+void
+channel_pre_open_13(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ if (buffer_len(&c->input) < packet_get_maxsize())
+ FD_SET(c->sock, readset);
+ if (buffer_len(&c->output) > 0)
+ FD_SET(c->sock, writeset);
+}
+
+void
+channel_pre_open_15(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ /* test whether sockets are 'alive' for read/write */
+ if (c->istate == CHAN_INPUT_OPEN)
+ if (buffer_len(&c->input) < packet_get_maxsize())
+ FD_SET(c->sock, readset);
+ if (c->ostate == CHAN_OUTPUT_OPEN ||
+ c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
+ if (buffer_len(&c->output) > 0) {
+ FD_SET(c->sock, writeset);
+ } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
+ chan_obuf_empty(c);
+ }
+ }
+}
+
+void
+channel_pre_open_20(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ if (c->istate == CHAN_INPUT_OPEN &&
+ c->remote_window > 0 &&
+ buffer_len(&c->input) < c->remote_window)
+ FD_SET(c->rfd, readset);
+ if (c->ostate == CHAN_OUTPUT_OPEN ||
+ c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
+ if (buffer_len(&c->output) > 0) {
+ FD_SET(c->wfd, writeset);
+ } else if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN) {
+ chan_obuf_empty(c);
+ }
+ }
+ /** XXX check close conditions, too */
+ if (c->efd != -1) {
+ if (c->extended_usage == CHAN_EXTENDED_WRITE &&
+ buffer_len(&c->extended) > 0)
+ FD_SET(c->efd, writeset);
+ else if (c->extended_usage == CHAN_EXTENDED_READ &&
+ buffer_len(&c->extended) < c->remote_window)
+ FD_SET(c->efd, readset);
+ }
+}
+
+void
+channel_pre_input_draining(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ if (buffer_len(&c->input) == 0) {
+ packet_start(SSH_MSG_CHANNEL_CLOSE);
+ packet_put_int(c->remote_id);
+ packet_send();
+ c->type = SSH_CHANNEL_CLOSED;
+ debug("channel %d: closing after input drain.", c->self);
+ }
+}
+
+void
+channel_pre_output_draining(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ if (buffer_len(&c->output) == 0)
+ chan_mark_dead(c);
+ else
+ FD_SET(c->sock, writeset);
+}
+
+/*
+ * This is a special state for X11 authentication spoofing. An opened X11
+ * connection (when authentication spoofing is being done) remains in this
+ * state until the first packet has been completely read. The authentication
+ * data in that packet is then substituted by the real data if it matches the
+ * fake data, and the channel is put into normal mode.
+ * XXX All this happens at the client side.
+ * Returns: 0 = need more data, -1 = wrong cookie, 1 = ok
+ */
+int
+x11_open_helper(Buffer *b)
+{
+ u_char *ucp;
+ u_int proto_len, data_len;
+
+ /* Check if the fixed size part of the packet is in buffer. */
+ if (buffer_len(b) < 12)
+ return 0;
+
+ /* Parse the lengths of variable-length fields. */
+ ucp = (u_char *) buffer_ptr(b);
+ if (ucp[0] == 0x42) { /* Byte order MSB first. */
+ proto_len = 256 * ucp[6] + ucp[7];
+ data_len = 256 * ucp[8] + ucp[9];
+ } else if (ucp[0] == 0x6c) { /* Byte order LSB first. */
+ proto_len = ucp[6] + 256 * ucp[7];
+ data_len = ucp[8] + 256 * ucp[9];
+ } else {
+ debug("Initial X11 packet contains bad byte order byte: 0x%x",
+ ucp[0]);
+ return -1;
+ }
+
+ /* Check if the whole packet is in buffer. */
+ if (buffer_len(b) <
+ 12 + ((proto_len + 3) & ~3) + ((data_len + 3) & ~3))
+ return 0;
+
+ /* Check if authentication protocol matches. */
+ if (proto_len != strlen(x11_saved_proto) ||
+ memcmp(ucp + 12, x11_saved_proto, proto_len) != 0) {
+ debug("X11 connection uses different authentication protocol.");
+ return -1;
+ }
+ /* Check if authentication data matches our fake data. */
+ if (data_len != x11_fake_data_len ||
+ memcmp(ucp + 12 + ((proto_len + 3) & ~3),
+ x11_fake_data, x11_fake_data_len) != 0) {
+ debug("X11 auth data does not match fake data.");
+ return -1;
+ }
+ /* Check fake data length */
+ if (x11_fake_data_len != x11_saved_data_len) {
+ error("X11 fake_data_len %d != saved_data_len %d",
+ x11_fake_data_len, x11_saved_data_len);
+ return -1;
+ }
+ /*
+ * Received authentication protocol and data match
+ * our fake data. Substitute the fake data with real
+ * data.
