Annotation of src/usr.bin/ssh/nchan.c, Revision 1.56
1.56 ! stevesk 1: /* $OpenBSD: nchan.c,v 1.55 2006/07/11 20:07:25 stevesk Exp $ */
1.7 markus 2: /*
1.43 markus 3: * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
1.7 markus 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:
1.1 markus 26: #include "includes.h"
1.54 stevesk 27:
28: #include <sys/types.h>
29: #include <sys/socket.h>
1.55 stevesk 30:
31: #include <errno.h>
1.56 ! stevesk 32: #include <string.h>
1.1 markus 33:
1.22 markus 34: #include "ssh1.h"
35: #include "ssh2.h"
1.1 markus 36: #include "buffer.h"
1.3 markus 37: #include "packet.h"
1.1 markus 38: #include "channels.h"
1.13 markus 39: #include "compat.h"
1.22 markus 40: #include "log.h"
1.3 markus 41:
1.28 markus 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:
1.51 deraadt 51: * CLOSE ->
52: * <- CLOSE_CONFIRM
1.28 markus 53: *
54: * 1.5: uses variations of:
1.51 deraadt 55: * IEOF ->
56: * <- OCLOSE
57: * <- IEOF
58: * OCLOSE ->
59: * i.e. both sides have to close the channel
1.28 markus 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:
1.13 markus 68: /* functions manipulating channel states */
1.3 markus 69: /*
1.6 markus 70: * EVENTS update channel input/output states execute ACTIONS
1.3 markus 71: */
1.13 markus 72: /*
73: * ACTIONS: should never update the channel states
74: */
1.29 itojun 75: static void chan_send_ieof1(Channel *);
76: static void chan_send_oclose1(Channel *);
77: static void chan_send_close2(Channel *);
78: static void chan_send_eof2(Channel *);
1.13 markus 79:
80: /* helper */
1.29 itojun 81: static void chan_shutdown_write(Channel *);
82: static void chan_shutdown_read(Channel *);
1.13 markus 83:
1.37 markus 84: static char *ostates[] = { "open", "drain", "wait_ieof", "closed" };
85: static char *istates[] = { "open", "drain", "wait_oclose", "closed" };
86:
87: static void
88: chan_set_istate(Channel *c, u_int next)
89: {
90: if (c->istate > CHAN_INPUT_CLOSED || next > CHAN_INPUT_CLOSED)
91: fatal("chan_set_istate: bad state %d -> %d", c->istate, next);
1.49 markus 92: debug2("channel %d: input %s -> %s", c->self, istates[c->istate],
1.37 markus 93: istates[next]);
94: c->istate = next;
95: }
96: static void
97: chan_set_ostate(Channel *c, u_int next)
98: {
99: if (c->ostate > CHAN_OUTPUT_CLOSED || next > CHAN_OUTPUT_CLOSED)
100: fatal("chan_set_ostate: bad state %d -> %d", c->ostate, next);
1.49 markus 101: debug2("channel %d: output %s -> %s", c->self, ostates[c->ostate],
1.37 markus 102: ostates[next]);
103: c->ostate = next;
104: }
105:
1.13 markus 106: /*
107: * SSH1 specific implementation of event functions
108: */
1.6 markus 109:
1.13 markus 110: static void
111: chan_rcvd_oclose1(Channel *c)
1.6 markus 112: {
1.49 markus 113: debug2("channel %d: rcvd oclose", c->self);
1.6 markus 114: switch (c->istate) {
1.3 markus 115: case CHAN_INPUT_WAIT_OCLOSE:
1.37 markus 116: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.3 markus 117: break;
118: case CHAN_INPUT_OPEN:
119: chan_shutdown_read(c);
1.13 markus 120: chan_send_ieof1(c);
1.37 markus 121: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.10 markus 122: break;
123: case CHAN_INPUT_WAIT_DRAIN:
124: /* both local read_failed and remote write_failed */
1.13 markus 125: chan_send_ieof1(c);
1.37 markus 126: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.3 markus 127: break;
128: default:
1.28 markus 129: error("channel %d: protocol error: rcvd_oclose for istate %d",
1.13 markus 130: c->self, c->istate);
1.10 markus 131: return;
1.3 markus 132: }
1.1 markus 133: }
1.42 markus 134: void
135: chan_read_failed(Channel *c)
1.6 markus 136: {
1.49 markus 137: debug2("channel %d: read failed", c->self);
1.6 markus 138: switch (c->istate) {
1.3 markus 139: case CHAN_INPUT_OPEN:
