1 |
|
|
/* $OpenBSD: nchan.c,v 1.67 2017/09/12 06:35:32 djm Exp $ */ |
2 |
|
|
/* |
3 |
|
|
* Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. |
4 |
|
|
* |
5 |
|
|
* Redistribution and use in source and binary forms, with or without |
6 |
|
|
* modification, are permitted provided that the following conditions |
7 |
|
|
* are met: |
8 |
|
|
* 1. Redistributions of source code must retain the above copyright |
9 |
|
|
* notice, this list of conditions and the following disclaimer. |
10 |
|
|
* 2. Redistributions in binary form must reproduce the above copyright |
11 |
|
|
* notice, this list of conditions and the following disclaimer in the |
12 |
|
|
* documentation and/or other materials provided with the distribution. |
13 |
|
|
* |
14 |
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
15 |
|
|
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
16 |
|
|
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
17 |
|
|
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
18 |
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
19 |
|
|
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
20 |
|
|
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
21 |
|
|
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
22 |
|
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
23 |
|
|
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
24 |
|
|
*/ |
25 |
|
|
|
26 |
|
|
#include <sys/types.h> |
27 |
|
|
#include <sys/socket.h> |
28 |
|
|
#include <sys/queue.h> |
29 |
|
|
|
30 |
|
|
#include <errno.h> |
31 |
|
|
#include <string.h> |
32 |
|
|
#include <stdarg.h> |
33 |
|
|
|
34 |
|
|
#include "ssh2.h" |
35 |
|
|
#include "sshbuf.h" |
36 |
|
|
#include "ssherr.h" |
37 |
|
|
#include "packet.h" |
38 |
|
|
#include "channels.h" |
39 |
|
|
#include "compat.h" |
40 |
|
|
#include "log.h" |
41 |
|
|
|
42 |
|
|
/* |
43 |
|
|
* SSH Protocol 1.5 aka New Channel Protocol |
44 |
|
|
* Thanks to Martina, Axel and everyone who left Erlangen, leaving me bored. |
45 |
|
|
* Written by Markus Friedl in October 1999 |
46 |
|
|
* |
47 |
|
|
* Protocol versions 1.3 and 1.5 differ in the handshake protocol used for the |
48 |
|
|
* tear down of channels: |
49 |
|
|
* |
50 |
|
|
* 1.3: strict request-ack-protocol: |
51 |
|
|
* CLOSE -> |
52 |
|
|
* <- CLOSE_CONFIRM |
53 |
|
|
* |
54 |
|
|
* 1.5: uses variations of: |
55 |
|
|
* IEOF -> |
56 |
|
|
* <- OCLOSE |
57 |
|
|
* <- IEOF |
58 |
|
|
* OCLOSE -> |
59 |
|
|
* i.e. both sides have to close the channel |
60 |
|
|
* |
61 |
|
|
* 2.0: the EOF messages are optional |
62 |
|
|
* |
63 |
|
|
* See the debugging output from 'ssh -v' and 'sshd -d' of |
64 |
|
|
* ssh-1.2.27 as an example. |
65 |
|
|
* |
66 |
|
|
*/ |
67 |
|
|
|
68 |
|
|
/* functions manipulating channel states */ |
69 |
|
|
/* |
70 |
|
|
* EVENTS update channel input/output states execute ACTIONS |
71 |
|
|
*/ |
72 |
|
|
/* |
73 |
|
|
* ACTIONS: should never update the channel states |
74 |
|
|
*/ |
75 |
|
|
