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Diffstat (limited to 'crypto/openssh/channels.c')
-rw-r--r-- | crypto/openssh/channels.c | 3227 |
1 files changed, 3227 insertions, 0 deletions
diff --git a/crypto/openssh/channels.c b/crypto/openssh/channels.c new file mode 100644 index 0000000..26b63a1 --- /dev/null +++ b/crypto/openssh/channels.c @@ -0,0 +1,3227 @@ +/* $OpenBSD: channels.c,v 1.266 2006/08/29 10:40:18 djm Exp $ */ +/* + * Author: Tatu Ylonen <ylo@cs.hut.fi> + * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland + * All rights reserved + * This file contains functions for generic socket connection forwarding. + * There is also code for initiating connection forwarding for X11 connections, + * arbitrary tcp/ip connections, and the authentication agent connection. + * + * As far as I am concerned, the code I have written for this software + * can be used freely for any purpose. Any derived versions of this + * software must be clearly marked as such, and if the derived work is + * incompatible with the protocol description in the RFC file, it must be + * called by a name other than "ssh" or "Secure Shell". + * + * SSH2 support added by Markus Friedl. + * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. + * Copyright (c) 1999 Dug Song. All rights reserved. + * Copyright (c) 1999 Theo de Raadt. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "includes.h" + +#include <sys/types.h> +#include <sys/ioctl.h> +#include <sys/un.h> +#include <sys/socket.h> +#ifdef HAVE_SYS_TIME_H +# include <sys/time.h> +#endif + +#include <netinet/in.h> +#include <arpa/inet.h> + +#include <errno.h> +#include <netdb.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <termios.h> +#include <unistd.h> +#include <stdarg.h> + +#include "xmalloc.h" +#include "ssh.h" +#include "ssh1.h" +#include "ssh2.h" +#include "packet.h" +#include "log.h" +#include "misc.h" +#include "buffer.h" +#include "channels.h" +#include "compat.h" +#include "canohost.h" +#include "key.h" +#include "authfd.h" +#include "pathnames.h" + +/* -- channel core */ + +/* + * Pointer to an array containing all allocated channels. The array is + * dynamically extended as needed. + */ +static Channel **channels = NULL; + +/* + * Size of the channel array. All slots of the array must always be + * initialized (at least the type field); unused slots set to NULL + */ +static u_int channels_alloc = 0; + +/* + * Maximum file descriptor value used in any of the channels. This is + * updated in channel_new. + */ +static int channel_max_fd = 0; + + +/* -- tcp forwarding */ + +/* + * Data structure for storing which hosts are permitted for forward requests. + * The local sides of any remote forwards are stored in this array to prevent + * a corrupt remote server from accessing arbitrary TCP/IP ports on our local + * network (which might be behind a firewall). + */ +typedef struct { + char *host_to_connect; /* Connect to 'host'. */ + u_short port_to_connect; /* Connect to 'port'. */ + u_short listen_port; /* Remote side should listen port number. */ +} ForwardPermission; + +/* List of all permitted host/port pairs to connect by the user. */ +static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION]; + +/* List of all permitted host/port pairs to connect by the admin. */ +static ForwardPermission permitted_adm_opens[SSH_MAX_FORWARDS_PER_DIRECTION]; + +/* Number of permitted host/port pairs in the array permitted by the user. */ +static int num_permitted_opens = 0; + +/* Number of permitted host/port pair in the array permitted by the admin. */ +static int num_adm_permitted_opens = 0; + +/* + * If this is true, all opens are permitted. This is the case on the server + * on which we have to trust the client anyway, and the user could do + * anything after logging in anyway. + */ +static int all_opens_permitted = 0; + + +/* -- X11 forwarding */ + +/* Maximum number of fake X11 displays to try. */ +#define MAX_DISPLAYS 1000 + +/* Saved X11 local (client) display. */ +static char *x11_saved_display = NULL; + +/* Saved X11 authentication protocol name. */ +static char *x11_saved_proto = NULL; + +/* Saved X11 authentication data. This is the real data. */ +static char *x11_saved_data = NULL; +static u_int x11_saved_data_len = 0; + +/* + * Fake X11 authentication data. This is what the server will be sending us; + * we should replace any occurrences of this by the real data. + */ +static u_char *x11_fake_data = NULL; +static u_int x11_fake_data_len; + + +/* -- agent forwarding */ + +#define NUM_SOCKS 10 + +/* AF_UNSPEC or AF_INET or AF_INET6 */ +static int IPv4or6 = AF_UNSPEC; + +/* helper */ +static void port_open_helper(Channel *c, char *rtype); + +/* -- channel core */ + +Channel * +channel_by_id(int id) +{ + Channel *c; + + if (id < 0 || (u_int)id >= channels_alloc) { + logit("channel_by_id: %d: bad id", id); + return NULL; + } + c = channels[id]; + if (c == NULL) { + logit("channel_by_id: %d: bad id: channel free", id); + return NULL; + } + return c; +} + +/* + * Returns the channel if it is allowed to receive protocol messages. + * Private channels, like listening sockets, may not receive messages. + */ +Channel * +channel_lookup(int id) +{ + Channel *c; + + if ((c = channel_by_id(id)) == NULL) + return (NULL); + + switch (c->type) { + case SSH_CHANNEL_X11_OPEN: + case SSH_CHANNEL_LARVAL: + case SSH_CHANNEL_CONNECTING: + case SSH_CHANNEL_DYNAMIC: + case SSH_CHANNEL_OPENING: + case SSH_CHANNEL_OPEN: + case SSH_CHANNEL_INPUT_DRAINING: + case SSH_CHANNEL_OUTPUT_DRAINING: + return (c); + } + logit("Non-public channel %d, type %d.", id, c->type); + return (NULL); +} + +/* + * Register filedescriptors for a channel, used when allocating a channel or + * when the channel consumer/producer is ready, e.g. shell exec'd + */ +static void +channel_register_fds(Channel *c, int rfd, int wfd, int efd, + int extusage, int nonblock) +{ + /* Update the maximum file descriptor value. */ + channel_max_fd = MAX(channel_max_fd, rfd); + channel_max_fd = MAX(channel_max_fd, wfd); + channel_max_fd = MAX(channel_max_fd, efd); + + /* XXX set close-on-exec -markus */ + + c->rfd = rfd; + c->wfd = wfd; + c->sock = (rfd == wfd) ? rfd : -1; + c->ctl_fd = -1; /* XXX: set elsewhere */ + c->efd = efd; + c->extended_usage = extusage; + + /* XXX ugly hack: nonblock is only set by the server */ + if (nonblock && isatty(c->rfd)) { + debug2("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; + } + c->wfd_isatty = isatty(c->wfd); + + /* enable nonblocking mode */ + if (nonblock) { + if (rfd != -1) + set_nonblock(rfd); + if (wfd != -1) + set_nonblock(wfd); + if (efd != -1) + set_nonblock(efd); + } +} + +/* + * Allocate a new channel object and set its type and socket. This will cause + * remote_name to be freed. + */ +Channel * +channel_new(char *ctype, int type, int rfd, int wfd, int efd, + u_int window, u_int maxpack, int extusage, char *remote_name, int nonblock) +{ + int found; + u_int i; + Channel *c; + + /* Do initial allocation if this is the first call. */ + if (channels_alloc == 0) { + channels_alloc = 10; + channels = xcalloc(channels_alloc, sizeof(Channel *)); + for (i = 0; i < channels_alloc; i++) + channels[i] = NULL; + } + /* Try to find a free slot where to put the new channel. */ + for (found = -1, i = 0; i < channels_alloc; i++) + if (channels[i] == NULL) { + /* Found a free slot. */ + found = (int)i; + break; + } + if (found < 0) { + /* There are no free slots. Take last+1 slot and expand the array. */ + found = channels_alloc; + if (channels_alloc > 10000) + fatal("channel_new: internal error: channels_alloc %d " + "too big.", channels_alloc); + channels = xrealloc(channels, channels_alloc + 10, + sizeof(Channel *)); + channels_alloc += 10; + debug2("channel: expanding %d", channels_alloc); + for (i = found; i < channels_alloc; i++) + channels[i] = NULL; + } + /* Initialize and return new channel. */ + c = channels[found] = xcalloc(1, sizeof(Channel)); + buffer_init(&c->input); + buffer_init(&c->output); + buffer_init(&c->extended); + c->ostate = CHAN_OUTPUT_OPEN; + c->istate = CHAN_INPUT_OPEN; + c->flags = 0; + channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); + c->self = found; + c->type = type; + c->ctype = ctype; + c->local_window = window; + c->local_window_max = window; + c->local_consumed = 0; + c->local_maxpacket = maxpack; + c->remote_id = -1; + c->remote_name = xstrdup(remote_name); + c->remote_window = 0; + c->remote_maxpacket = 0; + c->force_drain = 0; + c->single_connection = 0; + c->detach_user = NULL; + c->detach_close = 0; + c->confirm = NULL; + c->confirm_ctx = NULL; + c->input_filter = NULL; + c->output_filter = NULL; + debug("channel %d: new [%s]", found, remote_name); + return c; +} + +static int +channel_find_maxfd(void) +{ + u_int i; + int max = 0; + Channel *c; + + for (i = 0; i < channels_alloc; i++) { + c = channels[i]; + if (c != NULL) { + max = MAX(max, c->rfd); + max = MAX(max, c->wfd); + max = MAX(max, c->efd); + } + } + return max; +} + +int +channel_close_fd(int *fdp) +{ + int ret = 0, fd = *fdp; + + if (fd != -1) { + ret = close(fd); + *fdp = -1; + if (fd == channel_max_fd) + channel_max_fd = channel_find_maxfd(); + } + return ret; +} + +/* Close all channel fd/socket. */ +static void +channel_close_fds(Channel *c) +{ + debug3("channel %d: close_fds r %d w %d e %d c %d", + c->self, c->rfd, c->wfd, c->efd, c->ctl_fd); + + channel_close_fd(&c->sock); + channel_close_fd(&c->ctl_fd); + channel_close_fd(&c->rfd); + channel_close_fd(&c->wfd); + channel_close_fd(&c->efd); +} + +/* Free the channel and close its fd/socket. */ +void +channel_free(Channel *c) +{ + char *s; + u_int i, n; + + for (n = 0, i = 0; i < channels_alloc; i++) + if (channels[i]) + n++; + debug("channel %d: free: %s, nchannels %u", c->self, + c->remote_name ? c->remote_name : "???", n); + + s = channel_open_message(); + debug3("channel %d: status: %s", c->self, s); + xfree(s); + + if (c->sock != -1) + shutdown(c->sock, SHUT_RDWR); + if (c->ctl_fd != -1) + shutdown(c->ctl_fd, SHUT_RDWR); + channel_close_fds(c); + buffer_free(&c->input); + buffer_free(&c->output); + buffer_free(&c->extended); + if (c->remote_name) { + xfree(c->remote_name); + c->remote_name = NULL; + } + channels[c->self] = NULL; + xfree(c); +} + +void +channel_free_all(void) +{ + u_int i; + + for (i = 0; i < channels_alloc; i++) + if (channels[i] != NULL) + channel_free(channels[i]); +} + +/* + * Closes the sockets/fds of all channels. This is used to close extra file + * descriptors after a fork. + */ +void +channel_close_all(void) +{ + u_int i; + + for (i = 0; i < channels_alloc; i++) + if (channels[i] != NULL) + channel_close_fds(channels[i]); +} + +/* + * Stop listening to channels. + */ +void +channel_stop_listening(void) +{ + u_int i; + Channel *c; + + for (i = 0; i < channels_alloc; i++) { + c = channels[i]; + if (c != NULL) { + switch (c->type) { + case SSH_CHANNEL_AUTH_SOCKET: + case SSH_CHANNEL_PORT_LISTENER: + case SSH_CHANNEL_RPORT_LISTENER: + case SSH_CHANNEL_X11_LISTENER: + channel_close_fd(&c->sock); + channel_free(c); + break; + } + } + } +} + +/* + * Returns true if no channel has too much buffered data, and false if one or + * more channel is overfull. + */ +int +channel_not_very_much_buffered_data(void) +{ + u_int i; + Channel *c; + + for (i = 0; i < channels_alloc; i++) { + c = channels[i]; + if (c != NULL && c->type == SSH_CHANNEL_OPEN) { +#if 0 + if (!compat20 && + buffer_len(&c->input) > packet_get_maxsize()) { + debug2("channel %d: big input buffer %d", + c->self, buffer_len(&c->input)); + return 0; + } +#endif + if (buffer_len(&c->output) > packet_get_maxsize()) { + debug2("channel %d: big output buffer %u > %u", + c->self, buffer_len(&c->output), + packet_get_maxsize()); + return 0; + } + } + } + return 1; +} + +/* Returns true if any channel is still open. */ +int +channel_still_open(void) +{ + u_int i; + Channel *c; + + for (i = 0; i < channels_alloc; i++) { + c = channels[i]; + if (c == NULL) + continue; + switch (c->type) { + case SSH_CHANNEL_X11_LISTENER: + case SSH_CHANNEL_PORT_LISTENER: + case SSH_CHANNEL_RPORT_LISTENER: + case SSH_CHANNEL_CLOSED: + case SSH_CHANNEL_AUTH_SOCKET: + case SSH_CHANNEL_DYNAMIC: + case SSH_CHANNEL_CONNECTING: + case SSH_CHANNEL_ZOMBIE: + continue; + case SSH_CHANNEL_LARVAL: + if (!compat20) + fatal("cannot happen: SSH_CHANNEL_LARVAL"); + continue; + case SSH_CHANNEL_OPENING: + case SSH_CHANNEL_OPEN: + case SSH_CHANNEL_X11_OPEN: + return 1; + case SSH_CHANNEL_INPUT_DRAINING: + case SSH_CHANNEL_OUTPUT_DRAINING: + if (!compat13) + fatal("cannot happen: OUT_DRAIN"); + return 1; + default: + fatal("channel_still_open: bad channel type %d", c->type); + /* NOTREACHED */ + } + } + return 0; +} + +/* Returns the id of an open channel suitable for keepaliving */ +int +channel_find_open(void) +{ + u_int i; + Channel *c; + + for (i = 0; i < channels_alloc; i++) { + c = channels[i]; + if (c == NULL || c->remote_id < 0) + continue; + switch (c->type) { + case SSH_CHANNEL_CLOSED: + case SSH_CHANNEL_DYNAMIC: + case SSH_CHANNEL_X11_LISTENER: + case SSH_CHANNEL_PORT_LISTENER: + case SSH_CHANNEL_RPORT_LISTENER: + case SSH_CHANNEL_OPENING: + case SSH_CHANNEL_CONNECTING: + case SSH_CHANNEL_ZOMBIE: + continue; + case SSH_CHANNEL_LARVAL: + case SSH_CHANNEL_AUTH_SOCKET: + case SSH_CHANNEL_OPEN: + case SSH_CHANNEL_X11_OPEN: + return i; + case SSH_CHANNEL_INPUT_DRAINING: + case SSH_CHANNEL_OUTPUT_DRAINING: + if (!compat13) + fatal("cannot happen: OUT_DRAIN"); + return i; + default: + fatal("channel_find_open: bad channel type %d", c->type); + /* NOTREACHED */ + } + } + return -1; +} + + +/* + * Returns a message describing the currently open forwarded connections, + * suitable for sending to the client. The message contains crlf pairs for + * newlines. + */ +char * +channel_open_message(void) +{ + Buffer buffer; + Channel *c; + char buf[1024], *cp; + u_int i; + + buffer_init(&buffer); + snprintf(buf, sizeof buf, "The following connections are open:\r\n"); + buffer_append(&buffer, buf, strlen(buf)); + for (i = 0; i < channels_alloc; i++) { + c = channels[i]; + if (c == NULL) + continue; + switch (c->type) { + case SSH_CHANNEL_X11_LISTENER: + case SSH_CHANNEL_PORT_LISTENER: + case SSH_CHANNEL_RPORT_LISTENER: + case SSH_CHANNEL_CLOSED: + case SSH_CHANNEL_AUTH_SOCKET: + case SSH_CHANNEL_ZOMBIE: + continue; + case SSH_CHANNEL_LARVAL: + case SSH_CHANNEL_OPENING: + case SSH_CHANNEL_CONNECTING: + case SSH_CHANNEL_DYNAMIC: + case SSH_CHANNEL_OPEN: + case SSH_CHANNEL_X11_OPEN: + case SSH_CHANNEL_INPUT_DRAINING: + case SSH_CHANNEL_OUTPUT_DRAINING: + snprintf(buf, sizeof buf, + " #%d %.300s (t%d r%d i%d/%d o%d/%d fd %d/%d cfd %d)\r\n", + c->self, c->remote_name, + c->type, c->remote_id, + c->istate, buffer_len(&c->input), + c->ostate, buffer_len(&c->output), + c->rfd, c->wfd, c->ctl_fd); + buffer_append(&buffer, buf, strlen(buf)); + continue; + default: + fatal("channel_open_message: bad channel type %d", c->type); + /* NOTREACHED */ + } + } + buffer_append(&buffer, "\0", 1); + cp = xstrdup(buffer_ptr(&buffer)); + buffer_free(&buffer); + return cp; +} + +void +channel_send_open(int id) +{ + Channel *c = channel_lookup(id); + + if (c == NULL) { + logit("channel_send_open: %d: bad id", id); + return; + } + debug2("channel %d: send open", id); + packet_start(SSH2_MSG_CHANNEL_OPEN); + packet_put_cstring(c->ctype); + packet_put_int(c->self); + packet_put_int(c->local_window); + packet_put_int(c->local_maxpacket); + packet_send(); +} + +void +channel_request_start(int id, char *service, int wantconfirm) +{ + Channel *c = channel_lookup(id); + + if (c == NULL) { + logit("channel_request_start: %d: unknown channel id", id); + return; + } + debug2("channel %d: request %s confirm %d", id, service, wantconfirm); + packet_start(SSH2_MSG_CHANNEL_REQUEST); + packet_put_int(c->remote_id); + packet_put_cstring(service); + packet_put_char(wantconfirm); +} + +void +channel_register_confirm(int id, channel_callback_fn *fn, void *ctx) +{ + Channel *c = channel_lookup(id); + + if (c == NULL) { + logit("channel_register_comfirm: %d: bad id", id); + return; + } + c->confirm = fn; + c->confirm_ctx = ctx; +} + +void +channel_register_cleanup(int id, channel_callback_fn *fn, int do_close) +{ + Channel *c = channel_by_id(id); + + if (c == NULL) { + logit("channel_register_cleanup: %d: bad id", id); + return; + } + c->detach_user = fn; + c->detach_close = do_close; +} + +void +channel_cancel_cleanup(int id) +{ + Channel *c = channel_by_id(id); + + if (c == NULL) { + logit("channel_cancel_cleanup: %d: bad id", id); + return; + } + c->detach_user = NULL; + c->detach_close = 0; +} + +void +channel_register_filter(int id, channel_infilter_fn *ifn, + channel_outfilter_fn *ofn) +{ + Channel *c = channel_lookup(id); + + if (c == NULL) { + logit("channel_register_filter: %d: bad id", id); + return; + } + c->input_filter = ifn; + c->output_filter = ofn; +} + +void +channel_set_fds(int id, int rfd, int wfd, int efd, + int extusage, int nonblock, u_int window_max) +{ + Channel *c = channel_lookup(id); + + if (c == NULL || c->type != SSH_CHANNEL_LARVAL) + fatal("channel_activate for non-larval channel %d.", id); + channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); + c->type = SSH_CHANNEL_OPEN; + c->local_window = c->local_window_max = window_max; + packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); + packet_put_int(c->remote_id); + packet_put_int(c->local_window); + packet_send(); +} + +/* + * 'channel_pre*' are called just before select() to add any bits relevant to + * channels in the select bitmasks. + */ +/* + * 'channel_post*': perform any appropriate operations for channels which + * have events pending. + */ +typedef void chan_fn(Channel *c, fd_set *readset, fd_set *writeset); +chan_fn *channel_pre[SSH_CHANNEL_MAX_TYPE]; +chan_fn *channel_post[SSH_CHANNEL_MAX_TYPE]; + +/* ARGSUSED */ +static void +channel_pre_listener(Channel *c, fd_set *readset, fd_set *writeset) +{ + FD_SET(c->sock, readset); +} + +/* ARGSUSED */ +static void +channel_pre_connecting(Channel *c, fd_set *readset, fd_set *writeset) +{ + debug3("channel %d: waiting for connection", c->self); + FD_SET(c->sock, writeset); +} + +static void +channel_pre_open_13(Channel *c, fd_set *readset, fd_set *writeset) +{ + if (buffer_len(&c->input) < packet_get_maxsize()) + FD_SET(c->sock, readset); + if (buffer_len(&c->output) > 0) + FD_SET(c->sock, writeset); +} + +static void +channel_pre_open(Channel *c, fd_set *readset, fd_set *writeset) +{ + u_int limit = compat20 ? c->remote_window : packet_get_maxsize(); + + if (c->istate == CHAN_INPUT_OPEN && + limit > 0 && + buffer_len(&c->input) < limit && + buffer_check_alloc(&c->input, CHAN_RBUF)) + FD_SET(c->rfd, readset); + if (c->ostate == CHAN_OUTPUT_OPEN || + c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { + if (buffer_len(&c->output) > 0) { + FD_SET(c->wfd, writeset); + } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) { + if (CHANNEL_EFD_OUTPUT_ACTIVE(c)) + debug2("channel %d: obuf_empty delayed efd %d/(%d)", + c->self, c->efd, buffer_len(&c->extended)); + else + chan_obuf_empty(c); + } + } + /** XXX check close conditions, too */ + if (compat20 && c->efd != -1) { + if (c->extended_usage == CHAN_EXTENDED_WRITE && + buffer_len(&c->extended) > 0) + FD_SET(c->efd, writeset); + else if (!