src/libs/libtelnet/encrypt.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
  34 #include <sys/cdefs.h>
  35
  36 __FBSDID("$FreeBSD: src/contrib/telnet/libtelnet/encrypt.c,v 1.9 2002/06/26 17:06:14 markm Exp $");
  37
  38 #ifndef lint
  39 #if 0
  40 static const char sccsid[] = "@(#)encrypt.c     8.2 (Berkeley) 5/30/95";
  41 #endif
  42 #endif /* not lint */
  43
  44 /*
  45  * Copyright (C) 1990 by the Massachusetts Institute of Technology
  46  *
  47  * Export of this software from the United States of America is assumed
  48  * to require a specific license from the United States Government.
  49  * It is the responsibility of any person or organization contemplating
  50  * export to obtain such a license before exporting.
  51  *
  52  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
  53  * distribute this software and its documentation for any purpose and
  54  * without fee is hereby granted, provided that the above copyright
  55  * notice appear in all copies and that both that copyright notice and
  56  * this permission notice appear in supporting documentation, and that
  57  * the name of M.I.T. not be used in advertising or publicity pertaining
  58  * to distribution of the software without specific, written prior
  59  * permission.  M.I.T. makes no representations about the suitability of
  60  * this software for any purpose.  It is provided "as is" without express
  61  * or implied warranty.
  62  */
  63
  64 #ifdef  ENCRYPTION
  65
  66 #include <sys/types.h>
  67 #define ENCRYPT_NAMES
  68 #include <arpa/telnet.h>
  69 #include <stdio.h>
  70 #include <stdlib.h>
  71 #include <string.h>
  72
  73 #include "encrypt.h"
  74 #include "misc.h"
  75
  76 /*
  77  * These functions pointers point to the current routines
  78  * for encrypting and decrypting data.
  79  */
  80 void    (*encrypt_output)(unsigned char *, int);
  81 int     (*decrypt_input)(int);
  82
  83 int EncryptType(char *type, char *mode);
  84 int EncryptStart(char *mode);
  85 int EncryptStop(char *mode);
  86 int EncryptStartInput(void);
  87 int EncryptStartOutput(void);
  88 int EncryptStopInput(void);
  89 int EncryptStopOutput(void);
  90
  91 int encrypt_debug_mode = 0;
  92 static int decrypt_mode = 0;
  93 static int encrypt_mode = 0;
  94 static int encrypt_verbose = 0;
  95 static int autoencrypt = 0;
  96 static int autodecrypt = 0;
  97 static int havesessionkey = 0;
  98 static int Server = 0;
  99 static const char *Name = "Noname";
 100
 101 #define typemask(x)     ((x) > 0 ? 1 << ((x)-1) : 0)
 102
 103 static u_long i_support_encrypt = 0
 104  | typemask(ENCTYPE_DES_CFB64) | typemask(ENCTYPE_DES_OFB64)
 105  |0;
 106 static u_long i_support_decrypt = 0
 107  | typemask(ENCTYPE_DES_CFB64) | typemask(ENCTYPE_DES_OFB64)
 108  |0;
 109
 110 static u_long i_wont_support_encrypt = 0;
 111 static u_long i_wont_support_decrypt = 0;
 112 #define I_SUPPORT_ENCRYPT       (i_support_encrypt & ~i_wont_support_encrypt)
 113 #define I_SUPPORT_DECRYPT       (i_support_decrypt & ~i_wont_support_decrypt)
 114
 115 static u_long remote_supports_encrypt = 0;
 116 static u_long remote_supports_decrypt = 0;
 117
 118 static Encryptions encryptions[] = {
 119     { "DES_CFB64",      ENCTYPE_DES_CFB64,
 120                         cfb64_encrypt,
 121                         cfb64_decrypt,
 122                         cfb64_init,
 123                         cfb64_start,
 124                         cfb64_is,
 125                         cfb64_reply,
 126                         cfb64_session,
 127                         cfb64_keyid,
 128                         cfb64_printsub },
 129     { "DES_OFB64",      ENCTYPE_DES_OFB64,
 130                         ofb64_encrypt,
 131                         ofb64_decrypt,
 132                         ofb64_init,
 133                         ofb64_start,
 134                         ofb64_is,
 135                         ofb64_reply,
 136                         ofb64_session,
 137                         ofb64_keyid,
