xref: /openbsd-src/usr.bin/ssh/ttymodes.c (revision 0b7734b3d77bb9b21afec6f4621cae6c805dbd45)
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 <sys/types.h>
47 
48 #include <errno.h>
49 #include <string.h>
50 #include <termios.h>
51 #include <stdarg.h>
52 
53 #include "packet.h"
54 #include "log.h"
55 #include "compat.h"
56 #include "buffer.h"
57 
58 #define TTY_OP_END		0
59 /*
60  * uint32 (u_int) follows speed in SSH1 and SSH2
61  */
62 #define TTY_OP_ISPEED_PROTO1	192
63 #define TTY_OP_OSPEED_PROTO1	193
64 #define TTY_OP_ISPEED_PROTO2	128
65 #define TTY_OP_OSPEED_PROTO2	129
66 
67 /*
68  * Converts POSIX speed_t to a baud rate.  The values of the
69  * constants for speed_t are not themselves portable.
70  */
71 static int
72 speed_to_baud(speed_t speed)
73 {
74 	switch (speed) {
75 	case B0:
76 		return 0;
77 	case B50:
78 		return 50;
79 	case B75:
80 		return 75;
81 	case B110:
82 		return 110;
83 	case B134:
84 		return 134;
85 	case B150:
86 		return 150;
87 	case B200:
88 		return 200;
89 	case B300:
90 		return 300;
91 	case B600:
92 		return 600;
93 	case B1200:
94 		return 1200;
95 	case B1800:
96 		return 1800;
97 	case B2400:
98 		return 2400;
99 	case B4800:
100 		return 4800;
101 	case B9600:
102 		return 9600;
103 
104 #ifdef B19200
105 	case B19200:
106 		return 19200;
107 #else /* B19200 */
108 #ifdef EXTA
109 	case EXTA:
110 		return 19200;
111 #endif /* EXTA */
112 #endif /* B19200 */
113 
114 #ifdef B38400
115 	case B38400:
116 		return 38400;
117 #else /* B38400 */
118 #ifdef EXTB
119 	case EXTB:
120 		return 38400;
121 #endif /* EXTB */
122 #endif /* B38400 */
123 
124 #ifdef B7200
125 	case B7200:
126 		return 7200;
127 #endif /* B7200 */
128 #ifdef B14400
129 	case B14400:
130 		return 14400;
131 #endif /* B14400 */
132 #ifdef B28800
133 	case B28800:
134 		return 28800;
135 #endif /* B28800 */
136 #ifdef B57600
137 	case B57600:
138 		return 57600;
139 #endif /* B57600 */
140 #ifdef B76800
141 	case B76800:
142 		return 76800;
143 #endif /* B76800 */
144 #ifdef B115200
145 	case B115200:
146 		return 115200;
147 #endif /* B115200 */
148 #ifdef B230400
149 	case B230400:
150 		return 230400;
151 #endif /* B230400 */
152 	default:
153 		return 9600;
154 	}
155 }
156 
157 /*
158  * Converts a numeric baud rate to a POSIX speed_t.
159  */
160 static speed_t
161 baud_to_speed(int baud)
162 {
163 	switch (baud) {
164 	case 0:
165 		return B0;
166 	case 50:
167 		return B50;
168 	case 75:
169 		return B75;
170 	case 110:
171 		return B110;
172 	case 134:
173 		return B134;
174 	case 150:
175 		return B150;
176 	case 200:
177 		return B200;
178 	case 300:
179 		return B300;
180 	case 600:
181 		return B600;
182 	case 1200:
183 		return B1200;
184 	case 1800:
185 		return B1800;
186 	case 2400:
187 		return B2400;
188 	case 4800:
189 		return B4800;
190 	case 9600:
191 		return B9600;
192 
193 #ifdef B19200
194 	case 19200:
195 		return B19200;
196 #else /* B19200 */
197 #ifdef EXTA
198 	case 19200:
199 		return EXTA;
200 #endif /* EXTA */
201 #endif /* B19200 */
202 
203 #ifdef B38400
204 	case 38400:
205 		return B38400;
206 #else /* B38400 */
207 #ifdef EXTB
208 	case 38400:
209 		return EXTB;
210 #endif /* EXTB */
211 #endif /* B38400 */
212 
213 #ifdef B7200
214 	case 7200:
215 		return B7200;
216 #endif /* B7200 */
217 #ifdef B14400
218 	case 14400:
219 		return B14400;
220 #endif /* B14400 */
221 #ifdef B28800
222 	case 28800:
223 		return B28800;
224 #endif /* B28800 */
225 #ifdef B57600
226 	case 57600:
227 		return B57600;
228 #endif /* B57600 */
229 #ifdef B76800
230 	case 76800:
231 		return B76800;
232 #endif /* B76800 */
233 #ifdef B115200
234 	case 115200:
235 		return B115200;
236 #endif /* B115200 */
237 #ifdef B230400
238 	case 230400:
239 		return B230400;
240 #endif /* B230400 */
241 	default:
242 		return B9600;
243 	}
244 }
245 
246 /*
247  * Encodes terminal modes for the terminal referenced by fd
248  * or tiop in a portable manner, and appends the modes to a packet
249  * being constructed.
