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b1ca8bb159
[channels.c clientloop.c serverloop.c session.c ssh.c] make channel_new() strdup the 'remote_name' (not the caller); ok theo
2766 lines
71 KiB
C
2766 lines
71 KiB
C
/*
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* Author: Tatu Ylonen <ylo@cs.hut.fi>
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* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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* All rights reserved
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* This file contains functions for generic socket connection forwarding.
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* There is also code for initiating connection forwarding for X11 connections,
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* arbitrary tcp/ip connections, and the authentication agent connection.
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*
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* As far as I am concerned, the code I have written for this software
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* can be used freely for any purpose. Any derived versions of this
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* software must be clearly marked as such, and if the derived work is
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* incompatible with the protocol description in the RFC file, it must be
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* called by a name other than "ssh" or "Secure Shell".
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*
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* SSH2 support added by Markus Friedl.
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* Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
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* Copyright (c) 1999 Dug Song. All rights reserved.
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* Copyright (c) 1999 Theo de Raadt. 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: channels.c,v 1.190 2003/05/11 20:30:24 markus Exp $");
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#include "ssh.h"
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#include "ssh1.h"
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#include "ssh2.h"
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#include "packet.h"
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#include "xmalloc.h"
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#include "log.h"
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#include "misc.h"
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#include "channels.h"
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#include "compat.h"
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#include "canohost.h"
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#include "key.h"
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#include "authfd.h"
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#include "pathnames.h"
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/* -- channel core */
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/*
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* Pointer to an array containing all allocated channels. The array is
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* dynamically extended as needed.
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*/
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static Channel **channels = NULL;
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/*
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* Size of the channel array. All slots of the array must always be
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* initialized (at least the type field); unused slots set to NULL
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*/
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static int channels_alloc = 0;
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/*
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* Maximum file descriptor value used in any of the channels. This is
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* updated in channel_new.
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*/
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static int channel_max_fd = 0;
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/* -- tcp forwarding */
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/*
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* Data structure for storing which hosts are permitted for forward requests.
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* The local sides of any remote forwards are stored in this array to prevent
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* a corrupt remote server from accessing arbitrary TCP/IP ports on our local
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* network (which might be behind a firewall).
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*/
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typedef struct {
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char *host_to_connect; /* Connect to 'host'. */
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u_short port_to_connect; /* Connect to 'port'. */
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u_short listen_port; /* Remote side should listen port number. */
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} ForwardPermission;
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/* List of all permitted host/port pairs to connect. */
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static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
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/* Number of permitted host/port pairs in the array. */
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static int num_permitted_opens = 0;
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/*
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* If this is true, all opens are permitted. This is the case on the server
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* on which we have to trust the client anyway, and the user could do
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* anything after logging in anyway.
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*/
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static int all_opens_permitted = 0;
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/* -- X11 forwarding */
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/* Maximum number of fake X11 displays to try. */
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#define MAX_DISPLAYS 1000
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/* Saved X11 authentication protocol name. */
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static char *x11_saved_proto = NULL;
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/* Saved X11 authentication data. This is the real data. */
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static char *x11_saved_data = NULL;
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static u_int x11_saved_data_len = 0;
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/*
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* Fake X11 authentication data. This is what the server will be sending us;
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* we should replace any occurrences of this by the real data.
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*/
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static char *x11_fake_data = NULL;
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static u_int x11_fake_data_len;
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/* -- agent forwarding */
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#define NUM_SOCKS 10
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/* AF_UNSPEC or AF_INET or AF_INET6 */
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static int IPv4or6 = AF_UNSPEC;
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/* helper */
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static void port_open_helper(Channel *c, char *rtype);
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/* -- channel core */
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Channel *
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channel_lookup(int id)
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{
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Channel *c;
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if (id < 0 || id >= channels_alloc) {
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logit("channel_lookup: %d: bad id", id);
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return NULL;
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}
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c = channels[id];
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if (c == NULL) {
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logit("channel_lookup: %d: bad id: channel free", id);
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return NULL;
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}
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return c;
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}
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/*
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* Register filedescriptors for a channel, used when allocating a channel or
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* when the channel consumer/producer is ready, e.g. shell exec'd
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*/
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static void
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channel_register_fds(Channel *c, int rfd, int wfd, int efd,
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int extusage, int nonblock)
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{
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/* Update the maximum file descriptor value. */
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channel_max_fd = MAX(channel_max_fd, rfd);
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channel_max_fd = MAX(channel_max_fd, wfd);
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channel_max_fd = MAX(channel_max_fd, efd);
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/* XXX set close-on-exec -markus */
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c->rfd = rfd;
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c->wfd = wfd;
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c->sock = (rfd == wfd) ? rfd : -1;
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c->efd = efd;
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c->extended_usage = extusage;
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/* XXX ugly hack: nonblock is only set by the server */
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if (nonblock && isatty(c->rfd)) {
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debug("channel %d: rfd %d isatty", c->self, c->rfd);
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c->isatty = 1;
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if (!isatty(c->wfd)) {
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error("channel %d: wfd %d is not a tty?",
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c->self, c->wfd);
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}
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} else {
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c->isatty = 0;
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}
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c->wfd_isatty = isatty(c->wfd);
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/* enable nonblocking mode */
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if (nonblock) {
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if (rfd != -1)
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set_nonblock(rfd);
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if (wfd != -1)
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set_nonblock(wfd);
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if (efd != -1)
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set_nonblock(efd);
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}
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}
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/*
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* Allocate a new channel object and set its type and socket. This will cause
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* remote_name to be freed.
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*/
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Channel *
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channel_new(char *ctype, int type, int rfd, int wfd, int efd,
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u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
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{
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int i, found;
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Channel *c;
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/* Do initial allocation if this is the first call. */
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if (channels_alloc == 0) {
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channels_alloc = 10;
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channels = xmalloc(channels_alloc * sizeof(Channel *));
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for (i = 0; i < channels_alloc; i++)
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channels[i] = NULL;
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fatal_add_cleanup((void (*) (void *)) channel_free_all, NULL);
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}
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/* Try to find a free slot where to put the new channel. */
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for (found = -1, i = 0; i < channels_alloc; i++)
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if (channels[i] == NULL) {
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/* Found a free slot. */
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found = i;
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break;
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}
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if (found == -1) {
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/* There are no free slots. Take last+1 slot and expand the array. */
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found = channels_alloc;
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channels_alloc += 10;
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if (channels_alloc > 10000)
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fatal("channel_new: internal error: channels_alloc %d "
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"too big.", channels_alloc);
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debug2("channel: expanding %d", channels_alloc);
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channels = xrealloc(channels, channels_alloc * sizeof(Channel *));
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for (i = found; i < channels_alloc; i++)
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channels[i] = NULL;
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}
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/* Initialize and return new channel. */
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c = channels[found] = xmalloc(sizeof(Channel));
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memset(c, 0, sizeof(Channel));
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buffer_init(&c->input);
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buffer_init(&c->output);
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buffer_init(&c->extended);
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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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channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
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c->self = found;
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c->type = type;
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c->ctype = ctype;
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c->local_window = window;
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c->local_window_max = window;
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c->local_consumed = 0;
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c->local_maxpacket = maxpack;
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c->remote_id = -1;
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c->remote_name = xstrdup(remote_name);
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c->remote_window = 0;
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c->remote_maxpacket = 0;
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c->force_drain = 0;
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c->single_connection = 0;
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c->detach_user = NULL;
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c->confirm = NULL;
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c->input_filter = NULL;
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debug("channel %d: new [%s]", found, remote_name);
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return c;
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}
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static int
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channel_find_maxfd(void)
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{
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int i, max = 0;
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Channel *c;
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for (i = 0; i < channels_alloc; i++) {
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c = channels[i];
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if (c != NULL) {
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max = MAX(max, c->rfd);
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max = MAX(max, c->wfd);
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max = MAX(max, c->efd);
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}
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}
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return max;
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}
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int
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channel_close_fd(int *fdp)
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{
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int ret = 0, fd = *fdp;
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if (fd != -1) {
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ret = close(fd);
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*fdp = -1;
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if (fd == channel_max_fd)
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channel_max_fd = channel_find_maxfd();
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}
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return ret;
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}
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/* Close all channel fd/socket. */
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static void
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channel_close_fds(Channel *c)
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{
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debug3("channel_close_fds: channel %d: r %d w %d e %d",
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c->self, c->rfd, c->wfd, c->efd);
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channel_close_fd(&c->sock);
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channel_close_fd(&c->rfd);
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channel_close_fd(&c->wfd);
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channel_close_fd(&c->efd);
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}
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/* Free the channel and close its fd/socket. */
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void
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channel_free(Channel *c)
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{
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char *s;
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int i, n;
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for (n = 0, i = 0; i < channels_alloc; i++)
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if (channels[i])
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n++;
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debug("channel_free: channel %d: %s, nchannels %d", c->self,
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c->remote_name ? c->remote_name : "???", n);
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s = channel_open_message();
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debug3("channel_free: status: %s", s);
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xfree(s);
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if (c->sock != -1)
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shutdown(c->sock, SHUT_RDWR);
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channel_close_fds(c);
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buffer_free(&c->input);
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buffer_free(&c->output);
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buffer_free(&c->extended);
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if (c->remote_name) {
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xfree(c->remote_name);
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c->remote_name = NULL;
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}
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channels[c->self] = NULL;
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xfree(c);
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}
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void
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channel_free_all(void)
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{
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int i;
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for (i = 0; i < channels_alloc; i++)
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if (channels[i] != NULL)
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channel_free(channels[i]);
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}
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/*
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* Closes the sockets/fds of all channels. This is used to close extra file
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* descriptors after a fork.
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*/
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void
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channel_close_all(void)
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{
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int i;
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for (i = 0; i < channels_alloc; i++)
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if (channels[i] != NULL)
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channel_close_fds(channels[i]);
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}
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/*
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* Stop listening to channels.
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*/
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void
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channel_stop_listening(void)
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{
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int i;
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Channel *c;
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for (i = 0; i < channels_alloc; i++) {
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c = channels[i];
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if (c != NULL) {
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switch (c->type) {
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case SSH_CHANNEL_AUTH_SOCKET:
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case SSH_CHANNEL_PORT_LISTENER:
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case SSH_CHANNEL_RPORT_LISTENER:
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case SSH_CHANNEL_X11_LISTENER:
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channel_close_fd(&c->sock);
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channel_free(c);
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break;
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}
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}
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}
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}
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/*
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* Returns true if no channel has too much buffered data, and false if one or
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* more channel is overfull.
