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. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * @(#)krb4encpwd.c     8.3 (Berkeley) 5/30/95
  34  * $FreeBSD: src/crypto/telnet/libtelnet/krb4encpwd.c,v 1.3.2.1 2002/04/13 10:59:07 markm Exp $
  35  * $DragonFly: src/crypto/telnet/libtelnet/krb4encpwd.c,v 1.2 2003/06/17 04:24:37 dillon Exp $
  36  */
  37
  38 #ifdef  KRB4_ENCPWD
  39 /*
  40  * COPYRIGHT (C) 1990 DIGITAL EQUIPMENT CORPORATION
  41  * ALL RIGHTS RESERVED
  42  *
  43  * "Digital Equipment Corporation authorizes the reproduction,
  44  * distribution and modification of this software subject to the following
  45  * restrictions:
  46  *
  47  * 1.  Any partial or whole copy of this software, or any modification
  48  * thereof, must include this copyright notice in its entirety.
  49  *
  50  * 2.  This software is supplied "as is" with no warranty of any kind,
  51  * expressed or implied, for any purpose, including any warranty of fitness
  52  * or merchantibility.  DIGITAL assumes no responsibility for the use or
  53  * reliability of this software, nor promises to provide any form of
  54  * support for it on any basis.
  55  *
  56  * 3.  Distribution of this software is authorized only if no profit or
  57  * remuneration of any kind is received in exchange for such distribution.
  58  *
  59  * 4.  This software produces public key authentication certificates
  60  * bearing an expiration date established by DIGITAL and RSA Data
  61  * Security, Inc.  It may cease to generate certificates after the expiration
  62  * date.  Any modification of this software that changes or defeats
  63  * the expiration date or its effect is unauthorized.
  64  *
  65  * 5.  Software that will renew or extend the expiration date of
  66  * authentication certificates produced by this software may be obtained
  67  * from RSA Data Security, Inc., 10 Twin Dolphin Drive, Redwood City, CA
  68  * 94065, (415)595-8782, or from DIGITAL"
  69  *
  70  */
  71
  72 #include <sys/types.h>
  73 #include <openssl/des.h>
  74 #include <arpa/telnet.h>
  75 #include <krb.h>
  76 #include <pwd.h>
  77 #include <stdio.h>
  78 #include <stdlib.h>
  79 #include <string.h>
  80
  81 #include "encrypt.h"
  82 #include "auth.h"
  83 #include "misc.h"
  84
  85 int krb_mk_encpwd_req(KTEXT, char *, char *, char *, char *, char *, char *);
  86 int krb_rd_encpwd_req(KTEXT, char *, char *, u_long, AUTH_DAT *, char *, char *, char *, char *);
  87
  88 extern auth_debug_mode;
  89
  90 static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0,
  91                                         AUTHTYPE_KRB4_ENCPWD, };
  92 static unsigned char str_name[1024] = { IAC, SB, TELOPT_AUTHENTICATION,
  93                                         TELQUAL_NAME, };
  94
  95 #define KRB4_ENCPWD_AUTH        0       /* Authentication data follows */
  96 #define KRB4_ENCPWD_REJECT      1       /* Rejected (reason might follow) */
  97 #define KRB4_ENCPWD_ACCEPT      2       /* Accepted */
  98 #define KRB4_ENCPWD_CHALLENGE   3       /* Challenge for mutual auth. */
  99 #define KRB4_ENCPWD_ACK         4       /* Acknowledge */
 100
 101 #define KRB_SERVICE_NAME    "rcmd"
 102
 103 static  KTEXT_ST auth;
 104 static  char name[ANAME_SZ];
 105 static  char user_passwd[ANAME_SZ];
 106 static  AUTH_DAT adat = { 0 };
 107 #ifdef  ENCRYPTION
 108 static Block    session_key     = { 0 };
 109 #endif  /* ENCRYPTION */
 110 static char  challenge[REALM_SZ];
 111
 112         static int
 113 Data(ap, type, d, c)
 114         Authenticator *ap;
 115         int type;
 116         void *d;
 117         int c;
 118 {
 119         unsigned char *p = str_data + 4;
 120         unsigned char *cd = (unsigned char *)d;
 121
 122         if (c == -1)
 123                 c = strlen((char *)cd);
 124
 125         if (0) {
 126                 printf("%s:%d: [%d] (%d)",
 127                         str_data[3] == TELQUAL_IS ? ">>>IS" : ">>>REPLY",
 128                         str_data[3],
 129                         type, c);
 130                 printd(d, c);
 131                 printf("\r\n");
 132         }
 133         *p++ = ap->type;
 134         *p++ = ap->way;
 135         *p++ = type;
 136         while (c-- > 0) {
 137                 if ((*p++ = *cd++) == IAC)
 138                         *p++ = IAC;
 139         }
 140         *p++ = IAC;
 141         *p++ = SE;
 142         if (str_data[3] == TELQUAL_IS)
 143                 printsub('>', &str_data[2], p - (&str_data[2]));
 144         return(net_write(str_data, p - str_data));
 145 }
 146
 147         int
 148 krb4encpwd_init(ap, server)
 149         Authenticator *ap;
 150         int server;
 151 {
 152         char hostname[80], *cp, *realm;
 153         C_Block skey;
 154
 155         if (server) {
 156                 str_data[3] = TELQUAL_REPLY;
 157         } else {
 158                 str_data[3] = TELQUAL_IS;
 159                 gethostname(hostname, sizeof(hostname));
 160                 realm = krb_realmofhost(hostname);
