3 * $Id: crypt.h,v 1.1 1997/07/21 13:47:51 mdw Exp $
5 * Cryptographic transfer of `become' requests
10 /*----- Licencing 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
26 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
29 /*----- Revision history --------------------------------------------------*
32 * Revision 1.1 1997/07/21 13:47:51 mdw
44 /*----- Required headers --------------------------------------------------*/
56 /*----- Type definitions and data structures ------------------------------*/
58 /* --- Encryption formats --- */
61 cryptType_idea
, /* Symmetric IDEA encryption */
62 cryptType_rsa
/* Public key RSA (later project) */
65 /* --- Encrypted buffer format --- *
67 * C structures are no good here. Time for some explicit offsets.
71 crq_cryptType
= 0, /* Encryption type (1 byte) */
72 crq_iv
= crq_cryptType
+ 1, /* Plaintext IV (8 bytes) */
73 crq_session
= crq_iv
+ 8, /* IDEA session key (16 bytes) */
74 crq_cipher
= crq_session
+ 16, /* Where to start encrypting */
75 crq_time
= crq_cipher
, /* Time stamp (4 bytes) */
76 crq_pid
= crq_time
+ 4, /* Process ID (4 bytes) */
77 crq_from
= crq_pid
+ 4, /* From user id (4 bytes) */
78 crq_to
= crq_from
+ 4, /* To user id (4 bytes) */
79 crq_cmd
= crq_to
+ 4, /* Command string (lots of bytes) */
80 crq_check
= crq_cmd
+ CMDLEN_MAX
, /* Checksum for request (4 bytes) */
81 crq_size
= crq_check
+ 4 /* Size of encrypted request */
84 /* --- Encrypted result format --- */
87 crp_iv
= 0, /* Plaintext IV (8 bytes) */
88 crp_cipher
= crp_iv
+ 8, /* Where to start encrypting */
89 crp_time
= crp_cipher
, /* Time of request (4 bytes) */
90 crp_pid
= crp_time
+ 4, /* Process ID of client (4 bytes) */
91 crp_answer
= crp_pid
+ 4, /* Answer (1 or 0) (1 byte) */
92 crp_check
= crp_answer
+ 1, /* Checksum for reply (4 bytes) */
93 crp_size
= crp_check
+ 4 /* Size of encrypted reply */
96 /*----- Macros ------------------------------------------------------------*/
100 * Arguments: @obj@ = some object
102 * Use: Writes zero bytes over the object.
105 #define burn(obj) ((void)memset(&obj, 0, sizeof(obj)))
107 /*----- Functions provided ------------------------------------------------*/
109 /* --- @crypt_packRequest@ --- *
111 * Arguments: @request *rq@ = pointer to request block
112 * @unsigned char *buff@ = pointer to a buffer
113 * @time_t t@ = the current time
114 * @pid_t pid@ = my process ID
115 * @unsigned char *k@ = pointer to 128-bit key
116 * @unsigned char *sk@ = where to put the session key
118 * Returns: The number of bytes written.
120 * Use: Packs a request block into a buffer. The buffer should have
121 * space for at least @crq_size@ bytes. The buffer comes back
122 * encrypted and ready to send.
125 extern void crypt_packRequest(request */
*rq*/
, unsigned char */
*buff*/
,
126 time_t /*t*/, pid_t
/*pid*/,
127 unsigned char */
*k*/
, unsigned char */
*sk*/
);
129 /* --- @crypt_unpackRequest@ --- *
131 * Arguments: @reqest *rq@ = pointer to destination request block
132 * @unsigned char *buff@ = pointer to source buffer
133 * @unsigned char *k@ = pointer to encryption key
134 * @unsigned char *sk@ = pointer to where to store session key
135 * @unsigned char *rpl@ = where to start building reply
139 * Use: Decrypts and unpacks a request buffer.
142 extern int crypt_unpackRequest(request */
*rq*/
, unsigned char */
*buff*/
,
143 unsigned char */
*k*/
, unsigned char */
*sk*/
,
144 unsigned char */
*rpl*/
);
146 /* --- @crypt_packReply@ --- *
148 * Arguments: @unsigned char *buff@ = pointer to reply block
149 * @unsigned char *sk@ = pointer to session key
150 * @int answer@ = yes or no
154 * Use: Packs and encrypts a reply block.
157 extern void crypt_packReply(unsigned char */
*buff*/
, unsigned char */
*sk*/
,
160 /* --- @crypt_unpackReply@ --- *
162 * Arguments: @unsigned char *buff@ = pointer to reply buffer
163 * @unsigned char *sk@ = pointer to session key
164 * @time_t t@ = time at which request was sent
165 * @pid_t pid@ = my process ID
167 * Returns: >0 if request granted, zero if denied, <0 if reply rejected
169 * Use: Unpacks a reply block, and informs the caller of the outcome.
172 extern int crypt_unpackReply(unsigned char */
*buff*/
, unsigned char */
*sk*/
,
173 time_t /*t*/, pid_t
/*pid*/);
175 /*----- That's all, folks -------------------------------------------------*/