diff options
| -rw-r--r-- | ChangeLog | 8 | ||||
| -rw-r--r-- | Makefile.in | 4 | ||||
| -rw-r--r-- | clientloop.c | 308 | ||||
| -rw-r--r-- | clientloop.h | 20 | ||||
| -rw-r--r-- | mux.c | 646 | ||||
| -rw-r--r-- | ssh.c | 309 |
6 files changed, 699 insertions, 596 deletions
@@ -111,6 +111,12 @@ was to try the first address and give up. Reported by stig AT venaas.com in bz#343 great feedback and ok markus@ + - djm@cvs.openbsd.org 2008/05/09 14:18:44 + [clientloop.c clientloop.h ssh.c mux.c] + tidy up session multiplexing code, moving it into its own file and + making the function names more consistent - making ssh.c and + clientloop.c a fair bit more readable. + ok markus@ 20080403 - (djm) [openbsd-compat/bsd-poll.c] Include stdlib.h to avoid compile- @@ -3971,4 +3977,4 @@ OpenServer 6 and add osr5bigcrypt support so when someone migrates passwords between UnixWare and OpenServer they will still work. OK dtucker@ -$Id: ChangeLog,v 1.4925 2008/05/19 05:37:09 djm Exp $ +$Id: ChangeLog,v 1.4926 2008/05/19 06:00:08 djm Exp $ diff --git a/Makefile.in b/Makefile.in index 6b488fec..b57b9b72 100644 --- a/Makefile.in +++ b/Makefile.in @@ -1,4 +1,4 @@ -# $Id: Makefile.in,v 1.289 2008/03/13 01:41:31 djm Exp $ +# $Id: Makefile.in,v 1.290 2008/05/19 06:00:08 djm Exp $ # uncomment if you run a non bourne compatable shell. Ie. csh #SHELL = @SH@ @@ -74,7 +74,7 @@ LIBSSH_OBJS=acss.o authfd.o authfile.o bufaux.o bufbn.o buffer.o \ entropy.o scard-opensc.o gss-genr.o umac.o SSHOBJS= ssh.o readconf.o clientloop.o sshtty.o \ - sshconnect.o sshconnect1.o sshconnect2.o + sshconnect.o sshconnect1.o sshconnect2.o mux.o SSHDOBJS=sshd.o auth-rhosts.o auth-passwd.o auth-rsa.o auth-rh-rsa.o \ sshpty.o sshlogin.o servconf.o serverloop.o \ diff --git a/clientloop.c b/clientloop.c index 7bd1af60..c87aa5a0 100644 --- a/clientloop.c +++ b/clientloop.c @@ -1,4 +1,4 @@ -/* $OpenBSD: clientloop.c,v 1.191 2008/05/09 04:55:56 djm Exp $ */ +/* $OpenBSD: clientloop.c,v 1.192 2008/05/09 14:18:44 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -121,7 +121,7 @@ extern int stdin_null_flag; extern int no_shell_flag; /* Control socket */ -extern int control_fd; +extern int muxserver_sock; /* * Name of the host we are connecting to. This is the name given on the @@ -162,17 +162,6 @@ static int session_closed = 0; /* In SSH2: login session closed. */ static void client_init_dispatch(void); int session_ident = -1; -struct confirm_ctx { - int want_tty; - int want_subsys; - int want_x_fwd; - int want_agent_fwd; - Buffer cmd; - char *term; - struct termios tio; - char **env; -}; - struct channel_reply_ctx { const char *request_type; int id, do_close; @@ -538,8 +527,8 @@ client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, if (packet_have_data_to_write()) FD_SET(connection_out, *writesetp); - if (control_fd != -1) - FD_SET(control_fd, *readsetp); + if (muxserver_sock != -1) + FD_SET(muxserver_sock, *readsetp); /* * Wait for something to happen. This will suspend the process until @@ -707,284 +696,6 @@ client_expect_confirm(int id, const char *request, int do_close) } static void -client_extra_session2_setup(int id, void *arg) -{ - struct confirm_ctx *cctx = arg; - const char *display; - Channel *c; - int i; - - if (cctx == NULL) - fatal("%s: cctx == NULL", __func__); - if ((c = channel_lookup(id)) == NULL) - fatal("%s: no channel for id %d", __func__, id); - - 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); - - 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); -} - -static void -client_process_control(fd_set *readset) -{ - Buffer m; - Channel *c; - int client_fd, new_fd[3], ver, allowed, window, packetmax; - socklen_t addrlen; - struct sockaddr_storage addr; - struct confirm_ctx *cctx; - char *cmd; - u_int i, j, len, env_len, command, flags; - uid_t