| /* $OpenBSD: channels.c,v 1.389 2019/01/19 21:37:13 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 "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> |
| #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" |
| |
| /* -- 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 select() actions */ |
| typedef void chan_fn(struct ssh *, Channel *c, |
| fd_set *readset, fd_set *writeset); |
| |
| /* |
| * 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; |
| |
| /* |
| * Maximum file descriptor value used in any of the channels. This is |
| * updated in channel_new. |
| */ |
| int channel_max_fd; |
| |
| /* |
| * '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. |
| */ |
| 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("%s: allocation failed", __func__); |
| 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("%s: %d: bad id", __func__, id); |
| return NULL; |
| } |
| c = ssh->chanctxt->channels[id]; |
| if (c == NULL) { |
| logit("%s: %d: bad id: channel free", __func__, 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) |
| { |
| struct ssh_channels *sc = ssh->chanctxt; |
| |
| /* Update the maximum file descriptor value. */ |
| sc->channel_max_fd = MAXIMUM(sc->channel_max_fd, rfd); |
| sc->channel_max_fd = MAXIMUM(sc->channel_max_fd, wfd); |
| sc->channel_max_fd = MAXIMUM(sc->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); |
| #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 */ |
| 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; |
| |
| /* 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("%s: internal error: channels_alloc %d too big", |
| __func__, 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("%s: sshbuf_new failed", __func__); |
| 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; |
| } |
| |
| static void |
| channel_find_maxfd(struct ssh_channels *sc) |
| { |
| u_int i; |
| int max = 0; |
| Channel *c; |
| |
| for (i = 0; i < sc->channels_alloc; i++) { |
| c = sc->channels[i]; |
| if (c != NULL) { |
| max = MAXIMUM(max, c->rfd); |
| max = MAXIMUM(max, c->wfd); |
| max = MAXIMUM(max, c->efd); |
| } |
| } |
| sc->channel_max_fd = max; |
| } |
| |
| int |
| channel_close_fd(struct ssh *ssh, int *fdp) |
| { |
| struct ssh_channels *sc = ssh->chanctxt; |
| int ret = 0, fd = *fdp; |
| |
| if (fd != -1) { |
| ret = close(fd); |
| *fdp = -1; |
| if (fd == sc->channel_max_fd) |
| channel_find_maxfd(sc); |
| } |
| 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->sock); |
| if (rfd != sock) |
| channel_close_fd(ssh, &c->rfd); |
| if (wfd != sock && wfd != rfd) |
| channel_close_fd(ssh, &c->wfd); |
| if (efd != sock && efd != rfd && efd != wfd) |
| channel_close_fd(ssh, &c->efd); |
| } |
| |
| static void |
| fwd_perm_clear(struct permission *perm) |
| { |
| free(perm->host_to_connect); |
| free(perm->listen_host); |
| free(perm->listen_path); |
| bzero(perm, 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("%s: invalid forwarding direction %d", __func__, where); |
| } |
| } |
| |
| /* Reutrns 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("%s: invalid forwarding client %d", __func__, who); |
| } |
| } |
| |
| /* Adds an entry to the spcified 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("%s: %s overflow", __func__, 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("%s: channel %i: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| 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); |
| |
| 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); |
| explicit_bzero(cc, sizeof(*cc)); |
| free(cc); |
| } |
| if (c->filter_cleanup != NULL && c->filter_ctx != NULL) |
| c->filter_cleanup(ssh, c->self, c->filter_ctx); |
| sc->channels[c->self] = NULL; |
| explicit_bzero(c, sizeof(*c)); |
| free(c); |
| } |
| |
| void |
| channel_free_all(struct ssh *ssh) |
| { |
| u_int i; |
| |
| for (i = 0; i < ssh->chanctxt->channels_alloc; i++) |
| if (ssh->chanctxt->channels[i] != NULL) |
| channel_free(ssh, ssh->chanctxt->channels[i]); |
| } |
| |
| /* |
| * 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->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("%s: bad channel type %d", __func__, 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("%s: bad channel type %d", __func__, 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", |
| 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); |
| 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("%s: sshbuf_new", __func__); |
| if ((r = sshbuf_putf(buf, |
| "The following connections are open:\r\n")) != 0) |
| fatal("%s: sshbuf_putf: %s", __func__, ssh_err(r)); |
| 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("%s: sshbuf_putf: %s", |
| __func__, ssh_err(r)); |
| } |
| free(cp); |
| continue; |
| default: |
| fatal("%s: bad channel type %d", __func__, c->type); |
| /* NOTREACHED */ |
| } |
| } |
| if ((ret = sshbuf_dup_string(buf)) == NULL) |
| fatal("%s: sshbuf_dup_string", __func__); |
| 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("%s: channel %i: open: %s", where, c->self, ssh_err(r)); |
| } |
| } |
| |
| 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("%s: channel %i: %s", __func__, c->self, ssh_err(r)); |
| } |
| |
| 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("%s: %d: unknown channel id", __func__, id); |
| return; |
| } |
| if (!c->have_remote_id) |
| fatal(":%s: channel %d: no remote id", __func__, 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("%s: channel %i: %s", __func__, c->self, ssh_err(r)); |
| } |
| } |
| |
| 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) |
| fatal("%s: %d: bad id", __func__, id); |
| |
| cc = xcalloc(1, 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(struct ssh *ssh, int id, |
| channel_open_fn *fn, void *ctx) |
| { |
| Channel *c = channel_lookup(ssh, id); |
| |
| if (c == NULL) { |
| logit("%s: %d: bad id", __func__, id); |
| return; |
| } |
| c->open_confirm = fn; |
| c->open_confirm_ctx = ctx; |
| } |
| |
| void |
| channel_register_cleanup(struct ssh *ssh, int id, |
| channel_callback_fn *fn, int do_close) |
| { |
| Channel *c = channel_by_id(ssh, id); |
| |
| if (c == NULL) { |
| logit("%s: %d: bad id", __func__, id); |
| return; |
| } |
| c->detach_user = fn; |
| c->detach_close = do_close; |
| } |
| |
| void |
| channel_cancel_cleanup(struct ssh *ssh, int id) |
| { |
| Channel *c = channel_by_id(ssh, id); |
| |
| if (c == NULL) { |
| logit("%s: %d: bad id", __func__, id); |
| return; |
| } |
| c->detach_user = NULL; |
| c->detach_close = 0; |
| } |
| |
| void |
| channel_register_filter(struct ssh *ssh, int id, channel_infilter_fn *ifn, |
| channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) |
| { |
| Channel *c = channel_lookup(ssh, id); |
| |
| if (c == NULL) { |
| logit("%s: %d: bad id", __func__, id); |
| return; |
| } |
| c->input_filter = ifn; |
| c->output_filter = ofn; |
| c->filter_ctx = ctx; |
| c->filter_cleanup = cfn; |
| } |
| |
| void |
| channel_set_fds(struct ssh *ssh, int id, int rfd, int wfd, int efd, |
| int extusage, int nonblock, int is_tty, u_int window_max) |
| { |
| Channel *c = channel_lookup(ssh, id); |
| int r; |
| |
| if (c == NULL || c->type != SSH_CHANNEL_LARVAL) |
| fatal("channel_activate for non-larval channel %d.", id); |
| if (!c->have_remote_id) |
| fatal(":%s: channel %d: no remote id", __func__, c->self); |
| |
| channel_register_fds(ssh, c, rfd, wfd, efd, extusage, nonblock, is_tty); |
| c->type = SSH_CHANNEL_OPEN; |
| c->local_window = c->local_window_max = window_max; |
| |
| if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); |
| } |
| |
| static void |
| channel_pre_listener(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| FD_SET(c->sock, readset); |
| } |
| |
| static void |
| channel_pre_connecting(struct ssh *ssh, 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(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| if (c->istate == CHAN_INPUT_OPEN && |
| c->remote_window > 0 && |
| sshbuf_len(c->input) < c->remote_window && |
| sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) |
| FD_SET(c->rfd, readset); |
| if (c->ostate == CHAN_OUTPUT_OPEN || |
| c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { |
| if (sshbuf_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/(%zu)", c->self, |
| c->efd, sshbuf_len(c->extended)); |
| else |
| chan_obuf_empty(ssh, c); |
| } |
| } |
| /** XXX check close conditions, too */ |
| if (c->efd != -1 && !(c->istate == CHAN_INPUT_CLOSED && |
| c->ostate == CHAN_OUTPUT_CLOSED)) { |
| if (c->extended_usage == CHAN_EXTENDED_WRITE && |
| sshbuf_len(c->extended) > 0) |
| FD_SET(c->efd, writeset); |
| else if (c->efd != -1 && !(c->flags & CHAN_EOF_SENT) && |
| (c->extended_usage == CHAN_EXTENDED_READ || |
| c->extended_usage == CHAN_EXTENDED_IGNORE) && |
| sshbuf_len(c->extended) < c->remote_window) |
| FD_SET(c->efd, readset); |
| } |
| /* XXX: What about efd? races? */ |
| } |
| |
| /* |
| * 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(struct ssh *ssh, struct sshbuf *b) |
| { |
| struct ssh_channels *sc = ssh->chanctxt; |
| u_char *ucp; |
| u_int proto_len, data_len; |
| |
| /* Is this being called after the refusal deadline? */ |
| if (sc->x11_refuse_time != 0 && |
| (u_int)monotime() >= sc->x11_refuse_time) { |
| verbose("Rejected X11 connection after ForwardX11Timeout " |
| "expired"); |
| return -1; |
| } |
| |
| /* Check if the fixed size part of the packet is in buffer. */ |
| if (sshbuf_len(b) < 12) |
| return 0; |
| |
| /* Parse the lengths of variable-length fields. */ |
| ucp = sshbuf_mutable_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 (sshbuf_len(b) < |
| 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) |
| return 0; |
| |
| /* Check if authentication protocol matches. */ |
| if (proto_len != strlen(sc->x11_saved_proto) || |
| memcmp(ucp + 12, sc->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 != sc->x11_fake_data_len || |
| timingsafe_bcmp(ucp + 12 + ((proto_len + 3) & ~3), |
| sc->x11_fake_data, sc->x11_fake_data_len) != 0) { |
| debug2("X11 auth data does not match fake data."); |
| return -1; |
| } |
| /* Check fake data length */ |
| if (sc->x11_fake_data_len != sc->x11_saved_data_len) { |
| error("X11 fake_data_len %d != saved_data_len %d", |
| sc->x11_fake_data_len, sc->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), |
| sc->x11_saved_data, sc->x11_saved_data_len); |
| return 1; |
| } |
| |
| static void |
| channel_pre_x11_open(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| int ret = x11_open_helper(ssh, c->output); |
| |
| /* c->force_drain = 1; */ |
| |
| if (ret == 1) { |
| c->type = SSH_CHANNEL_OPEN; |
| channel_pre_open(ssh, 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(ssh, c); |
| sshbuf_reset(c->input); |
| chan_ibuf_empty(ssh, c); |
| sshbuf_reset(c->output); |
| chan_write_failed(ssh, c); |
| debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); |
| } |
| } |
| |
| static void |
| channel_pre_mux_client(struct ssh *ssh, |
| Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| if (c->istate == CHAN_INPUT_OPEN && !c->mux_pause && |
| sshbuf_check_reserve(c->input, CHAN_RBUF) == 0) |
| FD_SET(c->rfd, readset); |
| if (c->istate == CHAN_INPUT_WAIT_DRAIN) { |
| /* clear buffer immediately (discard any partial packet) */ |
| sshbuf_reset(c->input); |
| chan_ibuf_empty(ssh, c); |
| /* Start output drain. XXX just kill chan? */ |
| chan_rcvd_oclose(ssh, c); |
| } |
| if (c->ostate == CHAN_OUTPUT_OPEN || |
| c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { |
| if (sshbuf_len(c->output) > 0) |
| FD_SET(c->wfd, writeset); |
| else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) |
| chan_obuf_empty(ssh, c); |
| } |
| } |
| |
| /* try to decode a socks4 header */ |
| static int |
| channel_decode_socks4(Channel *c, struct sshbuf *input, struct sshbuf *output) |
| { |
| const u_char *p; |
| char *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; |
| int r; |
| |
| debug2("channel %d: decode socks4", c->self); |
| |
| have = sshbuf_len(input); |
| len = sizeof(s4_req); |
| if (have < len) |
| return 0; |
| p = sshbuf_ptr(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; |
| if ((r = sshbuf_get(input, &s4_req.version, 1)) != 0 || |
| (r = sshbuf_get(input, &s4_req.command, 1)) != 0 || |
| (r = sshbuf_get(input, &s4_req.dest_port, 2)) != 0 || |
| (r = sshbuf_get(input, &s4_req.dest_addr, 4)) != 0) { |
| debug("channels %d: decode socks4: %s", c->self, ssh_err(r)); |
| return -1; |
| } |
| have = sshbuf_len(input); |
| p = sshbuf_ptr(input); |
| if (memchr(p, '\0', have) == NULL) { |
| error("channel %d: decode socks4: user not nul terminated", |
| c->self); |
| return -1; |
| } |
| len = strlen(p); |
| debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); |
| len++; /* trailing '\0' */ |
| strlcpy(username, p, sizeof(username)); |
| if ((r = sshbuf_consume(input, len)) != 0) { |
| fatal("%s: channel %d: consume: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| free(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 = sshbuf_len(input); |
