X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/4c8722d9f17e771233601b107ae73e4522a24aa8..5d97cfbf8be086f7495f35675e967358d2babb7d:/channels.c diff --git a/channels.c b/channels.c index ea395293..d86cb1f0 100644 --- a/channels.c +++ b/channels.c @@ -1,40 +1,64 @@ /* - * - * channels.c - * * Author: Tatu Ylonen - * * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved - * - * Created: Fri Mar 24 16:35:24 1995 ylo - * * This file contains functions for generic socket connection forwarding. * There is also code for initiating connection forwarding for X11 connections, * arbitrary tcp/ip connections, and the authentication agent connection. * + * As far as I am concerned, the code I have written for this software + * can be used freely for any purpose. Any derived versions of this + * software must be clearly marked as such, and if the derived work is + * incompatible with the protocol description in the RFC file, it must be + * called by a name other than "ssh" or "Secure Shell". + * + * * SSH2 support added by Markus Friedl. + * Copyright (c) 1999,2000 Markus Friedl. All rights reserved. + * Copyright (c) 1999 Dug Song. All rights reserved. + * Copyright (c) 1999 Theo de Raadt. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "includes.h" -RCSID("$OpenBSD: channels.c,v 1.64 2000/07/16 08:27:21 markus Exp $"); +RCSID("$OpenBSD: channels.c,v 1.108 2001/04/14 16:17:14 markus Exp $"); + +#include +#include #include "ssh.h" +#include "ssh1.h" +#include "ssh2.h" #include "packet.h" #include "xmalloc.h" #include "buffer.h" +#include "bufaux.h" #include "uidswap.h" -#include "readconf.h" -#include "servconf.h" - +#include "log.h" +#include "misc.h" #include "channels.h" #include "nchan.h" #include "compat.h" - -#include "ssh2.h" - -#include -#include +#include "canohost.h" #include "key.h" #include "authfd.h" @@ -44,12 +68,6 @@ RCSID("$OpenBSD: channels.c,v 1.64 2000/07/16 08:27:21 markus Exp $"); /* 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. @@ -67,7 +85,7 @@ 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; +static int channel_max_fd = 0; /* Name and directory of socket for authentication agent forwarding. */ static char *channel_forwarded_auth_socket_name = NULL; @@ -78,14 +96,14 @@ 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; +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. */ char *x11_fake_data = NULL; -unsigned int x11_fake_data_len; +u_int x11_fake_data_len; /* * Data structure for storing which hosts are permitted for forward requests. @@ -113,6 +131,11 @@ 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; +/* AF_UNSPEC or AF_INET or AF_INET6 */ +extern int IPv4or6; + +void port_open_helper(Channel *c, char *rtype); + /* Sets specific protocol options. */ void @@ -121,18 +144,6 @@ 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 * @@ -157,15 +168,14 @@ channel_lookup(int id) */ void -channel_register_fds(Channel *c, int rfd, int wfd, int efd, int extusage) +channel_register_fds(Channel *c, int rfd, int wfd, int efd, + int extusage, int nonblock) { /* 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; + 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; @@ -173,12 +183,28 @@ channel_register_fds(Channel *c, int rfd, int wfd, int efd, int extusage) 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); + + /* XXX ugly hack: nonblock is only set by the server */ + if (nonblock && isatty(c->rfd)) { + debug("channel %d: rfd %d isatty", c->self, c->rfd); + c->isatty = 1; + if (!isatty(c->wfd)) { + error("channel %d: wfd %d is not a tty?", + c->self, c->wfd); + } + } else { + c->isatty = 0; + } + + /* enable nonblocking mode */ + if (nonblock) { + if (rfd != -1) + set_nonblock(rfd); + if (wfd != -1) + set_nonblock(wfd); + if (efd != -1) + set_nonblock(efd); + } } /* @@ -188,7 +214,7 @@ channel_register_fds(Channel *c, int rfd, int wfd, int efd, int extusage) int channel_new(char *ctype, int type, int rfd, int wfd, int efd, - int window, int maxpack, int extusage, char *remote_name) + int window, int maxpack, int extusage, char *remote_name, int nonblock) { int i, found; Channel *c; @@ -217,7 +243,7 @@ channel_new(char *ctype, int type, int rfd, int wfd, int efd, /* 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); + debug2("channel: expanding %d", channels_alloc); channels = xrealloc(channels, channels_alloc * sizeof(Channel)); for (i = found; i < channels_alloc; i++) channels[i].type = SSH_CHANNEL_FREE; @@ -228,7 +254,7 @@ channel_new(char *ctype, int type, int rfd, int wfd, int efd, buffer_init(&c->output); buffer_init(&c->extended); chan_init_iostates(c); - channel_register_fds(c, rfd, wfd, efd, extusage); + channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); c->self = found; c->type = type; c->ctype = ctype; @@ -244,6 +270,7 @@ channel_new(char *ctype, int type, int rfd, int wfd, int efd, c->cb_arg = NULL; c->cb_event = 0; c->dettach_user = NULL; + c->input_filter = NULL; debug("channel %d: new [%s]", found, remote_name); return found; } @@ -251,7 +278,7 @@ channel_new(char *ctype, int type, int rfd, int wfd, int efd, int channel_allocate(int type, int sock, char *remote_name) { - return channel_new("", type, sock, sock, -1, 0, 0, 0, remote_name); + return channel_new("", type, sock, sock, -1, 0, 0, 0, remote_name, 1); } @@ -284,9 +311,13 @@ void channel_free(int id) { Channel *c = channel_lookup(id); + char *s = channel_open_message(); + if (c == NULL) packet_disconnect("channel free: bad local channel %d", id); - debug("channel_free: channel %d: status: %s", id, channel_open_message()); + debug("channel_free: channel %d: status: %s", id, s); + xfree(s); + if (c->dettach_user != NULL) { debug("channel_free: channel %d: dettaching channel user", id); c->dettach_user(c->self, NULL); @@ -322,6 +353,13 @@ channel_pre_listener(Channel *c, fd_set * readset, fd_set * writeset) FD_SET(c->sock, readset); } +void +channel_pre_connecting(Channel *c, fd_set * readset, fd_set * writeset) +{ + debug3("channel %d: waiting for connection", c->self); + FD_SET(c->sock, writeset); +} + void channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset) { @@ -382,7 +420,7 @@ channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset) packet_put_int(c->remote_id); packet_send(); c->type = SSH_CHANNEL_CLOSED; - debug("Closing channel %d after input drain.", c->self); + debug("channel %d: closing after input drain.", c->self); } } @@ -406,15 +444,15 @@ channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset) int x11_open_helper(Channel *c) { - unsigned char *ucp; - unsigned int proto_len, data_len; + u_char *ucp; + u_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); + ucp = (u_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]; @@ -474,7 +512,7 @@ channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset) * We have received an X11 connection that has bad * authentication information. */ - log("X11 connection rejected because of wrong authentication.\r\n"); + log("X11 connection rejected because of wrong authentication."); buffer_clear(&c->input); buffer_clear(&c->output); close(c->sock); @@ -504,6 +542,281 @@ channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset) } } + +int +channel_decode_helper(Channel *c, int start, int lookfor) +{ + u_char *p; + int i, have; + + p = buffer_ptr(&c->input); + have = buffer_len(&c->input); + debug2("channel %d: decode_helper: start %d have %d lookfor %d", + c->self, start, have, lookfor); + if (have < start) + return 0; + for (i = start; i < have; i++) { + if (p[i] == lookfor) { + debug2("channel %d: decode_helper: matched at %d", + c->self, i); + if (lookfor == '\0' || + (i+3 < have && + p[i+1] == '\n' && + p[i+2] == '\r' && + p[i+3] == '\n')) + return i; + } + if (i > 4096) { + /* the peer is probably sending garbage */ + debug("channel %d: decode_helper: too long", + c->self); + return -1; + } + } + return 0; /* need more */ +} + +/* try to decode a http connect header */ +int +channel_decode_https(Channel *c, fd_set * readset, fd_set * writeset) +{ + u_char *p, *host, *buf; + int port, ret; + char httpok[] = "HTTP/1.0 200\r\n\r\n"; + + debug2("channel %d: decode https connect", c->self); + ret = channel_decode_helper(c, strlen("connect "), '\r'); + if (ret <= 0) + return ret; + p = buffer_ptr(&c->input); + buf = xmalloc(ret+1); + host = xmalloc(ret); + memcpy(buf, p, ret); + buf[ret] = '\0'; + if (sscanf(buf, "CONNECT %[^:]:%u HTTP/", host, &port) != 2) { + debug("channel %d: cannot parse http header", c->self); + return -1; + } + debug("channel %d: dynamic request: https host %s port %u", + c->self, host, port); + strlcpy(c->path, host, sizeof(c->path)); + c->host_port = port; + xfree(host); + xfree(buf); + buffer_consume(&c->input, ret+4); + buffer_append(&c->output, httpok, strlen(httpok)); + + return 1; +} + +/* try to decode a socks4 header */ +int +channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset) +{ + u_char *p, *host; + int len, have, ret; + 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); + ret = channel_decode_helper(c, sizeof(s4_req), '\0'); + if (ret <= 0) + return ret; + 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); + p = buffer_ptr(&c->input); + len = strlen(p); + have = buffer_len(&c->input); + debug2("channel %d: decode socks4: user %s/%d", c->self, p, len); + if (len > have) + fatal("channel %d: decode socks4: len %d > have %d", + c->self, len, have); + strlcpy(username, p, sizeof(username)); + buffer_consume(&c->input, len); + buffer_consume(&c->input, 1); /* trailing '\0' */ + + host = inet_ntoa(s4_req.dest_addr); + strlcpy(c->path, host, sizeof(c->path)); + c->host_port = ntohs(s4_req.dest_port); + + debug("channel %d: dynamic request: socks4 host %s port %u command %u", + c->self, host, c->host_port, s4_req.command); + + if (s4_req.command != 1) { + debug("channel %d: cannot handle: socks4 cn %d", + c->self, s4_req.command); + return -1; + } + s4_rsp.version = 0; /* vn: 0 for reply */ + s4_rsp.command = 90; /* cd: req granted */ + s4_rsp.dest_port = 0; /* ignored */ + s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */ + buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp)); + return 1; +} + +/* 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 + +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]; + int i, have, 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((char *)&s5_req, p, sizeof(s5_req)); + if (s5_req.version != 0x05 || + s5_req.command != SSH_SOCKS5_CONNECT || + s5_req.reserved != 0x00) { + debug("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: + debug("channel %d: bad socks5 atyp %d", c->self, s5_req.atyp); + return -1; + } + if (have < 4 + addrlen + 2) + return 0; + buffer_consume(&c->input, sizeof(s5_req)); + 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, 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); + + debug("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, (char *)&s5_rsp, sizeof(s5_rsp)); + buffer_append(&c->output, (char *)&dest_addr, sizeof(struct in_addr)); + buffer_append(&c->output, (char *)&dest_port, sizeof(dest_port)); + return 1; +} + +/* dynamic port forwarding */ +void +channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset) +{ + u_char *p; + int have, ret; + + have = buffer_len(&c->input); + + debug2("channel %d: pre_dynamic: have %d", c->self, have); + /* buffer_dump(&c->input); */ + /* check if the fixed size part of the packet is in buffer. */ + if (have < 4) { + /* need more */ + FD_SET(c->sock, readset); + return; + } + /* try to guess the protocol */ + p = buffer_ptr(&c->input); + switch (p[0]) { + case 'C': + ret = channel_decode_https(c, readset, writeset); + break; + 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) { + channel_free(c->self); + } else if (ret == 0) { + debug2("channel %d: pre_dynamic: need more", c->self); + /* need more */ + FD_SET(c->sock, readset); + } else { + /* switch to the next state */ + c->type = SSH_CHANNEL_OPENING; + port_open_helper(c, "direct-tcpip"); + } +} + /* This is our fake X11 server socket. */ void channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset) @@ -511,7 +824,7 @@ 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; + char buf[16384], *remote_ipaddr; int remote_port; if (FD_ISSET(c->sock, readset)) { @@ -522,23 +835,23 @@ channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset) error("accept: %.100s", strerror(errno)); return; } - remote_hostname = get_remote_hostname(newsock); + remote_ipaddr = get_peer_ipaddr(newsock); remote_port = get_peer_port(newsock); snprintf(buf, sizeof buf, "X11 connection from %.200s port %d", - remote_hostname, remote_port); + remote_ipaddr, remote_port); newch = channel_new("x11", SSH_CHANNEL_OPENING, newsock, newsock, -1, c->local_window_max, c->local_maxpacket, - 0, xstrdup(buf)); + 0, xstrdup(buf), 1); 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); + /* originator ipaddr and port */ + packet_put_cstring(remote_ipaddr); if (datafellows & SSH_BUG_X11FWD) { debug("ssh2 x11 bug compat mode"); } else { @@ -552,67 +865,104 @@ channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset) packet_put_string(buf, strlen(buf)); packet_send(); } - xfree(remote_hostname); + xfree(remote_ipaddr); } } +void +port_open_helper(Channel *c, char *rtype) +{ + int direct; + char buf[1024]; + char *remote_ipaddr = get_peer_ipaddr(c->sock); + u_short remote_port = get_peer_port(c->sock); + + direct = (strcmp(rtype, "direct-tcpip") == 0); + + snprintf(buf, sizeof buf, + "%s: listening port %d for %.100s port %d, " + "connect from %.200s port %d", + rtype, c->listening_port, c->path, c->host_port, + remote_ipaddr, remote_port); + + xfree(c->remote_name); + c->remote_name = xstrdup(buf); + + if (compat20) { + packet_start(SSH2_MSG_CHANNEL_OPEN); + packet_put_cstring(rtype); + packet_put_int(c->self); + packet_put_int(c->local_window_max); + packet_put_int(c->local_maxpacket); + if (direct) { + /* target host, port */ + packet_put_cstring(c->path); + packet_put_int(c->host_port); + } else { + /* listen address, port */ + packet_put_cstring(c->path); + packet_put_int(c->listening_port); + } + /* originator host and port */ + packet_put_cstring(remote_ipaddr); + packet_put_int(remote_port); + packet_send(); + } else { + packet_start(SSH_MSG_PORT_OPEN); + packet_put_int(c->self); + packet_put_cstring(c->path); + packet_put_int(c->host_port); + if (have_hostname_in_open) + packet_put_cstring(c->remote_name); + packet_send(); + } + xfree(remote_ipaddr); +} + /* * This socket is listening for connections to a forwarded TCP/IP port. */ void channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset) { + Channel *nc; struct sockaddr addr; - int newsock, newch; + int newsock, newch, nextstate; socklen_t addrlen; - char buf[1024], *remote_hostname; - int remote_port; + char *rtype; if (FD_ISSET(c->sock, readset)) { debug("Connection to port %d forwarding " "to %.100s port %d requested.", c->listening_port, c->path, c->host_port); + + rtype = (c->type == SSH_CHANNEL_RPORT_LISTENER) ? + "forwarded-tcpip" : "direct-tcpip"; + nextstate = (c->host_port == 0) ? SSH_CHANNEL_DYNAMIC : + SSH_CHANNEL_OPENING; + 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, + newch = channel_new(rtype, + nextstate, 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(); + 0, xstrdup(rtype), 1); + + nc = channel_lookup(newch); + if (nc == NULL) { + error("xxx: no new channel:"); + return; } - xfree(remote_hostname); + nc->listening_port = c->listening_port; + nc->host_port = c->host_port; + strlcpy(nc->path, c->path, sizeof(nc->path)); + + if (nextstate != SSH_CHANNEL_DYNAMIC) + port_open_helper(nc, rtype); } } @@ -634,14 +984,46 @@ channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset) 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); + newch = channel_new("accepted auth socket", + SSH_CHANNEL_OPENING, newsock, newsock, -1, + c->local_window_max, c->local_maxpacket, + 0, xstrdup("accepted auth socket"), 1); + if (compat20) { + packet_start(SSH2_MSG_CHANNEL_OPEN); + packet_put_cstring("auth-agent@openssh.com"); + packet_put_int(newch); + packet_put_int(c->local_window_max); + packet_put_int(c->local_maxpacket); + } else { + packet_start(SSH_SMSG_AGENT_OPEN); + packet_put_int(newch); + } packet_send(); } } +void +channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset) +{ + if (FD_ISSET(c->sock, writeset)) { + int err = 0; + int sz = sizeof(err); + c->type = SSH_CHANNEL_OPEN; + if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err, &sz) < 0) { + debug("getsockopt SO_ERROR failed"); + } else { + if (err == 0) { + debug("channel %d: connected)", c->self); + } else { + debug("channel %d: not connected: %s", + c->self, strerror(err)); + chan_read_failed(c); + chan_write_failed(c); + } + } + } +} + int channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset) { @@ -656,22 +1038,34 @@ channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset) if (len <= 0) { debug("channel %d: read<=0 rfd %d len %d", c->self, c->rfd, len); - if (compat13) { + if (c->type != SSH_CHANNEL_OPEN) { + debug("channel %d: not open", c->self); + channel_free(c->self); + return -1; + } else 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); + debug("channel %d: status set to input draining.", c->self); } else { chan_read_failed(c); } return -1; } - buffer_append(&c->input, buf, len); + if(c->input_filter != NULL) { + if (c->input_filter(c, buf, len) == -1) { + debug("channel %d: filter stops", c->self); + chan_read_failed(c); + } + } else { + buffer_append(&c->input, buf, len); + } } return 1; } int channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset) { + struct termios tio; int len; /* Send buffered output data to the socket. */ @@ -683,15 +1077,32 @@ channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset) if (len < 0 && (errno == EINTR || errno == EAGAIN)) return 1; if (len <= 0) { - if (compat13) { + if (c->type != SSH_CHANNEL_OPEN) { + debug("channel %d: not open", c->self); + channel_free(c->self); + return -1; + } else if (compat13) { buffer_consume(&c->output, buffer_len(&c->output)); - debug("Channel %d status set to input draining.", c->self); + debug("channel %d: status set to input draining.", c->self); c->type = SSH_CHANNEL_INPUT_DRAINING; } else { chan_write_failed(c); } return -1; } + if (compat20 && c->isatty) { + if (tcgetattr(c->wfd, &tio) == 0 && + !