1 | /* |
2 | * Off-the-Record Messaging library |
3 | * Copyright (C) 2004-2012 Ian Goldberg, Rob Smits, Chris Alexander, |
4 | * Willy Lew, Lisa Du, Nikita Borisov |
5 | * <otr@cypherpunks.ca> |
6 | * |
7 | * This library is free software; you can redistribute it and/or |
8 | * modify it under the terms of version 2.1 of the GNU Lesser General |
9 | * Public License as published by the Free Software Foundation. |
10 | * |
11 | * This library is distributed in the hope that it will be useful, |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
14 | * Lesser General Public License for more details. |
15 | * |
16 | * You should have received a copy of the GNU Lesser General Public |
17 | * License along with this library; if not, write to the Free Software |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
19 | */ |
20 | |
21 | #ifndef __AUTH_H__ |
22 | #define __AUTH_H__ |
23 | |
24 | #include <gcrypt.h> |
25 | #include <time.h> |
26 | #include "dh.h" |
27 | |
28 | |
29 | typedef enum { |
30 | OTRL_AUTHSTATE_NONE, |
31 | OTRL_AUTHSTATE_AWAITING_DHKEY, |
32 | OTRL_AUTHSTATE_AWAITING_REVEALSIG, |
33 | OTRL_AUTHSTATE_AWAITING_SIG, |
34 | OTRL_AUTHSTATE_V1_SETUP |
35 | } OtrlAuthState; |
36 | |
37 | typedef struct { |
38 | OtrlAuthState authstate; /* Our state */ |
39 | |
40 | struct context *context; /* The context which points to us */ |
41 | |
42 | DH_keypair our_dh; /* Our D-H key */ |
43 | unsigned int our_keyid; /* ...and its keyid */ |
44 | |
45 | unsigned char *encgx; /* The encrypted value of g^x */ |
46 | size_t encgx_len; /* ...and its length */ |
47 | unsigned char r[16]; /* The encryption key */ |
48 | |
49 | unsigned char hashgx[32]; /* SHA256(g^x) */ |
50 | |
51 | gcry_mpi_t their_pub; /* Their D-H public key */ |
52 | unsigned int their_keyid; /* ...and its keyid */ |
53 | |
54 | |
55 | gcry_cipher_hd_t enc_c, enc_cp; /* c and c' encryption keys */ |
56 | gcry_md_hd_t mac_m1, mac_m1p; /* m1 and m1' MAC keys */ |
57 | gcry_md_hd_t mac_m2, mac_m2p; /* m2 and m2' MAC keys */ |
58 | |
59 | unsigned char their_fingerprint[20]; /* The fingerprint of their |
60 | long-term signing key */ |
61 | |
62 | int initiated; /* Did we initiate this |
63 | authentication? */ |
64 | |
65 | unsigned int protocol_version; /* The protocol version number |
66 | used to authenticate. */ |
67 | |
68 | unsigned char secure_session_id[20]; /* The secure session id */ |
69 | size_t secure_session_id_len; /* And its actual length, |
70 | which may be either 20 (for |
71 | v1) or 8 (for v2) */ |
72 | OtrlSessionIdHalf session_id_half; /* Which half of the session |
73 | id gets shown in bold */ |
74 | |
75 | char *lastauthmsg; /* The last auth message |
76 | (base-64 encoded) we sent, |
77 | in case we need to |
78 | retransmit it. */ |
79 | |
80 | time_t commit_sent_time; /* The time we last sent the |
81 | lastauthmsg, if it was a |
82 | COMMIT message, and this is |
83 | a master context. 0 |
84 | otherwise. */ |
85 | } OtrlAuthInfo; |
86 | |
87 | #include "privkey-t.h" |
88 | |
89 | /* |
90 | * Initialize the fields of an OtrlAuthInfo (already allocated). |
91 | */ |
92 | void otrl_auth_new(struct context *context); |
93 | |
94 | /* |
95 | * Clear the fields of an OtrlAuthInfo (but leave it allocated). |
96 | */ |
97 | void otrl_auth_clear(OtrlAuthInfo *auth); |
98 | |
99 | /* |
100 | * Start a fresh AKE (version 2 or 3) using the given OtrlAuthInfo. Generate |
101 | * a fresh DH keypair to use. If no error is returned, the message to |
102 | * transmit will be contained in auth->lastauthmsg. |
