/* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved * The main loop for the interactive session (client side). * * As far as I am concerned, the code I have written for this software * can be used freely for any purpose. Any derived versions of this * software must be clearly marked as such, and if the derived work is * incompatible with the protocol description in the RFC file, it must be * called by a name other than "ssh" or "Secure Shell". * * * Copyright (c) 1999 Theo de Raadt. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * * SSH2 support added by Markus Friedl. * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include "includes.h" RCSID("$OpenBSD: clientloop.c,v 1.104 2002/08/22 19:38:42 stevesk Exp $"); #include "ssh.h" #include "ssh1.h" #include "ssh2.h" #include "xmalloc.h" #include "packet.h" #include "buffer.h" #include "compat.h" #include "channels.h" #include "dispatch.h" #include "buffer.h" #include "bufaux.h" #include "key.h" #include "kex.h" #include "log.h" #include "readconf.h" #include "clientloop.h" #include "authfd.h" #include "atomicio.h" #include "sshtty.h" #include "misc.h" #include "readpass.h" /* import options */ extern Options options; /* Flag indicating that stdin should be redirected from /dev/null. */ extern int stdin_null_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 * configuration file. */ extern char *host; /* * Flag to indicate that we have received a window change signal which has * not yet been processed. This will cause a message indicating the new * window size to be sent to the server a little later. This is volatile * because this is updated in a signal handler. */ static volatile sig_atomic_t received_window_change_signal = 0; static volatile sig_atomic_t received_signal = 0; /* Flag indicating whether the user\'s terminal is in non-blocking mode. */ static int in_non_blocking_mode = 0; /* Common data for the client loop code. */ static int quit_pending; /* Set to non-zero to quit the client loop. */ static int escape_char; /* Escape character. */ static int escape_pending; /* Last character was the escape character */ static int last_was_cr; /* Last character was a newline. */ static int exit_status; /* Used to store the exit status of the command. */ static int stdin_eof; /* EOF has been encountered on standard error. */ static Buffer stdin_buffer; /* Buffer for stdin data. */ static Buffer stdout_buffer; /* Buffer for stdout data. */ static Buffer stderr_buffer; /* Buffer for stderr data. */ static u_long stdin_bytes, stdout_bytes, stderr_bytes; static u_int buffer_high;/* Soft max buffer size. */ 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 void client_init_dispatch(void); int session_ident = -1; /*XXX*/ extern Kex *xxx_kex; /* Restores stdin to blocking mode. */ static void 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); } } /* Puts stdin terminal in non-blocking mode. */ static void 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); } /* * Signal handler for the window change signal (SIGWINCH). This just sets a * flag indicating that the window has changed. */ static void window_change_handler(int sig) { received_window_change_signal = 1; signal(SIGWINCH, window_change_handler); } /* * Signal handler for signals that cause the program to terminate. These * signals must be trapped to restore terminal modes. */ static void signal_handler(int sig) { received_signal = sig; quit_pending = 1; } /* * Returns current time in seconds from Jan 1, 1970 with the maximum * available resolution. */ static double get_current_time(void) { struct timeval tv; gettimeofday(&tv, NULL); return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0; } /* * This is called when the interactive is entered. This checks if there is * an EOF coming on stdin. We must check this explicitly, as select() does * not appear to wake up when redirecting from /dev/null. */ static void client_check_initial_eof_on_stdin(void) { int len; char buf[1]; /* * If standard input is to be "redirected from /dev/null", we simply * mark that we have seen an EOF and send an EOF