1 /* $OpenBSD: ttymodes.c,v 1.36 2021/01/27 09:26:54 djm 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 "sshbuf.h"
57 #include "ssherr.h"
58
59 #define TTY_OP_END 0
60 /*
61 * uint32 (u_int) follows speed.
62 */
63 #define TTY_OP_ISPEED 128
64 #define TTY_OP_OSPEED 129
65
66 /*
67 * Converts POSIX speed_t to a baud rate. The values of the
68 * constants for speed_t are not themselves portable.
69 */
70 static int
speed_to_baud(speed_t speed)71 speed_to_baud(speed_t speed)
72 {
73 switch (speed) {
74 case B0:
75 return 0;
76 case B50:
77 return 50;
78 case B75:
79 return 75;
80 case B110:
81 return 110;
82 case B134:
83 return 134;
84 case B150:
85 return 150;
86 case B200:
87 return 200;
88 case B300:
89 return 300;
90 case B600:
91 return 600;
92 case B1200:
93 return 1200;
94 case B1800:
95 return 1800;
96 case B2400:
97 return 2400;
98 case B4800:
99 return 4800;
100 case B9600:
101 return 9600;
102
103 #ifdef B19200
104 case B19200:
105 return 19200;
106 #else /* B19200 */
107 #ifdef EXTA
108 case EXTA:
109 return 19200;
110 #endif /* EXTA */
111 #endif /* B19200 */
112
113 #ifdef B38400
114 case B38400:
115 return 38400;
116 #else /* B38400 */
117 #ifdef EXTB
118 case EXTB:
119 return 38400;
120 #endif /* EXTB */
121 #endif /* B38400 */
122
123 #ifdef B7200
124 case B7200:
125 return 7200;
126 #endif /* B7200 */
127 #ifdef B14400
128 case B14400:
129 return 14400;
130 #endif /* B14400 */
131 #ifdef B28800
132 case B28800:
133 return 28800;
134 #endif /* B28800 */
135 #ifdef B57600
136 case B57600:
137 return 57600;
138 #endif /* B57600 */
139 #ifdef B76800
140 case B76800:
141 return 76800;
142 #endif /* B76800 */
143 #ifdef B115200
144 case B115200:
145 return 115200;
146 #endif /* B115200 */
147 #ifdef B230400
148 case B230400:
149 return 230400;
150 #endif /* B230400 */
151 default:
152 return 9600;
153 }
154 }
155
156 /*
157 * Converts a numeric baud rate to a POSIX speed_t.
158 */
159 static speed_t
baud_to_speed(int baud)160 baud_to_speed(int baud)
161 {
162 switch (baud) {
163 case 0:
164 return B0;
165 case 50:
166 return B50;
167 case 75:
168 return B75;
169 case 110:
170 return B110;
171 case 134:
172 return B134;
173 case 150:
174 return B150;
175 case 200:
176 return B200;
177 case 300:
178 return B300;
179 case 600:
180 return B600;
181 case 1200:
182 return B1200;
183 case 1800:
184 return B1800;
185 case 2400:
186 return B2400;
187 case 4800:
188 return B4800;
189 case 9600:
190 return B9600;
191
192 #ifdef B19200
193 case 19200:
194 return B19200;
195 #else /* B19200 */
196 #ifdef EXTA
197 case 19200:
198 return EXTA;
199 #endif /* EXTA */
200 #endif /* B19200 */
201
202 #ifdef B38400
203 case 38400:
204 return B38400;
205 #else /* B38400 */
206 #ifdef EXTB
207 case 38400:
208 return EXTB;
209 #endif /* EXTB */
210 #endif /* B38400 */
211
212 #ifdef B7200
213 case 7200:
214 return B7200;
215 #endif /* B7200 */
216 #ifdef B14400
217 case 14400:
218 return B14400;
219 #endif /* B14400 */
220 #ifdef B28800
221 case 28800:
222 return B28800;
223 #endif /* B28800 */
224 #ifdef B57600
225 case 57600:
226 return B57600;
227 #endif /* B57600 */
228 #ifdef B76800
229 case 76800:
230 return B76800;
231 #endif /* B76800 */
232 #ifdef B115200
233 case 115200:
234 return B115200;
235 #endif /* B115200 */
236 #ifdef B230400
237 case 230400:
238 return B230400;
239 #endif /* B230400 */
240 default:
241 return B9600;
242 }
243 }
244
245 /*
246 * Encodes terminal modes for the terminal referenced by fd
247 * or tiop in a portable manner, and appends the modes to a packet
248 * being constructed.
