Annotation of src/usr.bin/ssh/nchan.c, Revision 1.61
1.61 ! markus 1: /* $OpenBSD: nchan.c,v 1.60 2008/06/30 12:16:02 djm 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:
1.54 stevesk 26: #include <sys/types.h>
27: #include <sys/socket.h>
1.58 djm 28: #include <sys/queue.h>
1.55 stevesk 29:
30: #include <errno.h>
1.56 stevesk 31: #include <string.h>
1.57 deraadt 32: #include <stdarg.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 *);
1.59 markus 79: static void chan_send_eow2(Channel *);
1.13 markus 80:
81: /* helper */
1.29 itojun 82: static void chan_shutdown_write(Channel *);
83: static void chan_shutdown_read(Channel *);
1.13 markus 84:
1.37 markus 85: static char *ostates[] = { "open", "drain", "wait_ieof", "closed" };
86: static char *istates[] = { "open", "drain", "wait_oclose", "closed" };
87:
88: static void
89: chan_set_istate(Channel *c, u_int next)
90: {
91: if (c->istate > CHAN_INPUT_CLOSED || next > CHAN_INPUT_CLOSED)
92: fatal("chan_set_istate: bad state %d -> %d", c->istate, next);
1.49 markus 93: debug2("channel %d: input %s -> %s", c->self, istates[c->istate],
1.37 markus 94: istates[next]);
95: c->istate = next;
96: }
97: static void
98: chan_set_ostate(Channel *c, u_int next)
99: {
100: if (c->ostate > CHAN_OUTPUT_CLOSED || next > CHAN_OUTPUT_CLOSED)
101: fatal("chan_set_ostate: bad state %d -> %d", c->ostate, next);
1.49 markus 102: debug2("channel %d: output %s -> %s", c->self, ostates[c->ostate],
1.37 markus 103: ostates[next]);
104: c->ostate = next;
105: }
106:
1.13 markus 107: /*
108: * SSH1 specific implementation of event functions
109: */
1.6 markus 110:
1.13 markus 111: static void
112: chan_rcvd_oclose1(Channel *c)
1.6 markus 113: {
1.49 markus 114: debug2("channel %d: rcvd oclose", c->self);
1.6 markus 115: switch (c->istate) {
1.3 markus 116: case CHAN_INPUT_WAIT_OCLOSE:
1.37 markus 117: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.3 markus 118: break;
119: case CHAN_INPUT_OPEN:
120: chan_shutdown_read(c);
1.13 markus 121: chan_send_ieof1(c);
1.37 markus 122: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.10 markus 123: break;
124: case CHAN_INPUT_WAIT_DRAIN:
125: /* both local read_failed and remote write_failed */
1.13 markus 126: chan_send_ieof1(c);
1.37 markus 127: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.3 markus 128: break;
129: default:
1.28 markus 130: error("channel %d: protocol error: rcvd_oclose for istate %d",
1.13 markus 131: c->self, c->istate);
1.10 markus 132: return;
1.3 markus 133: }
1.1 markus 134: }
1.42 markus 135: void
136: chan_read_failed(Channel *c)
1.6 markus 137: {
1.49 markus 138: debug2("channel %d: read failed", c->self);
1.6 markus 139: switch (c->istate) {
1.3 markus 140: case CHAN_INPUT_OPEN:
141: chan_shutdown_read(c);
1.37 markus 142: chan_set_istate(c, CHAN_INPUT_WAIT_DRAIN);
1.3 markus 143: break;
144: default:
1.28 markus 145: error("channel %d: chan_read_failed for istate %d",
1.13 markus 146: c->self, c->istate);
1.3 markus 147: break;
1.1 markus 148: }
149: }
1.42 markus 150: void
151: chan_ibuf_empty(Channel *c)
1.6 markus 152: {
1.49 markus 153: debug2("channel %d: ibuf empty", c->self);
1.6 markus 154: if (buffer_len(&c->input)) {
1.28 markus 155: error("channel %d: chan_ibuf_empty for non empty buffer",
1.13 markus 156: c->self);
1.3 markus 157: return;
158: }
1.6 markus 159: switch (c->istate) {
1.3 markus 160: case CHAN_INPUT_WAIT_DRAIN:
1.39 markus 161: if (compat20) {
162: if (!(c->flags & CHAN_CLOSE_SENT))
163: chan_send_eof2(c);
164: chan_set_istate(c, CHAN_INPUT_CLOSED);
165: } else {
166: chan_send_ieof1(c);
167: chan_set_istate(c, CHAN_INPUT_WAIT_OCLOSE);
168: }
1.3 markus 169: break;
170: default:
1.28 markus 171: error("channel %d: chan_ibuf_empty for istate %d",
