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chap-new.h
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@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#include "ppp_opts.h"
32#if PPP_SUPPORT && CHAP_SUPPORT /* don't build if not configured for use in ppp_opts.h */
33
34#ifndef CHAP_H
35#define CHAP_H
36
37#include "ppp.h"
38
39#ifdef __cplusplus
40extern "C" {
41#endif
42
43/*
44 * CHAP packets begin with a standard header with code, id, len (2 bytes).
45 */
46#define CHAP_HDRLEN 4
47
48/*
49 * Values for the code field.
50 */
51#define CHAP_CHALLENGE 1
52#define CHAP_RESPONSE 2
53#define CHAP_SUCCESS 3
54#define CHAP_FAILURE 4
55
56/*
57 * CHAP digest codes.
58 */
59#define CHAP_MD5 5
60#if MSCHAP_SUPPORT
61#define CHAP_MICROSOFT 0x80
62#define CHAP_MICROSOFT_V2 0x81
63#endif /* MSCHAP_SUPPORT */
64
65/*
66 * Semi-arbitrary limits on challenge and response fields.
67 */
68#define MAX_CHALLENGE_LEN 64
69#define MAX_RESPONSE_LEN 64
70
71/*
72 * These limits apply to challenge and response packets we send.
73 * The +4 is the +1 that we actually need rounded up.
74 */
75#define CHAL_MAX_PKTLEN (PPP_HDRLEN + CHAP_HDRLEN + 4 + MAX_CHALLENGE_LEN + MAXNAMELEN)
76#define RESP_MAX_PKTLEN (PPP_HDRLEN + CHAP_HDRLEN + 4 + MAX_RESPONSE_LEN + MAXNAMELEN)
77
78/* bitmask of supported algorithms */
79#if MSCHAP_SUPPORT
80#define MDTYPE_MICROSOFT_V2 0x1
81#define MDTYPE_MICROSOFT 0x2
82#endif /* MSCHAP_SUPPORT */
83#define MDTYPE_MD5 0x4
84#define MDTYPE_NONE 0
85
86#if MSCHAP_SUPPORT
87/* Return the digest alg. ID for the most preferred digest type. */
88#define CHAP_DIGEST(mdtype) \
89 ((mdtype) & MDTYPE_MD5)? CHAP_MD5: \
90 ((mdtype) & MDTYPE_MICROSOFT_V2)? CHAP_MICROSOFT_V2: \
91 ((mdtype) & MDTYPE_MICROSOFT)? CHAP_MICROSOFT: \
92 0
93#else /* !MSCHAP_SUPPORT */
94#define CHAP_DIGEST(mdtype) \
95 ((mdtype) & MDTYPE_MD5)? CHAP_MD5: \
96 0
97#endif /* MSCHAP_SUPPORT */
98
99/* Return the bit flag (lsb set) for our most preferred digest type. */
100#define CHAP_MDTYPE(mdtype) ((mdtype) ^ ((mdtype) - 1)) & (mdtype)
101
102/* Return the bit flag for a given digest algorithm ID. */
103#if MSCHAP_SUPPORT
104#define CHAP_MDTYPE_D(digest) \
105 ((digest) == CHAP_MICROSOFT_V2)? MDTYPE_MICROSOFT_V2: \
106 ((digest) == CHAP_MICROSOFT)? MDTYPE_MICROSOFT: \
107 ((digest) == CHAP_MD5)? MDTYPE_MD5: \
108 0
109#else /* !MSCHAP_SUPPORT */
110#define CHAP_MDTYPE_D(digest) \
111 ((digest) == CHAP_MD5)? MDTYPE_MD5: \
112 0
113#endif /* MSCHAP_SUPPORT */
114
115/* Can we do the requested digest? */
116#if MSCHAP_SUPPORT
117#define CHAP_CANDIGEST(mdtype, digest) \
118 ((digest) == CHAP_MICROSOFT_V2)? (mdtype) & MDTYPE_MICROSOFT_V2: \
119 ((digest) == CHAP_MICROSOFT)? (mdtype) & MDTYPE_MICROSOFT: \
120 ((digest) == CHAP_MD5)? (mdtype) & MDTYPE_MD5: \
121 0
122#else /* !MSCHAP_SUPPORT */
123#define CHAP_CANDIGEST(mdtype, digest) \
124 ((digest) == CHAP_MD5)? (mdtype) & MDTYPE_MD5: \
125 0
126#endif /* MSCHAP_SUPPORT */
127
128/*
129 * The code for each digest type has to supply one of these.
130 */
131struct chap_digest_type {
132 int code;
133
134#if PPP_SERVER
135 /*
136 * Note: challenge and response arguments below are formatted as
137 * a length byte followed by the actual challenge/response data.
138 */
139 void (*generate_challenge)(ppp_pcb *pcb, unsigned char *challenge);
140 int (*verify_response)(ppp_pcb *pcb, int id, const char *name,
141 const unsigned char *secret, int secret_len,
142 const unsigned char *challenge, const unsigned char *response,
143 char *message, int message_space);
144#endif /* PPP_SERVER */
145 void (*make_response)(ppp_pcb *pcb, unsigned char *response, int id, const char *our_name,
146 const unsigned char *challenge, const char *secret, int secret_len,
147 unsigned char *priv);
148 int (*check_success)(ppp_pcb *pcb, unsigned char *pkt, int len, unsigned char *priv);
149 void (*handle_failure)(ppp_pcb *pcb, unsigned char *pkt, int len);
150};
151
152/*
153 * Each interface is described by chap structure.
154 */
155#if CHAP_SUPPORT
156typedef struct chap_client_state {
157 u8_t flags;
158 const char *name;
159 const struct chap_digest_type *digest;
160 unsigned char priv[64]; /* private area for digest's use */
161} chap_client_state;
162
163#if PPP_SERVER
164typedef struct chap_server_state {
165 u8_t flags;
166 u8_t id;
167 const char *name;
168 const struct chap_digest_type *digest;
169 int challenge_xmits;
170 int challenge_pktlen;
171 unsigned char challenge[CHAL_MAX_PKTLEN];
172} chap_server_state;
173#endif /* PPP_SERVER */
174#endif /* CHAP_SUPPORT */
175
176#if 0 /* UNUSED */
177/* Hook for a plugin to validate CHAP challenge */
178extern int (*chap_verify_hook)(char *name, char *ourname, int id,
179 const struct chap_digest_type *digest,
180 unsigned char *challenge, unsigned char *response,
181 char *message, int message_space);
182#endif /* UNUSED */
183
184#if PPP_SERVER
185/* Called by authentication code to start authenticating the peer. */
186extern void chap_auth_peer(ppp_pcb *pcb, const char *our_name, int digest_code);
187#endif /* PPP_SERVER */
188
189/* Called by auth. code to start authenticating us to the peer. */
190extern void chap_auth_with_peer(ppp_pcb *pcb, const char *our_name, int digest_code);
191
192/* Represents the CHAP protocol to the main pppd code */
193extern const struct protent chap_protent;
194
195#ifdef __cplusplus
196}
197#endif
198
199#endif /* CHAP_H */
200#endif /* PPP_SUPPORT && CHAP_SUPPORT */