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+/* $OpenBSD: clientloop.c,v 1.402 2023/11/24 00:31:30 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
+#ifdef HAVE_POLL_H
+#include <poll.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"
+
+/* Permitted RSA signature algorithms for UpdateHostkeys proofs */
+#define HOSTKEY_PROOF_RSA_ALGS "rsa-sha2-512,rsa-sha2-256"
+
+/* Uncertainty (in percent) of keystroke timing intervals */
+#define SSH_KEYSTROKE_TIMING_FUZZ 10
+
+/* import options */
+extern Options options;
+
+/* 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;
+
+/* 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 time_t x11_refuse_time; /* If >0, refuse x11 opens after this time. */
+static time_t server_alive_time; /* Time to do server_alive_check */
+static int hostkeys_update_complete;
+static int session_setup_complete;
+
+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 *);
+static void quit_message(const char *fmt, ...)
+ __attribute__((__format__ (printf, 1, 2)));
+
+static void
+quit_message(const char *fmt, ...)
+{
+ char *msg;
+ va_list args;
+ int r;
+
+ va_start(args, fmt);
+ xvasprintf(&msg, fmt, args);
+ va_end(args);
+
+ if ((r = sshbuf_putf(stderr_buffer, "%s\r\n", msg)) != 0)
+ fatal_fr(r, "sshbuf_putf");
+ free(msg);
+ quit_pending = 1;
+}
+
+/*
+ * 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 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;
+}
+
+/*
+ * 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_f("cancel scheduled exit");
+ 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_f("schedule exit in %d seconds",
+ 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_f("display name too long");
+ 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_f("mkdtemp: %s", strerror(errno));
+ return -1;
+ }
+ do_unlink = 1;
+ if ((r = snprintf(xauthfile, sizeof(xauthfile),
+ "%s/xauthfile", xauthdir)) < 0 ||
+ (size_t)r >= sizeof(xauthfile)) {
+ error_f("xauthfile path too long");
+ 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_f("xauth command: %s", cmd);
+
+ if (timeout != 0 && x11_refuse_time == 0) {
+ now = monotime() + 1;
+ if (SSH_TIME_T_MAX - timeout < now)
+ x11_refuse_time = SSH_TIME_T_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_f("changed");
+ 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);
+ freezero(gc, sizeof(*gc));
+ }
+
+ ssh_packet_set_alive_timeouts(ssh, 0);
+ return 0;
+}
+
+static void
+schedule_server_alive_check(void)
+{
+ if (options.server_alive_interval > 0)
+ server_alive_time = monotime() + options.server_alive_interval;
+}
+
+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_fr(r, "send packet");
+ /* Insert an empty placeholder to maintain ordering */
+ client_register_global_confirm(NULL, NULL);
+ schedule_server_alive_check();
+}
+
+/* Try to send a dummy keystroke */
+static int
+send_chaff(struct ssh *ssh)
+{
+ int r;
+
+ if ((ssh->kex->flags & KEX_HAS_PING) == 0)
+ return 0;
+ /* XXX probabilistically send chaff? */
+ /*
+ * a SSH2_MSG_CHANNEL_DATA payload is 9 bytes:
+ * 4 bytes channel ID + 4 bytes string length + 1 byte string data
+ * simulate that here.
+ */
+ if ((r = sshpkt_start(ssh, SSH2_MSG_PING)) != 0 ||
+ (r = sshpkt_put_cstring(ssh, "PING!")) != 0 ||
+ (r = sshpkt_send(ssh)) != 0)
+ fatal_fr(r, "send packet");
+ return 1;
+}
+
+/* Sets the next interval to send a keystroke or chaff packet */
+static void
+set_next_interval(const struct timespec *now, struct timespec *next_interval,
+ u_int interval_ms, int starting)
+{
+ struct timespec tmp;
+ long long interval_ns, fuzz_ns;
+ static long long rate_fuzz;
+
+ interval_ns = interval_ms * (1000LL * 1000);
+ fuzz_ns = (interval_ns * SSH_KEYSTROKE_TIMING_FUZZ) / 100;
+ /* Center fuzz around requested interval */
+ if (fuzz_ns > INT_MAX)
+ fuzz_ns = INT_MAX;
+ if (fuzz_ns > interval_ns) {
+ /* Shouldn't happen */
+ fatal_f("internal error: fuzz %u%% %lldns > interval %lldns",
+ SSH_KEYSTROKE_TIMING_FUZZ, fuzz_ns, interval_ns);
+ }
+ /*
+ * Randomise the keystroke/chaff intervals in two ways:
+ * 1. Each interval has some random jitter applied to make the
+ * interval-to-interval time unpredictable.
+ * 2. The overall interval rate is also randomly perturbed for each
+ * chaffing session to make the average rate unpredictable.
+ */
+ if (starting)
+ rate_fuzz = arc4random_uniform(fuzz_ns);
+ interval_ns -= fuzz_ns;
+ interval_ns += arc4random_uniform(fuzz_ns) + rate_fuzz;
+
+ tmp.tv_sec = interval_ns / (1000 * 1000 * 1000);
+ tmp.tv_nsec = interval_ns % (1000 * 1000 * 1000);
+
+ timespecadd(now, &tmp, next_interval);
+}
+
+/*
+ * Performs keystroke timing obfuscation. Returns non-zero if the
+ * output fd should be polled.
