mirror of git://anongit.mindrot.org/openssh.git
532 lines
13 KiB
C
532 lines
13 KiB
C
/* $OpenBSD: nchan.c,v 1.63 2010/01/26 01:28:35 djm Exp $ */
|
|
/*
|
|
* Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
|
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
#include "includes.h"
|
|
|
|
#include <sys/types.h>
|
|
#include <sys/socket.h>
|
|
|
|
#include <errno.h>
|
|
#include <string.h>
|
|
#include <stdarg.h>
|
|
|
|
#include "openbsd-compat/sys-queue.h"
|
|
#include "ssh1.h"
|
|
#include "ssh2.h"
|
|
#include "buffer.h"
|
|
#include "packet.h"
|
|
#include "channels.h"
|
|
#include "compat.h"
|
|
#include "log.h"
|
|
|
|
/*
|
|
* SSH Protocol 1.5 aka New Channel Protocol
|
|
* Thanks to Martina, Axel and everyone who left Erlangen, leaving me bored.
|
|
* Written by Markus Friedl in October 1999
|
|
*
|
|
* Protocol versions 1.3 and 1.5 differ in the handshake protocol used for the
|
|
* tear down of channels:
|
|
*
|
|
* 1.3: strict request-ack-protocol:
|
|
* CLOSE ->
|
|
* <- CLOSE_CONFIRM
|
|
*
|
|
* 1.5: uses variations of:
|
|
* IEOF ->
|
|
* <- OCLOSE
|
|
* <- IEOF
|
|
* OCLOSE ->
|
|
* i.e. both sides have to close the channel
|
|
*
|
|
* 2.0: the EOF messages are optional
|
|
*
|
|
* See the debugging output from 'ssh -v' and 'sshd -d' of
|
|
* ssh-1.2.27 as an example.
|
|
*
|
|
*/
|
|
|
|
/* functions manipulating channel states */
|
|
/*
|
|
* EVENTS update channel input/output states execute ACTIONS
|
|
*/
|
|
/*
|
|
* ACTIONS: should never update the channel states
|
|
*/
|
|
static void chan_send_ieof1(Channel *);
|
|
static void chan_send_oclose1(Channel *);
|
|
static void chan_send_close2(Channel *);
|
|
static void chan_send_eof2(Channel *);
|
|
static void chan_send_eow2(Channel *);
|
|
|
|
/* helper */
|
|
static void chan_shutdown_write(Channel *);
|
|
static void chan_shutdown_read(Channel *);
|
|
|
|
static char *ostates[] = { "open", "drain", "wait_ieof", "closed" };
|
|
static char *istates[] = { "open", "drain", "wait_oclose", "closed" };
|
|
|
|
static void
|
|
chan_set_istate(Channel *c, u_int next)
|
|
{
|
|
if (c->istate > CHAN_INPUT_CLOSED || next > CHAN_INPUT_CLOSED)
|
|
fatal("chan_set_istate: bad state %d -> %d", c->istate, next);
|
|
debug2("channel %d: input %s -> %s", c->self, istates[c->istate],
|
|
istates[next]);
|
|
c->istate = next;
|
|
}
|
|
static void
|
|
chan_set_ostate(Channel *c, u_int next)
|
|
{
|
|
if (c->ostate > CHAN_OUTPUT_CLOSED || next > CHAN_OUTPUT_CLOSED)
|
|
fatal("chan_set_ostate: bad state %d -> %d", c->ostate, next);
|
|
debug2("channel %d: output %s -> %s", c->self, ostates[c->ostate],
|
|
ostates[next]);
|
|
c->ostate = next;
|
|
}
|
|
|
|
/*
|
|
