| /* $OpenBSD: clientloop.c,v 1.341 2020/02/26 01:31:47 dtucker Exp $ */ |
| /* |
| * Author: Tatu Ylonen <ylo@cs.hut.fi> |
| * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, 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" |
| |
| #include <sys/types.h> |
| #include <sys/ioctl.h> |
| #ifdef HAVE_SYS_STAT_H |
| # include <sys/stat.h> |
| #endif |
| #ifdef HAVE_SYS_TIME_H |
| # include <sys/time.h> |
| #endif |
| #include <sys/socket.h> |
| |
| #include <ctype.h> |
| #include <errno.h> |
| #ifdef HAVE_PATHS_H |
| #include <paths.h> |
| #endif |
| #include <signal.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <stdarg.h> |
| #include <termios.h> |
| #include <pwd.h> |
| #include <unistd.h> |
| #include <limits.h> |
| |
| #include "openbsd-compat/sys-queue.h" |
| #include "xmalloc.h" |
| #include "ssh.h" |
| #include "ssh2.h" |
| #include "packet.h" |
| #include "sshbuf.h" |
| #include "compat.h" |
| #include "channels.h" |
| #include "dispatch.h" |
| #include "sshkey.h" |
| #include "cipher.h" |
| #include "kex.h" |
| #include "myproposal.h" |
| #include "log.h" |
| #include "misc.h" |
| #include "readconf.h" |
| #include "clientloop.h" |
| #include "sshconnect.h" |
| #include "authfd.h" |
| #include "atomicio.h" |
| #include "sshpty.h" |
| #include "match.h" |
| #include "msg.h" |
| #include "ssherr.h" |
| #include "hostfile.h" |
| |
| /* import options */ |
| 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; |
| |
| /* Flag indicating that ssh should daemonise after authentication is complete */ |
| extern int fork_after_authentication_flag; |
| |
| /* Control socket */ |
| extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */ |
| |
| /* |
| * 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; |
| |
| /* |
| * If this field is not NULL, the ForwardAgent socket is this path and different |
| * instead of SSH_AUTH_SOCK. |
| */ |
| extern char *forward_agent_sock_path; |
| |
| /* |
| * 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; |
| |
| /* Time when backgrounded control master using ControlPersist should exit */ |
| static time_t control_persist_exit_time = 0; |
| |
| /* Common data for the client loop code. */ |
| volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ |
| static int last_was_cr; /* Last character was a newline. */ |
| static int exit_status; /* Used to store the command exit status. */ |
| static struct sshbuf *stderr_buffer; /* Used for final exit message. */ |
| 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; /* In SSH2: login session closed. */ |
| static u_int x11_refuse_time; /* If >0, refuse x11 opens after this time. */ |
| |
| static void client_init_dispatch(struct ssh *ssh); |
| int session_ident = -1; |
| |
| /* Track escape per proto2 channel */ |
| struct escape_filter_ctx { |
| int escape_pending; |
| int escape_char; |
| }; |
| |
| /* Context for channel confirmation replies */ |
| struct channel_reply_ctx { |
| const char *request_type; |
| int id; |
| enum confirm_action action; |
| }; |
| |
| /* Global request success/failure callbacks */ |
| /* XXX move to struct ssh? */ |
| struct global_confirm { |
| TAILQ_ENTRY(global_confirm) entry; |
| global_confirm_cb *cb; |
| void *ctx; |
| int ref_count; |
| }; |
| TAILQ_HEAD(global_confirms, global_confirm); |
| static struct global_confirms global_confirms = |
| TAILQ_HEAD_INITIALIZER(global_confirms); |
| |
| void ssh_process_session2_setup(int, int, int, struct sshbuf *); |
| |
| /* Restores stdin to blocking mode. */ |
| |
| static void |
| leave_non_blocking(void) |
| { |
| if (in_non_blocking_mode) { |
| unset_nonblock(fileno(stdin)); |
| in_non_blocking_mode = 0; |
| } |
| } |
| |
| /* |
| * Signal handler for the window change signal (SIGWINCH). This just sets a |
| * flag indicating that the window has changed. |
| */ |
| /*ARGSUSED */ |
| static void |
| window_change_handler(int sig) |
| { |
| received_window_change_signal = 1; |
| } |
| |
| /* |
| * Signal handler for signals that cause the program to terminate. These |
| * signals must be trapped to restore terminal modes. |
| */ |
| /*ARGSUSED */ |
| static void |
| signal_handler(int sig) |
| { |
| received_signal = sig; |
| quit_pending = 1; |
| } |
| |
| /* |
| * Sets control_persist_exit_time to the absolute time when the |
| * backgrounded control master should exit due to expiry of the |
| * ControlPersist timeout. Sets it to 0 if we are not a backgrounded |
| * control master process, or if there is no ControlPersist timeout. |
| */ |
| static void |
| set_control_persist_exit_time(struct ssh *ssh) |
| { |
| if (muxserver_sock == -1 || !options.control_persist |
| || options.control_persist_timeout == 0) { |
| /* not using a ControlPersist timeout */ |
| control_persist_exit_time = 0; |
| } else if (channel_still_open(ssh)) { |
| /* some client connections are still open */ |
| if (control_persist_exit_time > 0) |
| debug2("%s: cancel scheduled exit", __func__); |
| control_persist_exit_time = 0; |
| } else if (control_persist_exit_time <= 0) { |
| /* a client connection has recently closed */ |
| control_persist_exit_time = monotime() + |
| (time_t)options.control_persist_timeout; |
| debug2("%s: schedule exit in %d seconds", __func__, |
| options.control_persist_timeout); |
| } |
| /* else we are already counting down to the timeout */ |
| } |
| |
| #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_" |
| static int |
| client_x11_display_valid(const char *display) |
| { |
| size_t i, dlen; |
| |
| if (display == NULL) |
| return 0; |
| |
| dlen = strlen(display); |
| for (i = 0; i < dlen; i++) { |
| if (!isalnum((u_char)display[i]) && |
| strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) { |
| debug("Invalid character '%c' in DISPLAY", display[i]); |
| return 0; |
| } |
| } |
| return 1; |
| } |
| |
| #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" |
| #define X11_TIMEOUT_SLACK 60 |
| int |
| client_x11_get_proto(struct ssh *ssh, const char *display, |
| const char *xauth_path, u_int trusted, u_int timeout, |
| char **_proto, char **_data) |
| { |
| char *cmd, line[512], xdisplay[512]; |
| char xauthfile[PATH_MAX], xauthdir[PATH_MAX]; |
| static char proto[512], data[512]; |
| FILE *f; |
| int got_data = 0, generated = 0, do_unlink = 0, r; |
| struct stat st; |
| u_int now, x11_timeout_real; |
| |
| *_proto = proto; |
| *_data = data; |
| proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0'; |
| |
| if (!client_x11_display_valid(display)) { |
| if (display != NULL) |
| logit("DISPLAY \"%s\" invalid; disabling X11 forwarding", |
| display); |
| return -1; |
| } |
| if (xauth_path != NULL && stat(xauth_path, &st) == -1) { |
| debug("No xauth program."); |
| xauth_path = NULL; |
| } |
| |
| if (xauth_path != NULL) { |
| /* |
| * Handle FamilyLocal case where $DISPLAY does |
| * not match an authorization entry. For this we |
| * just try "xauth list unix:displaynum.screennum". |
| * XXX: "localhost" match to determine FamilyLocal |
| * is not perfect. |
| */ |
| if (strncmp(display, "localhost:", 10) == 0) { |
| if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s", |
| display + 10)) < 0 || |
| (size_t)r >= sizeof(xdisplay)) { |
| error("%s: display name too long", __func__); |
| return -1; |
| } |
| display = xdisplay; |
| } |
| if (trusted == 0) { |
| /* |
| * Generate an untrusted X11 auth cookie. |
| * |
| * The authentication cookie should briefly outlive |
| * ssh's willingness to forward X11 connections to |
| * avoid nasty fail-open behaviour in the X server. |
| */ |
| mktemp_proto(xauthdir, sizeof(xauthdir)); |
| if (mkdtemp(xauthdir) == NULL) { |
| error("%s: mkdtemp: %s", |
| __func__, strerror(errno)); |
| return -1; |
| } |
| do_unlink = 1; |
| if ((r = snprintf(xauthfile, sizeof(xauthfile), |
| "%s/xauthfile", xauthdir)) < 0 || |
| (size_t)r >= sizeof(xauthfile)) { |
| error("%s: xauthfile path too long", __func__); |
| rmdir(xauthdir); |
| return -1; |
| } |
| |
| if (timeout == 0) { |
| /* auth doesn't time out */ |
| xasprintf(&cmd, "%s -f %s generate %s %s " |
| "untrusted 2>%s", |
| xauth_path, xauthfile, display, |
| SSH_X11_PROTO, _PATH_DEVNULL); |
| } else { |
| /* Add some slack to requested expiry */ |
| if (timeout < UINT_MAX - X11_TIMEOUT_SLACK) |
| x11_timeout_real = timeout + |
| X11_TIMEOUT_SLACK; |
| else { |
| /* Don't overflow on long timeouts */ |
| x11_timeout_real = UINT_MAX; |
| } |
| xasprintf(&cmd, "%s -f %s generate %s %s " |