+ */
+static int
+obfuscate_keystroke_timing(struct ssh *ssh, struct timespec *timeout,
+ int channel_did_enqueue)
+{
+ static int active;
+ static struct timespec next_interval, chaff_until;
+ struct timespec now, tmp;
+ int just_started = 0, had_keystroke = 0;
+ static unsigned long long nchaff;
+ char *stop_reason = NULL;
+ long long n;
+
+ monotime_ts(&now);
+
+ if (options.obscure_keystroke_timing_interval <= 0)
+ return 1; /* disabled in config */
+
+ if (!channel_tty_open(ssh) || quit_pending) {
+ /* Stop if no channels left of we're waiting for one to close */
+ stop_reason = "no active channels";
+ } else if (ssh_packet_is_rekeying(ssh)) {
+ /* Stop if we're rekeying */
+ stop_reason = "rekeying started";
+ } else if (!ssh_packet_interactive_data_to_write(ssh) &&
+ ssh_packet_have_data_to_write(ssh)) {
+ /* Stop if the output buffer has more than a few keystrokes */
+ stop_reason = "output buffer filling";
+ } else if (active && channel_did_enqueue &&
+ ssh_packet_have_data_to_write(ssh)) {
+ /* Still in active mode and have a keystroke queued. */
+ had_keystroke = 1;
+ } else if (active) {
+ if (timespeccmp(&now, &chaff_until, >=)) {
+ /* Stop if there have been no keystrokes for a while */
+ stop_reason = "chaff time expired";
+ } else if (timespeccmp(&now, &next_interval, >=)) {
+ /* Otherwise if we were due to send, then send chaff */
+ if (send_chaff(ssh))
+ nchaff++;
+ }
+ }
+
+ if (stop_reason != NULL) {
+ if (active) {
+ debug3_f("stopping: %s (%llu chaff packets sent)",
+ stop_reason, nchaff);
+ active = 0;
+ }
+ return 1;
+ }
+
+ /*
+ * If we're in interactive mode, and only have a small amount
+ * of outbound data, then we assume that the user is typing
+ * interactively. In this case, start quantising outbound packets to
+ * fixed time intervals to hide inter-keystroke timing.
+ */
+ if (!active && ssh_packet_interactive_data_to_write(ssh) &&
+ channel_did_enqueue && ssh_packet_have_data_to_write(ssh)) {
+ debug3_f("starting: interval ~%dms",
+ options.obscure_keystroke_timing_interval);
+ just_started = had_keystroke = active = 1;
+ nchaff = 0;
+ set_next_interval(&now, &next_interval,
+ options.obscure_keystroke_timing_interval, 1);
+ }
+
+ /* Don't hold off if obfuscation inactive */
+ if (!active)
+ return 1;
+
+ if (had_keystroke) {
+ /*
+ * Arrange to send chaff packets for a random interval after
+ * the last keystroke was sent.
+ */
+ ms_to_timespec(&tmp, SSH_KEYSTROKE_CHAFF_MIN_MS +
+ arc4random_uniform(SSH_KEYSTROKE_CHAFF_RNG_MS));
+ timespecadd(&now, &tmp, &chaff_until);
+ }
+
+ ptimeout_deadline_monotime_tsp(timeout, &next_interval);
+
+ if (just_started)
+ return 1;
+
+ /* Don't arm output fd for poll until the timing interval has elapsed */
+ if (timespeccmp(&now, &next_interval, <))
+ return 0;
+
+ /* Calculate number of intervals missed since the last check */
+ n = (now.tv_sec - next_interval.tv_sec) * 1000LL * 1000 * 1000;
+ n += now.tv_nsec - next_interval.tv_nsec;
+ n /= options.obscure_keystroke_timing_interval * 1000LL * 1000;
+ n = (n < 0) ? 1 : n + 1;
+
+ /* Advance to the next interval */
+ set_next_interval(&now, &next_interval,
+ options.obscure_keystroke_timing_interval * n, 0);
+ return 1;
+}
+
+/*
+ * 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, struct pollfd **pfdp,
+ u_int *npfd_allocp, u_int *npfd_activep, int channel_did_enqueue,
+ sigset_t *sigsetp, int *conn_in_readyp, int *conn_out_readyp)
+{
+ struct timespec timeout;
+ int ret, oready;
+ u_int p;
+
+ *conn_in_readyp = *conn_out_readyp = 0;
+
+ /* Prepare channel poll. First two pollfd entries are reserved */
+ ptimeout_init(&timeout);
+ channel_prepare_poll(ssh, pfdp, npfd_allocp, npfd_activep, 2, &timeout);
+ if (*npfd_activep < 2)
+ fatal_f("bad npfd %u", *npfd_activep); /* shouldn't happen */
+
+ /* channel_prepare_poll could have closed the last channel */
+ if (session_closed && !channel_still_open(ssh) &&
+ !ssh_packet_have_data_to_write(ssh)) {
+ /* clear events since we did not call poll() */
+ for (p = 0; p < *npfd_activep; p++)
+ (*pfdp)[p].revents = 0;
+ return;
+ }
+
+ oready = obfuscate_keystroke_timing(ssh, &timeout, channel_did_enqueue);
+
+ /* Monitor server connection on reserved pollfd entries */
+ (*pfdp)[0].fd = connection_in;
+ (*pfdp)[0].events = POLLIN;
+ (*pfdp)[1].fd = connection_out;
+ (*pfdp)[1].events = (oready && ssh_packet_have_data_to_write(ssh)) ?