| p = sshbuf_ptr(input); |
| if (memchr(p, '\0', have) == NULL) { |
| error("channel %d: decode socks4a: host not nul " |
| "terminated", c->self); |
| return -1; |
| } |
| len = strlen(p); |
| debug2("channel %d: decode socks4a: host %s/%d", |
| c->self, p, len); |
| len++; /* trailing '\0' */ |
| if (len > NI_MAXHOST) { |
| error("channel %d: hostname \"%.100s\" too long", |
| c->self, p); |
| return -1; |
| } |
| c->path = xstrdup(p); |
| if ((r = sshbuf_consume(input, len)) != 0) { |
| fatal("%s: channel %d: consume: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| } |
| 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 */ |
| if ((r = sshbuf_put(output, &s4_rsp, sizeof(s4_rsp))) != 0) { |
| fatal("%s: channel %d: append reply: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| 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 |
| |
| static int |
| channel_decode_socks5(Channel *c, struct sshbuf *input, struct sshbuf *output) |
| { |
| /* XXX use get/put_u8 instead of trusting struct padding */ |
| 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; |
| char dest_addr[255+1], ntop[INET6_ADDRSTRLEN]; |
| const u_char *p; |
| u_int have, need, i, found, nmethods, addrlen, af; |
| int r; |
| |
| debug2("channel %d: decode socks5", c->self); |
| p = sshbuf_ptr(input); |
| if (p[0] != 0x05) |
| return -1; |
| have = sshbuf_len(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; |
| } |
| if ((r = sshbuf_consume(input, nmethods + 2)) != 0) { |
| fatal("%s: channel %d: consume: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| /* version, method */ |
| if ((r = sshbuf_put_u8(output, 0x05)) != 0 || |
| (r = sshbuf_put_u8(output, SSH_SOCKS5_NOAUTH)) != 0) { |
| fatal("%s: channel %d: append reply: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| 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; |
| if ((r = sshbuf_consume(input, sizeof(s5_req))) != 0) { |
| fatal("%s: channel %d: consume: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| if (s5_req.atyp == SSH_SOCKS5_DOMAIN) { |
| /* host string length */ |
| if ((r = sshbuf_consume(input, 1)) != 0) { |
| fatal("%s: channel %d: consume: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| } |
| if ((r = sshbuf_get(input, &dest_addr, addrlen)) != 0 || |
| (r = sshbuf_get(input, &dest_port, 2)) != 0) { |
| debug("channel %d: parse addr/port: %s", c->self, ssh_err(r)); |
| return -1; |
| } |
| dest_addr[addrlen] = '\0'; |
| free(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; |
| dest_port = 0; /* ignored */ |
| |
| if ((r = sshbuf_put(output, &s5_rsp, sizeof(s5_rsp))) != 0 || |
| (r = sshbuf_put_u32(output, ntohl(INADDR_ANY))) != 0 || |
| (r = sshbuf_put(output, &dest_port, sizeof(dest_port))) != 0) |
| fatal("%s: channel %d: append reply: %s", __func__, |
| c->self, ssh_err(r)); |
| return 1; |
| } |
| |
| Channel * |
| channel_connect_stdio_fwd(struct ssh *ssh, |
| const char *host_to_connect, u_short port_to_connect, int in, int out) |
| { |
| Channel *c; |
| |
| debug("%s %s:%d", __func__, host_to_connect, port_to_connect); |
| |
| c = channel_new(ssh, "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(ssh, c, in, out, -1, 0, 1, 0); |
| port_open_helper(ssh, c, "direct-tcpip"); |
| |
| return c; |
| } |
| |
| /* dynamic port forwarding */ |
| static void |
| channel_pre_dynamic(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| const u_char *p; |
| u_int have; |
| int ret; |
| |
| have = sshbuf_len(c->input); |
| debug2("channel %d: pre_dynamic: have %d", c->self, have); |
| /* sshbuf_dump(c->input, stderr); */ |
| /* 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 = sshbuf_ptr(c->input); |
| /* XXX sshbuf_peek_u8? */ |
| switch (p[0]) { |
| case 0x04: |
| ret = channel_decode_socks4(c, c->input, c->output); |
| break; |
| case 0x05: |
| ret = channel_decode_socks5(c, c->input, c->output); |
| break; |
| default: |
| ret = -1; |
| break; |
| } |
| if (ret < 0) { |
| chan_mark_dead(ssh, c); |
| } else if (ret == 0) { |
| debug2("channel %d: pre_dynamic: need more", c->self); |
| /* need more */ |
| FD_SET(c->sock, readset); |
| if (sshbuf_len(c->output)) |
| FD_SET(c->sock, writeset); |
| } else { |
| /* switch to the next state */ |
| c->type = SSH_CHANNEL_OPENING; |
| port_open_helper(ssh, c, "direct-tcpip"); |
| } |
| } |
| |
| /* simulate read-error */ |
| static void |
| rdynamic_close(struct ssh *ssh, Channel *c) |
| { |
| c->type = SSH_CHANNEL_OPEN; |
| chan_read_failed(ssh, c); |
| sshbuf_reset(c->input); |
| chan_ibuf_empty(ssh, c); |
| sshbuf_reset(c->output); |
| chan_write_failed(ssh, c); |
| } |
| |
| /* reverse dynamic port forwarding */ |
| static void |
| channel_before_prepare_select_rdynamic(struct ssh *ssh, Channel *c) |
| { |
| const u_char *p; |
| u_int have, len; |
| int r, ret; |
| |
| have = sshbuf_len(c->output); |
| debug2("channel %d: pre_rdynamic: have %d", c->self, have); |
| /* sshbuf_dump(c->output, stderr); */ |
| /* EOF received */ |
| if (c->flags & CHAN_EOF_RCVD) { |
| if ((r = sshbuf_consume(c->output, have)) != 0) { |
| fatal("%s: channel %d: consume: %s", |
| __func__, c->self, ssh_err(r)); |
| } |
| rdynamic_close(ssh, c); |
| return; |
| } |
| /* check if the fixed size part of the packet is in buffer. */ |
| if (have < 3) |
| return; |
| /* try to guess the protocol */ |
| p = sshbuf_ptr(c->output); |
| switch (p[0]) { |
| case 0x04: |
| /* switch input/output for reverse forwarding */ |
| ret = channel_decode_socks4(c, c->output, c->input); |
| break; |
| case 0x05: |
| ret = channel_decode_socks5(c, c->output, c->input); |
| break; |
| default: |
| ret = -1; |
| break; |
| } |
| if (ret < 0) { |
| rdynamic_close(ssh, c); |
| } else if (ret == 0) { |
| debug2("channel %d: pre_rdynamic: need more", c->self); |
| /* send socks request to peer */ |
| len = sshbuf_len(c->input); |
| if (len > 0 && len < c->remote_window) { |
| if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || |
| (r = sshpkt_put_stringb(ssh, c->input)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) { |
| fatal("%s: channel %i: rdynamic: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| if ((r = sshbuf_consume(c->input, len)) != 0) { |
| fatal("%s: channel %d: consume: %s", |
| __func__, c->self, ssh_err(r)); |
| } |
| c->remote_window -= len; |
| } |
| } else if (rdynamic_connect_finish(ssh, c) < 0) { |
| /* the connect failed */ |
| rdynamic_close(ssh, c); |
| } |
| } |
| |
| /* This is our fake X11 server socket. */ |
| static void |
| channel_post_x11_listener(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| Channel *nc; |
| struct sockaddr_storage addr; |
| int r, newsock, oerrno, remote_port; |
| socklen_t addrlen; |
| char buf[16384], *remote_ipaddr; |
| |
| if (!FD_ISSET(c->sock, readset)) |
| return; |
| |
| debug("X11 connection requested."); |
| addrlen = sizeof(addr); |
| newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); |
| if (c->single_connection) { |
| oerrno = errno; |
| debug2("single_connection: closing X11 listener."); |
| channel_close_fd(ssh, &c->sock); |
| chan_mark_dead(ssh, c); |
| errno = oerrno; |
| } |
| if (newsock < 0) { |
| if (errno != EINTR && errno != EWOULDBLOCK && |
| errno != ECONNABORTED) |
| error("accept: %.100s", strerror(errno)); |
| if (errno == EMFILE || errno == ENFILE) |
| c->notbefore = monotime() + 1; |
| 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(ssh, "accepted x11 socket", |
| SSH_CHANNEL_OPENING, newsock, newsock, -1, |
| c->local_window_max, c->local_maxpacket, 0, buf, 1); |
| open_preamble(ssh, __func__, nc, "x11"); |
| if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || |
| (r = sshpkt_put_u32(ssh, remote_port)) != 0) { |
| fatal("%s: channel %i: reply %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| if ((r = sshpkt_send(ssh)) != 0) |
| fatal("%s: channel %i: send %s", __func__, c->self, ssh_err(r)); |
| free(remote_ipaddr); |
| } |
| |
| static void |
| port_open_helper(struct ssh *ssh, Channel *c, char *rtype) |
| { |
| char *local_ipaddr = get_local_ipaddr(c->sock); |
| int local_port = c->sock == -1 ? 65536 : get_local_port(c->sock); |
| char *remote_ipaddr = get_peer_ipaddr(c->sock); |
| int remote_port = get_peer_port(c->sock); |
| int r; |
| |
| if (remote_port == -1) { |
| /* Fake addr/port to appease peers that validate it (Tectia) */ |
| free(remote_ipaddr); |
| remote_ipaddr = xstrdup("127.0.0.1"); |
| remote_port = 65535; |
| } |
| |
| free(c->remote_name); |
| xasprintf(&c->remote_name, |
| "%s: listening port %d for %.100s port %d, " |
| "connect from %.200s port %d to %.100s port %d", |
| rtype, c->listening_port, c->path, c->host_port, |
| remote_ipaddr, remote_port, local_ipaddr, local_port); |
| |
| open_preamble(ssh, __func__, c, rtype); |
| if (strcmp(rtype, "direct-tcpip") == 0) { |
| /* target host, port */ |
| if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->host_port)) != 0) { |
| fatal("%s: channel %i: reply %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| } else if (strcmp(rtype, "direct-streamlocal@openssh.com") == 0) { |
| /* target path */ |
| if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) { |
| fatal("%s: channel %i: reply %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| } else if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { |
| /* listen path */ |
| if ((r = sshpkt_put_cstring(ssh, c->path)) != 0) { |
| fatal("%s: channel %i: reply %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| } else { |
| /* listen address, port */ |
| if ((r = sshpkt_put_cstring(ssh, c->path)) != 0 || |
| (r = sshpkt_put_u32(ssh, local_port)) != 0) { |
| fatal("%s: channel %i: reply %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| } |
| if (strcmp(rtype, "forwarded-streamlocal@openssh.com") == 0) { |
| /* reserved for future owner/mode info */ |
| if ((r = sshpkt_put_cstring(ssh, "")) != 0) { |
| fatal("%s: channel %i: reply %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| } else { |
| /* originator host and port */ |
| if ((r = sshpkt_put_cstring(ssh, remote_ipaddr)) != 0 || |
| (r = sshpkt_put_u32(ssh, (u_int)remote_port)) != 0) { |
| fatal("%s: channel %i: reply %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| } |
| if ((r = sshpkt_send(ssh)) != 0) |
| fatal("%s: channel %i: send %s", __func__, c->self, ssh_err(r)); |
| free(remote_ipaddr); |
| free(local_ipaddr); |
| } |
| |
| void |
| channel_set_x11_refuse_time(struct ssh *ssh, u_int refuse_time) |
| { |
| ssh->chanctxt->x11_refuse_time = refuse_time; |
| } |
| |
| /* |
| * This socket is listening for connections to a forwarded TCP/IP port. |
| */ |
| static void |
| channel_post_port_listener(struct ssh *ssh, 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)) |
| return; |
| |
| 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->type == SSH_CHANNEL_RUNIX_LISTENER) { |
| nextstate = SSH_CHANNEL_OPENING; |
| rtype = "forwarded-streamlocal@openssh.com"; |
| } else if (c->host_port == PORT_STREAMLOCAL) { |
| nextstate = SSH_CHANNEL_OPENING; |
| rtype = "direct-streamlocal@openssh.com"; |
| } 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) { |
| if (errno != EINTR && errno != EWOULDBLOCK && |
| errno != ECONNABORTED) |
| error("accept: %.100s", strerror(errno)); |
| if (errno == EMFILE || errno == ENFILE) |
| c->notbefore = monotime() + 1; |
| return; |
| } |
| if (c->host_port != PORT_STREAMLOCAL) |
| set_nodelay(newsock); |
| nc = channel_new(ssh, 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(ssh, nc, rtype); |
| } |
| |
| /* |
| * This is the authentication agent socket listening for connections from |
| * clients. |
| */ |
| static void |
| channel_post_auth_listener(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| Channel *nc; |
| int r, newsock; |
| struct sockaddr_storage addr; |
| socklen_t addrlen; |
| |
| if (!FD_ISSET(c->sock, readset)) |
| return; |
| |
| addrlen = sizeof(addr); |
| newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); |
| if (newsock < 0) { |
| error("accept from auth socket: %.100s", strerror(errno)); |
| if (errno == EMFILE || errno == ENFILE) |
| c->notbefore = monotime() + 1; |
| return; |
| } |
| nc = channel_new(ssh, "accepted auth socket", |
| SSH_CHANNEL_OPENING, newsock, newsock, -1, |
| c->local_window_max, c->local_maxpacket, |
| 0, "accepted auth socket", 1); |
| open_preamble(ssh, __func__, nc, "auth-agent@openssh.com"); |
| if ((r = sshpkt_send(ssh)) != 0) |
| fatal("%s: channel %i: %s", __func__, c->self, ssh_err(r)); |
| } |
| |
| static void |
| channel_post_connecting(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| int err = 0, sock, isopen, r; |
| socklen_t sz = sizeof(err); |
| |
| if (!FD_ISSET(c->sock, writeset)) |
| return; |
| if (!c->have_remote_id) |
| fatal(":%s: channel %d: no remote id", __func__, c->self); |
| /* for rdynamic the OPEN_CONFIRMATION has been sent already */ |
| isopen = (c->type == SSH_CHANNEL_RDYNAMIC_FINISH); |
| 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 (isopen) { |
