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channels.c
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/* $OpenBSD: channels.c,v 1.413 2022/02/17 10:58:27 djm Exp $ */
/*
* Author: Tatu Ylonen <[email protected]>
* Copyright (c) 1995 Tatu Ylonen <[email protected]>, 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 "includes.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/un.h>
#include <sys/socket.h>
#ifdef HAVE_SYS_TIME_H
# include <sys/time.h>
#endif
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <netdb.h>
#ifdef HAVE_POLL_H
#include <poll.h>
#endif
#include <stdarg.h>
#ifdef HAVE_STDINT_H
# include <stdint.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include "openbsd-compat/sys-queue.h"
#include "xmalloc.h"
#include "ssh.h"
#include "ssh2.h"
#include "ssherr.h"
#include "sshbuf.h"
#include "packet.h"
#include "log.h"
#include "misc.h"
#include "channels.h"
#include "compat.h"
#include "canohost.h"
#include "sshkey.h"
#include "authfd.h"
#include "pathnames.h"
#include "match.h"
/* XXX remove once we're satisfied there's no lurking bugs */
/* #define DEBUG_CHANNEL_POLL 1 */
/* -- agent forwarding */
#define NUM_SOCKS 10
/* -- tcp forwarding */
/* special-case port number meaning allow any port */
#define FWD_PERMIT_ANY_PORT 0
/* special-case wildcard meaning allow any host */
#define FWD_PERMIT_ANY_HOST "*"
/* -- X11 forwarding */
/* Maximum number of fake X11 displays to try. */
#define MAX_DISPLAYS 1000
/* Per-channel callback for pre/post IO actions */
typedef void chan_fn(struct ssh *, Channel *c);
/*
* 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).
*/
/* XXX: streamlocal wants a path instead of host:port */
/* Overload host_to_connect; we could just make this match Forward */
/* XXX - can we use listen_host instead of listen_path? */
struct permission {
char *host_to_connect; /* Connect to 'host'. */
int port_to_connect; /* Connect to 'port'. */
char *listen_host; /* Remote side should listen address. */
char *listen_path; /* Remote side should listen path. */
int listen_port; /* Remote side should listen port. */
Channel *downstream; /* Downstream mux*/
};
/*
* Stores the forwarding permission state for a single direction (local or
* remote).
*/
struct permission_set {
/*
* List of all local permitted host/port pairs to allow for the
* user.
*/
u_int num_permitted_user;
struct permission *permitted_user;
/*
* List of all permitted host/port pairs to allow for the admin.
*/
u_int num_permitted_admin;
struct permission *permitted_admin;
/*
* If this is true, all opens/listens 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.
*/
int all_permitted;
};
/* Master structure for channels state */
struct ssh_channels {
/*
* Pointer to an array containing all allocated channels. The array
* is dynamically extended as needed.
*/
Channel **channels;
/*
* Size of the channel array. All slots of the array must always be
* initialized (at least the type field); unused slots set to NULL
*/
u_int channels_alloc;
/*
* 'channel_pre*' are called just before IO to add any bits
* relevant to channels in the c->io_want bitmasks.
*
* 'channel_post*': perform any appropriate operations for
* channels which have c->io_ready events pending.
*/
chan_fn **channel_pre;
chan_fn **channel_post;
/* -- tcp forwarding */
struct permission_set local_perms;
struct permission_set remote_perms;
/* -- X11 forwarding */
/* Saved X11 local (client) display. */
char *x11_saved_display;
/* Saved X11 authentication protocol name. */
char *x11_saved_proto;
/* Saved X11 authentication data. This is the real data. */
char *x11_saved_data;
u_int x11_saved_data_len;
/* Deadline after which all X11 connections are refused */
u_int x11_refuse_time;
/*
* Fake X11 authentication data. This is what the server will be
* sending us; we should replace any occurrences of this by the
* real data.