* SSH1 specific implementation of event functions
|
|
*/
|
|
|
|
static void
|
|
chan_rcvd_oclose1(Channel *c)
|
|
{
|
|
debug2("channel %d: rcvd oclose", c->self);
|
|
switch (c->istate) {
|
|
case CHAN_INPUT_WAIT_OCLOSE:
|
|
chan_set_istate(c, CHAN_INPUT_CLOSED);
|
|
break;
|
|
case CHAN_INPUT_OPEN:
|
|
chan_shutdown_read(c);
|
|
chan_send_ieof1(c);
|
|
chan_set_istate(c, CHAN_INPUT_CLOSED);
|
|
break;
|
|
case CHAN_INPUT_WAIT_DRAIN:
|
|
/* both local read_failed and remote write_failed */
|
|
chan_send_ieof1(c);
|
|
chan_set_istate(c, CHAN_INPUT_CLOSED);
|
|
break;
|
|
default:
|
|
error("channel %d: protocol error: rcvd_oclose for istate %d",
|
|
c->self, c->istate);
|
|
return;
|
|
}
|
|
}
|
|
void
|
|
chan_read_failed(Channel *c)
|
|
{
|
|
debug2("channel %d: read failed", c->self);
|
|
switch (c->istate) {
|
|
case CHAN_INPUT_OPEN:
|
|
chan_shutdown_read(c);
|
|
chan_set_istate(c, CHAN_INPUT_WAIT_DRAIN);
|
|
break;
|
|
default:
|
|
error("channel %d: chan_read_failed for istate %d",
|
|
c->self, c->istate);
|
|
break;
|
|
}
|
|
}
|
|
void
|
|
chan_ibuf_empty(Channel *c)
|
|
{
|
|
debug2("channel %d: ibuf empty", c->self);
|
|
if (buffer_len(&c->input)) {
|
|
error("channel %d: chan_ibuf_empty for non empty buffer",
|
|
c->self);
|
|
return;
|
|
}
|
|
switch (c->istate) {
|
|
case CHAN_INPUT_WAIT_DRAIN:
|
|
if (compat20) {
|
|
if (!(c->flags & (CHAN_CLOSE_SENT|CHAN_LOCAL)))
|
|
chan_send_eof2(c);
|
|
chan_set_istate(c, CHAN_INPUT_CLOSED);
|
|
} else {
|
|
chan_send_ieof1(c);
|
|
chan_set_istate(c, CHAN_INPUT_WAIT_OCLOSE);
|
|
}
|
|
break;
|
|
default:
|
|
error("channel %d: chan_ibuf_empty for istate %d",
|
|
c->self, c->istate);
|
|
break;
|
|
}
|
|
}
|
|
static void
|
|
chan_rcvd_ieof1(Channel *c)
|
|
{
|
|
debug2("channel %d: rcvd ieof", c->self);
|
|
switch (c->ostate) {
|
|
case CHAN_OUTPUT_OPEN:
|
|
chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
|
|
break;
|
|
case CHAN_OUTPUT_WAIT_IEOF:
|
|
chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
|
|
break;
|
|
default:
|
|
error("channel %d: protocol error: rcvd_ieof for ostate %d",
|
|
c->self, c->ostate);
|
|
break;
|
|
}
|
|
}
|
|
static void
|
|
chan_write_failed1(Channel *c)
|
|
{
|
|
debug2("channel %d: write failed", c->self);
|
|
switch (c->ostate) {
|
|
case CHAN_OUTPUT_OPEN:
|
|
chan_shutdown_write(c);
|
|
chan_send_oclose1(c);
|
|
chan_set_ostate(c, CHAN_OUTPUT_WAIT_IEOF);
|
|
break;
|
|
case CHAN_OUTPUT_WAIT_DRAIN:
|
|
chan_shutdown_write(c);
|
|
chan_send_oclose1(c);
|
|
chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
|
|
break;
|
|
default:
|
|
error("channel %d: chan_write_failed for ostate %d",
|
|
c->self, c->ostate);
|
|
break;
|
|
}
|
|
}
|
|
void
