Put ssh back into the repository
Change-Id: I23324372188fa6ed3f93a32b84365f5df6367590
diff --git a/mux.c b/mux.c
new file mode 100644
index 0000000..add0e26
--- /dev/null
+++ b/mux.c
@@ -0,0 +1,2037 @@
+/* $OpenBSD: mux.c,v 1.29 2011/06/22 22:08:42 djm Exp $ */
+/*
+ * Copyright (c) 2002-2008 Damien Miller <djm@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/* ssh session multiplexing support */
+
+/*
+ * TODO:
+ * - Better signalling from master to slave, especially passing of
+ * error messages
+ * - Better fall-back from mux slave error to new connection.
+ * - ExitOnForwardingFailure
+ * - Maybe extension mechanisms for multi-X11/multi-agent forwarding
+ * - Support ~^Z in mux slaves.
+ * - Inspect or control sessions in master.
+ * - If we ever support the "signal" channel request, send signals on
+ * sessions in master.
+ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#ifdef HAVE_PATHS_H
+#include <paths.h>
+#endif
+
+#ifdef HAVE_POLL_H
+#include <poll.h>
+#else
+# ifdef HAVE_SYS_POLL_H
+# include <sys/poll.h>
+# endif
+#endif
+
+#ifdef HAVE_UTIL_H
+# include <util.h>
+#endif
+
+#ifdef HAVE_LIBUTIL_H
+# include <libutil.h>
+#endif
+
+#include "openbsd-compat/sys-queue.h"
+#include "xmalloc.h"
+#include "log.h"
+#include "ssh.h"
+#include "ssh2.h"
+#include "pathnames.h"
+#include "misc.h"
+#include "match.h"
+#include "buffer.h"
+#include "channels.h"
+#include "msg.h"
+#include "packet.h"
+#include "monitor_fdpass.h"
+#include "sshpty.h"
+#include "key.h"
+#include "readconf.h"
+#include "clientloop.h"
+
+/* from ssh.c */
+extern int tty_flag;
+extern Options options;
+extern int stdin_null_flag;
+extern char *host;
+extern int subsystem_flag;
+extern Buffer command;
+extern volatile sig_atomic_t quit_pending;
+extern char *stdio_forward_host;
+extern int stdio_forward_port;
+
+/* Context for session open confirmation callback */
+struct mux_session_confirm_ctx {
+ u_int want_tty;
+ u_int want_subsys;
+ u_int want_x_fwd;
+ u_int want_agent_fwd;
+ Buffer cmd;
+ char *term;
+ struct termios tio;
+ char **env;
+ u_int rid;
+};
+
+/* Context for global channel callback */
+struct mux_channel_confirm_ctx {
+ u_int cid; /* channel id */
+ u_int rid; /* request id */
+ int fid; /* forward id */
+};
+
+/* fd to control socket */
+int muxserver_sock = -1;
+
+/* client request id */
+u_int muxclient_request_id = 0;
+
+/* Multiplexing control command */
+u_int muxclient_command = 0;
+
+/* Set when signalled. */
+static volatile sig_atomic_t muxclient_terminate = 0;
+
+/* PID of multiplex server */
+static u_int muxserver_pid = 0;
+
+static Channel *mux_listener_channel = NULL;
+
+struct mux_master_state {
+ int hello_rcvd;
+};
+
+/* mux protocol messages */
+#define MUX_MSG_HELLO 0x00000001
+#define MUX_C_NEW_SESSION 0x10000002
+#define MUX_C_ALIVE_CHECK 0x10000004
+#define MUX_C_TERMINATE 0x10000005
+#define MUX_C_OPEN_FWD 0x10000006
+#define MUX_C_CLOSE_FWD 0x10000007
+#define MUX_C_NEW_STDIO_FWD 0x10000008
+#define MUX_C_STOP_LISTENING 0x10000009
+#define MUX_S_OK 0x80000001
+#define MUX_S_PERMISSION_DENIED 0x80000002
+#define MUX_S_FAILURE 0x80000003
+#define MUX_S_EXIT_MESSAGE 0x80000004
+#define MUX_S_ALIVE 0x80000005
+#define MUX_S_SESSION_OPENED 0x80000006
+#define MUX_S_REMOTE_PORT 0x80000007
+#define MUX_S_TTY_ALLOC_FAIL 0x80000008
+
+/* type codes for MUX_C_OPEN_FWD and MUX_C_CLOSE_FWD */
+#define MUX_FWD_LOCAL 1
+#define MUX_FWD_REMOTE 2
+#define MUX_FWD_DYNAMIC 3
+
+static void mux_session_confirm(int, int, void *);
+
+static int process_mux_master_hello(u_int, Channel *, Buffer *, Buffer *);
+static int process_mux_new_session(u_int, Channel *, Buffer *, Buffer *);
+static int process_mux_alive_check(u_int, Channel *, Buffer *, Buffer *);
+static int process_mux_terminate(u_int, Channel *, Buffer *, Buffer *);
+static int process_mux_open_fwd(u_int, Channel *, Buffer *, Buffer *);
+static int process_mux_close_fwd(u_int, Channel *, Buffer *, Buffer *);
+static int process_mux_stdio_fwd(u_int, Channel *, Buffer *, Buffer *);
+static int process_mux_stop_listening(u_int, Channel *, Buffer *, Buffer *);
+
+static const struct {
+ u_int type;
+ int (*handler)(u_int, Channel *, Buffer *, Buffer *);
+} mux_master_handlers[] = {
+ { MUX_MSG_HELLO, process_mux_master_hello },
+ { MUX_C_NEW_SESSION, process_mux_new_session },
+ { MUX_C_ALIVE_CHECK, process_mux_alive_check },
+ { MUX_C_TERMINATE, process_mux_terminate },
+ { MUX_C_OPEN_FWD, process_mux_open_fwd },
+ { MUX_C_CLOSE_FWD, process_mux_close_fwd },
+ { MUX_C_NEW_STDIO_FWD, process_mux_stdio_fwd },
+ { MUX_C_STOP_LISTENING, process_mux_stop_listening },
+ { 0, NULL }
+};
+
+/* Cleanup callback fired on closure of mux slave _session_ channel */
+/* ARGSUSED */
+static void
+mux_master_session_cleanup_cb(int cid, void *unused)
+{
+ Channel *cc, *c = channel_by_id(cid);
+
+ debug3("%s: entering for channel %d", __func__, cid);
+ if (c == NULL)
+ fatal("%s: channel_by_id(%i) == NULL", __func__, cid);
+ if (c->ctl_chan != -1) {
+ if ((cc = channel_by_id(c->ctl_chan)) == NULL)
+ fatal("%s: channel %d missing control channel %d",
+ __func__, c->self, c->ctl_chan);
+ c->ctl_chan = -1;
+ cc->remote_id = -1;
+ chan_rcvd_oclose(cc);
+ }
+ channel_cancel_cleanup(c->self);
+}
+
+/* Cleanup callback fired on closure of mux slave _control_ channel */
+/* ARGSUSED */
+static void
+mux_master_control_cleanup_cb(int cid, void *unused)
+{
+ Channel *sc, *c = channel_by_id(cid);
+
+ debug3("%s: entering for channel %d", __func__, cid);
+ if (c == NULL)
+ fatal("%s: channel_by_id(%i) == NULL", __func__, cid);
+ if (c->remote_id != -1) {
+ if ((sc = channel_by_id(c->remote_id)) == NULL)
+ fatal("%s: channel %d missing session channel %d",
+ __func__, c->self, c->remote_id);
+ c->remote_id = -1;
+ sc->ctl_chan = -1;
+ if (sc->type != SSH_CHANNEL_OPEN) {
+ debug2("%s: channel %d: not open", __func__, sc->self);
+ chan_mark_dead(sc);
+ } else {
+ if (sc->istate == CHAN_INPUT_OPEN)
+ chan_read_failed(sc);
+ if (sc->ostate == CHAN_OUTPUT_OPEN)
+ chan_write_failed(sc);
+ }
+ }
+ channel_cancel_cleanup(c->self);
+}
+
+/* Check mux client environment variables before passing them to mux master. */
+static int
+env_permitted(char *env)
+{
+ int i, ret;
+ char name[1024], *cp;
+
+ if ((cp = strchr(env, '=')) == NULL || cp == env)
+ return 0;
+ ret = snprintf(name, sizeof(name), "%.*s", (int)(cp - env), env);
+ if (ret <= 0 || (size_t)ret >= sizeof(name)) {
+ error("env_permitted: name '%.100s...' too long", env);
+ return 0;
+ }
+
+ for (i = 0; i < options.num_send_env; i++)
+ if (match_pattern(name, options.send_env[i]))
+ return 1;
+
+ return 0;
+}
+
+/* Mux master protocol message handlers */
+
+static int
+process_mux_master_hello(u_int rid, Channel *c, Buffer *m, Buffer *r)
+{
+ u_int ver;
+ struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx;
+
+ if (state == NULL)
+ fatal("%s: channel %d: c->mux_ctx == NULL", __func__, c->self);
