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 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31 /*
32 * @(#)Copyright (c) 1994, Simon J. Gerraty.
33 *
34 * This is free software. It comes with NO WARRANTY.
35 * Permission to use, modify and distribute this source code
36 * is granted subject to the following conditions.
37 * 1/ that the above copyright notice and this notice
38 * are preserved in all copies.
39 */
40
41 #include <sys/cdefs.h>
42 #ifndef lint
43 __RCSID("$NetBSD: print-telnet.c,v 1.5 2015/03/31 21:59:35 christos Exp $");
44 #endif
45
46 #define NETDISSECT_REWORKED
47 #ifdef HAVE_CONFIG_H
48 #include "config.h"
49 #endif
50
51 #include <tcpdump-stdinc.h>
52
53 #include <stdio.h>
54
55 #include "interface.h"
56
57 #define TELCMDS
58 #define TELOPTS
59
60 /* NetBSD: telnet.h,v 1.9 2001/06/11 01:50:50 wiz Exp */
61
62 /*
63 * Definitions for the TELNET protocol.
64 */
65 #define IAC 255 /* interpret as command: */
66 #define DONT 254 /* you are not to use option */
67 #define DO 253 /* please, you use option */
68 #define WONT 252 /* I won't use option */
69 #define WILL 251 /* I will use option */
70 #define SB 250 /* interpret as subnegotiation */
71 #define GA 249 /* you may reverse the line */
72 #define EL 248 /* erase the current line */
73 #define EC 247 /* erase the current character */
74 #define AYT 246 /* are you there */
75 #define AO 245 /* abort output--but let prog finish */
76 #define IP 244 /* interrupt process--permanently */
77 #define BREAK 243 /* break */
78 #define DM 242 /* data mark--for connect. cleaning */
79 #define NOP 241 /* nop */
80 #define SE 240 /* end sub negotiation */
81 #define EOR 239 /* end of record (transparent mode) */
82 #define ABORT 238 /* Abort process */
83 #define SUSP 237 /* Suspend process */
84 #define xEOF 236 /* End of file: EOF is already used... */
85
86 #define SYNCH 242 /* for telfunc calls */
87
88 #ifdef TELCMDS
89 const char *telcmds[] = {
90 "EOF", "SUSP", "ABORT", "EOR",
91 "SE", "NOP", "DMARK", "BRK", "IP", "AO", "AYT", "EC",
92 "EL", "GA", "SB", "WILL", "WONT", "DO", "DONT", "IAC", 0,
93 };
94 #else
95 extern char *telcmds[];
96 #endif
97
98 #define TELCMD_FIRST xEOF
99 #define TELCMD_LAST IAC
100 #define TELCMD_OK(x) ((unsigned int)(x) <= TELCMD_LAST && \
101 (unsigned int)(x) >= TELCMD_FIRST)
102 #define TELCMD(x) telcmds[(x)-TELCMD_FIRST]
103
104 /* telnet options */
105 #define TELOPT_BINARY 0 /* 8-bit data path */
106 #define TELOPT_ECHO 1 /* echo */
107 #define TELOPT_RCP 2 /* prepare to reconnect */
108 #define TELOPT_SGA 3 /* suppress go ahead */
109 #define TELOPT_NAMS 4 /* approximate message size */
110 #define TELOPT_STATUS 5 /* give status */
111 #define TELOPT_TM 6 /* timing mark */
112 #define TELOPT_RCTE 7 /* remote controlled transmission and echo */