| /* no message necessary */ |
| } else { |
| if ((r = sshpkt_start(ssh, |
| SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->remote_id)) != 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("%s: channel %i: confirm: %s", __func__, |
| c->self, ssh_err(r)); |
| if ((r = sshpkt_send(ssh)) != 0) |
| fatal("%s: channel %i: %s", __func__, c->self, |
| ssh_err(r)); |
| } |
| } 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_find_maxfd(ssh->chanctxt); |
| 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 (isopen) { |
| rdynamic_close(ssh, c); |
| } else { |
| if ((r = sshpkt_start(ssh, |
| SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || |
| (r = sshpkt_put_u32(ssh, |
| SSH2_OPEN_CONNECT_FAILED)) != 0 || |
| (r = sshpkt_put_cstring(ssh, strerror(err))) != 0 || |
| (r = sshpkt_put_cstring(ssh, "")) != 0) { |
| fatal("%s: channel %i: failure: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| if ((r = sshpkt_send(ssh)) != 0) |
| fatal("%s: channel %i: %s", __func__, c->self, |
| ssh_err(r)); |
| chan_mark_dead(ssh, c); |
| } |
| } |
| } |
| |
| static int |
| channel_handle_rfd(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| char buf[CHAN_RBUF]; |
| ssize_t len; |
| int r, force; |
| |
| force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; |
| |
| if (c->rfd == -1 || (!force && !FD_ISSET(c->rfd, readset))) |
| return 1; |
| |
| errno = 0; |
| len = read(c->rfd, buf, sizeof(buf)); |
| if (len < 0 && (errno == EINTR || |
| ((errno == EAGAIN || errno == EWOULDBLOCK) && !force))) |
| return 1; |
| #ifndef PTY_ZEROREAD |
| if (len <= 0) { |
| #else |
| if ((!c->isatty && len <= 0) || |
| (c->isatty && (len < 0 || (len == 0 && errno != 0)))) { |
| #endif |
| debug2("channel %d: read<=0 rfd %d len %zd", |
| c->self, c->rfd, len); |
| if (c->type != SSH_CHANNEL_OPEN) { |
| debug2("channel %d: not open", c->self); |
| chan_mark_dead(ssh, c); |
| return -1; |
| } else { |
| chan_read_failed(ssh, c); |
| } |
| return -1; |
| } |
| if (c->input_filter != NULL) { |
| if (c->input_filter(ssh, c, buf, len) == -1) { |
| debug2("channel %d: filter stops", c->self); |
| chan_read_failed(ssh, c); |
| } |
| } else if (c->datagram) { |
| if ((r = sshbuf_put_string(c->input, buf, len)) != 0) |
| fatal("%s: channel %d: put datagram: %s", __func__, |
| c->self, ssh_err(r)); |
| } else if ((r = sshbuf_put(c->input, buf, len)) != 0) { |
| fatal("%s: channel %d: put data: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| return 1; |
| } |
| |
| static int |
| channel_handle_wfd(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| struct termios tio; |
| u_char *data = NULL, *buf; /* XXX const; need filter API change */ |
| size_t dlen, olen = 0; |
| int r, len; |
| |
| if (c->wfd == -1 || !FD_ISSET(c->wfd, writeset) || |
| sshbuf_len(c->output) == 0) |
| return 1; |
| |
| /* Send buffered output data to the socket. */ |
| olen = sshbuf_len(c->output); |
| if (c->output_filter != NULL) { |
| if ((buf = c->output_filter(ssh, c, &data, &dlen)) == NULL) { |
| debug2("channel %d: filter stops", c->self); |
| if (c->type != SSH_CHANNEL_OPEN) |
| chan_mark_dead(ssh, c); |
| else |
| chan_write_failed(ssh, c); |
| return -1; |
| } |
| } else if (c->datagram) { |
| if ((r = sshbuf_get_string(c->output, &data, &dlen)) != 0) |
| fatal("%s: channel %d: get datagram: %s", __func__, |
| c->self, ssh_err(r)); |
| buf = data; |
| } else { |
| buf = data = sshbuf_mutable_ptr(c->output); |
| dlen = sshbuf_len(c->output); |
| } |
| |
| if (c->datagram) { |
| /* ignore truncated writes, datagrams might get lost */ |
| len = write(c->wfd, buf, dlen); |
| free(data); |
| if (len < 0 && (errno == EINTR || errno == EAGAIN || |
| errno == EWOULDBLOCK)) |
| return 1; |
| if (len <= 0) |
| goto write_fail; |
| goto out; |
| } |
| |
| #ifdef _AIX |
| /* XXX: Later AIX versions can't push as much data to tty */ |
| if (c->wfd_isatty) |
| dlen = MIN(dlen, 8*1024); |
| #endif |
| |
| len = write(c->wfd, buf, dlen); |
| if (len < 0 && |
| (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) |
| return 1; |
| if (len <= 0) { |
| write_fail: |
| if (c->type != SSH_CHANNEL_OPEN) { |
| debug2("channel %d: not open", c->self); |
| chan_mark_dead(ssh, c); |
| return -1; |
| } else { |
| chan_write_failed(ssh, c); |
| } |
| return -1; |
| } |
| #ifndef BROKEN_TCGETATTR_ICANON |
| if (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) |
| */ |
| if ((r = sshpkt_msg_ignore(ssh, 4+len)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: channel %d: ignore: %s", |
| __func__, c->self, ssh_err(r)); |
| } |
| } |
| #endif /* BROKEN_TCGETATTR_ICANON */ |
| if ((r = sshbuf_consume(c->output, len)) != 0) { |
| fatal("%s: channel %d: consume: %s", |
| __func__, c->self, ssh_err(r)); |
| } |
| out: |
| c->local_consumed += olen - sshbuf_len(c->output); |
| |
| return 1; |
| } |
| |
| static int |
| channel_handle_efd_write(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| int r; |
| ssize_t len; |
| |
| if (!FD_ISSET(c->efd, writeset) || sshbuf_len(c->extended) == 0) |
| return 1; |
| |
| len = write(c->efd, sshbuf_ptr(c->extended), |
| sshbuf_len(c->extended)); |
| debug2("channel %d: written %zd to efd %d", c->self, len, c->efd); |
| if (len < 0 && (errno == EINTR || errno == EAGAIN || |
| errno == EWOULDBLOCK)) |
| return 1; |
| if (len <= 0) { |
| debug2("channel %d: closing write-efd %d", c->self, c->efd); |
| channel_close_fd(ssh, &c->efd); |
| } else { |
| if ((r = sshbuf_consume(c->extended, len)) != 0) { |
| fatal("%s: channel %d: consume: %s", |
| __func__, c->self, ssh_err(r)); |
| } |
| c->local_consumed += len; |
| } |
| return 1; |
| } |
| |
| static int |
| channel_handle_efd_read(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| char buf[CHAN_RBUF]; |
| ssize_t len; |
| int r, force; |
| |
| force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; |
| |
| if (c->efd == -1 || (!force && !FD_ISSET(c->efd, readset))) |
| return 1; |
| |
| len = read(c->efd, buf, sizeof(buf)); |
| debug2("channel %d: read %zd from efd %d", c->self, len, c->efd); |
| if (len < 0 && (errno == EINTR || ((errno == EAGAIN || |
| errno == EWOULDBLOCK) && !force))) |
| return 1; |
| if (len <= 0) { |
| debug2("channel %d: closing read-efd %d", |
| c->self, c->efd); |
| channel_close_fd(ssh, &c->efd); |
| } else { |
| if (c->extended_usage == CHAN_EXTENDED_IGNORE) { |
| debug3("channel %d: discard efd", |
| c->self); |
| } else if ((r = sshbuf_put(c->extended, buf, len)) != 0) { |
| fatal("%s: channel %d: append: %s", |
| __func__, c->self, ssh_err(r)); |
| } |
| } |
| return 1; |
| } |
| |
| static int |
| channel_handle_efd(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| if (c->efd == -1) |
| return 1; |
| |
| /** XXX handle drain efd, too */ |
| |
| if (c->extended_usage == CHAN_EXTENDED_WRITE) |
| return channel_handle_efd_write(ssh, c, readset, writeset); |
| else if (c->extended_usage == CHAN_EXTENDED_READ || |
| c->extended_usage == CHAN_EXTENDED_IGNORE) |
| return channel_handle_efd_read(ssh, c, readset, writeset); |
| |
| return 1; |
| } |
| |
| static int |
| channel_check_window(struct ssh *ssh, Channel *c) |
| { |
| int r; |
| |
| 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) { |
| if (!c->have_remote_id) |
| fatal(":%s: channel %d: no remote id", |
| __func__, c->self); |
| if ((r = sshpkt_start(ssh, |
| SSH2_MSG_CHANNEL_WINDOW_ADJUST)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->local_consumed)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) { |
| fatal("%s: channel %i: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| 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(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| channel_handle_rfd(ssh, c, readset, writeset); |
| channel_handle_wfd(ssh, c, readset, writeset); |
| channel_handle_efd(ssh, c, readset, writeset); |
| channel_check_window(ssh, c); |
| } |
| |
| static u_int |
| read_mux(struct ssh *ssh, Channel *c, u_int need) |
| { |
| char buf[CHAN_RBUF]; |
| ssize_t len; |
| u_int rlen; |
| int r; |
| |
| if (sshbuf_len(c->input) < need) { |
| rlen = need - sshbuf_len(c->input); |
| len = read(c->rfd, buf, MINIMUM(rlen, CHAN_RBUF)); |
| if (len < 0 && (errno == EINTR || errno == EAGAIN)) |
| return sshbuf_len(c->input); |
| if (len <= 0) { |
| debug2("channel %d: ctl read<=0 rfd %d len %zd", |
| c->self, c->rfd, len); |
| chan_read_failed(ssh, c); |
| return 0; |
| } else if ((r = sshbuf_put(c->input, buf, len)) != 0) { |
| fatal("%s: channel %d: append: %s", |
| __func__, c->self, ssh_err(r)); |
| } |
| } |
| return sshbuf_len(c->input); |
| } |
| |
| static void |
| channel_post_mux_client_read(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| u_int need; |
| |
| if (c->rfd == -1 || !FD_ISSET(c->rfd, readset)) |
| return; |
| if (c->istate != CHAN_INPUT_OPEN && c->istate != CHAN_INPUT_WAIT_DRAIN) |
| return; |
| if (c->mux_pause) |
| return; |
| |
| /* |
| * Don't not read past the precise end of packets to |
| * avoid disrupting fd passing. |
| */ |
| if (read_mux(ssh, c, 4) < 4) /* read header */ |
| return; |
| /* XXX sshbuf_peek_u32 */ |
| need = PEEK_U32(sshbuf_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(ssh, c); |
| return; |
| } |
| if (read_mux(ssh, c, need + 4) < need + 4) /* read body */ |
| return; |
| if (c->mux_rcb(ssh, c) != 0) { |
| debug("channel %d: mux_rcb failed", c->self); |
| chan_mark_dead(ssh, c); |
| return; |
| } |
| } |
| |
| static void |
| channel_post_mux_client_write(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| ssize_t len; |
| int r; |
| |
| if (c->wfd == -1 || !FD_ISSET(c->wfd, writeset) || |
| sshbuf_len(c->output) == 0) |
| return; |
| |
| len = write(c->wfd, sshbuf_ptr(c->output), sshbuf_len(c->output)); |
| if (len < 0 && (errno == EINTR || errno == EAGAIN)) |
| return; |
| if (len <= 0) { |
| chan_mark_dead(ssh, c); |
| return; |
| } |
| if ((r = sshbuf_consume(c->output, len)) != 0) |
| fatal("%s: channel %d: consume: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| |
| static void |
| channel_post_mux_client(struct ssh *ssh, Channel *c, |
| fd_set *readset, fd_set *writeset) |
| { |
| channel_post_mux_client_read(ssh, c, readset, writeset); |
| channel_post_mux_client_write(ssh, c, readset, writeset); |
| } |
| |
| static void |
| channel_post_mux_listener(struct ssh *ssh, 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)); |
| if (errno == EMFILE || errno == ENFILE) |
| c->notbefore = monotime() + 1; |
| 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(ssh, "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(ssh, nc); |
| /* mux state transitions must not elicit protocol messages */ |
| nc->flags |= CHAN_LOCAL; |
| } |
| |
| static void |
| channel_handler_init(struct ssh_channels *sc) |
| { |
| chan_fn **pre, **post; |
| |
| if ((pre = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*pre))) == NULL || |
| (post = calloc(SSH_CHANNEL_MAX_TYPE, sizeof(*post))) == NULL) |
| fatal("%s: allocation failed", __func__); |
| |
| pre[SSH_CHANNEL_OPEN] = &channel_pre_open; |
| pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; |
| pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; |
| pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; |
| pre[SSH_CHANNEL_UNIX_LISTENER] = &channel_pre_listener; |
| pre[SSH_CHANNEL_RUNIX_LISTENER] = &channel_pre_listener; |
| pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; |
| pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; |
| pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; |
| pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; |
| pre[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_pre_connecting; |
| pre[SSH_CHANNEL_MUX_LISTENER] = &channel_pre_listener; |
| pre[SSH_CHANNEL_MUX_CLIENT] = &channel_pre_mux_client; |
| |
| post[SSH_CHANNEL_OPEN] = &channel_post_open; |
| post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; |
| post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; |
| post[SSH_CHANNEL_UNIX_LISTENER] = &channel_post_port_listener; |
| post[SSH_CHANNEL_RUNIX_LISTENER] = &channel_post_port_listener; |
| post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; |
| post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; |
| post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; |
| post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; |
| post[SSH_CHANNEL_RDYNAMIC_FINISH] = &channel_post_connecting; |
| post[SSH_CHANNEL_MUX_LISTENER] = &channel_post_mux_listener; |
| post[SSH_CHANNEL_MUX_CLIENT] = &channel_post_mux_client; |
| |
| sc->channel_pre = pre; |
| sc->channel_post = post; |
| } |
| |
| /* gc dead channels */ |
| static void |
| channel_garbage_collect(struct ssh *ssh, Channel *c) |
| { |
| if (c == NULL) |
| return; |
| if (c->detach_user != NULL) { |
| if (!chan_is_dead(ssh, c, c->detach_close)) |
| return; |
| |
| debug2("channel %d: gc: notify user", c->self); |
| c->detach_user(ssh, 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(ssh, c, 1)) |
| return; |
