lib/libtelnet/krb4encpwd.c

   1 /*-
   2  * Copyright (c) 1992, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  * @(#)krb4encpwd.c     8.3 (Berkeley) 5/30/95
  30  * $FreeBSD: src/crypto/telnet/libtelnet/krb4encpwd.c,v 1.3.2.1 2002/04/13 10:59:07 markm Exp $
  31  */
  32
  33 #ifdef  KRB4_ENCPWD
  34 /*
  35  * COPYRIGHT (C) 1990 DIGITAL EQUIPMENT CORPORATION
  36  * ALL RIGHTS RESERVED
  37  *
  38  * "Digital Equipment Corporation authorizes the reproduction,
  39  * distribution and modification of this software subject to the following
  40  * restrictions:
  41  *
  42  * 1.  Any partial or whole copy of this software, or any modification
  43  * thereof, must include this copyright notice in its entirety.
  44  *
  45  * 2.  This software is supplied "as is" with no warranty of any kind,
  46  * expressed or implied, for any purpose, including any warranty of fitness
  47  * or merchantability.  DIGITAL assumes no responsibility for the use or
  48  * reliability of this software, nor promises to provide any form of
  49  * support for it on any basis.
  50  *
  51  * 3.  Distribution of this software is authorized only if no profit or
  52  * remuneration of any kind is received in exchange for such distribution.
  53  *
  54  * 4.  This software produces public key authentication certificates
  55  * bearing an expiration date established by DIGITAL and RSA Data
  56  * Security, Inc.  It may cease to generate certificates after the expiration
  57  * date.  Any modification of this software that changes or defeats
  58  * the expiration date or its effect is unauthorized.
  59  *
  60  * 5.  Software that will renew or extend the expiration date of
  61  * authentication certificates produced by this software may be obtained
  62  * from RSA Data Security, Inc., 10 Twin Dolphin Drive, Redwood City, CA
  63  * 94065, (415)595-8782, or from DIGITAL"
  64  *
  65  */
  66
  67 #include <sys/types.h>
  68 #include <openssl/des.h>
  69 #include <arpa/telnet.h>
  70 #include <krb.h>
  71 #include <pwd.h>
  72 #include <stdio.h>
  73 #include <stdlib.h>
  74 #include <string.h>
  75
  76 #include "encrypt.h"
  77 #include "auth.h"
  78 #include "misc.h"
  79
  80 int krb_mk_encpwd_req(KTEXT, char *, char *, char *, char *, char *, char *);
  81 int krb_rd_encpwd_req(KTEXT, char *, char *, u_long, AUTH_DAT *, char *, char *, char *, char *);
  82
  83 extern auth_debug_mode;
  84
  85 static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0,
  86                                         AUTHTYPE_KRB4_ENCPWD, };
  87 static unsigned char str_name[1024] = { IAC, SB, TELOPT_AUTHENTICATION,
  88                                         TELQUAL_NAME, };
  89
  90 #define KRB4_ENCPWD_AUTH        0       /* Authentication data follows */
  91 #define KRB4_ENCPWD_REJECT      1       /* Rejected (reason might follow) */
  92 #define KRB4_ENCPWD_ACCEPT      2       /* Accepted */
  93 #define KRB4_ENCPWD_CHALLENGE   3       /* Challenge for mutual auth. */
  94 #define KRB4_ENCPWD_ACK         4       /* Acknowledge */
  95
  96 #define KRB_SERVICE_NAME    "rcmd"
  97
  98 static  KTEXT_ST auth;
  99 static  char name[ANAME_SZ];
 100 static  char user_passwd[ANAME_SZ];
 101 static  AUTH_DAT adat = { 0 };
 102 #ifdef  ENCRYPTION
 103 static Block    session_key     = { 0 };
 104 #endif  /* ENCRYPTION */
 105 static char  challenge[REALM_SZ];
 106
 107         static int
 108 Data(ap, type, d, c)
 109         Authenticator *ap;
 110         int type;
 111         void *d;
 112         int c;
 113 {
 114         unsigned char *p = str_data + 4;
 115         unsigned char *cd = (unsigned char *)d;
 116
 117         if (c == -1)
 118                 c = strlen((char *)cd);
 119
 120         if (0) {
 121                 printf("%s:%d: [%d] (%d)",
 122                         str_data[3] == TELQUAL_IS ? ">>>IS" : ">>>REPLY",
 123                         str_data[3],
 124                         type, c);
 125                 printd(d, c);
 126                 printf("\r\n");
 127         }
 128         *p++ = ap->type;
 129         *p++ = ap->way;
 130         *p++ = type;
 131         while (c-- > 0) {
 132                 if ((*p++ = *cd++) == IAC)
 133                         *p++ = IAC;
 134         }
 135         *p++ = IAC;
 136         *p++ = SE;
 137         if (str_data[3] == TELQUAL_IS)
 138                 printsub('>', &str_data[2], p - (&str_data[2]));
 139         return(net_write(str_data, p - str_data));
 140 }
 141
 142         int
 143 krb4encpwd_init(ap, server)
 144         Authenticator *ap;
 145         int server;
 146 {
 147         char hostname[80], *cp, *realm;
 148         C_Block skey;
 149
 150         if (server) {
 151                 str_data[3] = TELQUAL_REPLY;
 152         } else {
 153                 str_data[3] = TELQUAL_IS;
 154                 gethostname(hostname, sizeof(hostname));