message to the * server. Otherwise, we try to read a single character; it appears * that for some files, such /dev/null, select() never wakes up for * read for this descriptor, which means that we never get EOF. This * way we will get the EOF if stdin comes from /dev/null or similar. */ if (stdin_null_flag) { /* Fake EOF on stdin. */ debug("Sending eof."); stdin_eof = 1; packet_start(SSH_CMSG_EOF); packet_send(); } else { enter_non_blocking(); /* Check for immediate EOF on stdin. */ len = read(fileno(stdin), buf, 1); if (len == 0) { /* EOF. Record that we have seen it and send EOF to server. */ debug("Sending eof."); stdin_eof = 1; packet_start(SSH_CMSG_EOF); packet_send(); } else if (len > 0) { /* * Got data. We must store the data in the buffer, * and also process it as an escape character if * appropriate. */ if ((u_char) buf[0] == escape_char) escape_pending = 1; else buffer_append(&stdin_buffer, buf, 1); } leave_non_blocking(); } } /* * Make packets from buffered stdin data, and buffer them for sending to the * connection. */ static void client_make_packets_from_stdin_data(void) { u_int len; /* Send buffered stdin data to the server. */ while (buffer_len(&stdin_buffer) > 0 && packet_not_very_much_data_to_write()) { len = buffer_len(&stdin_buffer); /* Keep the packets at reasonable size. */ if (len > packet_get_maxsize()) len = packet_get_maxsize(); packet_start(SSH_CMSG_STDIN_DATA); packet_put_string(buffer_ptr(&stdin_buffer), len); packet_send(); buffer_consume(&stdin_buffer, len); stdin_bytes += len; /* If we have a pending EOF, send it now. */ if (stdin_eof && buffer_len(&stdin_buffer) == 0) { packet_start(SSH_CMSG_EOF); packet_send(); } } } /* * Checks if the client window has changed, and sends a packet about it to * the server if so. The actual change is detected elsewhere (by a software * interrupt on Unix); this just checks the flag and sends a message if * appropriate. */ static void client_check_window_change(void) { struct winsize ws; if (! received_window_change_signal) return; /** 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(); } else { packet_start(SSH_CMSG_WINDOW_SIZE); packet_put_int(ws.ws_row); packet_put_int(ws.ws_col); packet_put_int(ws.ws_xpixel); packet_put_int(ws.ws_ypixel); 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) { /* Add any selections by the channel mechanism. */ channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, rekeying); if (!compat20) { /* Read from the connection, unless our buffers are full. */ if (buffer_len(&stdout_buffer) < buffer_high && buffer_len(&stderr_buffer) < buffer_high && channel_not_very_much_buffered_data()) FD_SET(connection_in, *readsetp); /* * Read from stdin, unless we have seen EOF or have very much * buffered data to send to the server. */ if (!stdin_eof && packet_not_very_much_data_to_write()) FD_SET(fileno(stdin), *readsetp); /* Select stdout/stderr if have data in buffer. */ if (buffer_len(&stdout_buffer) > 0) FD_SET(fileno(stdout), *writesetp); if (buffer_len(&stderr_buffer) > 0) FD_SET(fileno(stderr), *writesetp); } else { /* channel_prepare_select could have closed the last channel */ if (session_closed && !channel_still_open() && !packet_have_data_to_write()) { /* clear mask since we did not call select() */ memset(*readsetp, 0, *nallocp); memset(*writesetp, 0, *nallocp); return; } else { FD_SET(connection_in, *readsetp); } } /* Select server connection if have data to write to the server. */ if (packet_have_data_to_write()) FD_SET(connection_out, *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. */ if (select((*maxfdp)+1, *readsetp, *writesetp, NULL, NULL) < 0) { char buf[100]; /* * We have to clear the select masks, because we return. * We have to return, because the mainloop checks for the flags * set by the signal handlers. */ memset(*readsetp, 0, *nallocp); memset(*writesetp, 0, *nallocp); if (errno == EINTR) return; /* Note: we might still have data in the buffers. */ snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); buffer_append(&stderr_buffer, buf, strlen(buf)); quit_pending = 1; } } static void