File: [local] / src / usr.bin / ssh / channels.c (download)
Revision 1.304, Fri May 14 23:29:23 2010 UTC (14 years ago) by djm
Branch: MAIN
Changes since 1.303: +11 -5 lines
Pause the mux channel while waiting for reply from aynch callbacks.
Prevents misordering of replies if new requests arrive while waiting.
Extend channel open confirm callback to allow signalling failure
conditions as well as success. Use this to 1) fix a memory leak, 2)
start using the above pause mechanism and 3) delay sending a success/
failure message on mux slave session open until we receive a reply from
the server.
motivated by and with feedback from markus@
|
/* $OpenBSD: channels.c,v 1.304 2010/05/14 23:29:23 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
* This file contains functions for generic socket connection forwarding.
* There is also code for initiating connection forwarding for X11 connections,
* arbitrary tcp/ip connections, and the authentication agent connection.
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*
* SSH2 support added by Markus Friedl.
* Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
* Copyright (c) 1999 Dug Song. All rights reserved.
* Copyright (c) 1999 Theo de Raadt. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/un.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/queue.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <stdarg.h>
#include "xmalloc.h"
#include "ssh.h"
#include "ssh1.h"
#include "ssh2.h"
#include "packet.h"
#include "log.h"
#include "misc.h"
#include "buffer.h"
#include "channels.h"
#include "compat.h"
#include "canohost.h"
#include "key.h"
#include "authfd.h"
#include "pathnames.h"
/* -- channel core */
/*
* Pointer to an array containing all allocated channels. The array is
* dynamically extended as needed.
*/
static Channel **channels = NULL;
/*
* Size of the channel array. All slots of the array must always be
* initialized (at least the type field); unused slots set to NULL
*/
static u_int channels_alloc = 0;
/*
* Maximum file descriptor value used in any of the channels. This is
* updated in channel_new.
*/
static int channel_max_fd = 0;
/* -- tcp forwarding */
/*
* Data structure for storing which hosts are permitted for forward requests.
* The local sides of any remote forwards are stored in this array to prevent
* a corrupt remote server from accessing arbitrary TCP/IP ports on our local
* network (which might be behind a firewall).
*/
typedef struct {
char *host_to_connect; /* Connect to 'host'. */
u_short port_to_connect; /* Connect to 'port'. */
u_short listen_port; /* Remote side should listen port number. */
} ForwardPermission;
/* List of all permitted host/port pairs to connect by the user. */
static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
/* List of all permitted host/port pairs to connect by the admin. */
static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION];
/* Number of permitted host/port pairs in the array permitted by the user. */
static int num_permitted_opens = 0;
/* Number of permitted host/port pair in the array permitted by the admin. */
static int num_adm_permitted_opens = 0;
/*
* If this is true, all opens are permitted. This is the case on the server
* on which we have to trust the client anyway, and the user could do
* anything after logging in anyway.
*/
static int all_opens_permitted = 0;
/* -- X11 forwarding */
/* Maximum number of fake X11 displays to try. */
#define MAX_DISPLAYS 1000
/* Saved X11 local (client) display. */
static char *x11_saved_display = NULL;
/* Saved X11 authentication protocol name. */
static char *x11_saved_proto = NULL;
/* Saved X11 authentication data. This is the real data. */
static char *x11_saved_data = NULL;
static u_int x11_saved_data_len = 0;
/*
* Fake X11 authentication data. This is what the server will be sending us;
* we should replace any occurrences of this by the real data.
*/
static u_char *x11_fake_data = NULL;
static u_int x11_fake_data_len;
/* -- agent forwarding */
#define NUM_SOCKS 10
/* AF_UNSPEC or AF_INET or AF_INET6 */
static int IPv4or6 = AF_UNSPEC;
/* helper */
static void port_open_helper(Channel *c, char *rtype);
/* non-blocking connect helpers */
static int connect_next(struct channel_connect *);
static void channel_connect_ctx_free(struct channel_connect *);
/* -- channel core */
Channel *
channel_by_id(int id)
{
Channel *c;
if (id < 0 || (u_int)id >= channels_alloc) {
logit("channel_by_id: %d: bad id", id);
return NULL;
}
c = channels[id];
if (c == NULL) {
logit("channel_by_id: %d: bad id: channel free", id);
return NULL;
}
return c;
}
/*
* Returns the channel if it is allowed to receive protocol messages.
* Private channels, like listening sockets, may not receive messages.
*/
Channel *
channel_lookup(int id)
{
Channel *c;
if ((c = channel_by_id(id)) == NULL)
return (NULL);
switch (c->type) {
case SSH_CHANNEL_X11_OPEN:
case SSH_CHANNEL_LARVAL:
case SSH_CHANNEL_CONNECTING:
case SSH_CHANNEL_DYNAMIC:
case SSH_CHANNEL_OPENING:
case SSH_CHANNEL_OPEN:
case SSH_CHANNEL_INPUT_DRAINING:
case SSH_CHANNEL_OUTPUT_DRAINING:
return (c);
}
logit("Non-public channel %d, type %d.", id, c->type);
return (NULL);
}
/*
* Register filedescriptors for a channel, used when allocating a channel or
* when the channel consumer/producer is ready, e.g. shell exec'd
*/
static void
channel_register_fds(Channel *c, int rfd, int wfd, int efd,
int extusage, int nonblock, int is_tty)
{
/* Update the maximum file descriptor value. */
channel_max_fd = MAX(channel_max_fd, rfd);
channel_max_fd = MAX(channel_max_fd, wfd);
channel_max_fd = MAX(channel_max_fd, efd);
if (rfd != -1)
fcntl(rfd, F_SETFD, FD_CLOEXEC);
if (wfd != -1 && wfd != rfd)
fcntl(wfd, F_SETFD, FD_CLOEXEC);
if (efd != -1 && efd != rfd && efd != wfd)
fcntl(efd, F_SETFD, FD_CLOEXEC);
c->rfd = rfd;
c->wfd = wfd;
c->sock = (rfd == wfd) ? rfd : -1;
c->efd = efd;
c->extended_usage = extusage;
if ((c->isatty = is_tty) != 0)
debug2("channel %d: rfd %d isatty", c->self, c->rfd);
/* enable nonblocking mode */
if (nonblock) {
if (rfd != -1)
set_nonblock(rfd);
if (wfd != -1)
set_nonblock(wfd);
if (efd != -1)
set_nonblock(efd);
}
}
/*
* Allocate a new channel object and set its type and socket. This will cause
* remote_name to be freed.