| debug2("channel %d: garbage collecting", c->self); |
| channel_free(ssh, c); |
| } |
| |
| enum channel_table { CHAN_PRE, CHAN_POST }; |
| |
| static void |
| channel_handler(struct ssh *ssh, int table, |
| fd_set *readset, fd_set *writeset, time_t *unpause_secs) |
| { |
| struct ssh_channels *sc = ssh->chanctxt; |
| chan_fn **ftab = table == CHAN_PRE ? sc->channel_pre : sc->channel_post; |
| u_int i, oalloc; |
| Channel *c; |
| time_t now; |
| |
| now = monotime(); |
| if (unpause_secs != NULL) |
| *unpause_secs = 0; |
| for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { |
| c = sc->channels[i]; |
| if (c == NULL) |
| continue; |
| if (c->delayed) { |
| if (table == CHAN_PRE) |
| c->delayed = 0; |
| else |
| continue; |
| } |
| if (ftab[c->type] != NULL) { |
| /* |
| * Run handlers that are not paused. |
| */ |
| if (c->notbefore <= now) |
| (*ftab[c->type])(ssh, c, readset, writeset); |
| else if (unpause_secs != NULL) { |
| /* |
| * Collect the time that the earliest |
| * channel comes off pause. |
| */ |
| debug3("%s: chan %d: skip for %d more seconds", |
| __func__, c->self, |
| (int)(c->notbefore - now)); |
| if (*unpause_secs == 0 || |
| (c->notbefore - now) < *unpause_secs) |
| *unpause_secs = c->notbefore - now; |
| } |
| } |
| channel_garbage_collect(ssh, c); |
| } |
| if (unpause_secs != NULL && *unpause_secs != 0) |
| debug3("%s: first channel unpauses in %d seconds", |
| __func__, (int)*unpause_secs); |
| } |
| |
| /* |
| * Create sockets before allocating the select bitmasks. |
| * This is necessary for things that need to happen after reading |
| * the network-input but before channel_prepare_select(). |
| */ |
| static void |
| channel_before_prepare_select(struct ssh *ssh) |
| { |
| struct ssh_channels *sc = ssh->chanctxt; |
| Channel *c; |
| u_int i, oalloc; |
| |
| for (i = 0, oalloc = sc->channels_alloc; i < oalloc; i++) { |
| c = sc->channels[i]; |
| if (c == NULL) |
| continue; |
| if (c->type == SSH_CHANNEL_RDYNAMIC_OPEN) |
| channel_before_prepare_select_rdynamic(ssh, c); |
| } |
| } |
| |
| /* |
| * Allocate/update select bitmasks and add any bits relevant to channels in |
| * select bitmasks. |
| */ |
| void |
| channel_prepare_select(struct ssh *ssh, fd_set **readsetp, fd_set **writesetp, |
| int *maxfdp, u_int *nallocp, time_t *minwait_secs) |
| { |
| u_int n, sz, nfdset; |
| |
| channel_before_prepare_select(ssh); /* might update channel_max_fd */ |
| |
| n = MAXIMUM(*maxfdp, ssh->chanctxt->channel_max_fd); |
| |
| nfdset = howmany(n+1, NFDBITS); |
| /* Explicitly test here, because xrealloc isn't always called */ |
| if (nfdset && SIZE_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 = xreallocarray(*readsetp, nfdset, sizeof(fd_mask)); |
| *writesetp = xreallocarray(*writesetp, nfdset, sizeof(fd_mask)); |
| *nallocp = sz; |
| } |
| *maxfdp = n; |
| memset(*readsetp, 0, sz); |
| memset(*writesetp, 0, sz); |
| |
| if (!ssh_packet_is_rekeying(ssh)) |
| channel_handler(ssh, CHAN_PRE, *readsetp, *writesetp, |
| minwait_secs); |
| } |
| |
| /* |
| * After select, perform any appropriate operations for channels which have |
| * events pending. |
| */ |
| void |
| channel_after_select(struct ssh *ssh, fd_set *readset, fd_set *writeset) |
| { |
| channel_handler(ssh, CHAN_POST, readset, writeset, NULL); |
| } |
| |
| /* |
| * Enqueue data for channels with open or draining c->input. |
| */ |
| static void |
| channel_output_poll_input_open(struct ssh *ssh, Channel *c) |
| { |
| size_t len, plen; |
| const u_char *pkt; |
| int r; |
| |
| if ((len = sshbuf_len(c->input)) == 0) { |
| if (c->istate == CHAN_INPUT_WAIT_DRAIN) { |
| /* |
| * 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/(%zu)", |
| c->self, c->efd, sshbuf_len(c->extended)); |
| else |
| chan_ibuf_empty(ssh, c); |
| } |
| return; |
| } |
| |
| if (!c->have_remote_id) |
| fatal(":%s: channel %d: no remote id", __func__, c->self); |
| |
| if (c->datagram) { |
| /* Check datagram will fit; drop if not */ |
| if ((r = sshbuf_get_string_direct(c->input, &pkt, &plen)) != 0) |
| fatal("%s: channel %d: get datagram: %s", __func__, |
| c->self, ssh_err(r)); |
| /* |
| * XXX this does tail-drop on the datagram queue which is |
| * usually suboptimal compared to head-drop. Better to have |
| * backpressure at read time? (i.e. read + discard) |
| */ |
| if (plen > c->remote_window || plen > c->remote_maxpacket) { |
| debug("channel %d: datagram too big", c->self); |
| return; |
| } |
| /* Enqueue it */ |
| if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || |
| (r = sshpkt_put_string(ssh, pkt, plen)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) { |
| fatal("%s: channel %i: datagram: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| c->remote_window -= plen; |
| return; |
| } |
| |
| /* Enqueue packet for buffered data. */ |
| if (len > c->remote_window) |
| len = c->remote_window; |
| if (len > c->remote_maxpacket) |
| len = c->remote_maxpacket; |
| if (len == 0) |
| return; |
| if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_DATA)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || |
| (r = sshpkt_put_string(ssh, sshbuf_ptr(c->input), len)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) { |
| fatal("%s: channel %i: data: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| if ((r = sshbuf_consume(c->input, len)) != 0) |
| fatal("%s: channel %i: consume: %s", __func__, |
| c->self, ssh_err(r)); |
| c->remote_window -= len; |
| } |
| |
| /* |
| * Enqueue data for channels with open c->extended in read mode. |
| */ |
| static void |
| channel_output_poll_extended_read(struct ssh *ssh, Channel *c) |
| { |
| size_t len; |
| int r; |
| |
| if ((len = sshbuf_len(c->extended)) == 0) |
| return; |
| |
| debug2("channel %d: rwin %u elen %zu euse %d", c->self, |
| c->remote_window, sshbuf_len(c->extended), c->extended_usage); |
| if (len > c->remote_window) |
| len = c->remote_window; |
| if (len > c->remote_maxpacket) |
| len = c->remote_maxpacket; |
| if (len == 0) |
| return; |
| if (!c->have_remote_id) |
| fatal(":%s: channel %d: no remote id", __func__, c->self); |
| if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || |
| (r = sshpkt_put_u32(ssh, SSH2_EXTENDED_DATA_STDERR)) != 0 || |
| (r = sshpkt_put_string(ssh, sshbuf_ptr(c->extended), len)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) { |
| fatal("%s: channel %i: data: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| if ((r = sshbuf_consume(c->extended, len)) != 0) |
| fatal("%s: channel %i: consume: %s", __func__, |
| c->self, ssh_err(r)); |
| c->remote_window -= len; |
| debug2("channel %d: sent ext data %zu", c->self, len); |
| } |
| |
| /* If there is data to send to the connection, enqueue some of it now. */ |
| void |
| channel_output_poll(struct ssh *ssh) |
| { |
| struct ssh_channels *sc = ssh->chanctxt; |
| Channel *c; |
| u_int i; |
| |
| for (i = 0; i < sc->channels_alloc; i++) { |
| c = sc->channels[i]; |
| if (c == NULL) |
| continue; |
| |
| /* |
| * We are only interested in channels that can have buffered |
| * incoming data. |
| */ |
| if (c->type != SSH_CHANNEL_OPEN) |
| continue; |
| if ((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) |
| channel_output_poll_input_open(ssh, c); |
| /* Send extended data, i.e. stderr */ |
| if (!(c->flags & CHAN_EOF_SENT) && |
| c->extended_usage == CHAN_EXTENDED_READ) |
| channel_output_poll_extended_read(ssh, c); |
| } |
| } |
| |
| /* -- mux proxy support */ |
| |
| /* |
| * When multiplexing channel messages for mux clients we have to deal |
| * with downstream messages from the mux client and upstream messages |
| * from the ssh server: |
| * 1) Handling downstream messages is straightforward and happens |
| * in channel_proxy_downstream(): |
| * - We forward all messages (mostly) unmodified to the server. |
| * - However, in order to route messages from upstream to the correct |
| * downstream client, we have to replace the channel IDs used by the |
| * mux clients with a unique channel ID because the mux clients might |
| * use conflicting channel IDs. |
| * - so we inspect and change both SSH2_MSG_CHANNEL_OPEN and |
| * SSH2_MSG_CHANNEL_OPEN_CONFIRMATION messages, create a local |
| * SSH_CHANNEL_MUX_PROXY channel and replace the mux clients ID |
| * with the newly allocated channel ID. |
| * 2) Upstream messages are received by matching SSH_CHANNEL_MUX_PROXY |
| * channels and processed by channel_proxy_upstream(). The local channel ID |
| * is then translated back to the original mux client ID. |
| * 3) In both cases we need to keep track of matching SSH2_MSG_CHANNEL_CLOSE |
| * messages so we can clean up SSH_CHANNEL_MUX_PROXY channels. |
| * 4) The SSH_CHANNEL_MUX_PROXY channels also need to closed when the |
| * downstream mux client are removed. |
| * 5) Handling SSH2_MSG_CHANNEL_OPEN messages from the upstream server |
| * requires more work, because they are not addressed to a specific |
| * channel. E.g. client_request_forwarded_tcpip() needs to figure |
| * out whether the request is addressed to the local client or a |
| * specific downstream client based on the listen-address/port. |
| * 6) Agent and X11-Forwarding have a similar problem and are currently |
| * not supported as the matching session/channel cannot be identified |
| * easily. |
| */ |
| |
| /* |
| * receive packets from downstream mux clients: |
| * channel callback fired on read from mux client, creates |
| * SSH_CHANNEL_MUX_PROXY channels and translates channel IDs |
| * on channel creation. |
| */ |
| int |
| channel_proxy_downstream(struct ssh *ssh, Channel *downstream) |
| { |
| Channel *c = NULL; |
| struct sshbuf *original = NULL, *modified = NULL; |
| const u_char *cp; |
| char *ctype = NULL, *listen_host = NULL; |
| u_char type; |
| size_t have; |
| int ret = -1, r; |
| u_int id, remote_id, listen_port; |
| |
| /* sshbuf_dump(downstream->input, stderr); */ |
| if ((r = sshbuf_get_string_direct(downstream->input, &cp, &have)) |
| != 0) { |
| error("%s: malformed message: %s", __func__, ssh_err(r)); |
| return -1; |
| } |
| if (have < 2) { |
| error("%s: short message", __func__); |
| return -1; |
| } |
| type = cp[1]; |
| /* skip padlen + type */ |
| cp += 2; |
| have -= 2; |
| if (ssh_packet_log_type(type)) |
| debug3("%s: channel %u: down->up: type %u", __func__, |
| downstream->self, type); |
| |
| switch (type) { |
| case SSH2_MSG_CHANNEL_OPEN: |
| if ((original = sshbuf_from(cp, have)) == NULL || |
| (modified = sshbuf_new()) == NULL) { |
| error("%s: alloc", __func__); |
| goto out; |
| } |
| if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0 || |
| (r = sshbuf_get_u32(original, &id)) != 0) { |
| error("%s: parse error %s", __func__, ssh_err(r)); |
| goto out; |
| } |
| c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, |
| -1, -1, -1, 0, 0, 0, ctype, 1); |
| c->mux_ctx = downstream; /* point to mux client */ |
| c->mux_downstream_id = id; /* original downstream id */ |
| if ((r = sshbuf_put_cstring(modified, ctype)) != 0 || |
| (r = sshbuf_put_u32(modified, c->self)) != 0 || |
| (r = sshbuf_putb(modified, original)) != 0) { |
| error("%s: compose error %s", __func__, ssh_err(r)); |
| channel_free(ssh, c); |
| goto out; |
| } |
| break; |
| case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: |
| /* |
| * Almost the same as SSH2_MSG_CHANNEL_OPEN, except then we |
| * need to parse 'remote_id' instead of 'ctype'. |
| */ |
| if ((original = sshbuf_from(cp, have)) == NULL || |
| (modified = sshbuf_new()) == NULL) { |
| error("%s: alloc", __func__); |
| goto out; |
| } |
| if ((r = sshbuf_get_u32(original, &remote_id)) != 0 || |
| (r = sshbuf_get_u32(original, &id)) != 0) { |
| error("%s: parse error %s", __func__, ssh_err(r)); |
| goto out; |
| } |
| c = channel_new(ssh, "mux proxy", SSH_CHANNEL_MUX_PROXY, |
| -1, -1, -1, 0, 0, 0, "mux-down-connect", 1); |
| c->mux_ctx = downstream; /* point to mux client */ |
| c->mux_downstream_id = id; |
| c->remote_id = remote_id; |
| c->have_remote_id = 1; |
| if ((r = sshbuf_put_u32(modified, remote_id)) != 0 || |
| (r = sshbuf_put_u32(modified, c->self)) != 0 || |
| (r = sshbuf_putb(modified, original)) != 0) { |
| error("%s: compose error %s", __func__, ssh_err(r)); |
| channel_free(ssh, c); |
| goto out; |
| } |
| break; |
| case SSH2_MSG_GLOBAL_REQUEST: |
| if ((original = sshbuf_from(cp, have)) == NULL) { |
| error("%s: alloc", __func__); |
| goto out; |
| } |
| if ((r = sshbuf_get_cstring(original, &ctype, NULL)) != 0) { |
| error("%s: parse error %s", __func__, ssh_err(r)); |
| goto out; |
| } |
| if (strcmp(ctype, "tcpip-forward") != 0) { |
| error("%s: unsupported request %s", __func__, ctype); |
| goto out; |
| } |
| if ((r = sshbuf_get_u8(original, NULL)) != 0 || |
| (r = sshbuf_get_cstring(original, &listen_host, NULL)) != 0 || |
| (r = sshbuf_get_u32(original, &listen_port)) != 0) { |
| error("%s: parse error %s", __func__, ssh_err(r)); |
| goto out; |
| } |
| if (listen_port > 65535) { |
| error("%s: tcpip-forward for %s: bad port %u", |