(c->flags & CHAN_EOF_SENT) && + c->extended_usage == CHAN_EXTENDED_READ && + buffer_len(&c->extended) < c->remote_window) + FD_SET(c->efd, readset); + } + /* XXX: What about efd? races? */ + if (compat20 && c->ctl_fd != -1 && + c->istate == CHAN_INPUT_OPEN && c->ostate == CHAN_OUTPUT_OPEN) + FD_SET(c->ctl_fd, readset); +} + +/* ARGSUSED */ +static void +channel_pre_input_draining(Channel *c, fd_set *readset, fd_set *writeset) +{ + if (buffer_len(&c->input) == 0) { + packet_start(SSH_MSG_CHANNEL_CLOSE); + packet_put_int(c->remote_id); + packet_send(); + c->type = SSH_CHANNEL_CLOSED; + debug2("channel %d: closing after input drain.", c->self); + } +} + +/* ARGSUSED */ +static void +channel_pre_output_draining(Channel *c, fd_set *readset, fd_set *writeset) +{ + if (buffer_len(&c->output) == 0) + chan_mark_dead(c); + else + FD_SET(c->sock, writeset); +} + +/* + * This is a special state for X11 authentication spoofing. An opened X11 + * connection (when authentication spoofing is being done) remains in this + * state until the first packet has been completely read. The authentication + * data in that packet is then substituted by the real data if it matches the + * fake data, and the channel is put into normal mode. + * XXX All this happens at the client side. + * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok + */ +static int +x11_open_helper(Buffer *b) +{ + u_char *ucp; + u_int proto_len, data_len; + + /* Check if the fixed size part of the packet is in buffer. */ + if (buffer_len(b) < 12) + return 0; + + /* Parse the lengths of variable-length fields. */ + ucp = buffer_ptr(b); + if (ucp[0] == 0x42) { /* Byte order MSB first. */ + proto_len = 256 * ucp[6] + ucp[7]; + data_len = 256 * ucp[8] + ucp[9]; + } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */ + proto_len = ucp[6] + 256 * ucp[7]; + data_len = ucp[8] + 256 * ucp[9]; + } else { + debug2("Initial X11 packet contains bad byte order byte: 0x%x", + ucp[0]); + return -1; + } + + /* Check if the whole packet is in buffer. */ + if (buffer_len(b) < + 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3)) + return 0; + + /* Check if authentication protocol matches. */ + if (proto_len != strlen(x11_saved_proto) || + memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) { + debug2("X11 connection uses different authentication protocol."); + return -1; + } + /* Check if authentication data matches our fake data. */ + if (data_len != x11_fake_data_len || + memcmp(ucp + 12 + ((proto_len + 3) & ~3), + x11_fake_data, x11_fake_data_len) != 0) { + debug2("X11 auth data does not match fake data."); + return -1; + } + /* Check fake data length */ + if (x11_fake_data_len != x11_saved_data_len) { + error("X11 fake_data_len %d != saved_data_len %d", + x11_fake_data_len, x11_saved_data_len); + return -1; + } + /* + * Received authentication protocol and data match + * our fake data. Substitute the fake data with real + * data. + */ + memcpy(ucp + 12 + ((proto_len + 3) & ~3), + x11_saved_data, x11_saved_data_len); + return 1; +} + +static void +channel_pre_x11_open_13(Channel *c, fd_set *readset, fd_set *writeset) +{ + int ret = x11_open_helper(&c->output); + + if (ret == 1) { + /* Start normal processing for the channel. */ + c->type = SSH_CHANNEL_OPEN; + channel_pre_open_13(c, readset, writeset); + } else if (ret == -1) { + /* + * We have received an X11 connection that has bad + * authentication information. + */ + logit("X11 connection rejected because of wrong authentication."); + buffer_clear(&c->input); + buffer_clear(&c->output); + channel_close_fd(&c->sock); + c->sock = -1; + c->type = SSH_CHANNEL_CLOSED; + packet_start(SSH_MSG_CHANNEL_CLOSE); + packet_put_int(c->remote_id); + packet_send(); + } +} + +static void +channel_pre_x11_open(Channel *c, fd_set *readset, fd_set *writeset) +{ + int ret = x11_open_helper(&c->output); + + /* c->force_drain = 1; */ + + if (ret == 1) { + c->type = SSH_CHANNEL_OPEN; + channel_pre_open(c, readset, writeset); + } else if (ret == -1) { + logit("X11 connection rejected because of wrong authentication."); + debug2("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate); + chan_read_failed(c); + buffer_clear(&c->input); + chan_ibuf_empty(c); + buffer_clear(&c->output); + /* for proto v1, the peer will send an IEOF */ + if (compat20) + chan_write_failed(c); + else + c->type = SSH_CHANNEL_OPEN; + debug2("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate); + } +} + +/* try to decode a socks4 header */ +/* ARGSUSED */ +static int +channel_decode_socks4(Channel *c, fd_set *readset, fd_set *writeset) +{ + char *p, *host; + u_int len, have, i, found; + char username[256]; + struct { + u_int8_t version; + u_int8_t command; + u_int16_t dest_port; + struct in_addr dest_addr; + } s4_req, s4_rsp; + + debug2("channel %d: decode socks4", c->self); + + have = buffer_len(&c->input); + len = sizeof(s4_req); + if (have < len) + return 0; + p = buffer_ptr(&c->input); + for (found = 0, i = len; i < have; i++) { + if (p[i] == '\0') { + found = 1; + break; + } + if (i > 1024) { + /* the peer is probably sending garbage */ + debug("channel %d: decode socks4: too long", + c->self); + return -1; + } + } + if (!found) + return 0; + buffer_get(&c->input, (char *)&s4_req.version, 1); + buffer_get(&c->input, (char *)&s4_req.command, 1); + buffer_get(&c->input, (char *)&s4_req.dest_port, 2); + buffer_get(&c->input, (char *)&s4_req.dest_addr, 4); + have = buffer_len(&c->input); + p = buffer_ptr(&c->input); + len = strlen(p); + debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); + if (len > have) + fatal("channel %d: decode socks4: len %d > have %d", + c->self, len, have); + strlcpy(username, p, sizeof(username)); + buffer_consume(&c->input, len); + buffer_consume(&c->input, 1); /* trailing '\0' */ + + host = inet_ntoa(s4_req.dest_addr); + strlcpy(c->path, host, sizeof(c->path)); + c->host_port = ntohs(s4_req.dest_port); + + debug2("channel %d: dynamic request: socks4 host %s port %u command %u", + c->self, host, c->host_port, s4_req.command); + + if (s4_req.command != 1) { + debug("channel %d: cannot handle: socks4 cn %d", + c->self, s4_req.command); + return -1; + } + s4_rsp.version = 0; /* vn: 0 for reply */ + s4_rsp.command = 90; /* cd: req granted */ + s4_rsp.dest_port = 0; /* ignored */ + s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ + buffer_append(&c->output, &s4_rsp, sizeof(s4_rsp)); + return 1; +} + +/* try to decode a socks5 header */ +#define SSH_SOCKS5_AUTHDONE 0x1000 +#define SSH_SOCKS5_NOAUTH 0x00 +#define SSH_SOCKS5_IPV4 0x01 +#define SSH_SOCKS5_DOMAIN 0x03 +#define SSH_SOCKS5_IPV6 0x04 +#define SSH_SOCKS5_CONNECT 0x01 +#define SSH_SOCKS5_SUCCESS 0x00 + +/* ARGSUSED */ +static int +channel_decode_socks5(Channel *c, fd_set *readset, fd_set *writeset) +{ + struct { + u_int8_t version; + u_int8_t command; + u_int8_t reserved; + u_int8_t atyp; + } s5_req, s5_rsp; + u_int16_t dest_port; + u_char *p, dest_addr[255+1]; + u_int have, need, i, found, nmethods, addrlen, af; + + debug2("channel %d: decode socks5", c->self); + p = buffer_ptr(&c->input); + if (p[0] != 0x05) + return -1; + have = buffer_len(&c->input); + if (!(c->flags & SSH_SOCKS5_AUTHDONE)) { + /* format: ver | nmethods | methods */ + if (have < 2) + return 0; + nmethods = p[1]; + if (have < nmethods + 2) + return 0; + /* look for method: "NO AUTHENTICATION REQUIRED" */ + for (found = 0, i = 2 ; i < nmethods + 2; i++) { + if (p[i] == SSH_SOCKS5_NOAUTH) { + found = 1; + break; + } + } + if (!found) { + debug("channel %d: method SSH_SOCKS5_NOAUTH not found", + c->self); + return -1; + } + buffer_consume(&c->input, nmethods + 2); + buffer_put_char(&c->output, 0x05); /* version */ + buffer_put_char(&c->output, SSH_SOCKS5_NOAUTH); /* method */ + FD_SET(c->sock, writeset); + c->flags |= SSH_SOCKS5_AUTHDONE; + debug2("channel %d: socks5 auth done", c->self); + return 0; /* need more */ + } + debug2("channel %d: socks5 post auth", c->self); + if (have < sizeof(s5_req)+1) + return 0; /* need more */ + memcpy(&s5_req, p, sizeof(s5_req)); + if (s5_req.version != 0x05 || + s5_req.command != SSH_SOCKS5_CONNECT || + s5_req.reserved != 0x00) { + debug2("channel %d: only socks5 connect supported", c->self); + return -1; + } + switch (s5_req.atyp){ + case SSH_SOCKS5_IPV4: + addrlen = 4; + af = AF_INET; + break; + case SSH_SOCKS5_DOMAIN: + addrlen = p[sizeof(s5_req)]; + af = -1; + break; + case SSH_SOCKS5_IPV6: + addrlen = 16; + af = AF_INET6; + break; + default: + debug2("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); + return -1; + } + need = sizeof(s5_req) + addrlen + 2; + if (s5_req.atyp == SSH_SOCKS5_DOMAIN) + need++; + if (have < need) + return 0; + buffer_consume(&c->input, sizeof(s5_req)); + if (s5_req.atyp == SSH_SOCKS5_DOMAIN) + buffer_consume(&c->input, 1); /* host string length */ + buffer_get(&c->input, (char *)&dest_addr, addrlen); + buffer_get(&c->input, (char *)&dest_port, 2); + dest_addr[addrlen] = '\0'; + if (s5_req.atyp == SSH_SOCKS5_DOMAIN) + strlcpy(c->path, (char *)dest_addr, sizeof(c->path)); + else if (inet_ntop(af, dest_addr, c->path, sizeof(c->path)) == NULL) + return -1; + c->host_port = ntohs(dest_port); + + debug2("channel %d: dynamic request: socks5 host %s port %u command %u", + c->self, c->path, c->host_port, s5_req.command); + + s5_rsp.version = 0x05; + s5_rsp.command = SSH_SOCKS5_SUCCESS; + s5_rsp.reserved = 0; /* ignored */ + s5_rsp.atyp = SSH_SOCKS5_IPV4; + ((struct in_addr *)&dest_addr)->s_addr = INADDR_ANY; + dest_port = 0; /* ignored */ + + buffer_append(&c->output, &s5_rsp, sizeof(s5_rsp)); + buffer_append(&c->output, &dest_addr, sizeof(struct in_addr)); + buffer_append(&c->output, &dest_port, sizeof(dest_port)); + return 1; +} + +/* dynamic port forwarding */ +static void +channel_pre_dynamic(Channel *c, fd_set *readset, fd_set *writeset) +{ + u_char *p; + u_int have; + int ret; + + have = buffer_len(&c->input); + c->delayed = 0; + debug2("channel %d: pre_dynamic: have %d", c->self, have); + /* buffer_dump(&c->input); */ + /* check if the fixed size part of the packet is in buffer. */ + if (have < 3) { + /* need more */ + FD_SET(c->sock, readset); + return; + } + /* try to guess the protocol */ + p = buffer_ptr(&c->input); + switch (p[0]) { + case 0x04: + ret = channel_decode_socks4(c, readset, writeset); + break; + case 0x05: + ret = channel_decode_socks5(c, readset, writeset); + break; + default: + ret = -1; + break; + } + if (ret < 0) { + chan_mark_dead(c); + } else if (ret == 0) { + debug2("channel %d: pre_dynamic: need more", c->self); + /* need more */ + FD_SET(c->sock, readset); + } else { + /* switch to the next state */ + c->type = SSH_CHANNEL_OPENING; + port_open_helper(c, "direct-tcpip"); + } +} + +/* This is our fake X11 server socket. */ +/* ARGSUSED */ +static void +channel_post_x11_listener(Channel *c, fd_set *readset, fd_set *writeset) +{ + Channel *nc; + struct sockaddr 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 (c->single_connection) { + debug2("single_connection: closing X11 listener."); + channel_close_fd(&c->sock); + chan_mark_dead(c); + } + if (newsock < 0) { + error("accept: %.100s", strerror(errno)); + return; + } + set_nodelay(newsock); + remote_ipaddr = get_peer_ipaddr(newsock); + remote_port = get_peer_port(newsock); + snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", + remote_ipaddr, remote_port); + + nc = channel_new("accepted x11 socket", + SSH_CHANNEL_OPENING, newsock, newsock, -1, + c->local_window_max, c->local_maxpacket, 0, buf, 1); + if (compat20) { + packet_start(SSH2_MSG_CHANNEL_OPEN); + packet_put_cstring("x11"); + packet_put_int(nc->self); + packet_put_int(nc->local_window_max); + packet_put_int(nc->local_maxpacket); + /* originator ipaddr and port */ + packet_put_cstring(remote_ipaddr); + if (datafellows & SSH_BUG_X11FWD) { + debug2("ssh2 