*/
Channel *
channel_new(char *ctype, int type, int rfd, int wfd, int efd,
u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
{
int found;
u_int i;
Channel *c;
/* Do initial allocation if this is the first call. */
if (channels_alloc == 0) {
channels_alloc = 10;
channels = xcalloc(channels_alloc, sizeof(Channel *));
for (i = 0; i < channels_alloc; i++)
channels[i] = NULL;
}
/* Try to find a free slot where to put the new channel. */
for (found = -1, i = 0; i < channels_alloc; i++)
if (channels[i] == NULL) {
/* Found a free slot. */
found = (int)i;
break;
}
if (found < 0) {
/* There are no free slots. Take last+1 slot and expand the array. */
found = channels_alloc;
if (channels_alloc > 10000)
fatal("channel_new: internal error: channels_alloc %d "
"too big.", channels_alloc);
channels = xrealloc(channels, channels_alloc + 10,
sizeof(Channel *));
channels_alloc += 10;
debug2("channel: expanding %d", channels_alloc);
for (i = found; i < channels_alloc; i++)
channels[i] = NULL;
}
/* Initialize and return new channel. */
c = channels[found] = xcalloc(1, sizeof(Channel));
buffer_init(&c->input);
buffer_init(&c->output);
buffer_init(&c->extended);
c->path = NULL;
c->ostate = CHAN_OUTPUT_OPEN;
c->istate = CHAN_INPUT_OPEN;
c->flags = 0;
channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0);
c->self = found;
c->type = type;
c->ctype = ctype;
c->local_window = window;
c->local_window_max = window;
c->local_consumed = 0;
c->local_maxpacket = maxpack;
c->remote_id = -1;
c->remote_name = xstrdup(remote_name);
c->remote_window = 0;
c->remote_maxpacket = 0;
c->force_drain = 0;
c->single_connection = 0;
c->detach_user = NULL;
c->detach_close = 0;
c->open_confirm = NULL;
c->open_confirm_ctx = NULL;
c->input_filter = NULL;
c->output_filter = NULL;
c->filter_ctx = NULL;
c->filter_cleanup = NULL;
c->ctl_chan = -1;
c->mux_rcb = NULL;
c->mux_ctx = NULL;
c->mux_pause = 0;
c->delayed = 1; /* prevent call to channel_post handler */
TAILQ_INIT(&c->status_confirms);
debug("channel %d: new [%s]", found, remote_name);
return c;
}
static int
channel_find_maxfd(void)
{
u_int i;
int max = 0;
Channel *c;
for (i = 0; i < channels_alloc; i++) {
c = channels[i];
if (c != NULL) {
max = MAX(max, c->rfd);
max = MAX(max, c->wfd);
max = MAX(max, c->efd);
}
}
return max;
}
int
channel_close_fd(int *fdp)
{
int ret = 0, fd = *fdp;
if (fd != -1) {
ret = close(fd);
*fdp = -1;
if (fd == channel_max_fd)
channel_max_fd = channel_find_maxfd();
}
return ret;
}
/* Close all channel fd/socket. */
static void
channel_close_fds(Channel *c)
{
debug3("channel %d: close_fds r %d w %d e %d",
c->self, c->rfd, c->wfd, c->efd);
channel_close_fd(&c->sock);
channel_close_fd(&c->rfd);
channel_close_fd(&c->wfd);
channel_close_fd(&c->efd);
}
/* Free the channel and close its fd/socket. */
void
channel_free(Channel *c)
{
char *s;
u_int i, n;
struct channel_confirm *cc;
for (n = 0, i = 0; i < channels_alloc; i++)
if (channels[i])
n++;
debug("channel %d: free: %s, nchannels %u", c->self,
c->remote_name ? c->remote_name : "???", n);
s = channel_open_message();
debug3("channel %d: status: %s", c->self, s);
xfree(s);
if (c->sock != -1)
shutdown(c->sock, SHUT_RDWR);
channel_close_fds(c);
buffer_free(&c->input);
buffer_free(&c->output);
buffer_free(&c->extended);
if (c->remote_name) {
xfree(c->remote_name);
c->remote_name = NULL;
}
if (c->path) {
xfree(c->path);
c->path = NULL;
}
while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
if (cc->abandon_cb != NULL)
cc->abandon_cb(c, cc->ctx);
TAILQ_REMOVE(&c->status_confirms, cc, entry);
bzero(cc, sizeof(*cc));
xfree(cc);
}
if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
c->filter_cleanup(c->self, c->filter_ctx);
channels[c->self] = NULL;
xfree(c);
}
void
channel_free_all(void)
{
u_int i;
for (i = 0; i < channels_alloc; i++)
if (channels[i] != NULL)
channel_free(channels[i]);
}
/*
* Closes the sockets/fds of all channels. This is used to close extra file
* descriptors after a fork.
*/
void
channel_close_all(void)
{
u_int i;
for (i = 0; i < channels_alloc; i++)
if (channels[i] != NULL)
channel_close_fds(channels[i]);
}
/*
* Stop listening to channels.
