X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/7819b5c305d08e18530a4cc4ebc3ee0c0cefadff..f9e4952c0d45a2afdc9267c8cc9500462a82ad11:/clientloop.c diff --git a/clientloop.c b/clientloop.c index e66b60cf..626b29a5 100644 --- a/clientloop.c +++ b/clientloop.c @@ -59,7 +59,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: clientloop.c,v 1.94 2001/12/28 15:06:00 markus Exp $"); +RCSID("$OpenBSD: clientloop.c,v 1.117 2003/12/16 15:49:51 markus Exp $"); #include "ssh.h" #include "ssh1.h" @@ -81,6 +81,7 @@ RCSID("$OpenBSD: clientloop.c,v 1.94 2001/12/28 15:06:00 markus Exp $"); #include "atomicio.h" #include "sshtty.h" #include "misc.h" +#include "readpass.h" /* import options */ extern Options options; @@ -88,6 +89,9 @@ extern Options options; /* 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; + /* * 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 @@ -123,6 +127,7 @@ static int connection_in; /* Connection to server (input). */ 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; @@ -138,7 +143,6 @@ leave_non_blocking(void) if (in_non_blocking_mode) { (void) fcntl(fileno(stdin), F_SETFL, 0); in_non_blocking_mode = 0; - fatal_remove_cleanup((void (*) (void *)) leave_non_blocking, NULL); } } @@ -149,7 +153,6 @@ 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); } /* @@ -311,6 +314,24 @@ client_check_window_change(void) } } +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). @@ -320,6 +341,9 @@ static void client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp, 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); @@ -361,13 +385,18 @@ client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, /* * 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]; /* @@ -384,7 +413,8 @@ client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, 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 @@ -394,9 +424,9 @@ client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr) /* Flush stdout and stderr buffers. */ if (buffer_len(bout) > 0) - atomicio(write, fileno(stdout), buffer_ptr(bout), buffer_len(bout)); + atomicio(vwrite, fileno(stdout), buffer_ptr(bout), buffer_len(bout)); if (buffer_len(berr) > 0) - atomicio(write, fileno(stderr), buffer_ptr(berr), buffer_len(berr)); + atomicio(vwrite, fileno(stderr), buffer_ptr(berr), buffer_len(berr)); leave_raw_mode(); @@ -470,6 +500,67 @@ client_process_net_input(fd_set * readset) } } +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 local = 0; + + leave_raw_mode(); + handler = signal(SIGINT, SIG_IGN); + cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); + if (s == NULL) + goto out; + while (*s && isspace(*s)) + s++; + if (*s == 0) + goto out; + if (strlen(s) < 2 || s[0] != '-' || !(s[1] == 'L' || s[1] == 'R')) { + logit("Invalid command."); + goto out; + } + if (s[1] == 'L') + local = 1; + if (!local && !compat20) { + logit("Not supported for SSH protocol version 1."); + goto out; + } + s += 2; + 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."); + goto out; + } + } else + channel_request_remote_forwarding(fwd_port, buf, + fwd_host_port); + logit("Forwarding port."); +out: + signal(SIGINT, handler); + enter_raw_mode(); + if (cmd) + xfree(cmd); +} + /* process the characters one by one */ static int process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len) @@ -512,10 +603,23 @@ process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len) /* We have been continued. */ continue; + case 'B': + if (compat20) { + snprintf(string, sizeof string, + "%cB\r\n", escape_char); + buffer_append(berr, string, + strlen(string)); + channel_request_start(session_ident, + "break", 0); + packet_put_int(1000); + packet_send(); + } + continue; + case 'R': if (compat20) { if (datafellows & SSH_BUG_NOREKEY) - log("Server does not support re-keying"); + logit("Server does not support re-keying"); else need_rekeying = 1; } @@ -573,15 +677,19 @@ process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len) snprintf(string, sizeof string, "%c?\r\n\ Supported escape sequences:\r\n\ -~. - terminate connection\r\n\ -~R - Request rekey (SSH protocol 2 only)\r\n\ -~^Z - suspend ssh\r\n\ -~# - list forwarded connections\r\n\ -~& - background ssh (when waiting for connections to terminate)\r\n\ -~? - this message\r\n\ -~~ - send the escape character by typing it twice\r\n\ +%c. - terminate connection\r\n\ +%cB - send a BREAK to the remote system\r\n\ +%cC - open a command line\r\n\ +%cR - Request rekey (SSH protocol 2 only)\r\n\ +%c^Z - suspend ssh\r\n\ +%c# - list forwarded connections\r\n\ +%c& - background ssh (when waiting for connections to terminate)\r\n\ +%c? - this message\r\n\ +%c%c - send the escape character by typing it twice\r\n\ (Note that escapes are only recognized immediately after newline.)