| __func__, listen_host, listen_port); |
| goto out; |
| } |
| /* Record that connection to this host/port is permitted. */ |
| permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, "<mux>", -1, |
| listen_host, NULL, (int)listen_port, downstream); |
| listen_host = NULL; |
| break; |
| case SSH2_MSG_CHANNEL_CLOSE: |
| if (have < 4) |
| break; |
| remote_id = PEEK_U32(cp); |
| if ((c = channel_by_remote_id(ssh, remote_id)) != NULL) { |
| if (c->flags & CHAN_CLOSE_RCVD) |
| channel_free(ssh, c); |
| else |
| c->flags |= CHAN_CLOSE_SENT; |
| } |
| break; |
| } |
| if (modified) { |
| if ((r = sshpkt_start(ssh, type)) != 0 || |
| (r = sshpkt_putb(ssh, modified)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) { |
| error("%s: send %s", __func__, ssh_err(r)); |
| goto out; |
| } |
| } else { |
| if ((r = sshpkt_start(ssh, type)) != 0 || |
| (r = sshpkt_put(ssh, cp, have)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) { |
| error("%s: send %s", __func__, ssh_err(r)); |
| goto out; |
| } |
| } |
| ret = 0; |
| out: |
| free(ctype); |
| free(listen_host); |
| sshbuf_free(original); |
| sshbuf_free(modified); |
| return ret; |
| } |
| |
| /* |
| * receive packets from upstream server and de-multiplex packets |
| * to correct downstream: |
| * implemented as a helper for channel input handlers, |
| * replaces local (proxy) channel ID with downstream channel ID. |
| */ |
| int |
| channel_proxy_upstream(Channel *c, int type, u_int32_t seq, struct ssh *ssh) |
| { |
| struct sshbuf *b = NULL; |
| Channel *downstream; |
| const u_char *cp = NULL; |
| size_t len; |
| int r; |
| |
| /* |
| * When receiving packets from the peer we need to check whether we |
| * need to forward the packets to the mux client. In this case we |
| * restore the original channel id and keep track of CLOSE messages, |
| * so we can cleanup the channel. |
| */ |
| if (c == NULL || c->type != SSH_CHANNEL_MUX_PROXY) |
| return 0; |
| if ((downstream = c->mux_ctx) == NULL) |
| return 0; |
| switch (type) { |
| case SSH2_MSG_CHANNEL_CLOSE: |
| case SSH2_MSG_CHANNEL_DATA: |
| case SSH2_MSG_CHANNEL_EOF: |
| case SSH2_MSG_CHANNEL_EXTENDED_DATA: |
| case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: |
| case SSH2_MSG_CHANNEL_OPEN_FAILURE: |
| case SSH2_MSG_CHANNEL_WINDOW_ADJUST: |
| case SSH2_MSG_CHANNEL_SUCCESS: |
| case SSH2_MSG_CHANNEL_FAILURE: |
| case SSH2_MSG_CHANNEL_REQUEST: |
| break; |
| default: |
| debug2("%s: channel %u: unsupported type %u", __func__, |
| c->self, type); |
| return 0; |
| } |
| if ((b = sshbuf_new()) == NULL) { |
| error("%s: alloc reply", __func__); |
| goto out; |
| } |
| /* get remaining payload (after id) */ |
| cp = sshpkt_ptr(ssh, &len); |
| if (cp == NULL) { |
| error("%s: no packet", __func__); |
| goto out; |
| } |
| /* translate id and send to muxclient */ |
| if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ |
| (r = sshbuf_put_u8(b, type)) != 0 || |
| (r = sshbuf_put_u32(b, c->mux_downstream_id)) != 0 || |
| (r = sshbuf_put(b, cp, len)) != 0 || |
| (r = sshbuf_put_stringb(downstream->output, b)) != 0) { |
| error("%s: compose for muxclient %s", __func__, ssh_err(r)); |
| goto out; |
| } |
| /* sshbuf_dump(b, stderr); */ |
| if (ssh_packet_log_type(type)) |
| debug3("%s: channel %u: up->down: type %u", __func__, c->self, |
| type); |
| out: |
| /* update state */ |
| switch (type) { |
| case SSH2_MSG_CHANNEL_OPEN_CONFIRMATION: |
| /* record remote_id for SSH2_MSG_CHANNEL_CLOSE */ |
| if (cp && len > 4) { |
| c->remote_id = PEEK_U32(cp); |
| c->have_remote_id = 1; |
| } |
| break; |
| case SSH2_MSG_CHANNEL_CLOSE: |
| if (c->flags & CHAN_CLOSE_SENT) |
| channel_free(ssh, c); |
| else |
| c->flags |= CHAN_CLOSE_RCVD; |
| break; |
| } |
| sshbuf_free(b); |
| return 1; |
| } |
| |
| /* -- protocol input */ |
| |
| /* Parse a channel ID from the current packet */ |
| static int |
| channel_parse_id(struct ssh *ssh, const char *where, const char *what) |
| { |
| u_int32_t id; |
| int r; |
| |
| if ((r = sshpkt_get_u32(ssh, &id)) != 0) { |
| error("%s: parse id: %s", where, ssh_err(r)); |
| ssh_packet_disconnect(ssh, "Invalid %s message", what); |
| } |
| if (id > INT_MAX) { |
| error("%s: bad channel id %u: %s", where, id, ssh_err(r)); |
| ssh_packet_disconnect(ssh, "Invalid %s channel id", what); |
| } |
| return (int)id; |
| } |
| |
| /* Lookup a channel from an ID in the current packet */ |
| static Channel * |
| channel_from_packet_id(struct ssh *ssh, const char *where, const char *what) |
| { |
| int id = channel_parse_id(ssh, where, what); |
| Channel *c; |
| |
| if ((c = channel_lookup(ssh, id)) == NULL) { |
| ssh_packet_disconnect(ssh, |
| "%s packet referred to nonexistent channel %d", what, id); |
| } |
| return c; |
| } |
| |
| int |
| channel_input_data(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| const u_char *data; |
| size_t data_len, win_len; |
| Channel *c = channel_from_packet_id(ssh, __func__, "data"); |
| int r; |
| |
| if (channel_proxy_upstream(c, type, seq, ssh)) |
| return 0; |
| |
| /* Ignore any data for non-open channels (might happen on close) */ |
| if (c->type != SSH_CHANNEL_OPEN && |
| c->type != SSH_CHANNEL_RDYNAMIC_OPEN && |
| c->type != SSH_CHANNEL_RDYNAMIC_FINISH && |
| c->type != SSH_CHANNEL_X11_OPEN) |
| return 0; |
| |
| /* Get the data. */ |
| if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || |
| (r = sshpkt_get_end(ssh)) != 0) |
| fatal("%s: channel %d: get data: %s", __func__, |
| c->self, ssh_err(r)); |
| |
| win_len = data_len; |
| if (c->datagram) |
| win_len += 4; /* string length header */ |
| |
| /* |
| * The sending side reduces 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 (c->ostate != CHAN_OUTPUT_OPEN) { |
| c->local_window -= win_len; |
| c->local_consumed += win_len; |
| return 0; |
| } |
| |
| if (win_len > c->local_maxpacket) { |
| logit("channel %d: rcvd big packet %zu, maxpack %u", |
| c->self, win_len, c->local_maxpacket); |
| return 0; |
| } |
| if (win_len > c->local_window) { |
| logit("channel %d: rcvd too much data %zu, win %u", |
| c->self, win_len, c->local_window); |
| return 0; |
| } |
| c->local_window -= win_len; |
| |
| if (c->datagram) { |
| if ((r = sshbuf_put_string(c->output, data, data_len)) != 0) |
| fatal("%s: channel %d: append datagram: %s", |
| __func__, c->self, ssh_err(r)); |
| } else if ((r = sshbuf_put(c->output, data, data_len)) != 0) |
| fatal("%s: channel %d: append data: %s", |
| __func__, c->self, ssh_err(r)); |
| |
| return 0; |
| } |
| |
| int |
| channel_input_extended_data(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| const u_char *data; |
| size_t data_len; |
| u_int32_t tcode; |
| Channel *c = channel_from_packet_id(ssh, __func__, "extended data"); |
| int r; |
| |
| if (channel_proxy_upstream(c, type, seq, ssh)) |
| return 0; |
| if (c->type != SSH_CHANNEL_OPEN) { |
| logit("channel %d: ext data for non open", c->self); |
| return 0; |
| } |
| if (c->flags & CHAN_EOF_RCVD) { |
| if (datafellows & SSH_BUG_EXTEOF) |
| debug("channel %d: accepting ext data after eof", |
| c->self); |
| else |
| ssh_packet_disconnect(ssh, "Received extended_data " |
| "after EOF on channel %d.", c->self); |
| } |
| |
| if ((r = sshpkt_get_u32(ssh, &tcode)) != 0) { |
| error("%s: parse tcode: %s", __func__, ssh_err(r)); |
| ssh_packet_disconnect(ssh, "Invalid extended_data message"); |
| } |
| if (c->efd == -1 || |
| c->extended_usage != CHAN_EXTENDED_WRITE || |
| tcode != SSH2_EXTENDED_DATA_STDERR) { |
| logit("channel %d: bad ext data", c->self); |
| return 0; |
| } |
| if ((r = sshpkt_get_string_direct(ssh, &data, &data_len)) != 0 || |
| (r = sshpkt_get_end(ssh)) != 0) { |
| error("%s: parse data: %s", __func__, ssh_err(r)); |
| ssh_packet_disconnect(ssh, "Invalid extended_data message"); |
| } |
| |
| if (data_len > c->local_window) { |
| logit("channel %d: rcvd too much extended_data %zu, win %u", |
| c->self, data_len, c->local_window); |
| return 0; |
| } |
| debug2("channel %d: rcvd ext data %zu", c->self, data_len); |
| /* XXX sshpkt_getb? */ |
| if ((r = sshbuf_put(c->extended, data, data_len)) != 0) |
| error("%s: append: %s", __func__, ssh_err(r)); |
| c->local_window -= data_len; |
| return 0; |
| } |
| |
| int |
| channel_input_ieof(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| Channel *c = channel_from_packet_id(ssh, __func__, "ieof"); |
| int r; |
| |
| if ((r = sshpkt_get_end(ssh)) != 0) { |
| error("%s: parse data: %s", __func__, ssh_err(r)); |
| ssh_packet_disconnect(ssh, "Invalid ieof message"); |
| } |
| |
| if (channel_proxy_upstream(c, type, seq, ssh)) |
| return 0; |
| chan_rcvd_ieof(ssh, 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 (sshbuf_len(c->input) == 0) |
| chan_ibuf_empty(ssh, c); |
| } |
| return 0; |
| } |
| |
| int |
| channel_input_oclose(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| Channel *c = channel_from_packet_id(ssh, __func__, "oclose"); |
| int r; |
| |
| if (channel_proxy_upstream(c, type, seq, ssh)) |
| return 0; |
| if ((r = sshpkt_get_end(ssh)) != 0) { |
| error("%s: parse data: %s", __func__, ssh_err(r)); |
| ssh_packet_disconnect(ssh, "Invalid oclose message"); |
| } |
| chan_rcvd_oclose(ssh, c); |
| return 0; |
| } |
| |
| int |
| channel_input_open_confirmation(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| Channel *c = channel_from_packet_id(ssh, __func__, "open confirmation"); |
| u_int32_t remote_window, remote_maxpacket; |
| int r; |
| |
| if (channel_proxy_upstream(c, type, seq, ssh)) |
| return 0; |
| if (c->type != SSH_CHANNEL_OPENING) |
| ssh_packet_disconnect(ssh, "Received open confirmation for " |
| "non-opening channel %d.", c->self); |
| /* |
| * Record the remote channel number and mark that the channel |
| * is now open. |
| */ |
| if ((r = sshpkt_get_u32(ssh, &c->remote_id)) != 0 || |
| (r = sshpkt_get_u32(ssh, &remote_window)) != 0 || |
| (r = sshpkt_get_u32(ssh, &remote_maxpacket)) != 0 || |
| (r = sshpkt_get_end(ssh)) != 0) { |
| error("%s: window/maxpacket: %s", __func__, ssh_err(r)); |
| ssh_packet_disconnect(ssh, "Invalid open confirmation message"); |
| } |
| |
| c->have_remote_id = 1; |
| c->remote_window = remote_window; |
| c->remote_maxpacket = remote_maxpacket; |
| c->type = SSH_CHANNEL_OPEN; |
| if (c->open_confirm) { |
| debug2("%s: channel %d: callback start", __func__, c->self); |
| c->open_confirm(ssh, c->self, 1, c->open_confirm_ctx); |
| debug2("%s: channel %d: callback done", __func__, c->self); |
| } |
| debug2("channel %d: open confirm rwindow %u rmax %u", c->self, |
| c->remote_window, c->remote_maxpacket); |
| return 0; |
| } |
| |
| 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"; |
| } |
| |
| int |
| channel_input_open_failure(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| Channel *c = channel_from_packet_id(ssh, __func__, "open failure"); |
| u_int32_t reason; |
| char *msg = NULL; |
| int r; |
| |
| if (channel_proxy_upstream(c, type, seq, ssh)) |
| return 0; |
| if (c->type != SSH_CHANNEL_OPENING) |
| ssh_packet_disconnect(ssh, "Received open failure for " |
| "non-opening channel %d.", c->self); |
| if ((r = sshpkt_get_u32(ssh, &reason)) != 0) { |
| error("%s: reason: %s", __func__, ssh_err(r)); |
| ssh_packet_disconnect(ssh, "Invalid open failure message"); |
| } |
| /* skip language */ |
| if ((r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || |
| (r = sshpkt_get_string_direct(ssh, NULL, NULL)) != 0 || |
| (r = sshpkt_get_end(ssh)) != 0) { |
| error("%s: message/lang: %s", __func__, ssh_err(r)); |
| ssh_packet_disconnect(ssh, "Invalid open failure message"); |
| } |
| logit("channel %d: open failed: %s%s%s", c->self, |
| reason2txt(reason), msg ? ": ": "", msg ? msg : ""); |
| free(msg); |
| if (c->open_confirm) { |
| debug2("%s: channel %d: callback start", __func__, c->self); |
| c->open_confirm(ssh, c->self, 0, c->open_confirm_ctx); |
| debug2("%s: channel %d: callback done", __func__, c->self); |
| } |
| /* Schedule the channel for cleanup/deletion. */ |
| chan_mark_dead(ssh, c); |
| return 0; |
| } |
| |
| int |
| channel_input_window_adjust(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| int id = channel_parse_id(ssh, __func__, "window adjust"); |
| Channel *c; |
| u_int32_t adjust; |
| u_int new_rwin; |
| int r; |
| |
| if ((c = channel_lookup(ssh, id)) == NULL) { |
| logit("Received window adjust for non-open channel %d.", id); |
| return 0; |
| } |
| |
| if (channel_proxy_upstream(c, type, seq, ssh)) |
| return 0; |
| if ((r = sshpkt_get_u32(ssh, &adjust)) != 0 || |
| (r = sshpkt_get_end(ssh)) != 0) { |
| error("%s: adjust: %s", __func__, ssh_err(r)); |
| ssh_packet_disconnect(ssh, "Invalid window adjust message"); |
| } |
| debug2("channel %d: rcvd adjust %u", c->self, adjust); |
| if ((new_rwin = c->remote_window + adjust) < c->remote_window) { |
| fatal("channel %d: adjust %u overflows remote window %u", |
| c->self, adjust, c->remote_window); |
| } |
| c->remote_window = new_rwin; |
| return 0; |
| } |
| |
| int |
| channel_input_status_confirm(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| int id = channel_parse_id(ssh, __func__, "status confirm"); |