euid; - gid_t egid; - - /* - * Accept connection on control socket - */ - if (control_fd == -1 || !FD_ISSET(control_fd, readset)) - return; - - memset(&addr, 0, sizeof(addr)); - addrlen = sizeof(addr); - if ((client_fd = accept(control_fd, - (struct sockaddr*)&addr, &addrlen)) == -1) { - error("%s accept: %s", __func__, strerror(errno)); - return; - } - - if (getpeereid(client_fd, &euid, &egid) < 0) { - error("%s getpeereid failed: %s", __func__, strerror(errno)); - close(client_fd); - return; - } - if ((euid != 0) && (getuid() != euid)) { - error("control mode uid mismatch: peer euid %u != uid %u", - (u_int) euid, (u_int) getuid()); - close(client_fd); - return; - } - - unset_nonblock(client_fd); - - /* Read command */ - buffer_init(&m); - if (ssh_msg_recv(client_fd, &m) == -1) { - error("%s: client msg_recv failed", __func__); - close(client_fd); - buffer_free(&m); - return; - } - if ((ver = buffer_get_char(&m)) != SSHMUX_VER) { - error("%s: wrong client version %d", __func__, ver); - buffer_free(&m); - close(client_fd); - return; - } - - allowed = 1; - command = buffer_get_int(&m); - flags = buffer_get_int(&m); - - buffer_clear(&m); - - switch (command) { - case SSHMUX_COMMAND_OPEN: - if (options.control_master == SSHCTL_MASTER_ASK || - options.control_master == SSHCTL_MASTER_AUTO_ASK) - allowed = ask_permission("Allow shared connection " - "to %s? ", host); - /* continue below */ - break; - case SSHMUX_COMMAND_TERMINATE: - if (options.control_master == SSHCTL_MASTER_ASK || - options.control_master == SSHCTL_MASTER_AUTO_ASK) - allowed = ask_permission("Terminate shared connection " - "to %s? ", host); - if (allowed) - quit_pending = 1; - /* FALLTHROUGH */ - case SSHMUX_COMMAND_ALIVE_CHECK: - /* Reply for SSHMUX_COMMAND_TERMINATE and ALIVE_CHECK */ - buffer_clear(&m); - buffer_put_int(&m, allowed); - buffer_put_int(&m, getpid()); - if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) { - error("%s: client msg_send failed", __func__); - close(client_fd); - buffer_free(&m); - return; - } - buffer_free(&m); - close(client_fd); - return; - default: - error("Unsupported command %d", command); - buffer_free(&m); - close(client_fd); - return; - } - - /* Reply for SSHMUX_COMMAND_OPEN */ - buffer_clear(&m); - buffer_put_int(&m, allowed); - buffer_put_int(&m, getpid()); - if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) { - error("%s: client msg_send failed", __func__); - close(client_fd); - buffer_free(&m); - return; - } - - if (!allowed) { - error("Refused control connection"); - close(client_fd); - buffer_free(&m); - return; - } - - buffer_clear(&m); - if (ssh_msg_recv(client_fd, &m) == -1) { - error("%s: client msg_recv failed", __func__); - close(client_fd); - buffer_free(&m); - return; - } - if ((ver = buffer_get_char(&m)) != SSHMUX_VER) { - error("%s: wrong client version %d", __func__, ver); - buffer_free(&m); - close(client_fd); - return; - } - - cctx = xcalloc(1, sizeof(*cctx)); - cctx->want_tty = (flags & SSHMUX_FLAG_TTY) != 0; - cctx->want_subsys = (flags & SSHMUX_FLAG_SUBSYS) != 0; - cctx->want_x_fwd = (flags & SSHMUX_FLAG_X11_FWD) != 0; - cctx->want_agent_fwd = (flags & SSHMUX_FLAG_AGENT_FWD) != 0; - cctx->term = buffer_get_string(&m, &len); - - cmd = buffer_get_string(&m, &len); - buffer_init(&cctx->cmd); - buffer_append(&cctx->cmd, cmd, strlen(cmd)); - - env_len = buffer_get_int(&m); - env_len = MIN(env_len, 4096); - debug3("%s: receiving %d env vars", __func__, env_len); - if (env_len != 0) { - cctx->env = xcalloc(env_len + 1, sizeof(*cctx->env)); - for (i = 0; i < env_len; i++) - cctx->env[i] = buffer_get_string(&m, &len); - cctx->env[i] = NULL; - } - - debug2("%s: accepted tty %d, subsys %d, cmd %s", __func__, - cctx->want_tty, cctx->want_subsys, cmd); - xfree(cmd); - - /* Gather fds from client */ - for(i = 0; i < 3; i++) { - if ((new_fd[i] = mm_receive_fd(client_fd)) == -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); - close(client_fd); - xfree(cctx); - return; - } - } - - debug2("%s: got fds stdin %d, stdout %d, stderr %d", __func__, - new_fd[0], new_fd[1], new_fd[2]); - - /* 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)); - - /* This roundtrip is just for synchronisation of ttymodes */ - buffer_clear(&m); - if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) { - error("%s: client msg_send failed", __func__); - close(client_fd); - close(new_fd[0]); - close(new_fd[1]); - close(new_fd[2]); - buffer_free(&m); - xfree(cctx->term); - if (env_len != 0) { - for (i = 0; i < env_len; i++) - xfree(cctx->env[i]); - xfree(cctx->env); - } - return; - } - buffer_free(&m); - - /* 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]); - - set_nonblock(client_fd); - - window = CHAN_SES_WINDOW_DEFAULT; - packetmax = CHAN_SES_PACKET_DEFAULT; - if (cctx->want_tty) { - window >>= 1; - packetmax >>= 1; - } - - c = channel_new("session", SSH_CHANNEL_OPENING, - new_fd[0], new_fd[1], new_fd[2], window, packetmax, - CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0); - - /* XXX */ - c->ctl_fd = client_fd; - - debug3("%s: channel_new: %d", __func__, c->self); - - channel_send_open(c->self); - channel_register_open_confirm(c->self, - client_extra_session2_setup, cctx); -} - -static void process_cmdline(void) { void (*handler)(int); @@ -1448,8 +1159,8 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) connection_in = packet_get_connection_in(); connection_out = packet_get_connection_out(); max_fd = MAX(connection_in, connection_out); - if (control_fd != -1) - max_fd = MAX(max_fd, control_fd); + if (muxserver_sock != -1) + max_fd = MAX(max_fd, muxserver_sock); if (!compat20) { /* enable nonblocking unless tty */ @@ -1569,7 +1280,10 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) client_process_net_input(readset); /* Accept control connections. */ - client_process_control(readset); + if (muxserver_sock != -1 &&FD_ISSET(muxserver_sock, readset)) { + if (muxserver_accept_control()) + quit_pending = 1; + } if (quit_pending) break; @@ -2157,7 +1871,7 @@ cleanup_exit(int i) { leave_raw_mode(); leave_non_blocking(); - if (options.control_path != NULL && control_fd != -1) + if (options.control_path != NULL && muxserver_sock != -1) unlink(options.control_path); _exit(i); } diff --git a/clientloop.h b/clientloop.h index cb2d7c08..6f8e7012 100644 --- a/clientloop.h +++ b/clientloop.h @@ -1,4 +1,4 @@ -/* $OpenBSD: clientloop.h,v 1.18 2008/05/08 13:06:11 djm Exp $ */ +/* $OpenBSD: clientloop.h,v 1.19 2008/05/09 14:18:44 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> @@ -58,3 +58,21 @@ int client_request_tun_fwd(int, int, int); #define SSHMUX_FLAG_SUBSYS (1<<1) /* Subsystem request on open */ #define SSHMUX_FLAG_X11_FWD (1<<2) /* Request X11 forwarding */ #define SSHMUX_FLAG_AGENT_FWD (1<<3) /* Request agent forwarding */ + +/* Multiplexing routines */ + +struct mux_session_confirm_ctx { + int want_tty; + int want_subsys; + int want_x_fwd; + int want_agent_fwd; + Buffer cmd; + char *term; + struct termios tio; + char **env; +}; + +/* mux.c */ +void muxserver_listen(void); +int muxserver_accept_control(void); +void muxclient(const char *); @@ -0,0 +1,646 @@ +/* $OpenBSD: mux.c,v 1.1 2008/05/09 14:18:44 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 */ + +#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> +#include <util.h> +#include <paths.h> + +#include "openbsd-compat/sys-queue.h" +#include "xmalloc.h" +#include "log.h" +#include "ssh.