 138                         ofb64_printsub },
 139     { NULL, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
 140 };
 141
 142 static unsigned char str_send[64] = { IAC, SB, TELOPT_ENCRYPT,
 143                                          ENCRYPT_SUPPORT };
 144 static unsigned char str_suplen = 0;
 145 static unsigned char str_start[72] = { IAC, SB, TELOPT_ENCRYPT };
 146 static unsigned char str_end[] = { IAC, SB, TELOPT_ENCRYPT, 0, IAC, SE };
 147
 148 Encryptions *
 149 findencryption(int type)
 150 {
 151         Encryptions *ep = encryptions;
 152
 153         if (!(I_SUPPORT_ENCRYPT & remote_supports_decrypt & (unsigned)typemask(type)))
 154                 return(0);
 155         while (ep->type && ep->type != type)
 156                 ++ep;
 157         return(ep->type ? ep : 0);
 158 }
 159
 160 static Encryptions *
 161 finddecryption(int type)
 162 {
 163         Encryptions *ep = encryptions;
 164
 165         if (!(I_SUPPORT_DECRYPT & remote_supports_encrypt & (unsigned)typemask(type)))
 166                 return(0);
 167         while (ep->type && ep->type != type)
 168                 ++ep;
 169         return(ep->type ? ep : 0);
 170 }
 171
 172 #define MAXKEYLEN 64
 173
 174 static struct key_info {
 175         unsigned char keyid[MAXKEYLEN];
 176         int keylen;
 177         int dir;
 178         int *modep;
 179         Encryptions *(*getcrypt)(int);
 180 } ki[2] = {
 181         { { 0 }, 0, DIR_ENCRYPT, &encrypt_mode, findencryption },
 182         { { 0 }, 0, DIR_DECRYPT, &decrypt_mode, finddecryption },
 183 };
 184
 185 static void encrypt_keyid(struct key_info *kp, unsigned char *keyid, int len);
 186
 187 void
 188 encrypt_init(const char *name, int server)
 189 {
 190         Encryptions *ep = encryptions;
 191
 192         Name = name;
 193         Server = server;
 194         i_support_encrypt = i_support_decrypt = 0;
 195         remote_supports_encrypt = remote_supports_decrypt = 0;
 196         encrypt_mode = 0;
 197         decrypt_mode = 0;
 198         encrypt_output = 0;
 199         decrypt_input = 0;
 200
 201         str_suplen = 4;
 202
 203         while (ep->type) {
 204                 if (encrypt_debug_mode)
 205                         printf(">>>%s: I will support %s\r\n",
 206                                 Name, ENCTYPE_NAME(ep->type));
 207                 i_support_encrypt |= typemask(ep->type);
 208                 i_support_decrypt |= typemask(ep->type);
 209                 if ((i_wont_support_decrypt & typemask(ep->type)) == 0)
 210                         if ((str_send[str_suplen++] = ep->type) == IAC)
 211                                 str_send[str_suplen++] = IAC;
 212                 if (ep->init)
 213                         (*ep->init)(Server);
 214                 ++ep;
 215         }
 216         str_send[str_suplen++] = IAC;
 217         str_send[str_suplen++] = SE;
 218 }
 219
 220 static void
 221 encrypt_list_types(void)
 222 {
 223         Encryptions *ep = encryptions;
 224
 225         printf("Valid encryption types:\n");
 226         while (ep->type) {
 227                 printf("\t%s (%d)\r\n", ENCTYPE_NAME(ep->type), ep->type);
 228                 ++ep;
 229         }
 230 }
 231
 232 int
 233 EncryptEnable(char *type, char *mode)
 234 {
 235         if (isprefix(type, "help") || isprefix(type, "?")) {
 236                 printf("Usage: encrypt enable <type> [input|output]\n");
 237                 encrypt_list_types();
 238                 return(0);
 239         }
 240         if (EncryptType(type, mode))
 241                 return(EncryptStart(mode));
 242         return(0);
 243 }
 244
 245 int
 246 EncryptDisable(char *type, char *mode)
 247 {
 248         Encryptions *ep;
 249         int ret = 0;
 250
 251         if (isprefix(type, "help") || isprefix(type, "?")) {
 252                 printf("Usage: encrypt disable <type> [input|output]\n");
 253                 encrypt_list_types();
 254         } else if ((ep = (Encryptions *)genget(type, (char **)encryptions,
