| /* $OpenBSD: channels.c,v 1.285 2008/07/13 22:13:07 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/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 <netdb.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <termios.h> |
| #include <unistd.h> |
| #include <stdarg.h> |
| |
| #include "openbsd-compat/sys-queue.h" |
| #include "xmalloc.h" |
| #include "ssh.h" |
| #include "ssh1.h" |
| #include "ssh2.h" |
| #include "packet.h" |
| #include "log.h" |
| #include "misc.h" |
| #include "buffer.h" |
| #include "channels.h" |
| #include "compat.h" |
| #include "canohost.h" |
| #include "key.h" |
| #include "authfd.h" |
| #include "pathnames.h" |
| |
| /* -- channel core */ |
| |
| /* |
| * Pointer to an array containing all allocated channels. The array is |
| * dynamically extended as needed. |
| */ |
| static Channel **channels = NULL; |
| |
| /* |
| * Size of the channel array. All slots of the array must always be |
| * initialized (at least the type field); unused slots set to NULL |
| */ |
| static u_int channels_alloc = 0; |
| |
| /* |
| * Maximum file descriptor value used in any of the channels. This is |
| * updated in channel_new. |
| */ |
| static int channel_max_fd = 0; |
| |
| |
| /* -- tcp forwarding */ |
| |
| /* |
| * Data structure for storing which hosts are permitted for forward requests. |
| * The local sides of any remote forwards are stored in this array to prevent |
| * a corrupt remote server from accessing arbitrary TCP/IP ports on our local |
| * network (which might be behind a firewall). |
| */ |
| typedef struct { |
| char *host_to_connect; /* Connect to 'host'. */ |
| u_short port_to_connect; /* Connect to 'port'. */ |
| u_short listen_port; /* Remote side should listen port number. */ |
| } ForwardPermission; |
| |
| /* List of all permitted host/port pairs to connect by the user. */ |
| static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION]; |
| |
| /* List of all permitted host/port pairs to connect by the admin. */ |
| static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION]; |
| |
| /* Number of permitted host/port pairs in the array permitted by the user. */ |
| static int num_permitted_opens = 0; |
| |
| /* Number of permitted host/port pair in the array permitted by the admin. */ |
| static int num_adm_permitted_opens = 0; |
| |
| /* |
| * If this is true, all opens are permitted. This is the case on the server |
| * on which we have to trust the client anyway, and the user could do |
| * anything after logging in anyway. |
| */ |
| static int all_opens_permitted = 0; |
| |
| |
| /* -- X11 forwarding */ |
| |
| /* Maximum number of fake X11 displays to try. */ |
| #define MAX_DISPLAYS 1000 |
| |
| /* Saved X11 local (client) display. */ |
| static char *x11_saved_display = NULL; |
| |
| /* Saved X11 authentication protocol name. */ |
| static char *x11_saved_proto = NULL; |
| |
| /* Saved X11 authentication data. This is the real data. */ |
| static char *x11_saved_data = NULL; |
| static u_int x11_saved_data_len = 0; |
| |
| /* |
| * Fake X11 authentication data. This is what the server will be sending us; |
| * we should replace any occurrences of this by the real data. |
| */ |
| static u_char *x11_fake_data = NULL; |
| static u_int x11_fake_data_len; |
| |
| |
| /* -- agent forwarding */ |
| |
| #define NUM_SOCKS 10 |
| |
| /* AF_UNSPEC or AF_INET or AF_INET6 */ |
| static int IPv4or6 = AF_UNSPEC; |
| |
| /* helper */ |
| static void port_open_helper(Channel *c, char *rtype); |
| |
| /* non-blocking connect helpers */ |
| static int connect_next(struct channel_connect *); |
| static void channel_connect_ctx_free(struct channel_connect *); |
| |
| /* -- channel core */ |
| |
| Channel * |
| channel_by_id(int id) |
| { |
| Channel *c; |
| |
| if (id < 0 || (u_int)id >= channels_alloc) { |
| logit("channel_by_id: %d: bad id", id); |
| return NULL; |
| } |
| c = channels[id]; |
| if (c == NULL) { |
| logit("channel_by_id: %d: bad id: channel free", id); |
| return NULL; |
| } |
| return c; |
| } |
| |
| /* |
| * Returns the channel if it is allowed to receive protocol messages. |
| * Private channels, like listening sockets, may not receive messages. |
| */ |
| Channel * |
| channel_lookup(int id) |
| { |
| Channel *c; |
| |
| if ((c = channel_by_id(id)) == NULL) |
| return (NULL); |
| |
| switch (c->type) { |
| case SSH_CHANNEL_X11_OPEN: |
| case SSH_CHANNEL_LARVAL: |
| case SSH_CHANNEL_CONNECTING: |
| case SSH_CHANNEL_DYNAMIC: |
| case SSH_CHANNEL_OPENING: |
| case SSH_CHANNEL_OPEN: |
| case SSH_CHANNEL_INPUT_DRAINING: |
| case SSH_CHANNEL_OUTPUT_DRAINING: |
| return (c); |
| } |
| logit("Non-public channel %d, type %d.", id, c->type); |
| return (NULL); |
| } |
| |
| /* |
| * Register filedescriptors for a channel, used when allocating a channel or |
| * when the channel consumer/producer is ready, e.g. shell exec'd |
| */ |
| static void |
| channel_register_fds(Channel *c, int rfd, int wfd, int efd, |
| int extusage, int nonblock, int is_tty) |
| { |
| /* Update the maximum file descriptor value. */ |
| channel_max_fd = MAX(channel_max_fd, rfd); |
| channel_max_fd = MAX(channel_max_fd, wfd); |
| channel_max_fd = MAX(channel_max_fd, efd); |
| |
| /* XXX set close-on-exec -markus */ |
| |
| c->rfd = rfd; |
| c->wfd = wfd; |
| c->sock = (rfd == wfd) ? rfd : -1; |
| c->ctl_fd = -1; /* XXX: set elsewhere */ |
| c->efd = efd; |
| c->extended_usage = extusage; |
| |
| if ((c->isatty = is_tty) != 0) |
| debug2("channel %d: rfd %d isatty", c->self, c->rfd); |
| c->wfd_isatty = is_tty || isatty(c->wfd); |
| |
| /* enable nonblocking mode */ |
| if (nonblock) { |
| if (rfd != -1) |
| set_nonblock(rfd); |
| if (wfd != -1) |
| set_nonblock(wfd); |
| if (efd != -1) |
| set_nonblock(efd); |
| } |
| } |
| |
| /* |
| * Allocate a new channel object and set its type and socket. This will cause |
| * remote_name to be freed. |
| */ |
| Channel * |
| channel_new(char *ctype, int type, int rfd, int wfd, int efd, |
| u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock) |
| { |
| int found; |
| u_int i; |
| Channel *c; |
| |
| /* Do initial allocation if this is the first call. */ |
| if (channels_alloc == 0) { |
| channels_alloc = 10; |
| channels = xcalloc(channels_alloc, sizeof(Channel *)); |
| for (i = 0; i < channels_alloc; i++) |
| channels[i] = NULL; |
| } |
| /* Try to find a free slot where to put the new channel. */ |
| for (found = -1, i = 0; i < channels_alloc; i++) |
| if (channels[i] == NULL) { |
| /* Found a free slot. */ |
| found = (int)i; |
| break; |
| } |
| if (found < 0) { |
| /* There are no free slots. Take last+1 slot and expand the array. */ |
| found = channels_alloc; |
| if (channels_alloc > 10000) |
| fatal("channel_new: internal error: channels_alloc %d " |
| "too big.", channels_alloc); |
| channels = xrealloc(channels, channels_alloc + 10, |
| sizeof(Channel *)); |
| channels_alloc += 10; |
| debug2("channel: expanding %d", channels_alloc); |
| for (i = found; i < channels_alloc; i++) |
| channels[i] = NULL; |
| } |
| /* Initialize and return new channel. */ |
| c = channels[found] = xcalloc(1, sizeof(Channel)); |
| buffer_init(&c->input); |
| buffer_init(&c->output); |
| buffer_init(&c->extended); |
| c->ostate = CHAN_OUTPUT_OPEN; |
| c->istate = CHAN_INPUT_OPEN; |
| c->flags = 0; |
| channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, 0); |
| c->self = found; |
| c->type = type; |
| c->ctype = ctype; |
| c->local_window = window; |
| c->local_window_max = window; |
| c->local_consumed = 0; |
| c->local_maxpacket = maxpack; |
| c->remote_id = -1; |
| c->remote_name = xstrdup(remote_name); |
| c->remote_window = 0; |
| c->remote_maxpacket = 0; |
| c->force_drain = 0; |
| c->single_connection = 0; |
| c->detach_user = NULL; |
| c->detach_close = 0; |
| c->open_confirm = NULL; |
| c->open_confirm_ctx = NULL; |
| c->input_filter = NULL; |
| c->output_filter = NULL; |
| c->filter_ctx = NULL; |
| c->filter_cleanup = NULL; |
| TAILQ_INIT(&c->status_confirms); |
| debug("channel %d: new [%s]", found, remote_name); |
| return c; |
| } |
| |
| static int |
| channel_find_maxfd(void) |
| { |
| u_int i; |
| int max = 0; |
| Channel *c; |
| |
| for (i = 0; i < channels_alloc; i++) { |
| c = channels[i]; |
| if (c != NULL) { |
| max = MAX(max, c->rfd); |
| max = MAX(max, c->wfd); |
| max = MAX(max, c->efd); |
| } |
| } |
| return max; |
| } |
| |
| int |
| channel_close_fd(int *fdp) |
| { |
| int ret = 0, fd = *fdp; |
| |
| if (fd != -1) { |
| ret = close(fd); |
| *fdp = -1; |
| if (fd == channel_max_fd) |
| channel_max_fd = channel_find_maxfd(); |
| } |
| return ret; |
| } |
| |
| /* Close all channel fd/socket. */ |
| static void |
| channel_close_fds(Channel *c) |
| { |
| debug3("channel %d: close_fds r %d w %d e %d c %d", |
| c->self, c->rfd, c->wfd, c->efd, c->ctl_fd); |
| |
| channel_close_fd(&c->sock); |
| channel_close_fd(&c->ctl_fd); |
| channel_close_fd(&c->rfd); |
| channel_close_fd(&c->wfd); |
| channel_close_fd(&c->efd); |
| } |
| |
| /* Free the channel and close its fd/socket. */ |
| void |
| channel_free(Channel *c) |
| { |
| char *s; |
| u_int i, n; |
| struct channel_confirm *cc; |
| |
| for (n = 0, i = 0; i < channels_alloc; i++) |
| if (channels[i]) |
| n++; |
| debug("channel %d: free: %s, nchannels %u", c->self, |
| c->remote_name ? c->remote_name : "???", n); |
| |
| s = channel_open_message(); |
| debug3("channel %d: status: %s", c->self, s); |
| xfree(s); |
| |
| if (c->sock != -1) |
| shutdown(c->sock, SHUT_RDWR); |
| if (c->ctl_fd != -1) |
| shutdown(c->ctl_fd, SHUT_RDWR); |
| channel_close_fds(c); |
| buffer_free(&c->input); |
| buffer_free(&c->output); |
| buffer_free(&c->extended); |
| if (c->remote_name) { |
| xfree(c->remote_name); |
| c->remote_name = NULL; |
| } |
| while ((cc = TAILQ_FIRST(&c->status_confirms)) != NULL) { |
| if (cc->abandon_cb != NULL) |
| cc->abandon_cb(c, cc->ctx); |
| TAILQ_REMOVE(&c->status_confirms, cc, entry); |
| bzero(cc, sizeof(*cc)); |
| xfree(cc); |
| } |
| if (c->filter_cleanup != NULL && c->filter_ctx != NULL) |
| c->filter_cleanup(c->self, c->filter_ctx); |
| channels[c->self] = NULL; |
| xfree(c); |
| } |
| |
| void |
| channel_free_all(void) |
| { |
| u_int i; |
| |
| for (i = 0; i < channels_alloc; i++) |
| if (channels[i] != NULL) |
| channel_free(channels[i]); |
| } |
| |
| /* |
| * Closes the sockets/fds of all channels. This is used to close extra file |
| * descriptors after a fork. |
| */ |
| void |
| channel_close_all(void) |
| { |
| u_int i; |
| |
| for (i = 0; i < channels_alloc; i++) |
| if (channels[i] != NULL) |
| channel_close_fds(channels[i]); |
| } |
| |
| /* |
| * Stop listening to channels. |
| */ |
| void |
| channel_stop_listening(void) |
| { |
| u_int i; |
| Channel *c; |
| |
| for (i = 0; i < channels_alloc; i++) { |
| c = channels[i]; |
| if (c != NULL) { |
| switch (c->type) { |
| case SSH_CHANNEL_AUTH_SOCKET: |
| case SSH_CHANNEL_PORT_LISTENER: |
| case SSH_CHANNEL_RPORT_LISTENER: |
| case SSH_CHANNEL_X11_LISTENER: |
| channel_close_fd(&c->sock); |
| channel_free(c); |
| break; |
| } |
| } |
| } |
| } |
| |
| /* |
| * Returns true if no channel has too much buffered data, and false if one or |
| * more channel is overfull. |
| */ |
| int |
| channel_not_very_much_buffered_data(void) |
| { |
| u_int i; |
| Channel *c; |
| |
| for (i = 0; i < channels_alloc; i++) { |
| c = channels[i]; |
| if (c != NULL && c->type == SSH_CHANNEL_OPEN) { |
| #if 0 |
| if (!compat20 && |
| buffer_len(&c->input) > packet_get_maxsize()) { |
| debug2("channel %d: big input buffer %d", |
| c->self, buffer_len(&c->input)); |
| return 0; |
| } |
| #endif |
| if (buffer_len(&c->output) > packet_get_maxsize()) { |
| debug2("channel %d: big output buffer %u > %u", |
