1 /* $OpenBSD: ttymodes.c,v 1.30 2016/05/04 14:22:33 markus Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 *
7 * As far as I am concerned, the code I have written for this software
8 * can be used freely for any purpose. Any derived versions of this
9 * software must be clearly marked as such, and if the derived work is
10 * incompatible with the protocol description in the RFC file, it must be
11 * called by a name other than "ssh" or "Secure Shell".
12 */
13
14 /*
15 * SSH2 tty modes support by Kevin Steves.
16 * Copyright (c) 2001 Kevin Steves. All rights reserved.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
20 * are met:
21 * 1. Redistributions of source code must retain the above copyright
22 * notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 * notice, this list of conditions and the following disclaimer in the
25 * documentation and/or other materials provided with the distribution.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37 */
38
39 /*
40 * Encoding and decoding of terminal modes in a portable way.
41 * Much of the format is defined in ttymodes.h; it is included multiple times
42 * into this file with the appropriate macro definitions to generate the
43 * suitable code.
44 */
45
46 #include "includes.h"
47
48 #include <sys/types.h>
49
50 #include <errno.h>
51 #include <string.h>
52 #include <termios.h>
53 #include <stdarg.h>
54
55 #include "packet.h"
56 #include "log.h"
57 #include "compat.h"
58 #include "buffer.h"
59
60 #define TTY_OP_END 0
61 /*
62 * uint32 (u_int) follows speed in SSH1 and SSH2
63 */
64 #define TTY_OP_ISPEED_PROTO1 192
65 #define TTY_OP_OSPEED_PROTO1 193
66 #define TTY_OP_ISPEED_PROTO2 128
67 #define TTY_OP_OSPEED_PROTO2 129
68
69 /*
70 * Converts POSIX speed_t to a baud rate. The values of the
71 * constants for speed_t are not themselves portable.
72 */
73 static int
speed_to_baud(speed_t speed)74 speed_to_baud(speed_t speed)
75 {
76 switch (speed) {
77 case B0:
78 return 0;
79 case B50:
80 return 50;
81 case B75:
82 return 75;
83 case B110:
84 return 110;
85 case B134:
86 return 134;
87 case B150:
88 return 150;
89 case B200:
90 return 200;
91 case B300:
92 return 300;
93 case B600:
94 return 600;
95 case B1200:
96 return 1200;
97 case B1800:
98 return 1800;
99 case B2400:
100 return 2400;
101 case B4800:
102 return 4800;
103 case B9600:
104 return 9600;
105
106 #ifdef B19200
107 case B19200:
108 return 19200;
109 #else /* B19200 */
110 #ifdef EXTA
111 case EXTA:
112 return 19200;
113 #endif /* EXTA */
114 #endif /* B19200 */
115
116 #ifdef B38400
117 case B38400:
118 return 38400;
119 #else /* B38400 */
120 #ifdef EXTB
121 case EXTB:
122 return 38400;
123 #endif /* EXTB */
124 #endif /* B38400 */
125
126 #ifdef B7200
127 case B7200:
128 return 7200;
129 #endif /* B7200 */
130 #ifdef B14400
131 case B14400:
132 return 14400;
133 #endif /* B14400 */
134 #ifdef B28800
135 case B28800:
136 return 28800;
137 #endif /* B28800 */
138 #ifdef B57600
139 case B57600:
140 return 57600;
141 #endif /* B57600 */
142 #ifdef B76800
143 case B76800:
144 return 76800;
145 #endif /* B76800 */
146 #ifdef B115200
147 case B115200:
148 return 115200;
149 #endif /* B115200 */
150 #ifdef B230400
151 case B230400:
152 return 230400;
153 #endif /* B230400 */
154 default:
155 return 9600;
156 }
157 }
158
159 /*
160 * Converts a numeric baud rate to a POSIX speed_t.
