554 lines
14 KiB
C
554 lines
14 KiB
C
/*
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* Copyright (c) 1999 Markus Friedl. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "includes.h"
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RCSID("$OpenBSD: nchan.c,v 1.28 2001/05/31 10:30:16 markus Exp $");
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#include "ssh1.h"
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#include "ssh2.h"
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#include "buffer.h"
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#include "packet.h"
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#include "channels.h"
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#include "compat.h"
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#include "log.h"
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/*
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* SSH Protocol 1.5 aka New Channel Protocol
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* Thanks to Martina, Axel and everyone who left Erlangen, leaving me bored.
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* Written by Markus Friedl in October 1999
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*
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* Protocol versions 1.3 and 1.5 differ in the handshake protocol used for the
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* tear down of channels:
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*
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* 1.3: strict request-ack-protocol:
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* CLOSE ->
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* <- CLOSE_CONFIRM
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*
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* 1.5: uses variations of:
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* IEOF ->
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* <- OCLOSE
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* <- IEOF
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* OCLOSE ->
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* i.e. both sides have to close the channel
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*
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* 2.0: the EOF messages are optional
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*
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* See the debugging output from 'ssh -v' and 'sshd -d' of
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* ssh-1.2.27 as an example.
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*
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*/
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/* functions manipulating channel states */
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/*
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* EVENTS update channel input/output states execute ACTIONS
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*/
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/* events concerning the INPUT from socket for channel (istate) */
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chan_event_fn *chan_rcvd_oclose = NULL;
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chan_event_fn *chan_read_failed = NULL;
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chan_event_fn *chan_ibuf_empty = NULL;
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/* events concerning the OUTPUT from channel for socket (ostate) */
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chan_event_fn *chan_rcvd_ieof = NULL;
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chan_event_fn *chan_write_failed = NULL;
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chan_event_fn *chan_obuf_empty = NULL;
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/*
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* ACTIONS: should never update the channel states
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*/
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static void chan_send_ieof1(Channel *c);
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static void chan_send_oclose1(Channel *c);
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static void chan_send_close2(Channel *c);
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static void chan_send_eof2(Channel *c);
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/* helper */
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static void chan_shutdown_write(Channel *c);
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static void chan_shutdown_read(Channel *c);
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/*
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* SSH1 specific implementation of event functions
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*/
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static void
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chan_rcvd_oclose1(Channel *c)
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{
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debug("channel %d: rcvd oclose", c->self);
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switch (c->istate) {
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case CHAN_INPUT_WAIT_OCLOSE:
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debug("channel %d: input wait_oclose -> closed", c->self);
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c->istate = CHAN_INPUT_CLOSED;
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break;
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case CHAN_INPUT_OPEN:
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debug("channel %d: input open -> closed", c->self);
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chan_shutdown_read(c);
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chan_send_ieof1(c);
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c->istate = CHAN_INPUT_CLOSED;
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break;
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case CHAN_INPUT_WAIT_DRAIN:
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/* both local read_failed and remote write_failed */
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log("channel %d: input drain -> closed", c->self);
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chan_send_ieof1(c);
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c->istate = CHAN_INPUT_CLOSED;
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break;
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default:
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error("channel %d: protocol error: rcvd_oclose for istate %d",
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c->self, c->istate);
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return;
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}
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}
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static void
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chan_read_failed_12(Channel *c)
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{
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debug("channel %d: read failed", c->self);
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switch (c->istate) {
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case CHAN_INPUT_OPEN:
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debug("channel %d: input open -> drain", c->self);
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chan_shutdown_read(c);
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c->istate = CHAN_INPUT_WAIT_DRAIN;
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#if 0
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if (buffer_len(&c->input) == 0) {
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debug("channel %d: input: no drain shortcut", c->self);
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chan_ibuf_empty(c);
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}
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#endif
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break;
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default:
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error("channel %d: chan_read_failed for istate %d",
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c->self, c->istate);
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break;
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}
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}
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static void
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chan_ibuf_empty1(Channel *c)
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{
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debug("channel %d: ibuf empty", c->self);
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if (buffer_len(&c->input)) {
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error("channel %d: chan_ibuf_empty for non empty buffer",
