chap-new.h

00001 /*
00002  * chap-new.c - New CHAP implementation.
00003  *
00004  * Copyright (c) 2003 Paul Mackerras. All rights reserved.
00005  *
00006  * Redistribution and use in source and binary forms, with or without
00007  * modification, are permitted provided that the following conditions
00008  * are met:
00009  *
00010  * 1. Redistributions of source code must retain the above copyright
00011  *    notice, this list of conditions and the following disclaimer.
00012  *
00013  * 2. The name(s) of the authors of this software must not be used to
00014  *    endorse or promote products derived from this software without
00015  *    prior written permission.
00016  *
00017  * 3. Redistributions of any form whatsoever must retain the following
00018  *    acknowledgment:
00019  *    "This product includes software developed by Paul Mackerras
00020  *     <paulus@samba.org>".
00021  *
00022  * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
00023  * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
00024  * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
00025  * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
00026  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
00027  * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
00028  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
00029  */
00030 
00031 #include "ppp_opts.h"
00032 #if PPP_SUPPORT && CHAP_SUPPORT  /* don't build if not configured for use in ppp_opts.h */
00033 
00034 #ifndef CHAP_H
00035 #define CHAP_H
00036 
00037 #include "ppp.h"
00038 
00039 #ifdef __cplusplus
00040 extern "C" {
00041 #endif
00042 
00043 /*
00044  * CHAP packets begin with a standard header with code, id, len (2 bytes).
00045  */
00046 #define CHAP_HDRLEN 4
00047 
00048 /*
00049  * Values for the code field.
00050  */
00051 #define CHAP_CHALLENGE  1
00052 #define CHAP_RESPONSE   2
00053 #define CHAP_SUCCESS    3
00054 #define CHAP_FAILURE    4
00055 
00056 /*
00057  * CHAP digest codes.
00058  */
00059 #define CHAP_MD5        5
00060 #if MSCHAP_SUPPORT
00061 #define CHAP_MICROSOFT      0x80
00062 #define CHAP_MICROSOFT_V2   0x81
00063 #endif /* MSCHAP_SUPPORT */
00064 
00065 /*
00066  * Semi-arbitrary limits on challenge and response fields.
00067  */
00068 #define MAX_CHALLENGE_LEN   64
00069 #define MAX_RESPONSE_LEN    64
00070 
00071 /*
00072  * These limits apply to challenge and response packets we send.
00073  * The +4 is the +1 that we actually need rounded up.
00074  */
00075 #define CHAL_MAX_PKTLEN (PPP_HDRLEN + CHAP_HDRLEN + 4 + MAX_CHALLENGE_LEN + MAXNAMELEN)
00076 #define RESP_MAX_PKTLEN (PPP_HDRLEN + CHAP_HDRLEN + 4 + MAX_RESPONSE_LEN + MAXNAMELEN)
00077 
00078 /* bitmask of supported algorithms */
00079 #if MSCHAP_SUPPORT
00080 #define MDTYPE_MICROSOFT_V2 0x1
00081 #define MDTYPE_MICROSOFT    0x2
00082 #endif /* MSCHAP_SUPPORT */
00083 #define MDTYPE_MD5      0x4
00084 #define MDTYPE_NONE     0
00085 
00086 #if MSCHAP_SUPPORT
00087 /* Return the digest alg. ID for the most preferred digest type. */
00088 #define CHAP_DIGEST(mdtype) \
00089     ((mdtype) & MDTYPE_MD5)? CHAP_MD5: \
00090     ((mdtype) & MDTYPE_MICROSOFT_V2)? CHAP_MICROSOFT_V2: \
00091     ((mdtype) & MDTYPE_MICROSOFT)? CHAP_MICROSOFT: \
00092     0
00093 #else /* !MSCHAP_SUPPORT */
00094 #define CHAP_DIGEST(mdtype) \
00095     ((mdtype) & MDTYPE_MD5)? CHAP_MD5: \
00096     0
00097 #endif /* MSCHAP_SUPPORT */
00098 
00099 /* Return the bit flag (lsb set) for our most preferred digest type. */
00100 #define CHAP_MDTYPE(mdtype) ((mdtype) ^ ((mdtype) - 1)) & (mdtype)
00101 
00102 /* Return the bit flag for a given digest algorithm ID. */
00103 #if MSCHAP_SUPPORT
00104 #define CHAP_MDTYPE_D(digest) \
