Annotation of src/usr.bin/ssh/nchan.c, Revision 1.67
1.67 ! djm 1: /* $OpenBSD: nchan.c,v 1.66 2017/09/12 06:32:07 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 "ssh2.h"
1.66 djm 35: #include "sshbuf.h"
36: #include "ssherr.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: */
1.66 djm 75: static void chan_send_eof2(struct ssh *, Channel *);
76: static void chan_send_eow2(struct ssh *, Channel *);
1.13 markus 77:
78: /* helper */
1.66 djm 79: static void chan_shutdown_write(struct ssh *, Channel *);
80: static void chan_shutdown_read(struct ssh *, Channel *);
1.13 markus 81:
1.66 djm 82: static const char *ostates[] = { "open", "drain", "wait_ieof", "closed" };
83: static const char *istates[] = { "open", "drain", "wait_oclose", "closed" };
1.37 markus 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);
1.49 markus 90: debug2("channel %d: input %s -> %s", c->self, istates[c->istate],
1.37 markus 91: istates[next]);
92: c->istate = next;
93: }
1.64 djm 94:
1.37 markus 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);
1.49 markus 100: debug2("channel %d: output %s -> %s", c->self, ostates[c->ostate],
1.37 markus 101: ostates[next]);
102: c->ostate = next;
103: }
104:
1.42 markus 105: void
1.66 djm 106: chan_read_failed(struct ssh *ssh, Channel *c)
1.6 markus 107: {
1.49 markus 108: debug2("channel %d: read failed", c->self);
1.6 markus 109: switch (c->istate) {
1.3 markus 110: case CHAN_INPUT_OPEN:
1.66 djm 111: chan_shutdown_read(ssh, c);
1.37 markus 112: chan_set_istate(c, CHAN_INPUT_WAIT_DRAIN);
1.3 markus 113: break;
114: default:
1.28 markus 115: error("channel %d: chan_read_failed for istate %d",
1.13 markus 116: c->self, c->istate);
1.3 markus 117: break;
1.1 markus 118: }
119: }
1.64 djm 120:
1.42 markus 121: void
1.66 djm 122: chan_ibuf_empty(struct ssh *ssh, Channel *c)
1.6 markus 123: {
1.49 markus 124: debug2("channel %d: ibuf empty", c->self);
1.66 djm 125: if (sshbuf_len(c->input)) {
1.28 markus 126: error("channel %d: chan_ibuf_empty for non empty buffer",
1.13 markus 127: c->self);
1.3 markus 128: return;
129: }
1.6 markus 130: switch (c->istate) {
1.3 markus 131: case CHAN_INPUT_WAIT_DRAIN:
1.64 djm 132: if (!(c->flags & (CHAN_CLOSE_SENT|CHAN_LOCAL)))
1.66 djm 133: chan_send_eof2(ssh, c);
1.64 djm 134: chan_set_istate(c, CHAN_INPUT_CLOSED);
1.3 markus 135: break;
136: default:
1.28 markus 137: error("channel %d: chan_ibuf_empty for istate %d",
1.13 markus 138: c->self, c->istate);
1.3 markus 139: break;
1.1 markus 140: }
141: }
1.64 djm 142:
1.42 markus 143: void
1.66 djm 144: chan_obuf_empty(struct ssh *ssh, Channel *c)
1.6 markus 145: {
1.49 markus 146: debug2("channel %d: obuf empty", c->self);
1.66 djm 147: if (sshbuf_len(c->output)) {
1.28 markus 148: error("channel %d: chan_obuf_empty for non empty buffer",
1.13 markus 149: c->self);
1.3 markus 150: return;
151: }
1.6 markus 152: switch (c->ostate) {
1.3 markus 153: case CHAN_OUTPUT_WAIT_DRAIN:
1.66 djm 154: chan_shutdown_write(ssh, c);
1.37 markus 155: chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
1.3 markus 156: break;
157: default:
1.28 markus 158: error("channel %d: internal error: obuf_empty for ostate %d",
1.13 markus 159: c->self, c->ostate);
1.3 markus 160: break;
161: }
162: }
1.63 djm 163:
1.59 markus 164: void
1.66 djm 165: chan_rcvd_eow(struct ssh *ssh, Channel *c)
1.59 markus 166: {
167: debug2("channel %d: rcvd eow", c->self);