| c->self, buffer_len(&c->output), |
| packet_get_maxsize()); |
| return 0; |
| } |
| } |
| } |
| return 1; |
| } |
| |
| /* Returns true if any channel is still open. */ |
| int |
| channel_still_open(void) |
| { |
| u_int i; |
| Channel *c; |
| |
| for (i = 0; i < channels_alloc; i++) { |
| c = channels[i]; |
| if (c == NULL) |
| continue; |
| switch (c->type) { |
| case SSH_CHANNEL_X11_LISTENER: |
| case SSH_CHANNEL_PORT_LISTENER: |
| case SSH_CHANNEL_RPORT_LISTENER: |
| case SSH_CHANNEL_CLOSED: |
| case SSH_CHANNEL_AUTH_SOCKET: |
| case SSH_CHANNEL_DYNAMIC: |
| case SSH_CHANNEL_CONNECTING: |
| case SSH_CHANNEL_ZOMBIE: |
| continue; |
| case SSH_CHANNEL_LARVAL: |
| if (!compat20) |
| fatal("cannot happen: SSH_CHANNEL_LARVAL"); |
| continue; |
| case SSH_CHANNEL_OPENING: |
| case SSH_CHANNEL_OPEN: |
| case SSH_CHANNEL_X11_OPEN: |
| return 1; |
| case SSH_CHANNEL_INPUT_DRAINING: |
| case SSH_CHANNEL_OUTPUT_DRAINING: |
| if (!compat13) |
| fatal("cannot happen: OUT_DRAIN"); |
| return 1; |
| default: |
| fatal("channel_still_open: bad channel type %d", c->type); |
| /* NOTREACHED */ |
| } |
| } |
| return 0; |
| } |
| |
| /* Returns the id of an open channel suitable for keepaliving */ |
| int |
| channel_find_open(void) |
| { |
| u_int i; |
| Channel *c; |
| |
| for (i = 0; i < channels_alloc; i++) { |
| c = channels[i]; |
| if (c == NULL || c->remote_id < 0) |
| continue; |
| switch (c->type) { |
| case SSH_CHANNEL_CLOSED: |
| case SSH_CHANNEL_DYNAMIC: |
| case SSH_CHANNEL_X11_LISTENER: |
| case SSH_CHANNEL_PORT_LISTENER: |
| case SSH_CHANNEL_RPORT_LISTENER: |
| case SSH_CHANNEL_OPENING: |
| case SSH_CHANNEL_CONNECTING: |
| case SSH_CHANNEL_ZOMBIE: |
| continue; |
| case SSH_CHANNEL_LARVAL: |
| case SSH_CHANNEL_AUTH_SOCKET: |
| case SSH_CHANNEL_OPEN: |
| case SSH_CHANNEL_X11_OPEN: |
| return i; |
| case SSH_CHANNEL_INPUT_DRAINING: |
| case SSH_CHANNEL_OUTPUT_DRAINING: |
| if (!compat13) |
| fatal("cannot happen: OUT_DRAIN"); |
| return i; |
| default: |
| fatal("channel_find_open: bad channel type %d", c->type); |
| /* NOTREACHED */ |
| } |
| } |
| return -1; |
| } |
| |
| |
| /* |
| * Returns a message describing the currently open forwarded connections, |
| * suitable for sending to the client. The message contains crlf pairs for |
| * newlines. |
| */ |
| char * |
| channel_open_message(void) |
| { |
| Buffer buffer; |
| Channel *c; |
| char buf[1024], *cp; |
| u_int i; |
| |
| buffer_init(&buffer); |
| snprintf(buf, sizeof buf, "The following connections are open:\r\n"); |
| buffer_append(&buffer, buf, strlen(buf)); |
| for (i = 0; i < channels_alloc; i++) { |
| c = channels[i]; |
| if (c == NULL) |
| continue; |
| switch (c->type) { |
| case SSH_CHANNEL_X11_LISTENER: |
| case SSH_CHANNEL_PORT_LISTENER: |
| case SSH_CHANNEL_RPORT_LISTENER: |
| case SSH_CHANNEL_CLOSED: |
| case SSH_CHANNEL_AUTH_SOCKET: |
| case SSH_CHANNEL_ZOMBIE: |
| continue; |
| case SSH_CHANNEL_LARVAL: |
| case SSH_CHANNEL_OPENING: |
| case SSH_CHANNEL_CONNECTING: |
| case SSH_CHANNEL_DYNAMIC: |
| case SSH_CHANNEL_OPEN: |
| case SSH_CHANNEL_X11_OPEN: |
| case SSH_CHANNEL_INPUT_DRAINING: |
| case SSH_CHANNEL_OUTPUT_DRAINING: |
| snprintf(buf, sizeof buf, |
| " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n", |
| c->self, c->remote_name, |
| c->type, c->remote_id, |
| c->istate, buffer_len(&c->input), |
| c->ostate, buffer_len(&c->output), |
| c->rfd, c->wfd, c->ctl_fd); |
| buffer_append(&buffer, buf, strlen(buf)); |
| continue; |
| default: |
| fatal("channel_open_message: bad channel type %d", c->type); |
| /* NOTREACHED */ |
| } |
| } |
| buffer_append(&buffer, "\0", 1); |
| cp = xstrdup(buffer_ptr(&buffer)); |
| buffer_free(&buffer); |
| return cp; |
| } |
| |
| void |
| channel_send_open(int id) |
| { |
| Channel *c = channel_lookup(id); |
| |
| if (c == NULL) { |
| logit("channel_send_open: %d: bad id", id); |
| return; |
| } |
| debug2("channel %d: send open", id); |
| packet_start(SSH2_MSG_CHANNEL_OPEN); |
| packet_put_cstring(c->ctype); |
| packet_put_int(c->self); |
| packet_put_int(c->local_window); |
| packet_put_int(c->local_maxpacket); |
| packet_send(); |
| } |
| |
| void |
| channel_request_start(int id, char *service, int wantconfirm) |
| { |
| Channel *c = channel_lookup(id); |
| |
| if (c == NULL) { |
| logit("channel_request_start: %d: unknown channel id", id); |
| return; |
| } |
| debug2("channel %d: request %s confirm %d", id, service, wantconfirm); |
| packet_start(SSH2_MSG_CHANNEL_REQUEST); |
| packet_put_int(c->remote_id); |
| packet_put_cstring(service); |
| packet_put_char(wantconfirm); |
| } |
| |
| void |
| channel_register_status_confirm(int id, channel_confirm_cb *cb, |
| channel_confirm_abandon_cb *abandon_cb, void *ctx) |
| { |
| struct channel_confirm *cc; |
| Channel *c; |
| |
| if ((c = channel_lookup(id)) == NULL) |
| fatal("channel_register_expect: %d: bad id", id); |
| |
| cc = xmalloc(sizeof(*cc)); |
| cc->cb = cb; |
| cc->abandon_cb = abandon_cb; |
| cc->ctx = ctx; |
| TAILQ_INSERT_TAIL(&c->status_confirms, cc, entry); |
| } |
| |
| void |
| channel_register_open_confirm(int id, channel_callback_fn *fn, void *ctx) |
| { |
| Channel *c = channel_lookup(id); |
| |
| if (c == NULL) { |
| logit("channel_register_open_comfirm: %d: bad id", id); |
| return; |
| } |
| c->open_confirm = fn; |
| c->open_confirm_ctx = ctx; |
| } |
| |
| void |
| channel_register_cleanup(int id, channel_callback_fn *fn, int do_close) |
| { |
| Channel *c = channel_by_id(id); |
| |
| if (c == NULL) { |
| logit("channel_register_cleanup: %d: bad id", id); |
| return; |
| } |
| c->detach_user = fn; |
| c->detach_close = do_close; |
| } |
| |
| void |
| channel_cancel_cleanup(int id) |
| { |
| Channel *c = channel_by_id(id); |
| |
| if (c == NULL) { |
| logit("channel_cancel_cleanup: %d: bad id", id); |
| return; |
| } |
| c->detach_user = NULL; |
| c->detach_close = 0; |
| } |
| |
| void |
| channel_register_filter(int id, channel_infilter_fn *ifn, |
| channel_outfilter_fn *ofn, channel_filter_cleanup_fn *cfn, void *ctx) |
| { |
| Channel *c = channel_lookup(id); |
| |
| if (c == NULL) { |
| logit("channel_register_filter: %d: bad id", id); |
| return; |
| } |
| c->input_filter = ifn; |
| c->output_filter = ofn; |
| c->filter_ctx = ctx; |
| c->filter_cleanup = cfn; |
| } |
| |
| void |
| channel_set_fds(int id, int rfd, int wfd, int efd, |
| int extusage, int nonblock, int is_tty, u_int window_max) |
| { |
| Channel *c = channel_lookup(id); |
| |
| if (c == NULL || c->type != SSH_CHANNEL_LARVAL) |
| fatal("channel_activate for non-larval channel %d.", id); |
| channel_register_fds(c, rfd, wfd, efd, extusage, nonblock, is_tty); |
| c->type = SSH_CHANNEL_OPEN; |
| c->local_window = c->local_window_max = window_max; |
| packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); |
| packet_put_int(c->remote_id); |
| packet_put_int(c->local_window); |
| packet_send(); |
| } |
| |
| /* |
| * 'channel_pre*' are called just before select() to add any bits relevant to |
| * channels in the select bitmasks. |
| */ |
| /* |
| * 'channel_post*': perform any appropriate operations for channels which |
| * have events pending. |
| */ |
| typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset); |
| chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE]; |
| chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE]; |
| |
| /* ARGSUSED */ |
| static void |
| channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| FD_SET(c->sock, readset); |
| } |
| |
| /* ARGSUSED */ |
| static void |
| channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| debug3("channel %d: waiting for connection", c->self); |
| FD_SET(c->sock, writeset); |
| } |
| |
| static void |
| channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| if (buffer_len(&c->input) < packet_get_maxsize()) |
| FD_SET(c->sock, readset); |
| if (buffer_len(&c->output) > 0) |
| FD_SET(c->sock, writeset); |
| } |
| |
| static void |
| channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| u_int limit = compat20 ? c->remote_window : packet_get_maxsize(); |
| |
| if (c->istate == CHAN_INPUT_OPEN && |
| limit > 0 && |
| buffer_len(&c->input) < limit && |
| buffer_check_alloc(&c->input, CHAN_RBUF)) |
| FD_SET(c->rfd, readset); |
| if (c->ostate == CHAN_OUTPUT_OPEN || |
| c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { |
| if (buffer_len(&c->output) > 0) { |
| FD_SET(c->wfd, writeset); |
| } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { |
| if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) |
| debug2("channel %d: obuf_empty delayed efd %d/(%d)", |
| c->self, c->efd, buffer_len(&c->extended)); |
| else |
| chan_obuf_empty(c); |
| } |
| } |
| /** XXX check close conditions, too */ |
| if (compat20 && c->efd != -1 && |
| !(c->istate == CHAN_INPUT_CLOSED && c->ostate == CHAN_OUTPUT_CLOSED)) { |
| if (c->extended_usage == CHAN_EXTENDED_WRITE && |
| buffer_len(&c->extended) > 0) |
| FD_SET(c->efd, writeset); |
| else if (!(c->flags & CHAN_EOF_SENT) && |
| c->extended_usage == CHAN_EXTENDED_READ && |
| buffer_len(&c->extended) < c->remote_window) |
| FD_SET(c->efd, readset); |
| } |
| /* XXX: What about efd? races? */ |
| if (compat20 && c->ctl_fd != -1 && |
| c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN) |
| FD_SET(c->ctl_fd, readset); |
| } |
| |
| /* ARGSUSED */ |
| static void |
| channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| if (buffer_len(&c->input) == 0) { |
| packet_start(SSH_MSG_CHANNEL_CLOSE); |
| packet_put_int(c->remote_id); |
| packet_send(); |
| c->type = SSH_CHANNEL_CLOSED; |
| debug2("channel %d: closing after input drain.", c->self); |
| } |
| } |
| |
| /* ARGSUSED */ |
| static void |
| channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| if (buffer_len(&c->output) == 0) |
| chan_mark_dead(c); |
| else |
| FD_SET(c->sock, writeset); |
| } |
| |
| /* |
| * This is a special state for X11 authentication spoofing. An opened X11 |
| * connection (when authentication spoofing is being done) remains in this |
| * state until the first packet has been completely read. The authentication |
| * data in that packet is then substituted by the real data if it matches the |
| * fake data, and the channel is put into normal mode. |
| * XXX All this happens at the client side. |
| * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok |
| */ |
| static int |
| x11_open_helper(Buffer *b) |
| { |
| u_char *ucp; |
| u_int proto_len, data_len; |
| |
| /* Check if the fixed size part of the packet is in buffer. */ |
| if (buffer_len(b) < 12) |
| return 0; |
| |
| /* Parse the lengths of variable-length fields. */ |
| ucp = buffer_ptr(b); |
| if (ucp[0] == 0x42) { /* Byte order MSB first. */ |
| proto_len = 256 * ucp[6] + ucp[7]; |
| data_len = 256 * ucp[8] + ucp[9]; |
| } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ |
| proto_len = ucp[6] + 256 * ucp[7]; |
| data_len = ucp[8] + 256 * ucp[9]; |
| } else { |
| debug2("Initial X11 packet contains bad byte order byte: 0x%x", |
| ucp[0]); |
| return -1; |
| } |
| |
| /* Check if the whole packet is in buffer. */ |
| if (buffer_len(b) < |
| 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) |
| return 0; |
| |
| /* Check if authentication protocol matches. */ |
| if (proto_len != strlen(x11_saved_proto) || |
| memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) { |
| debug2("X11 connection uses different authentication protocol."); |
| return -1; |
| } |
| /* Check if authentication data matches our fake data. */ |
| if (data_len != x11_fake_data_len || |
| memcmp(ucp + 12 + ((proto_len + 3) & ~3), |
| x11_fake_data, x11_fake_data_len) != 0) { |
| debug2("X11 auth data does not match fake data."); |
| return -1; |
| } |
| /* Check fake data length */ |