x11 bug compat mode"); + } else { + packet_put_int(remote_port); + } + packet_send(); + } else { + packet_start(SSH_SMSG_X11_OPEN); + packet_put_int(nc->self); + if (packet_get_protocol_flags() & + SSH_PROTOFLAG_HOST_IN_FWD_OPEN) + packet_put_cstring(buf); + packet_send(); + } + xfree(remote_ipaddr); + } +} + +static void +port_open_helper(Channel *c, char *rtype) +{ + int direct; + char buf[1024]; + char *remote_ipaddr = get_peer_ipaddr(c->sock); + int remote_port = get_peer_port(c->sock); + + direct = (strcmp(rtype, "direct-tcpip") == 0); + + snprintf(buf, sizeof buf, + "%s: listening port %d for %.100s port %d, " + "connect from %.200s port %d", + rtype, c->listening_port, c->path, c->host_port, + remote_ipaddr, remote_port); + + xfree(c->remote_name); + c->remote_name = xstrdup(buf); + + if (compat20) { + packet_start(SSH2_MSG_CHANNEL_OPEN); + packet_put_cstring(rtype); + packet_put_int(c->self); + packet_put_int(c->local_window_max); + packet_put_int(c->local_maxpacket); + if (direct) { + /* target host, port */ + packet_put_cstring(c->path); + packet_put_int(c->host_port); + } else { + /* listen address, port */ + packet_put_cstring(c->path); + packet_put_int(c->listening_port); + } + /* originator host and port */ + packet_put_cstring(remote_ipaddr); + packet_put_int((u_int)remote_port); + packet_send(); + } else { + packet_start(SSH_MSG_PORT_OPEN); + packet_put_int(c->self); + packet_put_cstring(c->path); + packet_put_int(c->host_port); + if (packet_get_protocol_flags() & + SSH_PROTOFLAG_HOST_IN_FWD_OPEN) + packet_put_cstring(c->remote_name); + packet_send(); + } + xfree(remote_ipaddr); +} + +static void +channel_set_reuseaddr(int fd) +{ + int on = 1; + + /* + * Set socket options. + * Allow local port reuse in TIME_WAIT. + */ + if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1) + error("setsockopt SO_REUSEADDR fd %d: %s", fd, strerror(errno)); +} + +/* + * This socket is listening for connections to a forwarded TCP/IP port. + */ +/* ARGSUSED */ +static void +channel_post_port_listener(Channel *c, fd_set *readset, fd_set *writeset) +{ + Channel *nc; + struct sockaddr addr; + int newsock, nextstate; + socklen_t addrlen; + char *rtype; + + if (FD_ISSET(c->sock, readset)) { + debug("Connection to port %d forwarding " + "to %.100s port %d requested.", + c->listening_port, c->path, c->host_port); + + if (c->type == SSH_CHANNEL_RPORT_LISTENER) { + nextstate = SSH_CHANNEL_OPENING; + rtype = "forwarded-tcpip"; + } else { + if (c->host_port == 0) { + nextstate = SSH_CHANNEL_DYNAMIC; + rtype = "dynamic-tcpip"; + } else { + nextstate = SSH_CHANNEL_OPENING; + rtype = "direct-tcpip"; + } + } + + addrlen = sizeof(addr); + newsock = accept(c->sock, &addr, &addrlen); + if (newsock < 0) { + error("accept: %.100s", strerror(errno)); + return; + } + set_nodelay(newsock); + nc = channel_new(rtype, nextstate, newsock, newsock, -1, + c->local_window_max, c->local_maxpacket, 0, rtype, 1); + nc->listening_port = c->listening_port; + nc->host_port = c->host_port; + strlcpy(nc->path, c->path, sizeof(nc->path)); + + if (nextstate == SSH_CHANNEL_DYNAMIC) { + /* + * do not call the channel_post handler until + * this flag has been reset by a pre-handler. + * otherwise the FD_ISSET calls might overflow + */ + nc->delayed = 1; + } else { + port_open_helper(nc, rtype); + } + } +} + +/* + * This is the authentication agent socket listening for connections from + * clients. + */ +/* ARGSUSED */ +static void +channel_post_auth_listener(Channel *c, fd_set *readset, fd_set *writeset) +{ + Channel *nc; + int newsock; + struct sockaddr 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; + } + nc = channel_new("accepted auth socket", + SSH_CHANNEL_OPENING, newsock, newsock, -1, + c->local_window_max, c->local_maxpacket, + 0, "accepted auth socket", 1); + if (compat20) { + packet_start(SSH2_MSG_CHANNEL_OPEN); + packet_put_cstring("auth-agent@openssh.com"); + packet_put_int(nc->self); + packet_put_int(c->local_window_max); + packet_put_int(c->local_maxpacket); + } else { + packet_start(SSH_SMSG_AGENT_OPEN); + packet_put_int(nc->self); + } + packet_send(); + } +} + +/* ARGSUSED */ +static void +channel_post_connecting(Channel *c, fd_set *readset, fd_set *writeset) +{ + int err = 0; + socklen_t sz = sizeof(err); + + if (FD_ISSET(c->sock, writeset)) { + if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &err, &sz) < 0) { + err = errno; + error("getsockopt SO_ERROR failed"); + } + if (err == 0) { + debug("channel %d: connected", 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(); + } +} + +/* ARGSUSED */ +static int +channel_handle_rfd(Channel *c, fd_set *readset, fd_set *writeset) +{ + char buf[CHAN_RBUF]; + int len; + + if (c->rfd != -1 && + FD_ISSET(c->rfd, readset)) { + errno = 0; + len = read(c->rfd, buf, sizeof(buf)); + if (len < 0 && (errno == EINTR || errno == EAGAIN)) + return 1; +#ifndef PTY_ZEROREAD + if (len <= 0) { +#else + if ((!c->isatty && len <= 0) || + (c->isatty && (len < 0 || (len == 0 && errno != 0)))) { +#endif + debug2("channel %d: read<=0 rfd %d len %d", + c->self, c->rfd, len); + if (c->type != SSH_CHANNEL_OPEN) { + debug2("channel %d: not open", c->self); + chan_mark_dead(c); + return -1; + } else if (compat13) { + buffer_clear(&c->output); + c->type = SSH_CHANNEL_INPUT_DRAINING; + debug2("channel %d: input draining.", c->self); + } else { + chan_read_failed(c); + } + return -1; + } + if (c->input_filter != NULL) { + if (c->input_filter(c, buf, len) == -1) { + debug2("channel %d: filter stops", c->self); + chan_read_failed(c); + } + } else if (c->datagram) { + buffer_put_string(&c->input, buf, len); + } else { + buffer_append(&c->input, buf, len); + } + } + return 1; +} + +/* ARGSUSED */ +static int +channel_handle_wfd(Channel *c, fd_set *readset, fd_set *writeset) +{ + struct termios tio; + u_char *data = NULL, *buf; + u_int dlen; + int len; + + /* Send buffered output data to the socket. */ + if (c->wfd != -1 && + FD_ISSET(c->wfd, writeset) && + buffer_len(&c->output) > 0) { + if (c->output_filter != NULL) { + if ((buf = c->output_filter(c, &data, &dlen)) == NULL) { + debug2("channel %d: filter stops", c->self); + if (c->type != SSH_CHANNEL_OPEN) + chan_mark_dead(c); + else + chan_write_failed(c); + return -1; + } + } else if (c->datagram) { + buf = data = buffer_get_string(&c->output, &dlen); + } else { + buf = data = buffer_ptr(&c->output); + dlen = buffer_len(&c->output); + } + + if (c->datagram) { + /* ignore truncated writes, datagrams might get lost */ + c->local_consumed += dlen + 4; + len = write(c->wfd, buf, dlen); + xfree(data); + if (len < 0 && (errno == EINTR || errno == EAGAIN)) + return 1; + if (len <= 0) { + if (c->type != SSH_CHANNEL_OPEN) + chan_mark_dead(c); + else + chan_write_failed(c); + return -1; + } + return 1; + } +#ifdef _AIX + /* XXX: Later AIX versions can't push as much data to tty */ + if (compat20 && c->wfd_isatty) + dlen = MIN(dlen, 8*1024); +#endif + + len = write(c->wfd, buf, dlen); + if (len < 0 && (errno == EINTR || errno == EAGAIN)) + return 1; + if (len <= 0) { + if (c->type != SSH_CHANNEL_OPEN) { + debug2("channel %d: not open", c->self); + chan_mark_dead(c); + return -1; + } else if (compat13) { + buffer_clear(&c->output); + debug2("channel %d: input draining.", c->self); + c->type = SSH_CHANNEL_INPUT_DRAINING; + } else { + chan_write_failed(c); + } + return -1; + } + if (compat20 && c->isatty && dlen >= 1 && buf[0] != '\r') { + if (tcgetattr(c->wfd, &tio) == 0 && + !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { + /* + * Simulate echo to reduce the impact of + * traffic analysis. We need to match the + * size of a SSH2_MSG_CHANNEL_DATA message + * (4 byte channel id + buf) + */ + packet_send_ignore(4 + len); + packet_send(); + } + } + buffer_consume(&c->output, len); + if (compat20 && len > 0) { + c->local_consumed += len; + } + } + return 1; +} + +static int +channel_handle_efd(Channel *c, fd_set *readset, fd_set *writeset) +{ + char buf[CHAN_RBUF]; + int len; + +/** XXX handle drain efd, too */ + if (c->efd != -1) { + if (c->extended_usage == CHAN_EXTENDED_WRITE && + FD_ISSET(c->efd, writeset) && + buffer_len(&c->extended) > 0) { + len = write(c->efd, buffer_ptr(&c->extended), + buffer_len(&c->extended)); + debug2("channel %d: written %d to efd %d", + c->self, len, c->efd); + if (len < 0 && (errno == EINTR || errno == EAGAIN)) + return 1; + if (len <= 0) { + debug2("channel %d: closing write-efd %d", + c->self, c->efd); + channel_close_fd(&c->efd); + } else { + buffer_consume(&c->extended, len); + c->local_consumed += len; + } + } else if (c->extended_usage == CHAN_EXTENDED_READ && + FD_ISSET(c->efd, readset)) { + len = read(c->efd, buf, sizeof(buf)); + debug2("channel %d: read %d from efd %d", + c->self, len, c->efd); + if (len < 0 && (errno == EINTR || errno == EAGAIN)) + return 1; + if (len <= 0) { + debug2("channel %d: closing read-efd %d", + c->self, c->efd); + channel_close_fd(&c->efd); + } else { + buffer_append(&c->extended, buf, len); + } + } + } + return 1; +} + +/* ARGSUSED */ +static int +channel_handle_ctl(Channel *c, fd_set *readset, fd_set *writeset) +{ + char buf[16]; + int len; + + /* Monitor control fd to detect if the slave client exits */ + if (c->ctl_fd != -1 && FD_ISSET(c->ctl_fd, readset)) { + len = read(c->ctl_fd, buf, sizeof(buf)); + if (len < 0 && (errno == EINTR || errno == EAGAIN)) + return 1; + if (len <= 0) { + debug2("channel %d: ctl read<=0", c->self); + if (c->type != SSH_CHANNEL_OPEN) { + debug2("channel %d: not open", c->self); + chan_mark_dead(c); + return -1; + } else { + chan_read_failed(c); + chan_write_failed(c); + } + return -1; + } else + fatal("%s: unexpected data on ctl fd", __func__); + } + return 1; +} + +static int +channel_check_window(Channel *c) +{ + if (c->type == SSH_CHANNEL_OPEN && + !