|
|
chan_obuf_empty(Channel *c)
|
|
{
|
|
debug2("channel %d: obuf empty", c->self);
|
|
if (buffer_len(&c->output)) {
|
|
error("channel %d: chan_obuf_empty for non empty buffer",
|
|
c->self);
|
|
return;
|
|
}
|
|
switch (c->ostate) {
|
|
case CHAN_OUTPUT_WAIT_DRAIN:
|
|
chan_shutdown_write(c);
|
|
if (!compat20)
|
|
chan_send_oclose1(c);
|
|
chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
|
|
break;
|
|
default:
|
|
error("channel %d: internal error: obuf_empty for ostate %d",
|
|
c->self, c->ostate);
|
|
break;
|
|
}
|
|
}
|
|
static void
|
|
chan_send_ieof1(Channel *c)
|
|
{
|
|
debug2("channel %d: send ieof", c->self);
|
|
switch (c->istate) {
|
|
case CHAN_INPUT_OPEN:
|
|
case CHAN_INPUT_WAIT_DRAIN:
|
|
packet_start(SSH_MSG_CHANNEL_INPUT_EOF);
|
|
packet_put_int(c->remote_id);
|
|
packet_send();
|
|
break;
|
|
default:
|
|
error("channel %d: cannot send ieof for istate %d",
|
|
c->self, c->istate);
|
|
break;
|
|
}
|
|
}
|
|
static void
|
|
chan_send_oclose1(Channel *c)
|
|
{
|
|
debug2("channel %d: send oclose", c->self);
|
|
switch (c->ostate) {
|
|
case CHAN_OUTPUT_OPEN:
|
|
case CHAN_OUTPUT_WAIT_DRAIN:
|
|
buffer_clear(&c->output);
|
|
packet_start(SSH_MSG_CHANNEL_OUTPUT_CLOSE);
|
|
packet_put_int(c->remote_id);
|
|
packet_send();
|
|
break;
|
|
default:
|
|
error("channel %d: cannot send oclose for ostate %d",
|
|
c->self, c->ostate);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* the same for SSH2
|
|
*/
|
|
static void
|
|
chan_rcvd_close2(Channel *c)
|
|
{
|
|
debug2("channel %d: rcvd close", c->self);
|
|
if (!(c->flags & CHAN_LOCAL)) {
|
|
if (c->flags & CHAN_CLOSE_RCVD)
|
|
error("channel %d: protocol error: close rcvd twice",
|
|
c->self);
|
|
c->flags |= CHAN_CLOSE_RCVD;
|
|
}
|
|
if (c->type == SSH_CHANNEL_LARVAL) {
|
|
/* tear down larval channels immediately */
|
|
chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
|
|
chan_set_istate(c, CHAN_INPUT_CLOSED);
|
|
return;
|
|
}
|
|
switch (c->ostate) {
|
|
case CHAN_OUTPUT_OPEN:
|
|
/*
|
|
* wait until a data from the channel is consumed if a CLOSE
|
|
* is received
|
|
*/
|
|
chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
|
|
break;
|
|
}
|
|
switch (c->istate) {
|
|
case CHAN_INPUT_OPEN:
|
|
chan_shutdown_read(c);
|
|
chan_set_istate(c, CHAN_INPUT_CLOSED);
|
|
break;
|
|
case CHAN_INPUT_WAIT_DRAIN:
|
|
if (!(c->flags & CHAN_LOCAL))
|
|
chan_send_eof2(c);
|
|
chan_set_istate(c, CHAN_INPUT_CLOSED);
|
|
break;
|
|
}
|
|
}
|
|
|
|
void
|
|
chan_rcvd_eow(Channel *c)
|
|
{
|
|
debug2("channel %d: rcvd eow", c->self);
|
|
switch (c->istate) {
|
|
case CHAN_INPUT_OPEN:
|
|
chan_shutdown_read(c);
|
|
chan_set_istate(c, CHAN_INPUT_CLOSED);
|