+ if (state->hello_rcvd) {
+ error("%s: HELLO received twice", __func__);
+ return -1;
+ }
+ if (buffer_get_int_ret(&ver, m) != 0) {
+ malf:
+ error("%s: malformed message", __func__);
+ return -1;
+ }
+ if (ver != SSHMUX_VER) {
+ error("Unsupported multiplexing protocol version %d "
+ "(expected %d)", ver, SSHMUX_VER);
+ return -1;
+ }
+ debug2("%s: channel %d slave version %u", __func__, c->self, ver);
+
+ /* No extensions are presently defined */
+ while (buffer_len(m) > 0) {
+ char *name = buffer_get_string_ret(m, NULL);
+ char *value = buffer_get_string_ret(m, NULL);
+
+ if (name == NULL || value == NULL) {
+ if (name != NULL)
+ xfree(name);
+ goto malf;
+ }
+ debug2("Unrecognised slave extension \"%s\"", name);
+ xfree(name);
+ xfree(value);
+ }
+ state->hello_rcvd = 1;
+ return 0;
+}
+
+static int
+process_mux_new_session(u_int rid, Channel *c, Buffer *m, Buffer *r)
+{
+ Channel *nc;
+ struct mux_session_confirm_ctx *cctx;
+ char *reserved, *cmd, *cp;
+ u_int i, j, len, env_len, escape_char, window, packetmax;
+ int new_fd[3];
+
+ /* Reply for SSHMUX_COMMAND_OPEN */
+ cctx = xcalloc(1, sizeof(*cctx));
+ cctx->term = NULL;
+ cctx->rid = rid;
+ cmd = reserved = NULL;
+ if ((reserved = buffer_get_string_ret(m, NULL)) == NULL ||
+ buffer_get_int_ret(&cctx->want_tty, m) != 0 ||
+ buffer_get_int_ret(&cctx->want_x_fwd, m) != 0 ||
+ buffer_get_int_ret(&cctx->want_agent_fwd, m) != 0 ||
+ buffer_get_int_ret(&cctx->want_subsys, m) != 0 ||
+ buffer_get_int_ret(&escape_char, m) != 0 ||
+ (cctx->term = buffer_get_string_ret(m, &len)) == NULL ||
+ (cmd = buffer_get_string_ret(m, &len)) == NULL) {
+ malf:
+ if (cmd != NULL)
+ xfree(cmd);
+ if (reserved != NULL)
+ xfree(reserved);
+ if (cctx->term != NULL)
+ xfree(cctx->term);
+ error("%s: malformed message", __func__);
+ return -1;
+ }
+ xfree(reserved);
+ reserved = NULL;
+
+ cctx->env = NULL;
+ env_len = 0;
+ while (buffer_len(m) > 0) {
+#define MUX_MAX_ENV_VARS 4096
+ if ((cp = buffer_get_string_ret(m, &len)) == NULL) {
+ xfree(cmd);
+ goto malf;
+ }
+ if (!env_permitted(cp)) {
+ xfree(cp);
+ continue;
+ }
+ cctx->env = xrealloc(cctx->env, env_len + 2,
+ sizeof(*cctx->env));
+ cctx->env[env_len++] = cp;
+ cctx->env[env_len] = NULL;
+ if (env_len > MUX_MAX_ENV_VARS) {
+ error(">%d environment variables received, ignoring "
+ "additional", MUX_MAX_ENV_VARS);
+ break;
+ }
+ }
+
+ debug2("%s: channel %d: request tty %d, X %d, agent %d, subsys %d, "
+ "term \"%s\", cmd \"%s\", env %u", __func__, c->self,
+ cctx->want_tty, cctx->want_x_fwd, cctx->want_agent_fwd,
+ cctx->want_subsys, cctx->term, cmd, env_len);
+
+ buffer_init(&cctx->cmd);
+ buffer_append(&cctx->cmd, cmd, strlen(cmd));
+ xfree(cmd);
+ cmd = NULL;
+
+ /* Gather fds from client */
+ for(i = 0; i < 3; i++) {
+ if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) {
+ error("%s: failed to receive fd %d from slave",
+ __func__, i);
+ for (j = 0; j < i; j++)
+ close(new_fd[j]);
+ for (j = 0; j < env_len; j++)
+ xfree(cctx->env[j]);
+ if (env_len > 0)
+ xfree(cctx->env);
+ xfree(cctx->term);
+ buffer_free(&cctx->cmd);
+ xfree(cctx);
+
+ /* prepare reply */
+ buffer_put_int(r, MUX_S_FAILURE);
+ buffer_put_int(r, rid);
+ buffer_put_cstring(r,
+ "did not receive file descriptors");
+ return -1;
+ }
+ }
+
+ debug3("%s: got fds stdin %d, stdout %d, stderr %d", __func__,
+ new_fd[0], new_fd[1], new_fd[2]);
+
+ /* XXX support multiple child sessions in future */
+ if (c->remote_id != -1) {
+ debug2("%s: session already open", __func__);
+ /* prepare reply */
+ buffer_put_int(r, MUX_S_FAILURE);
+ buffer_put_int(r, rid);
+ buffer_put_cstring(r, "Multiple sessions not supported");
+ cleanup:
+ close(new_fd[0]);
+ close(new_fd[1]);
+ close(new_fd[2]);
+ xfree(cctx->term);
+ if (env_len != 0) {
+ for (i = 0; i < env_len; i++)
+ xfree(cctx->env[i]);
+ xfree(cctx->env);
+ }
+ buffer_free(&cctx->cmd);
+ return 0;
+ }
+
+ if (options.control_master == SSHCTL_MASTER_ASK ||
+ options.control_master == SSHCTL_MASTER_AUTO_ASK) {
+ if (!ask_permission("Allow shared connection to %s? ", host)) {
+ debug2("%s: session refused by user", __func__);
+ /* prepare reply */
+ buffer_put_int(r, MUX_S_PERMISSION_DENIED);
+ buffer_put_int(r, rid);
+ buffer_put_cstring(r, "Permission denied");
+ goto cleanup;
+ }
+ }
+
+ /* Try to pick up ttymodes from client before it goes raw */
+ if (cctx->want_tty && tcgetattr(new_fd[0], &cctx->tio) == -1)
+ error("%s: tcgetattr: %s", __func__, strerror(errno));
+
+ /* enable nonblocking unless tty */
+ if (!isatty(new_fd[0]))
+ set_nonblock(new_fd[0]);
+ if (!isatty(new_fd[1]))
+ set_nonblock(new_fd[1]);
+ if (!isatty(new_fd[2]))
+ set_nonblock(new_fd[2]);
+
+ window = CHAN_SES_WINDOW_DEFAULT;
+ packetmax = CHAN_SES_PACKET_DEFAULT;
+ if (cctx->want_tty) {
+ window >>= 1;
+ packetmax >>= 1;
+ }
+
+ nc = channel_new("session", SSH_CHANNEL_OPENING,
+ new_fd[0], new_fd[1], new_fd[2], window, packetmax,
+ CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0);
+
+ nc->ctl_chan = c->self; /* link session -> control channel */
+ c->remote_id = nc->self; /* link control -> session channel */
+
+ if (cctx->want_tty && escape_char != 0xffffffff) {
+ channel_register_filter(nc->self,
+ client_simple_escape_filter, NULL,
+ client_filter_cleanup,
+ client_new_escape_filter_ctx((int)escape_char));
+ }
+
+ debug2("%s: channel_new: %d linked to control channel %d",
+ __func__, nc->self, nc->ctl_chan);
+
+ channel_send_open(nc->self);
+ channel_register_open_confirm(nc->self, mux_session_confirm, cctx);
+ c->mux_pause = 1; /* stop handling messages until open_confirm done */
+ channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1);
+
+ /* reply is deferred, sent by mux_session_confirm */
+ return 0;
+}
+
+static int
+process_mux_alive_check(u_int rid, Channel *c, Buffer *m, Buffer *r)
+{
+ debug2("%s: channel %d: alive check", __func__, c->self);
+
+ /* prepare reply */
+ buffer_put_int(r, MUX_S_ALIVE);
+ buffer_put_int(r, rid);
+ buffer_put_int(r, (u_int)getpid());
+
+ return 0;
+}
+
+static int
+process_mux_terminate(u_int rid, Channel *c, Buffer *m, Buffer *r)
+{
+ debug2("%s: channel %d: terminate request", __func__, c->self);
+
+ if (options.control_master == SSHCTL_MASTER_ASK ||
+ options.control_master == SSHCTL_MASTER_AUTO_ASK) {
+ if (!ask_permission("Terminate shared connection to %s? ",
+ host)) {
+ debug2("%s: termination refused by user", __func__);
+ buffer_put_int(r, MUX_S_PERMISSION_DENIED);
+ buffer_put_int(r, rid);
+ buffer_put_cstring(r, "Permission denied");
+ return 0;
+ }
+ }
+
+ quit_pending = 1;
+ buffer_put_int(r, MUX_S_OK);
+ buffer_put_int(r, rid);
+ /* XXX exit happens too soon - message never makes it to client */
+ return 0;
+}
+
+static char *
+format_forward(u_int ftype, Forward *fwd)
+{
+ char *ret;
+
+ switch (ftype) {
+ case MUX_FWD_LOCAL:
+ xasprintf(&ret, "local forward %.200s:%d -> %.200s:%d",
+ (fwd->listen_host == NULL) ?