| Channel *c; |
| struct channel_confirm *cc; |
| int r; |
| |
| /* Reset keepalive timeout */ |
| ssh_packet_set_alive_timeouts(ssh, 0); |
| |
| debug2("%s: type %d id %d", __func__, type, id); |
| |
| if ((c = channel_lookup(ssh, id)) == NULL) { |
| logit("%s: %d: unknown", __func__, id); |
| return 0; |
| } |
| if (channel_proxy_upstream(c, type, seq, ssh)) |
| return 0; |
| if ((r = sshpkt_get_end(ssh)) != 0) |
| ssh_packet_disconnect(ssh, "Invalid status confirm message"); |
| if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) |
| return 0; |
| cc->cb(ssh, type, c, cc->ctx); |
| TAILQ_REMOVE(&c->status_confirms, cc, entry); |
| explicit_bzero(cc, sizeof(*cc)); |
| free(cc); |
| return 0; |
| } |
| |
| /* -- tcp forwarding */ |
| |
| void |
| channel_set_af(struct ssh *ssh, int af) |
| { |
| ssh->chanctxt->IPv4or6 = af; |
| } |
| |
| |
| /* |
| * Determine whether or not a port forward listens to loopback, the |
| * 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 |
| * "127.0.0.1" / "::1" -> accepted even if gateway_ports isn't set |
| */ |
| static const char * |
| channel_fwd_bind_addr(struct ssh *ssh, const char *listen_addr, int *wildcardp, |
| int is_client, struct ForwardOptions *fwd_opts) |
| { |
| const char *addr = NULL; |
| int wildcard = 0; |
| |
| if (listen_addr == NULL) { |
| /* No address specified: default to gateway_ports setting */ |
| if (fwd_opts->gateway_ports) |
| wildcard = 1; |
| } else if (fwd_opts->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 && fwd_opts->gateway_ports == 1)) { |
| wildcard = 1; |
| /* |
| * Notify client if they requested a specific listen |
| * address and it was overridden. |
| */ |
| if (*listen_addr != '\0' && |
| strcmp(listen_addr, "0.0.0.0") != 0 && |
| strcmp(listen_addr, "*") != 0) { |
| ssh_packet_send_debug(ssh, |
| "Forwarding listen address " |
| "\"%s\" overridden by server " |
| "GatewayPorts", listen_addr); |
| } |
| } else if (strcmp(listen_addr, "localhost") != 0 || |
| strcmp(listen_addr, "127.0.0.1") == 0 || |
| strcmp(listen_addr, "::1") == 0) { |
| /* Accept localhost address when GatewayPorts=yes */ |
| addr = listen_addr; |
| } |
| } else if (strcmp(listen_addr, "127.0.0.1") == 0 || |
| strcmp(listen_addr, "::1") == 0) { |
| /* |
| * If a specific IPv4/IPv6 localhost address has been |
| * requested then accept it even if gateway_ports is in |
| * effect. This allows the client to prefer IPv4 or IPv6. |
| */ |
| addr = listen_addr; |
| } |
| if (wildcardp != NULL) |
| *wildcardp = wildcard; |
| return addr; |
| } |
| |
| static int |
| channel_setup_fwd_listener_tcpip(struct ssh *ssh, int type, |
| struct Forward *fwd, int *allocated_listen_port, |
| struct ForwardOptions *fwd_opts) |
| { |
| 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; |
| |
| is_client = (type == SSH_CHANNEL_PORT_LISTENER); |
| |
| if (is_client && fwd->connect_path != NULL) { |
| host = fwd->connect_path; |
| } else { |
| host = (type == SSH_CHANNEL_RPORT_LISTENER) ? |
| fwd->listen_host : fwd->connect_host; |
| if (host == NULL) { |
| error("No forward host name."); |
| return 0; |
| } |
| if (strlen(host) >= NI_MAXHOST) { |
| error("Forward host name too long."); |
| return 0; |
| } |
| } |
| |
| /* Determine the bind address, cf. channel_fwd_bind_addr() comment */ |
| addr = channel_fwd_bind_addr(ssh, fwd->listen_host, &wildcard, |
| is_client, fwd_opts); |
| debug3("%s: type %d wildcard %d addr %s", __func__, |
| 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 = ssh->chanctxt->IPv4or6; |
| hints.ai_flags = wildcard ? AI_PASSIVE : 0; |
| hints.ai_socktype = SOCK_STREAM; |
| snprintf(strport, sizeof strport, "%d", fwd->listen_port); |
| if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { |
| if (addr == NULL) { |
| /* This really shouldn't happen */ |
| ssh_packet_disconnect(ssh, "getaddrinfo: fatal error: %s", |
| ssh_gai_strerror(r)); |
| } else { |
| error("%s: getaddrinfo(%.64s): %s", __func__, 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 && |
| fwd->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("%s: getnameinfo failed", __func__); |
| 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 [%s]:%s: %.100s", ntop, strport, |
| strerror(errno)); |
| continue; |
| } |
| |
| set_reuseaddr(sock); |
| if (ai->ai_family == AF_INET6) |
| sock_set_v6only(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 if use ipv6 address is |
| * already bound |
| */ |
| if (!ai->ai_next) |
| error("bind [%s]:%s: %.100s", |
| ntop, strport, strerror(errno)); |
| else |
| verbose("bind [%s]:%s: %.100s", |
| ntop, strport, strerror(errno)); |
| |
| close(sock); |
| continue; |
| } |
| /* Start listening for connections on the socket. */ |
| if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { |
| error("listen: %.100s", strerror(errno)); |
| error("listen [%s]:%s: %.100s", ntop, strport, |
| strerror(errno)); |
| close(sock); |
| continue; |
| } |
| |
| /* |
| * fwd->listen_port == 0 requests a dynamically allocated port - |
| * record what we got. |
| */ |
| if (type == SSH_CHANNEL_RPORT_LISTENER && |
| fwd->listen_port == 0 && |
| allocated_listen_port != NULL && |
| *allocated_listen_port == 0) { |
| *allocated_listen_port = get_local_port(sock); |
| debug("Allocated listen port %d", |
| *allocated_listen_port); |
| } |
| |
| /* Allocate a channel number for the socket. */ |
| c = channel_new(ssh, "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 = fwd->connect_port; |
| c->listening_addr = addr == NULL ? NULL : xstrdup(addr); |
| if (fwd->listen_port == 0 && allocated_listen_port != NULL && |
| !(datafellows & SSH_BUG_DYNAMIC_RPORT)) |
| c->listening_port = *allocated_listen_port; |
| else |
| c->listening_port = fwd->listen_port; |
| success = 1; |
| } |
| if (success == 0) |
| error("%s: cannot listen to port: %d", __func__, |
| fwd->listen_port); |
| freeaddrinfo(aitop); |
| return success; |
| } |
| |
| static int |
| channel_setup_fwd_listener_streamlocal(struct ssh *ssh, int type, |
| struct Forward *fwd, struct ForwardOptions *fwd_opts) |
| { |
| struct sockaddr_un sunaddr; |
| const char *path; |
| Channel *c; |
| int port, sock; |
| mode_t omask; |
| |
| switch (type) { |
| case SSH_CHANNEL_UNIX_LISTENER: |
| if (fwd->connect_path != NULL) { |
| if (strlen(fwd->connect_path) > sizeof(sunaddr.sun_path)) { |
| error("Local connecting path too long: %s", |
| fwd->connect_path); |
| return 0; |
| } |
| path = fwd->connect_path; |
| port = PORT_STREAMLOCAL; |
| } else { |
| if (fwd->connect_host == NULL) { |
| error("No forward host name."); |
| return 0; |
| } |
| if (strlen(fwd->connect_host) >= NI_MAXHOST) { |
| error("Forward host name too long."); |
| return 0; |
| } |
| path = fwd->connect_host; |
| port = fwd->connect_port; |
| } |
| break; |
| case SSH_CHANNEL_RUNIX_LISTENER: |
| path = fwd->listen_path; |
| port = PORT_STREAMLOCAL; |
| break; |
| default: |
| error("%s: unexpected channel type %d", __func__, type); |
| return 0; |
| } |
| |
| if (fwd->listen_path == NULL) { |
| error("No forward path name."); |
| return 0; |
| } |
| if (strlen(fwd->listen_path) > sizeof(sunaddr.sun_path)) { |
| error("Local listening path too long: %s", fwd->listen_path); |
| return 0; |
| } |
| |
| debug3("%s: type %d path %s", __func__, type, fwd->listen_path); |
| |
| /* Start a Unix domain listener. */ |
| omask = umask(fwd_opts->streamlocal_bind_mask); |
| sock = unix_listener(fwd->listen_path, SSH_LISTEN_BACKLOG, |
| fwd_opts->streamlocal_bind_unlink); |
| umask(omask); |
| if (sock < 0) |
| return 0; |
| |
| debug("Local forwarding listening on path %s.", fwd->listen_path); |
| |
| /* Allocate a channel number for the socket. */ |
| c = channel_new(ssh, "unix listener", type, sock, sock, -1, |
| CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, |
| 0, "unix listener", 1); |
| c->path = xstrdup(path); |
| c->host_port = port; |
| c->listening_port = PORT_STREAMLOCAL; |
| c->listening_addr = xstrdup(fwd->listen_path); |
| return 1; |
| } |
| |
| static int |
| channel_cancel_rport_listener_tcpip(struct ssh *ssh, |
| const char *host, u_short port) |
| { |
| u_int i; |
| int found = 0; |
| |
| for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { |
| Channel *c = ssh->chanctxt->channels[i]; |
| if (c == NULL || c->type != SSH_CHANNEL_RPORT_LISTENER) |
| continue; |
| if (strcmp(c->path, host) == 0 && c->listening_port == port) { |
| debug2("%s: close channel %d", __func__, i); |
| channel_free(ssh, c); |
| found = 1; |
| } |
| } |
| |
| return found; |
| } |
| |
| static int |
| channel_cancel_rport_listener_streamlocal(struct ssh *ssh, const char *path) |
| { |
| u_int i; |
| int found = 0; |
| |
| for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { |
| Channel *c = ssh->chanctxt->channels[i]; |
| if (c == NULL || c->type != SSH_CHANNEL_RUNIX_LISTENER) |
| continue; |
| if (c->path == NULL) |
| continue; |
| if (strcmp(c->path, path) == 0) { |
| debug2("%s: close channel %d", __func__, i); |
| channel_free(ssh, c); |
| found = 1; |
| } |
| } |
| |
| return found; |
| } |
| |
| int |
| channel_cancel_rport_listener(struct ssh *ssh, struct Forward *fwd) |
| { |
| if (fwd->listen_path != NULL) { |
| return channel_cancel_rport_listener_streamlocal(ssh, |
| fwd->listen_path); |
| } else { |
| return channel_cancel_rport_listener_tcpip(ssh, |
| fwd->listen_host, fwd->listen_port); |
| } |
| } |
| |
| static int |
| channel_cancel_lport_listener_tcpip(struct ssh *ssh, |
| const char *lhost, u_short lport, int cport, |
| struct ForwardOptions *fwd_opts) |
| { |
| u_int i; |
| int found = 0; |
| const char *addr = channel_fwd_bind_addr(ssh, lhost, NULL, 1, fwd_opts); |
| |
| for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { |
| Channel *c = ssh->chanctxt->channels[i]; |
| if (c == NULL || c->type != SSH_CHANNEL_PORT_LISTENER) |
| continue; |
| if (c->listening_port != lport) |
| continue; |
| if (cport == CHANNEL_CANCEL_PORT_STATIC) { |
| /* skip dynamic forwardings */ |
| if (c->host_port == 0) |
| continue; |
| } else { |
| if (c->host_port != cport) |
| continue; |
| } |
| if ((c->listening_addr == NULL && addr != NULL) || |
| (c->listening_addr != NULL && addr == NULL)) |
| continue; |
| if (addr == NULL || strcmp(c->listening_addr, addr) == 0) { |
| debug2("%s: close channel %d", __func__, i); |
| channel_free(ssh, c); |
| found = 1; |
| } |
| } |
| |
| return found; |
| } |
| |
| static int |
| channel_cancel_lport_listener_streamlocal(struct ssh *ssh, const char *path) |
| { |
| u_int i; |
| int found = 0; |
| |
| if (path == NULL) { |
| error("%s: no path specified.", __func__); |
| return 0; |
| } |
| |
| for (i = 0; i < ssh->chanctxt->channels_alloc; i++) { |
| Channel *c = ssh->chanctxt->channels[i]; |
| if (c == NULL || c->type != SSH_CHANNEL_UNIX_LISTENER) |
| continue; |
| if (c->listening_addr == NULL) |
| continue; |
| if (strcmp(c->listening_addr, path) == 0) { |
| debug2("%s: close channel %d", __func__, i); |
| channel_free(ssh, c); |
| found = 1; |
| } |
| } |
| |
| return found; |
| } |
| |
| int |
| channel_cancel_lport_listener(struct ssh *ssh, |
| struct Forward *fwd, int cport, struct ForwardOptions *fwd_opts) |
| { |
| if (fwd->listen_path != NULL) { |
| return channel_cancel_lport_listener_streamlocal(ssh, |
| fwd->listen_path); |
| } else { |
| return channel_cancel_lport_listener_tcpip(ssh, |
| fwd->listen_host, fwd->listen_port, cport, fwd_opts); |
| } |
| } |
| |
| /* protocol local port fwd, used by ssh */ |
| int |
| channel_setup_local_fwd_listener(struct ssh *ssh, |
| struct Forward *fwd, struct ForwardOptions *fwd_opts) |
| { |
| if (fwd->listen_path != NULL) { |
| return channel_setup_fwd_listener_streamlocal(ssh, |
| SSH_CHANNEL_UNIX_LISTENER, fwd, fwd_opts); |
| } else { |
| return channel_setup_fwd_listener_tcpip(ssh, |
| SSH_CHANNEL_PORT_LISTENER, fwd, NULL, fwd_opts); |
| } |
| } |
| |
| /* Matches a remote forwarding permission against a requested forwarding */ |
| static int |
| remote_open_match(struct permission *allowed_open, struct Forward *fwd) |
| { |
| int ret; |
| char *lhost; |
| |
| /* XXX add ACLs for streamlocal */ |
| if (fwd->listen_path != NULL) |
| return 1; |
| |
| if (fwd->listen_host == NULL || allowed_open->listen_host == NULL) |
| return 0; |
| |
| if (allowed_open->listen_port != FWD_PERMIT_ANY_PORT && |
| allowed_open->listen_port != fwd->listen_port) |
| return 0; |
| |
| /* Match hostnames case-insensitively */ |
| lhost = xstrdup(fwd->listen_host); |
| lowercase(lhost); |
| ret = match_pattern(lhost, allowed_open->listen_host); |
| free(lhost); |
| |
| return ret; |
| } |
| |
| /* Checks whether a requested remote forwarding is permitted */ |
| static int |
| check_rfwd_permission(struct ssh *ssh, struct Forward *fwd) |
| { |
| struct ssh_channels *sc = ssh->chanctxt; |
| struct permission_set *pset = &sc->remote_perms; |
| u_int i, permit, permit_adm = 1; |
| struct permission *perm; |
| |