+ */
+ memcpy(ucp + 12 + ((proto_len + 3) & ~3),
+ x11_saved_data, x11_saved_data_len);
+ return 1;
+}
+
+void
+channel_pre_x11_open_13(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ int ret = x11_open_helper(&c->output);
+ if (ret == 1) {
+ /* Start normal processing for the channel. */
+ c->type = SSH_CHANNEL_OPEN;
+ channel_pre_open_13(c, readset, writeset);
+ } else if (ret == -1) {
+ /*
+ * We have received an X11 connection that has bad
+ * authentication information.
+ */
+ log("X11 connection rejected because of wrong authentication.");
+ buffer_clear(&c->input);
+ buffer_clear(&c->output);
+ close(c->sock);
+ c->sock = -1;
+ c->type = SSH_CHANNEL_CLOSED;
+ packet_start(SSH_MSG_CHANNEL_CLOSE);
+ packet_put_int(c->remote_id);
+ packet_send();
+ }
+}
+
+void
+channel_pre_x11_open(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ int ret = x11_open_helper(&c->output);
+ if (ret == 1) {
+ c->type = SSH_CHANNEL_OPEN;
+ if (compat20)
+ channel_pre_open_20(c, readset, writeset);
+ else
+ channel_pre_open_15(c, readset, writeset);
+ } else if (ret == -1) {
+ debug("X11 rejected %d i%d/o%d", c->self, c->istate, c->ostate);
+ chan_read_failed(c); /** force close? */
+ chan_write_failed(c);
+ debug("X11 closed %d i%d/o%d", c->self, c->istate, c->ostate);
+ }
+}
+
+/* try to decode a socks4 header */
+int
+channel_decode_socks4(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ u_char *p, *host;
+ int len, have, i, found;
+ char username[256];
+ struct {
+ u_int8_t version;
+ u_int8_t command;
+ u_int16_t dest_port;
+ struct in_addr dest_addr;
+ } s4_req, s4_rsp;
+
+ debug2("channel %d: decode socks4", c->self);
+
+ have = buffer_len(&c->input);
+ len = sizeof(s4_req);
+ if (have < len)
+ return 0;
+ p = buffer_ptr(&c->input);
+ for (found = 0, i = len; i < have; i++) {
+ if (p[i] == '\0') {
+ found = 1;
+ break;
+ }
+ if (i > 1024) {
+ /* the peer is probably sending garbage */
+ debug("channel %d: decode socks4: too long",
+ c->self);
+ return -1;
+ }
+ }
+ if (!found)
+ return 0;
+ buffer_get(&c->input, (char *)&s4_req.version, 1);
+ buffer_get(&c->input, (char *)&s4_req.command, 1);
+ buffer_get(&c->input, (char *)&s4_req.dest_port, 2);
+ buffer_get(&c->input, (char *)&s4_req.dest_addr, 4);
+ have = buffer_len(&c->input);
+ p = buffer_ptr(&c->input);
+ len = strlen(p);
+ debug2("channel %d: decode socks4: user %s/%d", c->self, p, len);
+ if (len > have)
+ fatal("channel %d: decode socks4: len %d > have %d",
+ c->self, len, have);
+ strlcpy(username, p, sizeof(username));
+ buffer_consume(&c->input, len);
+ buffer_consume(&c->input, 1); /* trailing '\0' */
+
+ host = inet_ntoa(s4_req.dest_addr);
+ strlcpy(c->path, host, sizeof(c->path));
+ c->host_port = ntohs(s4_req.dest_port);
+
+ debug("channel %d: dynamic request: socks4 host %s port %u command %u",
+ c->self, host, c->host_port, s4_req.command);
+
+ if (s4_req.command != 1) {
+ debug("channel %d: cannot handle: socks4 cn %d",
+ c->self, s4_req.command);
+ return -1;
+ }
+ s4_rsp.version = 0; /* vn: 0 for reply */
+ s4_rsp.command = 90; /* cd: req granted */
+ s4_rsp.dest_port = 0; /* ignored */
+ s4_rsp.dest_addr.s_addr = INADDR_ANY; /* ignored */
+ buffer_append(&c->output, (char *)&s4_rsp, sizeof(s4_rsp));
+ return 1;
+}
+
+/* dynamic port forwarding */
+void
+channel_pre_dynamic(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ u_char *p;
+ int have, ret;
+
+ have = buffer_len(&c->input);
+
+ debug2("channel %d: pre_dynamic: have %d", c->self, have);
+ /* buffer_dump(&c->input); */