| if (x11_fake_data_len != x11_saved_data_len) { |
| error("X11 fake_data_len %d != saved_data_len %d", |
| x11_fake_data_len, x11_saved_data_len); |
| return -1; |
| } |
| /* |
| * Received authentication protocol and data match |
| * our fake data. Substitute the fake data with real |
| * data. |
| */ |
| memcpy(ucp + 12 + ((proto_len + 3) & ~3), |
| x11_saved_data, x11_saved_data_len); |
| return 1; |
| } |
| |
| static void |
| channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| int ret = x11_open_helper(&c->output); |
| |
| if (ret == 1) { |
| /* Start normal processing for the channel. */ |
| c->type = SSH_CHANNEL_OPEN; |
| channel_pre_open_13(c, readset, writeset); |
| } else if (ret == -1) { |
| /* |
| * We have received an X11 connection that has bad |
| * authentication information. |
| */ |
| logit("X11 connection rejected because of wrong authentication."); |
| buffer_clear(&c->input); |
| buffer_clear(&c->output); |
| channel_close_fd(&c->sock); |
| c->sock = -1; |
| c->type = SSH_CHANNEL_CLOSED; |
| packet_start(SSH_MSG_CHANNEL_CLOSE); |
| packet_put_int(c->remote_id); |
| packet_send(); |
| } |
| } |
| |
| static void |
| channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| int ret = x11_open_helper(&c->output); |
| |
| /* c->force_drain = 1; */ |
| |
| if (ret == 1) { |
| c->type = SSH_CHANNEL_OPEN; |
| channel_pre_open(c, readset, writeset); |
| } else if (ret == -1) { |
| logit("X11 connection rejected because of wrong authentication."); |
| debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate); |
| chan_read_failed(c); |
| buffer_clear(&c->input); |
| chan_ibuf_empty(c); |
| buffer_clear(&c->output); |
| /* for proto v1, the peer will send an IEOF */ |
| if (compat20) |
| chan_write_failed(c); |
| else |
| c->type = SSH_CHANNEL_OPEN; |
| debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); |
| } |
| } |
| |
| /* try to decode a socks4 header */ |
| /* ARGSUSED */ |
| static int |
| channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| char *p, *host; |
| u_int len, have, i, found; |
| char username[256]; |
| struct { |
| u_int8_t version; |
| u_int8_t command; |
| u_int16_t dest_port; |
| struct in_addr dest_addr; |
| } s4_req, s4_rsp; |
| |
| debug2("channel %d: decode socks4", c->self); |
| |
| have = buffer_len(&c->input); |
| len = sizeof(s4_req); |
| if (have < len) |
| return 0; |
| p = buffer_ptr(&c->input); |
| for (found = 0, i = len; i < have; i++) { |
| if (p[i] == '\0') { |
| found = 1; |
| break; |
| } |
| if (i > 1024) { |
| /* the peer is probably sending garbage */ |
| debug("channel %d: decode socks4: too long", |
| c->self); |
| return -1; |
| } |
| } |
| if (!found) |
| return 0; |
| buffer_get(&c->input, (char *)&s4_req.version, 1); |
| buffer_get(&c->input, (char *)&s4_req.command, 1); |
| buffer_get(&c->input, (char *)&s4_req.dest_port, 2); |
| buffer_get(&c->input, (char *)&s4_req.dest_addr, 4); |
| have = buffer_len(&c->input); |
| p = buffer_ptr(&c->input); |
| len = strlen(p); |
| debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); |
| if (len > have) |
| fatal("channel %d: decode socks4: len %d > have %d", |
| c->self, len, have); |
| strlcpy(username, p, sizeof(username)); |
| buffer_consume(&c->input, len); |
| buffer_consume(&c->input, 1); /* trailing '\0' */ |
| |
| host = inet_ntoa(s4_req.dest_addr); |
| strlcpy(c->path, host, sizeof(c->path)); |
| c->host_port = ntohs(s4_req.dest_port); |
| |
| debug2("channel %d: dynamic request: socks4 host %s port %u command %u", |
| c->self, host, c->host_port, s4_req.command); |
| |
| if (s4_req.command != 1) { |
| debug("channel %d: cannot handle: socks4 cn %d", |
| c->self, s4_req.command); |
| return -1; |
| } |
| s4_rsp.version = 0; /* vn: 0 for reply */ |
| s4_rsp.command = 90; /* cd: req granted */ |
| s4_rsp.dest_port = 0; /* ignored */ |
| s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ |
| buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp)); |
| return 1; |
| } |
| |
| /* try to decode a socks5 header */ |
| #define SSH_SOCKS5_AUTHDONE 0x1000 |
| #define SSH_SOCKS5_NOAUTH 0x00 |
| #define SSH_SOCKS5_IPV4 0x01 |
| #define SSH_SOCKS5_DOMAIN 0x03 |
| #define SSH_SOCKS5_IPV6 0x04 |
| #define SSH_SOCKS5_CONNECT 0x01 |
| #define SSH_SOCKS5_SUCCESS 0x00 |
| |
| /* ARGSUSED */ |
| static int |
| channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| struct { |
| u_int8_t version; |
| u_int8_t command; |
| u_int8_t reserved; |
| u_int8_t atyp; |
| } s5_req, s5_rsp; |
| u_int16_t dest_port; |
| u_char *p, dest_addr[255+1]; |
| u_int have, need, i, found, nmethods, addrlen, af; |
| |
| debug2("channel %d: decode socks5", c->self); |
| p = buffer_ptr(&c->input); |
| if (p[0] != 0x05) |
| return -1; |
| have = buffer_len(&c->input); |
| if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { |
| /* format: ver | nmethods | methods */ |
| if (have < 2) |
| return 0; |
| nmethods = p[1]; |
| if (have < nmethods + 2) |
| return 0; |
| /* look for method: "NO AUTHENTICATION REQUIRED" */ |
| for (found = 0, i = 2; i < nmethods + 2; i++) { |
| if (p[i] == SSH_SOCKS5_NOAUTH) { |
| found = 1; |
| break; |
| } |
| } |
| if (!found) { |
| debug("channel %d: method SSH_SOCKS5_NOAUTH not found", |
| c->self); |
| return -1; |
| } |
| buffer_consume(&c->input, nmethods + 2); |
| buffer_put_char(&c->output, 0x05); /* version */ |
| buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */ |
| FD_SET(c->sock, writeset); |
| c->flags |= SSH_SOCKS5_AUTHDONE; |
| debug2("channel %d: socks5 auth done", c->self); |
| return 0; /* need more */ |
| } |
| debug2("channel %d: socks5 post auth", c->self); |
| if (have < sizeof(s5_req)+1) |
| return 0; /* need more */ |
| memcpy(&s5_req, p, sizeof(s5_req)); |
| if (s5_req.version != 0x05 || |
| s5_req.command != SSH_SOCKS5_CONNECT || |
| s5_req.reserved != 0x00) { |
| debug2("channel %d: only socks5 connect supported", c->self); |
| return -1; |
| } |
| switch (s5_req.atyp){ |
| case SSH_SOCKS5_IPV4: |
| addrlen = 4; |
| af = AF_INET; |
| break; |
| case SSH_SOCKS5_DOMAIN: |
| addrlen = p[sizeof(s5_req)]; |
| af = -1; |
| break; |
| case SSH_SOCKS5_IPV6: |
| addrlen = 16; |
| af = AF_INET6; |
| break; |
| default: |
| debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); |
| return -1; |
| } |
| need = sizeof(s5_req) + addrlen + 2; |
| if (s5_req.atyp == SSH_SOCKS5_DOMAIN) |
| need++; |
| if (have < need) |
| return 0; |
| buffer_consume(&c->input, sizeof(s5_req)); |
| if (s5_req.atyp == SSH_SOCKS5_DOMAIN) |
| buffer_consume(&c->input, 1); /* host string length */ |
| buffer_get(&c->input, (char *)&dest_addr, addrlen); |
| buffer_get(&c->input, (char *)&dest_port, 2); |
| dest_addr[addrlen] = '\0'; |
| if (s5_req.atyp == SSH_SOCKS5_DOMAIN) |
| strlcpy(c->path, (char *)dest_addr, sizeof(c->path)); |
| else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL) |
| return -1; |
| c->host_port = ntohs(dest_port); |
| |
| debug2("channel %d: dynamic request: socks5 host %s port %u command %u", |
| c->self, c->path, c->host_port, s5_req.command); |
| |
| s5_rsp.version = 0x05; |
| s5_rsp.command = SSH_SOCKS5_SUCCESS; |
| s5_rsp.reserved = 0; /* ignored */ |
| s5_rsp.atyp = SSH_SOCKS5_IPV4; |
| ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY; |
| dest_port = 0; /* ignored */ |
| |
| buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp)); |
| buffer_append(&c->output, &dest_addr, sizeof(struct in_addr)); |
| buffer_append(&c->output, &dest_port, sizeof(dest_port)); |
| return 1; |
| } |
| |
| /* dynamic port forwarding */ |
| static void |
| channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| u_char *p; |
| u_int have; |
| int ret; |
| |
| have = buffer_len(&c->input); |
| c->delayed = 0; |
| debug2("channel %d: pre_dynamic: have %d", c->self, have); |
| /* buffer_dump(&c->input); */ |
| /* check if the fixed size part of the packet is in buffer. */ |
| if (have < 3) { |
| /* need more */ |
| FD_SET(c->sock, readset); |
| return; |
| } |
| /* try to guess the protocol */ |
| p = buffer_ptr(&c->input); |
| switch (p[0]) { |
| case 0x04: |
| ret = channel_decode_socks4(c, readset, writeset); |
| break; |
| case 0x05: |
| ret = channel_decode_socks5(c, readset, writeset); |
| break; |
| default: |
| ret = -1; |
| break; |
| } |
| if (ret < 0) { |
| chan_mark_dead(c); |
| } else if (ret == 0) { |
| debug2("channel %d: pre_dynamic: need more", c->self); |
| /* need more */ |
| FD_SET(c->sock, readset); |
| } else { |
| /* switch to the next state */ |
| c->type = SSH_CHANNEL_OPENING; |
| port_open_helper(c, "direct-tcpip"); |
| } |
| } |
| |
| /* This is our fake X11 server socket. */ |
| /* ARGSUSED */ |
| static void |
| channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| Channel *nc; |
| struct sockaddr_storage addr; |
| int newsock; |
| socklen_t addrlen; |
| char buf[16384], *remote_ipaddr; |
| int remote_port; |
| |
| if (FD_ISSET(c->sock, readset)) { |
| debug("X11 connection requested."); |
| addrlen = sizeof(addr); |
| newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); |
| if (c->single_connection) { |
| debug2("single_connection: closing X11 listener."); |
| channel_close_fd(&c->sock); |
| chan_mark_dead(c); |
| } |
| if (newsock < 0) { |
| error("accept: %.100s", strerror(errno)); |
| return; |
| } |
| set_nodelay(newsock); |
| remote_ipaddr = get_peer_ipaddr(newsock); |
| remote_port = get_peer_port(newsock); |
| snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", |
| remote_ipaddr, remote_port); |
| |
| nc = channel_new("accepted x11 socket", |
| SSH_CHANNEL_OPENING, newsock, newsock, -1, |
| c->local_window_max, c->local_maxpacket, 0, buf, 1); |
| if (compat20) { |
| packet_start(SSH2_MSG_CHANNEL_OPEN); |
| packet_put_cstring("x11"); |
| packet_put_int(nc->self); |
| packet_put_int(nc->local_window_max); |
| packet_put_int(nc->local_maxpacket); |
| /* originator ipaddr and port */ |
| packet_put_cstring(remote_ipaddr); |
| if (datafellows & SSH_BUG_X11FWD) { |
| debug2("ssh2 x11 bug compat mode"); |
| } else { |
| packet_put_int(remote_port); |
| } |
| packet_send(); |
| } else { |
| packet_start(SSH_SMSG_X11_OPEN); |
| packet_put_int(nc->self); |
| if (packet_get_protocol_flags() & |
| SSH_PROTOFLAG_HOST_IN_FWD_OPEN) |
| packet_put_cstring(buf); |
| packet_send(); |
| } |
| xfree(remote_ipaddr); |
| } |
| } |
| |
| static void |
| port_open_helper(Channel *c, char *rtype) |
| { |
| int direct; |
| char buf[1024]; |
| char *remote_ipaddr = get_peer_ipaddr(c->sock); |
| int remote_port = get_peer_port(c->sock); |
| |
| direct = (strcmp(rtype, "direct-tcpip") == 0); |
| |
| snprintf(buf, sizeof buf, |
| "%s: listening port %d for %.100s port %d, " |
| "connect from %.200s port %d", |
| rtype, c->listening_port, c->path, c->host_port, |
| remote_ipaddr, remote_port); |
| |
| xfree(c->remote_name); |
| c->remote_name = xstrdup(buf); |
| |
| if (compat20) { |
| packet_start(SSH2_MSG_CHANNEL_OPEN); |
| packet_put_cstring(rtype); |
| packet_put_int(c->self); |
| packet_put_int(c->local_window_max); |
| packet_put_int(c->local_maxpacket); |
| if (direct) { |
| /* target host, port */ |
| packet_put_cstring(c->path); |
| packet_put_int(c->host_port); |
| } else { |
| /* listen address, port */ |
| packet_put_cstring(c->path); |
| packet_put_int(c->listening_port); |
| } |
| /* originator host and port */ |
| packet_put_cstring(remote_ipaddr); |
| packet_put_int((u_int)remote_port); |
| packet_send(); |
| } else { |
| packet_start(SSH_MSG_PORT_OPEN); |
| packet_put_int(c->self); |
| packet_put_cstring(c->path); |
| packet_put_int(c->host_port); |
| if (packet_get_protocol_flags() & |
| SSH_PROTOFLAG_HOST_IN_FWD_OPEN) |
| packet_put_cstring(c->remote_name); |
| packet_send(); |
| } |
| xfree(remote_ipaddr); |
| } |
