The Tcpdump Group git mirrors - tcpdump/blob - print-telnet.c

   1 /*      $NetBSD: print-telnet.c,v 1.2 1999/10/11 12:40:12 sjg Exp $     */
   2
   3 /*-
   4  * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code is derived from software contributed to The NetBSD Foundation
   8  * by Simon J. Gerraty.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *        This product includes software developed by the NetBSD
  21  *        Foundation, Inc. and its contributors.
  22  * 4. Neither the name of The NetBSD Foundation nor the names of its
  23  *    contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  36  * POSSIBILITY OF SUCH DAMAGE.
  37  */
  38 /*
  39  *      @(#)Copyright (c) 1994, Simon J. Gerraty.
  40  *
  41  *      This is free software.  It comes with NO WARRANTY.
  42  *      Permission to use, modify and distribute this source code
  43  *      is granted subject to the following conditions.
  44  *      1/ that the above copyright notice and this notice
  45  *      are preserved in all copies.
  46  */
  47
  48 /* \summary: Telnet option printer */
  49
  50 #ifdef HAVE_CONFIG_H
  51 #include "config.h"
  52 #endif
  53
  54 #include <netdissect-stdinc.h>
  55
  56 #include <stdio.h>
  57
  58 #include "netdissect.h"
  59 #include "extract.h"
  60
  61 static const char tstr[] = " [|telnet]";
  62
  63 #define TELCMDS
  64 #define TELOPTS
  65
  66 /*      NetBSD: telnet.h,v 1.9 2001/06/11 01:50:50 wiz Exp      */
  67
  68 /*
  69  * Definitions for the TELNET protocol.
  70  */
  71 #define IAC     255             /* interpret as command: */
  72 #define DONT    254             /* you are not to use option */
  73 #define DO      253             /* please, you use option */
  74 #define WONT    252             /* I won't use option */
  75 #define WILL    251             /* I will use option */
  76 #define SB      250             /* interpret as subnegotiation */
  77 #define GA      249             /* you may reverse the line */
  78 #define EL      248             /* erase the current line */
  79 #define EC      247             /* erase the current character */
  80 #define AYT     246             /* are you there */
  81 #define AO      245             /* abort output--but let prog finish */
  82 #define IP      244             /* interrupt process--permanently */
  83 #define BREAK   243             /* break */
  84 #define DM      242             /* data mark--for connect. cleaning */
  85 #define NOP     241             /* nop */
  86 #define SE      240             /* end sub negotiation */
  87 #define EOR     239             /* end of record (transparent mode) */
  88 #define ABORT   238             /* Abort process */
  89 #define SUSP    237             /* Suspend process */
  90 #define xEOF    236             /* End of file: EOF is already used... */
  91
  92 #define SYNCH   242             /* for telfunc calls */
  93
  94 #ifdef TELCMDS
  95 static const char *telcmds[] = {
  96         "EOF", "SUSP", "ABORT", "EOR",
  97         "SE", "NOP", "DMARK", "BRK", "IP", "AO", "AYT", "EC",