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c->self);
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return;
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}
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switch (c->istate) {
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case CHAN_INPUT_WAIT_DRAIN:
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debug("channel %d: input drain -> wait_oclose", c->self);
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chan_send_ieof1(c);
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c->istate = CHAN_INPUT_WAIT_OCLOSE;
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break;
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default:
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error("channel %d: chan_ibuf_empty for istate %d",
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c->self, c->istate);
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break;
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}
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}
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static void
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chan_rcvd_ieof1(Channel *c)
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{
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debug("channel %d: rcvd ieof", c->self);
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if (c->type != SSH_CHANNEL_OPEN) {
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debug("channel %d: non-open", c->self);
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if (c->istate == CHAN_INPUT_OPEN) {
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debug("channel %d: non-open: input open -> wait_oclose",
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c->self);
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chan_shutdown_read(c);
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chan_send_ieof1(c);
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c->istate = CHAN_INPUT_WAIT_OCLOSE;
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} else {
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error("channel %d: non-open: istate %d != open",
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c->self, c->istate);
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}
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if (c->ostate == CHAN_OUTPUT_OPEN) {
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debug("channel %d: non-open: output open -> closed",
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c->self);
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chan_send_oclose1(c);
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c->ostate = CHAN_OUTPUT_CLOSED;
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} else {
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error("channel %d: non-open: ostate %d != open",
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c->self, c->ostate);
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}
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return;
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}
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switch (c->ostate) {
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case CHAN_OUTPUT_OPEN:
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debug("channel %d: output open -> drain", c->self);
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c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
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break;
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case CHAN_OUTPUT_WAIT_IEOF:
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debug("channel %d: output wait_ieof -> closed", c->self);
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c->ostate = CHAN_OUTPUT_CLOSED;
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break;
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default:
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error("channel %d: protocol error: rcvd_ieof for ostate %d",
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c->self, c->ostate);
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break;
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}
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}
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static void
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chan_write_failed1(Channel *c)
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{
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debug("channel %d: write failed", c->self);
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switch (c->ostate) {
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case CHAN_OUTPUT_OPEN:
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debug("channel %d: output open -> wait_ieof", c->self);
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chan_send_oclose1(c);
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c->ostate = CHAN_OUTPUT_WAIT_IEOF;
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break;
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case CHAN_OUTPUT_WAIT_DRAIN:
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debug("channel %d: output wait_drain -> closed", c->self);
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chan_send_oclose1(c);
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c->ostate = CHAN_OUTPUT_CLOSED;
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break;
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default:
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error("channel %d: chan_write_failed for ostate %d",
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c->self, c->ostate);
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break;
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}
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}
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static void
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chan_obuf_empty1(Channel *c)
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{
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debug("channel %d: obuf empty", c->self);
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if (buffer_len(&c->output)) {
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error("channel %d: chan_obuf_empty for non empty buffer",
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c->self);
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return;
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}
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switch (c->ostate) {
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case CHAN_OUTPUT_WAIT_DRAIN:
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debug("channel %d: output drain -> closed", c->self);
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chan_send_oclose1(c);
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c->ostate = CHAN_OUTPUT_CLOSED;
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break;
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default:
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error("channel %d: internal error: obuf_empty for ostate %d",
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c->self, c->ostate);
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break;
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}
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}
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static void
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chan_send_ieof1(Channel *c)
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{
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debug("channel %d: send ieof", c->self);
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switch (c->istate) {
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case CHAN_INPUT_OPEN:
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case CHAN_INPUT_WAIT_DRAIN:
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packet_start(SSH_MSG_CHANNEL_INPUT_EOF);
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packet_put_int(c->remote_id);
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packet_send();
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break;
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default:
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error("channel %d: cannot send ieof for istate %d",
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c->self, c->istate);
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break;
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}
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}
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static void
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chan_send_oclose1(Channel *c)
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{
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debug("channel %d: send oclose", c->self);
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switch (c->ostate) {
