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diff --git a/sshd.c b/sshd.c
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+/* $OpenBSD: sshd.c,v 1.596 2023/01/18 01:50:21 millert Exp $ */
+/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ * All rights reserved
+ * This program is the ssh daemon. It listens for connections from clients,
+ * and performs authentication, executes use commands or shell, and forwards
+ * information to/from the application to the user client over an encrypted
+ * connection. This can also handle forwarding of X11, TCP/IP, and
+ * authentication agent connections.
+ *
+ * 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".
+ *
+ * SSH2 implementation:
+ * Privilege Separation:
+ *
+ * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved.
+ * Copyright (c) 2002 Niels Provos. 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>
+#include <sys/socket.h>
+#ifdef HAVE_SYS_STAT_H
+# include <sys/stat.h>
+#endif
+#ifdef HAVE_SYS_TIME_H
+# include <sys/time.h>
+#endif
+#include "openbsd-compat/sys-tree.h"
+#include "openbsd-compat/sys-queue.h"
+#include <sys/wait.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <netdb.h>
+#ifdef HAVE_PATHS_H
+#include <paths.h>
+#endif
+#include <grp.h>
+#ifdef HAVE_POLL_H
+#include <poll.h>
+#endif
+#include <pwd.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <limits.h>
+
+#ifdef WITH_OPENSSL
+#include <openssl/dh.h>
+#include <openssl/bn.h>
+#include <openssl/rand.h>
+#include "openbsd-compat/openssl-compat.h"
+#endif
+
+#ifdef HAVE_SECUREWARE
+#include <sys/security.h>
+#include <prot.h>
+#endif
+
+#include "xmalloc.h"
+#include "ssh.h"
+#include "ssh2.h"
+#include "sshpty.h"
+#include "packet.h"
+#include "log.h"
+#include "sshbuf.h"
+#include "misc.h"
+#include "match.h"
+#include "servconf.h"
+#include "uidswap.h"
+#include "compat.h"
+#include "cipher.h"
+#include "digest.h"
+#include "sshkey.h"
+#include "kex.h"
+#include "myproposal.h"
+#include "authfile.h"
+#include "pathnames.h"
+#include "atomicio.h"
+#include "canohost.h"
+#include "hostfile.h"
+#include "auth.h"
+#include "authfd.h"
+#include "msg.h"
+#include "dispatch.h"
+#include "channels.h"
+#include "session.h"
+#include "monitor.h"
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
+#include "monitor_wrap.h"
+#include "ssh-sandbox.h"
+#include "auth-options.h"
+#include "version.h"
+#include "ssherr.h"
+#include "sk-api.h"
+#include "srclimit.h"
+#include "dh.h"
+
+/* Re-exec fds */
+#define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1)
+#define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2)
+#define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3)
+#define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4)
+
+extern char *__progname;
+
+/* Server configuration options. */
+ServerOptions options;
+
+/* Name of the server configuration file. */
+char *config_file_name = _PATH_SERVER_CONFIG_FILE;
+
+/*
+ * Debug mode flag. This can be set on the command line. If debug
+ * mode is enabled, extra debugging output will be sent to the system
+ * log, the daemon will not go to background, and will exit after processing
+ * the first connection.
+ */
+int debug_flag = 0;
+
+/*
+ * Indicating that the daemon should only test the configuration and keys.
+ * If test_flag > 1 ("-T" flag), then sshd will also dump the effective
+ * configuration, optionally using connection information provided by the
+ * "-C" flag.
+ */
+static int test_flag = 0;
+
+/* Flag indicating that the daemon is being started from inetd. */
+static int inetd_flag = 0;
+
+/* Flag indicating that sshd should not detach and become a daemon. */
+static int no_daemon_flag = 0;
+
+/* debug goes to stderr unless inetd_flag is set */
+static int log_stderr = 0;
+
+/* Saved arguments to main(). */
+static char **saved_argv;
+static int saved_argc;
+
+/* re-exec */
+static int rexeced_flag = 0;
+static int rexec_flag = 1;
+static int rexec_argc = 0;
+static char **rexec_argv;
+
+/*
+ * The sockets that the server is listening; this is used in the SIGHUP
+ * signal handler.
+ */
+#define MAX_LISTEN_SOCKS 16
+static int listen_socks[MAX_LISTEN_SOCKS];
+static int num_listen_socks = 0;
+
+/* Daemon's agent connection */
+int auth_sock = -1;
+static int have_agent = 0;
+
+/*
+ * Any really sensitive data in the application is contained in this
+ * structure. The idea is that this structure could be locked into memory so
+ * that the pages do not get written into swap. However, there are some
+ * problems. The private key contains BIGNUMs, and we do not (in principle)
+ * have access to the internals of them, and locking just the structure is
+ * not very useful. Currently, memory locking is not implemented.
+ */
+struct {
+ struct sshkey **host_keys; /* all private host keys */
+ struct sshkey **host_pubkeys; /* all public host keys */
+ struct sshkey **host_certificates; /* all public host certificates */
+ int have_ssh2_key;
+} sensitive_data;
+
+/* This is set to true when a signal is received. */
+static volatile sig_atomic_t received_sighup = 0;
+static volatile sig_atomic_t received_sigterm = 0;
+
+/* record remote hostname or ip */
+u_int utmp_len = HOST_NAME_MAX+1;
+
+/*
+ * startup_pipes/flags are used for tracking children of the listening sshd
+ * process early in their lifespans. This tracking is needed for three things:
+ *
+ * 1) Implementing the MaxStartups limit of concurrent unauthenticated
+ * connections.
+ * 2) Avoiding a race condition for SIGHUP processing, where child processes
+ * may have listen_socks open that could collide with main listener process
+ * after it restarts.
+ * 3) Ensuring that rexec'd sshd processes have received their initial state
+ * from the parent listen process before handling SIGHUP.
+ *
+ * Child processes signal that they have completed closure of the listen_socks
+ * and (if applicable) received their rexec state by sending a char over their
+ * sock. Child processes signal that authentication has completed by closing
+ * the sock (or by exiting).
+ */
+static int *startup_pipes = NULL;
+static int *startup_flags = NULL; /* Indicates child closed listener */
+static int startup_pipe = -1; /* in child */
+
+/* variables used for privilege separation */
+int use_privsep = -1;
+struct monitor *pmonitor = NULL;
+int privsep_is_preauth = 1;
+static int privsep_chroot = 1;
+
+/* global connection state and authentication contexts */
+Authctxt *the_authctxt = NULL;
+struct ssh *the_active_state;
+
+/* global key/cert auth options. XXX move to permanent ssh->authctxt? */
+struct sshauthopt *auth_opts = NULL;
+
+/* sshd_config buffer */
+struct sshbuf *cfg;
+
+/* Included files from the configuration file */
+struct include_list includes = TAILQ_HEAD_INITIALIZER(includes);
+
+/* message to be displayed after login */
+struct sshbuf *loginmsg;
+
+/* Unprivileged user */
+struct passwd *privsep_pw = NULL;
+
+/* Prototypes for various functions defined later in this file. */
+void destroy_sensitive_data(void);
+void demote_sensitive_data(void);
+static void do_ssh2_kex(struct ssh *);
+
+static char *listener_proctitle;
+
+/*
+ * Close all listening sockets
+ */
+static void
+close_listen_socks(void)
+{
+ int i;
+
+ for (i = 0; i < num_listen_socks; i++)
+ close(listen_socks[i]);
+ num_listen_socks = 0;
+}
+
+static void
+close_startup_pipes(void)
+{
+ int i;
+
+ if (startup_pipes)
+ for (i = 0; i < options.max_startups; i++)
+ if (startup_pipes[i] != -1)
+ close(startup_pipes[i]);
+}
+
+/*
+ * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
+ * the effect is to reread the configuration file (and to regenerate
+ * the server key).
+ */
+
+/*ARGSUSED*/
+static void
+sighup_handler(int sig)
+{
+ received_sighup = 1;
+}
+
+/*
+ * Called from the main program after receiving SIGHUP.
+ * Restarts the server.
+ */
+static void
+sighup_restart(void)
+{
+ logit("Received SIGHUP; restarting.");
+ if (options.pid_file != NULL)
+ unlink(options.pid_file);
+ platform_pre_restart();
+ close_listen_socks();
+ close_startup_pipes();
+ ssh_signal(SIGHUP, SIG_IGN); /* will be restored after exec */
+ execv(saved_argv[0], saved_argv);
+ logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0],
+ strerror(errno));
+ exit(1);
+}
+
+/*
+ * Generic signal handler for terminating signals in the master daemon.
+ */
+/*ARGSUSED*/
+static void
+sigterm_handler(int sig)
+{
+ received_sigterm = sig;
+}
+
+/*
+ * SIGCHLD handler. This is called whenever a child dies. This will then
+ * reap any zombies left by exited children.
+ */
+/*ARGSUSED*/
+static void
+main_sigchld_handler(int sig)
+{
+ int save_errno = errno;
+ pid_t pid;
+ int status;
+
+ while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
+ (pid == -1 && errno == EINTR))
+ ;
+ errno = save_errno;
+}
+
+/*
+ * Signal handler for the alarm after the login grace period has expired.
+ */
+/*ARGSUSED*/
+static void
+grace_alarm_handler(int sig)
+{
+ /*
+ * Try to kill any processes that we have spawned, E.g. authorized
+ * keys command helpers or privsep children.