| "untrusted timeout %u 2>%s", |
| xauth_path, xauthfile, display, |
| SSH_X11_PROTO, x11_timeout_real, |
| _PATH_DEVNULL); |
| } |
| debug2("%s: xauth command: %s", __func__, cmd); |
| |
| if (timeout != 0 && x11_refuse_time == 0) { |
| now = monotime() + 1; |
| if (UINT_MAX - timeout < now) |
| x11_refuse_time = UINT_MAX; |
| else |
| x11_refuse_time = now + timeout; |
| channel_set_x11_refuse_time(ssh, |
| x11_refuse_time); |
| } |
| if (system(cmd) == 0) |
| generated = 1; |
| free(cmd); |
| } |
| |
| /* |
| * When in untrusted mode, we read the cookie only if it was |
| * successfully generated as an untrusted one in the step |
| * above. |
| */ |
| if (trusted || generated) { |
| xasprintf(&cmd, |
| "%s %s%s list %s 2>" _PATH_DEVNULL, |
| xauth_path, |
| generated ? "-f " : "" , |
| generated ? xauthfile : "", |
| display); |
| debug2("x11_get_proto: %s", cmd); |
| f = popen(cmd, "r"); |
| if (f && fgets(line, sizeof(line), f) && |
| sscanf(line, "%*s %511s %511s", proto, data) == 2) |
| got_data = 1; |
| if (f) |
| pclose(f); |
| free(cmd); |
| } |
| } |
| |
| if (do_unlink) { |
| unlink(xauthfile); |
| rmdir(xauthdir); |
| } |
| |
| /* Don't fall back to fake X11 data for untrusted forwarding */ |
| if (!trusted && !got_data) { |
| error("Warning: untrusted X11 forwarding setup failed: " |
| "xauth key data not generated"); |
| return -1; |
| } |
| |
| /* |
| * If we didn't get authentication data, just make up some |
| * data. The forwarding code will check the validity of the |
| * response anyway, and substitute this data. The X11 |
| * server, however, will ignore this fake data and use |
| * whatever authentication mechanisms it was using otherwise |
| * for the local connection. |
| */ |
| if (!got_data) { |
| u_int8_t rnd[16]; |
| u_int i; |
| |
| logit("Warning: No xauth data; " |
| "using fake authentication data for X11 forwarding."); |
| strlcpy(proto, SSH_X11_PROTO, sizeof proto); |
| arc4random_buf(rnd, sizeof(rnd)); |
| for (i = 0; i < sizeof(rnd); i++) { |
| snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", |
| rnd[i]); |
| } |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * 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(struct ssh *ssh) |
| { |
| if (!received_window_change_signal) |
| return; |
| received_window_change_signal = 0; |
| debug2("%s: changed", __func__); |
| channel_send_window_changes(ssh); |
| } |
| |
| static int |
| client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| struct global_confirm *gc; |
| |
| if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) |
| return 0; |
| if (gc->cb != NULL) |
| gc->cb(ssh, type, seq, gc->ctx); |
| if (--gc->ref_count <= 0) { |
| TAILQ_REMOVE(&global_confirms, gc, entry); |
| explicit_bzero(gc, sizeof(*gc)); |
| free(gc); |
| } |
| |
| ssh_packet_set_alive_timeouts(ssh, 0); |
| return 0; |
| } |
| |
| static void |
| server_alive_check(struct ssh *ssh) |
| { |
| int r; |
| |
| if (ssh_packet_inc_alive_timeouts(ssh) > options.server_alive_count_max) { |
| logit("Timeout, server %s not responding.", host); |
| cleanup_exit(255); |
| } |
| if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || |
| (r = sshpkt_put_cstring(ssh, "keepalive@openssh.com")) != 0 || |
| (r = sshpkt_put_u8(ssh, 1)) != 0 || /* boolean: want reply */ |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: send packet: %s", __func__, ssh_err(r)); |
| /* Insert an empty placeholder to maintain ordering */ |
| client_register_global_confirm(NULL, NULL); |
| } |
| |
| /* |
| * 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(struct ssh *ssh, |
| fd_set **readsetp, fd_set **writesetp, |
| int *maxfdp, u_int *nallocp, int rekeying) |
| { |
| struct timeval tv, *tvp; |
| int timeout_secs; |
| time_t minwait_secs = 0, server_alive_time = 0, now = monotime(); |
| int r, ret; |
| |
| /* Add any selections by the channel mechanism. */ |
| channel_prepare_select(ssh, readsetp, writesetp, maxfdp, |
| nallocp, &minwait_secs); |
| |
| /* channel_prepare_select could have closed the last channel */ |
| if (session_closed && !channel_still_open(ssh) && |
| !ssh_packet_have_data_to_write(ssh)) { |
| /* clear mask since we did not call select() */ |
| memset(*readsetp, 0, *nallocp); |
| memset(*writesetp, 0, *nallocp); |
| return; |
| } |
| |
| FD_SET(connection_in, *readsetp); |
| |
| /* Select server connection if have data to write to the server. */ |
| if (ssh_packet_have_data_to_write(ssh)) |
| 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, or a timeout expires. |
| */ |
| |
| timeout_secs = INT_MAX; /* we use INT_MAX to mean no timeout */ |
| if (options.server_alive_interval > 0) { |
| timeout_secs = options.server_alive_interval; |
| server_alive_time = now + options.server_alive_interval; |
| } |
| if (options.rekey_interval > 0 && !rekeying) |
| timeout_secs = MINIMUM(timeout_secs, |
| ssh_packet_get_rekey_timeout(ssh)); |
| set_control_persist_exit_time(ssh); |
| if (control_persist_exit_time > 0) { |
| timeout_secs = MINIMUM(timeout_secs, |
| control_persist_exit_time - now); |
| if (timeout_secs < 0) |
| timeout_secs = 0; |
| } |
| if (minwait_secs != 0) |
| timeout_secs = MINIMUM(timeout_secs, (int)minwait_secs); |
| if (timeout_secs == INT_MAX) |
| tvp = NULL; |
| else { |
| tv.tv_sec = timeout_secs; |
| tv.tv_usec = 0; |
| tvp = &tv; |
| } |
| |
| ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); |
| if (ret == -1) { |
| /* |
| * 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. */ |
| if ((r = sshbuf_putf(stderr_buffer, |
| "select: %s\r\n", strerror(errno))) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| quit_pending = 1; |
| } else if (ret == 0) { |
| /* |
| * Timeout. Could have been either keepalive or rekeying. |
| * Keepalive we check here, rekeying is checked in clientloop. |
| */ |
| if (server_alive_time != 0 && server_alive_time <= monotime()) |
| server_alive_check(ssh); |
| } |
| |
| } |
| |
| static void |
| client_suspend_self(struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr) |
| { |
| /* Flush stdout and stderr buffers. */ |
| if (sshbuf_len(bout) > 0) |
| atomicio(vwrite, fileno(stdout), sshbuf_mutable_ptr(bout), |
| sshbuf_len(bout)); |
| if (sshbuf_len(berr) > 0) |
| atomicio(vwrite, fileno(stderr), sshbuf_mutable_ptr(berr), |
| sshbuf_len(berr)); |
| |
| leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); |
| |
| sshbuf_reset(bin); |
| sshbuf_reset(bout); |
| sshbuf_reset(berr); |
| |
| /* Send the suspend signal to the program itself. */ |
| kill(getpid(), SIGTSTP); |
| |
| /* Reset window sizes in case they have changed */ |
| received_window_change_signal = 1; |
| |
| enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); |
| } |
| |
| static void |
| client_process_net_input(struct ssh *ssh, fd_set *readset) |
| { |
| char buf[SSH_IOBUFSZ]; |
| int r, len; |
| |
| /* |
| * 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. |
| */ |
| if ((r = sshbuf_putf(stderr_buffer, |
| "Connection to %.300s closed by remote host.\r\n", |
| host)) != 0) |
| fatal("%s: buffer error: %s", |
| __func__, ssh_err(r)); |
| 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 == -1 && |
| (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK)) |
| len = 0; |
| |
| if (len == -1) { |
| /* |
| * An error has encountered. Perhaps there is a |
| * network problem. |
| */ |
| if ((r = sshbuf_putf(stderr_buffer, |
| "Read from remote host %.300s: %.100s\r\n", |
| host, strerror(errno))) != 0) |
| fatal("%s: buffer error: %s", |
| __func__, ssh_err(r)); |
| quit_pending = 1; |
| return; |
| } |
| ssh_packet_process_incoming(ssh, buf, len); |
| } |
| } |
| |
| static void |
| client_status_confirm(struct ssh *ssh, int type, Channel *c, void *ctx) |
| { |
| struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; |
| char errmsg[256]; |
| int r, tochan; |
| |
| /* |
| * If a TTY was explicitly requested, then a failure to allocate |
| * one is fatal. |
| */ |
| if (cr->action == CONFIRM_TTY && |
| (options.request_tty == REQUEST_TTY_FORCE || |
| options.request_tty == REQUEST_TTY_YES)) |
| cr->action = CONFIRM_CLOSE; |
| |
| /* XXX suppress on mux _client_ quietmode */ |
| tochan = options.log_level >= SYSLOG_LEVEL_ERROR && |
| c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; |
| |
| if (type == SSH2_MSG_CHANNEL_SUCCESS) { |
| debug2("%s request accepted on channel %d", |
| cr->request_type, c->self); |
| } else if (type == SSH2_MSG_CHANNEL_FAILURE) { |
