1 /* 2 * chap-new.c - New CHAP implementation. 3 * 4 * Copyright (c) 2003 Paul Mackerras. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 13 * 2. The name(s) of the authors of this software must not be used to 14 * endorse or promote products derived from this software without 15 * prior written permission. 16 * 17 * 3. Redistributions of any form whatsoever must retain the following 18 * acknowledgment: 19 * "This product includes software developed by Paul Mackerras 20 * <paulus (at) samba.org>". 21 * 22 * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO 23 * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY 24 * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY 25 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 26 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN 27 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING 28 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 29 */ 30 31 /* 32 * CHAP packets begin with a standard header with code, id, len (2 bytes). 33 */ 34 #define CHAP_HDRLEN 4 35 36 /* 37 * Values for the code field. 38 */ 39 #define CHAP_CHALLENGE 1 40 #define CHAP_RESPONSE 2 41 #define CHAP_SUCCESS 3 42 #define CHAP_FAILURE 4 43 44 /* 45 * CHAP digest codes. 46 */ 47 #define CHAP_MD5 5 48 #define CHAP_MICROSOFT 0x80 49 #define CHAP_MICROSOFT_V2 0x81 50 51 /* 52 * Semi-arbitrary limits on challenge and response fields. 53 */ 54 #define MAX_CHALLENGE_LEN 64 55 #define MAX_RESPONSE_LEN 64 56 57 /* bitmask of supported algorithms */ 58 #define MDTYPE_MICROSOFT_V2 0x1 59 #define MDTYPE_MICROSOFT 0x2 60 #define MDTYPE_MD5 0x4 61 #define MDTYPE_NONE 0 62 63 /* hashes supported by this instance of pppd */ 64 extern int chap_mdtype_all; 65 66 /* Return the digest alg. ID for the most preferred digest type. */ 67 #define CHAP_DIGEST(mdtype) \ 68 ((mdtype) & MDTYPE_MD5)? CHAP_MD5: \ 69 ((mdtype) & MDTYPE_MICROSOFT_V2)? CHAP_MICROSOFT_V2: \ 70 ((mdtype) & MDTYPE_MICROSOFT)? CHAP_MICROSOFT: \ 71 0 72 73 /* Return the bit flag (lsb set) for our most preferred digest type. */ 74 #define CHAP_MDTYPE(mdtype) ((mdtype) ^ ((mdtype) - 1)) & (mdtype) 75 76 /* Return the bit flag for a given digest algorithm ID. */ 77 #define CHAP_MDTYPE_D(digest) \ 78 ((digest) == CHAP_MICROSOFT_V2)? MDTYPE_MICROSOFT_V2: \ 79 ((digest) == CHAP_MICROSOFT)? MDTYPE_MICROSOFT: \ 80 ((digest) == CHAP_MD5)? MDTYPE_MD5: \ 81 0 82 83 /* Can we do the requested digest? */ 84 #define CHAP_CANDIGEST(mdtype, digest) \ 85 ((digest) == CHAP_MICROSOFT_V2)? (mdtype) & MDTYPE_MICROSOFT_V2: \ 86 ((digest) == CHAP_MICROSOFT)? (mdtype) & MDTYPE_MICROSOFT: \ 87 ((digest) == CHAP_MD5)? (mdtype) & MDTYPE_MD5: \ 88 0 89 90 /* 91 * The code for each digest type has to supply one of these. 92 */ 93 struct chap_digest_type { 94 int code; 95 96 /* 97 * Note: challenge and response arguments below are formatted as 98 * a length byte followed by the actual challenge/response data. 99 */ 100 void (*generate_challenge)(unsigned char *challenge); 101 int (*verify_response)(int id, char *name, 102 unsigned char *secret, int secret_len, 103 unsigned char *challenge, unsigned char *response, 104 char *message, int message_space); 105 void (*make_response)(unsigned char *response, int id, char *our_name, 106 unsigned char *challenge, char *secret, int secret_len, 107 unsigned char *priv); 108 int (*check_success)(unsigned char *pkt, int len, unsigned char *priv); 109 void (*handle_failure)(unsigned char *pkt, int len); 110 111 struct chap_digest_type *next; 112 }; 113 114 /* Hook for a plugin to validate CHAP challenge */ 115 extern int (*chap_verify_hook)(char *name, char *ourname, int id, 116 struct chap_digest_type *digest, 117 unsigned char *challenge, unsigned char *response, 118 char *message, int message_space); 119 120 /* Called by digest code to register a digest type */ 121 extern void chap_register_digest(struct chap_digest_type *); 122 123 /* Called by authentication code to start authenticating the peer. */ 124 extern void chap_auth_peer(int unit, char *our_name, int digest_code); 125 126 /* Called by auth. code to start authenticating us to the peer. */ 127 extern void chap_auth_with_peer(int unit, char *our_name, int digest_code); 128 129 /* Represents the CHAP protocol to the main pppd code */ 130 extern struct protent chap_protent; 131
