2000-02-24 14:29:47 +00:00
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/*
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*
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* channels.c
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*
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* Author: Tatu Ylonen <ylo@cs.hut.fi>
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*
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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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*
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* Created: Fri Mar 24 16:35:24 1995 ylo
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*
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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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*/
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#include "includes.h"
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2000-03-26 07:07:24 +00:00
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RCSID("$Id: channels.c,v 1.39 2000/03/16 20:56:14 markus Exp $");
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2000-02-24 14:29:47 +00:00
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#include "ssh.h"
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#include "packet.h"
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#include "xmalloc.h"
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#include "buffer.h"
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#include "authfd.h"
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#include "uidswap.h"
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#include "readconf.h"
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#include "servconf.h"
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#include "channels.h"
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#include "nchan.h"
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#include "compat.h"
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/* Maximum number of fake X11 displays to try. */
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#define MAX_DISPLAYS 1000
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/* Max len of agent socket */
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#define MAX_SOCKET_NAME 100
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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 are marked with type
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* SSH_CHANNEL_FREE.
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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_allocate.
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*/
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static int channel_max_fd_value = 0;
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/* Name and directory of socket for authentication agent forwarding. */
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static char *channel_forwarded_auth_socket_name = NULL;
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static char *channel_forwarded_auth_socket_dir = NULL;
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/* Saved X11 authentication protocol name. */
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char *x11_saved_proto = NULL;
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/* Saved X11 authentication data. This is the real data. */
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char *x11_saved_data = NULL;
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unsigned 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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char *x11_fake_data = NULL;
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unsigned int x11_fake_data_len;
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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; /* Host name. */
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u_short port; /* 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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/* This is set to true if both sides support SSH_PROTOFLAG_HOST_IN_FWD_OPEN. */
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static int have_hostname_in_open = 0;
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/* Sets specific protocol options. */
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void
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channel_set_options(int hostname_in_open)
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{
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have_hostname_in_open = hostname_in_open;
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}
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/*
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* Permits opening to any host/port in SSH_MSG_PORT_OPEN. This is usually
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* called by the server, because the user could connect to any port anyway,
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* and the server has no way to know but to trust the client anyway.
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*/
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void
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channel_permit_all_opens()
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{
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all_opens_permitted = 1;
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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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int
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channel_allocate(int type, int sock, char *remote_name)
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{
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int i, found;
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Channel *c;
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/* Update the maximum file descriptor value. */
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if (sock > channel_max_fd_value)
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channel_max_fd_value = sock;
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/* XXX set close-on-exec -markus */
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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].type = SSH_CHANNEL_FREE;
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/*
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* Kludge: arrange a call to channel_stop_listening if we
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* terminate with fatal().
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*/
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fatal_add_cleanup((void (*) (void *)) channel_stop_listening, 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].type == SSH_CHANNEL_FREE) {
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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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debug("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].type = SSH_CHANNEL_FREE;
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}
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/* Initialize and return new channel number. */
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c = &channels[found];
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buffer_init(&c->input);
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buffer_init(&c->output);
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chan_init_iostates(c);
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c->self = found;
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c->type = type;
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c->sock = sock;
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c->remote_id = -1;
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c->remote_name = remote_name;
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debug("channel %d: new [%s]", found, remote_name);
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return found;
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}
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/* Free the channel and close its socket. */
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void
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channel_free(int channel)
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{
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if (channel < 0 || channel >= channels_alloc ||
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channels[channel].type == SSH_CHANNEL_FREE)
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packet_disconnect("channel free: bad local channel %d", channel);
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if (compat13)
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shutdown(channels[channel].sock, SHUT_RDWR);
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close(channels[channel].sock);
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buffer_free(&channels[channel].input);
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buffer_free(&channels[channel].output);
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channels[channel].type = SSH_CHANNEL_FREE;
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if (channels[channel].remote_name) {
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xfree(channels[channel].remote_name);
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channels[channel].remote_name = NULL;
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}
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}
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/*
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* This is called just before select() to add any bits relevant to channels
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* in the select bitmasks.
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*/
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void
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channel_prepare_select(fd_set * readset, fd_set * writeset)
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{
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int i;
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Channel *ch;
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unsigned char *ucp;
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unsigned int proto_len, data_len;
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for (i = 0; i < channels_alloc; i++) {
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ch = &channels[i];
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redo:
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switch (ch->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_AUTH_SOCKET:
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FD_SET(ch->sock, readset);
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break;
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case SSH_CHANNEL_OPEN:
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if (compat13) {
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if (buffer_len(&ch->input) < packet_get_maxsize())
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FD_SET(ch->sock, readset);
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if (buffer_len(&ch->output) > 0)
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FD_SET(ch->sock, writeset);
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break;
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}
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/* test whether sockets are 'alive' for read/write */
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if (ch->istate == CHAN_INPUT_OPEN)
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if (buffer_len(&ch->input) < packet_get_maxsize())
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FD_SET(ch->sock, readset);
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if (ch->ostate == CHAN_OUTPUT_OPEN ||
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ch->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
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if (buffer_len(&ch->output) > 0) {
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FD_SET(ch->sock, writeset);
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} else if (ch->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
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chan_obuf_empty(ch);
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}
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}
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break;
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case SSH_CHANNEL_INPUT_DRAINING:
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if (!compat13)
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fatal("cannot happen: IN_DRAIN");
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if (buffer_len(&ch->input) == 0) {
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packet_start(SSH_MSG_CHANNEL_CLOSE);
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packet_put_int(ch->remote_id);
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packet_send();
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ch->type = SSH_CHANNEL_CLOSED;
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debug("Closing channel %d after input drain.", ch->self);
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break;
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}
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break;
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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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if (buffer_len(&ch->output) == 0) {
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channel_free(i);
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break;
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}
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FD_SET(ch->sock, writeset);
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break;
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case SSH_CHANNEL_X11_OPEN:
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/*
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* This is a special state for X11 authentication
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* spoofing. An opened X11 connection (when
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* authentication spoofing is being done) remains in
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* this state until the first packet has been
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* completely read. The authentication data in that
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* packet is then substituted by the real data if it
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* matches the fake data, and the channel is put into
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* normal mode.