| if (tochan) { |
| snprintf(errmsg, sizeof(errmsg), |
| "%s request failed\r\n", cr->request_type); |
| } else { |
| snprintf(errmsg, sizeof(errmsg), |
| "%s request failed on channel %d", |
| cr->request_type, c->self); |
| } |
| /* If error occurred on primary session channel, then exit */ |
| if (cr->action == CONFIRM_CLOSE && c->self == session_ident) |
| fatal("%s", errmsg); |
| /* |
| * If error occurred on mux client, append to |
| * their stderr. |
| */ |
| if (tochan) { |
| if ((r = sshbuf_put(c->extended, errmsg, |
| strlen(errmsg))) != 0) |
| fatal("%s: buffer error %s", __func__, |
| ssh_err(r)); |
| } else |
| error("%s", errmsg); |
| if (cr->action == CONFIRM_TTY) { |
| /* |
| * If a TTY allocation error occurred, then arrange |
| * for the correct TTY to leave raw mode. |
| */ |
| if (c->self == session_ident) |
| leave_raw_mode(0); |
| else |
| mux_tty_alloc_failed(ssh, c); |
| } else if (cr->action == CONFIRM_CLOSE) { |
| chan_read_failed(ssh, c); |
| chan_write_failed(ssh, c); |
| } |
| } |
| free(cr); |
| } |
| |
| static void |
| client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx) |
| { |
| free(ctx); |
| } |
| |
| void |
| client_expect_confirm(struct ssh *ssh, int id, const char *request, |
| enum confirm_action action) |
| { |
| struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr)); |
| |
| cr->request_type = request; |
| cr->action = action; |
| |
| channel_register_status_confirm(ssh, id, client_status_confirm, |
| client_abandon_status_confirm, cr); |
| } |
| |
| void |
| client_register_global_confirm(global_confirm_cb *cb, void *ctx) |
| { |
| struct global_confirm *gc, *last_gc; |
| |
| /* Coalesce identical callbacks */ |
| last_gc = TAILQ_LAST(&global_confirms, global_confirms); |
| if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { |
| if (++last_gc->ref_count >= INT_MAX) |
| fatal("%s: last_gc->ref_count = %d", |
| __func__, last_gc->ref_count); |
| return; |
| } |
| |
| gc = xcalloc(1, sizeof(*gc)); |
| gc->cb = cb; |
| gc->ctx = ctx; |
| gc->ref_count = 1; |
| TAILQ_INSERT_TAIL(&global_confirms, gc, entry); |
| } |
| |
| static void |
| process_cmdline(struct ssh *ssh) |
| { |
| void (*handler)(int); |
| char *s, *cmd; |
| int ok, delete = 0, local = 0, remote = 0, dynamic = 0; |
| struct Forward fwd; |
| |
| memset(&fwd, 0, sizeof(fwd)); |
| |
| leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); |
| handler = ssh_signal(SIGINT, SIG_IGN); |
| cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); |
| if (s == NULL) |
| goto out; |
| while (isspace((u_char)*s)) |
| s++; |
| if (*s == '-') |
| s++; /* Skip cmdline '-', if any */ |
| if (*s == '\0') |
| goto out; |
| |
| if (*s == 'h' || *s == 'H' || *s == '?') { |
| logit("Commands:"); |
| logit(" -L[bind_address:]port:host:hostport " |
| "Request local forward"); |
| logit(" -R[bind_address:]port:host:hostport " |
| "Request remote forward"); |
| logit(" -D[bind_address:]port " |
| "Request dynamic forward"); |
| logit(" -KL[bind_address:]port " |
| "Cancel local forward"); |
| logit(" -KR[bind_address:]port " |
| "Cancel remote forward"); |
| logit(" -KD[bind_address:]port " |
| "Cancel dynamic forward"); |
| if (!options.permit_local_command) |
| goto out; |
| logit(" !args " |
| "Execute local command"); |
| goto out; |
| } |
| |
| if (*s == '!' && options.permit_local_command) { |
| s++; |
| ssh_local_cmd(s); |
| goto out; |
| } |
| |
| if (*s == 'K') { |
| delete = 1; |
| s++; |
| } |
| if (*s == 'L') |
| local = 1; |
| else if (*s == 'R') |
| remote = 1; |
| else if (*s == 'D') |
| dynamic = 1; |
| else { |
| logit("Invalid command."); |
| goto out; |
| } |
| |
| while (isspace((u_char)*++s)) |
| ; |
| |
| /* XXX update list of forwards in options */ |
| if (delete) { |
| /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */ |
| if (!parse_forward(&fwd, s, 1, 0)) { |
| logit("Bad forwarding close specification."); |
| goto out; |
| } |
| if (remote) |
| ok = channel_request_rforward_cancel(ssh, &fwd) == 0; |
| else if (dynamic) |
| ok = channel_cancel_lport_listener(ssh, &fwd, |
| 0, &options.fwd_opts) > 0; |
| else |
| ok = channel_cancel_lport_listener(ssh, &fwd, |
| CHANNEL_CANCEL_PORT_STATIC, |
| &options.fwd_opts) > 0; |
| if (!ok) { |
| logit("Unknown port forwarding."); |
| goto out; |
| } |
| logit("Canceled forwarding."); |
| } else { |
| if (!parse_forward(&fwd, s, dynamic, remote)) { |
| logit("Bad forwarding specification."); |
| goto out; |
| } |
| if (local || dynamic) { |
| if (!channel_setup_local_fwd_listener(ssh, &fwd, |
| &options.fwd_opts)) { |
| logit("Port forwarding failed."); |
| goto out; |
| } |
| } else { |
| if (channel_request_remote_forwarding(ssh, &fwd) < 0) { |
| logit("Port forwarding failed."); |
| goto out; |
| } |
| } |
| logit("Forwarding port."); |
| } |
| |
| out: |
| ssh_signal(SIGINT, handler); |
| enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); |
| free(cmd); |
| free(fwd.listen_host); |
| free(fwd.listen_path); |
| free(fwd.connect_host); |
| free(fwd.connect_path); |
| } |
| |
| /* reasons to suppress output of an escape command in help output */ |
| #define SUPPRESS_NEVER 0 /* never suppress, always show */ |
| #define SUPPRESS_MUXCLIENT 1 /* don't show in mux client sessions */ |
| #define SUPPRESS_MUXMASTER 2 /* don't show in mux master sessions */ |
| #define SUPPRESS_SYSLOG 4 /* don't show when logging to syslog */ |
| struct escape_help_text { |
| const char *cmd; |
| const char *text; |
| unsigned int flags; |
| }; |
| static struct escape_help_text esc_txt[] = { |
| {".", "terminate session", SUPPRESS_MUXMASTER}, |
| {".", "terminate connection (and any multiplexed sessions)", |
| SUPPRESS_MUXCLIENT}, |
| {"B", "send a BREAK to the remote system", SUPPRESS_NEVER}, |
| {"C", "open a command line", SUPPRESS_MUXCLIENT}, |
| {"R", "request rekey", SUPPRESS_NEVER}, |
| {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT}, |
| {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT}, |
| {"#", "list forwarded connections", SUPPRESS_NEVER}, |
| {"&", "background ssh (when waiting for connections to terminate)", |
| SUPPRESS_MUXCLIENT}, |
| {"?", "this message", SUPPRESS_NEVER}, |
| }; |
| |
| static void |
| print_escape_help(struct sshbuf *b, int escape_char, int mux_client, |
| int using_stderr) |
| { |
| unsigned int i, suppress_flags; |
| int r; |
| |
| if ((r = sshbuf_putf(b, |
| "%c?\r\nSupported escape sequences:\r\n", escape_char)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| |
| suppress_flags = |
| (mux_client ? SUPPRESS_MUXCLIENT : 0) | |
| (mux_client ? 0 : SUPPRESS_MUXMASTER) | |
| (using_stderr ? 0 : SUPPRESS_SYSLOG); |
| |
| for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) { |
| if (esc_txt[i].flags & suppress_flags) |
| continue; |
| if ((r = sshbuf_putf(b, " %c%-3s - %s\r\n", |
| escape_char, esc_txt[i].cmd, esc_txt[i].text)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| } |
| |
| if ((r = sshbuf_putf(b, |
| " %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)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| } |
| |
| /* |
| * Process the characters one by one. |
| */ |
| static int |
| process_escapes(struct ssh *ssh, Channel *c, |
| struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr, |
| char *buf, int len) |
| { |
| pid_t pid; |
| int r, bytes = 0; |
| u_int i; |
| u_char ch; |
| char *s; |
| struct escape_filter_ctx *efc = c->filter_ctx == NULL ? |
| NULL : (struct escape_filter_ctx *)c->filter_ctx; |
| |
| if (c->filter_ctx == NULL) |
| return 0; |
| |
| if (len <= 0) |
| return (0); |
| |
| for (i = 0; i < (u_int)len; i++) { |
| /* Get one character at a time. */ |
| ch = buf[i]; |
| |
| if (efc->escape_pending) { |
| /* We have previously seen an escape character. */ |
| /* Clear the flag now. */ |
| efc->escape_pending = 0; |
| |
| /* Process the escaped character. */ |
| switch (ch) { |
| case '.': |
| /* Terminate the connection. */ |
| if ((r = sshbuf_putf(berr, "%c.\r\n", |
| efc->escape_char)) != 0) |
| fatal("%s: buffer error: %s", |
| __func__, ssh_err(r)); |
| if (c && c->ctl_chan != -1) { |
| chan_read_failed(ssh, c); |
| chan_write_failed(ssh, c); |
| if (c->detach_user) { |
| c->detach_user(ssh, |
| c->self, NULL); |
| } |
| c->type = SSH_CHANNEL_ABANDONED; |
| sshbuf_reset(c->input); |
| chan_ibuf_empty(ssh, c); |
| return 0; |
| } else |
| quit_pending = 1; |
| return -1; |
| |
| case 'Z' - 64: |
| /* XXX support this for mux clients */ |