+ */
+ if (getpgid(0) == getpid()) {
+ ssh_signal(SIGTERM, SIG_IGN);
+ kill(0, SIGTERM);
+ }
+
+ /* Log error and exit. */
+ sigdie("Timeout before authentication for %s port %d",
+ ssh_remote_ipaddr(the_active_state),
+ ssh_remote_port(the_active_state));
+}
+
+/* Destroy the host and server keys. They will no longer be needed. */
+void
+destroy_sensitive_data(void)
+{
+ u_int i;
+
+ for (i = 0; i < options.num_host_key_files; i++) {
+ if (sensitive_data.host_keys[i]) {
+ sshkey_free(sensitive_data.host_keys[i]);
+ sensitive_data.host_keys[i] = NULL;
+ }
+ if (sensitive_data.host_certificates[i]) {
+ sshkey_free(sensitive_data.host_certificates[i]);
+ sensitive_data.host_certificates[i] = NULL;
+ }
+ }
+}
+
+/* Demote private to public keys for network child */
+void
+demote_sensitive_data(void)
+{
+ struct sshkey *tmp;
+ u_int i;
+ int r;
+
+ for (i = 0; i < options.num_host_key_files; i++) {
+ if (sensitive_data.host_keys[i]) {
+ if ((r = sshkey_from_private(
+ sensitive_data.host_keys[i], &tmp)) != 0)
+ fatal_r(r, "could not demote host %s key",
+ sshkey_type(sensitive_data.host_keys[i]));
+ sshkey_free(sensitive_data.host_keys[i]);
+ sensitive_data.host_keys[i] = tmp;
+ }
+ /* Certs do not need demotion */
+ }
+}
+
+static void
+reseed_prngs(void)
+{
+ u_int32_t rnd[256];
+
+#ifdef WITH_OPENSSL
+ RAND_poll();
+#endif
+ arc4random_stir(); /* noop on recent arc4random() implementations */
+ arc4random_buf(rnd, sizeof(rnd)); /* let arc4random notice PID change */
+
+#ifdef WITH_OPENSSL
+ RAND_seed(rnd, sizeof(rnd));
+ /* give libcrypto a chance to notice the PID change */
+ if ((RAND_bytes((u_char *)rnd, 1)) != 1)
+ fatal("%s: RAND_bytes failed", __func__);
+#endif
+
+ explicit_bzero(rnd, sizeof(rnd));
+}
+
+static void
+privsep_preauth_child(void)
+{
+ gid_t gidset[1];
+
+ /* Enable challenge-response authentication for privilege separation */
+ privsep_challenge_enable();
+
+#ifdef GSSAPI
+ /* Cache supported mechanism OIDs for later use */
+ ssh_gssapi_prepare_supported_oids();
+#endif
+
+ reseed_prngs();
+
+ /* Demote the private keys to public keys. */
+ demote_sensitive_data();
+
+ /* Demote the child */
+ if (privsep_chroot) {
+ /* Change our root directory */
+ if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1)
+ fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR,
+ strerror(errno));
+ if (chdir("/") == -1)
+ fatal("chdir(\"/\"): %s", strerror(errno));
+
+ /* Drop our privileges */
+ debug3("privsep user:group %u:%u", (u_int)privsep_pw->pw_uid,
+ (u_int)privsep_pw->pw_gid);
+ gidset[0] = privsep_pw->pw_gid;
+ if (setgroups(1, gidset) == -1)
+ fatal("setgroups: %.100s", strerror(errno));
+ permanently_set_uid(privsep_pw);
+ }
+}
+
+static int
+privsep_preauth(struct ssh *ssh)
+{
+ int status, r;
+ pid_t pid;
+ struct ssh_sandbox *box = NULL;
+
+ /* Set up unprivileged child process to deal with network data */
+ pmonitor = monitor_init();
+ /* Store a pointer to the kex for later rekeying */
+ pmonitor->m_pkex = &ssh->kex;
+
+ if (use_privsep == PRIVSEP_ON)
+ box = ssh_sandbox_init(pmonitor);
+ pid = fork();
+ if (pid == -1) {
+ fatal("fork of unprivileged child failed");
+ } else if (pid != 0) {
+ debug2("Network child is on pid %ld", (long)pid);
+
+ pmonitor->m_pid = pid;
+ if (have_agent) {
+ r = ssh_get_authentication_socket(&auth_sock);
+ if (r != 0) {
+ error_r(r, "Could not get agent socket");
+ have_agent = 0;
+ }
+ }
+ if (box != NULL)
+ ssh_sandbox_parent_preauth(box, pid);
+ monitor_child_preauth(ssh, pmonitor);
+
+ /* Wait for the child's exit status */
+ while (waitpid(pid, &status, 0) == -1) {
+ if (errno == EINTR)
+ continue;
+ pmonitor->m_pid = -1;
+ fatal_f("waitpid: %s", strerror(errno));
+ }
+ privsep_is_preauth = 0;
+ pmonitor->m_pid = -1;
+ if (WIFEXITED(status)) {
+ if (WEXITSTATUS(status) != 0)
+ fatal_f("preauth child exited with status %d",
+ WEXITSTATUS(status));
+ } else if (WIFSIGNALED(status))
+ fatal_f("preauth child terminated by signal %d",
+ WTERMSIG(status));
+ if (box != NULL)
+ ssh_sandbox_parent_finish(box);
+ return 1;
+ } else {
+ /* child */
+ close(pmonitor->m_sendfd);
+ close(pmonitor->m_log_recvfd);
+
+ /* Arrange for logging to be sent to the monitor */
+ set_log_handler(mm_log_handler, pmonitor);
+
+ privsep_preauth_child();
+ setproctitle("%s", "[net]");
+ if (box != NULL)
+ ssh_sandbox_child(box);
+
+ return 0;
+ }
+}
+
+static void
+privsep_postauth(struct ssh *ssh, Authctxt *authctxt)
+{
+#ifdef DISABLE_FD_PASSING
+ if (1) {
+#else
+ if (authctxt->pw->pw_uid == 0) {
+#endif
+ /* File descriptor passing is broken or root login */
+ use_privsep = 0;
+ goto skip;
+ }
+
+ /* New socket pair */
+ monitor_reinit(pmonitor);
+
+ pmonitor->m_pid = fork();
+ if (pmonitor->m_pid == -1)
+ fatal("fork of unprivileged child failed");
+ else if (pmonitor->m_pid != 0) {
+ verbose("User child is on pid %ld", (long)pmonitor->m_pid);
+ sshbuf_reset(loginmsg);
+ monitor_clear_keystate(ssh, pmonitor);
+ monitor_child_postauth(ssh, pmonitor);
+
+ /* NEVERREACHED */
+ exit(0);
+ }
+
+ /* child */
+
+ close(pmonitor->m_sendfd);
+ pmonitor->m_sendfd = -1;
+
+ /* Demote the private keys to public keys. */
+ demote_sensitive_data();
+
+ reseed_prngs();
+
+ /* Drop privileges */
+ do_setusercontext(authctxt->pw);
+
+ skip:
+ /* It is safe now to apply the key state */
+ monitor_apply_keystate(ssh, pmonitor);
+
+ /*
+ * Tell the packet layer that authentication was successful, since
+ * this information is not part of the key state.
+ */
+ ssh_packet_set_authenticated(ssh);
+}
+
+static void
+append_hostkey_type(struct sshbuf *b, const char *s)
+{
+ int r;
+
+ if (match_pattern_list(s, options.hostkeyalgorithms, 0) != 1) {
+ debug3_f("%s key not permitted by HostkeyAlgorithms", s);
+ return;
+ }
+ if ((r = sshbuf_putf(b, "%s%s", sshbuf_len(b) > 0 ? "," : "", s)) != 0)
+ fatal_fr(r, "sshbuf_putf");
+}
+
+static char *
+list_hostkey_types(void)
+{
+ struct sshbuf *b;
+ struct sshkey *key;
+ char *ret;
+ u_int i;
+
+ if ((b = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+ for (i = 0; i < options.num_host_key_files; i++) {
+ key = sensitive_data.host_keys[i];
+ if (key == NULL)
+ key = sensitive_data.host_pubkeys[i];
+ if (key == NULL)
+ continue;
+ switch (key->type) {
+ case KEY_RSA:
+ /* for RSA we also support SHA2 signatures */
+ append_hostkey_type(b, "rsa-sha2-512");
+ append_hostkey_type(b, "rsa-sha2-256");
+ /* FALLTHROUGH */
+ case KEY_DSA:
+ case KEY_ECDSA:
+ case KEY_ED25519:
+ case KEY_ECDSA_SK:
+ case KEY_ED25519_SK:
+ case KEY_XMSS:
+ append_hostkey_type(b, sshkey_ssh_name(key));
+ break;
+ }
+ /* If the private key has a cert peer, then list that too */
+ key = sensitive_data.host_certificates[i];
+ if (key == NULL)
+ continue;
+ switch (key->type) {
+ case KEY_RSA_CERT:
+ /* for RSA we also support SHA2 signatures */
+ append_hostkey_type(b,
+ "rsa-sha2-512-cert-v01@openssh.com");
+ append_hostkey_type(b,
+ "rsa-sha2-256-cert-v01@openssh.com");
+ /* FALLTHROUGH */
+ case KEY_DSA_CERT:
+ case KEY_ECDSA_CERT:
+ case KEY_ED25519_CERT:
+ case KEY_ECDSA_SK_CERT:
+ case KEY_ED25519_SK_CERT:
+ case KEY_XMSS_CERT:
+ append_hostkey_type(b, sshkey_ssh_name(key));
+ break;
+ }
+ }
+ if ((ret = sshbuf_dup_string(b)) == NULL)
+ fatal_f("sshbuf_dup_string failed");
+ sshbuf_free(b);
+ debug_f("%s", ret);
+ return ret;
+}
+
+static struct sshkey *
+get_hostkey_by_type(int type, int nid, int need_private, struct ssh *ssh)
+{
+ u_int i;
+ struct sshkey *key;
+
+ for (i = 0; i < options.num_host_key_files; i++) {
+ switch (type) {
+ case KEY_RSA_CERT:
+ case KEY_DSA_CERT:
+ case KEY_ECDSA_CERT:
+ case KEY_ED25519_CERT:
+ case KEY_ECDSA_SK_CERT:
+ case KEY_ED25519_SK_CERT:
+ case KEY_XMSS_CERT:
+ key = sensitive_data.host_certificates[i];
+ break;
+ default:
+ key = sensitive_data.host_keys[i];
+ if (key == NULL && !need_private)
+ key = sensitive_data.host_pubkeys[i];
+ break;
+ }
+ if (key == NULL || key->type != type)
+ continue;
+ switch (type) {
+ case KEY_ECDSA:
+ case KEY_ECDSA_SK:
+ case KEY_ECDSA_CERT:
+ case KEY_ECDSA_SK_CERT:
+ if (key->ecdsa_nid != nid)
+ continue;
+ /* FALLTHROUGH */
+ default:
+ return need_private ?