+ (options.gateway_ports ? "*" : "LOCALHOST") :
+ fwd->listen_host, fwd->listen_port,
+ fwd->connect_host, fwd->connect_port);
+ break;
+ case MUX_FWD_DYNAMIC:
+ xasprintf(&ret, "dynamic forward %.200s:%d -> *",
+ (fwd->listen_host == NULL) ?
+ (options.gateway_ports ? "*" : "LOCALHOST") :
+ fwd->listen_host, fwd->listen_port);
+ break;
+ case MUX_FWD_REMOTE:
+ xasprintf(&ret, "remote forward %.200s:%d -> %.200s:%d",
+ (fwd->listen_host == NULL) ?
+ "LOCALHOST" : fwd->listen_host,
+ fwd->listen_port,
+ fwd->connect_host, fwd->connect_port);
+ break;
+ default:
+ fatal("%s: unknown forward type %u", __func__, ftype);
+ }
+ return ret;
+}
+
+static int
+compare_host(const char *a, const char *b)
+{
+ if (a == NULL && b == NULL)
+ return 1;
+ if (a == NULL || b == NULL)
+ return 0;
+ return strcmp(a, b) == 0;
+}
+
+static int
+compare_forward(Forward *a, Forward *b)
+{
+ if (!compare_host(a->listen_host, b->listen_host))
+ return 0;
+ if (a->listen_port != b->listen_port)
+ return 0;
+ if (!compare_host(a->connect_host, b->connect_host))
+ return 0;
+ if (a->connect_port != b->connect_port)
+ return 0;
+
+ return 1;
+}
+
+static void
+mux_confirm_remote_forward(int type, u_int32_t seq, void *ctxt)
+{
+ struct mux_channel_confirm_ctx *fctx = ctxt;
+ char *failmsg = NULL;
+ Forward *rfwd;
+ Channel *c;
+ Buffer out;
+
+ if ((c = channel_by_id(fctx->cid)) == NULL) {
+ /* no channel for reply */
+ error("%s: unknown channel", __func__);
+ return;
+ }
+ buffer_init(&out);
+ if (fctx->fid >= options.num_remote_forwards) {
+ xasprintf(&failmsg, "unknown forwarding id %d", fctx->fid);
+ goto fail;
+ }
+ rfwd = &options.remote_forwards[fctx->fid];
+ debug("%s: %s for: listen %d, connect %s:%d", __func__,
+ type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
+ rfwd->listen_port, rfwd->connect_host, rfwd->connect_port);
+ if (type == SSH2_MSG_REQUEST_SUCCESS) {
+ if (rfwd->listen_port == 0) {
+ rfwd->allocated_port = packet_get_int();
+ logit("Allocated port %u for mux remote forward"
+ " to %s:%d", rfwd->allocated_port,
+ rfwd->connect_host, rfwd->connect_port);
+ buffer_put_int(&out, MUX_S_REMOTE_PORT);
+ buffer_put_int(&out, fctx->rid);
+ buffer_put_int(&out, rfwd->allocated_port);
+ } else {
+ buffer_put_int(&out, MUX_S_OK);
+ buffer_put_int(&out, fctx->rid);
+ }
+ goto out;
+ } else {
+ xasprintf(&failmsg, "remote port forwarding failed for "
+ "listen port %d", rfwd->listen_port);
+ }
+ fail:
+ error("%s: %s", __func__, failmsg);
+ buffer_put_int(&out, MUX_S_FAILURE);
+ buffer_put_int(&out, fctx->rid);
+ buffer_put_cstring(&out, failmsg);
+ xfree(failmsg);
+ out:
+ buffer_put_string(&c->output, buffer_ptr(&out), buffer_len(&out));
+ buffer_free(&out);
+ if (c->mux_pause <= 0)
+ fatal("%s: mux_pause %d", __func__, c->mux_pause);
+ c->mux_pause = 0; /* start processing messages again */
+}
+
+static int
+process_mux_open_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
+{
+ Forward fwd;
+ char *fwd_desc = NULL;
+ u_int ftype;
+ int i, ret = 0, freefwd = 1;
+
+ fwd.listen_host = fwd.connect_host = NULL;
+ if (buffer_get_int_ret(&ftype, m) != 0 ||
+ (fwd.listen_host = buffer_get_string_ret(m, NULL)) == NULL ||
+ buffer_get_int_ret(&fwd.listen_port, m) != 0 ||
+ (fwd.connect_host = buffer_get_string_ret(m, NULL)) == NULL ||
+ buffer_get_int_ret(&fwd.connect_port, m) != 0) {
+ error("%s: malformed message", __func__);
+ ret = -1;
+ goto out;
+ }
+
+ if (*fwd.listen_host == '\0') {
+ xfree(fwd.listen_host);
+ fwd.listen_host = NULL;
+ }
+ if (*fwd.connect_host == '\0') {
+ xfree(fwd.connect_host);
+ fwd.connect_host = NULL;
+ }
+
+ debug2("%s: channel %d: request %s", __func__, c->self,
+ (fwd_desc = format_forward(ftype, &fwd)));
+
+ if (ftype != MUX_FWD_LOCAL && ftype != MUX_FWD_REMOTE &&
+ ftype != MUX_FWD_DYNAMIC) {
+ logit("%s: invalid forwarding type %u", __func__, ftype);
+ invalid:
+ if (fwd.listen_host)
+ xfree(fwd.listen_host);
+ if (fwd.connect_host)
+ xfree(fwd.connect_host);
+ buffer_put_int(r, MUX_S_FAILURE);
+ buffer_put_int(r, rid);
+ buffer_put_cstring(r, "Invalid forwarding request");
+ return 0;
+ }
+ if (fwd.listen_port >= 65536) {
+ logit("%s: invalid listen port %u", __func__,
+ fwd.listen_port);
+ goto invalid;
+ }
+ if (fwd.connect_port >= 65536 || (ftype != MUX_FWD_DYNAMIC &&
+ ftype != MUX_FWD_REMOTE && fwd.connect_port == 0)) {
+ logit("%s: invalid connect port %u", __func__,
+ fwd.connect_port);
+ goto invalid;
+ }
+ if (ftype != MUX_FWD_DYNAMIC && fwd.connect_host == NULL) {
+ logit("%s: missing connect host", __func__);
+ goto invalid;
+ }
+
+ /* Skip forwards that have already been requested */
+ switch (ftype) {
+ case MUX_FWD_LOCAL:
+ case MUX_FWD_DYNAMIC:
+ for (i = 0; i < options.num_local_forwards; i++) {
+ if (compare_forward(&fwd,
+ options.local_forwards + i)) {
+ exists:
+ debug2("%s: found existing forwarding",
+ __func__);
+ buffer_put_int(r, MUX_S_OK);
+ buffer_put_int(r, rid);
+ goto out;
+ }
+ }
+ break;
+ case MUX_FWD_REMOTE:
+ for (i = 0; i < options.num_remote_forwards; i++) {
+ if (compare_forward(&fwd,
+ options.remote_forwards + i)) {
+ if (fwd.listen_port != 0)
+ goto exists;
+ debug2("%s: found allocated port",
+ __func__);
+ buffer_put_int(r, MUX_S_REMOTE_PORT);
+ buffer_put_int(r, rid);
+ buffer_put_int(r,
+ options.remote_forwards[i].allocated_port);
+ goto out;
+ }
+ }
+ break;
+ }
+
+ if (options.control_master == SSHCTL_MASTER_ASK ||
+ options.control_master == SSHCTL_MASTER_AUTO_ASK) {
+ if (!ask_permission("Open %s on %s?", fwd_desc, host)) {
+ debug2("%s: forwarding refused by user", __func__);
+ buffer_put_int(r, MUX_S_PERMISSION_DENIED);
+ buffer_put_int(r, rid);
+ buffer_put_cstring(r, "Permission denied");
+ goto out;
+ }
+ }
+
+ if (ftype == MUX_FWD_LOCAL || ftype == MUX_FWD_DYNAMIC) {
+ if (channel_setup_local_fwd_listener(fwd.listen_host,
+ fwd.listen_port, fwd.connect_host, fwd.connect_port,
+ options.gateway_ports) < 0) {
+ fail:
+ logit("slave-requested %s failed", fwd_desc);
+ buffer_put_int(r, MUX_S_FAILURE);
+ buffer_put_int(r, rid);
+ buffer_put_cstring(r, "Port forwarding failed");
+ goto out;
+ }
+ add_local_forward(&options, &fwd);
+ freefwd = 0;
+ } else {
+ struct mux_channel_confirm_ctx *fctx;
+
+ if (channel_request_remote_forwarding(fwd.listen_host,
+ fwd.listen_port, fwd.connect_host, fwd.connect_port) < 0)
+ goto fail;
+ add_remote_forward(&options, &fwd);
+ fctx = xcalloc(1, sizeof(*fctx));
+ fctx->cid = c->self;
+ fctx->rid = rid;
+ fctx->fid = options.num_remote_forwards - 1;
+ client_register_global_confirm(mux_confirm_remote_forward,
+ fctx);
+ freefwd = 0;
+ c->mux_pause = 1; /* wait for mux_confirm_remote_forward */
+ /* delayed reply in mux_confirm_remote_forward */
+ goto out;
+ }
+ buffer_put_int(r, MUX_S_OK);
+ buffer_put_int(r, rid);
+ out:
+ if (fwd_desc != NULL)
+ xfree(fwd_desc);
+ if (freefwd) {
+ if (fwd.listen_host != NULL)