|
break;
|
|
}
|
|
}
|
|
static void
|
|
chan_rcvd_eof2(Channel *c)
|
|
{
|
|
debug2("channel %d: rcvd eof", c->self);
|
|
c->flags |= CHAN_EOF_RCVD;
|
|
if (c->ostate == CHAN_OUTPUT_OPEN)
|
|
chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
|
|
}
|
|
static void
|
|
chan_write_failed2(Channel *c)
|
|
{
|
|
debug2("channel %d: write failed", c->self);
|
|
switch (c->ostate) {
|
|
case CHAN_OUTPUT_OPEN:
|
|
case CHAN_OUTPUT_WAIT_DRAIN:
|
|
chan_shutdown_write(c);
|
|
if (strcmp(c->ctype, "session") == 0)
|
|
chan_send_eow2(c);
|
|
chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
|
|
break;
|
|
default:
|
|
error("channel %d: chan_write_failed for ostate %d",
|
|
c->self, c->ostate);
|
|
break;
|
|
}
|
|
}
|
|
static void
|
|
chan_send_eof2(Channel *c)
|
|
{
|
|
debug2("channel %d: send eof", c->self);
|
|
switch (c->istate) {
|
|
case CHAN_INPUT_WAIT_DRAIN:
|
|
packet_start(SSH2_MSG_CHANNEL_EOF);
|
|
packet_put_int(c->remote_id);
|
|
packet_send();
|
|
c->flags |= CHAN_EOF_SENT;
|
|
break;
|
|
default:
|
|
error("channel %d: cannot send eof for istate %d",
|
|
c->self, c->istate);
|
|
break;
|
|
}
|
|
}
|
|
static void
|
|
chan_send_close2(Channel *c)
|
|
{
|
|
debug2("channel %d: send close", c->self);
|
|
if (c->ostate != CHAN_OUTPUT_CLOSED ||
|
|
c->istate != CHAN_INPUT_CLOSED) {
|
|
error("channel %d: cannot send close for istate/ostate %d/%d",
|
|
c->self, c->istate, c->ostate);
|
|
} else if (c->flags & CHAN_CLOSE_SENT) {
|
|
error("channel %d: already sent close", c->self);
|
|
} else {
|
|
packet_start(SSH2_MSG_CHANNEL_CLOSE);
|
|
packet_put_int(c->remote_id);
|
|
packet_send();
|
|
c->flags |= CHAN_CLOSE_SENT;
|
|
}
|
|
}
|
|
static void
|
|
chan_send_eow2(Channel *c)
|
|
{
|
|
debug2("channel %d: send eow", c->self);
|
|
if (c->ostate == CHAN_OUTPUT_CLOSED) {
|
|
error("channel %d: must not sent eow on closed output",
|
|
c->self);
|
|
return;
|
|
}
|
|
if (!(datafellows & SSH_NEW_OPENSSH))
|
|
return;
|
|
packet_start(SSH2_MSG_CHANNEL_REQUEST);
|
|
packet_put_int(c->remote_id);
|
|
packet_put_cstring("eow@openssh.com");
|
|
packet_put_char(0);
|
|
packet_send();
|
|
}
|
|
|
|
/* shared */
|
|
|
|
void
|
|
chan_rcvd_ieof(Channel *c)
|
|
{
|
|
if (compat20)
|
|
chan_rcvd_eof2(c);
|
|
else
|
|
chan_rcvd_ieof1(c);
|
|
if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN &&
|
|
buffer_len(&c->output) == 0 &&
|
|
!CHANNEL_EFD_OUTPUT_ACTIVE(c))
|
|
chan_obuf_empty(c);
|
|
}
|
|
void
|
|
chan_rcvd_oclose(Channel *c)
|
|
{
|
|
if (compat20)
|
|
chan_rcvd_close2(c);
|
|
else
|
|
chan_rcvd_oclose1(c);
|
|
}
|
|
void
|
|
chan_write_failed(Channel *c)
|
|
{
|
|
if (compat20)
|
|
chan_write_failed2(c);
|
|
else
|
|