| |
| static void |
| channel_set_reuseaddr(int fd) |
| { |
| int on = 1; |
| |
| /* |
| * Set socket options. |
| * Allow local port reuse in TIME_WAIT. |
| */ |
| if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) |
| error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno)); |
| } |
| |
| /* |
| * This socket is listening for connections to a forwarded TCP/IP port. |
| */ |
| /* ARGSUSED */ |
| static void |
| channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| Channel *nc; |
| struct sockaddr_storage addr; |
| int newsock, nextstate; |
| socklen_t addrlen; |
| char *rtype; |
| |
| if (FD_ISSET(c->sock, readset)) { |
| debug("Connection to port %d forwarding " |
| "to %.100s port %d requested.", |
| c->listening_port, c->path, c->host_port); |
| |
| if (c->type == SSH_CHANNEL_RPORT_LISTENER) { |
| nextstate = SSH_CHANNEL_OPENING; |
| rtype = "forwarded-tcpip"; |
| } else { |
| if (c->host_port == 0) { |
| nextstate = SSH_CHANNEL_DYNAMIC; |
| rtype = "dynamic-tcpip"; |
| } else { |
| nextstate = SSH_CHANNEL_OPENING; |
| rtype = "direct-tcpip"; |
| } |
| } |
| |
| addrlen = sizeof(addr); |
| newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); |
| if (newsock < 0) { |
| error("accept: %.100s", strerror(errno)); |
| return; |
| } |
| set_nodelay(newsock); |
| nc = channel_new(rtype, nextstate, newsock, newsock, -1, |
| c->local_window_max, c->local_maxpacket, 0, rtype, 1); |
| nc->listening_port = c->listening_port; |
| nc->host_port = c->host_port; |
| strlcpy(nc->path, c->path, sizeof(nc->path)); |
| |
| if (nextstate == SSH_CHANNEL_DYNAMIC) { |
| /* |
| * do not call the channel_post handler until |
| * this flag has been reset by a pre-handler. |
| * otherwise the FD_ISSET calls might overflow |
| */ |
| nc->delayed = 1; |
| } else { |
| port_open_helper(nc, rtype); |
| } |
| } |
| } |
| |
| /* |
| * This is the authentication agent socket listening for connections from |
| * clients. |
| */ |
| /* ARGSUSED */ |
| static void |
| channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| Channel *nc; |
| int newsock; |
| struct sockaddr_storage addr; |
| socklen_t addrlen; |
| |
| if (FD_ISSET(c->sock, readset)) { |
| addrlen = sizeof(addr); |
| newsock = accept(c->sock, (struct sockaddr *)&addr, &addrlen); |
| if (newsock < 0) { |
| error("accept from auth socket: %.100s", strerror(errno)); |
| return; |
| } |
| nc = channel_new("accepted auth socket", |
| SSH_CHANNEL_OPENING, newsock, newsock, -1, |
| c->local_window_max, c->local_maxpacket, |
| 0, "accepted auth socket", 1); |
| if (compat20) { |
| packet_start(SSH2_MSG_CHANNEL_OPEN); |
| packet_put_cstring("auth-agent@openssh.com"); |
| packet_put_int(nc->self); |
| packet_put_int(c->local_window_max); |
| packet_put_int(c->local_maxpacket); |
| } else { |
| packet_start(SSH_SMSG_AGENT_OPEN); |
| packet_put_int(nc->self); |
| } |
| packet_send(); |
| } |
| } |
| |
| /* ARGSUSED */ |
| static void |
| channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| int err = 0, sock; |
| socklen_t sz = sizeof(err); |
| |
| if (FD_ISSET(c->sock, writeset)) { |
| if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) { |
| err = errno; |
| error("getsockopt SO_ERROR failed"); |
| } |
| if (err == 0) { |
| debug("channel %d: connected to %s port %d", |
| c->self, c->connect_ctx.host, c->connect_ctx.port); |
| channel_connect_ctx_free(&c->connect_ctx); |
| c->type = SSH_CHANNEL_OPEN; |
| if (compat20) { |
| packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); |
| packet_put_int(c->remote_id); |
| packet_put_int(c->self); |
| packet_put_int(c->local_window); |
| packet_put_int(c->local_maxpacket); |
| } else { |
| packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); |
| packet_put_int(c->remote_id); |
| packet_put_int(c->self); |
| } |
| } else { |
| debug("channel %d: connection failed: %s", |
| c->self, strerror(err)); |
| /* Try next address, if any */ |
| if ((sock = connect_next(&c->connect_ctx)) > 0) { |
| close(c->sock); |
| c->sock = c->rfd = c->wfd = sock; |
| channel_max_fd = channel_find_maxfd(); |
| return; |
| } |
| /* Exhausted all addresses */ |
| error("connect_to %.100s port %d: failed.", |
| c->connect_ctx.host, c->connect_ctx.port); |
| channel_connect_ctx_free(&c->connect_ctx); |
| if (compat20) { |
| packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); |
| packet_put_int(c->remote_id); |
| packet_put_int(SSH2_OPEN_CONNECT_FAILED); |
| if (!(datafellows & SSH_BUG_OPENFAILURE)) { |
| packet_put_cstring(strerror(err)); |
| packet_put_cstring(""); |
| } |
| } else { |
| packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); |
| packet_put_int(c->remote_id); |
| } |
| chan_mark_dead(c); |
| } |
| packet_send(); |
| } |
| } |
| |
| /* ARGSUSED */ |
| static int |
| channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| char buf[CHAN_RBUF]; |
| int len, force; |
| |
| force = c->isatty && c->detach_close && c->istate != CHAN_INPUT_CLOSED; |
| if (c->rfd != -1 && (force || FD_ISSET(c->rfd, readset))) { |
| 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 %d", |
| c->self, c->rfd, len); |
| if (c->type != SSH_CHANNEL_OPEN) { |
| debug2("channel %d: not open", c->self); |
| chan_mark_dead(c); |
| return -1; |
| } else if (compat13) { |
| buffer_clear(&c->output); |
| c->type = SSH_CHANNEL_INPUT_DRAINING; |
| debug2("channel %d: input draining.", c->self); |
| } else { |
| chan_read_failed(c); |
| } |
| return -1; |
| } |
| if (c->input_filter != NULL) { |
| if (c->input_filter(c, buf, len) == -1) { |
| debug2("channel %d: filter stops", c->self); |
| chan_read_failed(c); |
| } |
| } else if (c->datagram) { |
| buffer_put_string(&c->input, buf, len); |
| } else { |
| buffer_append(&c->input, buf, len); |
| } |
| } |
| return 1; |
| } |
| |
| /* ARGSUSED */ |
| static int |
| channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| struct termios tio; |
| u_char *data = NULL, *buf; |
| u_int dlen; |
| int len; |
| |
| /* Send buffered output data to the socket. */ |
| if (c->wfd != -1 && |
| FD_ISSET(c->wfd, writeset) && |
| buffer_len(&c->output) > 0) { |
| if (c->output_filter != NULL) { |
| if ((buf = c->output_filter(c, &data, &dlen)) == NULL) { |
| debug2("channel %d: filter stops", c->self); |
| if (c->type != SSH_CHANNEL_OPEN) |
| chan_mark_dead(c); |
| else |
| chan_write_failed(c); |
| return -1; |
| } |
| } else if (c->datagram) { |
| buf = data = buffer_get_string(&c->output, &dlen); |
| } else { |
| buf = data = buffer_ptr(&c->output); |
| dlen = buffer_len(&c->output); |
| } |
| |
| if (c->datagram) { |
| /* ignore truncated writes, datagrams might get lost */ |
| c->local_consumed += dlen + 4; |
| len = write(c->wfd, buf, dlen); |
| xfree(data); |
| if (len < 0 && (errno == EINTR || errno == EAGAIN || |
| errno == EWOULDBLOCK)) |
| return 1; |
| if (len <= 0) { |
| if (c->type != SSH_CHANNEL_OPEN) |
| chan_mark_dead(c); |
| else |
| chan_write_failed(c); |
| return -1; |
| } |
| return 1; |
| } |
| #ifdef _AIX |
| /* XXX: Later AIX versions can't push as much data to tty */ |
| if (compat20 && 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) { |
| if (c->type != SSH_CHANNEL_OPEN) { |
| debug2("channel %d: not open", c->self); |
| chan_mark_dead(c); |
| return -1; |
| } else if (compat13) { |
| buffer_clear(&c->output); |
| debug2("channel %d: input draining.", c->self); |
| c->type = SSH_CHANNEL_INPUT_DRAINING; |
| } else { |
| chan_write_failed(c); |
| } |
| return -1; |
| } |
| if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') { |
| if (tcgetattr(c->wfd, &tio) == 0 && |
| !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { |
| /* |
| * Simulate echo to reduce the impact of |
| * traffic analysis. We need to match the |
| * size of a SSH2_MSG_CHANNEL_DATA message |
| * (4 byte channel id + buf) |
| */ |
| packet_send_ignore(4 + len); |
| packet_send(); |
| } |
| } |
| buffer_consume(&c->output, len); |
| if (compat20 && len > 0) { |
| c->local_consumed += len; |
| } |
| } |
| return 1; |
| } |
| |
| static int |
| channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| char buf[CHAN_RBUF]; |
| int len; |
| |
| /** XXX handle drain efd, too */ |
| if (c->efd != -1) { |
| if (c->extended_usage == CHAN_EXTENDED_WRITE && |
| FD_ISSET(c->efd, writeset) && |
| buffer_len(&c->extended) > 0) { |
| len = write(c->efd, buffer_ptr(&c->extended), |
| buffer_len(&c->extended)); |
| debug2("channel %d: written %d to efd %d", |
| c->self, len, c->efd); |
| if (len < 0 && (errno == EINTR || errno == EAGAIN || |
| errno == EWOULDBLOCK)) |
| return 1; |
| if (len <= 0) { |
| debug2("channel %d: closing write-efd %d", |
| c->self, c->efd); |
| channel_close_fd(&c->efd); |
| } else { |
| buffer_consume(&c->extended, len); |
| c->local_consumed += len; |
| } |
| } else if (c->extended_usage == CHAN_EXTENDED_READ && |
| (c->detach_close || FD_ISSET(c->efd, readset))) { |
| len = read(c->efd, buf, sizeof(buf)); |
| debug2("channel %d: read %d from efd %d", |
| c->self, len, c->efd); |
| if (len < 0 && (errno == EINTR || ((errno == EAGAIN || |
| errno == EWOULDBLOCK) && !c->detach_close))) |
| return 1; |
| if (len <= 0) { |
| debug2("channel %d: closing read-efd %d", |
| c->self, c->efd); |
| channel_close_fd(&c->efd); |
| } else { |
| buffer_append(&c->extended, buf, len); |
| } |
| } |
| } |
| return 1; |
| } |
| |
| /* ARGSUSED */ |
| static int |
| channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| char buf[16]; |
| int len; |
| |
| /* Monitor control fd to detect if the slave client exits */ |
| if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) { |
| len = read(c->ctl_fd, buf, sizeof(buf)); |
| if (len < 0 && |
| (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)) |
| return 1; |
| if (len <= 0) { |
| debug2("channel %d: ctl read<=0", c->self); |
| if (c->type != SSH_CHANNEL_OPEN) { |
| debug2("channel %d: not open", c->self); |
| chan_mark_dead(c); |
| return -1; |
| } else { |
| chan_read_failed(c); |
| chan_write_failed(c); |
| } |
| return -1; |
| } else |
| fatal("%s: unexpected data on ctl fd", __func__); |
| } |
| return 1; |
| } |
| |
| static int |
| channel_check_window(Channel *c) |
| { |
| if (c->type == SSH_CHANNEL_OPEN && |
| !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && |
| ((c->local_window_max - c->local_window > |
| c->local_maxpacket*3) || |
| c->local_window < c->local_window_max/2) && |
| c->local_consumed > 0) { |
| packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); |
| packet_put_int(c->remote_id); |
| packet_put_int(c->local_consumed); |
| packet_send(); |
| debug2("channel %d: window %d sent adjust %d", |
| c->self, c->local_window, |
| c->local_consumed); |
| c->local_window += c->local_consumed; |
| c->local_consumed = 0; |
| } |
| return 1; |
| } |
| |
| static void |
| channel_post_open(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| if (c->delayed) |
| return; |
| channel_handle_rfd(c, readset, writeset); |
| channel_handle_wfd(c, readset, writeset); |
| if (!compat20) |
| return; |
| channel_handle_efd(c, readset, writeset); |
| channel_handle_ctl(c, readset, writeset); |
| channel_check_window(c); |
| } |
| |
| /* ARGSUSED */ |
| static void |
| channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset) |
| { |
| int len; |
| |
| /* Send buffered output data to the socket. */ |
| if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) { |
| len = write(c->sock, buffer_ptr(&c->output), |
| buffer_len(&c->output)); |
| if (len <= 0) |
| buffer_clear(&c->output); |
| else |
| buffer_consume(&c->output, len); |
| } |
| } |
| |
| static void |
| channel_handler_init_20(void) |
| { |
| channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; |
| channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; |
| channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; |
| channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; |
| channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; |
| channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; |
| channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; |
| channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; |
| |
| channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; |
| channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; |
| channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; |
| channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; |
| channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; |
| channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; |
| channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; |
| } |
| |
| static void |
| channel_handler_init_13(void) |
| { |
| channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13; |
| channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13; |
| channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; |
| channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; |
| channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; |
| channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining; |
| channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining; |
| channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; |
| channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; |
| |
| channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; |
| channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; |
| channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; |
| channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; |
| channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13; |
| channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; |
| channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; |
| } |
| |
| static void |
| channel_handler_init_15(void) |
| { |
| channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; |
| channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; |
| channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; |
| channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; |
| channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; |
| channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; |
| channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; |
| |
| channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; |
| channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; |
| channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; |
| channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; |
| channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; |
| channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; |
| } |
| |
| static void |
| channel_handler_init(void) |
| { |
| int i; |
| |
| for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) { |
| channel_pre[i] = NULL; |
| channel_post[i] = NULL; |
| } |
| if (compat20) |
| channel_handler_init_20(); |
| else if (compat13) |
| channel_handler_init_13(); |
| else |
| channel_handler_init_15(); |
| } |
| |
| /* gc dead channels */ |
| static void |
| channel_garbage_collect(Channel *c) |
| { |
| if (c == NULL) |
| return; |
| if (c->detach_user != NULL) { |
| if (!chan_is_dead(c, c->detach_close)) |
| return; |
| debug2("channel %d: gc: notify user", c->self); |
| c->detach_user(c->self, NULL); |
| /* if we still have a callback */ |
| if (c->detach_user != NULL) |
| return; |
| debug2("channel %d: gc: user detached", c->self); |
| } |
| if (!chan_is_dead(c, 1)) |
| return; |
| debug2("channel %d: garbage collecting", c->self); |
| channel_free(c); |
| } |
| |
| static void |
| channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset) |
| { |
| static int did_init = 0; |
| u_int i; |
| Channel *c; |
| |
| if (!did_init) { |
| channel_handler_init(); |
| did_init = 1; |
| } |
| for (i = 0; i < channels_alloc; i++) { |
| c = channels[i]; |
| if (c == NULL) |
| continue; |
| if (ftab[c->type] != NULL) |
| (*ftab[c->type])(c, readset, writeset); |
| channel_garbage_collect(c); |
| } |
| } |
| |
| /* |
| * Allocate/update select bitmasks and add any bits relevant to channels in |
| * select bitmasks. |
| */ |
| void |
| channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp, |
| u_int *nallocp, int rekeying) |
| { |
| u_int n, sz, nfdset; |
| |
| n = MAX(*maxfdp, channel_max_fd); |
| |
| nfdset = howmany(n+1, NFDBITS); |
| /* Explicitly test here, because xrealloc isn't always called */ |
| if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask)) |
| fatal("channel_prepare_select: max_fd (%d) is too large", n); |
| sz = nfdset * sizeof(fd_mask); |
| |
| /* perhaps check sz < nalloc/2 and shrink? */ |
| if (*readsetp == NULL || sz > *nallocp) { |
| *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask)); |
| *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask)); |
| *nallocp = sz; |
| } |
| *maxfdp = n; |
| memset(*readsetp, 0, sz); |
| memset(*writesetp, 0, sz); |
| |
| if (!rekeying) |
| channel_handler(channel_pre, *readsetp, *writesetp); |
| } |
| |
| /* |
| * After select, perform any appropriate operations for channels which have |
| * events pending. |
| */ |
| void |
| channel_after_select(fd_set *readset, fd_set *writeset) |
| { |
| channel_handler(channel_post, readset, writeset); |
| } |
| |
| |
| /* If there is data to send to the connection, enqueue some of it now. */ |
| void |
| channel_output_poll(void) |
| { |
| Channel *c; |
| u_int i, len; |
| |
| for (i = 0; i < channels_alloc; i++) { |
| c = channels[i]; |
| if (c == NULL) |
| continue; |
| |
| /* |
| * We are only interested in channels that can have buffered |
| * incoming data. |
| */ |
| if (compat13) { |
| if (c->type != SSH_CHANNEL_OPEN && |
| c->type != SSH_CHANNEL_INPUT_DRAINING) |
| continue; |
| } else { |
| if (c->type != SSH_CHANNEL_OPEN) |
| continue; |
| } |
| if (compat20 && |
| (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { |
| /* XXX is this true? */ |
| debug3("channel %d: will not send data after close", c->self); |
| continue; |
| } |
| |
| /* Get the amount of buffered data for this channel. */ |
| if ((c->istate == CHAN_INPUT_OPEN || |
| c->istate == CHAN_INPUT_WAIT_DRAIN) && |
| (len = buffer_len(&c->input)) > 0) { |
| if (c->datagram) { |
| if (len > 0) { |
| u_char *data; |
| u_int dlen; |
| |
| data = buffer_get_string(&c->input, |
| &dlen); |
| packet_start(SSH2_MSG_CHANNEL_DATA); |
| packet_put_int(c->remote_id); |
| packet_put_string(data, dlen); |
| packet_send(); |
| c->remote_window -= dlen + 4; |
| xfree(data); |
| } |
| continue; |
| } |
| /* |
| * Send some data for the other side over the secure |
| * connection. |
| */ |
| if (compat20) { |
| if (len > c->remote_window) |
| len = c->remote_window; |
| if (len > c->remote_maxpacket) |
| len = c->remote_maxpacket; |
| } else { |
| if (packet_is_interactive()) { |
| if (len > 1024) |
| len = 512; |
| } else { |
| /* Keep the packets at reasonable size. */ |
| if (len > packet_get_maxsize()/2) |
| len = packet_get_maxsize()/2; |
| } |
| } |
| if (len > 0) { |
| packet_start(compat20 ? |
| SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA); |
| packet_put_int(c->remote_id); |
| packet_put_string(buffer_ptr(&c->input), len); |
| packet_send(); |
| buffer_consume(&c->input, len); |
| c->remote_window -= len; |
| } |
| } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) { |
| if (compat13) |
| fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3"); |
| /* |
| * input-buffer is empty and read-socket shutdown: |
| * tell peer, that we will not send more data: send IEOF. |
| * hack for extended data: delay EOF if EFD still in use. |
| */ |
| if (CHANNEL_EFD_INPUT_ACTIVE(c)) |
| debug2("channel %d: ibuf_empty delayed efd %d/(%d)", |
| c->self, c->efd, buffer_len(&c->extended)); |
| else |
| chan_ibuf_empty(c); |
| } |
| /* Send extended data, i.e. stderr */ |
| if (compat20 && |
| !(c->flags & CHAN_EOF_SENT) && |
| c->remote_window > 0 && |
| (len = buffer_len(&c->extended)) > 0 && |
| c->extended_usage == CHAN_EXTENDED_READ) { |
| debug2("channel %d: rwin %u elen %u euse %d", |
| c->self, c->remote_window, buffer_len(&c->extended), |
| c->extended_usage); |
| if (len > c->remote_window) |
| len = c->remote_window; |
| if (len > c->remote_maxpacket) |
| len = c->remote_maxpacket; |
| packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA); |
| packet_put_int(c->remote_id); |
| packet_put_int(SSH2_EXTENDED_DATA_STDERR); |
| packet_put_string(buffer_ptr(&c->extended), len); |
| packet_send(); |
| buffer_consume(&c->extended, len); |
| c->remote_window -= len; |
| debug2("channel %d: sent ext data %d", c->self, len); |
| } |
| } |
| } |
| |
| |
| /* -- protocol input */ |
| |
| /* ARGSUSED */ |
| void |
| channel_input_data(int type, u_int32_t seq, void *ctxt) |
| { |
| int id; |
| char *data; |
| u_int data_len; |
| Channel *c; |
| |
| /* Get the channel number and verify it. */ |
| id = packet_get_int(); |
| c = channel_lookup(id); |
| if (c == NULL) |
| packet_disconnect("Received data for nonexistent channel %d.", id); |
| |
| /* Ignore any data for non-open channels (might happen on close) */ |
| if (c->type != SSH_CHANNEL_OPEN && |
| c->type != SSH_CHANNEL_X11_OPEN) |
| return; |
| |
| /* Get the data. */ |
| data = packet_get_string_ptr(&data_len); |
| |
| /* |
| * Ignore data for protocol > 1.3 if output end is no longer open. |
| * For protocol 2 the sending side is reducing its window as it sends |
| * data, so we must 'fake' consumption of the data in order to ensure |
| * that window updates are sent back. Otherwise the connection might |
| * deadlock. |
| */ |
| if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) { |
| if (compat20) { |
| c->local_window -= data_len; |
| c->local_consumed += data_len; |
| } |
| return; |
| } |
| |
| if (compat20) { |
| if (data_len > c->local_maxpacket) { |
| logit("channel %d: rcvd big packet %d, maxpack %d", |
| c->self, data_len, c->local_maxpacket); |
| } |
| if (data_len > c->local_window) { |
| logit("channel %d: rcvd too much data %d, win %d", |
| c->self, data_len, c->local_window); |
| return; |
| } |
| c->local_window -= data_len; |
| } |
| if (c->datagram) |
| buffer_put_string(&c->output, data, data_len); |
| else |
| buffer_append(&c->output, data, data_len); |
| packet_check_eom(); |
| } |
| |
| /* ARGSUSED */ |
| void |
| channel_input_extended_data(int type, u_int32_t seq, void *ctxt) |
| { |
| int id; |
| char *data; |
| u_int data_len, tcode; |
| Channel *c; |
| |
| /* Get the channel number and verify it. */ |
| id = packet_get_int(); |
| c = channel_lookup(id); |
| |
| if (c == NULL) |
| packet_disconnect("Received extended_data for bad channel %d.", id); |
| if (c->type != SSH_CHANNEL_OPEN) { |
| logit("channel %d: ext data for non open", id); |
| return; |
| } |
| if (c->flags & CHAN_EOF_RCVD) { |
| if (datafellows & SSH_BUG_EXTEOF) |
| debug("channel %d: accepting ext data after eof", id); |
| else |
| packet_disconnect("Received extended_data after EOF " |
| "on channel %d.", id); |
| } |
| tcode = packet_get_int(); |
| if (c->efd == -1 || |
| c->extended_usage != CHAN_EXTENDED_WRITE || |
| tcode != SSH2_EXTENDED_DATA_STDERR) { |
| logit("channel %d: bad ext data", c->self); |
| return; |
| } |
| data = packet_get_string(&data_len); |
| packet_check_eom(); |
| if (data_len > c->local_window) { |
| logit("channel %d: rcvd too much extended_data %d, win %d", |
| c->self, data_len, c->local_window); |
| xfree(data); |
| return; |
| } |
| debug2("channel %d: rcvd ext data %d", c->self, data_len); |
