lib/libtelnet/rsaencpwd.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  * @(#)rsaencpwd.c      8.3 (Berkeley) 5/30/95
  30  * $FreeBSD: src/crypto/telnet/libtelnet/rsaencpwd.c,v 1.1.1.1.8.1 2002/04/13 10:59:07 markm Exp $
  31  */
  32
  33 #ifdef  RSA_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 merchantibility.  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 <arpa/telnet.h>
  69 #include <pwd.h>
  70 #include <stdio.h>
  71 #include <stdlib.h>
  72 #include <string.h>
  73
  74 #include "encrypt.h"
  75 #include "auth.h"
  76 #include "misc.h"
  77 #include "cdc.h"
  78
  79 extern auth_debug_mode;
  80
  81 static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0,
  82                                         AUTHTYPE_RSA_ENCPWD, };
  83 static unsigned char str_name[1024] = { IAC, SB, TELOPT_AUTHENTICATION,
  84                                         TELQUAL_NAME, };
  85
  86 #define RSA_ENCPWD_AUTH 0       /* Authentication data follows */
  87 #define RSA_ENCPWD_REJECT       1       /* Rejected (reason might follow) */
  88 #define RSA_ENCPWD_ACCEPT       2       /* Accepted */
  89 #define RSA_ENCPWD_CHALLENGEKEY 3       /* Challenge and public key */
  90
  91 #define NAME_SZ   40
  92 #define CHAL_SZ   20
  93 #define PWD_SZ    40
  94
  95 static  KTEXT_ST auth;
  96 static  char name[NAME_SZ];
  97 static  char user_passwd[PWD_SZ];
  98 static  char key_file[2*NAME_SZ];
  99 static  char lhostname[NAME_SZ];
 100 static char  challenge[CHAL_SZ];
 101 static int   challenge_len;
 102
 103         static int
 104 Data(ap, type, d, c)
 105         Authenticator *ap;
 106         int type;
 107         void *d;
 108         int c;
 109 {
 110         unsigned char *p = str_data + 4;
 111         unsigned char *cd = (unsigned char *)d;
 112
 113         if (c == -1)
 114                 c = strlen((char *)cd);
 115
 116         if (0) {
 117                 printf("%s:%d: [%d] (%d)",
 118                         str_data[3] == TELQUAL_IS ? ">>>IS" : ">>>REPLY",
 119                         str_data[3],
 120                         type, c);
 121                 printd(d, c);
 122                 printf("\r\n");
 123         }
 124         *p++ = ap->type;
 125         *p++ = ap->way;
 126         if (type != NULL) *p++ = type;
 127         while (c-- > 0) {
 128                 if ((*p++ = *cd++) == IAC)
 129                         *p++ = IAC;
 130         }
 131         *p++ = IAC;
 132         *p++ = SE;
 133         if (str_data[3] == TELQUAL_IS)
 134                 printsub('>', &str_data[2], p - (&str_data[2]));
 135         return(net_write(str_data, p - str_data));
 136 }
 137
 138         int
 139 rsaencpwd_init(ap, server)
 140         Authenticator *ap;
 141         int server;
 142 {
 143         char  *cp;
 144         FILE  *fp;
 145
 146         if (server) {
 147                 str_data[3] = TELQUAL_REPLY;
 148                 memset(key_file, 0, sizeof(key_file));
 149                 gethostname(lhostname, sizeof(lhostname));
 150                 if ((cp = strchr(lhostname, '.')) != NULL)  *cp = '\0';
 151                 strcpy(key_file, "/etc/.");
 152                 strcat(key_file, lhostname);
 153                 strcat(key_file, "_privkey");
 154                 if ((fp=fopen(key_file, "r"))==NULL) return(0);
 155                 fclose(fp);
 156         } else {
 157                 str_data[3] = TELQUAL_IS;
 158         }
 159         return(1);
 160 }
 161
 162         int
 163 rsaencpwd_send(ap)
 164         Authenticator *ap;
 165 {
 166
 167         printf("[ Trying RSAENCPWD ... ]\n");
 168         if (!UserNameRequested) {
 169                 return(0);
 170         }
 171         if (!auth_sendname(UserNameRequested, strlen(UserNameRequested))) {
 172                 return(0);
 173         }
 174         if (!Data(ap, NULL, NULL, 0)) {
 175                 return(0);
 176         }
 177
 178
 179         return(1);
 180 }
 181
 182         void
 183 rsaencpwd_is(ap, data, cnt)
 184         Authenticator *ap;
 185         unsigned char *data;
 186         int cnt;
 187 {
 188         char  r_passwd[PWD_SZ];
 189         char  key[160];
 190         char  chalkey[160], *ptr;
 191         FILE  *fp;
 192         int r, i, j, chalkey_len, len;
 193         time_t now;
 194
 195         cnt--;
 196         switch (*data++) {
 197         case RSA_ENCPWD_AUTH:
 198                 memmove((void *)auth.dat, (void *)data, auth.length = cnt);
 199
 200                 if ((fp=fopen(key_file, "r"))==NULL) {
 201                   Data(ap, RSA_ENCPWD_REJECT, (void *)"Auth failed", -1);
 202                   auth_finished(ap, AUTH_REJECT);
 203                   return;
 204                 }
 205                 /*
 206                  *  get privkey
 207                  */
 208                 fscanf(fp, "%x;", &len);