140: chan_shutdown_read(c);
1.37 markus 141: chan_set_istate(c, CHAN_INPUT_WAIT_DRAIN);
1.3 markus 142: break;
143: default:
1.28 markus 144: error("channel %d: chan_read_failed for istate %d",
1.13 markus 145: c->self, c->istate);
1.3 markus 146: break;
1.1 markus 147: }
148: }
1.42 markus 149: void
150: chan_ibuf_empty(Channel *c)
1.6 markus 151: {
1.49 markus 152: debug2("channel %d: ibuf empty", c->self);
1.6 markus 153: if (buffer_len(&c->input)) {
1.28 markus 154: error("channel %d: chan_ibuf_empty for non empty buffer",
1.13 markus 155: c->self);
1.3 markus 156: return;
157: }
1.6 markus 158: switch (c->istate) {
1.3 markus 159: case CHAN_INPUT_WAIT_DRAIN:
1.39 markus 160: if (compat20) {
161: if (!(c->flags & CHAN_CLOSE_SENT))
162: chan_send_eof2(c);
163: chan_set_istate(c, CHAN_INPUT_CLOSED);
164: } else {
165: chan_send_ieof1(c);
166: chan_set_istate(c, CHAN_INPUT_WAIT_OCLOSE);
167: }
1.3 markus 168: break;
169: default:
1.28 markus 170: error("channel %d: chan_ibuf_empty for istate %d",
1.13 markus 171: c->self, c->istate);
1.3 markus 172: break;
1.1 markus 173: }
174: }
1.13 markus 175: static void
176: chan_rcvd_ieof1(Channel *c)
1.6 markus 177: {
1.49 markus 178: debug2("channel %d: rcvd ieof", c->self);
1.6 markus 179: switch (c->ostate) {
1.3 markus 180: case CHAN_OUTPUT_OPEN:
1.37 markus 181: chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
1.3 markus 182: break;
183: case CHAN_OUTPUT_WAIT_IEOF:
1.37 markus 184: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
1.3 markus 185: break;
186: default:
1.28 markus 187: error("channel %d: protocol error: rcvd_ieof for ostate %d",
1.13 markus 188: c->self, c->ostate);
1.3 markus 189: break;
190: }
191: }
1.13 markus 192: static void
193: chan_write_failed1(Channel *c)
1.6 markus 194: {
1.49 markus 195: debug2("channel %d: write failed", c->self);
1.6 markus 196: switch (c->ostate) {
1.3 markus 197: case CHAN_OUTPUT_OPEN:
1.38 markus 198: chan_shutdown_write(c);
1.13 markus 199: chan_send_oclose1(c);
1.37 markus 200: chan_set_ostate(c, CHAN_OUTPUT_WAIT_IEOF);
1.3 markus 201: break;
202: case CHAN_OUTPUT_WAIT_DRAIN:
1.38 markus 203: chan_shutdown_write(c);
1.13 markus 204: chan_send_oclose1(c);
1.37 markus 205: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
1.3 markus 206: break;
207: default:
1.28 markus 208: error("channel %d: chan_write_failed for ostate %d",
1.13 markus 209: c->self, c->ostate);
1.3 markus 210: break;
211: }
212: }
1.42 markus 213: void
214: chan_obuf_empty(Channel *c)
1.6 markus 215: {
1.49 markus 216: debug2("channel %d: obuf empty", c->self);
1.6 markus 217: if (buffer_len(&c->output)) {
1.28 markus 218: error("channel %d: chan_obuf_empty for non empty buffer",
1.13 markus 219: c->self);
1.3 markus 220: return;
221: }
1.6 markus 222: switch (c->ostate) {
1.3 markus 223: case CHAN_OUTPUT_WAIT_DRAIN:
1.38 markus 224: chan_shutdown_write(c);
1.39 markus 225: if (!compat20)
226: chan_send_oclose1(c);
1.37 markus 227: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
1.3 markus 228: break;
229: default:
1.28 markus 230: error("channel %d: internal error: obuf_empty for ostate %d",
1.13 markus 231: c->self, c->ostate);
1.3 markus 232: break;
233: }
234: }
235: static void
1.13 markus 236: chan_send_ieof1(Channel *c)
1.6 markus 237: {
1.49 markus 238: debug2("channel %d: send ieof", c->self);
1.6 markus 239: switch (c->istate) {
1.3 markus 240: case CHAN_INPUT_OPEN:
241: case CHAN_INPUT_WAIT_DRAIN:
242: packet_start(SSH_MSG_CHANNEL_INPUT_EOF);
243: packet_put_int(c->remote_id);
244: packet_send();
245: break;
246: default:
1.28 markus 247: error("channel %d: cannot send ieof for istate %d",
1.13 markus 248: c->self, c->istate);
1.3 markus 249: break;
1.1 markus 250: }
251: }
1.3 markus 252: static void
