X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/5ca51e190d8991e7cf2e8076dbd4d3dfbb50c966..8f73f7bbad3099712a0fdbc599a1b68058b12a3d:/sshd.c

diff --git a/sshd.c b/sshd.c
index 22eabcda..47df9caf 100644
--- a/sshd.c
+++ b/sshd.c
@@ -15,8 +15,10 @@
  * called by a name other than "ssh" or "Secure Shell".
  *
  * SSH2 implementation:
+ * Privilege Separation:
  *
- * Copyright (c) 2000 Markus Friedl.  All rights reserved.
+ * 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
@@ -40,18 +42,23 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshd.c,v 1.165 2001/02/08 19:30:53 itojun Exp $");
+RCSID("$OpenBSD: sshd.c,v 1.276 2003/08/28 12:54:34 markus Exp $");
 
 #include <openssl/dh.h>
 #include <openssl/bn.h>
-#include <openssl/hmac.h>
+#include <openssl/md5.h>
+#include <openssl/rand.h>
+#ifdef HAVE_SECUREWARE
+#include <sys/security.h>
+#include <prot.h>
+#endif
 
 #include "ssh.h"
 #include "ssh1.h"
 #include "ssh2.h"
 #include "xmalloc.h"
 #include "rsa.h"
-#include "pty.h"
+#include "sshpty.h"
 #include "packet.h"
 #include "mpaux.h"
 #include "log.h"
@@ -70,6 +77,13 @@ RCSID("$OpenBSD: sshd.c,v 1.165 2001/02/08 19:30:53 itojun Exp $");
 #include "canohost.h"
 #include "auth.h"
 #include "misc.h"
+#include "dispatch.h"
+#include "channels.h"
+#include "session.h"
+#include "monitor_mm.h"
+#include "monitor.h"
+#include "monitor_wrap.h"
+#include "monitor_fdpass.h"
 
 #ifdef LIBWRAP
 #include <tcpd.h>
@@ -98,11 +112,7 @@ char *config_file_name = _PATH_SERVER_CONFIG_FILE;
  * Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
  * Default value is AF_UNSPEC means both IPv4 and IPv6.
  */
-#ifdef IPV4_DEFAULT
-int IPv4or6 = AF_INET;
-#else
 int IPv4or6 = AF_UNSPEC;
-#endif
 
 /*
  * Debug mode flag.  This can be set on the command line.  If debug
@@ -112,6 +122,9 @@ int IPv4or6 = AF_UNSPEC;
  */
 int debug_flag = 0;
 
+/* Flag indicating that the daemon should only test the configuration and keys. */
+int test_flag = 0;
+
 /* Flag indicating that the daemon is being started from inetd. */
 int inetd_flag = 0;
 
@@ -140,6 +153,9 @@ int num_listen_socks = 0;
 char *client_version_string = NULL;
 char *server_version_string = NULL;
 
+/* for rekeying XXX fixme */
+Kex *xxx_kex;
+
 /*
  * Any really sensitive data in the application is contained in this
  * structure. The idea is that this structure could be locked into memory so
@@ -149,102 +165,129 @@ char *server_version_string = NULL;
  * not very useful.  Currently, memory locking is not implemented.
  */
 struct {
-	Key	*server_key;		/* empheral server key */
+	Key	*server_key;		/* ephemeral server key */
 	Key	*ssh1_host_key;		/* ssh1 host key */
 	Key	**host_keys;		/* all private host keys */
 	int	have_ssh1_key;
 	int	have_ssh2_key;
+	u_char	ssh1_cookie[SSH_SESSION_KEY_LENGTH];
 } sensitive_data;
 
 /*
  * Flag indicating whether the RSA server key needs to be regenerated.
  * Is set in the SIGALRM handler and cleared when the key is regenerated.
  */
-int key_do_regen = 0;
+static volatile sig_atomic_t key_do_regen = 0;
 
-/* This is set to true when SIGHUP is received. */
-int received_sighup = 0;
+/* 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;
 
 /* session identifier, used by RSA-auth */
 u_char session_id[16];
 
 /* same for ssh2 */
 u_char *session_id2 = NULL;
-int session_id2_len = 0;
+u_int session_id2_len = 0;
 
 /* record remote hostname or ip */
 u_int utmp_len = MAXHOSTNAMELEN;
 
+/* options.max_startup sized array of fd ints */
+int *startup_pipes = NULL;
+int startup_pipe;		/* in child */
+
+/* variables used for privilege separation */
+int use_privsep;
+struct monitor *pmonitor;
+
+/* message to be displayed after login */
+Buffer loginmsg;
+
 /* Prototypes for various functions defined later in this file. */
-void do_ssh1_kex(void);
-void do_ssh2_kex(void);
+void destroy_sensitive_data(void);
+void demote_sensitive_data(void);
 