+ /* check if the fixed size part of the packet is in buffer. */
+ if (have < 4) {
+ /* need more */
+ FD_SET(c->sock, readset);
+ return;
+ }
+ /* try to guess the protocol */
+ p = buffer_ptr(&c->input);
+ switch (p[0]) {
+ case 0x04:
+ ret = channel_decode_socks4(c, readset, writeset);
+ break;
+ default:
+ ret = -1;
+ break;
+ }
+ if (ret < 0) {
+ chan_mark_dead(c);
+ } else if (ret == 0) {
+ debug2("channel %d: pre_dynamic: need more", c->self);
+ /* need more */
+ FD_SET(c->sock, readset);
+ } else {
+ /* switch to the next state */
+ c->type = SSH_CHANNEL_OPENING;
+ port_open_helper(c, "direct-tcpip");
+ }
+}
+
+/* This is our fake X11 server socket. */
+void
+channel_post_x11_listener(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ Channel *nc;
+ struct sockaddr addr;
+ int newsock;
+ socklen_t addrlen;
+ char buf[16384], *remote_ipaddr;
+ int remote_port;
+
+ if (FD_ISSET(c->sock, readset)) {
+ debug("X11 connection requested.");
+ addrlen = sizeof(addr);
+ newsock = accept(c->sock, &addr, &addrlen);
+ if (newsock < 0) {
+ error("accept: %.100s", strerror(errno));
+ return;
+ }
+ remote_ipaddr = get_peer_ipaddr(newsock);
+ remote_port = get_peer_port(newsock);
+ snprintf(buf, sizeof buf, "X11 connection from %.200s port %d",
+ remote_ipaddr, remote_port);
+
+ nc = channel_new("accepted x11 socket",
+ SSH_CHANNEL_OPENING, newsock, newsock, -1,
+ c->local_window_max, c->local_maxpacket,
+ 0, xstrdup(buf), 1);
+ if (nc == NULL) {
+ close(newsock);
+ xfree(remote_ipaddr);
+ return;
+ }
+ if (compat20) {
+ packet_start(SSH2_MSG_CHANNEL_OPEN);
+ packet_put_cstring("x11");
+ packet_put_int(nc->self);
+ packet_put_int(c->local_window_max);
+ packet_put_int(c->local_maxpacket);
+ /* originator ipaddr and port */
+ packet_put_cstring(remote_ipaddr);
+ if (datafellows & SSH_BUG_X11FWD) {
+ debug("ssh2 x11 bug compat mode");
+ } else {
+ packet_put_int(remote_port);
+ }
+ packet_send();
+ } else {
+ packet_start(SSH_SMSG_X11_OPEN);
+ packet_put_int(nc->self);
+ if (packet_get_protocol_flags() &
+ SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
+ packet_put_string(buf, strlen(buf));
+ packet_send();
+ }
+ xfree(remote_ipaddr);
+ }
+}
+
+void
+port_open_helper(Channel *c, char *rtype)
+{
+ int direct;
+ char buf[1024];
+ char *remote_ipaddr = get_peer_ipaddr(c->sock);
+ u_short remote_port = get_peer_port(c->sock);
+
+ direct = (strcmp(rtype, "direct-tcpip") == 0);
+
+ snprintf(buf, sizeof buf,
+ "%s: listening port %d for %.100s port %d, "
+ "connect from %.200s port %d",
+ rtype, c->listening_port, c->path, c->host_port,
+ remote_ipaddr, remote_port);
+
+ xfree(c->remote_name);
+ c->remote_name = xstrdup(buf);
+
+ if (compat20) {
+ packet_start(SSH2_MSG_CHANNEL_OPEN);
+ packet_put_cstring(rtype);
+ packet_put_int(c->self);
+ packet_put_int(c->local_window_max);
+ packet_put_int(c->local_maxpacket);
+ if (direct) {
+ /* target host, port */
+ packet_put_cstring(c->path);
+ packet_put_int(c->host_port);
+ } else {
+ /* listen address, port */
+ packet_put_cstring(c->path);
+ packet_put_int(c->listening_port);
+ }
+ /* originator host and port */
+ packet_put_cstring(remote_ipaddr);
+ packet_put_int(remote_port);
+ packet_send();
+ } else {
+ packet_start(SSH_MSG_PORT_OPEN);
+ packet_put_int(c->self);
+ packet_put_cstring(c->path);
+ packet_put_int(c->host_port);
+ if (packet_get_protocol_flags() &
+ SSH_PROTOFLAG_HOST_IN_FWD_OPEN)
+ packet_put_cstring(c->remote_name);
+ packet_send();
+ }
+ xfree(remote_ipaddr);
+}
+
+/*
+ * This socket is listening for connections to a forwarded TCP/IP port.