113 #define TELOPT_NAOL 8 /* negotiate about output line width */
114 #define TELOPT_NAOP 9 /* negotiate about output page size */
115 #define TELOPT_NAOCRD 10 /* negotiate about CR disposition */
116 #define TELOPT_NAOHTS 11 /* negotiate about horizontal tabstops */
117 #define TELOPT_NAOHTD 12 /* negotiate about horizontal tab disposition */
118 #define TELOPT_NAOFFD 13 /* negotiate about formfeed disposition */
119 #define TELOPT_NAOVTS 14 /* negotiate about vertical tab stops */
120 #define TELOPT_NAOVTD 15 /* negotiate about vertical tab disposition */
121 #define TELOPT_NAOLFD 16 /* negotiate about output LF disposition */
122 #define TELOPT_XASCII 17 /* extended ascic character set */
123 #define TELOPT_LOGOUT 18 /* force logout */
124 #define TELOPT_BM 19 /* byte macro */
125 #define TELOPT_DET 20 /* data entry terminal */
126 #define TELOPT_SUPDUP 21 /* supdup protocol */
127 #define TELOPT_SUPDUPOUTPUT 22 /* supdup output */
128 #define TELOPT_SNDLOC 23 /* send location */
129 #define TELOPT_TTYPE 24 /* terminal type */
130 #define TELOPT_EOR 25 /* end or record */
131 #define TELOPT_TUID 26 /* TACACS user identification */
132 #define TELOPT_OUTMRK 27 /* output marking */
133 #define TELOPT_TTYLOC 28 /* terminal location number */
134 #define TELOPT_3270REGIME 29 /* 3270 regime */
135 #define TELOPT_X3PAD 30 /* X.3 PAD */
136 #define TELOPT_NAWS 31 /* window size */
137 #define TELOPT_TSPEED 32 /* terminal speed */
138 #define TELOPT_LFLOW 33 /* remote flow control */
139 #define TELOPT_LINEMODE 34 /* Linemode option */
140 #define TELOPT_XDISPLOC 35 /* X Display Location */
141 #define TELOPT_OLD_ENVIRON 36 /* Old - Environment variables */
142 #define TELOPT_AUTHENTICATION 37/* Authenticate */
143 #define TELOPT_ENCRYPT 38 /* Encryption option */
144 #define TELOPT_NEW_ENVIRON 39 /* New - Environment variables */
145 #define TELOPT_EXOPL 255 /* extended-options-list */
146
147
148 #define NTELOPTS (1+TELOPT_NEW_ENVIRON)
149 #ifdef TELOPTS
150 const char *telopts[NTELOPTS+1] = {
151 "BINARY", "ECHO", "RCP", "SUPPRESS GO AHEAD", "NAME",
152 "STATUS", "TIMING MARK", "RCTE", "NAOL", "NAOP",
153 "NAOCRD", "NAOHTS", "NAOHTD", "NAOFFD", "NAOVTS",
154 "NAOVTD", "NAOLFD", "EXTEND ASCII", "LOGOUT", "BYTE MACRO",
155 "DATA ENTRY TERMINAL", "SUPDUP", "SUPDUP OUTPUT",
156 "SEND LOCATION", "TERMINAL TYPE", "END OF RECORD",
157 "TACACS UID", "OUTPUT MARKING", "TTYLOC",
158 "3270 REGIME", "X.3 PAD", "NAWS", "TSPEED", "LFLOW",
159 "LINEMODE", "XDISPLOC", "OLD-ENVIRON", "AUTHENTICATION",
160 "ENCRYPT", "NEW-ENVIRON",
161 0,
162 };
163 #define TELOPT_FIRST TELOPT_BINARY
164 #define TELOPT_LAST TELOPT_NEW_ENVIRON
165 #define TELOPT_OK(x) ((unsigned int)(x) <= TELOPT_LAST)
166 #define TELOPT(x) telopts[(x)-TELOPT_FIRST]
167 #endif
168
169 /* sub-option qualifiers */