*/
void
channel_stop_listening(void)
{
u_int i;
Channel *c;
for (i = 0; i < channels_alloc; i++) {
c = channels[i];
if (c != NULL) {
switch (c->type) {
case SSH_CHANNEL_AUTH_SOCKET:
case SSH_CHANNEL_PORT_LISTENER:
case SSH_CHANNEL_RPORT_LISTENER:
case SSH_CHANNEL_X11_LISTENER:
channel_close_fd(&c->sock);
channel_free(c);
break;
}
}
}
}
/*
* 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(void)
{
u_int i;
Channel *c;
for (i = 0; i < channels_alloc; i++) {
c = channels[i];
if (c != NULL && c->type == SSH_CHANNEL_OPEN) {
#if 0
if (!compat20 &&
buffer_len(&c->input) > packet_get_maxsize()) {
debug2("channel %d: big input buffer %d",
c->self, buffer_len(&c->input));
return 0;
}
#endif
if (buffer_len(&c->output) > packet_get_maxsize()) {
debug2("channel %d: big output buffer %u > %u",
c->self, buffer_len(&c->output),
packet_get_maxsize());
return 0;
}
}
}
return 1;
}
/* Returns true if any channel is still open. */
int
channel_still_open(void)
{
u_int i;
Channel *c;
for (i = 0; i < channels_alloc; i++) {
c = channels[i];
if (c == NULL)
continue;
switch (c->type) {
case SSH_CHANNEL_X11_LISTENER:
case SSH_CHANNEL_PORT_LISTENER:
case SSH_CHANNEL_RPORT_LISTENER:
case SSH_CHANNEL_MUX_LISTENER:
case SSH_CHANNEL_CLOSED:
case SSH_CHANNEL_AUTH_SOCKET:
case SSH_CHANNEL_DYNAMIC:
case SSH_CHANNEL_CONNECTING:
case SSH_CHANNEL_ZOMBIE:
continue;
case SSH_CHANNEL_LARVAL:
if (!compat20)
fatal("cannot happen: SSH_CHANNEL_LARVAL");
continue;
case SSH_CHANNEL_OPENING:
case SSH_CHANNEL_OPEN:
case SSH_CHANNEL_X11_OPEN:
case SSH_CHANNEL_MUX_CLIENT:
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", c->type);
/* NOTREACHED */
}
}
return 0;
}
/* Returns the id of an open channel suitable for keepaliving */
int
channel_find_open(void)
{
u_int i;
Channel *c;
for (i = 0; i < channels_alloc; i++) {
c = channels[i];
if (c == NULL || c->remote_id < 0)
continue;
switch (c->type) {
case SSH_CHANNEL_CLOSED:
case SSH_CHANNEL_DYNAMIC:
case SSH_CHANNEL_X11_LISTENER:
case SSH_CHANNEL_PORT_LISTENER:
case SSH_CHANNEL_RPORT_LISTENER:
case SSH_CHANNEL_MUX_LISTENER:
case SSH_CHANNEL_MUX_CLIENT:
case SSH_CHANNEL_OPENING:
case SSH_CHANNEL_CONNECTING:
case SSH_CHANNEL_ZOMBIE:
continue;
case SSH_CHANNEL_LARVAL:
case SSH_CHANNEL_AUTH_SOCKET:
case SSH_CHANNEL_OPEN:
case SSH_CHANNEL_X11_OPEN:
return i;
case SSH_CHANNEL_INPUT_DRAINING:
case SSH_CHANNEL_OUTPUT_DRAINING:
if (!compat13)
fatal("cannot happen: OUT_DRAIN");
return i;
default:
fatal("channel_find_open: bad channel type %d", c->type);
/* NOTREACHED */
}
}
return -1;
}
/*
* 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(void)
{
Buffer buffer;
Channel *c;
char buf[1024], *cp;
u_int i;
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)
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:
case SSH_CHANNEL_MUX_CLIENT:
case SSH_CHANNEL_MUX_LISTENER:
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 cc %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, c->ctl_chan);
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;
}
debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
packet_start(SSH2_MSG_CHANNEL_REQUEST);
packet_put_int(c->remote_id);
packet_put_cstring(service);
packet_put_char(wantconfirm);
}
void
channel_register_status_confirm(int id, channel_confirm_cb *cb,
channel_confirm_abandon_cb *abandon_cb, void *ctx)
{
struct channel_confirm *cc;
Channel *c;
if ((c = channel_lookup(id)) == NULL)
fatal("channel_register_expect: %d: bad id", id);
cc = xmalloc(sizeof(*cc));
cc->cb = cb;
cc->abandon_cb = abandon_cb;
cc->ctx = ctx;
TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry);
}
void
channel_register_open_confirm(int id, channel_open_fn *fn, void *ctx)
{
Channel *c = channel_lookup(id);
if (c == NULL) {
logit("channel_register_open_confirm: %d: bad id", id);
return;
}
c->open_confirm = fn;
c->open_confirm_ctx = ctx;
}
void
channel_register_cleanup(int id, channel_callback_fn *fn, int do_close)
{
Channel *c = channel_by_id(id);
if (c == NULL) {
logit("channel_register_cleanup: %d: bad id", id);
return;
}
c->detach_user = fn;
c->detach_close = do_close;
}
void
channel_cancel_cleanup(int id)
{
Channel *c = channel_by_id(id);
if (c == NULL) {
logit("channel_cancel_cleanup: %d: bad id", id);
return;
}
c->detach_user = NULL;
c->detach_close = 0;
}
void
channel_register_filter(int id, channel_infilter_fn *ifn,
channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx)
{
Channel *c = channel_lookup(id);
if (c == NULL) {
logit("channel_register_filter: %d: bad id", id);
return;
}
c->input_filter = ifn;
c->output_filter = ofn;
c->filter_ctx = ctx;
c->filter_cleanup = cfn;
}
void
channel_set_fds(int id, int rfd, int wfd, int efd,
int extusage, int nonblock, int is_tty, 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, is_tty);
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];
/* ARGSUSED */
static void
channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset)
{
FD_SET(c->sock, readset);
}
/* ARGSUSED */
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 &&
buffer_check_alloc(&c->input, CHAN_RBUF))
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 &&
!(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) {
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);
}
/* XXX: What about efd? races? */
}
/* ARGSUSED */
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;
debug2("channel %d: closing after input drain.", c->self);
}
}
/* ARGSUSED */
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 {
debug2("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) {
debug2("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) {
debug2("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.");
debug2("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;
debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
}
}
static void
channel_pre_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
{
if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause &&
buffer_check_alloc(&c->input, CHAN_RBUF))
FD_SET(c->rfd, readset);
if (c->istate == CHAN_INPUT_WAIT_DRAIN) {
/* clear buffer immediately (discard any partial packet) */
buffer_clear(&c->input);
chan_ibuf_empty(c);
/* Start output drain. XXX just kill chan? */
chan_rcvd_oclose(c);
}
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)
chan_obuf_empty(c);
}
}
/* try to decode a socks4 header */
/* ARGSUSED */
static int
channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset)
{
char *p, *host;
u_int len, have, i, found, need;
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);
need = 1;
/* SOCKS4A uses an invalid IP address 0.0.0.x */
if (p[4] == 0 && p[5] == 0 && p[6] == 0 && p[7] != 0) {
