1048 lines
28 KiB
C
Executable File
1048 lines
28 KiB
C
Executable File
/*
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* Dropbear SSH
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*
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* Copyright (c) 2002-2004 Matt Johnston
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* All rights reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE. */
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/* Handle the multiplexed channels, such as sessions, x11, agent connections */
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#include "includes.h"
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#include "session.h"
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#include "packet.h"
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#include "ssh.h"
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#include "buffer.h"
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#include "circbuffer.h"
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#include "dbutil.h"
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#include "channel.h"
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#include "ssh.h"
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#include "listener.h"
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#include "runopts.h"
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static void send_msg_channel_open_failure(unsigned int remotechan, int reason,
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const unsigned char *text, const unsigned char *lang);
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static void send_msg_channel_open_confirmation(struct Channel* channel,
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unsigned int recvwindow,
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unsigned int recvmaxpacket);
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static void writechannel(struct Channel* channel, int fd, circbuffer *cbuf);
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static void send_msg_channel_window_adjust(struct Channel *channel,
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unsigned int incr);
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static void send_msg_channel_data(struct Channel *channel, int isextended);
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static void send_msg_channel_eof(struct Channel *channel);
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static void send_msg_channel_close(struct Channel *channel);
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static void remove_channel(struct Channel *channel);
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static void delete_channel(struct Channel *channel);
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static void check_in_progress(struct Channel *channel);
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static unsigned int write_pending(struct Channel * channel);
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static void check_close(struct Channel *channel);
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static void close_chan_fd(struct Channel *channel, int fd, int how);
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#define FD_UNINIT (-2)
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#define FD_CLOSED (-1)
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#define ERRFD_IS_READ(channel) ((channel)->extrabuf == NULL)
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#define ERRFD_IS_WRITE(channel) (!ERRFD_IS_READ(channel))
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/* Initialise all the channels */
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void chaninitialise(const struct ChanType *chantypes[]) {
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/* may as well create space for a single channel */
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ses.channels = (struct Channel**)m_malloc(sizeof(struct Channel*));
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ses.chansize = 1;
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ses.channels[0] = NULL;
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ses.chancount = 0;
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ses.chantypes = chantypes;
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#ifdef USING_LISTENERS
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listeners_initialise();
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#endif
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}
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/* Clean up channels, freeing allocated memory */
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void chancleanup() {
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unsigned int i;
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TRACE(("enter chancleanup"))
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for (i = 0; i < ses.chansize; i++) {
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if (ses.channels[i] != NULL) {
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TRACE(("channel %d closing", i))
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remove_channel(ses.channels[i]);
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}
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}
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m_free(ses.channels);
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TRACE(("leave chancleanup"))
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}
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/* Create a new channel entry, send a reply confirm or failure */
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/* If remotechan, transwindow and transmaxpacket are not know (for a new
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* outgoing connection, with them to be filled on confirmation), they should
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* all be set to 0 */
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struct Channel* newchannel(unsigned int remotechan,
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const struct ChanType *type,
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unsigned int transwindow, unsigned int transmaxpacket) {
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struct Channel * newchan;
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unsigned int i, j;
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TRACE(("enter newchannel"))
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/* first see if we can use existing channels */
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for (i = 0; i < ses.chansize; i++) {
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if (ses.channels[i] == NULL) {
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break;
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}
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}
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/* otherwise extend the list */
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if (i == ses.chansize) {
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if (ses.chansize >= MAX_CHANNELS) {
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TRACE(("leave newchannel: max chans reached"))
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return NULL;
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}
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/* extend the channels */
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ses.channels = (struct Channel**)m_realloc(ses.channels,
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(ses.chansize+CHAN_EXTEND_SIZE)*sizeof(struct Channel*));
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ses.chansize += CHAN_EXTEND_SIZE;
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/* set the new channels to null */
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for (j = i; j < ses.chansize; j++) {
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ses.channels[j] = NULL;
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}
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}
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newchan = (struct Channel*)m_malloc(sizeof(struct Channel));
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newchan->type = type;
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newchan->index = i;
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newchan->sent_close = newchan->recv_close = 0;
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newchan->sent_eof = newchan->recv_eof = 0;
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newchan->remotechan = remotechan;
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newchan->transwindow = transwindow;
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newchan->transmaxpacket = transmaxpacket;
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newchan->typedata = NULL;
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newchan->writefd = FD_UNINIT;
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newchan->readfd = FD_UNINIT;
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newchan->errfd = FD_CLOSED; /* this isn't always set to start with */
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newchan->initconn = 0;
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newchan->await_open = 0;
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newchan->flushing = 0;
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newchan->writebuf = cbuf_new(opts.recv_window);
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newchan->extrabuf = NULL; /* The user code can set it up */
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newchan->recvwindow = opts.recv_window;
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newchan->recvdonelen = 0;
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newchan->recvmaxpacket = RECV_MAX_PAYLOAD_LEN;
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ses.channels[i] = newchan;
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ses.chancount++;
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TRACE(("leave newchannel"))
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return newchan;
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}
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/* Returns the channel structure corresponding to the channel in the current
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* data packet (ses.payload must be positioned appropriately).