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) { + /* + * Simulate echo to reduce the impact of + * traffic analysis. We need to match the + * size of a SSH2_MSG_CHANNEL_DATA message + * (4 byte channel id + data) + */ + packet_send_ignore(4 + len); + packet_send(); + } + } buffer_consume(&c->output, len); if (compat20 && len > 0) { c->local_consumed += len; @@ -712,39 +1123,50 @@ channel_handle_efd(Channel *c, fd_set * readset, fd_set * 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", + debug2("channel %d: written %d to efd %d", c->self, len, c->efd); - if (len > 0) { + if (len < 0 && (errno == EINTR || errno == EAGAIN)) + return 1; + if (len <= 0) { + debug2("channel %d: closing write-efd %d", + c->self, c->efd); + close(c->efd); + c->efd = -1; + } else { buffer_consume(&c->extended, len); c->local_consumed += len; } } else if (c->extended_usage == CHAN_EXTENDED_READ && FD_ISSET(c->efd, readset)) { len = read(c->efd, buf, sizeof(buf)); - debug("channel %d: read %d from efd %d", + debug2("channel %d: read %d from efd %d", c->self, len, c->efd); - if (len == 0) { - debug("channel %d: closing efd %d", + if (len < 0 && (errno == EINTR || errno == EAGAIN)) + return 1; + if (len <= 0) { + debug2("channel %d: closing read-efd %d", c->self, c->efd); close(c->efd); c->efd = -1; - } else if (len > 0) + } else { buffer_append(&c->extended, buf, len); + } } } return 1; } int -channel_check_window(Channel *c, fd_set * readset, fd_set * writeset) +channel_check_window(Channel *c) { - if (!(c->flags & (CHAN_CLOSE_SENT|CHAN_CLOSE_RCVD)) && + 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(); - debug("channel %d: window %d sent adjust %d", + debug2("channel %d: window %d sent adjust %d", c->self, c->local_window, c->local_consumed); c->local_window += c->local_consumed; @@ -766,7 +1188,8 @@ 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); + + channel_check_window(c); } void @@ -790,11 +1213,19 @@ channel_handler_init_20(void) channel_pre[SSH_CHANNEL_OPEN] = &channel_pre_open_20; channel_pre[SSH_CHANNEL_X11_OPEN] = &channel_pre_x11_open; channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; + channel_pre[SSH_CHANNEL_RPORT_LISTENER] = &channel_pre_listener; channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; + channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; + channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; + channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_2; channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; + channel_post[SSH_CHANNEL_RPORT_LISTENER] = &channel_post_port_listener; channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; + channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; + channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; + channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_2; } void @@ -807,12 +1238,16 @@ channel_handler_init_13(void) channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; channel_pre[SSH_CHANNEL_INPUT_DRAINING] = &channel_pre_input_draining; channel_pre[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_pre_output_draining; + channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; + channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1; channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; channel_post[SSH_CHANNEL_OUTPUT_DRAINING] = &channel_post_output_drain_13; + channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; + channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1; } void @@ -823,11 +1258,15 @@ channel_handler_init_15(void) channel_pre[SSH_CHANNEL_X11_LISTENER] = &channel_pre_listener; channel_pre[SSH_CHANNEL_PORT_LISTENER] = &channel_pre_listener; channel_pre[SSH_CHANNEL_AUTH_SOCKET] = &channel_pre_listener; + channel_pre[SSH_CHANNEL_CONNECTING] = &channel_pre_connecting; + channel_pre[SSH_CHANNEL_DYNAMIC] = &channel_pre_dynamic; channel_post[SSH_CHANNEL_X11_LISTENER] = &channel_post_x11_listener; channel_post[SSH_CHANNEL_PORT_LISTENER] = &channel_post_port_listener; channel_post[SSH_CHANNEL_AUTH_SOCKET] = &channel_post_auth_listener; channel_post[SSH_CHANNEL_OPEN] = &channel_post_open_1; + channel_post[SSH_CHANNEL_CONNECTING] = &channel_post_connecting; + channel_post[SSH_CHANNEL_DYNAMIC] = &channel_post_open_1; } void @@ -864,14 +1303,51 @@ channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset) if (ftab[c->type] == NULL) continue; (*ftab[c->type])(c, readset, writeset); - chan_delete_if_full_closed(c); + if (chan_is_dead(c)) { + /* + * we have to remove the fd's from the select mask + * before the channels are free'd and the fd's are + * closed + */ + if (c->wfd != -1) + FD_CLR(c->wfd, writeset); + if (c->rfd != -1) + FD_CLR(c->rfd, readset); + if (c->efd != -1) { + if (c->extended_usage == CHAN_EXTENDED_READ) + FD_CLR(c->efd, readset); + if (c->extended_usage == CHAN_EXTENDED_WRITE) + FD_CLR(c->efd, writeset); + } + channel_free(c->self); + } } } void -channel_prepare_select(fd_set * readset, fd_set * writeset) +channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp, + int rekeying) { - channel_handler(channel_pre, readset, writeset); + int n; + u_int sz; + + n = MAX(*maxfdp, channel_max_fd); + + sz = howmany(n+1, NFDBITS) * sizeof(fd_mask); + if (*readsetp == NULL || n > *maxfdp) { + if (*readsetp) + xfree(*readsetp); + if (*writesetp) + xfree(*writesetp); + *readsetp = xmalloc(sz); + *writesetp = xmalloc(sz); + *maxfdp = n; + } + memset(*readsetp, 0, sz); + memset(*writesetp, 0, sz); + + if (!rekeying) + channel_handler(channel_pre, *readsetp, *writesetp); } void @@ -880,7 +1356,7 @@ 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. */ +/* If there is data to send to the connection, enqueue some of it now. */ void channel_output_poll() @@ -899,19 +1375,18 @@ channel_output_poll() } 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); + /* XXX