 209                 for (i=0;i<len;i++) {
 210                   j = getc(fp);  key[i]=j;
 211                 }
 212                 fclose(fp);
 213
 214                 r = accept_rsa_encpwd(&auth, key, challenge,
 215                                       challenge_len, r_passwd);
 216                 if (r < 0) {
 217                   Data(ap, RSA_ENCPWD_REJECT, (void *)"Auth failed", -1);
 218                   auth_finished(ap, AUTH_REJECT);
 219                   return;
 220                 }
 221                 auth_encrypt_userpwd(r_passwd);
 222                 if (rsaencpwd_passwdok(UserNameRequested, UserPassword) == 0) {
 223                   /*
 224                    *  illegal username and password
 225                    */
 226                   Data(ap, RSA_ENCPWD_REJECT, (void *)"Illegal password", -1);
 227                   auth_finished(ap, AUTH_REJECT);
 228                   return;
 229                 }
 230
 231                 Data(ap, RSA_ENCPWD_ACCEPT, (void *)0, 0);
 232                 auth_finished(ap, AUTH_USER);
 233                 break;
 234
 235
 236         case IAC:
 237
 238                 /*
 239                  * If we are doing mutual authentication, get set up to send
 240                  * the challenge, and verify it when the response comes back.
 241                  */
 242                 if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_ONE_WAY) {
 243                   register int i;
 244
 245
 246                   time(&now);
 247                   if ((now % 2) == 0) {
 248                     sprintf(challenge, "%x", now);
 249                     challenge_len = strlen(challenge);
 250                   } else {
 251                     strcpy(challenge, "randchal");
 252                     challenge_len = 8;
 253                   }
 254
 255                   if ((fp=fopen(key_file, "r"))==NULL) {
 256                     Data(ap, RSA_ENCPWD_REJECT, (void *)"Auth failed", -1);
 257                     auth_finished(ap, AUTH_REJECT);
 258                     return;
 259                   }
 260                   /*
 261                    *  skip privkey
 262                    */
 263                   fscanf(fp, "%x;", &len);
 264                   for (i=0;i<len;i++) {
 265                     j = getc(fp);
 266                   }
 267                   /*
 268                    * get pubkey
 269                    */
 270                   fscanf(fp, "%x;", &len);
 271                   for (i=0;i<len;i++) {
 272                     j = getc(fp);  key[i]=j;
 273                   }
 274                   fclose(fp);
 275                   chalkey[0] = 0x30;
 276                   ptr = (char *) &chalkey[1];
 277                   chalkey_len = 1+NumEncodeLengthOctets(i)+i+1+NumEncodeLengthOctets(challenge_len)+challenge_len;
 278                   EncodeLength(ptr, chalkey_len);
 279                   ptr +=NumEncodeLengthOctets(chalkey_len);
 280                   *ptr++ = 0x04;  /* OCTET STRING */
 281                   *ptr++ = challenge_len;
 282                   memmove(ptr, challenge, challenge_len);
 283                   ptr += challenge_len;
 284                   *ptr++ = 0x04;  /* OCTET STRING */
 285                   EncodeLength(ptr, i);
 286                   ptr += NumEncodeLengthOctets(i);
 287                   memmove(ptr, key, i);
 288                   chalkey_len = 1+NumEncodeLengthOctets(chalkey_len)+chalkey_len;
 289                   Data(ap, RSA_ENCPWD_CHALLENGEKEY, (void *)chalkey, chalkey_len);
 290                 }
 291                 break;
 292
 293         default:
 294                 Data(ap, RSA_ENCPWD_REJECT, 0, 0);
 295                 break;
 296         }
 297 }
 298
 299
 300         void
 301 rsaencpwd_reply(ap, data, cnt)
 302         Authenticator *ap;
 303         unsigned char *data;
 304         int cnt;
 305 {
 306         KTEXT_ST token;
 307         int r, pubkey_len;
 308         char    chalkey[160], pubkey[128], *ptr;
 309
 310         if (cnt-- < 1)
 311                 return;
 312         switch (*data++) {
 313         case RSA_ENCPWD_REJECT:
 314                 if (cnt > 0) {
 315                         printf("[ RSA_ENCPWD refuses authentication because %.*s ]\r\n",
 316                                 cnt, data);
 317                 } else
 318                         printf("[ RSA_ENCPWD refuses authentication ]\r\n");
 319                 auth_send_retry();
 320                 return;
 321         case RSA_ENCPWD_ACCEPT:
 322                 printf("[ RSA_ENCPWD accepts you ]\n");
 323                 auth_finished(ap, AUTH_USER);
 324                 return;
 325         case RSA_ENCPWD_CHALLENGEKEY:
 326                 /*
 327                  * Verify that the response to the challenge is correct.