  98         "EL", "GA", "SB", "WILL", "WONT", "DO", "DONT", "IAC", 0,
  99 };
 100 #else
 101 extern char *telcmds[];
 102 #endif
 103
 104 #define TELCMD_FIRST    xEOF
 105 #define TELCMD_LAST     IAC
 106 #define TELCMD_OK(x)    ((unsigned int)(x) <= TELCMD_LAST && \
 107                          (unsigned int)(x) >= TELCMD_FIRST)
 108 #define TELCMD(x)       telcmds[(x)-TELCMD_FIRST]
 109
 110 /* telnet options */
 111 #define TELOPT_BINARY   0       /* 8-bit data path */
 112 #define TELOPT_ECHO     1       /* echo */
 113 #define TELOPT_RCP      2       /* prepare to reconnect */
 114 #define TELOPT_SGA      3       /* suppress go ahead */
 115 #define TELOPT_NAMS     4       /* approximate message size */
 116 #define TELOPT_STATUS   5       /* give status */
 117 #define TELOPT_TM       6       /* timing mark */
 118 #define TELOPT_RCTE     7       /* remote controlled transmission and echo */
 119 #define TELOPT_NAOL     8       /* negotiate about output line width */
 120 #define TELOPT_NAOP     9       /* negotiate about output page size */
 121 #define TELOPT_NAOCRD   10      /* negotiate about CR disposition */
 122 #define TELOPT_NAOHTS   11      /* negotiate about horizontal tabstops */
 123 #define TELOPT_NAOHTD   12      /* negotiate about horizontal tab disposition */
 124 #define TELOPT_NAOFFD   13      /* negotiate about formfeed disposition */
 125 #define TELOPT_NAOVTS   14      /* negotiate about vertical tab stops */
 126 #define TELOPT_NAOVTD   15      /* negotiate about vertical tab disposition */
 127 #define TELOPT_NAOLFD   16      /* negotiate about output LF disposition */
 128 #define TELOPT_XASCII   17      /* extended ascic character set */
 129 #define TELOPT_LOGOUT   18      /* force logout */
 130 #define TELOPT_BM       19      /* byte macro */
 131 #define TELOPT_DET      20      /* data entry terminal */
 132 #define TELOPT_SUPDUP   21      /* supdup protocol */
 133 #define TELOPT_SUPDUPOUTPUT 22  /* supdup output */
 134 #define TELOPT_SNDLOC   23      /* send location */
 135 #define TELOPT_TTYPE    24      /* terminal type */
 136 #define TELOPT_EOR      25      /* end or record */
 137 #define TELOPT_TUID     26      /* TACACS user identification */
 138 #define TELOPT_OUTMRK   27      /* output marking */
 139 #define TELOPT_TTYLOC   28      /* terminal location number */
 140 #define TELOPT_3270REGIME 29    /* 3270 regime */
 141 #define TELOPT_X3PAD    30      /* X.3 PAD */
 142 #define TELOPT_NAWS     31      /* window size */
 143 #define TELOPT_TSPEED   32      /* terminal speed */
 144 #define TELOPT_LFLOW    33      /* remote flow control */
 145 #define TELOPT_LINEMODE 34      /* Linemode option */
 146 #define TELOPT_XDISPLOC 35      /* X Display Location */
 147 #define TELOPT_OLD_ENVIRON 36   /* Old - Environment variables */
 148 #define TELOPT_AUTHENTICATION 37/* Authenticate */
 149 #define TELOPT_ENCRYPT  38      /* Encryption option */
 150 #define TELOPT_NEW_ENVIRON 39   /* New - Environment variables */
 151 #define TELOPT_EXOPL    255     /* extended-options-list */
 152
 153
 154 #define NTELOPTS        (1+TELOPT_NEW_ENVIRON)