170 #define TELQUAL_IS 0 /* option is... */
171 #define TELQUAL_SEND 1 /* send option */
172 #define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
173 #define TELQUAL_REPLY 2 /* AUTHENTICATION: client version of IS */
174 #define TELQUAL_NAME 3 /* AUTHENTICATION: client version of IS */
175
176 #define LFLOW_OFF 0 /* Disable remote flow control */
177 #define LFLOW_ON 1 /* Enable remote flow control */
178 #define LFLOW_RESTART_ANY 2 /* Restart output on any char */
179 #define LFLOW_RESTART_XON 3 /* Restart output only on XON */
180
181 /*
182 * LINEMODE suboptions
183 */
184
185 #define LM_MODE 1
186 #define LM_FORWARDMASK 2
187 #define LM_SLC 3
188
189 #define MODE_EDIT 0x01
190 #define MODE_TRAPSIG 0x02
191 #define MODE_ACK 0x04
192 #define MODE_SOFT_TAB 0x08
193 #define MODE_LIT_ECHO 0x10
194
195 #define MODE_MASK 0x1f
196
197 #define SLC_SYNCH 1
198 #define SLC_BRK 2
199 #define SLC_IP 3
200 #define SLC_AO 4
201 #define SLC_AYT 5
202 #define SLC_EOR 6
203 #define SLC_ABORT 7
204 #define SLC_EOF 8
205 #define SLC_SUSP 9
206 #define SLC_EC 10
207 #define SLC_EL 11
208 #define SLC_EW 12
209 #define SLC_RP 13
210 #define SLC_LNEXT 14
211 #define SLC_XON 15
212 #define SLC_XOFF 16
213 #define SLC_FORW1 17
214 #define SLC_FORW2 18
215 #define SLC_MCL 19
216 #define SLC_MCR 20
217 #define SLC_MCWL 21
218 #define SLC_MCWR 22
219 #define SLC_MCBOL 23
220 #define SLC_MCEOL 24
221 #define SLC_INSRT 25
222 #define SLC_OVER 26
223 #define SLC_ECR 27
224 #define SLC_EWR 28
225 #define SLC_EBOL 29
226 #define SLC_EEOL 30
227
228 #define NSLC 30
229
230 /*
231 * For backwards compatibility, we define SLC_NAMES to be the
232 * list of names if SLC_NAMES is not defined.
233 */
234 #define SLC_NAMELIST "0", "SYNCH", "BRK", "IP", "AO", "AYT", "EOR", \
235 "ABORT", "EOF", "SUSP", "EC", "EL", "EW", "RP", \
236 "LNEXT", "XON", "XOFF", "FORW1", "FORW2", \
237 "MCL", "MCR", "MCWL", "MCWR", "MCBOL", \
238 "MCEOL", "INSRT", "OVER", "ECR", "EWR", \
239 "EBOL", "EEOL", \
240 0,
241
242 #ifdef SLC_NAMES
243 const char *slc_names[] = {
244 SLC_NAMELIST
245 };
246 #else
247 extern char *slc_names[];
248 #define SLC_NAMES SLC_NAMELIST
249 #endif
250
251 #define SLC_NAME_OK(x) ((unsigned int)(x) <= NSLC)
252 #define SLC_NAME(x) slc_names[x]
253
254 #define SLC_NOSUPPORT 0
255 #define SLC_CANTCHANGE 1
256 #define SLC_VARIABLE 2
257 #define SLC_DEFAULT 3
258 #define SLC_LEVELBITS 0x03
259
260 #define SLC_FUNC 0
261 #define SLC_FLAGS 1
262 #define SLC_VALUE 2
263
264 #define SLC_ACK 0x80
265 #define SLC_FLUSHIN 0x40
266 #define SLC_FLUSHOUT 0x20
267
268 #define OLD_ENV_VAR 1
269 #define OLD_ENV_VALUE 0
270 #define NEW_ENV_VAR 0
271 #define NEW_ENV_VALUE 1
272 #define ENV_ESC 2
273 #define ENV_USERVAR 3
274
275 /*
276 * AUTHENTICATION suboptions
277 */
278
279 /*
280 * Who is authenticating who ...