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*/
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int
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channel_not_very_much_buffered_data(void)
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{
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u_int i;
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Channel *c;
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for (i = 0; i < channels_alloc; i++) {
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c = channels[i];
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if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
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#if 0
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if (!compat20 &&
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buffer_len(&c->input) > packet_get_maxsize()) {
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debug2("channel %d: big input buffer %d",
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c->self, buffer_len(&c->input));
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return 0;
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}
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#endif
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if (buffer_len(&c->output) > packet_get_maxsize()) {
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debug2("channel %d: big output buffer %d > %d",
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c->self, buffer_len(&c->output),
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packet_get_maxsize());
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return 0;
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}
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}
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}
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return 1;
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}
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/* Returns true if any channel is still open. */
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int
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channel_still_open(void)
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{
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int i;
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Channel *c;
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for (i = 0; i < channels_alloc; i++) {
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c = channels[i];
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if (c == NULL)
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continue;
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switch (c->type) {
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case SSH_CHANNEL_X11_LISTENER:
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case SSH_CHANNEL_PORT_LISTENER:
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case SSH_CHANNEL_RPORT_LISTENER:
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case SSH_CHANNEL_CLOSED:
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case SSH_CHANNEL_AUTH_SOCKET:
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case SSH_CHANNEL_DYNAMIC:
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case SSH_CHANNEL_CONNECTING:
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case SSH_CHANNEL_ZOMBIE:
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continue;
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case SSH_CHANNEL_LARVAL:
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if (!compat20)
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fatal("cannot happen: SSH_CHANNEL_LARVAL");
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continue;
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case SSH_CHANNEL_OPENING:
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case SSH_CHANNEL_OPEN:
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case SSH_CHANNEL_X11_OPEN:
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return 1;
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case SSH_CHANNEL_INPUT_DRAINING:
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case SSH_CHANNEL_OUTPUT_DRAINING:
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if (!compat13)
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fatal("cannot happen: OUT_DRAIN");
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return 1;
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default:
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fatal("channel_still_open: bad channel type %d", c->type);
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/* NOTREACHED */
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}
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}
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return 0;
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}
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/* Returns the id of an open channel suitable for keepaliving */
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int
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channel_find_open(void)
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{
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int i;
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Channel *c;
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for (i = 0; i < channels_alloc; i++) {
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c = channels[i];
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if (c == NULL)
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continue;
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switch (c->type) {
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case SSH_CHANNEL_CLOSED:
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case SSH_CHANNEL_DYNAMIC:
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case SSH_CHANNEL_X11_LISTENER:
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case SSH_CHANNEL_PORT_LISTENER:
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case SSH_CHANNEL_RPORT_LISTENER:
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case SSH_CHANNEL_OPENING:
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case SSH_CHANNEL_CONNECTING:
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case SSH_CHANNEL_ZOMBIE:
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continue;
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case SSH_CHANNEL_LARVAL:
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case SSH_CHANNEL_AUTH_SOCKET:
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case SSH_CHANNEL_OPEN:
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case SSH_CHANNEL_X11_OPEN:
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return i;
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case SSH_CHANNEL_INPUT_DRAINING:
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case SSH_CHANNEL_OUTPUT_DRAINING:
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if (!compat13)
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fatal("cannot happen: OUT_DRAIN");
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return i;
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default:
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fatal("channel_find_open: bad channel type %d", c->type);
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/* NOTREACHED */
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}
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}
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return -1;
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}
|
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|
|
|
|
/*
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* Returns a message describing the currently open forwarded connections,
|
|
* suitable for sending to the client. The message contains crlf pairs for
|
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* newlines.
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|
*/
|
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|
|
char *
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channel_open_message(void)
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|
{
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Buffer buffer;
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Channel *c;
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char buf[1024], *cp;
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int i;
|
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|
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buffer_init(&buffer);
|
|
snprintf(buf, sizeof buf, "The following connections are open:\r\n");
|
|
buffer_append(&buffer, buf, strlen(buf));
|
|
for (i = 0; i < channels_alloc; i++) {
|
|
c = channels[i];
|
|
if (c == NULL)
|
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continue;
|
|
switch (c->type) {
|
|
case SSH_CHANNEL_X11_LISTENER:
|
|
case SSH_CHANNEL_PORT_LISTENER:
|
|
case SSH_CHANNEL_RPORT_LISTENER:
|
|
case SSH_CHANNEL_CLOSED:
|
|
case SSH_CHANNEL_AUTH_SOCKET:
|
|
case SSH_CHANNEL_ZOMBIE:
|
|
continue;
|
|
case SSH_CHANNEL_LARVAL:
|
|
case SSH_CHANNEL_OPENING:
|
|
case SSH_CHANNEL_CONNECTING:
|
|
case SSH_CHANNEL_DYNAMIC:
|
|
case SSH_CHANNEL_OPEN:
|
|
case SSH_CHANNEL_X11_OPEN:
|
|
case SSH_CHANNEL_INPUT_DRAINING:
|
|
case SSH_CHANNEL_OUTPUT_DRAINING:
|
|
snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d)\r\n",
|
|
c->self, c->remote_name,
|
|
c->type, c->remote_id,
|
|
c->istate, buffer_len(&c->input),
|
|
c->ostate, buffer_len(&c->output),
|
|
c->rfd, c->wfd);
|
|
buffer_append(&buffer, buf, strlen(buf));
|
|
continue;
|
|
default:
|
|
fatal("channel_open_message: bad channel type %d", c->type);
|
|
/* NOTREACHED */
|
|
}
|
|
}
|
|
buffer_append(&buffer, "\0", 1);
|
|
cp = xstrdup(buffer_ptr(&buffer));
|
|
buffer_free(&buffer);
|
|
return cp;
|
|
}
|
|
|
|
void
|
|
channel_send_open(int id)
|
|
{
|
|
Channel *c = channel_lookup(id);
|
|
|
|
if (c == NULL) {
|
|
logit("channel_send_open: %d: bad id", id);
|
|
return;
|
|
}
|
|
debug2("channel %d: send open", id);
|
|
packet_start(SSH2_MSG_CHANNEL_OPEN);
|
|
packet_put_cstring(c->ctype);
|
|
packet_put_int(c->self);
|
|
packet_put_int(c->local_window);
|
|
packet_put_int(c->local_maxpacket);
|
|
packet_send();
|
|
}
|
|
|
|
void
|
|
channel_request_start(int id, char *service, int wantconfirm)
|
|
{
|
|
Channel *c = channel_lookup(id);
|
|
|
|
if (c == NULL) {
|
|
logit("channel_request_start: %d: unknown channel id", id);
|
|
return;
|
|
}
|
|
debug("channel %d: request %s", id, service) ;
|
|
packet_start(SSH2_MSG_CHANNEL_REQUEST);
|
|
packet_put_int(c->remote_id);
|
|
packet_put_cstring(service);
|
|
packet_put_char(wantconfirm);
|
|
}
|
|
void
|
|
channel_register_confirm(int id, channel_callback_fn *fn)
|
|
{
|
|
Channel *c = channel_lookup(id);
|
|
|
|
if (c == NULL) {
|
|
logit("channel_register_comfirm: %d: bad id", id);
|
|
return;
|
|
}
|
|
c->confirm = fn;
|
|
}
|
|
void
|
|
channel_register_cleanup(int id, channel_callback_fn *fn)
|
|
{
|
|
Channel *c = channel_lookup(id);
|
|
|
|
if (c == NULL) {
|
|
logit("channel_register_cleanup: %d: bad id", id);
|
|
return;
|
|
}
|
|
c->detach_user = fn;
|
|
}
|
|
void
|
|
channel_cancel_cleanup(int id)
|
|
{
|
|
Channel *c = channel_lookup(id);
|
|
|
|
if (c == NULL) {
|
|
logit("channel_cancel_cleanup: %d: bad id", id);
|
|
return;
|
|
}
|
|
c->detach_user = NULL;
|
|
}
|
|
void
|
|
channel_register_filter(int id, channel_filter_fn *fn)
|
|
{
|
|
Channel *c = channel_lookup(id);
|
|
|
|
if (c == NULL) {
|
|
logit("channel_register_filter: %d: bad id", id);
|
|
return;
|
|
}
|
|
c->input_filter = fn;
|
|
}
|
|
|
|
void
|
|
channel_set_fds(int id, int rfd, int wfd, int efd,
|
|
int extusage, int nonblock, u_int window_max)
|
|
{
|
|
Channel *c = channel_lookup(id);
|
|
|
|
if (c == NULL || c->type != SSH_CHANNEL_LARVAL)
|
|
fatal("channel_activate for non-larval channel %d.", id);
|
|
channel_register_fds(c, rfd, wfd, efd, extusage, nonblock);
|
|
c->type = SSH_CHANNEL_OPEN;
|
|
c->local_window = c->local_window_max = window_max;
|
|
packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
|
|
packet_put_int(c->remote_id);
|
|
packet_put_int(c->local_window);
|
|
packet_send();
|
|
}
|
|
|
|
/*
|
|
* 'channel_pre*' are called just before select() to add any bits relevant to
|
|
* channels in the select bitmasks.
|
|
*/
|
|
/*
|
|
* 'channel_post*': perform any appropriate operations for channels which
|
|
* have events pending.
|
|
*/
|
|
typedef void chan_fn(Channel *c, fd_set * readset, fd_set * writeset);
|
|
chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE];
|
|
chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE];
|
|
|
|
static void
|
|
channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
FD_SET(c->sock, readset);
|
|
}
|
|
|
|
static void
|
|
channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
debug3("channel %d: waiting for connection", c->self);
|
|
FD_SET(c->sock, writeset);
|
|
}
|
|
|
|
static void
|
|
channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
if (buffer_len(&c->input) < packet_get_maxsize())
|
|
FD_SET(c->sock, readset);
|
|
if (buffer_len(&c->output) > 0)
|
|
FD_SET(c->sock, writeset);
|
|
}
|
|
|
|
static void
|
|
channel_pre_open(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
u_int limit = compat20 ? c->remote_window : packet_get_maxsize();
|
|
|
|
if (c->istate == CHAN_INPUT_OPEN &&
|
|
limit > 0 &&
|
|
buffer_len(&c->input) < limit)
|
|
FD_SET(c->rfd, readset);
|
|
if (c->ostate == CHAN_OUTPUT_OPEN ||
|
|
c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
|
|
if (buffer_len(&c->output) > 0) {
|
|
FD_SET(c->wfd, writeset);
|
|
} else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
|
|
if (CHANNEL_EFD_OUTPUT_ACTIVE(c))
|
|
debug2("channel %d: obuf_empty delayed efd %d/(%d)",
|
|
c->self, c->efd, buffer_len(&c->extended));
|
|
else
|
|
chan_obuf_empty(c);
|
|
}
|
|
}
|
|
/** XXX check close conditions, too */
|
|
if (compat20 && c->efd != -1) {
|
|
if (c->extended_usage == CHAN_EXTENDED_WRITE &&
|
|
buffer_len(&c->extended) > 0)
|
|
FD_SET(c->efd, writeset);
|
|
else if (!(c->flags & CHAN_EOF_SENT) &&
|
|
c->extended_usage == CHAN_EXTENDED_READ &&
|
|
buffer_len(&c->extended) < c->remote_window)
|
|
FD_SET(c->efd, readset);
|
|
}
|
|
}
|
|
|
|
static void
|
|
channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
if (buffer_len(&c->input) == 0) {
|
|
packet_start(SSH_MSG_CHANNEL_CLOSE);
|
|
packet_put_int(c->remote_id);
|
|
packet_send();
|
|
c->type = SSH_CHANNEL_CLOSED;
|
|
debug("channel %d: closing after input drain.", c->self);
|
|
}
|
|
}
|
|
|
|
static void
|
|
channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
if (buffer_len(&c->output) == 0)
|
|
chan_mark_dead(c);
|
|
else
|
|
FD_SET(c->sock, writeset);
|
|
}
|
|
|
|
/*
|
|
* This is a special state for X11 authentication spoofing. An opened X11
|
|
* connection (when authentication spoofing is being done) remains in this
|
|
* state until the first packet has been completely read. The authentication
|
|
* data in that packet is then substituted by the real data if it matches the
|
|
* fake data, and the channel is put into normal mode.