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* A valid channel is always returns, it will fail fatally with an unknown
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* channel */
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static struct Channel* getchannel_msg(const char* kind) {
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unsigned int chan;
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chan = buf_getint(ses.payload);
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if (chan >= ses.chansize || ses.channels[chan] == NULL) {
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if (kind) {
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dropbear_exit("%s for unknown channel %d", kind, chan);
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} else {
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dropbear_exit("Unknown channel %d", chan);
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}
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}
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return ses.channels[chan];
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}
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struct Channel* getchannel() {
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return getchannel_msg(NULL);
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}
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/* Iterate through the channels, performing IO if available */
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void channelio(fd_set *readfds, fd_set *writefds) {
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struct Channel *channel;
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unsigned int i;
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/* foreach channel */
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for (i = 0; i < ses.chansize; i++) {
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channel = ses.channels[i];
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if (channel == NULL) {
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/* only process in-use channels */
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continue;
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}
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/* read data and send it over the wire */
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if (channel->readfd >= 0 && FD_ISSET(channel->readfd, readfds)) {
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TRACE(("send normal readfd"))
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send_msg_channel_data(channel, 0);
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}
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/* read stderr data and send it over the wire */
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if (ERRFD_IS_READ(channel) && channel->errfd >= 0
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&& FD_ISSET(channel->errfd, readfds)) {
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TRACE(("send normal errfd"))
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send_msg_channel_data(channel, 1);
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}
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/* write to program/pipe stdin */
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if (channel->writefd >= 0 && FD_ISSET(channel->writefd, writefds)) {
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if (channel->initconn) {
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/* XXX should this go somewhere cleaner? */
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check_in_progress(channel);
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continue; /* Important not to use the channel after
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check_in_progress(), as it may be NULL */
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}
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writechannel(channel, channel->writefd, channel->writebuf);
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}
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/* stderr for client mode */
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if (ERRFD_IS_WRITE(channel)
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&& channel->errfd >= 0 && FD_ISSET(channel->errfd, writefds)) {
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writechannel(channel, channel->errfd, channel->extrabuf);
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}
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/* handle any channel closing etc */
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check_close(channel);
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}
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/* Listeners such as TCP, X11, agent-auth */
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#ifdef USING_LISTENERS
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handle_listeners(readfds);
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#endif
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}
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/* Returns true if there is data remaining to be written to stdin or
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* stderr of a channel's endpoint. */
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static unsigned int write_pending(struct Channel * channel) {
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if (channel->writefd >= 0 && cbuf_getused(channel->writebuf) > 0) {
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return 1;
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} else if (channel->errfd >= 0 && channel->extrabuf &&
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cbuf_getused(channel->extrabuf) > 0) {
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return 1;
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}
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return 0;
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}
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/* EOF/close handling */
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static void check_close(struct Channel *channel) {
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int close_allowed = 0;
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TRACE(("check_close: writefd %d, readfd %d, errfd %d, sent_close %d, recv_close %d",
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channel->writefd, channel->readfd,
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channel->errfd, channel->sent_close, channel->recv_close))
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TRACE(("writebuf size %d extrabuf size %d",
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cbuf_getused(channel->writebuf),
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channel->extrabuf ? cbuf_getused(channel->extrabuf) : 0))
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if (!channel->flushing && channel->type->check_close
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&& channel->type->check_close(channel))
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{
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channel->flushing = 1;
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}
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/* if a type-specific check_close is defined we will only exit
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once that has been triggered. this is only used for a server "session"
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channel, to ensure that the shell has exited (and the exit status
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retrieved) before we close things up. */
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if (!channel->type->check_close
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|| channel->type->check_close(channel)) {
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close_allowed = 1;
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}
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if (channel->recv_close && !write_pending(channel) && close_allowed) {
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if (!channel->sent_close) {
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TRACE(("Sending MSG_CHANNEL_CLOSE in response to same."))