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; +int subsystem_flag; +extern Buffer command; + +/* fd to control socket */ +int muxserver_sock = -1; + +/* 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; + + +/* ** Multiplexing master support */ + +/* Prepare a mux master to listen on a Unix domain socket. */ +void +muxserver_listen(void) +{ + struct sockaddr_un addr; + mode_t old_umask; + int addr_len; + + 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; + addr_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, addr_len) == -1) { + muxserver_sock = -1; + if (errno == EINVAL || errno == EADDRINUSE) + fatal("ControlSocket %s already exists", + options.control_path); + 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); +} + +/* Callback on open confirmation in mux master for a mux client session. */ +static void +client_extra_session2_setup(int id, void *arg) +{ + struct mux_session_confirm_ctx *cctx = arg; + const char *display; + Channel *c; + int i; + + if (cctx == NULL) + fatal("%s: cctx == NULL", __func__); + if ((c = channel_lookup(id)) == NULL) + fatal("%s: no channel for id %d", __func__, id); + + 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); + + 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); +} + +/* + * Accept a connection on the mux master socket and process the + * client's request. Returns flag indicating whether mux master should + * begin graceful close. + */ +int +muxserver_accept_control(void) +{ + Buffer m; + Channel *c; + int client_fd, new_fd[3], ver, allowed, window, packetmax; + socklen_t addrlen; + struct sockaddr_storage addr; + struct mux_session_confirm_ctx *cctx; + char *cmd; + u_int i, j, len, env_len, mux_command, flags; + uid_t euid; + gid_t egid; + int start_close = 0; + + /* + * Accept connection on control socket + */ + memset(&addr, 0, sizeof(addr)); + addrlen = sizeof(addr); + if ((client_fd = accept(muxserver_sock, + (struct sockaddr*)&addr, &addrlen)) == -1) { + error("%s accept: %s", __func__, strerror(errno)); + return 0; + } + + if (getpeereid(client_fd, &euid, &egid) < 0) { + error("%s getpeereid failed: %s", __func__, strerror(errno)); + close(client_fd); + return 0; + } + if ((euid != 0) && (getuid() != euid)) { + error("control mode uid mismatch: peer euid %u != uid %u", + (u_int) euid, (u_int) getuid()); + close(client_fd); + return 0; + } + + /* XXX handle asynchronously */ + unset_nonblock(client_fd); + + /* Read command */ + buffer_init(&m); + if (ssh_msg_recv(client_fd, &m) == -1) { + error("%s: client msg_recv failed", __func__); + close(client_fd); + buffer_free(&m); + return 0; + } + if ((ver = buffer_get_char(&m)) != SSHMUX_VER) { + error("%s: wrong client version %d", __func__, ver); + buffer_free(&m); + close(client_fd); + return 0; + } + + allowed = 1; + mux_command = buffer_get_int(&m); + flags = buffer_get_int(&m); + + buffer_clear(&m); + + switch (mux_command) { + case SSHMUX_COMMAND_OPEN: + if (options.control_master == SSHCTL_MASTER_ASK || + options.control_master == SSHCTL_MASTER_AUTO_ASK) + allowed = ask_permission("Allow shared connection " + "to %s? ", host); + /* continue below */ + break; + case SSHMUX_COMMAND_TERMINATE: + if (options.control_master == SSHCTL_MASTER_ASK || + options.control_master == SSHCTL_MASTER_AUTO_ASK) + allowed = ask_permission("Terminate shared connection " + "to %s? ", host); + if (allowed) + start_close = 1; + /* FALLTHROUGH */ + case SSHMUX_COMMAND_ALIVE_CHECK: + /* Reply for SSHMUX_COMMAND_TERMINATE and ALIVE_CHECK */ + buffer_clear(&m); + buffer_put_int(&m, allowed); + buffer_put_int(&m, getpid()); + if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) { + error("%s: client msg_send failed", __func__); + close(client_fd); + buffer_free(&m); + return start_close; + } + buffer_free(&m); + close(client_fd); + return start_close; + default: + error("Unsupported command %d", mux_command); + buffer_free(&m); + close(client_fd); + return 0; + } + + /* Reply for