+ xfree(fwd.listen_host);
+ if (fwd.connect_host != NULL)
+ xfree(fwd.connect_host);
+ }
+ return ret;
+}
+
+static int
+process_mux_close_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
+{
+ Forward fwd;
+ char *fwd_desc = NULL;
+ u_int ftype;
+ int ret = 0;
+
+ fwd.listen_host = fwd.connect_host = NULL;
+ if (buffer_get_int_ret(&ftype, m) != 0 ||
+ (fwd.listen_host = buffer_get_string_ret(m, NULL)) == NULL ||
+ buffer_get_int_ret(&fwd.listen_port, m) != 0 ||
+ (fwd.connect_host = buffer_get_string_ret(m, NULL)) == NULL ||
+ buffer_get_int_ret(&fwd.connect_port, m) != 0) {
+ error("%s: malformed message", __func__);
+ ret = -1;
+ goto out;
+ }
+
+ if (*fwd.listen_host == '\0') {
+ xfree(fwd.listen_host);
+ fwd.listen_host = NULL;
+ }
+ if (*fwd.connect_host == '\0') {
+ xfree(fwd.connect_host);
+ fwd.connect_host = NULL;
+ }
+
+ debug2("%s: channel %d: request %s", __func__, c->self,
+ (fwd_desc = format_forward(ftype, &fwd)));
+
+ /* XXX implement this */
+ buffer_put_int(r, MUX_S_FAILURE);
+ buffer_put_int(r, rid);
+ buffer_put_cstring(r, "unimplemented");
+
+ out:
+ if (fwd_desc != NULL)
+ xfree(fwd_desc);
+ if (fwd.listen_host != NULL)
+ xfree(fwd.listen_host);
+ if (fwd.connect_host != NULL)
+ xfree(fwd.connect_host);
+
+ return ret;
+}
+
+static int
+process_mux_stdio_fwd(u_int rid, Channel *c, Buffer *m, Buffer *r)
+{
+ Channel *nc;
+ char *reserved, *chost;
+ u_int cport, i, j;
+ int new_fd[2];
+
+ chost = reserved = NULL;
+ if ((reserved = buffer_get_string_ret(m, NULL)) == NULL ||
+ (chost = buffer_get_string_ret(m, NULL)) == NULL ||
+ buffer_get_int_ret(&cport, m) != 0) {
+ if (reserved != NULL)
+ xfree(reserved);
+ if (chost != NULL)
+ xfree(chost);
+ error("%s: malformed message", __func__);
+ return -1;
+ }
+ xfree(reserved);
+
+ debug2("%s: channel %d: request stdio fwd to %s:%u",
+ __func__, c->self, chost, cport);
+
+ /* Gather fds from client */
+ for(i = 0; i < 2; i++) {
+ if ((new_fd[i] = mm_receive_fd(c->sock)) == -1) {
+ error("%s: failed to receive fd %d from slave",
+ __func__, i);
+ for (j = 0; j < i; j++)
+ close(new_fd[j]);
+ xfree(chost);
+
+ /* prepare reply */
+ buffer_put_int(r, MUX_S_FAILURE);
+ buffer_put_int(r, rid);
+ buffer_put_cstring(r,
+ "did not receive file descriptors");
+ return -1;
+ }
+ }
+
+ debug3("%s: got fds stdin %d, stdout %d", __func__,
+ new_fd[0], new_fd[1]);
+
+ /* XXX support multiple child sessions in future */
+ if (c->remote_id != -1) {
+ debug2("%s: session already open", __func__);
+ /* prepare reply */
+ buffer_put_int(r, MUX_S_FAILURE);
+ buffer_put_int(r, rid);
+ buffer_put_cstring(r, "Multiple sessions not supported");
+ cleanup:
+ close(new_fd[0]);
+ close(new_fd[1]);
+ xfree(chost);
+ return 0;
+ }
+
+ if (options.control_master == SSHCTL_MASTER_ASK ||
+ options.control_master == SSHCTL_MASTER_AUTO_ASK) {
+ if (!ask_permission("Allow forward to %s:%u? ",
+ chost, cport)) {
+ debug2("%s: stdio fwd refused by user", __func__);
+ /* prepare reply */
+ buffer_put_int(r, MUX_S_PERMISSION_DENIED);
+ buffer_put_int(r, rid);
+ buffer_put_cstring(r, "Permission denied");
+ goto cleanup;
+ }
+ }
+
+ /* enable nonblocking unless tty */
+ if (!isatty(new_fd[0]))
+ set_nonblock(new_fd[0]);
+ if (!isatty(new_fd[1]))
+ set_nonblock(new_fd[1]);
+
+ nc = channel_connect_stdio_fwd(chost, cport, new_fd[0], new_fd[1]);
+
+ nc->ctl_chan = c->self; /* link session -> control channel */
+ c->remote_id = nc->self; /* link control -> session channel */
+
+ debug2("%s: channel_new: %d linked to control channel %d",
+ __func__, nc->self, nc->ctl_chan);
+
+ channel_register_cleanup(nc->self, mux_master_session_cleanup_cb, 1);
+
+ /* prepare reply */
+ /* XXX defer until channel confirmed */
+ buffer_put_int(r, MUX_S_SESSION_OPENED);
+ buffer_put_int(r, rid);
+ buffer_put_int(r, nc->self);
+
+ return 0;
+}
+
+static int
+process_mux_stop_listening(u_int rid, Channel *c, Buffer *m, Buffer *r)
+{
+ debug("%s: channel %d: stop listening", __func__, c->self);
+
+ if (options.control_master == SSHCTL_MASTER_ASK ||
+ options.control_master == SSHCTL_MASTER_AUTO_ASK) {
+ if (!ask_permission("Disable further multiplexing on shared "
+ "connection to %s? ", host)) {
+ debug2("%s: stop listen refused by user", __func__);
+ buffer_put_int(r, MUX_S_PERMISSION_DENIED);
+ buffer_put_int(r, rid);
+ buffer_put_cstring(r, "Permission denied");
+ return 0;
+ }
+ }
+
+ if (mux_listener_channel != NULL) {
+ channel_free(mux_listener_channel);
+ client_stop_mux();
+ xfree(options.control_path);
+ options.control_path = NULL;
+ mux_listener_channel = NULL;
+ muxserver_sock = -1;
+ }
+
+ /* prepare reply */
+ buffer_put_int(r, MUX_S_OK);
+ buffer_put_int(r, rid);
+
+ return 0;
+}
+
+/* Channel callbacks fired on read/write from mux slave fd */
+static int
+mux_master_read_cb(Channel *c)
+{
+ struct mux_master_state *state = (struct mux_master_state *)c->mux_ctx;
+ Buffer in, out;
+ void *ptr;
+ u_int type, rid, have, i;
+ int ret = -1;
+
+ /* Setup ctx and */
+ if (c->mux_ctx == NULL) {
+ state = xcalloc(1, sizeof(*state));
+ c->mux_ctx = state;
+ channel_register_cleanup(c->self,
+ mux_master_control_cleanup_cb, 0);
+
+ /* Send hello */
+ buffer_init(&out);
+ buffer_put_int(&out, MUX_MSG_HELLO);
+ buffer_put_int(&out, SSHMUX_VER);
+ /* no extensions */
+ buffer_put_string(&c->output, buffer_ptr(&out),
+ buffer_len(&out));
+ buffer_free(&out);
+ debug3("%s: channel %d: hello sent", __func__, c->self);
+ return 0;
+ }
+
+ buffer_init(&in);
+ buffer_init(&out);
+
+ /* Channel code ensures that we receive whole packets */
+ if ((ptr = buffer_get_string_ptr_ret(&c->input, &have)) == NULL) {
+ malf:
+ error("%s: malformed message", __func__);
+ goto out;
+ }
+ buffer_append(&in, ptr, have);
+
+ if (buffer_get_int_ret(&type, &in) != 0)
+ goto malf;
+ debug3("%s: channel %d packet type 0x%08x len %u",
+ __func__, c->self, type, buffer_len(&in));
+
+ if (type == MUX_MSG_HELLO)
+ rid = 0;
+ else {
+ if (!state->hello_rcvd) {
+ error("%s: expected MUX_MSG_HELLO(0x%08x), "
+ "received 0x%08x", __func__, MUX_MSG_HELLO, type);
+ goto out;
+ }
+ if (buffer_get_int_ret(&rid, &in) != 0)
+ goto malf;
+ }
+
+ for (i = 0; mux_master_handlers[i].handler != NULL; i++) {
+ if (type == mux_master_handlers[i].type) {
+ ret = mux_master_handlers[i].handler(rid, c, &in, &out);
+ break;
+ }
+ }
+ if (mux_master_handlers[i].handler == NULL) {
+ error("%s: unsupported mux message 0x%08x", __func__, type);
+ buffer_put_int(&out, MUX_S_FAILURE);
+ buffer_put_int(&out, rid);
+ buffer_put_cstring(&out, "unsupported request");
+ ret = 0;
+ }
+ /* Enqueue reply packet */
+ if (buffer_len(&out) != 0) {
+ buffer_put_string(&c->output, buffer_ptr(&out),
+ buffer_len(&out));
+ }
+ out:
+ buffer_free(&in);
+ buffer_free(&out);
+ return ret;
+}
+
+void
+mux_exit_message(Channel *c, int exitval)
+{
+ Buffer m;
+ Channel *mux_chan;
+
