diff options
Diffstat (limited to 'channels.c')
-rw-r--r-- | channels.c | 63 |
1 files changed, 45 insertions, 18 deletions
@@ -40,7 +40,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: channels.c,v 1.70 2000/09/28 18:03:18 markus Exp $"); +RCSID("$OpenBSD: channels.c,v 1.72 2000/10/27 07:48:22 markus Exp $"); #include "ssh.h" #include "packet.h" @@ -174,7 +174,8 @@ 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) @@ -190,12 +191,16 @@ 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); + + /* enable nonblocking mode */ + if (nonblock) { + if (rfd != -1) + set_nonblock(rfd); + if (wfd != -1) + set_nonblock(wfd); + if (efd != -1) + set_nonblock(efd); + } } /* @@ -205,7 +210,7 @@ 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; @@ -245,7 +250,7 @@ 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; @@ -269,7 +274,7 @@ 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); } @@ -548,7 +553,7 @@ channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset) 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"); @@ -606,7 +611,7 @@ channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset) newch = channel_new("direct-tcpip", 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("direct-tcpip"); @@ -1514,7 +1519,7 @@ channel_request_local_forwarding(u_short port, const char *host, "port listener", SSH_CHANNEL_PORT_LISTENER, 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; @@ -1859,7 +1864,7 @@ 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. */ @@ -2045,6 +2050,28 @@ x11_input_open(int type, int plen, void *ctxt) } } +/* 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. @@ -2349,13 +2376,13 @@ channel_register_filter(int id, channel_filter_fn *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; |