| if (c && c->ctl_chan != -1) { |
| char b[16]; |
| noescape: |
| if (ch == 'Z' - 64) |
| snprintf(b, sizeof b, "^Z"); |
| else |
| snprintf(b, sizeof b, "%c", ch); |
| if ((r = sshbuf_putf(berr, |
| "%c%s escape not available to " |
| "multiplexed sessions\r\n", |
| efc->escape_char, b)) != 0) |
| fatal("%s: buffer error: %s", |
| __func__, ssh_err(r)); |
| continue; |
| } |
| /* Suspend the program. Inform the user */ |
| if ((r = sshbuf_putf(berr, |
| "%c^Z [suspend ssh]\r\n", |
| efc->escape_char)) != 0) |
| fatal("%s: buffer error: %s", |
| __func__, ssh_err(r)); |
| |
| /* Restore terminal modes and suspend. */ |
| client_suspend_self(bin, bout, berr); |
| |
| /* We have been continued. */ |
| continue; |
| |
| case 'B': |
| if ((r = sshbuf_putf(berr, |
| "%cB\r\n", efc->escape_char)) != 0) |
| fatal("%s: buffer error: %s", |
| __func__, ssh_err(r)); |
| channel_request_start(ssh, c->self, "break", 0); |
| if ((r = sshpkt_put_u32(ssh, 1000)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: send packet: %s", __func__, |
| ssh_err(r)); |
| continue; |
| |
| case 'R': |
| if (datafellows & SSH_BUG_NOREKEY) |
| logit("Server does not " |
| "support re-keying"); |
| else |
| need_rekeying = 1; |
| continue; |
| |
| case 'V': |
| /* FALLTHROUGH */ |
| case 'v': |
| if (c && c->ctl_chan != -1) |
| goto noescape; |
| if (!log_is_on_stderr()) { |
| if ((r = sshbuf_putf(berr, |
| "%c%c [Logging to syslog]\r\n", |
| efc->escape_char, ch)) != 0) |
| fatal("%s: buffer error: %s", |
| __func__, ssh_err(r)); |
| continue; |
| } |
| if (ch == 'V' && options.log_level > |
| SYSLOG_LEVEL_QUIET) |
| log_change_level(--options.log_level); |
| if (ch == 'v' && options.log_level < |
| SYSLOG_LEVEL_DEBUG3) |
| log_change_level(++options.log_level); |
| if ((r = sshbuf_putf(berr, |
| "%c%c [LogLevel %s]\r\n", |
| efc->escape_char, ch, |
| log_level_name(options.log_level))) != 0) |
| fatal("%s: buffer error: %s", |
| __func__, ssh_err(r)); |
| continue; |
| |
| case '&': |
| if (c && c->ctl_chan != -1) |
| goto noescape; |
| /* |
| * Detach the program (continue to serve |
| * connections, but put in background and no |
| * more new connections). |
| */ |
| /* Restore tty modes. */ |
| leave_raw_mode( |
| options.request_tty == REQUEST_TTY_FORCE); |
| |
| /* Stop listening for new connections. */ |
| channel_stop_listening(ssh); |
| |
| if ((r = sshbuf_putf(berr, |
| "%c& [backgrounded]\n", efc->escape_char)) |
| != 0) |
| fatal("%s: buffer error: %s", |
| __func__, ssh_err(r)); |
| |
| /* Fork into background. */ |
| pid = fork(); |
| if (pid == -1) { |
| error("fork: %.100s", strerror(errno)); |
| continue; |
| } |
| if (pid != 0) { /* This is the parent. */ |
| /* The parent just exits. */ |
| exit(0); |
| } |
| /* The child continues serving connections. */ |
| /* fake EOF on stdin */ |
| if ((r = sshbuf_put_u8(bin, 4)) != 0) |
| fatal("%s: buffer error: %s", |
| __func__, ssh_err(r)); |
| return -1; |
| case '?': |
| print_escape_help(berr, efc->escape_char, |
| (c && c->ctl_chan != -1), |
| log_is_on_stderr()); |
| continue; |
| |
| case '#': |
| if ((r = sshbuf_putf(berr, "%c#\r\n", |
| efc->escape_char)) != 0) |
| fatal("%s: buffer error: %s", |
| __func__, ssh_err(r)); |
| s = channel_open_message(ssh); |
| if ((r = sshbuf_put(berr, s, strlen(s))) != 0) |
| fatal("%s: buffer error: %s", |
| __func__, ssh_err(r)); |
| free(s); |
| continue; |
| |
| case 'C': |
| if (c && c->ctl_chan != -1) |
| goto noescape; |
| process_cmdline(ssh); |
| continue; |
| |
| default: |
| if (ch != efc->escape_char) { |
| if ((r = sshbuf_put_u8(bin, |
| efc->escape_char)) != 0) |
| fatal("%s: buffer error: %s", |
| __func__, ssh_err(r)); |
| 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 == efc->escape_char) { |
| /* |
| * It is. Set the flag and continue to |
| * next character. |
| */ |
| efc->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'); |
| if ((r = sshbuf_put_u8(bin, ch)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| bytes++; |
| } |
| return bytes; |
| } |
| |
| /* |
| * 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(struct ssh *ssh) |
| { |
| ssh_dispatch_run_fatal(ssh, DISPATCH_NONBLOCK, &quit_pending); |
| } |
| |
| /* scan buf[] for '~' before sending data to the peer */ |
| |
| /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ |
| void * |
| client_new_escape_filter_ctx(int escape_char) |
| { |
| struct escape_filter_ctx *ret; |
| |
| ret = xcalloc(1, sizeof(*ret)); |
| ret->escape_pending = 0; |
| ret->escape_char = escape_char; |
| return (void *)ret; |
| } |
| |
| /* Free the escape filter context on channel free */ |
| void |
| client_filter_cleanup(struct ssh *ssh, int cid, void *ctx) |
| { |
| free(ctx); |
| } |
| |
| int |
| client_simple_escape_filter(struct ssh *ssh, Channel *c, char *buf, int len) |
| { |
| if (c->extended_usage != CHAN_EXTENDED_WRITE) |
| return 0; |
| |
| return process_escapes(ssh, c, c->input, c->output, c->extended, |
| buf, len); |
| } |
| |
| static void |
| client_channel_closed(struct ssh *ssh, int id, void *arg) |
| { |
| channel_cancel_cleanup(ssh, id); |
| session_closed = 1; |
| leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); |
| } |
| |
| /* |
| * 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(struct ssh *ssh, int have_pty, int escape_char_arg, |
| int ssh2_chan_id) |
| { |
| fd_set *readset = NULL, *writeset = NULL; |
| double start_time, total_time; |
| int r, max_fd = 0, max_fd2 = 0, len; |
| u_int64_t ibytes, obytes; |
| u_int nalloc = 0; |
| char buf[100]; |
| |
| debug("Entering interactive session."); |
| |
| if (options.control_master && |
| !option_clear_or_none(options.control_path)) { |
| debug("pledge: id"); |
| if (pledge("stdio rpath wpath cpath unix inet dns recvfd sendfd proc exec id tty", |
| NULL) == -1) |
| fatal("%s pledge(): %s", __func__, strerror(errno)); |
| |
| } else if (options.forward_x11 || options.permit_local_command) { |
| debug("pledge: exec"); |
| if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty", |
| NULL) == -1) |
| fatal("%s pledge(): %s", __func__, strerror(errno)); |
| |
| } else if (options.update_hostkeys) { |
| debug("pledge: filesystem full"); |
| if (pledge("stdio rpath wpath cpath unix inet dns proc tty", |
| NULL) == -1) |
| fatal("%s pledge(): %s", __func__, strerror(errno)); |
| |
| } else if (!option_clear_or_none(options.proxy_command) || |
| fork_after_authentication_flag) { |
| debug("pledge: proc"); |
| if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1) |
| fatal("%s pledge(): %s", __func__, strerror(errno)); |
| |
| } else { |
| debug("pledge: network"); |
| if (pledge("stdio unix inet dns proc tty", NULL) == -1) |
| fatal("%s pledge(): %s", __func__, strerror(errno)); |
| } |
| |
| start_time = monotime_double(); |
| |
| /* Initialize variables. */ |
| last_was_cr = 1; |
| exit_status = -1; |
| connection_in = ssh_packet_get_connection_in(ssh); |
| connection_out = ssh_packet_get_connection_out(ssh); |
| max_fd = MAXIMUM(connection_in, connection_out); |
| |
| quit_pending = 0; |
| |
| /* Initialize buffer. */ |
| if ((stderr_buffer = sshbuf_new()) == NULL) |
| fatal("%s: sshbuf_new failed", __func__); |
| |
| client_init_dispatch(ssh); |
| |
| /* |
| * Set signal handlers, (e.g. to restore non-blocking mode) |
| * but don't overwrite SIG_IGN, matches behaviour from rsh(1) |
| */ |
| if (ssh_signal(SIGHUP, SIG_IGN) != SIG_IGN) |
| ssh_signal(SIGHUP, signal_handler); |
| if (ssh_signal(SIGINT, SIG_IGN) != SIG_IGN) |
| ssh_signal(SIGINT, signal_handler); |
| if (ssh_signal(SIGQUIT, SIG_IGN) != SIG_IGN) |
| ssh_signal(SIGQUIT, signal_handler); |
| if (ssh_signal(SIGTERM, SIG_IGN) != SIG_IGN) |
| ssh_signal(SIGTERM, signal_handler); |
| ssh_signal(SIGWINCH, window_change_handler); |
| |
| if (have_pty) |
| enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); |
| |
| session_ident = ssh2_chan_id; |
| if (session_ident != -1) { |
| if (escape_char_arg != SSH_ESCAPECHAR_NONE) { |
| channel_register_filter(ssh, session_ident, |
| client_simple_escape_filter, NULL, |
| client_filter_cleanup, |
| client_new_escape_filter_ctx( |
| escape_char_arg)); |
| } |
| channel_register_cleanup(ssh, session_ident, |
| client_channel_closed, 0); |
| } |
| |
| /* 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(ssh); |
| |
| if (session_closed && !channel_still_open(ssh)) |
| break; |
| |
| if (ssh_packet_is_rekeying(ssh)) { |
| debug("rekeying in progress"); |