*/
u_char *x11_fake_data;
u_int x11_fake_data_len;
/* AF_UNSPEC or AF_INET or AF_INET6 */
int IPv4or6;
};
/* helper */
static void port_open_helper(struct ssh *ssh, Channel *c, char *rtype);
static const char *channel_rfwd_bind_host(const char *listen_host);
/* non-blocking connect helpers */
static int connect_next(struct channel_connect *);
static void channel_connect_ctx_free(struct channel_connect *);
static Channel *rdynamic_connect_prepare(struct ssh *, char *, char *);
static int rdynamic_connect_finish(struct ssh *, Channel *);
/* Setup helper */
static void channel_handler_init(struct ssh_channels *sc);
/* -- channel core */
void
channel_init_channels(struct ssh *ssh)
{
struct ssh_channels *sc;
if ((sc = calloc(1, sizeof(*sc))) == NULL)
fatal_f("allocation failed");
sc->channels_alloc = 10;
sc->channels = xcalloc(sc->channels_alloc, sizeof(*sc->channels));
sc->IPv4or6 = AF_UNSPEC;
channel_handler_init(sc);
ssh->chanctxt = sc;
}
Channel *
channel_by_id(struct ssh *ssh, int id)
{
Channel *c;
if (id < 0 || (u_int)id >= ssh->chanctxt->channels_alloc) {
logit_f("%d: bad id", id);
return NULL;
}
c = ssh->chanctxt->channels[id];
if (c == NULL) {
logit_f("%d: bad id: channel free", id);
return NULL;
}
return c;
}
Channel *
channel_by_remote_id(struct ssh *ssh, u_int remote_id)
{
Channel *c;
u_int i;
for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
c = ssh->chanctxt->channels[i];
if (c != NULL && c->have_remote_id && c->remote_id == remote_id)
return c;
}
return NULL;
}
/*
* Returns the channel if it is allowed to receive protocol messages.
* Private channels, like listening sockets, may not receive messages.
*/
Channel *
channel_lookup(struct ssh *ssh, int id)
{
Channel *c;
if ((c = channel_by_id(ssh, 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_RDYNAMIC_OPEN:
case SSH_CHANNEL_RDYNAMIC_FINISH:
case SSH_CHANNEL_OPENING:
case SSH_CHANNEL_OPEN:
case SSH_CHANNEL_ABANDONED:
case SSH_CHANNEL_MUX_PROXY:
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(struct ssh *ssh, Channel *c, int rfd, int wfd, int efd,
int extusage, int nonblock, int is_tty)
{
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);
#ifdef _AIX
/* XXX: Later AIX versions can't push as much data to tty */
c->wfd_isatty = is_tty || isatty(c->wfd);
#endif
/* enable nonblocking mode */
c->restore_block = 0;
if (nonblock == CHANNEL_NONBLOCK_STDIO) {
/*
* Special handling for stdio file descriptors: do not set
* non-blocking mode if they are TTYs. Otherwise prepare to
* restore their blocking state on exit to avoid interfering
* with other programs that follow.
*/
if (rfd != -1 && !isatty(rfd) && fcntl(rfd, F_GETFL) == 0) {
c->restore_block |= CHANNEL_RESTORE_RFD;
set_nonblock(rfd);
}
if (wfd != -1 && !isatty(wfd) && fcntl(wfd, F_GETFL) == 0) {
c->restore_block |= CHANNEL_RESTORE_WFD;
set_nonblock(wfd);
}
if (efd != -1 && !isatty(efd) && fcntl(efd, F_GETFL) == 0) {
c->restore_block |= CHANNEL_RESTORE_EFD;
set_nonblock(efd);
}
} else 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(struct ssh *ssh, char *ctype, int type, int rfd, int wfd, int efd,
u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock)
{
struct ssh_channels *sc = ssh->chanctxt;
u_int i, found;
Channel *c;
int r;
/* Try to find a free slot where to put the new channel. */
for (i = 0; i < sc->channels_alloc; i++) {
if (sc->channels[i] == NULL) {
/* Found a free slot. */
found = i;
break;
}
}
if (i >= sc->channels_alloc) {
/*
* There are no free slots. Take last+1 slot and expand
* the array.