1.13 markus 172: c->self, c->istate);
1.3 markus 173: break;
1.1 markus 174: }
175: }
1.13 markus 176: static void
177: chan_rcvd_ieof1(Channel *c)
1.6 markus 178: {
1.49 markus 179: debug2("channel %d: rcvd ieof", c->self);
1.6 markus 180: switch (c->ostate) {
1.3 markus 181: case CHAN_OUTPUT_OPEN:
1.37 markus 182: chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
1.3 markus 183: break;
184: case CHAN_OUTPUT_WAIT_IEOF:
1.37 markus 185: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
1.3 markus 186: break;
187: default:
1.28 markus 188: error("channel %d: protocol error: rcvd_ieof for ostate %d",
1.13 markus 189: c->self, c->ostate);
1.3 markus 190: break;
191: }
192: }
1.13 markus 193: static void
194: chan_write_failed1(Channel *c)
1.6 markus 195: {
1.49 markus 196: debug2("channel %d: write failed", c->self);
1.6 markus 197: switch (c->ostate) {
1.3 markus 198: case CHAN_OUTPUT_OPEN:
1.38 markus 199: chan_shutdown_write(c);
1.13 markus 200: chan_send_oclose1(c);
1.37 markus 201: chan_set_ostate(c, CHAN_OUTPUT_WAIT_IEOF);
1.3 markus 202: break;
203: case CHAN_OUTPUT_WAIT_DRAIN:
1.38 markus 204: chan_shutdown_write(c);
1.13 markus 205: chan_send_oclose1(c);
1.37 markus 206: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
1.3 markus 207: break;
208: default:
1.28 markus 209: error("channel %d: chan_write_failed for ostate %d",
1.13 markus 210: c->self, c->ostate);
1.3 markus 211: break;
212: }
213: }
1.42 markus 214: void
215: chan_obuf_empty(Channel *c)
1.6 markus 216: {
1.49 markus 217: debug2("channel %d: obuf empty", c->self);
1.6 markus 218: if (buffer_len(&c->output)) {
1.28 markus 219: error("channel %d: chan_obuf_empty for non empty buffer",
1.13 markus 220: c->self);
1.3 markus 221: return;
222: }
1.6 markus 223: switch (c->ostate) {
1.3 markus 224: case CHAN_OUTPUT_WAIT_DRAIN:
1.38 markus 225: chan_shutdown_write(c);
1.39 markus 226: if (!compat20)
227: chan_send_oclose1(c);
1.37 markus 228: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
1.3 markus 229: break;
230: default:
1.28 markus 231: error("channel %d: internal error: obuf_empty for ostate %d",
1.13 markus 232: c->self, c->ostate);
1.3 markus 233: break;
234: }
235: }
236: static void
1.13 markus 237: chan_send_ieof1(Channel *c)
1.6 markus 238: {
1.49 markus 239: debug2("channel %d: send ieof", c->self);
1.6 markus 240: switch (c->istate) {
1.3 markus 241: case CHAN_INPUT_OPEN:
242: case CHAN_INPUT_WAIT_DRAIN:
243: packet_start(SSH_MSG_CHANNEL_INPUT_EOF);
244: packet_put_int(c->remote_id);
245: packet_send();
246: break;
247: default:
1.28 markus 248: error("channel %d: cannot send ieof for istate %d",
1.13 markus 249: c->self, c->istate);
1.3 markus 250: break;
1.1 markus 251: }
252: }
1.3 markus 253: static void
1.13 markus 254: chan_send_oclose1(Channel *c)
1.6 markus 255: {
1.49 markus 256: debug2("channel %d: send oclose", c->self);
1.6 markus 257: switch (c->ostate) {
1.3 markus 258: case CHAN_OUTPUT_OPEN:
259: case CHAN_OUTPUT_WAIT_DRAIN:
1.34 markus 260: buffer_clear(&c->output);
1.3 markus 261: packet_start(SSH_MSG_CHANNEL_OUTPUT_CLOSE);
262: packet_put_int(c->remote_id);
263: packet_send();
264: break;
265: default:
1.28 markus 266: error("channel %d: cannot send oclose for ostate %d",
1.33 deraadt 267: c->self, c->ostate);
1.3 markus 268: break;
1.1 markus 269: }
270: }
1.6 markus 271:
1.13 markus 272: /*
273: * the same for SSH2
274: */
275: static void
1.40 markus 276: chan_rcvd_close2(Channel *c)
1.13 markus 277: {
1.49 markus 278: debug2("channel %d: rcvd close", c->self);
1.13 markus 279: if (c->flags & CHAN_CLOSE_RCVD)
280: error("channel %d: protocol error: close rcvd twice", c->self);
281: c->flags |= CHAN_CLOSE_RCVD;