+ POLLOUT : 0;
+
+ /*
+ * Wait for something to happen. This will suspend the process until
+ * some polled descriptor can be read, written, or has some other
+ * event pending, or a timeout expires.
+ */
+ set_control_persist_exit_time(ssh);
+ if (control_persist_exit_time > 0)
+ ptimeout_deadline_monotime(&timeout, control_persist_exit_time);
+ if (options.server_alive_interval > 0)
+ ptimeout_deadline_monotime(&timeout, server_alive_time);
+ if (options.rekey_interval > 0 && !ssh_packet_is_rekeying(ssh)) {
+ ptimeout_deadline_sec(&timeout,
+ ssh_packet_get_rekey_timeout(ssh));
+ }
+
+ ret = ppoll(*pfdp, *npfd_activep, ptimeout_get_tsp(&timeout), sigsetp);
+
+ if (ret == -1) {
+ /*
+ * We have to clear the events because we return.
+ * We have to return, because the mainloop checks for the flags
+ * set by the signal handlers.
+ */
+ for (p = 0; p < *npfd_activep; p++)
+ (*pfdp)[p].revents = 0;
+ if (errno == EINTR)
+ return;
+ /* Note: we might still have data in the buffers. */
+ quit_message("poll: %s", strerror(errno));
+ return;
+ }
+
+ *conn_in_readyp = (*pfdp)[0].revents != 0;
+ *conn_out_readyp = (*pfdp)[1].revents != 0;
+
+ if (options.server_alive_interval > 0 && !*conn_in_readyp &&
+ monotime() >= server_alive_time) {
+ /*
+ * ServerAlive check is needed. We can't rely on the poll
+ * timing out since traffic on the client side such as port
+ * forwards can keep waking it up.
+ */
+ 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)
+{
+ int r;
+
+ /*
+ * Read input from the server, and add any such data to the buffer of
+ * the packet subsystem.
+ */
+ schedule_server_alive_check();
+ if ((r = ssh_packet_process_read(ssh, connection_in)) == 0)
+ return; /* success */
+ if (r == SSH_ERR_SYSTEM_ERROR) {
+ if (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK)
+ return;
+ if (errno == EPIPE) {
+ quit_message("Connection to %s closed by remote host.",
+ host);
+ return;
+ }
+ }
+ quit_message("Read from remote host %s: %s", host, ssh_err(r));
+}
+
+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) {
+ debug3_f("channel %d: mux request: %s", c->self,
+ cr->request_type);
+ if ((r = sshbuf_put(c->extended, errmsg,
+ strlen(errmsg))) != 0)
+ fatal_fr(r, "sshbuf_put");
+ } 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_f("last_gc->ref_count = %d",
+ 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);
+}
+
+/*
+ * Returns non-zero if the client is able to handle a hostkeys-00@openssh.com
+ * hostkey update request.
+ */
+static int
+can_update_hostkeys(void)
+{
+ if (hostkeys_update_complete)
+ return 0;
+ if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK &&
+ options.batch_mode)
+ return 0; /* won't ask in batchmode, so don't even try */
+ if (!options.update_hostkeys || options.num_user_hostfiles <= 0)
+ return 0;
+ return 1;
+}
+
+static void
+client_repledge(void)
+{
+ debug3_f("enter");
+
+ /* Might be able to tighten pledge now that session is established */
+ if (options.control_master || options.control_path != NULL ||
+ options.forward_x11 || options.fork_after_authentication ||
+ can_update_hostkeys() ||
+ (session_ident != -1 && !session_setup_complete)) {
+ /* Can't tighten */
+ return;
+ }
+ /*
+ * LocalCommand and UpdateHostkeys have finished, so can get rid of
+ * filesystem.
+ *
+ * XXX protocol allows a server can to change hostkeys during the
+ * connection at rekey time that could trigger a hostkeys update
+ * but AFAIK no implementations support this. Could improve by
+ * forcing known_hosts to be read-only or via unveil(2).
