lib/libtelnet/auth.c

   1 /*-
   2  * Copyright (c) 1991, 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  * $FreeBSD: src/crypto/telnet/libtelnet/auth.c,v 1.3.2.5 2002/04/13 10:59:07 markm Exp $
  34  *
  35  * @(#)auth.c   8.3 (Berkeley) 5/30/95
  36  * $FreeBSD: src/crypto/telnet/libtelnet/auth.c,v 1.3.2.5 2002/04/13 10:59:07 markm Exp $
  37  */
  38
  39 /*
  40  * Copyright (C) 1990 by the Massachusetts Institute of Technology
  41  *
  42  * Export of this software from the United States of America is assumed
  43  * to require a specific license from the United States Government.
  44  * It is the responsibility of any person or organization contemplating
  45  * export to obtain such a license before exporting.
  46  *
  47  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
  48  * distribute this software and its documentation for any purpose and
  49  * without fee is hereby granted, provided that the above copyright
  50  * notice appear in all copies and that both that copyright notice and
  51  * this permission notice appear in supporting documentation, and that
  52  * the name of M.I.T. not be used in advertising or publicity pertaining
  53  * to distribution of the software without specific, written prior
  54  * permission.  M.I.T. makes no representations about the suitability of
  55  * this software for any purpose.  It is provided "as is" without express
  56  * or implied warranty.
  57  */
  58
  59
  60 #ifdef  AUTHENTICATION
  61 #define AUTH_NAMES
  62 #include <sys/types.h>
  63 #include <signal.h>
  64 #include <stdio.h>
  65 #include <stdlib.h>
  66 #include <string.h>
  67 #include <unistd.h>
  68 #include <arpa/telnet.h>
  69
  70 #include "encrypt.h"
  71 #include "auth.h"
  72 #include "misc-proto.h"
  73 #include "auth-proto.h"
  74
  75 #define typemask(x)     ((x) > 0 ? 1 << ((x)-1) : 0)
  76
  77 #ifdef  KRB4_ENCPWD
  78 extern krb4encpwd_init();
  79 extern krb4encpwd_send();
  80 extern krb4encpwd_is();
  81 extern krb4encpwd_reply();
  82 extern krb4encpwd_status();
  83 extern krb4encpwd_printsub();
  84 #endif
  85
  86 #ifdef  RSA_ENCPWD
  87 extern rsaencpwd_init();
  88 extern rsaencpwd_send();
  89 extern rsaencpwd_is();
  90 extern rsaencpwd_reply();
  91 extern rsaencpwd_status();
  92 extern rsaencpwd_printsub();
  93 #endif
  94
  95 int auth_debug_mode = 0;
  96 static  const char      *Name = "Noname";
  97 static  int     Server = 0;
  98 static  Authenticator   *authenticated = NULL;
  99 static  int     authenticating = 0;
 100 static  int     validuser = 0;
 101 static  unsigned char   _auth_send_data[256];
 102 static  unsigned char   *auth_send_data;
 103 static  int     auth_send_cnt = 0;
 104
 105 int auth_onoff(char *type, int on);
 106 void auth_encrypt_user(char *name);
 107
 108 /*
 109  * Authentication types supported.  Plese note that these are stored
 110  * in priority order, i.e. try the first one first.