281 */
282 #define AUTH_WHO_CLIENT 0 /* Client authenticating server */
283 #define AUTH_WHO_SERVER 1 /* Server authenticating client */
284 #define AUTH_WHO_MASK 1
285
286 #define AUTHTYPE_NULL 0
287 #define AUTHTYPE_KERBEROS_V4 1
288 #define AUTHTYPE_KERBEROS_V5 2
289 #define AUTHTYPE_SPX 3
290 #define AUTHTYPE_MINK 4
291 #define AUTHTYPE_CNT 5
292
293 #define AUTHTYPE_TEST 99
294
295 #ifdef AUTH_NAMES
296 const char *authtype_names[] = {
297 "NULL", "KERBEROS_V4", "KERBEROS_V5", "SPX", "MINK", 0,
298 };
299 #else
300 extern char *authtype_names[];
301 #endif
302
303 #define AUTHTYPE_NAME_OK(x) ((unsigned int)(x) < AUTHTYPE_CNT)
304 #define AUTHTYPE_NAME(x) authtype_names[x]
305
306 /*
307 * ENCRYPTion suboptions
308 */
309 #define ENCRYPT_IS 0 /* I pick encryption type ... */
310 #define ENCRYPT_SUPPORT 1 /* I support encryption types ... */
311 #define ENCRYPT_REPLY 2 /* Initial setup response */
312 #define ENCRYPT_START 3 /* Am starting to send encrypted */
313 #define ENCRYPT_END 4 /* Am ending encrypted */
314 #define ENCRYPT_REQSTART 5 /* Request you start encrypting */
315 #define ENCRYPT_REQEND 6 /* Request you send encrypting */
316 #define ENCRYPT_ENC_KEYID 7
317 #define ENCRYPT_DEC_KEYID 8
318 #define ENCRYPT_CNT 9
319
320 #define ENCTYPE_ANY 0
321 #define ENCTYPE_DES_CFB64 1
322 #define ENCTYPE_DES_OFB64 2
323 #define ENCTYPE_CNT 3
324
325 #ifdef ENCRYPT_NAMES
326 const char *encrypt_names[] = {
327 "IS", "SUPPORT", "REPLY", "START", "END",
328 "REQUEST-START", "REQUEST-END", "ENC-KEYID", "DEC-KEYID",
329 0,
330 };
331 const char *enctype_names[] = {
332 "ANY", "DES_CFB64", "DES_OFB64", 0,
333 };
334 #else
335 extern char *encrypt_names[];
336 extern char *enctype_names[];
337 #endif
338
339 #define ENCRYPT_NAME_OK(x) ((unsigned int)(x) < ENCRYPT_CNT)
340 #define ENCRYPT_NAME(x) encrypt_names[x]
341
342 #define ENCTYPE_NAME_OK(x) ((unsigned int)(x) < ENCTYPE_CNT)
343 #define ENCTYPE_NAME(x) enctype_names[x]
344
345 /* normal */
346 static const char *cmds[] = {
347 "IS", "SEND", "INFO",
348 };
349
350 /* 37: Authentication */
351 static const char *authcmd[] = {
352 "IS", "SEND", "REPLY", "NAME",
353 };
354 static const char *authtype[] = {
355 "NULL", "KERBEROS_V4", "KERBEROS_V5", "SPX", "MINK",
356 "SRP", "RSA", "SSL", NULL, NULL,
357 "LOKI", "SSA", "KEA_SJ", "KEA_SJ_INTEG", "DSS",
358 "NTLM",
359 };
360
361 /* 38: Encryption */
362 static const char *enccmd[] = {
363 "IS", "SUPPORT", "REPLY", "START", "END",
364 "REQUEST-START", "REQUEST-END", "END_KEYID", "DEC_KEYID",
365 };
366 static const char *enctype[] = {
367 "NULL", "DES_CFB64", "DES_OFB64", "DES3_CFB64", "DES3_OFB64",
368 NULL, "CAST5_40_CFB64", "CAST5_40_OFB64", "CAST128_CFB64", "CAST128_OFB64",
369 };
370
371 #define STR_OR_ID(x, tab) \
372 (((x) < sizeof(tab)/sizeof(tab[0]) && tab[(x)]) ? tab[(x)] : numstr(x))
373
374 static char *
numstr(int x)375 numstr(int x)
376 {
377 static char buf[20];
378
379 snprintf(buf, sizeof(buf), "%#x", x);
380 return buf;
381 }
382
383 /* sp points to IAC byte */
384 static int
telnet_parse(netdissect_options * ndo,const u_char * sp,u_int length,int print)385 telnet_parse(netdissect_options *ndo, const u_char *sp, u_int length, int print)
386 {
387 int i, x;