| /* XXX apply GatewayPorts override before checking? */ |
| |
| permit = pset->all_permitted; |
| if (!permit) { |
| for (i = 0; i < pset->num_permitted_user; i++) { |
| perm = &pset->permitted_user[i]; |
| if (remote_open_match(perm, fwd)) { |
| permit = 1; |
| break; |
| } |
| } |
| } |
| |
| if (pset->num_permitted_admin > 0) { |
| permit_adm = 0; |
| for (i = 0; i < pset->num_permitted_admin; i++) { |
| perm = &pset->permitted_admin[i]; |
| if (remote_open_match(perm, fwd)) { |
| permit_adm = 1; |
| break; |
| } |
| } |
| } |
| |
| return permit && permit_adm; |
| } |
| |
| /* protocol v2 remote port fwd, used by sshd */ |
| int |
| channel_setup_remote_fwd_listener(struct ssh *ssh, struct Forward *fwd, |
| int *allocated_listen_port, struct ForwardOptions *fwd_opts) |
| { |
| if (!check_rfwd_permission(ssh, fwd)) { |
| ssh_packet_send_debug(ssh, "port forwarding refused"); |
| return 0; |
| } |
| if (fwd->listen_path != NULL) { |
| return channel_setup_fwd_listener_streamlocal(ssh, |
| SSH_CHANNEL_RUNIX_LISTENER, fwd, fwd_opts); |
| } else { |
| return channel_setup_fwd_listener_tcpip(ssh, |
| SSH_CHANNEL_RPORT_LISTENER, fwd, allocated_listen_port, |
| fwd_opts); |
| } |
| } |
| |
| /* |
| * Translate the requested rfwd listen host to something usable for |
| * this server. |
| */ |
| static const char * |
| channel_rfwd_bind_host(const char *listen_host) |
| { |
| if (listen_host == NULL) { |
| return "localhost"; |
| } else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) { |
| return ""; |
| } else |
| return listen_host; |
| } |
| |
| /* |
| * Initiate forwarding of connections to port "port" on remote host through |
| * the secure channel to host:port from local side. |
| * Returns handle (index) for updating the dynamic listen port with |
| * channel_update_permission(). |
| */ |
| int |
| channel_request_remote_forwarding(struct ssh *ssh, struct Forward *fwd) |
| { |
| int r, success = 0, idx = -1; |
| char *host_to_connect, *listen_host, *listen_path; |
| int port_to_connect, listen_port; |
| |
| /* Send the forward request to the remote side. */ |
| if (fwd->listen_path != NULL) { |
| if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || |
| (r = sshpkt_put_cstring(ssh, |
| "streamlocal-forward@openssh.com")) != 0 || |
| (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ |
| (r = sshpkt_put_cstring(ssh, fwd->listen_path)) != 0 || |
| (r = sshpkt_send(ssh)) != 0 || |
| (r = ssh_packet_write_wait(ssh)) != 0) |
| fatal("%s: request streamlocal: %s", |
| __func__, ssh_err(r)); |
| } else { |
| if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || |
| (r = sshpkt_put_cstring(ssh, "tcpip-forward")) != 0 || |
| (r = sshpkt_put_u8(ssh, 1)) != 0 || /* want reply */ |
| (r = sshpkt_put_cstring(ssh, |
| channel_rfwd_bind_host(fwd->listen_host))) != 0 || |
| (r = sshpkt_put_u32(ssh, fwd->listen_port)) != 0 || |
| (r = sshpkt_send(ssh)) != 0 || |
| (r = ssh_packet_write_wait(ssh)) != 0) |
| fatal("%s: request tcpip-forward: %s", |
| __func__, ssh_err(r)); |
| } |
| /* Assume that server accepts the request */ |
| success = 1; |
| if (success) { |
| /* Record that connection to this host/port is permitted. */ |
| host_to_connect = listen_host = listen_path = NULL; |
| port_to_connect = listen_port = 0; |
| if (fwd->connect_path != NULL) { |
| host_to_connect = xstrdup(fwd->connect_path); |
| port_to_connect = PORT_STREAMLOCAL; |
| } else { |
| host_to_connect = xstrdup(fwd->connect_host); |
| port_to_connect = fwd->connect_port; |
| } |
| if (fwd->listen_path != NULL) { |
| listen_path = xstrdup(fwd->listen_path); |
| listen_port = PORT_STREAMLOCAL; |
| } else { |
| if (fwd->listen_host != NULL) |
| listen_host = xstrdup(fwd->listen_host); |
| listen_port = fwd->listen_port; |
| } |
| idx = permission_set_add(ssh, FORWARD_USER, FORWARD_LOCAL, |
| host_to_connect, port_to_connect, |
| listen_host, listen_path, listen_port, NULL); |
| } |
| return idx; |
| } |
| |
| static int |
| open_match(struct permission *allowed_open, const char *requestedhost, |
| int requestedport) |
| { |
| if (allowed_open->host_to_connect == NULL) |
| return 0; |
| if (allowed_open->port_to_connect != FWD_PERMIT_ANY_PORT && |
| allowed_open->port_to_connect != requestedport) |
| return 0; |
| if (strcmp(allowed_open->host_to_connect, FWD_PERMIT_ANY_HOST) != 0 && |
| strcmp(allowed_open->host_to_connect, requestedhost) != 0) |
| return 0; |
| return 1; |
| } |
| |
| /* |
| * Note that in the listen host/port case |
| * we don't support FWD_PERMIT_ANY_PORT and |
| * need to translate between the configured-host (listen_host) |
| * and what we've sent to the remote server (channel_rfwd_bind_host) |
| */ |
| static int |
| open_listen_match_tcpip(struct permission *allowed_open, |
| const char *requestedhost, u_short requestedport, int translate) |
| { |
| const char *allowed_host; |
| |
| if (allowed_open->host_to_connect == NULL) |
| return 0; |
| if (allowed_open->listen_port != requestedport) |
| return 0; |
| if (!translate && allowed_open->listen_host == NULL && |
| requestedhost == NULL) |
| return 1; |
| allowed_host = translate ? |
| channel_rfwd_bind_host(allowed_open->listen_host) : |
| allowed_open->listen_host; |
| if (allowed_host == NULL || requestedhost == NULL || |
| strcmp(allowed_host, requestedhost) != 0) |
| return 0; |
| return 1; |
| } |
| |
| static int |
| open_listen_match_streamlocal(struct permission *allowed_open, |
| const char *requestedpath) |
| { |
| if (allowed_open->host_to_connect == NULL) |
| return 0; |
| if (allowed_open->listen_port != PORT_STREAMLOCAL) |
| return 0; |
| if (allowed_open->listen_path == NULL || |
| strcmp(allowed_open->listen_path, requestedpath) != 0) |
| return 0; |
| return 1; |
| } |
| |
| /* |
| * Request cancellation of remote forwarding of connection host:port from |
| * local side. |
| */ |
| static int |
| channel_request_rforward_cancel_tcpip(struct ssh *ssh, |
| const char *host, u_short port) |
| { |
| struct ssh_channels *sc = ssh->chanctxt; |
| struct permission_set *pset = &sc->local_perms; |
| int r; |
| u_int i; |
| struct permission *perm; |
| |
| for (i = 0; i < pset->num_permitted_user; i++) { |
| perm = &pset->permitted_user[i]; |
| if (open_listen_match_tcpip(perm, host, port, 0)) |
| break; |
| perm = NULL; |
| } |
| if (perm == NULL) { |
| debug("%s: requested forward not found", __func__); |
| return -1; |
| } |
| 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 || /* want reply */ |
| (r = sshpkt_put_cstring(ssh, channel_rfwd_bind_host(host))) != 0 || |
| (r = sshpkt_put_u32(ssh, port)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: send cancel: %s", __func__, ssh_err(r)); |
| |
| fwd_perm_clear(perm); /* unregister */ |
| |
| return 0; |
| } |
| |
| /* |
| * Request cancellation of remote forwarding of Unix domain socket |
| * path from local side. |
| */ |
| static int |
| channel_request_rforward_cancel_streamlocal(struct ssh *ssh, const char *path) |
| { |
| struct ssh_channels *sc = ssh->chanctxt; |
| struct permission_set *pset = &sc->local_perms; |
| int r; |
| u_int i; |
| struct permission *perm; |
| |
| for (i = 0; i < pset->num_permitted_user; i++) { |
| perm = &pset->permitted_user[i]; |
| if (open_listen_match_streamlocal(perm, path)) |
| break; |
| perm = NULL; |
| } |
| if (perm == NULL) { |
| debug("%s: requested forward not found", __func__); |
| return -1; |
| } |
| if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || |
| (r = sshpkt_put_cstring(ssh, |
| "cancel-streamlocal-forward@openssh.com")) != 0 || |
| (r = sshpkt_put_u8(ssh, 0)) != 0 || /* want reply */ |
| (r = sshpkt_put_cstring(ssh, path)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: send cancel: %s", __func__, ssh_err(r)); |
| |
| fwd_perm_clear(perm); /* unregister */ |
| |
| return 0; |
| } |
| |
| /* |
| * Request cancellation of remote forwarding of a connection from local side. |
| */ |
| int |
| channel_request_rforward_cancel(struct ssh *ssh, struct Forward *fwd) |
| { |
| if (fwd->listen_path != NULL) { |
| return channel_request_rforward_cancel_streamlocal(ssh, |
| fwd->listen_path); |
| } else { |
| return channel_request_rforward_cancel_tcpip(ssh, |
| fwd->listen_host, |
| fwd->listen_port ? fwd->listen_port : fwd->allocated_port); |
| } |
| } |
| |
| /* |
| * Permits opening to any host/port if permitted_user[] 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(struct ssh *ssh, int where) |
| { |
| struct permission_set *pset = permission_set_get(ssh, where); |
| |
| if (pset->num_permitted_user == 0) |
| pset->all_permitted = 1; |
| } |
| |
| /* |
| * Permit the specified host/port for forwarding. |
| */ |
| void |
| channel_add_permission(struct ssh *ssh, int who, int where, |
| char *host, int port) |
| { |
| int local = where == FORWARD_LOCAL; |
| struct permission_set *pset = permission_set_get(ssh, where); |
| |
| debug("allow %s forwarding to host %s port %d", |
| fwd_ident(who, where), host, port); |
| /* |
| * Remote forwards set listen_host/port, local forwards set |
| * host/port_to_connect. |
| */ |
| permission_set_add(ssh, who, where, |
| local ? host : 0, local ? port : 0, |
| local ? NULL : host, NULL, local ? 0 : port, NULL); |
| pset->all_permitted = 0; |
| } |
| |
| /* |
| * Administratively disable forwarding. |
| */ |
| void |
| channel_disable_admin(struct ssh *ssh, int where) |
| { |
| channel_clear_permission(ssh, FORWARD_ADM, where); |
| permission_set_add(ssh, FORWARD_ADM, where, |
| NULL, 0, NULL, NULL, 0, NULL); |
| } |
| |
| /* |
| * Clear a list of permitted opens. |
| */ |
| void |
| channel_clear_permission(struct ssh *ssh, int who, int where) |
| { |
| struct permission **permp; |
| u_int *npermp; |
| |
| permission_set_get_array(ssh, who, where, &permp, &npermp); |
| *permp = xrecallocarray(*permp, *npermp, 0, sizeof(**permp)); |
| *npermp = 0; |
| } |
| |
| /* |
| * Update the listen port for a dynamic remote forward, after |
| * the actual 'newport' has been allocated. If 'newport' < 0 is |
| * passed then they entry will be invalidated. |
| */ |
| void |
| channel_update_permission(struct ssh *ssh, int idx, int newport) |
| { |
| struct permission_set *pset = &ssh->chanctxt->local_perms; |
| |
| if (idx < 0 || (u_int)idx >= pset->num_permitted_user) { |
| debug("%s: index out of range: %d num_permitted_user %d", |
| __func__, idx, pset->num_permitted_user); |
| return; |
| } |
| debug("%s allowed port %d for forwarding to host %s port %d", |
| newport > 0 ? "Updating" : "Removing", |
| newport, |
| pset->permitted_user[idx].host_to_connect, |
| pset->permitted_user[idx].port_to_connect); |
| if (newport <= 0) |
| fwd_perm_clear(&pset->permitted_user[idx]); |
| else { |
| pset->permitted_user[idx].listen_port = |
| (datafellows & SSH_BUG_DYNAMIC_RPORT) ? 0 : newport; |
| } |
| } |
| |
| /* returns port number, FWD_PERMIT_ANY_PORT or -1 on error */ |
| int |
| permitopen_port(const char *p) |
| { |
| int port; |
| |
| if (strcmp(p, "*") == 0) |
| return FWD_PERMIT_ANY_PORT; |
| if ((port = a2port(p)) > 0) |
| return port; |
| return -1; |
| } |
| |
| /* Try to start non-blocking connect to next host in cctx list */ |
| static int |
| connect_next(struct channel_connect *cctx) |
| { |
| int sock, saved_errno; |
| struct sockaddr_un *sunaddr; |
| char ntop[NI_MAXHOST]; |
| char strport[MAXIMUM(NI_MAXSERV, sizeof(sunaddr->sun_path))]; |
| |
| for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { |
| switch (cctx->ai->ai_family) { |
| case AF_UNIX: |
| /* unix:pathname instead of host:port */ |
| sunaddr = (struct sockaddr_un *)cctx->ai->ai_addr; |
| strlcpy(ntop, "unix", sizeof(ntop)); |
| strlcpy(strport, sunaddr->sun_path, sizeof(strport)); |
| break; |
| case AF_INET: |
| case AF_INET6: |
| 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; |
| } |
| break; |
| default: |
| 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 */ |
| } |
| if (cctx->ai->ai_family != AF_UNIX) |
| set_nodelay(sock); |
| debug("connect_next: host %.100s ([%.100s]:%s) " |
| "in progress, fd=%d", cctx->host, ntop, strport, sock); |
| cctx->ai = cctx->ai->ai_next; |
| return sock; |
| } |
| return -1; |
| } |
| |
| static void |
| channel_connect_ctx_free(struct channel_connect *cctx) |
| { |
| free(cctx->host); |
| if (cctx->aitop) { |
| if (cctx->aitop->ai_family == AF_UNIX) |
| free(cctx->aitop); |
| else |
| freeaddrinfo(cctx->aitop); |
| } |
| memset(cctx, 0, sizeof(*cctx)); |
| } |
| |
| /* |
| * Return connecting socket to remote host:port or local socket path, |
| * passing back the failure reason if appropriate. |
| */ |
| static int |
| connect_to_helper(struct ssh *ssh, const char *name, int port, int socktype, |
| char *ctype, char *rname, struct channel_connect *cctx, |
| int *reason, const char **errmsg) |
| { |
| struct addrinfo hints; |
| int gaierr; |
| int sock = -1; |
| char strport[NI_MAXSERV]; |
| |
| if (port == PORT_STREAMLOCAL) { |
| struct sockaddr_un *sunaddr; |
| struct addrinfo *ai; |
| |
| if (strlen(name) > sizeof(sunaddr->sun_path)) { |