1.13 markus 253: chan_send_oclose1(Channel *c)
1.6 markus 254: {
1.49 markus 255: debug2("channel %d: send oclose", c->self);
1.6 markus 256: switch (c->ostate) {
1.3 markus 257: case CHAN_OUTPUT_OPEN:
258: case CHAN_OUTPUT_WAIT_DRAIN:
1.34 markus 259: buffer_clear(&c->output);
1.3 markus 260: packet_start(SSH_MSG_CHANNEL_OUTPUT_CLOSE);
261: packet_put_int(c->remote_id);
262: packet_send();
263: break;
264: default:
1.28 markus 265: error("channel %d: cannot send oclose for ostate %d",
1.33 deraadt 266: c->self, c->ostate);
1.3 markus 267: break;
1.1 markus 268: }
269: }
1.6 markus 270:
1.13 markus 271: /*
272: * the same for SSH2
273: */
274: static void
1.40 markus 275: chan_rcvd_close2(Channel *c)
1.13 markus 276: {
1.49 markus 277: debug2("channel %d: rcvd close", c->self);
1.13 markus 278: if (c->flags & CHAN_CLOSE_RCVD)
279: error("channel %d: protocol error: close rcvd twice", c->self);
280: c->flags |= CHAN_CLOSE_RCVD;
281: if (c->type == SSH_CHANNEL_LARVAL) {
282: /* tear down larval channels immediately */
1.37 markus 283: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
284: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.13 markus 285: return;
286: }
287: switch (c->ostate) {
288: case CHAN_OUTPUT_OPEN:
1.28 markus 289: /*
290: * wait until a data from the channel is consumed if a CLOSE
291: * is received
292: */
1.37 markus 293: chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
1.13 markus 294: break;
295: }
296: switch (c->istate) {
297: case CHAN_INPUT_OPEN:
298: chan_shutdown_read(c);
1.40 markus 299: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.13 markus 300: break;
301: case CHAN_INPUT_WAIT_DRAIN:
302: chan_send_eof2(c);
1.40 markus 303: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.13 markus 304: break;
305: }
306: }
307: static void
1.40 markus 308: chan_rcvd_eof2(Channel *c)
1.13 markus 309: {
1.49 markus 310: debug2("channel %d: rcvd eof", c->self);
1.45 markus 311: c->flags |= CHAN_EOF_RCVD;
1.37 markus 312: if (c->ostate == CHAN_OUTPUT_OPEN)
313: chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
1.13 markus 314: }
315: static void
316: chan_write_failed2(Channel *c)
317: {
1.49 markus 318: debug2("channel %d: write failed", c->self);
1.13 markus 319: switch (c->ostate) {
320: case CHAN_OUTPUT_OPEN:
321: case CHAN_OUTPUT_WAIT_DRAIN:
322: chan_shutdown_write(c);
1.37 markus 323: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
1.13 markus 324: break;
325: default:
1.28 markus 326: error("channel %d: chan_write_failed for ostate %d",
1.13 markus 327: c->self, c->ostate);
328: break;
329: }
330: }
331: static void
332: chan_send_eof2(Channel *c)
1.6 markus 333: {
1.49 markus 334: debug2("channel %d: send eof", c->self);
1.13 markus 335: switch (c->istate) {
336: case CHAN_INPUT_WAIT_DRAIN:
337: packet_start(SSH2_MSG_CHANNEL_EOF);
338: packet_put_int(c->remote_id);
339: packet_send();
1.45 markus 340: c->flags |= CHAN_EOF_SENT;
1.13 markus 341: break;
342: default:
1.28 markus 343: error("channel %d: cannot send eof for istate %d",
1.13 markus 344: c->self, c->istate);
345: break;
346: }
1.1 markus 347: }
1.3 markus 348: static void
1.13 markus 349: chan_send_close2(Channel *c)
1.6 markus 350: {
1.49 markus 351: debug2("channel %d: send close", c->self);
1.13 markus 352: if (c->ostate != CHAN_OUTPUT_CLOSED ||
353: c->istate != CHAN_INPUT_CLOSED) {
1.28 markus 354: error("channel %d: cannot send close for istate/ostate %d/%d",
1.13 markus 355: c->self, c->istate, c->ostate);
356: } else if (c->flags & CHAN_CLOSE_SENT) {
1.28 markus 357: error("channel %d: already sent close", c->self);
1.13 markus 358: } else {
359: packet_start(SSH2_MSG_CHANNEL_CLOSE);
360: packet_put_int(c->remote_id);
361: packet_send();
362: c->flags |= CHAN_CLOSE_SENT;
363: }
1.1 markus 364: }