249 */
250 void
ssh_tty_make_modes(struct ssh * ssh,int fd,struct termios * tiop)251 ssh_tty_make_modes(struct ssh *ssh, int fd, struct termios *tiop)
252 {
253 struct termios tio;
254 struct sshbuf *buf;
255 int r, ibaud, obaud;
256
257 if ((buf = sshbuf_new()) == NULL)
258 fatal_f("sshbuf_new failed");
259
260 if (tiop == NULL) {
261 if (fd == -1) {
262 debug_f("no fd or tio");
263 goto end;
264 }
265 if (tcgetattr(fd, &tio) == -1) {
266 logit("tcgetattr: %.100s", strerror(errno));
267 goto end;
268 }
269 } else
270 tio = *tiop;
271
272 /* Store input and output baud rates. */
273 obaud = speed_to_baud(cfgetospeed(&tio));
274 ibaud = speed_to_baud(cfgetispeed(&tio));
275 if ((r = sshbuf_put_u8(buf, TTY_OP_OSPEED)) != 0 ||
276 (r = sshbuf_put_u32(buf, obaud)) != 0 ||
277 (r = sshbuf_put_u8(buf, TTY_OP_ISPEED)) != 0 ||
278 (r = sshbuf_put_u32(buf, ibaud)) != 0)
279 fatal_fr(r, "compose");
280
281 /* Store values of mode flags. */
282 #define TTYCHAR(NAME, OP) \
283 if ((r = sshbuf_put_u8(buf, OP)) != 0 || \
284 (r = sshbuf_put_u32(buf, tio.c_cc[NAME])) != 0) \
285 fatal_fr(r, "compose %s", #NAME);
286
287 #define SSH_TTYMODE_IUTF8 42 /* for SSH_BUG_UTF8TTYMODE */
288
289 #define TTYMODE(NAME, FIELD, OP) \
290 if (OP == SSH_TTYMODE_IUTF8 && (ssh->compat & SSH_BUG_UTF8TTYMODE)) { \
291 debug3_f("SSH_BUG_UTF8TTYMODE"); \
292 } else if ((r = sshbuf_put_u8(buf, OP)) != 0 || \
293 (r = sshbuf_put_u32(buf, ((tio.FIELD & NAME) != 0))) != 0) \
294 fatal_fr(r, "compose %s", #NAME);
295
296 #include "ttymodes.h"
297
298 #undef TTYCHAR
299 #undef TTYMODE
300
301 end:
302 /* Mark end of mode data. */
303 if ((r = sshbuf_put_u8(buf, TTY_OP_END)) != 0 ||
304 (r = sshpkt_put_stringb(ssh, buf)) != 0)
305 fatal_fr(r, "compose end");
306 sshbuf_free(buf);
307 }
308
309 /*
310 * Decodes terminal modes for the terminal referenced by fd in a portable
311 * manner from a packet being read.
312 */
313 void
ssh_tty_parse_modes(struct ssh * ssh,int fd)314 ssh_tty_parse_modes(struct ssh *ssh, int fd)
315 {
316 struct termios tio;
317 struct sshbuf *buf;
318 const u_char *data;
319 u_char opcode;
320 u_int baud, u;
321 int r, failure = 0;
322 size_t len;
323
324 if ((r = sshpkt_get_string_direct(ssh, &data, &len)) != 0)
325 fatal_fr(r, "parse");
326 if (len == 0)
327 return;
328 if ((buf = sshbuf_from(data, len)) == NULL) {
329 error_f("sshbuf_from failed");
330 return;
331 }
332
333 /*
334 * Get old attributes for the terminal. We will modify these
335 * flags. I am hoping that if there are any machine-specific
336 * modes, they will initially have reasonable values.
337 */
338 if (tcgetattr(fd, &tio) == -1) {
339 logit("tcgetattr: %.100s", strerror(errno));
340 failure = -1;
341 }
342
343 while (sshbuf_len(buf) > 0) {
344 if ((r = sshbuf_get_u8(buf, &opcode)) != 0)
345 fatal_fr(r, "parse opcode");
346 switch (opcode) {
347 case TTY_OP_END:
348 goto set;
349
350 case TTY_OP_ISPEED:
351 if ((r = sshbuf_get_u32(buf, &baud)) != 0)
352 fatal_fr(r, "parse ispeed");
353 if (failure != -1 &&
354 cfsetispeed(&tio, baud_to_speed(baud)) == -1)
355 error("cfsetispeed failed for %d", baud);
356 break;
357
358 case TTY_OP_OSPEED:
359 if ((r = sshbuf_get_u32(buf, &baud)) != 0)
360 fatal_fr(r, "parse ospeed");
361 if (failure != -1 &&
362 cfsetospeed(&tio, baud_to_speed(baud)) == -1)
363 error("cfsetospeed failed for %d", baud);
364 break;
365
366 #define TTYCHAR(NAME, OP) \
367 case OP: \
368 if ((r = sshbuf_get_u32(buf, &u)) != 0) \
369 fatal_fr(r, "parse %s", #NAME); \
370 tio.c_cc[NAME] = u; \
371 break;
372 #define TTYMODE(NAME, FIELD, OP) \
373 case OP: \
374 if ((r = sshbuf_get_u32(buf, &u)) != 0) \
375 fatal_fr(r, "parse %s", #NAME); \
376 if (u) \
377 tio.FIELD |= NAME; \
378 else \
379 tio.FIELD &= ~NAME; \
380 break;
381
382 #include "ttymodes.h"
383
384 #undef TTYCHAR
385 #undef TTYMODE
386
387 default:
388 debug("Ignoring unsupported tty mode opcode %d (0x%x)",
389 opcode, opcode);
390 /*
391 * SSH2:
392 * Opcodes 1 to 159 are defined to have a uint32
393 * argument.
394 * Opcodes 160 to 255 are undefined and cause parsing
395 * to stop.
396 */
397 if (opcode > 0 && opcode < 160) {
398 if ((r = sshbuf_get_u32(buf, NULL)) != 0)
399 fatal_fr(r, "parse arg");
400 break;
401 } else {
402 logit_f("unknown opcode %d", opcode);
403 goto set;
404 }
405 }
406 }
407
408 set:
409 len = sshbuf_len(buf);
410 sshbuf_free(buf);
411 if (len > 0) {
412 logit_f("%zu bytes left", len);
413 return; /* Don't process bytes passed */
414 }
415 if (failure == -1)
416 return; /* Packet parsed ok but tcgetattr() failed */
417
418 /* Set the new modes for the terminal. */
419 if (tcsetattr(fd, TCSANOW, &tio) == -1)
420 logit("Setting tty modes failed: %.100s", strerror(errno));
421 }
422