static void chan_send_eof2(struct ssh *, Channel *); |
76 |
|
|
static void chan_send_eow2(struct ssh *, Channel *); |
77 |
|
|
|
78 |
|
|
/* helper */ |
79 |
|
|
static void chan_shutdown_write(struct ssh *, Channel *); |
80 |
|
|
static void chan_shutdown_read(struct ssh *, Channel *); |
81 |
|
|
|
82 |
|
|
static const char *ostates[] = { "open", "drain", "wait_ieof", "closed" }; |
83 |
|
|
static const char *istates[] = { "open", "drain", "wait_oclose", "closed" }; |
84 |
|
|
|
85 |
|
|
static void |
86 |
|
|
chan_set_istate(Channel *c, u_int next) |
87 |
|
|
{ |
88 |
|
|
if (c->istate > CHAN_INPUT_CLOSED || next > CHAN_INPUT_CLOSED) |
89 |
|
|
fatal("chan_set_istate: bad state %d -> %d", c->istate, next); |
90 |
|
|
debug2("channel %d: input %s -> %s", c->self, istates[c->istate], |
91 |
|
|
istates[next]); |
92 |
|
|
c->istate = next; |
93 |
|
|
} |
94 |
|
|
|
95 |
|
|
static void |
96 |
|
|
chan_set_ostate(Channel *c, u_int next) |
97 |
|
|
{ |
98 |
|
|
if (c->ostate > CHAN_OUTPUT_CLOSED || next > CHAN_OUTPUT_CLOSED) |
99 |
|
|
fatal("chan_set_ostate: bad state %d -> %d", c->ostate, next); |
100 |
|
|
debug2("channel %d: output %s -> %s", c->self, ostates[c->ostate], |
101 |
|
|
ostates[next]); |
102 |
|
|
c->ostate = next; |
103 |
|
|
} |
104 |
|
|
|
105 |
|
|
void |
106 |
|
|
chan_read_failed(struct ssh *ssh, Channel *c) |
107 |
|
|
{ |
108 |
|
|
debug2("channel %d: read failed", c->self); |
109 |
|
|
switch (c->istate) { |
110 |
|
|
case CHAN_INPUT_OPEN: |
111 |
|
|
chan_shutdown_read(ssh, c); |
112 |
|
|
chan_set_istate(c, CHAN_INPUT_WAIT_DRAIN); |
113 |
|
|
break; |
114 |
|
|
default: |
115 |
|
|
error("channel %d: chan_read_failed for istate %d", |
116 |
|
|
c->self, c->istate); |
117 |
|
|
break; |
118 |
|
|
} |
119 |
|
|
} |
120 |
|
|
|
121 |
|
|
void |
122 |
|
|
chan_ibuf_empty(struct ssh *ssh, Channel *c) |
123 |
|
|
{ |
124 |
|
|
debug2("channel %d: ibuf empty", c->self); |
125 |
|
|
if (sshbuf_len(c->input)) { |
126 |
|
|
error("channel %d: chan_ibuf_empty for non empty buffer", |
127 |
|
|
c->self); |
128 |
|
|
return; |
129 |
|
|
} |
130 |
|
|
switch (c->istate) { |
131 |
|
|
case CHAN_INPUT_WAIT_DRAIN: |
132 |
|
|
if (!(c->flags & (CHAN_CLOSE_SENT|CHAN_LOCAL))) |
133 |
|
|
chan_send_eof2(ssh, c); |
134 |
|
|
chan_set_istate(c, CHAN_INPUT_CLOSED); |
135 |
|
|
break; |
136 |
|
|
default: |
137 |
|
|
error("channel %d: chan_ibuf_empty for istate %d", |
138 |
|
|
c->self, c->istate); |
139 |
|
|
break; |
140 |
|
|
} |
141 |
|
|
} |
142 |
|
|
|
143 |
|
|
void |
144 |
|
|
chan_obuf_empty(struct ssh *ssh, Channel *c) |
145 |
|
|
{ |
146 |
|
|
debug2("channel %d: obuf empty", c->self); |
147 |
|
|
if (sshbuf_len(c->output)) { |
148 |
|
|
error("channel %d: chan_obuf_empty for non empty buffer", |
149 |
|
|
c->self); |
150 |
|
|
return; |
151 |
|
|
} |
152 |
|
|
switch (c->ostate) { |
153 |
|
|
case CHAN_OUTPUT_WAIT_DRAIN: |
154 |
|
|
chan_shutdown_write(ssh, c); |
155 |
|
|
chan_set_ostate(c, CHAN_OUTPUT_CLOSED); |
156 |
|
|
break; |
157 |
|
|