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*/
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/* Check if the fixed size part of the packet is in buffer. */
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if (buffer_len(&ch->output) < 12)
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break;
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/* Parse the lengths of variable-length fields. */
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ucp = (unsigned char *) buffer_ptr(&ch->output);
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if (ucp[0] == 0x42) { /* Byte order MSB first. */
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proto_len = 256 * ucp[6] + ucp[7];
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data_len = 256 * ucp[8] + ucp[9];
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} else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
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proto_len = ucp[6] + 256 * ucp[7];
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data_len = ucp[8] + 256 * ucp[9];
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} else {
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debug("Initial X11 packet contains bad byte order byte: 0x%x",
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ucp[0]);
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ch->type = SSH_CHANNEL_OPEN;
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goto reject;
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}
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/* Check if the whole packet is in buffer. */
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if (buffer_len(&ch->output) <
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12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
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break;
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/* Check if authentication protocol matches. */
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if (proto_len != strlen(x11_saved_proto) ||
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memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
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debug("X11 connection uses different authentication protocol.");
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ch->type = SSH_CHANNEL_OPEN;
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goto reject;
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}
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/* Check if authentication data matches our fake data. */
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if (data_len != x11_fake_data_len ||
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memcmp(ucp + 12 + ((proto_len + 3) & ~3),
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x11_fake_data, x11_fake_data_len) != 0) {
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debug("X11 auth data does not match fake data.");
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ch->type = SSH_CHANNEL_OPEN;
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goto reject;
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}
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/* Check fake data length */
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if (x11_fake_data_len != x11_saved_data_len) {
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error("X11 fake_data_len %d != saved_data_len %d",
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x11_fake_data_len, x11_saved_data_len);
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ch->type = SSH_CHANNEL_OPEN;
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goto reject;
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}
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/*
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* Received authentication protocol and data match
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* our fake data. Substitute the fake data with real
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* data.
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*/
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memcpy(ucp + 12 + ((proto_len + 3) & ~3),
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x11_saved_data, x11_saved_data_len);
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/* Start normal processing for the channel. */
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ch->type = SSH_CHANNEL_OPEN;
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goto redo;
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reject:
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/*
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* We have received an X11 connection that has bad
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* authentication information.
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*/
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log("X11 connection rejected because of wrong authentication.\r\n");
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buffer_clear(&ch->input);
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buffer_clear(&ch->output);
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if (compat13) {
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close(ch->sock);
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ch->sock = -1;
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ch->type = SSH_CHANNEL_CLOSED;
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packet_start(SSH_MSG_CHANNEL_CLOSE);
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packet_put_int(ch->remote_id);
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packet_send();
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} else {
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debug("X11 rejected %d i%d/o%d", ch->self, ch->istate, ch->ostate);
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chan_read_failed(ch);
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chan_write_failed(ch);
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debug("X11 rejected %d i%d/o%d", ch->self, ch->istate, ch->ostate);
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}
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break;
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case SSH_CHANNEL_FREE:
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default:
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continue;
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}
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}
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}
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/*
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* After select, perform any appropriate operations for channels which have
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* events pending.
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*/
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void
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channel_after_select(fd_set * readset, fd_set * writeset)
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{
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struct sockaddr addr;
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|
|
int newsock, i, newch, len;
|
|
|
|
socklen_t addrlen;
|
|
|
|
Channel *ch;
|
|
|
|
char buf[16384], *remote_hostname;
|
|
|
|
|
|
|
|
/* Loop over all channels... */
|
|
|
|
for (i = 0; i < channels_alloc; i++) {
|
|
|
|
ch = &channels[i];
|
|
|
|
switch (ch->type) {
|
|
|
|
case SSH_CHANNEL_X11_LISTENER:
|
|
|
|
/* This is our fake X11 server socket. */
|
|
|
|
if (FD_ISSET(ch->sock, readset)) {
|
|
|
|
debug("X11 connection requested.");
|
|
|
|
addrlen = sizeof(addr);
|
|
|
|
newsock = accept(ch->sock, &addr, &addrlen);
|
|
|
|
if (newsock < 0) {
|
|
|
|
error("accept: %.100s", strerror(errno));
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
remote_hostname = get_remote_hostname(newsock);
|
|
|
|
snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
|
|
|
|
remote_hostname, get_peer_port(newsock));
|
|
|
|
xfree(remote_hostname);
|
|
|
|
newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
|
|
|
|
xstrdup(buf));
|
|
|
|
packet_start(SSH_SMSG_X11_OPEN);
|
|
|
|
packet_put_int(newch);
|
|
|
|
if (have_hostname_in_open)
|
|
|
|
packet_put_string(buf, strlen(buf));
|
|
|
|
packet_send();
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
|
|
|
|
case SSH_CHANNEL_PORT_LISTENER:
|
|
|
|
/*
|
|
|
|
* This socket is listening for connections to a
|
|
|
|
* forwarded TCP/IP port.
|
|
|
|
*/
|
|
|
|
if (FD_ISSET(ch->sock, readset)) {
|
|
|
|
debug("Connection to port %d forwarding to %.100s port %d requested.",
|
|
|
|
ch->listening_port, ch->path, ch->host_port);
|
|
|
|
addrlen = sizeof(addr);
|
|
|
|
newsock = accept(ch->sock, &addr, &addrlen);
|
|
|
|
if (newsock < 0) {
|
|
|
|
error("accept: %.100s", strerror(errno));
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
remote_hostname = get_remote_hostname(newsock);
|
|
|
|
snprintf(buf, sizeof buf, "listen port %d for %.100s port %d, connect from %.200s port %d",
|
|
|
|
ch->listening_port, ch->path, ch->host_port,
|
|
|
|
remote_hostname, get_peer_port(newsock));
|
|
|
|
xfree(remote_hostname);
|
|
|
|
newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
|
|
|
|
xstrdup(buf));
|
|
|
|
packet_start(SSH_MSG_PORT_OPEN);
|
|
|
|
packet_put_int(newch);
|
|
|
|
packet_put_string(ch->path, strlen(ch->path));
|
|
|
|
packet_put_int(ch->host_port);
|
|
|
|
if (have_hostname_in_open)
|
|
|
|
packet_put_string(buf, strlen(buf));
|
|
|
|
packet_send();
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
|
|
|
|
case SSH_CHANNEL_AUTH_SOCKET:
|
|
|
|
/*
|
|
|
|
* This is the authentication agent socket listening
|
|
|
|
* for connections from clients.