 255                                                 sizeof(Encryptions))) == 0) {
 256                 printf("%s: invalid encryption type\n", type);
 257         } else if (Ambiguous((char **)ep)) {
 258                 printf("Ambiguous type '%s'\n", type);
 259         } else {
 260                 if ((mode == 0) || (isprefix(mode, "input") ? 1 : 0)) {
 261                         if (decrypt_mode == ep->type)
 262                                 EncryptStopInput();
 263                         i_wont_support_decrypt |= typemask(ep->type);
 264                         ret = 1;
 265                 }
 266                 if ((mode == 0) || (isprefix(mode, "output"))) {
 267                         if (encrypt_mode == ep->type)
 268                                 EncryptStopOutput();
 269                         i_wont_support_encrypt |= typemask(ep->type);
 270                         ret = 1;
 271                 }
 272                 if (ret == 0)
 273                         printf("%s: invalid encryption mode\n", mode);
 274         }
 275         return(ret);
 276 }
 277
 278 int
 279 EncryptType(char *type, char *mode)
 280 {
 281         Encryptions *ep;
 282         int ret = 0;
 283
 284         if (isprefix(type, "help") || isprefix(type, "?")) {
 285                 printf("Usage: encrypt type <type> [input|output]\n");
 286                 encrypt_list_types();
 287         } else if ((ep = (Encryptions *)genget(type, (char **)encryptions,
 288                                                 sizeof(Encryptions))) == 0) {
 289                 printf("%s: invalid encryption type\n", type);
 290         } else if (Ambiguous((char **)ep)) {
 291                 printf("Ambiguous type '%s'\n", type);
 292         } else {
 293                 if ((mode == 0) || isprefix(mode, "input")) {
 294                         decrypt_mode = ep->type;
 295                         i_wont_support_decrypt &= ~typemask(ep->type);
 296                         ret = 1;
 297                 }
 298                 if ((mode == 0) || isprefix(mode, "output")) {
 299                         encrypt_mode = ep->type;
 300                         i_wont_support_encrypt &= ~typemask(ep->type);
 301                         ret = 1;
 302                 }
 303                 if (ret == 0)
 304                         printf("%s: invalid encryption mode\n", mode);
 305         }
 306         return(ret);
 307 }
 308
 309 int
 310 EncryptStart(char *mode)
 311 {
 312         int ret = 0;
 313         if (mode) {
 314                 if (isprefix(mode, "input"))
 315                         return(EncryptStartInput());
 316                 if (isprefix(mode, "output"))
 317                         return(EncryptStartOutput());
 318                 if (isprefix(mode, "help") || isprefix(mode, "?")) {
 319                         printf("Usage: encrypt start [input|output]\n");
 320                         return(0);
 321                 }
 322                 printf("%s: invalid encryption mode 'encrypt start ?' for help\n", mode);
 323                 return(0);
 324         }
 325         ret += EncryptStartInput();
 326         ret += EncryptStartOutput();
 327         return(ret);
 328 }
 329
 330 int
 331 EncryptStartInput(void)
 332 {
 333         if (decrypt_mode) {
 334                 encrypt_send_request_start();
 335                 return(1);
 336         }
 337         printf("No previous decryption mode, decryption not enabled\r\n");
 338         return(0);
 339 }
 340
 341 int
 342 EncryptStartOutput(void)
 343 {
 344         if (encrypt_mode) {
 345                 encrypt_start_output(encrypt_mode);
 346                 return(1);
 347         }
 348         printf("No previous encryption mode, encryption not enabled\r\n");
 349         return(0);
 350 }
 351
 352 int
 353 EncryptStop(char *mode)
 354 {
 355         int ret = 0;
 356         if (mode) {
 357                 if (isprefix(mode, "input"))
 358                         return(EncryptStopInput());
 359                 if (isprefix(mode, "output"))