 155 #ifdef TELOPTS
 156 static const char *telopts[NTELOPTS+1] = {
 157         "BINARY", "ECHO", "RCP", "SUPPRESS GO AHEAD", "NAME",
 158         "STATUS", "TIMING MARK", "RCTE", "NAOL", "NAOP",
 159         "NAOCRD", "NAOHTS", "NAOHTD", "NAOFFD", "NAOVTS",
 160         "NAOVTD", "NAOLFD", "EXTEND ASCII", "LOGOUT", "BYTE MACRO",
 161         "DATA ENTRY TERMINAL", "SUPDUP", "SUPDUP OUTPUT",
 162         "SEND LOCATION", "TERMINAL TYPE", "END OF RECORD",
 163         "TACACS UID", "OUTPUT MARKING", "TTYLOC",
 164         "3270 REGIME", "X.3 PAD", "NAWS", "TSPEED", "LFLOW",
 165         "LINEMODE", "XDISPLOC", "OLD-ENVIRON", "AUTHENTICATION",
 166         "ENCRYPT", "NEW-ENVIRON",
 167         0,
 168 };
 169 #define TELOPT_FIRST    TELOPT_BINARY
 170 #define TELOPT_LAST     TELOPT_NEW_ENVIRON
 171 #define TELOPT_OK(x)    ((unsigned int)(x) <= TELOPT_LAST)
 172 #define TELOPT(x)       telopts[(x)-TELOPT_FIRST]
 173 #endif
 174
 175 /* sub-option qualifiers */
 176 #define TELQUAL_IS      0       /* option is... */
 177 #define TELQUAL_SEND    1       /* send option */
 178 #define TELQUAL_INFO    2       /* ENVIRON: informational version of IS */
 179 #define TELQUAL_REPLY   2       /* AUTHENTICATION: client version of IS */
 180 #define TELQUAL_NAME    3       /* AUTHENTICATION: client version of IS */
 181
 182 #define LFLOW_OFF               0       /* Disable remote flow control */
 183 #define LFLOW_ON                1       /* Enable remote flow control */
 184 #define LFLOW_RESTART_ANY       2       /* Restart output on any char */
 185 #define LFLOW_RESTART_XON       3       /* Restart output only on XON */
 186
 187 /*
 188  * LINEMODE suboptions
 189  */
 190
 191 #define LM_MODE         1
 192 #define LM_FORWARDMASK  2
 193 #define LM_SLC          3
 194
 195 #define MODE_EDIT       0x01
 196 #define MODE_TRAPSIG    0x02
 197 #define MODE_ACK        0x04
 198 #define MODE_SOFT_TAB   0x08
 199 #define MODE_LIT_ECHO   0x10
 200
 201 #define MODE_MASK       0x1f
 202
 203 #define SLC_SYNCH       1
 204 #define SLC_BRK         2
 205 #define SLC_IP          3
 206 #define SLC_AO          4
 207 #define SLC_AYT         5
 208 #define SLC_EOR         6
 209 #define SLC_ABORT       7
 210 #define SLC_EOF         8
 211 #define SLC_SUSP        9
 212 #define SLC_EC          10
 213 #define SLC_EL          11
 214 #define SLC_EW          12
 215 #define SLC_RP          13
 216 #define SLC_LNEXT       14
 217 #define SLC_XON         15
 218 #define SLC_XOFF        16
 219 #define SLC_FORW1       17
 220 #define SLC_FORW2       18
 221 #define SLC_MCL         19
 222 #define SLC_MCR         20
 223 #define SLC_MCWL        21
 224 #define SLC_MCWR        22
 225 #define SLC_MCBOL       23
 226 #define SLC_MCEOL       24
 227 #define SLC_INSRT       25
 228 #define SLC_OVER        26
 229 #define SLC_ECR         27
 230 #define SLC_EWR         28
 231 #define SLC_EBOL        29
 232 #define SLC_EEOL        30
 233
 234 #define NSLC            30
 235
 236 /*
 237  * For backwards compatibility, we define SLC_NAMES to be the
 238  * list of names if SLC_NAMES is not defined.