debug2("channel %d: socks4a request", c->self);
/* ... and needs an extra string (the hostname) */
need = 2;
}
/* Check for terminating NUL on the string(s) */
for (found = 0, i = len; i < have; i++) {
if (p[i] == '\0') {
found++;
if (found == need)
break;
}
if (i > 1024) {
/* the peer is probably sending garbage */
debug("channel %d: decode socks4: too long",
c->self);
return -1;
}
}
if (found < need)
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);
len++; /* trailing '\0' */
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);
if (c->path != NULL) {
xfree(c->path);
c->path = NULL;
}
if (need == 1) { /* SOCKS4: one string */
host = inet_ntoa(s4_req.dest_addr);
c->path = xstrdup(host);
} else { /* SOCKS4A: two strings */
have = buffer_len(&c->input);
p = buffer_ptr(&c->input);
len = strlen(p);
debug2("channel %d: decode socks4a: host %s/%d",
c->self, p, len);
len++; /* trailing '\0' */
if (len > have)
fatal("channel %d: decode socks4a: len %d > have %d",
c->self, len, have);
if (len > NI_MAXHOST) {
error("channel %d: hostname \"%.100s\" too long",
c->self, p);
return -1;
}
c->path = xstrdup(p);
buffer_consume(&c->input, len);
}
c->host_port = ntohs(s4_req.dest_port);
debug2("channel %d: dynamic request: socks4 host %s port %u command %u",
c->self, c->path, c->host_port, s4_req.command);
if (s4_req.command != 1) {
debug("channel %d: cannot handle: %s cn %d",
c->self, need == 1 ? "SOCKS4" : "SOCKS4A", 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, &s4_rsp, sizeof(s4_rsp));
return 1;
}
/* try to decode a socks5 header */
#define SSH_SOCKS5_AUTHDONE 0x1000
#define SSH_SOCKS5_NOAUTH 0x00
#define SSH_SOCKS5_IPV4 0x01
#define SSH_SOCKS5_DOMAIN 0x03
#define SSH_SOCKS5_IPV6 0x04
#define SSH_SOCKS5_CONNECT 0x01
#define SSH_SOCKS5_SUCCESS 0x00
/* ARGSUSED */
static int
channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset)
{
struct {
u_int8_t version;
u_int8_t command;
u_int8_t reserved;
u_int8_t atyp;
} s5_req, s5_rsp;
u_int16_t dest_port;
u_char *p, dest_addr[255+1], ntop[INET6_ADDRSTRLEN];
u_int have, need, i, found, nmethods, addrlen, af;
debug2("channel %d: decode socks5", c->self);
p = buffer_ptr(&c->input);
if (p[0] != 0x05)
return -1;
have = buffer_len(&c->input);
if (!(c->flags & SSH_SOCKS5_AUTHDONE)) {
/* format: ver | nmethods | methods */
if (have < 2)
return 0;
nmethods = p[1];
if (have < nmethods + 2)
return 0;
/* look for method: "NO AUTHENTICATION REQUIRED" */
for (found = 0, i = 2; i < nmethods + 2; i++) {
if (p[i] == SSH_SOCKS5_NOAUTH) {
found = 1;
break;
}
}
if (!found) {
debug("channel %d: method SSH_SOCKS5_NOAUTH not found",
c->self);
return -1;
}
buffer_consume(&c->input, nmethods + 2);
buffer_put_char(&c->output, 0x05); /* version */
buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */
FD_SET(c->sock, writeset);
c->flags |= SSH_SOCKS5_AUTHDONE;
debug2("channel %d: socks5 auth done", c->self);
return 0; /* need more */
}
debug2("channel %d: socks5 post auth", c->self);
if (have < sizeof(s5_req)+1)
return 0; /* need more */
memcpy(&s5_req, p, sizeof(s5_req));
if (s5_req.version != 0x05 ||
s5_req.command != SSH_SOCKS5_CONNECT ||
s5_req.reserved != 0x00) {
debug2("channel %d: only socks5 connect supported", c->self);
return -1;
}
switch (s5_req.atyp){
case SSH_SOCKS5_IPV4:
addrlen = 4;
af = AF_INET;
break;
case SSH_SOCKS5_DOMAIN:
addrlen = p[sizeof(s5_req)];
af = -1;
break;
case SSH_SOCKS5_IPV6:
addrlen = 16;
af = AF_INET6;
break;
default:
debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp);
return -1;
}
need = sizeof(s5_req) + addrlen + 2;
if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
need++;
if (have < need)
return 0;
buffer_consume(&c->input, sizeof(s5_req));
if (s5_req.atyp == SSH_SOCKS5_DOMAIN)
buffer_consume(&c->input, 1); /* host string length */
buffer_get(&c->input, (char *)&dest_addr, addrlen);
buffer_get(&c->input, (char *)&dest_port, 2);
dest_addr[addrlen] = '\0';
if (c->path != NULL) {
xfree(c->path);
c->path = NULL;
}
if (s5_req.atyp == SSH_SOCKS5_DOMAIN) {
if (addrlen >= NI_MAXHOST) {
error("channel %d: dynamic request: socks5 hostname "
"\"%.100s\" too long", c->self, dest_addr);
return -1;
}
c->path = xstrdup(dest_addr);
} else {
if (inet_ntop(af, dest_addr, ntop, sizeof(ntop)) == NULL)
return -1;
c->path = xstrdup(ntop);
}
c->host_port = ntohs(dest_port);
debug2("channel %d: dynamic request: socks5 host %s port %u command %u",
c->self, c->path, c->host_port, s5_req.command);
s5_rsp.version = 0x05;
s5_rsp.command = SSH_SOCKS5_SUCCESS;
s5_rsp.reserved = 0; /* ignored */
s5_rsp.atyp = SSH_SOCKS5_IPV4;
((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY;
dest_port = 0; /* ignored */
buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp));
buffer_append(&c->output, &dest_addr, sizeof(struct in_addr));
buffer_append(&c->output, &dest_port, sizeof(dest_port));
return 1;
}
Channel *
channel_connect_stdio_fwd(const char *host_to_connect, u_short port_to_connect,
int in, int out)
{
Channel *c;
debug("channel_connect_stdio_fwd %s:%d", host_to_connect,
port_to_connect);
c = channel_new("stdio-forward", SSH_CHANNEL_OPENING, in, out,
-1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
0, "stdio-forward", /*nonblock*/0);
c->path = xstrdup(host_to_connect);
c->host_port = port_to_connect;
c->listening_port = 0;
c->force_drain = 1;
channel_register_fds(c, in, out, -1, 0, 1, 0);
port_open_helper(c, "direct-tcpip");
return c;
}
/* dynamic port forwarding */
static void
channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset)
{
u_char *p;
u_int have;
int ret;
have = buffer_len(&c->input);
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 < 3) {
/* 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;
case 0x05:
ret = channel_decode_socks5(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. */
/* ARGSUSED */
static void
channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset)
{
Channel *nc;
struct sockaddr_storage 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, (struct sockaddr *)&addr, &addrlen);
if (c->single_connection) {
debug2("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) {
debug2("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);
int remote_port = get_peer_port(c->sock);
if (remote_port == -1) {
/* Fake addr/port to appease peers that validate it (Tectia) */
xfree(remote_ipaddr);
remote_ipaddr = xstrdup("127.0.0.1");
remote_port = 65535;
}
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((u_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);
}
static void
channel_set_reuseaddr(int fd)
{
int on = 1;
/*
* Set socket options.
* Allow local port reuse in TIME_WAIT.