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send_msg_channel_close(channel);
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}
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remove_channel(channel);
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return;
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}
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if (channel->recv_eof && !write_pending(channel)) {
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close_chan_fd(channel, channel->writefd, SHUT_WR);
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}
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/* Special handling for flushing read data after an exit. We
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read regardless of whether the select FD was set,
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and if there isn't data available, the channel will get closed. */
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if (channel->flushing) {
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TRACE(("might send data, flushing"))
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if (channel->readfd >= 0 && channel->transwindow > 0) {
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TRACE(("send data readfd"))
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send_msg_channel_data(channel, 0);
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}
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if (ERRFD_IS_READ(channel) && channel->errfd >= 0
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&& channel->transwindow > 0) {
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TRACE(("send data errfd"))
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send_msg_channel_data(channel, 1);
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}
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}
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/* If we're not going to send any more data, send EOF */
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if (!channel->sent_eof
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&& channel->readfd == FD_CLOSED
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&& (ERRFD_IS_WRITE(channel) || channel->errfd == FD_CLOSED)) {
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send_msg_channel_eof(channel);
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}
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/* And if we can't receive any more data from them either, close up */
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if (channel->readfd == FD_CLOSED
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&& (ERRFD_IS_WRITE(channel) || channel->errfd == FD_CLOSED)
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&& !channel->sent_close
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&& close_allowed
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&& !write_pending(channel)) {
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TRACE(("sending close, readfd is closed"))
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send_msg_channel_close(channel);
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}
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}
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/* Check whether a deferred (EINPROGRESS) connect() was successful, and
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* if so, set up the channel properly. Otherwise, the channel is cleaned up, so
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* it is important that the channel reference isn't used after a call to this
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* function */
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static void check_in_progress(struct Channel *channel) {
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int val;
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socklen_t vallen = sizeof(val);
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TRACE(("enter check_in_progress"))
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if (getsockopt(channel->writefd, SOL_SOCKET, SO_ERROR, &val, &vallen)
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|| val != 0) {
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send_msg_channel_open_failure(channel->remotechan,
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SSH_OPEN_CONNECT_FAILED, "", "");
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close(channel->writefd);
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delete_channel(channel);
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TRACE(("leave check_in_progress: fail"))
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} else {
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send_msg_channel_open_confirmation(channel, channel->recvwindow,
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channel->recvmaxpacket);
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channel->readfd = channel->writefd;
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channel->initconn = 0;
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TRACE(("leave check_in_progress: success"))
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}
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}
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/* Send the close message and set the channel as closed */
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static void send_msg_channel_close(struct Channel *channel) {
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TRACE(("enter send_msg_channel_close"))
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if (channel->type->closehandler) {
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channel->type->closehandler(channel);
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}
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CHECKCLEARTOWRITE();
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buf_putbyte(ses.writepayload, SSH_MSG_CHANNEL_CLOSE);
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buf_putint(ses.writepayload, channel->remotechan);
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encrypt_packet();
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channel->sent_eof = 1;
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channel->sent_close = 1;
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close_chan_fd(channel, channel->readfd, SHUT_RD);
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close_chan_fd(channel, channel->errfd, SHUT_RDWR);
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close_chan_fd(channel, channel->writefd, SHUT_WR);
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TRACE(("leave send_msg_channel_close"))
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}
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/* call this when trans/eof channels are closed */
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static void send_msg_channel_eof(struct Channel *channel) {
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TRACE(("enter send_msg_channel_eof"))
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CHECKCLEARTOWRITE();
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buf_putbyte(ses.writepayload, SSH_MSG_CHANNEL_EOF);
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buf_putint(ses.writepayload, channel->remotechan);
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encrypt_packet();
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channel->sent_eof = 1;
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TRACE(("leave send_msg_channel_eof"))
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}
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/* Called to write data out to the local side of the channel.