 239  */
 240 #define SLC_NAMELIST    "0", "SYNCH", "BRK", "IP", "AO", "AYT", "EOR",  \
 241                         "ABORT", "EOF", "SUSP", "EC", "EL", "EW", "RP", \
 242                         "LNEXT", "XON", "XOFF", "FORW1", "FORW2",       \
 243                         "MCL", "MCR", "MCWL", "MCWR", "MCBOL",          \
 244                         "MCEOL", "INSRT", "OVER", "ECR", "EWR",         \
 245                         "EBOL", "EEOL",                                 \
 246                         0,
 247
 248 #ifdef  SLC_NAMES
 249 const char *slc_names[] = {
 250         SLC_NAMELIST
 251 };
 252 #else
 253 extern char *slc_names[];
 254 #define SLC_NAMES SLC_NAMELIST
 255 #endif
 256
 257 #define SLC_NAME_OK(x)  ((unsigned int)(x) <= NSLC)
 258 #define SLC_NAME(x)     slc_names[x]
 259
 260 #define SLC_NOSUPPORT   0
 261 #define SLC_CANTCHANGE  1
 262 #define SLC_VARIABLE    2
 263 #define SLC_DEFAULT     3
 264 #define SLC_LEVELBITS   0x03
 265
 266 #define SLC_FUNC        0
 267 #define SLC_FLAGS       1
 268 #define SLC_VALUE       2
 269
 270 #define SLC_ACK         0x80
 271 #define SLC_FLUSHIN     0x40
 272 #define SLC_FLUSHOUT    0x20
 273
 274 #define OLD_ENV_VAR     1
 275 #define OLD_ENV_VALUE   0
 276 #define NEW_ENV_VAR     0
 277 #define NEW_ENV_VALUE   1
 278 #define ENV_ESC         2
 279 #define ENV_USERVAR     3
 280
 281 /*
 282  * AUTHENTICATION suboptions
 283  */
 284
 285 /*
 286  * Who is authenticating who ...
 287  */
 288 #define AUTH_WHO_CLIENT         0       /* Client authenticating server */
 289 #define AUTH_WHO_SERVER         1       /* Server authenticating client */
 290 #define AUTH_WHO_MASK           1
 291
 292 #define AUTHTYPE_NULL           0
 293 #define AUTHTYPE_KERBEROS_V4    1
 294 #define AUTHTYPE_KERBEROS_V5    2
 295 #define AUTHTYPE_SPX            3
 296 #define AUTHTYPE_MINK           4
 297 #define AUTHTYPE_CNT            5
 298
 299 #define AUTHTYPE_TEST           99
 300
 301 #ifdef  AUTH_NAMES
 302 const char *authtype_names[] = {
 303         "NULL", "KERBEROS_V4", "KERBEROS_V5", "SPX", "MINK", 0,
 304 };
 305 #else
 306 extern char *authtype_names[];
 307 #endif
 308
 309 #define AUTHTYPE_NAME_OK(x)     ((unsigned int)(x) < AUTHTYPE_CNT)
 310 #define AUTHTYPE_NAME(x)        authtype_names[x]
 311
 312 /*
 313  * ENCRYPTion suboptions
 314  */
 315 #define ENCRYPT_IS              0       /* I pick encryption type ... */
 316 #define ENCRYPT_SUPPORT         1       /* I support encryption types ... */
 317 #define ENCRYPT_REPLY           2       /* Initial setup response */
 318 #define ENCRYPT_START           3       /* Am starting to send encrypted */
 319 #define ENCRYPT_END             4       /* Am ending encrypted */
 320 #define ENCRYPT_REQSTART        5       /* Request you start encrypting */
 321 #define ENCRYPT_REQEND          6       /* Request you send encrypting */
 322 #define ENCRYPT_ENC_KEYID       7
 323 #define ENCRYPT_DEC_KEYID       8
 324 #define ENCRYPT_CNT             9
 325
 326 #define ENCTYPE_ANY             0
 327 #define ENCTYPE_DES_CFB64       1
 328 #define ENCTYPE_DES_OFB64       2
 329 #define ENCTYPE_CNT             3
 330
 331 #ifdef  ENCRYPT_NAMES
 332 const char *encrypt_names[] = {
 333         "IS", "SUPPORT", "REPLY", "START", "END",
 334         "REQUEST-START", "REQUEST-END", "ENC-KEYID", "DEC-KEYID",
 335         0,
 336 };
 337 const char *enctype_names[] = {
 338         "ANY", "DES_CFB64",  "DES_OFB64",  0,
 339 };
 340 #else
 341 extern char *encrypt_names[];
 342 extern char *enctype_names[];
 343 #endif
 344
 345 #define ENCRYPT_NAME_OK(x)      ((unsigned int)(x) < ENCRYPT_CNT)
 346 #define ENCRYPT_NAME(x)         encrypt_names[x]
 347
 348 #define ENCTYPE_NAME_OK(x)      ((unsigned int)(x) < ENCTYPE_CNT)