 161                 cp = strchr(hostname, '.');
 162                 if (*cp != NULL) *cp = NULL;
 163                 if (read_service_key(KRB_SERVICE_NAME, hostname, realm, 0,
 164                                         KEYFILE, (char *)skey)) {
 165                   return(0);
 166                 }
 167         }
 168         return(1);
 169 }
 170
 171         int
 172 krb4encpwd_send(ap)
 173         Authenticator *ap;
 174 {
 175
 176         printf("[ Trying KRB4ENCPWD ... ]\n");
 177         if (!UserNameRequested) {
 178                 return(0);
 179         }
 180         if (!auth_sendname(UserNameRequested, strlen(UserNameRequested))) {
 181                 return(0);
 182         }
 183
 184         if (!Data(ap, KRB4_ENCPWD_ACK, (void *)NULL, 0)) {
 185                 return(0);
 186         }
 187
 188         return(1);
 189 }
 190
 191         void
 192 krb4encpwd_is(ap, data, cnt)
 193         Authenticator *ap;
 194         unsigned char *data;
 195         int cnt;
 196 {
 197         Session_Key skey;
 198         Block datablock;
 199         char  r_passwd[ANAME_SZ], r_user[ANAME_SZ];
 200         char  lhostname[ANAME_SZ], *cp;
 201         int r;
 202         time_t now;
 203
 204         if (cnt-- < 1)
 205                 return;
 206         switch (*data++) {
 207         case KRB4_ENCPWD_AUTH:
 208                 memmove((void *)auth.dat, (void *)data, auth.length = cnt);
 209
 210                 gethostname(lhostname, sizeof(lhostname));
 211                 if ((cp = strchr(lhostname, '.')) != 0)  *cp = '\0';
 212
 213                 if (r = krb_rd_encpwd_req(&auth, KRB_SERVICE_NAME, lhostname, 0, &adat, NULL, challenge, r_user, r_passwd)) {
 214                         Data(ap, KRB4_ENCPWD_REJECT, (void *)"Auth failed", -1);
 215                         auth_finished(ap, AUTH_REJECT);
 216                         return;
 217                 }
 218                 auth_encrypt_userpwd(r_passwd);
 219                 if (passwdok(UserNameRequested, UserPassword) == 0) {
 220                   /*
 221                    *  illegal username and password
 222                    */
 223                   Data(ap, KRB4_ENCPWD_REJECT, (void *)"Illegal password", -1);
 224                   auth_finished(ap, AUTH_REJECT);
 225                   return;
 226                 }
 227
 228                 memmove((void *)session_key, (void *)adat.session, sizeof(Block));
 229                 Data(ap, KRB4_ENCPWD_ACCEPT, (void *)0, 0);
 230                 auth_finished(ap, AUTH_USER);
 231                 break;
 232
 233         case KRB4_ENCPWD_CHALLENGE:
 234                 /*
 235                  *  Take the received random challenge text and save
 236                  *  for future authentication.
 237                  */
 238                 memmove((void *)challenge, (void *)data, sizeof(Block));
 239                 break;
 240
 241
 242         case KRB4_ENCPWD_ACK:
 243                 /*
 244                  *  Receive ack, if mutual then send random challenge
 245                  */
 246
 247                 /*
 248                  * If we are doing mutual authentication, get set up to send
 249                  * the challenge, and verify it when the response comes back.
 250                  */
 251
 252                 if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) {
 253                   register int i;
 254
 255                   time(&now);
 256                   sprintf(challenge, "%x", now);
 257                   Data(ap, KRB4_ENCPWD_CHALLENGE, (void *)challenge, strlen(challenge));
 258                 }
 259                 break;
 260
 261         default:
 262                 Data(ap, KRB4_ENCPWD_REJECT, 0, 0);
 263                 break;
 264         }
 265 }
 266
 267
 268         void
 269 krb4encpwd_reply(ap, data, cnt)
 270         Authenticator *ap;
 271         unsigned char *data;
 272         int cnt;
 273 {
 274         Session_Key skey;
 275         KTEXT_ST krb_token;
 276         Block enckey;
 277         CREDENTIALS cred;
 278         int r;
 279         char    randchal[REALM_SZ], instance[ANAME_SZ], *cp;
 280         char    hostname[80], *realm;
 281
 282         if (cnt-- < 1)
 283                 return;
 284         switch (*data++) {
 285         case KRB4_ENCPWD_REJECT:
 286                 if (cnt > 0) {
 287                         printf("[ KRB4_ENCPWD refuses authentication because %.*s ]\r\n",
 288                                 cnt, data);
 289                 } else
 290                         printf("[ KRB4_ENCPWD refuses authentication ]\r\n");
 291                 auth_send_retry();
 292                 return;
 293         case KRB4_ENCPWD_ACCEPT:
 294                 printf("[ KRB4_ENCPWD accepts you ]\n");
 295                 auth_finished(ap, AUTH_USER);
 296                 return;
 297         case KRB4_ENCPWD_CHALLENGE:
 298                 /*
 299                  * Verify that the response to the challenge is correct.