-void ssh_dh1_server(Kex *, Buffer *_kexinit, Buffer *);
-void ssh_dhgex_server(Kex *, Buffer *_kexinit, Buffer *);
+static void do_ssh1_kex(void);
+static void do_ssh2_kex(void);
 
 /*
  * Close all listening sockets
  */
-void
+static void
 close_listen_socks(void)
 {
 	int i;
+
 	for (i = 0; i < num_listen_socks; i++)
 		close(listen_socks[i]);
 	num_listen_socks = -1;
 }
 
+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).
  */
-void
+static void
 sighup_handler(int sig)
 {
+	int save_errno = errno;
+
 	received_sighup = 1;
 	signal(SIGHUP, sighup_handler);
+	errno = save_errno;
 }
 
 /*
  * Called from the main program after receiving SIGHUP.
  * Restarts the server.
  */
-void
+static void
 sighup_restart(void)
 {
-	log("Received SIGHUP; restarting.");
+	logit("Received SIGHUP; restarting.");
 	close_listen_socks();
+	close_startup_pipes();
 	execv(saved_argv[0], saved_argv);
-	log("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], strerror(errno));
+	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.
- * These close the listen socket; not closing it seems to cause "Address
- * already in use" problems on some machines, which is inconvenient.
  */
-void
+static void
 sigterm_handler(int sig)
 {
-	log("Received signal %d; terminating.", sig);
-	close_listen_socks();
-	unlink(options.pid_file);
-	exit(255);
+	received_sigterm = sig;
 }
 
 /*
  * SIGCHLD handler.  This is called whenever a child dies.  This will then
- * reap any zombies left by exited c.
+ * reap any zombies left by exited children.
  */
-void
+static void
 main_sigchld_handler(int sig)
 {
 	int save_errno = errno;
+	pid_t pid;
 	int status;
 
-	while (waitpid(-1, &status, WNOHANG) > 0)
+	while ((pid = waitpid(-1, &status, WNOHANG)) > 0 ||
+	    (pid < 0 && errno == EINTR))
 		;
 
 	signal(SIGCHLD, main_sigchld_handler);
@@ -254,14 +297,13 @@ main_sigchld_handler(int sig)
 /*
  * Signal handler for the alarm after the login grace period has expired.
  */
-void
+static void
 grace_alarm_handler(int sig)
 {
-	/* Close the connection. */
-	packet_close();
+	/* XXX no idea how fix this signal handler */
 
 	/* Log error and exit. */
-	fatal("Timeout before authentication for %s.", get_remote_ipaddr());
+	fatal("Timeout before authentication for %s", get_remote_ipaddr());
 }
 
 /*
@@ -271,28 +313,40 @@ grace_alarm_handler(int sig)
  * Thus there should be no concurrency control/asynchronous execution
  * problems.
  */
-void
-generate_empheral_server_key(void)
+static void
+generate_ephemeral_server_key(void)
 {
-	log("Generating %s%d bit RSA key.", sensitive_data.server_key ? "new " : "",
-	    options.server_key_bits);
+	u_int32_t rnd = 0;
+	int i;
+
+	verbose("Generating %s%d bit RSA key.",
+	    sensitive_data.server_key ? "new " : "", options.server_key_bits);
 	if (sensitive_data.server_key != NULL)
 		key_free(sensitive_data.server_key);
-	sensitive_data.server_key = key_generate(KEY_RSA1, options.server_key_bits);
+	sensitive_data.server_key = key_generate(KEY_RSA1,
+	    options.server_key_bits);
+	verbose("RSA key generation complete.");
+
+	for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
+		if (i % 4 == 0)
+			rnd = arc4random();
+		sensitive_data.ssh1_cookie[i] = rnd & 0xff;
+		rnd >>= 8;
+	}
 	arc4random_stir();
-	log("RSA key generation complete.");
 }
 
-void
+static void
 key_regeneration_alarm(int sig)
 {
 	int save_errno = errno;
+
 	signal(SIGALRM, SIG_DFL);
 	errno = save_errno;
 	key_do_regen = 1;
 }
 
-void
+static void
 sshd_exchange_identification(int sock_in, int sock_out)
 {
 	int i, mismatch;
@@ -316,38 +370,37 @@ sshd_exchange_identification(int sock_in, int sock_out)
 	snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION);
 	server_version_string = xstrdup(buf);
 