| c->local_window -= data_len; |
| buffer_append(&c->extended, data, data_len); |
| xfree(data); |
| } |
| |
| /* ARGSUSED */ |
| void |
| channel_input_ieof(int type, u_int32_t seq, void *ctxt) |
| { |
| int id; |
| Channel *c; |
| |
| id = packet_get_int(); |
| packet_check_eom(); |
| c = channel_lookup(id); |
| if (c == NULL) |
| packet_disconnect("Received ieof for nonexistent channel %d.", id); |
| chan_rcvd_ieof(c); |
| |
| /* XXX force input close */ |
| if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { |
| debug("channel %d: FORCE input drain", c->self); |
| c->istate = CHAN_INPUT_WAIT_DRAIN; |
| if (buffer_len(&c->input) == 0) |
| chan_ibuf_empty(c); |
| } |
| |
| } |
| |
| /* ARGSUSED */ |
| void |
| channel_input_close(int type, u_int32_t seq, void *ctxt) |
| { |
| int id; |
| Channel *c; |
| |
| id = packet_get_int(); |
| packet_check_eom(); |
| c = channel_lookup(id); |
| if (c == NULL) |
| packet_disconnect("Received close for nonexistent channel %d.", id); |
| |
| /* |
| * Send a confirmation that we have closed the channel and no more |
| * data is coming for it. |
| */ |
| packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION); |
| packet_put_int(c->remote_id); |
| packet_send(); |
| |
| /* |
| * If the channel is in closed state, we have sent a close request, |
| * and the other side will eventually respond with a confirmation. |
| * Thus, we cannot free the channel here, because then there would be |
| * no-one to receive the confirmation. The channel gets freed when |
| * the confirmation arrives. |
| */ |
| if (c->type != SSH_CHANNEL_CLOSED) { |
| /* |
| * Not a closed channel - mark it as draining, which will |
| * cause it to be freed later. |
| */ |
| buffer_clear(&c->input); |
| c->type = SSH_CHANNEL_OUTPUT_DRAINING; |
| } |
| } |
| |
| /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ |
| /* ARGSUSED */ |
| void |
| channel_input_oclose(int type, u_int32_t seq, void *ctxt) |
| { |
| int id = packet_get_int(); |
| Channel *c = channel_lookup(id); |
| |
| packet_check_eom(); |
| if (c == NULL) |
| packet_disconnect("Received oclose for nonexistent channel %d.", id); |
| chan_rcvd_oclose(c); |
| } |
| |
| /* ARGSUSED */ |
| void |
| channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt) |
| { |
| int id = packet_get_int(); |
| Channel *c = channel_lookup(id); |
| |
| packet_check_eom(); |
| if (c == NULL) |
| packet_disconnect("Received close confirmation for " |
| "out-of-range channel %d.", id); |
| if (c->type != SSH_CHANNEL_CLOSED) |
| packet_disconnect("Received close confirmation for " |
| "non-closed channel %d (type %d).", id, c->type); |
| channel_free(c); |
| } |
| |
| /* ARGSUSED */ |
| void |
| channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt) |
| { |
| int id, remote_id; |
| Channel *c; |
| |
| id = packet_get_int(); |
| c = channel_lookup(id); |
| |
| if (c==NULL || c->type != SSH_CHANNEL_OPENING) |
| packet_disconnect("Received open confirmation for " |
| "non-opening channel %d.", id); |
| remote_id = packet_get_int(); |
| /* Record the remote channel number and mark that the channel is now open. */ |
| c->remote_id = remote_id; |
| c->type = SSH_CHANNEL_OPEN; |
| |
| if (compat20) { |
| c->remote_window = packet_get_int(); |
| c->remote_maxpacket = packet_get_int(); |
| if (c->open_confirm) { |
| debug2("callback start"); |
| c->open_confirm(c->self, c->open_confirm_ctx); |
| debug2("callback done"); |
| } |
| debug2("channel %d: open confirm rwindow %u rmax %u", c->self, |
| c->remote_window, c->remote_maxpacket); |
| } |
| packet_check_eom(); |
| } |
| |
| static char * |
| reason2txt(int reason) |
| { |
| switch (reason) { |
| case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: |
| return "administratively prohibited"; |
| case SSH2_OPEN_CONNECT_FAILED: |
| return "connect failed"; |
| case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: |
| return "unknown channel type"; |
| case SSH2_OPEN_RESOURCE_SHORTAGE: |
| return "resource shortage"; |
| } |
| return "unknown reason"; |
| } |
| |
| /* ARGSUSED */ |
| void |
| channel_input_open_failure(int type, u_int32_t seq, void *ctxt) |
| { |
| int id, reason; |
| char *msg = NULL, *lang = NULL; |
| Channel *c; |
| |
| id = packet_get_int(); |
| c = channel_lookup(id); |
| |
| if (c==NULL || c->type != SSH_CHANNEL_OPENING) |
| packet_disconnect("Received open failure for " |
| "non-opening channel %d.", id); |
| if (compat20) { |
| reason = packet_get_int(); |
| if (!(datafellows & SSH_BUG_OPENFAILURE)) { |
| msg = packet_get_string(NULL); |
| lang = packet_get_string(NULL); |
| } |
| logit("channel %d: open failed: %s%s%s", id, |
| reason2txt(reason), msg ? ": ": "", msg ? msg : ""); |
| if (msg != NULL) |
| xfree(msg); |
| if (lang != NULL) |
| xfree(lang); |
| } |
| packet_check_eom(); |
| /* Free the channel. This will also close the socket. */ |
| channel_free(c); |
| } |
| |
| /* ARGSUSED */ |
| void |
| channel_input_window_adjust(int type, u_int32_t seq, void *ctxt) |
| { |
| Channel *c; |
| int id; |
| u_int adjust; |
| |
| if (!compat20) |
| return; |
| |
| /* Get the channel number and verify it. */ |
| id = packet_get_int(); |
| c = channel_lookup(id); |
| |
| if (c == NULL) { |
| logit("Received window adjust for non-open channel %d.", id); |
| return; |
| } |
| adjust = packet_get_int(); |
| packet_check_eom(); |
| debug2("channel %d: rcvd adjust %u", id, adjust); |
| c->remote_window += adjust; |
| } |
| |
| /* ARGSUSED */ |
| void |
| channel_input_port_open(int type, u_int32_t seq, void *ctxt) |
| { |
| Channel *c = NULL; |
| u_short host_port; |
| char *host, *originator_string; |
| int remote_id; |
| |
| remote_id = packet_get_int(); |
| host = packet_get_string(NULL); |
| host_port = packet_get_int(); |
| |
| if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { |
| originator_string = packet_get_string(NULL); |
| } else { |
| originator_string = xstrdup("unknown (remote did not supply name)"); |
| } |
| packet_check_eom(); |
| c = channel_connect_to(host, host_port, |
| "connected socket", originator_string); |
| xfree(originator_string); |
| xfree(host); |
| if (c == NULL) { |
| packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); |
| packet_put_int(remote_id); |
| packet_send(); |
| } else |
| c->remote_id = remote_id; |
| } |
| |
| /* ARGSUSED */ |
| void |
| channel_input_status_confirm(int type, u_int32_t seq, void *ctxt) |
| { |
| Channel *c; |
| struct channel_confirm *cc; |
| int remote_id; |
| |
| /* Reset keepalive timeout */ |
| keep_alive_timeouts = 0; |
| |
| remote_id = packet_get_int(); |
| packet_check_eom(); |
| |
| debug2("channel_input_confirm: type %d id %d", type, remote_id); |
| |
| if ((c = channel_lookup(remote_id)) == NULL) { |
| logit("channel_input_success_failure: %d: unknown", remote_id); |
| return; |
| } |
| ; |
| if ((cc = TAILQ_FIRST(&c->status_confirms)) == NULL) |
| return; |
| cc->cb(type, c, cc->ctx); |
| TAILQ_REMOVE(&c->status_confirms, cc, entry); |
| bzero(cc, sizeof(*cc)); |
| xfree(cc); |
| } |
| |
| /* -- tcp forwarding */ |
| |
| void |
| channel_set_af(int af) |
| { |
| IPv4or6 = af; |
| } |
| |
| static int |
| channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port, |
| const char *host_to_connect, u_short port_to_connect, int gateway_ports) |
| { |
| Channel *c; |
| int sock, r, success = 0, wildcard = 0, is_client; |
| struct addrinfo hints, *ai, *aitop; |
| const char *host, *addr; |
| char ntop[NI_MAXHOST], strport[NI_MAXSERV]; |
| |
| host = (type == SSH_CHANNEL_RPORT_LISTENER) ? |
| listen_addr : host_to_connect; |
| is_client = (type == SSH_CHANNEL_PORT_LISTENER); |
| |
| if (host == NULL) { |
| error("No forward host name."); |
| return 0; |
| } |
| if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) { |
| error("Forward host name too long."); |
| return 0; |
| } |
| |
| /* |
| * Determine whether or not a port forward listens to loopback, |
| * specified address or wildcard. On the client, a specified bind |
| * address will always override gateway_ports. On the server, a |
| * gateway_ports of 1 (``yes'') will override the client's |
| * specification and force a wildcard bind, whereas a value of 2 |
| * (``clientspecified'') will bind to whatever address the client |
| * asked for. |
| * |
| * Special-case listen_addrs are: |
| * |
| * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR |
| * "" (empty string), "*" -> wildcard v4/v6 |
| * "localhost" -> loopback v4/v6 |
| */ |
| addr = NULL; |
| if (listen_addr == NULL) { |
| /* No address specified: default to gateway_ports setting */ |
| if (gateway_ports) |
| wildcard = 1; |
| } else if (gateway_ports || is_client) { |
| if (((datafellows & SSH_OLD_FORWARD_ADDR) && |
| strcmp(listen_addr, "0.0.0.0") == 0 && is_client == 0) || |
| *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || |
| (!is_client && gateway_ports == 1)) |
| wildcard = 1; |
| else if (strcmp(listen_addr, "localhost") != 0) |
| addr = listen_addr; |
| } |
| |
| debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s", |
| type, wildcard, (addr == NULL) ? "NULL" : addr); |
| |
| /* |
| * getaddrinfo returns a loopback address if the hostname is |
| * set to NULL and hints.ai_flags is not AI_PASSIVE |
| */ |
| memset(&hints, 0, sizeof(hints)); |
| hints.ai_family = IPv4or6; |
| hints.ai_flags = wildcard ? AI_PASSIVE : 0; |
| hints.ai_socktype = SOCK_STREAM; |
| snprintf(strport, sizeof strport, "%d", listen_port); |
| if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { |
| if (addr == NULL) { |
| /* This really shouldn't happen */ |
| packet_disconnect("getaddrinfo: fatal error: %s", |
| ssh_gai_strerror(r)); |
| } else { |
| error("channel_setup_fwd_listener: " |
| "getaddrinfo(%.64s): %s", addr, |
| ssh_gai_strerror(r)); |
| } |
| return 0; |
| } |
| |
| for (ai = aitop; ai; ai = ai->ai_next) { |
| if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) |
| continue; |
| if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), |
| strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { |
| error("channel_setup_fwd_listener: getnameinfo failed"); |
| continue; |
| } |
| /* Create a port to listen for the host. */ |
| sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); |
| if (sock < 0) { |
| /* this is no error since kernel may not support ipv6 */ |
| verbose("socket: %.100s", strerror(errno)); |
| continue; |
| } |
| |
| channel_set_reuseaddr(sock); |
| |
| debug("Local forwarding listening on %s port %s.", ntop, strport); |
| |
| /* Bind the socket to the address. */ |
| if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { |
| /* address can be in use ipv6 address is already bound */ |
| if (!ai->ai_next) |
| error("bind: %.100s", strerror(errno)); |
| else |
| verbose("bind: %.100s", strerror(errno)); |
| |
| close(sock); |
| continue; |
| } |
| /* Start listening for connections on the socket. */ |
| if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { |
| error("listen: %.100s", strerror(errno)); |
| close(sock); |
| continue; |
| } |
| /* Allocate a channel number for the socket. */ |
| c = channel_new("port listener", type, sock, sock, -1, |
| CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, |
| 0, "port listener", 1); |
| strlcpy(c->path, host, sizeof(c->path)); |
| c->host_port = port_to_connect; |
| c->listening_port = listen_port; |
| success = 1; |
| } |
| if (success == 0) |
| error("channel_setup_fwd_listener: cannot listen to port: %d", |
| listen_port); |
| freeaddrinfo(aitop); |
| return success; |
| } |
| |
| int |
| channel_cancel_rport_listener(const char *host, u_short port) |
| { |
| u_int i; |
| int found = 0; |
| |
| for (i = 0; i < channels_alloc; i++) { |
| Channel *c = channels[i]; |
| |