*/
if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno));
}
/*
* This socket is listening for connections to a forwarded TCP/IP port.
*/
/* ARGSUSED */
static void
channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset)
{
Channel *nc;
struct sockaddr_storage 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, (struct sockaddr *)&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;
if (c->path != NULL)
nc->path = xstrdup(c->path);
if (nextstate != SSH_CHANNEL_DYNAMIC)
port_open_helper(nc, rtype);
}
}
/*
* This is the authentication agent socket listening for connections from
* clients.
*/
/* ARGSUSED */
static void
channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset)
{
Channel *nc;
int newsock;
struct sockaddr_storage addr;
socklen_t addrlen;
if (FD_ISSET(c->sock, readset)) {
addrlen = sizeof(addr);
newsock = accept(c->sock, (struct sockaddr *)&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();
}
}
/* ARGSUSED */
static void
channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset)
{
int err = 0, sock;
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 to %s port %d",
c->self, c->connect_ctx.host, c->connect_ctx.port);
channel_connect_ctx_free(&c->connect_ctx);
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: connection failed: %s",
c->self, strerror(err));
/* Try next address, if any */
if ((sock = connect_next(&c->connect_ctx)) > 0) {
close(c->sock);
c->sock = c->rfd = c->wfd = sock;
channel_max_fd = channel_find_maxfd();
return;
}
/* Exhausted all addresses */
error("connect_to %.100s port %d: failed.",
c->connect_ctx.host, c->connect_ctx.port);
channel_connect_ctx_free(&c->connect_ctx);
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();
}
}
/* ARGSUSED */
static int
channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset)
{
char buf[CHAN_RBUF];
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) {
debug2("channel %d: read<=0 rfd %d len %d",
c->self, c->rfd, len);
if (c->type != SSH_CHANNEL_OPEN) {
debug2("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;
debug2("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) {
debug2("channel %d: filter stops", c->self);
chan_read_failed(c);
}
} else if (c->datagram) {
buffer_put_string(&c->input, buf, len);
} else {
buffer_append(&c->input, buf, len);
}
}
return 1;
}
/* ARGSUSED */
static int
channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset)
{
struct termios tio;
u_char *data = NULL, *buf;
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) {
if (c->output_filter != NULL) {
if ((buf = c->output_filter(c, &data, &dlen)) == NULL) {
debug2("channel %d: filter stops", c->self);
if (c->type != SSH_CHANNEL_OPEN)
chan_mark_dead(c);
else
chan_write_failed(c);
return -1;
}
} else if (c->datagram) {
buf = data = buffer_get_string(&c->output, &dlen);
} else {
buf = data = buffer_ptr(&c->output);
dlen = buffer_len(&c->output);
}
if (c->datagram) {
/* ignore truncated writes, datagrams might get lost */
c->local_consumed += dlen + 4;
len = write(c->wfd, buf, dlen);
xfree(data);
if (len < 0 && (errno == EINTR || errno == EAGAIN))
return 1;
if (len <= 0) {
if (c->type != SSH_CHANNEL_OPEN)
chan_mark_dead(c);
else
chan_write_failed(c);
return -1;
}
return 1;
}
len = write(c->wfd, buf, dlen);
if (len < 0 && (errno == EINTR || errno == EAGAIN))
return 1;
if (len <= 0) {
if (c->type != SSH_CHANNEL_OPEN) {
debug2("channel %d: not open", c->self);
chan_mark_dead(c);
return -1;
} else if (compat13) {
buffer_clear(&c->output);
debug2("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 && buf[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 + buf)
*/
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[CHAN_RBUF];
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;
}
/* ARGSUSED */
static int
channel_check_window(Channel *c)
{
if (c->type == SSH_CHANNEL_OPEN &&
!(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) &&
((c->local_window_max - c->local_window >
c->local_maxpacket*3) ||
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)
{
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 u_int
read_mux(Channel *c, u_int need)
{
char buf[CHAN_RBUF];
int len;
u_int rlen;
if (buffer_len(&c->input) < need) {
rlen = need - buffer_len(&c->input);
len = read(c->rfd, buf, MIN(rlen, CHAN_RBUF));
if (len <= 0) {
if (errno != EINTR && errno != EAGAIN) {
debug2("channel %d: ctl read<=0 rfd %d len %d",
c->self, c->rfd, len);
chan_read_failed(c);
return 0;
}
} else
buffer_append(&c->input, buf, len);
}
return buffer_len(&c->input);
}
static void
channel_post_mux_client(Channel *c, fd_set *readset, fd_set *writeset)
{
u_int need;
ssize_t len;
if (!compat20)
fatal("%s: entered with !compat20", __func__);
if (c->rfd != -1 && !c->mux_pause && FD_ISSET(c->rfd, readset) &&
(c->istate == CHAN_INPUT_OPEN ||
c->istate == CHAN_INPUT_WAIT_DRAIN)) {
/*
* Don't not read past the precise end of packets to
* avoid disrupting fd passing.
