1 /*
2 * Dropbear SSH
3 *
4 * Copyright (c) 2002,2003 Matt Johnston
5 * Copyright (c) 2004 by Mihnea Stoenescu
6 * All rights reserved.
7 *
8 * Permission is hereby granted, free of charge, to any person obtaining a copy
9 * of this software and associated documentation files (the "Software"), to deal
10 * in the Software without restriction, including without limitation the rights
11 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12 * copies of the Software, and to permit persons to whom the Software is
13 * furnished to do so, subject to the following conditions:
14 *
15 * The above copyright notice and this permission notice shall be included in
16 * all copies or substantial portions of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
24 * SOFTWARE. */
25
26 #include "includes.h"
27 #include "packet.h"
28 #include "buffer.h"
29 #include "session.h"
30 #include "dbutil.h"
31 #include "channel.h"
32 #include "ssh.h"
33 #include "runopts.h"
34 #include "termcodes.h"
35 #include "chansession.h"
36
37 static void cli_closechansess(struct Channel *channel);
38 static int cli_initchansess(struct Channel *channel);
39 static void cli_chansessreq(struct Channel *channel);
40
41 static void start_channel_request(struct Channel *channel, unsigned char *type);
42
43 static void send_chansess_pty_req(struct Channel *channel);
44 static void send_chansess_shell_req(struct Channel *channel);
45
46 static void cli_tty_setup();
47
48 const struct ChanType clichansess = {
49 0, /* sepfds */
50 "session", /* name */
51 cli_initchansess, /* inithandler */
52 NULL, /* checkclosehandler */
53 cli_chansessreq, /* reqhandler */
54 cli_closechansess, /* closehandler */
55 };
56
cli_chansessreq(struct Channel * channel)57 static void cli_chansessreq(struct Channel *channel) {
58
59 unsigned char* type = NULL;
60 int wantreply;
61
62 TRACE(("enter cli_chansessreq"))
63
64 type = buf_getstring(ses.payload, NULL);
65 wantreply = buf_getbool(ses.payload);
66
67 if (strcmp(type, "exit-status") == 0) {
68 cli_ses.retval = buf_getint(ses.payload);
69 TRACE(("got exit-status of '%d'", cli_ses.retval))
70 } else if (strcmp(type, "exit-signal") == 0) {
71 TRACE(("got exit-signal, ignoring it"))
72 } else {
73 TRACE(("unknown request '%s'", type))
74 send_msg_channel_failure(channel);
75 goto out;
76 }
77
78 out:
79 m_free(type);
80 }
81
82
83 /* If the main session goes, we close it up */
cli_closechansess(struct Channel * UNUSED (channel))84 static void cli_closechansess(struct Channel *UNUSED(channel)) {
85
86 /* This channel hasn't gone yet, so we have > 1 */
87 if (ses.chancount > 1) {
88 dropbear_log(LOG_INFO, "Waiting for other channels to close...");
89 }
90
91 cli_tty_cleanup(); /* Restore tty modes etc */
92
93 }
94
start_channel_request(struct Channel * channel,unsigned char * type)95 static void start_channel_request(struct Channel *channel,
96 unsigned char *type) {
97
98 CHECKCLEARTOWRITE();
99 buf_putbyte(ses.writepayload, SSH_MSG_CHANNEL_REQUEST);
100 buf_putint(ses.writepayload, channel->remotechan);
101
102 buf_putstring(ses.writepayload, type, strlen(type));
103
104 }
105
106 /* Taken from OpenSSH's sshtty.c:
107 * RCSID("OpenBSD: sshtty.c,v 1.5 2003/09/19 17:43:35 markus Exp "); */
cli_tty_setup()108 static void cli_tty_setup() {
109
110 struct termios tio;