| } else if (need_rekeying) { |
| /* manual rekey request */ |
| debug("need rekeying"); |
| if ((r = kex_start_rekex(ssh)) != 0) |
| fatal("%s: kex_start_rekex: %s", __func__, |
| ssh_err(r)); |
| need_rekeying = 0; |
| } else { |
| /* |
| * Make packets from buffered channel data, and |
| * enqueue them for sending to the server. |
| */ |
| if (ssh_packet_not_very_much_data_to_write(ssh)) |
| channel_output_poll(ssh); |
| |
| /* |
| * Check if the window size has changed, and buffer a |
| * message about it to the server if so. |
| */ |
| client_check_window_change(ssh); |
| |
| 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(ssh, &readset, &writeset, |
| &max_fd2, &nalloc, ssh_packet_is_rekeying(ssh)); |
| |
| if (quit_pending) |
| break; |
| |
| /* Do channel operations unless rekeying in progress. */ |
| if (!ssh_packet_is_rekeying(ssh)) |
| channel_after_select(ssh, readset, writeset); |
| |
| /* Buffer input from the connection. */ |
| client_process_net_input(ssh, readset); |
| |
| if (quit_pending) |
| break; |
| |
| /* |
| * Send as much buffered packet data as possible to the |
| * sender. |
| */ |
| if (FD_ISSET(connection_out, writeset)) { |
| if ((r = ssh_packet_write_poll(ssh)) != 0) { |
| sshpkt_fatal(ssh, r, |
| "%s: ssh_packet_write_poll", __func__); |
| } |
| } |
| |
| /* |
| * If we are a backgrounded control master, and the |
| * timeout has expired without any active client |
| * connections, then quit. |
| */ |
| if (control_persist_exit_time > 0) { |
| if (monotime() >= control_persist_exit_time) { |
| debug("ControlPersist timeout expired"); |
| break; |
| } |
| } |
| } |
| free(readset); |
| free(writeset); |
| |
| /* Terminate the session. */ |
| |
| /* Stop watching for window change. */ |
| ssh_signal(SIGWINCH, SIG_DFL); |
| |
| if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || |
| (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_BY_APPLICATION)) != 0 || |
| (r = sshpkt_put_cstring(ssh, "disconnected by user")) != 0 || |
| (r = sshpkt_put_cstring(ssh, "")) != 0 || /* language tag */ |
| (r = sshpkt_send(ssh)) != 0 || |
| (r = ssh_packet_write_wait(ssh)) != 0) |
| fatal("%s: send disconnect: %s", __func__, ssh_err(r)); |
| |
| channel_free_all(ssh); |
| |
| if (have_pty) |
| leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); |
| |
| /* 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 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) { |
| verbose("Killed by signal %d.", (int) received_signal); |
| cleanup_exit(0); |
| } |
| |
| /* |
| * 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) { |
| if ((r = sshbuf_putf(stderr_buffer, |
| "Connection to %.64s closed.\r\n", host)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| } |
| |
| /* Output any buffered data for stderr. */ |
| if (sshbuf_len(stderr_buffer) > 0) { |
| len = atomicio(vwrite, fileno(stderr), |
| (u_char *)sshbuf_ptr(stderr_buffer), |
| sshbuf_len(stderr_buffer)); |
| if (len < 0 || (u_int)len != sshbuf_len(stderr_buffer)) |
| error("Write failed flushing stderr buffer."); |
| else if ((r = sshbuf_consume(stderr_buffer, len)) != 0) |
| fatal("%s: buffer error: %s", __func__, ssh_err(r)); |
| } |
| |
| /* Clear and free any buffers. */ |
| explicit_bzero(buf, sizeof(buf)); |
| sshbuf_free(stderr_buffer); |
| |
| /* Report bytes transferred, and transfer rates. */ |
| total_time = monotime_double() - start_time; |
| ssh_packet_get_bytes(ssh, &ibytes, &obytes); |
| verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", |
| (unsigned long long)obytes, (unsigned long long)ibytes, total_time); |
| if (total_time > 0) |
| verbose("Bytes per second: sent %.1f, received %.1f", |
| obytes / total_time, ibytes / total_time); |
| /* Return the exit status of the program. */ |
| debug("Exit status %d", exit_status); |
| return exit_status; |
| } |
| |
| /*********/ |
| |
| static Channel * |
| client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type, |
| int rchan, u_int rwindow, u_int rmaxpack) |
| { |
| Channel *c = NULL; |
| struct sshbuf *b = NULL; |
| char *listen_address, *originator_address; |
| u_int listen_port, originator_port; |
| int r; |
| |
| /* Get rest of the packet */ |
| if ((r = sshpkt_get_cstring(ssh, &listen_address, NULL)) != 0 || |
| (r = sshpkt_get_u32(ssh, &listen_port)) != 0 || |
| (r = sshpkt_get_cstring(ssh, &originator_address, NULL)) != 0 || |
| (r = sshpkt_get_u32(ssh, &originator_port)) != 0 || |
| (r = sshpkt_get_end(ssh)) != 0) |
| fatal("%s: parse packet: %s", __func__, ssh_err(r)); |
| |
| debug("%s: listen %s port %d, originator %s port %d", __func__, |
| listen_address, listen_port, originator_address, originator_port); |
| |
| if (listen_port > 0xffff) |
| error("%s: invalid listen port", __func__); |
| else if (originator_port > 0xffff) |
| error("%s: invalid originator port", __func__); |
| else { |
| c = channel_connect_by_listen_address(ssh, |
| listen_address, listen_port, "forwarded-tcpip", |
| originator_address); |
| } |
| |
| if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { |
| if ((b = sshbuf_new()) == NULL) { |
| error("%s: alloc reply", __func__); |
| goto out; |
| } |
| /* reconstruct and send to muxclient */ |
| if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ |
| (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 || |
| (r = sshbuf_put_cstring(b, request_type)) != 0 || |
| (r = sshbuf_put_u32(b, rchan)) != 0 || |
| (r = sshbuf_put_u32(b, rwindow)) != 0 || |
| (r = sshbuf_put_u32(b, rmaxpack)) != 0 || |
| (r = sshbuf_put_cstring(b, listen_address)) != 0 || |
| (r = sshbuf_put_u32(b, listen_port)) != 0 || |
| (r = sshbuf_put_cstring(b, originator_address)) != 0 || |
| (r = sshbuf_put_u32(b, originator_port)) != 0 || |
| (r = sshbuf_put_stringb(c->output, b)) != 0) { |
| error("%s: compose for muxclient %s", __func__, |
| ssh_err(r)); |
| goto out; |
| } |
| } |
| |
| out: |
| sshbuf_free(b); |
| free(originator_address); |
| free(listen_address); |
| return c; |
| } |
| |
| static Channel * |
| client_request_forwarded_streamlocal(struct ssh *ssh, |
| const char *request_type, int rchan) |
| { |
| Channel *c = NULL; |
| char *listen_path; |
| int r; |
| |
| /* Get the remote path. */ |
| if ((r = sshpkt_get_cstring(ssh, &listen_path, NULL)) != 0 || |
| (r = sshpkt_get_string(ssh, NULL, NULL)) != 0 || /* reserved */ |
| (r = sshpkt_get_end(ssh)) != 0) |
| fatal("%s: parse packet: %s", __func__, ssh_err(r)); |
| |
| debug("%s: request: %s", __func__, listen_path); |
| |
| c = channel_connect_by_listen_path(ssh, listen_path, |
| "forwarded-streamlocal@openssh.com", "forwarded-streamlocal"); |
| free(listen_path); |
| return c; |
| } |
| |
| static Channel * |
| client_request_x11(struct ssh *ssh, const char *request_type, int rchan) |
| { |
| Channel *c = NULL; |
| char *originator; |
| u_int originator_port; |
| int r, 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; |
| } |
| if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) { |
| verbose("Rejected X11 connection after ForwardX11Timeout " |
| "expired"); |
| return NULL; |
| } |
| if ((r = sshpkt_get_cstring(ssh, &originator, NULL)) != 0 || |
| (r = sshpkt_get_u32(ssh, &originator_port)) != 0 || |
| (r = sshpkt_get_end(ssh)) != 0) |
| fatal("%s: parse packet: %s", __func__, ssh_err(r)); |
| /* XXX check permission */ |
| /* XXX range check originator port? */ |
| debug("client_request_x11: request from %s %u", originator, |
| originator_port); |
| free(originator); |
| sock = x11_connect_display(ssh); |
| if (sock < 0) |
| return NULL; |
| c = channel_new(ssh, "x11", |
| SSH_CHANNEL_X11_OPEN, sock, sock, -1, |
| CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); |
| c->force_drain = 1; |
| return c; |
| } |
| |
| static Channel * |
| client_request_agent(struct ssh *ssh, const char *request_type, int rchan) |
| { |
| Channel *c = NULL; |
| int r, 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; |
| } |
| if (forward_agent_sock_path == NULL) { |
| r = ssh_get_authentication_socket(&sock); |
| } else { |
| r = ssh_get_authentication_socket_path(forward_agent_sock_path, &sock); |
| } |
| if (r != 0) { |
| if (r != SSH_ERR_AGENT_NOT_PRESENT) |
| debug("%s: ssh_get_authentication_socket: %s", |
| __func__, ssh_err(r)); |
| return NULL; |
| } |
| c = channel_new(ssh, "authentication agent connection", |
| SSH_CHANNEL_OPEN, sock, sock, -1, |
| CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, |
| "authentication agent connection", 1); |