282: if (c->type == SSH_CHANNEL_LARVAL) {
283: /* tear down larval channels immediately */
1.37 markus 284: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
285: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.13 markus 286: return;
287: }
288: switch (c->ostate) {
289: case CHAN_OUTPUT_OPEN:
1.28 markus 290: /*
291: * wait until a data from the channel is consumed if a CLOSE
292: * is received
293: */
1.37 markus 294: chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
1.13 markus 295: break;
296: }
297: switch (c->istate) {
298: case CHAN_INPUT_OPEN:
299: chan_shutdown_read(c);
1.40 markus 300: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.13 markus 301: break;
302: case CHAN_INPUT_WAIT_DRAIN:
303: chan_send_eof2(c);
1.40 markus 304: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.13 markus 305: break;
306: }
307: }
1.59 markus 308: void
309: chan_rcvd_eow(Channel *c)
310: {
311: debug2("channel %d: rcvd eow", c->self);
312: switch (c->istate) {
313: case CHAN_INPUT_OPEN:
314: chan_shutdown_read(c);
315: chan_set_istate(c, CHAN_INPUT_CLOSED);
316: break;
317: }
318: }
1.13 markus 319: static void
1.40 markus 320: chan_rcvd_eof2(Channel *c)
1.13 markus 321: {
1.49 markus 322: debug2("channel %d: rcvd eof", c->self);
1.45 markus 323: c->flags |= CHAN_EOF_RCVD;
1.37 markus 324: if (c->ostate == CHAN_OUTPUT_OPEN)
325: chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
1.13 markus 326: }
327: static void
328: chan_write_failed2(Channel *c)
329: {
1.49 markus 330: debug2("channel %d: write failed", c->self);
1.13 markus 331: switch (c->ostate) {
332: case CHAN_OUTPUT_OPEN:
333: case CHAN_OUTPUT_WAIT_DRAIN:
334: chan_shutdown_write(c);
1.60 djm 335: if (strcmp(c->ctype, "session") == 0)
336: chan_send_eow2(c);
1.37 markus 337: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
1.13 markus 338: break;
339: default:
1.28 markus 340: error("channel %d: chan_write_failed for ostate %d",
1.13 markus 341: c->self, c->ostate);
342: break;
343: }
344: }
345: static void
346: chan_send_eof2(Channel *c)
1.6 markus 347: {
1.49 markus 348: debug2("channel %d: send eof", c->self);
1.13 markus 349: switch (c->istate) {
350: case CHAN_INPUT_WAIT_DRAIN:
351: packet_start(SSH2_MSG_CHANNEL_EOF);
352: packet_put_int(c->remote_id);
353: packet_send();
1.45 markus 354: c->flags |= CHAN_EOF_SENT;
1.13 markus 355: break;
356: default:
1.28 markus 357: error("channel %d: cannot send eof for istate %d",
1.13 markus 358: c->self, c->istate);
359: break;
360: }
1.1 markus 361: }
1.3 markus 362: static void
1.13 markus 363: chan_send_close2(Channel *c)
1.6 markus 364: {
1.49 markus 365: debug2("channel %d: send close", c->self);
1.13 markus 366: if (c->ostate != CHAN_OUTPUT_CLOSED ||
367: c->istate != CHAN_INPUT_CLOSED) {
1.28 markus 368: error("channel %d: cannot send close for istate/ostate %d/%d",
1.13 markus 369: c->self, c->istate, c->ostate);
370: } else if (c->flags & CHAN_CLOSE_SENT) {
1.28 markus 371: error("channel %d: already sent close", c->self);
1.13 markus 372: } else {
373: packet_start(SSH2_MSG_CHANNEL_CLOSE);
374: packet_put_int(c->remote_id);
375: packet_send();
376: c->flags |= CHAN_CLOSE_SENT;
377: }
1.59 markus 378: }
379: static void
380: chan_send_eow2(Channel *c)
381: {
382: debug2("channel %d: send eow", c->self);
383: if (c->ostate == CHAN_OUTPUT_CLOSED) {
384: error("channel %d: must not sent eow on closed output",
385: c->self);
386: return;
387: }
1.61 ! markus 388: if (!(datafellows & SSH_NEW_OPENSSH))
! 389: return;
1.59 markus 390: packet_start(SSH2_MSG_CHANNEL_REQUEST);
391: packet_put_int(c->remote_id);
392: packet_put_cstring("eow@openssh.com");
393: packet_put_char(0);
394: packet_send();
1.1 markus 395: }
1.23 markus 396:
397: /* shared */