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* Only called when we know we can write to a channel, writes as much as
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* possible */
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static void writechannel(struct Channel* channel, int fd, circbuffer *cbuf) {
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int len, maxlen;
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TRACE(("enter writechannel fd %d", fd))
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maxlen = cbuf_readlen(cbuf);
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/* Write the data out */
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len = write(fd, cbuf_readptr(cbuf, maxlen), maxlen);
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if (len <= 0) {
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TRACE(("errno %d len %d", errno, len))
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if (len < 0 && errno != EINTR) {
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close_chan_fd(channel, fd, SHUT_WR);
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}
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TRACE(("leave writechannel: len <= 0"))
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return;
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}
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TRACE(("writechannel wrote %d", len))
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cbuf_incrread(cbuf, len);
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channel->recvdonelen += len;
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/* Window adjust handling */
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if (channel->recvdonelen >= RECV_WINDOWEXTEND) {
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/* Set it back to max window */
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send_msg_channel_window_adjust(channel, channel->recvdonelen);
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channel->recvwindow += channel->recvdonelen;
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channel->recvdonelen = 0;
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}
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dropbear_assert(channel->recvwindow <= opts.recv_window);
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dropbear_assert(channel->recvwindow <= cbuf_getavail(channel->writebuf));
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dropbear_assert(channel->extrabuf == NULL ||
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channel->recvwindow <= cbuf_getavail(channel->extrabuf));
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TRACE(("leave writechannel"))
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}
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/* Set the file descriptors for the main select in session.c
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* This avoid channels which don't have any window available, are closed, etc*/
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void setchannelfds(fd_set *readfds, fd_set *writefds) {
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unsigned int i;
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struct Channel * channel;
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for (i = 0; i < ses.chansize; i++) {
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channel = ses.channels[i];
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if (channel == NULL) {
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continue;
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}
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/* Stuff to put over the wire */
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if (channel->transwindow > 0) {
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if (channel->readfd >= 0) {
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FD_SET(channel->readfd, readfds);
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}
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if (ERRFD_IS_READ(channel) && channel->errfd >= 0) {
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FD_SET(channel->errfd, readfds);
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}
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}
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/* Stuff from the wire */
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if ((channel->writefd >= 0 && cbuf_getused(channel->writebuf) > 0 )
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|| channel->initconn) {
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FD_SET(channel->writefd, writefds);
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}
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if (ERRFD_IS_WRITE(channel) && channel->errfd >= 0
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&& cbuf_getused(channel->extrabuf) > 0 ) {
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FD_SET(channel->errfd, writefds);
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}
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} /* foreach channel */
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#ifdef USING_LISTENERS
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set_listener_fds(readfds);
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#endif
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}
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|
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/* handle the channel EOF event, by closing the channel filedescriptor. The
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* channel isn't closed yet, it is left until the incoming (from the program
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* etc) FD is also EOF */
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void recv_msg_channel_eof() {
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struct Channel * channel;
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TRACE(("enter recv_msg_channel_eof"))
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channel = getchannel_msg("EOF");
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channel->recv_eof = 1;
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check_close(channel);
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TRACE(("leave recv_msg_channel_eof"))
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}
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/* Handle channel closure(), respond in kind and close the channels */
|
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void recv_msg_channel_close() {
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struct Channel * channel;
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TRACE(("enter recv_msg_channel_close"))
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channel = getchannel_msg("Close");
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channel->recv_eof = 1;
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channel->recv_close = 1;
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check_close(channel);
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TRACE(("leave recv_msg_channel_close"))
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}
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|
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/* Remove a channel entry, this is only executed after both sides have sent
|
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* channel close */
|
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static void remove_channel(struct Channel * channel) {
|
|
|
|
TRACE(("enter remove_channel"))
|
|
TRACE(("channel index is %d", channel->index))
|
|
|
|
cbuf_free(channel->writebuf);
|
|
channel->writebuf = NULL;
|
|
|
|
if (channel->extrabuf) {
|
|
cbuf_free(channel->extrabuf);
|
|
channel->extrabuf = NULL;
|
|
}
|
|
|
|
|
|
/* close the FDs in case they haven't been done
|
|
* yet (they might have been shutdown etc) */
|
|
TRACE(("CLOSE writefd %d", channel->writefd))
|
|
close(channel->writefd);
|
|
TRACE(("CLOSE readfd %d", channel->readfd))
|
|
close(channel->readfd);
|
|
TRACE(("CLOSE errfd %d", channel->errfd))
|
|
close(channel->errfd);
|
|
|
|
channel->typedata = NULL;
|
|
|
|
delete_channel(channel);
|
|
|
|
TRACE(("leave remove_channel"))
|
|
}
|
|
|
|
/* Remove a channel entry */
|
|
static void delete_channel(struct Channel *channel) {
|
|
|
|
ses.channels[channel->index] = NULL;
|
|
m_free(channel);
|
|
ses.chancount--;
|
|
|
|
}
|
|
|
|
|
|
/* Handle channel specific requests, passing off to corresponding handlers
|
|
* such as chansession or x11fwd */
|
|
void recv_msg_channel_request() {
|
|
|
|
struct Channel *channel;
|
|
|
|
TRACE(("enter recv_msg_channel_request"))
|
|
|
|
channel = getchannel();
|
|
|
|
if (channel->sent_close) {
|
|
TRACE(("leave recv_msg_channel_request: already closed channel"))
|
|
return;
|
|
}
|
|
|
|
if (channel->type->reqhandler) {
|
|
channel->type->reqhandler(channel);
|
|
} else {
|
|
send_msg_channel_failure(channel);
|
|
}
|
|
|
|
TRACE(("leave recv_msg_channel_request"))
|
|
|
|
}
|
|
|
|
/* Reads data from the server's program/shell/etc, and puts it in a
|
|
* channel_data packet to send.
