summaryrefslogtreecommitdiffstats
path: root/ttymodes.c
blob: f0c2a5d37d37348f6f849cd347f786fb9a5ecdbe (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
/* $OpenBSD: ttymodes.c,v 1.34 2018/07/09 21:20:26 markus Exp $ */
/*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 *
 * As far as I am concerned, the code I have written for this software
 * can be used freely for any purpose.  Any derived versions of this
 * software must be clearly marked as such, and if the derived work is
 * incompatible with the protocol description in the RFC file, it must be
 * called by a name other than "ssh" or "Secure Shell".
 */

/*
 * SSH2 tty modes support by Kevin Steves.
 * Copyright (c) 2001 Kevin Steves.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Encoding and decoding of terminal modes in a portable way.
 * Much of the format is defined in ttymodes.h; it is included multiple times
 * into this file with the appropriate macro definitions to generate the
 * suitable code.
 */

#include "includes.h"

#include <sys/types.h>

#include <errno.h>
#include <string.h>
#include <termios.h>
#include <stdarg.h>

#include "packet.h"
#include "log.h"
#include "compat.h"
#include "sshbuf.h"
#include "ssherr.h"

#define TTY_OP_END		0
/*
 * uint32 (u_int) follows speed.
 */
#define TTY_OP_ISPEED	128
#define TTY_OP_OSPEED	129

/*
 * Converts POSIX speed_t to a baud rate.  The values of the
 * constants for speed_t are not themselves portable.
 */
static int
speed_to_baud(speed_t speed)
{
	switch (speed) {
	case B0:
		return 0;
	case B50:
		return 50;
	case B75:
		return 75;
	case B110:
		return 110;
	case B134:
		return 134;
	case B150:
		return 150;
	case B200:
		return 200;
	case B300:
		return 300;
	case B600:
		return 600;
	case B1200:
		return 1200;
	case B1800:
		return 1800;
	case B2400:
		return 2400;
	case B4800:
		return 4800;
	case B9600:
		return 9600;

#ifdef B19200
	case B19200:
		return 19200;
#else /* B19200 */
#ifdef EXTA
	case EXTA:
		return 19200;
#endif /* EXTA */
#endif /* B19200 */

#ifdef B38400
	case B38400:
		return 38400;
#else /* B38400 */
#ifdef EXTB
	case EXTB:
		return 38400;
#endif /* EXTB */
#endif /* B38400 */

#ifdef B7200
	case B7200:
		return 7200;
#endif /* B7200 */
#ifdef B14400
	case B14400:
		return 14400;
#endif /* B14400 */
#ifdef B28800
	case B28800:
		return 28800;
#endif /* B28800 */
#ifdef B57600
	case B57600:
		return 57600;
#endif /* B57600 */
#ifdef B76800
	case B76800:
		return 76800;
#endif /* B76800 */
#ifdef B115200
	case B115200:
		return 115200;
#endif /* B115200 */
#ifdef B230400
	case B230400:
		return 230400;
#endif /* B230400 */
	default:
		return 9600;
	}
}

/*
 * Converts a numeric baud rate to a POSIX speed_t.
 */
static speed_t
baud_to_speed(int baud)
{
	switch (baud) {
	case 0:
		return B0;
	case 50:
		return B50;
	case 75:
		return B75;
	case 110:
		return B110;
	case 134:
		return B134;
	case 150:
		return B150;
	case 200:
		return B200;
	case 300:
		return B300;
	case 600:
		return B600;
	case 1200:
		return B1200;
	case 1800:
		return B1800;
	case 2400:
		return B2400;
	case 4800:
		return B4800;
	case 9600:
		return B9600;

#ifdef B19200
	case 19200:
		return B19200;
#else /* B19200 */
#ifdef EXTA
	case 19200:
		return EXTA;
#endif /* EXTA */
#endif /* B19200 */

#ifdef B38400
	case 38400:
		return B38400;
#else /* B38400 */
#ifdef EXTB
	case 38400:
		return EXTB;
#endif /* EXTB */
#endif /* B38400 */

