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