is this true? */ + debug2("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) { + if ((c->istate == CHAN_INPUT_OPEN || + c->istate == CHAN_INPUT_WAIT_DRAIN) && + (len = buffer_len(&c->input)) > 0) { /* Send some data for the other side over the secure connection. */ if (compat20) { if (len > c->remote_window) @@ -951,6 +1426,9 @@ channel_output_poll() c->remote_window > 0 && (len = buffer_len(&c->extended)) > 0 && c->extended_usage == CHAN_EXTENDED_READ) { + debug2("channel %d: rwin %d elen %d euse %d", + c->self, c->remote_window, buffer_len(&c->extended), + c->extended_usage); if (len > c->remote_window) len = c->remote_window; if (len > c->remote_maxpacket) @@ -962,6 +1440,7 @@ channel_output_poll() packet_send(); buffer_consume(&c->extended, len); c->remote_window -= len; + debug2("channel %d: sent ext data %d", c->self, len); } } } @@ -973,11 +1452,11 @@ channel_output_poll() */ void -channel_input_data(int type, int plen) +channel_input_data(int type, int plen, void *ctxt) { int id; char *data; - unsigned int data_len; + u_int data_len; Channel *c; /* Get the channel number and verify it. */ @@ -1018,12 +1497,12 @@ channel_input_data(int type, int plen) xfree(data); } void -channel_input_extended_data(int type, int plen) +channel_input_extended_data(int type, int plen, void *ctxt) { int id; int tcode; char *data; - unsigned int data_len; + u_int data_len; Channel *c; /* Get the channel number and verify it. */ @@ -1051,7 +1530,7 @@ channel_input_extended_data(int type, int plen) xfree(data); return; } - debug("channel %d: rcvd ext data %d", c->self, data_len); + 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); @@ -1066,7 +1545,7 @@ channel_input_extended_data(int type, int plen) int channel_not_very_much_buffered_data() { - unsigned int i; + u_int i; Channel *c; for (i = 0; i < channels_alloc; i++) { @@ -1088,7 +1567,7 @@ channel_not_very_much_buffered_data() } void -channel_input_ieof(int type, int plen) +channel_input_ieof(int type, int plen, void *ctxt) { int id; Channel *c; @@ -1103,7 +1582,7 @@ channel_input_ieof(int type, int plen) } void -channel_input_close(int type, int plen) +channel_input_close(int type, int plen, void *ctxt) { int id; Channel *c; @@ -1142,7 +1621,7 @@ channel_input_close(int type, int plen) /* proto version 1.5 overloads CLOSE_CONFIRMATION with OCLOSE */ void -channel_input_oclose(int type, int plen) +channel_input_oclose(int type, int plen, void *ctxt) { int id = packet_get_int(); Channel *c = channel_lookup(id); @@ -1153,7 +1632,7 @@ channel_input_oclose(int type, int plen) } void -channel_input_close_confirmation(int type, int plen) +channel_input_close_confirmation(int type, int plen, void *ctxt) { int id = packet_get_int(); Channel *c = channel_lookup(id); @@ -1169,7 +1648,7 @@ channel_input_close_confirmation(int type, int plen) } void -channel_input_open_confirmation(int type, int plen) +channel_input_open_confirmation(int type, int plen, void *ctxt) { int id, remote_id; Channel *c; @@ -1193,9 +1672,9 @@ channel_input_open_confirmation(int type, int plen) c->remote_maxpacket = packet_get_int(); packet_done(); if (c->cb_fn != NULL && c->cb_event == type) { - debug("callback start"); + debug2("callback start"); c->cb_fn(c->self, c->cb_arg); - debug("callback done"); + debug2("callback done"); } debug("channel %d: open confirm rwindow %d rmax %d", c->self, c->remote_window, c->remote_maxpacket); @@ -1203,9 +1682,10 @@ channel_input_open_confirmation(int type, int plen) } void -channel_input_open_failure(int type, int plen) +channel_input_open_failure(int type, int plen, void *ctxt) { - int id; + int id, reason; + char *msg = NULL, *lang = NULL; Channel *c; if (!compat20) @@ -1218,20 +1698,25 @@ channel_input_open_failure(int type, int plen) 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); + reason = packet_get_int(); + if (packet_remaining() > 0) { + msg = packet_get_string(NULL); + lang = packet_get_string(NULL); + } packet_done(); - xfree(msg); - xfree(lang); + log("channel_open_failure: %d: reason %d %s", id, + reason, msg ? msg : ""); + if (msg != NULL) + xfree(msg); + if (lang != NULL) + xfree(lang); } /* Free the channel. This will also close the socket. */ channel_free(id); } void -channel_input_channel_request(int type, int plen) +channel_input_channel_request(int type, int plen, void *ctxt) { int id; Channel *c; @@ -1244,19 +1729,19 @@ channel_input_channel_request(int type, int plen) packet_disconnect("Received request for " "non-open channel %d.", id); if (c->cb_fn != NULL && c->cb_event == type) { - debug("callback start"); + debug2("callback start"); c->cb_fn(c->self, c->cb_arg); - debug("callback done"); + debug2("callback done"); } else { char *service = packet_get_string(NULL); - debug("channel: %d rcvd request for %s", c->self, service); -debug("cb_fn %p cb_event %d", c->cb_fn , c->cb_event); + 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_input_window_adjust(int type, int plen, void *ctxt) { Channel *c; int id, adjust; @@ -1275,7 +1760,7 @@ channel_input_window_adjust(int type, int plen) } adjust = packet_get_int(); packet_done(); - debug("channel %d: rcvd adjust %d", id, adjust); + debug2("channel %d: rcvd adjust %d", id, adjust); c->remote_window += adjust; } @@ -1292,10 +1777,11 @@ channel_stop_listening() switch (channels[i].type) { case SSH_CHANNEL_AUTH_SOCKET: close(channels[i].sock); - remove(channels[i].path); + unlink(channels[i].path); channel_free(i); break; case SSH_CHANNEL_PORT_LISTENER: + case SSH_CHANNEL_RPORT_LISTENER: case SSH_CHANNEL_X11_LISTENER: close(channels[i].sock); channel_free(i); @@ -1320,27 +1806,22 @@ channel_close_all() 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; + u_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_RPORT_LISTENER: case SSH_CHANNEL_CLOSED: case SSH_CHANNEL_AUTH_SOCKET: + case SSH_CHANNEL_DYNAMIC: + case SSH_CHANNEL_CONNECTING: /* XXX ??? */ continue; case SSH_CHANNEL_LARVAL: if (!compat20) @@ -1362,6 +1843,41 @@ channel_still_open() return 0; } +/* Returns the id of an open channel suitable for keepaliving */ + +int +channel_find_open() +{ + u_int i; + for (i = 0; i < channels_alloc; i++) + switch (channels[i].type) { + case SSH_CHANNEL_CLOSED: + case SSH_CHANNEL_DYNAMIC: + case SSH_CHANNEL_FREE: + case SSH_CHANNEL_X11_LISTENER: + case SSH_CHANNEL_PORT_LISTENER: + case SSH_CHANNEL_RPORT_LISTENER: + case SSH_CHANNEL_OPENING: + continue; + case SSH_CHANNEL_LARVAL: + case SSH_CHANNEL_AUTH_SOCKET: + case SSH_CHANNEL_CONNECTING: /* XXX ??? */ + 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", channels[i].