default: |
158 |
|
|
error("channel %d: internal error: obuf_empty for ostate %d", |
159 |
|
|
c->self, c->ostate); |
160 |
|
|
break; |
161 |
|
|
} |
162 |
|
|
} |
163 |
|
|
|
164 |
|
|
void |
165 |
|
|
chan_rcvd_eow(struct ssh *ssh, Channel *c) |
166 |
|
|
{ |
167 |
|
|
debug2("channel %d: rcvd eow", c->self); |
168 |
|
|
switch (c->istate) { |
169 |
|
|
case CHAN_INPUT_OPEN: |
170 |
|
|
chan_shutdown_read(ssh, c); |
171 |
|
|
chan_set_istate(c, CHAN_INPUT_CLOSED); |
172 |
|
|
break; |
173 |
|
|
} |
174 |
|
|
} |
175 |
|
|
|
176 |
|
|
static void |
177 |
|
|
chan_send_eof2(struct ssh *ssh, Channel *c) |
178 |
|
|
{ |
179 |
|
|
int r; |
180 |
|
|
|
181 |
|
|
debug2("channel %d: send eof", c->self); |
182 |
|
|
switch (c->istate) { |
183 |
|
|
case CHAN_INPUT_WAIT_DRAIN: |
184 |
|
|
if (!c->have_remote_id) |
185 |
|
|
fatal("%s: channel %d: no remote_id", |
186 |
|
|
__func__, c->self); |
187 |
|
|
if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EOF)) != 0 || |
188 |
|
|
(r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || |
189 |
|
|
(r = sshpkt_send(ssh)) != 0) |
190 |
|
|
fatal("%s: send CHANNEL_EOF: %s", __func__, ssh_err(r)); |
191 |
|
|
c->flags |= CHAN_EOF_SENT; |
192 |
|
|
break; |
193 |
|
|
default: |
194 |
|
|
error("channel %d: cannot send eof for istate %d", |
195 |
|
|
c->self, c->istate); |
196 |
|
|
break; |
197 |
|
|
} |
198 |
|
|
} |
199 |
|
|
|
200 |
|
|
static void |
201 |
|
|
chan_send_close2(struct ssh *ssh, Channel *c) |
202 |
|
|
{ |
203 |
|
|
int r; |
204 |
|
|
|
205 |
|
|
debug2("channel %d: send close", c->self); |
206 |
|
|
if (c->ostate != CHAN_OUTPUT_CLOSED || |
207 |
|
|
c->istate != CHAN_INPUT_CLOSED) { |
208 |
|
|
error("channel %d: cannot send close for istate/ostate %d/%d", |
209 |
|
|
c->self, c->istate, c->ostate); |
210 |
|
|
} else if (c->flags & CHAN_CLOSE_SENT) { |
211 |
|
|
error("channel %d: already sent close", c->self); |
212 |
|
|
} else { |
213 |
|
|
if (!c->have_remote_id) |
214 |
|
|
fatal("%s: channel %d: no remote_id", |
215 |
|
|
__func__, c->self); |
216 |
|
|
if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_CLOSE)) != 0 || |
217 |
|
|
(r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || |
218 |
|
|
(r = sshpkt_send(ssh)) != 0) |
219 |
|
|
fatal("%s: send CHANNEL_EOF: %s", __func__, ssh_err(r)); |
220 |
|
|
c->flags |= CHAN_CLOSE_SENT; |
221 |
|
|
} |
222 |
|
|
} |
223 |
|
|
|
224 |
|
|
static void |
225 |
|
|
chan_send_eow2(struct ssh *ssh, Channel *c) |
226 |
|
|
{ |
227 |
|
|
int r; |
228 |
|
|
|
229 |
|
|
debug2("channel %d: send eow", c->self); |
230 |
|
|
if (c->ostate == CHAN_OUTPUT_CLOSED) { |
231 |
|
|
error("channel %d: must not sent eow on closed output", |
232 |
|
|
c->self); |
233 |
|
|
return; |
234 |
|
|
} |
235 |
|
|
if (!(datafellows & SSH_NEW_OPENSSH)) |
236 |
|
|
return; |
237 |
|
|
if (!c->have_remote_id) |
238 |
|
|
fatal("%s: channel %d: no remote_id", __func__, c->self); |
239 |
|
|
if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 || |