+ sensitive_data.host_keys[i] : key;
+ }
+ }
+ return NULL;
+}
+
+struct sshkey *
+get_hostkey_public_by_type(int type, int nid, struct ssh *ssh)
+{
+ return get_hostkey_by_type(type, nid, 0, ssh);
+}
+
+struct sshkey *
+get_hostkey_private_by_type(int type, int nid, struct ssh *ssh)
+{
+ return get_hostkey_by_type(type, nid, 1, ssh);
+}
+
+struct sshkey *
+get_hostkey_by_index(int ind)
+{
+ if (ind < 0 || (u_int)ind >= options.num_host_key_files)
+ return (NULL);
+ return (sensitive_data.host_keys[ind]);
+}
+
+struct sshkey *
+get_hostkey_public_by_index(int ind, struct ssh *ssh)
+{
+ if (ind < 0 || (u_int)ind >= options.num_host_key_files)
+ return (NULL);
+ return (sensitive_data.host_pubkeys[ind]);
+}
+
+int
+get_hostkey_index(struct sshkey *key, int compare, struct ssh *ssh)
+{
+ u_int i;
+
+ for (i = 0; i < options.num_host_key_files; i++) {
+ if (sshkey_is_cert(key)) {
+ if (key == sensitive_data.host_certificates[i] ||
+ (compare && sensitive_data.host_certificates[i] &&
+ sshkey_equal(key,
+ sensitive_data.host_certificates[i])))
+ return (i);
+ } else {
+ if (key == sensitive_data.host_keys[i] ||
+ (compare && sensitive_data.host_keys[i] &&
+ sshkey_equal(key, sensitive_data.host_keys[i])))
+ return (i);
+ if (key == sensitive_data.host_pubkeys[i] ||
+ (compare && sensitive_data.host_pubkeys[i] &&
+ sshkey_equal(key, sensitive_data.host_pubkeys[i])))
+ return (i);
+ }
+ }
+ return (-1);
+}
+
+/* Inform the client of all hostkeys */
+static void
+notify_hostkeys(struct ssh *ssh)
+{
+ struct sshbuf *buf;
+ struct sshkey *key;
+ u_int i, nkeys;
+ int r;
+ char *fp;
+
+ /* Some clients cannot cope with the hostkeys message, skip those. */
+ if (ssh->compat & SSH_BUG_HOSTKEYS)
+ return;
+
+ if ((buf = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new");
+ for (i = nkeys = 0; i < options.num_host_key_files; i++) {
+ key = get_hostkey_public_by_index(i, ssh);
+ if (key == NULL || key->type == KEY_UNSPEC ||
+ sshkey_is_cert(key))
+ continue;
+ fp = sshkey_fingerprint(key, options.fingerprint_hash,
+ SSH_FP_DEFAULT);
+ debug3_f("key %d: %s %s", i, sshkey_ssh_name(key), fp);
+ free(fp);
+ if (nkeys == 0) {
+ /*
+ * Start building the request when we find the
+ * first usable key.
+ */
+ if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 ||
+ (r = sshpkt_put_cstring(ssh, "hostkeys-00@openssh.com")) != 0 ||
+ (r = sshpkt_put_u8(ssh, 0)) != 0) /* want reply */
+ sshpkt_fatal(ssh, r, "%s: start request", __func__);
+ }
+ /* Append the key to the request */
+ sshbuf_reset(buf);
+ if ((r = sshkey_putb(key, buf)) != 0)
+ fatal_fr(r, "couldn't put hostkey %d", i);
+ if ((r = sshpkt_put_stringb(ssh, buf)) != 0)
+ sshpkt_fatal(ssh, r, "%s: append key", __func__);
+ nkeys++;
+ }
+ debug3_f("sent %u hostkeys", nkeys);
+ if (nkeys == 0)
+ fatal_f("no hostkeys");
+ if ((r = sshpkt_send(ssh)) != 0)
+ sshpkt_fatal(ssh, r, "%s: send", __func__);
+ sshbuf_free(buf);
+}
+
+/*
+ * returns 1 if connection should be dropped, 0 otherwise.
+ * dropping starts at connection #max_startups_begin with a probability
+ * of (max_startups_rate/100). the probability increases linearly until
+ * all connections are dropped for startups > max_startups
+ */
+static int
+should_drop_connection(int startups)
+{
+ int p, r;
+
+ if (startups < options.max_startups_begin)
+ return 0;
+ if (startups >= options.max_startups)
+ return 1;
+ if (options.max_startups_rate == 100)
+ return 1;
+
+ p = 100 - options.max_startups_rate;
+ p *= startups - options.max_startups_begin;
+ p /= options.max_startups - options.max_startups_begin;
+ p += options.max_startups_rate;
+ r = arc4random_uniform(100);
+
+ debug_f("p %d, r %d", p, r);
+ return (r < p) ? 1 : 0;
+}
+
+/*
+ * Check whether connection should be accepted by MaxStartups.
+ * Returns 0 if the connection is accepted. If the connection is refused,
+ * returns 1 and attempts to send notification to client.
+ * Logs when the MaxStartups condition is entered or exited, and periodically
+ * while in that state.
+ */
+static int
+drop_connection(int sock, int startups, int notify_pipe)
+{
+ char *laddr, *raddr;
+ const char msg[] = "Exceeded MaxStartups\r\n";
+ static time_t last_drop, first_drop;
+ static u_int ndropped;
+ LogLevel drop_level = SYSLOG_LEVEL_VERBOSE;
+ time_t now;
+
+ now = monotime();
+ if (!should_drop_connection(startups) &&
+ srclimit_check_allow(sock, notify_pipe) == 1) {
+ if (last_drop != 0 &&
+ startups < options.max_startups_begin - 1) {
+ /* XXX maybe need better hysteresis here */
+ logit("exited MaxStartups throttling after %s, "
+ "%u connections dropped",
+ fmt_timeframe(now - first_drop), ndropped);
+ last_drop = 0;
+ }
+ return 0;
+ }
+
+#define SSHD_MAXSTARTUPS_LOG_INTERVAL (5 * 60)
+ if (last_drop == 0) {
+ error("beginning MaxStartups throttling");
+ drop_level = SYSLOG_LEVEL_INFO;
+ first_drop = now;
+ ndropped = 0;
+ } else if (last_drop + SSHD_MAXSTARTUPS_LOG_INTERVAL < now) {
+ /* Periodic logs */
+ error("in MaxStartups throttling for %s, "
+ "%u connections dropped",
+ fmt_timeframe(now - first_drop), ndropped + 1);
+ drop_level = SYSLOG_LEVEL_INFO;
+ }
+ last_drop = now;
+ ndropped++;
+
+ laddr = get_local_ipaddr(sock);
+ raddr = get_peer_ipaddr(sock);
+ do_log2(drop_level, "drop connection #%d from [%s]:%d on [%s]:%d "
+ "past MaxStartups", startups, raddr, get_peer_port(sock),
+ laddr, get_local_port(sock));
+ free(laddr);
+ free(raddr);
+ /* best-effort notification to client */
+ (void)write(sock, msg, sizeof(msg) - 1);
+ return 1;
+}
+
+static void
+usage(void)
+{
+ fprintf(stderr, "%s, %s\n", SSH_RELEASE, SSH_OPENSSL_VERSION);
+ fprintf(stderr,
+"usage: sshd [-46DdeiqTtV] [-C connection_spec] [-c host_cert_file]\n"
+" [-E log_file] [-f config_file] [-g login_grace_time]\n"
+" [-h host_key_file] [-o option] [-p port] [-u len]\n"
+ );
+ exit(1);
+}
+
+static void
+send_rexec_state(int fd, struct sshbuf *conf)
+{
+ struct sshbuf *m = NULL, *inc = NULL;
+ struct include_item *item = NULL;
+ int r;
+
+ debug3_f("entering fd = %d config len %zu", fd,
+ sshbuf_len(conf));
+
+ if ((m = sshbuf_new()) == NULL || (inc = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+
+ /* pack includes into a string */
+ TAILQ_FOREACH(item, &includes, entry) {
+ if ((r = sshbuf_put_cstring(inc, item->selector)) != 0 ||
+ (r = sshbuf_put_cstring(inc, item->filename)) != 0 ||
+ (r = sshbuf_put_stringb(inc, item->contents)) != 0)
+ fatal_fr(r, "compose includes");
+ }
+
+ /*
+ * Protocol from reexec master to child:
+ * string configuration
+ * string included_files[] {
+ * string selector
+ * string filename
+ * string contents
+ * }
+ */
+ if ((r = sshbuf_put_stringb(m, conf)) != 0 ||
+ (r = sshbuf_put_stringb(m, inc)) != 0)
+ fatal_fr(r, "compose config");
+ if (ssh_msg_send(fd, 0, m) == -1)
+ error_f("ssh_msg_send failed");
+
+ sshbuf_free(m);
+ sshbuf_free(inc);
+
+ debug3_f("done");
+}
+
+static void
+recv_rexec_state(int fd, struct sshbuf *conf)
+{
+ struct sshbuf *m, *inc;
+ u_char *cp, ver;
+ size_t len;
+ int r;
+ struct include_item *item;
+
+ debug3_f("entering fd = %d", fd);
+
+ if ((m = sshbuf_new()) == NULL || (inc = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+ if (ssh_msg_recv(fd, m) == -1)
+ fatal_f("ssh_msg_recv failed");
+ if ((r = sshbuf_get_u8(m, &ver)) != 0)
+ fatal_fr(r, "parse version");
+ if (ver != 0)
+ fatal_f("rexec version mismatch");
+ if ((r = sshbuf_get_string(m, &cp, &len)) != 0 ||
+ (r = sshbuf_get_stringb(m, inc)) != 0)
+ fatal_fr(r, "parse config");
+
+ if (conf != NULL && (r = sshbuf_put(conf, cp, len)))
+ fatal_fr(r, "sshbuf_put");
+
+ while (sshbuf_len(inc) != 0) {
+ item = xcalloc(1, sizeof(*item));
+ if ((item->contents = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+ if ((r = sshbuf_get_cstring(inc, &item->selector, NULL)) != 0 ||
+ (r = sshbuf_get_cstring(inc, &item->filename, NULL)) != 0 ||
+ (r = sshbuf_get_stringb(inc, item->contents)) != 0)
+ fatal_fr(r, "parse includes");
+ TAILQ_INSERT_TAIL(&includes, item, entry);
+ }
+
+ free(cp);
+ sshbuf_free(m);
+
+ debug3_f("done");
+}
+
+/* Accept a connection from inetd */
+static void
+server_accept_inetd(int *sock_in, int *sock_out)
+{
+ if (rexeced_flag) {
+ close(REEXEC_CONFIG_PASS_FD);
+ *sock_in = *sock_out = dup(STDIN_FILENO);
+ } else {
+ *sock_in = dup(STDIN_FILENO);
+ *sock_out = dup(STDOUT_FILENO);
+ }
+ /*
+ * We intentionally do not close the descriptors 0, 1, and 2
+ * as our code for setting the descriptors won't work if
+ * ttyfd happens to be one of those.