*/
if (read_mux(c, 4) < 4) /* read header */
return;
need = get_u32(buffer_ptr(&c->input));
#define CHANNEL_MUX_MAX_PACKET (256 * 1024)
if (need > CHANNEL_MUX_MAX_PACKET) {
debug2("channel %d: packet too big %u > %u",
c->self, CHANNEL_MUX_MAX_PACKET, need);
chan_rcvd_oclose(c);
return;
}
if (read_mux(c, need + 4) < need + 4) /* read body */
return;
if (c->mux_rcb(c) != 0) {
debug("channel %d: mux_rcb failed", c->self);
chan_mark_dead(c);
return;
}
}
if (c->wfd != -1 && FD_ISSET(c->wfd, writeset) &&
buffer_len(&c->output) > 0) {
len = write(c->wfd, buffer_ptr(&c->output),
buffer_len(&c->output));
if (len < 0 && (errno == EINTR || errno == EAGAIN))
return;
if (len <= 0) {
chan_mark_dead(c);
return;
}
buffer_consume(&c->output, len);
}
}
static void
channel_post_mux_listener(Channel *c, fd_set *readset, fd_set *writeset)
{
Channel *nc;
struct sockaddr_storage addr;
socklen_t addrlen;
int newsock;
uid_t euid;
gid_t egid;
if (!FD_ISSET(c->sock, readset))
return;
debug("multiplexing control connection");
/*
* Accept connection on control socket
*/
memset(&addr, 0, sizeof(addr));
addrlen = sizeof(addr);
if ((newsock = accept(c->sock, (struct sockaddr*)&addr,
&addrlen)) == -1) {
error("%s accept: %s", __func__, strerror(errno));
return;
}
if (getpeereid(newsock, &euid, &egid) < 0) {
error("%s getpeereid failed: %s", __func__,
strerror(errno));
close(newsock);
return;
}
if ((euid != 0) && (getuid() != euid)) {
error("multiplex uid mismatch: peer euid %u != uid %u",
(u_int)euid, (u_int)getuid());
close(newsock);
return;
}
nc = channel_new("multiplex client", SSH_CHANNEL_MUX_CLIENT,
newsock, newsock, -1, c->local_window_max,
c->local_maxpacket, 0, "mux-control", 1);
nc->mux_rcb = c->mux_rcb;
debug3("%s: new mux channel %d fd %d", __func__,
nc->self, nc->sock);
/* establish state */
nc->mux_rcb(nc);
/* mux state transitions must not elicit protocol messages */
nc->flags |= CHAN_LOCAL;
}
/* ARGSUSED */
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_pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener;
channel_pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client;
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;
channel_post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener;
channel_post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client;
}
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, c->detach_close))
return;
debug2("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;
debug2("channel %d: gc: user detached", c->self);
}
if (!chan_is_dead(c, 1))
return;
debug2("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;
u_int i, oalloc;
Channel *c;
if (!did_init) {
channel_handler_init();
did_init = 1;
}
for (i = 0, oalloc = channels_alloc; i < oalloc; i++) {
c = channels[i];
if (c == NULL)
continue;
if (c->delayed) {
if (ftab == channel_pre)
c->delayed = 0;
else
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,
u_int *nallocp, int rekeying)
{
u_int n, sz, nfdset;
n = MAX(*maxfdp, channel_max_fd);
nfdset = howmany(n+1, NFDBITS);
/* Explicitly test here, because xrealloc isn't always called */
if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask))
fatal("channel_prepare_select: max_fd (%d) is too large", n);
sz = nfdset * sizeof(fd_mask);
/* perhaps check sz < nalloc/2 and shrink? */
if (*readsetp == NULL || sz > *nallocp) {
*readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask));
*writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask));
*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;
u_int i, 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) {
if (c->datagram) {
if (len > 0) {
u_char *data;
u_int dlen;
data = buffer_get_string(&c->input,
&dlen);
packet_start(SSH2_MSG_CHANNEL_DATA);
packet_put_int(c->remote_id);
packet_put_string(data, dlen);
packet_send();
c->remote_window -= dlen + 4;
xfree(data);
}
continue;
}
/*
* 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 */
/* ARGSUSED */
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;
/* Get the data. */
data = packet_get_string_ptr(&data_len);
/*
* Ignore data for protocol > 1.3 if output end is no longer open.
* For protocol 2 the sending side is reducing its window as it sends
* data, so we must 'fake' consumption of the data in order to ensure
* that window updates are sent back. Otherwise the connection might
* deadlock.
*/
if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) {
if (compat20) {
c->local_window -= data_len;
c->local_consumed += data_len;
}
return;
}
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);
return;
}
c->local_window -= data_len;
}
if (c->datagram)
buffer_put_string(&c->output, data, data_len);
else
buffer_append(&c->output, data, data_len);
packet_check_eom();
}
/* ARGSUSED */
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);
}
/* ARGSUSED */
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);
}
}
/* ARGSUSED */
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 */
/* ARGSUSED */
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);
}
/* ARGSUSED */
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);
}
/* ARGSUSED */
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->open_confirm) {
debug2("callback start");
c->open_confirm(c->self, 1, c->open_confirm_ctx);
debug2("callback done");
}
debug2("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";
}
/* ARGSUSED */
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);
if (c->open_confirm) {
debug2("callback start");
c->open_confirm(c->self, 0, c->open_confirm_ctx);
debug2("callback done");
}
}
packet_check_eom();
/* Schedule the channel for cleanup/deletion. */
chan_mark_dead(c);
}
/* ARGSUSED */
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) {
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;
}
/* ARGSUSED */
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;
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();
c = channel_connect_to(host, host_port,
"connected socket", originator_string);
xfree(originator_string);
xfree(host);
if (c == NULL) {
packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
packet_put_int(remote_id);
packet_send();
} else
c->remote_id = remote_id;
}
/* ARGSUSED */
void
channel_input_status_confirm(int type, u_int32_t seq, void *ctxt)
{
Channel *c;
struct channel_confirm *cc;
int id;
/* Reset keepalive timeout */
packet_set_alive_timeouts(0);
id = packet_get_int();
packet_check_eom();
debug2("channel_input_status_confirm: type %d id %d", type, id);
if ((c = channel_lookup(id)) == NULL) {
logit("channel_input_status_confirm: %d: unknown", id);
return;
}
;
if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL)
return;
cc->cb(type, c, cc->ctx);
TAILQ_REMOVE(&c->status_confirms, cc, entry);
bzero(cc, sizeof(*cc));
xfree(cc);
}
/* -- 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, int *allocated_listen_port,
const char *host_to_connect, u_short port_to_connect, int gateway_ports)
{
Channel *c;
int sock, r, success = 0, wildcard = 0, is_client;
struct addrinfo hints, *ai, *aitop;
const char *host, *addr;
char ntop[NI_MAXHOST], strport[NI_MAXSERV];
in_port_t *lport_p;
host = (type == SSH_CHANNEL_RPORT_LISTENER) ?
listen_addr : host_to_connect;
is_client = (type == SSH_CHANNEL_PORT_LISTENER);
if (host == NULL) {
error("No forward host name.");
return 0;
}
if (strlen(host) >= NI_MAXHOST) {
error("Forward host name too long.");
return 0;
}
/*
* Determine whether or not a port forward listens to loopback,
* specified address or wildcard. On the client, a specified bind
* address will always override gateway_ports. On the server, a
* gateway_ports of 1 (``yes'') will override the client's
* specification and force a wildcard bind, whereas a value of 2
* (``clientspecified'') will bind to whatever address the client
* asked for.