SSHMUX_COMMAND_OPEN */ + buffer_clear(&m); + buffer_put_int(&m, allowed); + buffer_put_int(&m, getpid()); + if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) { + error("%s: client msg_send failed", __func__); + close(client_fd); + buffer_free(&m); + return 0; + } + + if (!allowed) { + error("Refused control connection"); + close(client_fd); + buffer_free(&m); + return 0; + } + + buffer_clear(&m); + if (ssh_msg_recv(client_fd, &m) == -1) { + error("%s: client msg_recv failed", __func__); + close(client_fd); + buffer_free(&m); + return 0; + } + if ((ver = buffer_get_char(&m)) != SSHMUX_VER) { + error("%s: wrong client version %d", __func__, ver); + buffer_free(&m); + close(client_fd); + return 0; + } + + cctx = xcalloc(1, sizeof(*cctx)); + cctx->want_tty = (flags & SSHMUX_FLAG_TTY) != 0; + cctx->want_subsys = (flags & SSHMUX_FLAG_SUBSYS) != 0; + cctx->want_x_fwd = (flags & SSHMUX_FLAG_X11_FWD) != 0; + cctx->want_agent_fwd = (flags & SSHMUX_FLAG_AGENT_FWD) != 0; + cctx->term = buffer_get_string(&m, &len); + + cmd = buffer_get_string(&m, &len); + buffer_init(&cctx->cmd); + buffer_append(&cctx->cmd, cmd, strlen(cmd)); + + env_len = buffer_get_int(&m); + env_len = MIN(env_len, 4096); + debug3("%s: receiving %d env vars", __func__, env_len); + if (env_len != 0) { + cctx->env = xcalloc(env_len + 1, sizeof(*cctx->env)); + for (i = 0; i < env_len; i++) + cctx->env[i] = buffer_get_string(&m, &len); + cctx->env[i] = NULL; + } + + debug2("%s: accepted tty %d, subsys %d, cmd %s", __func__, + cctx->want_tty, cctx->want_subsys, cmd); + xfree(cmd); + + /* Gather fds from client */ + for(i = 0; i < 3; i++) { + if ((new_fd[i] = mm_receive_fd(client_fd)) == -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); + close(client_fd); + xfree(cctx); + return 0; + } + } + + debug2("%s: got fds stdin %d, stdout %d, stderr %d", __func__, + new_fd[0], new_fd[1], new_fd[2]); + + /* 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)); + + /* This roundtrip is just for synchronisation of ttymodes */ + buffer_clear(&m); + if (ssh_msg_send(client_fd, SSHMUX_VER, &m) == -1) { + error("%s: client msg_send failed", __func__); + close(client_fd); + close(new_fd[0]); + close(new_fd[1]); + close(new_fd[2]); + buffer_free(&m); + xfree(cctx->term); + if (env_len != 0) { + for (i = 0; i < env_len; i++) + xfree(cctx->env[i]); + xfree(cctx->env); + } + return 0; + } + buffer_free(&m); + + /* 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]); + + set_nonblock(client_fd); + + window = CHAN_SES_WINDOW_DEFAULT; + packetmax = CHAN_SES_PACKET_DEFAULT; + if (cctx->want_tty) { + window >>= 1; + packetmax >>= 1; + } + + c = channel_new("session", SSH_CHANNEL_OPENING, + new_fd[0], new_fd[1], new_fd[2], window, packetmax, + CHAN_EXTENDED_WRITE, "client-session", /*nonblock*/0); + + /* XXX */ + c->ctl_fd = client_fd; + + debug3("%s: channel_new: %d", __func__, c->self); + + channel_send_open(c->self); + channel_register_open_confirm(c->self, + client_extra_session2_setup, cctx); + return 0; +} + +/* ** 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; +} + +/* 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)) + fatal("env_permitted: name '%.100s...' too long", env); + + for (i = 0; i < options.num_send_env; i++) + if (match_pattern(name, options.send_env[i])) + return (1); + + return (0); +} + +/* Multiplex client main loop. */ +void +muxclient(const char *path) +{ + struct sockaddr_un addr; + int i, r, fd, sock, exitval[2], num_env, addr_len; + Buffer m; + char *term; + extern char **environ; + u_int flags; + + if (muxclient_command == 0) + 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; + addr_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, addr_len) == -1) { + if (muxclient_command != SSHMUX_COMMAND_OPEN) { + 