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 @@ -1384,11 +1900,14 @@ channel_open_message() case SSH_CHANNEL_FREE: case SSH_CHANNEL_X11_LISTENER: case SSH_CHANNEL_PORT_LISTENER: + case SSH_CHANNEL_RPORT_LISTENER: case SSH_CHANNEL_CLOSED: case SSH_CHANNEL_AUTH_SOCKET: 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: @@ -1416,19 +1935,48 @@ channel_open_message() * Initiate forwarding of connections to local port "port" through the secure * channel to host:port from remote side. */ +int +channel_request_local_forwarding(u_short listen_port, const char *host_to_connect, + u_short port_to_connect, int gateway_ports) +{ + return channel_request_forwarding( + NULL, listen_port, + host_to_connect, port_to_connect, + gateway_ports, /*remote_fwd*/ 0); +} -void -channel_request_local_forwarding(u_short port, const char *host, - u_short host_port, int gateway_ports) +/* + * If 'remote_fwd' is true we have a '-R style' listener for protocol 2 + * (SSH_CHANNEL_RPORT_LISTENER). + */ +int +channel_request_forwarding( + const char *listen_address, u_short listen_port, + const char *host_to_connect, u_short port_to_connect, + int gateway_ports, int remote_fwd) { - int success, ch, sock, on = 1; + int success, ch, sock, on = 1, ctype; struct addrinfo hints, *ai, *aitop; char ntop[NI_MAXHOST], strport[NI_MAXSERV]; + const char *host; struct linger linger; - if (strlen(host) > sizeof(channels[0].path) - 1) - packet_disconnect("Forward host name too long."); + success = 0; + + if (remote_fwd) { + host = listen_address; + ctype = SSH_CHANNEL_RPORT_LISTENER; + } else { + host = host_to_connect; + ctype =SSH_CHANNEL_PORT_LISTENER; + } + if (strlen(host) > sizeof(channels[0].path) - 1) { + error("Forward host name too long."); + return success; + } + + /* XXX listen_address is currently ignored */ /* * getaddrinfo returns a loopback address if the hostname is * set to NULL and hints.ai_flags is not AI_PASSIVE @@ -1437,17 +1985,16 @@ channel_request_local_forwarding(u_short port, const char *host, hints.ai_family = IPv4or6; hints.ai_flags = gateway_ports ? AI_PASSIVE : 0; hints.ai_socktype = SOCK_STREAM; - snprintf(strport, sizeof strport, "%d", port); + snprintf(strport, sizeof strport, "%d", listen_port); if (getaddrinfo(NULL, strport, &hints, &aitop) != 0) packet_disconnect("getaddrinfo: fatal error"); - success = 0; for (ai = aitop; ai; ai = ai->ai_next) { if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) continue; if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { - error("channel_request_local_forwarding: getnameinfo failed"); + error("channel_request_forwarding: getnameinfo failed"); continue; } /* Create a port to listen for the host. */ @@ -1474,7 +2021,7 @@ channel_request_local_forwarding(u_short port, const char *host, error("bind: %.100s", strerror(errno)); else verbose("bind: %.100s", strerror(errno)); - + close(sock); continue; } @@ -1485,19 +2032,19 @@ channel_request_local_forwarding(u_short port, const char *host, continue; } /* Allocate a channel number for the socket. */ - ch = channel_new( - "port listener", SSH_CHANNEL_PORT_LISTENER, - sock, sock, -1, + ch = channel_new("port listener", ctype, sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, - 0, xstrdup("port listener")); + 0, xstrdup("port listener"), 1); strlcpy(channels[ch].path, host, sizeof(channels[ch].path)); - channels[ch].host_port = host_port; - channels[ch].listening_port = port; + channels[ch].host_port = port_to_connect; + channels[ch].listening_port = listen_port; success = 1; } if (success == 0) - packet_disconnect("cannot listen port: %d", port); + error("channel_request_forwarding: cannot listen to port: %d", + listen_port); freeaddrinfo(aitop); + return success; } /* @@ -1506,19 +2053,15 @@ channel_request_local_forwarding(u_short port, const char *host, */ void -channel_request_remote_forwarding(u_short listen_port, const char *host_to_connect, - u_short port_to_connect) +channel_request_remote_forwarding(u_short listen_port, + const char *host_to_connect, u_short port_to_connect) { - int payload_len; + int payload_len, type, success = 0; + /* Record locally that connection to this host/port is permitted. */ if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) fatal("channel_request_remote_forwarding: too many forwards"); - permitted_opens[num_permitted_opens].host_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"; @@ -1527,6 +2070,10 @@ channel_request_remote_forwarding(u_short listen_port, const char *host_to_conne packet_put_char(0); /* boolean: want reply */ packet_put_cstring(address_to_bind); packet_put_int(listen_port); + packet_send(); + packet_write_wait(); + /* Assume that server accepts the request */ + success = 1; } else { packet_start(SSH_CMSG_PORT_FORWARD_REQUEST); packet_put_int(listen_port); @@ -1534,11 +2081,27 @@ channel_request_remote_forwarding(u_short listen_port, const char *host_to_conne packet_put_int(port_to_connect); packet_send(); packet_write_wait(); - /* - * Wait for response from the remote side. It will send a disconnect - * message on failure, and we will never see it here. - */ - packet_read_expect(&payload_len, SSH_SMSG_SUCCESS); + + /* Wait for response from the remote side. */ + type = packet_read(&payload_len); + switch (type) { + case SSH_SMSG_SUCCESS: + success = 1; + break; + case SSH_SMSG_FAILURE: + log("Warning: Server denied remote port forwarding."); + break; + default: + /* Unknown packet */ + packet_disconnect("Protocol error for port