*/
found = sc->channels_alloc;
if (sc->channels_alloc > CHANNELS_MAX_CHANNELS)
fatal_f("internal error: channels_alloc %d too big",
sc->channels_alloc);
sc->channels = xrecallocarray(sc->channels, sc->channels_alloc,
sc->channels_alloc + 10, sizeof(*sc->channels));
sc->channels_alloc += 10;
debug2("channel: expanding %d", sc->channels_alloc);
}
/* Initialize and return new channel. */
c = sc->channels[found] = xcalloc(1, sizeof(Channel));
if ((c->input = sshbuf_new()) == NULL ||
(c->output = sshbuf_new()) == NULL ||
(c->extended = sshbuf_new()) == NULL)
fatal_f("sshbuf_new failed");
if ((r = sshbuf_set_max_size(c->input, CHAN_INPUT_MAX)) != 0)
fatal_fr(r, "sshbuf_set_max_size");
c->ostate = CHAN_OUTPUT_OPEN;
c->istate = CHAN_INPUT_OPEN;
channel_register_fds(ssh, 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_maxpacket = maxpack;
c->remote_name = xstrdup(remote_name);
c->ctl_chan = -1;
c->delayed = 1; /* prevent call to channel_post handler */
TAILQ_INIT(&c->status_confirms);
debug("channel %d: new [%s]", found, remote_name);
return c;
}
int
channel_close_fd(struct ssh *ssh, Channel *c, int *fdp)
{
int ret, fd = *fdp;
if (fd == -1)
return 0;
if ((*fdp == c->rfd && (c->restore_block & CHANNEL_RESTORE_RFD) != 0) ||
(*fdp == c->wfd && (c->restore_block & CHANNEL_RESTORE_WFD) != 0) ||
(*fdp == c->efd && (c->restore_block & CHANNEL_RESTORE_EFD) != 0))
(void)fcntl(*fdp, F_SETFL, 0); /* restore blocking */
if (*fdp == c->rfd) {
c->io_want &= ~SSH_CHAN_IO_RFD;
c->io_ready &= ~SSH_CHAN_IO_RFD;
c->rfd = -1;
}
if (*fdp == c->wfd) {
c->io_want &= ~SSH_CHAN_IO_WFD;
c->io_ready &= ~SSH_CHAN_IO_WFD;
c->wfd = -1;
}
if (*fdp == c->efd) {
c->io_want &= ~SSH_CHAN_IO_EFD;
c->io_ready &= ~SSH_CHAN_IO_EFD;
c->efd = -1;
}
if (*fdp == c->sock) {
c->io_want &= ~SSH_CHAN_IO_SOCK;
c->io_ready &= ~SSH_CHAN_IO_SOCK;
c->sock = -1;
}
ret = close(fd);
*fdp = -1; /* probably redundant */
return ret;
}
/* Close all channel fd/socket. */
static void
channel_close_fds(struct ssh *ssh, Channel *c)
{
int sock = c->sock, rfd = c->rfd, wfd = c->wfd, efd = c->efd;
channel_close_fd(ssh, c, &c->sock);
if (rfd != sock)
channel_close_fd(ssh, c, &c->rfd);
if (wfd != sock && wfd != rfd)
channel_close_fd(ssh, c, &c->wfd);
if (efd != sock && efd != rfd && efd != wfd)
channel_close_fd(ssh, c, &c->efd);
}
static void
fwd_perm_clear(struct permission *perm)
{
free(perm->host_to_connect);
free(perm->listen_host);
free(perm->listen_path);
memset(perm, 0, sizeof(*perm));
}
/* Returns an printable name for the specified forwarding permission list */
static const char *
fwd_ident(int who, int where)
{
if (who == FORWARD_ADM) {
if (where == FORWARD_LOCAL)
return "admin local";
else if (where == FORWARD_REMOTE)
return "admin remote";
} else if (who == FORWARD_USER) {
if (where == FORWARD_LOCAL)
return "user local";
else if (where == FORWARD_REMOTE)
return "user remote";
}
fatal("Unknown forward permission list %d/%d", who, where);
}
/* Returns the forwarding permission list for the specified direction */
static struct permission_set *
permission_set_get(struct ssh *ssh, int where)
{
struct ssh_channels *sc = ssh->chanctxt;
switch (where) {
case FORWARD_LOCAL:
return &sc->local_perms;
break;
case FORWARD_REMOTE:
return &sc->remote_perms;
break;
default:
fatal_f("invalid forwarding direction %d", where);
}
}
/* Returns pointers to the specified forwarding list and its element count */
static void
permission_set_get_array(struct ssh *ssh, int who, int where,
struct permission ***permpp, u_int **npermpp)
{
struct permission_set *pset = permission_set_get(ssh, where);
switch (who) {
case FORWARD_USER:
*permpp = &pset->permitted_user;
*npermpp = &pset->num_permitted_user;
break;
case FORWARD_ADM:
*permpp = &pset->permitted_admin;
*npermpp = &pset->num_permitted_admin;
break;
default:
fatal_f("invalid forwarding client %d", who);
}
}
/* Adds an entry to the specified forwarding list */
static int
permission_set_add(struct ssh *ssh, int who, int where,