|
|
* chan is the remote channel, isextended is 0 if it is normal data, 1
|
|
* if it is extended data. if it is extended, then the type is in
|
|
* exttype */
|
|
static void send_msg_channel_data(struct Channel *channel, int isextended) {
|
|
|
|
int len;
|
|
size_t maxlen, size_pos;
|
|
int fd;
|
|
|
|
CHECKCLEARTOWRITE();
|
|
|
|
TRACE(("enter send_msg_channel_data"))
|
|
dropbear_assert(!channel->sent_close);
|
|
|
|
if (isextended) {
|
|
fd = channel->errfd;
|
|
} else {
|
|
fd = channel->readfd;
|
|
}
|
|
TRACE(("enter send_msg_channel_data isextended %d fd %d", isextended, fd))
|
|
dropbear_assert(fd >= 0);
|
|
|
|
maxlen = MIN(channel->transwindow, channel->transmaxpacket);
|
|
/* -(1+4+4) is SSH_MSG_CHANNEL_DATA, channel number, string length, and
|
|
* exttype if is extended */
|
|
maxlen = MIN(maxlen,
|
|
ses.writepayload->size - 1 - 4 - 4 - (isextended ? 4 : 0));
|
|
TRACE(("maxlen %d", maxlen))
|
|
if (maxlen == 0) {
|
|
TRACE(("leave send_msg_channel_data: no window"))
|
|
return;
|
|
}
|
|
|
|
buf_putbyte(ses.writepayload,
|
|
isextended ? SSH_MSG_CHANNEL_EXTENDED_DATA : SSH_MSG_CHANNEL_DATA);
|
|
buf_putint(ses.writepayload, channel->remotechan);
|
|
if (isextended) {
|
|
buf_putint(ses.writepayload, SSH_EXTENDED_DATA_STDERR);
|
|
}
|
|
/* a dummy size first ...*/
|
|
size_pos = ses.writepayload->pos;
|
|
buf_putint(ses.writepayload, 0);
|
|
|
|
/* read the data */
|
|
len = read(fd, buf_getwriteptr(ses.writepayload, maxlen), maxlen);
|
|
if (len <= 0) {
|
|
if (len == 0 || errno != EINTR) {
|
|
/* This will also get hit in the case of EAGAIN. The only
|
|
time we expect to receive EAGAIN is when we're flushing a FD,
|
|
in which case it can be treated the same as EOF */
|
|
close_chan_fd(channel, fd, SHUT_RD);
|
|
}
|
|
ses.writepayload->len = ses.writepayload->pos = 0;
|
|
TRACE(("leave send_msg_channel_data: len %d read err %d or EOF for fd %d",
|
|
len, errno, fd))
|
|
return;
|
|
}
|
|
buf_incrwritepos(ses.writepayload, len);
|
|
/* ... real size here */
|
|
buf_setpos(ses.writepayload, size_pos);
|
|
buf_putint(ses.writepayload, len);
|
|
|
|
channel->transwindow -= len;
|
|
|
|
encrypt_packet();
|
|
|
|
/* If we receive less data than we requested when flushing, we've
|
|
reached the equivalent of EOF */
|
|
if (channel->flushing && len < (ssize_t)maxlen)
|
|
{
|
|
TRACE(("closing from channel, flushing out."))
|
|
close_chan_fd(channel, fd, SHUT_RD);
|
|
}
|
|
TRACE(("leave send_msg_channel_data"))
|
|
}
|
|
|
|
/* We receive channel data */
|
|
void recv_msg_channel_data() {
|
|
|
|
struct Channel *channel;
|
|
|
|
channel = getchannel();
|
|
|
|
common_recv_msg_channel_data(channel, channel->writefd, channel->writebuf);
|
|
}
|
|
|
|
/* Shared for data and stderr data - when we receive data, put it in a buffer
|
|
* for writing to the local file descriptor */
|
|
void common_recv_msg_channel_data(struct Channel *channel, int fd,
|
|
circbuffer * cbuf) {
|
|
|
|
unsigned int datalen;
|
|
unsigned int maxdata;
|
|
unsigned int buflen;
|
|
unsigned int len;
|
|
|
|
TRACE(("enter recv_msg_channel_data"))
|
|
|
|
if (channel->recv_eof) {
|
|
dropbear_exit("received data after eof");
|
|
}
|
|
|
|
if (fd < 0) {
|
|
/* If we have encountered failed write, the far side might still
|
|
* be sending data without having yet received our close notification.