|
|
|
|
*/
|
|
|
|
if (FD_ISSET(ch->sock, readset)) {
|
|
|
|
addrlen = sizeof(addr);
|
|
|
|
newsock = accept(ch->sock, &addr, &addrlen);
|
|
|
|
if (newsock < 0) {
|
|
|
|
error("accept from auth socket: %.100s", strerror(errno));
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
newch = channel_allocate(SSH_CHANNEL_OPENING, newsock,
|
|
|
|
xstrdup("accepted auth socket"));
|
|
|
|
packet_start(SSH_SMSG_AGENT_OPEN);
|
|
|
|
packet_put_int(newch);
|
|
|
|
packet_send();
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
|
|
|
|
case SSH_CHANNEL_OPEN:
|
|
|
|
/*
|
|
|
|
* This is an open two-way communication channel. It
|
|
|
|
* is not of interest to us at this point what kind
|
|
|
|
* of data is being transmitted.
|
|
|
|
*/
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Read available incoming data and append it to
|
|
|
|
* buffer; shutdown socket, if read or write failes
|
|
|
|
*/
|
|
|
|
if (FD_ISSET(ch->sock, readset)) {
|
|
|
|
len = read(ch->sock, buf, sizeof(buf));
|
|
|
|
if (len <= 0) {
|
|
|
|
if (compat13) {
|
|
|
|
buffer_consume(&ch->output, buffer_len(&ch->output));
|
|
|
|
ch->type = SSH_CHANNEL_INPUT_DRAINING;
|
|
|
|
debug("Channel %d status set to input draining.", i);
|
|
|
|
} else {
|
|
|
|
chan_read_failed(ch);
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
buffer_append(&ch->input, buf, len);
|
|
|
|
}
|
|
|
|
/* Send buffered output data to the socket. */
|
|
|
|
if (FD_ISSET(ch->sock, writeset) && buffer_len(&ch->output) > 0) {
|
|
|
|
len = write(ch->sock, buffer_ptr(&ch->output),
|
|
|
|
buffer_len(&ch->output));
|
|
|
|
if (len <= 0) {
|
|
|
|
if (compat13) {
|
|
|
|
buffer_consume(&ch->output, buffer_len(&ch->output));
|
|
|
|
debug("Channel %d status set to input draining.", i);
|
|
|
|
ch->type = SSH_CHANNEL_INPUT_DRAINING;
|
|
|
|
} else {
|
|
|
|
chan_write_failed(ch);
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
buffer_consume(&ch->output, len);
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
|
|
|
|
case SSH_CHANNEL_OUTPUT_DRAINING:
|
|
|
|
if (!compat13)
|
|
|
|
fatal("cannot happen: OUT_DRAIN");
|
|
|
|
/* Send buffered output data to the socket. */
|
|
|
|
if (FD_ISSET(ch->sock, writeset) && buffer_len(&ch->output) > 0) {
|
|
|
|
len = write(ch->sock, buffer_ptr(&ch->output),
|
|
|
|
buffer_len(&ch->output));
|
|
|
|
if (len <= 0)
|
|
|
|
buffer_consume(&ch->output, buffer_len(&ch->output));
|
|
|
|
else
|
|
|
|
buffer_consume(&ch->output, len);
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
|
|
|
|
case SSH_CHANNEL_X11_OPEN:
|
|
|
|
case SSH_CHANNEL_FREE:
|
|
|
|
default:
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/* If there is data to send to the connection, send some of it now. */
|
|
|
|
|
|
|
|
void
|
|
|
|
channel_output_poll()
|
|
|
|
{
|
|
|
|
int len, i;
|
|
|
|
Channel *ch;
|
|
|
|
|
|
|
|
for (i = 0; i < channels_alloc; i++) {
|
|
|
|
ch = &channels[i];
|
|
|
|
|
|
|
|
/* We are only interested in channels that can have buffered incoming data. */
|
|
|
|
if (compat13) {
|
|
|
|
if (ch->type != SSH_CHANNEL_OPEN &&
|
|
|
|
ch->type != SSH_CHANNEL_INPUT_DRAINING)
|
|
|
|
continue;
|
|
|
|
} else {
|
|
|
|
if (ch->type != SSH_CHANNEL_OPEN)
|
|
|
|
continue;
|
|
|
|
if (ch->istate != CHAN_INPUT_OPEN &&
|
|
|
|
ch->istate != CHAN_INPUT_WAIT_DRAIN)
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Get the amount of buffered data for this channel. */
|
|
|
|
len = buffer_len(&ch->input);
|
|
|
|
if (len > 0) {
|
|
|
|
/* Send some data for the other side over the secure connection. */
|
|
|
|
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;
|
|
|
|
}
|
|
|
|
packet_start(SSH_MSG_CHANNEL_DATA);
|
|
|
|
packet_put_int(ch->remote_id);
|
|
|
|
packet_put_string(buffer_ptr(&ch->input), len);
|
|
|
|
packet_send();
|
|
|
|
buffer_consume(&ch->input, len);
|
|
|
|
} else if (ch->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
|
|
|
|
*/
|
|
|
|
chan_ibuf_empty(ch);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* This is called when a packet of type CHANNEL_DATA has just been received.
|
|
|
|
* The message type has already been consumed, but channel number and data is
|
|
|
|
* still there.
|
|
|
|
*/
|
|
|
|
|
|
|
|
void
|
|
|
|
channel_input_data(int payload_len)
|
|
|
|
{
|
|
|
|
int id;
|
|
|
|
char *data;
|
|
|
|
unsigned int data_len;
|
|
|
|
Channel *ch;
|
|
|
|
|
|
|
|
/* Get the channel number and verify it. */
|
|
|
|
id = packet_get_int();
|
|
|
|
if (id < 0 || id >= channels_alloc)
|
|
|
|
packet_disconnect("Received data for nonexistent channel %d.", id);
|
|
|
|
ch = &channels[id];
|
|
|
|
|
|
|
|
if (ch->type == SSH_CHANNEL_FREE)
|
|
|
|
packet_disconnect("Received data for free channel %d.", ch->self);
|
|
|
|
|
|
|
|
/* Ignore any data for non-open channels (might happen on close) */
|
|
|
|
if (ch->type != SSH_CHANNEL_OPEN &&
|
|
|
|
ch->type != SSH_CHANNEL_X11_OPEN)
|
|
|
|
return;
|
|
|
|
|
|
|
|
/* same for protocol 1.5 if output end is no longer open */
|
|
|
|
if (!compat13 && ch->ostate != CHAN_OUTPUT_OPEN)
|
|
|
|
return;
|
|
|
|
|
|
|
|
/* Get the data. */
|
|
|
|
data = packet_get_string(&data_len);
|
|
|
|
packet_integrity_check(payload_len, 4 + 4 + data_len, SSH_MSG_CHANNEL_DATA);
|
|
|
|
buffer_append(&ch->output, data, data_len);
|
|
|
|
xfree(data);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Returns true if no channel has too much buffered data, and false if one or
|
|
|
|
* more channel is overfull.