250  */
251 void
252 tty_make_modes(int fd, struct termios *tiop)
253 {
254 	struct termios tio;
255 	int baud;
256 	Buffer buf;
257 	int tty_op_ospeed, tty_op_ispeed;
258 	void (*put_arg)(Buffer *, u_int);
259 
260 	buffer_init(&buf);
261 	if (compat20) {
262 		tty_op_ospeed = TTY_OP_OSPEED_PROTO2;
263 		tty_op_ispeed = TTY_OP_ISPEED_PROTO2;
264 		put_arg = buffer_put_int;
265 	} else {
266 		tty_op_ospeed = TTY_OP_OSPEED_PROTO1;
267 		tty_op_ispeed = TTY_OP_ISPEED_PROTO1;
268 		put_arg = (void (*)(Buffer *, u_int)) buffer_put_char;
269 	}
270 
271 	if (tiop == NULL) {
272 		if (fd == -1) {
273 			debug("tty_make_modes: no fd or tio");
274 			goto end;
275 		}
276 		if (tcgetattr(fd, &tio) == -1) {
277 			logit("tcgetattr: %.100s", strerror(errno));
278 			goto end;
279 		}
280 	} else
281 		tio = *tiop;
282 
283 	/* Store input and output baud rates. */
284 	baud = speed_to_baud(cfgetospeed(&tio));
285 	buffer_put_char(&buf, tty_op_ospeed);
286 	buffer_put_int(&buf, baud);
287 	baud = speed_to_baud(cfgetispeed(&tio));
288 	buffer_put_char(&buf, tty_op_ispeed);
289 	buffer_put_int(&buf, baud);
290 
291 	/* Store values of mode flags. */
292 #define TTYCHAR(NAME, OP) \
293 	buffer_put_char(&buf, OP); \
294 	put_arg(&buf, tio.c_cc[NAME]);
295 
296 #define TTYMODE(NAME, FIELD, OP) \
297 	buffer_put_char(&buf, OP); \
298 	put_arg(&buf, ((tio.FIELD & NAME) != 0));
299 
300 #include "ttymodes.h"
301 
302 #undef TTYCHAR
303 #undef TTYMODE
304 
305 end:
306 	/* Mark end of mode data. */
307 	buffer_put_char(&buf, TTY_OP_END);
308 	if (compat20)
309 		packet_put_string(buffer_ptr(&buf), buffer_len(&buf));
310 	else
311 		packet_put_raw(buffer_ptr(&buf), buffer_len(&buf));
312 	buffer_free(&buf);
313 }
314 
315 /*
316  * Decodes terminal modes for the terminal referenced by fd in a portable
317  * manner from a packet being read.
318  */
319 void
320 tty_parse_modes(int fd, int *n_bytes_ptr)
321 {
322 	struct termios tio;
323 	int opcode, baud;
324 	int n_bytes = 0;
325 	int failure = 0;
326 	u_int (*get_arg)(void);
327 	int arg_size;
328 
329 	if (compat20) {
330 		*n_bytes_ptr = packet_get_int();
331 		if (*n_bytes_ptr == 0)
332 			return;
333 		get_arg = packet_get_int;
334 		arg_size = 4;
335 	} else {
336 		get_arg = packet_get_char;
337 		arg_size = 1;
338 	}
339 
340 	/*
341 	 * Get old attributes for the terminal.  We will modify these
342 	 * flags. I am hoping that if there are any machine-specific
343 	 * modes, they will initially have reasonable values.