111
112 TRACE(("enter cli_pty_setup"))
113
114 if (cli_ses.tty_raw_mode == 1) {
115 TRACE(("leave cli_tty_setup: already in raw mode!"))
116 return;
117 }
118
119 if (tcgetattr(STDIN_FILENO, &tio) == -1) {
120 dropbear_exit("Failed to set raw TTY mode");
121 }
122
123 /* make a copy */
124 cli_ses.saved_tio = tio;
125
126 tio.c_iflag |= IGNPAR;
127 tio.c_iflag &= ~(ISTRIP | INLCR | IGNCR | ICRNL | IXON | IXANY | IXOFF);
128 #ifdef IUCLC
129 tio.c_iflag &= ~IUCLC;
130 #endif
131 tio.c_lflag &= ~(ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHONL);
132 #ifdef IEXTEN
133 tio.c_lflag &= ~IEXTEN;
134 #endif
135 tio.c_oflag &= ~OPOST;
136 tio.c_cc[VMIN] = 1;
137 tio.c_cc[VTIME] = 0;
138 if (tcsetattr(STDIN_FILENO, TCSADRAIN, &tio) == -1) {
139 dropbear_exit("Failed to set raw TTY mode");
140 }
141
142 cli_ses.tty_raw_mode = 1;
143 TRACE(("leave cli_tty_setup"))
144 }
145
cli_tty_cleanup()146 void cli_tty_cleanup() {
147
148 TRACE(("enter cli_tty_cleanup"))
149
150 if (cli_ses.tty_raw_mode == 0) {
151 TRACE(("leave cli_tty_cleanup: not in raw mode"))
152 return;
153 }
154
155 if (tcsetattr(STDIN_FILENO, TCSADRAIN, &cli_ses.saved_tio) == -1) {
156 dropbear_log(LOG_WARNING, "Failed restoring TTY");
157 } else {
158 cli_ses.tty_raw_mode = 0;
159 }
160
161 TRACE(("leave cli_tty_cleanup"))
162 }
163
put_termcodes()164 static void put_termcodes() {
165
166 struct termios tio;
167 unsigned int sshcode;
168 const struct TermCode *termcode;
169 unsigned int value;
170 unsigned int mapcode;
171
172 unsigned int bufpos1, bufpos2;
173
174 TRACE(("enter put_termcodes"))
175
176 if (tcgetattr(STDIN_FILENO, &tio) == -1) {
177 dropbear_log(LOG_WARNING, "Failed reading termmodes");
178 buf_putint(ses.writepayload, 1); /* Just the terminator */
179 buf_putbyte(ses.writepayload, 0); /* TTY_OP_END */
180 return;
181 }
182
183 bufpos1 = ses.writepayload->pos;
184 buf_putint(ses.writepayload, 0); /* A placeholder for the final length */
185
186 /* As with Dropbear server, we ignore baud rates for now */
187 for (sshcode = 1; sshcode < MAX_TERMCODE; sshcode++) {
188
189 termcode = &termcodes[sshcode];
190 mapcode = termcode->mapcode;
191
192 switch (termcode->type) {
193
194 case TERMCODE_NONE:
195 continue;
196
197 case TERMCODE_CONTROLCHAR:
198 value = tio.c_cc[mapcode];
199 break;
200
201 case TERMCODE_INPUT:
202 value = tio.c_iflag & mapcode;
203 break;
204
205 case TERMCODE_OUTPUT:
206 value = tio.c_oflag & mapcode;
207 break;
208
209 case TERMCODE_LOCAL:
210 value = tio.c_lflag & mapcode;
211 break;
212
213 case TERMCODE_CONTROL:
214 value = tio.c_cflag & mapcode;
215 break;
216
217 default:
218 continue;
219
220 }
221
222 /* If we reach here, we have something to say */
223 buf_putbyte(ses.writepayload, sshcode);
224 buf_putint(ses.writepayload, value);
225 }
226
227 buf_putbyte(ses.writepayload, 0); /* THE END, aka TTY_OP_END */
228
229 /* Put the string length at the start of the buffer */
230 bufpos2 = ses.writepayload->pos;
231
232 buf_setpos(ses.writepayload, bufpos1); /* Jump back */
233 buf_putint(ses.writepayload, bufpos2 - bufpos1 - 4); /* len(termcodes) */
234 buf_setpos(ses.writepayload, bufpos2); /* Back where we were */
235
236 TRACE(("leave put_termcodes"))
237 }
238
put_winsize()239 static void put_winsize() {
240
241 struct winsize ws;
242
243 if (ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) < 0) {
244 /* Some sane defaults */
245 ws.ws_row = 25;
246 ws.ws_col = 80;
247 ws.ws_xpixel = 0;