 360                         return(EncryptStopOutput());
 361                 if (isprefix(mode, "help") || isprefix(mode, "?")) {
 362                         printf("Usage: encrypt stop [input|output]\n");
 363                         return(0);
 364                 }
 365                 printf("%s: invalid encryption mode 'encrypt stop ?' for help\n", mode);
 366                 return(0);
 367         }
 368         ret += EncryptStopInput();
 369         ret += EncryptStopOutput();
 370         return(ret);
 371 }
 372
 373 int
 374 EncryptStopInput(void)
 375 {
 376         encrypt_send_request_end();
 377         return(1);
 378 }
 379
 380 int
 381 EncryptStopOutput(void)
 382 {
 383         encrypt_send_end();
 384         return(1);
 385 }
 386
 387 void
 388 encrypt_display(void)
 389 {
 390         if (encrypt_output)
 391                 printf("Currently encrypting output with %s\r\n",
 392                         ENCTYPE_NAME(encrypt_mode));
 393         if (decrypt_input)
 394                 printf("Currently decrypting input with %s\r\n",
 395                         ENCTYPE_NAME(decrypt_mode));
 396 }
 397
 398 int
 399 EncryptStatus(void)
 400 {
 401         if (encrypt_output)
 402                 printf("Currently encrypting output with %s\r\n",
 403                         ENCTYPE_NAME(encrypt_mode));
 404         else if (encrypt_mode) {
 405                 printf("Currently output is clear text.\r\n");
 406                 printf("Last encryption mode was %s\r\n",
 407                         ENCTYPE_NAME(encrypt_mode));
 408         }
 409         if (decrypt_input) {
 410                 printf("Currently decrypting input with %s\r\n",
 411                         ENCTYPE_NAME(decrypt_mode));
 412         } else if (decrypt_mode) {
 413                 printf("Currently input is clear text.\r\n");
 414                 printf("Last decryption mode was %s\r\n",
 415                         ENCTYPE_NAME(decrypt_mode));
 416         }
 417         return 1;
 418 }
 419
 420 void
 421 encrypt_send_support(void)
 422 {
 423         if (str_suplen) {
 424                 /*
 425                  * If the user has requested that decryption start
 426                  * immediatly, then send a "REQUEST START" before
 427                  * we negotiate the type.
 428                  */
 429                 if (!Server && autodecrypt)
 430                         encrypt_send_request_start();
 431                 net_write(str_send, str_suplen);
 432                 printsub('>', &str_send[2], str_suplen - 2);
 433                 str_suplen = 0;
 434         }
 435 }
 436
 437 int
 438 EncryptDebug(int on)
 439 {
 440         if (on < 0)
 441                 encrypt_debug_mode ^= 1;
 442         else
 443                 encrypt_debug_mode = on;
 444         printf("Encryption debugging %s\r\n",
 445                 encrypt_debug_mode ? "enabled" : "disabled");
 446         return(1);
 447 }
 448
 449 int
 450 EncryptVerbose(int on)
 451 {
 452         if (on < 0)
 453                 encrypt_verbose ^= 1;
 454         else
 455                 encrypt_verbose = on;
 456         printf("Encryption %s verbose\r\n",
 457                 encrypt_verbose ? "is" : "is not");
 458         return(1);
 459 }
 460
 461 int
 462 EncryptAutoEnc(int on)
 463 {
 464         encrypt_auto(on);
 465         printf("Automatic encryption of output is %s\r\n",
 466                 autoencrypt ? "enabled" : "disabled");
 467         return(1);
 468 }
 469
 470 int
 471 EncryptAutoDec(int on)
 472 {
 473         decrypt_auto(on);
 474         printf("Automatic decryption of input is %s\r\n",
 475                 autodecrypt ? "enabled" : "disabled");
 476         return(1);
 477 }
 478
 479 /*
 480  * Called when ENCRYPT SUPPORT is received.
 481  */
 482 void
 483 encrypt_support(unsigned char *typelist, int cnt)
 484 {
 485         int type, use_type = 0;
 486         Encryptions *ep;
 487
 488         /*
 489          * Forget anything the other side has previously told us.