(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && + c->local_window < c->local_window_max/2 && + c->local_consumed > 0) { + packet_start(SSH2_MSG_CHANNEL_WINDOW_ADJUST); + packet_put_int(c->remote_id); + packet_put_int(c->local_consumed); + packet_send(); + debug2("channel %d: window %d sent adjust %d", + c->self, c->local_window, + c->local_consumed); + c->local_window += c->local_consumed; + c->local_consumed = 0; + } + return 1; +} + +static void +channel_post_open(Channel *c, fd_set *readset, fd_set *writeset) +{ + if (c->delayed) + return; + channel_handle_rfd(c, readset, writeset); + channel_handle_wfd(c, readset, writeset); + if (!compat20) + return; + channel_handle_efd(c, readset, writeset); + channel_handle_ctl(c, readset, writeset); + channel_check_window(c); +} + +/* ARGSUSED */ +static void +channel_post_output_drain_13(Channel *c, fd_set *readset, fd_set *writeset) +{ + int len; + + /* Send buffered output data to the socket. */ + if (FD_ISSET(c->sock, writeset) && buffer_len(&c->output) > 0) { + len = write(c->sock, buffer_ptr(&c->output), + buffer_len(&c->output)); + if (len <= 0) + buffer_clear(&c->output); + else + buffer_consume(&c->output, len); + } +} + +static void +channel_handler_init_20(void) +{ + channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; + channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; + channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; + channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; + channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; + channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; + channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; + channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; + + channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; + channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; + channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; + channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; + channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; + channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; + channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; +} + +static void +channel_handler_init_13(void) +{ + channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_13; + channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open_13; + channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; + channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; + channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; + channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining; + channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining; + channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; + channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; + + channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; + channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; + channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; + channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; + channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13; + channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; + channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; +} + +static void +channel_handler_init_15(void) +{ + channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open; + channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; + channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; + channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; + channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; + channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; + channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; + + channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; + channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; + channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; + channel_post[SSH_CHANNEL_OPEN] = &channel_post_open; + channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; + channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open; +} + +static void +channel_handler_init(void) +{ + int i; + + for (i = 0; i < SSH_CHANNEL_MAX_TYPE; i++) { + channel_pre[i] = NULL; + channel_post[i] = NULL; + } + if (compat20) + channel_handler_init_20(); + else if (compat13) + channel_handler_init_13(); + else + channel_handler_init_15(); +} + +/* gc dead channels */ +static void +channel_garbage_collect(Channel *c) +{ + if (c == NULL) + return; + if (c->detach_user != NULL) { + if (!chan_is_dead(c, c->detach_close)) + return; + debug2("channel %d: gc: notify user", c->self); + c->detach_user(c->self, NULL); + /* if we still have a callback */ + if (c->detach_user != NULL) + return; + debug2("channel %d: gc: user detached", c->self); + } + if (!chan_is_dead(c, 1)) + return; + debug2("channel %d: garbage collecting", c->self); + channel_free(c); +} + +static void +channel_handler(chan_fn *ftab[], fd_set *readset, fd_set *writeset) +{ + static int did_init = 0; + u_int i; + Channel *c; + + if (!did_init) { + channel_handler_init(); + did_init = 1; + } + for (i = 0; i < channels_alloc; i++) { + c = channels[i]; + if (c == NULL) + continue; + if (ftab[c->type] != NULL) + (*ftab[c->type])(c, readset, writeset); + channel_garbage_collect(c); + } +} + +/* + * Allocate/update select bitmasks and add any bits relevant to channels in + * select bitmasks. + */ +void +channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp, + u_int *nallocp, int rekeying) +{ + u_int n, sz, nfdset; + + n = MAX(*maxfdp, channel_max_fd); + + nfdset = howmany(n+1, NFDBITS); + /* Explicitly test here, because xrealloc isn't always called */ + if (nfdset && SIZE_T_MAX / nfdset < sizeof(fd_mask)) + fatal("channel_prepare_select: max_fd (%d) is too large", n); + sz = nfdset * sizeof(fd_mask); + + /* perhaps check sz < nalloc/2 and shrink? */ + if (*readsetp == NULL || sz > *nallocp) { + *readsetp = xrealloc(*readsetp, nfdset, sizeof(fd_mask)); + *writesetp = xrealloc(*writesetp, nfdset, sizeof(fd_mask)); + *nallocp = sz; + } + *maxfdp = n; + memset(*readsetp, 0, sz); + memset(*writesetp, 0, sz); + + if (!rekeying) + channel_handler(channel_pre, *readsetp, *writesetp); +} + +/* + * After select, perform any appropriate operations for channels which have + * events pending. + */ +void +channel_after_select(fd_set *readset, fd_set *writeset) +{ + channel_handler(channel_post, readset, writeset); +} + + +/* If there is data to send to the connection, enqueue some of it now. */ +void +channel_output_poll(void) +{ + Channel *c; + u_int i, len; + + for (i = 0; i < channels_alloc; i++) { + c = channels[i]; + if (c == NULL) + continue; + + /* + * We are only interested in channels that can have buffered + * incoming data. + */ + if (compat13) { + if (c->type != SSH_CHANNEL_OPEN && + c->type != SSH_CHANNEL_INPUT_DRAINING) + continue; + } else { + if (c->type != SSH_CHANNEL_OPEN) + continue; + } + if (compat20 && + (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { + /* XXX is this true? */ + debug3("channel %d: will not send data after close", c->self); + continue; + } + + /* Get the amount of buffered data for this channel. */ + if ((c->istate == CHAN_INPUT_OPEN || + c->istate == CHAN_INPUT_WAIT_DRAIN) && + (len = buffer_len(&c->input)) > 0) { + if (c->datagram) { + if (len > 0) { + u_char *data; + u_int dlen; + + data = buffer_get_string(&c->input, + &dlen); + packet_start(SSH2_MSG_CHANNEL_DATA); + packet_put_int(c->remote_id); + packet_put_string(data, dlen); + packet_send(); + c->remote_window -= dlen + 4; + xfree(data); + } + continue; + } + /* + * Send some data for the other side over the secure + * connection. + */ + if (compat20) { + if (len > c->remote_window) + len = c->remote_window; + if (len > c->remote_maxpacket) + len = c->remote_maxpacket; + } else { + if (packet_is_interactive()) { + if (len > 1024) + len = 512; + } else { + /* Keep the packets at reasonable size. */ + if (len > packet_get_maxsize()/2) + len = packet_get_maxsize()/2; + } + } + if (len > 0) { + packet_start(compat20 ? + SSH2_MSG_CHANNEL_DATA : SSH_MSG_CHANNEL_DATA); + packet_put_int(c->remote_id); + packet_put_string(buffer_ptr(&c->input), len); + packet_send(); + buffer_consume(&c->input, len); + c->remote_window -= len; + } + } else if (c->istate == CHAN_INPUT_WAIT_DRAIN) { + if (compat13) + fatal("cannot happen: istate == INPUT_WAIT_DRAIN for proto 1.3"); + /* + * input-buffer is empty and read-socket shutdown: + * tell peer, that we will not send more data: send IEOF. + * hack for extended data: delay EOF if EFD still in use. + */ + if (CHANNEL_EFD_INPUT_ACTIVE(c)) + debug2("channel %d: ibuf_empty delayed efd %d/(%d)", + c->self, c->efd, buffer_len(&c->extended)); + else + chan_ibuf_empty(c); + } + /* Send extended data, i.e. stderr */ + if (compat20 && + !(c->flags & CHAN_EOF_SENT) && + c->remote_window > 0 && + (len = buffer_len(&c->extended)) > 0 && + c->extended_usage == CHAN_EXTENDED_READ) { + debug2("channel %d: rwin %u elen %u euse %d", + c->self, c->remote_window, buffer_len(&c->extended), + c->extended_usage); + if (len > c->remote_window) + len = c->remote_window; + if (len > c->remote_maxpacket) + len = c->remote_maxpacket; + packet_start(SSH2_MSG_CHANNEL_EXTENDED_DATA); + packet_put_int(c->remote_id); + packet_put_int(SSH2_EXTENDED_DATA_STDERR); + packet_put_string(buffer_ptr(&c->extended), len); + packet_send(); + buffer_consume(&c->extended, len); + c->remote_window -= len; + debug2("channel %d: sent ext data %d", c->self, len); + } + } +} + + +/* -- protocol input */ + +/* ARGSUSED */ +void +channel_input_data(int type, u_int32_t seq, void *ctxt) +{ + int id; + char *data; + u_int data_len; + Channel *c; + + /* Get the channel number and verify it. */ + id = packet_get_int(); + c = channel_lookup(id); + if (c == NULL) + packet_disconnect("Received data for nonexistent channel %d.", id); + + /* Ignore any data for non-open channels (might happen on close) */ + if (c->type != SSH_CHANNEL_OPEN && + c->type != SSH_CHANNEL_X11_OPEN) + return; + + /* Get the data. */ + data = packet_get_string(&data_len); + + /* + * Ignore data for protocol > 1.3 if output end is no longer open. + * For protocol 2 the sending side is reducing its window as it sends + * data, so we must 'fake' consumption of the data in order to ensure + * that window updates are sent back. Otherwise the connection might + * deadlock. + */ + if (!compat13 && c->ostate != CHAN_OUTPUT_OPEN) { + if (compat20) { + c->local_window -= data_len; + c->local_consumed += data_len; + } + xfree(data); + return; + } + + if (compat20) { + if (data_len > c->local_maxpacket) { + logit("channel %d: rcvd big packet %d, maxpack %d", + c->self, data_len, c->local_maxpacket); + } + if (data_len > c->local_window) { + logit("channel %d: rcvd too much data %d, win %d", + c->self, data_len, c->local_window); + xfree(data); + return; + } + c->local_window -= data_len; + } + packet_check_eom(); + if (c->datagram) + buffer_put_string(&c->output, data, data_len); + else + buffer_append(&c->output, data, data_len); + xfree(data); +} + +/* ARGSUSED */ +void +channel_input_extended_data(int type, u_int32_t seq, void *ctxt) +{ + int id; + char *data; + u_int data_len, tcode; + Channel *c; + + /* Get the channel number and verify it. */ + id = packet_get_int(); + c = channel_lookup(id); + + if (c == NULL) + packet_disconnect("Received extended_data for bad channel %d.", id); + if (c->type != SSH_CHANNEL_OPEN) { + logit("channel %d: ext data for non open", id); + return; + } + if (c->flags & CHAN_EOF_RCVD) { + if (datafellows & SSH_BUG_EXTEOF) + debug("channel %d: accepting ext data after eof", id); + else + packet_disconnect("Received extended_data after EOF " + "on channel %d.", id); + } + tcode = packet_get_int(); + if (c->efd == -1 || + c->extended_usage != CHAN_EXTENDED_WRITE || + tcode != SSH2_EXTENDED_DATA_STDERR) { + logit("channel %d: bad ext data", c->self); + return; + } + data = packet_get_string(&data_len); + packet_check_eom(); + if (data_len > c->local_window) { + logit("channel %d: rcvd too much extended_data %d, win %d", + c->self, data_len, c->local_window); + xfree(data); + return; + } + debug2("channel %d: rcvd ext data %d", c->self, data_len); + c->local_window -= data_len; + buffer_append(&c->extended, data, data_len); + xfree(data); +} + +/* ARGSUSED */ +void +channel_input_ieof(int type, u_int32_t seq, void *ctxt) +{ + int id; + Channel *c; + + id = packet_get_int(); + packet_check_eom(); + c = channel_lookup(id); + if (c == NULL) + packet_disconnect("Received ieof for nonexistent channel %d.", id); + chan_rcvd_ieof(c); + + /* XXX force input close */ + if (c->force_drain && c->istate == CHAN_INPUT_OPEN) { + debug("channel %d: FORCE input drain", c->self); + c->istate = CHAN_INPUT_WAIT_DRAIN; + if (buffer_len(&c->input) == 0) + chan_ibuf_empty(c); + } + +} + +/* ARGSUSED */ +void +channel_input_close(int type, u_int32_t seq, void *ctxt) +{ + int id; + Channel *c; + + id = packet_get_int(); + packet_check_eom(); + c = channel_lookup(id); + if (c == NULL) + packet_disconnect("Received close for nonexistent channel %d.", id); + + /* + * Send a confirmation that we have closed the channel and no more + * data is coming for it. + */ + packet_start(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION); + packet_put_int(c->remote_id); + packet_send(); + + /* + * If the channel is in closed state, we have sent a close request, + * and the other side will eventually respond with a confirmation. + * Thus, we cannot free the channel here, because then there would be + * no-one to receive the confirmation. The channel gets freed when + * the confirmation arrives. + */ + if (c->type != SSH_CHANNEL_CLOSED) { + /* + * Not a closed channel - mark it as draining, which will + * cause it to be freed later. + */ + buffer_clear(&c->input); + c->type = SSH_CHANNEL_OUTPUT_DRAINING; + } +} + +/* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ +/* ARGSUSED */ +void +channel_input_oclose(int type, u_int32_t seq, void *ctxt) +{ + int id = packet_get_int(); + Channel *c = channel_lookup(id); + + packet_check_eom(); + if (c == NULL) + packet_disconnect("Received oclose for nonexistent channel %d.", id); + chan_rcvd_oclose(c); +} + +/* ARGSUSED */ +void +channel_input_close_confirmation(int type, u_int32_t seq, void *ctxt) +{ + int id = packet_get_int(); + Channel *c = channel_lookup(id); + + packet_check_eom(); + if (c == NULL) + packet_disconnect("Received close confirmation for " + "out-of-range channel %d.", id); + if (c->type != SSH_CHANNEL_CLOSED) + packet_disconnect("Received close confirmation for " + "non-closed channel %d (type %d).", id, c->type); + channel_free(c); +} + +/* ARGSUSED */ +void +channel_input_open_confirmation(int type, u_int32_t seq, void *ctxt) +{ + int id, remote_id; + Channel *c; + + id = packet_get_int(); + c = channel_lookup(id); + + if (c==NULL || c->type != SSH_CHANNEL_OPENING) + packet_disconnect("Received open confirmation for " + "non-opening channel %d.", id); + remote_id = packet_get_int(); + /* Record the remote channel number and mark that the channel is now open. */ + c->remote_id = remote_id; + c->type = SSH_CHANNEL_OPEN; + + if (compat20) { + c->remote_window = packet_get_int(); + c->remote_maxpacket = packet_get_int(); + if (c->confirm) { + debug2("callback start"); + c->confirm(c->self, c->confirm_ctx); + debug2("callback done"); + } + debug2("channel %d: open confirm rwindow %u rmax %u", c->self, + c->remote_window, c->remote_maxpacket); + } + packet_check_eom(); +} + +static char * +reason2txt(int reason) +{ + switch (reason) { + case SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED: + return "administratively prohibited"; + case SSH2_OPEN_CONNECT_FAILED: + return "connect failed"; + case SSH2_OPEN_UNKNOWN_CHANNEL_TYPE: + return "unknown channel type"; + case SSH2_OPEN_RESOURCE_SHORTAGE: + return "resource shortage"; + } + return "unknown reason"; +} + +/* ARGSUSED */ +void +channel_input_open_failure(int type, u_int32_t seq, void *ctxt) +{ + int id, reason; + char *msg = NULL, *lang = NULL; + Channel *c; + + id = packet_get_int(); + c = channel_lookup(id); + + if (c==NULL || c->type != SSH_CHANNEL_OPENING) + packet_disconnect("Received open failure for " + "non-opening channel %d.", id); + if (compat20) { + reason = packet_get_int(); + if (!(datafellows & SSH_BUG_OPENFAILURE)) { + msg = packet_get_string(NULL); + lang = packet_get_string(NULL); + } + logit("channel %d: open failed: %s%s%s", id, + reason2txt(reason), msg ? ": ": "", msg ? msg : ""); + if (msg != NULL) + xfree(msg); + if (lang != NULL) + xfree(lang); + } + packet_check_eom(); + /* Free the channel. This will also close the socket. */ + channel_free(c); +} + +/* ARGSUSED */ +void +channel_input_window_adjust(int type, u_int32_t seq, void *ctxt) +{ + Channel *c; + int id; + u_int adjust; + + if (!compat20) + return; + + /* Get the channel number and verify it. */ + id = packet_get_int(); + c = channel_lookup(id); + + if (c == NULL) { + logit("Received window adjust for non-open channel %d.", id); + return; + } + adjust = packet_get_int(); + packet_check_eom(); + debug2("channel %d: rcvd adjust %u", id, adjust); + c->remote_window += adjust; +} + +/* ARGSUSED */ +void +channel_input_port_open(int type, u_int32_t seq, void *ctxt) +{ + Channel *c = NULL; + u_short host_port; + char *host, *originator_string; + int remote_id, sock = -1; + + remote_id = packet_get_int(); + host = packet_get_string(NULL); + host_port = packet_get_int(); + + if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { + originator_string = packet_get_string(NULL); + } else { + originator_string = xstrdup("unknown (remote did not supply name)"); + } + packet_check_eom(); + 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); + c->remote_id = remote_id; + } + xfree(originator_string); + if (c == NULL) { + packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); + packet_put_int(remote_id); + packet_send(); + } + xfree(host); +} + + +/* -- tcp forwarding */ + +void +channel_set_af(int af) +{ + IPv4or6 = af; +} + +static int +channel_setup_fwd_listener(int type, const char *listen_addr, u_short listen_port, + const char *host_to_connect, u_short port_to_connect, int gateway_ports) +{ + Channel *c; + int sock, r, success = 0, wildcard = 0, is_client; + struct addrinfo hints, *ai, *aitop; + const char *host, *addr; + char ntop[NI_MAXHOST], strport[NI_MAXSERV]; + + host = (type == SSH_CHANNEL_RPORT_LISTENER) ? + listen_addr : host_to_connect; + is_client = (type == SSH_CHANNEL_PORT_LISTENER); + + if (host == NULL) { + error("No forward host name."); + return 0; + } + if (strlen(host) > SSH_CHANNEL_PATH_LEN - 1) { + error("Forward host name too long."); + return 0; + } + + /* + * Determine whether or not a port forward listens to loopback, + * specified address or wildcard. On the client, a specified bind + * address will always override gateway_ports. On the server, a + * gateway_ports of 1 (``yes'') will override the client's + * specification and force a wildcard bind, whereas a value of 2 + * (``clientspecified'') will bind to whatever address the client + * asked for. + * + * Special-case listen_addrs are: + * + * "0.0.0.0" -> wildcard v4/v6 if SSH_OLD_FORWARD_ADDR + * "" (empty string), "*" -> wildcard v4/v6 + * "localhost" -> loopback v4/v6 + */ + addr = NULL; + if (listen_addr == NULL) { + /* No address specified: default to gateway_ports setting */ + if (gateway_ports) + wildcard = 1; + } else if (gateway_ports || is_client) { + if (((datafellows & SSH_OLD_FORWARD_ADDR) && + strcmp(listen_addr, "0.0.0.0") == 0) || + *listen_addr == '\0' || strcmp(listen_addr, "*") == 0 || + (!is_client && gateway_ports == 1)) + wildcard = 1; + else if (strcmp(listen_addr, "localhost") != 0) + addr = listen_addr; + } + + debug3("channel_setup_fwd_listener: type %d wildcard %d addr %s", + type, wildcard, (addr == NULL) ? "NULL" : addr); + + /* + * getaddrinfo returns a loopback address if the hostname is + * set to NULL and hints.ai_flags is not AI_PASSIVE + */ + memset(&hints, 0, sizeof(hints)); + hints.ai_family = IPv4or6; + hints.ai_flags = wildcard ? AI_PASSIVE : 0; + hints.ai_socktype = SOCK_STREAM; + snprintf(strport, sizeof strport, "%d", listen_port); + if ((r = getaddrinfo(addr, strport, &hints, &aitop)) != 0) { + if (addr == NULL) { + /* This really shouldn't happen */ + packet_disconnect("getaddrinfo: fatal error: %s", + gai_strerror(r)); + } else { + error("channel_setup_fwd_listener: " + "getaddrinfo(%.64s): %s", addr, gai_strerror(r)); + } + return 0; + } + + for (ai = aitop; ai; ai = ai->ai_next) { + if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) + continue; + if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), + strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { + error("channel_setup_fwd_listener: getnameinfo failed"); + continue; + } + /* Create a port to listen for the host. */ + sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); + if (sock < 0) { + /* this is no error since kernel may not support ipv6 */ + verbose("socket: %.100s", strerror(errno)); + continue; + } + + channel_set_reuseaddr(sock); + + debug("Local forwarding listening on %s port %s.", ntop, strport); + + /* Bind the socket