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case CHAN_OUTPUT_OPEN:
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case CHAN_OUTPUT_WAIT_DRAIN:
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chan_shutdown_write(c);
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buffer_consume(&c->output, buffer_len(&c->output));
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packet_start(SSH_MSG_CHANNEL_OUTPUT_CLOSE);
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packet_put_int(c->remote_id);
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packet_send();
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break;
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default:
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error("channel %d: cannot send oclose for ostate %d",
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c->self, c->ostate);
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break;
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}
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}
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/*
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* the same for SSH2
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*/
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static void
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chan_rcvd_oclose2(Channel *c)
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{
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debug("channel %d: rcvd close", c->self);
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if (c->flags & CHAN_CLOSE_RCVD)
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error("channel %d: protocol error: close rcvd twice", c->self);
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c->flags |= CHAN_CLOSE_RCVD;
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if (c->type == SSH_CHANNEL_LARVAL) {
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/* tear down larval channels immediately */
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c->ostate = CHAN_OUTPUT_CLOSED;
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c->istate = CHAN_INPUT_CLOSED;
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return;
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}
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switch (c->ostate) {
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case CHAN_OUTPUT_OPEN:
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/*
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* wait until a data from the channel is consumed if a CLOSE
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* is received
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*/
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debug("channel %d: output open -> drain", c->self);
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c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
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break;
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}
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switch (c->istate) {
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case CHAN_INPUT_OPEN:
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debug("channel %d: input open -> closed", c->self);
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chan_shutdown_read(c);
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break;
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case CHAN_INPUT_WAIT_DRAIN:
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debug("channel %d: input drain -> closed", c->self);
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chan_send_eof2(c);
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break;
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}
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c->istate = CHAN_INPUT_CLOSED;
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}
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static void
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chan_ibuf_empty2(Channel *c)
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{
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debug("channel %d: ibuf empty", c->self);
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if (buffer_len(&c->input)) {
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error("channel %d: chan_ibuf_empty for non empty buffer",
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c->self);
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return;
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}
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switch (c->istate) {
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case CHAN_INPUT_WAIT_DRAIN:
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debug("channel %d: input drain -> closed", c->self);
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if (!(c->flags & CHAN_CLOSE_SENT))
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chan_send_eof2(c);
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c->istate = CHAN_INPUT_CLOSED;
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break;
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default:
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error("channel %d: chan_ibuf_empty for istate %d",
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c->self, c->istate);
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break;
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}
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}
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static void
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chan_rcvd_ieof2(Channel *c)
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{
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debug("channel %d: rcvd eof", c->self);
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if (c->ostate == CHAN_OUTPUT_OPEN) {
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debug("channel %d: output open -> drain", c->self);
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c->ostate = CHAN_OUTPUT_WAIT_DRAIN;
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}
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}
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static void
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chan_write_failed2(Channel *c)
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{
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debug("channel %d: write failed", c->self);
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switch (c->ostate) {
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case CHAN_OUTPUT_OPEN:
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debug("channel %d: output open -> closed", c->self);
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chan_shutdown_write(c); /* ?? */
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c->ostate = CHAN_OUTPUT_CLOSED;
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break;
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case CHAN_OUTPUT_WAIT_DRAIN:
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debug("channel %d: output drain -> closed", c->self);
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chan_shutdown_write(c);
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c->ostate = CHAN_OUTPUT_CLOSED;
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break;
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default:
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error("channel %d: chan_write_failed for ostate %d",
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c->self, c->ostate);
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break;
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}
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}
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static void
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chan_obuf_empty2(Channel *c)
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{
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debug("channel %d: obuf empty", c->self);
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if (buffer_len(&c->output)) {
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error("channel %d: chan_obuf_empty for non empty buffer",
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c->self);
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return;
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}
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switch (c->ostate) {
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case CHAN_OUTPUT_WAIT_DRAIN:
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debug("channel %d: output drain -> closed", c->self);
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chan_shutdown_write(c);
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c->ostate = CHAN_OUTPUT_CLOSED;
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break;
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default:
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error("channel %d: chan_obuf_empty for ostate %d",