|
|
|
|
*/
|
|
|
|
|
|
|
|
int
|
|
|
|
channel_not_very_much_buffered_data()
|
|
|
|
{
|
|
|
|
unsigned int i;
|
|
|
|
Channel *ch;
|
|
|
|
|
|
|
|
for (i = 0; i < channels_alloc; i++) {
|
|
|
|
ch = &channels[i];
|
|
|
|
if (ch->type == SSH_CHANNEL_OPEN) {
|
|
|
|
if (buffer_len(&ch->input) > packet_get_maxsize())
|
|
|
|
return 0;
|
|
|
|
if (buffer_len(&ch->output) > packet_get_maxsize())
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* This is called after receiving CHANNEL_CLOSE/IEOF. */
|
|
|
|
|
|
|
|
void
|
|
|
|
channel_input_close()
|
|
|
|
{
|
|
|
|
int channel;
|
|
|
|
|
|
|
|
/* Get the channel number and verify it. */
|
|
|
|
channel = packet_get_int();
|
|
|
|
if (channel < 0 || channel >= channels_alloc ||
|
|
|
|
channels[channel].type == SSH_CHANNEL_FREE)
|
|
|
|
packet_disconnect("Received data for nonexistent channel %d.", channel);
|
|
|
|
|
|
|
|
if (!compat13) {
|
|
|
|
/* proto version 1.5 overloads CLOSE with IEOF */
|
|
|
|
chan_rcvd_ieof(&channels[channel]);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* 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(channels[channel].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 (channels[channel].type != SSH_CHANNEL_CLOSED) {
|
|
|
|
/*
|
|
|
|
* Not a closed channel - mark it as draining, which will
|
|
|
|
* cause it to be freed later.
|
|
|
|
*/
|
|
|
|
buffer_consume(&channels[channel].input,
|
|
|
|
buffer_len(&channels[channel].input));
|
|
|
|
channels[channel].type = SSH_CHANNEL_OUTPUT_DRAINING;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/* This is called after receiving CHANNEL_CLOSE_CONFIRMATION/OCLOSE. */
|
|
|
|
|
|
|
|
void
|
|
|
|
channel_input_close_confirmation()
|
|
|
|
{
|
|
|
|
int channel;
|
|
|
|
|
|
|
|
/* Get the channel number and verify it. */
|
|
|
|
channel = packet_get_int();
|
|
|
|
if (channel < 0 || channel >= channels_alloc)
|
|
|
|
packet_disconnect("Received close confirmation for out-of-range channel %d.",
|
|
|
|
channel);
|
|
|
|
|
|
|
|
if (!compat13) {
|
|
|
|
/* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */
|
|
|
|
chan_rcvd_oclose(&channels[channel]);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
if (channels[channel].type != SSH_CHANNEL_CLOSED)
|
|
|
|
packet_disconnect("Received close confirmation for non-closed channel %d (type %d).",
|
|
|
|
channel, channels[channel].type);
|
|
|
|
|
|
|
|
/* Free the channel. */
|
|
|
|
channel_free(channel);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* This is called after receiving CHANNEL_OPEN_CONFIRMATION. */
|
|
|
|
|
|
|
|
void
|
|
|
|
channel_input_open_confirmation()
|
|
|
|
{
|
|
|
|
int channel, remote_channel;
|
|
|
|
|
|
|
|
/* Get the channel number and verify it. */
|
|
|
|
channel = packet_get_int();
|
|
|
|
if (channel < 0 || channel >= channels_alloc ||
|
|
|
|
channels[channel].type != SSH_CHANNEL_OPENING)
|
|
|
|
packet_disconnect("Received open confirmation for non-opening channel %d.",
|
|
|
|
channel);
|
|
|
|
|
|
|
|
/* Get remote side's id for this channel. */
|
|
|
|
remote_channel = packet_get_int();
|
|
|
|
|
|
|
|
/* Record the remote channel number and mark that the channel is now open. */
|
|
|
|
channels[channel].remote_id = remote_channel;
|
|
|
|
channels[channel].type = SSH_CHANNEL_OPEN;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* This is called after receiving CHANNEL_OPEN_FAILURE from the other side. */
|
|
|
|
|
|
|
|
void
|
|
|
|
channel_input_open_failure()
|
|
|
|
{
|
|
|
|
int channel;
|
|
|
|
|
|
|
|
/* Get the channel number and verify it. */
|
|
|
|
channel = packet_get_int();
|
|
|
|
if (channel < 0 || channel >= channels_alloc ||
|
|
|
|
channels[channel].type != SSH_CHANNEL_OPENING)
|
|
|
|
packet_disconnect("Received open failure for non-opening channel %d.",
|
|
|
|
channel);
|
|
|
|
|
|
|
|
/* Free the channel. This will also close the socket. */
|
|
|
|
channel_free(channel);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Stops listening for channels, and removes any unix domain sockets that we
|
|
|
|
* might have.
|
|
|
|
*/
|
|
|
|
|
|
|
|
void
|
|
|
|
channel_stop_listening()
|
|
|
|
{
|
|
|
|
int i;
|
|
|
|
for (i = 0; i < channels_alloc; i++) {
|
|
|
|
switch (channels[i].type) {
|
|
|
|
case SSH_CHANNEL_AUTH_SOCKET:
|
|
|
|
close(channels[i].sock);
|
|
|
|
remove(channels[i].path);
|
|
|
|
channel_free(i);
|
|
|
|
break;
|
|
|
|
case SSH_CHANNEL_PORT_LISTENER:
|
|
|
|
case SSH_CHANNEL_X11_LISTENER:
|
|
|
|
close(channels[i].sock);
|
|
|
|
channel_free(i);
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Closes the sockets of all channels. This is used to close extra file
|
|
|
|
* descriptors after a fork.