|
|
* XXX All this happens at the client side.
|
|
* Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
|
|
*/
|
|
static int
|
|
x11_open_helper(Buffer *b)
|
|
{
|
|
u_char *ucp;
|
|
u_int proto_len, data_len;
|
|
|
|
/* Check if the fixed size part of the packet is in buffer. */
|
|
if (buffer_len(b) < 12)
|
|
return 0;
|
|
|
|
/* Parse the lengths of variable-length fields. */
|
|
ucp = buffer_ptr(b);
|
|
if (ucp[0] == 0x42) { /* Byte order MSB first. */
|
|
proto_len = 256 * ucp[6] + ucp[7];
|
|
data_len = 256 * ucp[8] + ucp[9];
|
|
} else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
|
|
proto_len = ucp[6] + 256 * ucp[7];
|
|
data_len = ucp[8] + 256 * ucp[9];
|
|
} else {
|
|
debug("Initial X11 packet contains bad byte order byte: 0x%x",
|
|
ucp[0]);
|
|
return -1;
|
|
}
|
|
|
|
/* Check if the whole packet is in buffer. */
|
|
if (buffer_len(b) <
|
|
12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
|
|
return 0;
|
|
|
|
/* Check if authentication protocol matches. */
|
|
if (proto_len != strlen(x11_saved_proto) ||
|
|
memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
|
|
debug("X11 connection uses different authentication protocol.");
|
|
return -1;
|
|
}
|
|
/* Check if authentication data matches our fake data. */
|
|
if (data_len != x11_fake_data_len ||
|
|
memcmp(ucp + 12 + ((proto_len + 3) & ~3),
|
|
x11_fake_data, x11_fake_data_len) != 0) {
|
|
debug("X11 auth data does not match fake data.");
|
|
return -1;
|
|
}
|
|
/* Check fake data length */
|
|
if (x11_fake_data_len != x11_saved_data_len) {
|
|
error("X11 fake_data_len %d != saved_data_len %d",
|
|
x11_fake_data_len, x11_saved_data_len);
|
|
return -1;
|
|
}
|
|
/*
|
|
* Received authentication protocol and data match
|
|
* our fake data. Substitute the fake data with real
|
|
* data.
|
|
*/
|
|
memcpy(ucp + 12 + ((proto_len + 3) & ~3),
|
|
x11_saved_data, x11_saved_data_len);
|
|
return 1;
|
|
}
|
|
|
|
static void
|
|
channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
int ret = x11_open_helper(&c->output);
|
|
|
|
if (ret == 1) {
|
|
/* Start normal processing for the channel. */
|
|
c->type = SSH_CHANNEL_OPEN;
|
|
channel_pre_open_13(c, readset, writeset);
|
|
} else if (ret == -1) {
|
|
/*
|
|
* We have received an X11 connection that has bad
|
|
* authentication information.
|
|
*/
|
|
logit("X11 connection rejected because of wrong authentication.");
|
|
buffer_clear(&c->input);
|
|
buffer_clear(&c->output);
|
|
channel_close_fd(&c->sock);
|
|
c->sock = -1;
|
|
c->type = SSH_CHANNEL_CLOSED;
|
|
packet_start(SSH_MSG_CHANNEL_CLOSE);
|
|
packet_put_int(c->remote_id);
|
|
packet_send();
|
|
}
|
|
}
|
|
|
|
static void
|
|
channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
int ret = x11_open_helper(&c->output);
|
|
|
|
/* c->force_drain = 1; */
|
|
|
|
if (ret == 1) {
|
|
c->type = SSH_CHANNEL_OPEN;
|
|
channel_pre_open(c, readset, writeset);
|
|
} else if (ret == -1) {
|
|
logit("X11 connection rejected because of wrong authentication.");
|
|
debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
|
|
chan_read_failed(c);
|
|
buffer_clear(&c->input);
|
|
chan_ibuf_empty(c);
|
|
buffer_clear(&c->output);
|
|
/* for proto v1, the peer will send an IEOF */
|
|
if (compat20)
|
|
chan_write_failed(c);
|
|
else
|
|
c->type = SSH_CHANNEL_OPEN;
|
|
debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
|
|
}
|
|
}
|
|
|
|
/* try to decode a socks4 header */
|
|
static int
|
|
channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
char *p, *host;
|
|
int len, have, i, found;
|
|
char username[256];
|
|
struct {
|
|
u_int8_t version;
|
|
u_int8_t command;
|
|
u_int16_t dest_port;
|
|
struct in_addr dest_addr;
|
|
} s4_req, s4_rsp;
|
|
|
|
debug2("channel %d: decode socks4", c->self);
|
|
|
|
have = buffer_len(&c->input);
|
|
len = sizeof(s4_req);
|
|
if (have < len)
|
|
return 0;
|
|
p = buffer_ptr(&c->input);
|
|
for (found = 0, i = len; i < have; i++) {
|
|
if (p[i] == '\0') {
|
|
found = 1;
|
|
break;
|
|
}
|
|
if (i > 1024) {
|
|
/* the peer is probably sending garbage */
|
|
debug("channel %d: decode socks4: too long",
|
|
c->self);
|
|
return -1;
|
|
}
|
|
}
|
|
if (!found)
|
|
return 0;
|
|
buffer_get(&c->input, (char *)&s4_req.version, 1);
|
|
buffer_get(&c->input, (char *)&s4_req.command, 1);
|
|
buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
|
|
buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
|
|
have = buffer_len(&c->input);
|
|
p = buffer_ptr(&c->input);
|
|
len = strlen(p);
|
|
debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
|
|
if (len > have)
|
|
fatal("channel %d: decode socks4: len %d > have %d",
|
|
c->self, len, have);
|
|
strlcpy(username, p, sizeof(username));
|
|
buffer_consume(&c->input, len);
|
|
buffer_consume(&c->input, 1); /* trailing '\0' */
|
|
|
|
host = inet_ntoa(s4_req.dest_addr);
|
|
strlcpy(c->path, host, sizeof(c->path));
|
|
c->host_port = ntohs(s4_req.dest_port);
|
|
|
|
debug("channel %d: dynamic request: socks4 host %s port %u command %u",
|
|
c->self, host, c->host_port, s4_req.command);
|
|
|
|
if (s4_req.command != 1) {
|
|
debug("channel %d: cannot handle: socks4 cn %d",
|
|
c->self, s4_req.command);
|
|
return -1;
|
|
}
|
|
s4_rsp.version = 0; /* vn: 0 for reply */
|
|
s4_rsp.command = 90; /* cd: req granted */
|
|
s4_rsp.dest_port = 0; /* ignored */
|
|
s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
|
|
buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
|
|
return 1;
|
|
}
|
|
|
|
/* dynamic port forwarding */
|
|
static void
|
|
channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
u_char *p;
|
|
int have, ret;
|
|
|
|
have = buffer_len(&c->input);
|
|
c->delayed = 0;
|
|
debug2("channel %d: pre_dynamic: have %d", c->self, have);
|
|
/* buffer_dump(&c->input); */
|
|
/* check if the fixed size part of the packet is in buffer. */
|
|
if (have < 4) {
|
|
/* need more */
|
|
FD_SET(c->sock, readset);
|
|
return;
|
|
}
|
|
/* try to guess the protocol */
|
|
p = buffer_ptr(&c->input);
|
|
switch (p[0]) {
|
|
case 0x04:
|
|
ret = channel_decode_socks4(c, readset, writeset);
|
|
break;
|
|
default:
|
|
ret = -1;
|
|
break;
|
|
}
|
|
if (ret < 0) {
|
|
chan_mark_dead(c);
|
|
} else if (ret == 0) {
|
|
debug2("channel %d: pre_dynamic: need more", c->self);
|
|
/* need more */
|
|
FD_SET(c->sock, readset);
|
|
} else {
|
|
/* switch to the next state */
|
|
c->type = SSH_CHANNEL_OPENING;
|
|
port_open_helper(c, "direct-tcpip");
|
|
}
|
|
}
|
|
|
|
/* This is our fake X11 server socket. */
|
|
static void
|
|
channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
Channel *nc;
|
|
struct sockaddr addr;
|
|
int newsock;
|
|
socklen_t addrlen;
|
|
char buf[16384], *remote_ipaddr;
|
|
int remote_port;
|
|
|
|
if (FD_ISSET(c->sock, readset)) {
|
|
debug("X11 connection requested.");
|
|
addrlen = sizeof(addr);
|
|
newsock = accept(c->sock, &addr, &addrlen);
|
|
if (c->single_connection) {
|
|
debug("single_connection: closing X11 listener.");
|
|
channel_close_fd(&c->sock);
|
|
chan_mark_dead(c);
|
|
}
|
|
if (newsock < 0) {
|
|
error("accept: %.100s", strerror(errno));
|
|
return;
|
|
}
|
|
set_nodelay(newsock);
|
|
remote_ipaddr = get_peer_ipaddr(newsock);
|
|
remote_port = get_peer_port(newsock);
|
|
snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
|
|
remote_ipaddr, remote_port);
|
|
|
|
nc = channel_new("accepted x11 socket",
|
|
SSH_CHANNEL_OPENING, newsock, newsock, -1,
|
|
c->local_window_max, c->local_maxpacket, 0, buf, 1);
|
|
if (compat20) {
|
|
packet_start(SSH2_MSG_CHANNEL_OPEN);
|
|
packet_put_cstring("x11");
|
|
packet_put_int(nc->self);
|
|
packet_put_int(nc->local_window_max);
|
|
packet_put_int(nc->local_maxpacket);
|
|
/* originator ipaddr and port */
|
|
packet_put_cstring(remote_ipaddr);
|
|
if (datafellows & SSH_BUG_X11FWD) {
|
|
debug("ssh2 x11 bug compat mode");
|
|
} else {
|
|
packet_put_int(remote_port);
|
|
}
|
|
packet_send();
|
|
} else {
|
|
packet_start(SSH_SMSG_X11_OPEN);
|
|
packet_put_int(nc->self);
|
|
if (packet_get_protocol_flags() &
|
|
SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
|
|
packet_put_cstring(buf);
|
|
packet_send();
|
|
}
|
|
xfree(remote_ipaddr);
|
|
}
|
|
}
|
|
|
|
static void
|
|
port_open_helper(Channel *c, char *rtype)
|
|
{
|
|
int direct;
|
|
char buf[1024];
|
|
char *remote_ipaddr = get_peer_ipaddr(c->sock);
|
|
u_short remote_port = get_peer_port(c->sock);
|
|
|
|
direct = (strcmp(rtype, "direct-tcpip") == 0);
|
|
|
|
snprintf(buf, sizeof buf,
|
|
"%s: listening port %d for %.100s port %d, "
|
|
"connect from %.200s port %d",
|
|
rtype, c->listening_port, c->path, c->host_port,
|
|
remote_ipaddr, remote_port);
|
|
|
|
xfree(c->remote_name);
|
|
c->remote_name = xstrdup(buf);
|
|
|
|
if (compat20) {
|
|
packet_start(SSH2_MSG_CHANNEL_OPEN);
|
|
packet_put_cstring(rtype);
|
|
packet_put_int(c->self);
|
|
packet_put_int(c->local_window_max);
|
|
packet_put_int(c->local_maxpacket);
|
|
if (direct) {
|
|
/* target host, port */
|
|
packet_put_cstring(c->path);
|
|
packet_put_int(c->host_port);
|
|
} else {
|
|
/* listen address, port */
|
|
packet_put_cstring(c->path);
|
|
packet_put_int(c->listening_port);
|
|
}
|
|
/* originator host and port */
|
|
packet_put_cstring(remote_ipaddr);
|
|
packet_put_int(remote_port);
|
|
packet_send();
|
|
} else {
|
|
packet_start(SSH_MSG_PORT_OPEN);
|
|
packet_put_int(c->self);
|
|
packet_put_cstring(c->path);
|
|
packet_put_int(c->host_port);
|
|
if (packet_get_protocol_flags() &
|
|
SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
|
|
packet_put_cstring(c->remote_name);
|
|
packet_send();
|
|
}
|
|
xfree(remote_ipaddr);
|
|
}
|
|
|
|
/*
|
|
* This socket is listening for connections to a forwarded TCP/IP port.