\r\n", - escape_char); + escape_char, escape_char, escape_char, escape_char, + escape_char, escape_char, escape_char, escape_char, + escape_char, escape_char, escape_char); buffer_append(berr, string, strlen(string)); continue; @@ -593,6 +701,10 @@ Supported escape sequences:\r\n\ xfree(s); continue; + case 'C': + process_cmdline(); + continue; + default: if (ch != escape_char) { buffer_put_char(bin, escape_char); @@ -761,8 +873,7 @@ client_channel_closed(int id, void *arg) id, session_ident); channel_cancel_cleanup(id); session_closed = 1; - if (in_raw_mode()) - leave_raw_mode(); + leave_raw_mode(); } /* @@ -819,10 +930,16 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) client_init_dispatch(); - /* Set signal handlers to restore non-blocking mode. */ - signal(SIGINT, signal_handler); - signal(SIGQUIT, signal_handler); - signal(SIGTERM, signal_handler); + /* + * Set signal handlers, (e.g. to restore non-blocking mode) + * but don't overwrite SIG_IGN, matches behaviour from rsh(1) + */ + if (signal(SIGINT, SIG_IGN) != SIG_IGN) + signal(SIGINT, signal_handler); + if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) + signal(SIGQUIT, signal_handler); + if (signal(SIGTERM, SIG_IGN) != SIG_IGN) + signal(SIGTERM, signal_handler); if (have_pty) signal(SIGWINCH, window_change_handler); @@ -893,9 +1010,8 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) /* Do channel operations unless rekeying in progress. */ if (!rekeying) { channel_after_select(readset, writeset); - - if (need_rekeying) { - debug("user requests rekeying"); + if (need_rekeying || packet_need_rekeying()) { + debug("need rekeying"); xxx_kex->done = 0; kex_send_kexinit(xxx_kex); need_rekeying = 0; @@ -946,12 +1062,19 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) 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. @@ -1043,11 +1166,51 @@ client_input_exit_status(int type, u_int32_t seq, void *ctxt) /* 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) { - Channel* c = NULL; + Channel *c = NULL; char *listen_address, *originator_address; int listen_port, originator_port; int sock; @@ -1071,17 +1234,13 @@ client_request_forwarded_tcpip(const char *request_type, int rchan) c = channel_new("forwarded-tcpip", SSH_CHANNEL_CONNECTING, sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, - xstrdup(originator_address), 1); - if (c == NULL) { - error("client_request_forwarded_tcpip: channel_new failed"); - close(sock); - } + originator_address, 1); xfree(originator_address); xfree(listen_address); return c; } -static Channel* +static Channel * client_request_x11(const char *request_type, int rchan) { Channel *c = NULL; @@ -1111,17 +1270,12 @@ client_request_x11(const char *request_type, int rchan) return NULL; c = channel_new("x11", SSH_CHANNEL_X11_OPEN, sock, sock, -1, - CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, - xstrdup("x11"), 1); - if (c == NULL) { - error("client_request_x11: channel_new failed"); - close(sock); - } + CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); c->force_drain = 1; return c; } -static Channel* +static Channel * client_request_agent(const char *request_type, int rchan) { Channel *c = NULL; @@ -1138,11 +1292,7 @@ client_request_agent(const char *request_type, int rchan) c = channel_new("authentication agent connection", SSH_CHANNEL_OPEN, sock, sock, -1, CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, - xstrdup("authentication agent connection"), 1); - if (c == NULL) { - error("client_request_agent: channel_new failed"); - close(sock); - } + "authentication agent connection", 1); c->force_drain = 1; return c; } @@ -1153,10 +1303,8 @@ client_input_channel_open(int type, u_int32_t seq, void *ctxt) { Channel *c = NULL; char *ctype; - u_int len; int rchan; - int rmaxpack; - int rwindow; + u_int rmaxpack, rwindow, len; ctype = packet_get_string(&len); rchan = packet_get_int(); @@ -1236,11 +1384,31 @@ client_input_channel_req(int type, u_int32_t seq, void *ctxt) } xfree(rtype); } +static void +client_input_global_request(int type, u_int32_t seq, void *ctxt) +{ + char *rtype; + int want_reply; + int success = 0; + + rtype = packet_get_string(NULL); + want_reply = packet_get_char(); + 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); + packet_send(); + packet_write_wait(); + } + xfree(rtype); +} static void client_init_dispatch_20(void) { dispatch_init(&dispatch_protocol_error); + dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); @@ -1250,9 +1418,14 @@ client_init_dispatch_20(void) dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); + dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); /* rekeying */ dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); + + /* global request reply messages */ + dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); + dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); } static void client_init_dispatch_13(void) @@ -1269,7 +1442,7 @@ client_init_dispatch_13(void) 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); } @@ -1290,3 +1463,12 @@ client_init_dispatch(void) else client_init_dispatch_15(); } + +/* client specific fatal cleanup */ +void +cleanup_exit(int i) +{ + leave_raw_mode(); + leave_non_blocking(); + _exit(i); +}