|
|
|
|
*/
|
|
|
|
|
|
|
|
void
|
|
|
|
channel_close_all()
|
|
|
|
{
|
|
|
|
int i;
|
|
|
|
for (i = 0; i < channels_alloc; i++) {
|
|
|
|
if (channels[i].type != SSH_CHANNEL_FREE)
|
|
|
|
close(channels[i].sock);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Returns the maximum file descriptor number used by the channels. */
|
|
|
|
|
|
|
|
int
|
|
|
|
channel_max_fd()
|
|
|
|
{
|
|
|
|
return channel_max_fd_value;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Returns true if any channel is still open. */
|
|
|
|
|
|
|
|
int
|
|
|
|
channel_still_open()
|
|
|
|
{
|
|
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < channels_alloc; i++)
|
|
|
|
switch (channels[i].type) {
|
|
|
|
case SSH_CHANNEL_FREE:
|
|
|
|
case SSH_CHANNEL_X11_LISTENER:
|
|
|
|
case SSH_CHANNEL_PORT_LISTENER:
|
|
|
|
case SSH_CHANNEL_CLOSED:
|
|
|
|
case SSH_CHANNEL_AUTH_SOCKET:
|
|
|
|
continue;
|
|
|
|
case SSH_CHANNEL_OPENING:
|
|
|
|
case SSH_CHANNEL_OPEN:
|
|
|
|
case SSH_CHANNEL_X11_OPEN:
|
|
|
|
return 1;
|
|
|
|
case SSH_CHANNEL_INPUT_DRAINING:
|
|
|
|
case SSH_CHANNEL_OUTPUT_DRAINING:
|
|
|
|
if (!compat13)
|
|
|
|
fatal("cannot happen: OUT_DRAIN");
|
|
|
|
return 1;
|
|
|
|
default:
|
|
|
|
fatal("channel_still_open: bad channel type %d", channels[i].type);
|
|
|
|
/* NOTREACHED */
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Returns a message describing the currently open forwarded connections,
|
|
|
|
* suitable for sending to the client. The message contains crlf pairs for
|
|
|
|
* newlines.
|
|
|
|
*/
|
|
|
|
|
|
|
|
char *
|
|
|
|
channel_open_message()
|
|
|
|
{
|
|
|
|
Buffer buffer;
|
|
|
|
int i;
|
|
|
|
char buf[512], *cp;
|
|
|
|
|
|
|
|
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++) {
|
|
|
|
Channel *c = &channels[i];
|
|
|
|
switch (c->type) {
|
|
|
|
case SSH_CHANNEL_FREE:
|
|
|
|
case SSH_CHANNEL_X11_LISTENER:
|
|
|
|
case SSH_CHANNEL_PORT_LISTENER:
|
|
|
|
case SSH_CHANNEL_CLOSED:
|
|
|
|
case SSH_CHANNEL_AUTH_SOCKET:
|
|
|
|
continue;
|
|
|
|
case SSH_CHANNEL_OPENING:
|
|
|
|
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)\r\n",
|
|
|
|
c->self, c->remote_name,
|
|
|
|
c->type, c->remote_id,
|
|
|
|
c->istate, buffer_len(&c->input),
|
|
|
|
c->ostate, buffer_len(&c->output));
|
|
|
|
buffer_append(&buffer, buf, strlen(buf));
|
|
|
|
continue;
|
|
|
|
default:
|
|
|
|
fatal("channel_still_open: bad channel type %d", c->type);
|
|
|
|
/* NOTREACHED */
|
|
|
|
}
|
|
|
|
}
|
|
|
|
buffer_append(&buffer, "\0", 1);
|
|
|
|
cp = xstrdup(buffer_ptr(&buffer));
|
|
|
|
buffer_free(&buffer);
|
|
|
|
return cp;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Initiate forwarding of connections to local port "port" through the secure
|
|
|
|
* channel to host:port from remote side.
|
|
|
|
*/
|
|
|
|
|
|
|
|
void
|
|
|
|
channel_request_local_forwarding(u_short port, const char *host,
|
|
|
|
u_short host_port, int gateway_ports)
|
|
|
|
{
|
|
|
|
int success, ch, sock, on = 1;
|
|
|
|
struct addrinfo hints, *ai, *aitop;
|
|
|
|
char ntop[NI_MAXHOST], strport[NI_MAXSERV];
|
|
|
|
struct linger linger;
|
|
|
|
|
|
|
|
if (strlen(host) > sizeof(channels[0].path) - 1)
|
|
|
|
packet_disconnect("Forward host name too long.");
|
|
|
|
|
|
|
|
/*
|
|
|
|
* 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", port);
|
|
|
|
if (getaddrinfo(NULL, strport, &hints, &aitop) != 0)
|
|
|
|
packet_disconnect("getaddrinfo: fatal error");
|
|
|
|
|
|
|
|
success = 0;
|
|
|
|
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_request_local_forwarding: getnameinfo failed");
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
/* Create a port to listen for the host. */
|
|
|
|
sock = socket(ai->ai_family, SOCK_STREAM, 0);
|
|
|
|
if (sock < 0) {
|
|
|
|
/* this is no error since kernel may not support ipv6 */
|
|
|
|
verbose("socket: %.100s", strerror(errno));
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
/*
|
|
|
|
* Set socket options. We would like the socket to disappear
|
|
|
|
* as soon as it has been closed for whatever reason.
|
|
|
|
*/
|
|
|
|
setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on));
|
|
|
|
linger.l_onoff = 1;
|
|
|
|
linger.l_linger = 5;
|
|
|
|
setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
|
|
|
|
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 */
|
|
|
|
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. */
|
|
|
|
ch = channel_allocate(SSH_CHANNEL_PORT_LISTENER, sock,
|
|
|
|
xstrdup("port listener"));
|
|
|
|
strlcpy(channels[ch].path, host, sizeof(channels[ch].path));
|
|
|
|
channels[ch].host_port = host_port;
|
|
|
|
channels[ch].listening_port = port;
|
|
|
|
success = 1;
|
|
|
|
}
|
|
|
|
if (success == 0)
|
|
|
|
packet_disconnect("cannot listen port: %d", port);
|
|
|
|
freeaddrinfo(aitop);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* 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 port, const char *host,
|
|
|
|
u_short remote_port)
|
|
|
|
{
|
|
|
|
int payload_len;
|
|
|
|
/* 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");
|
|
|
|
|
|
|
|
permitted_opens[num_permitted_opens].host = xstrdup(host);
|
|
|
|
permitted_opens[num_permitted_opens].port = remote_port;
|
|
|
|
num_permitted_opens++;
|
|
|
|
|
|
|
|
/* Send the forward request to the remote side. */
|
|
|
|
packet_start(SSH_CMSG_PORT_FORWARD_REQUEST);
|
|
|
|
packet_put_int(port);
|
|
|
|
packet_put_string(host, strlen(host));
|
|
|
|
packet_put_int(remote_port);
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Wait for response from the remote side. It will send a disconnect
|
|
|
|
* message on failure, and we will never see it here.