168: switch (c->istate) {
169: case CHAN_INPUT_OPEN:
1.66 djm 170: chan_shutdown_read(ssh, c);
1.59 markus 171: chan_set_istate(c, CHAN_INPUT_CLOSED);
172: break;
173: }
174: }
1.64 djm 175:
1.13 markus 176: static void
1.66 djm 177: chan_send_eof2(struct ssh *ssh, Channel *c)
1.6 markus 178: {
1.66 djm 179: int r;
180:
1.49 markus 181: debug2("channel %d: send eof", c->self);
1.13 markus 182: switch (c->istate) {
183: case CHAN_INPUT_WAIT_DRAIN:
1.67 ! djm 184: if (!c->have_remote_id)
! 185: fatal("%s: channel %d: no remote_id",
! 186: __func__, c->self);
1.66 djm 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));
1.45 markus 191: c->flags |= CHAN_EOF_SENT;
1.13 markus 192: break;
193: default:
1.28 markus 194: error("channel %d: cannot send eof for istate %d",
1.13 markus 195: c->self, c->istate);
196: break;
197: }
1.1 markus 198: }
1.64 djm 199:
1.3 markus 200: static void
1.66 djm 201: chan_send_close2(struct ssh *ssh, Channel *c)
1.6 markus 202: {
1.66 djm 203: int r;
204:
1.49 markus 205: debug2("channel %d: send close", c->self);
1.13 markus 206: if (c->ostate != CHAN_OUTPUT_CLOSED ||
207: c->istate != CHAN_INPUT_CLOSED) {
1.28 markus 208: error("channel %d: cannot send close for istate/ostate %d/%d",
1.13 markus 209: c->self, c->istate, c->ostate);
210: } else if (c->flags & CHAN_CLOSE_SENT) {
1.28 markus 211: error("channel %d: already sent close", c->self);
1.13 markus 212: } else {
1.67 ! djm 213: if (!c->have_remote_id)
! 214: fatal("%s: channel %d: no remote_id",
! 215: __func__, c->self);
1.66 djm 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));
1.13 markus 220: c->flags |= CHAN_CLOSE_SENT;
221: }
1.59 markus 222: }
1.64 djm 223:
1.59 markus 224: static void
1.66 djm 225: chan_send_eow2(struct ssh *ssh, Channel *c)
1.59 markus 226: {
1.66 djm 227: int r;
228:
1.59 markus 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: }
1.61 markus 235: if (!(datafellows & SSH_NEW_OPENSSH))
236: return;
1.67 ! djm 237: if (!c->have_remote_id)
! 238: fatal("%s: channel %d: no remote_id", __func__, c->self);
1.66 djm 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));
1.1 markus 245: }
1.23 markus 246:
247: /* shared */
248:
1.24 markus 249: void
1.66 djm 250: chan_rcvd_ieof(struct ssh *ssh, Channel *c)
1.42 markus 251: {
1.64 djm 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);
1.44 markus 256: if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN &&
1.66 djm 257: sshbuf_len(c->output) == 0 &&
1.45 markus 258: !CHANNEL_EFD_OUTPUT_ACTIVE(c))
1.66 djm 259: chan_obuf_empty(ssh, c);
1.42 markus 260: }
1.64 djm 261:
1.42 markus 262: void
1.66 djm 263: chan_rcvd_oclose(struct ssh *ssh, Channel *c)
1.42 markus 264: {
1.64 djm 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:
1.66 djm 289: chan_shutdown_read(ssh, c);
1.64 djm 290: chan_set_istate(c, CHAN_INPUT_CLOSED);
291: break;
292: case CHAN_INPUT_WAIT_DRAIN:
293: if (!(c->flags & CHAN_LOCAL))
1.66 djm 294: chan_send_eof2(ssh, c);
1.64 djm 295: chan_set_istate(c, CHAN_INPUT_CLOSED);
296: break;
297: }
1.42 markus 298: }
1.64 djm 299:
1.42 markus 300: void
1.66 djm 301: chan_write_failed(struct ssh *ssh, Channel *c)
1.42 markus 302: {
1.64 djm 303: debug2("channel %d: write failed", c->self);
304: switch (c->ostate) {
305: case CHAN_OUTPUT_OPEN:
306: case CHAN_OUTPUT_WAIT_DRAIN:
1.66 djm 307: chan_shutdown_write(ssh, c);
1.64 djm 308: if (strcmp(c->ctype, "session") == 0)