+ */
+ if (options.num_local_forwards != 0 ||
+ options.num_remote_forwards != 0 ||
+ options.num_permitted_remote_opens != 0 ||
+ options.enable_escape_commandline != 0) {
+ /* rfwd needs inet */
+ debug("pledge: network");
+ if (pledge("stdio unix inet dns proc tty", NULL) == -1)
+ fatal_f("pledge(): %s", strerror(errno));
+ } else if (options.forward_agent != 0) {
+ /* agent forwarding needs to open $SSH_AUTH_SOCK at will */
+ debug("pledge: agent");
+ if (pledge("stdio unix proc tty", NULL) == -1)
+ fatal_f("pledge(): %s", strerror(errno));
+ } else {
+ debug("pledge: fork");
+ if (pledge("stdio proc tty", NULL) == -1)
+ fatal_f("pledge(): %s", strerror(errno));
+ }
+ /* XXX further things to do:
+ *
+ * - might be able to get rid of proc if we kill ~^Z
+ * - ssh -N (no session)
+ * - stdio forwarding
+ * - sessions without tty
+ */
+}
+
+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 {
+ /* -R specs can be both dynamic or not, so check both. */
+ if (remote) {
+ if (!parse_forward(&fwd, s, 0, remote) &&
+ !parse_forward(&fwd, s, 1, remote)) {
+ logit("Bad remote forwarding specification.");
+ goto out;
+ }
+ } else if (!parse_forward(&fwd, s, dynamic, remote)) {
+ logit("Bad local 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 */
+#define SUPPRESS_NOCMDLINE 8 /* don't show when cmdline disabled*/
+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|SUPPRESS_NOCMDLINE},
+ {"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_fr(r, "sshbuf_putf");
+
+ suppress_flags =
+ (mux_client ? SUPPRESS_MUXCLIENT : 0) |
+ (mux_client ? 0 : SUPPRESS_MUXMASTER) |
+ (using_stderr ? 0 : SUPPRESS_SYSLOG) |
+ (options.enable_escape_commandline == 0 ? SUPPRESS_NOCMDLINE : 0);
+
+ 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_fr(r, "sshbuf_putf");
+ }
+
+ 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_fr(r, "sshbuf_putf");
+}
+
+/*
+ * 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;
+
+ if (c == NULL || c->filter_ctx == NULL || len <= 0)
+ return 0;
+
+ efc = (struct escape_filter_ctx *)c->filter_ctx;
+
+ 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_fr(r, "sshbuf_putf");
+ if (c && c->ctl_chan != -1) {
+ channel_force_close(ssh, c, 1);
+ 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_fr(r, "sshbuf_putf");
+ continue;
+ }
+ /* Suspend the program. Inform the user */
+ if ((r = sshbuf_putf(berr,
+ "%c^Z [suspend ssh]\r\n",
+ efc->escape_char)) != 0)
+ fatal_fr(r, "sshbuf_putf");
+
+ /* 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_fr(r, "sshbuf_putf");
+ channel_request_start(ssh, c->self, "break", 0);
+ if ((r = sshpkt_put_u32(ssh, 1000)) != 0 ||
+ (r = sshpkt_send(ssh)) != 0)
+ fatal_fr(r, "send packet");
+ continue;
+
+ case 'R':
+ if (ssh->compat & 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_fr(r, "sshbuf_putf");
+ 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_fr(r, "sshbuf_putf");
+ continue;
+
+ case '&':
+ if (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_fr(r, "sshbuf_putf");
+
+ /* 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_fr(r, "sshbuf_put_u8");
+ 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_fr(r, "sshbuf_putf");
+ s = channel_open_message(ssh);
+ if ((r = sshbuf_put(berr, s, strlen(s))) != 0)
+ fatal_fr(r, "sshbuf_put");
+ free(s);
+ continue;
+
+ case 'C':
+ if (c && c->ctl_chan != -1)
+ goto noescape;
+ if (options.enable_escape_commandline == 0) {
+ if ((r = sshbuf_putf(berr,
+ "commandline disabled\r\n")) != 0)
+ fatal_fr(r, "sshbuf_putf");
+ continue;
+ }
+ process_cmdline(ssh);
+ continue;
+
+ default:
+ if (ch != efc->escape_char) {
+ if ((r = sshbuf_put_u8(bin,
+ efc->escape_char)) != 0)
+ fatal_fr(r, "sshbuf_put_u8");
+ 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_fr(r, "sshbuf_put_u8");
+ 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, int force, 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)
+{
+ struct pollfd *pfd = NULL;
+ u_int npfd_alloc = 0, npfd_active = 0;
+ double start_time, total_time;
+ int channel_did_enqueue = 0, r, len;
+ u_int64_t ibytes, obytes;
+ int conn_in_ready, conn_out_ready;
+ sigset_t bsigset, osigset;
+
+ debug("Entering interactive session.");
+ session_ident = ssh2_chan_id;
+
+ 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_f("pledge(): %s", 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_f("pledge(): %s", strerror(errno));
+
+ } else if (options.update_hostkeys) {
+ debug("pledge: filesystem");
+ if (pledge("stdio rpath wpath cpath unix inet dns proc tty",
+ NULL) == -1)
+ fatal_f("pledge(): %s", strerror(errno));
+
+ } else if (!option_clear_or_none(options.proxy_command) ||
+ options.fork_after_authentication) {
+ debug("pledge: proc");
+ if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1)
+ fatal_f("pledge(): %s", strerror(errno));
+
+ } else {
+ debug("pledge: network");
+ if (pledge("stdio unix inet dns proc tty", NULL) == -1)
+ fatal_f("pledge(): %s", strerror(errno));
+ }
+
+ /* might be able to tighten now */
+ client_repledge();
+
+ 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);
+
+ quit_pending = 0;
+
+ /* Initialize buffer. */
+ if ((stderr_buffer = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+
+ 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);
+
+ 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);
+ }
+
+ schedule_server_alive_check();
+
+ if (sigemptyset(&bsigset) == -1 ||
+ sigaddset(&bsigset, SIGHUP) == -1 ||
+ sigaddset(&bsigset, SIGINT) == -1 ||
+ sigaddset(&bsigset, SIGQUIT) == -1 ||
+ sigaddset(&bsigset, SIGTERM) == -1)
+ error_f("bsigset setup: %s", strerror(errno));
+
+ /* Main loop of the client for the interactive session mode. */
+ while (!quit_pending) {
+ channel_did_enqueue = 0;
+
+ /* 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_fr(r, "kex_start_rekex");
+ 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_did_enqueue = 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);
+ }
+ /*
+ * Wait until we have something to do (something becomes
+ * available on one of the descriptors).