const char *host_to_connect, int port_to_connect,
const char *listen_host, const char *listen_path, int listen_port,
Channel *downstream)
{
struct permission **permp;
u_int n, *npermp;
permission_set_get_array(ssh, who, where, &permp, &npermp);
if (*npermp >= INT_MAX)
fatal_f("%s overflow", fwd_ident(who, where));
*permp = xrecallocarray(*permp, *npermp, *npermp + 1, sizeof(**permp));
n = (*npermp)++;
#define MAYBE_DUP(s) ((s == NULL) ? NULL : xstrdup(s))
(*permp)[n].host_to_connect = MAYBE_DUP(host_to_connect);
(*permp)[n].port_to_connect = port_to_connect;
(*permp)[n].listen_host = MAYBE_DUP(listen_host);
(*permp)[n].listen_path = MAYBE_DUP(listen_path);
(*permp)[n].listen_port = listen_port;
(*permp)[n].downstream = downstream;
#undef MAYBE_DUP
return (int)n;
}
static void
mux_remove_remote_forwardings(struct ssh *ssh, Channel *c)
{
struct ssh_channels *sc = ssh->chanctxt;
struct permission_set *pset = &sc->local_perms;
struct permission *perm;
int r;
u_int i;
for (i = 0; i < pset->num_permitted_user; i++) {
perm = &pset->permitted_user[i];
if (perm->downstream != c)
continue;
/* cancel on the server, since mux client is gone */
debug("channel %d: cleanup remote forward for %s:%u",
c->self, perm->listen_host, perm->listen_port);
if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
(r = sshpkt_put_cstring(ssh,
"cancel-tcpip-forward")) != 0 ||
(r = sshpkt_put_u8(ssh, 0)) != 0 ||
(r = sshpkt_put_cstring(ssh,
channel_rfwd_bind_host(perm->listen_host))) != 0 ||
(r = sshpkt_put_u32(ssh, perm->listen_port)) != 0 ||
(r = sshpkt_send(ssh)) != 0) {
fatal_fr(r, "channel %i", c->self);
}
fwd_perm_clear(perm); /* unregister */
}
}
/* Free the channel and close its fd/socket. */
void
channel_free(struct ssh *ssh, Channel *c)
{
struct ssh_channels *sc = ssh->chanctxt;
char *s;
u_int i, n;
Channel *other;
struct channel_confirm *cc;
for (n = 0, i = 0; i < sc->channels_alloc; i++) {
if ((other = sc->channels[i]) == NULL)
continue;
n++;
/* detach from mux client and prepare for closing */
if (c->type == SSH_CHANNEL_MUX_CLIENT &&
other->type == SSH_CHANNEL_MUX_PROXY &&
other->mux_ctx == c) {
other->mux_ctx = NULL;
other->type = SSH_CHANNEL_OPEN;
other->istate = CHAN_INPUT_CLOSED;
other->ostate = CHAN_OUTPUT_CLOSED;
}
}
debug("channel %d: free: %s, nchannels %u", c->self,
c->remote_name ? c->remote_name : "???", n);
if (c->type == SSH_CHANNEL_MUX_CLIENT) {
mux_remove_remote_forwardings(ssh, c);
free(c->mux_ctx);
c->mux_ctx = NULL;
} else if (c->type == SSH_CHANNEL_MUX_LISTENER) {
free(c->mux_ctx);
c->mux_ctx = NULL;
}
if (log_level_get() >= SYSLOG_LEVEL_DEBUG3) {
s = channel_open_message(ssh);
debug3("channel %d: status: %s", c->self, s);
free(s);
}
channel_close_fds(ssh, c);
sshbuf_free(c->input);
sshbuf_free(c->output);
sshbuf_free(c->extended);
c->input = c->output = c->extended = NULL;
free(c->remote_name);
c->remote_name = NULL;
free(c->path);
c->path = NULL;
free(c->listening_addr);
c->listening_addr = NULL;
while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) {
if (cc->abandon_cb != NULL)
cc->abandon_cb(ssh, c, cc->ctx);
TAILQ_REMOVE(&c->status_confirms, cc, entry);
freezero(cc, sizeof(*cc));
}
if (c->filter_cleanup != NULL && c->filter_ctx != NULL)
c->filter_cleanup(ssh, c->self, c->filter_ctx);
sc->channels[c->self] = NULL;
freezero(c, sizeof(*c));
}
void
channel_free_all(struct ssh *ssh)
{
u_int i;
struct ssh_channels *sc = ssh->chanctxt;
for (i = 0; i < sc->channels_alloc; i++)
if (sc->channels[i] != NULL)
channel_free(ssh, sc->channels[i]);
free(sc->channels);
sc->channels = NULL;
sc->channels_alloc = 0;
free(sc->x11_saved_display);
sc->x11_saved_display = NULL;
free(sc->x11_saved_proto);
sc->x11_saved_proto = NULL;
free(sc->x11_saved_data);
sc->x11_saved_data = NULL;
sc->x11_saved_data_len = 0;
free(sc->x11_fake_data);
sc->x11_fake_data = NULL;
sc->x11_fake_data_len = 0;
}
/*
* Closes the sockets/fds of all channels. This is used to close extra file
* descriptors after a fork.