|
|
|
|
*/
|
|
|
|
packet_read_expect(&payload_len, SSH_SMSG_SUCCESS);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* 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)
|
|
|
|
{
|
|
|
|
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();
|
|
|
|
|
|
|
|
/*
|
|
|
|
* 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);
|
|
|
|
/*
|
|
|
|
* Initiate forwarding,
|
|
|
|
* bind port to localhost only (gateway ports == 0).
|
|
|
|
*/
|
|
|
|
channel_request_local_forwarding(port, hostname, host_port, 0);
|
|
|
|
|
|
|
|
/* Free the argument string. */
|
|
|
|
xfree(hostname);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* This is called after receiving PORT_OPEN message. This attempts to
|
|
|
|
* connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION
|
|
|
|
* or CHANNEL_OPEN_FAILURE.
|
|
|
|
*/
|
|
|
|
|
|
|
|
void
|
|
|
|
channel_input_port_open(int payload_len)
|
|
|
|
{
|
|
|
|
int remote_channel, sock = 0, newch, i;
|
|
|
|
u_short host_port;
|
|
|
|
char *host, *originator_string;
|
2000-03-26 07:07:24 +00:00
|
|
|
unsigned int host_len, originator_len;
|
2000-02-24 14:29:47 +00:00
|
|
|
struct addrinfo hints, *ai, *aitop;
|
|
|
|
char ntop[NI_MAXHOST], strport[NI_MAXSERV];
|
|
|
|
int gaierr;
|
|
|
|
|
|
|
|
/* Get remote channel number. */
|
|
|
|
remote_channel = packet_get_int();
|
|
|
|
|
|
|
|
/* Get host name to connect to. */
|
|
|
|
host = packet_get_string(&host_len);
|
|
|
|
|
|
|
|
/* Get port to connect to. */
|
|
|
|
host_port = packet_get_int();
|
|
|
|
|
|
|
|
/* Get remote originator name. */
|
|
|
|
if (have_hostname_in_open) {
|
|
|
|
originator_string = packet_get_string(&originator_len);
|
|
|
|
originator_len += 4; /* size of packet_int */
|
|
|
|
} else {
|
|
|
|
originator_string = xstrdup("unknown (remote did not supply name)");
|
|
|
|
originator_len = 0; /* no originator supplied */
|
|
|
|
}
|
|
|
|
|
|
|
|
packet_integrity_check(payload_len,
|
|
|
|
4 + 4 + host_len + 4 + originator_len,
|
|
|
|
SSH_MSG_PORT_OPEN);
|
|
|
|
|
|
|
|
/* Check if opening that port is permitted. */
|
|
|
|
if (!all_opens_permitted) {
|
|
|
|
/* Go trough all permitted ports. */
|
|
|
|
for (i = 0; i < num_permitted_opens; i++)
|
|
|
|
if (permitted_opens[i].port == host_port &&
|
|
|
|
strcmp(permitted_opens[i].host, host) == 0)
|
|
|
|
break;
|
|
|
|
|
|
|
|
/* Check if we found the requested port among those permitted. */
|
|
|
|
if (i >= num_permitted_opens) {
|
|
|
|
/* The port is not permitted. */
|
|
|
|
log("Received request to connect to %.100s:%d, but the request was denied.",
|
|
|
|
host, host_port);
|
|
|
|
goto fail;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
memset(&hints, 0, sizeof(hints));
|
|
|
|
hints.ai_family = IPv4or6;
|
|
|
|
hints.ai_socktype = SOCK_STREAM;
|
|
|
|
snprintf(strport, sizeof strport, "%d", host_port);
|
|
|
|
if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
|
|
|
|
error("%.100s: unknown host (%s)", host, gai_strerror(gaierr));
|
|
|
|
goto fail;
|
|
|
|
}
|
|
|
|
|
|
|
|
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_input_port_open: getnameinfo failed");
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
/* Create the socket. */
|
|
|
|
sock = socket(ai->ai_family, SOCK_STREAM, 0);
|
|
|
|
if (sock < 0) {
|
|
|
|
error("socket: %.100s", strerror(errno));
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
/* Connect to the host/port. */
|
|
|
|
if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
|
|
|
|
error("connect %.100s port %s: %.100s", ntop, strport,
|
|
|
|
strerror(errno));
|
|
|
|
close(sock);
|
|
|
|
continue; /* fail -- try next */
|
|
|
|
}
|
|
|
|
break; /* success */
|
|
|
|
|
|
|
|
}
|
|
|
|
freeaddrinfo(aitop);
|
|
|
|
|
|
|
|
if (!ai) {
|
|
|
|
error("connect %.100s port %d: failed.", host, host_port);
|
|
|
|
goto fail;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Successful connection. */
|
|
|
|
|
|
|
|
/* Allocate a channel for this connection. */
|
|
|
|
newch = channel_allocate(SSH_CHANNEL_OPEN, sock, originator_string);
|
|
|
|
channels[newch].remote_id = remote_channel;
|
|
|
|
|
|
|
|
/* Send a confirmation to the remote host. */
|
|
|
|
packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
|
|
|
|
packet_put_int(remote_channel);
|
|
|
|
packet_put_int(newch);
|
|
|
|
packet_send();
|
|
|
|
|
|
|
|
/* Free the argument string. */
|
|
|
|
xfree(host);
|
|
|
|
|
|
|
|
return;
|
|
|
|
|
|
|
|
fail:
|
|
|
|
/* Free the argument string. */
|
|
|
|
xfree(host);
|
|
|
|
|
|
|
|
/* Send refusal to the remote host. */
|
|
|
|
packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
|
|
|
|
packet_put_int(remote_channel);
|
|
|
|
packet_send();
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Creates an internet domain socket for listening for X11 connections.
|
|
|
|
* Returns a suitable value for the DISPLAY variable, or NULL if an error
|
|
|
|
* occurs.