+ */
+ if (sigprocmask(SIG_BLOCK, &bsigset, &osigset) == -1)
+ error_f("bsigset sigprocmask: %s", strerror(errno));
+ if (quit_pending)
+ break;
+ client_wait_until_can_do_something(ssh, &pfd, &npfd_alloc,
+ &npfd_active, channel_did_enqueue, &osigset,
+ &conn_in_ready, &conn_out_ready);
+ if (sigprocmask(SIG_UNBLOCK, &bsigset, &osigset) == -1)
+ error_f("osigset sigprocmask: %s", strerror(errno));
+
+ if (quit_pending)
+ break;
+
+ /* Do channel operations. */
+ channel_after_poll(ssh, pfd, npfd_active);
+
+ /* Buffer input from the connection. */
+ if (conn_in_ready)
+ client_process_net_input(ssh);
+
+ if (quit_pending)
+ break;
+
+ /* A timeout may have triggered rekeying */
+ if ((r = ssh_packet_check_rekey(ssh)) != 0)
+ fatal_fr(r, "cannot start rekeying");
+
+ /*
+ * Send as much buffered packet data as possible to the
+ * sender.
+ */
+ if (conn_out_ready) {
+ 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(pfd);
+
+ /* 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_fr(r, "send disconnect");
+
+ channel_free_all(ssh);
+
+ if (have_pty)
+ leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
+
+ /*
+ * 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 (options.session_type == SESSION_TYPE_NONE &&
+ received_signal == SIGTERM) {
+ received_signal = 0;
+ exit_status = 0;
+ }
+
+ if (received_signal) {
+ verbose("Killed by signal %d.", (int) received_signal);
+ cleanup_exit(255);
+ }
+
+ /*
+ * In interactive mode (with pseudo tty) display a message indicating
+ * that the connection has been closed.
+ */
+ if (have_pty && options.log_level >= SYSLOG_LEVEL_INFO)
+ quit_message("Connection to %s closed.", host);
+
+ /* 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_fr(r, "sshbuf_consume");
+ }
+
+ /* Clear and free any buffers. */
+ 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_fr(r, "parse packet");
+
+ debug_f("listen %s port %d, originator %s port %d",
+ listen_address, listen_port, originator_address, originator_port);
+
+ if (listen_port > 0xffff)
+ error_f("invalid listen port");
+ else if (originator_port > 0xffff)
+ error_f("invalid originator port");
+ 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_f("alloc reply");
+ 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_fr(r, "compose for muxclient");
+ 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_fr(r, "parse packet");
+
+ debug_f("request: %s", 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 && 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_fr(r, "parse packet");
+ /* 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-connection",
+ 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_fr(r, "ssh_get_authentication_socket");
+ return NULL;
+ }
+ if ((r = ssh_agent_bind_hostkey(sock, ssh->kex->initial_hostkey,
+ ssh->kex->session_id, ssh->kex->initial_sig, 1)) == 0)
+ debug_f("bound agent to hostkey");
+ else
+ debug2_fr(r, "ssh_agent_bind_hostkey");
+
+ c = channel_new(ssh, "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_open_fn *cb, void *cbctx)
+{
+ 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-connection", 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 (cb != NULL)
+ channel_register_open_confirm(ssh, c->self, cb, cbctx);
+
+ 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_f("no sink for exit-status on channel %d",
+ 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_f("channel %d: no remote_id", 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_match is filled in by hostkeys_find() and later (for new
+ * keys) by client_global_hostkeys_prove_confirm().
+ */
+ struct sshkey **keys;
+ u_int *keys_match; /* mask of HKF_MATCH_* from hostfile.h */
+ int *keys_verified; /* flag for new keys verified by server */
+ size_t nkeys, nnew, nincomplete; /* total, new keys, incomplete match */
+
+ /*
+ * 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;
+
+ /* Various special cases. */
+ int complex_hostspec; /* wildcard or manual pattern-list host name */
+ int ca_available; /* saw CA key for this host */
+ int old_key_seen; /* saw old key with other name/addr */
+ int other_name_seen; /* saw key with other name/addr */
+};
+
+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_match);
+ free(ctx->keys_verified);
+ 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);
+}
+
+/*
+ * Returns non-zero if a known_hosts hostname list is not of a form that
+ * can be handled by UpdateHostkeys. These include wildcard hostnames and
+ * hostnames lists that do not follow the form host[,ip].
+ */
+static int
+hostspec_is_complex(const char *hosts)
+{
+ char *cp;
+
+ /* wildcard */
+ if (strchr(hosts, '*') != NULL || strchr(hosts, '?') != NULL)
+ return 1;
+ /* single host/ip = ok */
+ if ((cp = strchr(hosts, ',')) == NULL)
+ return 0;
+ /* more than two entries on the line */
+ if (strchr(cp + 1, ',') != NULL)
+ return 1;
+ /* XXX maybe parse cp+1 and ensure it is an IP? */
+ return 0;
+}
+
+/* callback to search for ctx->keys in known_hosts */
+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->key == NULL)
+ return 0;
+ if (l->status != HKF_STATUS_MATCHED) {
+ /* Record if one of the keys appears on a non-matching line */
+ for (i = 0; i < ctx->nkeys; i++) {
+ if (sshkey_equal(l->key, ctx->keys[i])) {
+ ctx->other_name_seen = 1;
+ debug3_f("found %s key under different "
+ "name/addr at %s:%ld",
+ sshkey_ssh_name(ctx->keys[i]),
+ l->path, l->linenum);
+ return 0;
+ }
+ }
+ return 0;
+ }
+ /* Don't proceed if revocation or CA markers are present */
+ /* XXX relax this */
+ if (l->marker != MRK_NONE) {
+ debug3_f("hostkeys file %s:%ld has CA/revocation marker",
+ l->path, l->linenum);
+ ctx->complex_hostspec = 1;
+ return 0;
+ }
+
+ /* If CheckHostIP is enabled, then check for mismatched hostname/addr */
+ if (ctx->ip_str != NULL && strchr(l->hosts, ',') != NULL) {
+ if ((l->match & HKF_MATCH_HOST) == 0) {
+ /* Record if address matched a different hostname. */
+ ctx->other_name_seen = 1;
+ debug3_f("found address %s against different hostname "
+ "at %s:%ld", ctx->ip_str, l->path, l->linenum);
+ return 0;
+ } else if ((l->match & HKF_MATCH_IP) == 0) {
+ /* Record if hostname matched a different address. */
+ ctx->other_name_seen = 1;
+ debug3_f("found hostname %s against different address "
+ "at %s:%ld", ctx->host_str, l->path, l->linenum);
+ }
+ }
+
+ /*
+ * UpdateHostkeys is skipped for wildcard host names and hostnames
+ * that contain more than two entries (ssh never writes these).