240 |
|
|
(r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || |
241 |
|
|
(r = sshpkt_put_cstring(ssh, "eow@openssh.com")) != 0 || |
242 |
|
|
(r = sshpkt_put_u8(ssh, 0)) != 0 || |
243 |
|
|
(r = sshpkt_send(ssh)) != 0) |
244 |
|
|
fatal("%s: send CHANNEL_EOF: %s", __func__, ssh_err(r)); |
245 |
|
|
} |
246 |
|
|
|
247 |
|
|
/* shared */ |
248 |
|
|
|
249 |
|
|
void |
250 |
|
|
chan_rcvd_ieof(struct ssh *ssh, Channel *c) |
251 |
|
|
{ |
252 |
|
|
debug2("channel %d: rcvd eof", c->self); |
253 |
|
|
c->flags |= CHAN_EOF_RCVD; |
254 |
|
|
if (c->ostate == CHAN_OUTPUT_OPEN) |
255 |
|
|
chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN); |
256 |
|
|
if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN && |
257 |
|
|
sshbuf_len(c->output) == 0 && |
258 |
|
|
!CHANNEL_EFD_OUTPUT_ACTIVE(c)) |
259 |
|
|
chan_obuf_empty(ssh, c); |
260 |
|
|
} |
261 |
|
|
|
262 |
|
|
void |
263 |
|
|
chan_rcvd_oclose(struct ssh *ssh, Channel *c) |
264 |
|
|
{ |
265 |
|
|
debug2("channel %d: rcvd close", c->self); |
266 |
|
|
if (!(c->flags & CHAN_LOCAL)) { |
267 |
|
|
if (c->flags & CHAN_CLOSE_RCVD) |
268 |
|
|
error("channel %d: protocol error: close rcvd twice", |
269 |
|
|
c->self); |
270 |
|
|
c->flags |= CHAN_CLOSE_RCVD; |
271 |
|
|
} |
272 |
|
|
if (c->type == SSH_CHANNEL_LARVAL) { |
273 |
|
|
/* tear down larval channels immediately */ |
274 |
|
|
chan_set_ostate(c, CHAN_OUTPUT_CLOSED); |
275 |
|
|
chan_set_istate(c, CHAN_INPUT_CLOSED); |
276 |
|
|
return; |
277 |
|
|
} |
278 |
|
|
switch (c->ostate) { |
279 |
|
|
case CHAN_OUTPUT_OPEN: |
280 |
|
|
/* |
281 |
|
|
* wait until a data from the channel is consumed if a CLOSE |
282 |
|
|
* is received |
283 |
|
|
*/ |
284 |
|
|
chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN); |
285 |
|
|
break; |
286 |
|
|
} |
287 |
|
|
switch (c->istate) { |
288 |
|
|
case CHAN_INPUT_OPEN: |
289 |
|
|
chan_shutdown_read(ssh, c); |
290 |
|
|
chan_set_istate(c, CHAN_INPUT_CLOSED); |
291 |
|
|
break; |
292 |
|
|
case CHAN_INPUT_WAIT_DRAIN: |
293 |
|
|
if (!(c->flags & CHAN_LOCAL)) |
294 |
|
|
chan_send_eof2(ssh, c); |
295 |
|
|
chan_set_istate(c, CHAN_INPUT_CLOSED); |
296 |
|
|
break; |
297 |
|
|
} |
298 |
|
|
} |
299 |
|
|
|
300 |
|
|
void |
301 |
|
|
chan_write_failed(struct ssh *ssh, Channel *c) |
302 |
|
|
{ |
303 |
|
|
debug2("channel %d: write failed", c->self); |
304 |
|
|
switch (c->ostate) { |
305 |
|
|
case CHAN_OUTPUT_OPEN: |
306 |
|
|
case CHAN_OUTPUT_WAIT_DRAIN: |
307 |
|
|
chan_shutdown_write(ssh, c); |
308 |
|
|
if (strcmp(c->ctype, "session") == 0) |
309 |
|
|
chan_send_eow2(ssh, c); |
310 |
|
|
chan_set_ostate(c, CHAN_OUTPUT_CLOSED); |
311 |
|
|
break; |
312 |
|
|
default: |
313 |
|
|
error("channel %d: chan_write_failed for ostate %d", |
314 |
|
|
c->self, c->ostate); |
315 |
|
|
break; |
316 |
|
|
} |
317 |
|
|
} |
318 |
|
|
|
319 |
|
|
void |
320 |
|
|
chan_mark_dead(struct ssh *ssh, Channel *c) |
321 |
|
|
{ |
322 |
|
|
c->type = SSH_CHANNEL_ZOMBIE; |
323 |
|
|
} |
324 |
|