-	if (client_version_string == NULL) {
-		/* Send our protocol version identification. */
-		if (atomicio(write, sock_out, server_version_string, strlen(server_version_string))
-		    != strlen(server_version_string)) {
-			log("Could not write ident string to %s.", get_remote_ipaddr());
+	/* Send our protocol version identification. */
+	if (atomicio(vwrite, sock_out, server_version_string,
+	    strlen(server_version_string))
+	    != strlen(server_version_string)) {
+		logit("Could not write ident string to %s", get_remote_ipaddr());
+		fatal_cleanup();
+	}
+
+	/* Read other sides version identification. */
+	memset(buf, 0, sizeof(buf));
+	for (i = 0; i < sizeof(buf) - 1; i++) {
+		if (atomicio(read, sock_in, &buf[i], 1) != 1) {
+			logit("Did not receive identification string from %s",
+			    get_remote_ipaddr());
 			fatal_cleanup();
 		}
-
-		/* Read other side\'s version identification. */
-		for (i = 0; i < sizeof(buf) - 1; i++) {
-			if (atomicio(read, sock_in, &buf[i], 1) != 1) {
-				log("Did not receive ident string from %s.", get_remote_ipaddr());
-				fatal_cleanup();
-			}
-			if (buf[i] == '\r') {
-				buf[i] = '\n';
-				buf[i + 1] = 0;
-				/* Kludge for F-Secure Macintosh < 1.0.2 */
-				if (i == 12 &&
-				    strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
-					break;
-				continue;
-			}
-			if (buf[i] == '\n') {
-				/* buf[i] == '\n' */
-				buf[i + 1] = 0;
+		if (buf[i] == '\r') {
+			buf[i] = 0;
+			/* Kludge for F-Secure Macintosh < 1.0.2 */
+			if (i == 12 &&
+			    strncmp(buf, "SSH-1.5-W1.0", 12) == 0)
 				break;
-			}
+			continue;
+		}
+		if (buf[i] == '\n') {
+			buf[i] = 0;
+			break;
 		}
-		buf[sizeof(buf) - 1] = 0;
-		client_version_string = xstrdup(buf);
 	}
+	buf[sizeof(buf) - 1] = 0;
+	client_version_string = xstrdup(buf);
 
 	/*
 	 * Check that the versions match.  In future this might accept
@@ -356,20 +409,32 @@ sshd_exchange_identification(int sock_in, int sock_out)
 	if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n",
 	    &remote_major, &remote_minor, remote_version) != 3) {
 		s = "Protocol mismatch.\n";
-		(void) atomicio(write, sock_out, s, strlen(s));
+		(void) atomicio(vwrite, sock_out, s, strlen(s));
 		close(sock_in);
 		close(sock_out);
-		log("Bad protocol version identification '%.100s' from %s",
+		logit("Bad protocol version identification '%.100s' from %s",
 		    client_version_string, get_remote_ipaddr());
 		fatal_cleanup();
 	}
 	debug("Client protocol version %d.%d; client software version %.100s",
-	      remote_major, remote_minor, remote_version);
+	    remote_major, remote_minor, remote_version);
 
 	compat_datafellows(remote_version);
 
+	if (datafellows & SSH_BUG_PROBE) {
+		logit("probed from %s with %s.  Don't panic.",
+		    get_remote_ipaddr(), client_version_string);
+		fatal_cleanup();
+	}
+
+	if (datafellows & SSH_BUG_SCANNER) {
+		logit("scanned from %s with %s.  Don't panic.",
+		    get_remote_ipaddr(), client_version_string);
+		fatal_cleanup();
+	}
+
 	mismatch = 0;
-	switch(remote_major) {
+	switch (remote_major) {
 	case 1:
 		if (remote_minor == 99) {
 			if (options.protocol & SSH_PROTO_2)
@@ -401,24 +466,20 @@ sshd_exchange_identification(int sock_in, int sock_out)
 		break;
 	}
 	chop(server_version_string);
-	chop(client_version_string);
 	debug("Local version string %.200s", server_version_string);
 
 	if (mismatch) {
 		s = "Protocol major versions differ.\n";
-		(void) atomicio(write, sock_out, s, strlen(s));
+		(void) atomicio(vwrite, sock_out, s, strlen(s));
 		close(sock_in);
 		close(sock_out);
-		log("Protocol major versions differ for %s: %.200s vs. %.200s",
+		logit("Protocol major versions differ for %s: %.200s vs. %.200s",
 		    get_remote_ipaddr(),
 		    server_version_string, client_version_string);
 		fatal_cleanup();
 	}
-	if (compat20)
-		packet_set_ssh2_format();
 }
 