chan_write_failed1(c);
|
|
}
|
|
|
|
void
|
|
chan_mark_dead(Channel *c)
|
|
{
|
|
c->type = SSH_CHANNEL_ZOMBIE;
|
|
}
|
|
|
|
int
|
|
chan_is_dead(Channel *c, int do_send)
|
|
{
|
|
if (c->type == SSH_CHANNEL_ZOMBIE) {
|
|
debug2("channel %d: zombie", c->self);
|
|
return 1;
|
|
}
|
|
if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
|
|
return 0;
|
|
if (!compat20) {
|
|
debug2("channel %d: is dead", c->self);
|
|
return 1;
|
|
}
|
|
if ((datafellows & SSH_BUG_EXTEOF) &&
|
|
c->extended_usage == CHAN_EXTENDED_WRITE &&
|
|
c->efd != -1 &&
|
|
buffer_len(&c->extended) > 0) {
|
|
debug2("channel %d: active efd: %d len %d",
|
|
c->self, c->efd, buffer_len(&c->extended));
|
|
return 0;
|
|
}
|
|
if (c->flags & CHAN_LOCAL) {
|
|
debug2("channel %d: is dead (local)", c->self);
|
|
return 1;
|
|
}
|
|
if (!(c->flags & CHAN_CLOSE_SENT)) {
|
|
if (do_send) {
|
|
chan_send_close2(c);
|
|
} else {
|
|
/* channel would be dead if we sent a close */
|
|
if (c->flags & CHAN_CLOSE_RCVD) {
|
|
debug2("channel %d: almost dead",
|
|
c->self);
|
|
return 1;
|
|
}
|
|
}
|
|
}
|
|
if ((c->flags & CHAN_CLOSE_SENT) &&
|
|
(c->flags & CHAN_CLOSE_RCVD)) {
|
|
debug2("channel %d: is dead", c->self);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* helper */
|
|
static void
|
|
chan_shutdown_write(Channel *c)
|
|
{
|
|
buffer_clear(&c->output);
|
|
if (compat20 && c->type == SSH_CHANNEL_LARVAL)
|
|
return;
|
|
/* shutdown failure is allowed if write failed already */
|
|
debug2("channel %d: close_write", c->self);
|
|
if (c->sock != -1) {
|
|
if (shutdown(c->sock, SHUT_WR) < 0)
|
|
debug2("channel %d: chan_shutdown_write: "
|
|
"shutdown() failed for fd %d: %.100s",
|
|
c->self, c->sock, strerror(errno));
|
|
} else {
|
|
if (channel_close_fd(&c->wfd) < 0)
|
|
logit("channel %d: chan_shutdown_write: "
|
|
"close() failed for fd %d: %.100s",
|
|
c->self, c->wfd, strerror(errno));
|
|
}
|
|
}
|
|
static void
|
|
chan_shutdown_read(Channel *c)
|
|
{
|
|
if (compat20 && c->type == SSH_CHANNEL_LARVAL)
|
|
return;
|
|
debug2("channel %d: close_read", c->self);
|
|
if (c->sock != -1) {
|
|
/*
|
|
* shutdown(sock, SHUT_READ) may return ENOTCONN if the
|
|
* write side has been closed already. (bug on Linux)
|
|
* HP-UX may return ENOTCONN also.
|
|
*/
|
|
if (shutdown(c->sock, SHUT_RD) < 0
|
|
&& errno != ENOTCONN)
|
|
error("channel %d: chan_shutdown_read: "
|
|
"shutdown() failed for fd %d [i%d o%d]: %.100s",
|
|
c->self, c->sock, c->istate, c->ostate,
|
|
strerror(errno));
|
|
} else {
|
|
if (channel_close_fd(&c->rfd) < 0)
|
|
logit("channel %d: chan_shutdown_read: "
|
|
"close() failed for fd %d: %.100s",
|
|
c->self, c->rfd, strerror(errno));
|
|
}
|
|
}
|