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      1 /*
      2  * EAP server/peer: EAP-pwd shared definitions
      3  * Copyright (c) 2009, Dan Harkins <dharkins (at) lounge.org>
      4  *
      5  * This program is free software; you can redistribute it and/or modify
      6  * it under the terms of the BSD license.
      7  *
      8  * Alternatively, this software may be distributed under the terms of the
      9  * GNU General Public License version 2 as published by the Free Software
     10  * Foundation.
     11  *
     12  * See README and COPYING for more details.
     13  */
     14 
     15 #ifndef EAP_PWD_COMMON_H
     16 #define EAP_PWD_COMMON_H
     17 
     18 #include <openssl/bn.h>
     19 #include <openssl/sha.h>
     20 #include <openssl/ec.h>
     21 #include <openssl/evp.h>
     22 #include <openssl/hmac.h>
     23 
     24 /*
     25  * definition of a finite cyclic group
     26  * TODO: support one based on a prime field
     27  */
     28 typedef struct group_definition_ {
     29 	u16 group_num;
     30 	EC_GROUP *group;
     31 	EC_POINT *pwe;
     32 	BIGNUM *order;
     33 	BIGNUM *prime;
     34 } EAP_PWD_group;
     35 
     36 /*
     37  * EAP-pwd header, included on all payloads
     38  */
     39 struct eap_pwd_hdr {
     40 	u8 l_bit:1;
     41 	u8 m_bit:1;
     42 	u8 exch:6;
     43 	u8 total_length[0];         /* included when l_bit is set */
     44 } STRUCT_PACKED;
     45 
     46 #define EAP_PWD_OPCODE_ID_EXCH          1
     47 #define EAP_PWD_OPCODE_COMMIT_EXCH      2
     48 #define EAP_PWD_OPCODE_CONFIRM_EXCH     3
     49 #define EAP_PWD_GET_LENGTH_BIT(x)       ((x)->lm_exch & 0x80)
     50 #define EAP_PWD_SET_LENGTH_BIT(x)       ((x)->lm_exch |= 0x80)
     51 #define EAP_PWD_GET_MORE_BIT(x)         ((x)->lm_exch & 0x40)
     52 #define EAP_PWD_SET_MORE_BIT(x)         ((x)->lm_exch |= 0x40)
     53 #define EAP_PWD_GET_EXCHANGE(x)         ((x)->lm_exch & 0x3f)
     54 #define EAP_PWD_SET_EXCHANGE(x,y)       ((x)->lm_exch |= (y))
     55 
     56 /* EAP-pwd-ID payload */
     57 struct eap_pwd_id {
     58 	be16 group_num;
     59 	u8 random_function;
     60 #define EAP_PWD_DEFAULT_RAND_FUNC       1
     61 	u8 prf;
     62 #define EAP_PWD_DEFAULT_PRF             1
     63 	u8 token[4];
     64 	u8 prep;
     65 #define EAP_PWD_PREP_NONE               0
     66 #define EAP_PWD_PREP_MS                 1
     67 	u8 identity[0];     /* length inferred from payload */
     68 } STRUCT_PACKED;
     69 
     70 /* common routines */
     71 int compute_password_element(EAP_PWD_group *, u16, u8 *, int, u8 *, int, u8 *,
     72 			     int, u8 *);
     73 int compute_keys(EAP_PWD_group *, BN_CTX *, BIGNUM *, BIGNUM *, BIGNUM *,
     74 		 u8 *, u8 *, u32 *, u8 *, u8 *);
     75 void H_Init(HMAC_CTX *);
     76 void H_Update(HMAC_CTX *, const u8 *, int);
     77 void H_Final(HMAC_CTX *, u8 *);
     78 
     79 #endif  /* EAP_PWD_COMMON_H */
     80