344 	 */
345 	if (tcgetattr(fd, &tio) == -1) {
346 		logit("tcgetattr: %.100s", strerror(errno));
347 		failure = -1;
348 	}
349 
350 	for (;;) {
351 		n_bytes += 1;
352 		opcode = packet_get_char();
353 		switch (opcode) {
354 		case TTY_OP_END:
355 			goto set;
356 
357 		/* XXX: future conflict possible */
358 		case TTY_OP_ISPEED_PROTO1:
359 		case TTY_OP_ISPEED_PROTO2:
360 			n_bytes += 4;
361 			baud = packet_get_int();
362 			if (failure != -1 &&
363 			    cfsetispeed(&tio, baud_to_speed(baud)) == -1)
364 				error("cfsetispeed failed for %d", baud);
365 			break;
366 
367 		/* XXX: future conflict possible */
368 		case TTY_OP_OSPEED_PROTO1:
369 		case TTY_OP_OSPEED_PROTO2:
370 			n_bytes += 4;
371 			baud = packet_get_int();
372 			if (failure != -1 &&
373 			    cfsetospeed(&tio, baud_to_speed(baud)) == -1)
374 				error("cfsetospeed failed for %d", baud);
375 			break;
376 
377 #define TTYCHAR(NAME, OP) \
378 	case OP: \
379 	  n_bytes += arg_size; \
380 	  tio.c_cc[NAME] = get_arg(); \
381 	  break;
382 #define TTYMODE(NAME, FIELD, OP) \
383 	case OP: \
384 	  n_bytes += arg_size; \
385 	  if (get_arg()) \
386 	    tio.FIELD |= NAME; \
387 	  else \
388 	    tio.FIELD &= ~NAME;	\
389 	  break;
390 
391 #include "ttymodes.h"
392 
393 #undef TTYCHAR
394 #undef TTYMODE
395 
396 		default:
397 			debug("Ignoring unsupported tty mode opcode %d (0x%x)",
398 			    opcode, opcode);
399 			if (!compat20) {
400 				/*
401 				 * SSH1:
402 				 * Opcodes 1 to 127 are defined to have
403 				 * a one-byte argument.
404 				 * Opcodes 128 to 159 are defined to have
405 				 * an integer argument.
406 				 */
407 				if (opcode > 0 && opcode < 128) {
408 					n_bytes += 1;
409 					(void) packet_get_char();
410 					break;
411 				} else if (opcode >= 128 && opcode < 160) {
412 					n_bytes += 4;
413 					(void) packet_get_int();
414 					break;
415 				} else {
416 					/*
417 					 * It is a truly undefined opcode (160 to 255).
418 					 * We have no idea about its arguments.  So we
419 					 * must stop parsing.  Note that some data
420 					 * may be left in the packet; hopefully there
421 					 * is nothing more coming after the mode data.
422 					 */
423 					logit("parse_tty_modes: unknown opcode %d",
424 					    opcode);
425 					goto set;
426 				}
427 			} else {
428 				/*
429 				 * SSH2:
430 				 * Opcodes 1 to 159 are defined to have
431 				 * a uint32 argument.
432 				 * Opcodes 160 to 255 are undefined and
433 				 * cause parsing to stop.
434 				 */
435 				if (opcode > 0 && opcode < 160) {
436 					n_bytes += 4;
437 					(void) packet_get_int();
438 					break;
439 				} else {
440 					logit("parse_tty_modes: unknown opcode %d",
441 					    opcode);
442 					goto set;
443 				}
444 			}
445 		}
446 	}
447 
448 set:
449 	if (*n_bytes_ptr != n_bytes) {
450 		*n_bytes_ptr = n_bytes;
451 		logit("parse_tty_modes: n_bytes_ptr != n_bytes: %d %d",
452 		    *n_bytes_ptr, n_bytes);
453 		return;		/* Don't process bytes passed */
454 	}
455 	if (failure == -1)
456 		return;		/* Packet parsed ok but tcgetattr() failed */
457 
458 	/* Set the new modes for the terminal. */
459 	if (tcsetattr(fd, TCSANOW, &tio) == -1)
460 		logit("Setting tty modes failed: %.100s", strerror(errno));
461 }
462