| c->force_drain = 1; |
| return c; |
| } |
| |
| char * |
| client_request_tun_fwd(struct ssh *ssh, int tun_mode, |
| int local_tun, int remote_tun) |
| { |
| Channel *c; |
| int r, fd; |
| char *ifname = NULL; |
| |
| if (tun_mode == SSH_TUNMODE_NO) |
| return 0; |
| |
| debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); |
| |
| /* Open local tunnel device */ |
| if ((fd = tun_open(local_tun, tun_mode, &ifname)) == -1) { |
| error("Tunnel device open failed."); |
| return NULL; |
| } |
| debug("Tunnel forwarding using interface %s", ifname); |
| |
| c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1, |
| CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); |
| c->datagram = 1; |
| |
| #if defined(SSH_TUN_FILTER) |
| if (options.tun_open == SSH_TUNMODE_POINTOPOINT) |
| channel_register_filter(ssh, c->self, sys_tun_infilter, |
| sys_tun_outfilter, NULL, NULL); |
| #endif |
| |
| if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || |
| (r = sshpkt_put_cstring(ssh, "tun@openssh.com")) != 0 || |
| (r = sshpkt_put_u32(ssh, c->self)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->local_window_max)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || |
| (r = sshpkt_put_u32(ssh, tun_mode)) != 0 || |
| (r = sshpkt_put_u32(ssh, remote_tun)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| sshpkt_fatal(ssh, r, "%s: send reply", __func__); |
| |
| return ifname; |
| } |
| |
| /* XXXX move to generic input handler */ |
| static int |
| client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| Channel *c = NULL; |
| char *ctype = NULL; |
| int r; |
| u_int rchan; |
| size_t len; |
| u_int rmaxpack, rwindow; |
| |
| if ((r = sshpkt_get_cstring(ssh, &ctype, &len)) != 0 || |
| (r = sshpkt_get_u32(ssh, &rchan)) != 0 || |
| (r = sshpkt_get_u32(ssh, &rwindow)) != 0 || |
| (r = sshpkt_get_u32(ssh, &rmaxpack)) != 0) |
| goto out; |
| |
| 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(ssh, ctype, rchan, rwindow, |
| rmaxpack); |
| } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) { |
| c = client_request_forwarded_streamlocal(ssh, ctype, rchan); |
| } else if (strcmp(ctype, "x11") == 0) { |
| c = client_request_x11(ssh, ctype, rchan); |
| } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { |
| c = client_request_agent(ssh, ctype, rchan); |
| } |
| if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { |
| debug3("proxied to downstream: %s", ctype); |
| } else if (c != NULL) { |
| debug("confirm %s", ctype); |
| c->remote_id = rchan; |
| c->have_remote_id = 1; |
| c->remote_window = rwindow; |
| c->remote_maxpacket = rmaxpack; |
| if (c->type != SSH_CHANNEL_CONNECTING) { |
| if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->self)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| sshpkt_fatal(ssh, r, "%s: send reply", __func__); |
| } |
| } else { |
| debug("failure %s", ctype); |
| if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || |
| (r = sshpkt_put_u32(ssh, rchan)) != 0 || |
| (r = sshpkt_put_u32(ssh, SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED)) != 0 || |
| (r = sshpkt_put_cstring(ssh, "open failed")) != 0 || |
| (r = sshpkt_put_cstring(ssh, "")) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| sshpkt_fatal(ssh, r, "%s: send failure", __func__); |
| } |
| r = 0; |
| out: |
| free(ctype); |
| return r; |
| } |
| |
| static int |
| client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| Channel *c = NULL; |
| char *rtype = NULL; |
| u_char reply; |
| u_int id, exitval; |
| int r, success = 0; |
| |
| if ((r = sshpkt_get_u32(ssh, &id)) != 0) |
| return r; |
| if (id <= INT_MAX) |
| c = channel_lookup(ssh, id); |
| if (channel_proxy_upstream(c, type, seq, ssh)) |
| return 0; |
| if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 || |
| (r = sshpkt_get_u8(ssh, &reply)) != 0) |
| goto out; |
| |
| debug("client_input_channel_req: channel %u rtype %s reply %d", |
| id, rtype, reply); |
| |
| if (c == NULL) { |
| error("client_input_channel_req: channel %d: " |
| "unknown channel", id); |
| } else if (strcmp(rtype, "eow@openssh.com") == 0) { |
| if ((r = sshpkt_get_end(ssh)) != 0) |
| goto out; |
| chan_rcvd_eow(ssh, c); |
| } else if (strcmp(rtype, "exit-status") == 0) { |
| if ((r = sshpkt_get_u32(ssh, &exitval)) != 0) |
| goto out; |
| if (c->ctl_chan != -1) { |
| mux_exit_message(ssh, c, exitval); |
| success = 1; |
| } else if ((int)id == session_ident) { |
| /* Record exit value of local session */ |
| success = 1; |
| exit_status = exitval; |
| } else { |
| /* Probably for a mux channel that has already closed */ |
| debug("%s: no sink for exit-status on channel %d", |
| __func__, id); |
| } |
| if ((r = sshpkt_get_end(ssh)) != 0) |
| goto out; |
| } |
| if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) { |
| if (!c->have_remote_id) |
| fatal("%s: channel %d: no remote_id", |
| __func__, c->self); |
| if ((r = sshpkt_start(ssh, success ? |
| SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE)) != 0 || |
| (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| sshpkt_fatal(ssh, r, "%s: send failure", __func__); |
| } |
| r = 0; |
| out: |
| free(rtype); |
| return r; |
| } |
| |
| struct hostkeys_update_ctx { |
| /* The hostname and (optionally) IP address string for the server */ |
| char *host_str, *ip_str; |
| |
| /* |
| * Keys received from the server and a flag for each indicating |
| * whether they already exist in known_hosts. |
| * keys_seen is filled in by hostkeys_find() and later (for new |
| * keys) by client_global_hostkeys_private_confirm(). |
| */ |
| struct sshkey **keys; |
| int *keys_seen; |
| size_t nkeys, nnew; |
| |
| /* |
| * Keys that are in known_hosts, but were not present in the update |
| * from the server (i.e. scheduled to be deleted). |
| * Filled in by hostkeys_find(). |
| */ |
| struct sshkey **old_keys; |
| size_t nold; |
| }; |
| |
| static void |
| hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx) |
| { |
| size_t i; |
| |
| if (ctx == NULL) |
| return; |
| for (i = 0; i < ctx->nkeys; i++) |
| sshkey_free(ctx->keys[i]); |
| free(ctx->keys); |
| free(ctx->keys_seen); |
| for (i = 0; i < ctx->nold; i++) |
| sshkey_free(ctx->old_keys[i]); |
| free(ctx->old_keys); |
| free(ctx->host_str); |
| free(ctx->ip_str); |
| free(ctx); |
| } |
| |
| static int |
| hostkeys_find(struct hostkey_foreach_line *l, void *_ctx) |
| { |
| struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; |
| size_t i; |
| struct sshkey **tmp; |
| |
| if (l->status != HKF_STATUS_MATCHED || l->key == NULL) |
| return 0; |
| |
| /* Mark off keys we've already seen for this host */ |
| for (i = 0; i < ctx->nkeys; i++) { |
| if (sshkey_equal(l->key, ctx->keys[i])) { |
| debug3("%s: found %s key at %s:%ld", __func__, |
| sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); |
| ctx->keys_seen[i] = 1; |
| return 0; |
| } |
| } |
| /* This line contained a key that not offered by the server */ |
| debug3("%s: deprecated %s key at %s:%ld", __func__, |
| sshkey_ssh_name(l->key), l->path, l->linenum); |
| if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1, |
| sizeof(*ctx->old_keys))) == NULL) |
| fatal("%s: recallocarray failed nold = %zu", |
| __func__, ctx->nold); |
| ctx->old_keys = tmp; |
| ctx->old_keys[ctx->nold++] = l->key; |
| l->key = NULL; |
| |
| return 0; |
| } |
| |
| static void |
| hostkey_change_preamble(LogLevel loglevel) |
| { |
| do_log2(loglevel, "The server has updated its host keys."); |
| do_log2(loglevel, "These changes were verified by the server's " |
| "existing trusted key."); |
| } |
| |
| static void |
| update_known_hosts(struct hostkeys_update_ctx *ctx) |
| { |
| int r, was_raw = 0, first = 1; |
| int asking = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK; |
| LogLevel loglevel = asking ? SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE; |
| char *fp, *response; |
| size_t i; |
| struct stat sb; |
| |
| for (i = 0; i < ctx->nkeys; i++) { |
| if (ctx->keys_seen[i] != 2) |
| continue; |
| if ((fp = sshkey_fingerprint(ctx->keys[i], |
| options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) |
| fatal("%s: sshkey_fingerprint failed", __func__); |
| if (first && asking) |
| hostkey_change_preamble(loglevel); |
| do_log2(loglevel, "Learned new hostkey: %s %s", |
| sshkey_type(ctx->keys[i]), fp); |
| first = 0; |
| free(fp); |
| } |
| for (i = 0; i < ctx->nold; i++) { |
| if ((fp = sshkey_fingerprint(ctx->old_keys[i], |