 111  */
 112 Authenticator authenticators[] = {
 113 #ifdef  KRB5
 114 # ifdef ENCRYPTION
 115         { AUTHTYPE_KERBEROS_V5, AUTH_WHO_CLIENT|AUTH_HOW_MUTUAL,
 116                                 kerberos5_init,
 117                                 kerberos5_send_mutual,
 118                                 kerberos5_is,
 119                                 kerberos5_reply,
 120                                 kerberos5_status,
 121                                 kerberos5_printsub },
 122 # endif /* ENCRYPTION */
 123         { AUTHTYPE_KERBEROS_V5, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
 124                                 kerberos5_init,
 125                                 kerberos5_send_oneway,
 126                                 kerberos5_is,
 127                                 kerberos5_reply,
 128                                 kerberos5_status,
 129                                 kerberos5_printsub },
 130 #endif
 131 #ifdef  KRB4
 132 # ifdef ENCRYPTION
 133         { AUTHTYPE_KERBEROS_V4, AUTH_WHO_CLIENT|AUTH_HOW_MUTUAL,
 134                                 kerberos4_init,
 135                                 kerberos4_send,
 136                                 kerberos4_is,
 137                                 kerberos4_reply,
 138                                 kerberos4_status,
 139                                 kerberos4_printsub },
 140 # endif /* ENCRYPTION */
 141         { AUTHTYPE_KERBEROS_V4, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
 142                                 kerberos4_init,
 143                                 kerberos4_send,
 144                                 kerberos4_is,
 145                                 kerberos4_reply,
 146                                 kerberos4_status,
 147                                 kerberos4_printsub },
 148 #endif
 149 #ifdef  KRB4_ENCPWD
 150         { AUTHTYPE_KRB4_ENCPWD, AUTH_WHO_CLIENT|AUTH_HOW_MUTUAL,
 151                                 krb4encpwd_init,
 152                                 krb4encpwd_send,
 153                                 krb4encpwd_is,
 154                                 krb4encpwd_reply,
 155                                 krb4encpwd_status,
 156                                 krb4encpwd_printsub },
 157 #endif
 158 #ifdef  RSA_ENCPWD
 159         { AUTHTYPE_RSA_ENCPWD, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
 160                                 rsaencpwd_init,
 161                                 rsaencpwd_send,
 162                                 rsaencpwd_is,
 163                                 rsaencpwd_reply,
 164                                 rsaencpwd_status,
 165                                 rsaencpwd_printsub },
 166 #endif
 167 #ifdef SRA
 168         { AUTHTYPE_SRA, AUTH_WHO_CLIENT|AUTH_HOW_ONE_WAY,
 169                                 sra_init,
 170                                 sra_send,
 171                                 sra_is,
 172                                 sra_reply,
 173                                 sra_status,
 174                                 sra_printsub },
 175
 176 #endif
 177         { 0, 0, 0, 0, 0, 0, 0, 0 },
 178 };
 179
 180 static Authenticator NoAuth = { 0, 0, 0, 0, 0, 0, 0, 0 };
 181
 182 static int      i_support = 0;
 183 static int      i_wont_support = 0;
 184
 185 Authenticator *
 186 findauthenticator(int type, int way)
 187 {
 188         Authenticator *ap = authenticators;
 189
 190         while (ap->type && (ap->type != type || ap->way != way))
 191                 ++ap;
 192         return(ap->type ? ap : 0);
 193 }
 194
 195 void
 196 auth_init(const char *name, int server)
 197 {
 198         Authenticator *ap = authenticators;
 199
 200         Server = server;
 201         Name = name;
 202
 203         i_support = 0;
 204         authenticated = NULL;
 205         authenticating = 0;
 206         while (ap->type) {
 207                 if (!ap->init || (*ap->init)(ap, server)) {
 208                         i_support |= typemask(ap->type);
 209                         if (auth_debug_mode)
 210                                 printf(">>>%s: I support auth type %d %d\r\n",
 211                                         Name,
 212                                         ap->type, ap->way);
 213                 }
 214                 else if (auth_debug_mode)
 215                         printf(">>>%s: Init failed: auth type %d %d\r\n",
 216                                 Name, ap->type, ap->way);
 217                 ++ap;
 218         }
 219 }
 220
 221 void
 222 auth_disable_name(char *name)
 223 {
 224         int x;
 225         for (x = 0; x < AUTHTYPE_CNT; ++x) {
 226                 if (AUTHTYPE_NAME(x) && !strcasecmp(name, AUTHTYPE_NAME(x))) {
 227                         i_wont_support |= typemask(x);