#ifdef B7200
	case 7200:
		return B7200;
#endif /* B7200 */
#ifdef B14400
	case 14400:
		return B14400;
#endif /* B14400 */
#ifdef B28800
	case 28800:
		return B28800;
#endif /* B28800 */
#ifdef B57600
	case 57600:
		return B57600;
#endif /* B57600 */
#ifdef B76800
	case 76800:
		return B76800;
#endif /* B76800 */
#ifdef B115200
	case 115200:
		return B115200;
#endif /* B115200 */
#ifdef B230400
	case 230400:
		return B230400;
#endif /* B230400 */
	default:
		return B9600;
	}
}

/*
 * Encode a special character into SSH line format.
 */
static u_int
special_char_encode(cc_t c)
{
#ifdef _POSIX_VDISABLE
	if (c == _POSIX_VDISABLE)
		return 255;
#endif /* _POSIX_VDISABLE */
	return c;
}

/*
 * Decode a special character from SSH line format.
 */
static cc_t
special_char_decode(u_int c)
{
#ifdef _POSIX_VDISABLE
	if (c == 255)
		return _POSIX_VDISABLE;
#endif /* _POSIX_VDISABLE */
	return c;
}

/*
 * Encodes terminal modes for the terminal referenced by fd
 * or tiop in a portable manner, and appends the modes to a packet
 * being constructed.
 */
void
ssh_tty_make_modes(struct ssh *ssh, int fd, struct termios *tiop)
{
	struct termios tio;
	struct sshbuf *buf;
	int r, ibaud, obaud;

	if ((buf = sshbuf_new()) == NULL)
		fatal("%s: sshbuf_new failed", __func__);

	if (tiop == NULL) {
		if (fd == -1) {
			debug("%s: no fd or tio", __func__);
			goto end;
		}
		if (tcgetattr(fd, &tio) == -1) {
			logit("tcgetattr: %.100s", strerror(errno));
			goto end;
		}
	} else
		tio = *tiop;

	/* Store input and output baud rates. */
	obaud = speed_to_baud(cfgetospeed(&tio));
	ibaud = speed_to_baud(cfgetispeed(&tio));
	if ((r = sshbuf_put_u8(buf, TTY_OP_OSPEED)) != 0 ||
	    (r = sshbuf_put_u32(buf, obaud)) != 0 ||
	    (r = sshbuf_put_u8(buf, TTY_OP_ISPEED)) != 0 ||
	    (r = sshbuf_put_u32(buf, ibaud)) != 0)
		fatal("%s: buffer error: %s", __func__, ssh_err(r));

	/* Store values of mode flags. */
#define TTYCHAR(NAME, OP) \
	if ((r = sshbuf_put_u8(buf, OP)) != 0 || \
	    (r = sshbuf_put_u32(buf, \
	    special_char_encode(tio.c_cc[NAME]))) != 0) \
		fatal("%s: buffer error: %s", __func__, ssh_err(r)); \

#define SSH_TTYMODE_IUTF8 42  /* for SSH_BUG_UTF8TTYMODE */

#define TTYMODE(NAME, FIELD, OP) \
	if (OP == SSH_TTYMODE_IUTF8 && (datafellows & SSH_BUG_UTF8TTYMODE)) { \
		debug3("%s: SSH_BUG_UTF8TTYMODE", __func__); \
	} else if ((r = sshbuf_put_u8(buf, OP)) != 0 || \
	    (r = sshbuf_put_u32(buf, ((tio.FIELD & NAME) != 0))) != 0) \
		fatal("%s: buffer error: %s", __func__, ssh_err(r)); \

#include "ttymodes.h"

#undef TTYCHAR
#undef TTYMODE

end:
	/* Mark end of mode data. */
	if ((r = sshbuf_put_u8(buf, TTY_OP_END)) != 0 ||
	    (r = sshpkt_put_stringb(ssh, buf)) != 0)
		fatal("%s: packet error: %s", __func__, ssh_err(r));
	sshbuf_free(buf);
}