| options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) |
| fatal("%s: sshkey_fingerprint failed", __func__); |
| if (first && asking) |
| hostkey_change_preamble(loglevel); |
| do_log2(loglevel, "Deprecating obsolete hostkey: %s %s", |
| sshkey_type(ctx->old_keys[i]), fp); |
| first = 0; |
| free(fp); |
| } |
| if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) { |
| if (get_saved_tio() != NULL) { |
| leave_raw_mode(1); |
| was_raw = 1; |
| } |
| response = NULL; |
| for (i = 0; !quit_pending && i < 3; i++) { |
| free(response); |
| response = read_passphrase("Accept updated hostkeys? " |
| "(yes/no): ", RP_ECHO); |
| if (strcasecmp(response, "yes") == 0) |
| break; |
| else if (quit_pending || response == NULL || |
| strcasecmp(response, "no") == 0) { |
| options.update_hostkeys = 0; |
| break; |
| } else { |
| do_log2(loglevel, "Please enter " |
| "\"yes\" or \"no\""); |
| } |
| } |
| if (quit_pending || i >= 3 || response == NULL) |
| options.update_hostkeys = 0; |
| free(response); |
| if (was_raw) |
| enter_raw_mode(1); |
| } |
| if (options.update_hostkeys == 0) |
| return; |
| /* |
| * Now that all the keys are verified, we can go ahead and replace |
| * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't |
| * cancel the operation). |
| */ |
| for (i = 0; i < options.num_user_hostfiles; i++) { |
| /* |
| * NB. keys are only added to hostfiles[0], for the rest we |
| * just delete the hostname entries. |
| */ |
| if (stat(options.user_hostfiles[i], &sb) != 0) { |
| if (errno == ENOENT) { |
| debug("%s: known hosts file %s does not exist", |
| __func__, strerror(errno)); |
| } else { |
| error("%s: known hosts file %s inaccessible", |
| __func__, strerror(errno)); |
| } |
| continue; |
| } |
| if ((r = hostfile_replace_entries(options.user_hostfiles[i], |
| ctx->host_str, ctx->ip_str, |
| i == 0 ? ctx->keys : NULL, i == 0 ? ctx->nkeys : 0, |
| options.hash_known_hosts, 0, |
| options.fingerprint_hash)) != 0) { |
| error("%s: hostfile_replace_entries failed for %s: %s", |
| __func__, options.user_hostfiles[i], ssh_err(r)); |
| } |
| } |
| } |
| |
| static void |
| client_global_hostkeys_private_confirm(struct ssh *ssh, int type, |
| u_int32_t seq, void *_ctx) |
| { |
| struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; |
| size_t i, ndone; |
| struct sshbuf *signdata; |
| int r, kexsigtype, use_kexsigtype; |
| const u_char *sig; |
| size_t siglen; |
| |
| if (ctx->nnew == 0) |
| fatal("%s: ctx->nnew == 0", __func__); /* sanity */ |
| if (type != SSH2_MSG_REQUEST_SUCCESS) { |
| error("Server failed to confirm ownership of " |
| "private host keys"); |
| hostkeys_update_ctx_free(ctx); |
| return; |
| } |
| kexsigtype = sshkey_type_plain( |
| sshkey_type_from_name(ssh->kex->hostkey_alg)); |
| |
| if ((signdata = sshbuf_new()) == NULL) |
| fatal("%s: sshbuf_new failed", __func__); |
| /* Don't want to accidentally accept an unbound signature */ |
| if (ssh->kex->session_id_len == 0) |
| fatal("%s: ssh->kex->session_id_len == 0", __func__); |
| /* |
| * Expect a signature for each of the ctx->nnew private keys we |
| * haven't seen before. They will be in the same order as the |
| * ctx->keys where the corresponding ctx->keys_seen[i] == 0. |
| */ |
| for (ndone = i = 0; i < ctx->nkeys; i++) { |
| if (ctx->keys_seen[i]) |
| continue; |
| /* Prepare data to be signed: session ID, unique string, key */ |
| sshbuf_reset(signdata); |
| if ( (r = sshbuf_put_cstring(signdata, |
| "hostkeys-prove-00@openssh.com")) != 0 || |
| (r = sshbuf_put_string(signdata, ssh->kex->session_id, |
| ssh->kex->session_id_len)) != 0 || |
| (r = sshkey_puts(ctx->keys[i], signdata)) != 0) |
| fatal("%s: failed to prepare signature: %s", |
| __func__, ssh_err(r)); |
| /* Extract and verify signature */ |
| if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) { |
| error("%s: couldn't parse message: %s", |
| __func__, ssh_err(r)); |
| goto out; |
| } |
| /* |
| * For RSA keys, prefer to use the signature type negotiated |
| * during KEX to the default (SHA1). |
| */ |
| use_kexsigtype = kexsigtype == KEY_RSA && |
| sshkey_type_plain(ctx->keys[i]->type) == KEY_RSA; |
| if ((r = sshkey_verify(ctx->keys[i], sig, siglen, |
| sshbuf_ptr(signdata), sshbuf_len(signdata), |
| use_kexsigtype ? ssh->kex->hostkey_alg : NULL, 0, |
| NULL)) != 0) { |
| error("%s: server gave bad signature for %s key %zu", |
| __func__, sshkey_type(ctx->keys[i]), i); |
| goto out; |
| } |
| /* Key is good. Mark it as 'seen' */ |
| ctx->keys_seen[i] = 2; |
| ndone++; |
| } |
| if (ndone != ctx->nnew) |
| fatal("%s: ndone != ctx->nnew (%zu / %zu)", __func__, |
| ndone, ctx->nnew); /* Shouldn't happen */ |
| if ((r = sshpkt_get_end(ssh)) != 0) { |
| error("%s: protocol error", __func__); |
| goto out; |
| } |
| |
| /* Make the edits to known_hosts */ |
| update_known_hosts(ctx); |
| out: |
| hostkeys_update_ctx_free(ctx); |
| } |
| |
| /* |
| * Returns non-zero if the key is accepted by HostkeyAlgorithms. |
| * Made slightly less trivial by the multiple RSA signature algorithm names. |
| */ |
| static int |
| key_accepted_by_hostkeyalgs(const struct sshkey *key) |
| { |
| const char *ktype = sshkey_ssh_name(key); |
| const char *hostkeyalgs = options.hostkeyalgorithms; |
| |
| if (key == NULL || key->type == KEY_UNSPEC) |
| return 0; |
| if (key->type == KEY_RSA && |
| (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 || |
| match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1)) |
| return 1; |
| return match_pattern_list(ktype, hostkeyalgs, 0) == 1; |
| } |
| |
| /* |
| * Handle hostkeys-00@openssh.com global request to inform the client of all |
| * the server's hostkeys. The keys are checked against the user's |
| * HostkeyAlgorithms preference before they are accepted. |
| */ |
| static int |
| client_input_hostkeys(struct ssh *ssh) |
| { |
| const u_char *blob = NULL; |
| size_t i, len = 0; |
| struct sshbuf *buf = NULL; |
| struct sshkey *key = NULL, **tmp; |
| int r; |
| char *fp; |
| static int hostkeys_seen = 0; /* XXX use struct ssh */ |
| extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */ |
| struct hostkeys_update_ctx *ctx = NULL; |
| |
| if (hostkeys_seen) |
| fatal("%s: server already sent hostkeys", __func__); |
| if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK && |
| options.batch_mode) |
| return 1; /* won't ask in batchmode, so don't even try */ |
| if (!options.update_hostkeys || options.num_user_hostfiles <= 0) |
| return 1; |
| |
| ctx = xcalloc(1, sizeof(*ctx)); |
| while (ssh_packet_remaining(ssh) > 0) { |
| sshkey_free(key); |
| key = NULL; |
| if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) { |
| error("%s: couldn't parse message: %s", |
| __func__, ssh_err(r)); |
| goto out; |
| } |
| if ((r = sshkey_from_blob(blob, len, &key)) != 0) { |
| do_log2(r == SSH_ERR_KEY_TYPE_UNKNOWN ? |
| SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_ERROR, |
| "%s: parse key: %s", __func__, ssh_err(r)); |
| continue; |
| } |
| fp = sshkey_fingerprint(key, options.fingerprint_hash, |
| SSH_FP_DEFAULT); |
| debug3("%s: received %s key %s", __func__, |
| sshkey_type(key), fp); |
| free(fp); |
| |
| if (!key_accepted_by_hostkeyalgs(key)) { |
| debug3("%s: %s key not permitted by HostkeyAlgorithms", |
| __func__, sshkey_ssh_name(key)); |
| continue; |
| } |
| /* Skip certs */ |
| if (sshkey_is_cert(key)) { |
| debug3("%s: %s key is a certificate; skipping", |
| __func__, sshkey_ssh_name(key)); |
| continue; |
| } |
| /* Ensure keys are unique */ |
| for (i = 0; i < ctx->nkeys; i++) { |
| if (sshkey_equal(key, ctx->keys[i])) { |
| error("%s: received duplicated %s host key", |
| __func__, sshkey_ssh_name(key)); |
| goto out; |
| } |
| } |
| /* Key is good, record it */ |
| if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1, |
| sizeof(*ctx->keys))) == NULL) |
| fatal("%s: recallocarray failed nkeys = %zu", |
| __func__, ctx->nkeys); |
| ctx->keys = tmp; |
| ctx->keys[ctx->nkeys++] = key; |
| key = NULL; |
| } |
| |
| if (ctx->nkeys == 0) { |
| debug("%s: server sent no hostkeys", __func__); |
| goto out; |
| } |
| |
| if ((ctx->keys_seen = calloc(ctx->nkeys, |
| sizeof(*ctx->keys_seen))) == NULL) |
| fatal("%s: calloc failed", __func__); |
| |
| get_hostfile_hostname_ipaddr(host, |
| options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL, |
| options.port, &ctx->host_str, |
| options.check_host_ip ? &ctx->ip_str : NULL); |
| |
| /* Find which keys we already know about. */ |