1.23 markus 365:
366: /* shared */
367:
1.24 markus 368: void
1.42 markus 369: chan_rcvd_ieof(Channel *c)
370: {
371: if (compat20)
372: chan_rcvd_eof2(c);
373: else
374: chan_rcvd_ieof1(c);
1.44 markus 375: if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN &&
1.47 deraadt 376: buffer_len(&c->output) == 0 &&
1.45 markus 377: !CHANNEL_EFD_OUTPUT_ACTIVE(c))
1.44 markus 378: chan_obuf_empty(c);
1.42 markus 379: }
380: void
381: chan_rcvd_oclose(Channel *c)
382: {
383: if (compat20)
384: chan_rcvd_close2(c);
385: else
386: chan_rcvd_oclose1(c);
387: }
388: void
389: chan_write_failed(Channel *c)
390: {
391: if (compat20)
392: chan_write_failed2(c);
393: else
394: chan_write_failed1(c);
395: }
396:
397: void
1.24 markus 398: chan_mark_dead(Channel *c)
399: {
1.26 markus 400: c->type = SSH_CHANNEL_ZOMBIE;
1.24 markus 401: }
402:
1.23 markus 403: int
1.50 avsm 404: chan_is_dead(Channel *c, int do_send)
1.6 markus 405: {
1.26 markus 406: if (c->type == SSH_CHANNEL_ZOMBIE) {
1.49 markus 407: debug2("channel %d: zombie", c->self);
1.24 markus 408: return 1;
1.26 markus 409: }
1.23 markus 410: if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
411: return 0;
412: if (!compat20) {
1.49 markus 413: debug2("channel %d: is dead", c->self);
1.23 markus 414: return 1;
415: }
1.45 markus 416: if ((datafellows & SSH_BUG_EXTEOF) &&
417: c->extended_usage == CHAN_EXTENDED_WRITE &&
418: c->efd != -1 &&
419: buffer_len(&c->extended) > 0) {
1.46 markus 420: debug2("channel %d: active efd: %d len %d",
421: c->self, c->efd, buffer_len(&c->extended));
1.45 markus 422: return 0;
423: }
424: if (!(c->flags & CHAN_CLOSE_SENT)) {
1.50 avsm 425: if (do_send) {
1.45 markus 426: chan_send_close2(c);
427: } else {
428: /* channel would be dead if we sent a close */
429: if (c->flags & CHAN_CLOSE_RCVD) {
1.49 markus 430: debug2("channel %d: almost dead",
1.45 markus 431: c->self);
432: return 1;
1.32 markus 433: }
1.13 markus 434: }
1.45 markus 435: }
436: if ((c->flags & CHAN_CLOSE_SENT) &&
437: (c->flags & CHAN_CLOSE_RCVD)) {
1.49 markus 438: debug2("channel %d: is dead", c->self);
1.45 markus 439: return 1;
1.1 markus 440: }
1.23 markus 441: return 0;
1.13 markus 442: }
443:
444: /* helper */
445: static void
446: chan_shutdown_write(Channel *c)
447: {
1.34 markus 448: buffer_clear(&c->output);
1.13 markus 449: if (compat20 && c->type == SSH_CHANNEL_LARVAL)
450: return;
451: /* shutdown failure is allowed if write failed already */
1.49 markus 452: debug2("channel %d: close_write", c->self);
1.13 markus 453: if (c->sock != -1) {
454: if (shutdown(c->sock, SHUT_WR) < 0)
1.49 markus 455: debug2("channel %d: chan_shutdown_write: "
1.28 markus 456: "shutdown() failed for fd%d: %.100s",
1.13 markus 457: c->self, c->sock, strerror(errno));
458: } else {
1.31 markus 459: if (channel_close_fd(&c->wfd) < 0)
1.48 itojun 460: logit("channel %d: chan_shutdown_write: "
1.28 markus 461: "close() failed for fd%d: %.100s",
1.13 markus 462: c->self, c->wfd, strerror(errno));
463: }
464: }
465: static void
466: chan_shutdown_read(Channel *c)
467: {
468: if (compat20 && c->type == SSH_CHANNEL_LARVAL)
469: return;
1.49 markus 470: debug2("channel %d: close_read", c->self);
1.13 markus 471: if (c->sock != -1) {
472: if (shutdown(c->sock, SHUT_RD) < 0)
1.28 markus 473: error("channel %d: chan_shutdown_read: "
474: "shutdown() failed for fd%d [i%d o%d]: %.100s",
475: c->self, c->sock, c->istate, c->ostate,
476: strerror(errno));
1.13 markus 477: } else {
1.31 markus 478: if (channel_close_fd(&c->rfd) < 0)
1.48 itojun 479: logit("channel %d: chan_shutdown_read: "
1.28 markus 480: "close() failed for fd%d: %.100s",
1.13 markus 481: c->self, c->rfd, strerror(errno));
482: }
1.1 markus 483: }
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