 328                  */
 329
 330                 memmove((void *)chalkey, (void *)data, cnt);
 331                 ptr = (char *) &chalkey[0];
 332                 ptr += DecodeHeaderLength(chalkey);
 333                 if (*ptr != 0x04) {
 334                   return;
 335                 }
 336                 *ptr++;
 337                 challenge_len = DecodeValueLength(ptr);
 338                 ptr += NumEncodeLengthOctets(challenge_len);
 339                 memmove(challenge, ptr, challenge_len);
 340                 ptr += challenge_len;
 341                 if (*ptr != 0x04) {
 342                   return;
 343                 }
 344                 *ptr++;
 345                 pubkey_len = DecodeValueLength(ptr);
 346                 ptr += NumEncodeLengthOctets(pubkey_len);
 347                 memmove(pubkey, ptr, pubkey_len);
 348                 memset(user_passwd, 0, sizeof(user_passwd));
 349                 local_des_read_pw_string(user_passwd, sizeof(user_passwd)-1, "Password: ", 0);
 350                 UserPassword = user_passwd;
 351                 Challenge = challenge;
 352                 r = init_rsa_encpwd(&token, user_passwd, challenge, challenge_len, pubkey);
 353                 if (r < 0) {
 354                   token.length = 1;
 355                 }
 356
 357                 if (!Data(ap, RSA_ENCPWD_AUTH, (void *)token.dat, token.length)) {
 358                   return;
 359                 }
 360
 361                 break;
 362
 363         default:
 364                 return;
 365         }
 366 }
 367
 368         int
 369 rsaencpwd_status(ap, name, level)
 370         Authenticator *ap;
 371         char *name;
 372         int level;
 373 {
 374
 375         if (level < AUTH_USER)
 376                 return(level);
 377
 378         if (UserNameRequested && rsaencpwd_passwdok(UserNameRequested, UserPassword)) {
 379                 strcpy(name, UserNameRequested);
 380                 return(AUTH_VALID);
 381         } else {
 382                 return(AUTH_USER);
 383         }
 384 }
 385
 386 #define BUMP(buf, len)          while (*(buf)) {++(buf), --(len);}
 387 #define ADDC(buf, len, c)       if ((len) > 0) {*(buf)++ = (c); --(len);}
 388
 389         void
 390 rsaencpwd_printsub(data, cnt, buf, buflen)
 391         unsigned char *data, *buf;
 392         int cnt, buflen;
 393 {
 394         char lbuf[32];
 395         register int i;
 396
 397         buf[buflen-1] = '\0';           /* make sure its NULL terminated */
 398         buflen -= 1;
 399
 400         switch(data[3]) {
 401         case RSA_ENCPWD_REJECT: /* Rejected (reason might follow) */
 402                 strncpy((char *)buf, " REJECT ", buflen);
 403                 goto common;
 404
 405         case RSA_ENCPWD_ACCEPT: /* Accepted (name might follow) */
 406                 strncpy((char *)buf, " ACCEPT ", buflen);
 407         common:
 408                 BUMP(buf, buflen);
 409                 if (cnt <= 4)
 410                         break;
 411                 ADDC(buf, buflen, '"');
 412                 for (i = 4; i < cnt; i++)
 413                         ADDC(buf, buflen, data[i]);
 414                 ADDC(buf, buflen, '"');
 415                 ADDC(buf, buflen, '\0');
 416                 break;
 417
 418         case RSA_ENCPWD_AUTH:           /* Authentication data follows */
 419                 strncpy((char *)buf, " AUTH", buflen);
 420                 goto common2;
 421
 422         case RSA_ENCPWD_CHALLENGEKEY:
 423                 strncpy((char *)buf, " CHALLENGEKEY", buflen);
 424                 goto common2;
 425
 426         default:
 427                 sprintf(lbuf, " %d (unknown)", data[3]);
 428                 strncpy((char *)buf, lbuf, buflen);
 429         common2:
 430                 BUMP(buf, buflen);
 431                 for (i = 4; i < cnt; i++) {
 432                         sprintf(lbuf, " %d", data[i]);
 433                         strncpy((char *)buf, lbuf, buflen);
 434                         BUMP(buf, buflen);
 435                 }
 436                 break;
 437         }
 438 }
 439
 440 int rsaencpwd_passwdok(name, passwd)
 441 char *name, *passwd;
 442 {
 443   char *crypt();
 444   char *salt, *p;
 445   struct passwd *pwd;
 446   int   passwdok_status = 0;
 447
 448   if (pwd = getpwnam(name))
 449     salt = pwd->pw_passwd;
 450   else salt = "xx";
 451
 452   p = crypt(passwd, salt);
 453
 454   if (pwd && !strcmp(p, pwd->pw_passwd)) {
 455     passwdok_status = 1;
 456   } else passwdok_status = 0;
 457   return(passwdok_status);
 458 }
 459
 460 #endif