|
|
* We just drop the data. */
|
|
return;
|
|
}
|
|
|
|
datalen = buf_getint(ses.payload);
|
|
TRACE(("length %d", datalen))
|
|
|
|
maxdata = cbuf_getavail(cbuf);
|
|
|
|
/* Whilst the spec says we "MAY ignore data past the end" this could
|
|
* lead to corrupted file transfers etc (chunks missed etc). It's better to
|
|
* just die horribly */
|
|
if (datalen > maxdata) {
|
|
dropbear_exit("Oversized packet");
|
|
}
|
|
|
|
/* We may have to run throught twice, if the buffer wraps around. Can't
|
|
* just "leave it for next time" like with writechannel, since this
|
|
* is payload data */
|
|
len = datalen;
|
|
while (len > 0) {
|
|
buflen = cbuf_writelen(cbuf);
|
|
buflen = MIN(buflen, len);
|
|
|
|
memcpy(cbuf_writeptr(cbuf, buflen),
|
|
buf_getptr(ses.payload, buflen), buflen);
|
|
cbuf_incrwrite(cbuf, buflen);
|
|
buf_incrpos(ses.payload, buflen);
|
|
len -= buflen;
|
|
}
|
|
|
|
dropbear_assert(channel->recvwindow >= datalen);
|
|
channel->recvwindow -= datalen;
|
|
dropbear_assert(channel->recvwindow <= opts.recv_window);
|
|
|
|
TRACE(("leave recv_msg_channel_data"))
|
|
}
|
|
|
|
/* Increment the outgoing data window for a channel - the remote end limits
|
|
* the amount of data which may be transmitted, this window is decremented
|
|
* as data is sent, and incremented upon receiving window-adjust messages */
|
|
void recv_msg_channel_window_adjust() {
|
|
|
|
struct Channel * channel;
|
|
unsigned int incr;
|
|
|
|
channel = getchannel();
|
|
|
|
incr = buf_getint(ses.payload);
|
|
TRACE(("received window increment %d", incr))
|
|
incr = MIN(incr, TRANS_MAX_WIN_INCR);
|
|
|
|
channel->transwindow += incr;
|
|
channel->transwindow = MIN(channel->transwindow, TRANS_MAX_WINDOW);
|
|
|
|
}
|
|
|
|
/* Increment the incoming data window for a channel, and let the remote
|
|
* end know */
|
|
static void send_msg_channel_window_adjust(struct Channel* channel,
|
|
unsigned int incr) {
|
|
|
|
TRACE(("sending window adjust %d", incr))
|
|
CHECKCLEARTOWRITE();
|
|
|
|
buf_putbyte(ses.writepayload, SSH_MSG_CHANNEL_WINDOW_ADJUST);
|
|
buf_putint(ses.writepayload, channel->remotechan);
|
|
buf_putint(ses.writepayload, incr);
|
|
|
|
encrypt_packet();
|
|
}
|
|
|
|
/* Handle a new channel request, performing any channel-type-specific setup */
|
|
void recv_msg_channel_open() {
|
|
|
|
unsigned char *type;
|
|
unsigned int typelen;
|
|
unsigned int remotechan, transwindow, transmaxpacket;
|
|
struct Channel *channel;
|
|
const struct ChanType **cp;
|
|
const struct ChanType *chantype;
|
|
unsigned int errtype = SSH_OPEN_UNKNOWN_CHANNEL_TYPE;
|
|
int ret;
|
|
|
|
|
|
TRACE(("enter recv_msg_channel_open"))
|
|
|
|
/* get the packet contents */
|
|
type = buf_getstring(ses.payload, &typelen);
|
|
|
|
remotechan = buf_getint(ses.payload);
|
|
transwindow = buf_getint(ses.payload);
|
|
transwindow = MIN(transwindow, TRANS_MAX_WINDOW);
|
|
transmaxpacket = buf_getint(ses.payload);
|
|
transmaxpacket = MIN(transmaxpacket, TRANS_MAX_PAYLOAD_LEN);
|
|
|
|
/* figure what type of packet it is */
|
|
if (typelen > MAX_NAME_LEN) {
|
|
goto failure;
|
|
}
|
|
|
|
/* Get the channel type. Client and server style invokation will set up a
|
|
* different list for ses.chantypes at startup. We just iterate through
|
|
* this list and find the matching name */
|
|
for (cp = &ses.chantypes[0], chantype = (*cp);
|
|
chantype != NULL;
|
|
cp++, chantype = (*cp)) {
|
|
if (strcmp(type, chantype->name) == 0) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (chantype == NULL) {
|
|