 155                 realm = krb_realmofhost(hostname);
 156                 cp = strchr(hostname, '.');
 157                 if (*cp != NULL) *cp = NULL;
 158                 if (read_service_key(KRB_SERVICE_NAME, hostname, realm, 0,
 159                                         KEYFILE, (char *)skey)) {
 160                   return(0);
 161                 }
 162         }
 163         return(1);
 164 }
 165
 166         int
 167 krb4encpwd_send(ap)
 168         Authenticator *ap;
 169 {
 170
 171         printf("[ Trying KRB4ENCPWD ... ]\n");
 172         if (!UserNameRequested) {
 173                 return(0);
 174         }
 175         if (!auth_sendname(UserNameRequested, strlen(UserNameRequested))) {
 176                 return(0);
 177         }
 178
 179         if (!Data(ap, KRB4_ENCPWD_ACK, NULL, 0)) {
 180                 return(0);
 181         }
 182
 183         return(1);
 184 }
 185
 186         void
 187 krb4encpwd_is(ap, data, cnt)
 188         Authenticator *ap;
 189         unsigned char *data;
 190         int cnt;
 191 {
 192         char  r_passwd[ANAME_SZ], r_user[ANAME_SZ];
 193         char  lhostname[ANAME_SZ], *cp;
 194         int r;
 195         time_t now;
 196
 197         if (cnt-- < 1)
 198                 return;
 199         switch (*data++) {
 200         case KRB4_ENCPWD_AUTH:
 201                 memmove((void *)auth.dat, (void *)data, auth.length = cnt);
 202
 203                 gethostname(lhostname, sizeof(lhostname));
 204                 if ((cp = strchr(lhostname, '.')) != NULL)  *cp = '\0';
 205
 206                 if (r = krb_rd_encpwd_req(&auth, KRB_SERVICE_NAME, lhostname, 0, &adat, NULL, challenge, r_user, r_passwd)) {
 207                         Data(ap, KRB4_ENCPWD_REJECT, (void *)"Auth failed", -1);
 208                         auth_finished(ap, AUTH_REJECT);
 209                         return;
 210                 }
 211                 auth_encrypt_userpwd(r_passwd);
 212                 if (passwdok(UserNameRequested, UserPassword) == 0) {
 213                   /*
 214                    *  illegal username and password
 215                    */
 216                   Data(ap, KRB4_ENCPWD_REJECT, (void *)"Illegal password", -1);
 217                   auth_finished(ap, AUTH_REJECT);
 218                   return;
 219                 }
 220
 221                 memmove((void *)session_key, (void *)adat.session, sizeof(Block));
 222                 Data(ap, KRB4_ENCPWD_ACCEPT, (void *)0, 0);
 223                 auth_finished(ap, AUTH_USER);
 224                 break;
 225
 226         case KRB4_ENCPWD_CHALLENGE:
 227                 /*
 228                  *  Take the received random challenge text and save
 229                  *  for future authentication.
 230                  */
 231                 memmove((void *)challenge, (void *)data, sizeof(Block));
 232                 break;
 233
 234
 235         case KRB4_ENCPWD_ACK:
 236                 /*
 237                  *  Receive ack, if mutual then send random challenge
 238                  */
 239
 240                 /*
 241                  * If we are doing mutual authentication, get set up to send
 242                  * the challenge, and verify it when the response comes back.
 243                  */
 244
 245                 if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) {
 246                   time(&now);
 247                   sprintf(challenge, "%x", now);
 248                   Data(ap, KRB4_ENCPWD_CHALLENGE, (void *)challenge, strlen(challenge));
 249                 }
 250                 break;
 251
 252         default:
 253                 Data(ap, KRB4_ENCPWD_REJECT, 0, 0);
 254                 break;
 255         }
 256 }
 257
 258
 259         void
 260 krb4encpwd_reply(ap, data, cnt)
 261         Authenticator *ap;
 262         unsigned char *data;
 263         int cnt;
 264 {
 265         KTEXT_ST krb_token;
 266         int r;
 267         char    instance[ANAME_SZ], *cp;
 268         char    hostname[80], *realm;
 269
 270         if (cnt-- < 1)
 271                 return;
 272         switch (*data++) {
 273         case KRB4_ENCPWD_REJECT:
 274                 if (cnt > 0) {
 275                         printf("[ KRB4_ENCPWD refuses authentication because %.*s ]\r\n",
 276                                 cnt, data);
 277                 } else
 278                         printf("[ KRB4_ENCPWD refuses authentication ]\r\n");
 279                 auth_send_retry();
 280                 return;
 281         case KRB4_ENCPWD_ACCEPT:
 282                 printf("[ KRB4_ENCPWD accepts you ]\n");
 283                 auth_finished(ap, AUTH_USER);
 284                 return;
 285         case KRB4_ENCPWD_CHALLENGE:
 286                 /*
 287                  * Verify that the response to the challenge is correct.