103 | */ |
104 | gcry_error_t otrl_auth_start_v23(OtrlAuthInfo *auth, int version); |
105 | |
106 | /* |
107 | * Handle an incoming D-H Commit Message. If no error is returned, the |
108 | * message to send will be left in auth->lastauthmsg. Generate a fresh |
109 | * keypair to use. |
110 | */ |
111 | gcry_error_t otrl_auth_handle_commit(OtrlAuthInfo *auth, |
112 | const char *commitmsg, int version); |
113 | |
114 | /* |
115 | * Handle an incoming D-H Key Message. If no error is returned, and |
116 | * *havemsgp is 1, the message to sent will be left in auth->lastauthmsg. |
117 | * Use the given private authentication key to sign messages. |
118 | */ |
119 | gcry_error_t otrl_auth_handle_key(OtrlAuthInfo *auth, const char *keymsg, |
120 | int *havemsgp, OtrlPrivKey *privkey); |
121 | |
122 | /* |
123 | * Handle an incoming Reveal Signature Message. If no error is |
124 | * returned, and *havemsgp is 1, the message to be sent will be left in |
125 | * auth->lastauthmsg. Use the given private authentication key to sign |
126 | * messages. Call the auth_succeeded callback if authentication is |
127 | * successful. |
128 | */ |
129 | gcry_error_t otrl_auth_handle_revealsig(OtrlAuthInfo *auth, |
130 | const char *revealmsg, int *havemsgp, OtrlPrivKey *privkey, |
131 | gcry_error_t (*auth_succeeded)(const OtrlAuthInfo *auth, void *asdata), |
132 | void *asdata); |
133 | |
134 | /* |
135 | * Handle an incoming Signature Message. If no error is returned, and |
136 | * *havemsgp is 1, the message to be sent will be left in |
137 | * auth->lastauthmsg. Call the auth_succeeded callback if |
138 | * authentication is successful. |
139 | */ |
140 | gcry_error_t otrl_auth_handle_signature(OtrlAuthInfo *auth, |
141 | const char *sigmsg, int *havemsgp, |
142 | gcry_error_t (*auth_succeeded)(const OtrlAuthInfo *auth, void *asdata), |
143 | void *asdata); |
144 | |
145 | /* |
146 | * Start a fresh AKE (version 1) using the given OtrlAuthInfo. If |
147 | * our_dh is NULL, generate a fresh DH keypair to use. Otherwise, use a |
148 | * copy of the one passed (with the given keyid). Use the given private |
149 | * key to sign the message. If no error is returned, the message to |
150 | * transmit will be contained in auth->lastauthmsg. |
151 | */ |
152 | gcry_error_t otrl_auth_start_v1(OtrlAuthInfo *auth, DH_keypair *our_dh, |
153 | unsigned int our_keyid, OtrlPrivKey *privkey); |
154 | |
155 | /* |
156 | * Handle an incoming v1 Key Exchange Message. If no error is returned, |
157 | * and *havemsgp is 1, the message to be sent will be left in |
158 | * auth->lastauthmsg. Use the given private authentication key to sign |
159 | * messages. Call the auth_secceeded callback if authentication is |
160 | * successful. If non-NULL, use a copy of the given D-H keypair, with |
161 | * the given keyid. |
162 | */ |
163 | gcry_error_t otrl_auth_handle_v1_key_exchange(OtrlAuthInfo *auth, |
164 | const char *keyexchmsg, int *havemsgp, OtrlPrivKey *privkey, |
165 | DH_keypair *our_dh, unsigned int our_keyid, |
166 | gcry_error_t (*auth_succeeded)(const OtrlAuthInfo *auth, void *asdata), |
167 | void *asdata); |
168 | |
169 | /* |
170 | * Copy relevant information from the master OtrlAuthInfo to an |
171 | * instance OtrlAuthInfo in response to a D-H Key with a new |
172 | * instance. The fields copied will depend on the state of the |
173 | * master auth. |
174 | */ |
175 | void otrl_auth_copy_on_key(OtrlAuthInfo *m_auth, OtrlAuthInfo *auth); |
176 | |
177 | #endif |
178 | |