 490          */
 491         remote_supports_decrypt = 0;
 492
 493         while (cnt-- > 0) {
 494                 type = *typelist++;
 495                 if (encrypt_debug_mode)
 496                         printf(">>>%s: He is supporting %s (%d)\r\n",
 497                                 Name,
 498                                 ENCTYPE_NAME(type), type);
 499                 if ((type < ENCTYPE_CNT) &&
 500                     (I_SUPPORT_ENCRYPT & typemask(type))) {
 501                         remote_supports_decrypt |= typemask(type);
 502                         if (use_type == 0)
 503                                 use_type = type;
 504                 }
 505         }
 506         if (use_type) {
 507                 ep = findencryption(use_type);
 508                 if (!ep)
 509                         return;
 510                 type = ep->start ? (*ep->start)(DIR_ENCRYPT, Server) : 0;
 511                 if (encrypt_debug_mode)
 512                         printf(">>>%s: (*ep->start)() returned %d\r\n",
 513                                         Name, type);
 514                 if (type < 0)
 515                         return;
 516                 encrypt_mode = use_type;
 517                 if (type == 0)
 518                         encrypt_start_output(use_type);
 519         }
 520 }
 521
 522 void
 523 encrypt_is(unsigned char *data, int cnt)
 524 {
 525         Encryptions *ep;
 526         int type, ret;
 527
 528         if (--cnt < 0)
 529                 return;
 530         type = *data++;
 531         if (type < ENCTYPE_CNT)
 532                 remote_supports_encrypt |= typemask(type);
 533         if (!(ep = finddecryption(type))) {
 534                 if (encrypt_debug_mode)
 535                         printf(">>>%s: Can't find type %s (%d) for initial negotiation\r\n",
 536                                 Name,
 537                                 ENCTYPE_NAME_OK(type)
 538                                         ? ENCTYPE_NAME(type) : "(unknown)",
 539                                 type);
 540                 return;
 541         }
 542         if (!ep->is) {
 543                 if (encrypt_debug_mode)
 544                         printf(">>>%s: No initial negotiation needed for type %s (%d)\r\n",
 545                                 Name,
 546                                 ENCTYPE_NAME_OK(type)
 547                                         ? ENCTYPE_NAME(type) : "(unknown)",
 548                                 type);
 549                 ret = 0;
 550         } else {
 551                 ret = (*ep->is)(data, cnt);
 552                 if (encrypt_debug_mode)
 553                         printf("(*ep->is)(%p, %d) returned %s(%d)\n", data, cnt,
 554                                 (ret < 0) ? "FAIL " :
 555                                 (ret == 0) ? "SUCCESS " : "MORE_TO_DO ", ret);
 556         }
 557         if (ret < 0) {
 558                 autodecrypt = 0;
 559         } else {
 560                 decrypt_mode = type;
 561                 if (ret == 0 && autodecrypt)
 562                         encrypt_send_request_start();
 563         }
 564 }
 565
 566 void
 567 encrypt_reply(unsigned char *data, int cnt)
 568 {
 569         Encryptions *ep;
 570         int ret, type;
 571
 572         if (--cnt < 0)
 573                 return;
 574         type = *data++;
 575         if (!(ep = findencryption(type))) {
 576                 if (encrypt_debug_mode)
 577                         printf(">>>%s: Can't find type %s (%d) for initial negotiation\r\n",
 578                                 Name,
 579                                 ENCTYPE_NAME_OK(type)
 580                                         ? ENCTYPE_NAME(type) : "(unknown)",
 581                                 type);
 582                 return;
 583         }
 584         if (!ep->reply) {
 585                 if (encrypt_debug_mode)
 586                         printf(">>>%s: No initial negotiation needed for type %s (%d)\r\n",
 587                                 Name,
 588                                 ENCTYPE_NAME_OK(type)
 589                                         ? ENCTYPE_NAME(type) : "(unknown)",
 590                                 type);
 591                 ret = 0;
 592         } else {
 593                 ret = (*ep->reply)(data, cnt);
 594                 if (encrypt_debug_mode)
 595                         printf("(*ep->reply)(%p, %d) returned %s(%d)\n",
 596                                 data, cnt,
 597                                 (ret < 0) ? "FAIL " :
 598                                 (ret == 0) ? "SUCCESS " : "MORE_TO_DO ", ret);
 599         }
 600         if (encrypt_debug_mode)
 601                 printf(">>>%s: encrypt_reply returned %d\n", Name, ret);
 602         if (ret < 0) {
 603                 autoencrypt = 0;
 604         } else {
 605                 encrypt_mode = type;
 606                 if (ret == 0 && autoencrypt)
 607                         encrypt_start_output(type);
 608         }
 609 }
 610
 611 /*
 612  * Called when a ENCRYPT START command is received.
