=================================================================== RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/clientloop.c,v retrieving revision 1.112 retrieving revision 1.112.2.2 diff -u -r1.112 -r1.112.2.2 --- src/usr.bin/ssh/clientloop.c 2003/06/28 16:23:06 1.112 +++ src/usr.bin/ssh/clientloop.c 2004/08/19 22:37:31 1.112.2.2 @@ -59,7 +59,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: clientloop.c,v 1.112 2003/06/28 16:23:06 deraadt Exp $"); +RCSID("$OpenBSD: clientloop.c,v 1.112.2.2 2004/08/19 22:37:31 brad Exp $"); #include "ssh.h" #include "ssh1.h" @@ -79,9 +79,11 @@ #include "clientloop.h" #include "authfd.h" #include "atomicio.h" -#include "sshtty.h" +#include "sshpty.h" #include "misc.h" -#include "readpass.h" +#include "monitor_fdpass.h" +#include "match.h" +#include "msg.h" /* import options */ extern Options options; @@ -89,6 +91,12 @@ /* Flag indicating that stdin should be redirected from /dev/null. */ extern int stdin_null_flag; +/* Flag indicating that no shell has been requested */ +extern int no_shell_flag; + +/* Control socket */ +extern int control_fd; + /* * Name of the host we are connecting to. This is the name given on the * command line, or the HostName specified for the user-supplied name in a @@ -124,22 +132,33 @@ static int connection_out; /* Connection to server (output). */ static int need_rekeying; /* Set to non-zero if rekeying is requested. */ static int session_closed = 0; /* In SSH2: login session closed. */ +static int server_alive_timeouts = 0; static void client_init_dispatch(void); int session_ident = -1; +struct confirm_ctx { + int want_tty; + int want_subsys; + Buffer cmd; + char *term; + struct termios tio; + char **env; +}; + /*XXX*/ extern Kex *xxx_kex; +void ssh_process_session2_setup(int, int, int, Buffer *); + /* Restores stdin to blocking mode. */ static void leave_non_blocking(void) { if (in_non_blocking_mode) { - (void) fcntl(fileno(stdin), F_SETFL, 0); + unset_nonblock(fileno(stdin)); in_non_blocking_mode = 0; - fatal_remove_cleanup((void (*) (void *)) leave_non_blocking, NULL); } } @@ -149,8 +168,7 @@ enter_non_blocking(void) { in_non_blocking_mode = 1; - (void) fcntl(fileno(stdin), F_SETFL, O_NONBLOCK); - fatal_add_cleanup((void (*) (void *)) leave_non_blocking, NULL); + set_nonblock(fileno(stdin)); } /* @@ -290,19 +308,13 @@ /** XXX race */ received_window_change_signal = 0; - if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) - return; - debug2("client_check_window_change: changed"); if (compat20) { - channel_request_start(session_ident, "window-change", 0); - packet_put_int(ws.ws_col); - packet_put_int(ws.ws_row); - packet_put_int(ws.ws_xpixel); - packet_put_int(ws.ws_ypixel); - packet_send(); + channel_send_window_changes(); } else { + if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) + return; packet_start(SSH_CMSG_WINDOW_SIZE); packet_put_int(ws.ws_row); packet_put_int(ws.ws_col); @@ -312,15 +324,35 @@ } } +static void +client_global_request_reply(int type, u_int32_t seq, void *ctxt) +{ + server_alive_timeouts = 0; + client_global_request_reply_fwd(type, seq, ctxt); +} + +static void +server_alive_check(void) +{ + if (++server_alive_timeouts > options.server_alive_count_max) + packet_disconnect("Timeout, server not responding."); + packet_start(SSH2_MSG_GLOBAL_REQUEST); + packet_put_cstring("keepalive@openssh.com"); + packet_put_char(1); /* boolean: want reply */ + packet_send(); +} + /* * Waits until the client can do something (some data becomes available on * one of the file descriptors). */ - static void client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, - int *maxfdp, int *nallocp, int