forward request:" + "received packet type %d.", type); + } + } + if (success) { + permitted_opens[num_permitted_opens].host_to_connect = xstrdup(host_to_connect); + permitted_opens[num_permitted_opens].port_to_connect = port_to_connect; + permitted_opens[num_permitted_opens].listen_port = listen_port; + num_permitted_opens++; } } @@ -1559,6 +2122,7 @@ channel_input_port_forward_request(int is_root, int gateway_ports) 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. @@ -1566,18 +2130,55 @@ channel_input_port_forward_request(int is_root, int gateway_ports) if (port < IPPORT_RESERVED && !is_root) packet_disconnect("Requested forwarding of port %d but user is not root.", port); - /* - * Initiate forwarding, - */ +#endif + /* Initiate forwarding */ channel_request_local_forwarding(port, hostname, host_port, gateway_ports); /* Free the argument string. */ xfree(hostname); } -/* XXX move to aux.c */ +/* + * Permits opening to any host/port if permitted_opens[] is empty. This is + * usually called by the server, because the user could connect to any port + * anyway, and the server has no way to know but to trust the client anyway. + */ +void +channel_permit_all_opens() +{ + if (num_permitted_opens == 0) + all_opens_permitted = 1; +} + +void +channel_add_permitted_opens(char *host, int port) +{ + if (num_permitted_opens >= SSH_MAX_FORWARDS_PER_DIRECTION) + fatal("channel_request_remote_forwarding: too many forwards"); + debug("allow port forwarding to host %s port %d", host, port); + + 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; +} + +void +channel_clear_permitted_opens(void) +{ + int i; + + for (i = 0; i < num_permitted_opens; i++) + xfree(permitted_opens[i].host_to_connect); + num_permitted_opens = 0; + +} + + +/* return socket to remote host, port */ int -channel_connect_to(const char *host, u_short host_port) +connect_to(const char *host, u_short port) { struct addrinfo hints, *ai, *aitop; char ntop[NI_MAXHOST], strport[NI_MAXSERV]; @@ -1587,9 +2188,10 @@ channel_connect_to(const char *host, u_short host_port) memset(&hints, 0, sizeof(hints)); hints.ai_family = IPv4or6; hints.ai_socktype = SOCK_STREAM; - snprintf(strport, sizeof strport, "%d", host_port); + snprintf(strport, sizeof strport, "%d", port); if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) { - error("%.100s: unknown host (%s)", host, gai_strerror(gaierr)); + error("connect_to %.100s: unknown host (%s)", host, + gai_strerror(gaierr)); return -1; } for (ai = aitop; ai; ai = ai->ai_next) { @@ -1597,34 +2199,72 @@ channel_connect_to(const char *host, u_short host_port) 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"); + error("connect_to: getnameinfo failed"); continue; } - /* Create the socket. */ sock = socket(ai->ai_family, SOCK_STREAM, 0); if (sock < 0) { error("socket: %.100s", strerror(errno)); continue; } - /* Connect to the host/port. */ - if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0) { - error("connect %.100s port %s: %.100s", ntop, strport, + if (fcntl(sock, F_SETFL, O_NONBLOCK) < 0) + fatal("connect_to: F_SETFL: %s", strerror(errno)); + if (connect(sock, ai->ai_addr, ai->ai_addrlen) < 0 && + errno != EINPROGRESS) { + error("connect_to %.100s port %s: %.100s", ntop, strport, strerror(errno)); close(sock); - continue; /* fail -- try next */ + continue; /* fail -- try next */ } break; /* success */ } freeaddrinfo(aitop); if (!ai) { - error("connect %.100s port %d: failed.", host, host_port); + error("connect_to %.100s port %d: failed.", host, port); return -1; } /* success */ return sock; } +int +channel_connect_by_listen_adress(u_short listen_port) +{ + int i; + + for (i = 0; i < num_permitted_opens; i++) + if (permitted_opens[i].listen_port == listen_port) + return connect_to( + permitted_opens[i].host_to_connect, + permitted_opens[i].port_to_connect); + error("WARNING: Server requests forwarding for unknown listen_port %d", + listen_port); + return -1; +} + +/* Check if connecting to that port is permitted and connect. */ +int +channel_connect_to(const char *host, u_short port) +{ + int i, permit; + + permit = all_opens_permitted; + if (!permit) { + for (i = 0; i < num_permitted_opens; i++) + if (permitted_opens[i].port_to_connect == port && + strcmp(permitted_opens[i].host_to_connect, host) == 0) + permit = 1; + + } + if (!permit) { + log("Received request to connect to host %.100s port %d, " + "but the request was denied.", host, port); + return -1; + } + return connect_to(host, port); +} + /* * This is called after receiving PORT_OPEN message. This attempts to * connect to the given host:port, and sends back CHANNEL_OPEN_CONFIRMATION @@ -1632,57 +2272,29 @@ channel_connect_to(const char *host, u_short host_port) */ void -channel_input_port_open(int type, int plen) +channel_input_port_open(int type, int plen, void *ctxt) { u_short host_port; char *host, *originator_string; - int remote_channel, sock = -1, newch, i, denied; - unsigned int host_len, originator_len; + int remote_channel, sock = -1, newch; - /* 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 = packet_get_string(NULL); 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 */ + originator_string = packet_get_string(NULL); } 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); + packet_done(); + sock = channel_connect_to(host, host_port); + if (sock != -1) { + newch = channel_allocate(SSH_CHANNEL_CONNECTING, + sock, originator_string); channels[newch].remote_id = remote_channel; + /*XXX delay answer? */ packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); packet_put_int(remote_channel); packet_put_int(newch); @@ -1732,11 +2344,12 @@ x11_create_display_inet(int screen_number, int x11_display_offset) continue; sock = socket(ai->ai_family, SOCK_STREAM, 0); if (sock < 0) { - if (errno != EINVAL) { + if ((errno != EINVAL) && (errno != EAFNOSUPPORT)) { error("socket: %.100s", strerror(errno)); return NULL; } else { - debug("Socket family %d not supported [X11 disp create]", ai->ai_family); + debug("x11_create_display_inet: Socket family %d not