 613  */
 614 void
 615 encrypt_start(unsigned char *data __unused, int cnt __unused)
 616 {
 617         Encryptions *ep;
 618
 619         if (!decrypt_mode) {
 620                 /*
 621                  * Something is wrong.  We should not get a START
 622                  * command without having already picked our
 623                  * decryption scheme.  Send a REQUEST-END to
 624                  * attempt to clear the channel...
 625                  */
 626                 printf("%s: Warning, Cannot decrypt input stream!!!\r\n", Name);
 627                 encrypt_send_request_end();
 628                 return;
 629         }
 630
 631         if ((ep = finddecryption(decrypt_mode))) {
 632                 decrypt_input = ep->input;
 633                 if (encrypt_verbose)
 634                         printf("[ Input is now decrypted with type %s ]\r\n",
 635                                 ENCTYPE_NAME(decrypt_mode));
 636                 if (encrypt_debug_mode)
 637                         printf(">>>%s: Start to decrypt input with type %s\r\n",
 638                                 Name, ENCTYPE_NAME(decrypt_mode));
 639         } else {
 640                 printf("%s: Warning, Cannot decrypt type %s (%d)!!!\r\n",
 641                                 Name,
 642                                 ENCTYPE_NAME_OK(decrypt_mode)
 643                                         ? ENCTYPE_NAME(decrypt_mode)
 644                                         : "(unknown)",
 645                                 decrypt_mode);
 646                 encrypt_send_request_end();
 647         }
 648 }
 649
 650 void
 651 encrypt_session_key( Session_Key *key, int server)
 652 {
 653         Encryptions *ep = encryptions;
 654
 655         havesessionkey = 1;
 656
 657         while (ep->type) {
 658                 if (ep->session)
 659                         (*ep->session)(key, server);
 660                 ++ep;
 661         }
 662 }
 663
 664 /*
 665  * Called when ENCRYPT END is received.
 666  */
 667 void
 668 encrypt_end(void)
 669 {
 670         decrypt_input = 0;
 671         if (encrypt_debug_mode)
 672                 printf(">>>%s: Input is back to clear text\r\n", Name);
 673         if (encrypt_verbose)
 674                 printf("[ Input is now clear text ]\r\n");
 675 }
 676
 677 /*
 678  * Called when ENCRYPT REQUEST-END is received.
 679  */
 680 void
 681 encrypt_request_end(void)
 682 {
 683         encrypt_send_end();
 684 }
 685
 686 /*
 687  * Called when ENCRYPT REQUEST-START is received.  If we receive
 688  * this before a type is picked, then that indicates that the
 689  * other side wants us to start encrypting data as soon as we
 690  * can.
 691  */
 692 void
 693 encrypt_request_start(unsigned char *data __unused, int cnt __unused)
 694 {
 695         if (encrypt_mode == 0)  {
 696                 if (Server)
 697                         autoencrypt = 1;
 698                 return;
 699         }
 700         encrypt_start_output(encrypt_mode);
 701 }
 702
 703 static unsigned char str_keyid[(MAXKEYLEN*2)+5] = { IAC, SB, TELOPT_ENCRYPT };
 704
 705 void
 706 encrypt_enc_keyid(unsigned char *keyid, int len)
 707 {
 708         encrypt_keyid(&ki[1], keyid, len);
 709 }
 710
 711 void
 712 encrypt_dec_keyid(unsigned char *keyid, int len)
 713 {
 714         encrypt_keyid(&ki[0], keyid, len);
 715 }
 716
 717 void
 718 encrypt_keyid(struct key_info *kp, unsigned char *keyid, int len)
 719 {
 720         Encryptions *ep;
 721         int dir = kp->dir;
 722         int ret = 0;
 723
 724         if (!(ep = (*kp->getcrypt)(*kp->modep))) {
 725                 if (len == 0)
 726                         return;
 727                 kp->keylen = 0;
 728         } else if (len == 0) {
 729                 /*
 730                  * Empty option, indicates a failure.