+ debug3("%s: channel %d: exit message, evitval %d", __func__, c->self,
+ exitval);
+
+ if ((mux_chan = channel_by_id(c->ctl_chan)) == NULL)
+ fatal("%s: channel %d missing mux channel %d",
+ __func__, c->self, c->ctl_chan);
+
+ /* Append exit message packet to control socket output queue */
+ buffer_init(&m);
+ buffer_put_int(&m, MUX_S_EXIT_MESSAGE);
+ buffer_put_int(&m, c->self);
+ buffer_put_int(&m, exitval);
+
+ buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m));
+ buffer_free(&m);
+}
+
+void
+mux_tty_alloc_failed(Channel *c)
+{
+ Buffer m;
+ Channel *mux_chan;
+
+ debug3("%s: channel %d: TTY alloc failed", __func__, c->self);
+
+ if ((mux_chan = channel_by_id(c->ctl_chan)) == NULL)
+ fatal("%s: channel %d missing mux channel %d",
+ __func__, c->self, c->ctl_chan);
+
+ /* Append exit message packet to control socket output queue */
+ buffer_init(&m);
+ buffer_put_int(&m, MUX_S_TTY_ALLOC_FAIL);
+ buffer_put_int(&m, c->self);
+
+ buffer_put_string(&mux_chan->output, buffer_ptr(&m), buffer_len(&m));
+ buffer_free(&m);
+}
+
+/* Prepare a mux master to listen on a Unix domain socket. */
+void
+muxserver_listen(void)
+{
+ struct sockaddr_un addr;
+ socklen_t sun_len;
+ mode_t old_umask;
+ char *orig_control_path = options.control_path;
+ char rbuf[16+1];
+ u_int i, r;
+
+ if (options.control_path == NULL ||
+ options.control_master == SSHCTL_MASTER_NO)
+ return;
+
+ debug("setting up multiplex master socket");
+
+ /*
+ * Use a temporary path before listen so we can pseudo-atomically
+ * establish the listening socket in its final location to avoid
+ * other processes racing in between bind() and listen() and hitting
+ * an unready socket.
+ */
+ for (i = 0; i < sizeof(rbuf) - 1; i++) {
+ r = arc4random_uniform(26+26+10);
+ rbuf[i] = (r < 26) ? 'a' + r :
+ (r < 26*2) ? 'A' + r - 26 :
+ '0' + r - 26 - 26;
+ }
+ rbuf[sizeof(rbuf) - 1] = '\0';
+ options.control_path = NULL;
+ xasprintf(&options.control_path, "%s.%s", orig_control_path, rbuf);
+ debug3("%s: temporary control path %s", __func__, options.control_path);
+
+ memset(&addr, '\0', sizeof(addr));
+ addr.sun_family = AF_UNIX;
+ sun_len = offsetof(struct sockaddr_un, sun_path) +
+ strlen(options.control_path) + 1;
+
+ if (strlcpy(addr.sun_path, options.control_path,
+ sizeof(addr.sun_path)) >= sizeof(addr.sun_path)) {
+ error("ControlPath \"%s\" too long for Unix domain socket",
+ options.control_path);
+ goto disable_mux_master;
+ }
+
+ if ((muxserver_sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
+ fatal("%s socket(): %s", __func__, strerror(errno));
+
+ old_umask = umask(0177);
+ if (bind(muxserver_sock, (struct sockaddr *)&addr, sun_len) == -1) {
+ if (errno == EINVAL || errno == EADDRINUSE) {
+ error("ControlSocket %s already exists, "
+ "disabling multiplexing", options.control_path);
+ disable_mux_master:
+ if (muxserver_sock != -1) {
+ close(muxserver_sock);
+ muxserver_sock = -1;
+ }
+ xfree(options.control_path);
+ options.control_path = NULL;
+ options.control_master = SSHCTL_MASTER_NO;
+ return;
+ } else
+ fatal("%s bind(): %s", __func__, strerror(errno));
+ }
+ umask(old_umask);
+
+ if (listen(muxserver_sock, 64) == -1)
+ fatal("%s listen(): %s", __func__, strerror(errno));
+
+ /* Now atomically "move" the mux socket into position */
+ if (link(options.control_path, orig_control_path) != 0) {
+ if (errno != EEXIST) {
+ fatal("%s: link mux listener %s => %s: %s", __func__,
+ options.control_path, orig_control_path,
+ strerror(errno));
+ }
+ error("ControlSocket %s already exists, disabling multiplexing",
+ orig_control_path);
+ xfree(orig_control_path);
+ unlink(options.control_path);
+ goto disable_mux_master;
+ }
+ unlink(options.control_path);
+ xfree(options.control_path);
+ options.control_path = orig_control_path;
+
+ set_nonblock(muxserver_sock);
+
+ mux_listener_channel = channel_new("mux listener",
+ SSH_CHANNEL_MUX_LISTENER, muxserver_sock, muxserver_sock, -1,
+ CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT,
+ 0, options.control_path, 1);
+ mux_listener_channel->mux_rcb = mux_master_read_cb;
+ debug3("%s: mux listener channel %d fd %d", __func__,
+ mux_listener_channel->self, mux_listener_channel->sock);
+}
+
+/* Callback on open confirmation in mux master for a mux client session. */
+static void
+mux_session_confirm(int id, int success, void *arg)
+{
+ struct mux_session_confirm_ctx *cctx = arg;
+ const char *display;
+ Channel *c, *cc;
+ int i;
+ Buffer reply;
+
+ if (cctx == NULL)
+ fatal("%s: cctx == NULL", __func__);
+ if ((c = channel_by_id(id)) == NULL)
+ fatal("%s: no channel for id %d", __func__, id);
+ if ((cc = channel_by_id(c->ctl_chan)) == NULL)
+ fatal("%s: channel %d lacks control channel %d", __func__,
+ id, c->ctl_chan);
+
+ if (!success) {
+ debug3("%s: sending failure reply", __func__);
+ /* prepare reply */
+ buffer_init(&reply);
+ buffer_put_int(&reply, MUX_S_FAILURE);
+ buffer_put_int(&reply, cctx->rid);
+ buffer_put_cstring(&reply, "Session open refused by peer");
+ goto done;
+ }
+
+ display = getenv("DISPLAY");
+ if (cctx->want_x_fwd && options.forward_x11 && display != NULL) {
+ char *proto, *data;
+
+ /* Get reasonable local authentication information. */
+ client_x11_get_proto(display, options.xauth_location,
+ options.forward_x11_trusted, options.forward_x11_timeout,
+ &proto, &data);
+ /* Request forwarding with authentication spoofing. */
+ debug("Requesting X11 forwarding with authentication "
+ "spoofing.");
+ x11_request_forwarding_with_spoofing(id, display, proto,
+ data, 1);
+ client_expect_confirm(id, "X11 forwarding", CONFIRM_WARN);
+ /* XXX exit_on_forward_failure */
+ }
+
+ if (cctx->want_agent_fwd && options.forward_agent) {
+ debug("Requesting authentication agent forwarding.");
+ channel_request_start(id, "auth-agent-req@openssh.com", 0);
+ packet_send();
+ }
+
+ client_session2_setup(id, cctx->want_tty, cctx->want_subsys,
+ cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env);
+
+ debug3("%s: sending success reply", __func__);
+ /* prepare reply */
+ buffer_init(&reply);
+ buffer_put_int(&reply, MUX_S_SESSION_OPENED);
+ buffer_put_int(&reply, cctx->rid);
+ buffer_put_int(&reply, c->self);
+
+ done:
+ /* Send reply */
+ buffer_put_string(&cc->output, buffer_ptr(&reply), buffer_len(&reply));
+ buffer_free(&reply);
+
+ if (cc->mux_pause <= 0)
+ fatal("%s: mux_pause %d", __func__, cc->mux_pause);
+ cc->mux_pause = 0; /* start processing messages again */
+ c->open_confirm_ctx = NULL;
+ buffer_free(&cctx->cmd);
+ xfree(cctx->term);
+ if (cctx->env != NULL) {
+ for (i = 0; cctx->env[i] != NULL; i++)
+ xfree(cctx->env[i]);
+ xfree(cctx->env);
+ }
+ xfree(cctx);
+}
+
+/* ** Multiplexing client support */
+
+/* Exit signal handler */
+static void
+control_client_sighandler(int signo)
+{
+ muxclient_terminate = signo;
+}
+
+/*
+ * Relay signal handler - used to pass some signals from mux client to
+ * mux master.
