X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/80faa19fee1edc3f94ca9afd774d38a897ec2157..e4f7282d79462c20b197e1ce259c84c6297b5cb3:/channels.c diff --git a/channels.c b/channels.c index c4139454..11061389 100644 --- a/channels.c +++ b/channels.c @@ -1,78 +1,84 @@ /* - * - * channels.c - * * Author: Tatu Ylonen - * * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved - * - * Created: Fri Mar 24 16:35:24 1995 ylo - * * 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 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" -RCSID("$Id$"); +RCSID("$OpenBSD: channels.c,v 1.122 2001/06/03 14:55:38 markus Exp $"); #include "ssh.h" +#include "ssh1.h" +#include "ssh2.h" #include "packet.h" #include "xmalloc.h" -#include "buffer.h" -#include "authfd.h" #include "uidswap.h" -#include "readconf.h" -#include "servconf.h" - +#include "log.h" +#include "misc.h" #include "channels.h" -#include "nchan.h" #include "compat.h" +#include "canohost.h" +#include "key.h" +#include "authfd.h" -/* Maximum number of fake X11 displays to try. */ -#define MAX_DISPLAYS 1000 -/* Max len of agent socket */ -#define MAX_SOCKET_NAME 100 +/* -- channel core */ /* * Pointer to an array containing all allocated channels. The array is * dynamically extended as needed. */ -static Channel *channels = NULL; +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 are marked with type - * SSH_CHANNEL_FREE. + * initialized (at least the type field); unused slots set to NULL */ static int channels_alloc = 0; /* * Maximum file descriptor value used in any of the channels. This is - * updated in channel_allocate. + * updated in channel_new. */ -static int channel_max_fd_value = 0; - -/* Name and directory of socket for authentication agent forwarding. */ -static char *channel_forwarded_auth_socket_name = NULL; -static char *channel_forwarded_auth_socket_dir = NULL; - -/* Saved X11 authentication protocol name. */ -char *x11_saved_proto = NULL; +static int channel_max_fd = 0; -/* Saved X11 authentication data. This is the real data. */ -char *x11_saved_data = NULL; -unsigned 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. - */ -char *x11_fake_data = NULL; -unsigned int x11_fake_data_len; +/* -- tcp forwarding */ /* * Data structure for storing which hosts are permitted for forward requests. @@ -81,12 +87,14 @@ unsigned int x11_fake_data_len; * network (which might be behind a firewall). */ typedef struct { - char *host; /* Host name. */ - u_short port; /* Port number. */ + 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. */ static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION]; + /* Number of permitted host/port pairs in the array. */ static int num_permitted_opens = 0; /* @@ -96,27 +104,104 @@ static int num_permitted_opens = 0; */ static int all_opens_permitted = 0; -/* This is set to true if both sides support SSH_PROTOFLAG_HOST_IN_FWD_OPEN. */ -static int have_hostname_in_open = 0; -/* Sets specific protocol options. */ +/* -- X11 forwarding */ + +/* Maximum number of fake X11 displays to try. */ +#define MAX_DISPLAYS 1000 + +/* 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 char *x11_fake_data = NULL; +static u_int x11_fake_data_len; + + +/* -- agent forwarding */ + +#define NUM_SOCKS 10 + +/* Name and directory of socket for authentication agent forwarding. */ +static char *auth_sock_name = NULL; +static char *auth_sock_dir = NULL; + + +/* AF_UNSPEC or AF_INET or AF_INET6 */ +extern int IPv4or6; + +/* helper */ +void port_open_helper(Channel *c, char *rtype); -void -channel_set_options(int hostname_in_open) +/* -- channel core */ + +Channel * +channel_lookup(int id) { - have_hostname_in_open = hostname_in_open; + Channel *c; + + if (id < 0 || id > channels_alloc) { + log("channel_lookup: %d: bad id", id); + return NULL; + } + c = channels[id]; + if (c == NULL) { + log("channel_lookup: %d: bad id: channel free", id); + return NULL; + } + return c; } /* - * Permits opening to any host/port in SSH_MSG_PORT_OPEN. 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. + * Register filedescriptors for a channel, used when allocating a channel or + * when the channel consumer/producer is ready, e.g. shell exec'd */ -void -channel_permit_all_opens() +void +channel_register_fds(Channel *c, int rfd, int wfd, int efd, + int extusage, int nonblock) { - all_opens_permitted = 1; + /* 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->efd = efd; + c->extended_usage = extusage; + + /* XXX ugly hack: nonblock is only set by the server */ + if (nonblock && isatty(c->rfd)) { + debug("channel %d: rfd %d isatty", c->self, c->rfd); + c->isatty = 1; + if (!isatty(c->wfd)) { + error("channel %d: wfd %d is not a tty?", + c->self, c->wfd); + } + } else { + c->isatty = 0; + } + + /* enable nonblocking mode */ + if (nonblock) { + if (rfd != -1) + set_nonblock(rfd); + if (wfd != -1) + set_nonblock(wfd); + if (efd != -1) + set_nonblock(efd); + } } /* @@ -124,23 +209,20 @@ channel_permit_all_opens() * remote_name to be freed. */ -int -channel_allocate(int type, int sock, char *remote_name) +Channel * +channel_new(char *ctype, int type, int rfd, int wfd, int efd, + int window, int maxpack, int extusage, char *remote_name, int nonblock) { int i, found; Channel *c; - /* Update the maximum file descriptor value. */ - if (sock > channel_max_fd_value) - channel_max_fd_value = sock; - /* XXX set close-on-exec -markus */ - /* Do initial allocation if this is the first call. */ if (channels_alloc == 0) { + chan_init(); channels_alloc = 10; - channels = xmalloc(channels_alloc * sizeof(Channel)); + channels = xmalloc(channels_alloc * sizeof(Channel *)); for (i = 0; i < channels_alloc; i++) - channels[i].type = SSH_CHANNEL_FREE; + channels[i] = NULL; /* * Kludge: arrange a call to channel_stop_listening if we * terminate with fatal(). @@ -149,7 +231,7 @@ channel_allocate(int type, int sock, char *remote_name) } /* Try to find a free slot where to put the new channel. */ for (found = -1, i = 0; i < channels_alloc; i++) - if (channels[i].type == SSH_CHANNEL_FREE) { + if (channels[i] == NULL) { /* Found a free slot. */ found = i; break; @@ -158,511 +240,1541 @@ channel_allocate(int type, int sock, char *remote_name) /* There are no free slots. Take last+1 slot and expand the array. */ found = channels_alloc; channels_alloc += 10; - debug("channel: expanding %d", channels_alloc); - channels = xrealloc(channels, channels_alloc * sizeof(Channel)); + debug2("channel: expanding %d", channels_alloc); + channels = xrealloc(channels, channels_alloc * sizeof(Channel *)); for (i = found; i < channels_alloc; i++) - channels[i].type = SSH_CHANNEL_FREE; + channels[i] = NULL; } - /* Initialize and return new channel number. */ - c = &channels[found]; + /* Initialize and return new channel. */ + c = channels[found] = xmalloc(sizeof(Channel)); buffer_init(&c->input); buffer_init(&c->output); + buffer_init(&c->extended); chan_init_iostates(c); + channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); c->self = found; c->type = type; - c->sock = sock; + 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 = remote_name; + c->remote_window = 0; + c->remote_maxpacket = 0; + c->cb_fn = NULL; + c->cb_arg = NULL; + c->cb_event = 0; + c->dettach_user = NULL; + c->input_filter = NULL; debug("channel %d: new [%s]", found, remote_name); - return found; + return c; } -/* Free the channel and close its socket. */ +/* Close all channel fd/socket. */ -void -channel_free(int channel) +void +channel_close_fds(Channel *c) { - if (channel < 0 || channel >= channels_alloc || - channels[channel].type == SSH_CHANNEL_FREE) - packet_disconnect("channel free: bad local channel %d", channel); + debug3("channel_close_fds: channel %d: r %d w %d e %d", + c->self, c->rfd, c->wfd, c->efd); - if (compat13) - shutdown(channels[channel].sock, SHUT_RDWR); - close(channels[channel].sock); - buffer_free(&channels[channel].input); - buffer_free(&channels[channel].output); - channels[channel].type = SSH_CHANNEL_FREE; - if (channels[channel].remote_name) { - xfree(channels[channel].remote_name); - channels[channel].remote_name = NULL; + if (c->sock != -1) { + close(c->sock); + c->sock = -1; + } + if (c->rfd != -1) { + close(c->rfd); + c->rfd = -1; + } + if (c->wfd != -1) { + close(c->wfd); + c->wfd = -1; + } + if (c->efd != -1) { + close(c->efd); + c->efd = -1; + } +} + +/* Free the channel and close its fd/socket. */ + +void +channel_free(Channel *c) +{ + char *s; + int i, n; + + for (n = 0, i = 0; i < channels_alloc; i++) + if (channels[i]) + n++; + debug("channel_free: channel %d: %s, nchannels %d", c->self, + c->remote_name ? c->remote_name : "???", n); + + s = channel_open_message(); + debug3("channel_free: status: %s", s); + xfree(s); + + if (c->dettach_user != NULL) { + debug("channel_free: channel %d: dettaching channel user", c->self); + c->dettach_user(c->self, NULL); } + if (c->sock != -1) + shutdown(c->sock, SHUT_RDWR); + channel_close_fds(c); + buffer_free(&c->input); + buffer_free(&c->output); + buffer_free(&c->extended); + if (c->remote_name) { + xfree(c->remote_name); + c->remote_name = NULL; + } + channels[c->self] = NULL; + xfree(c); } + /* - * This is called just before select() to add any bits relevant to channels - * in the select bitmasks. + * Stops listening for channels, and removes any unix domain sockets that we + * might have. */ -void -channel_prepare_select(fd_set * readset, fd_set * writeset) +void +channel_stop_listening() { int i; - Channel *ch; - unsigned char *ucp; - unsigned int proto_len, data_len; + Channel *c; for (i = 0; i < channels_alloc; i++) { - ch = &channels[i]; -redo: - switch (ch->type) { - case SSH_CHANNEL_X11_LISTENER: - case SSH_CHANNEL_PORT_LISTENER: - case SSH_CHANNEL_AUTH_SOCKET: - FD_SET(ch->sock, readset); - break; - - case SSH_CHANNEL_OPEN: - if (compat13) { - if (buffer_len(&ch->input) < packet_get_maxsize()) - FD_SET(ch->sock, readset); - if (buffer_len(&ch->output) > 0) - FD_SET(ch->sock, writeset); + c = channels[i]; + if (c != NULL) { + switch (c->type) { + case SSH_CHANNEL_AUTH_SOCKET: + close(c->sock); + unlink(c->path); + channel_free(c); break; - } - /* test whether sockets are 'alive' for read/write */ - if (ch->istate == CHAN_INPUT_OPEN) - if (buffer_len(&ch->input) < packet_get_maxsize()) - FD_SET(ch->sock, readset); - if (ch->ostate == CHAN_OUTPUT_OPEN || - ch->ostate == CHAN_OUTPUT_WAIT_DRAIN) { - if (buffer_len(&ch->output) > 0) { - FD_SET(ch->sock, writeset); - } else if (ch->ostate == CHAN_OUTPUT_WAIT_DRAIN) { - chan_obuf_empty(ch); - } - } - break; - - case SSH_CHANNEL_INPUT_DRAINING: - if (!compat13) - fatal("cannot happen: IN_DRAIN"); - if (buffer_len(&ch->input) == 0) { - packet_start(SSH_MSG_CHANNEL_CLOSE); - packet_put_int(ch->remote_id); - packet_send(); - ch->type = SSH_CHANNEL_CLOSED; - debug("Closing channel %d after input drain.", ch->self); + case SSH_CHANNEL_PORT_LISTENER: + case SSH_CHANNEL_RPORT_LISTENER: + case SSH_CHANNEL_X11_LISTENER: + close(c->sock); + channel_free(c); break; - } - break; - - case SSH_CHANNEL_OUTPUT_DRAINING: - if (!compat13) - fatal("cannot happen: OUT_DRAIN"); - if (buffer_len(&ch->output) == 0) { - channel_free(i); + default: break; } - FD_SET(ch->sock, writeset); - break; + } + } +} - case SSH_CHANNEL_X11_OPEN: - /* - * 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. - */ - /* Check if the fixed size part of the packet is in buffer. */ - if (buffer_len(&ch->output) < 12) - break; +/* + * Closes the sockets/fds of all channels. This is used to close extra file + * descriptors after a fork. + */ - /* Parse the lengths of variable-length fields. */ - ucp = (unsigned char *) buffer_ptr(&ch->output); - 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 { - debug("Initial X11 packet contains bad byte order byte: 0x%x", - ucp[0]); - ch->type = SSH_CHANNEL_OPEN; - goto reject; - } +void +channel_close_all() +{ + int i; - /* Check if the whole packet is in buffer. */ - if (buffer_len(&ch->output) < - 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) - break; + for (i = 0; i < channels_alloc; i++) + if (channels[i] != NULL) + channel_close_fds(channels[i]); +} - /* Check if authentication protocol matches. */ - if (proto_len != strlen(x11_saved_proto) || - memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) { - debug("X11 connection uses different authentication protocol."); - ch->type = SSH_CHANNEL_OPEN; - goto reject; - } - /* 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) { - debug("X11 auth data does not match fake data."); - ch->type = SSH_CHANNEL_OPEN; - goto reject; - } - /* 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); - ch->type = SSH_CHANNEL_OPEN; - goto reject; - } - /* - * 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); +/* + * Returns true if no channel has too much buffered data, and false if one or + * more channel is overfull. + */ - /* Start normal processing for the channel. */ - ch->type = SSH_CHANNEL_OPEN; - goto redo; +int +channel_not_very_much_buffered_data() +{ + u_int i; + Channel *c; - reject: - /* - * We have received an X11 connection that has bad - * authentication information. - */ - log("X11 connection rejected because of wrong authentication.\r\n"); - buffer_clear(&ch->input); - buffer_clear(&ch->output); - if (compat13) { - close(ch->sock); - ch->sock = -1; - ch->type = SSH_CHANNEL_CLOSED; - packet_start(SSH_MSG_CHANNEL_CLOSE); - packet_put_int(ch->remote_id); - packet_send(); - } else { - debug("X11 rejected %d i%d/o%d", ch->self, ch->istate, ch->ostate); - chan_read_failed(ch); - chan_write_failed(ch); - debug("X11 rejected %d i%d/o%d", ch->self, ch->istate, ch->ostate); + for (i = 0; i < channels_alloc; i++) { + c = channels[i]; + if (c != NULL && c->type == SSH_CHANNEL_OPEN) { + if (!compat20 && buffer_len(&c->input) > packet_get_maxsize()) { + debug("channel %d: big input buffer %d", + c->self, buffer_len(&c->input)); + return 0; + } + if (buffer_len(&c->output) > packet_get_maxsize()) { + debug("channel %d: big output buffer %d", + c->self, buffer_len(&c->output)); + return 0; } - break; - - case SSH_CHANNEL_FREE: - default: - continue; } } + return 1; } -/* - * After select, perform any appropriate operations for channels which have - * events pending. - */ +/* Returns true if any channel is still open. */ -void -channel_after_select(fd_set * readset, fd_set * writeset) +int +channel_still_open() { - struct sockaddr addr; - int newsock, i, newch, len; - socklen_t addrlen; - Channel *ch; - char buf[16384], *remote_hostname; + int i; + Channel *c; - /* Loop over all channels... */ for (i = 0; i < channels_alloc; i++) { - ch = &channels[i]; - switch (ch->type) { + c = channels[i]; + if (c == NULL) + continue; + switch (c->type) { case SSH_CHANNEL_X11_LISTENER: - /* This is our fake X11 server socket. */ - if (FD_ISSET(ch->sock, readset)) { - debug("X11 connection requested."); - addrlen = sizeof(addr); - newsock = accept(ch->sock, &addr, &addrlen); - if (newsock < 0) { - error("accept: %.100s", strerror(errno)); - break; - } - remote_hostname = get_remote_hostname(newsock); - snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", - remote_hostname, get_peer_port(newsock)); - xfree(remote_hostname); - newch = channel_allocate(SSH_CHANNEL_OPENING, newsock, - xstrdup(buf)); - packet_start(SSH_SMSG_X11_OPEN); - packet_put_int(newch); - if (have_hostname_in_open) - packet_put_string(buf, strlen(buf)); - packet_send(); - } - break; - case SSH_CHANNEL_PORT_LISTENER: - /* - * This socket is listening for connections to a - * forwarded TCP/IP port. - */ - if (FD_ISSET(ch->sock, readset)) { - debug("Connection to port %d forwarding to %.100s port %d requested.", - ch->listening_port, ch->path, ch->host_port); - addrlen = sizeof(addr); - newsock = accept(ch->sock, &addr, &addrlen); - if (newsock < 0) { - error("accept: %.100s", strerror(errno)); - break; - } - remote_hostname = get_remote_hostname(newsock); - snprintf(buf, sizeof buf, "listen port %d for %.100s port %d, connect from %.200s port %d", - ch->listening_port, ch->path, ch->host_port, - remote_hostname, get_peer_port(newsock)); - xfree(remote_hostname); - newch = channel_allocate(SSH_CHANNEL_OPENING, newsock, - xstrdup(buf)); - packet_start(SSH_MSG_PORT_OPEN); - packet_put_int(newch); - packet_put_string(ch->path, strlen(ch->path)); - packet_put_int(ch->host_port); - if (have_hostname_in_open) - packet_put_string(buf, strlen(buf)); - packet_send(); - } - break; - + case SSH_CHANNEL_RPORT_LISTENER: + case SSH_CHANNEL_CLOSED: case SSH_CHANNEL_AUTH_SOCKET: - /* - * This is the authentication agent socket listening - * for connections from clients. - */ - if (FD_ISSET(ch->sock, readset)) { - addrlen = sizeof(addr); - newsock = accept(ch->sock, &addr, &addrlen); - if (newsock < 0) { - error("accept from auth socket: %.100s", strerror(errno)); - break; - } - newch = channel_allocate(SSH_CHANNEL_OPENING, newsock, - xstrdup("accepted auth socket")); - packet_start(SSH_SMSG_AGENT_OPEN); - packet_put_int(newch); - packet_send(); - } - break; - + case SSH_CHANNEL_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: - /* - * This is an open two-way communication channel. It - * is not of interest to us at this point what kind - * of data is being transmitted. - */ - - /* - * Read available incoming data and append it to - * buffer; shutdown socket, if read or write failes - */ - if (FD_ISSET(ch->sock, readset)) { - len = read(ch->sock, buf, sizeof(buf)); - if (len <= 0) { - if (compat13) { - buffer_consume(&ch->output, buffer_len(&ch->output)); - ch->type = SSH_CHANNEL_INPUT_DRAINING; - debug("Channel %d status set to input draining.", i); - } else { - chan_read_failed(ch); - } - break; - } - buffer_append(&ch->input, buf, len); - } - /* Send buffered output data to the socket. */ - if (FD_ISSET(ch->sock, writeset) && buffer_len(&ch->output) > 0) { - len = write(ch->sock, buffer_ptr(&ch->output), - buffer_len(&ch->output)); - if (len <= 0) { - if (compat13) { - buffer_consume(&ch->output, buffer_len(&ch->output)); - debug("Channel %d status set to input draining.", i); - ch->type = SSH_CHANNEL_INPUT_DRAINING; - } else { - chan_write_failed(ch); - } - break; - } - buffer_consume(&ch->output, len); - } - break; - + case SSH_CHANNEL_X11_OPEN: + return 1; + case SSH_CHANNEL_INPUT_DRAINING: case SSH_CHANNEL_OUTPUT_DRAINING: if (!compat13) fatal("cannot happen: OUT_DRAIN"); - /* Send buffered output data to the socket. */ - if (FD_ISSET(ch->sock, writeset) && buffer_len(&ch->output) > 0) { - len = write(ch->sock, buffer_ptr(&ch->output), - buffer_len(&ch->output)); - if (len <= 0) - buffer_consume(&ch->output, buffer_len(&ch->output)); - else - buffer_consume(&ch->output, len); - } - break; - - case SSH_CHANNEL_X11_OPEN: - case SSH_CHANNEL_FREE: + return 1; default: - continue; + fatal("channel_still_open: bad channel type %d", c->type); + /* NOTREACHED */ } } + return 0; } -/* If there is data to send to the connection, send some of it now. */ +/* Returns the id of an open channel suitable for keepaliving */ -void -channel_output_poll() +int +channel_find_open() { - int len, i; - Channel *ch; + int i; + Channel *c; for (i = 0; i < channels_alloc; i++) { - ch = &channels[i]; - - /* We are only interested in channels that can have buffered incoming data. */ - if (compat13) { - if (ch->type != SSH_CHANNEL_OPEN && - ch->type != SSH_CHANNEL_INPUT_DRAINING) - continue; - } else { - if (ch->type != SSH_CHANNEL_OPEN) - continue; - if (ch->istate != CHAN_INPUT_OPEN && - ch->istate != CHAN_INPUT_WAIT_DRAIN) - continue; - } - - /* Get the amount of buffered data for this channel. */ - len = buffer_len(&ch->input); - if (len > 0) { - /* Send some data for the other side over the secure connection. */ - if (packet_is_interactive()) { - if (len > 1024) - len = 512; - } else { - /* Keep the packets at reasonable size. */ - if (len > packet_get_maxsize()/2) - len = packet_get_maxsize()/2; - } - packet_start(SSH_MSG_CHANNEL_DATA); - packet_put_int(ch->remote_id); - packet_put_string(buffer_ptr(&ch->input), len); - packet_send(); - buffer_consume(&ch->input, len); - } else if (ch->istate == CHAN_INPUT_WAIT_DRAIN) { - if (compat13) - fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3"); - /* - * input-buffer is empty and read-socket shutdown: - * tell peer, that we will not send more data: send IEOF - */ - chan_ibuf_empty(ch); + c = channels[i]; + if (c == NULL) + 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; } + /* - * This is called when a packet of type CHANNEL_DATA has just been received. - * The message type has already been consumed, but channel number and data is - * still there. + * Returns a message describing the currently open forwarded connections, + * suitable for sending to the client. The message contains crlf pairs for + * newlines. */ -void -channel_input_data(int payload_len) +char * +channel_open_message() { - int id; - char *data; - unsigned int data_len; - Channel *ch; - - /* Get the channel number and verify it. */ - id = packet_get_int(); - if (id < 0 || id >= channels_alloc) - packet_disconnect("Received data for nonexistent channel %d.", id); - ch = &channels[id]; - - if (ch->type == SSH_CHANNEL_FREE) - packet_disconnect("Received data for free channel %d.", ch->self); - - /* Ignore any data for non-open channels (might happen on close) */ - if (ch->type != SSH_CHANNEL_OPEN && - ch->type != SSH_CHANNEL_X11_OPEN) - return; + Buffer buffer; + Channel *c; + char buf[1024], *cp; + int i; - /* same for protocol 1.5 if output end is no longer open */ - if (!compat13 && ch->ostate != CHAN_OUTPUT_OPEN) - return; + 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)\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); + 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; +} - /* Get the data. */ - data = packet_get_string(&data_len); - packet_integrity_check(payload_len, 4 + 4 + data_len, SSH_MSG_CHANNEL_DATA); - buffer_append(&ch->output, data, data_len); - xfree(data); +void +channel_send_open(int id) +{ + Channel *c = channel_lookup(id); + if (c == NULL) { + log("channel_send_open: %d: bad id", id); + return; + } + debug("send channel open %d", 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(int id, char *service, int wantconfirm) +{ + channel_request_start(id, service, wantconfirm); + packet_send(); + debug("channel request %d: %s", id, service) ; +} +void +channel_request_start(int id, char *service, int wantconfirm) +{ + Channel *c = channel_lookup(id); + if (c == NULL) { + log("channel_request: %d: bad id", id); + return; + } + packet_start(SSH2_MSG_CHANNEL_REQUEST); + packet_put_int(c->remote_id); + packet_put_cstring(service); + packet_put_char(wantconfirm); +} +void +channel_register_callback(int id, int mtype, channel_callback_fn *fn, void *arg) +{ + Channel *c = channel_lookup(id); + if (c == NULL) { + log("channel_register_callback: %d: bad id", id); + return; + } + c->cb_event = mtype; + c->cb_fn = fn; + c->cb_arg = arg; +} +void +channel_register_cleanup(int id, channel_callback_fn *fn) +{ + Channel *c = channel_lookup(id); + if (c == NULL) { + log("channel_register_cleanup: %d: bad id", id); + return; + } + c->dettach_user = fn; +} +void +channel_cancel_cleanup(int id) +{ + Channel *c = channel_lookup(id); + if (c == NULL) { + log("channel_cancel_cleanup: %d: bad id", id); + return; + } + c->dettach_user = NULL; +} +void +channel_register_filter(int id, channel_filter_fn *fn) +{ + Channel *c = channel_lookup(id); + if (c == NULL) { + log("channel_register_filter: %d: bad id", id); + return; + } + c->input_filter = fn; +} + +void +channel_set_fds(int id, int rfd, int wfd, int efd, + int extusage, int nonblock) +{ + 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); + c->type = SSH_CHANNEL_OPEN; + /* XXX window size? */ + c->local_window = c->local_window_max = c->local_maxpacket * 2; + packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); + packet_put_int(c->remote_id); + packet_put_int(c->local_window); + packet_send(); } /* - * Returns true if no channel has too much buffered data, and false if one or - * more channel is overfull. + * '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]; -int -channel_not_very_much_buffered_data() +void +channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset) +{ + FD_SET(c->sock, readset); +} + +void +channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset) { - unsigned int i; - Channel *ch; + debug3("channel %d: waiting for connection", c->self); + FD_SET(c->sock, writeset); +} - for (i = 0; i < channels_alloc; i++) { - ch = &channels[i]; - if (ch->type == SSH_CHANNEL_OPEN) { - if (buffer_len(&ch->input) > packet_get_maxsize()) - return 0; - if (buffer_len(&ch->output) > packet_get_maxsize()) - return 0; +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); +} + +void +channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset) +{ + /* test whether sockets are 'alive' for read/write */ + if (c->istate == CHAN_INPUT_OPEN) + if (buffer_len(&c->input) < packet_get_maxsize()) + FD_SET(c->sock, readset); + if (c->ostate == CHAN_OUTPUT_OPEN || + c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { + if (buffer_len(&c->output) > 0) { + FD_SET(c->sock, writeset); + } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { + chan_obuf_empty(c); + } + } +} + +void +channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset) +{ + if (c->istate == CHAN_INPUT_OPEN && + c->remote_window > 0 && + buffer_len(&c->input) < c->remote_window) + 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) { + chan_obuf_empty(c); + } + } + /** XXX check close conditions, too */ + if (c->efd != -1) { + if (c->extended_usage == CHAN_EXTENDED_WRITE && + buffer_len(&c->extended) > 0) + FD_SET(c->efd, writeset); + else if (c->extended_usage == CHAN_EXTENDED_READ && + buffer_len(&c->extended) < c->remote_window) + FD_SET(c->efd, readset); + } +} + +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; + debug("channel %d: closing after input drain.", c->self); + } +} + +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 + */ +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 = (u_char *) 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 { + debug("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) { + debug("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) { + debug("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; +} + +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. + */ + log("X11 connection rejected because of wrong authentication."); + buffer_clear(&c->input); + buffer_clear(&c->output); + close(c->sock); + c->sock = -1; + c->type = SSH_CHANNEL_CLOSED; + packet_start(SSH_MSG_CHANNEL_CLOSE); + packet_put_int(c->remote_id); + packet_send(); + } +} + +void +channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset) +{ + int ret = x11_open_helper(&c->output); + if (ret == 1) { + c->type = SSH_CHANNEL_OPEN; + if (compat20) + channel_pre_open_20(c, readset, writeset); + else + channel_pre_open_15(c, readset, writeset); + } else if (ret == -1) { + debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate); + chan_read_failed(c); /** force close? */ + chan_write_failed(c); + debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); + } +} + +/* try to decode a socks4 header */ +int +channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset) +{ + u_char *p, *host; + 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); + + debug("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, (char *)&s4_rsp, sizeof(s4_rsp)); + return 1; +} + +/* dynamic port forwarding */ +void +channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset) +{ + u_char *p; + int have, ret; + + have = buffer_len(&c->input); + + debug2("channel %d: pre_dynamic: have %d", c->self, have); + /* buffer_dump(&c->input); */ + /* check if the fixed size part of the packet is in buffer. */ + if (have < 4) { + /* 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; + 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. */ +void +channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset) +{ + Channel *nc; + struct sockaddr 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, &addr, &addrlen); + if (newsock < 0) { + error("accept: %.100s", strerror(errno)); + return; + } + 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, xstrdup(buf), 1); + if (nc == NULL) { + close(newsock); + xfree(remote_ipaddr); + return; + } + if (compat20) { + packet_start(SSH2_MSG_CHANNEL_OPEN); + packet_put_cstring("x11"); + packet_put_int(nc->self); + packet_put_int(c->local_window_max); + packet_put_int(c->local_maxpacket); + /* originator ipaddr and port */ + packet_put_cstring(remote_ipaddr); + if (datafellows & SSH_BUG_X11FWD) { + debug("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_string(buf, strlen(buf)); + packet_send(); + } + xfree(remote_ipaddr); + } +} + +void +port_open_helper(Channel *c, char *rtype) +{ + int direct; + char buf[1024]; + char *remote_ipaddr = get_peer_ipaddr(c->sock); + u_short 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(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); +} + +/* + * This socket is listening for connections to a forwarded TCP/IP port. + */ +void +channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset) +{ + Channel *nc; + struct sockaddr 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); + + rtype = (c->type == SSH_CHANNEL_RPORT_LISTENER) ? + "forwarded-tcpip" : "direct-tcpip"; + nextstate = (c->host_port == 0 && + c->type != SSH_CHANNEL_RPORT_LISTENER) ? + SSH_CHANNEL_DYNAMIC : SSH_CHANNEL_OPENING; + + addrlen = sizeof(addr); + newsock = accept(c->sock, &addr, &addrlen); + if (newsock < 0) { + error("accept: %.100s", strerror(errno)); + return; + } + nc = channel_new(rtype, + nextstate, newsock, newsock, -1, + c->local_window_max, c->local_maxpacket, + 0, xstrdup(rtype), 1); + if (nc == NULL) { + error("channel_post_port_listener: no new channel:"); + close(newsock); + return; + } + 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) + port_open_helper(nc, rtype); + } +} + +/* + * This is the authentication agent socket listening for connections from + * clients. + */ +void +channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset) +{ + Channel *nc; + char *name; + int newsock; + struct sockaddr addr; + socklen_t addrlen; + + if (FD_ISSET(c->sock, readset)) { + addrlen = sizeof(addr); + newsock = accept(c->sock, &addr, &addrlen); + if (newsock < 0) { + error("accept from auth socket: %.100s", strerror(errno)); + return; + } + name = xstrdup("accepted auth socket"); + nc = channel_new("accepted auth socket", + SSH_CHANNEL_OPENING, newsock, newsock, -1, + c->local_window_max, c->local_maxpacket, + 0, name, 1); + if (nc == NULL) { + error("channel_post_auth_listener: channel_new failed"); + xfree(name); + close(newsock); + } + 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(); + } +} + +void +channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset) +{ + int err = 0; + int sz = sizeof(err); + + if (FD_ISSET(c->sock, writeset)) { + if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err, + &sz) < 0) { + err = errno; + error("getsockopt SO_ERROR failed"); + } + if (err == 0) { + debug("channel %d: connected", c->self); + 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: not connected: %s", + c->self, strerror(err)); + 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(); + } +} + +int +channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset) +{ + char buf[16*1024]; + int len; + + if (c->rfd != -1 && + FD_ISSET(c->rfd, readset)) { + len = read(c->rfd, buf, sizeof(buf)); + if (len < 0 && (errno == EINTR || errno == EAGAIN)) + return 1; + if (len <= 0) { + debug("channel %d: read<=0 rfd %d len %d", + c->self, c->rfd, len); + if (c->type != SSH_CHANNEL_OPEN) { + debug("channel %d: not open", c->self); + chan_mark_dead(c); + return -1; + } else if (compat13) { + buffer_consume(&c->output, buffer_len(&c->output)); + c->type = SSH_CHANNEL_INPUT_DRAINING; + debug("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) { + debug("channel %d: filter stops", c->self); + chan_read_failed(c); + } + } else { + buffer_append(&c->input, buf, len); + } + } + return 1; +} +int +channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset) +{ + struct termios tio; + int len; + + /* Send buffered output data to the socket. */ + if (c->wfd != -1 && + FD_ISSET(c->wfd, writeset) && + buffer_len(&c->output) > 0) { + len = write(c->wfd, buffer_ptr(&c->output), + buffer_len(&c->output)); + if (len < 0 && (errno == EINTR || errno == EAGAIN)) + return 1; + if (len <= 0) { + if (c->type != SSH_CHANNEL_OPEN) { + debug("channel %d: not open", c->self); + chan_mark_dead(c); + return -1; + } else if (compat13) { + buffer_consume(&c->output, buffer_len(&c->output)); + debug("channel %d: input draining.", c->self); + c->type = SSH_CHANNEL_INPUT_DRAINING; + } else { + chan_write_failed(c); + } + return -1; + } + if (compat20 && c->isatty) { + 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 + data) + */ + packet_send_ignore(4 + len); + packet_send(); + } + } + buffer_consume(&c->output, len); + if (compat20 && len > 0) { + c->local_consumed += len; + } + } + return 1; +} +int +channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset) +{ + char buf[16*1024]; + int len; + +/** XXX handle drain efd, too */ + if (c->efd != -1) { + if (c->extended_usage == CHAN_EXTENDED_WRITE && + FD_ISSET(c->efd, writeset) && + buffer_len(&c->extended) > 0) { + len = write(c->efd, buffer_ptr(&c->extended), + buffer_len(&c->extended)); + debug2("channel %d: written %d to efd %d", + c->self, len, c->efd); + if (len < 0 && (errno == EINTR || errno == EAGAIN)) + return 1; + if (len <= 0) { + debug2("channel %d: closing write-efd %d", + c->self, c->efd); + close(c->efd); + c->efd = -1; + } else { + buffer_consume(&c->extended, len); + c->local_consumed += len; + } + } else if (c->extended_usage == CHAN_EXTENDED_READ && + FD_ISSET(c->efd, readset)) { + len = read(c->efd, buf, sizeof(buf)); + debug2("channel %d: read %d from efd %d", + c->self, len, c->efd); + if (len < 0 && (errno == EINTR || errno == EAGAIN)) + return 1; + if (len <= 0) { + debug2("channel %d: closing read-efd %d", + c->self, c->efd); + close(c->efd); + c->efd = -1; + } else { + buffer_append(&c->extended, buf, len); + } } } return 1; } +int +channel_check_window(Channel *c) +{ + if (c->type == SSH_CHANNEL_OPEN && + !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && + 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; +} + +void +channel_post_open_1(Channel *c, fd_set * readset, fd_set * writeset) +{ + channel_handle_rfd(c, readset, writeset); + channel_handle_wfd(c, readset, writeset); +} -/* This is called after receiving CHANNEL_CLOSE/IEOF. */ +void +channel_post_open_2(Channel *c, fd_set * readset, fd_set * writeset) +{ + channel_handle_rfd(c, readset, writeset); + channel_handle_wfd(c, readset, writeset); + channel_handle_efd(c, readset, writeset); -void -channel_input_close() + channel_check_window(c); +} + +void +channel_post_output_drain_13(Channel *c, fd_set * readset, fd_set * writeset) { - int channel; + 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_consume(&c->output, buffer_len(&c->output)); + else + buffer_consume(&c->output, len); + } +} + +void +channel_handler_init_20(void) +{ + channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20; + 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_2; + 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_2; +} + +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_1; + 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_1; +} + +void +channel_handler_init_15(void) +{ + channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_15; + 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_1; + channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; + channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1; +} + +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(); +} + +void +channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset) +{ + static int did_init = 0; + 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); + if (chan_is_dead(c)) { + /* + * we have to remove the fd's from the select mask + * before the channels are free'd and the fd's are + * closed + */ + if (c->wfd != -1) + FD_CLR(c->wfd, writeset); + if (c->rfd != -1) + FD_CLR(c->rfd, readset); + if (c->efd != -1) { + if (c->extended_usage == CHAN_EXTENDED_READ) + FD_CLR(c->efd, readset); + if (c->extended_usage == CHAN_EXTENDED_WRITE) + FD_CLR(c->efd, writeset); + } + channel_free(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, + int rekeying) +{ + int n; + u_int sz; + + n = MAX(*maxfdp, channel_max_fd); + + sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); + if (*readsetp == NULL || n > *maxfdp) { + if (*readsetp) + xfree(*readsetp); + if (*writesetp) + xfree(*writesetp); + *readsetp = xmalloc(sz); + *writesetp = xmalloc(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() +{ + int len, i; + Channel *c; + + 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? */ + debug2("channel %d: no 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) { + /* + * 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 + */ + chan_ibuf_empty(c); + } + /* Send extended data, i.e. stderr */ + if (compat20 && + c->remote_window > 0 && + (len = buffer_len(&c->extended)) > 0 && + c->extended_usage == CHAN_EXTENDED_READ) { + debug2("channel %d: rwin %d elen %d 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 */ + +void +channel_input_data(int type, int plen, 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; + + /* same for protocol 1.5 if output end is no longer open */ + if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) + return; + + /* Get the data. */ + data = packet_get_string(&data_len); + packet_done(); + + if (compat20){ + if (data_len > c->local_maxpacket) { + log("channel %d: rcvd big packet %d, maxpack %d", + c->self, data_len, c->local_maxpacket); + } + if (data_len > c->local_window) { + log("channel %d: rcvd too much data %d, win %d", + c->self, data_len, c->local_window); + xfree(data); + return; + } + c->local_window -= data_len; + }else{ + packet_integrity_check(plen, 4 + 4 + data_len, type); + } + buffer_append(&c->output, data, data_len); + xfree(data); +} + +void +channel_input_extended_data(int type, int plen, void *ctxt) +{ + int id; + int tcode; + char *data; + u_int data_len; + Channel *c; /* Get the channel number and verify it. */ - channel = packet_get_int(); - if (channel < 0 || channel >= channels_alloc || - channels[channel].type == SSH_CHANNEL_FREE) - packet_disconnect("Received data for nonexistent channel %d.", channel); - - if (!compat13) { - /* proto version 1.5 overloads CLOSE with IEOF */ - chan_rcvd_ieof(&channels[channel]); + 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) { + log("channel %d: ext data for non open", id); + return; + } + tcode = packet_get_int(); + if (c->efd == -1 || + c->extended_usage != CHAN_EXTENDED_WRITE || + tcode != SSH2_EXTENDED_DATA_STDERR) { + log("channel %d: bad ext data", c->self); + return; + } + data = packet_get_string(&data_len); + packet_done(); + if (data_len > c->local_window) { + log("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); +} + +void +channel_input_ieof(int type, int plen, void *ctxt) +{ + int id; + Channel *c; + + packet_integrity_check(plen, 4, type); + + id = packet_get_int(); + c = channel_lookup(id); + if (c == NULL) + packet_disconnect("Received ieof for nonexistent channel %d.", id); + chan_rcvd_ieof(c); +} + +void +channel_input_close(int type, int plen, void *ctxt) +{ + int id; + Channel *c; + + packet_integrity_check(plen, 4, type); + + id = packet_get_int(); + 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(channels[channel].remote_id); + packet_put_int(c->remote_id); packet_send(); /* @@ -672,228 +1784,265 @@ channel_input_close() * no-one to receive the confirmation. The channel gets freed when * the confirmation arrives. */ - if (channels[channel].type != SSH_CHANNEL_CLOSED) { + if (c->type != SSH_CHANNEL_CLOSED) { /* * Not a closed channel - mark it as draining, which will * cause it to be freed later. */ - buffer_consume(&channels[channel].input, - buffer_len(&channels[channel].input)); - channels[channel].type = SSH_CHANNEL_OUTPUT_DRAINING; + buffer_consume(&c->input, buffer_len(&c->input)); + c->type = SSH_CHANNEL_OUTPUT_DRAINING; } } -/* This is called after receiving CHANNEL_CLOSE_CONFIRMATION/OCLOSE. */ - -void -channel_input_close_confirmation() +/* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ +void +channel_input_oclose(int type, int plen, void *ctxt) { - int channel; - - /* Get the channel number and verify it. */ - channel = packet_get_int(); - if (channel < 0 || channel >= channels_alloc) - packet_disconnect("Received close confirmation for out-of-range channel %d.", - channel); - - if (!compat13) { - /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ - chan_rcvd_oclose(&channels[channel]); - return; - } - if (channels[channel].type != SSH_CHANNEL_CLOSED) - packet_disconnect("Received close confirmation for non-closed channel %d (type %d).", - channel, channels[channel].type); - - /* Free the channel. */ - channel_free(channel); + int id = packet_get_int(); + Channel *c = channel_lookup(id); + packet_integrity_check(plen, 4, type); + if (c == NULL) + packet_disconnect("Received oclose for nonexistent channel %d.", id); + chan_rcvd_oclose(c); } -/* This is called after receiving CHANNEL_OPEN_CONFIRMATION. */ +void +channel_input_close_confirmation(int type, int plen, void *ctxt) +{ + int id = packet_get_int(); + Channel *c = channel_lookup(id); + + packet_done(); + 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); +} -void -channel_input_open_confirmation() +void +channel_input_open_confirmation(int type, int plen, void *ctxt) { - int channel, remote_channel; + int id, remote_id; + Channel *c; - /* Get the channel number and verify it. */ - channel = packet_get_int(); - if (channel < 0 || channel >= channels_alloc || - channels[channel].type != SSH_CHANNEL_OPENING) - packet_disconnect("Received open confirmation for non-opening channel %d.", - channel); + if (!compat20) + packet_integrity_check(plen, 4 + 4, type); - /* Get remote side's id for this channel. */ - remote_channel = packet_get_int(); + 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. */ - channels[channel].remote_id = remote_channel; - channels[channel].type = SSH_CHANNEL_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(); + packet_done(); + if (c->cb_fn != NULL && c->cb_event == type) { + debug2("callback start"); + c->cb_fn(c->self, c->cb_arg); + debug2("callback done"); + } + debug("channel %d: open confirm rwindow %d rmax %d", c->self, + c->remote_window, c->remote_maxpacket); + } } -/* This is called after receiving CHANNEL_OPEN_FAILURE from the other side. */ +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"; +} -void -channel_input_open_failure() +void +channel_input_open_failure(int type, int plen, void *ctxt) { - int channel; + int id, reason; + char *msg = NULL, *lang = NULL; + Channel *c; - /* Get the channel number and verify it. */ - channel = packet_get_int(); - if (channel < 0 || channel >= channels_alloc || - channels[channel].type != SSH_CHANNEL_OPENING) - packet_disconnect("Received open failure for non-opening channel %d.", - channel); + if (!compat20) + packet_integrity_check(plen, 4, type); + 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); + } + packet_done(); + log("channel %d: open failed: %s%s%s", id, + reason2txt(reason), msg ? ": ": "", msg ? msg : ""); + if (msg != NULL) + xfree(msg); + if (lang != NULL) + xfree(lang); + } /* Free the channel. This will also close the socket. */ - channel_free(channel); + channel_free(c); } -/* - * Stops listening for channels, and removes any unix domain sockets that we - * might have. - */ - -void -channel_stop_listening() +void +channel_input_channel_request(int type, int plen, void *ctxt) { - int i; - for (i = 0; i < channels_alloc; i++) { - switch (channels[i].type) { - case SSH_CHANNEL_AUTH_SOCKET: - close(channels[i].sock); - remove(channels[i].path); - channel_free(i); - break; - case SSH_CHANNEL_PORT_LISTENER: - case SSH_CHANNEL_X11_LISTENER: - close(channels[i].sock); - channel_free(i); - break; - default: - break; - } + int id; + Channel *c; + + id = packet_get_int(); + c = channel_lookup(id); + + if (c == NULL || + (c->type != SSH_CHANNEL_OPEN && c->type != SSH_CHANNEL_LARVAL)) + packet_disconnect("Received request for " + "non-open channel %d.", id); + if (c->cb_fn != NULL && c->cb_event == type) { + debug2("callback start"); + c->cb_fn(c->self, c->cb_arg); + debug2("callback done"); + } else { + char *service = packet_get_string(NULL); + debug("channel %d: rcvd request for %s", c->self, service); + debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event); + xfree(service); } } -/* - * Closes the sockets of all channels. This is used to close extra file - * descriptors after a fork. - */ - -void -channel_close_all() +void +channel_input_window_adjust(int type, int plen, void *ctxt) { - int i; - for (i = 0; i < channels_alloc; i++) { - if (channels[i].type != SSH_CHANNEL_FREE) - close(channels[i].sock); + Channel *c; + int id, adjust; + + if (!compat20) + return; + + /* Get the channel number and verify it. */ + id = packet_get_int(); + c = channel_lookup(id); + + if (c == NULL || c->type != SSH_CHANNEL_OPEN) { + log("Received window adjust for " + "non-open channel %d.", id); + return; } + adjust = packet_get_int(); + packet_done(); + debug2("channel %d: rcvd adjust %d", id, adjust); + c->remote_window += adjust; } -/* Returns the maximum file descriptor number used by the channels. */ - -int -channel_max_fd() +void +channel_input_port_open(int type, int plen, void *ctxt) { - return channel_max_fd_value; -} + Channel *c = NULL; + u_short host_port; + char *host, *originator_string; + int remote_id, sock = -1; -/* Returns true if any channel is still open. */ + remote_id = packet_get_int(); + host = packet_get_string(NULL); + host_port = packet_get_int(); -int -channel_still_open() -{ - unsigned int i; - for (i = 0; i < channels_alloc; i++) - switch (channels[i].type) { - case SSH_CHANNEL_FREE: - case SSH_CHANNEL_X11_LISTENER: - case SSH_CHANNEL_PORT_LISTENER: - case SSH_CHANNEL_CLOSED: - case SSH_CHANNEL_AUTH_SOCKET: - continue; - case SSH_CHANNEL_OPENING: - case SSH_CHANNEL_OPEN: - case SSH_CHANNEL_X11_OPEN: - return 1; - case SSH_CHANNEL_INPUT_DRAINING: - case SSH_CHANNEL_OUTPUT_DRAINING: - if (!compat13) - fatal("cannot happen: OUT_DRAIN"); - return 1; - default: - fatal("channel_still_open: bad channel type %d", channels[i].type); - /* NOTREACHED */ + 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_done(); + sock = channel_connect_to(host, host_port); + if (sock != -1) { + c = channel_new("connected socket", + SSH_CHANNEL_CONNECTING, sock, sock, -1, 0, 0, 0, + originator_string, 1); + if (c == NULL) { + error("channel_input_port_open: channel_new failed"); + close(sock); + } else { + c->remote_id = remote_id; } - return 0; + } + if (c == NULL) { + packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); + packet_put_int(remote_id); + packet_send(); + } + xfree(host); } -/* - * Returns a message describing the currently open forwarded connections, - * suitable for sending to the client. The message contains crlf pairs for - * newlines. - */ - -char * -channel_open_message() -{ - Buffer buffer; - int i; - char buf[512], *cp; - buffer_init(&buffer); - snprintf(buf, sizeof buf, "The following connections are open:\r\n"); - buffer_append(&buffer, buf, strlen(buf)); - for (i = 0; i < channels_alloc; i++) { - Channel *c = &channels[i]; - switch (c->type) { - case SSH_CHANNEL_FREE: - case SSH_CHANNEL_X11_LISTENER: - case SSH_CHANNEL_PORT_LISTENER: - case SSH_CHANNEL_CLOSED: - case SSH_CHANNEL_AUTH_SOCKET: - continue; - case SSH_CHANNEL_OPENING: - case SSH_CHANNEL_OPEN: - case SSH_CHANNEL_X11_OPEN: - case SSH_CHANNEL_INPUT_DRAINING: - case SSH_CHANNEL_OUTPUT_DRAINING: - snprintf(buf, sizeof buf, " #%d %.300s (t%d r%d i%d/%d o%d/%d)\r\n", - c->self, c->remote_name, - c->type, c->remote_id, - c->istate, buffer_len(&c->input), - c->ostate, buffer_len(&c->output)); - buffer_append(&buffer, buf, strlen(buf)); - continue; - default: - fatal("channel_still_open: bad channel type %d", c->type); - /* NOTREACHED */ - } - } - buffer_append(&buffer, "\0", 1); - cp = xstrdup(buffer_ptr(&buffer)); - buffer_free(&buffer); - return cp; -} +/* -- tcp forwarding */ /* * Initiate forwarding of connections to local port "port" through the secure * channel to host:port from remote side. */ +int +channel_request_local_forwarding(u_short listen_port, const char *host_to_connect, + u_short port_to_connect, int gateway_ports) +{ + return channel_request_forwarding( + NULL, listen_port, + host_to_connect, port_to_connect, + gateway_ports, /*remote_fwd*/ 0); +} -void -channel_request_local_forwarding(u_short port, const char *host, - u_short host_port, int gateway_ports) +/* + * If 'remote_fwd' is true we have a '-R style' listener for protocol 2 + * (SSH_CHANNEL_RPORT_LISTENER). + */ +int +channel_request_forwarding( + const char *listen_address, u_short listen_port, + const char *host_to_connect, u_short port_to_connect, + int gateway_ports, int remote_fwd) { - int success, ch, sock, on = 1; + Channel *c; + int success, sock, on = 1, type; struct addrinfo hints, *ai, *aitop; char ntop[NI_MAXHOST], strport[NI_MAXSERV]; + const char *host; struct linger linger; - if (strlen(host) > sizeof(channels[0].path) - 1) - packet_disconnect("Forward host name too long."); + success = 0; + + if (remote_fwd) { + host = listen_address; + type = SSH_CHANNEL_RPORT_LISTENER; + } else { + host = host_to_connect; + type = SSH_CHANNEL_PORT_LISTENER; + } + + if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) { + error("Forward host name too long."); + return success; + } + /* XXX listen_address is currently ignored */ /* * getaddrinfo returns a loopback address if the hostname is * set to NULL and hints.ai_flags is not AI_PASSIVE @@ -902,17 +2051,16 @@ channel_request_local_forwarding(u_short port, const char *host, hints.ai_family = IPv4or6; hints.ai_flags = gateway_ports ? AI_PASSIVE : 0; hints.ai_socktype = SOCK_STREAM; - snprintf(strport, sizeof strport, "%d", port); + snprintf(strport, sizeof strport, "%d", listen_port); if (getaddrinfo(NULL, strport, &hints, &aitop) != 0) packet_disconnect("getaddrinfo: fatal error"); - success = 0; for (ai = aitop; ai; ai = ai->ai_next) { if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) continue; if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { - error("channel_request_local_forwarding: getnameinfo failed"); + error("channel_request_forwarding: getnameinfo failed"); continue; } /* Create a port to listen for the host. */ @@ -939,7 +2087,7 @@ channel_request_local_forwarding(u_short port, const char *host, error("bind: %.100s", strerror(errno)); else verbose("bind: %.100s", strerror(errno)); - + close(sock); continue; } @@ -950,16 +2098,24 @@ channel_request_local_forwarding(u_short port, const char *host, continue; } /* Allocate a channel number for the socket. */ - ch = channel_allocate(SSH_CHANNEL_PORT_LISTENER, sock, - xstrdup("port listener")); - strlcpy(channels[ch].path, host, sizeof(channels[ch].path)); - channels[ch].host_port = host_port; - channels[ch].listening_port = port; + c = channel_new("port listener", type, sock, sock, -1, + CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, + 0, xstrdup("port listener"), 1); + if (c == NULL) { + error("channel_request_forwarding: channel_new failed"); + close(sock); + continue; + } + strlcpy(c->path, host, sizeof(c->path)); + c->host_port = port_to_connect; + c->listening_port = listen_port; success = 1; } if (success == 0) - packet_disconnect("cannot listen port: %d", port); + error("channel_request_forwarding: cannot listen to port: %d", + listen_port); freeaddrinfo(aitop); + return success; } /* @@ -967,32 +2123,57 @@ channel_request_local_forwarding(u_short port, const char *host, * the secure channel to host:port from local side. */ -void -channel_request_remote_forwarding(u_short port, const char *host, - u_short remote_port) +void +channel_request_remote_forwarding(u_short listen_port, + const char *host_to_connect, u_short port_to_connect) { - int payload_len; + int payload_len, 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"); - permitted_opens[num_permitted_opens].host = xstrdup(host); - permitted_opens[num_permitted_opens].port = remote_port; - num_permitted_opens++; - /* Send the forward request to the remote side. */ - packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); - packet_put_int(port); - packet_put_string(host, strlen(host)); - packet_put_int(remote_port); - packet_send(); - packet_write_wait(); + if (compat20) { + const char *address_to_bind = "0.0.0.0"; + packet_start(SSH2_MSG_GLOBAL_REQUEST); + packet_put_cstring("tcpip-forward"); + packet_put_char(0); /* 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. It will send a disconnect - * message on failure, and we will never see it here. - */ - packet_read_expect(&payload_len, SSH_SMSG_SUCCESS); + /* Wait for response from the remote side. */ + type = packet_read(&payload_len); + switch (type) { + case SSH_SMSG_SUCCESS: + success = 1; + break; + case SSH_SMSG_FAILURE: + log("Warning: Server denied remote port forwarding."); + 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++; + } } /* @@ -1001,8 +2182,8 @@ channel_request_remote_forwarding(u_short port, const char *host, * message if there was an error). This never returns if there was an error. */ -void -channel_input_port_forward_request(int is_root) +void +channel_input_port_forward_request(int is_root, int gateway_ports) { u_short port, host_port; char *hostname; @@ -1012,6 +2193,7 @@ channel_input_port_forward_request(int is_root) 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. @@ -1019,149 +2201,148 @@ channel_input_port_forward_request(int is_root) if (port < IPPORT_RESERVED && !is_root) packet_disconnect("Requested forwarding of port %d but user is not root.", port); - /* - * Initiate forwarding, - * bind port to localhost only (gateway ports == 0). - */ - channel_request_local_forwarding(port, hostname, host_port, 0); +#endif + /* Initiate forwarding */ + channel_request_local_forwarding(port, hostname, host_port, gateway_ports); /* Free the argument string. */ xfree(hostname); } /* - * This is called after receiving PORT_OPEN message. This attempts to - * connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION - * or CHANNEL_OPEN_FAILURE. + * 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() +{ + if (num_permitted_opens == 0) + all_opens_permitted = 1; +} -void -channel_input_port_open(int payload_len) +void +channel_add_permitted_opens(char *host, int port) { - int remote_channel, sock = 0, newch, i; - u_short host_port; - char *host, *originator_string; - int host_len, originator_len; - struct addrinfo hints, *ai, *aitop; - char ntop[NI_MAXHOST], strport[NI_MAXSERV]; - int gaierr; + if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) + fatal("channel_request_remote_forwarding: too many forwards"); + debug("allow port forwarding to host %s port %d", host, port); - /* Get remote channel number. */ - remote_channel = packet_get_int(); + permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host); + permitted_opens[num_permitted_opens].port_to_connect = port; + num_permitted_opens++; - /* Get host name to connect to. */ - host = packet_get_string(&host_len); + all_opens_permitted = 0; +} - /* Get port to connect to. */ - host_port = packet_get_int(); +void +channel_clear_permitted_opens(void) +{ + int i; - /* Get remote originator name. */ - if (have_hostname_in_open) { - originator_string = packet_get_string(&originator_len); - originator_len += 4; /* size of packet_int */ - } else { - originator_string = xstrdup("unknown (remote did not supply name)"); - originator_len = 0; /* no originator supplied */ - } + for (i = 0; i < num_permitted_opens; i++) + xfree(permitted_opens[i].host_to_connect); + num_permitted_opens = 0; - packet_integrity_check(payload_len, - 4 + 4 + host_len + 4 + originator_len, - SSH_MSG_PORT_OPEN); +} - /* Check if opening that port is permitted. */ - if (!all_opens_permitted) { - /* Go trough all permitted ports. */ - for (i = 0; i < num_permitted_opens; i++) - if (permitted_opens[i].port == host_port && - strcmp(permitted_opens[i].host, host) == 0) - break; - /* Check if we found the requested port among those permitted. */ - if (i >= num_permitted_opens) { - /* The port is not permitted. */ - log("Received request to connect to %.100s:%d, but the request was denied.", - host, host_port); - packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); - packet_put_int(remote_channel); - packet_send(); - } - } +/* return socket to remote host, port */ +int +connect_to(const char *host, u_short port) +{ + struct addrinfo hints, *ai, *aitop; + char ntop[NI_MAXHOST], strport[NI_MAXSERV]; + int gaierr; + int sock = -1; memset(&hints, 0, sizeof(hints)); hints.ai_family = IPv4or6; hints.ai_socktype = SOCK_STREAM; - snprintf(strport, sizeof strport, "%d", host_port); + snprintf(strport, sizeof strport, "%d", port); if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) { - error("%.100s: unknown host (%s)", host, gai_strerror(gaierr)); - goto fail; + error("connect_to %.100s: unknown host (%s)", host, + 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; if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { - error("channel_input_port_open: getnameinfo failed"); + error("connect_to: getnameinfo failed"); continue; } - /* Create the socket. */ sock = socket(ai->ai_family, SOCK_STREAM, 0); if (sock < 0) { error("socket: %.100s", strerror(errno)); continue; } - /* Connect to the host/port. */ - if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { - error("connect %.100s port %s: %.100s", ntop, strport, + if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0) + fatal("connect_to: F_SETFL: %s", strerror(errno)); + if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 && + errno != EINPROGRESS) { + error("connect_to %.100s port %s: %.100s", ntop, strport, strerror(errno)); close(sock); - continue; /* fail -- try next */ + continue; /* fail -- try next */ } break; /* success */ } freeaddrinfo(aitop); - if (!ai) { - error("connect %.100s port %d: failed.", host, host_port); - goto fail; + error("connect_to %.100s port %d: failed.", host, port); + return -1; } + /* success */ + return sock; +} - /* Successful connection. */ - - /* Allocate a channel for this connection. */ - newch = channel_allocate(SSH_CHANNEL_OPEN, sock, originator_string); - channels[newch].remote_id = remote_channel; - - /* Send a confirmation to the remote host. */ - packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); - packet_put_int(remote_channel); - packet_put_int(newch); - packet_send(); +int +channel_connect_by_listen_adress(u_short listen_port) +{ + int i; - /* Free the argument string. */ - xfree(host); + for (i = 0; i < num_permitted_opens; i++) + if (permitted_opens[i].listen_port == listen_port) + return connect_to( + permitted_opens[i].host_to_connect, + permitted_opens[i].port_to_connect); + error("WARNING: Server requests forwarding for unknown listen_port %d", + listen_port); + return -1; +} - return; +/* Check if connecting to that port is permitted and connect. */ +int +channel_connect_to(const char *host, u_short port) +{ + int i, permit; -fail: - /* Free the argument string. */ - xfree(host); + permit = all_opens_permitted; + if (!permit) { + for (i = 0; i < num_permitted_opens; i++) + if (permitted_opens[i].port_to_connect == port && + strcmp(permitted_opens[i].host_to_connect, host) == 0) + permit = 1; - /* Send refusal to the remote host. */ - packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); - packet_put_int(remote_channel); - packet_send(); + } + if (!permit) { + log("Received request to connect to host %.100s port %d, " + "but the request was denied.", host, port); + return -1; + } + return connect_to(host, port); } +/* -- X11 forwarding */ + /* * Creates an internet domain socket for listening for X11 connections. * Returns a suitable value for the DISPLAY variable, or NULL if an error * occurs. */ - -#define NUM_SOCKS 10 - char * x11_create_display_inet(int screen_number, int x11_display_offset) { @@ -1191,11 +2372,12 @@ x11_create_display_inet(int screen_number, int x11_display_offset) continue; sock = socket(ai->ai_family, SOCK_STREAM, 0); if (sock < 0) { - if (errno != EINVAL) { + if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) { error("socket: %.100s", strerror(errno)); return NULL; } else { - debug("Socket family %d not supported [X11 disp create]", ai->ai_family); + debug("x11_create_display_inet: Socket family %d not supported", + ai->ai_family); continue; } } @@ -1222,6 +2404,7 @@ x11_create_display_inet(int screen_number, int x11_display_offset) break; #endif } + freeaddrinfo(aitop); if (num_socks > 0) break; } @@ -1241,12 +2424,11 @@ x11_create_display_inet(int screen_number, int x11_display_offset) } /* Set up a suitable value for the DISPLAY variable. */ - if (gethostname(hostname, sizeof(hostname)) < 0) fatal("gethostname: %.100s", strerror(errno)); #ifdef IPADDR_IN_DISPLAY - /* + /* * HPUX detects the local hostname in the DISPLAY variable and tries * to set up a shared memory connection to the server, which it * incorrectly supposes to be local. @@ -1275,20 +2457,22 @@ x11_create_display_inet(int screen_number, int x11_display_offset) memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr)); /* Set DISPLAY to :screen.display */ - snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr), - display_number, screen_number); + snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr), + display_number, screen_number); } #else /* IPADDR_IN_DISPLAY */ /* Just set DISPLAY to hostname:screen.display */ snprintf(display, sizeof display, "%.400s:%d.%d", hostname, - display_number, screen_number); + display_number, screen_number); #endif /* IPADDR_IN_DISPLAY */ /* Allocate a channel for each socket. */ for (n = 0; n < num_socks; n++) { sock = socks[n]; - (void) channel_allocate(SSH_CHANNEL_X11_LISTENER, sock, - xstrdup("X11 inet listener")); + (void) channel_new("x11 listener", + SSH_CHANNEL_X11_LISTENER, sock, sock, -1, + CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, + 0, xstrdup("X11 inet listener"), 1); } /* Return a suitable value for the DISPLAY environment variable. */ @@ -1301,7 +2485,7 @@ x11_create_display_inet(int screen_number, int x11_display_offset) static int -connect_local_xsocket(unsigned int dnr) +connect_local_xsocket(u_int dnr) { static const char *const x_sockets[] = { X_UNIX_PATH "%u", @@ -1328,44 +2512,21 @@ connect_local_xsocket(unsigned int dnr) return -1; } - -/* - * This is called when SSH_SMSG_X11_OPEN is received. The packet contains - * the remote channel number. We should do whatever we want, and respond - * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. - */ - -void -x11_input_open(int payload_len) +int +x11_connect_display(void) { - int remote_channel, display_number, sock = 0, newch; + int display_number, sock = 0; const char *display; - char buf[1024], *cp, *remote_host; - int remote_len; + char buf[1024], *cp; struct addrinfo hints, *ai, *aitop; char strport[NI_MAXSERV]; int gaierr; - /* Get remote channel number. */ - remote_channel = packet_get_int(); - - /* Get remote originator name. */ - if (have_hostname_in_open) { - remote_host = packet_get_string(&remote_len); - remote_len += 4; - } else { - remote_host = xstrdup("unknown (remote did not supply name)"); - remote_len = 0; - } - - debug("Received X11 open request."); - packet_integrity_check(payload_len, 4 + remote_len, SSH_SMSG_X11_OPEN); - /* Try to open a socket for the local X server. */ display = getenv("DISPLAY"); if (!display) { error("DISPLAY not set."); - goto fail; + return -1; } /* * Now we decode the value of the DISPLAY variable and make a @@ -1382,15 +2543,15 @@ x11_input_open(int payload_len) if (sscanf(strrchr(display, ':') + 1, "%d", &display_number) != 1) { error("Could not parse display number from DISPLAY: %.100s", display); - goto fail; + return -1; } /* Create a socket. */ sock = connect_local_xsocket(display_number); if (sock < 0) - goto fail; + return -1; /* OK, we now have a connection to the display. */ - goto success; + return sock; } /* * Connect to an inet socket. The DISPLAY value is supposedly @@ -1401,14 +2562,14 @@ x11_input_open(int payload_len) cp = strchr(buf, ':'); if (!cp) { error("Could not find ':' in DISPLAY: %.100s", display); - goto fail; + return -1; } *cp = 0; /* buf now contains the host name. But first we parse the display number. */ if (sscanf(cp + 1, "%d", &display_number) != 1) { error("Could not parse display number from DISPLAY: %.100s", display); - goto fail; + return -1; } /* Look up the host address */ @@ -1418,67 +2579,118 @@ x11_input_open(int payload_len) snprintf(strport, sizeof strport, "%d", 6000 + display_number); if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr)); - goto fail; + return -1; } for (ai = aitop; ai; ai = ai->ai_next) { /* Create a socket. */ sock = socket(ai->ai_family, SOCK_STREAM, 0); if (sock < 0) { debug("socket: %.100s", strerror(errno)); - continue; - } - /* Connect it to the display. */ - if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { - debug("connect %.100s port %d: %.100s", buf, 6000 + display_number, - strerror(errno)); - close(sock); - continue; + continue; + } + /* Connect it to the display. */ + if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { + debug("connect %.100s port %d: %.100s", buf, + 6000 + display_number, strerror(errno)); + close(sock); + continue; + } + /* Success */ + break; } - /* Success */ - break; - - } /* (ai = aitop, ai; ai = ai->ai_next) */ freeaddrinfo(aitop); if (!ai) { - error("connect %.100s port %d: %.100s", buf, 6000 + display_number, + error("connect %.100s port %d: %.100s", buf, 6000 + display_number, strerror(errno)); - goto fail; + return -1; } -success: - /* We have successfully obtained a connection to the real X display. */ + return sock; +} - /* Allocate a channel for this connection. */ - if (x11_saved_proto == NULL) - newch = channel_allocate(SSH_CHANNEL_OPEN, sock, remote_host); - else - newch = channel_allocate(SSH_CHANNEL_X11_OPEN, sock, remote_host); - channels[newch].remote_id = remote_channel; +/* + * 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. + */ - /* Send a confirmation to the remote host. */ - packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); - packet_put_int(remote_channel); - packet_put_int(newch); - packet_send(); +void +x11_input_open(int type, int plen, void *ctxt) +{ + Channel *c = NULL; + int remote_id, sock = 0; + char *remote_host; + + debug("Received X11 open request."); + + remote_id = packet_get_int(); - return; + 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_done(); + + /* 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); + if (c == NULL) { + error("x11_input_open: channel_new failed"); + close(sock); + } else { + c->remote_id = remote_id; + } + } + 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(); +} -fail: - /* Send refusal to the remote host. */ +/* dummy protocol handler that denies SSH-1 requests (agent/x11) */ +void +deny_input_open(int type, int plen, 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 plen %d", type, plen); + break; + } + error("Warning: this is probably a break in attempt by a malicious server."); packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); - packet_put_int(remote_channel); + 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(const char *proto, const char *data) +void +x11_request_forwarding_with_spoofing(int client_session_id, + const char *proto, const char *data) { - unsigned int data_len = (unsigned int) strlen(data) / 2; - unsigned int i, value; + u_int data_len = (u_int) strlen(data) / 2; + u_int i, value, len; char *new_data; int screen_number; const char *cp; @@ -1516,23 +2728,33 @@ x11_request_forwarding_with_spoofing(const char *proto, const char *data) x11_fake_data_len = data_len; /* Convert the fake data into hex. */ - new_data = xmalloc(2 * data_len + 1); + len = 2 * data_len + 1; + new_data = xmalloc(len); for (i = 0; i < data_len; i++) - sprintf(new_data + 2 * i, "%02x", (unsigned char) x11_fake_data[i]); + snprintf(new_data + 2 * i, len - 2 * i, + "%02x", (u_char) x11_fake_data[i]); /* Send the request packet. */ - packet_start(SSH_CMSG_X11_REQUEST_FORWARDING); - packet_put_string(proto, strlen(proto)); - packet_put_string(new_data, strlen(new_data)); + 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 +void auth_request_forwarding() { packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); @@ -1549,51 +2771,63 @@ auth_request_forwarding() char * auth_get_socket_name() { - return channel_forwarded_auth_socket_name; + return auth_sock_name; } /* removes the agent forwarding socket */ -void -cleanup_socket(void) +void +auth_sock_cleanup_proc(void *ignored) { - remove(channel_forwarded_auth_socket_name); - rmdir(channel_forwarded_auth_socket_dir); + if (auth_sock_name) { + unlink(auth_sock_name); + rmdir(auth_sock_dir); + auth_sock_name = NULL; + } } /* - * This if called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server. + * This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server. * This starts forwarding authentication requests. */ -void +int auth_input_request_forwarding(struct passwd * pw) { - int sock, newch; + Channel *nc; + int sock; struct sockaddr_un sunaddr; - if (auth_get_socket_name() != NULL) - fatal("Protocol error: authentication forwarding requested twice."); + if (auth_get_socket_name() != NULL) { + error("authentication forwarding requested twice."); + return 0; + } /* Temporarily drop privileged uid for mkdir/bind. */ - temporarily_use_uid(pw->pw_uid); + temporarily_use_uid(pw); /* Allocate a buffer for the socket name, and format the name. */ - channel_forwarded_auth_socket_name = xmalloc(MAX_SOCKET_NAME); - channel_forwarded_auth_socket_dir = xmalloc(MAX_SOCKET_NAME); - strlcpy(channel_forwarded_auth_socket_dir, "/tmp/ssh-XXXXXXXX", MAX_SOCKET_NAME); + auth_sock_name = xmalloc(MAXPATHLEN); + auth_sock_dir = xmalloc(MAXPATHLEN); + strlcpy(auth_sock_dir, "/tmp/ssh-XXXXXXXX", MAXPATHLEN); /* Create private directory for socket */ - if (mkdtemp(channel_forwarded_auth_socket_dir) == NULL) - packet_disconnect("mkdtemp: %.100s", strerror(errno)); - snprintf(channel_forwarded_auth_socket_name, MAX_SOCKET_NAME, "%s/agent.%d", - channel_forwarded_auth_socket_dir, (int) getpid()); - - if (atexit(cleanup_socket) < 0) { - int saved = errno; - cleanup_socket(); - packet_disconnect("socket: %.100s", strerror(saved)); + if (mkdtemp(auth_sock_dir) == NULL) { + packet_send_debug("Agent forwarding disabled: " + "mkdtemp() failed: %.100s", strerror(errno)); + restore_uid(); + xfree(auth_sock_name); + xfree(auth_sock_dir); + auth_sock_name = NULL; + auth_sock_dir = NULL; + return 0; } + snprintf(auth_sock_name, MAXPATHLEN, "%s/agent.%d", + auth_sock_dir, (int) getpid()); + + /* delete agent socket on fatal() */ + fatal_add_cleanup(auth_sock_cleanup_proc, NULL); + /* Create the socket. */ sock = socket(AF_UNIX, SOCK_STREAM, 0); if (sock < 0) @@ -1602,7 +2836,7 @@ auth_input_request_forwarding(struct passwd * pw) /* Bind it to the name. */ memset(&sunaddr, 0, sizeof(sunaddr)); sunaddr.sun_family = AF_UNIX; - strncpy(sunaddr.sun_path, channel_forwarded_auth_socket_name, + strncpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path)); if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) @@ -1616,22 +2850,33 @@ auth_input_request_forwarding(struct passwd * pw) packet_disconnect("listen: %.100s", strerror(errno)); /* Allocate a channel for the authentication agent socket. */ - newch = channel_allocate(SSH_CHANNEL_AUTH_SOCKET, sock, - xstrdup("auth socket")); - strlcpy(channels[newch].path, channel_forwarded_auth_socket_name, - sizeof(channels[newch].path)); + nc = channel_new("auth socket", + SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1, + CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, + 0, xstrdup("auth socket"), 1); + if (nc == NULL) { + error("auth_input_request_forwarding: channel_new failed"); + auth_sock_cleanup_proc(NULL); + close(sock); + return 0; + } + strlcpy(nc->path, auth_sock_name, sizeof(nc->path)); + return 1; } /* This is called to process an SSH_SMSG_AGENT_OPEN message. */ -void -auth_input_open_request() +void +auth_input_open_request(int type, int plen, void *ctxt) { - int remch, sock, newch; - char *dummyname; + Channel *c = NULL; + int remote_id, sock; + char *name; + + packet_integrity_check(plen, 4, type); /* Read the remote channel number from the message. */ - remch = packet_get_int(); + remote_id = packet_get_int(); /* * Get a connection to the local authentication agent (this may again @@ -1645,27 +2890,27 @@ auth_input_open_request() * because authentication forwarding is only enabled if we have an * agent. */ - if (sock < 0) { + if (sock >= 0) { + name = xstrdup("authentication agent connection"); + c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, + -1, 0, 0, 0, name, 1); + if (c == NULL) { + error("auth_input_open_request: channel_new failed"); + xfree(name); + close(sock); + } else { + c->remote_id = remote_id; + } + } + if (c == NULL) { packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); - packet_put_int(remch); - packet_send(); - return; + packet_put_int(remote_id); + } else { + /* Send a confirmation to the remote host. */ + debug("Forwarding authentication connection."); + packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); + packet_put_int(remote_id); + packet_put_int(c->self); } - debug("Forwarding authentication connection."); - - /* - * Dummy host name. This will be freed when the channel is freed; it - * will still be valid in the packet_put_string below since the - * channel cannot yet be freed at that point. - */ - dummyname = xstrdup("authentication agent connection"); - - newch = channel_allocate(SSH_CHANNEL_OPEN, sock, dummyname); - channels[newch].remote_id = remch; - - /* Send a confirmation to the remote host. */ - packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); - packet_put_int(remch); - packet_put_int(newch); packet_send(); }