rekeying) + int *maxfdp, u_int *nallocp, int rekeying) { + struct timeval tv, *tvp; + int ret; + /* Add any selections by the channel mechanism. */ channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, rekeying); @@ -359,16 +391,24 @@ if (packet_have_data_to_write()) FD_SET(connection_out, *writesetp); + if (control_fd != -1) + FD_SET(control_fd, *readsetp); + /* * Wait for something to happen. This will suspend the process until * some selected descriptor can be read, written, or has some other - * event pending. Note: if you want to implement SSH_MSG_IGNORE - * messages to fool traffic analysis, this might be the place to do - * it: just have a random timeout for the select, and send a random - * SSH_MSG_IGNORE packet when the timeout expires. + * event pending. */ - if (select((*maxfdp)+1, *readsetp, *writesetp, NULL, NULL) < 0) { + if (options.server_alive_interval == 0 || !compat20) + tvp = NULL; + else { + tv.tv_sec = options.server_alive_interval; + tv.tv_usec = 0; + tvp = &tv; + } + ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); + if (ret < 0) { char buf[100]; /* @@ -385,7 +425,8 @@ snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); buffer_append(&stderr_buffer, buf, strlen(buf)); quit_pending = 1; - } + } else if (ret == 0) + server_alive_check(); } static void @@ -472,12 +513,229 @@ } static void +client_subsystem_reply(int type, u_int32_t seq, void *ctxt) +{ + int id; + Channel *c; + + id = packet_get_int(); + packet_check_eom(); + + if ((c = channel_lookup(id)) == NULL) { + error("%s: no channel for id %d", __func__, id); + return; + } + + if (type == SSH2_MSG_CHANNEL_SUCCESS) + debug2("Request suceeded on channel %d", id); + else if (type == SSH2_MSG_CHANNEL_FAILURE) { + error("Request failed on channel %d", id); + channel_free(c); + } +} + +static void +client_extra_session2_setup(int id, void *arg) +{ + struct confirm_ctx *cctx = arg; + 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); + + client_session2_setup(id, cctx->want_tty, cctx->want_subsys, + cctx->term, &cctx->tio, c->rfd, &cctx->cmd, cctx->env, + client_subsystem_reply); + + c->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, i, allowed; + socklen_t addrlen; + struct sockaddr_storage addr; + struct confirm_ctx *cctx; + char *cmd; + u_int len, env_len; + 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; + } + + allowed = 1; + if (options.control_master == 2) { + char *p, prompt[1024]; + + allowed = 0; + snprintf(prompt, sizeof(prompt), + "Allow shared connection to %s? ", host); + p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF); + if (p != NULL) { + /* + * Accept empty responses and responses consisting + * of the word "yes" as affirmative. + */ + if (*p == '\0' || *p == '\n' || + strcasecmp(p, "yes") == 0) + allowed = 1; + xfree(p); + } + } + + unset_nonblock(client_fd); + + buffer_init(&m); + + buffer_put_int(&m, allowed); + buffer_put_int(&m, getpid()); + if (ssh_msg_send(client_fd, /* version */0, &m) == -1) { + error("%s: client msg_send failed", __func__); + close(client_fd); + buffer_free(&m); + return; + } + buffer_clear(&m); + + if (!allowed) { + error("Refused control connection"); + close(client_fd); + buffer_free(&m); + return; + } + + 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)) != 0) { + error("%s: wrong client version %d", __func__, ver); + buffer_free(&m); + close(client_fd); + return; + } + + cctx = xmalloc(sizeof(*cctx)); + memset(cctx, 0, sizeof(*cctx)); + + cctx->want_tty = buffer_get_int(&m); + cctx->want_subsys = buffer_get_int(&m); + 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 = xmalloc(sizeof(*cctx->env) * (env_len + 1)); + 