161 */
162 static speed_t
baud_to_speed(int baud)163 baud_to_speed(int baud)
164 {
165 switch (baud) {
166 case 0:
167 return B0;
168 case 50:
169 return B50;
170 case 75:
171 return B75;
172 case 110:
173 return B110;
174 case 134:
175 return B134;
176 case 150:
177 return B150;
178 case 200:
179 return B200;
180 case 300:
181 return B300;
182 case 600:
183 return B600;
184 case 1200:
185 return B1200;
186 case 1800:
187 return B1800;
188 case 2400:
189 return B2400;
190 case 4800:
191 return B4800;
192 case 9600:
193 return B9600;
194
195 #ifdef B19200
196 case 19200:
197 return B19200;
198 #else /* B19200 */
199 #ifdef EXTA
200 case 19200:
201 return EXTA;
202 #endif /* EXTA */
203 #endif /* B19200 */
204
205 #ifdef B38400
206 case 38400:
207 return B38400;
208 #else /* B38400 */
209 #ifdef EXTB
210 case 38400:
211 return EXTB;
212 #endif /* EXTB */
213 #endif /* B38400 */
214
215 #ifdef B7200
216 case 7200:
217 return B7200;
218 #endif /* B7200 */
219 #ifdef B14400
220 case 14400:
221 return B14400;
222 #endif /* B14400 */
223 #ifdef B28800
224 case 28800:
225 return B28800;
226 #endif /* B28800 */
227 #ifdef B57600
228 case 57600:
229 return B57600;
230 #endif /* B57600 */
231 #ifdef B76800
232 case 76800:
233 return B76800;
234 #endif /* B76800 */
235 #ifdef B115200
236 case 115200:
237 return B115200;
238 #endif /* B115200 */
239 #ifdef B230400
240 case 230400:
241 return B230400;
242 #endif /* B230400 */
243 default:
244 return B9600;
245 }
246 }
247
248 /*
249 * Encode a special character into SSH line format.
250 */
251 static u_int
special_char_encode(cc_t c)252 special_char_encode(cc_t c)
253 {
254 #ifdef _POSIX_VDISABLE
255 if (c == _POSIX_VDISABLE)
256 return 255;
257 #endif /* _POSIX_VDISABLE */
258 return c;
259 }
260
261 /*
262 * Decode a special character from SSH line format.
263 */
264 static cc_t
special_char_decode(u_int c)265 special_char_decode(u_int c)
266 {
267 #ifdef _POSIX_VDISABLE
268 if (c == 255)
269 return _POSIX_VDISABLE;
270 #endif /* _POSIX_VDISABLE */
271 return c;
272 }
273
274 /*
275 * Encodes terminal modes for the terminal referenced by fd
276 * or tiop in a portable manner, and appends the modes to a packet
277 * being constructed.
278 */
279 void
tty_make_modes(int fd,struct termios * tiop)280 tty_make_modes(int fd, struct termios *tiop)
281 {
282 struct termios tio;
283 int baud;
284 Buffer buf;
285 int tty_op_ospeed, tty_op_ispeed;
286 void (*put_arg)(Buffer *, u_int);
287
288 buffer_init(&buf);
289 if (compat20) {
290 tty_op_ospeed = TTY_OP_OSPEED_PROTO2;
291 tty_op_ispeed = TTY_OP_ISPEED_PROTO2;
292 put_arg = buffer_put_int;
293 } else {
294 tty_op_ospeed = TTY_OP_OSPEED_PROTO1;
295 tty_op_ispeed = TTY_OP_ISPEED_PROTO1;
296 put_arg = (void (*)(Buffer *, u_int)) buffer_put_char;
297 }
298
299 if (tiop == NULL) {
300 if (fd == -1) {
301 debug("tty_make_modes: no fd or tio");
302 goto end;
303 }
304 if (tcgetattr(fd, &tio) == -1) {
305 logit("tcgetattr: %.100s", strerror(errno));
306 goto end;
307 }
308 } else
309 tio = *tiop;
310
311 /* Store input and output baud rates. */
312 baud = speed_to_baud(cfgetospeed(&tio));
313 buffer_put_char(&buf, tty_op_ospeed);
314 buffer_put_int(&buf, baud);
315 baud = speed_to_baud(cfgetispeed(&tio));
316 buffer_put_char(&buf, tty_op_ispeed);
317 buffer_put_int(&buf, baud);
318
319 /* Store values of mode flags. */
320 #define TTYCHAR(NAME, OP) \
321 buffer_put_char(&buf, OP); \
322 put_arg(&buf, special_char_encode(tio.c_cc[NAME]));
323
324 #define TTYMODE(NAME, FIELD, OP) \
325 buffer_put_char(&buf, OP); \
326 put_arg(&buf, ((tio.FIELD & NAME) != 0));
327
328 #include "ttymodes.h"
329
330 #undef TTYCHAR
331 #undef TTYMODE
332
333 end:
334 /* Mark end of mode data. */
335 buffer_put_char(&buf, TTY_OP_END);
336 if (compat20)
337 packet_put_string(buffer_ptr(&buf), buffer_len(&buf));
338 else
339 packet_put_raw(buffer_ptr(&buf), buffer_len(&buf));
340 buffer_free(&buf);
341 }
342
343 /*
344 * Decodes terminal modes for the terminal referenced by fd in a portable
345 * manner from a packet being read.