|
|
*/
|
|
static void
|
|
channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
Channel *nc;
|
|
struct sockaddr addr;
|
|
int newsock, nextstate;
|
|
socklen_t addrlen;
|
|
char *rtype;
|
|
|
|
if (FD_ISSET(c->sock, readset)) {
|
|
debug("Connection to port %d forwarding "
|
|
"to %.100s port %d requested.",
|
|
c->listening_port, c->path, c->host_port);
|
|
|
|
if (c->type == SSH_CHANNEL_RPORT_LISTENER) {
|
|
nextstate = SSH_CHANNEL_OPENING;
|
|
rtype = "forwarded-tcpip";
|
|
} else {
|
|
if (c->host_port == 0) {
|
|
nextstate = SSH_CHANNEL_DYNAMIC;
|
|
rtype = "dynamic-tcpip";
|
|
} else {
|
|
nextstate = SSH_CHANNEL_OPENING;
|
|
rtype = "direct-tcpip";
|
|
}
|
|
}
|
|
|
|
addrlen = sizeof(addr);
|
|
newsock = accept(c->sock, &addr, &addrlen);
|
|
if (newsock < 0) {
|
|
error("accept: %.100s", strerror(errno));
|
|
return;
|
|
}
|
|
set_nodelay(newsock);
|
|
nc = channel_new(rtype, nextstate, newsock, newsock, -1,
|
|
c->local_window_max, c->local_maxpacket, 0, rtype, 1);
|
|
nc->listening_port = c->listening_port;
|
|
nc->host_port = c->host_port;
|
|
strlcpy(nc->path, c->path, sizeof(nc->path));
|
|
|
|
if (nextstate == SSH_CHANNEL_DYNAMIC) {
|
|
/*
|
|
* do not call the channel_post handler until
|
|
* this flag has been reset by a pre-handler.
|
|
* otherwise the FD_ISSET calls might overflow
|
|
*/
|
|
nc->delayed = 1;
|
|
} else {
|
|
port_open_helper(nc, rtype);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This is the authentication agent socket listening for connections from
|
|
* clients.
|
|
*/
|
|
static void
|
|
channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
Channel *nc;
|
|
int newsock;
|
|
struct sockaddr addr;
|
|
socklen_t addrlen;
|
|
|
|
if (FD_ISSET(c->sock, readset)) {
|
|
addrlen = sizeof(addr);
|
|
newsock = accept(c->sock, &addr, &addrlen);
|
|
if (newsock < 0) {
|
|
error("accept from auth socket: %.100s", strerror(errno));
|
|
return;
|
|
}
|
|
nc = channel_new("accepted auth socket",
|
|
SSH_CHANNEL_OPENING, newsock, newsock, -1,
|
|
c->local_window_max, c->local_maxpacket,
|
|
0, "accepted auth socket", 1);
|
|
if (compat20) {
|
|
packet_start(SSH2_MSG_CHANNEL_OPEN);
|
|
packet_put_cstring("auth-agent@openssh.com");
|
|
packet_put_int(nc->self);
|
|
packet_put_int(c->local_window_max);
|
|
packet_put_int(c->local_maxpacket);
|
|
} else {
|
|
packet_start(SSH_SMSG_AGENT_OPEN);
|
|
packet_put_int(nc->self);
|
|
}
|
|
packet_send();
|
|
}
|
|
}
|
|
|
|
static void
|
|
channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
int err = 0;
|
|
socklen_t sz = sizeof(err);
|
|
|
|
if (FD_ISSET(c->sock, writeset)) {
|
|
if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) {
|
|
err = errno;
|
|
error("getsockopt SO_ERROR failed");
|
|
}
|
|
if (err == 0) {
|
|
debug("channel %d: connected", c->self);
|
|
c->type = SSH_CHANNEL_OPEN;
|
|
if (compat20) {
|
|
packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
|
|
packet_put_int(c->remote_id);
|
|
packet_put_int(c->self);
|
|
packet_put_int(c->local_window);
|
|
packet_put_int(c->local_maxpacket);
|
|
} else {
|
|
packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
|
|
packet_put_int(c->remote_id);
|
|
packet_put_int(c->self);
|
|
}
|
|
} else {
|
|
debug("channel %d: not connected: %s",
|
|
c->self, strerror(err));
|
|
if (compat20) {
|
|
packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
|
|
packet_put_int(c->remote_id);
|
|
packet_put_int(SSH2_OPEN_CONNECT_FAILED);
|
|
if (!(datafellows & SSH_BUG_OPENFAILURE)) {
|
|
packet_put_cstring(strerror(err));
|
|
packet_put_cstring("");
|
|
}
|
|
} else {
|
|
packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
|
|
packet_put_int(c->remote_id);
|
|
}
|
|
chan_mark_dead(c);
|
|
}
|
|
packet_send();
|
|
}
|
|
}
|
|
|
|
static int
|
|
channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
char buf[16*1024];
|
|
int len;
|
|
|
|
if (c->rfd != -1 &&
|
|
FD_ISSET(c->rfd, readset)) {
|
|
len = read(c->rfd, buf, sizeof(buf));
|
|
if (len < 0 && (errno == EINTR || errno == EAGAIN))
|
|
return 1;
|
|
if (len <= 0) {
|
|
debug("channel %d: read<=0 rfd %d len %d",
|
|
c->self, c->rfd, len);
|
|
if (c->type != SSH_CHANNEL_OPEN) {
|
|
debug("channel %d: not open", c->self);
|
|
chan_mark_dead(c);
|
|
return -1;
|
|
} else if (compat13) {
|
|
buffer_clear(&c->output);
|
|
c->type = SSH_CHANNEL_INPUT_DRAINING;
|
|
debug("channel %d: input draining.", c->self);
|
|
} else {
|
|
chan_read_failed(c);
|
|
}
|
|
return -1;
|
|
}
|
|
if (c->input_filter != NULL) {
|
|
if (c->input_filter(c, buf, len) == -1) {
|
|
debug("channel %d: filter stops", c->self);
|
|
chan_read_failed(c);
|
|
}
|
|
} else {
|
|
buffer_append(&c->input, buf, len);
|
|
}
|
|
}
|
|
return 1;
|
|
}
|
|
static int
|
|
channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
struct termios tio;
|
|
u_char *data;
|
|
u_int dlen;
|
|
int len;
|
|
|
|
/* Send buffered output data to the socket. */
|
|
if (c->wfd != -1 &&
|
|
FD_ISSET(c->wfd, writeset) &&
|
|
buffer_len(&c->output) > 0) {
|
|
data = buffer_ptr(&c->output);
|
|
dlen = buffer_len(&c->output);
|
|
#ifdef _AIX
|
|
/* XXX: Later AIX versions can't push as much data to tty */
|
|
if (compat20 && c->wfd_isatty && dlen > 8*1024)
|
|
dlen = 8*1024;
|
|
#endif
|
|
len = write(c->wfd, data, dlen);
|
|
if (len < 0 && (errno == EINTR || errno == EAGAIN))
|
|
return 1;
|
|
if (len <= 0) {
|
|
if (c->type != SSH_CHANNEL_OPEN) {
|
|
debug("channel %d: not open", c->self);
|
|
chan_mark_dead(c);
|
|
return -1;
|
|
} else if (compat13) {
|
|
buffer_clear(&c->output);
|
|
debug("channel %d: input draining.", c->self);
|
|
c->type = SSH_CHANNEL_INPUT_DRAINING;
|
|
} else {
|
|
chan_write_failed(c);
|
|
}
|
|
return -1;
|
|
}
|
|
if (compat20 && c->isatty && dlen >= 1 && data[0] != '\r') {
|
|
if (tcgetattr(c->wfd, &tio) == 0 &&
|
|
!(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
|
|
/*
|
|
* Simulate echo to reduce the impact of
|
|
* traffic analysis. We need to match the
|
|
* size of a SSH2_MSG_CHANNEL_DATA message
|
|
* (4 byte channel id + data)
|
|
*/
|
|
packet_send_ignore(4 + len);
|
|
packet_send();
|
|
}
|
|
}
|
|
buffer_consume(&c->output, len);
|
|
if (compat20 && len > 0) {
|
|
c->local_consumed += len;
|
|
}
|
|
}
|
|
return 1;
|
|
}
|
|
static int
|
|
channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
char buf[16*1024];
|
|
int len;
|
|
|
|
/** XXX handle drain efd, too */
|
|
if (c->efd != -1) {
|
|
if (c->extended_usage == CHAN_EXTENDED_WRITE &&
|
|
FD_ISSET(c->efd, writeset) &&
|
|
buffer_len(&c->extended) > 0) {
|
|
len = write(c->efd, buffer_ptr(&c->extended),
|
|
buffer_len(&c->extended));
|
|
debug2("channel %d: written %d to efd %d",
|
|
c->self, len, c->efd);
|
|
if (len < 0 && (errno == EINTR || errno == EAGAIN))
|
|
return 1;
|
|
if (len <= 0) {
|
|
debug2("channel %d: closing write-efd %d",
|
|
c->self, c->efd);
|
|
channel_close_fd(&c->efd);
|
|
} else {
|
|
buffer_consume(&c->extended, len);
|
|
c->local_consumed += len;
|
|
}
|
|
} else if (c->extended_usage == CHAN_EXTENDED_READ &&
|
|
FD_ISSET(c->efd, readset)) {
|
|
len = read(c->efd, buf, sizeof(buf));
|
|
debug2("channel %d: read %d from efd %d",
|
|
c->self, len, c->efd);
|
|
if (len < 0 && (errno == EINTR || errno == EAGAIN))
|
|
return 1;
|
|
if (len <= 0) {
|
|
debug2("channel %d: closing read-efd %d",
|
|
c->self, c->efd);
|
|
channel_close_fd(&c->efd);
|
|
} else {
|
|
buffer_append(&c->extended, buf, len);
|
|
}
|
|
}
|
|
}
|
|
return 1;
|
|
}
|
|
static int
|
|
channel_check_window(Channel *c)
|
|
{
|
|
if (c->type == SSH_CHANNEL_OPEN &&
|
|
!(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
|
|
c->local_window < c->local_window_max/2 &&
|
|
c->local_consumed > 0) {
|
|
packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST);
|
|
packet_put_int(c->remote_id);
|
|
packet_put_int(c->local_consumed);
|
|
packet_send();
|
|
debug2("channel %d: window %d sent adjust %d",
|
|
c->self, c->local_window,
|
|
c->local_consumed);
|
|
c->local_window += c->local_consumed;
|
|
c->local_consumed = 0;
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
static void
|
|
channel_post_open(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
if (c->delayed)
|
|
return;
|
|
channel_handle_rfd(c, readset, writeset);
|
|
channel_handle_wfd(c, readset, writeset);
|
|
if (!compat20)
|
|
return;
|
|
channel_handle_efd(c, readset, writeset);
|
|
channel_check_window(c);
|
|
}
|
|
|
|
static void
|
|
channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset)
|
|
{
|
|
int len;
|
|
|
|
/* Send buffered output data to the socket. */
|
|
if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) {
|
|
len = write(c->sock, buffer_ptr(&c->output),
|
|
buffer_len(&c->output));
|
|
if (len <= 0)
|
|
buffer_clear(&c->output);
|
|
else
|
|
buffer_consume(&c->output, len);
|
|
}
|
|
}
|
|
|
|
static void
|
|
channel_handler_init_20(void)
|
|
{
|
|
channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
|
|
channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
|
|
channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
|
|
channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener;
|
|
channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
|
|
channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
|
|
channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
|
|
channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
|
|
|
|
channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
|
|
channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
|
|
channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener;
|
|
channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
|
|
channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
|
|
channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
|
|
channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
|
|
}
|
|
|
|
static void
|
|
channel_handler_init_13(void)
|
|
{
|
|
channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13;
|
|
channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13;
|
|
channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
|
|
channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
|
|
channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
|
|
channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining;
|
|
channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining;
|
|
channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