client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr) { struct winsize oldws, newws; /* Flush stdout and stderr buffers. */ if (buffer_len(bout) > 0) atomicio(write, fileno(stdout), buffer_ptr(bout), buffer_len(bout)); if (buffer_len(berr) > 0) atomicio(write, fileno(stderr), buffer_ptr(berr), buffer_len(berr)); leave_raw_mode(); /* * Free (and clear) the buffer to reduce the amount of data that gets * written to swap. */ buffer_free(bin); buffer_free(bout); buffer_free(berr); /* Save old window size. */ ioctl(fileno(stdin), TIOCGWINSZ, &oldws); /* Send the suspend signal to the program itself. */ kill(getpid(), SIGTSTP); /* Check if the window size has changed. */ if (ioctl(fileno(stdin), TIOCGWINSZ, &newws) >= 0 && (oldws.ws_row != newws.ws_row || oldws.ws_col != newws.ws_col || oldws.ws_xpixel != newws.ws_xpixel || oldws.ws_ypixel != newws.ws_ypixel)) received_window_change_signal = 1; /* OK, we have been continued by the user. Reinitialize buffers. */ buffer_init(bin); buffer_init(bout); buffer_init(berr); enter_raw_mode(); } static void client_process_net_input(fd_set * readset) { int len; char buf[8192]; /* * Read input from the server, and add any such data to the buffer of * the packet subsystem. */ if (FD_ISSET(connection_in, readset)) { /* Read as much as possible. */ len = read(connection_in, buf, sizeof(buf)); if (len == 0) { /* Received EOF. The remote host has closed the connection. */ snprintf(buf, sizeof buf, "Connection to %.300s closed by remote host.\r\n", host); buffer_append(&stderr_buffer, buf, strlen(buf)); quit_pending = 1; return; } /* * There is a kernel bug on Solaris that causes select to * sometimes wake up even though there is no data available. */ if (len < 0 && (errno == EAGAIN || errno == EINTR)) len = 0; if (len < 0) { /* An error has encountered. Perhaps there is a network problem. */ snprintf(buf, sizeof buf, "Read from remote host %.300s: %.100s\r\n", host, strerror(errno)); buffer_append(&stderr_buffer, buf, strlen(buf)); quit_pending = 1; return; } packet_process_incoming(buf, len); } } 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')) { log("Invalid command."); goto out; } if (s[1] == 'L') local = 1; if (!local && !compat20) { log("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) { log("Bad forwarding specification."); goto out; } if ((fwd_port = a2port(sfwd_port)) == 0 || (fwd_host_port = a2port(sfwd_host_port)) == 0) { log("Bad forwarding port(s)."); goto out; } if (local) { if (channel_setup_local_fwd_listener(fwd_port, buf, fwd_host_port, options.gateway_ports) < 0) { log("Port forwarding failed."); goto out; } } else channel_request_remote_forwarding(fwd_port, buf, fwd_host_port); log("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) { char string[1024]; pid_t pid; int bytes = 0; u_int i; u_char ch; char *s; for (i = 0; i < len; i++) { /* Get one character at a time. */ ch = buf[i]; if (escape_pending) { /* We have previously seen an escape character. */ /* Clear the flag now. */ escape_pending = 0; /* Process the escaped character. */ switch (ch) { case '.': /* Terminate the connection. */ snprintf(string, sizeof string, "%c.\r\n", escape_char); buffer_append(berr, string, strlen(string)); quit_pending = 1; return -1; case 'Z' - 64: /* Suspend the program. */ /* Print a message to that effect to the user. */ snprintf(string, sizeof string, "%c^Z [suspend ssh]\r\n", escape_char); buffer_append(berr, string, strlen(string)); /* Restore terminal modes and suspend. */ client_suspend_self(bin, bout, berr); /* We have been continued. */ continue; case 'R': if (compat20) { if (datafellows & SSH_BUG_NOREKEY) log("Server does not support re-keying"); else need_rekeying = 1; } continue; case '&': /* * Detach the program (continue to serve connections, * but put in background and no more new connections). */ /* Restore tty modes. */ leave_raw_mode(); /* Stop listening for new connections. */ channel_stop_listening(); snprintf(string, sizeof string, "%c& [backgrounded]\n", escape_char); buffer_append(berr, string, strlen(string)); /* Fork into background. */ pid = fork(); if (pid < 0) { error("fork: %.100s", strerror(errno)); continue; } if (pid != 0) { /* This is the parent. */ /* The parent just exits. */ exit(0); } /* The child continues serving connections. */ if (compat20) { buffer_append(bin, "\004", 1); /* fake EOF on stdin */ return -1; } else if (!stdin_eof) { /* * Sending SSH_CMSG_EOF alone does not always appear * to be enough. So we try to send an EOF character * first. */ packet_start(SSH_CMSG_STDIN_DATA); packet_put_string("\004", 1); packet_send(); /* Close stdin. */ stdin_eof = 1; if (buffer_len(bin) == 0) { packet_start(SSH_CMSG_EOF); packet_send(); } } continue; case '?': snprintf(string, sizeof string, "%c?\r\n\ Supported escape sequences:\r\n\ %c. - terminate connection\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); buffer_append(berr, string, strlen(string)); continue; case '#': snprintf(string, sizeof string, "%c#\r\n", escape_char); buffer_append(berr, string, strlen(string)); s = channel_open_message(); buffer_append(berr, s, strlen(s)); xfree(s); continue; case 'C': process_cmdline(); continue; default: if (ch != escape_char) { buffer_put_char(bin, escape_char); bytes++; } /* Escaped characters fall through here */ break; } } else { /* * The previous character was not an escape char. Check if this * is an escape. */ if (last_was_cr && ch == escape_char) { /* It is. Set the flag and continue to next character. */ escape_pending = 1; continue; } } /* * Normal character. Record whether it was a newline, * and append it to the buffer. */ last_was_cr = (ch == '\r' || ch == '\n'); buffer_put_char(bin, ch); bytes++; } return bytes; } static void client_process_input(fd_set * readset) { int len; char buf[8192]; /* Read input from stdin. */ if (FD_ISSET(fileno(stdin), readset)) { /* Read as much as possible. */ len = read(fileno(stdin), buf, sizeof(buf)); if (len < 0 && (errno == EAGAIN || errno == EINTR)) return; /* we'll try again later */ if (len <= 0) { /* * Received EOF or error. They are treated * similarly, except that an error message is printed * if it was an error condition. */ if (len < 0) { snprintf(buf, sizeof buf, "read: %.100s\r\n", strerror(errno)); buffer_append(&stderr_buffer, buf, strlen(buf)); } /* Mark that we have seen EOF. */ stdin_eof = 1; /* * Send an EOF message to the server unless there is * data in the buffer. If there is data in the * buffer, no message will be sent now. Code * elsewhere will send the EOF when the buffer * becomes empty if stdin_eof is set. */ if (buffer_len(&stdin_buffer) == 0) { packet_start(SSH_CMSG_EOF); packet_send(); } } else if (escape_char == SSH_ESCAPECHAR_NONE) { /* * Normal successful read, and no escape character. * Just append the data to buffer. */ buffer_append(&stdin_buffer, buf, len); } else { /* * Normal, successful read. But we have an escape character * and have to process the characters one by one. */ if (process_escapes(&stdin_buffer, &stdout_buffer, &stderr_buffer, buf, len) == -1) return; } } } static void client_process_output(fd_set * writeset) { int len; char buf[100]; /* Write buffered output to stdout. */ if (FD_ISSET(fileno(stdout), writeset)) { /* Write as much data as possible. */ len = write(fileno(stdout), buffer_ptr(&stdout_buffer), buffer_len(&stdout_buffer)); if (len <= 0) { if (errno == EINTR || errno == EAGAIN) len = 0; else { /* * An error or EOF was encountered. Put an * error message to stderr buffer. */ snprintf(buf, sizeof buf, "write stdout: %.50s\r\n", strerror(errno)); buffer_append(&stderr_buffer, buf, strlen(buf)); quit_pending = 1; return; } } /* Consume printed data from the buffer. */ buffer_consume(&stdout_buffer, len); stdout_bytes += len; } /* Write buffered output to stderr. */ if (FD_ISSET(fileno(stderr), writeset)) { /* Write as much data as possible. */ len = write(fileno(stderr), buffer_ptr(&stderr_buffer), buffer_len(&stderr_buffer)); if (len <= 0) { if (errno == EINTR || errno == EAGAIN) len = 0; else { /* EOF or error, but can't even print error message. */ quit_pending = 1; return; } } /* Consume printed characters from the buffer. */ buffer_consume(&stderr_buffer, len); stderr_bytes += len; } } /* * Get packets from the connection input buffer, and process them as long as * there are packets available. * * Any unknown packets received during the actual * session cause the session to terminate. This is * intended to make debugging easier since no * confirmations are sent. Any compatible protocol * extensions must be negotiated during the * preparatory phase. */ static void client_process_buffered_input_packets(void) { dispatch_run(DISPATCH_NONBLOCK, &quit_pending, compat20 ? xxx_kex : NULL); } /* scan buf[] for '~' before sending data to the peer */ static int simple_escape_filter(Channel *c, char *buf, int len) { /* XXX we assume c->extended is writeable */ return process_escapes(&c->input, &c->output, &c->extended, buf, len); } 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(); } /* * Implements the interactive session with the server. This is called after * the user has been authenticated, and a command has been started on the * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character * used as an escape character for terminating or suspending the session. */ int client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) { fd_set *readset = NULL, *writeset = NULL; double start_time, total_time; int max_fd = 0, max_fd2 = 0, len, rekeying = 0, nalloc = 0; char buf[100]; debug("Entering interactive session."); start_time = get_current_time(); /* Initialize variables. */ escape_pending = 0; last_was_cr = 1; exit_status = -1; stdin_eof = 0; buffer_high = 64 * 1024; connection_in = packet_get_connection_in(); connection_out = packet_get_connection_out(); max_fd = MAX(connection_in, connection_out); if (!compat20) { /* enable nonblocking unless tty */ if (!isatty(fileno(stdin))) set_nonblock(fileno(stdin)); if (!isatty(fileno(stdout))) set_nonblock(fileno(stdout)); if (!isatty(fileno(stderr))) set_nonblock(fileno(stderr)); max_fd = MAX(max_fd, fileno(stdin)); max_fd = MAX(max_fd, fileno(stdout)); max_fd = MAX(max_fd, fileno(stderr)); } stdin_bytes = 0; stdout_bytes = 0; stderr_bytes = 0; quit_pending = 0; escape_char = escape_char_arg; /* Initialize buffers. */ buffer_init(&stdin_buffer); buffer_init(&stdout_buffer); buffer_init(&stderr_buffer); client_init_dispatch(); /* Set signal handlers to restore non-blocking mode. */ signal(SIGINT, signal_handler); signal(SIGQUIT, signal_handler); signal(SIGTERM, signal_handler); if (have_pty) signal(SIGWINCH, window_change_handler); if (have_pty) enter_raw_mode(); if (compat20) { session_ident = ssh2_chan_id; if (escape_char != SSH_ESCAPECHAR_NONE) channel_register_filter(session_ident, simple_escape_filter); if (session_ident != -1) channel_register_cleanup(session_ident, client_channel_closed); } else { /* Check if we should immediately send eof on stdin. */ client_check_initial_eof_on_stdin(); } /* Main loop of the client for the interactive session mode. */ while (!quit_pending) { /* Process buffered packets sent by the server. */ client_process_buffered_input_packets(); if (compat20 && session_closed && !channel_still_open()) break; rekeying = (xxx_kex != NULL && !xxx_kex->done); if (rekeying) { debug("rekeying in progress"); } else { /* * Make packets of buffered stdin data, and buffer * them for sending to the server. */ if (!compat20) client_make_packets_from_stdin_data(); /* * Make packets from buffered channel data, and * enqueue them for sending to the server. */ if (packet_not_very_much_data_to_write()) channel_output_poll(); /* * Check if the window size has changed, and buffer a * message about it to the server if so. */ client_check_window_change(); if (quit_pending) break; } /* * Wait until we have something to do (something becomes * available on one of the descriptors). */ max_fd2 = max_fd; client_wait_until_can_do_something(&readset, &writeset, &max_fd2, &nalloc, rekeying); if (quit_pending) break; /* Do channel operations unless rekeying in progress. */ if (!rekeying) { channel_after_select(readset, writeset); if (need_rekeying) { debug("user requests rekeying"); xxx_kex->done = 0; kex_send_kexinit(xxx_kex); need_rekeying = 0; } } /* Buffer input from the connection. */ client_process_net_input(readset); if (quit_pending) break; if (!compat20) { /* Buffer data from stdin */ client_process_input(readset); /* * Process output to stdout and stderr. Output to * the connection is processed elsewhere (above). */ client_process_output(writeset); } /* Send as much buffered packet data as possible to the sender. */ if (FD_ISSET(connection_out, writeset)) packet_write_poll(); } if (readset) xfree(readset); if (writeset) xfree(writeset); /* Terminate the session. */ /* Stop watching for window change. */ if (have_pty) signal(SIGWINCH, SIG_DFL); channel_free_all(); if (have_pty) leave_raw_mode(); /* restore blocking io */ if (!isatty(fileno(stdin))) unset_nonblock(fileno(stdin)); if (!isatty(fileno(stdout))) unset_nonblock(fileno(stdout)); 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); } /* * In interactive mode (with pseudo tty) display a message indicating * that the connection has been closed. */ if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { snprintf(buf, sizeof buf, "Connection to %.64s closed.\r\n", host); buffer_append(&stderr_buffer, buf, strlen(buf)); } /* Output any buffered data for stdout. */ while (buffer_len(&stdout_buffer) > 0) { len = write(fileno(stdout), buffer_ptr(&stdout_buffer), buffer_len(&stdout_buffer)); if (len <= 0) { error("Write failed flushing stdout buffer."); break; } buffer_consume(&stdout_buffer, len); stdout_bytes += len; } /* Output any buffered data for stderr. */ while (buffer_len(&stderr_buffer) > 0) { len = write(fileno(stderr), buffer_ptr(&stderr_buffer), buffer_len(&stderr_buffer)); if (len <= 0) { error("Write failed flushing stderr buffer."); break; } buffer_consume(&stderr_buffer, len); stderr_bytes += len; } /* Clear and free any buffers. */ memset(buf, 0, sizeof(buf)); buffer_free(&stdin_buffer); buffer_free(&stdout_buffer); buffer_free(&stderr_buffer); /* Report bytes transferred, and transfer rates. */ total_time = get_current_time() - start_time; debug("Transferred: stdin %lu, stdout %lu, stderr %lu bytes in %.1f seconds", stdin_bytes, stdout_bytes, stderr_bytes, total_time); if (total_time > 0) debug("Bytes per second: stdin %.1f, stdout %.1f, stderr %.1f", stdin_bytes / total_time, stdout_bytes / total_time, stderr_bytes / total_time); /* Return the exit status of the program. */ debug("Exit status %d", exit_status); return exit_status; } /*********/ static void client_input_stdout_data(int type, u_int32_t seq, void *ctxt) { u_int data_len; char *data = packet_get_string(&data_len); packet_check_eom(); buffer_append(&stdout_buffer, data, data_len); memset(data, 0, data_len); xfree(data); } static void client_input_stderr_data(int type, u_int32_t seq, void *ctxt) { u_int data_len; char *data = packet_get_string(&data_len); packet_check_eom(); buffer_append(&stderr_buffer, data, data_len); memset(data, 0, data_len); xfree(data); } static void client_input_exit_status(int type, u_int32_t seq, void *ctxt) { exit_status = packet_get_int(); packet_check_eom(); /* Acknowledge the exit. */ packet_start(SSH_CMSG_EXIT_CONFIRMATION); packet_send(); /* * Must wait for packet to be sent since we are * exiting the loop. */ packet_write_wait(); /* Flag that we want to exit. */ quit_pending = 1; } static Channel * client_request_forwarded_tcpip(const char *request_type, int rchan) { Channel *c = NULL; char *listen_address, *originator_address; int listen_port, originator_port; int sock; /* Get rest of the packet */ listen_address = packet_get_string(NULL); listen_port = packet_get_int(); originator_address = packet_get_string(NULL); originator_port = packet_get_int(); packet_check_eom(); debug("client_request_forwarded_tcpip: listen %s port %d, originator %s port %d", listen_address, listen_port, originator_address, originator_port); sock = channel_connect_by_listen_address(listen_port); if (sock < 0) { xfree(originator_address); xfree(listen_address); return NULL; } c = channel_new("forwarded-tcpip", SSH_CHANNEL_CONNECTING, sock, sock, -1, CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_WINDOW_DEFAULT, 