X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/182ccbba349bd384ee6eb18a606142dd7551fbec..3867aa0affaccd191ff433656ce3ef9f8da3ad3b:/ssh.c diff --git a/ssh.c b/ssh.c index d4954ec3..99b25afc 100644 --- a/ssh.c +++ b/ssh.c @@ -40,7 +40,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: ssh.c,v 1.208 2004/03/10 09:45:06 markus Exp $"); +RCSID("$OpenBSD: ssh.c,v 1.232 2005/03/01 10:09:52 djm Exp $"); #include #include @@ -53,31 +53,31 @@ RCSID("$OpenBSD: ssh.c,v 1.208 2004/03/10 09:45:06 markus Exp $"); #include "xmalloc.h" #include "packet.h" #include "buffer.h" +#include "bufaux.h" #include "channels.h" #include "key.h" #include "authfd.h" #include "authfile.h" #include "pathnames.h" +#include "dispatch.h" #include "clientloop.h" #include "log.h" #include "readconf.h" #include "sshconnect.h" -#include "tildexpand.h" -#include "dispatch.h" #include "misc.h" #include "kex.h" #include "mac.h" -#include "sshtty.h" +#include "sshpty.h" +#include "match.h" +#include "msg.h" +#include "monitor_fdpass.h" +#include "uidswap.h" #ifdef SMARTCARD #include "scard.h" #endif -#ifdef HAVE___PROGNAME extern char *__progname; -#else -char *__progname; -#endif /* Flag indicating whether debug mode is on. This can be set on the command line. */ int debug_flag = 0; @@ -141,16 +141,28 @@ static int client_global_request_id = 0; /* pid of proxycommand child process */ pid_t proxy_command_pid = 0; +/* fd to control socket */ +int control_fd = -1; + +/* Multiplexing control command */ +static u_int mux_command = SSHMUX_COMMAND_OPEN; + +/* Only used in control client mode */ +volatile sig_atomic_t control_client_terminate = 0; +u_int control_server_pid = 0; + /* Prints a help message to the user. This function never returns. */ static void usage(void) { fprintf(stderr, -"usage: ssh [-1246AaCfghkNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]\n" -" [-D port] [-e escape_char] [-F configfile] [-i identity_file]\n" -" [-L port:host:hostport] [-l login_name] [-m mac_spec] [-o option]\n" -" [-p port] [-R port:host:hostport] [user@]hostname [command]\n" +"usage: ssh [-1246AaCfgkMNnqsTtVvXxY] [-b bind_address] [-c cipher_spec]\n" +" [-D [listen-host:]port] [-e escape_char] [-F configfile]\n" +" [-i identity_file] [-L [listen-host:]port:host:hostport]\n" +" [-l login_name] [-m mac_spec] [-O ctl_cmd] [-o option] [-p port]\n" +" [-R [listen-host:]port:host:hostport] [-S ctl_path]\n" +" [user@]hostname [command]\n" ); exit(1); } @@ -158,6 +170,7 @@ usage(void) static int ssh_session(void); static int ssh_session2(void); static void load_public_identity_files(void); +static void control_client(const char *path); /* * Main program for the ssh client. @@ -166,14 +179,13 @@ int main(int ac, char **av) { int i, opt, exit_status; - u_short fwd_port, fwd_host_port; - char sfwd_port[6], sfwd_host_port[6]; char *p, *cp, *line, buf[256]; struct stat st; struct passwd *pw; int dummy; extern int optind, optreset; extern char *optarg; + Forward fwd; __progname = ssh_get_progname(av[0]); init_rng(); @@ -228,7 +240,7 @@ main(int ac, char **av) again: while ((opt = getopt(ac, av, - "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:NPR:TVXY")) != -1) { + "1246ab:c:e:fgi:kl:m:no:p:qstvxACD:F:I:L:MNO:PR:S:TVXY")) != -1) { switch (opt) { case '1': options.protocol = SSH_PROTO_1; @@ -262,6 +274,14 @@ again: case 'g': options.gateway_ports = 1; break; + case 'O': + if (strcmp(optarg, "check") == 0) + mux_command = SSHMUX_COMMAND_ALIVE_CHECK; + else if (strcmp(optarg, "exit") == 0) + mux_command = SSHMUX_COMMAND_TERMINATE; + else + fatal("Invalid multiplex command."); + break; case 'P': /* deprecated */ options.use_privileged_port = 0; break; @@ -277,7 +297,8 @@ again: case 'i': if (stat(optarg, &st) < 0) { fprintf(stderr, "Warning: Identity file %s " - "does not exist.