|
|
channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
|
|
|
|
channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
|
|
channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
|
|
channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
|
|
channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
|
|
channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13;
|
|
channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
|
|
channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
|
|
}
|
|
|
|
static void
|
|
channel_handler_init_15(void)
|
|
{
|
|
channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open;
|
|
channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open;
|
|
channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener;
|
|
channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener;
|
|
channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener;
|
|
channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting;
|
|
channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic;
|
|
|
|
channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener;
|
|
channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener;
|
|
channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener;
|
|
channel_post[SSH_CHANNEL_OPEN] = &channel_post_open;
|
|
channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting;
|
|
channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open;
|
|
}
|
|
|
|
static void
|
|
channel_handler_init(void)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) {
|
|
channel_pre[i] = NULL;
|
|
channel_post[i] = NULL;
|
|
}
|
|
if (compat20)
|
|
channel_handler_init_20();
|
|
else if (compat13)
|
|
channel_handler_init_13();
|
|
else
|
|
channel_handler_init_15();
|
|
}
|
|
|
|
/* gc dead channels */
|
|
static void
|
|
channel_garbage_collect(Channel *c)
|
|
{
|
|
if (c == NULL)
|
|
return;
|
|
if (c->detach_user != NULL) {
|
|
if (!chan_is_dead(c, 0))
|
|
return;
|
|
debug("channel %d: gc: notify user", c->self);
|
|
c->detach_user(c->self, NULL);
|
|
/* if we still have a callback */
|
|
if (c->detach_user != NULL)
|
|
return;
|
|
debug("channel %d: gc: user detached", c->self);
|
|
}
|
|
if (!chan_is_dead(c, 1))
|
|
return;
|
|
debug("channel %d: garbage collecting", c->self);
|
|
channel_free(c);
|
|
}
|
|
|
|
static void
|
|
channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
|
|
{
|
|
static int did_init = 0;
|
|
int i;
|
|
Channel *c;
|
|
|
|
if (!did_init) {
|
|
channel_handler_init();
|
|
did_init = 1;
|
|
}
|
|
for (i = 0; i < channels_alloc; i++) {
|
|
c = channels[i];
|
|
if (c == NULL)
|
|
continue;
|
|
if (ftab[c->type] != NULL)
|
|
(*ftab[c->type])(c, readset, writeset);
|
|
channel_garbage_collect(c);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Allocate/update select bitmasks and add any bits relevant to channels in
|
|
* select bitmasks.
|
|
*/
|
|
void
|
|
channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
|
|
int *nallocp, int rekeying)
|
|
{
|
|
int n;
|
|
u_int sz;
|
|
|
|
n = MAX(*maxfdp, channel_max_fd);
|
|
|
|
sz = howmany(n+1, NFDBITS) * sizeof(fd_mask);
|
|
/* perhaps check sz < nalloc/2 and shrink? */
|
|
if (*readsetp == NULL || sz > *nallocp) {
|
|
*readsetp = xrealloc(*readsetp, sz);
|
|
*writesetp = xrealloc(*writesetp, sz);
|
|
*nallocp = sz;
|
|
}
|
|
*maxfdp = n;
|
|
memset(*readsetp, 0, sz);
|
|
memset(*writesetp, 0, sz);
|
|
|
|
if (!rekeying)
|
|
channel_handler(channel_pre, *readsetp, *writesetp);
|
|
}
|
|
|
|
/*
|
|
* After select, perform any appropriate operations for channels which have
|
|
* events pending.
|
|
*/
|
|
void
|
|
channel_after_select(fd_set * readset, fd_set * writeset)
|
|
{
|
|
channel_handler(channel_post, readset, writeset);
|
|
}
|
|
|
|
|
|
/* If there is data to send to the connection, enqueue some of it now. */
|
|
|
|
void
|
|
channel_output_poll(void)
|
|
{
|
|
Channel *c;
|
|
int i;
|
|
u_int len;
|
|
|
|
for (i = 0; i < channels_alloc; i++) {
|
|
c = channels[i];
|
|
if (c == NULL)
|
|
continue;
|
|
|
|
/*
|
|
* We are only interested in channels that can have buffered
|
|
* incoming data.
|
|
*/
|
|
if (compat13) {
|
|
if (c->type != SSH_CHANNEL_OPEN &&
|
|
c->type != SSH_CHANNEL_INPUT_DRAINING)
|
|
continue;
|
|
} else {
|
|
if (c->type != SSH_CHANNEL_OPEN)
|
|
continue;
|
|
}
|
|
if (compat20 &&
|
|
(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) {
|
|
/* XXX is this true? */
|
|
debug3("channel %d: will not send data after close", c->self);
|
|
continue;
|
|
}
|
|
|
|
/* Get the amount of buffered data for this channel. */
|
|
if ((c->istate == CHAN_INPUT_OPEN ||
|
|
c->istate == CHAN_INPUT_WAIT_DRAIN) &&
|
|
(len = buffer_len(&c->input)) > 0) {
|
|
/*
|
|
* Send some data for the other side over the secure
|
|
* connection.
|
|
*/
|
|
if (compat20) {
|
|
if (len > c->remote_window)
|
|
len = c->remote_window;
|
|
if (len > c->remote_maxpacket)
|
|
len = c->remote_maxpacket;
|
|
} else {
|
|
if (packet_is_interactive()) {
|
|
if (len > 1024)
|
|
len = 512;
|
|
} else {
|
|
/* Keep the packets at reasonable size. */
|
|
if (len > packet_get_maxsize()/2)
|
|
len = packet_get_maxsize()/2;
|
|
}
|
|
}
|
|
if (len > 0) {
|
|
packet_start(compat20 ?
|
|
SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA);
|
|
packet_put_int(c->remote_id);
|
|
packet_put_string(buffer_ptr(&c->input), len);
|
|
packet_send();
|
|
buffer_consume(&c->input, len);
|
|
c->remote_window -= len;
|
|
}
|
|
} else if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
|
|
if (compat13)
|
|
fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3");
|
|
/*
|
|
* input-buffer is empty and read-socket shutdown:
|
|
* tell peer, that we will not send more data: send IEOF.
|
|
* hack for extended data: delay EOF if EFD still in use.
|
|
*/
|
|
if (CHANNEL_EFD_INPUT_ACTIVE(c))
|
|
debug2("channel %d: ibuf_empty delayed efd %d/(%d)",
|
|
c->self, c->efd, buffer_len(&c->extended));
|
|
else
|
|
chan_ibuf_empty(c);
|
|
}
|
|
/* Send extended data, i.e. stderr */
|
|
if (compat20 &&
|
|
!(c->flags & CHAN_EOF_SENT) &&
|
|
c->remote_window > 0 &&
|
|
(len = buffer_len(&c->extended)) > 0 &&
|
|
c->extended_usage == CHAN_EXTENDED_READ) {
|
|
debug2("channel %d: rwin %u elen %u euse %d",
|
|
c->self, c->remote_window, buffer_len(&c->extended),
|
|
c->extended_usage);
|
|
if (len > c->remote_window)
|
|
len = c->remote_window;
|
|
if (len > c->remote_maxpacket)
|
|
len = c->remote_maxpacket;
|
|
packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA);
|
|
packet_put_int(c->remote_id);
|
|
packet_put_int(SSH2_EXTENDED_DATA_STDERR);
|
|
packet_put_string(buffer_ptr(&c->extended), len);
|
|
packet_send();
|
|
buffer_consume(&c->extended, len);
|
|
c->remote_window -= len;
|
|
debug2("channel %d: sent ext data %d", c->self, len);
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/* -- protocol input */
|
|
|
|
void
|
|
channel_input_data(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
int id;
|
|
char *data;
|
|
u_int data_len;
|
|
Channel *c;
|
|
|
|
/* Get the channel number and verify it. */
|
|
id = packet_get_int();
|
|
c = channel_lookup(id);
|
|
if (c == NULL)
|
|
packet_disconnect("Received data for nonexistent channel %d.", id);
|
|
|
|
/* Ignore any data for non-open channels (might happen on close) */
|
|
if (c->type != SSH_CHANNEL_OPEN &&
|
|
c->type != SSH_CHANNEL_X11_OPEN)
|
|
return;
|
|
|
|
/* same for protocol 1.5 if output end is no longer open */
|
|
if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN)
|
|
return;
|
|
|
|
/* Get the data. */
|
|
data = packet_get_string(&data_len);
|
|
|
|
if (compat20) {
|
|
if (data_len > c->local_maxpacket) {
|
|
logit("channel %d: rcvd big packet %d, maxpack %d",
|
|
c->self, data_len, c->local_maxpacket);
|
|
}
|
|
if (data_len > c->local_window) {
|
|
logit("channel %d: rcvd too much data %d, win %d",
|
|
c->self, data_len, c->local_window);
|
|
xfree(data);
|
|
return;
|
|
}
|
|
c->local_window -= data_len;
|
|
}
|
|
packet_check_eom();
|
|
buffer_append(&c->output, data, data_len);
|
|
xfree(data);
|
|
}
|
|
|
|
void
|
|
channel_input_extended_data(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
int id;
|
|
char *data;
|
|
u_int data_len, tcode;
|
|
Channel *c;
|
|
|
|
/* Get the channel number and verify it. */
|
|
id = packet_get_int();
|
|
c = channel_lookup(id);
|
|
|
|
if (c == NULL)
|
|
packet_disconnect("Received extended_data for bad channel %d.", id);
|
|
if (c->type != SSH_CHANNEL_OPEN) {
|
|
logit("channel %d: ext data for non open", id);
|
|
return;
|
|
}
|
|
if (c->flags & CHAN_EOF_RCVD) {
|
|
if (datafellows & SSH_BUG_EXTEOF)
|
|
debug("channel %d: accepting ext data after eof", id);
|
|
else
|
|
packet_disconnect("Received extended_data after EOF "
|
|
"on channel %d.", id);
|
|
}
|
|
tcode = packet_get_int();
|
|
if (c->efd == -1 ||
|
|
c->extended_usage != CHAN_EXTENDED_WRITE ||
|
|
tcode != SSH2_EXTENDED_DATA_STDERR) {
|
|
logit("channel %d: bad ext data", c->self);
|
|
return;
|
|
}
|
|
data = packet_get_string(&data_len);
|
|
packet_check_eom();
|
|
if (data_len > c->local_window) {
|
|
logit("channel %d: rcvd too much extended_data %d, win %d",
|
|
c->self, data_len, c->local_window);
|
|
xfree(data);
|
|
return;
|
|
}
|
|
debug2("channel %d: rcvd ext data %d", c->self, data_len);
|
|
c->local_window -= data_len;
|
|
buffer_append(&c->extended, data, data_len);
|
|
xfree(data);
|
|
}
|
|
|
|
void
|
|
channel_input_ieof(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
int id;
|
|
Channel *c;
|
|
|
|
id = packet_get_int();
|
|
packet_check_eom();
|
|
c = channel_lookup(id);
|
|
if (c == NULL)
|
|
packet_disconnect("Received ieof for nonexistent channel %d.", id);
|
|
chan_rcvd_ieof(c);
|
|
|
|
/* XXX force input close */
|
|
if (c->force_drain && c->istate == CHAN_INPUT_OPEN) {
|
|
debug("channel %d: FORCE input drain", c->self);
|
|
c->istate = CHAN_INPUT_WAIT_DRAIN;
|
|
if (buffer_len(&c->input) == 0)
|
|
chan_ibuf_empty(c);
|
|
}
|
|
|
|
}
|
|
|
|
void
|
|
channel_input_close(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
int id;
|
|
Channel *c;
|
|
|
|
id = packet_get_int();
|
|
packet_check_eom();
|
|
c = channel_lookup(id);
|
|
if (c == NULL)
|
|
packet_disconnect("Received close for nonexistent channel %d.", id);
|
|
|
|
/*
|
|
* Send a confirmation that we have closed the channel and no more
|
|
* data is coming for it.