+ */
+static void
+control_client_sigrelay(int signo)
+{
+ int save_errno = errno;
+
+ if (muxserver_pid > 1)
+ kill(muxserver_pid, signo);
+
+ errno = save_errno;
+}
+
+static int
+mux_client_read(int fd, Buffer *b, u_int need)
+{
+ u_int have;
+ ssize_t len;
+ u_char *p;
+ struct pollfd pfd;
+
+ pfd.fd = fd;
+ pfd.events = POLLIN;
+ p = buffer_append_space(b, need);
+ for (have = 0; have < need; ) {
+ if (muxclient_terminate) {
+ errno = EINTR;
+ return -1;
+ }
+ len = read(fd, p + have, need - have);
+ if (len < 0) {
+ switch (errno) {
+#if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN)
+ case EWOULDBLOCK:
+#endif
+ case EAGAIN:
+ (void)poll(&pfd, 1, -1);
+ /* FALLTHROUGH */
+ case EINTR:
+ continue;
+ default:
+ return -1;
+ }
+ }
+ if (len == 0) {
+ errno = EPIPE;
+ return -1;
+ }
+ have += (u_int)len;
+ }
+ return 0;
+}
+
+static int
+mux_client_write_packet(int fd, Buffer *m)
+{
+ Buffer queue;
+ u_int have, need;
+ int oerrno, len;
+ u_char *ptr;
+ struct pollfd pfd;
+
+ pfd.fd = fd;
+ pfd.events = POLLOUT;
+ buffer_init(&queue);
+ buffer_put_string(&queue, buffer_ptr(m), buffer_len(m));
+
+ need = buffer_len(&queue);
+ ptr = buffer_ptr(&queue);
+
+ for (have = 0; have < need; ) {
+ if (muxclient_terminate) {
+ buffer_free(&queue);
+ errno = EINTR;
+ return -1;
+ }
+ len = write(fd, ptr + have, need - have);
+ if (len < 0) {
+ switch (errno) {
+#if defined(EWOULDBLOCK) && (EWOULDBLOCK != EAGAIN)
+ case EWOULDBLOCK:
+#endif
+ case EAGAIN:
+ (void)poll(&pfd, 1, -1);
+ /* FALLTHROUGH */
+ case EINTR:
+ continue;
+ default:
+ oerrno = errno;
+ buffer_free(&queue);
+ errno = oerrno;
+ return -1;
+ }
+ }
+ if (len == 0) {
+ buffer_free(&queue);
+ errno = EPIPE;
+ return -1;
+ }
+ have += (u_int)len;
+ }
+ buffer_free(&queue);
+ return 0;
+}
+
+static int
+mux_client_read_packet(int fd, Buffer *m)
+{
+ Buffer queue;
+ u_int need, have;
+ void *ptr;
+ int oerrno;
+
+ buffer_init(&queue);
+ if (mux_client_read(fd, &queue, 4) != 0) {
+ if ((oerrno = errno) == EPIPE)
+ debug3("%s: read header failed: %s", __func__, strerror(errno));
+ errno = oerrno;
+ return -1;
+ }
+ need = get_u32(buffer_ptr(&queue));
+ if (mux_client_read(fd, &queue, need) != 0) {
+ oerrno = errno;
+ debug3("%s: read body failed: %s", __func__, strerror(errno));
+ errno = oerrno;
+ return -1;
+ }
+ ptr = buffer_get_string_ptr(&queue, &have);
+ buffer_append(m, ptr, have);
+ buffer_free(&queue);
+ return 0;
+}
+
+static int
+mux_client_hello_exchange(int fd)
+{
+ Buffer m;
+ u_int type, ver;
+
+ buffer_init(&m);
+ buffer_put_int(&m, MUX_MSG_HELLO);
+ buffer_put_int(&m, SSHMUX_VER);
+ /* no extensions */
+
+ if (mux_client_write_packet(fd, &m) != 0)
+ fatal("%s: write packet: %s", __func__, strerror(errno));
+
+ buffer_clear(&m);
+
+ /* Read their HELLO */
+ if (mux_client_read_packet(fd, &m) != 0) {
+ buffer_free(&m);
+ return -1;
+ }
+
+ type = buffer_get_int(&m);
+ if (type != MUX_MSG_HELLO)
+ fatal("%s: expected HELLO (%u) received %u",
+ __func__, MUX_MSG_HELLO, type);
+ ver = buffer_get_int(&m);
+ if (ver != SSHMUX_VER)
+ fatal("Unsupported multiplexing protocol version %d "
+ "(expected %d)", ver, SSHMUX_VER);
+ debug2("%s: master version %u", __func__, ver);
+ /* No extensions are presently defined */
+ while (buffer_len(&m) > 0) {
+ char *name = buffer_get_string(&m, NULL);
+ char *value = buffer_get_string(&m, NULL);
+
+ debug2("Unrecognised master extension \"%s\"", name);
+ xfree(name);
+ xfree(value);
+ }
+ buffer_free(&m);
+ return 0;
+}
+
+static u_int
+mux_client_request_alive(int fd)
+{
+ Buffer m;
+ char *e;
+ u_int pid, type, rid;
+
+ debug3("%s: entering", __func__);
+
+ buffer_init(&m);
+ buffer_put_int(&m, MUX_C_ALIVE_CHECK);
+ buffer_put_int(&m, muxclient_request_id);
+
+ if (mux_client_write_packet(fd, &m) != 0)
+ fatal("%s: write packet: %s", __func__, strerror(errno));
+
+ buffer_clear(&m);
+
+ /* Read their reply */
+ if (mux_client_read_packet(fd, &m) != 0) {
+ buffer_free(&m);
+ return 0;
+ }
+
+ type = buffer_get_int(&m);
+ if (type != MUX_S_ALIVE) {
+ e = buffer_get_string(&m, NULL);
+ fatal("%s: master returned error: %s", __func__, e);
+ }
+
+ if ((rid = buffer_get_int(&m)) != muxclient_request_id)
+ fatal("%s: out of sequence reply: my id %u theirs %u",
+ __func__, muxclient_request_id, rid);
+ pid = buffer_get_int(&m);
+ buffer_free(&m);
+
+ debug3("%s: done pid = %u", __func__, pid);
+
+ muxclient_request_id++;
+
+ return pid;
+}
+
+static void
+mux_client_request_terminate(int fd)
+{
+ Buffer m;
+ char *e;
+ u_int type, rid;
+
+ debug3("%s: entering", __func__);
+
+ buffer_init(&m);
+ buffer_put_int(&m, MUX_C_TERMINATE);
+ buffer_put_int(&m, muxclient_request_id);
+
+ if (mux_client_write_packet(fd, &m) != 0)
+ fatal("%s: write packet: %s", __func__, strerror(errno));
+
+ buffer_clear(&m);
+
+ /* Read their reply */
+ if (mux_client_read_packet(fd, &m) != 0) {
+ /* Remote end exited already */
+ if (errno == EPIPE) {
+ buffer_free(&m);
+ return;
+ }
+ fatal("%s: read from master failed: %s",
+ __func__, strerror(errno));
+ }
+
+ type = buffer_get_int(&m);
+ if ((rid = buffer_get_int(&m)) != muxclient_request_id)
+ fatal("%s: out of sequence reply: my id %u theirs %u",
+ __func__, muxclient_request_id, rid);
+ switch (type) {
+ case MUX_S_OK:
+ break;
+ case MUX_S_PERMISSION_DENIED:
+ e = buffer_get_string(&m, NULL);
+ fatal("Master refused termination request: %s", e);
+ case MUX_S_FAILURE:
+ e = buffer_get_string(&m, NULL);
+ fatal("%s: termination request failed: %s", __func__, e);
+ default:
+ fatal("%s: unexpected response from master 0x%08x",
+ __func__, type);
+ }
+ buffer_free(&m);
+ muxclient_request_id++;
+}
+
+static int
+mux_client_request_forward(int fd, u_int ftype, Forward *fwd)
+{
+ Buffer m;
