| /* $OpenBSD: mux.c,v 1.18 2010/05/16 12:55:51 markus 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 int force_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_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 |
| |
| /* 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 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 }, |
| { 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 (options.num_local_forwards + 1 >= |
| SSH_MAX_FORWARDS_PER_DIRECTION || |
| 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 (options.num_remote_forwards + 1 >= |
| SSH_MAX_FORWARDS_PER_DIRECTION || |
| 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 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; |
| } |
| |
| /* 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); |
| } |
| |
| /* 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; |
| |
| if (options.control_path == NULL || |
| options.control_master == SSHCTL_MASTER_NO) |
| return; |
| |
| debug("setting up multiplex master socket"); |
| |
| 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)) |
| fatal("ControlPath too long"); |
| |
| 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) { |
| muxserver_sock = -1; |
| if (errno == EINVAL || errno == EADDRINUSE) { |
| error("ControlSocket %s already exists, " |
| "disabling multiplexing", options.control_path); |
| 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)); |
| |
| 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, addr.sun_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, &proto, &data); |
| /* Request forwarding with authentication spoofing. */ |
| debug("Requesting X11 forwarding with authentication spoofing."); |
| x11_request_forwarding_with_spoofing(id, display, proto, data); |
| /* XXX wait for reply */ |
| } |
| |
| 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: session 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; |
| |
| 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 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: |
| 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); |
| |
| if (tty_flag) |
| enter_raw_mode(force_tty_flag); |
| |
| /* |
| * 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); |
| if (type != MUX_S_EXIT_MESSAGE) { |
| e = buffer_get_string(&m, NULL); |
| fatal("%s: master returned error: %s", __func__, e); |
| } |
| if ((esid = buffer_get_int(&m)) != sid) |
| fatal("%s: exit on unknown session: my id %u theirs %u", |
| __func__, sid, esid); |
| debug("%s: master session id: %u", __func__, sid); |
| if (exitval_seen) |
| fatal("%s: exitval sent twice", __func__); |
| exitval = buffer_get_int(&m); |
| exitval_seen = 1; |
| } |
| |
| close(fd); |
| leave_raw_mode(force_tty_flag); |
| |
| 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 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); |
| } |
| |
| /* 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 == 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); |
| default: |
| fatal("unrecognised muxclient_command %d", muxclient_command); |
| } |
| } |