+ */
+void
+channel_post_port_listener(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ Channel *nc;
+ struct sockaddr addr;
+ int newsock, nextstate;
+ socklen_t addrlen;
+ char *rtype;
+
+ if (FD_ISSET(c->sock, readset)) {
+ debug("Connection to port %d forwarding "
+ "to %.100s port %d requested.",
+ c->listening_port, c->path, c->host_port);
+
+ rtype = (c->type == SSH_CHANNEL_RPORT_LISTENER) ?
+ "forwarded-tcpip" : "direct-tcpip";
+ nextstate = (c->host_port == 0 &&
+ c->type != SSH_CHANNEL_RPORT_LISTENER) ?
+ SSH_CHANNEL_DYNAMIC : SSH_CHANNEL_OPENING;
+
+ addrlen = sizeof(addr);
+ newsock = accept(c->sock, &addr, &addrlen);
+ if (newsock < 0) {
+ error("accept: %.100s", strerror(errno));
+ return;
+ }
+ nc = channel_new(rtype,
+ nextstate, newsock, newsock, -1,
+ c->local_window_max, c->local_maxpacket,
+ 0, xstrdup(rtype), 1);
+ if (nc == NULL) {
+ error("channel_post_port_listener: no new channel:");
+ close(newsock);
+ return;
+ }
+ nc->listening_port = c->listening_port;
+ nc->host_port = c->host_port;
+ strlcpy(nc->path, c->path, sizeof(nc->path));
+
+ if (nextstate != SSH_CHANNEL_DYNAMIC)
+ port_open_helper(nc, rtype);
+ }
+}
+
+/*
+ * This is the authentication agent socket listening for connections from
+ * clients.
+ */
+void
+channel_post_auth_listener(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ Channel *nc;
+ char *name;
+ int newsock;
+ struct sockaddr addr;
+ socklen_t addrlen;
+
+ if (FD_ISSET(c->sock, readset)) {
+ addrlen = sizeof(addr);
+ newsock = accept(c->sock, &addr, &addrlen);
+ if (newsock < 0) {
+ error("accept from auth socket: %.100s", strerror(errno));
+ return;
+ }
+ name = xstrdup("accepted auth socket");
+ nc = channel_new("accepted auth socket",
+ SSH_CHANNEL_OPENING, newsock, newsock, -1,
+ c->local_window_max, c->local_maxpacket,
+ 0, name, 1);
+ if (nc == NULL) {
+ error("channel_post_auth_listener: channel_new failed");
+ xfree(name);
+ close(newsock);
+ }
+ if (compat20) {
+ packet_start(SSH2_MSG_CHANNEL_OPEN);
+ packet_put_cstring("auth-agent@openssh.com");
+ packet_put_int(nc->self);
+ packet_put_int(c->local_window_max);
+ packet_put_int(c->local_maxpacket);
+ } else {
+ packet_start(SSH_SMSG_AGENT_OPEN);
+ packet_put_int(nc->self);
+ }
+ packet_send();
+ }
+}
+
+void
+channel_post_connecting(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ int err = 0;
+ int sz = sizeof(err);
+
+ if (FD_ISSET(c->sock, writeset)) {
+ if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, (char *)&err,
+ &sz) < 0) {
+ err = errno;
+ error("getsockopt SO_ERROR failed");
+ }
+ if (err == 0) {
+ debug("channel %d: connected", c->self);
+ c->type = SSH_CHANNEL_OPEN;
+ if (compat20) {
+ packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION);
+ packet_put_int(c->remote_id);
+ packet_put_int(c->self);
+ packet_put_int(c->local_window);
+ packet_put_int(c->local_maxpacket);
+ } else {
+ packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION);
+ packet_put_int(c->remote_id);
+ packet_put_int(c->self);
+ }
+ } else {
+ debug("channel %d: not connected: %s",
+ c->self, strerror(err));
+ if (compat20) {
+ packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE);
+ packet_put_int(c->remote_id);
+ packet_put_int(SSH2_OPEN_CONNECT_FAILED);
+ if (!(datafellows & SSH_BUG_OPENFAILURE)) {
+ packet_put_cstring(strerror(err));
+ packet_put_cstring("");
+ }
+ } else {
+ packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE);
+ packet_put_int(c->remote_id);
+ }
+ chan_mark_dead(c);
+ }
+ packet_send();
+ }
+}
+
+int
+channel_handle_rfd(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ char buf[16*1024];
+ int len;
+
+ if (c->rfd != -1 &&
+ FD_ISSET(c->rfd, readset)) {
+ len = read(c->rfd, buf, sizeof(buf));
+ if (len < 0 && (errno == EINTR || errno == EAGAIN))
+ return 1;
+ if (len <= 0) {
+ debug("channel %d: read<=0 rfd %d len %d",
+ c->self, c->rfd, len);
+ if (c->type != SSH_CHANNEL_OPEN) {
+ debug("channel %d: not open", c->self);
+ chan_mark_dead(c);
+ return -1;
+ } else if (compat13) {
+ buffer_consume(&c->output, buffer_len(&c->output));
+ c->type = SSH_CHANNEL_INPUT_DRAINING;
+ debug("channel %d: input draining.", c->self);
+ } else {
+ chan_read_failed(c);
+ }
+ return -1;
+ }
+ if(c->input_filter != NULL) {
+ if (c->input_filter(c, buf, len) == -1) {
+ debug("channel %d: filter stops", c->self);
+ chan_read_failed(c);
+ }
+ } else {
+ buffer_append(&c->input, buf, len);
+ }
+ }
+ return 1;
+}
+int
+channel_handle_wfd(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ struct termios tio;
+ int len;
+
+ /* Send buffered output data to the socket. */
+ if (c->wfd != -1 &&
+ FD_ISSET(c->wfd, writeset) &&
+ buffer_len(&c->output) > 0) {
+ len = write(c->wfd, buffer_ptr(&c->output),
+ buffer_len(&c->output));
+ if (len < 0 && (errno == EINTR || errno == EAGAIN))
+ return 1;
+ if (len <= 0) {
+ if (c->type != SSH_CHANNEL_OPEN) {
+ debug("channel %d: not open", c->self);
+ chan_mark_dead(c);
+ return -1;
+ } else if (compat13) {
+ buffer_consume(&c->output, buffer_len(&c->output));
+ debug("channel %d: input draining.", c->self);
+ c->type = SSH_CHANNEL_INPUT_DRAINING;
+ } else {
+ chan_write_failed(c);
+ }
+ return -1;
+ }
+ if (compat20 && c->isatty) {
+ if (tcgetattr(c->wfd, &tio) == 0 &&
+ !(tio.c_lflag & ECHO) && (tio.c_lflag & ICANON)) {
+ /*
+ * Simulate echo to reduce the impact of
+ * traffic analysis. We need to match the
+ * size of a SSH2_MSG_CHANNEL_DATA message
+ * (4 byte channel id + data)
+ */
+ packet_send_ignore(4 + len);
+ packet_send();
+ }
+ }
+ buffer_consume(&c->output, len);
+ if (compat20 && len > 0) {
+ c->local_consumed += len;
+ }
+ }
+ return 1;
+}
+int
+channel_handle_efd(Channel *c, fd_set * readset, fd_set * writeset)
+{
+ char buf[16*1024];
+ int len;
+
+/** XXX handle drain efd, too */
+ if (c->efd != -1) {
+ if (c->extended_usage == CHAN_EXTENDED_WRITE &&
+ FD_ISSET(c->efd, writeset) &&
+ buffer_len(&c->extended) > 0) {
+ len = write(c->efd, buffer_ptr(&c->extended),
+ buffer_len(&c->extended));
+ debug2("channel %d: written %d to efd %d",
+ c->self, len, c->efd);
+ if (len < 0 && (errno == EINTR || errno == EAGAIN))
+ return 1;
+ if (len <= 0) {
+ debug2("channel %d: closing write-efd %d",
+ c->self, c->efd);
+ close(c->efd);
+ c->efd = -1;
+ } else {
+ buffer_consume(&c->extended, len);
+ c->local_consumed += len;
+ }
+ } else if (c->extended_usage == CHAN_EXTENDED_READ &&
+ FD_ISSET(c->efd, readset)) {
+ len = read(c->efd, buf, sizeof(buf));
+ debug2("channel %d: read %d from efd %d",
+ c->self, len, c->efd);
+ if (len < 0 && (errno == EINTR || errno == EAGAIN))
+ return 1;
+ if (len <= 0) {
+ debug2("channel %d: closing read-efd %d",
+ c->self, c->efd);
+ close(c->efd);
+ c->efd = -1;
+ } else {
+ buffer_append(&c->extended, buf, len);
+ }