\n", optarg); + "not accessible: %s.\n", optarg, + strerror(errno)); break; } if (options.num_identity_files >= @@ -308,14 +329,10 @@ again: options.log_level++; break; } - /* fallthrough */ + /* FALLTHROUGH */ case 'V': - fprintf(stderr, - "%s, SSH protocols %d.%d/%d.%d, %s\n", - SSH_VERSION, - PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1, - PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, - SSLeay_version(SSLEAY_VERSION)); + fprintf(stderr, "%s, %s\n", + SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); if (opt == 'V') exit(0); break; @@ -341,7 +358,7 @@ again: if (ciphers_valid(optarg)) { /* SSH2 only */ options.ciphers = xstrdup(optarg); - options.cipher = SSH_CIPHER_ILLEGAL; + options.cipher = SSH_CIPHER_INVALID; } else { /* SSH1 only */ options.cipher = cipher_number(optarg); @@ -368,6 +385,10 @@ again: exit(1); } break; + case 'M': + options.control_master = + (options.control_master >= 1) ? 2 : 1; + break; case 'p': options.port = a2port(optarg); if (options.port == 0) { @@ -380,39 +401,51 @@ again: break; case 'L': - case 'R': - if (sscanf(optarg, "%5[0123456789]:%255[^:]:%5[0123456789]", - sfwd_port, buf, sfwd_host_port) != 3 && - sscanf(optarg, "%5[0123456789]/%255[^/]/%5[0123456789]", - sfwd_port, buf, sfwd_host_port) != 3) { + if (parse_forward(&fwd, optarg)) + add_local_forward(&options, &fwd); + else { fprintf(stderr, - "Bad forwarding specification '%s'\n", + "Bad local forwarding specification '%s'\n", optarg); - usage(); - /* NOTREACHED */ + exit(1); } - if ((fwd_port = a2port(sfwd_port)) == 0 || - (fwd_host_port = a2port(sfwd_host_port)) == 0) { + break; + + case 'R': + if (parse_forward(&fwd, optarg)) { + add_remote_forward(&options, &fwd); + } else { fprintf(stderr, - "Bad forwarding port(s) '%s'\n", optarg); + "Bad remote forwarding specification " + "'%s'\n", optarg); exit(1); } - if (opt == 'L') - add_local_forward(&options, fwd_port, buf, - fwd_host_port); - else if (opt == 'R') - add_remote_forward(&options, fwd_port, buf, - fwd_host_port); break; case 'D': - fwd_port = a2port(optarg); - if (fwd_port == 0) { + cp = p = xstrdup(optarg); + memset(&fwd, '\0', sizeof(fwd)); + fwd.connect_host = "socks"; + if ((fwd.listen_host = hpdelim(&cp)) == NULL) { + fprintf(stderr, "Bad dynamic forwarding " + "specification '%.100s'\n", optarg); + exit(1); + } + if (cp != NULL) { + fwd.listen_port = a2port(cp); + fwd.listen_host = cleanhostname(fwd.listen_host); + } else { + fwd.listen_port = a2port(fwd.listen_host); + fwd.listen_host = ""; + } + + if (fwd.listen_port == 0) { fprintf(stderr, "Bad dynamic port '%s'\n", optarg); exit(1); } - add_local_forward(&options, fwd_port, "socks", 0); + add_local_forward(&options, &fwd); + xfree(p); break; case 'C': @@ -436,6 +469,11 @@ again: case 's': subsystem_flag = 1; break; + case 'S': + if (options.control_path != NULL) + free(options.control_path); + options.control_path = xstrdup(optarg); + break; case 'b': options.bind_address = optarg; break; @@ -530,16 +568,17 @@ again: * file if the user specifies a config file on the command line. */ if (config != NULL) { - if (!read_config_file(config, host, &options)) + if (!read_config_file(config, host, &options, 0)) fatal("Can't open user config file %.100s: " "%.100s", config, strerror(errno)); } else { snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, _PATH_SSH_USER_CONFFILE); - (void)read_config_file(buf, host, &options); + (void)read_config_file(buf, host, &options, 1); /* Read systemwide configuration file after use config. */ - (void)read_config_file(_PATH_HOST_CONFIG_FILE, host, &options); + (void)read_config_file(_PATH_HOST_CONFIG_FILE, host, + &options, 0); } /* Fill configuration defaults. */ @@ -569,6 +608,13 @@ again: strcmp(options.proxy_command, "none") == 0) options.proxy_command = NULL; + if (options.control_path != NULL) { + options.control_path = tilde_expand_filename( + options.control_path, original_real_uid); + } + if (options.control_path != NULL && options.control_master == 0) + control_client(options.control_path); /* This doesn't return */ + /* Open a connection to the remote host. */ if (ssh_connect(host, &hostaddr, options.port, options.address_family, options.connection_attempts, @@ -624,8 +670,10 @@ again: * user's home directory if it happens to be on a NFS volume where * root is mapped to nobody. */ - seteuid(original_real_uid); - setuid(original_real_uid); + if (original_effective_uid == 0) { + PRIV_START; + permanently_set_uid(pw); + } /* * Now that we are back to our own permissions, create ~/.ssh @@ -681,6 +729,9 @@ again: exit_status = compat20 ? ssh_session2() : ssh_session(); packet_close(); + if (options.control_path != NULL && control_fd != -1) + unlink(options.control_path); + /* * Send SIGHUP to proxy command if used. We don't wait() in * case it hangs and instead rely on init to reap the child @@ -780,17 +831,17 @@ x11_get_proto(char **_proto, char **_data) * for the local connection. */ if (!got_data) { - u_int32_t rand = 0; + u_int32_t rnd = 0; logit("Warning: No xauth data; " "using fake authentication data for X11 forwarding."); strlcpy(proto, SSH_X11_PROTO, sizeof proto); for (i = 0; i < 16; i++) { if (i % 4 == 0) - rand = arc4random(); + rnd = arc4random(); snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", - rand & 0xff); - rand >>= 8; + rnd & 0xff); + rnd >>= 8; } } } @@ -803,14 +854,19 @@ ssh_init_forwarding(void) /* Initiate local TCP/IP port forwardings. */ for (i = 0; i < options.num_local_forwards; i++) { - debug("Connections to local port %d forwarded to remote address %.200s:%d", - options.local_forwards[i].port, - options.local_forwards[i].host, - options.local_forwards[i].host_port); + debug("Local connections to %.200s:%d forwarded to remote " + "address %.200s:%d", + (options.local_forwards[i].listen_host == NULL) ? + (options.gateway_ports ? "*" : "LOCALHOST") : + options.local_forwards[i].listen_host, + options.local_forwards[i].listen_port, + options.local_forwards[i].connect_host, + options.local_forwards[i].connect_port); success += channel_setup_local_fwd_listener( - options.local_forwards[i].port, - options.local_forwards[i].host, - options.local_forwards[i].host_port, + options.local_forwards[i].listen_host, + options.local_forwards[i].listen_port, + options.local_forwards[i].connect_host, + options.local_forwards[i].connect_port, options.gateway_ports); } if (i > 0 && success == 0) @@ -818,14 +874,17 @@ ssh_init_forwarding(void) /* Initiate remote TCP/IP port forwardings. */ for (i = 0; i < options.num_remote_forwards; i++) { - debug("Connections to remote port %d forwarded to local address %.200s:%d", - options.remote_forwards[i].port, - options.remote_forwards[i].host, - options.remote_forwards[i].host_port); + debug("Remote connections from %.200s:%d forwarded to " + "local address %.200s:%d", + options.remote_forwards[i].listen_host, + options.remote_forwards[i].listen_port, + options.remote_forwards[i].connect_host, + options.remote_forwards[i].connect_port); channel_request_remote_forwarding( - options.remote_forwards[i].port, - options.remote_forwards[i].host, - options.remote_forwards[i].host_port); + options.remote_forwards[i].listen_host, + options.remote_forwards[i].listen_port, + options.remote_forwards[i].connect_host, + options.remote_forwards[i].connect_port); } } @@ -977,7 +1036,7 @@ ssh_session(void) } static void -client_subsystem_reply(int type, u_int32_t seq, void *ctxt) +ssh_subsystem_reply(int type, u_int32_t seq, void *ctxt) { int id, len; @@ -1001,48 +1060,61 @@ client_global_request_reply_fwd(int type, u_int32_t seq, void *ctxt) return; debug("remote forward %s for: listen %d, connect %s:%d", type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure", - options.remote_forwards[i].port, - options.remote_forwards[i].host, - options.remote_forwards[i].host_port); + options.remote_forwards[i].listen_port, + options.remote_forwards[i].connect_host, + options.remote_forwards[i].connect_port); if (type == SSH2_MSG_REQUEST_FAILURE) - logit("Warning: remote port forwarding failed for listen port %d", - options.remote_forwards[i].port); + logit("Warning: remote port forwarding failed for listen " + "port %d", options.remote_forwards[i].listen_port); } -/* request pty/x11/agent/tcpfwd/shell for channel */ static void -ssh_session2_setup(int id, void *arg) +ssh_control_listener(void) { - int len; - int interactive = 0; - struct termios tio; + struct sockaddr_un addr; + mode_t old_umask; + int addr_len; - debug2("ssh_session2_setup: id %d", id); + if (options.control_path == NULL || options.control_master <= 0) + return; - if (tty_flag) { - struct winsize ws; - char *cp; - cp = getenv("TERM"); - if (!cp) - cp = ""; - /* Store window size in the packet. */ - if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) - memset(&ws, 0, sizeof(ws)); + memset(&addr, '\0', sizeof(addr)); + addr.sun_family = AF_UNIX; + addr_len = offsetof(struct sockaddr_un, sun_path) + + strlen(options.control_path) + 1; - channel_request_start(id, "pty-req", 0); - packet_put_cstring(cp); - packet_put_int(ws.ws_col); - packet_put_int(ws.ws_row); - packet_put_int(ws.ws_xpixel); - packet_put_int(ws.ws_ypixel); - tio = get_saved_tio(); - tty_make_modes(/*ignored*/ 0, &tio); - packet_send(); - interactive = 1; - /* XXX wait for reply */ + if (strlcpy(addr.sun_path, options.control_path, + sizeof(addr.sun_path)) >= sizeof(addr.sun_path)) + fatal("ControlPath too long"); + + if ((control_fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) + fatal("%s socket(): %s\n", __func__, strerror(errno)); + + old_umask = umask(0177); + if (bind(control_fd, (struct sockaddr*)&addr, addr_len) == -1) { + control_fd = -1; + if (errno == EINVAL) + fatal("ControlSocket %s already exists", + options.control_path); + else + fatal("%s bind(): %s\n", __func__, strerror(errno)); } - if (options.forward_x11 && - getenv("DISPLAY") != NULL) { + umask(old_umask); + + if (listen(control_fd, 64) == -1) + fatal("%s listen(): %s\n", __func__, strerror(errno)); + + set_nonblock(control_fd); +} + +/* request pty/x11/agent/tcpfwd/shell for channel */ +static void +ssh_session2_setup(int id, void *arg) +{ + extern char **environ; + + int interactive = tty_flag; + if (options.forward_x11 && getenv("DISPLAY") != NULL) { char *proto, *data; /* Get reasonable local authentication information. */ x11_get_proto(&proto, &data); @@ -1060,27 +1132,8 @@ ssh_session2_setup(int id, void *arg) packet_send(); } - len = buffer_len(&command); - if (len > 0) { - if (len > 900) - len = 900; - if (subsystem_flag) { - debug("Sending subsystem: %.