1.66 djm 309: chan_send_eow2(ssh, c);
1.64 djm 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: }
1.42 markus 317: }
318:
319: void
1.66 djm 320: chan_mark_dead(struct ssh *ssh, Channel *c)
1.24 markus 321: {
1.26 markus 322: c->type = SSH_CHANNEL_ZOMBIE;
1.24 markus 323: }
324:
1.23 markus 325: int
1.66 djm 326: chan_is_dead(struct ssh *ssh, Channel *c, int do_send)
1.6 markus 327: {
1.26 markus 328: if (c->type == SSH_CHANNEL_ZOMBIE) {
1.49 markus 329: debug2("channel %d: zombie", c->self);
1.24 markus 330: return 1;
1.26 markus 331: }
1.23 markus 332: if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
333: return 0;
1.45 markus 334: if ((datafellows & SSH_BUG_EXTEOF) &&
335: c->extended_usage == CHAN_EXTENDED_WRITE &&
336: c->efd != -1 &&
1.66 djm 337: sshbuf_len(c->extended) > 0) {
338: debug2("channel %d: active efd: %d len %zu",
339: c->self, c->efd, sshbuf_len(c->extended));
1.45 markus 340: return 0;
341: }
1.63 djm 342: if (c->flags & CHAN_LOCAL) {
343: debug2("channel %d: is dead (local)", c->self);
344: return 1;
345: }
1.45 markus 346: if (!(c->flags & CHAN_CLOSE_SENT)) {
1.50 avsm 347: if (do_send) {
1.66 djm 348: chan_send_close2(ssh, c);
1.45 markus 349: } else {
350: /* channel would be dead if we sent a close */
351: if (c->flags & CHAN_CLOSE_RCVD) {
1.49 markus 352: debug2("channel %d: almost dead",
1.45 markus 353: c->self);
354: return 1;
1.32 markus 355: }
1.13 markus 356: }
1.45 markus 357: }
358: if ((c->flags & CHAN_CLOSE_SENT) &&
359: (c->flags & CHAN_CLOSE_RCVD)) {
1.49 markus 360: debug2("channel %d: is dead", c->self);
1.45 markus 361: return 1;
1.1 markus 362: }
1.23 markus 363: return 0;
1.13 markus 364: }
365:
366: /* helper */
367: static void
1.66 djm 368: chan_shutdown_write(struct ssh *ssh, Channel *c)
1.13 markus 369: {
1.66 djm 370: sshbuf_reset(c->output);
1.64 djm 371: if (c->type == SSH_CHANNEL_LARVAL)
1.13 markus 372: return;
373: /* shutdown failure is allowed if write failed already */
1.49 markus 374: debug2("channel %d: close_write", c->self);
1.13 markus 375: if (c->sock != -1) {
376: if (shutdown(c->sock, SHUT_WR) < 0)
1.49 markus 377: debug2("channel %d: chan_shutdown_write: "
1.62 stevesk 378: "shutdown() failed for fd %d: %.100s",
1.13 markus 379: c->self, c->sock, strerror(errno));
380: } else {
1.66 djm 381: if (channel_close_fd(ssh, &c->wfd) < 0)
1.48 itojun 382: logit("channel %d: chan_shutdown_write: "
1.62 stevesk 383: "close() failed for fd %d: %.100s",
1.13 markus 384: c->self, c->wfd, strerror(errno));
385: }
386: }
1.64 djm 387:
1.13 markus 388: static void
1.66 djm 389: chan_shutdown_read(struct ssh *ssh, Channel *c)
1.13 markus 390: {
1.64 djm 391: if (c->type == SSH_CHANNEL_LARVAL)
1.13 markus 392: return;
1.49 markus 393: debug2("channel %d: close_read", c->self);
1.13 markus 394: if (c->sock != -1) {
395: if (shutdown(c->sock, SHUT_RD) < 0)
1.28 markus 396: error("channel %d: chan_shutdown_read: "
1.62 stevesk 397: "shutdown() failed for fd %d [i%d o%d]: %.100s",
1.28 markus 398: c->self, c->sock, c->istate, c->ostate,
399: strerror(errno));
1.13 markus 400: } else {
1.66 djm 401: if (channel_close_fd(ssh, &c->rfd) < 0)
1.48 itojun 402: logit("channel %d: chan_shutdown_read: "
1.62 stevesk 403: "close() failed for fd %d: %.100s",
1.13 markus 404: c->self, c->rfd, strerror(errno));
405: }
1.1 markus 406: }
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