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); + + /* Gather fds from client */ + new_fd[0] = mm_receive_fd(client_fd); + new_fd[1] = mm_receive_fd(client_fd); + new_fd[2] = mm_receive_fd(client_fd); + + 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)); + + buffer_clear(&m); + if (ssh_msg_send(client_fd, /* version */0, &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); + 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); + + c = channel_new("session", SSH_CHANNEL_OPENING, + new_fd[0], new_fd[1], new_fd[2], + CHAN_SES_WINDOW_DEFAULT, CHAN_SES_PACKET_DEFAULT, + 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_confirm(c->self, client_extra_session2_setup, cctx); +} + +static void process_cmdline(void) { void (*handler)(int); char *s, *cmd; u_short fwd_port, fwd_host_port; char buf[1024], sfwd_port[6], sfwd_host_port[6]; + int delete = 0; int local = 0; leave_raw_mode(); @@ -487,44 +745,77 @@ goto out; while (*s && isspace(*s)) s++; - if (*s == 0) + if (*s == '-') + s++; /* Skip cmdline '-', if any */ + if (*s == '\0') goto out; - if (strlen(s) < 2 || s[0] != '-' || !(s[1] == 'L' || s[1] == 'R')) { + + if (*s == 'h' || *s == 'H' || *s == '?') { + logit("Commands:"); + logit(" -Lport:host:hostport Request local forward"); + logit(" -Rport:host:hostport Request remote forward"); + logit(" -KRhostport Cancel remote forward"); + goto out; + } + + if (*s == 'K') { + delete = 1; + s++; + } + if (*s != 'L' && *s != 'R') { logit("Invalid command."); goto out; } - if (s[1] == 'L') + if (*s == 'L') local = 1; - if (!local && !compat20) { + if (local && delete) { + logit("Not supported."); + goto out; + } + if ((!local || delete) && !compat20) { logit("Not supported for SSH protocol version 1."); goto out; } - s += 2; + + s++; while (*s && isspace(*s)) s++; - if (sscanf(s, "%5[0-9]:%255[^:]:%5[0-9]", - sfwd_port, buf, sfwd_host_port) != 3 && - sscanf(s, "%5[0-9]/%255[^/]/%5[0-9]", - sfwd_port, buf, sfwd_host_port) != 3) { - logit("Bad forwarding specification."); - goto out; - } - if ((fwd_port = a2port(sfwd_port)) == 0 || - (fwd_host_port = a2port(sfwd_host_port)) == 0) { - logit("Bad forwarding port(s)."); - goto out; - } - if (local) { - if (channel_setup_local_fwd_listener(fwd_port, buf, - fwd_host_port, options.gateway_ports) < 0) { - logit("Port forwarding failed."); + if (delete) { + if (sscanf(s, "%5[0-9]", sfwd_host_port) != 1) { + logit("Bad forwarding specification."); goto out; } - } else - channel_request_remote_forwarding(fwd_port, buf, - fwd_host_port); - logit("Forwarding port."); + if ((fwd_host_port = a2port(sfwd_host_port)) == 0) { + logit("Bad forwarding port(s)."); + goto out; + } + channel_request_rforward_cancel(fwd_host_port); + } else { + if (sscanf(s, "%5[0-9]:%255[^:]:%5[0-9]", + sfwd_port, buf, sfwd_host_port) != 3 && + sscanf(s, "%5[0-9]/%255[^/]/%5[0-9]", + sfwd_port, buf, sfwd_host_port) != 3) { + logit("Bad forwarding specification."); + goto out; + } + if ((fwd_port = a2port(sfwd_port)) == 0 || + (fwd_host_port = a2port(sfwd_host_port)) == 0) { + logit("Bad forwarding port(s)."); + goto out; + } + if (local) { + if (channel_setup_local_fwd_listener(fwd_port, buf, + fwd_host_port, options.gateway_ports) < 0) { + logit("Port forwarding failed."); + goto out; + } + } else + channel_request_remote_forwarding(fwd_port, buf, + fwd_host_port); + logit("Forwarding port."); + } + out: signal(SIGINT, handler); enter_raw_mode(); @@ -839,13 +1130,9 @@ static void client_channel_closed(int id, void *arg) { - if (id != session_ident) - error("client_channel_closed: id %d != session_ident %d", - id, session_ident); channel_cancel_cleanup(id); session_closed = 1; - if (in_raw_mode()) - leave_raw_mode(); + leave_raw_mode(); } /* @@ -860,7 +1147,8 @@ { fd_set *readset = NULL, *writeset = NULL; double start_time, total_time; - int max_fd = 0, max_fd2 = 0, len, rekeying = 0, nalloc = 0; + int max_fd = 0, max_fd2 = 0, len, rekeying = 0; + u_int nalloc = 0; char buf[100]; debug("Entering interactive session."); @@ -876,6 +1164,8 @@ 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 (!compat20) { /* enable nonblocking unless tty */ @@ -993,6 +1283,9 @@ /* Buffer input from the connection. */ client_process_net_input(readset); + /* Accept control connections. */ + client_process_control(readset); + if (quit_pending) break; @@ -1034,12 +1327,19 @@ if (!isatty(fileno(stderr))) unset_nonblock(fileno(stderr)); - if (received_signal) { - if (in_non_blocking_mode) /* XXX */ - leave_non_blocking(); - fatal("Killed by signal %d.", (int) received_signal); + /* + * If there was no shell or command requested, there will be no remote + * exit status to be returned. In that case, clear error code if the + * connection was deliberately terminated at this end. + */ + if (no_shell_flag && received_signal == SIGTERM) { + received_signal = 0; + exit_status = 0; } + if (received_signal) + fatal("Killed by signal %d.", (int) received_signal); + /* * In interactive mode (with pseudo tty) display a message indicating * that the connection has been closed. @@ -1131,7 +1431,47 @@ /* Flag that we want to exit. */ quit_pending = 1; } +static void +client_input_agent_open(int type, u_int32_t seq, void *ctxt) +{ + Channel *c = NULL; + int remote_id, sock; + /* Read the remote channel number from the message. */ + remote_id = packet_get_int(); + packet_check_eom(); + + /* + * Get a connection to the local authentication agent (this may again + * get forwarded). + */ + sock = ssh_get_authentication_socket(); + + /* + * If we could not connect the agent, send an error message back to + * the server. This should never happen unless the agent dies, + * because authentication forwarding is only enabled if we have an + * agent. + */ + if (sock >= 0) { + c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, + -1, 0, 0, 0, "authentication agent connection", 1); + c->remote_id = remote_id; + c->force_drain = 1; + } + if (c == NULL) { + packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); + packet_put_int(remote_id); + } else { + /* Send a confirmation to the remote host. */ + debug("Forwarding authentication connection."); + packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); + packet_put_int(remote_id); + packet_put_int(c->self); + } + packet_send(); +} + static Channel * client_request_forwarded_tcpip(const char *request_type, int rchan) { @@ -1277,7 +1617,7 @@ client_input_channel_req(int type, u_int32_t seq, void *ctxt) { Channel *c = NULL; - int id, reply, success = 0; + int exitval, id, reply, success = 0; char *rtype; id = packet_get_int(); @@ -1287,24 +1627,28 @@ debug("client_input_channel_req: channel %d rtype %s reply %d", id, rtype, reply); - if (session_ident == -1) { - error("client_input_channel_req: no channel %d", session_ident); - } else if (id != session_ident) { - error("client_input_channel_req: channel %d: wrong channel: %d", - session_ident, id); - } - c = channel_lookup(id); - if (c == NULL) { + if (id == -1) { + error("client_input_channel_req: request for channel -1"); + } else if ((c = channel_lookup(id)) == NULL) { error("client_input_channel_req: channel %d: unknown channel", id); } else if (strcmp(rtype, "exit-status") == 0) { - success = 1; - exit_status = packet_get_int(); + exitval = packet_get_int(); + if (id == session_ident) { + success = 