 228                         break;
 229                 }
 230         }
 231 }
 232
 233 int
 234 getauthmask(char *type, int *maskp)
 235 {
 236         int x;
 237
 238         if (AUTHTYPE_NAME(0) && !strcasecmp(type, AUTHTYPE_NAME(0))) {
 239                 *maskp = -1;
 240                 return(1);
 241         }
 242
 243         for (x = 1; x < AUTHTYPE_CNT; ++x) {
 244                 if (AUTHTYPE_NAME(x) && !strcasecmp(type, AUTHTYPE_NAME(x))) {
 245                         *maskp = typemask(x);
 246                         return(1);
 247                 }
 248         }
 249         return(0);
 250 }
 251
 252 int
 253 auth_enable(char *type)
 254 {
 255         return(auth_onoff(type, 1));
 256 }
 257
 258 int
 259 auth_disable(char *type)
 260 {
 261         return(auth_onoff(type, 0));
 262 }
 263
 264 int
 265 auth_onoff(char *type, int on)
 266 {
 267         int i, mask = -1;
 268         Authenticator *ap;
 269
 270         if (!strcasecmp(type, "?") || !strcasecmp(type, "help")) {
 271                 printf("auth %s 'type'\n", on ? "enable" : "disable");
 272                 printf("Where 'type' is one of:\n");
 273                 printf("\t%s\n", AUTHTYPE_NAME(0));
 274                 mask = 0;
 275                 for (ap = authenticators; ap->type; ap++) {
 276                         if ((mask & (i = typemask(ap->type))) != 0)
 277                                 continue;
 278                         mask |= i;
 279                         printf("\t%s\n", AUTHTYPE_NAME(ap->type));
 280                 }
 281                 return(0);
 282         }
 283
 284         if (!getauthmask(type, &mask)) {
 285                 printf("%s: invalid authentication type\n", type);
 286                 return(0);
 287         }
 288         if (on)
 289                 i_wont_support &= ~mask;
 290         else
 291                 i_wont_support |= mask;
 292         return(1);
 293 }
 294
 295 int
 296 auth_togdebug(int on)
 297 {
 298         if (on < 0)
 299                 auth_debug_mode ^= 1;
 300         else
 301                 auth_debug_mode = on;
 302         printf("auth debugging %s\n", auth_debug_mode ? "enabled" : "disabled");
 303         return(1);
 304 }
 305
 306 int
 307 auth_status(void)
 308 {
 309         Authenticator *ap;
 310         int i, mask;
 311
 312         if (i_wont_support == -1)
 313                 printf("Authentication disabled\n");
 314         else
 315                 printf("Authentication enabled\n");
 316
 317         mask = 0;
 318         for (ap = authenticators; ap->type; ap++) {
 319                 if ((mask & (i = typemask(ap->type))) != 0)
 320                         continue;
 321                 mask |= i;
 322                 printf("%s: %s\n", AUTHTYPE_NAME(ap->type),
 323                         (i_wont_support & typemask(ap->type)) ?
 324                                         "disabled" : "enabled");
 325         }
 326         return(1);
 327 }
 328
 329 /*
 330  * This routine is called by the server to start authentication
 331  * negotiation.
 332  */
 333 void
 334 auth_request(void)
 335 {
 336         static unsigned char str_request[64] = { IAC, SB,
 337                                                  TELOPT_AUTHENTICATION,
 338                                                  TELQUAL_SEND, };
 339         Authenticator *ap = authenticators;
 340         unsigned char *e = str_request + 4;
 341
 342         if (!authenticating) {
 343                 authenticating = 1;
 344                 while (ap->type) {
 345                         if (i_support & ~i_wont_support & typemask(ap->type)) {
 346                                 if (auth_debug_mode) {
 347                                         printf(">>>%s: Sending type %d %d\r\n",
 348                                                 Name, ap->type, ap->way);
 349                                 }
 350                                 *e++ = ap->type;
 351                                 *e++ = ap->way;
 352                         }
 353                         ++ap;
 354                 }
 355                 *e++ = IAC;
 356                 *e++ = SE;
 357                 net_write(str_request, e - str_request);
 358                 printsub('>', &str_request[2], e - str_request - 2);
 359         }
 360 }
 361
 362 /*
 363  * This is called when an AUTH SEND is received.
 364  * It should never arrive on the server side (as only the server can
 365  * send an AUTH SEND).
 366  * You should probably respond to it if you can...
 367  *
 368  * If you want to respond to the types out of order (i.e. even
 369  * if he sends  LOGIN KERBEROS and you support both, you respond
 370  * with KERBEROS instead of LOGIN (which is against what the
 371  * protocol says)) you will have to hack this code...