346 */
347 void
tty_parse_modes(int fd,int * n_bytes_ptr)348 tty_parse_modes(int fd, int *n_bytes_ptr)
349 {
350 struct termios tio;
351 int opcode, baud;
352 int n_bytes = 0;
353 int failure = 0;
354 u_int (*get_arg)(void);
355 int arg_size;
356
357 if (compat20) {
358 *n_bytes_ptr = packet_get_int();
359 if (*n_bytes_ptr == 0)
360 return;
361 get_arg = packet_get_int;
362 arg_size = 4;
363 } else {
364 get_arg = packet_get_char;
365 arg_size = 1;
366 }
367
368 /*
369 * Get old attributes for the terminal. We will modify these
370 * flags. I am hoping that if there are any machine-specific
371 * modes, they will initially have reasonable values.
372 */
373 if (tcgetattr(fd, &tio) == -1) {
374 logit("tcgetattr: %.100s", strerror(errno));
375 failure = -1;
376 }
377
378 for (;;) {
379 n_bytes += 1;
380 opcode = packet_get_char();
381 switch (opcode) {
382 case TTY_OP_END:
383 goto set;
384
385 /* XXX: future conflict possible */
386 case TTY_OP_ISPEED_PROTO1:
387 case TTY_OP_ISPEED_PROTO2:
388 n_bytes += 4;
389 baud = packet_get_int();
390 if (failure != -1 &&
391 cfsetispeed(&tio, baud_to_speed(baud)) == -1)
392 error("cfsetispeed failed for %d", baud);
393 break;
394
395 /* XXX: future conflict possible */
396 case TTY_OP_OSPEED_PROTO1:
397 case TTY_OP_OSPEED_PROTO2:
398 n_bytes += 4;
399 baud = packet_get_int();
400 if (failure != -1 &&
401 cfsetospeed(&tio, baud_to_speed(baud)) == -1)
402 error("cfsetospeed failed for %d", baud);
403 break;
404
405 #define TTYCHAR(NAME, OP) \
406 case OP: \
407 n_bytes += arg_size; \
408 tio.c_cc[NAME] = special_char_decode(get_arg()); \
409 break;
410 #define TTYMODE(NAME, FIELD, OP) \
411 case OP: \
412 n_bytes += arg_size; \
413 if (get_arg()) \
414 tio.FIELD |= NAME; \
415 else \
416 tio.FIELD &= ~NAME; \
417 break;
418
419 #include "ttymodes.h"
420
421 #undef TTYCHAR
422 #undef TTYMODE
423
424 default:
425 debug("Ignoring unsupported tty mode opcode %d (0x%x)",
426 opcode, opcode);
427 if (!compat20) {
428 /*
429 * SSH1:
430 * Opcodes 1 to 127 are defined to have
431 * a one-byte argument.
432 * Opcodes 128 to 159 are defined to have
433 * an integer argument.
434 */
435 if (opcode > 0 && opcode < 128) {
436 n_bytes += 1;
437 (void) packet_get_char();
438 break;
439 } else if (opcode >= 128 && opcode < 160) {
440 n_bytes += 4;
441 (void) packet_get_int();
442 break;
443 } else {
444 /*
445 * It is a truly undefined opcode (160 to 255).
446 * We have no idea about its arguments. So we
447 * must stop parsing. Note that some data
448 * may be left in the packet; hopefully there
449 * is nothing more coming after the mode data.
450 */
451 logit("parse_tty_modes: unknown opcode %d",
452 opcode);
453 goto set;
454 }
455 } else {
456 /*
457 * SSH2:
458 * Opcodes 1 to 159 are defined to have
459 * a uint32 argument.
460 * Opcodes 160 to 255 are undefined and
461 * cause parsing to stop.
462 */
463 if (opcode > 0 && opcode < 160) {
464 n_bytes += 4;
465 (void) packet_get_int();
466 break;
467 } else {
468 logit("parse_tty_modes: unknown opcode %d",
469 opcode);
470 goto set;
471 }
472 }
473 }
474 }
475
476 set:
477 if (*n_bytes_ptr != n_bytes) {
478 *n_bytes_ptr = n_bytes;
479 logit("parse_tty_modes: n_bytes_ptr != n_bytes: %d %d",
480 *n_bytes_ptr, n_bytes);
481 return; /* Don't process bytes passed */
482 }
483 if (failure == -1)
484 return; /* Packet parsed ok but tcgetattr() failed */
485
486 /* Set the new modes for the terminal. */
487 if (tcsetattr(fd, TCSANOW, &tio) == -1)
488 logit("Setting tty modes failed: %.100s", strerror(errno));
489 }
490