398:
1.24 markus 399: void
1.42 markus 400: chan_rcvd_ieof(Channel *c)
401: {
402: if (compat20)
403: chan_rcvd_eof2(c);
404: else
405: chan_rcvd_ieof1(c);
1.44 markus 406: if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN &&
1.47 deraadt 407: buffer_len(&c->output) == 0 &&
1.45 markus 408: !CHANNEL_EFD_OUTPUT_ACTIVE(c))
1.44 markus 409: chan_obuf_empty(c);
1.42 markus 410: }
411: void
412: chan_rcvd_oclose(Channel *c)
413: {
414: if (compat20)
415: chan_rcvd_close2(c);
416: else
417: chan_rcvd_oclose1(c);
418: }
419: void
420: chan_write_failed(Channel *c)
421: {
422: if (compat20)
423: chan_write_failed2(c);
424: else
425: chan_write_failed1(c);
426: }
427:
428: void
1.24 markus 429: chan_mark_dead(Channel *c)
430: {
1.26 markus 431: c->type = SSH_CHANNEL_ZOMBIE;
1.24 markus 432: }
433:
1.23 markus 434: int
1.50 avsm 435: chan_is_dead(Channel *c, int do_send)
1.6 markus 436: {
1.26 markus 437: if (c->type == SSH_CHANNEL_ZOMBIE) {
1.49 markus 438: debug2("channel %d: zombie", c->self);
1.24 markus 439: return 1;
1.26 markus 440: }
1.23 markus 441: if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
442: return 0;
443: if (!compat20) {
1.49 markus 444: debug2("channel %d: is dead", c->self);
1.23 markus 445: return 1;
446: }
1.45 markus 447: if ((datafellows & SSH_BUG_EXTEOF) &&
448: c->extended_usage == CHAN_EXTENDED_WRITE &&
449: c->efd != -1 &&
450: buffer_len(&c->extended) > 0) {
1.46 markus 451: debug2("channel %d: active efd: %d len %d",
452: c->self, c->efd, buffer_len(&c->extended));
1.45 markus 453: return 0;
454: }
455: if (!(c->flags & CHAN_CLOSE_SENT)) {
1.50 avsm 456: if (do_send) {
1.45 markus 457: chan_send_close2(c);
458: } else {
459: /* channel would be dead if we sent a close */
460: if (c->flags & CHAN_CLOSE_RCVD) {
1.49 markus 461: debug2("channel %d: almost dead",
1.45 markus 462: c->self);
463: return 1;
1.32 markus 464: }
1.13 markus 465: }
1.45 markus 466: }
467: if ((c->flags & CHAN_CLOSE_SENT) &&
468: (c->flags & CHAN_CLOSE_RCVD)) {
1.49 markus 469: debug2("channel %d: is dead", c->self);
1.45 markus 470: return 1;
1.1 markus 471: }
1.23 markus 472: return 0;
1.13 markus 473: }
474:
475: /* helper */
476: static void
477: chan_shutdown_write(Channel *c)
478: {
1.34 markus 479: buffer_clear(&c->output);
1.13 markus 480: if (compat20 && c->type == SSH_CHANNEL_LARVAL)
481: return;
482: /* shutdown failure is allowed if write failed already */
1.49 markus 483: debug2("channel %d: close_write", c->self);
1.13 markus 484: if (c->sock != -1) {
485: if (shutdown(c->sock, SHUT_WR) < 0)
1.49 markus 486: debug2("channel %d: chan_shutdown_write: "
1.28 markus 487: "shutdown() failed for fd%d: %.100s",
1.13 markus 488: c->self, c->sock, strerror(errno));
489: } else {
1.31 markus 490: if (channel_close_fd(&c->wfd) < 0)
1.48 itojun 491: logit("channel %d: chan_shutdown_write: "
1.28 markus 492: "close() failed for fd%d: %.100s",
1.13 markus 493: c->self, c->wfd, strerror(errno));
494: }
495: }
496: static void
497: chan_shutdown_read(Channel *c)
498: {
499: if (compat20 && c->type == SSH_CHANNEL_LARVAL)
500: return;
1.49 markus 501: debug2("channel %d: close_read", c->self);
1.13 markus 502: if (c->sock != -1) {
503: if (shutdown(c->sock, SHUT_RD) < 0)
1.28 markus 504: error("channel %d: chan_shutdown_read: "
505: "shutdown() failed for fd%d [i%d o%d]: %.100s",
506: c->self, c->sock, c->istate, c->ostate,
507: strerror(errno));
1.13 markus 508: } else {
1.31 markus 509: if (channel_close_fd(&c->rfd) < 0)
1.48 itojun 510: logit("channel %d: chan_shutdown_read: "
1.28 markus 511: "close() failed for fd%d: %.100s",
1.13 markus 512: c->self, c->rfd, strerror(errno));
513: }
1.1 markus 514: }
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