*
* Special-case listen_addrs are:
*
* "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR
* "" (empty string), "*" -> wildcard v4/v6
* "localhost" -> loopback v4/v6
*/
addr = NULL;
if (listen_addr == NULL) {
/* No address specified: default to gateway_ports setting */
if (gateway_ports)
wildcard = 1;
} else if (gateway_ports || is_client) {
if (((datafellows & SSH_OLD_FORWARD_ADDR) &&
strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) ||
*listen_addr == '\0' || strcmp(listen_addr, "*") == 0 ||
(!is_client && gateway_ports == 1))
wildcard = 1;
else if (strcmp(listen_addr, "localhost") != 0)
addr = listen_addr;
}
debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s",
type, wildcard, (addr == NULL) ? "NULL" : addr);
/*
* 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 = wildcard ? AI_PASSIVE : 0;
hints.ai_socktype = SOCK_STREAM;
snprintf(strport, sizeof strport, "%d", listen_port);
if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) {
if (addr == NULL) {
/* This really shouldn't happen */
packet_disconnect("getaddrinfo: fatal error: %s",
ssh_gai_strerror(r));
} else {
error("channel_setup_fwd_listener: "
"getaddrinfo(%.64s): %s", addr,
ssh_gai_strerror(r));
}
return 0;
}
if (allocated_listen_port != NULL)
*allocated_listen_port = 0;
for (ai = aitop; ai; ai = ai->ai_next) {
switch (ai->ai_family) {
case AF_INET:
lport_p = &((struct sockaddr_in *)ai->ai_addr)->
sin_port;
break;
case AF_INET6:
lport_p = &((struct sockaddr_in6 *)ai->ai_addr)->
sin6_port;
break;
default:
continue;
}
/*
* If allocating a port for -R forwards, then use the
* same port for all address families.
*/
if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
allocated_listen_port != NULL && *allocated_listen_port > 0)
*lport_p = htons(*allocated_listen_port);
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;
}
channel_set_reuseaddr(sock);
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, SSH_LISTEN_BACKLOG) < 0) {
error("listen: %.100s", strerror(errno));
close(sock);
continue;
}
/*
* listen_port == 0 requests a dynamically allocated port -
* record what we got.
*/
if (type == SSH_CHANNEL_RPORT_LISTENER && listen_port == 0 &&
allocated_listen_port != NULL &&
*allocated_listen_port == 0) {
*allocated_listen_port = get_sock_port(sock, 1);
debug("Allocated listen port %d",
*allocated_listen_port);
}
/* 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);
c->path = xstrdup(host);
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;
}
int
channel_cancel_rport_listener(const char *host, u_short port)
{
u_int i;
int found = 0;
for (i = 0; i < channels_alloc; i++) {
Channel *c = channels[i];
if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER &&
strcmp(c->path, host) == 0 && c->listening_port == port) {
debug2("%s: close channel %d", __func__, i);
channel_free(c);
found = 1;
}
}
return (found);
}
/* protocol local port fwd, used by ssh (and sshd in v1) */
int
channel_setup_local_fwd_listener(const char *listen_host, 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,
listen_host, listen_port, NULL, 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 *allocated_listen_port, int gateway_ports)
{
return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER,
listen_address, listen_port, allocated_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.
*/
int
channel_request_remote_forwarding(const char *listen_host, 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;
if (listen_host == NULL) {
if (datafellows & SSH_BUG_RFWD_ADDR)
address_to_bind = "127.0.0.1";
else
address_to_bind = "localhost";
} else if (*listen_host == '\0' ||
strcmp(listen_host, "*") == 0) {
if (datafellows & SSH_BUG_RFWD_ADDR)
address_to_bind = "0.0.0.0";
else
address_to_bind = "";
} else
address_to_bind = listen_host;
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:
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++;
}
return (success ? 0 : -1);
}
/*
* Request cancellation of remote forwarding of connection host:port from
* local side.
*/
void
channel_request_rforward_cancel(const char *host, u_short port)
{
int i;
if (!compat20)
return;
for (i = 0; i < num_permitted_opens; i++) {
if (permitted_opens[i].host_to_connect != NULL &&
permitted_opens[i].listen_port == port)
break;
}
if (i >= num_permitted_opens) {
debug("%s: requested forward not found", __func__);
return;
}
packet_start(SSH2_MSG_GLOBAL_REQUEST);
packet_put_cstring("cancel-tcpip-forward");
packet_put_char(0);
packet_put_cstring(host == NULL ? "" : host);
packet_put_int(port);
packet_send();
permitted_opens[i].listen_port = 0;
permitted_opens[i].port_to_connect = 0;
xfree(permitted_opens[i].host_to_connect);
permitted_opens[i].host_to_connect = NULL;
}
/*
* 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).
*/
int
channel_input_port_forward_request(int is_root, int gateway_ports)
{
u_short port, host_port;
int success = 0;
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);
if (host_port == 0)
packet_disconnect("Dynamic forwarding denied.");
/* Initiate forwarding */
success = channel_setup_local_fwd_listener(NULL, port, hostname,
host_port, gateway_ports);
/* Free the argument string. */
xfree(hostname);
return (success ? 0 : -1);
}
/*
* 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_add_permitted_opens: 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;
}
int
channel_add_adm_permitted_opens(char *host, int port)
{
if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION)
fatal("channel_add_adm_permitted_opens: too many forwards");
debug("config allows port forwarding to host %s port %d", host, port);
permitted_adm_opens[num_adm_permitted_opens].host_to_connect
= xstrdup(host);
permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port;
return ++num_adm_permitted_opens;
}
void
channel_clear_permitted_opens(void)
{
int i;
for (i = 0; i < num_permitted_opens; i++)
if (permitted_opens[i].host_to_connect != NULL)
xfree(permitted_opens[i].host_to_connect);
num_permitted_opens = 0;
}
void
channel_clear_adm_permitted_opens(void)
{
int i;
for (i = 0; i < num_adm_permitted_opens; i++)
if (permitted_adm_opens[i].host_to_connect != NULL)
xfree(permitted_adm_opens[i].host_to_connect);
num_adm_permitted_opens = 0;
}
void
channel_print_adm_permitted_opens(void)
{
int i;
printf("permitopen");
if (num_adm_permitted_opens == 0) {
printf(" any\n");
return;
}
for (i = 0; i < num_adm_permitted_opens; i++)
if (permitted_adm_opens[i].host_to_connect != NULL)
printf(" %s:%d", permitted_adm_opens[i].host_to_connect,
permitted_adm_opens[i].port_to_connect);
printf("\n");
}
/* Try to start non-blocking connect to next host in cctx list */
static int
connect_next(struct channel_connect *cctx)
{
int sock, saved_errno;
char ntop[NI_MAXHOST], strport[NI_MAXSERV];
for (; cctx->ai; cctx->ai = cctx->ai->ai_next) {
if (cctx->ai->ai_family != AF_INET &&
cctx->ai->ai_family != AF_INET6)
continue;
if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen,