| if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER && |
| strncmp(c->path, host, sizeof(c->path)) == 0 && |
| c->listening_port == port) { |
| debug2("%s: close channel %d", __func__, i); |
| channel_free(c); |
| found = 1; |
| } |
| } |
| |
| return (found); |
| } |
| |
| /* protocol local port fwd, used by ssh (and sshd in v1) */ |
| int |
| channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port, |
| const char *host_to_connect, u_short port_to_connect, int gateway_ports) |
| { |
| return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER, |
| listen_host, listen_port, host_to_connect, port_to_connect, |
| gateway_ports); |
| } |
| |
| /* protocol v2 remote port fwd, used by sshd */ |
| int |
| channel_setup_remote_fwd_listener(const char *listen_address, |
| u_short listen_port, int gateway_ports) |
| { |
| return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER, |
| listen_address, listen_port, NULL, 0, gateway_ports); |
| } |
| |
| /* |
| * Initiate forwarding of connections to port "port" on remote host through |
| * the secure channel to host:port from local side. |
| */ |
| |
| int |
| channel_request_remote_forwarding(const char *listen_host, u_short listen_port, |
| const char *host_to_connect, u_short port_to_connect) |
| { |
| int type, success = 0; |
| |
| /* Record locally that connection to this host/port is permitted. */ |
| if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) |
| fatal("channel_request_remote_forwarding: too many forwards"); |
| |
| /* Send the forward request to the remote side. */ |
| if (compat20) { |
| const char *address_to_bind; |
| if (listen_host == NULL) { |
| if (datafellows & SSH_BUG_RFWD_ADDR) |
| address_to_bind = "127.0.0.1"; |
| else |
| address_to_bind = "localhost"; |
| } else if (*listen_host == '\0' || |
| strcmp(listen_host, "*") == 0) { |
| if (datafellows & SSH_BUG_RFWD_ADDR) |
| address_to_bind = "0.0.0.0"; |
| else |
| address_to_bind = ""; |
| } else |
| address_to_bind = listen_host; |
| |
| packet_start(SSH2_MSG_GLOBAL_REQUEST); |
| packet_put_cstring("tcpip-forward"); |
| packet_put_char(1); /* boolean: want reply */ |
| packet_put_cstring(address_to_bind); |
| packet_put_int(listen_port); |
| packet_send(); |
| packet_write_wait(); |
| /* Assume that server accepts the request */ |
| success = 1; |
| } else { |
| packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); |
| packet_put_int(listen_port); |
| packet_put_cstring(host_to_connect); |
| packet_put_int(port_to_connect); |
| packet_send(); |
| packet_write_wait(); |
| |
| /* Wait for response from the remote side. */ |
| type = packet_read(); |
| switch (type) { |
| case SSH_SMSG_SUCCESS: |
| success = 1; |
| break; |
| case SSH_SMSG_FAILURE: |
| break; |
| default: |
| /* Unknown packet */ |
| packet_disconnect("Protocol error for port forward request:" |
| "received packet type %d.", type); |
| } |
| } |
| if (success) { |
| permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect); |
| permitted_opens[num_permitted_opens].port_to_connect = port_to_connect; |
| permitted_opens[num_permitted_opens].listen_port = listen_port; |
| num_permitted_opens++; |
| } |
| return (success ? 0 : -1); |
| } |
| |
| /* |
| * Request cancellation of remote forwarding of connection host:port from |
| * local side. |
| */ |
| void |
| channel_request_rforward_cancel(const char *host, u_short port) |
| { |
| int i; |
| |
| if (!compat20) |
| return; |
| |
| for (i = 0; i < num_permitted_opens; i++) { |
| if (permitted_opens[i].host_to_connect != NULL && |
| permitted_opens[i].listen_port == port) |
| break; |
| } |
| if (i >= num_permitted_opens) { |
| debug("%s: requested forward not found", __func__); |
| return; |
| } |
| packet_start(SSH2_MSG_GLOBAL_REQUEST); |
| packet_put_cstring("cancel-tcpip-forward"); |
| packet_put_char(0); |
| packet_put_cstring(host == NULL ? "" : host); |
| packet_put_int(port); |
| packet_send(); |
| |
| permitted_opens[i].listen_port = 0; |
| permitted_opens[i].port_to_connect = 0; |
| xfree(permitted_opens[i].host_to_connect); |
| permitted_opens[i].host_to_connect = NULL; |
| } |
| |
| /* |
| * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates |
| * listening for the port, and sends back a success reply (or disconnect |
| * message if there was an error). |
| */ |
| int |
| channel_input_port_forward_request(int is_root, int gateway_ports) |
| { |
| u_short port, host_port; |
| int success = 0; |
| char *hostname; |
| |
| /* Get arguments from the packet. */ |
| port = packet_get_int(); |
| hostname = packet_get_string(NULL); |
| host_port = packet_get_int(); |
| |
| #ifndef HAVE_CYGWIN |
| /* |
| * Check that an unprivileged user is not trying to forward a |
| * privileged port. |
| */ |
| if (port < IPPORT_RESERVED && !is_root) |
| packet_disconnect( |
| "Requested forwarding of port %d but user is not root.", |
| port); |
| if (host_port == 0) |
| packet_disconnect("Dynamic forwarding denied."); |
| #endif |
| |
| /* Initiate forwarding */ |
| success = channel_setup_local_fwd_listener(NULL, port, hostname, |
| host_port, gateway_ports); |
| |
| /* Free the argument string. */ |
| xfree(hostname); |
| |
| return (success ? 0 : -1); |
| } |
| |
| /* |
| * Permits opening to any host/port if permitted_opens[] is empty. This is |
| * usually called by the server, because the user could connect to any port |
| * anyway, and the server has no way to know but to trust the client anyway. |
| */ |
| void |
| channel_permit_all_opens(void) |
| { |
| if (num_permitted_opens == 0) |
| all_opens_permitted = 1; |
| } |
| |
| void |
| channel_add_permitted_opens(char *host, int port) |
| { |
| if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) |
| fatal("channel_add_permitted_opens: too many forwards"); |
| debug("allow port forwarding to host %s port %d", host, port); |
| |
| permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host); |
| permitted_opens[num_permitted_opens].port_to_connect = port; |
| num_permitted_opens++; |
| |
| all_opens_permitted = 0; |
| } |
| |
| int |
| channel_add_adm_permitted_opens(char *host, int port) |
| { |
| if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) |
| fatal("channel_add_adm_permitted_opens: too many forwards"); |
| debug("config allows port forwarding to host %s port %d", host, port); |
| |
| permitted_adm_opens[num_adm_permitted_opens].host_to_connect |
| = xstrdup(host); |
| permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port; |
| return ++num_adm_permitted_opens; |
| } |
| |
| void |
| channel_clear_permitted_opens(void) |
| { |
| int i; |
| |
| for (i = 0; i < num_permitted_opens; i++) |
| if (permitted_opens[i].host_to_connect != NULL) |
| xfree(permitted_opens[i].host_to_connect); |
| num_permitted_opens = 0; |
| } |
| |
| void |
| channel_clear_adm_permitted_opens(void) |
| { |
| int i; |
| |
| for (i = 0; i < num_adm_permitted_opens; i++) |
| if (permitted_adm_opens[i].host_to_connect != NULL) |
| xfree(permitted_adm_opens[i].host_to_connect); |
| num_adm_permitted_opens = 0; |
| } |
| |
| void |
| channel_print_adm_permitted_opens(void) |
| { |
| static int i; |
| |
| for (i = 0; i < num_adm_permitted_opens; i++) |
| if (permitted_adm_opens[i].host_to_connect != NULL) |
| printf(" %s:%d", permitted_adm_opens[i].host_to_connect, |
| permitted_adm_opens[i].port_to_connect); |
| } |
| |
| /* Try to start non-blocking connect to next host in cctx list */ |
| static int |
| connect_next(struct channel_connect *cctx) |
| { |
| int sock, saved_errno; |
| char ntop[NI_MAXHOST], strport[NI_MAXSERV]; |
| |
| for (; cctx->ai; cctx->ai = cctx->ai->ai_next) { |
| if (cctx->ai->ai_family != AF_INET && |
| cctx->ai->ai_family != AF_INET6) |
| continue; |
| if (getnameinfo(cctx->ai->ai_addr, cctx->ai->ai_addrlen, |
| ntop, sizeof(ntop), strport, sizeof(strport), |
| NI_NUMERICHOST|NI_NUMERICSERV) != 0) { |
| error("connect_next: getnameinfo failed"); |
| continue; |
| } |
| if ((sock = socket(cctx->ai->ai_family, cctx->ai->ai_socktype, |
| cctx->ai->ai_protocol)) == -1) { |
| if (cctx->ai->ai_next == NULL) |
| error("socket: %.100s", strerror(errno)); |
| else |
| verbose("socket: %.100s", strerror(errno)); |
| continue; |
| } |
| if (set_nonblock(sock) == -1) |
| fatal("%s: set_nonblock(%d)", __func__, sock); |
| if (connect(sock, cctx->ai->ai_addr, |
| cctx->ai->ai_addrlen) == -1 && errno != EINPROGRESS) { |
| debug("connect_next: host %.100s ([%.100s]:%s): " |
| "%.100s", cctx->host, ntop, strport, |
| strerror(errno)); |
| saved_errno = errno; |
| close(sock); |
| errno = saved_errno; |
| continue; /* fail -- try next */ |
| } |
| debug("connect_next: host %.100s ([%.100s]:%s) " |
| "in progress, fd=%d", cctx->host, ntop, strport, sock); |
| cctx->ai = cctx->ai->ai_next; |
| set_nodelay(sock); |
| return sock; |
| } |
| return -1; |
| } |
| |
| static void |
| channel_connect_ctx_free(struct channel_connect *cctx) |
| { |
| xfree(cctx->host); |
| if (cctx->aitop) |
| freeaddrinfo(cctx->aitop); |
| bzero(cctx, sizeof(*cctx)); |
| cctx->host = NULL; |
| cctx->ai = cctx->aitop = NULL; |
| } |
| |
| /* Return CONNECTING channel to remote host, port */ |
| static Channel * |
| connect_to(const char *host, u_short port, char *ctype, char *rname) |
| { |
| struct addrinfo hints; |
| int gaierr; |
| int sock = -1; |
| char strport[NI_MAXSERV]; |
| struct channel_connect cctx; |
| Channel *c; |
| |
| memset(&cctx, 0, sizeof(cctx)); |
| memset(&hints, 0, sizeof(hints)); |
| hints.ai_family = IPv4or6; |
| hints.ai_socktype = SOCK_STREAM; |
| snprintf(strport, sizeof strport, "%d", port); |
| if ((gaierr = getaddrinfo(host, strport, &hints, &cctx.aitop)) != 0) { |
| error("connect_to %.100s: unknown host (%s)", host, |
| ssh_gai_strerror(gaierr)); |
| return NULL; |
| } |
| |
| cctx.host = xstrdup(host); |
| cctx.port = port; |
| cctx.ai = cctx.aitop; |
| |
| if ((sock = connect_next(&cctx)) == -1) { |
| error("connect to %.100s port %d failed: %s", |
| host, port, strerror(errno)); |
| channel_connect_ctx_free(&cctx); |
| return NULL; |
| } |
| c = channel_new(ctype, SSH_CHANNEL_CONNECTING, sock, sock, -1, |
| CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, rname, 1); |
| c->connect_ctx = cctx; |
| return c; |
| } |
| |
| Channel * |
| channel_connect_by_listen_address(u_short listen_port, char *ctype, char *rname) |
| { |
| int i; |
| |
| for (i = 0; i < num_permitted_opens; i++) { |
| if (permitted_opens[i].host_to_connect != NULL && |
| permitted_opens[i].listen_port == listen_port) { |
| return connect_to( |
| permitted_opens[i].host_to_connect, |
| permitted_opens[i].port_to_connect, ctype, rname); |
| } |
| } |
| error("WARNING: Server requests forwarding for unknown listen_port %d", |
| listen_port); |
| return NULL; |
| } |
| |
| /* Check if connecting to that port is permitted and connect. */ |
| Channel * |
| channel_connect_to(const char *host, u_short port, char *ctype, char *rname) |
| { |
| int i, permit, permit_adm = 1; |
| |
| permit = all_opens_permitted; |
| if (!permit) { |
| for (i = 0; i < num_permitted_opens; i++) |
| if (permitted_opens[i].host_to_connect != NULL && |
| permitted_opens[i].port_to_connect == port && |
| strcmp(permitted_opens[i].host_to_connect, host) == 0) |
| permit = 1; |
| } |
| |
| if (num_adm_permitted_opens > 0) { |
| permit_adm = 0; |
| for (i = 0; i < num_adm_permitted_opens; i++) |
| if (permitted_adm_opens[i].host_to_connect != NULL && |
| permitted_adm_opens[i].port_to_connect == port && |
| strcmp(permitted_adm_opens[i].host_to_connect, host) |
| == 0) |
| permit_adm = 1; |
| } |
| |
| if (!permit || !permit_adm) { |
| logit("Received request to connect to host %.100s port %d, " |
| "but the request was denied.", host, port); |