248 ws.ws_ypixel = 0;
249 }
250
251 buf_putint(ses.writepayload, ws.ws_col); /* Cols */
252 buf_putint(ses.writepayload, ws.ws_row); /* Rows */
253 buf_putint(ses.writepayload, ws.ws_xpixel); /* Width */
254 buf_putint(ses.writepayload, ws.ws_ypixel); /* Height */
255
256 }
257
sigwinch_handler(int UNUSED (unused))258 static void sigwinch_handler(int UNUSED(unused)) {
259
260 cli_ses.winchange = 1;
261
262 }
263
cli_chansess_winchange()264 void cli_chansess_winchange() {
265
266 unsigned int i;
267 struct Channel *channel = NULL;
268
269 for (i = 0; i < ses.chansize; i++) {
270 channel = ses.channels[i];
271 if (channel != NULL && channel->type == &clichansess) {
272 CHECKCLEARTOWRITE();
273 buf_putbyte(ses.writepayload, SSH_MSG_CHANNEL_REQUEST);
274 buf_putint(ses.writepayload, channel->remotechan);
275 buf_putstring(ses.writepayload, "window-change", 13);
276 buf_putbyte(ses.writepayload, 0); /* FALSE says the spec */
277 put_winsize();
278 encrypt_packet();
279 }
280 }
281 cli_ses.winchange = 0;
282 }
283
send_chansess_pty_req(struct Channel * channel)284 static void send_chansess_pty_req(struct Channel *channel) {
285
286 unsigned char* term = NULL;
287
288 TRACE(("enter send_chansess_pty_req"))
289
290 start_channel_request(channel, "pty-req");
291
292 /* Don't want replies */
293 buf_putbyte(ses.writepayload, 0);
294
295 /* Get the terminal */
296 term = getenv("TERM");
297 if (term == NULL) {
298 term = "vt100"; /* Seems a safe default */
299 }
300 buf_putstring(ses.writepayload, term, strlen(term));
301
302 /* Window size */
303 put_winsize();
304
305 /* Terminal mode encoding */
306 put_termcodes();
307
308 encrypt_packet();
309
310 /* Set up a window-change handler */
311 if (signal(SIGWINCH, sigwinch_handler) == SIG_ERR) {
312 dropbear_exit("signal error");
313 }
314 TRACE(("leave send_chansess_pty_req"))
315 }
316
send_chansess_shell_req(struct Channel * channel)317 static void send_chansess_shell_req(struct Channel *channel) {
318
319 unsigned char* reqtype = NULL;
320
321 TRACE(("enter send_chansess_shell_req"))
322
323 if (cli_opts.cmd) {
324 reqtype = "exec";
325 } else {
326 reqtype = "shell";
327 }
328
329 start_channel_request(channel, reqtype);
330
331 /* XXX TODO */
332 buf_putbyte(ses.writepayload, 0); /* Don't want replies */
333 if (cli_opts.cmd) {
334 buf_putstring(ses.writepayload, cli_opts.cmd, strlen(cli_opts.cmd));
335 }
336
337 encrypt_packet();
338 TRACE(("leave send_chansess_shell_req"))
339 }
340
cli_initchansess(struct Channel * channel)341 static int cli_initchansess(struct Channel *channel) {
342
343
344 channel->writefd = STDOUT_FILENO;
345 setnonblocking(STDOUT_FILENO);
346
347 channel->readfd = STDIN_FILENO;
348 setnonblocking(STDIN_FILENO);
349
350 channel->errfd = STDERR_FILENO;
351 setnonblocking(STDERR_FILENO);
352
353 channel->extrabuf = cbuf_new(RECV_MAXWINDOW);
354
355 if (cli_opts.wantpty) {
356 send_chansess_pty_req(channel);
357 }
358
359 send_chansess_shell_req(channel);
360
361 if (cli_opts.wantpty) {
362 cli_tty_setup();
363 }
364
365 return 0; /* Success */
366
367 }
368
cli_send_chansess_request()369 void cli_send_chansess_request() {
370
371 TRACE(("enter cli_send_chansess_request"))
372 if (send_msg_channel_open_init(STDIN_FILENO, &clichansess)
373 == DROPBEAR_FAILURE) {
374 dropbear_exit("Couldn't open initial channel");
375 }
376
377 /* No special channel request data */
378 encrypt_packet();
379 TRACE(("leave cli_send_chansess_request"))
380
381 }
382