|
|
*/
|
|
packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION);
|
|
packet_put_int(c->remote_id);
|
|
packet_send();
|
|
|
|
/*
|
|
* If the channel is in closed state, we have sent a close request,
|
|
* and the other side will eventually respond with a confirmation.
|
|
* Thus, we cannot free the channel here, because then there would be
|
|
* no-one to receive the confirmation. The channel gets freed when
|
|
* the confirmation arrives.
|
|
*/
|
|
if (c->type != SSH_CHANNEL_CLOSED) {
|
|
/*
|
|
* Not a closed channel - mark it as draining, which will
|
|
* cause it to be freed later.
|
|
*/
|
|
buffer_clear(&c->input);
|
|
c->type = SSH_CHANNEL_OUTPUT_DRAINING;
|
|
}
|
|
}
|
|
|
|
/* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
|
|
void
|
|
channel_input_oclose(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
int id = packet_get_int();
|
|
Channel *c = channel_lookup(id);
|
|
|
|
packet_check_eom();
|
|
if (c == NULL)
|
|
packet_disconnect("Received oclose for nonexistent channel %d.", id);
|
|
chan_rcvd_oclose(c);
|
|
}
|
|
|
|
void
|
|
channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
int id = packet_get_int();
|
|
Channel *c = channel_lookup(id);
|
|
|
|
packet_check_eom();
|
|
if (c == NULL)
|
|
packet_disconnect("Received close confirmation for "
|
|
"out-of-range channel %d.", id);
|
|
if (c->type != SSH_CHANNEL_CLOSED)
|
|
packet_disconnect("Received close confirmation for "
|
|
"non-closed channel %d (type %d).", id, c->type);
|
|
channel_free(c);
|
|
}
|
|
|
|
void
|
|
channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
int id, remote_id;
|
|
Channel *c;
|
|
|
|
id = packet_get_int();
|
|
c = channel_lookup(id);
|
|
|
|
if (c==NULL || c->type != SSH_CHANNEL_OPENING)
|
|
packet_disconnect("Received open confirmation for "
|
|
"non-opening channel %d.", id);
|
|
remote_id = packet_get_int();
|
|
/* Record the remote channel number and mark that the channel is now open. */
|
|
c->remote_id = remote_id;
|
|
c->type = SSH_CHANNEL_OPEN;
|
|
|
|
if (compat20) {
|
|
c->remote_window = packet_get_int();
|
|
c->remote_maxpacket = packet_get_int();
|
|
if (c->confirm) {
|
|
debug2("callback start");
|
|
c->confirm(c->self, NULL);
|
|
debug2("callback done");
|
|
}
|
|
debug("channel %d: open confirm rwindow %u rmax %u", c->self,
|
|
c->remote_window, c->remote_maxpacket);
|
|
}
|
|
packet_check_eom();
|
|
}
|
|
|
|
static char *
|
|
reason2txt(int reason)
|
|
{
|
|
switch (reason) {
|
|
case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED:
|
|
return "administratively prohibited";
|
|
case SSH2_OPEN_CONNECT_FAILED:
|
|
return "connect failed";
|
|
case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE:
|
|
return "unknown channel type";
|
|
case SSH2_OPEN_RESOURCE_SHORTAGE:
|
|
return "resource shortage";
|
|
}
|
|
return "unknown reason";
|
|
}
|
|
|
|
void
|
|
channel_input_open_failure(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
int id, reason;
|
|
char *msg = NULL, *lang = NULL;
|
|
Channel *c;
|
|
|
|
id = packet_get_int();
|
|
c = channel_lookup(id);
|
|
|
|
if (c==NULL || c->type != SSH_CHANNEL_OPENING)
|
|
packet_disconnect("Received open failure for "
|
|
"non-opening channel %d.", id);
|
|
if (compat20) {
|
|
reason = packet_get_int();
|
|
if (!(datafellows & SSH_BUG_OPENFAILURE)) {
|
|
msg = packet_get_string(NULL);
|
|
lang = packet_get_string(NULL);
|
|
}
|
|
logit("channel %d: open failed: %s%s%s", id,
|
|
reason2txt(reason), msg ? ": ": "", msg ? msg : "");
|
|
if (msg != NULL)
|
|
xfree(msg);
|
|
if (lang != NULL)
|
|
xfree(lang);
|
|
}
|
|
packet_check_eom();
|
|
/* Free the channel. This will also close the socket. */
|
|
channel_free(c);
|
|
}
|
|
|
|
void
|
|
channel_input_window_adjust(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
Channel *c;
|
|
int id;
|
|
u_int adjust;
|
|
|
|
if (!compat20)
|
|
return;
|
|
|
|
/* Get the channel number and verify it. */
|
|
id = packet_get_int();
|
|
c = channel_lookup(id);
|
|
|
|
if (c == NULL || c->type != SSH_CHANNEL_OPEN) {
|
|
logit("Received window adjust for "
|
|
"non-open channel %d.", id);
|
|
return;
|
|
}
|
|
adjust = packet_get_int();
|
|
packet_check_eom();
|
|
debug2("channel %d: rcvd adjust %u", id, adjust);
|
|
c->remote_window += adjust;
|
|
}
|
|
|
|
void
|
|
channel_input_port_open(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
Channel *c = NULL;
|
|
u_short host_port;
|
|
char *host, *originator_string;
|
|
int remote_id, sock = -1;
|
|
|
|
remote_id = packet_get_int();
|
|
host = packet_get_string(NULL);
|
|
host_port = packet_get_int();
|
|
|
|
if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
|
|
originator_string = packet_get_string(NULL);
|
|
} else {
|
|
originator_string = xstrdup("unknown (remote did not supply name)");
|
|
}
|
|
packet_check_eom();
|
|
sock = channel_connect_to(host, host_port);
|
|
if (sock != -1) {
|
|
c = channel_new("connected socket",
|
|
SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0,
|
|
originator_string, 1);
|
|
c->remote_id = remote_id;
|
|
}
|
|
xfree(originator_string);
|
|
if (c == NULL) {
|
|
packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
|
|
packet_put_int(remote_id);
|
|
packet_send();
|
|
}
|
|
xfree(host);
|
|
}
|
|
|
|
|
|
/* -- tcp forwarding */
|
|
|
|
void
|
|
channel_set_af(int af)
|
|
{
|
|
IPv4or6 = af;
|
|
}
|
|
|
|
static int
|
|
channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port,
|
|
const char *host_to_connect, u_short port_to_connect, int gateway_ports)
|
|
{
|
|
Channel *c;
|
|
int success, sock, on = 1;
|
|
struct addrinfo hints, *ai, *aitop;
|
|
const char *host;
|
|
char ntop[NI_MAXHOST], strport[NI_MAXSERV];
|
|
|
|
success = 0;
|
|
host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
|
|
listen_addr : host_to_connect;
|
|
|
|
if (host == NULL) {
|
|
error("No forward host name.");
|
|
return success;
|
|
}
|
|
if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) {
|
|
error("Forward host name too long.");
|
|
return success;
|
|
}
|
|
|
|
/*
|
|
* getaddrinfo returns a loopback address if the hostname is
|
|
* set to NULL and hints.ai_flags is not AI_PASSIVE
|
|
*/
|
|
memset(&hints, 0, sizeof(hints));
|
|
hints.ai_family = IPv4or6;
|
|
hints.ai_flags = gateway_ports ? AI_PASSIVE : 0;
|
|
hints.ai_socktype = SOCK_STREAM;
|
|
snprintf(strport, sizeof strport, "%d", listen_port);
|
|
if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
|
|
packet_disconnect("getaddrinfo: fatal error");
|
|
|
|
for (ai = aitop; ai; ai = ai->ai_next) {
|
|
if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
|
|
continue;
|
|
if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
|
|
strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
|
|
error("channel_setup_fwd_listener: getnameinfo failed");
|
|
continue;
|
|
}
|
|
/* Create a port to listen for the host. */
|
|
sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
|
|
if (sock < 0) {
|
|
/* this is no error since kernel may not support ipv6 */
|
|
verbose("socket: %.100s", strerror(errno));
|
|
continue;
|
|
}
|
|
/*
|
|
* Set socket options.
|
|
* Allow local port reuse in TIME_WAIT.
|
|
*/
|
|
if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on,
|
|
sizeof(on)) == -1)
|
|
error("setsockopt SO_REUSEADDR: %s", strerror(errno));
|
|
|
|
debug("Local forwarding listening on %s port %s.", ntop, strport);
|
|
|
|
/* Bind the socket to the address. */
|
|
if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
|
|
/* address can be in use ipv6 address is already bound */
|
|
if (!ai->ai_next)
|
|
error("bind: %.100s", strerror(errno));
|
|
else
|
|
verbose("bind: %.100s", strerror(errno));
|
|
|
|
close(sock);
|
|
continue;
|
|
}
|
|
/* Start listening for connections on the socket. */
|
|
if (listen(sock, 5) < 0) {
|
|
error("listen: %.100s", strerror(errno));
|
|
close(sock);
|
|
continue;
|
|
}
|
|
/* Allocate a channel number for the socket. */
|
|
c = channel_new("port listener", type, sock, sock, -1,
|
|
CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
|
|
0, "port listener", 1);
|
|
strlcpy(c->path, host, sizeof(c->path));
|
|
c->host_port = port_to_connect;
|
|
c->listening_port = listen_port;
|
|
success = 1;
|
|
}
|
|
if (success == 0)
|
|
error("channel_setup_fwd_listener: cannot listen to port: %d",
|
|
listen_port);
|
|
freeaddrinfo(aitop);
|
|
return success;
|
|
}
|
|
|
|
/* protocol local port fwd, used by ssh (and sshd in v1) */
|
|
int
|
|
channel_setup_local_fwd_listener(u_short listen_port,
|
|
const char *host_to_connect, u_short port_to_connect, int gateway_ports)
|
|
{
|
|
return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER,
|
|
NULL, listen_port, host_to_connect, port_to_connect, gateway_ports);
|
|
}
|
|
|
|
/* protocol v2 remote port fwd, used by sshd */
|
|
int
|
|
channel_setup_remote_fwd_listener(const char *listen_address,
|
|
u_short listen_port, int gateway_ports)
|
|
{
|
|
return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
|
|
listen_address, listen_port, NULL, 0, gateway_ports);
|
|
}
|
|
|
|
/*
|
|
* Initiate forwarding of connections to port "port" on remote host through
|
|
* the secure channel to host:port from local side.