 349 #define ENCTYPE_NAME(x)         enctype_names[x]
 350
 351 /* normal */
 352 static const char *cmds[] = {
 353         "IS", "SEND", "INFO",
 354 };
 355
 356 /* 37: Authentication */
 357 static const char *authcmd[] = {
 358         "IS", "SEND", "REPLY", "NAME",
 359 };
 360 static const char *authtype[] = {
 361         "NULL", "KERBEROS_V4", "KERBEROS_V5", "SPX", "MINK",
 362         "SRP", "RSA", "SSL", NULL, NULL,
 363         "LOKI", "SSA", "KEA_SJ", "KEA_SJ_INTEG", "DSS",
 364         "NTLM",
 365 };
 366
 367 /* 38: Encryption */
 368 static const char *enccmd[] = {
 369         "IS", "SUPPORT", "REPLY", "START", "END",
 370         "REQUEST-START", "REQUEST-END", "END_KEYID", "DEC_KEYID",
 371 };
 372 static const char *enctype[] = {
 373         "NULL", "DES_CFB64", "DES_OFB64", "DES3_CFB64", "DES3_OFB64",
 374         NULL, "CAST5_40_CFB64", "CAST5_40_OFB64", "CAST128_CFB64", "CAST128_OFB64",
 375 };
 376
 377 #define STR_OR_ID(x, tab) \
 378         (((x) < sizeof(tab)/sizeof(tab[0]) && tab[(x)]) ? tab[(x)] : numstr(x))
 379
 380 static char *
 381 numstr(int x)
 382 {
 383         static char buf[20];
 384
 385         snprintf(buf, sizeof(buf), "%#x", x);
 386         return buf;
 387 }
 388
 389 /* sp points to IAC byte */
 390 static int
 391 telnet_parse(netdissect_options *ndo, const u_char *sp, u_int length, int print)
 392 {
 393         int i, x;
 394         u_int c;
 395         const u_char *osp, *p;
 396 #define FETCH(c, sp, length) \
 397         do { \
 398                 if (length < 1) \
 399                         goto pktend; \
 400                 ND_TCHECK(*sp); \
 401                 c = *sp++; \
 402                 length--; \
 403         } while (0)
 404
 405         osp = sp;
 406
 407         FETCH(c, sp, length);
 408         if (c != IAC)
 409                 goto pktend;
 410         FETCH(c, sp, length);
 411         if (c == IAC) {         /* <IAC><IAC>! */
 412                 if (print)
 413                         ND_PRINT((ndo, "IAC IAC"));
 414                 goto done;
 415         }
 416
 417         i = c - TELCMD_FIRST;
 418         if (i < 0 || i > IAC - TELCMD_FIRST)
 419                 goto pktend;
 420
 421         switch (c) {
 422         case DONT:
 423         case DO:
 424         case WONT:
 425         case WILL:
 426         case SB:
 427                 /* DONT/DO/WONT/WILL x */
 428                 FETCH(x, sp, length);
 429                 if (x >= 0 && x < NTELOPTS) {
 430                         if (print)
 431                                 ND_PRINT((ndo, "%s %s", telcmds[i], telopts[x]));
 432                 } else {
 433                         if (print)
 434                                 ND_PRINT((ndo, "%s %#x", telcmds[i], x));
 435                 }
 436                 if (c != SB)
 437                         break;
 438                 /* IAC SB .... IAC SE */
 439                 p = sp;
 440                 while (length > (u_int)(p + 1 - sp)) {
 441                         ND_TCHECK_2(p);
 442                         if (EXTRACT_U_1(p) == IAC && EXTRACT_U_1(p + 1) == SE)
 443                                 break;
 444                         p++;
 445                 }
 446                 ND_TCHECK_1(p);
 447                 if (*p != IAC)
 448                         goto pktend;
 449
 450                 switch (x) {
 451                 case TELOPT_AUTHENTICATION:
 452                         if (p <= sp)
 453                                 break;
 454                         FETCH(c, sp, length);
 455                         if (print)
 456                                 ND_PRINT((ndo, " %s", STR_OR_ID(c, authcmd)));
 457                         if (p <= sp)