 300                  */
 301
 302                 gethostname(hostname, sizeof(hostname));
 303                 realm = krb_realmofhost(hostname);
 304                 memmove((void *)challenge, (void *)data, cnt);
 305                 memset(user_passwd, 0, sizeof(user_passwd));
 306                 local_des_read_pw_string(user_passwd, sizeof(user_passwd)-1, "Password: ", 0);
 307                 UserPassword = user_passwd;
 308                 Challenge = challenge;
 309                 strcpy(instance, RemoteHostName);
 310                 if ((cp = strchr(instance, '.')) != 0)  *cp = '\0';
 311
 312                 if (r = krb_mk_encpwd_req(&krb_token, KRB_SERVICE_NAME, instance, realm, Challenge, UserNameRequested, user_passwd)) {
 313                   krb_token.length = 0;
 314                 }
 315
 316                 if (!Data(ap, KRB4_ENCPWD_AUTH, (void *)krb_token.dat, krb_token.length)) {
 317                   return;
 318                 }
 319
 320                 break;
 321
 322         default:
 323                 return;
 324         }
 325 }
 326
 327         int
 328 krb4encpwd_status(ap, name, level)
 329         Authenticator *ap;
 330         char *name;
 331         int level;
 332 {
 333
 334         if (level < AUTH_USER)
 335                 return(level);
 336
 337         if (UserNameRequested && passwdok(UserNameRequested, UserPassword)) {
 338                 strcpy(name, UserNameRequested);
 339                 return(AUTH_VALID);
 340         } else {
 341                 return(AUTH_USER);
 342         }
 343 }
 344
 345 #define BUMP(buf, len)          while (*(buf)) {++(buf), --(len);}
 346 #define ADDC(buf, len, c)       if ((len) > 0) {*(buf)++ = (c); --(len);}
 347
 348         void
 349 krb4encpwd_printsub(data, cnt, buf, buflen)
 350         unsigned char *data, *buf;
 351         int cnt, buflen;
 352 {
 353         char lbuf[32];
 354         register int i;
 355
 356         buf[buflen-1] = '\0';           /* make sure its NULL terminated */
 357         buflen -= 1;
 358
 359         switch(data[3]) {
 360         case KRB4_ENCPWD_REJECT:        /* Rejected (reason might follow) */
 361                 strncpy((char *)buf, " REJECT ", buflen);
 362                 goto common;
 363
 364         case KRB4_ENCPWD_ACCEPT:        /* Accepted (name might follow) */
 365                 strncpy((char *)buf, " ACCEPT ", buflen);
 366         common:
 367                 BUMP(buf, buflen);
 368                 if (cnt <= 4)
 369                         break;
 370                 ADDC(buf, buflen, '"');
 371                 for (i = 4; i < cnt; i++)
 372                         ADDC(buf, buflen, data[i]);
 373                 ADDC(buf, buflen, '"');
 374                 ADDC(buf, buflen, '\0');
 375                 break;
 376
 377         case KRB4_ENCPWD_AUTH:          /* Authentication data follows */
 378                 strncpy((char *)buf, " AUTH", buflen);
 379                 goto common2;
 380
 381         case KRB4_ENCPWD_CHALLENGE:
 382                 strncpy((char *)buf, " CHALLENGE", buflen);
 383                 goto common2;
 384
 385         case KRB4_ENCPWD_ACK:
 386                 strncpy((char *)buf, " ACK", buflen);
 387                 goto common2;
 388
 389         default:
 390                 sprintf(lbuf, " %d (unknown)", data[3]);
 391                 strncpy((char *)buf, lbuf, buflen);
 392         common2:
 393                 BUMP(buf, buflen);
 394                 for (i = 4; i < cnt; i++) {
 395                         sprintf(lbuf, " %d", data[i]);
 396                         strncpy((char *)buf, lbuf, buflen);
 397                         BUMP(buf, buflen);
 398                 }
 399                 break;
 400         }
 401 }
 402
 403 int passwdok(name, passwd)
 404 char *name, *passwd;
 405 {
 406   char *crypt();
 407   char *salt, *p;
 408   struct passwd *pwd;
 409   int   passwdok_status = 0;
 410
 411   if (pwd = getpwnam(name))
 412     salt = pwd->pw_passwd;
 413   else salt = "xx";
 414
 415   p = crypt(passwd, salt);
 416
 417   if (pwd && !strcmp(p, pwd->pw_passwd)) {
 418     passwdok_status = 1;
 419   } else passwdok_status = 0;
 420   return(passwdok_status);
 421 }
 422
 423 #endif