|
|
|
|
*/
|
|
|
|
|
|
|
|
#define NUM_SOCKS 10
|
|
|
|
|
|
|
|
char *
|
|
|
|
x11_create_display_inet(int screen_number, int x11_display_offset)
|
|
|
|
{
|
|
|
|
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];
|
|
|
|
char display[512];
|
|
|
|
char hostname[MAXHOSTNAMELEN];
|
|
|
|
|
|
|
|
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 = AI_PASSIVE; /* XXX loopback only ? */
|
|
|
|
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 NULL;
|
|
|
|
}
|
|
|
|
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, SOCK_STREAM, 0);
|
|
|
|
if (sock < 0) {
|
|
|
|
error("socket: %.100s", strerror(errno));
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
|
|
|
|
debug("bind port %d: %.100s", port, strerror(errno));
|
|
|
|
shutdown(sock, SHUT_RDWR);
|
|
|
|
close(sock);
|
|
|
|
for (n = 0; n < num_socks; n++) {
|
|
|
|
shutdown(socks[n], SHUT_RDWR);
|
|
|
|
close(socks[n]);
|
|
|
|
}
|
|
|
|
num_socks = 0;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
socks[num_socks++] = sock;
|
|
|
|
if (num_socks == NUM_SOCKS)
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
if (num_socks > 0)
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
if (display_number >= MAX_DISPLAYS) {
|
|
|
|
error("Failed to allocate internet-domain X11 display socket.");
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
/* 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));
|
|
|
|
shutdown(sock, SHUT_RDWR);
|
|
|
|
close(sock);
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Set up a suitable value for the DISPLAY variable. */
|
|
|
|
if (gethostname(hostname, sizeof(hostname)) < 0)
|
|
|
|
fatal("gethostname: %.100s", strerror(errno));
|
|
|
|
snprintf(display, sizeof display, "%.400s:%d.%d", hostname,
|
|
|
|
display_number, screen_number);
|
|
|
|
|
|
|
|
/* Allocate a channel for each socket. */
|
|
|
|
for (n = 0; n < num_socks; n++) {
|
|
|
|
sock = socks[n];
|
|
|
|
(void) channel_allocate(SSH_CHANNEL_X11_LISTENER, sock,
|
|
|
|
xstrdup("X11 inet listener"));
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Return a suitable value for the DISPLAY environment variable. */
|
|
|
|
return xstrdup(display);
|
|
|
|
}
|
|
|
|
|
|
|
|
#ifndef X_UNIX_PATH
|
|
|
|
#define X_UNIX_PATH "/tmp/.X11-unix/X"
|
|
|
|
#endif
|
|
|
|
|
|
|
|
static
|
|
|
|
int
|
|
|
|
connect_local_xsocket(unsigned int dnr)
|
|
|
|
{
|
|
|
|
static const char *const x_sockets[] = {
|
|
|
|
X_UNIX_PATH "%u",
|
|
|
|
"/var/X/.X11-unix/X" "%u",
|
|
|
|
"/usr/spool/sockets/X11/" "%u",
|
|
|
|
NULL
|
|
|
|
};
|
|
|
|
int sock;
|
|
|
|
struct sockaddr_un addr;
|
|
|
|
const char *const * path;
|
|
|
|
|
|
|
|
for (path = x_sockets; *path; ++path) {
|
|
|
|
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, 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;
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
* 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 payload_len)
|
|
|
|
{
|
|
|
|
int remote_channel, display_number, sock = 0, newch;
|
|
|
|
const char *display;
|
|
|
|
char buf[1024], *cp, *remote_host;
|
2000-03-26 07:07:24 +00:00
|
|
|
unsigned int remote_len;
|
2000-02-24 14:29:47 +00:00
|
|
|
struct addrinfo hints, *ai, *aitop;
|
|
|
|
char strport[NI_MAXSERV];
|
|
|
|
int gaierr;
|
|
|
|
|
|
|
|
/* Get remote channel number. */
|
|
|
|
remote_channel = packet_get_int();
|
|
|
|
|
|
|
|
/* Get remote originator name. */
|
|
|
|
if (have_hostname_in_open) {
|
|
|
|
remote_host = packet_get_string(&remote_len);
|
|
|
|
remote_len += 4;
|
|
|
|
} else {
|
|
|
|
remote_host = xstrdup("unknown (remote did not supply name)");
|
|
|
|
remote_len = 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
debug("Received X11 open request.");
|
|
|
|
packet_integrity_check(payload_len, 4 + remote_len, SSH_SMSG_X11_OPEN);
|
|
|
|
|
|
|
|
/* Try to open a socket for the local X server. */
|
|
|
|
display = getenv("DISPLAY");
|
|
|
|
if (!display) {
|
|
|
|
error("DISPLAY not set.");
|
|
|
|
goto fail;
|
|
|
|
}
|
|
|
|
/*
|
|
|
|
* 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);
|
|
|
|
goto fail;
|
|
|
|
}
|
|
|
|
/* Create a socket. */
|
|
|
|
sock = connect_local_xsocket(display_number);
|
|
|
|
if (sock < 0)
|
|
|
|
goto fail;
|
|
|
|
|
|
|
|
/* OK, we now have a connection to the display. */
|
|
|
|
goto success;
|
|
|
|
}
|
|
|
|
/*
|
|
|
|
* Connect to an inet socket. The DISPLAY value is supposedly
|
|
|
|
* hostname:d[.s], where hostname may also be numeric IP address.
|
|
|
|
*/
|
|
|
|
strncpy(buf, display, sizeof(buf));
|
|
|
|
buf[sizeof(buf) - 1] = 0;
|
|
|
|
cp = strchr(buf, ':');
|
|
|
|
if (!cp) {
|
|
|
|
error("Could not find ':' in DISPLAY: %.100s", display);
|
|
|
|
goto fail;
|
|
|
|
}
|
|
|
|
*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);
|
|
|
|
goto fail;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* 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));
|
|
|
|
goto fail;
|
|
|
|
}
|
|
|
|
for (ai = aitop; ai; ai = ai->ai_next) {
|
|
|
|
/* Create a socket. */
|
|
|
|
sock = socket(ai->ai_family, SOCK_STREAM, 0);
|
|
|
|
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;
|
|
|
|
|
|
|
|
} /* (ai = aitop, ai; ai = ai->ai_next) */
|
|
|
|
freeaddrinfo(aitop);
|
|
|
|
if (!ai) {
|
|
|
|
error("connect %.100s port %d: %.100s", buf, 6000 + display_number,
|
|
|
|
strerror(errno));
|
|
|
|
goto fail;
|
|
|
|
}
|
|
|
|
success:
|
|
|
|
/* We have successfully obtained a connection to the real X display. */
|
|
|
|
|
|
|
|
/* Allocate a channel for this connection. */
|
|
|
|
if (x11_saved_proto == NULL)
|
|
|
|
newch = channel_allocate(SSH_CHANNEL_OPEN, sock, remote_host);
|
|
|
|
else
|
|
|
|
newch = channel_allocate(SSH_CHANNEL_X11_OPEN, sock, remote_host);
|
|
|
|
channels[newch].remote_id = remote_channel;
|
|
|
|
|
|
|
|
/* Send a confirmation to the remote host. */
|
|
|
|
packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
|
|
|
|
packet_put_int(remote_channel);
|
|
|
|
packet_put_int(newch);
|
|
|
|
packet_send();
|
|
|
|
|
|
|
|
return;
|
|
|
|
|
|
|
|
fail:
|
|
|
|
/* Send refusal to the remote host. */
|
|
|
|
packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
|
|
|
|
packet_put_int(remote_channel);
|
|
|
|
packet_send();
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Requests forwarding of X11 connections, generates fake authentication
|
|
|
|
* data, and enables authentication spoofing.