 372  */
 373 void
 374 auth_send(unsigned char *data, int cnt)
 375 {
 376         Authenticator *ap;
 377         static unsigned char str_none[] = { IAC, SB, TELOPT_AUTHENTICATION,
 378                                             TELQUAL_IS, AUTHTYPE_NULL, 0,
 379                                             IAC, SE };
 380         if (Server) {
 381                 if (auth_debug_mode) {
 382                         printf(">>>%s: auth_send called!\r\n", Name);
 383                 }
 384                 return;
 385         }
 386
 387         if (auth_debug_mode) {
 388                 printf(">>>%s: auth_send got:", Name);
 389                 printd(data, cnt); printf("\r\n");
 390         }
 391
 392         /*
 393          * Save the data, if it is new, so that we can continue looking
 394          * at it if the authorization we try doesn't work
 395          */
 396         if (data < _auth_send_data ||
 397             data > _auth_send_data + sizeof(_auth_send_data)) {
 398                 auth_send_cnt = (size_t)cnt > sizeof(_auth_send_data)
 399                                         ? sizeof(_auth_send_data)
 400                                         : cnt;
 401                 memmove((void *)_auth_send_data, (void *)data, auth_send_cnt);
 402                 auth_send_data = _auth_send_data;
 403         } else {
 404                 /*
 405                  * This is probably a no-op, but we just make sure
 406                  */
 407                 auth_send_data = data;
 408                 auth_send_cnt = cnt;
 409         }
 410         while ((auth_send_cnt -= 2) >= 0) {
 411                 if (auth_debug_mode)
 412                         printf(">>>%s: He supports %d\r\n",
 413                                 Name, *auth_send_data);
 414                 if ((i_support & ~i_wont_support) & typemask(*auth_send_data)) {
 415                         ap = findauthenticator(auth_send_data[0],
 416                                                auth_send_data[1]);
 417                         if (ap && ap->send) {
 418                                 if (auth_debug_mode)
 419                                         printf(">>>%s: Trying %d %d\r\n",
 420                                                 Name, auth_send_data[0],
 421                                                         auth_send_data[1]);
 422                                 if ((*ap->send)(ap)) {
 423                                         /*
 424                                          * Okay, we found one we like
 425                                          * and did it.
 426                                          * we can go home now.
 427                                          */
 428                                         if (auth_debug_mode)
 429                                                 printf(">>>%s: Using type %d\r\n",
 430                                                         Name, *auth_send_data);
 431                                         auth_send_data += 2;
 432                                         return;
 433                                 }
 434                         }
 435                         /* else
 436                          *      just continue on and look for the
 437                          *      next one if we didn't do anything.
 438                          */
 439                 }
 440                 auth_send_data += 2;
 441         }
 442         net_write(str_none, sizeof(str_none));
 443         printsub('>', &str_none[2], sizeof(str_none) - 2);
 444         if (auth_debug_mode)
 445                 printf(">>>%s: Sent failure message\r\n", Name);
 446         auth_finished(0, AUTH_REJECT);
 447 }
 448
 449 void
 450 auth_send_retry(void)
 451 {
 452         /*
 453          * if auth_send_cnt <= 0 then auth_send will end up rejecting
 454          * the authentication and informing the other side of this.