 458                                 break;
 459                         FETCH(c, sp, length);
 460                         if (print)
 461                                 ND_PRINT((ndo, " %s", STR_OR_ID(c, authtype)));
 462                         break;
 463                 case TELOPT_ENCRYPT:
 464                         if (p <= sp)
 465                                 break;
 466                         FETCH(c, sp, length);
 467                         if (print)
 468                                 ND_PRINT((ndo, " %s", STR_OR_ID(c, enccmd)));
 469                         if (p <= sp)
 470                                 break;
 471                         FETCH(c, sp, length);
 472                         if (print)
 473                                 ND_PRINT((ndo, " %s", STR_OR_ID(c, enctype)));
 474                         break;
 475                 default:
 476                         if (p <= sp)
 477                                 break;
 478                         FETCH(c, sp, length);
 479                         if (print)
 480                                 ND_PRINT((ndo, " %s", STR_OR_ID(c, cmds)));
 481                         break;
 482                 }
 483                 while (p > sp) {
 484                         FETCH(x, sp, length);
 485                         if (print)
 486                                 ND_PRINT((ndo, " %#x", x));
 487                 }
 488                 /* terminating IAC SE */
 489                 if (print)
 490                         ND_PRINT((ndo, " SE"));
 491                 sp += 2;
 492                 break;
 493         default:
 494                 if (print)
 495                         ND_PRINT((ndo, "%s", telcmds[i]));
 496                 goto done;
 497         }
 498
 499 done:
 500         return sp - osp;
 501
 502 trunc:
 503         ND_PRINT((ndo, "%s", tstr));
 504 pktend:
 505         return -1;
 506 #undef FETCH
 507 }
 508
 509 void
 510 telnet_print(netdissect_options *ndo, const u_char *sp, u_int length)
 511 {
 512         int first = 1;
 513         const u_char *osp;
 514         int l;
 515
 516         osp = sp;
 517
 518         ND_TCHECK_1(sp);
 519         while (length > 0 && EXTRACT_U_1(sp) == IAC) {
 520                 /*
 521                  * Parse the Telnet command without printing it,
 522                  * to determine its length.
 523                  */
 524                 l = telnet_parse(ndo, sp, length, 0);
 525                 if (l < 0)
 526                         break;
 527
 528                 /*
 529                  * now print it
 530                  */
 531                 if (ndo->ndo_Xflag && 2 < ndo->ndo_vflag) {
 532                         if (first)
 533                                 ND_PRINT((ndo, "\nTelnet:"));
 534                         hex_print_with_offset(ndo, "\n", sp, l, sp - osp);
 535                         if (l > 8)
 536                                 ND_PRINT((ndo, "\n\t\t\t\t"));
 537                         else
 538                                 ND_PRINT((ndo, "%*s\t", (8 - l) * 3, ""));
 539                 } else
 540                         ND_PRINT((ndo, "%s", (first) ? " [telnet " : ", "));
 541
 542                 (void)telnet_parse(ndo, sp, length, 1);
 543                 first = 0;
 544
 545                 sp += l;
 546                 length -= l;
 547                 ND_TCHECK_1(sp);
 548         }
 549         if (!first) {
 550                 if (ndo->ndo_Xflag && 2 < ndo->ndo_vflag)
 551                         ND_PRINT((ndo, "\n"));
 552                 else
 553                         ND_PRINT((ndo, "]"));
 554         }
 555         return;
 556 trunc:
 557         ND_PRINT((ndo, "%s", tstr));
 558 }