| error("%.100s: %.100s", name, strerror(ENAMETOOLONG)); |
| return -1; |
| } |
| |
| /* |
| * Fake up a struct addrinfo for AF_UNIX connections. |
| * channel_connect_ctx_free() must check ai_family |
| * and use free() not freeaddirinfo() for AF_UNIX. |
| */ |
| ai = xmalloc(sizeof(*ai) + sizeof(*sunaddr)); |
| memset(ai, 0, sizeof(*ai) + sizeof(*sunaddr)); |
| ai->ai_addr = (struct sockaddr *)(ai + 1); |
| ai->ai_addrlen = sizeof(*sunaddr); |
| ai->ai_family = AF_UNIX; |
| ai->ai_socktype = socktype; |
| ai->ai_protocol = PF_UNSPEC; |
| sunaddr = (struct sockaddr_un *)ai->ai_addr; |
| sunaddr->sun_family = AF_UNIX; |
| strlcpy(sunaddr->sun_path, name, sizeof(sunaddr->sun_path)); |
| cctx->aitop = ai; |
| } else { |
| memset(&hints, 0, sizeof(hints)); |
| hints.ai_family = ssh->chanctxt->IPv4or6; |
| hints.ai_socktype = socktype; |
| snprintf(strport, sizeof strport, "%d", port); |
| if ((gaierr = getaddrinfo(name, strport, &hints, &cctx->aitop)) |
| != 0) { |
| if (errmsg != NULL) |
| *errmsg = ssh_gai_strerror(gaierr); |
| if (reason != NULL) |
| *reason = SSH2_OPEN_CONNECT_FAILED; |
| error("connect_to %.100s: unknown host (%s)", name, |
| ssh_gai_strerror(gaierr)); |
| return -1; |
| } |
| } |
| |
| cctx->host = xstrdup(name); |
| cctx->port = port; |
| cctx->ai = cctx->aitop; |
| |
| if ((sock = connect_next(cctx)) == -1) { |
| error("connect to %.100s port %d failed: %s", |
| name, port, strerror(errno)); |
| return -1; |
| } |
| |
| return sock; |
| } |
| |
| /* Return CONNECTING channel to remote host:port or local socket path */ |
| static Channel * |
| connect_to(struct ssh *ssh, const char *host, int port, |
| char *ctype, char *rname) |
| { |
| struct channel_connect cctx; |
| Channel *c; |
| int sock; |
| |
| memset(&cctx, 0, sizeof(cctx)); |
| sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, |
| &cctx, NULL, NULL); |
| if (sock == -1) { |
| channel_connect_ctx_free(&cctx); |
| return NULL; |
| } |
| c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, |
| CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); |
| c->host_port = port; |
| c->path = xstrdup(host); |
| c->connect_ctx = cctx; |
| |
| return c; |
| } |
| |
| /* |
| * returns either the newly connected channel or the downstream channel |
| * that needs to deal with this connection. |
| */ |
| Channel * |
| channel_connect_by_listen_address(struct ssh *ssh, const char *listen_host, |
| u_short listen_port, char *ctype, char *rname) |
| { |
| struct ssh_channels *sc = ssh->chanctxt; |
| struct permission_set *pset = &sc->local_perms; |
| u_int i; |
| struct permission *perm; |
| |
| for (i = 0; i < pset->num_permitted_user; i++) { |
| perm = &pset->permitted_user[i]; |
| if (open_listen_match_tcpip(perm, |
| listen_host, listen_port, 1)) { |
| if (perm->downstream) |
| return perm->downstream; |
| if (perm->port_to_connect == 0) |
| return rdynamic_connect_prepare(ssh, |
| ctype, rname); |
| return connect_to(ssh, |
| perm->host_to_connect, perm->port_to_connect, |
| ctype, rname); |
| } |
| } |
| error("WARNING: Server requests forwarding for unknown listen_port %d", |
| listen_port); |
| return NULL; |
| } |
| |
| Channel * |
| channel_connect_by_listen_path(struct ssh *ssh, const char *path, |
| char *ctype, char *rname) |
| { |
| struct ssh_channels *sc = ssh->chanctxt; |
| struct permission_set *pset = &sc->local_perms; |
| u_int i; |
| struct permission *perm; |
| |
| for (i = 0; i < pset->num_permitted_user; i++) { |
| perm = &pset->permitted_user[i]; |
| if (open_listen_match_streamlocal(perm, path)) { |
| return connect_to(ssh, |
| perm->host_to_connect, perm->port_to_connect, |
| ctype, rname); |
| } |
| } |
| error("WARNING: Server requests forwarding for unknown path %.100s", |
| path); |
| return NULL; |
| } |
| |
| /* Check if connecting to that port is permitted and connect. */ |
| Channel * |
| channel_connect_to_port(struct ssh *ssh, const char *host, u_short port, |
| char *ctype, char *rname, int *reason, const char **errmsg) |
| { |
| struct ssh_channels *sc = ssh->chanctxt; |
| struct permission_set *pset = &sc->local_perms; |
| struct channel_connect cctx; |
| Channel *c; |
| u_int i, permit, permit_adm = 1; |
| int sock; |
| struct permission *perm; |
| |
| permit = pset->all_permitted; |
| if (!permit) { |
| for (i = 0; i < pset->num_permitted_user; i++) { |
| perm = &pset->permitted_user[i]; |
| if (open_match(perm, host, port)) { |
| permit = 1; |
| break; |
| } |
| } |
| } |
| |
| if (pset->num_permitted_admin > 0) { |
| permit_adm = 0; |
| for (i = 0; i < pset->num_permitted_admin; i++) { |
| perm = &pset->permitted_admin[i]; |
| if (open_match(perm, host, port)) { |
| permit_adm = 1; |
| break; |
| } |
| } |
| } |
| |
| if (!permit || !permit_adm) { |
| logit("Received request to connect to host %.100s port %d, " |
| "but the request was denied.", host, port); |
| if (reason != NULL) |
| *reason = SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED; |
| return NULL; |
| } |
| |
| memset(&cctx, 0, sizeof(cctx)); |
| sock = connect_to_helper(ssh, host, port, SOCK_STREAM, ctype, rname, |
| &cctx, reason, errmsg); |
| if (sock == -1) { |
| channel_connect_ctx_free(&cctx); |
| return NULL; |
| } |
| |
| c = channel_new(ssh, ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, |
| CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); |
| c->host_port = port; |
| c->path = xstrdup(host); |
| c->connect_ctx = cctx; |
| |
| return c; |
| } |
| |
| /* Check if connecting to that path is permitted and connect. */ |
| Channel * |
| channel_connect_to_path(struct ssh *ssh, const char *path, |
| char *ctype, char *rname) |
| { |
| struct ssh_channels *sc = ssh->chanctxt; |
| struct permission_set *pset = &sc->local_perms; |
| u_int i, permit, permit_adm = 1; |
| struct permission *perm; |
| |
| permit = pset->all_permitted; |
| if (!permit) { |
| for (i = 0; i < pset->num_permitted_user; i++) { |
| perm = &pset->permitted_user[i]; |
| if (open_match(perm, path, PORT_STREAMLOCAL)) { |
| permit = 1; |
| break; |
| } |
| } |
| } |
| |
| if (pset->num_permitted_admin > 0) { |
| permit_adm = 0; |
| for (i = 0; i < pset->num_permitted_admin; i++) { |
| perm = &pset->permitted_admin[i]; |
| if (open_match(perm, path, PORT_STREAMLOCAL)) { |
| permit_adm = 1; |
| break; |
| } |
| } |
| } |
| |
| if (!permit || !permit_adm) { |
| logit("Received request to connect to path %.100s, " |
| "but the request was denied.", path); |
| return NULL; |
| } |
| return connect_to(ssh, path, PORT_STREAMLOCAL, ctype, rname); |
| } |
| |
| void |
| channel_send_window_changes(struct ssh *ssh) |
| { |
| struct ssh_channels *sc = ssh->chanctxt; |
| struct winsize ws; |
| int r; |
| u_int i; |
| |
| for (i = 0; i < sc->channels_alloc; i++) { |
| if (sc->channels[i] == NULL || !sc->channels[i]->client_tty || |
| sc->channels[i]->type != SSH_CHANNEL_OPEN) |
| continue; |
| if (ioctl(sc->channels[i]->rfd, TIOCGWINSZ, &ws) < 0) |
| continue; |
| channel_request_start(ssh, i, "window-change", 0); |
| if ((r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || |
| (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || |
| (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || |
| (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: channel %u: send window-change: %s", |
| __func__, i, ssh_err(r)); |
| } |
| } |
| |
| /* Return RDYNAMIC_OPEN channel: channel allows SOCKS, but is not connected */ |
| static Channel * |
| rdynamic_connect_prepare(struct ssh *ssh, char *ctype, char *rname) |
| { |
| Channel *c; |
| int r; |
| |
| c = channel_new(ssh, ctype, SSH_CHANNEL_RDYNAMIC_OPEN, -1, -1, -1, |
| CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); |
| c->host_port = 0; |
| c->path = NULL; |
| |
| /* |
| * We need to open the channel before we have a FD, |
| * so that we can get SOCKS header from peer. |
| */ |
| if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->remote_id)) != 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("%s: channel %i: confirm: %s", __func__, |
| c->self, ssh_err(r)); |
| } |
| return c; |
| } |
| |
| /* Return CONNECTING socket to remote host:port or local socket path */ |
| static int |
| rdynamic_connect_finish(struct ssh *ssh, Channel *c) |
| { |
| struct channel_connect cctx; |
| int sock; |
| |
| memset(&cctx, 0, sizeof(cctx)); |
| sock = connect_to_helper(ssh, c->path, c->host_port, SOCK_STREAM, NULL, |
| NULL, &cctx, NULL, NULL); |
| if (sock == -1) |
| channel_connect_ctx_free(&cctx); |
| else { |
| /* similar to SSH_CHANNEL_CONNECTING but we've already sent the open */ |
| c->type = SSH_CHANNEL_RDYNAMIC_FINISH; |
| c->connect_ctx = cctx; |
| channel_register_fds(ssh, c, sock, sock, -1, 0, 1, 0); |
| } |
| return sock; |
| } |
| |
| /* -- 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(struct ssh *ssh, 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 = ssh->chanctxt->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) { |
| if ((errno != EINVAL) && (errno != EAFNOSUPPORT) |
| #ifdef EPFNOSUPPORT |
| && (errno != EPFNOSUPPORT) |
| #endif |
| ) { |
| error("socket: %.100s", strerror(errno)); |
| freeaddrinfo(aitop); |
| return -1; |
| } else { |
| debug("x11_create_display_inet: Socket family %d not supported", |
| ai->ai_family); |
| continue; |
| } |
| } |
| if (ai->ai_family == AF_INET6) |
| sock_set_v6only(sock); |
| if (x11_use_localhost) |
| set_reuseaddr(sock); |
| if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { |
| debug2("%s: bind port %d: %.100s", __func__, |
| 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(ssh, "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_path(const char *pathname) |
| { |
| 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; |
| strlcpy(addr.sun_path, pathname, sizeof addr.sun_path); |
| if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) |
| return sock; |
| close(sock); |
| error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); |
| return -1; |
| } |
| |
| static int |
| connect_local_xsocket(u_int dnr) |
| { |
| char buf[1024]; |
| snprintf(buf, sizeof buf, _PATH_UNIX_X, dnr); |
| return connect_local_xsocket_path(buf); |
| } |
| |
| #ifdef __APPLE__ |
| static int |
| is_path_to_xsocket(const char *display, char *path, size_t pathlen) |
| { |
| struct stat sbuf; |
| |
| if (strlcpy(path, display, pathlen) >= pathlen) { |
| error("%s: display path too long", __func__); |
| return 0; |
| } |
| if (display[0] != '/') |
| return 0; |
| if (stat(path, &sbuf) == 0) { |
| return 1; |
| } else { |
| char *dot = strrchr(path, '.'); |
| if (dot != NULL) { |
| *dot = '\0'; |
| if (stat(path, &sbuf) == 0) { |
| return 1; |
| } |
| } |
| } |
| return 0; |
| } |
| #endif |
| |
| int |
| x11_connect_display(struct ssh *ssh) |
| { |
| 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. |
| */ |
| |
| #ifdef __APPLE__ |
| /* Check if display is a path to a socket (as set by launchd). */ |
| { |
| char path[PATH_MAX]; |
| |
| if (is_path_to_xsocket(display, path, sizeof(path))) { |
| debug("x11_connect_display: $DISPLAY is launchd"); |
| |
| /* Create a socket. */ |
| sock = connect_local_xsocket_path(path); |
| if (sock < 0) |
| return -1; |
| |
| /* OK, we now have a connection to the display. */ |
| return sock; |
| } |
| } |
| #endif |
| /* |
| * 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 = ssh->chanctxt->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; |
| } |
| |
| /* |
| * 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(struct ssh *ssh, int client_session_id, |
| const char *disp, const char *proto, const char *data, int want_reply) |
| { |
| struct ssh_channels *sc = ssh->chanctxt; |
| u_int data_len = (u_int) strlen(data) / 2; |
| u_int i, value; |
| const char *cp; |
| char *new_data; |
| int r, screen_number; |
| |
| if (sc->x11_saved_display == NULL) |
| sc->x11_saved_display = xstrdup(disp); |
| else if (strcmp(disp, sc->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 (sc->x11_saved_proto == NULL) { |
| /* Save protocol name. */ |
| sc->x11_saved_proto = xstrdup(proto); |
| |
| /* Extract real authentication data. */ |
| sc->x11_saved_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); |
| sc->x11_saved_data[i] = value; |
| } |
| sc->x11_saved_data_len = data_len; |
| |
| /* Generate fake data of the same length. */ |
| sc->x11_fake_data = xmalloc(data_len); |
| arc4random_buf(sc->x11_fake_data, data_len); |
| sc->x11_fake_data_len = data_len; |
| } |
| |
| /* Convert the fake data into hex. */ |
| new_data = tohex(sc->x11_fake_data, data_len); |
| |
| /* Send the request packet. */ |
| channel_request_start(ssh, client_session_id, "x11-req", want_reply); |
| if ((r = sshpkt_put_u8(ssh, 0)) != 0 || /* bool: single connection */ |
| (r = sshpkt_put_cstring(ssh, proto)) != 0 || |
| (r = sshpkt_put_cstring(ssh, new_data)) != 0 || |
| (r = sshpkt_put_u32(ssh, screen_number)) != 0 || |
| (r = sshpkt_send(ssh)) != 0 || |
| (r = ssh_packet_write_wait(ssh)) != 0) |
| fatal("%s: send x11-req: %s", __func__, ssh_err(r)); |
| free(new_data); |
| } |