+ char *e, *fwd_desc;
+ u_int type, rid;
+
+ fwd_desc = format_forward(ftype, fwd);
+ debug("Requesting %s", fwd_desc);
+ xfree(fwd_desc);
+
+ buffer_init(&m);
+ buffer_put_int(&m, MUX_C_OPEN_FWD);
+ buffer_put_int(&m, muxclient_request_id);
+ buffer_put_int(&m, ftype);
+ buffer_put_cstring(&m,
+ fwd->listen_host == NULL ? "" : fwd->listen_host);
+ buffer_put_int(&m, fwd->listen_port);
+ buffer_put_cstring(&m,
+ fwd->connect_host == NULL ? "" : fwd->connect_host);
+ buffer_put_int(&m, fwd->connect_port);
+
+ if (mux_client_write_packet(fd, &m) != 0)
+ fatal("%s: write packet: %s", __func__, strerror(errno));
+
+ buffer_clear(&m);
+
+ /* Read their reply */
+ if (mux_client_read_packet(fd, &m) != 0) {
+ buffer_free(&m);
+ return -1;
+ }
+
+ type = buffer_get_int(&m);
+ if ((rid = buffer_get_int(&m)) != muxclient_request_id)
+ fatal("%s: out of sequence reply: my id %u theirs %u",
+ __func__, muxclient_request_id, rid);
+ switch (type) {
+ case MUX_S_OK:
+ break;
+ case MUX_S_REMOTE_PORT:
+ fwd->allocated_port = buffer_get_int(&m);
+ logit("Allocated port %u for remote forward to %s:%d",
+ fwd->allocated_port,
+ fwd->connect_host ? fwd->connect_host : "",
+ fwd->connect_port);
+ if (muxclient_command == SSHMUX_COMMAND_FORWARD)
+ fprintf(stdout, "%u\n", fwd->allocated_port);
+ break;
+ case MUX_S_PERMISSION_DENIED:
+ e = buffer_get_string(&m, NULL);
+ buffer_free(&m);
+ error("Master refused forwarding request: %s", e);
+ return -1;
+ case MUX_S_FAILURE:
+ e = buffer_get_string(&m, NULL);
+ buffer_free(&m);
+ error("%s: forwarding request failed: %s", __func__, e);
+ return -1;
+ default:
+ fatal("%s: unexpected response from master 0x%08x",
+ __func__, type);
+ }
+ buffer_free(&m);
+
+ muxclient_request_id++;
+ return 0;
+}
+
+static int
+mux_client_request_forwards(int fd)
+{
+ int i;
+
+ debug3("%s: requesting forwardings: %d local, %d remote", __func__,
+ options.num_local_forwards, options.num_remote_forwards);
+
+ /* XXX ExitOnForwardingFailure */
+ for (i = 0; i < options.num_local_forwards; i++) {
+ if (mux_client_request_forward(fd,
+ options.local_forwards[i].connect_port == 0 ?
+ MUX_FWD_DYNAMIC : MUX_FWD_LOCAL,
+ options.local_forwards + i) != 0)
+ return -1;
+ }
+ for (i = 0; i < options.num_remote_forwards; i++) {
+ if (mux_client_request_forward(fd, MUX_FWD_REMOTE,
+ options.remote_forwards + i) != 0)
+ return -1;
+ }
+ return 0;
+}
+
+static int
+mux_client_request_session(int fd)
+{
+ Buffer m;
+ char *e, *term;
+ u_int i, rid, sid, esid, exitval, type, exitval_seen;
+ extern char **environ;
+ int devnull, rawmode;
+
+ debug3("%s: entering", __func__);
+
+ if ((muxserver_pid = mux_client_request_alive(fd)) == 0) {
+ error("%s: master alive request failed", __func__);
+ return -1;
+ }
+
+ signal(SIGPIPE, SIG_IGN);
+
+ if (stdin_null_flag) {
+ if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1)
+ fatal("open(/dev/null): %s", strerror(errno));
+ if (dup2(devnull, STDIN_FILENO) == -1)
+ fatal("dup2: %s", strerror(errno));
+ if (devnull > STDERR_FILENO)
+ close(devnull);
+ }
+
+ term = getenv("TERM");
+
+ buffer_init(&m);
+ buffer_put_int(&m, MUX_C_NEW_SESSION);
+ buffer_put_int(&m, muxclient_request_id);
+ buffer_put_cstring(&m, ""); /* reserved */
+ buffer_put_int(&m, tty_flag);
+ buffer_put_int(&m, options.forward_x11);
+ buffer_put_int(&m, options.forward_agent);
+ buffer_put_int(&m, subsystem_flag);
+ buffer_put_int(&m, options.escape_char == SSH_ESCAPECHAR_NONE ?
+ 0xffffffff : (u_int)options.escape_char);
+ buffer_put_cstring(&m, term == NULL ? "" : term);
+ buffer_put_string(&m, buffer_ptr(&command), buffer_len(&command));
+
+ if (options.num_send_env > 0 && environ != NULL) {
+ /* Pass environment */
+ for (i = 0; environ[i] != NULL; i++) {
+ if (env_permitted(environ[i])) {
+ buffer_put_cstring(&m, environ[i]);
+ }
+ }
+ }
+
+ if (mux_client_write_packet(fd, &m) != 0)
+ fatal("%s: write packet: %s", __func__, strerror(errno));
+
+ /* Send the stdio file descriptors */
+ if (mm_send_fd(fd, STDIN_FILENO) == -1 ||
+ mm_send_fd(fd, STDOUT_FILENO) == -1 ||
+ mm_send_fd(fd, STDERR_FILENO) == -1)
+ fatal("%s: send fds failed", __func__);
+
+ debug3("%s: session request sent", __func__);
+
+ /* Read their reply */
+ buffer_clear(&m);
+ if (mux_client_read_packet(fd, &m) != 0) {
+ error("%s: read from master failed: %s",
+ __func__, strerror(errno));
+ buffer_free(&m);
+ return -1;
+ }
+
+ type = buffer_get_int(&m);
+ if ((rid = buffer_get_int(&m)) != muxclient_request_id)
+ fatal("%s: out of sequence reply: my id %u theirs %u",
+ __func__, muxclient_request_id, rid);
+ switch (type) {
+ case MUX_S_SESSION_OPENED:
+ sid = buffer_get_int(&m);
+ debug("%s: master session id: %u", __func__, sid);
+ break;
+ case MUX_S_PERMISSION_DENIED:
+ e = buffer_get_string(&m, NULL);
+ buffer_free(&m);
+ error("Master refused session request: %s", e);
+ return -1;
+ case MUX_S_FAILURE:
+ e = buffer_get_string(&m, NULL);
+ buffer_free(&m);
+ error("%s: session request failed: %s", __func__, e);
+ return -1;
+ default:
+ buffer_free(&m);
+ error("%s: unexpected response from master 0x%08x",
+ __func__, type);
+ return -1;
+ }
+ muxclient_request_id++;
+
+ signal(SIGHUP, control_client_sighandler);
+ signal(SIGINT, control_client_sighandler);
+ signal(SIGTERM, control_client_sighandler);
+ signal(SIGWINCH, control_client_sigrelay);
+
+ rawmode = tty_flag;
+ if (tty_flag)
+ enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
+
+ /*
+ * Stick around until the controlee closes the client_fd.
+ * Before it does, it is expected to write an exit message.
+ * This process must read the value and wait for the closure of
+ * the client_fd; if this one closes early, the multiplex master will
+ * terminate early too (possibly losing data).