+ */
+ if (stdfd_devnull(1, 1, !log_stderr) == -1)
+ error_f("stdfd_devnull failed");
+ debug("inetd sockets after dupping: %d, %d", *sock_in, *sock_out);
+}
+
+/*
+ * Listen for TCP connections
+ */
+static void
+listen_on_addrs(struct listenaddr *la)
+{
+ int ret, listen_sock;
+ struct addrinfo *ai;
+ char ntop[NI_MAXHOST], strport[NI_MAXSERV];
+
+ for (ai = la->addrs; ai; ai = ai->ai_next) {
+ if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
+ continue;
+ if (num_listen_socks >= MAX_LISTEN_SOCKS)
+ fatal("Too many listen sockets. "
+ "Enlarge MAX_LISTEN_SOCKS");
+ if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen,
+ ntop, sizeof(ntop), strport, sizeof(strport),
+ NI_NUMERICHOST|NI_NUMERICSERV)) != 0) {
+ error("getnameinfo failed: %.100s",
+ ssh_gai_strerror(ret));
+ continue;
+ }
+ /* Create socket for listening. */
+ listen_sock = socket(ai->ai_family, ai->ai_socktype,
+ ai->ai_protocol);
+ if (listen_sock == -1) {
+ /* kernel may not support ipv6 */
+ verbose("socket: %.100s", strerror(errno));
+ continue;
+ }
+ if (set_nonblock(listen_sock) == -1) {
+ close(listen_sock);
+ continue;
+ }
+ if (fcntl(listen_sock, F_SETFD, FD_CLOEXEC) == -1) {
+ verbose("socket: CLOEXEC: %s", strerror(errno));
+ close(listen_sock);
+ continue;
+ }
+ /* Socket options */
+ set_reuseaddr(listen_sock);
+ if (la->rdomain != NULL &&
+ set_rdomain(listen_sock, la->rdomain) == -1) {
+ close(listen_sock);
+ continue;
+ }
+
+ /* Only communicate in IPv6 over AF_INET6 sockets. */
+ if (ai->ai_family == AF_INET6)
+ sock_set_v6only(listen_sock);
+
+ debug("Bind to port %s on %s.", strport, ntop);
+
+ /* Bind the socket to the desired port. */
+ if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) == -1) {
+ error("Bind to port %s on %s failed: %.200s.",
+ strport, ntop, strerror(errno));
+ close(listen_sock);
+ continue;
+ }
+ listen_socks[num_listen_socks] = listen_sock;
+ num_listen_socks++;
+
+ /* Start listening on the port. */
+ if (listen(listen_sock, SSH_LISTEN_BACKLOG) == -1)
+ fatal("listen on [%s]:%s: %.100s",
+ ntop, strport, strerror(errno));
+ logit("Server listening on %s port %s%s%s.",
+ ntop, strport,
+ la->rdomain == NULL ? "" : " rdomain ",
+ la->rdomain == NULL ? "" : la->rdomain);
+ }
+}
+
+static void
+server_listen(void)
+{
+ u_int i;
+
+ /* Initialise per-source limit tracking. */
+ srclimit_init(options.max_startups, options.per_source_max_startups,
+ options.per_source_masklen_ipv4, options.per_source_masklen_ipv6);
+
+ for (i = 0; i < options.num_listen_addrs; i++) {
+ listen_on_addrs(&options.listen_addrs[i]);
+ freeaddrinfo(options.listen_addrs[i].addrs);
+ free(options.listen_addrs[i].rdomain);
+ memset(&options.listen_addrs[i], 0,
+ sizeof(options.listen_addrs[i]));
+ }
+ free(options.listen_addrs);
+ options.listen_addrs = NULL;
+ options.num_listen_addrs = 0;
+
+ if (!num_listen_socks)
+ fatal("Cannot bind any address.");
+}
+
+/*
+ * The main TCP accept loop. Note that, for the non-debug case, returns
+ * from this function are in a forked subprocess.
+ */
+static void
+server_accept_loop(int *sock_in, int *sock_out, int *newsock, int *config_s)
+{
+ struct pollfd *pfd = NULL;
+ int i, j, ret, npfd;
+ int ostartups = -1, startups = 0, listening = 0, lameduck = 0;
+ int startup_p[2] = { -1 , -1 }, *startup_pollfd;
+ char c = 0;
+ struct sockaddr_storage from;
+ socklen_t fromlen;
+ pid_t pid;
+ u_char rnd[256];
+ sigset_t nsigset, osigset;
+
+ /* pipes connected to unauthenticated child sshd processes */
+ startup_pipes = xcalloc(options.max_startups, sizeof(int));
+ startup_flags = xcalloc(options.max_startups, sizeof(int));
+ startup_pollfd = xcalloc(options.max_startups, sizeof(int));
+ for (i = 0; i < options.max_startups; i++)
+ startup_pipes[i] = -1;
+
+ /*
+ * Prepare signal mask that we use to block signals that might set
+ * received_sigterm or received_sighup, so that we are guaranteed
+ * to immediately wake up the ppoll if a signal is received after
+ * the flag is checked.
+ */
+ sigemptyset(&nsigset);
+ sigaddset(&nsigset, SIGHUP);
+ sigaddset(&nsigset, SIGCHLD);
+ sigaddset(&nsigset, SIGTERM);
+ sigaddset(&nsigset, SIGQUIT);
+
+ /* sized for worst-case */
+ pfd = xcalloc(num_listen_socks + options.max_startups,
+ sizeof(struct pollfd));
+
+ /*
+ * Stay listening for connections until the system crashes or
+ * the daemon is killed with a signal.
+ */
+ for (;;) {
+ sigprocmask(SIG_BLOCK, &nsigset, &osigset);
+ if (received_sigterm) {
+ logit("Received signal %d; terminating.",
+ (int) received_sigterm);
+ close_listen_socks();
+ if (options.pid_file != NULL)
+ unlink(options.pid_file);
+ exit(received_sigterm == SIGTERM ? 0 : 255);
+ }
+ if (ostartups != startups) {
+ setproctitle("%s [listener] %d of %d-%d startups",
+ listener_proctitle, startups,
+ options.max_startups_begin, options.max_startups);
+ ostartups = startups;
+ }
+ if (received_sighup) {
+ if (!lameduck) {
+ debug("Received SIGHUP; waiting for children");
+ close_listen_socks();
+ lameduck = 1;
+ }
+ if (listening <= 0) {
+ sigprocmask(SIG_SETMASK, &osigset, NULL);
+ sighup_restart();
+ }
+ }
+
+ for (i = 0; i < num_listen_socks; i++) {
+ pfd[i].fd = listen_socks[i];
+ pfd[i].events = POLLIN;
+ }
+ npfd = num_listen_socks;
+ for (i = 0; i < options.max_startups; i++) {
+ startup_pollfd[i] = -1;
+ if (startup_pipes[i] != -1) {
+ pfd[npfd].fd = startup_pipes[i];
+ pfd[npfd].events = POLLIN;
+ startup_pollfd[i] = npfd++;
+ }
+ }
+
+ /* Wait until a connection arrives or a child exits. */
+ ret = ppoll(pfd, npfd, NULL, &osigset);
+ if (ret == -1 && errno != EINTR) {
+ error("ppoll: %.100s", strerror(errno));
+ if (errno == EINVAL)
+ cleanup_exit(1); /* can't recover */
+ }
+ sigprocmask(SIG_SETMASK, &osigset, NULL);
+ if (ret == -1)
+ continue;
+
+ for (i = 0; i < options.max_startups; i++) {
+ if (startup_pipes[i] == -1 ||
+ startup_pollfd[i] == -1 ||
+ !(pfd[startup_pollfd[i]].revents & (POLLIN|POLLHUP)))
+ continue;
+ switch (read(startup_pipes[i], &c, sizeof(c))) {
+ case -1:
+ if (errno == EINTR || errno == EAGAIN)
+ continue;
+ if (errno != EPIPE) {
+ error_f("startup pipe %d (fd=%d): "
+ "read %s", i, startup_pipes[i],
+ strerror(errno));
+ }
+ /* FALLTHROUGH */
+ case 0:
+ /* child exited or completed auth */
+ close(startup_pipes[i]);
+ srclimit_done(startup_pipes[i]);
+ startup_pipes[i] = -1;
+ startups--;
+ if (startup_flags[i])
+ listening--;
+ break;
+ case 1:
+ /* child has finished preliminaries */
+ if (startup_flags[i]) {
+ listening--;
+ startup_flags[i] = 0;
+ }
+ break;
+ }
+ }
+ for (i = 0; i < num_listen_socks; i++) {
+ if (!(pfd[i].revents & POLLIN))
+ continue;
+ fromlen = sizeof(from);
+ *newsock = accept(listen_socks[i],
+ (struct sockaddr *)&from, &fromlen);
+ if (*newsock == -1) {
+ if (errno != EINTR && errno != EWOULDBLOCK &&
+ errno != ECONNABORTED && errno != EAGAIN)
+ error("accept: %.100s",
+ strerror(errno));
+ if (errno == EMFILE || errno == ENFILE)
+ usleep(100 * 1000);
+ continue;
+ }
+ if (unset_nonblock(*newsock) == -1) {
+ close(*newsock);
+ continue;
+ }
+ if (pipe(startup_p) == -1) {
+ error_f("pipe(startup_p): %s", strerror(errno));
+ close(*newsock);
+ continue;
+ }
+ if (drop_connection(*newsock, startups, startup_p[0])) {
+ close(*newsock);
+ close(startup_p[0]);
+ close(startup_p[1]);
+ continue;
+ }
+
+ if (rexec_flag && socketpair(AF_UNIX,
+ SOCK_STREAM, 0, config_s) == -1) {
+ error("reexec socketpair: %s",
+ strerror(errno));
+ close(*newsock);
+ close(startup_p[0]);
+ close(startup_p[1]);
+ continue;
+ }
+
+ for (j = 0; j < options.max_startups; j++)
+ if (startup_pipes[j] == -1) {
+ startup_pipes[j] = startup_p[0];
+ startups++;
+ startup_flags[j] = 1;
+ break;
+ }
+
+ /*
+ * Got connection. Fork a child to handle it, unless
+ * we are in debugging mode.
