3 * $Id: crypt.h,v 1.4 1998/01/12 16:45:57 mdw Exp $
5 * Cryptographic transfer of `become' requests
10 /*----- Licensing notice --------------------------------------------------*
12 * This file is part of `become'
14 * `Become' is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
19 * `Become' is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with `become'; if not, write to the Free Software Foundation,
26 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
29 /*----- Revision history --------------------------------------------------*
32 * Revision 1.4 1998/01/12 16:45:57 mdw
35 * Revision 1.3 1997/09/26 09:14:58 mdw
36 * Merged blowfish branch into trunk.
38 * Revision 1.2.2.1 1997/09/26 09:08:04 mdw
39 * Use the Blowfish encryption algorithm instead of IDEA. This is partly
40 * because I prefer Blowfish (without any particularly strong evidence) but
41 * mainly because IDEA is patented and Blowfish isn't.
43 * Revision 1.2 1997/08/04 10:24:21 mdw
44 * Sources placed under CVS control.
46 * Revision 1.1 1997/07/21 13:47:51 mdw
58 /*----- Required headers --------------------------------------------------*/
70 /*----- Type definitions and data structures ------------------------------*/
72 /* --- Encryption formats --- */
75 cryptType_blowfish, /* Symmetric Blowfish encryption */
76 cryptType_rsa /* Public key RSA (later project) */
79 /* --- Blowfish has a variable key size --- *
81 * Fix a key size here.
84 #define BLOWFISH_KEYSIZE (16u)
86 /* --- Encrypted buffer format --- *
88 * C structures are no good here. Time for some explicit offsets.
92 crq_cryptType = 0, /* Encryption type (1 byte) */
93 crq_iv = crq_cryptType + 1, /* Plaintext IV (8 bytes) */
94 crq_session = crq_iv + 8, /* Session key (16 bytes) */
95 crq_cipher = crq_session + 16, /* Where to start encrypting */
96 crq_time = crq_cipher, /* Time stamp (4 bytes) */
97 crq_pid = crq_time + 4, /* Process ID (4 bytes) */
98 crq_from = crq_pid + 4, /* From user id (4 bytes) */
99 crq_to = crq_from + 4, /* To user id (4 bytes) */
100 crq_cmd = crq_to + 4, /* Command string (lots of bytes) */
101 crq_check = crq_cmd + CMDLEN_MAX, /* Checksum for request (4 bytes) */
102 crq_size = crq_check + 4 /* Size of encrypted request */
105 /* --- Encrypted result format --- */
108 crp_iv = 0, /* Plaintext IV (8 bytes) */
109 crp_cipher = crp_iv + 8, /* Where to start encrypting */
110 crp_time = crp_cipher, /* Time of request (4 bytes) */
111 crp_pid = crp_time + 4, /* Process ID of client (4 bytes) */
112 crp_answer = crp_pid + 4, /* Answer (1 or 0) (1 byte) */
113 crp_check = crp_answer + 1, /* Checksum for reply (4 bytes) */
114 crp_size = crp_check + 4 /* Size of encrypted reply */
117 /*----- Functions provided ------------------------------------------------*/
119 /* --- @crypt_packRequest@ --- *
121 * Arguments: @request *rq@ = pointer to request block
122 * @unsigned char *buff@ = pointer to a buffer
123 * @time_t t@ = the current time
124 * @pid_t pid@ = my process ID
125 * @unsigned char *k@ = pointer to 128-bit key
126 * @unsigned char *sk@ = where to put the session key
128 * Returns: The number of bytes written.
130 * Use: Packs a request block into a buffer. The buffer should have
131 * space for at least @crq_size@ bytes. The buffer comes back
132 * encrypted and ready to send.
135 extern void crypt_packRequest(request */*rq*/, unsigned char */*buff*/,
136 time_t /*t*/, pid_t /*pid*/,
137 unsigned char */*k*/, unsigned char */*sk*/);
139 /* --- @crypt_unpackRequest@ --- *
141 * Arguments: @reqest *rq@ = pointer to destination request block
142 * @unsigned char *buff@ = pointer to source buffer
143 * @unsigned char *k@ = pointer to encryption key
144 * @unsigned char *sk@ = pointer to where to store session key
145 * @unsigned char *rpl@ = where to start building reply
149 * Use: Decrypts and unpacks a request buffer.
152 extern int crypt_unpackRequest(request */*rq*/, unsigned char */*buff*/,
153 unsigned char */*k*/, unsigned char */*sk*/,
154 unsigned char */*rpl*/);
156 /* --- @crypt_packReply@ --- *
158 * Arguments: @unsigned char *buff@ = pointer to reply block
159 * @unsigned char *sk@ = pointer to session key
160 * @int answer@ = yes or no
164 * Use: Packs and encrypts a reply block.
167 extern void crypt_packReply(unsigned char */*buff*/, unsigned char */*sk*/,
170 /* --- @crypt_unpackReply@ --- *
172 * Arguments: @unsigned char *buff@ = pointer to reply buffer
173 * @unsigned char *sk@ = pointer to session key
174 * @time_t t@ = time at which request was sent
175 * @pid_t pid@ = my process ID
177 * Returns: >0 if request granted, zero if denied, <0 if reply rejected
179 * Use: Unpacks a reply block, and informs the caller of the outcome.
182 extern int crypt_unpackReply(unsigned char */*buff*/, unsigned char */*sk*/,
183 time_t /*t*/, pid_t /*pid*/);
185 /*----- That's all, folks -------------------------------------------------*/