 731                  */
 732                 if (kp->keylen == 0)
 733                         return;
 734                 kp->keylen = 0;
 735                 if (ep->keyid)
 736                         (void)(*ep->keyid)(dir, kp->keyid, &kp->keylen);
 737
 738         } else if ((len != kp->keylen) ||
 739                    (memcmp(keyid, kp->keyid, len) != 0)) {
 740                 /*
 741                  * Length or contents are different
 742                  */
 743                 kp->keylen = len;
 744                 memmove(kp->keyid, keyid, len);
 745                 if (ep->keyid)
 746                         (void)(*ep->keyid)(dir, kp->keyid, &kp->keylen);
 747         } else {
 748                 if (ep->keyid)
 749                         ret = (*ep->keyid)(dir, kp->keyid, &kp->keylen);
 750                 if ((ret == 0) && (dir == DIR_ENCRYPT) && autoencrypt)
 751                         encrypt_start_output(*kp->modep);
 752                 return;
 753         }
 754
 755         encrypt_send_keyid(dir, kp->keyid, kp->keylen, 0);
 756 }
 757
 758 void
 759 encrypt_send_keyid(int dir, const char *keyid, int keylen, int saveit)
 760 {
 761         unsigned char *strp;
 762
 763         str_keyid[3] = (dir == DIR_ENCRYPT)
 764                         ? ENCRYPT_ENC_KEYID : ENCRYPT_DEC_KEYID;
 765         if (saveit) {
 766                 struct key_info *kp = &ki[(dir == DIR_ENCRYPT) ? 0 : 1];
 767                 memmove(kp->keyid, keyid, keylen);
 768                 kp->keylen = keylen;
 769         }
 770
 771         for (strp = &str_keyid[4]; keylen > 0; --keylen) {
 772                 if ((*strp++ = *keyid++) == IAC)
 773                         *strp++ = IAC;
 774         }
 775         *strp++ = IAC;
 776         *strp++ = SE;
 777         net_write(str_keyid, strp - str_keyid);
 778         printsub('>', &str_keyid[2], strp - str_keyid - 2);
 779 }
 780
 781 void
 782 encrypt_auto(int on)
 783 {
 784         if (on < 0)
 785                 autoencrypt ^= 1;
 786         else
 787                 autoencrypt = on ? 1 : 0;
 788 }
 789
 790 void
 791 decrypt_auto(int on)
 792 {
 793         if (on < 0)
 794                 autodecrypt ^= 1;
 795         else
 796                 autodecrypt = on ? 1 : 0;
 797 }
 798
 799 void
 800 encrypt_start_output(int type)
 801 {
 802         Encryptions *ep;
 803         unsigned char *p;
 804         int i;
 805
 806         if (!(ep = findencryption(type))) {
 807                 if (encrypt_debug_mode) {
 808                         printf(">>>%s: Can't encrypt with type %s (%d)\r\n",
 809                                 Name,
 810                                 ENCTYPE_NAME_OK(type)
 811                                         ? ENCTYPE_NAME(type) : "(unknown)",
 812                                 type);
 813                 }
 814                 return;
 815         }
 816         if (ep->start) {
 817                 i = (*ep->start)(DIR_ENCRYPT, Server);
 818                 if (encrypt_debug_mode) {
 819                         printf(">>>%s: Encrypt start: %s (%d) %s\r\n",
 820                                 Name,
 821                                 (i < 0) ? "failed" :
 822                                         "initial negotiation in progress",
 823                                 i, ENCTYPE_NAME(type));
 824                 }
 825                 if (i)
 826                         return;
 827         }
 828         p = str_start + 3;
 829         *p++ = ENCRYPT_START;
 830         for (i = 0; i < ki[0].keylen; ++i) {
 831                 if ((*p++ = ki[0].keyid[i]) == IAC)
 832                         *p++ = IAC;
 833         }
 834         *p++ = IAC;
 835         *p++ = SE;
 836         net_write(str_start, p - str_start);
 837         net_encrypt();
 838         printsub('>', &str_start[2], p - &str_start[2]);
 839         /*
 840          * If we are already encrypting in some mode, then
 841          * encrypt the ring (which includes our request) in
 842          * the old mode, mark it all as "clear text" and then
 843          * switch to the new mode.