+ */
+ if (debug_flag) {
+ /*
+ * In debugging mode. Close the listening
+ * socket, and start processing the
+ * connection without forking.
+ */
+ debug("Server will not fork when running in debugging mode.");
+ close_listen_socks();
+ *sock_in = *newsock;
+ *sock_out = *newsock;
+ close(startup_p[0]);
+ close(startup_p[1]);
+ startup_pipe = -1;
+ pid = getpid();
+ if (rexec_flag) {
+ send_rexec_state(config_s[0], cfg);
+ close(config_s[0]);
+ }
+ free(pfd);
+ return;
+ }
+
+ /*
+ * Normal production daemon. Fork, and have
+ * the child process the connection. The
+ * parent continues listening.
+ */
+ platform_pre_fork();
+ listening++;
+ if ((pid = fork()) == 0) {
+ /*
+ * Child. Close the listening and
+ * max_startup sockets. Start using
+ * the accepted socket. Reinitialize
+ * logging (since our pid has changed).
+ * We return from this function to handle
+ * the connection.
+ */
+ platform_post_fork_child();
+ startup_pipe = startup_p[1];
+ close_startup_pipes();
+ close_listen_socks();
+ *sock_in = *newsock;
+ *sock_out = *newsock;
+ log_init(__progname,
+ options.log_level,
+ options.log_facility,
+ log_stderr);
+ if (rexec_flag)
+ close(config_s[0]);
+ else {
+ /*
+ * Signal parent that the preliminaries
+ * for this child are complete. For the
+ * re-exec case, this happens after the
+ * child has received the rexec state
+ * from the server.
+ */
+ (void)atomicio(vwrite, startup_pipe,
+ "\0", 1);
+ }
+ free(pfd);
+ return;
+ }
+
+ /* Parent. Stay in the loop. */
+ platform_post_fork_parent(pid);
+ if (pid == -1)
+ error("fork: %.100s", strerror(errno));
+ else
+ debug("Forked child %ld.", (long)pid);
+
+ close(startup_p[1]);
+
+ if (rexec_flag) {
+ close(config_s[1]);
+ send_rexec_state(config_s[0], cfg);
+ close(config_s[0]);
+ }
+ close(*newsock);
+
+ /*
+ * Ensure that our random state differs
+ * from that of the child
+ */
+ arc4random_stir();
+ arc4random_buf(rnd, sizeof(rnd));
+#ifdef WITH_OPENSSL
+ RAND_seed(rnd, sizeof(rnd));
+ if ((RAND_bytes((u_char *)rnd, 1)) != 1)
+ fatal("%s: RAND_bytes failed", __func__);
+#endif
+ explicit_bzero(rnd, sizeof(rnd));
+ }
+ }
+}
+
+/*
+ * If IP options are supported, make sure there are none (log and
+ * return an error if any are found). Basically we are worried about
+ * source routing; it can be used to pretend you are somebody
+ * (ip-address) you are not. That itself may be "almost acceptable"
+ * under certain circumstances, but rhosts authentication is useless
+ * if source routing is accepted. Notice also that if we just dropped
+ * source routing here, the other side could use IP spoofing to do
+ * rest of the interaction and could still bypass security. So we
+ * exit here if we detect any IP options.
+ */
+static void
+check_ip_options(struct ssh *ssh)
+{
+#ifdef IP_OPTIONS
+ int sock_in = ssh_packet_get_connection_in(ssh);
+ struct sockaddr_storage from;
+ u_char opts[200];
+ socklen_t i, option_size = sizeof(opts), fromlen = sizeof(from);
+ char text[sizeof(opts) * 3 + 1];
+
+ memset(&from, 0, sizeof(from));
+ if (getpeername(sock_in, (struct sockaddr *)&from,
+ &fromlen) == -1)
+ return;
+ if (from.ss_family != AF_INET)
+ return;
+ /* XXX IPv6 options? */
+
+ if (getsockopt(sock_in, IPPROTO_IP, IP_OPTIONS, opts,
+ &option_size) >= 0 && option_size != 0) {
+ text[0] = '\0';
+ for (i = 0; i < option_size; i++)
+ snprintf(text + i*3, sizeof(text) - i*3,
+ " %2.2x", opts[i]);
+ fatal("Connection from %.100s port %d with IP opts: %.800s",
+ ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), text);
+ }
+ return;
+#endif /* IP_OPTIONS */
+}
+
+/* Set the routing domain for this process */
+static void
+set_process_rdomain(struct ssh *ssh, const char *name)
+{
+#if defined(HAVE_SYS_SET_PROCESS_RDOMAIN)
+ if (name == NULL)
+ return; /* default */
+
+ if (strcmp(name, "%D") == 0) {
+ /* "expands" to routing domain of connection */
+ if ((name = ssh_packet_rdomain_in(ssh)) == NULL)
+ return;
+ }
+ /* NB. We don't pass 'ssh' to sys_set_process_rdomain() */
+ return sys_set_process_rdomain(name);
+#elif defined(__OpenBSD__)
+ int rtable, ortable = getrtable();
+ const char *errstr;
+
+ if (name == NULL)
+ return; /* default */
+
+ if (strcmp(name, "%D") == 0) {
+ /* "expands" to routing domain of connection */
+ if ((name = ssh_packet_rdomain_in(ssh)) == NULL)
+ return;
+ }
+
+ rtable = (int)strtonum(name, 0, 255, &errstr);
+ if (errstr != NULL) /* Shouldn't happen */
+ fatal("Invalid routing domain \"%s\": %s", name, errstr);
+ if (rtable != ortable && setrtable(rtable) != 0)
+ fatal("Unable to set routing domain %d: %s",
+ rtable, strerror(errno));
+ debug_f("set routing domain %d (was %d)", rtable, ortable);
+#else /* defined(__OpenBSD__) */
+ fatal("Unable to set routing domain: not supported in this platform");
+#endif
+}
+
+static void
+accumulate_host_timing_secret(struct sshbuf *server_cfg,
+ struct sshkey *key)
+{
+ static struct ssh_digest_ctx *ctx;
+ u_char *hash;
+ size_t len;
+ struct sshbuf *buf;
+ int r;
+
+ if (ctx == NULL && (ctx = ssh_digest_start(SSH_DIGEST_SHA512)) == NULL)
+ fatal_f("ssh_digest_start");
+ if (key == NULL) { /* finalize */
+ /* add server config in case we are using agent for host keys */
+ if (ssh_digest_update(ctx, sshbuf_ptr(server_cfg),
+ sshbuf_len(server_cfg)) != 0)
+ fatal_f("ssh_digest_update");
+ len = ssh_digest_bytes(SSH_DIGEST_SHA512);
+ hash = xmalloc(len);
+ if (ssh_digest_final(ctx, hash, len) != 0)
+ fatal_f("ssh_digest_final");
+ options.timing_secret = PEEK_U64(hash);
+ freezero(hash, len);
+ ssh_digest_free(ctx);
+ ctx = NULL;
+ return;
+ }
+ if ((buf = sshbuf_new()) == NULL)
+ fatal_f("could not allocate buffer");
+ if ((r = sshkey_private_serialize(key, buf)) != 0)
+ fatal_fr(r, "encode %s key", sshkey_ssh_name(key));
+ if (ssh_digest_update(ctx, sshbuf_ptr(buf), sshbuf_len(buf)) != 0)
+ fatal_f("ssh_digest_update");
+ sshbuf_reset(buf);
+ sshbuf_free(buf);
+}
+
+static char *
+prepare_proctitle(int ac, char **av)
+{
+ char *ret = NULL;
+ int i;
+
+ for (i = 0; i < ac; i++)
+ xextendf(&ret, " ", "%s", av[i]);
+ return ret;
+}
+
+/*
+ * Main program for the daemon.
