diff options
Diffstat (limited to 'crypto/openssh/channels.c')
| -rw-r--r-- | crypto/openssh/channels.c | 2277 |
1 files changed, 0 insertions, 2277 deletions
diff --git a/crypto/openssh/channels.c b/crypto/openssh/channels.c deleted file mode 100644 index 5bf1e5b7aea7a..0000000000000 --- a/crypto/openssh/channels.c +++ /dev/null @@ -1,2277 +0,0 @@ -/* - * - * channels.c - * - * Author: Tatu Ylonen <ylo@cs.hut.fi> - * - * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, 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. - * - * SSH2 support added by Markus Friedl. - */ - -#include "includes.h" -RCSID("$Id: channels.c,v 1.57 2000/05/08 17:42:24 markus Exp $"); - -#include "ssh.h" -#include "packet.h" -#include "xmalloc.h" -#include "buffer.h" -#include "authfd.h" -#include "uidswap.h" -#include "readconf.h" -#include "servconf.h" - -#include "channels.h" -#include "nchan.h" -#include "compat.h" - -#include "ssh2.h" - -/* Maximum number of fake X11 displays to try. */ -#define MAX_DISPLAYS 1000 - -/* Max len of agent socket */ -#define MAX_SOCKET_NAME 100 - -/* default window/packet sizes for tcp/x11-fwd-channel */ -#define CHAN_TCP_WINDOW_DEFAULT (8*1024) -#define CHAN_TCP_PACKET_DEFAULT (CHAN_TCP_WINDOW_DEFAULT/2) -#define CHAN_X11_WINDOW_DEFAULT (4*1024) -#define CHAN_X11_PACKET_DEFAULT (CHAN_X11_WINDOW_DEFAULT/2) - -/* - * 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 are marked with type - * SSH_CHANNEL_FREE. - */ -static int channels_alloc = 0; - -/* - * Maximum file descriptor value used in any of the channels. This is - * updated in channel_allocate. - */ -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; - -/* 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; - -/* - * 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. */ -static ForwardPermission permitted_opens[SSH_MAX_FORWARDS_PER_DIRECTION]; -/* Number of permitted host/port pairs in the array. */ -static int num_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; - -/* 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. */ - -void -channel_set_options(int hostname_in_open) -{ - have_hostname_in_open = hostname_in_open; -} - -/* - * 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. - */ - -void -channel_permit_all_opens() -{ - all_opens_permitted = 1; -} - -/* lookup channel by id */ - -Channel * -channel_lookup(int id) -{ - Channel *c; - if (id < 0 && id > channels_alloc) { - log("channel_lookup: %d: bad id", id); - return NULL; - } - c = &channels[id]; - if (c->type == SSH_CHANNEL_FREE) { - log("channel_lookup: %d: bad id: channel free", id); - return NULL; - } - return c; -} - -void -set_nonblock(int fd) -{ - int val; - val = fcntl(fd, F_GETFL, 0); - if (val < 0) { - error("fcntl(%d, F_GETFL, 0): %s", fd, strerror(errno)); - return; - } - if (val & O_NONBLOCK) - return; - debug("fd %d setting O_NONBLOCK", fd); - val |= O_NONBLOCK; - if (fcntl(fd, F_SETFL, val) == -1) - error("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd, strerror(errno)); -} - -/* - * 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_register_fds(Channel *c, int rfd, int wfd, int efd, int extusage) -{ - /* Update the maximum file descriptor value. */ - if (rfd > channel_max_fd_value) - channel_max_fd_value = rfd; - if (wfd > channel_max_fd_value) - channel_max_fd_value = wfd; - if (efd > channel_max_fd_value) - channel_max_fd_value = 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; - 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. - */ - -int -channel_new(char *ctype, int type, int rfd, int wfd, int efd, - int window, int maxpack, int extusage, char *remote_name) -{ - int i, found; - Channel *c; - - /* Do initial allocation if this is the first call. */ - if (channels_alloc == 0) { - chan_init(); - channels_alloc = 10; - channels = xmalloc(channels_alloc * sizeof(Channel)); - for (i = 0; i < channels_alloc; i++) - channels[i].type = SSH_CHANNEL_FREE; - /* - * Kludge: arrange a call to channel_stop_listening if we - * terminate with fatal(). - */ - fatal_add_cleanup((void (*) (void *)) channel_stop_listening, 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].type == SSH_CHANNEL_FREE) { - /* Found a free slot. */ - found = i; - break; - } - if (found == -1) { - /* 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)); - for (i = found; i < channels_alloc; i++) - channels[i].type = SSH_CHANNEL_FREE; - } - /* Initialize and return new channel number. */ - c = &channels[found]; - buffer_init(&c->input); - buffer_init(&c->output); - buffer_init(&c->extended); - chan_init_iostates(c); - channel_register_fds(c, rfd, wfd, efd, extusage); - 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 = 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; - debug("channel %d: new [%s]", found, remote_name); - return found; -} -/* old interface XXX */ -int -channel_allocate(int type, int sock, char *remote_name) -{ - return channel_new("", type, sock, sock, -1, 0, 0, 0, remote_name); -} - - -/* Close all channel fd/socket. */ - -void -channel_close_fds(Channel *c) -{ - 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(int id) -{ - Channel *c = channel_lookup(id); - if (c == NULL) - packet_disconnect("channel free: bad local channel %d", id); - debug("channel_free: channel %d: status: %s", id, channel_open_message()); - if (c->dettach_user != NULL) { - debug("channel_free: channel %d: dettaching channel user", id); - 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); - c->type = SSH_CHANNEL_FREE; - if (c->remote_name) { - xfree(c->remote_name); - c->remote_name = NULL; - } -} - -/* - * '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]; - -void -channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset) -{ - FD_SET(c->sock, readset); -} - -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("Closing channel %d after input drain.", c->self); - } -} - -void -channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset) -{ - if (buffer_len(&c->output) == 0) - channel_free(c->self); - 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. - */ -int -x11_open_helper(Channel *c) -{ - unsigned char *ucp; - unsigned int proto_len, data_len; - - /* Check if the fixed size part of the packet is in buffer. */ - if (buffer_len(&c->output) < 12) - return 0; - - /* Parse the lengths of variable-length fields. */ - ucp = (unsigned char *) buffer_ptr(&c->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]); - return -1; - } - - /* Check if the whole packet is in buffer. */ - if (buffer_len(&c->output) < - 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); - 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.\r\n"); - 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); - 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); - } -} - -/* This is our fake X11 server socket. */ -void -channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset) -{ - struct sockaddr addr; - int newsock, newch; - socklen_t addrlen; - char buf[16384], *remote_hostname; - 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_hostname = get_remote_hostname(newsock); - remote_port = get_peer_port(newsock); - snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", - remote_hostname, remote_port); - - newch = channel_new("x11", - SSH_CHANNEL_OPENING, newsock, newsock, -1, - c->local_window_max, c->local_maxpacket, - 0, xstrdup(buf)); - if (compat20) { - packet_start(SSH2_MSG_CHANNEL_OPEN); - packet_put_cstring("x11"); - packet_put_int(newch); - packet_put_int(c->local_window_max); - packet_put_int(c->local_maxpacket); - /* originator host and port */ - packet_put_cstring(remote_hostname); - 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(newch); - if (have_hostname_in_open) - packet_put_string(buf, strlen(buf)); - packet_send(); - } - xfree(remote_hostname); - } -} - -/* - * 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) -{ - struct sockaddr addr; - int newsock, newch; - socklen_t addrlen; - char buf[1024], *remote_hostname; - int remote_port; - - 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); - addrlen = sizeof(addr); - newsock = accept(c->sock, &addr, &addrlen); - if (newsock < 0) { - error("accept: %.100s", strerror(errno)); - return; - } - remote_hostname = get_remote_hostname(newsock); - remote_port = get_peer_port(newsock); - snprintf(buf, sizeof buf, - "listen port %d for %.100s port %d, " - "connect from %.200s port %d", - c->listening_port, c->path, c->host_port, - remote_hostname, remote_port); - newch = channel_new("direct-tcpip", - SSH_CHANNEL_OPENING, newsock, newsock, -1, - c->local_window_max, c->local_maxpacket, - 0, xstrdup(buf)); - if (compat20) { - packet_start(SSH2_MSG_CHANNEL_OPEN); - packet_put_cstring("direct-tcpip"); - packet_put_int(newch); - packet_put_int(c->local_window_max); - packet_put_int(c->local_maxpacket); - /* target host and port */ - packet_put_string(c->path, strlen(c->path)); - packet_put_int(c->host_port); - /* originator host and port */ - packet_put_cstring(remote_hostname); - packet_put_int(remote_port); - packet_send(); - } else { - packet_start(SSH_MSG_PORT_OPEN); - packet_put_int(newch); - packet_put_string(c->path, strlen(c->path)); - packet_put_int(c->host_port); - if (have_hostname_in_open) { - packet_put_string(buf, strlen(buf)); - } - packet_send(); - } - xfree(remote_hostname); - } -} - -/* - * This is the authentication agent socket listening for connections from - * clients. - */ -void -channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset) -{ - struct sockaddr addr; - int newsock, newch; - 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; - } - newch = channel_allocate(SSH_CHANNEL_OPENING, newsock, - xstrdup("accepted auth socket")); - packet_start(SSH_SMSG_AGENT_OPEN); - packet_put_int(newch); - 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 (compat13) { - buffer_consume(&c->output, buffer_len(&c->output)); - c->type = SSH_CHANNEL_INPUT_DRAINING; - debug("Channel %d status set to input draining.", c->self); - } else { - chan_read_failed(c); - } - return -1; - } - buffer_append(&c->input, buf, len); - } - return 1; -} -int -channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset) -{ - 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 (compat13) { - buffer_consume(&c->output, buffer_len(&c->output)); - debug("Channel %d status set to input draining.", c->self); - c->type = SSH_CHANNEL_INPUT_DRAINING; - } else { - chan_write_failed(c); - } - return -1; - } - 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)); - debug("channel %d: written %d to efd %d", - c->self, len, c->efd); - if (len > 0) { - 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)); - debug("channel %d: read %d from efd %d", - c->self, len, c->efd); - if (len == 0) { - debug("channel %d: closing efd %d", - c->self, c->efd); - close(c->efd); - c->efd = -1; - } else if (len > 0) - buffer_append(&c->extended, buf, len); - } - } - return 1; -} -int -channel_check_window(Channel *c, fd_set * readset, fd_set * writeset) -{ - if (!(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(); - debug("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); -} - -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); - channel_check_window(c, readset, writeset); -} - -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_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_X11_LISTENER] = &channel_pre_listener; - - channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2; - channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; - channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; -} - -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_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; -} - -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_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; -} - -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->type == SSH_CHANNEL_FREE) - continue; - if (ftab[c->type] == NULL) - continue; - (*ftab[c->type])(c, readset, writeset); - chan_delete_if_full_closed(c); - } -} - -void -channel_prepare_select(fd_set * readset, fd_set * writeset) -{ - channel_handler(channel_pre, readset, writeset); -} - -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, send some of it now. */ - -void -channel_output_poll() -{ - int len, i; - Channel *c; - - for (i = 0; i < channels_alloc; i++) { - c = &channels[i]; - - /* 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 (c->istate != CHAN_INPUT_OPEN && - c->istate != CHAN_INPUT_WAIT_DRAIN) - continue; - } - if (compat20 && - (c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD))) { - debug("channel: %d: no data after CLOSE", c->self); - continue; - } - - /* Get the amount of buffered data for this channel. */ - len = buffer_len(&c->input); - if (len > 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; - debug("channel %d: send data len %d", c->self, 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) { - 