+ */
+ for (exitval = 255, exitval_seen = 0;;) {
+ buffer_clear(&m);
+ if (mux_client_read_packet(fd, &m) != 0)
+ break;
+ type = buffer_get_int(&m);
+ switch (type) {
+ case MUX_S_TTY_ALLOC_FAIL:
+ if ((esid = buffer_get_int(&m)) != sid)
+ fatal("%s: tty alloc fail on unknown session: "
+ "my id %u theirs %u",
+ __func__, sid, esid);
+ leave_raw_mode(options.request_tty ==
+ REQUEST_TTY_FORCE);
+ rawmode = 0;
+ continue;
+ case MUX_S_EXIT_MESSAGE:
+ if ((esid = buffer_get_int(&m)) != sid)
+ fatal("%s: exit on unknown session: "
+ "my id %u theirs %u",
+ __func__, sid, esid);
+ if (exitval_seen)
+ fatal("%s: exitval sent twice", __func__);
+ exitval = buffer_get_int(&m);
+ exitval_seen = 1;
+ continue;
+ default:
+ e = buffer_get_string(&m, NULL);
+ fatal("%s: master returned error: %s", __func__, e);
+ }
+ }
+
+ close(fd);
+ if (rawmode)
+ leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
+
+ if (muxclient_terminate) {
+ debug2("Exiting on signal %d", muxclient_terminate);
+ exitval = 255;
+ } else if (!exitval_seen) {
+ debug2("Control master terminated unexpectedly");
+ exitval = 255;
+ } else
+ debug2("Received exit status from master %d", exitval);
+
+ if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET)
+ fprintf(stderr, "Shared connection to %s closed.\r\n", host);
+
+ exit(exitval);
+}
+
+static int
+mux_client_request_stdio_fwd(int fd)
+{
+ Buffer m;
+ char *e;
+ u_int type, rid, sid;
+ int devnull;
+
+ debug3("%s: entering", __func__);
+
+ if ((muxserver_pid = mux_client_request_alive(fd)) == 0) {
+ error("%s: master alive request failed", __func__);
+ return -1;
+ }
+
+ signal(SIGPIPE, SIG_IGN);
+
+ if (stdin_null_flag) {
+ if ((devnull = open(_PATH_DEVNULL, O_RDONLY)) == -1)
+ fatal("open(/dev/null): %s", strerror(errno));
+ if (dup2(devnull, STDIN_FILENO) == -1)
+ fatal("dup2: %s", strerror(errno));
+ if (devnull > STDERR_FILENO)
+ close(devnull);
+ }
+
+ buffer_init(&m);
+ buffer_put_int(&m, MUX_C_NEW_STDIO_FWD);
+ buffer_put_int(&m, muxclient_request_id);
+ buffer_put_cstring(&m, ""); /* reserved */
+ buffer_put_cstring(&m, stdio_forward_host);
+ buffer_put_int(&m, stdio_forward_port);
+
+ if (mux_client_write_packet(fd, &m) != 0)
+ fatal("%s: write packet: %s", __func__, strerror(errno));
+
+ /* Send the stdio file descriptors */
+ if (mm_send_fd(fd, STDIN_FILENO) == -1 ||
+ mm_send_fd(fd, STDOUT_FILENO) == -1)
+ fatal("%s: send fds failed", __func__);
+
+ debug3("%s: stdio forward request sent", __func__);
+
+ /* Read their reply */
+ buffer_clear(&m);
+
+ if (mux_client_read_packet(fd, &m) != 0) {
+ error("%s: read from master failed: %s",
+ __func__, strerror(errno));
+ buffer_free(&m);
+ return -1;
+ }
+
+ type = buffer_get_int(&m);
+ if ((rid = buffer_get_int(&m)) != muxclient_request_id)
+ fatal("%s: out of sequence reply: my id %u theirs %u",
+ __func__, muxclient_request_id, rid);
+ switch (type) {
+ case MUX_S_SESSION_OPENED:
+ sid = buffer_get_int(&m);
+ debug("%s: master session id: %u", __func__, sid);
+ break;
+ case MUX_S_PERMISSION_DENIED:
+ e = buffer_get_string(&m, NULL);
+ buffer_free(&m);
+ fatal("Master refused stdio forwarding request: %s", e);
+ case MUX_S_FAILURE:
+ e = buffer_get_string(&m, NULL);
+ buffer_free(&m);
+ fatal("%s: stdio forwarding request failed: %s", __func__, e);
+ default:
+ buffer_free(&m);
+ error("%s: unexpected response from master 0x%08x",
+ __func__, type);
+ return -1;
+ }
+ muxclient_request_id++;
+
+ signal(SIGHUP, control_client_sighandler);
+ signal(SIGINT, control_client_sighandler);
+ signal(SIGTERM, control_client_sighandler);
+ signal(SIGWINCH, control_client_sigrelay);
+
+ /*
+ * Stick around until the controlee closes the client_fd.
+ */
+ buffer_clear(&m);
+ if (mux_client_read_packet(fd, &m) != 0) {
+ if (errno == EPIPE ||
+ (errno == EINTR && muxclient_terminate != 0))
+ return 0;
+ fatal("%s: mux_client_read_packet: %s",
+ __func__, strerror(errno));
+ }
+ fatal("%s: master returned unexpected message %u", __func__, type);
+}
+
+static void
+mux_client_request_stop_listening(int fd)
+{
+ Buffer m;
+ char *e;
+ u_int type, rid;
+
+ debug3("%s: entering", __func__);
+
+ buffer_init(&m);
+ buffer_put_int(&m, MUX_C_STOP_LISTENING);
+ buffer_put_int(&m, muxclient_request_id);
+
+ if (mux_client_write_packet(fd, &m) != 0)
+ fatal("%s: write packet: %s", __func__, strerror(errno));
+
+ buffer_clear(&m);
+
+ /* Read their reply */
+ if (mux_client_read_packet(fd, &m) != 0)
+ fatal("%s: read from master failed: %s",
+ __func__, strerror(errno));
+
+ type = buffer_get_int(&m);
+ if ((rid = buffer_get_int(&m)) != muxclient_request_id)
+ fatal("%s: out of sequence reply: my id %u theirs %u",
+ __func__, muxclient_request_id, rid);
+ switch (type) {
+ case MUX_S_OK:
+ break;
+ case MUX_S_PERMISSION_DENIED:
+ e = buffer_get_string(&m, NULL);
+ fatal("Master refused stop listening request: %s", e);
+ case MUX_S_FAILURE:
+ e = buffer_get_string(&m, NULL);
+ fatal("%s: stop listening request failed: %s", __func__, e);
+ default:
+ fatal("%s: unexpected response from master 0x%08x",
+ __func__, type);
+ }
+ buffer_free(&m);
+ muxclient_request_id++;
+}
+
+/* Multiplex client main loop. */
+void
+muxclient(const char *path)
+{
+ struct sockaddr_un addr;
+ socklen_t sun_len;
+ int sock;
+ u_int pid;
+
+ if (muxclient_command == 0) {
+ if (stdio_forward_host != NULL)
+ muxclient_command = SSHMUX_COMMAND_STDIO_FWD;
+ else
+ muxclient_command = SSHMUX_COMMAND_OPEN;
+ }
+
+ switch (options.control_master) {
+ case SSHCTL_MASTER_AUTO:
+ case SSHCTL_MASTER_AUTO_ASK:
+ debug("auto-mux: Trying existing master");
+ /* FALLTHROUGH */
+ case SSHCTL_MASTER_NO:
+ break;
+ default:
+ return;
+ }
+
+ memset(&addr, '\0', sizeof(addr));
+ addr.sun_family = AF_UNIX;
+ sun_len = offsetof(struct sockaddr_un, sun_path) +
+ strlen(path) + 1;
+
+ if (strlcpy(addr.sun_path, path,
+ sizeof(addr.sun_path)) >= sizeof(addr.sun_path))
+ fatal("ControlPath too long");
+
+ if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
+ fatal("%s socket(): %s", __func__, strerror(errno));
+
+ if (connect(sock, (struct sockaddr *)&addr, sun_len) == -1) {
+ switch (muxclient_command) {
+ case SSHMUX_COMMAND_OPEN:
+ case SSHMUX_COMMAND_STDIO_FWD:
+ break;
+ default:
+ fatal("Control socket connect(%.100s): %s", path,
+ strerror(errno));
+ }
+ if (errno == ECONNREFUSED &&
+ options.control_master != SSHCTL_MASTER_NO) {
+ debug("Stale control socket %.100s, unlinking", path);
+ unlink(path);
+ } else if (errno == ENOENT) {
+ debug("Control socket \"%.100s\" does not exist", path);
+ } else {
+ error("Control socket connect(%.100s): %s", path,
+ strerror(errno));
+ }
+ close(sock);
+ return;
+ }
+ set_nonblock(sock);
+
+ if (mux_client_hello_exchange(sock) != 0) {
+ error("%s: master hello exchange failed", __func__);
+ close(sock);
+ return;
+ }
+
+ switch (muxclient_command) {
+ case SSHMUX_COMMAND_ALIVE_CHECK:
+ if ((pid = mux_client_request_alive(sock)) == 0)
+ fatal("%s: master alive check failed", __func__);
+ fprintf(stderr, "Master running (pid=%d)\r\n", pid);
+ exit(0);
+ case SSHMUX_COMMAND_TERMINATE:
+ mux_client_request_terminate(sock);
+ fprintf(stderr, "Exit request sent.\r\n");
+ exit(0);
+ case SSHMUX_COMMAND_FORWARD:
+ if (mux_client_request_forwards(sock) != 0)
+ fatal("%s: master forward request failed", __func__);
+ exit(0);
+ case SSHMUX_COMMAND_OPEN:
+ if (mux_client_request_forwards(sock) != 0) {
+ error("%s: master forward request failed", __func__);
+ return;
+ }
+ mux_client_request_session(sock);
+ return;
+ case SSHMUX_COMMAND_STDIO_FWD:
+ mux_client_request_stdio_fwd(sock);
+ exit(0);
+ case SSHMUX_COMMAND_STOP:
+ mux_client_request_stop_listening(sock);
+ fprintf(stderr, "Stop listening request sent.\r\n");
+ exit(0);
+ default:
+ fatal("unrecognised muxclient_command %d", muxclient_command);
+ }
+}