|
|
|
|
*/
|
|
|
|
|
|
|
|
void
|
|
|
|
x11_request_forwarding_with_spoofing(const char *proto, const char *data)
|
|
|
|
{
|
|
|
|
unsigned int data_len = (unsigned int) strlen(data) / 2;
|
|
|
|
unsigned int i, value;
|
|
|
|
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. */
|
|
|
|
new_data = xmalloc(2 * data_len + 1);
|
|
|
|
for (i = 0; i < data_len; i++)
|
|
|
|
sprintf(new_data + 2 * i, "%02x", (unsigned char) x11_fake_data[i]);
|
|
|
|
|
|
|
|
/* Send the request packet. */
|
|
|
|
packet_start(SSH_CMSG_X11_REQUEST_FORWARDING);
|
|
|
|
packet_put_string(proto, strlen(proto));
|
|
|
|
packet_put_string(new_data, strlen(new_data));
|
|
|
|
packet_put_int(screen_number);
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
xfree(new_data);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Sends a message to the server to request authentication fd forwarding. */
|
|
|
|
|
|
|
|
void
|
|
|
|
auth_request_forwarding()
|
|
|
|
{
|
|
|
|
packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING);
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Returns the name of the forwarded authentication socket. Returns NULL if
|
|
|
|
* there is no forwarded authentication socket. The returned value points to
|
|
|
|
* a static buffer.
|
|
|
|
*/
|
|
|
|
|
|
|
|
char *
|
|
|
|
auth_get_socket_name()
|
|
|
|
{
|
|
|
|
return channel_forwarded_auth_socket_name;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* removes the agent forwarding socket */
|
|
|
|
|
|
|
|
void
|
|
|
|
cleanup_socket(void)
|
|
|
|
{
|
|
|
|
remove(channel_forwarded_auth_socket_name);
|
|
|
|
rmdir(channel_forwarded_auth_socket_dir);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* This if called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
|
|
|
|
* This starts forwarding authentication requests.
|
|
|
|
*/
|
|
|
|
|
|
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void
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auth_input_request_forwarding(struct passwd * pw)
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{
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int sock, newch;
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struct sockaddr_un sunaddr;
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if (auth_get_socket_name() != NULL)
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fatal("Protocol error: authentication forwarding requested twice.");
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/* Temporarily drop privileged uid for mkdir/bind. */
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temporarily_use_uid(pw->pw_uid);
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/* Allocate a buffer for the socket name, and format the name. */
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channel_forwarded_auth_socket_name = xmalloc(MAX_SOCKET_NAME);
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channel_forwarded_auth_socket_dir = xmalloc(MAX_SOCKET_NAME);
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strlcpy(channel_forwarded_auth_socket_dir, "/tmp/ssh-XXXXXXXX", MAX_SOCKET_NAME);
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/* Create private directory for socket */
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if (mkdtemp(channel_forwarded_auth_socket_dir) == NULL)
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packet_disconnect("mkdtemp: %.100s", strerror(errno));
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snprintf(channel_forwarded_auth_socket_name, MAX_SOCKET_NAME, "%s/agent.%d",
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channel_forwarded_auth_socket_dir, (int) getpid());
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if (atexit(cleanup_socket) < 0) {
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int saved = errno;
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cleanup_socket();
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packet_disconnect("socket: %.100s", strerror(saved));
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}
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/* Create the socket. */
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sock = socket(AF_UNIX, SOCK_STREAM, 0);
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if (sock < 0)
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packet_disconnect("socket: %.100s", strerror(errno));
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/* Bind it to the name. */
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memset(&sunaddr, 0, sizeof(sunaddr));
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sunaddr.sun_family = AF_UNIX;
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strncpy(sunaddr.sun_path, channel_forwarded_auth_socket_name,
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sizeof(sunaddr.sun_path));
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if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0)
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packet_disconnect("bind: %.100s", strerror(errno));
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/* Restore the privileged uid. */
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restore_uid();
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/* Start listening on the socket. */
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if (listen(sock, 5) < 0)
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packet_disconnect("listen: %.100s", strerror(errno));
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/* Allocate a channel for the authentication agent socket. */
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newch = channel_allocate(SSH_CHANNEL_AUTH_SOCKET, sock,
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xstrdup("auth socket"));
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strlcpy(channels[newch].path, channel_forwarded_auth_socket_name,
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sizeof(channels[newch].path));
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}
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/* This is called to process an SSH_SMSG_AGENT_OPEN message. */
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void
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auth_input_open_request()
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{
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int remch, sock, newch;
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char *dummyname;
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/* Read the remote channel number from the message. */
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remch = packet_get_int();
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/*
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* Get a connection to the local authentication agent (this may again
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* get forwarded).
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*/
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sock = ssh_get_authentication_socket();
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/*
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* If we could not connect the agent, send an error message back to
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* the server. This should never happen unless the agent dies,
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* because authentication forwarding is only enabled if we have an
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* agent.
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*/
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if (sock < 0) {
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packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
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packet_put_int(remch);
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packet_send();
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return;
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}
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debug("Forwarding authentication connection.");
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/*
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* Dummy host name. This will be freed when the channel is freed; it
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* will still be valid in the packet_put_string below since the
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* channel cannot yet be freed at that point.
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*/
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dummyname = xstrdup("authentication agent connection");
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newch = channel_allocate(SSH_CHANNEL_OPEN, sock, dummyname);
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channels[newch].remote_id = remch;
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/* Send a confirmation to the remote host. */
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packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
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packet_put_int(remch);
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packet_put_int(newch);
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packet_send();
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}
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