1; + exit_status = exitval; + } else if (c->ctl_fd == -1) { + error("client_input_channel_req: unexpected channel %d", + session_ident); + } else { + atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval)); + success = 1; + } packet_check_eom(); } if (reply) { packet_start(success ? SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); - packet_put_int(c->remote_id); + packet_put_int(id); packet_send(); } xfree(rtype); @@ -1318,7 +1662,8 @@ rtype = packet_get_string(NULL); want_reply = packet_get_char(); - debug("client_input_global_request: rtype %s want_reply %d", rtype, want_reply); + debug("client_input_global_request: rtype %s want_reply %d", + rtype, want_reply); if (want_reply) { packet_start(success ? SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); @@ -1328,6 +1673,97 @@ xfree(rtype); } +void +client_session2_setup(int id, int want_tty, int want_subsystem, + const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env, + dispatch_fn *subsys_repl) +{ + int len; + + debug2("%s: id %d", __func__, id); + + if (want_tty) { + struct winsize ws; + struct termios tio; + + /* Store window size in the packet. */ + if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) + memset(&ws, 0, sizeof(ws)); + + channel_request_start(id, "pty-req", 0); + packet_put_cstring(term != NULL ? term : ""); + 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(-1, tiop != NULL ? tiop : &tio); + packet_send(); + /* XXX wait for reply */ + } + + /* Transfer any environment variables from client to server */ + if (options.num_send_env != 0 && env != NULL) { + int i, j, matched; + char *name, *val; + + debug("Sending environment."); + for (i = 0; env[i] != NULL; i++) { + /* Split */ + name = xstrdup(env[i]); + if ((val = strchr(name, '=')) == NULL) { + free(name); + continue; + } + *val++ = '\0'; + + matched = 0; + for (j = 0; j < options.num_send_env; j++) { + if (match_pattern(name, options.send_env[j])) { + matched = 1; + break; + } + } + if (!matched) { + debug3("Ignored env %s", name); + free(name); + continue; + } + + debug("Sending env %s = %s", name, val); + channel_request_start(id, "env", 0); + packet_put_cstring(name); + packet_put_cstring(val); + packet_send(); + free(name); + } + } + + len = buffer_len(cmd); + if (len > 0) { + if (len > 900) + len = 900; + if (want_subsystem) { + debug("Sending subsystem: %.*s", len, (u_char*)buffer_ptr(cmd)); + channel_request_start(id, "subsystem", subsys_repl != NULL); + if (subsys_repl != NULL) { + /* register callback for reply */ + /* XXX we assume that client_loop has already been called */ + dispatch_set(SSH2_MSG_CHANNEL_FAILURE, subsys_repl); + dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, subsys_repl); + } + } else { + debug("Sending command: %.*s", len, (u_char*)buffer_ptr(cmd)); + channel_request_start(id, "exec", 0); + } + packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); + packet_send(); + } else { + channel_request_start(id, "shell", 0); + packet_send(); + } +} + static void client_init_dispatch_20(void) { @@ -1366,7 +1802,7 @@ dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data); dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ? - &auth_input_open_request : &deny_input_open); + &client_input_agent_open : &deny_input_open); dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ? &x11_input_open : &deny_input_open); } @@ -1386,4 +1822,15 @@ client_init_dispatch_13(); else client_init_dispatch_15(); +} + +/* client specific fatal cleanup */ +void +cleanup_exit(int i) +{ + leave_raw_mode(); + leave_non_blocking(); + if (options.control_path != NULL && control_fd != -1) + unlink(options.control_path); + _exit(i); }