ntop, sizeof(ntop), strport, sizeof(strport),
NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
error("connect_next: getnameinfo failed");
continue;
}
if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype,
cctx->ai->ai_protocol)) == -1) {
if (cctx->ai->ai_next == NULL)
error("socket: %.100s", strerror(errno));
else
verbose("socket: %.100s", strerror(errno));
continue;
}
if (set_nonblock(sock) == -1)
fatal("%s: set_nonblock(%d)", __func__, sock);
if (connect(sock, cctx->ai->ai_addr,
cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) {
debug("connect_next: host %.100s ([%.100s]:%s): "
"%.100s", cctx->host, ntop, strport,
strerror(errno));
saved_errno = errno;
close(sock);
errno = saved_errno;
continue; /* fail -- try next */
}
debug("connect_next: host %.100s ([%.100s]:%s) "
"in progress, fd=%d", cctx->host, ntop, strport, sock);
cctx->ai = cctx->ai->ai_next;
set_nodelay(sock);
return sock;
}
return -1;
}
static void
channel_connect_ctx_free(struct channel_connect *cctx)
{
xfree(cctx->host);
if (cctx->aitop)
freeaddrinfo(cctx->aitop);
bzero(cctx, sizeof(*cctx));
cctx->host = NULL;
cctx->ai = cctx->aitop = NULL;
}
/* Return CONNECTING channel to remote host, port */
static Channel *
connect_to(const char *host, u_short port, char *ctype, char *rname)
{
struct addrinfo hints;
int gaierr;
int sock = -1;
char strport[NI_MAXSERV];
struct channel_connect cctx;
Channel *c;
memset(&cctx, 0, sizeof(cctx));
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, &cctx.aitop)) != 0) {
error("connect_to %.100s: unknown host (%s)", host,
ssh_gai_strerror(gaierr));
return NULL;
}
cctx.host = xstrdup(host);
cctx.port = port;
cctx.ai = cctx.aitop;
if ((sock = connect_next(&cctx)) == -1) {
error("connect to %.100s port %d failed: %s",
host, port, strerror(errno));
channel_connect_ctx_free(&cctx);
return NULL;
}
c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1,
CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1);
c->connect_ctx = cctx;
return c;
}
Channel *
channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname)
{
int i;
for (i = 0; i < num_permitted_opens; i++) {
if (permitted_opens[i].host_to_connect != NULL &&
permitted_opens[i].listen_port == listen_port) {
return connect_to(
permitted_opens[i].host_to_connect,
permitted_opens[i].port_to_connect, ctype, rname);
}
}
error("WARNING: Server requests forwarding for unknown listen_port %d",
listen_port);
return NULL;
}
/* Check if connecting to that port is permitted and connect. */
Channel *
channel_connect_to(const char *host, u_short port, char *ctype, char *rname)
{
int i, permit, permit_adm = 1;
permit = all_opens_permitted;
if (!permit) {
for (i = 0; i < num_permitted_opens; i++)
if (permitted_opens[i].host_to_connect != NULL &&
permitted_opens[i].port_to_connect == port &&
strcmp(permitted_opens[i].host_to_connect, host) == 0)
permit = 1;
}
if (num_adm_permitted_opens > 0) {
permit_adm = 0;
for (i = 0; i < num_adm_permitted_opens; i++)
if (permitted_adm_opens[i].host_to_connect != NULL &&
permitted_adm_opens[i].port_to_connect == port &&
strcmp(permitted_adm_opens[i].host_to_connect, host)
== 0)
permit_adm = 1;
}
if (!permit || !permit_adm) {
logit("Received request to connect to host %.100s port %d, "
"but the request was denied.", host, port);
return NULL;
}
return connect_to(host, port, ctype, rname);
}
void
channel_send_window_changes(void)
{
u_int i;
struct winsize ws;
for (i = 0; i < channels_alloc; i++) {
if (channels[i] == NULL || !channels[i]->client_tty ||
channels[i]->type != SSH_CHANNEL_OPEN)
continue;
if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0)
continue;
channel_request_start(i, "window-change", 0);
packet_put_int((u_int)ws.ws_col);
packet_put_int((u_int)ws.ws_row);
packet_put_int((u_int)ws.ws_xpixel);
packet_put_int((u_int)ws.ws_ypixel);
packet_send();
}
}
/* -- 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, int **chanids)
{
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];
if (chanids == NULL)
return -1;
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", ssh_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) {
error("socket: %.100s", strerror(errno));
freeaddrinfo(aitop);
return -1;
}
channel_set_reuseaddr(sock);
if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
debug2("bind port %d: %.100s", port, strerror(errno));
close(sock);
for (n = 0; n < num_socks; n++) {
close(socks[n]);
}
num_socks = 0;
break;
}
socks[num_socks++] = sock;
if (num_socks == NUM_SOCKS)
break;
}
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, SSH_LISTEN_BACKLOG) < 0) {
error("listen: %.100s", strerror(errno));
close(sock);
return -1;
}
}
/* Allocate a channel for each socket. */
*chanids = xcalloc(num_socks + 1, sizeof(**chanids));
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;
(*chanids)[n] = nc->self;
}
(*chanids)[n] = -1;
/* 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)
{
u_int display_number;
const char *display;
char buf[1024], *cp;
struct addrinfo hints, *ai, *aitop;
char strport[NI_MAXSERV];
int gaierr, sock = 0;
/* 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, "%u", &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, "%u", &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, "%u", 6000 + display_number);
if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) {
error("%.100s: unknown host. (%s)", buf,
ssh_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) {
debug2("socket: %.100s", strerror(errno));
continue;
}
/* Connect it to the display. */
if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) {
debug2("connect %.100s port %u: %.100s", buf,
6000 + display_number, strerror(errno));
close(sock);
continue;
}
/* Success */
break;
}
freeaddrinfo(aitop);
if (!ai) {
error("connect %.100s port %u: %.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.
*/
/* ARGSUSED */
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) */
/* ARGSUSED */
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 *disp,
const char *proto, const char *data)
{
u_int data_len = (u_int) strlen(data) / 2;
u_int i, value;
char *new_data;
int screen_number;
const char *cp;
u_int32_t rnd = 0;
if (x11_saved_display == NULL)
x11_saved_display = xstrdup(disp);
else if (strcmp(disp, x11_saved_display) != 0) {
error("x11_request_forwarding_with_spoofing: different "
"$DISPLAY already forwarded");
return;
}
cp = strchr(disp, ':');
if (cp)
cp = strchr(cp, '.');
if (cp)
screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL);
else
screen_number = 0;
if (x11_saved_proto == NULL) {
/* 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)
rnd = arc4random();
x11_saved_data[i] = value;
x11_fake_data[i] = rnd & 0xff;
rnd >>= 8;
}
x11_saved_data_len = data_len;
x11_fake_data_len = data_len;
}
/* Convert the fake data into hex. */
new_data = tohex(x11_fake_data, data_len);
/* 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();
}
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