TRACE(("No matching type for '%s'", type))
|
|
goto failure;
|
|
}
|
|
|
|
TRACE(("matched type '%s'", type))
|
|
|
|
/* create the channel */
|
|
channel = newchannel(remotechan, chantype, transwindow, transmaxpacket);
|
|
|
|
if (channel == NULL) {
|
|
TRACE(("newchannel returned NULL"))
|
|
goto failure;
|
|
}
|
|
|
|
if (channel->type->inithandler) {
|
|
ret = channel->type->inithandler(channel);
|
|
if (ret == SSH_OPEN_IN_PROGRESS) {
|
|
/* We'll send the confirmation later */
|
|
goto cleanup;
|
|
}
|
|
if (ret > 0) {
|
|
errtype = ret;
|
|
delete_channel(channel);
|
|
TRACE(("inithandler returned failure %d", ret))
|
|
goto failure;
|
|
}
|
|
}
|
|
|
|
/* success */
|
|
send_msg_channel_open_confirmation(channel, channel->recvwindow,
|
|
channel->recvmaxpacket);
|
|
goto cleanup;
|
|
|
|
failure:
|
|
TRACE(("recv_msg_channel_open failure"))
|
|
send_msg_channel_open_failure(remotechan, errtype, "", "");
|
|
|
|
cleanup:
|
|
m_free(type);
|
|
|
|
TRACE(("leave recv_msg_channel_open"))
|
|
}
|
|
|
|
/* Send a failure message */
|
|
void send_msg_channel_failure(struct Channel *channel) {
|
|
|
|
TRACE(("enter send_msg_channel_failure"))
|
|
CHECKCLEARTOWRITE();
|
|
|
|
buf_putbyte(ses.writepayload, SSH_MSG_CHANNEL_FAILURE);
|
|
buf_putint(ses.writepayload, channel->remotechan);
|
|
|
|
encrypt_packet();
|
|
TRACE(("leave send_msg_channel_failure"))
|
|
}
|
|
|
|
/* Send a success message */
|
|
void send_msg_channel_success(struct Channel *channel) {
|
|
|
|
TRACE(("enter send_msg_channel_success"))
|
|
CHECKCLEARTOWRITE();
|
|
|
|
buf_putbyte(ses.writepayload, SSH_MSG_CHANNEL_SUCCESS);
|
|
buf_putint(ses.writepayload, channel->remotechan);
|
|
|
|
encrypt_packet();
|
|
TRACE(("leave send_msg_channel_success"))
|
|
}
|
|
|
|
/* Send a channel open failure message, with a corresponding reason
|
|
* code (usually resource shortage or unknown chan type) */
|
|
static void send_msg_channel_open_failure(unsigned int remotechan,
|
|
int reason, const unsigned char *text, const unsigned char *lang) {
|
|
|
|
TRACE(("enter send_msg_channel_open_failure"))
|
|
CHECKCLEARTOWRITE();
|
|
|
|
buf_putbyte(ses.writepayload, SSH_MSG_CHANNEL_OPEN_FAILURE);
|
|
buf_putint(ses.writepayload, remotechan);
|
|
buf_putint(ses.writepayload, reason);
|
|
buf_putstring(ses.writepayload, text, strlen((char*)text));
|
|
buf_putstring(ses.writepayload, lang, strlen((char*)lang));
|
|
|
|
encrypt_packet();
|
|
TRACE(("leave send_msg_channel_open_failure"))
|
|
}
|
|
|
|
/* Confirm a channel open, and let the remote end know what number we've
|
|
* allocated and the receive parameters */
|
|
static void send_msg_channel_open_confirmation(struct Channel* channel,
|
|
unsigned int recvwindow,
|
|
unsigned int recvmaxpacket) {
|
|
|
|
TRACE(("enter send_msg_channel_open_confirmation"))
|
|
CHECKCLEARTOWRITE();
|
|
|
|
buf_putbyte(ses.writepayload, SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
|
|
buf_putint(ses.writepayload, channel->remotechan);
|
|
buf_putint(ses.writepayload, channel->index);
|
|
buf_putint(ses.writepayload, recvwindow);
|
|
buf_putint(ses.writepayload, recvmaxpacket);
|
|
|
|
encrypt_packet();
|
|
TRACE(("leave send_msg_channel_open_confirmation"))
|
|
}
|
|
|
|
/* close a fd, how is SHUT_RD or SHUT_WR */
|
|
static void close_chan_fd(struct Channel *channel, int fd, int how) {
|
|
|
|
int closein = 0, closeout = 0;
|
|
|
|
if (channel->type->sepfds) {
|
|
TRACE(("SHUTDOWN(%d, %d)", fd, how))
|
|
shutdown(fd, how);
|
|
if (how == 0) {
|
|
closeout = 1;
|