*s", len, (u_char *)buffer_ptr(&command)); - channel_request_start(id, "subsystem", /*want reply*/ 1); - /* register callback for reply */ - /* XXX we assume that client_loop has already been called */ - dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &client_subsystem_reply); - dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &client_subsystem_reply); - } else { - debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command)); - channel_request_start(id, "exec", 0); - } - packet_put_string(buffer_ptr(&command), buffer_len(&command)); - packet_send(); - } else { - channel_request_start(id, "shell", 0); - packet_send(); - } + client_session2_setup(id, tty_flag, subsystem_flag, getenv("TERM"), + NULL, fileno(stdin), &command, environ, &ssh_subsystem_reply); packet_set_interactive(interactive); } @@ -1126,7 +1179,7 @@ ssh_session2_open(void) channel_send_open(c->self); if (!no_shell_flag) - channel_register_confirm(c->self, ssh_session2_setup); + channel_register_confirm(c->self, ssh_session2_setup, NULL); return c->self; } @@ -1138,6 +1191,7 @@ ssh_session2(void) /* XXX should be pre-session */ ssh_init_forwarding(); + ssh_control_listener(); if (!no_shell_flag || (datafellows & SSH_BUG_DUMMYCHAN)) id = ssh_session2_open(); @@ -1191,3 +1245,186 @@ load_public_identity_files(void) options.identity_keys[i] = public; } } + +static void +control_client_sighandler(int signo) +{ + control_client_terminate = signo; +} + +static void +control_client_sigrelay(int signo) +{ + if (control_server_pid > 1) + kill(control_server_pid, signo); +} + +static int +env_permitted(char *env) +{ + int i; + char name[1024], *cp; + + strlcpy(name, env, sizeof(name)); + if ((cp = strchr(name, '=')) == NULL) + return (0); + + *cp = '\0'; + + for (i = 0; i < options.num_send_env; i++) + if (match_pattern(name, options.send_env[i])) + return (1); + + return (0); +} + +static void +control_client(const char *path) +{ + struct sockaddr_un addr; + int i, r, fd, sock, exitval, num_env, addr_len; + Buffer m; + char *term; + extern char **environ; + u_int flags; + + 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); + } + + 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) + fatal("Couldn't connect to %s: %s", path, strerror(errno)); + + if ((term = getenv("TERM")) == NULL) + term = ""; + + flags = 0; + if (tty_flag) + flags |= SSHMUX_FLAG_TTY; + if (subsystem_flag) + flags |= SSHMUX_FLAG_SUBSYS; + + buffer_init(&m); + + /* Send our command to server */ + buffer_put_int(&m, mux_command); + buffer_put_int(&m, flags); + if (ssh_msg_send(sock, /* version */1, &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) != 1) + fatal("%s: wrong version", __func__); + if (buffer_get_int(&m) != 1) + fatal("Connection to master denied"); + control_server_pid = buffer_get_int(&m); + + buffer_clear(&m); + + switch (mux_command) { + case SSHMUX_COMMAND_ALIVE_CHECK: + fprintf(stderr, "Master running (pid=%d)\r\n", + control_server_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 mux_command %d", mux_command); + } + + /* SSHMUX_COMMAND_OPEN */ + buffer_put_cstring(&m, 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, /* version */1, &m) == -1) + fatal("%s: msg_send", __func__); + + mm_send_fd(sock, STDIN_FILENO); + mm_send_fd(sock, STDOUT_FILENO); + mm_send_fd(sock, STDERR_FILENO); + + /* 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) != 1) + 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 */ + exitval = 0; + for (;!control_client_terminate;) { + r = read(sock, &exitval, sizeof(exitval)); + if (r == 0) { + debug2("Received EOF from master"); + break; + } + if (r > 0) + debug2("Received exit status from master %d", exitval); + if (r == -1 && errno != EINTR) + fatal("%s: read %s", __func__, strerror(errno)); + } + + if (control_client_terminate) + debug2("Exiting on signal %d", control_client_terminate); + + close(sock); + + leave_raw_mode(); + + if (tty_flag && options.log_level != SYSLOG_LEVEL_QUIET) + fprintf(stderr, "Connection to master closed.\r\n"); + + exit(exitval); +}