+ */
+ if (hostspec_is_complex(l->hosts)) {
+ debug3_f("hostkeys file %s:%ld complex host specification",
+ l->path, l->linenum);
+ ctx->complex_hostspec = 1;
+ 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]))
+ continue;
+ debug3_f("found %s key at %s:%ld",
+ sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum);
+ ctx->keys_match[i] |= l->match;
+ return 0;
+ }
+ /* This line contained a key that not offered by the server */
+ debug3_f("deprecated %s key at %s:%ld", 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_f("recallocarray failed nold = %zu", ctx->nold);
+ ctx->old_keys = tmp;
+ ctx->old_keys[ctx->nold++] = l->key;
+ l->key = NULL;
+
+ return 0;
+}
+
+/* callback to search for ctx->old_keys in known_hosts under other names */
+static int
+hostkeys_check_old(struct hostkey_foreach_line *l, void *_ctx)
+{
+ struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx;
+ size_t i;
+ int hashed;
+
+ /* only care about lines that *don't* match the active host spec */
+ if (l->status == HKF_STATUS_MATCHED || l->key == NULL)
+ return 0;
+
+ hashed = l->match & (HKF_MATCH_HOST_HASHED|HKF_MATCH_IP_HASHED);
+ for (i = 0; i < ctx->nold; i++) {
+ if (!sshkey_equal(l->key, ctx->old_keys[i]))
+ continue;
+ debug3_f("found deprecated %s key at %s:%ld as %s",
+ sshkey_ssh_name(ctx->old_keys[i]), l->path, l->linenum,
+ hashed ? "[HASHED]" : l->hosts);
+ ctx->old_key_seen = 1;
+ break;
+ }
+ return 0;
+}
+
+/*
+ * Check known_hosts files for deprecated keys under other names. Returns 0
+ * on success or -1 on failure. Updates ctx->old_key_seen if deprecated keys
+ * exist under names other than the active hostname/IP.
+ */
+static int
+check_old_keys_othernames(struct hostkeys_update_ctx *ctx)
+{
+ size_t i;
+ int r;
+
+ debug2_f("checking for %zu deprecated keys", ctx->nold);
+ for (i = 0; i < options.num_user_hostfiles; i++) {
+ debug3_f("searching %s for %s / %s",
+ options.user_hostfiles[i], ctx->host_str,
+ ctx->ip_str ? ctx->ip_str : "(none)");
+ if ((r = hostkeys_foreach(options.user_hostfiles[i],
+ hostkeys_check_old, ctx, ctx->host_str, ctx->ip_str,
+ HKF_WANT_PARSE_KEY, 0)) != 0) {
+ if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) {
+ debug_f("hostkeys file %s does not exist",
+ options.user_hostfiles[i]);
+ continue;
+ }
+ error_fr(r, "hostkeys_foreach failed for %s",
+ options.user_hostfiles[i]);
+ return -1;
+ }
+ }
+ 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_verified[i])
+ continue;
+ if ((fp = sshkey_fingerprint(ctx->keys[i],
+ options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
+ fatal_f("sshkey_fingerprint failed");
+ 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_f("sshkey_fingerprint failed");
+ 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 (response != NULL && 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_f("known hosts file %s does not "
+ "exist", options.user_hostfiles[i]);
+ } else {
+ error_f("known hosts file %s "
+ "inaccessible: %s",
+ options.user_hostfiles[i], 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_fr(r, "hostfile_replace_entries failed for %s",
+ options.user_hostfiles[i]);
+ }
+ }
+}
+
+static void
+client_global_hostkeys_prove_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, plaintype;
+ const u_char *sig;
+ const char *rsa_kexalg = NULL;
+ char *alg = NULL;
+ size_t siglen;
+
+ if (ctx->nnew == 0)
+ fatal_f("ctx->nnew == 0"); /* sanity */
+ if (type != SSH2_MSG_REQUEST_SUCCESS) {
+ error("Server failed to confirm ownership of "
+ "private host keys");
+ hostkeys_update_ctx_free(ctx);
+ return;
+ }
+ if (sshkey_type_plain(sshkey_type_from_name(
+ ssh->kex->hostkey_alg)) == KEY_RSA)
+ rsa_kexalg = ssh->kex->hostkey_alg;
+ if ((signdata = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+ /*
+ * 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_match[i] == 0.