+ */
+int
+main(int ac, char **av)
+{
+ struct ssh *ssh = NULL;
+ extern char *optarg;
+ extern int optind;
+ int r, opt, on = 1, already_daemon, remote_port;
+ int sock_in = -1, sock_out = -1, newsock = -1;
+ const char *remote_ip, *rdomain;
+ char *fp, *line, *laddr, *logfile = NULL;
+ int config_s[2] = { -1 , -1 };
+ u_int i, j;
+ u_int64_t ibytes, obytes;
+ mode_t new_umask;
+ struct sshkey *key;
+ struct sshkey *pubkey;
+ int keytype;
+ Authctxt *authctxt;
+ struct connection_info *connection_info = NULL;
+ sigset_t sigmask;
+
+#ifdef HAVE_SECUREWARE
+ (void)set_auth_parameters(ac, av);
+#endif
+ __progname = ssh_get_progname(av[0]);
+
+ sigemptyset(&sigmask);
+ sigprocmask(SIG_SETMASK, &sigmask, NULL);
+
+ /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
+ saved_argc = ac;
+ rexec_argc = ac;
+ saved_argv = xcalloc(ac + 1, sizeof(*saved_argv));
+ for (i = 0; (int)i < ac; i++)
+ saved_argv[i] = xstrdup(av[i]);
+ saved_argv[i] = NULL;
+
+#ifndef HAVE_SETPROCTITLE
+ /* Prepare for later setproctitle emulation */
+ compat_init_setproctitle(ac, av);
+ av = saved_argv;
+#endif
+
+ if (geteuid() == 0 && setgroups(0, NULL) == -1)
+ debug("setgroups(): %.200s", strerror(errno));
+
+ /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
+ sanitise_stdfd();
+
+ /* Initialize configuration options to their default values. */
+ initialize_server_options(&options);
+
+ /* Parse command-line arguments. */
+ while ((opt = getopt(ac, av,
+ "C:E:b:c:f:g:h:k:o:p:u:46DQRTdeiqrtV")) != -1) {
+ switch (opt) {
+ case '4':
+ options.address_family = AF_INET;
+ break;
+ case '6':
+ options.address_family = AF_INET6;
+ break;
+ case 'f':
+ config_file_name = optarg;
+ break;
+ case 'c':
+ servconf_add_hostcert("[command-line]", 0,
+ &options, optarg);
+ break;
+ case 'd':
+ if (debug_flag == 0) {
+ debug_flag = 1;
+ options.log_level = SYSLOG_LEVEL_DEBUG1;
+ } else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
+ options.log_level++;
+ break;
+ case 'D':
+ no_daemon_flag = 1;
+ break;
+ case 'E':
+ logfile = optarg;
+ /* FALLTHROUGH */
+ case 'e':
+ log_stderr = 1;
+ break;
+ case 'i':
+ inetd_flag = 1;
+ break;
+ case 'r':
+ rexec_flag = 0;
+ break;
+ case 'R':
+ rexeced_flag = 1;
+ inetd_flag = 1;
+ break;
+ case 'Q':
+ /* ignored */
+ break;
+ case 'q':
+ options.log_level = SYSLOG_LEVEL_QUIET;
+ break;
+ case 'b':
+ /* protocol 1, ignored */
+ break;
+ case 'p':
+ options.ports_from_cmdline = 1;
+ if (options.num_ports >= MAX_PORTS) {
+ fprintf(stderr, "too many ports.\n");
+ exit(1);
+ }
+ options.ports[options.num_ports++] = a2port(optarg);
+ if (options.ports[options.num_ports-1] <= 0) {
+ fprintf(stderr, "Bad port number.\n");
+ exit(1);
+ }
+ break;
+ case 'g':
+ if ((options.login_grace_time = convtime(optarg)) == -1) {
+ fprintf(stderr, "Invalid login grace time.\n");
+ exit(1);
+ }
+ break;
+ case 'k':
+ /* protocol 1, ignored */
+ break;
+ case 'h':
+ servconf_add_hostkey("[command-line]", 0,
+ &options, optarg, 1);
+ break;
+ case 't':
+ test_flag = 1;
+ break;
+ case 'T':
+ test_flag = 2;
+ break;
+ case 'C':
+ connection_info = get_connection_info(ssh, 0, 0);
+ if (parse_server_match_testspec(connection_info,
+ optarg) == -1)
+ exit(1);
+ break;
+ case 'u':
+ utmp_len = (u_int)strtonum(optarg, 0, HOST_NAME_MAX+1+1, NULL);
+ if (utmp_len > HOST_NAME_MAX+1) {
+ fprintf(stderr, "Invalid utmp length.\n");
+ exit(1);
+ }
+ break;
+ case 'o':
+ line = xstrdup(optarg);
+ if (process_server_config_line(&options, line,
+ "command-line", 0, NULL, NULL, &includes) != 0)
+ exit(1);
+ free(line);
+ break;
+ case 'V':
+ fprintf(stderr, "%s, %s\n",
+ SSH_VERSION, SSH_OPENSSL_VERSION);
+ exit(0);
+ default:
+ usage();
+ break;
+ }
+ }
+ if (rexeced_flag || inetd_flag)
+ rexec_flag = 0;
+ if (!test_flag && rexec_flag && !path_absolute(av[0]))
+ fatal("sshd re-exec requires execution with an absolute path");
+ if (rexeced_flag)
+ closefrom(REEXEC_MIN_FREE_FD);
+ else
+ closefrom(REEXEC_DEVCRYPTO_RESERVED_FD);
+
+ seed_rng();
+
+ /* If requested, redirect the logs to the specified logfile. */
+ if (logfile != NULL)
+ log_redirect_stderr_to(logfile);
+ /*
+ * Force logging to stderr until we have loaded the private host
+ * key (unless started from inetd)
+ */
+ log_init(__progname,
+ options.log_level == SYSLOG_LEVEL_NOT_SET ?
+ SYSLOG_LEVEL_INFO : options.log_level,
+ options.log_facility == SYSLOG_FACILITY_NOT_SET ?
+ SYSLOG_FACILITY_AUTH : options.log_facility,
+ log_stderr || !inetd_flag || debug_flag);
+
+ /*
+ * Unset KRB5CCNAME, otherwise the user's session may inherit it from
+ * root's environment
+ */
+ if (getenv("KRB5CCNAME") != NULL)
+ (void) unsetenv("KRB5CCNAME");
+
+ sensitive_data.have_ssh2_key = 0;
+
+ /*
+ * If we're not doing an extended test do not silently ignore connection
+ * test params.
+ */
+ if (test_flag < 2 && connection_info != NULL)
+ fatal("Config test connection parameter (-C) provided without "
+ "test mode (-T)");
+
+ /* Fetch our configuration */
+ if ((cfg = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+ if (rexeced_flag) {
+ setproctitle("%s", "[rexeced]");
+ recv_rexec_state(REEXEC_CONFIG_PASS_FD, cfg);
+ if (!debug_flag) {
+ startup_pipe = dup(REEXEC_STARTUP_PIPE_FD);
+ close(REEXEC_STARTUP_PIPE_FD);
+ /*
+ * Signal parent that this child is at a point where
+ * they can go away if they have a SIGHUP pending.
+ */
+ (void)atomicio(vwrite, startup_pipe, "\0", 1);
+ }
+ } else if (strcasecmp(config_file_name, "none") != 0)
+ load_server_config(config_file_name, cfg);
+
+ parse_server_config(&options, rexeced_flag ? "rexec" : config_file_name,
+ cfg, &includes, NULL, rexeced_flag);
+
+#ifdef WITH_OPENSSL
+ if (options.moduli_file != NULL)
+ dh_set_moduli_file(options.moduli_file);
+#endif
+
+ /* Fill in default values for those options not explicitly set. */
+ fill_default_server_options(&options);
+
+ /* Check that options are sensible */
+ if (options.authorized_keys_command_user == NULL &&
+ (options.authorized_keys_command != NULL &&
+ strcasecmp(options.authorized_keys_command, "none") != 0))
+ fatal("AuthorizedKeysCommand set without "
+ "AuthorizedKeysCommandUser");
+ if (options.authorized_principals_command_user == NULL &&
+ (options.authorized_principals_command != NULL &&
+ strcasecmp(options.authorized_principals_command, "none") != 0))
+ fatal("AuthorizedPrincipalsCommand set without "
+ "AuthorizedPrincipalsCommandUser");
+
+ /*
+ * Check whether there is any path through configured auth methods.
+ * Unfortunately it is not possible to verify this generally before
+ * daemonisation in the presence of Match block, but this catches
+ * and warns for trivial misconfigurations that could break login.
+ */
+ if (options.num_auth_methods != 0) {
+ for (i = 0; i < options.num_auth_methods; i++) {
+ if (auth2_methods_valid(options.auth_methods[i],
+ 1) == 0)
+ break;
+ }
+ if (i >= options.num_auth_methods)
+ fatal("AuthenticationMethods cannot be satisfied by "
+ "enabled authentication methods");
+ }
+
+ /* Check that there are no remaining arguments. */
+ if (optind < ac) {
+ fprintf(stderr, "Extra argument %s.\n", av[optind]);
+ exit(1);
+ }
+
+ debug("sshd version %s, %s", SSH_VERSION, SSH_OPENSSL_VERSION);
+
+ /* Store privilege separation user for later use if required. */
+ privsep_chroot = use_privsep && (getuid() == 0 || geteuid() == 0);
+ if ((privsep_pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) {
+ if (privsep_chroot || options.kerberos_authentication)
+ fatal("Privilege separation user %s does not exist",
+ SSH_PRIVSEP_USER);
+ } else {
+ privsep_pw = pwcopy(privsep_pw);
+ freezero(privsep_pw->pw_passwd, strlen(privsep_pw->pw_passwd));
+ privsep_pw->pw_passwd = xstrdup("*");
+ }
+ endpwent();
+
+ /* load host keys */
+ sensitive_data.host_keys = xcalloc(options.num_host_key_files,
+ sizeof(struct sshkey *));
+ sensitive_data.host_pubkeys = xcalloc(options.num_host_key_files,
+ sizeof(struct sshkey *));
+
+ if (options.host_key_agent) {
+ if (strcmp(options.host_key_agent, SSH_AUTHSOCKET_ENV_NAME))
+ setenv(SSH_AUTHSOCKET_ENV_NAME,
+ options.host_key_agent, 1);
+ if ((r = ssh_get_authentication_socket(NULL)) == 0)
+ have_agent = 1;
+ else
+ error_r(r, "Could not connect to agent \"%s\"",
+ options.host_key_agent);
+ }
+
+ for (i = 0; i < options.num_host_key_files; i++) {
+ int ll = options.host_key_file_userprovided[i] ?
+ SYSLOG_LEVEL_ERROR : SYSLOG_LEVEL_DEBUG1;
+
+ if (options.host_key_files[i] == NULL)
+ continue;
+ if ((r = sshkey_load_private(options.host_key_files[i], "",
+ &key, NULL)) != 0 && r != SSH_ERR_SYSTEM_ERROR)
+ do_log2_r(r, ll, "Unable to load host key \"%s\"",
+ options.host_key_files[i]);
+ if (sshkey_is_sk(key) &&
+ key->sk_flags & SSH_SK_USER_PRESENCE_REQD) {
+ debug("host key %s requires user presence, ignoring",
+ options.host_key_files[i]);
+ key->sk_flags &= ~SSH_SK_USER_PRESENCE_REQD;
+ }
+ if (r == 0 && key != NULL &&
+ (r = sshkey_shield_private(key)) != 0) {
+ do_log2_r(r, ll, "Unable to shield host key \"%s\"",
+ options.host_key_files[i]);
+ sshkey_free(key);
+ key = NULL;
+ }
+ if ((r = sshkey_load_public(options.host_key_files[i],
+ &pubkey, NULL)) != 0 && r != SSH_ERR_SYSTEM_ERROR)
+ do_log2_r(r, ll, "Unable to load host key \"%s\"",
+ options.host_key_files[i]);
+ if (pubkey != NULL && key != NULL) {
+ if (!sshkey_equal(pubkey, key)) {
+ error("Public key for %s does not match "
+ "private key", options.host_key_files[i]);
+ sshkey_free(pubkey);
+ pubkey = NULL;
+ }
+ }
+ if (pubkey == NULL && key != NULL) {
+ if ((r = sshkey_from_private(key, &pubkey)) != 0)
+ fatal_r(r, "Could not demote key: \"%s\"",
+ options.host_key_files[i]);
+ }
+ if (pubkey != NULL && (r = sshkey_check_rsa_length(pubkey,
+ options.required_rsa_size)) != 0) {
+ error_fr(r, "Host key %s", options.host_key_files[i]);
+ sshkey_free(pubkey);
+ sshkey_free(key);
+ continue;
+ }
+ sensitive_data.host_keys[i] = key;
+ sensitive_data.host_pubkeys[i] = pubkey;
+
+ if (key == NULL && pubkey != NULL && have_agent) {
+ debug("will rely on agent for hostkey %s",
+ options.host_key_files[i]);
+ keytype = pubkey->type;
+ } else if (key != NULL) {
+ keytype = key->type;
+ accumulate_host_timing_secret(cfg, key);
+ } else {
+ do_log2(ll, "Unable to load host key: %s",
+ options.host_key_files[i]);
+ sensitive_data.host_keys[i] = NULL;
+ sensitive_data.host_pubkeys[i] = NULL;
+ continue;
+ }
+
+ switch (keytype) {
+ case KEY_RSA:
+ case KEY_DSA:
+ case KEY_ECDSA:
+ case KEY_ED25519:
+ case KEY_ECDSA_SK:
+ case KEY_ED25519_SK:
+ case KEY_XMSS:
+ if (have_agent || key != NULL)
+ sensitive_data.have_ssh2_key = 1;
+ break;
+ }
+ if ((fp = sshkey_fingerprint(pubkey, options.fingerprint_hash,
+ SSH_FP_DEFAULT)) == NULL)
+ fatal("sshkey_fingerprint failed");
+ debug("%s host key #%d: %s %s",
+ key ? "private" : "agent", i, sshkey_ssh_name(pubkey), fp);
+ free(fp);
+ }
+ accumulate_host_timing_secret(cfg, NULL);
+ if (!sensitive_data.have_ssh2_key) {
+ logit("sshd: no hostkeys available -- exiting.");
+ exit(1);
+ }
+
+ /*
+ * Load certificates. They are stored in an array at identical
+ * indices to the public keys that they relate to.