|
|
325 |
|
|
int |
326 |
|
|
chan_is_dead(struct ssh *ssh, Channel *c, int do_send) |
327 |
|
|
{ |
328 |
|
|
if (c->type == SSH_CHANNEL_ZOMBIE) { |
329 |
|
|
debug2("channel %d: zombie", c->self); |
330 |
|
|
return 1; |
331 |
|
|
} |
332 |
|
|
if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED) |
333 |
|
|
return 0; |
334 |
|
|
if ((datafellows & SSH_BUG_EXTEOF) && |
335 |
|
|
c->extended_usage == CHAN_EXTENDED_WRITE && |
336 |
|
|
c->efd != -1 && |
337 |
|
|
sshbuf_len(c->extended) > 0) { |
338 |
|
|
debug2("channel %d: active efd: %d len %zu", |
339 |
|
|
c->self, c->efd, sshbuf_len(c->extended)); |
340 |
|
|
return 0; |
341 |
|
|
} |
342 |
|
|
if (c->flags & CHAN_LOCAL) { |
343 |
|
|
debug2("channel %d: is dead (local)", c->self); |
344 |
|
|
return 1; |
345 |
|
|
} |
346 |
|
|
if (!(c->flags & CHAN_CLOSE_SENT)) { |
347 |
|
|
if (do_send) { |
348 |
|
|
chan_send_close2(ssh, c); |
349 |
|
|
} else { |
350 |
|
|
/* channel would be dead if we sent a close */ |
351 |
|
|
if (c->flags & CHAN_CLOSE_RCVD) { |
352 |
|
|
debug2("channel %d: almost dead", |
353 |
|
|
c->self); |
354 |
|
|
return 1; |
355 |
|
|
} |
356 |
|
|
} |
357 |
|
|
} |
358 |
|
|
if ((c->flags & CHAN_CLOSE_SENT) && |
359 |
|
|
(c->flags & CHAN_CLOSE_RCVD)) { |
360 |
|
|
debug2("channel %d: is dead", c->self); |
361 |
|
|
return 1; |
362 |
|
|
} |
363 |
|
|
return 0; |
364 |
|
|
} |
365 |
|
|
|
366 |
|
|
/* helper */ |
367 |
|
|
static void |
368 |
|
|
chan_shutdown_write(struct ssh *ssh, Channel *c) |
369 |
|
|
{ |
370 |
|
|
sshbuf_reset(c->output); |
371 |
|
|
if (c->type == SSH_CHANNEL_LARVAL) |
372 |
|
|
return; |
373 |
|
|
/* shutdown failure is allowed if write failed already */ |
374 |
|
|
debug2("channel %d: close_write", c->self); |
375 |
|
|
if (c->sock != -1) { |
376 |
|
|
if (shutdown(c->sock, SHUT_WR) < 0) |
377 |
|
|
debug2("channel %d: chan_shutdown_write: " |
378 |
|
|
"shutdown() failed for fd %d: %.100s", |
379 |
|
|
c->self, c->sock, strerror(errno)); |
380 |
|
|
} else { |
381 |
|
|
if (channel_close_fd(ssh, &c->wfd) < 0) |
382 |
|
|
logit("channel %d: chan_shutdown_write: " |
383 |
|
|
"close() failed for fd %d: %.100s", |
384 |
|
|
c->self, c->wfd, strerror(errno)); |
385 |
|
|
} |
386 |
|
|
} |
387 |
|
|
|
388 |
|
|
static void |
389 |
|
|
chan_shutdown_read(struct ssh *ssh, Channel *c) |
390 |
|
|
{ |
391 |
|
|
if (c->type == SSH_CHANNEL_LARVAL) |
392 |
|
|
return; |
393 |
|
|
debug2("channel %d: close_read", c->self); |
394 |
|
|
if (c->sock != -1) { |
395 |
|
|
if (shutdown(c->sock, SHUT_RD) < 0) |
396 |
|
|
error("channel %d: chan_shutdown_read: " |
397 |
|
|
"shutdown() failed for fd %d [i%d o%d]: %.100s", |
398 |
|
|
c->self, c->sock, c->istate, c->ostate, |
399 |
|
|
strerror(errno)); |
400 |
|
|
} else { |
401 |
|
|
if (channel_close_fd(ssh, &c->rfd) < 0) |
402 |
|
|
logit("channel %d: chan_shutdown_read: " |
403 |
|
|
"close() failed for fd %d: %.100s", |
404 |
|
|
c->self, c->rfd, strerror(errno)); |
405 |
|
|
} |
406 |
|
|
} |