*/
void
channel_close_all(struct ssh *ssh)
{
u_int i;
for (i = 0; i < ssh->chanctxt->channels_alloc; i++)
if (ssh->chanctxt->channels[i] != NULL)
channel_close_fds(ssh, ssh->chanctxt->channels[i]);
}
/*
* Stop listening to channels.
*/
void
channel_stop_listening(struct ssh *ssh)
{
u_int i;
Channel *c;
for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
c = ssh->chanctxt->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:
case SSH_CHANNEL_UNIX_LISTENER:
case SSH_CHANNEL_RUNIX_LISTENER:
channel_close_fd(ssh, c, &c->sock);
channel_free(ssh, 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(struct ssh *ssh)
{
u_int i;
u_int maxsize = ssh_packet_get_maxsize(ssh);
Channel *c;
for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
c = ssh->chanctxt->channels[i];
if (c == NULL || c->type != SSH_CHANNEL_OPEN)
continue;
if (sshbuf_len(c->output) > maxsize) {
debug2("channel %d: big output buffer %zu > %u",
c->self, sshbuf_len(c->output), maxsize);
return 0;
}
}
return 1;
}
/* Returns true if any channel is still open. */
int
channel_still_open(struct ssh *ssh)
{
u_int i;
Channel *c;
for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
c = ssh->chanctxt->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_RDYNAMIC_OPEN:
case SSH_CHANNEL_CONNECTING:
case SSH_CHANNEL_ZOMBIE:
case SSH_CHANNEL_ABANDONED:
case SSH_CHANNEL_UNIX_LISTENER:
case SSH_CHANNEL_RUNIX_LISTENER:
continue;
case SSH_CHANNEL_LARVAL:
continue;
case SSH_CHANNEL_OPENING:
case SSH_CHANNEL_OPEN:
case SSH_CHANNEL_RDYNAMIC_FINISH:
case SSH_CHANNEL_X11_OPEN:
case SSH_CHANNEL_MUX_CLIENT:
case SSH_CHANNEL_MUX_PROXY:
return 1;
default:
fatal_f("bad channel type %d", c->type);
/* NOTREACHED */
}
}
return 0;
}
/* Returns the id of an open channel suitable for keepaliving */
int
channel_find_open(struct ssh *ssh)
{
u_int i;
Channel *c;
for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
c = ssh->chanctxt->channels[i];
if (c == NULL || !c->have_remote_id)
continue;
switch (c->type) {
case SSH_CHANNEL_CLOSED:
case SSH_CHANNEL_DYNAMIC:
case SSH_CHANNEL_RDYNAMIC_OPEN:
case SSH_CHANNEL_RDYNAMIC_FINISH:
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_MUX_PROXY:
case SSH_CHANNEL_OPENING:
case SSH_CHANNEL_CONNECTING:
case SSH_CHANNEL_ZOMBIE:
case SSH_CHANNEL_ABANDONED:
case SSH_CHANNEL_UNIX_LISTENER:
case SSH_CHANNEL_RUNIX_LISTENER:
continue;
case SSH_CHANNEL_LARVAL:
case SSH_CHANNEL_AUTH_SOCKET:
case SSH_CHANNEL_OPEN:
case SSH_CHANNEL_X11_OPEN:
return i;
default:
fatal_f("bad channel type %d", c->type);
/* NOTREACHED */
}
}
return -1;
}
/* Returns the state of the channel's extended usage flag */
const char *
channel_format_extended_usage(const Channel *c)
{
if (c->efd == -1)
return "closed";
switch (c->extended_usage) {
case CHAN_EXTENDED_WRITE:
return "write";
case CHAN_EXTENDED_READ:
return "read";
case CHAN_EXTENDED_IGNORE:
return "ignore";
default:
return "UNKNOWN";
}
}
static char *
channel_format_status(const Channel *c)
{
char *ret = NULL;
xasprintf(&ret, "t%d %s%u i%u/%zu o%u/%zu e[%s]/%zu "