00105     ((digest) == CHAP_MICROSOFT_V2)? MDTYPE_MICROSOFT_V2: \
00106     ((digest) == CHAP_MICROSOFT)? MDTYPE_MICROSOFT: \
00107     ((digest) == CHAP_MD5)? MDTYPE_MD5: \
00108     0
00109 #else /* !MSCHAP_SUPPORT */
00110 #define CHAP_MDTYPE_D(digest) \
00111     ((digest) == CHAP_MD5)? MDTYPE_MD5: \
00112     0
00113 #endif /* MSCHAP_SUPPORT */
00114 
00115 /* Can we do the requested digest? */
00116 #if MSCHAP_SUPPORT
00117 #define CHAP_CANDIGEST(mdtype, digest) \
00118     ((digest) == CHAP_MICROSOFT_V2)? (mdtype) & MDTYPE_MICROSOFT_V2: \
00119     ((digest) == CHAP_MICROSOFT)? (mdtype) & MDTYPE_MICROSOFT: \
00120     ((digest) == CHAP_MD5)? (mdtype) & MDTYPE_MD5: \
00121     0
00122 #else /* !MSCHAP_SUPPORT */
00123 #define CHAP_CANDIGEST(mdtype, digest) \
00124     ((digest) == CHAP_MD5)? (mdtype) & MDTYPE_MD5: \
00125     0
00126 #endif /* MSCHAP_SUPPORT */
00127 
00128 /*
00129  * The code for each digest type has to supply one of these.
00130  */
00131 struct chap_digest_type {
00132     int code;
00133 
00134 #if PPP_SERVER
00135     /*
00136      * Note: challenge and response arguments below are formatted as
00137      * a length byte followed by the actual challenge/response data.
00138      */
00139     void (*generate_challenge)(ppp_pcb *pcb, unsigned char *challenge);
00140     int (*verify_response)(ppp_pcb *pcb, int id, const char *name,
00141         const unsigned char *secret, int secret_len,
00142         const unsigned char *challenge, const unsigned char *response,
00143         char *message, int message_space);
00144 #endif /* PPP_SERVER */
00145     void (*make_response)(ppp_pcb *pcb, unsigned char *response, int id, const char *our_name,
00146         const unsigned char *challenge, const char *secret, int secret_len,
00147         unsigned char *priv);
00148     int (*check_success)(ppp_pcb *pcb, unsigned char *pkt, int len, unsigned char *priv);
00149     void (*handle_failure)(ppp_pcb *pcb, unsigned char *pkt, int len);
00150 };
00151 
00152 /*
00153  * Each interface is described by chap structure.
00154  */
00155 #if CHAP_SUPPORT
00156 typedef struct chap_client_state {
00157     u8_t flags;
00158     const char *name;
00159     const struct chap_digest_type *digest;
00160     unsigned char priv[64];     /* private area for digest's use */
00161 } chap_client_state;
00162 
00163 #if PPP_SERVER
00164 typedef struct chap_server_state {
00165     u8_t flags;
00166     u8_t id;
00167     const char *name;
00168     const struct chap_digest_type *digest;
00169     int challenge_xmits;
00170     int challenge_pktlen;
00171     unsigned char challenge[CHAL_MAX_PKTLEN];
00172 } chap_server_state;
00173 #endif /* PPP_SERVER */
00174 #endif /* CHAP_SUPPORT */
00175 
00176 #if 0 /* UNUSED */
00177 /* Hook for a plugin to validate CHAP challenge */
00178 extern int (*chap_verify_hook)(char *name, char *ourname, int id,
00179             const struct chap_digest_type *digest,
00180             unsigned char *challenge, unsigned char *response,
00181             char *message, int message_space);
00182 #endif /* UNUSED */
00183 
00184 #if PPP_SERVER
00185 /* Called by authentication code to start authenticating the peer. */
00186 extern void chap_auth_peer(ppp_pcb *pcb, const char *our_name, int digest_code);
00187 #endif /* PPP_SERVER */
00188 
00189 /* Called by auth. code to start authenticating us to the peer. */
00190 extern void chap_auth_with_peer(ppp_pcb *pcb, const char *our_name, int digest_code);
00191 
00192 /* Represents the CHAP protocol to the main pppd code */
00193 extern const struct protent chap_protent;
00194 
00195 #ifdef __cplusplus
00196 }
00197 #endif
00198 
00199 #endif /* CHAP_H */
00200 #endif /* PPP_SUPPORT && CHAP_SUPPORT */