 455          */
 456         auth_send(auth_send_data, auth_send_cnt);
 457 }
 458
 459 void
 460 auth_is(unsigned char *data, int cnt)
 461 {
 462         Authenticator *ap;
 463
 464         if (cnt < 2)
 465                 return;
 466
 467         if (data[0] == AUTHTYPE_NULL) {
 468                 auth_finished(0, AUTH_REJECT);
 469                 return;
 470         }
 471
 472         if ((ap = findauthenticator(data[0], data[1]))) {
 473                 if (ap->is)
 474                         (*ap->is)(ap, data+2, cnt-2);
 475         } else if (auth_debug_mode)
 476                 printf(">>>%s: Invalid authentication in IS: %d\r\n",
 477                         Name, *data);
 478 }
 479
 480 void
 481 auth_reply(unsigned char *data, int cnt)
 482 {
 483         Authenticator *ap;
 484
 485         if (cnt < 2)
 486                 return;
 487
 488         if ((ap = findauthenticator(data[0], data[1]))) {
 489                 if (ap->reply)
 490                         (*ap->reply)(ap, data+2, cnt-2);
 491         } else if (auth_debug_mode)
 492                 printf(">>>%s: Invalid authentication in SEND: %d\r\n",
 493                         Name, *data);
 494 }
 495
 496 void
 497 auth_name(unsigned char *data, int cnt)
 498 {
 499         unsigned char savename[256];
 500
 501         if (cnt < 1) {
 502                 if (auth_debug_mode)
 503                         printf(">>>%s: Empty name in NAME\r\n", Name);
 504                 return;
 505         }
 506         if ((size_t)cnt > sizeof(savename) - 1) {
 507                 if (auth_debug_mode)
 508                         printf(">>>%s: Name in NAME (%d) exceeds %d length\r\n",
 509                                         Name, cnt, (u_int)sizeof(savename)-1);
 510                 return;
 511         }
 512         memmove((void *)savename, (void *)data, cnt);
 513         savename[cnt] = '\0';   /* Null terminate */
 514         if (auth_debug_mode)
 515                 printf(">>>%s: Got NAME [%s]\r\n", Name, savename);
 516         auth_encrypt_user(savename);
 517 }
 518
 519 int
 520 auth_sendname(unsigned char *cp, int len)
 521 {
 522         static unsigned char str_request[256+6]
 523                         = { IAC, SB, TELOPT_AUTHENTICATION, TELQUAL_NAME, };
 524         unsigned char *e = str_request + 4;
 525         unsigned char *ee = &str_request[sizeof(str_request)-2];
 526
 527         while (--len >= 0) {
 528                 if ((*e++ = *cp++) == IAC)
 529                         *e++ = IAC;
 530                 if (e >= ee)
 531                         return(0);
 532         }
 533         *e++ = IAC;
 534         *e++ = SE;
 535         net_write(str_request, e - str_request);
 536         printsub('>', &str_request[2], e - &str_request[2]);
 537         return(1);
 538 }
 539
 540 void
 541 auth_finished(Authenticator *ap, int result)
 542 {
 543         if (!(authenticated = ap))
 544                 authenticated = &NoAuth;
 545         validuser = result;
 546 }
 547
 548 /* ARGSUSED */
 549 static void
 550 auth_intr(int sig __unused)
 551 {
 552         auth_finished(0, AUTH_REJECT);
 553 }
 554
 555 int
 556 auth_wait(char *name)
 557 {
 558         if (auth_debug_mode)
 559                 printf(">>>%s: in auth_wait.\r\n", Name);
 560
 561         if (Server && !authenticating)
 562                 return(0);
 563
 564         (void) signal(SIGALRM, auth_intr);
 565         alarm(30);
 566         while (!authenticated)
 567                 if (telnet_spin())
 568                         break;
 569         alarm(0);
 570         (void) signal(SIGALRM, SIG_DFL);
 571
 572         /*
 573          * Now check to see if the user is valid or not
 574          */
 575         if (!authenticated || authenticated == &NoAuth)
 576                 return(AUTH_REJECT);
 577
 578         if (validuser == AUTH_VALID)
 579                 validuser = AUTH_USER;
 580
 581         if (authenticated->status)
 582                 validuser = (*authenticated->status)(authenticated,
 583                                                      name, validuser);
 584         return(validuser);
 585 }
 586
 587 void
 588 auth_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
 589 {
 590         Authenticator *ap;
 591
 592         if ((ap = findauthenticator(data[1], data[2])) && ap->printsub)
 593                 (*ap->printsub)(data, cnt, buf, buflen);
 594         else
 595                 auth_gen_printsub(data, cnt, buf, buflen);
 596 }
 597
 598 void
 599 auth_gen_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
 600 {
 601         unsigned char *cp;
 602         unsigned char tbuf[16];
 603
 604         cnt -= 3;
 605         data += 3;
 606         buf[buflen-1] = '\0';
 607         buf[buflen-2] = '*';
 608         buflen -= 2;
 609         for (; cnt > 0; cnt--, data++) {
 610                 sprintf((char *)tbuf, " %d", *data);
 611                 for (cp = tbuf; *cp && buflen > 0; --buflen)
 612                         *buf++ = *cp++;
 613                 if (buflen <= 0)
 614                         return;
 615         }
 616         *buf = '\0';
 617 }
 618 #endif