| return NULL; |
| } |
| return connect_to(host, port, ctype, rname); |
| } |
| |
| void |
| channel_send_window_changes(void) |
| { |
| u_int i; |
| struct winsize ws; |
| |
| for (i = 0; i < channels_alloc; i++) { |
| if (channels[i] == NULL || !channels[i]->client_tty || |
| channels[i]->type != SSH_CHANNEL_OPEN) |
| continue; |
| if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0) |
| continue; |
| channel_request_start(i, "window-change", 0); |
| packet_put_int((u_int)ws.ws_col); |
| packet_put_int((u_int)ws.ws_row); |
| packet_put_int((u_int)ws.ws_xpixel); |
| packet_put_int((u_int)ws.ws_ypixel); |
| packet_send(); |
| } |
| } |
| |
| /* -- X11 forwarding */ |
| |
| /* |
| * Creates an internet domain socket for listening for X11 connections. |
| * Returns 0 and a suitable display number for the DISPLAY variable |
| * stored in display_numberp , or -1 if an error occurs. |
| */ |
| int |
| x11_create_display_inet(int x11_display_offset, int x11_use_localhost, |
| int single_connection, u_int *display_numberp, int **chanids) |
| { |
| Channel *nc = NULL; |
| int display_number, sock; |
| u_short port; |
| struct addrinfo hints, *ai, *aitop; |
| char strport[NI_MAXSERV]; |
| int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; |
| |
| if (chanids == NULL) |
| return -1; |
| |
| for (display_number = x11_display_offset; |
| display_number < MAX_DISPLAYS; |
| display_number++) { |
| port = 6000 + display_number; |
| memset(&hints, 0, sizeof(hints)); |
| hints.ai_family = IPv4or6; |
| hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; |
| hints.ai_socktype = SOCK_STREAM; |
| snprintf(strport, sizeof strport, "%d", port); |
| if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) { |
| error("getaddrinfo: %.100s", ssh_gai_strerror(gaierr)); |
| return -1; |
| } |
| for (ai = aitop; ai; ai = ai->ai_next) { |
| if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) |
| continue; |
| sock = socket(ai->ai_family, ai->ai_socktype, |
| ai->ai_protocol); |
| if (sock < 0) { |
| if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) { |
| error("socket: %.100s", strerror(errno)); |
| freeaddrinfo(aitop); |
| return -1; |
| } else { |
| debug("x11_create_display_inet: Socket family %d not supported", |
| ai->ai_family); |
| continue; |
| } |
| } |
| #ifdef IPV6_V6ONLY |
| if (ai->ai_family == AF_INET6) { |
| int on = 1; |
| if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0) |
| error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno)); |
| } |
| #endif |
| if (x11_use_localhost) |
| channel_set_reuseaddr(sock); |
| if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { |
| debug2("bind port %d: %.100s", port, strerror(errno)); |
| close(sock); |
| |
| for (n = 0; n < num_socks; n++) { |
| close(socks[n]); |
| } |
| num_socks = 0; |
| break; |
| } |
| socks[num_socks++] = sock; |
| if (num_socks == NUM_SOCKS) |
| break; |
| } |
| freeaddrinfo(aitop); |
| if (num_socks > 0) |
| break; |
| } |
| if (display_number >= MAX_DISPLAYS) { |
| error("Failed to allocate internet-domain X11 display socket."); |
| return -1; |
| } |
| /* Start listening for connections on the socket. */ |
| for (n = 0; n < num_socks; n++) { |
| sock = socks[n]; |
| if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { |
| error("listen: %.100s", strerror(errno)); |
| close(sock); |
| return -1; |
| } |
| } |
| |
| /* Allocate a channel for each socket. */ |
| *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); |
| for (n = 0; n < num_socks; n++) { |
| sock = socks[n]; |
| nc = channel_new("x11 listener", |
| SSH_CHANNEL_X11_LISTENER, sock, sock, -1, |
| CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, |
| 0, "X11 inet listener", 1); |
| nc->single_connection = single_connection; |
| (*chanids)[n] = nc->self; |
| } |
| (*chanids)[n] = -1; |
| |
| /* Return the display number for the DISPLAY environment variable. */ |
| *display_numberp = display_number; |
| return (0); |
| } |
| |
| static int |
| connect_local_xsocket(u_int dnr) |
| { |
| int sock; |
| struct sockaddr_un addr; |
| |
| sock = socket(AF_UNIX, SOCK_STREAM, 0); |
| if (sock < 0) |
| error("socket: %.100s", strerror(errno)); |
| memset(&addr, 0, sizeof(addr)); |
| addr.sun_family = AF_UNIX; |
| snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); |
| if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) |
| return sock; |
| close(sock); |
| error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); |
| return -1; |
| } |
| |
| int |
| x11_connect_display(void) |
| { |
| u_int display_number; |
| const char *display; |
| char buf[1024], *cp; |
| struct addrinfo hints, *ai, *aitop; |
| char strport[NI_MAXSERV]; |
| int gaierr, sock = 0; |
| |
| /* Try to open a socket for the local X server. */ |
| display = getenv("DISPLAY"); |
| if (!display) { |
| error("DISPLAY not set."); |
| return -1; |
| } |
| /* |
| * Now we decode the value of the DISPLAY variable and make a |
| * connection to the real X server. |
| */ |
| |
| /* |
| * Check if it is a unix domain socket. Unix domain displays are in |
| * one of the following formats: unix:d[.s], :d[.s], ::d[.s] |
| */ |
| if (strncmp(display, "unix:", 5) == 0 || |
| display[0] == ':') { |
| /* Connect to the unix domain socket. */ |
| if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) { |
| error("Could not parse display number from DISPLAY: %.100s", |
| display); |
| return -1; |
| } |
| /* Create a socket. */ |
| sock = connect_local_xsocket(display_number); |
| if (sock < 0) |
| return -1; |
| |
| /* OK, we now have a connection to the display. */ |
| return sock; |
| } |
| /* |
| * Connect to an inet socket. The DISPLAY value is supposedly |
| * hostname:d[.s], where hostname may also be numeric IP address. |
| */ |
| strlcpy(buf, display, sizeof(buf)); |
| cp = strchr(buf, ':'); |
| if (!cp) { |
| error("Could not find ':' in DISPLAY: %.100s", display); |
| return -1; |
| } |
| *cp = 0; |
| /* buf now contains the host name. But first we parse the display number. */ |
| if (sscanf(cp + 1, "%u", &display_number) != 1) { |
| error("Could not parse display number from DISPLAY: %.100s", |
| display); |
| return -1; |
| } |
| |
| /* Look up the host address */ |
| memset(&hints, 0, sizeof(hints)); |
| hints.ai_family = IPv4or6; |
| hints.ai_socktype = SOCK_STREAM; |
| snprintf(strport, sizeof strport, "%u", 6000 + display_number); |
| if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { |
| error("%.100s: unknown host. (%s)", buf, |
| ssh_gai_strerror(gaierr)); |
| return -1; |
| } |
| for (ai = aitop; ai; ai = ai->ai_next) { |
| /* Create a socket. */ |
| sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); |
| if (sock < 0) { |
| debug2("socket: %.100s", strerror(errno)); |
| continue; |
| } |
| /* Connect it to the display. */ |
| if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { |
| debug2("connect %.100s port %u: %.100s", buf, |
| 6000 + display_number, strerror(errno)); |
| close(sock); |
| continue; |
| } |
| /* Success */ |
| break; |
| } |
| freeaddrinfo(aitop); |
| if (!ai) { |
| error("connect %.100s port %u: %.100s", buf, 6000 + display_number, |
| strerror(errno)); |
| return -1; |
| } |
| set_nodelay(sock); |
| return sock; |
| } |
| |
| /* |
| * This is called when SSH_SMSG_X11_OPEN is received. The packet contains |
| * the remote channel number. We should do whatever we want, and respond |
| * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. |
| */ |
| |
| /* ARGSUSED */ |
| void |
| x11_input_open(int type, u_int32_t seq, void *ctxt) |
| { |
| Channel *c = NULL; |
| int remote_id, sock = 0; |
| char *remote_host; |
| |
| debug("Received X11 open request."); |
| |
| remote_id = packet_get_int(); |
| |
| if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { |
| remote_host = packet_get_string(NULL); |
| } else { |
| remote_host = xstrdup("unknown (remote did not supply name)"); |
| } |
| packet_check_eom(); |
| |
| /* Obtain a connection to the real X display. */ |
| sock = x11_connect_display(); |
| if (sock != -1) { |
| /* Allocate a channel for this connection. */ |
| c = channel_new("connected x11 socket", |
| SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0, |
| remote_host, 1); |
| c->remote_id = remote_id; |
| c->force_drain = 1; |
| } |
| xfree(remote_host); |
| if (c == NULL) { |
| /* Send refusal to the remote host. */ |
| packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); |
| packet_put_int(remote_id); |
| } else { |
| /* Send a confirmation to the remote host. */ |
| packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); |
| packet_put_int(remote_id); |
| packet_put_int(c->self); |
| } |
| packet_send(); |
| } |
| |
| /* dummy protocol handler that denies SSH-1 requests (agent/x11) */ |
| /* ARGSUSED */ |
| void |
| deny_input_open(int type, u_int32_t seq, void *ctxt) |
| { |
| int rchan = packet_get_int(); |
| |
| switch (type) { |
| case SSH_SMSG_AGENT_OPEN: |
| error("Warning: ssh server tried agent forwarding."); |
| break; |
| case SSH_SMSG_X11_OPEN: |
| error("Warning: ssh server tried X11 forwarding."); |
| break; |
| default: |
| error("deny_input_open: type %d", type); |
| break; |
| } |
| error("Warning: this is probably a break-in attempt by a malicious server."); |
| packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); |
| packet_put_int(rchan); |
| packet_send(); |
| } |
| |
| /* |
| * Requests forwarding of X11 connections, generates fake authentication |
| * data, and enables authentication spoofing. |
| * This should be called in the client only. |
| */ |
| void |
| x11_request_forwarding_with_spoofing(int client_session_id, const char *disp, |
| const char *proto, const char *data) |
| { |
| u_int data_len = (u_int) strlen(data) / 2; |
| u_int i, value; |
| char *new_data; |
| int screen_number; |
| const char *cp; |
| u_int32_t rnd = 0; |
| |
| if (x11_saved_display == NULL) |
| x11_saved_display = xstrdup(disp); |
| else if (strcmp(disp, x11_saved_display) != 0) { |
| error("x11_request_forwarding_with_spoofing: different " |
| "$DISPLAY already forwarded"); |
| return; |
| } |
| |
| cp = strchr(disp, ':'); |
| if (cp) |
| cp = strchr(cp, '.'); |
| if (cp) |
| screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); |
| else |
| screen_number = 0; |
| |
| if (x11_saved_proto == NULL) { |
| /* Save protocol name. */ |
| x11_saved_proto = xstrdup(proto); |
| /* |
| * Extract real authentication data and generate fake data |
| * of the same length. |
| */ |
| x11_saved_data = xmalloc(data_len); |
| x11_fake_data = xmalloc(data_len); |
| for (i = 0; i < data_len; i++) { |
| if (sscanf(data + 2 * i, "%2x", &value) != 1) |
| fatal("x11_request_forwarding: bad " |
| "authentication data: %.100s", data); |
| if (i % 4 == 0) |
| rnd = arc4random(); |
| x11_saved_data[i] = value; |
| x11_fake_data[i] = rnd & 0xff; |
| rnd >>= 8; |
| } |
| x11_saved_data_len = data_len; |
| x11_fake_data_len = data_len; |
| } |
| |
| /* Convert the fake data into hex. */ |
| new_data = tohex(x11_fake_data, data_len); |
| |
| /* Send the request packet. */ |
| if (compat20) { |
| channel_request_start(client_session_id, "x11-req", 0); |
| packet_put_char(0); /* XXX bool single connection */ |
| } else { |
| packet_start(SSH_CMSG_X11_REQUEST_FORWARDING); |
| } |
| packet_put_cstring(proto); |
| packet_put_cstring(new_data); |
| packet_put_int(screen_number); |
| packet_send(); |
| packet_write_wait(); |
| xfree(new_data); |
| } |
| |
| |
| /* -- agent forwarding */ |
| |
| /* Sends a message to the server to request authentication fd forwarding. */ |
| |
| void |
| auth_request_forwarding(void) |
| { |
| packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); |
| packet_send(); |
| packet_write_wait(); |
| } |