openssh/nchan.c
Damien Miller 9f0f5c64bc - deraadt@cvs.openbsd.org 2001/12/19 07:18:56
[auth1.c auth2.c auth2-chall.c auth-bsdauth.c auth.c authfile.c auth.h]
     [auth-krb4.c auth-rhosts.c auth-skey.c bufaux.c canohost.c channels.c]
     [cipher.c clientloop.c compat.c compress.c deattack.c key.c log.c mac.c]
     [match.c misc.c nchan.c packet.c readconf.c rijndael.c rijndael.h scard.c]
     [servconf.c servconf.h serverloop.c session.c sftp.c sftp-client.c]
     [sftp-glob.c sftp-int.c sftp-server.c ssh-add.c ssh-agent.c ssh.c]
     [sshconnect1.c sshconnect2.c sshconnect.c sshd.8 sshd.c sshd_config]
     [ssh-keygen.c sshlogin.c sshpty.c sshtty.c ttymodes.c uidswap.c]
     basic KNF done while i was looking for something else
2001-12-21 14:45:46 +11:00

561 lines
14 KiB
C

/*
* Copyright (c) 1999, 2000, 2001 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"
RCSID("$OpenBSD: nchan.c,v 1.33 2001/12/19 07:18:56 deraadt Exp $");
#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
*/
/* events concerning the INPUT from socket for channel (istate) */
chan_event_fn *chan_rcvd_oclose = NULL;
chan_event_fn *chan_read_failed = NULL;
chan_event_fn *chan_ibuf_empty = NULL;
/* events concerning the OUTPUT from channel for socket (ostate) */
chan_event_fn *chan_rcvd_ieof = NULL;
chan_event_fn *chan_write_failed = NULL;
chan_event_fn *chan_obuf_empty = NULL;
/*
* 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 *);
/* helper */
static void chan_shutdown_write(Channel *);
static void chan_shutdown_read(Channel *);
/*
* SSH1 specific implementation of event functions
*/
static void
chan_rcvd_oclose1(Channel *c)
{
debug("channel %d: rcvd oclose", c->self);
switch (c->istate) {
case CHAN_INPUT_WAIT_OCLOSE:
debug("channel %d: input wait_oclose -> closed", c->self);
c->istate = CHAN_INPUT_CLOSED;
break;
case CHAN_INPUT_OPEN:
debug("channel %d: input open -> closed", c->self);
chan_shutdown_read(c);
chan_send_ieof1(c);
c->istate = CHAN_INPUT_CLOSED;
break;
case CHAN_INPUT_WAIT_DRAIN:
/* both local read_failed and remote write_failed */
log("channel %d: input drain -> closed", c->self);
chan_send_ieof1(c);
c->istate = CHAN_INPUT_CLOSED;
break;
default:
error("channel %d: protocol error: rcvd_oclose for istate %d",
c->self, c->istate);
return;
}
}
static void
chan_read_failed_12(Channel *c)
{
debug("channel %d: read failed", c->self);
switch (c->istate) {
case CHAN_INPUT_OPEN:
debug("channel %d: input open -> drain", c->self);
chan_shutdown_read(c);
c->istate = CHAN_INPUT_WAIT_DRAIN;
#if 0
if (buffer_len(&c->input) == 0) {
debug("channel %d: input: no drain shortcut", c->self);
chan_ibuf_empty(c);
}
#endif
break;
default:
error("channel %d: chan_read_failed for istate %d",
c->self, c->istate);
break;
}
}
static void
chan_ibuf_empty1(Channel *c)
{
debug("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:
debug("channel %d: input drain -> wait_oclose", c->self);
chan_send_ieof1(c);
c->istate = 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)
{
debug("channel %d: rcvd ieof", c->self);
if (c->type != SSH_CHANNEL_OPEN) {
debug("channel %d: non-open", c->self);
if (c->istate == CHAN_INPUT_OPEN) {
debug("channel %d: non-open: input open -> wait_oclose",
c->self);
chan_shutdown_read(c);
chan_send_ieof1(c);
c->istate = CHAN_INPUT_WAIT_OCLOSE;
} else {
error("channel %d: non-open: istate %d != open",
c->self, c->istate);
}
if (c->ostate == CHAN_OUTPUT_OPEN) {
debug("channel %d: non-open: output open -> closed",
c->self);
chan_send_oclose1(c);
c->ostate = CHAN_OUTPUT_CLOSED;
} else {
error("channel %d: non-open: ostate %d != open",
c->self, c->ostate);
}
return;
}
switch (c->ostate) {
case CHAN_OUTPUT_OPEN:
debug("channel %d: output open -> drain", c->self);
c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
break;
case CHAN_OUTPUT_WAIT_IEOF:
debug("channel %d: output wait_ieof -> closed", c->self);
c->ostate = 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)
{
debug("channel %d: write failed", c->self);
switch (c->ostate) {
case CHAN_OUTPUT_OPEN:
debug("channel %d: output open -> wait_ieof", c->self);
chan_send_oclose1(c);
c->ostate = CHAN_OUTPUT_WAIT_IEOF;
break;
case CHAN_OUTPUT_WAIT_DRAIN:
debug("channel %d: output wait_drain -> closed", c->self);
chan_send_oclose1(c);
c->ostate = CHAN_OUTPUT_CLOSED;
break;
default:
error("channel %d: chan_write_failed for ostate %d",
c->self, c->ostate);
break;
}
}
static void
chan_obuf_empty1(Channel *c)
{
debug("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:
debug("channel %d: output drain -> closed", c->self);
chan_send_oclose1(c);
c->ostate = 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)
{
debug("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)
{
debug("channel %d: send oclose", c->self);
switch (c->ostate) {
case CHAN_OUTPUT_OPEN:
case CHAN_OUTPUT_WAIT_DRAIN:
chan_shutdown_write(c);
buffer_consume(&c->output, buffer_len(&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_oclose2(Channel *c)
{
debug("channel %d: rcvd close", c->self);
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 */
c->ostate = CHAN_OUTPUT_CLOSED;
c->istate = 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
*/
debug("channel %d: output open -> drain", c->self);
c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
break;
}
switch (c->istate) {
case CHAN_INPUT_OPEN:
debug("channel %d: input open -> closed", c->self);
chan_shutdown_read(c);
break;
case CHAN_INPUT_WAIT_DRAIN:
debug("channel %d: input drain -> closed", c->self);
chan_send_eof2(c);
break;
}
c->istate = CHAN_INPUT_CLOSED;
}
static void
chan_ibuf_empty2(Channel *c)
{
debug("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:
debug("channel %d: input drain -> closed", c->self);
if (!(c->flags & CHAN_CLOSE_SENT))
chan_send_eof2(c);
c->istate = CHAN_INPUT_CLOSED;
break;
default:
error("channel %d: chan_ibuf_empty for istate %d",
c->self, c->istate);
break;
}
}
static void
chan_rcvd_ieof2(Channel *c)
{
debug("channel %d: rcvd eof", c->self);
if (c->ostate == CHAN_OUTPUT_OPEN) {
debug("channel %d: output open -> drain", c->self);
c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
}
}
static void
chan_write_failed2(Channel *c)
{
debug("channel %d: write failed", c->self);
switch (c->ostate) {
case CHAN_OUTPUT_OPEN:
debug("channel %d: output open -> closed", c->self);
chan_shutdown_write(c); /* ?? */
c->ostate = CHAN_OUTPUT_CLOSED;
break;
case CHAN_OUTPUT_WAIT_DRAIN:
debug("channel %d: output drain -> closed", c->self);
chan_shutdown_write(c);
c->ostate = CHAN_OUTPUT_CLOSED;
break;
default:
error("channel %d: chan_write_failed for ostate %d",
c->self, c->ostate);
break;
}
}
static void
chan_obuf_empty2(Channel *c)
{
debug("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:
debug("channel %d: output drain -> closed", c->self);
chan_shutdown_write(c);
c->ostate = CHAN_OUTPUT_CLOSED;
break;
default:
error("channel %d: chan_obuf_empty for ostate %d",
c->self, c->ostate);
break;
}
}
static void
chan_send_eof2(Channel *c)
{
debug("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();
break;
default:
error("channel %d: cannot send eof for istate %d",
c->self, c->istate);
break;
}
}
static void
chan_send_close2(Channel *c)
{
debug("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;
}
}
/* shared */
void
chan_mark_dead(Channel *c)
{
c->type = SSH_CHANNEL_ZOMBIE;
}
int
chan_is_dead(Channel *c, int send)
{
if (c->type == SSH_CHANNEL_ZOMBIE) {
debug("channel %d: zombie", c->self);
return 1;
}
if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
return 0;
if (!compat20) {
debug("channel %d: is dead", c->self);
return 1;
}
/*
* we have to delay the close message if the efd (for stderr) is
* still active
*/
if (((c->extended_usage != CHAN_EXTENDED_IGNORE) &&
buffer_len(&c->extended) > 0)
#if 0
|| ((c->extended_usage == CHAN_EXTENDED_READ) &&
c->efd != -1)
#endif
) {
debug2("channel %d: active efd: %d len %d type %s",
c->self, c->efd, buffer_len(&c->extended),
c->extended_usage==CHAN_EXTENDED_READ ?
"read": "write");
} else {
if (!(c->flags & CHAN_CLOSE_SENT)) {
if (send) {
chan_send_close2(c);
} else {
/* channel would be dead if we sent a close */
if (c->flags & CHAN_CLOSE_RCVD) {
debug("channel %d: almost dead",
c->self);
return 1;
}
}
}
if ((c->flags & CHAN_CLOSE_SENT) &&
(c->flags & CHAN_CLOSE_RCVD)) {
debug("channel %d: is dead", c->self);
return 1;
}
}
return 0;
}
void
chan_init_iostates(Channel *c)
{
c->ostate = CHAN_OUTPUT_OPEN;
c->istate = CHAN_INPUT_OPEN;
c->flags = 0;
}
/* init */
void
chan_init(void)
{
if (compat20) {
chan_rcvd_oclose = chan_rcvd_oclose2;
chan_read_failed = chan_read_failed_12;
chan_ibuf_empty = chan_ibuf_empty2;
chan_rcvd_ieof = chan_rcvd_ieof2;
chan_write_failed = chan_write_failed2;
chan_obuf_empty = chan_obuf_empty2;
} else {
chan_rcvd_oclose = chan_rcvd_oclose1;
chan_read_failed = chan_read_failed_12;
chan_ibuf_empty = chan_ibuf_empty1;
chan_rcvd_ieof = chan_rcvd_ieof1;
chan_write_failed = chan_write_failed1;
chan_obuf_empty = chan_obuf_empty1;
}
}
/* helper */
static void
chan_shutdown_write(Channel *c)
{
buffer_consume(&c->output, buffer_len(&c->output));
if (compat20 && c->type == SSH_CHANNEL_LARVAL)
return;
/* shutdown failure is allowed if write failed already */
debug("channel %d: close_write", c->self);
if (c->sock != -1) {
if (shutdown(c->sock, SHUT_WR) < 0)
debug("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)
log("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;
debug("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)
log("channel %d: chan_shutdown_read: "
"close() failed for fd%d: %.100s",
c->self, c->rfd, strerror(errno));
}
}