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; - } - } -} - -/* - * 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. - */ - -void -channel_input_data(int type, int plen) -{ - int id; - char *data; - unsigned 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) -{ - int id; - int tcode; - char *data; - unsigned 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 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; - } - debug("channel %d: rcvd ext data %d", c->self, data_len); - c->local_window -= data_len; - buffer_append(&c->extended, data, data_len); - xfree(data); -} - - -/* - * 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() -{ - unsigned int i; - Channel *c; - - for (i = 0; i < channels_alloc; i++) { - c = &channels[i]; - if (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; - } - } - } - return 1; -} - -void -channel_input_ieof(int type, int plen) -{ - 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) -{ - 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(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_consume(&c->input, buffer_len(&c->input)); - c->type = SSH_CHANNEL_OUTPUT_DRAINING; - } -} - -/* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ -void -channel_input_oclose(int type, int plen) -{ - 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); -} - -void -channel_input_close_confirmation(int type, int plen) -{ - 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->self); -} - -void -channel_input_open_confirmation(int type, int plen) -{ - int id, remote_id; - Channel *c; - - if (!compat20) - packet_integrity_check(plen, 4 + 4, type); - - 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(); - packet_done(); - if (c->cb_fn != NULL && c->cb_event == type) { - debug("callback start"); - c->cb_fn(c->self, c->cb_arg); - debug("callback done"); - } - debug("channel %d: open confirm rwindow %d rmax %d", c->self, - c->remote_window, c->remote_maxpacket); - } -} - -void -channel_input_open_failure(int type, int plen) -{ - int id; - Channel *c; - - 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) { - int reason = packet_get_int(); - char *msg = packet_get_string(NULL); - char *lang = packet_get_string(NULL); - log("channel_open_failure: %d: reason %d: %s", id, reason, msg); - packet_done(); - xfree(msg); - xfree(lang); - } - /* Free the channel. This will also close the socket. */ - channel_free(id); -} - -void -channel_input_channel_request(int type, int plen) -{ - 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) { - debug("callback start"); - c->cb_fn(c->self, c->cb_arg); - debug("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); - } -} - -void -channel_input_window_adjust(int type, int plen) -{ - 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(); - debug("channel %d: rcvd adjust %d", id, adjust); - c->remote_window += adjust; -} - -/* - * Stops listening for channels, and removes any unix domain sockets that we - * might have. - */ - -void -channel_stop_listening() -{ - 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; - } - } -} - -/* - * Closes the sockets/fds of all channels. This is used to close extra file - * descriptors after a fork. - */ - -void -channel_close_all() -{ - int i; - for (i = 0; i < channels_alloc; i++) - if (channels[i].type != SSH_CHANNEL_FREE) - channel_close_fds(&channels[i]); -} - -/* Returns the maximum file descriptor number used by the channels. */ - -int -channel_max_fd() -{ - return channel_max_fd_value; -} - -/* Returns true if any channel is still open. */ - -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_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", channels[i].type); - /* NOTREACHED */ - } - return 0; -} - -/* - * 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_LARVAL: - 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 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; -} - -/* - * Initiate forwarding of connections to local port "port" through the secure - * channel to host:port from remote side. - */ - -void -channel_request_local_forwarding(u_short port, const char *host, - u_short host_port, int gateway_ports) -{ - int success, ch, sock, on = 1; - struct addrinfo hints, *ai, *aitop; - char ntop[NI_MAXHOST], strport[NI_MAXSERV]; - struct linger linger; - - if (strlen(host) > sizeof(channels[0].path) - 1) - packet_disconnect("Forward host name too long."); - - /* - * 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 = gateway_ports ? AI_PASSIVE : 0; - hints.ai_socktype = SOCK_STREAM; - snprintf(strport, sizeof strport, "%d", 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"); - continue; - } - /* Create a port to listen for the host. */ - sock = socket(ai->ai_family, SOCK_STREAM, 0); - if (sock < 0) { - /* this is no error since kernel may not support ipv6 */ - verbose("socket: %.100s", strerror(errno)); - continue; - } - /* - * Set socket options. We would like the socket to disappear - * as soon as it has been closed for whatever reason. - */ - setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); - linger.l_onoff = 1; - linger.l_linger = 5; - setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger)); - 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 */ - verbose("bind: %.100s", strerror(errno)); - close(sock); - continue; - } - /* Start listening for connections on the socket. */ - if (listen(sock, 5) < 0) { - error("listen: %.100s", strerror(errno)); - close(sock); - continue; - } - /* Allocate a channel number for the socket. */ - ch = channel_new( - "port listener", SSH_CHANNEL_PORT_LISTENER, - sock, sock, -1, - CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, - 0, xstrdup("port listener")); - strlcpy(channels[ch].path, host, sizeof(channels[ch].path)); - channels[ch].host_port = host_port; - channels[ch].listening_port = port; - success = 1; - } - if (success == 0) - packet_disconnect("cannot listen port: %d", port); - freeaddrinfo(aitop); -} - -/* - * Initiate forwarding of connections to port "port" on remote host through - * the secure channel to host:port from local side. - */ - -void -channel_request_remote_forwarding(u_short listen_port, const char *host_to_connect, - u_short port_to_connect) -{ - int payload_len; - /* 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_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++; - - /* Send the forward request to the remote side. */ - 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); - } 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); - } -} - -/* - * 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). This never returns if there was an error. - */ - -void -channel_input_port_forward_request(int is_root, int gateway_ports) -{ - u_short port, host_port; - char *hostname; - - /* Get arguments from the packet. */ - port = packet_get_int(); - hostname = packet_get_string(NULL); - host_port = packet_get_int(); - - /* - * 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); - /* - * Initiate forwarding, - */ - channel_request_local_forwarding(port, hostname, host_port, gateway_ports); - - /* Free the argument string. */ - xfree(hostname); -} - -/* XXX move to aux.c */ -int -channel_connect_to(const char *host, u_short host_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); - if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) { - error("%.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_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, - strerror(errno)); - close(sock); - continue; /* fail -- try next */ - } - break; /* success */ - - } - freeaddrinfo(aitop); - if (!ai) { - error("connect %.100s port %d: failed.", host, host_port); - return -1; - } - /* success */ - return sock; -} -/* - * 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. - */ - -void -channel_input_port_open(int type, int plen) -{ - u_short host_port; - char *host, *originator_string; - int remote_channel, sock = -1, newch, i, denied; - unsigned int host_len, originator_len; - - /* Get remote channel number. */ - remote_channel = packet_get_int(); - - /* Get host name to connect to. */ - host = packet_get_string(&host_len); - - /* Get port to connect to. */ - host_port = packet_get_int(); - - /* 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 */ - } - - packet_integrity_check(plen, - 4 + 4 + host_len + 4 + originator_len, SSH_MSG_PORT_OPEN); - - /* Check if opening that port is permitted. */ - denied = 0; - if (!all_opens_permitted) { - /* Go trough all permitted ports. */ - for (i = 0; i < num_permitted_opens; i++) - if (permitted_opens[i].port_to_connect == host_port && - strcmp(permitted_opens[i].host_to_connect, 