|
|
*/
|
|
|
|
void
|
|
channel_request_remote_forwarding(u_short listen_port,
|
|
const char *host_to_connect, u_short port_to_connect)
|
|
{
|
|
int type, success = 0;
|
|
|
|
/* Record locally that connection to this host/port is permitted. */
|
|
if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
|
|
fatal("channel_request_remote_forwarding: too many forwards");
|
|
|
|
/* Send the forward request to the remote side. */
|
|
if (compat20) {
|
|
const char *address_to_bind = "0.0.0.0";
|
|
packet_start(SSH2_MSG_GLOBAL_REQUEST);
|
|
packet_put_cstring("tcpip-forward");
|
|
packet_put_char(1); /* boolean: want reply */
|
|
packet_put_cstring(address_to_bind);
|
|
packet_put_int(listen_port);
|
|
packet_send();
|
|
packet_write_wait();
|
|
/* Assume that server accepts the request */
|
|
success = 1;
|
|
} else {
|
|
packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
|
|
packet_put_int(listen_port);
|
|
packet_put_cstring(host_to_connect);
|
|
packet_put_int(port_to_connect);
|
|
packet_send();
|
|
packet_write_wait();
|
|
|
|
/* Wait for response from the remote side. */
|
|
type = packet_read();
|
|
switch (type) {
|
|
case SSH_SMSG_SUCCESS:
|
|
success = 1;
|
|
break;
|
|
case SSH_SMSG_FAILURE:
|
|
logit("Warning: Server denied remote port forwarding.");
|
|
break;
|
|
default:
|
|
/* Unknown packet */
|
|
packet_disconnect("Protocol error for port forward request:"
|
|
"received packet type %d.", type);
|
|
}
|
|
}
|
|
if (success) {
|
|
permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect);
|
|
permitted_opens[num_permitted_opens].port_to_connect = port_to_connect;
|
|
permitted_opens[num_permitted_opens].listen_port = listen_port;
|
|
num_permitted_opens++;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates
|
|
* listening for the port, and sends back a success reply (or disconnect
|
|
* message if there was an error). This never returns if there was an error.
|
|
*/
|
|
|
|
void
|
|
channel_input_port_forward_request(int is_root, int gateway_ports)
|
|
{
|
|
u_short port, host_port;
|
|
char *hostname;
|
|
|
|
/* Get arguments from the packet. */
|
|
port = packet_get_int();
|
|
hostname = packet_get_string(NULL);
|
|
host_port = packet_get_int();
|
|
|
|
#ifndef HAVE_CYGWIN
|
|
/*
|
|
* Check that an unprivileged user is not trying to forward a
|
|
* privileged port.
|
|
*/
|
|
if (port < IPPORT_RESERVED && !is_root)
|
|
packet_disconnect("Requested forwarding of port %d but user is not root.",
|
|
port);
|
|
#endif
|
|
/* Initiate forwarding */
|
|
channel_setup_local_fwd_listener(port, hostname, host_port, gateway_ports);
|
|
|
|
/* Free the argument string. */
|
|
xfree(hostname);
|
|
}
|
|
|
|
/*
|
|
* Permits opening to any host/port if permitted_opens[] is empty. This is
|
|
* usually called by the server, because the user could connect to any port
|
|
* anyway, and the server has no way to know but to trust the client anyway.
|
|
*/
|
|
void
|
|
channel_permit_all_opens(void)
|
|
{
|
|
if (num_permitted_opens == 0)
|
|
all_opens_permitted = 1;
|
|
}
|
|
|
|
void
|
|
channel_add_permitted_opens(char *host, int port)
|
|
{
|
|
if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
|
|
fatal("channel_request_remote_forwarding: too many forwards");
|
|
debug("allow port forwarding to host %s port %d", host, port);
|
|
|
|
permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host);
|
|
permitted_opens[num_permitted_opens].port_to_connect = port;
|
|
num_permitted_opens++;
|
|
|
|
all_opens_permitted = 0;
|
|
}
|
|
|
|
void
|
|
channel_clear_permitted_opens(void)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < num_permitted_opens; i++)
|
|
xfree(permitted_opens[i].host_to_connect);
|
|
num_permitted_opens = 0;
|
|
|
|
}
|
|
|
|
|
|
/* return socket to remote host, port */
|
|
static int
|
|
connect_to(const char *host, u_short port)
|
|
{
|
|
struct addrinfo hints, *ai, *aitop;
|
|
char ntop[NI_MAXHOST], strport[NI_MAXSERV];
|
|
int gaierr;
|
|
int sock = -1;
|
|
|
|
memset(&hints, 0, sizeof(hints));
|
|
hints.ai_family = IPv4or6;
|
|
hints.ai_socktype = SOCK_STREAM;
|
|
snprintf(strport, sizeof strport, "%d", port);
|
|
if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
|
|
error("connect_to %.100s: unknown host (%s)", host,
|
|
gai_strerror(gaierr));
|
|
return -1;
|
|
}
|
|
for (ai = aitop; ai; ai = ai->ai_next) {
|
|
if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
|
|
continue;
|
|
if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop),
|
|
strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
|
|
error("connect_to: getnameinfo failed");
|
|
continue;
|
|
}
|
|
sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
|
|
if (sock < 0) {
|
|
if (ai->ai_next == NULL)
|
|
error("socket: %.100s", strerror(errno));
|
|
else
|
|
verbose("socket: %.100s", strerror(errno));
|
|
continue;
|
|
}
|
|
if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0)
|
|
fatal("connect_to: F_SETFL: %s", strerror(errno));
|
|
if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 &&
|
|
errno != EINPROGRESS) {
|
|
error("connect_to %.100s port %s: %.100s", ntop, strport,
|
|
strerror(errno));
|
|
close(sock);
|
|
continue; /* fail -- try next */
|
|
}
|
|
break; /* success */
|
|
|
|
}
|
|
freeaddrinfo(aitop);
|
|
if (!ai) {
|
|
error("connect_to %.100s port %d: failed.", host, port);
|
|
return -1;
|
|
}
|
|
/* success */
|
|
set_nodelay(sock);
|
|
return sock;
|
|
}
|
|
|
|
int
|
|
channel_connect_by_listen_address(u_short listen_port)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < num_permitted_opens; i++)
|
|
if (permitted_opens[i].listen_port == listen_port)
|
|
return connect_to(
|
|
permitted_opens[i].host_to_connect,
|
|
permitted_opens[i].port_to_connect);
|
|
error("WARNING: Server requests forwarding for unknown listen_port %d",
|
|
listen_port);
|
|
return -1;
|
|
}
|
|
|
|
/* Check if connecting to that port is permitted and connect. */
|
|
int
|
|
channel_connect_to(const char *host, u_short port)
|
|
{
|
|
int i, permit;
|
|
|
|
permit = all_opens_permitted;
|
|
if (!permit) {
|
|
for (i = 0; i < num_permitted_opens; i++)
|
|
if (permitted_opens[i].port_to_connect == port &&
|
|
strcmp(permitted_opens[i].host_to_connect, host) == 0)
|
|
permit = 1;
|
|
|
|
}
|
|
if (!permit) {
|
|
logit("Received request to connect to host %.100s port %d, "
|
|
"but the request was denied.", host, port);
|
|
return -1;
|
|
}
|
|
return connect_to(host, port);
|
|
}
|
|
|
|
/* -- X11 forwarding */
|
|
|
|
/*
|
|
* Creates an internet domain socket for listening for X11 connections.
|
|
* Returns 0 and a suitable display number for the DISPLAY variable
|
|
* stored in display_numberp , or -1 if an error occurs.
|
|
*/
|
|
int
|
|
x11_create_display_inet(int x11_display_offset, int x11_use_localhost,
|
|
int single_connection, u_int *display_numberp)
|
|
{
|
|
Channel *nc = NULL;
|
|
int display_number, sock;
|
|
u_short port;
|
|
struct addrinfo hints, *ai, *aitop;
|
|
char strport[NI_MAXSERV];
|
|
int gaierr, n, num_socks = 0, socks[NUM_SOCKS];
|
|
|
|
for (display_number = x11_display_offset;
|
|
display_number < MAX_DISPLAYS;
|
|
display_number++) {
|
|
port = 6000 + display_number;
|
|
memset(&hints, 0, sizeof(hints));
|
|
hints.ai_family = IPv4or6;
|
|
hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE;
|
|
hints.ai_socktype = SOCK_STREAM;
|
|
snprintf(strport, sizeof strport, "%d", port);
|
|
if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) {
|
|
error("getaddrinfo: %.100s", gai_strerror(gaierr));
|
|
return -1;
|
|
}
|
|
for (ai = aitop; ai; ai = ai->ai_next) {
|
|
if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
|
|
continue;
|
|
sock = socket(ai->ai_family, ai->ai_socktype,
|
|
ai->ai_protocol);
|
|
if (sock < 0) {
|
|
if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) {
|
|
error("socket: %.100s", strerror(errno));
|
|
return -1;
|
|
} else {
|
|
debug("x11_create_display_inet: Socket family %d not supported",
|
|
ai->ai_family);
|
|
continue;
|
|
}
|
|
}
|
|
#ifdef IPV6_V6ONLY
|
|
if (ai->ai_family == AF_INET6) {
|
|
int on = 1;
|
|
if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0)
|
|
error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno));
|
|
}
|
|
#endif
|
|
if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
|
|
debug("bind port %d: %.100s", port, strerror(errno));
|
|
close(sock);
|
|
|
|
if (ai->ai_next)
|
|
continue;
|
|
|
|
for (n = 0; n < num_socks; n++) {
|
|
close(socks[n]);
|
|
}
|
|
num_socks = 0;
|
|
break;
|
|
}
|
|
socks[num_socks++] = sock;
|
|
#ifndef DONT_TRY_OTHER_AF
|
|
if (num_socks == NUM_SOCKS)
|
|
break;
|
|
#else
|
|
if (x11_use_localhost) {
|
|
if (num_socks == NUM_SOCKS)
|
|
break;
|
|
} else {
|
|
break;
|
|
}
|
|
#endif
|
|
}
|
|
freeaddrinfo(aitop);
|
|
if (num_socks > 0)
|
|
break;
|
|
}
|
|
if (display_number >= MAX_DISPLAYS) {
|
|
error("Failed to allocate internet-domain X11 display socket.");
|
|
return -1;
|
|
}
|
|
/* Start listening for connections on the socket. */
|
|
for (n = 0; n < num_socks; n++) {
|
|
sock = socks[n];
|
|
if (listen(sock, 5) < 0) {
|
|
error("listen: %.100s", strerror(errno));
|
|
close(sock);
|
|
return -1;
|
|
}
|
|
}
|
|
|
|
/* Allocate a channel for each socket. */
|
|
for (n = 0; n < num_socks; n++) {
|
|
sock = socks[n];
|
|
nc = channel_new("x11 listener",
|
|
SSH_CHANNEL_X11_LISTENER, sock, sock, -1,
|
|
CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT,
|
|
0, "X11 inet listener", 1);
|
|
nc->single_connection = single_connection;
|
|
}
|
|
|
|
/* Return the display number for the DISPLAY environment variable. */
|
|
*display_numberp = display_number;
|
|
return (0);
|
|
}
|
|
|
|
static int
|
|
connect_local_xsocket(u_int dnr)
|
|
{
|
|
int sock;
|
|
struct sockaddr_un addr;
|
|
|
|
sock = socket(AF_UNIX, SOCK_STREAM, 0);
|
|
if (sock < 0)
|
|
error("socket: %.100s", strerror(errno));
|
|
memset(&addr, 0, sizeof(addr));
|
|
addr.sun_family = AF_UNIX;
|
|
snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr);
|
|
if (connect(sock, (struct sockaddr *) & addr, sizeof(addr)) == 0)
|
|
return sock;
|
|
close(sock);
|
|
error("connect %.100s: %.100s", addr.sun_path, strerror(errno));
|
|
return -1;
|
|
}
|
|
|
|
int
|
|
x11_connect_display(void)
|
|
{
|
|
int display_number, sock = 0;
|
|
const char *display;
|
|
char buf[1024], *cp;
|
|
struct addrinfo hints, *ai, *aitop;
|
|
char strport[NI_MAXSERV];
|
|
int gaierr;
|
|
|
|
/* Try to open a socket for the local X server. */
|
|
display = getenv("DISPLAY");
|
|
if (!display) {
|
|
error("DISPLAY not set.");
|
|
return -1;
|
|
}
|
|
/*
|
|
* Now we decode the value of the DISPLAY variable and make a
|
|
* connection to the real X server.