|
} else {
|
|
closein = 1;
|
|
}
|
|
} else {
|
|
TRACE(("CLOSE some fd %d", fd))
|
|
close(fd);
|
|
closein = closeout = 1;
|
|
}
|
|
|
|
if (closeout && (fd == channel->readfd)) {
|
|
channel->readfd = FD_CLOSED;
|
|
}
|
|
if (closeout && ERRFD_IS_READ(channel) && (fd == channel->errfd)) {
|
|
channel->errfd = FD_CLOSED;
|
|
}
|
|
|
|
if (closein && fd == channel->writefd) {
|
|
channel->writefd = FD_CLOSED;
|
|
}
|
|
if (closein && ERRFD_IS_WRITE(channel) && (fd == channel->errfd)) {
|
|
channel->errfd = FD_CLOSED;
|
|
}
|
|
|
|
/* if we called shutdown on it and all references are gone, then we
|
|
* need to close() it to stop it lingering */
|
|
if (channel->type->sepfds && channel->readfd == FD_CLOSED
|
|
&& channel->writefd == FD_CLOSED && channel->errfd == FD_CLOSED) {
|
|
TRACE(("CLOSE (finally) of %d", fd))
|
|
close(fd);
|
|
}
|
|
}
|
|
|
|
|
|
#if defined(USING_LISTENERS) || defined(DROPBEAR_CLIENT)
|
|
/* Create a new channel, and start the open request. This is intended
|
|
* for X11, agent, tcp forwarding, and should be filled with channel-specific
|
|
* options, with the calling function calling encrypt_packet() after
|
|
* completion. It is mandatory for the caller to encrypt_packet() if
|
|
* DROPBEAR_SUCCESS is returned */
|
|
int send_msg_channel_open_init(int fd, const struct ChanType *type) {
|
|
|
|
struct Channel* chan;
|
|
|
|
TRACE(("enter send_msg_channel_open_init()"))
|
|
chan = newchannel(0, type, 0, 0);
|
|
if (!chan) {
|
|
TRACE(("leave send_msg_channel_open_init() - FAILED in newchannel()"))
|
|
return DROPBEAR_FAILURE;
|
|
}
|
|
|
|
/* set fd non-blocking */
|
|
setnonblocking(fd);
|
|
|
|
chan->writefd = chan->readfd = fd;
|
|
ses.maxfd = MAX(ses.maxfd, fd);
|
|
|
|
chan->await_open = 1;
|
|
|
|
/* now open the channel connection */
|
|
CHECKCLEARTOWRITE();
|
|
|
|
buf_putbyte(ses.writepayload, SSH_MSG_CHANNEL_OPEN);
|
|
buf_putstring(ses.writepayload, type->name, strlen(type->name));
|
|
buf_putint(ses.writepayload, chan->index);
|
|
buf_putint(ses.writepayload, opts.recv_window);
|
|
buf_putint(ses.writepayload, RECV_MAX_PAYLOAD_LEN);
|
|
|
|
TRACE(("leave send_msg_channel_open_init()"))
|
|
return DROPBEAR_SUCCESS;
|
|
}
|
|
|
|
/* Confirmation that our channel open request (for forwardings) was
|
|
* successful*/
|
|
void recv_msg_channel_open_confirmation() {
|
|
|
|
struct Channel * channel;
|
|
int ret;
|
|
|
|
TRACE(("enter recv_msg_channel_open_confirmation"))
|
|
|
|
channel = getchannel();
|
|
|
|
if (!channel->await_open) {
|
|
dropbear_exit("unexpected channel reply");
|
|
}
|
|
channel->await_open = 0;
|
|
|
|
channel->remotechan = buf_getint(ses.payload);
|
|
channel->transwindow = buf_getint(ses.payload);
|
|
channel->transmaxpacket = buf_getint(ses.payload);
|
|
|
|
TRACE(("new chan remote %d local %d",
|
|
channel->remotechan, channel->index))
|
|
|
|
/* Run the inithandler callback */
|
|
if (channel->type->inithandler) {
|
|
ret = channel->type->inithandler(channel);
|
|
if (ret > 0) {
|
|
remove_channel(channel);
|
|
TRACE(("inithandler returned failure %d", ret))
|
|
}
|
|
}
|
|
|
|
|
|
TRACE(("leave recv_msg_channel_open_confirmation"))
|
|
}
|
|
|
|
/* Notification that our channel open request failed */
|
|
void recv_msg_channel_open_failure() {
|
|
|
|
struct Channel * channel;
|
|
|
|
channel = getchannel();
|
|
|
|
if (!channel->await_open) {
|
|
dropbear_exit("unexpected channel reply");
|
|
}
|
|
channel->await_open = 0;
|
|
|
|
remove_channel(channel);
|
|
}
|
|
#endif /* USING_LISTENERS */
|