 844          */
 845         encrypt_output = ep->output;
 846         encrypt_mode = type;
 847         if (encrypt_debug_mode)
 848                 printf(">>>%s: Started to encrypt output with type %s\r\n",
 849                         Name, ENCTYPE_NAME(type));
 850         if (encrypt_verbose)
 851                 printf("[ Output is now encrypted with type %s ]\r\n",
 852                         ENCTYPE_NAME(type));
 853 }
 854
 855 void
 856 encrypt_send_end(void)
 857 {
 858         if (!encrypt_output)
 859                 return;
 860
 861         str_end[3] = ENCRYPT_END;
 862         net_write(str_end, sizeof(str_end));
 863         net_encrypt();
 864         printsub('>', &str_end[2], sizeof(str_end) - 2);
 865         /*
 866          * Encrypt the output buffer now because it will not be done by
 867          * netflush...
 868          */
 869         encrypt_output = 0;
 870         if (encrypt_debug_mode)
 871                 printf(">>>%s: Output is back to clear text\r\n", Name);
 872         if (encrypt_verbose)
 873                 printf("[ Output is now clear text ]\r\n");
 874 }
 875
 876 void
 877 encrypt_send_request_start(void)
 878 {
 879         unsigned char *p;
 880         int i;
 881
 882         p = &str_start[3];
 883         *p++ = ENCRYPT_REQSTART;
 884         for (i = 0; i < ki[1].keylen; ++i) {
 885                 if ((*p++ = ki[1].keyid[i]) == IAC)
 886                         *p++ = IAC;
 887         }
 888         *p++ = IAC;
 889         *p++ = SE;
 890         net_write(str_start, p - str_start);
 891         printsub('>', &str_start[2], p - &str_start[2]);
 892         if (encrypt_debug_mode)
 893                 printf(">>>%s: Request input to be encrypted\r\n", Name);
 894 }
 895
 896 void
 897 encrypt_send_request_end(void)
 898 {
 899         str_end[3] = ENCRYPT_REQEND;
 900         net_write(str_end, sizeof(str_end));
 901         printsub('>', &str_end[2], sizeof(str_end) - 2);
 902
 903         if (encrypt_debug_mode)
 904                 printf(">>>%s: Request input to be clear text\r\n", Name);
 905 }
 906
 907 void
 908 encrypt_wait(void)
 909 {
 910         if (encrypt_debug_mode)
 911                 printf(">>>%s: in encrypt_wait\r\n", Name);
 912         if (!havesessionkey || !(I_SUPPORT_ENCRYPT & remote_supports_decrypt))
 913                 return;
 914         while (autoencrypt && !encrypt_output)
 915                 if (telnet_spin())
 916                         return;
 917 }
 918
 919 void
 920 encrypt_gen_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
 921 {
 922         char tbuf[16], *cp;
 923
 924         cnt -= 2;
 925         data += 2;
 926         buf[buflen-1] = '\0';
 927         buf[buflen-2] = '*';
 928         buflen -= 2;;
 929         for (; cnt > 0; cnt--, data++) {
 930                 sprintf(tbuf, " %d", *data);
 931                 for (cp = tbuf; *cp && buflen > 0; --buflen)
 932                         *buf++ = *cp++;
 933                 if (buflen <= 0)
 934                         return;
 935         }
 936         *buf = '\0';
 937 }
 938
 939 void
 940 encrypt_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
 941 {
 942         Encryptions *ep;
 943         int type = data[1];
 944
 945         for (ep = encryptions; ep->type && ep->type != type; ep++)
 946                 ;
 947
 948         if (ep->printsub)
 949                 (*ep->printsub)(data, cnt, buf, buflen);
 950         else
 951                 encrypt_gen_printsub(data, cnt, buf, buflen);
 952 }
 953 #endif  /* ENCRYPTION */