supported", + ai->ai_family); continue; } } @@ -1763,6 +2376,7 @@ x11_create_display_inet(int screen_number, int x11_display_offset) break; #endif } + freeaddrinfo(aitop); if (num_socks > 0) break; } @@ -1782,12 +2396,11 @@ x11_create_display_inet(int screen_number, int x11_display_offset) } /* Set up a suitable value for the DISPLAY variable. */ - if (gethostname(hostname, sizeof(hostname)) < 0) fatal("gethostname: %.100s", strerror(errno)); #ifdef IPADDR_IN_DISPLAY - /* + /* * HPUX detects the local hostname in the DISPLAY variable and tries * to set up a shared memory connection to the server, which it * incorrectly supposes to be local. @@ -1816,13 +2429,13 @@ x11_create_display_inet(int screen_number, int x11_display_offset) memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr)); /* Set DISPLAY to :screen.display */ - snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr), - display_number, screen_number); + snprintf(display, sizeof(display), "%.50s:%d.%d", inet_ntoa(my_addr), + display_number, screen_number); } #else /* IPADDR_IN_DISPLAY */ /* Just set DISPLAY to hostname:screen.display */ snprintf(display, sizeof display, "%.400s:%d.%d", hostname, - display_number, screen_number); + display_number, screen_number); #endif /* IPADDR_IN_DISPLAY */ /* Allocate a channel for each socket. */ @@ -1831,7 +2444,7 @@ x11_create_display_inet(int screen_number, int x11_display_offset) (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")); + 0, xstrdup("X11 inet listener"), 1); } /* Return a suitable value for the DISPLAY environment variable. */ @@ -1844,7 +2457,7 @@ x11_create_display_inet(int screen_number, int x11_display_offset) static int -connect_local_xsocket(unsigned int dnr) +connect_local_xsocket(u_int dnr) { static const char *const x_sockets[] = { X_UNIX_PATH "%u", @@ -1973,11 +2586,11 @@ x11_connect_display(void) */ void -x11_input_open(int type, int plen) +x11_input_open(int type, int plen, void *ctxt) { int remote_channel, sock = 0, newch; char *remote_host; - unsigned int remote_len; + u_int remote_len; /* Get remote channel number. */ remote_channel = packet_get_int(); @@ -2017,6 +2630,28 @@ x11_input_open(int type, int plen) } } +/* dummy protocol handler that denies SSH-1 requests (agent/x11) */ +void +deny_input_open(int type, int plen, void *ctxt) +{ + int rchan = packet_get_int(); + switch(type){ + case SSH_SMSG_AGENT_OPEN: + error("Warning: ssh server tried agent forwarding."); + break; + case SSH_SMSG_X11_OPEN: + error("Warning: ssh server tried X11 forwarding."); + break; + default: + error("deny_input_open: type %d plen %d", type, plen); + break; + } + error("Warning: this is probably a break in attempt by a malicious server."); + packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); + packet_put_int(rchan); + packet_send(); +} + /* * Requests forwarding of X11 connections, generates fake authentication * data, and enables authentication spoofing. @@ -2026,8 +2661,8 @@ void x11_request_forwarding_with_spoofing(int client_session_id, const char *proto, const char *data) { - unsigned int data_len = (unsigned int) strlen(data) / 2; - unsigned int i, value; + u_int data_len = (u_int) strlen(data) / 2; + u_int i, value, len; char *new_data; int screen_number; const char *cp; @@ -2065,9 +2700,11 @@ x11_request_forwarding_with_spoofing(int client_session_id, x11_fake_data_len = data_len; /* Convert the fake data into hex. */ - new_data = xmalloc(2 * data_len + 1); + len = 2 * data_len + 1; + new_data = xmalloc(len); for (i = 0; i < data_len; i++) - sprintf(new_data + 2 * i, "%02x", (unsigned char) x11_fake_data[i]); + snprintf(new_data + 2 * i, len - 2 * i, + "%02x", (u_char) x11_fake_data[i]); /* Send the request packet. */ if (compat20) { @@ -2111,7 +2748,7 @@ auth_get_socket_name() void cleanup_socket(void) { - remove(channel_forwarded_auth_socket_name); + unlink(channel_forwarded_auth_socket_name); rmdir(channel_forwarded_auth_socket_dir); } @@ -2130,7 +2767,7 @@ auth_input_request_forwarding(struct passwd * pw) fatal("Protocol error: authentication forwarding requested twice."); /* Temporarily drop privileged uid for mkdir/bind. */ - temporarily_use_uid(pw->pw_uid); + temporarily_use_uid(pw); /* Allocate a buffer for the socket name, and format the name. */ channel_forwarded_auth_socket_name = xmalloc(MAX_SOCKET_NAME); @@ -2178,8 +2815,11 @@ auth_input_request_forwarding(struct passwd * pw) packet_disconnect("listen: %.100s", strerror(errno)); /* Allocate a channel for the authentication agent socket. */ - newch = channel_allocate(SSH_CHANNEL_AUTH_SOCKET, sock, - xstrdup("auth socket")); + newch = channel_new("auth socket", + SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1, + CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, + 0, xstrdup("auth socket"), 1); + strlcpy(channels[newch].path, channel_forwarded_auth_socket_name, sizeof(channels[newch].path)); return 1; @@ -2188,7 +2828,7 @@ auth_input_request_forwarding(struct passwd * pw) /* This is called to process an SSH_SMSG_AGENT_OPEN message. */ void -auth_input_open_request(int type, int plen) +auth_input_open_request(int type, int plen, void *ctxt) { int remch, sock, newch; char *dummyname; @@ -2309,18 +2949,28 @@ channel_cancel_cleanup(int id) } c->dettach_user = NULL; } +void +channel_register_filter(int id, channel_filter_fn *fn) +{ + Channel *c = channel_lookup(id); + if (c == NULL) { + log("channel_register_filter: %d: bad id", id); + return; + } + c->input_filter = fn; +} void -channel_set_fds(int id, int rfd, int wfd, int efd, int extusage) +channel_set_fds(int id, int rfd, int wfd, int efd, + int extusage, int nonblock) { Channel *c = channel_lookup(id); if (c == NULL || c->type != SSH_CHANNEL_LARVAL) fatal("channel_activate for non-larval channel %d.", id); - - channel_register_fds(c, rfd, wfd, efd, extusage); + channel_register_fds(c, rfd, wfd, efd, extusage, nonblock); c->type = SSH_CHANNEL_OPEN; /* XXX window size? */ - c->local_window = c->local_window_max = c->local_maxpacket/2; + 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);