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); - denied = 1; - } - } - sock = denied ? -1 : channel_connect_to(host, host_port); - if (sock > 0) { - /* Allocate a channel for this connection. */ - newch = channel_allocate(SSH_CHANNEL_OPEN, sock, originator_string); - channels[newch].remote_id = remote_channel; - - packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); - packet_put_int(remote_channel); - packet_put_int(newch); - packet_send(); - } else { - packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); - packet_put_int(remote_channel); - packet_send(); - } - xfree(host); -} - -/* - * 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) -{ - 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]; - char display[512]; - char hostname[MAXHOSTNAMELEN]; - - 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 = AI_PASSIVE; /* XXX loopback only ? */ - 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 NULL; - } - 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, SOCK_STREAM, 0); - if (sock < 0) { - error("socket: %.100s", strerror(errno)); - return NULL; - } - if (bind(sock, ai->ai_addr, ai->ai_addrlen) < 0) { - debug("bind port %d: %.100s", port, strerror(errno)); - shutdown(sock, SHUT_RDWR); - close(sock); - for (n = 0; n < num_socks; n++) { - shutdown(socks[n], SHUT_RDWR); - close(socks[n]); - } - num_socks = 0; - break; - } - socks[num_socks++] = sock; - if (num_socks == NUM_SOCKS) - break; - } - if (num_socks > 0) - break; - } - if (display_number >= MAX_DISPLAYS) { - error("Failed to allocate internet-domain X11 display socket."); - return NULL; - } - /* Start listening for connections on the socket. */ - for (n = 0; n < num_socks; n++) { - sock = socks[n]; - if (listen(sock, 5) < 0) { - error("listen: %.100s", strerror(errno)); - shutdown(sock, SHUT_RDWR); - close(sock); - return NULL; - } - } - - /* Set up a suitable value for the DISPLAY variable. */ - if (gethostname(hostname, sizeof(hostname)) < 0) - fatal("gethostname: %.100s", strerror(errno)); - snprintf(display, sizeof display, "%.400s:%d.%d", hostname, - display_number, screen_number); - - /* Allocate a channel for each socket. */ - for (n = 0; n < num_socks; n++) { - sock = socks[n]; - (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")); - } - - /* Return a suitable value for the DISPLAY environment variable. */ - return xstrdup(display); -} - -#ifndef X_UNIX_PATH -#define X_UNIX_PATH "/tmp/.X11-unix/X" -#endif - -static -int -connect_local_xsocket(unsigned int dnr) -{ - static const char *const x_sockets[] = { - X_UNIX_PATH "%u", - "/var/X/.X11-unix/X" "%u", - "/usr/spool/sockets/X11/" "%u", - NULL - }; - int sock; - struct sockaddr_un addr; - const char *const * path; - - for (path = x_sockets; *path; ++path) { - 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, 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) -{ - int display_number, sock = 0; - const char *display; - char buf[1024], *cp; - struct addrinfo hints, *ai, *aitop; - char strport[NI_MAXSERV]; - int gaierr; - - /* 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, "%d", &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. - */ - strncpy(buf, display, sizeof(buf)); - buf[sizeof(buf) - 1] = 0; - 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, "%d", &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, "%d", 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, 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; - } - /* Success */ - break; - } - freeaddrinfo(aitop); - if (!ai) { - error("connect %.100s port %d: %.100s", buf, 6000 + display_number, - strerror(errno)); - return -1; - } - 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. - */ - -void -x11_input_open(int type, int plen) -{ - int remote_channel, sock = 0, newch; - char *remote_host; - unsigned int remote_len; - - /* 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(plen, 4 + remote_len, SSH_SMSG_X11_OPEN); - - /* Obtain a connection to the real X display. */ - sock = x11_connect_display(); - if (sock == -1) { - /* Send refusal to the remote host. */ - packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); - packet_put_int(remote_channel); - packet_send(); - } else { - /* Allocate a channel for this connection. */ - newch = channel_allocate( - (x11_saved_proto == NULL) ? - SSH_CHANNEL_OPEN : SSH_CHANNEL_X11_OPEN, - sock, remote_host); - 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(); - } -} - -/* - * Requests forwarding of X11 connections, generates fake authentication - * data, and enables authentication spoofing. - */ - -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; - char *new_data; - int screen_number; - const char *cp; - u_int32_t rand = 0; - - cp = getenv("DISPLAY"); - if (cp) - cp = strchr(cp, ':'); - if (cp) - cp = strchr(cp, '.'); - if (cp) - screen_number = atoi(cp + 1); - else - screen_number = 0; - - /* 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) - rand = arc4random(); - x11_saved_data[i] = value; - x11_fake_data[i] = rand & 0xff; - rand >>= 8; - } - x11_saved_data_len = data_len; - x11_fake_data_len = data_len; - - /* Convert the fake data into hex. */ - new_data = xmalloc(2 * data_len + 1); - for (i = 0; i < data_len; i++) - sprintf(new_data + 2 * i, "%02x", (unsigned char) x11_fake_data[i]); - - /* 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); -} - -/* Sends a message to the server to request authentication fd forwarding. */ - -void -auth_request_forwarding() -{ - packet_start(SSH_CMSG_AGENT_REQUEST_FORWARDING); - packet_send(); - packet_write_wait(); -} - -/* - * Returns the name of the forwarded authentication socket. Returns NULL if - * there is no forwarded authentication socket. The returned value points to - * a static buffer. - */ - -char * -auth_get_socket_name() -{ - return channel_forwarded_auth_socket_name; -} - -/* removes the agent forwarding socket */ - -void -cleanup_socket(void) -{ - remove(channel_forwarded_auth_socket_name); - rmdir(channel_forwarded_auth_socket_dir); -} - -/* - * This if called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server. - * This starts forwarding authentication requests. - */ - -void -auth_input_request_forwarding(struct passwd * pw) -{ - int sock, newch; - struct sockaddr_un sunaddr; - - if (auth_get_socket_name() != NULL) - fatal("Protocol error: authentication forwarding requested twice."); - - /* Temporarily drop privileged uid for mkdir/bind. */ - temporarily_use_uid(pw->pw_uid); - - /* 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); - - /* 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)); - } - /* Create the socket. */ - sock = socket(AF_UNIX, SOCK_STREAM, 0); - if (sock < 0) - packet_disconnect("socket: %.100s", strerror(errno)); - - /* Bind it to the name. */ - memset(&sunaddr, 0, sizeof(sunaddr)); - sunaddr.sun_family = AF_UNIX; - strncpy(sunaddr.sun_path, channel_forwarded_auth_socket_name, - sizeof(sunaddr.sun_path)); - - if (bind(sock, (struct sockaddr *) & sunaddr, sizeof(sunaddr)) < 0) - packet_disconnect("bind: %.100s", strerror(errno)); - - /* Restore the privileged uid. */ - restore_uid(); - - /* Start listening on the socket. */ - if (listen(sock, 5) < 0) - 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)); -} - -/* This is called to process an SSH_SMSG_AGENT_OPEN message. */ - -void -auth_input_open_request(int type, int plen) -{ - int remch, sock, newch; - char *dummyname; - - packet_integrity_check(plen, 4, type); - - /* Read the remote channel number from the message. */ - remch = packet_get_int(); - - /* - * Get a connection to the local authentication agent (this may again - * get forwarded). - */ - sock = ssh_get_authentication_socket(); - - /* - * If we could not connect the agent, send an error message back to - * the server. This should never happen unless the agent dies, - * because authentication forwarding is only enabled if we have an - * agent. - */ - if (sock < 0) { - packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); - packet_put_int(remch); - packet_send(); - return; - } - 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(); -} - -void -channel_start_open(int id) -{ - Channel *c = channel_lookup(id); - if (c == NULL) { - log("channel_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); -} -void -channel_open(int id) -{ - /* XXX REMOVE ME */ - channel_start_open(id); - 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_set_fds(int id, int rfd, int wfd, int efd, int extusage) -{ - 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); - 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(); -} |