+ */
+ for (ndone = i = 0; i < ctx->nkeys; i++) {
+ if (ctx->keys_match[i])
+ continue;
+ plaintype = sshkey_type_plain(ctx->keys[i]->type);
+ /* 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_stringb(signdata,
+ ssh->kex->session_id)) != 0 ||
+ (r = sshkey_puts(ctx->keys[i], signdata)) != 0)
+ fatal_fr(r, "compose signdata");
+ /* Extract and verify signature */
+ if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) {
+ error_fr(r, "parse sig");
+ goto out;
+ }
+ if ((r = sshkey_get_sigtype(sig, siglen, &alg)) != 0) {
+ error_fr(r, "server gave unintelligible signature "
+ "for %s key %zu", sshkey_type(ctx->keys[i]), i);
+ goto out;
+ }
+ /*
+ * Special case for RSA keys: if a RSA hostkey was negotiated,
+ * then use its signature type for verification of RSA hostkey
+ * proofs. Otherwise, accept only RSA-SHA256/512 signatures.
+ */
+ if (plaintype == KEY_RSA && rsa_kexalg == NULL &&
+ match_pattern_list(alg, HOSTKEY_PROOF_RSA_ALGS, 0) != 1) {
+ debug_f("server used untrusted RSA signature algorithm "
+ "%s for key %zu, disregarding", alg, i);
+ free(alg);
+ /* zap the key from the list */
+ sshkey_free(ctx->keys[i]);
+ ctx->keys[i] = NULL;
+ ndone++;
+ continue;
+ }
+ debug3_f("verify %s key %zu using sigalg %s",
+ sshkey_type(ctx->keys[i]), i, alg);
+ free(alg);
+ if ((r = sshkey_verify(ctx->keys[i], sig, siglen,
+ sshbuf_ptr(signdata), sshbuf_len(signdata),
+ plaintype == KEY_RSA ? rsa_kexalg : NULL, 0, NULL)) != 0) {
+ error_fr(r, "server gave bad signature for %s key %zu",
+ sshkey_type(ctx->keys[i]), i);
+ goto out;
+ }
+ /* Key is good. Mark it as 'seen' */
+ ctx->keys_verified[i] = 1;
+ ndone++;
+ }
+ /* Shouldn't happen */
+ if (ndone != ctx->nnew)
+ fatal_f("ndone != ctx->nnew (%zu / %zu)", ndone, ctx->nnew);
+ if ((r = sshpkt_get_end(ssh)) != 0) {
+ error_f("protocol error");
+ goto out;
+ }
+
+ /* Make the edits to known_hosts */
+ update_known_hosts(ctx);
+ out:
+ hostkeys_update_ctx_free(ctx);
+ hostkeys_update_complete = 1;
+ client_repledge();
+}
+
+/*
+ * 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->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, prove_sent = 0;
+ 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;
+ u_int want;
+
+ if (hostkeys_seen)
+ fatal_f("server already sent hostkeys");
+ if (!can_update_hostkeys())
+ return 1;
+ hostkeys_seen = 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_fr(r, "parse key");
+ goto out;
+ }
+ if ((r = sshkey_from_blob(blob, len, &key)) != 0) {
+ do_log2_fr(r, r == SSH_ERR_KEY_TYPE_UNKNOWN ?
+ SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_ERROR,
+ "convert key");
+ continue;
+ }
+ fp = sshkey_fingerprint(key, options.fingerprint_hash,
+ SSH_FP_DEFAULT);
+ debug3_f("received %s key %s", sshkey_type(key), fp);
+ free(fp);
+
+ if (!key_accepted_by_hostkeyalgs(key)) {
+ debug3_f("%s key not permitted by "
+ "HostkeyAlgorithms", sshkey_ssh_name(key));
+ continue;
+ }
+ /* Skip certs */
+ if (sshkey_is_cert(key)) {
+ debug3_f("%s key is a certificate; skipping",
+ sshkey_ssh_name(key));
+ continue;
+ }
+ /* Ensure keys are unique */
+ for (i = 0; i < ctx->nkeys; i++) {
+ if (sshkey_equal(key, ctx->keys[i])) {
+ error_f("received duplicated %s host key",
+ 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_f("recallocarray failed nkeys = %zu",
+ ctx->nkeys);
+ ctx->keys = tmp;
+ ctx->keys[ctx->nkeys++] = key;
+ key = NULL;
+ }
+
+ if (ctx->nkeys == 0) {
+ debug_f("server sent no hostkeys");
+ goto out;
+ }
+
+ if ((ctx->keys_match = calloc(ctx->nkeys,
+ sizeof(*ctx->keys_match))) == NULL ||
+ (ctx->keys_verified = calloc(ctx->nkeys,
+ sizeof(*ctx->keys_verified))) == NULL)
+ fatal_f("calloc failed");
+
+ 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_f("searching %s for %s / %s",
+ 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, 0)) != 0) {
+ if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) {
+ debug_f("hostkeys file %s does not exist",
+ options.user_hostfiles[i]);
+ continue;
+ }
+ error_fr(r, "hostkeys_foreach failed for %s",
+ options.user_hostfiles[i]);
+ goto out;
+ }
+ }
+
+ /* Figure out if we have any new keys to add */
+ ctx->nnew = ctx->nincomplete = 0;
+ want = HKF_MATCH_HOST | ( options.check_host_ip ? HKF_MATCH_IP : 0);
+ for (i = 0; i < ctx->nkeys; i++) {
+ if (ctx->keys_match[i] == 0)
+ ctx->nnew++;
+ if ((ctx->keys_match[i] & want) != want)
+ ctx->nincomplete++;
+ }
+
+ debug3_f("%zu server keys: %zu new, %zu retained, "
+ "%zu incomplete match. %zu to remove", ctx->nkeys, ctx->nnew,
+ ctx->nkeys - ctx->nnew - ctx->nincomplete,
+ ctx->nincomplete, ctx->nold);
+
+ if (ctx->nnew == 0 && ctx->nold == 0) {
+ debug_f("no new or deprecated keys from server");
+ goto out;
+ }
+
+ /* Various reasons why we cannot proceed with the update */
+ if (ctx->complex_hostspec) {
+ debug_f("CA/revocation marker, manual host list or wildcard "
+ "host pattern found, skipping UserKnownHostsFile update");
+ goto out;
+ }
+ if (ctx->other_name_seen) {
+ debug_f("host key found matching a different name/address, "
+ "skipping UserKnownHostsFile update");
+ goto out;
+ }
+ /*
+ * If removing keys, check whether they appear under different
+ * names/addresses and refuse to proceed if they do. This avoids
+ * cases such as hosts with multiple names becoming inconsistent
+ * with regards to CheckHostIP entries.