to the address. */ + if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { + /* address can be in use ipv6 address is already bound */ + if (!ai->ai_next) + error("bind: %.100s", strerror(errno)); + else + verbose("bind: %.100s", strerror(errno)); + + close(sock); + continue; + } + /* Start listening for connections on the socket. */ + if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { + error("listen: %.100s", strerror(errno)); + close(sock); + continue; + } + /* Allocate a channel number for the socket. */ + c = channel_new("port listener", type, sock, sock, -1, + CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, + 0, "port listener", 1); + strlcpy(c->path, host, sizeof(c->path)); + c->host_port = port_to_connect; + c->listening_port = listen_port; + success = 1; + } + if (success == 0) + error("channel_setup_fwd_listener: cannot listen to port: %d", + listen_port); + freeaddrinfo(aitop); + return success; +} + +int +channel_cancel_rport_listener(const char *host, u_short port) +{ + u_int i; + int found = 0; + + for (i = 0; i < channels_alloc; i++) { + Channel *c = channels[i]; + + if (c != NULL && c->type == SSH_CHANNEL_RPORT_LISTENER && + strncmp(c->path, host, sizeof(c->path)) == 0 && + c->listening_port == port) { + debug2("%s: close channel %d", __func__, i); + channel_free(c); + found = 1; + } + } + + return (found); +} + +/* protocol local port fwd, used by ssh (and sshd in v1) */ +int +channel_setup_local_fwd_listener(const char *listen_host, u_short listen_port, + const char *host_to_connect, u_short port_to_connect, int gateway_ports) +{ + return channel_setup_fwd_listener(SSH_CHANNEL_PORT_LISTENER, + listen_host, listen_port, host_to_connect, port_to_connect, + gateway_ports); +} + +/* protocol v2 remote port fwd, used by sshd */ +int +channel_setup_remote_fwd_listener(const char *listen_address, + u_short listen_port, int gateway_ports) +{ + return channel_setup_fwd_listener(SSH_CHANNEL_RPORT_LISTENER, + listen_address, listen_port, NULL, 0, gateway_ports); +} + +/* + * Initiate forwarding of connections to port "port" on remote host through + * the secure channel to host:port from local side. + */ + +int +channel_request_remote_forwarding(const char *listen_host, u_short listen_port, + const char *host_to_connect, u_short port_to_connect) +{ + int type, success = 0; + + /* Record locally that connection to this host/port is permitted. */ + if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) + fatal("channel_request_remote_forwarding: too many forwards"); + + /* Send the forward request to the remote side. */ + if (compat20) { + const char *address_to_bind; + if (listen_host == NULL) + address_to_bind = "localhost"; + else if (*listen_host == '\0' || strcmp(listen_host, "*") == 0) + address_to_bind = ""; + else + address_to_bind = listen_host; + + packet_start(SSH2_MSG_GLOBAL_REQUEST); + packet_put_cstring("tcpip-forward"); + packet_put_char(1); /* boolean: want reply */ + packet_put_cstring(address_to_bind); + packet_put_int(listen_port); + packet_send(); + packet_write_wait(); + /* Assume that server accepts the request */ + success = 1; + } else { + packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); + packet_put_int(listen_port); + packet_put_cstring(host_to_connect); + packet_put_int(port_to_connect); + packet_send(); + packet_write_wait(); + + /* Wait for response from the remote side. */ + type = packet_read(); + switch (type) { + case SSH_SMSG_SUCCESS: + success = 1; + break; + case SSH_SMSG_FAILURE: + break; + default: + /* Unknown packet */ + packet_disconnect("Protocol error for port forward request:" + "received packet type %d.", type); + } + } + if (success) { + permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect); + permitted_opens[num_permitted_opens].port_to_connect = port_to_connect; + permitted_opens[num_permitted_opens].listen_port = listen_port; + num_permitted_opens++; + } + return (success ? 0 : -1); +} + +/* + * Request cancellation of remote forwarding of connection host:port from + * local side. + */ +void +channel_request_rforward_cancel(const char *host, u_short port) +{ + int i; + + if (!compat20) + return; + + for (i = 0; i < num_permitted_opens; i++) { + if (permitted_opens[i].host_to_connect != NULL && + permitted_opens[i].listen_port == port) + break; + } + if (i >= num_permitted_opens) { + debug("%s: requested forward not found", __func__); + return; + } + packet_start(SSH2_MSG_GLOBAL_REQUEST); + packet_put_cstring("cancel-tcpip-forward"); + packet_put_char(0); + packet_put_cstring(host == NULL ? "" : host); + packet_put_int(port); + packet_send(); + + permitted_opens[i].listen_port = 0; + permitted_opens[i].port_to_connect = 0; + xfree(permitted_opens[i].host_to_connect); + permitted_opens[i].host_to_connect = NULL; +} + +/* + * This is called after receiving CHANNEL_FORWARDING_REQUEST. This initates + * listening for the port, and sends back a success reply (or disconnect + * message if there was an error). + */ +int +channel_input_port_forward_request(int is_root, int gateway_ports) +{ + u_short port, host_port; + int success = 0; + char *hostname; + + /* Get arguments from the packet. */ + port = packet_get_int(); + hostname = packet_get_string(NULL); + host_port = packet_get_int(); + +#ifndef HAVE_CYGWIN + /* + * Check that an unprivileged user is not trying to forward a + * privileged port. + */ + if (port < IPPORT_RESERVED && !is_root) + packet_disconnect( + "Requested forwarding of port %d but user is not root.", + port); + if (host_port == 0) + packet_disconnect("Dynamic forwarding denied."); +#endif + + /* Initiate forwarding */ + success = channel_setup_local_fwd_listener(NULL, port, hostname, + host_port, gateway_ports); + + /* Free the argument string. */ + xfree(hostname); + + return (success ? 0 : -1); +} + +/* + * Permits opening to any host/port if permitted_opens[] is empty. This is + * usually called by the server, because the user could connect to any port + * anyway, and the server has no way to know but to trust the client anyway. + */ +void +channel_permit_all_opens(void) +{ + if (num_permitted_opens == 0) + all_opens_permitted = 1; +} + +void +channel_add_permitted_opens(char *host, int port) +{ + if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) + fatal("channel_add_permitted_opens: too many forwards"); + debug("allow port forwarding to host %s port %d", host, port); + + permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host); + permitted_opens[num_permitted_opens].port_to_connect = port; + num_permitted_opens++; + + all_opens_permitted = 0; +} + +int +channel_add_adm_permitted_opens(char *host, int port) +{ + if (num_adm_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) + fatal("channel_add_adm_permitted_opens: too many forwards"); + debug("config allows port forwarding to host %s port %d", host, port); + + permitted_adm_opens[num_adm_permitted_opens].host_to_connect + = xstrdup(host); + permitted_adm_opens[num_adm_permitted_opens].port_to_connect = port; + return ++num_adm_permitted_opens; +} + +void +channel_clear_permitted_opens(void) +{ + int i; + + for (i = 0; i < num_permitted_opens; i++) + if (permitted_opens[i].host_to_connect != NULL) + xfree(permitted_opens[i].host_to_connect); + num_permitted_opens = 0; +} + +void +channel_clear_adm_permitted_opens(void) +{ + int i; + + for (i = 0; i < num_adm_permitted_opens; i++) + if (permitted_adm_opens[i].host_to_connect != NULL) + xfree(permitted_adm_opens[i].host_to_connect); + num_adm_permitted_opens = 0; +} + +/* return socket to remote host, port */ +static 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", port); + if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) { + 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("connect_to: getnameinfo failed"); + continue; + } + sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); + if (sock < 0) { + if (ai->ai_next == NULL) + error("socket: %.100s", strerror(errno)); + else + verbose("socket: %.100s", strerror(errno)); + continue; + } + if (set_nonblock(sock) == -1) + fatal("%s: set_nonblock(%d)", __func__, sock); + if (connect(sock, 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 */ + } + break; /* success */ + + } + freeaddrinfo(aitop); + if (!ai) { + error("connect_to %.100s port %d: failed.", host, port); + return -1; + } + /* success */ + set_nodelay(sock); + return sock; +} + +int +channel_connect_by_listen_address(u_short listen_port) +{ + int i; + + for (i = 0; i < num_permitted_opens; i++) + if (permitted_opens[i].host_to_connect != NULL && + permitted_opens[i].listen_port == listen_port) + return connect_to( + permitted_opens[i].host_to_connect, + permitted_opens[i].port_to_connect); + error("WARNING: Server requests forwarding for unknown listen_port %d", + listen_port); + return -1; +} + +/* Check if connecting to that port is permitted and connect. */ +int +channel_connect_to(const char *host, u_short port) +{ + int i, permit, permit_adm = 1; + + permit = all_opens_permitted; + if (!permit) { + for (i = 0; i < num_permitted_opens; i++) + if (permitted_opens[i].host_to_connect != NULL && + permitted_opens[i].port_to_connect == port && + strcmp(permitted_opens[i].host_to_connect, host) == 0) + permit = 1; + } + + if (num_adm_permitted_opens > 0) { + permit_adm = 0; + for (i = 0; i < num_adm_permitted_opens; i++) + if (permitted_adm_opens[i].host_to_connect != NULL && + permitted_adm_opens[i].port_to_connect == port && + strcmp(permitted_adm_opens[i].host_to_connect, host) + == 0) + permit_adm = 1; + } + + if (!permit || !permit_adm) { + logit("Received request to connect to host %.100s port %d, " + "but the request was denied.", host, port); + return -1; + } + return connect_to(host, port); +} + +void +channel_send_window_changes(void) +{ + u_int i; + struct winsize ws; + + for (i = 0; i < channels_alloc; i++) { + if (channels[i] == NULL || !channels[i]->client_tty || + channels[i]->type != SSH_CHANNEL_OPEN) + continue; + if (ioctl(channels[i]->rfd, TIOCGWINSZ, &ws) < 0) + continue; + channel_request_start(i, "window-change", 0); + packet_put_int((u_int)ws.ws_col); + packet_put_int((u_int)ws.ws_row); + packet_put_int((u_int)ws.ws_xpixel); + packet_put_int((u_int)ws.ws_ypixel); + packet_send(); + } +} + +/* -- X11 forwarding */ + +/* + * Creates an internet domain socket for listening for X11 connections. + * Returns 0 and a suitable display number for the DISPLAY variable + * stored in display_numberp , or -1 if an error occurs. + */ +int +x11_create_display_inet(int x11_display_offset, int x11_use_localhost, + int single_connection, u_int *display_numberp, int **chanids) +{ + Channel *nc = NULL; + int display_number, sock; + u_short port; + struct addrinfo hints, *ai, *aitop; + char strport[NI_MAXSERV]; + int gaierr, n, num_socks = 0, socks[NUM_SOCKS]; + + if (chanids == NULL) + return -1; + + for (display_number = x11_display_offset; + display_number < MAX_DISPLAYS; + display_number++) { + port = 6000 + display_number; + memset(&hints, 0, sizeof(hints)); + hints.ai_family = IPv4or6; + hints.ai_flags = x11_use_localhost ? 