/*
 * Decodes terminal modes for the terminal referenced by fd in a portable
 * manner from a packet being read.
 */
void
ssh_tty_parse_modes(struct ssh *ssh, int fd)
{
	struct termios tio;
	struct sshbuf *buf;
	const u_char *data;
	u_char opcode;
	u_int baud, u;
	int r, failure = 0;
	size_t len;

	if ((r = sshpkt_get_string_direct(ssh, &data, &len)) != 0)
		fatal("%s: packet error: %s", __func__, ssh_err(r));
	if (len == 0)
		return;
	if ((buf = sshbuf_from(data, len)) == NULL) {
		error("%s: sshbuf_from failed", __func__);
		return;
	}

	/*
	 * Get old attributes for the terminal.  We will modify these
	 * flags. I am hoping that if there are any machine-specific
	 * modes, they will initially have reasonable values.
	 */
	if (tcgetattr(fd, &tio) == -1) {
		logit("tcgetattr: %.100s", strerror(errno));
		failure = -1;
	}

	while (sshbuf_len(buf) > 0) {
		if ((r = sshbuf_get_u8(buf, &opcode)) != 0)
			fatal("%s: packet error: %s", __func__, ssh_err(r));
		switch (opcode) {
		case TTY_OP_END:
			goto set;

		case TTY_OP_ISPEED:
			if ((r = sshbuf_get_u32(buf, &baud)) != 0)
				fatal("%s: packet error: %s",
				    __func__, ssh_err(r));
			if (failure != -1 &&
			    cfsetispeed(&tio, baud_to_speed(baud)) == -1)
				error("cfsetispeed failed for %d", baud);
			break;

		case TTY_OP_OSPEED:
			if ((r = sshbuf_get_u32(buf, &baud)) != 0)
				fatal("%s: packet error: %s",
				    __func__, ssh_err(r));
			if (failure != -1 &&
			    cfsetospeed(&tio, baud_to_speed(baud)) == -1)
				error("cfsetospeed failed for %d", baud);
			break;

#define TTYCHAR(NAME, OP) \
		case OP: \
			if ((r = sshbuf_get_u32(buf, &u)) != 0) \
				fatal("%s: packet error: %s", __func__, \
				    ssh_err(r)); \
			tio.c_cc[NAME] = special_char_decode(u); \
			break;
#define TTYMODE(NAME, FIELD, OP) \
		case OP: \
			if ((r = sshbuf_get_u32(buf, &u)) != 0) \
				fatal("%s: packet error: %s", __func__, \
				    ssh_err(r)); \
			if (u) \
				tio.FIELD |= NAME; \
			else \
				tio.FIELD &= ~NAME; \
			break;

#include "ttymodes.h"

#undef TTYCHAR
#undef TTYMODE

		default:
			debug("Ignoring unsupported tty mode opcode %d (0x%x)",
			    opcode, opcode);
			/*
			 * SSH2:
			 * Opcodes 1 to 159 are defined to have a uint32
			 * argument.
			 * Opcodes 160 to 255 are undefined and cause parsing
			 * to stop.
			 */
			if (opcode > 0 && opcode < 160) {
				if ((r = sshbuf_get_u32(buf, NULL)) != 0)
					fatal("%s: packet error: %s", __func__,
					    ssh_err(r));
				break;
			} else {
				logit("%s: unknown opcode %d", __func__,
				    opcode);
				goto set;
			}
		}
	}

set:
	len = sshbuf_len(buf);
	sshbuf_free(buf);
	if (len > 0) {
		logit("%s: %zu bytes left", __func__, len);
		return;		/* Don't process bytes passed */
	}
	if (failure == -1)
		return;		/* Packet parsed ok but tcgetattr() failed */

	/* Set the new modes for the terminal. */
	if (tcsetattr(fd, TCSANOW, &tio) == -1)
		logit("Setting tty modes failed: %.100s", strerror(errno));
}