+ * XXX UpdateHostkeys=force to override this (and other) checks?
+ */
+ if (ctx->nold != 0) {
+ if (check_old_keys_othernames(ctx) != 0)
+ goto out; /* error already logged */
+ if (ctx->old_key_seen) {
+ debug_f("key(s) for %s%s%s exist under other names; "
+ "skipping UserKnownHostsFile update",
+ ctx->host_str, ctx->ip_str == NULL ? "" : ",",
+ ctx->ip_str == NULL ? "" : ctx->ip_str);
+ goto out;
+ }
+ }
+
+ if (ctx->nnew == 0) {
+ /*
+ * We have some keys to remove or fix matching for.
+ * We can proceed to do this without requiring a fresh proof
+ * from the server.
+ */
+ update_known_hosts(ctx);
+ goto out;
+ }
+ /*
+ * We have received previously-unseen keys from the server.
+ * Ask the server to confirm ownership of the private halves.
+ */
+ debug3_f("asking server to prove ownership for %zu keys", 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_fr(r, "prepare hostkeys-prove");
+ if ((buf = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new");
+ for (i = 0; i < ctx->nkeys; i++) {
+ if (ctx->keys_match[i])
+ continue;
+ sshbuf_reset(buf);
+ if ((r = sshkey_putb(ctx->keys[i], buf)) != 0 ||
+ (r = sshpkt_put_stringb(ssh, buf)) != 0)
+ fatal_fr(r, "assemble hostkeys-prove");
+ }
+ if ((r = sshpkt_send(ssh)) != 0)
+ fatal_fr(r, "send hostkeys-prove");
+ client_register_global_confirm(
+ client_global_hostkeys_prove_confirm, ctx);
+ ctx = NULL; /* will be freed in callback */
+ prove_sent = 1;
+
+ /* Success */
+ out:
+ hostkeys_update_ctx_free(ctx);
+ sshkey_free(key);
+ sshbuf_free(buf);
+ if (!prove_sent) {
+ /* UpdateHostkeys handling completed */
+ hostkeys_update_complete = 1;
+ client_repledge();
+ }
+ /*
+ * 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;
+}
+
+static void
+client_send_env(struct ssh *ssh, int id, const char *name, const char *val)
+{
+ int r;
+
+ debug("channel %d: setting env %s = \"%s\"", id, 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_fr(r, "send setenv");
+}
+
+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)
+{
+ size_t i, j, len;
+ int matched, r;
+ char *name, *val;
+ Channel *c = NULL;
+
+ debug2_f("id %d", id);
+
+ if ((c = channel_lookup(ssh, id)) == NULL)
+ fatal_f("channel %d: unknown channel", 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_fr(r, "build pty-req");
+ if (tiop == NULL)
+ tiop = get_saved_tio();
+ ssh_tty_make_modes(ssh, -1, tiop);
+ if ((r = sshpkt_send(ssh)) != 0)
+ fatal_fr(r, "send pty-req");
+ /* 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;
+ }
+ client_send_env(ssh, id, name, val);
+ 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';
+ client_send_env(ssh, id, name, val);
+ free(name);
+ }
+
+ len = sshbuf_len(cmd);
+ if (len > 0) {
+ if (len > 900)
+ len = 900;
+ if (want_subsystem) {
+ debug("Sending subsystem: %.*s",
+ (int)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",
+ (int)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_fr(r, "send command");
+ } else {
+ channel_request_start(ssh, id, "shell", 1);
+ client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE);
+ if ((r = sshpkt_send(ssh)) != 0)
+ fatal_fr(r, "send shell");
+ }
+
+ session_setup_complete = 1;
+ client_repledge();
+}
+
+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 || options.session_type == SESSION_TYPE_NONE) {
+ session_closed = 1;
+ setproctitle("[stopped mux]");
+ }
+}
+
+/* client specific fatal cleanup */
+void
+cleanup_exit(int i)
+{
+ leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
+ if (options.control_path != NULL && muxserver_sock != -1)
+ unlink(options.control_path);
+ ssh_kill_proxy_command();
+ _exit(i);
+}