0, xstrdup(originator_address), 1); xfree(originator_address); xfree(listen_address); return c; } static Channel * client_request_x11(const char *request_type, int rchan) { Channel *c = NULL; char *originator; int originator_port; int sock; if (!options.forward_x11) { error("Warning: ssh server tried X11 forwarding."); error("Warning: this is probably a break in attempt by a malicious server."); return NULL; } originator = packet_get_string(NULL); if (datafellows & SSH_BUG_X11FWD) { debug2("buggy server: x11 request w/o originator_port"); originator_port = 0; } else { originator_port = packet_get_int(); } packet_check_eom(); /* XXX check permission */ debug("client_request_x11: request from %s %d", originator, originator_port); xfree(originator); sock = x11_connect_display(); if (sock < 0) 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); c->force_drain = 1; return c; } static Channel * client_request_agent(const char *request_type, int rchan) { Channel *c = NULL; int sock; if (!options.forward_agent) { error("Warning: ssh server tried agent forwarding."); error("Warning: this is probably a break in attempt by a malicious server."); return NULL; } sock = ssh_get_authentication_socket(); if (sock < 0) return NULL; 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); c->force_drain = 1; return c; } /* XXXX move to generic input handler */ static void client_input_channel_open(int type, u_int32_t seq, void *ctxt) { Channel *c = NULL; char *ctype; int rchan; u_int rmaxpack, rwindow, len; ctype = packet_get_string(&len); rchan = packet_get_int(); rwindow = packet_get_int(); rmaxpack = packet_get_int(); debug("client_input_channel_open: ctype %s rchan %d win %d max %d", ctype, rchan, rwindow, rmaxpack); if (strcmp(ctype, "forwarded-tcpip") == 0) { c = client_request_forwarded_tcpip(ctype, rchan); } else if (strcmp(ctype, "x11") == 0) { c = client_request_x11(ctype, rchan); } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { c = client_request_agent(ctype, rchan); } /* XXX duplicate : */ if (c != NULL) { debug("confirm %s", ctype); c->remote_id = rchan; c->remote_window = rwindow; c->remote_maxpacket = rmaxpack; if (c->type != SSH_CHANNEL_CONNECTING) { packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); packet_put_int(c->remote_id); packet_put_int(c->self); packet_put_int(c->local_window); packet_put_int(c->local_maxpacket); packet_send(); } } else { debug("failure %s", ctype); packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); packet_put_int(rchan); packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); if (!(datafellows & SSH_BUG_OPENFAILURE)) { packet_put_cstring("open failed"); packet_put_cstring(""); } packet_send(); } xfree(ctype); } static void client_input_channel_req(int type, u_int32_t seq, void *ctxt) { Channel *c = NULL; int id, reply, success = 0; char *rtype; id = packet_get_int(); rtype = packet_get_string(NULL); reply = packet_get_char(); 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) { error("client_input_channel_req: channel %d: unknown channel", id); } else if (strcmp(rtype, "exit-status") == 0) { success = 1; exit_status = packet_get_int(); packet_check_eom(); } if (reply) { packet_start(success ? SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); packet_put_int(c->remote_id); packet_send(); } 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); dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 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) { dispatch_init(NULL); dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status); dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data); 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); dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ? &x11_input_open : &deny_input_open); } static void client_init_dispatch_15(void) { client_init_dispatch_13(); dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose); } static void client_init_dispatch(void) { if (compat20) client_init_dispatch_20(); else if (compat13) client_init_dispatch_13(); else client_init_dispatch_15(); }