| for (i = 0; i < options.num_user_hostfiles; i++) { |
| debug("%s: searching %s for %s / %s", __func__, |
| options.user_hostfiles[i], ctx->host_str, |
| ctx->ip_str ? ctx->ip_str : "(none)"); |
| if ((r = hostkeys_foreach(options.user_hostfiles[i], |
| hostkeys_find, ctx, ctx->host_str, ctx->ip_str, |
| HKF_WANT_PARSE_KEY|HKF_WANT_MATCH)) != 0) { |
| if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) { |
| debug("%s: hostkeys file %s does not exist", |
| __func__, options.user_hostfiles[i]); |
| continue; |
| } |
| error("%s: hostkeys_foreach failed for %s: %s", |
| __func__, options.user_hostfiles[i], ssh_err(r)); |
| goto out; |
| } |
| } |
| |
| /* Figure out if we have any new keys to add */ |
| ctx->nnew = 0; |
| for (i = 0; i < ctx->nkeys; i++) { |
| if (!ctx->keys_seen[i]) |
| ctx->nnew++; |
| } |
| |
| debug3("%s: %zu keys from server: %zu new, %zu retained. %zu to remove", |
| __func__, ctx->nkeys, ctx->nnew, ctx->nkeys - ctx->nnew, ctx->nold); |
| |
| if (ctx->nnew == 0 && ctx->nold != 0) { |
| /* We have some keys to remove. Just do it. */ |
| update_known_hosts(ctx); |
| } else if (ctx->nnew != 0) { |
| /* |
| * We have received hitherto-unseen keys from the server. |
| * Ask the server to confirm ownership of the private halves. |
| */ |
| debug3("%s: asking server to prove ownership for %zu keys", |
| __func__, ctx->nnew); |
| if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || |
| (r = sshpkt_put_cstring(ssh, |
| "hostkeys-prove-00@openssh.com")) != 0 || |
| (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */ |
| fatal("%s: cannot prepare packet: %s", |
| __func__, ssh_err(r)); |
| if ((buf = sshbuf_new()) == NULL) |
| fatal("%s: sshbuf_new", __func__); |
| for (i = 0; i < ctx->nkeys; i++) { |
| if (ctx->keys_seen[i]) |
| continue; |
| sshbuf_reset(buf); |
| if ((r = sshkey_putb(ctx->keys[i], buf)) != 0) |
| fatal("%s: sshkey_putb: %s", |
| __func__, ssh_err(r)); |
| if ((r = sshpkt_put_stringb(ssh, buf)) != 0) |
| fatal("%s: sshpkt_put_string: %s", |
| __func__, ssh_err(r)); |
| } |
| if ((r = sshpkt_send(ssh)) != 0) |
| fatal("%s: sshpkt_send: %s", __func__, ssh_err(r)); |
| client_register_global_confirm( |
| client_global_hostkeys_private_confirm, ctx); |
| ctx = NULL; /* will be freed in callback */ |
| } |
| |
| /* Success */ |
| out: |
| hostkeys_update_ctx_free(ctx); |
| sshkey_free(key); |
| sshbuf_free(buf); |
| /* |
| * NB. Return success for all cases. The server doesn't need to know |
| * what the client does with its hosts file. |
| */ |
| return 1; |
| } |
| |
| static int |
| client_input_global_request(int type, u_int32_t seq, struct ssh *ssh) |
| { |
| char *rtype; |
| u_char want_reply; |
| int r, success = 0; |
| |
| if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 || |
| (r = sshpkt_get_u8(ssh, &want_reply)) != 0) |
| goto out; |
| debug("client_input_global_request: rtype %s want_reply %d", |
| rtype, want_reply); |
| if (strcmp(rtype, "hostkeys-00@openssh.com") == 0) |
| success = client_input_hostkeys(ssh); |
| if (want_reply) { |
| if ((r = sshpkt_start(ssh, success ? SSH2_MSG_REQUEST_SUCCESS : |
| SSH2_MSG_REQUEST_FAILURE)) != 0 || |
| (r = sshpkt_send(ssh)) != 0 || |
| (r = ssh_packet_write_wait(ssh)) != 0) |
| goto out; |
| } |
| r = 0; |
| out: |
| free(rtype); |
| return r; |
| } |
| |
| void |
| client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem, |
| const char *term, struct termios *tiop, int in_fd, struct sshbuf *cmd, |
| char **env) |
| { |
| int i, j, matched, len, r; |
| char *name, *val; |
| Channel *c = NULL; |
| |
| debug2("%s: id %d", __func__, id); |
| |
| if ((c = channel_lookup(ssh, id)) == NULL) |
| fatal("%s: channel %d: unknown channel", __func__, id); |
| |
| ssh_packet_set_interactive(ssh, want_tty, |
| options.ip_qos_interactive, options.ip_qos_bulk); |
| |
| if (want_tty) { |
| struct winsize ws; |
| |
| /* Store window size in the packet. */ |
| if (ioctl(in_fd, TIOCGWINSZ, &ws) == -1) |
| memset(&ws, 0, sizeof(ws)); |
| |
| channel_request_start(ssh, id, "pty-req", 1); |
| client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY); |
| if ((r = sshpkt_put_cstring(ssh, term != NULL ? term : "")) |
| != 0 || |
| (r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || |
| (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || |
| (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || |
| (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0) |
| fatal("%s: build packet: %s", __func__, ssh_err(r)); |
| if (tiop == NULL) |
| tiop = get_saved_tio(); |
| ssh_tty_make_modes(ssh, -1, tiop); |
| if ((r = sshpkt_send(ssh)) != 0) |
| fatal("%s: send packet: %s", __func__, ssh_err(r)); |
| /* XXX wait for reply */ |
| c->client_tty = 1; |
| } |
| |
| /* Transfer any environment variables from client to server */ |
| if (options.num_send_env != 0 && env != NULL) { |
| 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(ssh, id, "env", 0); |
| if ((r = sshpkt_put_cstring(ssh, name)) != 0 || |
| (r = sshpkt_put_cstring(ssh, val)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) { |
| fatal("%s: send packet: %s", |
| __func__, ssh_err(r)); |
| } |
| free(name); |
| } |
| } |
| for (i = 0; i < options.num_setenv; i++) { |
| /* Split */ |
| name = xstrdup(options.setenv[i]); |
| if ((val = strchr(name, '=')) == NULL) { |
| free(name); |
| continue; |
| } |
| *val++ = '\0'; |
| |
| debug("Setting env %s = %s", name, val); |
| channel_request_start(ssh, id, "env", 0); |
| if ((r = sshpkt_put_cstring(ssh, name)) != 0 || |
| (r = sshpkt_put_cstring(ssh, val)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: send packet: %s", __func__, ssh_err(r)); |
| free(name); |
| } |
| |
| len = sshbuf_len(cmd); |
| if (len > 0) { |
| if (len > 900) |
| len = 900; |
| if (want_subsystem) { |
| debug("Sending subsystem: %.*s", |
| len, (const u_char*)sshbuf_ptr(cmd)); |
| channel_request_start(ssh, id, "subsystem", 1); |
| client_expect_confirm(ssh, id, "subsystem", |
| CONFIRM_CLOSE); |
| } else { |
| debug("Sending command: %.*s", |
| len, (const u_char*)sshbuf_ptr(cmd)); |
| channel_request_start(ssh, id, "exec", 1); |
| client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE); |
| } |
| if ((r = sshpkt_put_stringb(ssh, cmd)) != 0 || |
| (r = sshpkt_send(ssh)) != 0) |
| fatal("%s: send command: %s", __func__, ssh_err(r)); |
| } else { |
| channel_request_start(ssh, id, "shell", 1); |
| client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE); |
| if ((r = sshpkt_send(ssh)) != 0) { |
| fatal("%s: send shell request: %s", |
| __func__, ssh_err(r)); |
| } |
| } |
| } |
| |
| static void |
| client_init_dispatch(struct ssh *ssh) |
| { |
| ssh_dispatch_init(ssh, &dispatch_protocol_error); |
| |
| ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); |
| ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_DATA, &channel_input_data); |
| ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); |
| ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); |
| ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); |
| ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); |
| ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); |
| ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); |
| ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); |
| ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); |
| ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); |
| ssh_dispatch_set(ssh, SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); |
| |
| /* rekeying */ |
| ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_input_kexinit); |
| |
| /* global request reply messages */ |
| ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); |
| ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); |
| } |
| |
| void |
| client_stop_mux(void) |
| { |
| if (options.control_path != NULL && muxserver_sock != -1) |
| unlink(options.control_path); |
| /* |
| * If we are in persist mode, or don't have a shell, signal that we |
| * should close when all active channels are closed. |
| */ |
| if (options.control_persist || no_shell_flag) { |
| session_closed = 1; |
| setproctitle("[stopped mux]"); |
| } |
| } |
| |
| /* client specific fatal cleanup */ |
| void |
| cleanup_exit(int i) |
| { |
| leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); |
| leave_non_blocking(); |
| if (options.control_path != NULL && muxserver_sock != -1) |
| unlink(options.control_path); |
| ssh_kill_proxy_command(); |
| _exit(i); |
| } |