0: AI_PASSIVE; + hints.ai_socktype = SOCK_STREAM; + snprintf(strport, sizeof strport, "%d", port); + if ((gaierr = getaddrinfo(NULL, strport, &hints, &aitop)) != 0) { + error("getaddrinfo: %.100s", gai_strerror(gaierr)); + return -1; + } + for (ai = aitop; ai; ai = ai->ai_next) { + if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) + continue; + sock = socket(ai->ai_family, ai->ai_socktype, + ai->ai_protocol); + if (sock < 0) { + if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) { + error("socket: %.100s", strerror(errno)); + freeaddrinfo(aitop); + return -1; + } else { + debug("x11_create_display_inet: Socket family %d not supported", + ai->ai_family); + continue; + } + } +#ifdef IPV6_V6ONLY + if (ai->ai_family == AF_INET6) { + int on = 1; + if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) < 0) + error("setsockopt IPV6_V6ONLY: %.100s", strerror(errno)); + } +#endif + channel_set_reuseaddr(sock); + if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { + debug2("bind port %d: %.100s", port, strerror(errno)); + close(sock); + + if (ai->ai_next) + continue; + + for (n = 0; n < num_socks; n++) { + close(socks[n]); + } + num_socks = 0; + break; + } + socks[num_socks++] = sock; +#ifndef DONT_TRY_OTHER_AF + if (num_socks == NUM_SOCKS) + break; +#else + if (x11_use_localhost) { + if (num_socks == NUM_SOCKS) + break; + } else { + break; + } +#endif + } + freeaddrinfo(aitop); + if (num_socks > 0) + break; + } + if (display_number >= MAX_DISPLAYS) { + error("Failed to allocate internet-domain X11 display socket."); + return -1; + } + /* Start listening for connections on the socket. */ + for (n = 0; n < num_socks; n++) { + sock = socks[n]; + if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { + error("listen: %.100s", strerror(errno)); + close(sock); + return -1; + } + } + + /* Allocate a channel for each socket. */ + *chanids = xcalloc(num_socks + 1, sizeof(**chanids)); + for (n = 0; n < num_socks; n++) { + sock = socks[n]; + nc = channel_new("x11 listener", + SSH_CHANNEL_X11_LISTENER, sock, sock, -1, + CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, + 0, "X11 inet listener", 1); + nc->single_connection = single_connection; + (*chanids)[n] = nc->self; + } + (*chanids)[n] = -1; + + /* Return the display number for the DISPLAY environment variable. */ + *display_numberp = display_number; + return (0); +} + +static int +connect_local_xsocket(u_int dnr) +{ + int sock; + struct sockaddr_un addr; + + sock = socket(AF_UNIX, SOCK_STREAM, 0); + if (sock < 0) + error("socket: %.100s", strerror(errno)); + memset(&addr, 0, sizeof(addr)); + addr.sun_family = AF_UNIX; + snprintf(addr.sun_path, sizeof addr.sun_path, _PATH_UNIX_X, dnr); + if (connect(sock, (struct sockaddr *)&addr, sizeof(addr)) == 0) + return sock; + close(sock); + error("connect %.100s: %.100s", addr.sun_path, strerror(errno)); + return -1; +} + +int +x11_connect_display(void) +{ + u_int display_number; + const char *display; + char buf[1024], *cp; + struct addrinfo hints, *ai, *aitop; + char strport[NI_MAXSERV]; + int gaierr, sock = 0; + + /* Try to open a socket for the local X server. */ + display = getenv("DISPLAY"); + if (!display) { + error("DISPLAY not set."); + return -1; + } + /* + * Now we decode the value of the DISPLAY variable and make a + * connection to the real X server. + */ + + /* + * Check if it is a unix domain socket. Unix domain displays are in + * one of the following formats: unix:d[.s], :d[.s], ::d[.s] + */ + if (strncmp(display, "unix:", 5) == 0 || + display[0] == ':') { + /* Connect to the unix domain socket. */ + if (sscanf(strrchr(display, ':') + 1, "%u", &display_number) != 1) { + error("Could not parse display number from DISPLAY: %.100s", + display); + return -1; + } + /* Create a socket. */ + sock = connect_local_xsocket(display_number); + if (sock < 0) + return -1; + + /* OK, we now have a connection to the display. */ + return sock; + } + /* + * Connect to an inet socket. The DISPLAY value is supposedly + * hostname:d[.s], where hostname may also be numeric IP address. + */ + strlcpy(buf, display, sizeof(buf)); + cp = strchr(buf, ':'); + if (!cp) { + error("Could not find ':' in DISPLAY: %.100s", display); + return -1; + } + *cp = 0; + /* buf now contains the host name. But first we parse the display number. */ + if (sscanf(cp + 1, "%u", &display_number) != 1) { + error("Could not parse display number from DISPLAY: %.100s", + display); + return -1; + } + + /* Look up the host address */ + memset(&hints, 0, sizeof(hints)); + hints.ai_family = IPv4or6; + hints.ai_socktype = SOCK_STREAM; + snprintf(strport, sizeof strport, "%u", 6000 + display_number); + if ((gaierr = getaddrinfo(buf, strport, &hints, &aitop)) != 0) { + error("%.100s: unknown host. (%s)", buf, gai_strerror(gaierr)); + return -1; + } + for (ai = aitop; ai; ai = ai->ai_next) { + /* Create a socket. */ + sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); + if (sock < 0) { + debug2("socket: %.100s", strerror(errno)); + continue; + } + /* Connect it to the display. */ + if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { + debug2("connect %.100s port %u: %.100s", buf, + 6000 + display_number, strerror(errno)); + close(sock); + continue; + } + /* Success */ + break; + } + freeaddrinfo(aitop); + if (!ai) { + error("connect %.100s port %u: %.100s", buf, 6000 + display_number, + strerror(errno)); + return -1; + } + set_nodelay(sock); + return sock; +} + +/* + * This is called when SSH_SMSG_X11_OPEN is received. The packet contains + * the remote channel number. We should do whatever we want, and respond + * with either SSH_MSG_OPEN_CONFIRMATION or SSH_MSG_OPEN_FAILURE. + */ + +/* ARGSUSED */ +void +x11_input_open(int type, u_int32_t seq, void *ctxt) +{ + Channel *c = NULL; + int remote_id, sock = 0; + char *remote_host; + + debug("Received X11 open request."); + + remote_id = packet_get_int(); + + if (packet_get_protocol_flags() & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) { + remote_host = packet_get_string(NULL); + } else { + remote_host = xstrdup("unknown (remote did not supply name)"); + } + packet_check_eom(); + + /* Obtain a connection to the real X display. */ + sock = x11_connect_display(); + if (sock != -1) { + /* Allocate a channel for this connection. */ + c = channel_new("connected x11 socket", + SSH_CHANNEL_X11_OPEN, sock, sock, -1, 0, 0, 0, + remote_host, 1); + c->remote_id = remote_id; + c->force_drain = 1; + } + xfree(remote_host); + if (c == NULL) { + /* Send refusal to the remote host. */ + packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); + packet_put_int(remote_id); + } else { + /* Send a confirmation to the remote host. */ + packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); + packet_put_int(remote_id); + packet_put_int(c->self); + } + packet_send(); +} + +/* dummy protocol handler that denies SSH-1 requests (agent/x11) */ +/* ARGSUSED */ +void +deny_input_open(int type, u_int32_t seq, void *ctxt) +{ + int rchan = packet_get_int(); + + switch (type) { + case SSH_SMSG_AGENT_OPEN: + error("Warning: ssh server tried agent forwarding."); + break; + case SSH_SMSG_X11_OPEN: + error("Warning: ssh server tried X11 forwarding."); + break; + default: + error("deny_input_open: type %d", type); + break; + } + error("Warning: this is probably a break-in attempt by a malicious server."); + packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); + packet_put_int(rchan); + packet_send(); +} + +/* + * Requests forwarding of X11 connections, generates fake authentication + * data, and enables authentication spoofing. + * This should be called in the client only. + */ +void +x11_request_forwarding_with_spoofing(int client_session_id, const char *disp, + const char *proto, const char *data) +{ + u_int data_len = (u_int) strlen(data) / 2; + u_int i, value; + char *new_data; + int screen_number; + const char *cp; + u_int32_t rnd = 0; + + if (x11_saved_display == NULL) + x11_saved_display = xstrdup(disp); + else if (strcmp(disp, x11_saved_display) != 0) { + error("x11_request_forwarding_with_spoofing: different " + "$DISPLAY already forwarded"); + return; + } + + cp = strchr(disp, ':'); + if (cp) + cp = strchr(cp, '.'); + if (cp) + screen_number = (u_int)strtonum(cp + 1, 0, 400, NULL); + else + screen_number = 0; + + if (x11_saved_proto == NULL) { + /* Save protocol name. */ + x11_saved_proto = xstrdup(proto); + /* + * Extract real authentication data and generate fake data + * of the same length. + */ + x11_saved_data = xmalloc(data_len); + x11_fake_data = xmalloc(data_len); + for (i = 0; i < data_len; i++) { + if (sscanf(data + 2 * i, "%2x", &value) != 1) + fatal("x11_request_forwarding: bad " + "authentication data: %.100s", data); + if (i % 4 == 0) + rnd = arc4random(); + x11_saved_data[i] = value; + x11_fake_data[i] = rnd & 0xff; + rnd >>= 8; + } + x11_saved_data_len = data_len; + x11_fake_data_len = data_len; + } + + /* Convert the fake data into hex. */ + new_data = tohex(x11_fake_data, data_len); + + /* Send the request packet. */ + if (compat20) { + channel_request_start(client_session_id, "x11-req", 0); + packet_put_char(0); /* XXX bool single connection */ + } else { + packet_start(SSH_CMSG_X11_REQUEST_FORWARDING); + } + packet_put_cstring(proto); + packet_put_cstring(new_data); + packet_put_int(screen_number); + packet_send(); + packet_write_wait(); + xfree(new_data); +} + + +/* -- agent forwarding */ + +/* Sends a message to the server to request authentication fd forwarding. */ + +void +auth_request_forwarding(void) +{ + packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); + packet_send(); + packet_write_wait(); +} |