"fd %d/%d/%d sock %d cc %d io 0x%02x/0x%02x",
c->type,
c->have_remote_id ? "r" : "nr", c->remote_id,
c->istate, sshbuf_len(c->input),
c->ostate, sshbuf_len(c->output),
channel_format_extended_usage(c), sshbuf_len(c->extended),
c->rfd, c->wfd, c->efd, c->sock, c->ctl_chan,
c->io_want, c->io_ready);
return ret;
}
/*
* 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(struct ssh *ssh)
{
struct sshbuf *buf;
Channel *c;
u_int i;
int r;
char *cp, *ret;
if ((buf = sshbuf_new()) == NULL)
fatal_f("sshbuf_new");
if ((r = sshbuf_putf(buf,
"The following connections are open:\r\n")) != 0)
fatal_fr(r, "sshbuf_putf");
for (i = 0; i < ssh->chanctxt->channels_alloc; i++) {
c = ssh->chanctxt->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_ABANDONED:
case SSH_CHANNEL_MUX_LISTENER:
case SSH_CHANNEL_UNIX_LISTENER:
case SSH_CHANNEL_RUNIX_LISTENER:
continue;
case SSH_CHANNEL_LARVAL:
case SSH_CHANNEL_OPENING:
case SSH_CHANNEL_CONNECTING:
case SSH_CHANNEL_DYNAMIC:
case SSH_CHANNEL_RDYNAMIC_OPEN:
case SSH_CHANNEL_RDYNAMIC_FINISH:
case SSH_CHANNEL_OPEN:
case SSH_CHANNEL_X11_OPEN:
case SSH_CHANNEL_MUX_PROXY:
case SSH_CHANNEL_MUX_CLIENT:
cp = channel_format_status(c);
if ((r = sshbuf_putf(buf, " #%d %.300s (%s)\r\n",
c->self, c->remote_name, cp)) != 0) {
free(cp);
fatal_fr(r, "sshbuf_putf");
}
free(cp);
continue;
default:
fatal_f("bad channel type %d", c->type);
/* NOTREACHED */
}
}
if ((ret = sshbuf_dup_string(buf)) == NULL)
fatal_f("sshbuf_dup_string");
sshbuf_free(buf);
return ret;
}
static void
open_preamble(struct ssh *ssh, const char *where, Channel *c, const char *type)
{
int r;
if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 ||
(r = sshpkt_put_cstring(ssh, type)) != 0 ||
(r = sshpkt_put_u32(ssh, c->self)) != 0 ||
(r = sshpkt_put_u32(ssh, c->local_window)) != 0 ||
(r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0) {
fatal_r(r, "%s: channel %i: open", where, c->self);
}
}
void
channel_send_open(struct ssh *ssh, int id)
{
Channel *c = channel_lookup(ssh, id);
int r;
if (c == NULL) {
logit("channel_send_open: %d: bad id", id);
return;
}
debug2("channel %d: send open", id);
open_preamble(ssh, __func__, c, c->ctype);
if ((r = sshpkt_send(ssh)) != 0)
fatal_fr(r, "channel %i", c->self);
}
void
channel_request_start(struct ssh *ssh, int id, char *service, int wantconfirm)
{
Channel *c = channel_lookup(ssh, id);
int r;
if (c == NULL) {
logit_f("%d: unknown channel id", id);
return;
}
if (!c->have_remote_id)
fatal_f("channel %d: no remote id", c->self);
debug2("channel %d: request %s confirm %d", id, service, wantconfirm);
if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_REQUEST)) != 0 ||
(r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
(r = sshpkt_put_cstring(ssh, service)) != 0 ||
(r = sshpkt_put_u8(ssh, wantconfirm)) != 0) {
fatal_fr(r, "channel %i", c->self);
}
}
void
channel_register_status_confirm(struct ssh *ssh, int id,
channel_confirm_cb *cb, channel_confirm_abandon_cb *abandon_cb, void *ctx)
{
struct channel_confirm *cc;
Channel *c;
if ((c = channel_lookup(ssh, id)) == NULL)