+ */
+ sensitive_data.host_certificates = xcalloc(options.num_host_key_files,
+ sizeof(struct sshkey *));
+ for (i = 0; i < options.num_host_key_files; i++)
+ sensitive_data.host_certificates[i] = NULL;
+
+ for (i = 0; i < options.num_host_cert_files; i++) {
+ if (options.host_cert_files[i] == NULL)
+ continue;
+ if ((r = sshkey_load_public(options.host_cert_files[i],
+ &key, NULL)) != 0) {
+ error_r(r, "Could not load host certificate \"%s\"",
+ options.host_cert_files[i]);
+ continue;
+ }
+ if (!sshkey_is_cert(key)) {
+ error("Certificate file is not a certificate: %s",
+ options.host_cert_files[i]);
+ sshkey_free(key);
+ continue;
+ }
+ /* Find matching private key */
+ for (j = 0; j < options.num_host_key_files; j++) {
+ if (sshkey_equal_public(key,
+ sensitive_data.host_pubkeys[j])) {
+ sensitive_data.host_certificates[j] = key;
+ break;
+ }
+ }
+ if (j >= options.num_host_key_files) {
+ error("No matching private key for certificate: %s",
+ options.host_cert_files[i]);
+ sshkey_free(key);
+ continue;
+ }
+ sensitive_data.host_certificates[j] = key;
+ debug("host certificate: #%u type %d %s", j, key->type,
+ sshkey_type(key));
+ }
+
+ if (privsep_chroot) {
+ struct stat st;
+
+ if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) ||
+ (S_ISDIR(st.st_mode) == 0))
+ fatal("Missing privilege separation directory: %s",
+ _PATH_PRIVSEP_CHROOT_DIR);
+
+#ifdef HAVE_CYGWIN
+ if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) &&
+ (st.st_uid != getuid () ||
+ (st.st_mode & (S_IWGRP|S_IWOTH)) != 0))
+#else
+ if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)
+#endif
+ fatal("%s must be owned by root and not group or "
+ "world-writable.", _PATH_PRIVSEP_CHROOT_DIR);
+ }
+
+ if (test_flag > 1) {
+ /*
+ * If no connection info was provided by -C then use
+ * use a blank one that will cause no predicate to match.
+ */
+ if (connection_info == NULL)
+ connection_info = get_connection_info(ssh, 0, 0);
+ connection_info->test = 1;
+ parse_server_match_config(&options, &includes, connection_info);
+ dump_config(&options);
+ }
+
+ /* Configuration looks good, so exit if in test mode. */
+ if (test_flag)
+ exit(0);
+
+ /*
+ * Clear out any supplemental groups we may have inherited. This
+ * prevents inadvertent creation of files with bad modes (in the
+ * portable version at least, it's certainly possible for PAM
+ * to create a file, and we can't control the code in every
+ * module which might be used).
+ */
+ if (setgroups(0, NULL) < 0)
+ debug("setgroups() failed: %.200s", strerror(errno));
+
+ if (rexec_flag) {
+ if (rexec_argc < 0)
+ fatal("rexec_argc %d < 0", rexec_argc);
+ rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *));
+ for (i = 0; i < (u_int)rexec_argc; i++) {
+ debug("rexec_argv[%d]='%s'", i, saved_argv[i]);
+ rexec_argv[i] = saved_argv[i];
+ }
+ rexec_argv[rexec_argc] = "-R";
+ rexec_argv[rexec_argc + 1] = NULL;
+ }
+ listener_proctitle = prepare_proctitle(ac, av);
+
+ /* Ensure that umask disallows at least group and world write */
+ new_umask = umask(0077) | 0022;
+ (void) umask(new_umask);
+
+ /* Initialize the log (it is reinitialized below in case we forked). */
+ if (debug_flag && (!inetd_flag || rexeced_flag))
+ log_stderr = 1;
+ log_init(__progname, options.log_level,
+ options.log_facility, log_stderr);
+ for (i = 0; i < options.num_log_verbose; i++)
+ log_verbose_add(options.log_verbose[i]);
+
+ /*
+ * If not in debugging mode, not started from inetd and not already
+ * daemonized (eg re-exec via SIGHUP), disconnect from the controlling
+ * terminal, and fork. The original process exits.
+ */
+ already_daemon = daemonized();
+ if (!(debug_flag || inetd_flag || no_daemon_flag || already_daemon)) {
+
+ if (daemon(0, 0) == -1)
+ fatal("daemon() failed: %.200s", strerror(errno));
+
+ disconnect_controlling_tty();
+ }
+ /* Reinitialize the log (because of the fork above). */
+ log_init(__progname, options.log_level, options.log_facility, log_stderr);
+
+ /*
+ * Chdir to the root directory so that the current disk can be
+ * unmounted if desired.
+ */
+ if (chdir("/") == -1)
+ error("chdir(\"/\"): %s", strerror(errno));
+
+ /* ignore SIGPIPE */
+ ssh_signal(SIGPIPE, SIG_IGN);
+
+ /* Get a connection, either from inetd or a listening TCP socket */
+ if (inetd_flag) {
+ server_accept_inetd(&sock_in, &sock_out);
+ } else {
+ platform_pre_listen();
+ server_listen();
+
+ ssh_signal(SIGHUP, sighup_handler);
+ ssh_signal(SIGCHLD, main_sigchld_handler);
+ ssh_signal(SIGTERM, sigterm_handler);
+ ssh_signal(SIGQUIT, sigterm_handler);
+
+ /*
+ * Write out the pid file after the sigterm handler
+ * is setup and the listen sockets are bound
+ */
+ if (options.pid_file != NULL && !debug_flag) {
+ FILE *f = fopen(options.pid_file, "w");
+
+ if (f == NULL) {
+ error("Couldn't create pid file \"%s\": %s",
+ options.pid_file, strerror(errno));
+ } else {
+ fprintf(f, "%ld\n", (long) getpid());
+ fclose(f);
+ }
+ }
+
+ /* Accept a connection and return in a forked child */
+ server_accept_loop(&sock_in, &sock_out,
+ &newsock, config_s);
+ }
+
+ /* This is the child processing a new connection. */
+ setproctitle("%s", "[accepted]");
+
+ /*
+ * Create a new session and process group since the 4.4BSD
+ * setlogin() affects the entire process group. We don't
+ * want the child to be able to affect the parent.
+ */
+ if (!debug_flag && !inetd_flag && setsid() == -1)
+ error("setsid: %.100s", strerror(errno));
+
+ if (rexec_flag) {
+ debug("rexec start in %d out %d newsock %d pipe %d sock %d",
+ sock_in, sock_out, newsock, startup_pipe, config_s[0]);
+ dup2(newsock, STDIN_FILENO);
+ dup2(STDIN_FILENO, STDOUT_FILENO);
+ if (startup_pipe == -1)
+ close(REEXEC_STARTUP_PIPE_FD);
+ else if (startup_pipe != REEXEC_STARTUP_PIPE_FD) {
+ dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD);
+ close(startup_pipe);
+ startup_pipe = REEXEC_STARTUP_PIPE_FD;
+ }
+
+ dup2(config_s[1], REEXEC_CONFIG_PASS_FD);
+ close(config_s[1]);
+
+ ssh_signal(SIGHUP, SIG_IGN); /* avoid reset to SIG_DFL */
+ execv(rexec_argv[0], rexec_argv);
+
+ /* Reexec has failed, fall back and continue */
+ error("rexec of %s failed: %s", rexec_argv[0], strerror(errno));
+ recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL);
+ log_init(__progname, options.log_level,
+ options.log_facility, log_stderr);
+
+ /* Clean up fds */
+ close(REEXEC_CONFIG_PASS_FD);
+ newsock = sock_out = sock_in = dup(STDIN_FILENO);
+ if (stdfd_devnull(1, 1, 0) == -1)
+ error_f("stdfd_devnull failed");
+ debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d",
+ sock_in, sock_out, newsock, startup_pipe, config_s[0]);
+ }
+
+ /* Executed child processes don't need these. */
+ fcntl(sock_out, F_SETFD, FD_CLOEXEC);
+ fcntl(sock_in, F_SETFD, FD_CLOEXEC);
+
+ /* We will not restart on SIGHUP since it no longer makes sense. */
+ ssh_signal(SIGALRM, SIG_DFL);
+ ssh_signal(SIGHUP, SIG_DFL);
+ ssh_signal(SIGTERM, SIG_DFL);
+ ssh_signal(SIGQUIT, SIG_DFL);
+ ssh_signal(SIGCHLD, SIG_DFL);
+ ssh_signal(SIGINT, SIG_DFL);
+
+ /*
+ * Register our connection. This turns encryption off because we do
+ * not have a key.