 288                  */
 289
 290                 gethostname(hostname, sizeof(hostname));
 291                 realm = krb_realmofhost(hostname);
 292                 memmove((void *)challenge, (void *)data, cnt);
 293                 memset(user_passwd, 0, sizeof(user_passwd));
 294                 local_des_read_pw_string(user_passwd, sizeof(user_passwd)-1, "Password: ", 0);
 295                 UserPassword = user_passwd;
 296                 Challenge = challenge;
 297                 strcpy(instance, RemoteHostName);
 298                 if ((cp = strchr(instance, '.')) != NULL)  *cp = '\0';
 299
 300                 if (r = krb_mk_encpwd_req(&krb_token, KRB_SERVICE_NAME, instance, realm, Challenge, UserNameRequested, user_passwd)) {
 301                   krb_token.length = 0;
 302                 }
 303
 304                 if (!Data(ap, KRB4_ENCPWD_AUTH, (void *)krb_token.dat, krb_token.length)) {
 305                   return;
 306                 }
 307
 308                 break;
 309
 310         default:
 311                 return;
 312         }
 313 }
 314
 315         int
 316 krb4encpwd_status(ap, name, level)
 317         Authenticator *ap;
 318         char *name;
 319         int level;
 320 {
 321
 322         if (level < AUTH_USER)
 323                 return(level);
 324
 325         if (UserNameRequested && passwdok(UserNameRequested, UserPassword)) {
 326                 strcpy(name, UserNameRequested);
 327                 return(AUTH_VALID);
 328         } else {
 329                 return(AUTH_USER);
 330         }
 331 }
 332
 333 #define BUMP(buf, len)          while (*(buf)) {++(buf), --(len);}
 334 #define ADDC(buf, len, c)       if ((len) > 0) {*(buf)++ = (c); --(len);}
 335
 336         void
 337 krb4encpwd_printsub(data, cnt, buf, buflen)
 338         unsigned char *data, *buf;
 339         int cnt, buflen;
 340 {
 341         char lbuf[32];
 342         register int i;
 343
 344         buf[buflen-1] = '\0';           /* make sure its NULL terminated */
 345         buflen -= 1;
 346
 347         switch(data[3]) {
 348         case KRB4_ENCPWD_REJECT:        /* Rejected (reason might follow) */
 349                 strncpy((char *)buf, " REJECT ", buflen);
 350                 goto common;
 351
 352         case KRB4_ENCPWD_ACCEPT:        /* Accepted (name might follow) */
 353                 strncpy((char *)buf, " ACCEPT ", buflen);
 354         common:
 355                 BUMP(buf, buflen);
 356                 if (cnt <= 4)
 357                         break;
 358                 ADDC(buf, buflen, '"');
 359                 for (i = 4; i < cnt; i++)
 360                         ADDC(buf, buflen, data[i]);
 361                 ADDC(buf, buflen, '"');
 362                 ADDC(buf, buflen, '\0');
 363                 break;
 364
 365         case KRB4_ENCPWD_AUTH:          /* Authentication data follows */
 366                 strncpy((char *)buf, " AUTH", buflen);
 367                 goto common2;
 368
 369         case KRB4_ENCPWD_CHALLENGE:
 370                 strncpy((char *)buf, " CHALLENGE", buflen);
 371                 goto common2;
 372
 373         case KRB4_ENCPWD_ACK:
 374                 strncpy((char *)buf, " ACK", buflen);
 375                 goto common2;
 376
 377         default:
 378                 sprintf(lbuf, " %d (unknown)", data[3]);
 379                 strncpy((char *)buf, lbuf, buflen);
 380         common2:
 381                 BUMP(buf, buflen);
 382                 for (i = 4; i < cnt; i++) {
 383                         sprintf(lbuf, " %d", data[i]);
 384                         strncpy((char *)buf, lbuf, buflen);
 385                         BUMP(buf, buflen);
 386                 }
 387                 break;
 388         }
 389 }
 390
 391 int passwdok(name, passwd)
 392 char *name, *passwd;
 393 {
 394   char *crypt();
 395   char *salt, *p;
 396   struct passwd *pwd;
 397   int   passwdok_status = 0;
 398
 399   if (pwd = getpwnam(name))
 400     salt = pwd->pw_passwd;
 401   else salt = "xx";
 402
 403   p = crypt(passwd, salt);
 404
 405   if (pwd && !strcmp(p, pwd->pw_passwd)) {
 406     passwdok_status = 1;
 407   } else passwdok_status = 0;
 408   return(passwdok_status);
 409 }
 410
 411 #endif