388 u_int c;
389 const u_char *osp, *p;
390 #define FETCH(c, sp, length) \
391 do { \
392 if (length < 1) \
393 goto pktend; \
394 ND_TCHECK(*sp); \
395 c = *sp++; \
396 length--; \
397 } while (0)
398
399 osp = sp;
400
401 FETCH(c, sp, length);
402 if (c != IAC)
403 goto pktend;
404 FETCH(c, sp, length);
405 if (c == IAC) { /* <IAC><IAC>! */
406 if (print)
407 ND_PRINT((ndo, "IAC IAC"));
408 goto done;
409 }
410
411 i = c - TELCMD_FIRST;
412 if (i < 0 || i > IAC - TELCMD_FIRST)
413 goto pktend;
414
415 switch (c) {
416 case DONT:
417 case DO:
418 case WONT:
419 case WILL:
420 case SB:
421 /* DONT/DO/WONT/WILL x */
422 FETCH(x, sp, length);
423 if (x >= 0 && x < NTELOPTS) {
424 if (print)
425 ND_PRINT((ndo, "%s %s", telcmds[i], telopts[x]));
426 } else {
427 if (print)
428 ND_PRINT((ndo, "%s %#x", telcmds[i], x));
429 }
430 if (c != SB)
431 break;
432 /* IAC SB .... IAC SE */
433 p = sp;
434 while (length > (u_int)(p + 1 - sp)) {
435 if (p[0] == IAC && p[1] == SE)
436 break;
437 p++;
438 }
439 if (*p != IAC)
440 goto pktend;
441
442 switch (x) {
443 case TELOPT_AUTHENTICATION:
444 if (p <= sp)
445 break;
446 FETCH(c, sp, length);
447 if (print)
448 ND_PRINT((ndo, " %s", STR_OR_ID(c, authcmd)));
449 if (p <= sp)
450 break;
451 FETCH(c, sp, length);
452 if (print)
453 ND_PRINT((ndo, " %s", STR_OR_ID(c, authtype)));
454 break;
455 case TELOPT_ENCRYPT:
456 if (p <= sp)
457 break;
458 FETCH(c, sp, length);
459 if (print)
460 ND_PRINT((ndo, " %s", STR_OR_ID(c, enccmd)));
461 if (p <= sp)
462 break;
463 FETCH(c, sp, length);
464 if (print)
465 ND_PRINT((ndo, " %s", STR_OR_ID(c, enctype)));
466 break;
467 default:
468 if (p <= sp)
469 break;
470 FETCH(c, sp, length);
471 if (print)
472 ND_PRINT((ndo, " %s", STR_OR_ID(c, cmds)));
473 break;
474 }
475 while (p > sp) {
476 FETCH(x, sp, length);
477 if (print)
478 ND_PRINT((ndo, " %#x", x));
479 }
480 /* terminating IAC SE */
481 if (print)
482 ND_PRINT((ndo, " SE"));
483 sp += 2;
484 break;
485 default:
486 if (print)
487 ND_PRINT((ndo, "%s", telcmds[i]));
488 goto done;
489 }
490
491 done:
492 return sp - osp;
493
494 trunc:
495 ND_PRINT((ndo, "[|telnet]"));
496 pktend:
497 return -1;
498 #undef FETCH
499 }
500
501 void
telnet_print(netdissect_options * ndo,const u_char * sp,u_int length)502 telnet_print(netdissect_options *ndo, const u_char *sp, u_int length)
503 {
504 int first = 1;
505 const u_char *osp;
506 int l;
507
508 osp = sp;
509
510 while (length > 0 && *sp == IAC) {
511 /*
512 * Parse the Telnet command without printing it,
513 * to determine its length.
514 */
515 l = telnet_parse(ndo, sp, length, 0);
516 if (l < 0)
517 break;
518
519 /*
520 * now print it
521 */
522 if (ndo->ndo_Xflag && 2 < ndo->ndo_vflag) {
523 if (first)
524 ND_PRINT((ndo, "\nTelnet:"));
525 hex_print_with_offset(ndo, "\n", sp, l, sp - osp);
526 if (l > 8)
527 ND_PRINT((ndo, "\n\t\t\t\t"));
528 else
529 ND_PRINT((ndo, "%*s\t", (8 - l) * 3, ""));
530 } else
531 ND_PRINT((ndo, "%s", (first) ? " [telnet " : ", "));
532
533 (void)telnet_parse(ndo, sp, length, 1);
534 first = 0;
535
536 sp += l;
537 length -= l;
538 }
539 if (!first) {
540 if (ndo->ndo_Xflag && 2 < ndo->ndo_vflag)
541 ND_PRINT((ndo, "\n"));
542 else
543 ND_PRINT((ndo, "]"));
544 }
545 }
546