+ */
+ if ((ssh = ssh_packet_set_connection(NULL, sock_in, sock_out)) == NULL)
+ fatal("Unable to create connection");
+ the_active_state = ssh;
+ ssh_packet_set_server(ssh);
+
+ check_ip_options(ssh);
+
+ /* Prepare the channels layer */
+ channel_init_channels(ssh);
+ channel_set_af(ssh, options.address_family);
+ process_channel_timeouts(ssh, &options);
+ process_permitopen(ssh, &options);
+
+ /* Set SO_KEEPALIVE if requested. */
+ if (options.tcp_keep_alive && ssh_packet_connection_is_on_socket(ssh) &&
+ setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) == -1)
+ error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
+
+ if ((remote_port = ssh_remote_port(ssh)) < 0) {
+ debug("ssh_remote_port failed");
+ cleanup_exit(255);
+ }
+
+ if (options.routing_domain != NULL)
+ set_process_rdomain(ssh, options.routing_domain);
+
+ /*
+ * The rest of the code depends on the fact that
+ * ssh_remote_ipaddr() caches the remote ip, even if
+ * the socket goes away.
+ */
+ remote_ip = ssh_remote_ipaddr(ssh);
+
+#ifdef SSH_AUDIT_EVENTS
+ audit_connection_from(remote_ip, remote_port);
+#endif
+
+ rdomain = ssh_packet_rdomain_in(ssh);
+
+ /* Log the connection. */
+ laddr = get_local_ipaddr(sock_in);
+ verbose("Connection from %s port %d on %s port %d%s%s%s",
+ remote_ip, remote_port, laddr, ssh_local_port(ssh),
+ rdomain == NULL ? "" : " rdomain \"",
+ rdomain == NULL ? "" : rdomain,
+ rdomain == NULL ? "" : "\"");
+ free(laddr);
+
+ /*
+ * We don't want to listen forever unless the other side
+ * successfully authenticates itself. So we set up an alarm which is
+ * cleared after successful authentication. A limit of zero
+ * indicates no limit. Note that we don't set the alarm in debugging
+ * mode; it is just annoying to have the server exit just when you
+ * are about to discover the bug.
+ */
+ ssh_signal(SIGALRM, grace_alarm_handler);
+ if (!debug_flag)
+ alarm(options.login_grace_time);
+
+ if ((r = kex_exchange_identification(ssh, -1,
+ options.version_addendum)) != 0)
+ sshpkt_fatal(ssh, r, "banner exchange");
+
+ ssh_packet_set_nonblocking(ssh);
+
+ /* allocate authentication context */
+ authctxt = xcalloc(1, sizeof(*authctxt));
+ ssh->authctxt = authctxt;
+
+ authctxt->loginmsg = loginmsg;
+
+ /* XXX global for cleanup, access from other modules */
+ the_authctxt = authctxt;
+
+ /* Set default key authentication options */
+ if ((auth_opts = sshauthopt_new_with_keys_defaults()) == NULL)
+ fatal("allocation failed");
+
+ /* prepare buffer to collect messages to display to user after login */
+ if ((loginmsg = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+ auth_debug_reset();
+
+ if (use_privsep) {
+ if (privsep_preauth(ssh) == 1)
+ goto authenticated;
+ } else if (have_agent) {
+ if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
+ error_r(r, "Unable to get agent socket");
+ have_agent = 0;
+ }
+ }
+
+ /* perform the key exchange */
+ /* authenticate user and start session */
+ do_ssh2_kex(ssh);
+ do_authentication2(ssh);
+
+ /*
+ * If we use privilege separation, the unprivileged child transfers
+ * the current keystate and exits
+ */
+ if (use_privsep) {
+ mm_send_keystate(ssh, pmonitor);
+ ssh_packet_clear_keys(ssh);
+ exit(0);
+ }
+
+ authenticated:
+ /*
+ * Cancel the alarm we set to limit the time taken for
+ * authentication.
+ */
+ alarm(0);
+ ssh_signal(SIGALRM, SIG_DFL);
+ authctxt->authenticated = 1;
+ if (startup_pipe != -1) {
+ close(startup_pipe);
+ startup_pipe = -1;
+ }
+
+#ifdef SSH_AUDIT_EVENTS
+ audit_event(ssh, SSH_AUTH_SUCCESS);
+#endif
+
+#ifdef GSSAPI
+ if (options.gss_authentication) {
+ temporarily_use_uid(authctxt->pw);
+ ssh_gssapi_storecreds();
+ restore_uid();
+ }
+#endif
+#ifdef USE_PAM
+ if (options.use_pam) {
+ do_pam_setcred(1);
+ do_pam_session(ssh);
+ }
+#endif
+
+ /*
+ * In privilege separation, we fork another child and prepare
+ * file descriptor passing.
+ */
+ if (use_privsep) {
+ privsep_postauth(ssh, authctxt);
+ /* the monitor process [priv] will not return */
+ }
+
+ ssh_packet_set_timeout(ssh, options.client_alive_interval,
+ options.client_alive_count_max);
+
+ /* Try to send all our hostkeys to the client */
+ notify_hostkeys(ssh);
+
+ /* Start session. */
+ do_authenticated(ssh, authctxt);
+
+ /* The connection has been terminated. */
+ ssh_packet_get_bytes(ssh, &ibytes, &obytes);
+ verbose("Transferred: sent %llu, received %llu bytes",
+ (unsigned long long)obytes, (unsigned long long)ibytes);
+
+ verbose("Closing connection to %.500s port %d", remote_ip, remote_port);
+
+#ifdef USE_PAM
+ if (options.use_pam)
+ finish_pam();
+#endif /* USE_PAM */
+
+#ifdef SSH_AUDIT_EVENTS
+ PRIVSEP(audit_event(ssh, SSH_CONNECTION_CLOSE));
+#endif
+
+ ssh_packet_close(ssh);
+
+ if (use_privsep)
+ mm_terminate();
+
+ exit(0);
+}
+
+int
+sshd_hostkey_sign(struct ssh *ssh, struct sshkey *privkey,
+ struct sshkey *pubkey, u_char **signature, size_t *slenp,
+ const u_char *data, size_t dlen, const char *alg)
+{
+ int r;
+
+ if (use_privsep) {
+ if (privkey) {
+ if (mm_sshkey_sign(ssh, privkey, signature, slenp,
+ data, dlen, alg, options.sk_provider, NULL,
+ ssh->compat) < 0)
+ fatal_f("privkey sign failed");
+ } else {
+ if (mm_sshkey_sign(ssh, pubkey, signature, slenp,
+ data, dlen, alg, options.sk_provider, NULL,
+ ssh->compat) < 0)
+ fatal_f("pubkey sign failed");
+ }
+ } else {
+ if (privkey) {
+ if (sshkey_sign(privkey, signature, slenp, data, dlen,
+ alg, options.sk_provider, NULL, ssh->compat) < 0)
+ fatal_f("privkey sign failed");
+ } else {
+ if ((r = ssh_agent_sign(auth_sock, pubkey,
+ signature, slenp, data, dlen, alg,
+ ssh->compat)) != 0) {
+ fatal_fr(r, "agent sign failed");
+ }
+ }
+ }
+ return 0;
+}
+
+/* SSH2 key exchange */
+static void
+do_ssh2_kex(struct ssh *ssh)
+{
+ char *myproposal[PROPOSAL_MAX] = { KEX_SERVER };
+ struct kex *kex;
+ char *prop_kex = NULL, *prop_enc = NULL, *prop_hostkey = NULL;
+ int r;
+
+ myproposal[PROPOSAL_KEX_ALGS] = prop_kex = compat_kex_proposal(ssh,
+ options.kex_algorithms);
+ myproposal[PROPOSAL_ENC_ALGS_CTOS] =
+ myproposal[PROPOSAL_ENC_ALGS_STOC] = prop_enc =
+ compat_cipher_proposal(ssh, options.ciphers);
+ myproposal[PROPOSAL_MAC_ALGS_CTOS] =
+ myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
+
+ if (options.compression == COMP_NONE) {
+ myproposal[PROPOSAL_COMP_ALGS_CTOS] =
+ myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
+ }
+
+ if (options.rekey_limit || options.rekey_interval)
+ ssh_packet_set_rekey_limits(ssh, options.rekey_limit,
+ options.rekey_interval);
+
+ myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = prop_hostkey =
+ compat_pkalg_proposal(ssh, list_hostkey_types());
+
+ /* start key exchange */
+ if ((r = kex_setup(ssh, myproposal)) != 0)
+ fatal_r(r, "kex_setup");
+ kex = ssh->kex;
+#ifdef WITH_OPENSSL
+ kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_server;
+ kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_server;
+ kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_server;
+ kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_server;
+ kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_server;
+ kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
+ kex->kex[KEX_DH_GEX_SHA256] = kexgex_server;
+# ifdef OPENSSL_HAS_ECC
+ kex->kex[KEX_ECDH_SHA2] = kex_gen_server;
+# endif
+#endif
+ kex->kex[KEX_C25519_SHA256] = kex_gen_server;
+ kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server;
+ kex->load_host_public_key=&get_hostkey_public_by_type;
+ kex->load_host_private_key=&get_hostkey_private_by_type;
+ kex->host_key_index=&get_hostkey_index;
+ kex->sign = sshd_hostkey_sign;
+
+ ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &kex->done);
+
+#ifdef DEBUG_KEXDH
+ /* send 1st encrypted/maced/compressed message */
+ if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 ||
+ (r = sshpkt_put_cstring(ssh, "markus")) != 0 ||
+ (r = sshpkt_send(ssh)) != 0 ||
+ (r = ssh_packet_write_wait(ssh)) != 0)
+ fatal_fr(r, "send test");
+#endif
+ free(prop_kex);
+ free(prop_enc);
+ free(prop_hostkey);
+ debug("KEX done");
+}
+
+/* server specific fatal cleanup */
+void
+cleanup_exit(int i)
+{
+ if (the_active_state != NULL && the_authctxt != NULL) {
+ do_cleanup(the_active_state, the_authctxt);
+ if (use_privsep && privsep_is_preauth &&
+ pmonitor != NULL && pmonitor->m_pid > 1) {
+ debug("Killing privsep child %d", pmonitor->m_pid);
+ if (kill(pmonitor->m_pid, SIGKILL) != 0 &&
+ errno != ESRCH) {
+ error_f("kill(%d): %s", pmonitor->m_pid,
+ strerror(errno));
+ }
+ }
+ }
+#ifdef SSH_AUDIT_EVENTS
+ /* done after do_cleanup so it can cancel the PAM auth 'thread' */
+ if (the_active_state != NULL && (!use_privsep || mm_is_monitor()))
+ audit_event(the_active_state, SSH_CONNECTION_ABANDON);
+#endif
+ _exit(i);
+}