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; + } + + if (stdin_null_flag) { + if ((fd = open(_PATH_DEVNULL, O_RDONLY)) == -1) + fatal("open(/dev/null): %s", strerror(errno)); + if (dup2(fd, STDIN_FILENO) == -1) + fatal("dup2: %s", strerror(errno)); + if (fd > STDERR_FILENO) + close(fd); + } + + term = getenv("TERM"); + + flags = 0; + if (tty_flag) + flags |= SSHMUX_FLAG_TTY; + if (subsystem_flag) + flags |= SSHMUX_FLAG_SUBSYS; + if (options.forward_x11) + flags |= SSHMUX_FLAG_X11_FWD; + if (options.forward_agent) + flags |= SSHMUX_FLAG_AGENT_FWD; + + signal(SIGPIPE, SIG_IGN); + + buffer_init(&m); + + /* Send our command to server */ + buffer_put_int(&m, muxclient_command); + buffer_put_int(&m, flags); + if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1) + fatal("%s: msg_send", __func__); + buffer_clear(&m); + + /* Get authorisation status and PID of controlee */ + if (ssh_msg_recv(sock, &m) == -1) + fatal("%s: msg_recv", __func__); + if (buffer_get_char(&m) != SSHMUX_VER) + fatal("%s: wrong version", __func__); + if (buffer_get_int(&m) != 1) + fatal("Connection to master denied"); + muxserver_pid = buffer_get_int(&m); + + buffer_clear(&m); + + switch (muxclient_command) { + case SSHMUX_COMMAND_ALIVE_CHECK: + fprintf(stderr, "Master running (pid=%d)\r\n", + muxserver_pid); + exit(0); + case SSHMUX_COMMAND_TERMINATE: + fprintf(stderr, "Exit request sent.\r\n"); + exit(0); + case SSHMUX_COMMAND_OPEN: + /* continue below */ + break; + default: + fatal("silly muxclient_command %d", muxclient_command); + } + + /* SSHMUX_COMMAND_OPEN */ + buffer_put_cstring(&m, term ? term : ""); + buffer_append(&command, "\0", 1); + buffer_put_cstring(&m, buffer_ptr(&command)); + + if (options.num_send_env == 0 || environ == NULL) { + buffer_put_int(&m, 0); + } else { + /* Pass environment */ + num_env = 0; + for (i = 0; environ[i] != NULL; i++) + if (env_permitted(environ[i])) + num_env++; /* Count */ + + buffer_put_int(&m, num_env); + + for (i = 0; environ[i] != NULL && num_env >= 0; i++) + if (env_permitted(environ[i])) { + num_env--; + buffer_put_cstring(&m, environ[i]); + } + } + + if (ssh_msg_send(sock, SSHMUX_VER, &m) == -1) + fatal("%s: msg_send", __func__); + + if (mm_send_fd(sock, STDIN_FILENO) == -1 || + mm_send_fd(sock, STDOUT_FILENO) == -1 || + mm_send_fd(sock, STDERR_FILENO) == -1) + fatal("%s: send fds failed", __func__); + + /* Wait for reply, so master has a chance to gather ttymodes */ + buffer_clear(&m); + if (ssh_msg_recv(sock, &m) == -1) + fatal("%s: msg_recv", __func__); + if (buffer_get_char(&m) != SSHMUX_VER) + fatal("%s: wrong version", __func__); + buffer_free(&m); + + 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(); + + /* + * Stick around until the controlee closes the client_fd. + * Before it does, it is expected to write this process' exit + * value (one int). 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). + */ + exitval[0] = 0; + for (i = 0; !muxclient_terminate && i < (int)sizeof(exitval);) { + r = read(sock, (char *)exitval + i, sizeof(exitval) - i); + if (r == 0) { + debug2("Received EOF from master"); + break; + } + if (r == -1) { + if (errno == EINTR) + continue; + fatal("%s: read %s", __func__, strerror(errno)); + } + i += r; + } + + close(sock); + leave_raw_mode(); + if (i > (int)sizeof(int)) + fatal("%s: master returned too much data (%d > %lu)", + __func__, i, sizeof(int)); + if (muxclient_terminate) { + debug2("Exiting on signal %d", muxclient_terminate); + exitval[0] = 255; + } else if (i < (int)sizeof(int)) { + debug2("Control master terminated unexpectedly"); + exitval[0] = 255; + } else + debug2("Received exit status from master %d", exitval[0]); + + if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET) + fprintf(stderr, "Shared connection to %s closed.\r\n", host); + + exit(exitval[0]); +} |