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