUCT_PACKED;
57 
58 /* common routines */
59 int compute_password_element(EAP_PWD_group *grp, u16 num,
60 			     const u8 *password, size_t password_len,
61 			     const u8 *id_server, size_t id_server_len,
62 			     const u8 *id_peer, size_t id_peer_len,
63 			     const u8 *token);
64 int compute_keys(EAP_PWD_group *grp, BN_CTX *bnctx, const BIGNUM *k,
65 		 const BIGNUM *peer_scalar, const BIGNUM *server_scalar,
66 		 const u8 *confirm_peer, const u8 *confirm_server,
67 		 const u32 *ciphersuite, u8 *msk, u8 *emsk, u8 *session_id);
68 struct crypto_hash * eap_pwd_h_init(void);
69 void eap_pwd_h_update(struct crypto_hash *hash, const u8 *data, size_t len);
70 void eap_pwd_h_final(struct crypto_hash *hash, u8 *digest);
71 
72 #endif  /* EAP_PWD_COMMON_H */
73