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c->self, c->ostate);
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break;
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}
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}
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static void
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chan_send_eof2(Channel *c)
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{
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debug("channel %d: send eof", c->self);
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switch (c->istate) {
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case CHAN_INPUT_WAIT_DRAIN:
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packet_start(SSH2_MSG_CHANNEL_EOF);
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packet_put_int(c->remote_id);
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packet_send();
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break;
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default:
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error("channel %d: cannot send eof for istate %d",
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c->self, c->istate);
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break;
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}
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}
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static void
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chan_send_close2(Channel *c)
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{
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debug("channel %d: send close", c->self);
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if (c->ostate != CHAN_OUTPUT_CLOSED ||
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c->istate != CHAN_INPUT_CLOSED) {
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error("channel %d: cannot send close for istate/ostate %d/%d",
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c->self, c->istate, c->ostate);
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} else if (c->flags & CHAN_CLOSE_SENT) {
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error("channel %d: already sent close", c->self);
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} else {
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packet_start(SSH2_MSG_CHANNEL_CLOSE);
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packet_put_int(c->remote_id);
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packet_send();
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c->flags |= CHAN_CLOSE_SENT;
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}
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}
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/* shared */
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void
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chan_mark_dead(Channel *c)
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{
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c->type = SSH_CHANNEL_ZOMBIE;
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}
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int
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chan_is_dead(Channel *c)
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{
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if (c->type == SSH_CHANNEL_ZOMBIE) {
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debug("channel %d: zombie", c->self);
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return 1;
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}
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if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
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return 0;
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if (!compat20) {
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debug("channel %d: is dead", c->self);
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return 1;
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}
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/*
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* we have to delay the close message if the efd (for stderr) is
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* still active
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*/
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if (((c->extended_usage != CHAN_EXTENDED_IGNORE) &&
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buffer_len(&c->extended) > 0)
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#if 0
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|| ((c->extended_usage == CHAN_EXTENDED_READ) &&
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c->efd != -1)
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#endif
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) {
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debug2("channel %d: active efd: %d len %d type %s",
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c->self, c->efd, buffer_len(&c->extended),
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c->extended_usage==CHAN_EXTENDED_READ ?
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"read": "write");
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} else {
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if (!(c->flags & CHAN_CLOSE_SENT)) {
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chan_send_close2(c);
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}
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if ((c->flags & CHAN_CLOSE_SENT) &&
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(c->flags & CHAN_CLOSE_RCVD)) {
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debug("channel %d: is dead", c->self);
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return 1;
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}
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}
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return 0;
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}
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void
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chan_init_iostates(Channel *c)
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{
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c->ostate = CHAN_OUTPUT_OPEN;
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c->istate = CHAN_INPUT_OPEN;
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c->flags = 0;
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}
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/* init */
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void
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chan_init(void)
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{
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if (compat20) {
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chan_rcvd_oclose = chan_rcvd_oclose2;
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chan_read_failed = chan_read_failed_12;
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chan_ibuf_empty = chan_ibuf_empty2;
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chan_rcvd_ieof = chan_rcvd_ieof2;
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chan_write_failed = chan_write_failed2;
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chan_obuf_empty = chan_obuf_empty2;
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} else {
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chan_rcvd_oclose = chan_rcvd_oclose1;
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chan_read_failed = chan_read_failed_12;
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chan_ibuf_empty = chan_ibuf_empty1;
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chan_rcvd_ieof = chan_rcvd_ieof1;
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chan_write_failed = chan_write_failed1;
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chan_obuf_empty = chan_obuf_empty1;
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}
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}
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/* helper */
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static void
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chan_shutdown_write(Channel *c)
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{
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|
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 (close(c->wfd) < 0)
|
|
log("channel %d: chan_shutdown_write: "
|
|
"close() failed for fd%d: %.100s",
|
|
c->self, c->wfd, strerror(errno));
|
|
c->wfd = -1;
|
|
}
|
|
}
|
|
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 will return EINVAL.
|
|
*/
|
|
if (shutdown(c->sock, SHUT_RD) < 0
|
|
&& (errno != ENOTCONN && errno != EINVAL))
|
|
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 (close(c->rfd) < 0)
|
|
log("channel %d: chan_shutdown_read: "
|
|
"close() failed for fd%d: %.100s",
|
|
c->self, c->rfd, strerror(errno));
|
|
c->rfd = -1;
|
|
}
|
|
}
|