|
|
*/
|
|
|
|
/*
|
|
* Check if it is a unix domain socket. Unix domain displays are in
|
|
* one of the following formats: unix:d[.s], :d[.s], ::d[.s]
|
|
*/
|
|
if (strncmp(display, "unix:", 5) == 0 ||
|
|
display[0] == ':') {
|
|
/* Connect to the unix domain socket. */
|
|
if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) {
|
|
error("Could not parse display number from DISPLAY: %.100s",
|
|
display);
|
|
return -1;
|
|
}
|
|
/* Create a socket. */
|
|
sock = connect_local_xsocket(display_number);
|
|
if (sock < 0)
|
|
return -1;
|
|
|
|
/* OK, we now have a connection to the display. */
|
|
return sock;
|
|
}
|
|
/*
|
|
* Connect to an inet socket. The DISPLAY value is supposedly
|
|
* hostname:d[.s], where hostname may also be numeric IP address.
|
|
*/
|
|
strlcpy(buf, display, sizeof(buf));
|
|
cp = strchr(buf, ':');
|
|
if (!cp) {
|
|
error("Could not find ':' in DISPLAY: %.100s", display);
|
|
return -1;
|
|
}
|
|
*cp = 0;
|
|
/* buf now contains the host name. But first we parse the display number. */
|
|
if (sscanf(cp + 1, "%d", &display_number) != 1) {
|
|
error("Could not parse display number from DISPLAY: %.100s",
|
|
display);
|
|
return -1;
|
|
}
|
|
|
|
/* Look up the host address */
|
|
memset(&hints, 0, sizeof(hints));
|
|
hints.ai_family = IPv4or6;
|
|
hints.ai_socktype = SOCK_STREAM;
|
|
snprintf(strport, sizeof strport, "%d", 6000 + display_number);
|
|
if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
|
|
error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr));
|
|
return -1;
|
|
}
|
|
for (ai = aitop; ai; ai = ai->ai_next) {
|
|
/* Create a socket. */
|
|
sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
|
|
if (sock < 0) {
|
|
debug("socket: %.100s", strerror(errno));
|
|
continue;
|
|
}
|
|
/* Connect it to the display. */
|
|
if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
|
|
debug("connect %.100s port %d: %.100s", buf,
|
|
6000 + display_number, strerror(errno));
|
|
close(sock);
|
|
continue;
|
|
}
|
|
/* Success */
|
|
break;
|
|
}
|
|
freeaddrinfo(aitop);
|
|
if (!ai) {
|
|
error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
|
|
strerror(errno));
|
|
return -1;
|
|
}
|
|
set_nodelay(sock);
|
|
return sock;
|
|
}
|
|
|
|
/*
|
|
* This is called when SSH_SMSG_X11_OPEN is received. The packet contains
|
|
* the remote channel number. We should do whatever we want, and respond
|
|
* with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE.
|
|
*/
|
|
|
|
void
|
|
x11_input_open(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
Channel *c = NULL;
|
|
int remote_id, sock = 0;
|
|
char *remote_host;
|
|
|
|
debug("Received X11 open request.");
|
|
|
|
remote_id = packet_get_int();
|
|
|
|
if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) {
|
|
remote_host = packet_get_string(NULL);
|
|
} else {
|
|
remote_host = xstrdup("unknown (remote did not supply name)");
|
|
}
|
|
packet_check_eom();
|
|
|
|
/* Obtain a connection to the real X display. */
|
|
sock = x11_connect_display();
|
|
if (sock != -1) {
|
|
/* Allocate a channel for this connection. */
|
|
c = channel_new("connected x11 socket",
|
|
SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0,
|
|
remote_host, 1);
|
|
c->remote_id = remote_id;
|
|
c->force_drain = 1;
|
|
}
|
|
xfree(remote_host);
|
|
if (c == NULL) {
|
|
/* Send refusal to the remote host. */
|
|
packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
|
|
packet_put_int(remote_id);
|
|
} else {
|
|
/* Send a confirmation to the remote host. */
|
|
packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
|
|
packet_put_int(remote_id);
|
|
packet_put_int(c->self);
|
|
}
|
|
packet_send();
|
|
}
|
|
|
|
/* dummy protocol handler that denies SSH-1 requests (agent/x11) */
|
|
void
|
|
deny_input_open(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
int rchan = packet_get_int();
|
|
|
|
switch (type) {
|
|
case SSH_SMSG_AGENT_OPEN:
|
|
error("Warning: ssh server tried agent forwarding.");
|
|
break;
|
|
case SSH_SMSG_X11_OPEN:
|
|
error("Warning: ssh server tried X11 forwarding.");
|
|
break;
|
|
default:
|
|
error("deny_input_open: type %d", type);
|
|
break;
|
|
}
|
|
error("Warning: this is probably a break in attempt by a malicious server.");
|
|
packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
|
|
packet_put_int(rchan);
|
|
packet_send();
|
|
}
|
|
|
|
/*
|
|
* Requests forwarding of X11 connections, generates fake authentication
|
|
* data, and enables authentication spoofing.
|
|
* This should be called in the client only.
|
|
*/
|
|
void
|
|
x11_request_forwarding_with_spoofing(int client_session_id,
|
|
const char *proto, const char *data)
|
|
{
|
|
u_int data_len = (u_int) strlen(data) / 2;
|
|
u_int i, value, len;
|
|
char *new_data;
|
|
int screen_number;
|
|
const char *cp;
|
|
u_int32_t rand = 0;
|
|
|
|
cp = getenv("DISPLAY");
|
|
if (cp)
|
|
cp = strchr(cp, ':');
|
|
if (cp)
|
|
cp = strchr(cp, '.');
|
|
if (cp)
|
|
screen_number = atoi(cp + 1);
|
|
else
|
|
screen_number = 0;
|
|
|
|
/* Save protocol name. */
|
|
x11_saved_proto = xstrdup(proto);
|
|
|
|
/*
|
|
* Extract real authentication data and generate fake data of the
|
|
* same length.
|
|
*/
|
|
x11_saved_data = xmalloc(data_len);
|
|
x11_fake_data = xmalloc(data_len);
|
|
for (i = 0; i < data_len; i++) {
|
|
if (sscanf(data + 2 * i, "%2x", &value) != 1)
|
|
fatal("x11_request_forwarding: bad authentication data: %.100s", data);
|
|
if (i % 4 == 0)
|
|
rand = arc4random();
|
|
x11_saved_data[i] = value;
|
|
x11_fake_data[i] = rand & 0xff;
|
|
rand >>= 8;
|
|
}
|
|
x11_saved_data_len = data_len;
|
|
x11_fake_data_len = data_len;
|
|
|
|
/* Convert the fake data into hex. */
|
|
len = 2 * data_len + 1;
|
|
new_data = xmalloc(len);
|
|
for (i = 0; i < data_len; i++)
|
|
snprintf(new_data + 2 * i, len - 2 * i,
|
|
"%02x", (u_char) x11_fake_data[i]);
|
|
|
|
/* Send the request packet. */
|
|
if (compat20) {
|
|
channel_request_start(client_session_id, "x11-req", 0);
|
|
packet_put_char(0); /* XXX bool single connection */
|
|
} else {
|
|
packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
|
|
}
|
|
packet_put_cstring(proto);
|
|
packet_put_cstring(new_data);
|
|
packet_put_int(screen_number);
|
|
packet_send();
|
|
packet_write_wait();
|
|
xfree(new_data);
|
|
}
|
|
|
|
|
|
/* -- agent forwarding */
|
|
|
|
/* Sends a message to the server to request authentication fd forwarding. */
|
|
|
|
void
|
|
auth_request_forwarding(void)
|
|
{
|
|
packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
|
|
packet_send();
|
|
packet_write_wait();
|
|
}
|
|
|
|
/* This is called to process an SSH_SMSG_AGENT_OPEN message. */
|
|
|
|
void
|
|
auth_input_open_request(int type, u_int32_t seq, void *ctxt)
|
|
{
|
|
Channel *c = NULL;
|
|
int remote_id, sock;
|
|
|
|
/* Read the remote channel number from the message. */
|
|
remote_id = packet_get_int();
|
|
packet_check_eom();
|
|
|
|
/*
|
|
* Get a connection to the local authentication agent (this may again
|
|
* get forwarded).
|
|
*/
|
|
sock = ssh_get_authentication_socket();
|
|
|
|
/*
|
|
* If we could not connect the agent, send an error message back to
|
|
* the server. This should never happen unless the agent dies,
|
|
* because authentication forwarding is only enabled if we have an
|
|
* agent.
|
|
*/
|
|
if (sock >= 0) {
|
|
c = channel_new("", SSH_CHANNEL_OPEN, sock, sock,
|
|
-1, 0, 0, 0, "authentication agent connection", 1);
|
|
c->remote_id = remote_id;
|
|
c->force_drain = 1;
|
|
}
|
|
if (c == NULL) {
|
|
packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
|
|
packet_put_int(remote_id);
|
|
} else {
|
|
/* Send a confirmation to the remote host. */
|
|
debug("Forwarding authentication connection.");
|
|
packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
|
|
packet_put_int(remote_id);
|
|
packet_put_int(c->self);
|
|
}
|
|
packet_send();
|
|
}
|