-
 /* Destroy the host and server keys.  They will no longer be needed. */
 void
 destroy_sensitive_data(void)
@@ -429,78 +490,226 @@ destroy_sensitive_data(void)
 		key_free(sensitive_data.server_key);
 		sensitive_data.server_key = NULL;
 	}
-	for(i = 0; i < options.num_host_key_files; i++) {
+	for (i = 0; i < options.num_host_key_files; i++) {
 		if (sensitive_data.host_keys[i]) {
 			key_free(sensitive_data.host_keys[i]);
 			sensitive_data.host_keys[i] = NULL;
 		}
 	}
 	sensitive_data.ssh1_host_key = NULL;
+	memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH);
 }
-Key *
-load_private_key_autodetect(const char *filename)
+
+/* Demote private to public keys for network child */
+void
+demote_sensitive_data(void)
 {
-	struct stat st;
-	int type;
-	Key *public, *private;
+	Key *tmp;
+	int i;
 
-	if (stat(filename, &st) < 0) {
-		perror(filename);
-		return NULL;
+	if (sensitive_data.server_key) {
+		tmp = key_demote(sensitive_data.server_key);
+		key_free(sensitive_data.server_key);
+		sensitive_data.server_key = tmp;
 	}
-	/*
-	 * try to load the public key. right now this only works for RSA1,
-	 * since SSH2 keys are fully encrypted
-	 */
-	type = KEY_RSA1;
-	public = key_new(type);
-	if (!load_public_key(filename, public, NULL)) {
-		/* ok, so we will assume this is 'some' key */
-		type = KEY_UNSPEC;
+
+	for (i = 0; i < options.num_host_key_files; i++) {
+		if (sensitive_data.host_keys[i]) {
+			tmp = key_demote(sensitive_data.host_keys[i]);
+			key_free(sensitive_data.host_keys[i]);
+			sensitive_data.host_keys[i] = tmp;
+			if (tmp->type == KEY_RSA1)
+				sensitive_data.ssh1_host_key = tmp;
+		}
 	}
-	key_free(public);
-
-	/* Ok, try key with empty passphrase */
-	private = key_new(type);
-	if (load_private_key(filename, "", private, NULL)) {
-		debug("load_private_key_autodetect: type %d %s",
-		    private->type, key_type(private));
-		return private;
+
+	/* We do not clear ssh1_host key and cookie.  XXX - Okay Niels? */
+}
+
+static void
+privsep_preauth_child(void)
+{
+	u_int32_t rnd[256];
+	gid_t gidset[1];
+	struct passwd *pw;
+	int i;
+
+	/* Enable challenge-response authentication for privilege separation */
+	privsep_challenge_enable();
+
+	for (i = 0; i < 256; i++)
+		rnd[i] = arc4random();
+	RAND_seed(rnd, sizeof(rnd));
+
+	/* Demote the private keys to public keys. */
+	demote_sensitive_data();
+
+	if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
+		fatal("Privilege separation user %s does not exist",
+		    SSH_PRIVSEP_USER);
+	memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
+	endpwent();
+
+	/* 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)pw->pw_uid,
+	    (u_int)pw->pw_gid);
+#if 0
+	/* XXX not ready, to heavy after chroot */
+	do_setusercontext(pw);
+#else
+	gidset[0] = pw->pw_gid;
+	if (setgroups(1, gidset) < 0)
+		fatal("setgroups: %.100s", strerror(errno));
+	permanently_set_uid(pw);
+#endif
+}
+
+static Authctxt *
+privsep_preauth(void)
+{
+	Authctxt *authctxt = NULL;
+	int status;
+	pid_t pid;
+
+	/* 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 = &xxx_kex;
+
+	pid = fork();
+	if (pid == -1) {
+		fatal("fork of unprivileged child failed");
+	} else if (pid != 0) {
+		fatal_remove_cleanup((void (*) (void *)) packet_close, NULL);
+
+		debug2("Network child is on pid %ld", (long)pid);
+
+		close(pmonitor->m_recvfd);
+		authctxt = monitor_child_preauth(pmonitor);
+		close(pmonitor->m_sendfd);
+
+		/* Sync memory */
+		monitor_sync(pmonitor);
+
+		/* Wait for the child's exit status */
+		while (waitpid(pid, &status, 0) < 0)
+			if (errno != EINTR)
+				break;
+
+		/* Reinstall, since the child has finished */
+		fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
+
+		return (authctxt);
+	} else {
+		/* child */
+
+		close(pmonitor->m_sendfd);
+
+		/* Demote the child */
+		if (getuid() == 0 || geteuid() == 0)
+			privsep_preauth_child();
+		setproctitle("%s", "[net]");
 	}
-	key_free(private);
-	return NULL;
+	return (NULL);
+}
+
+static void
+privsep_postauth(Authctxt *authctxt)
+{
+	extern Authctxt *x_authctxt;
+
+	/* XXX - Remote port forwarding */
+	x_authctxt = authctxt;
+
+#ifdef DISABLE_FD_PASSING
+	if (1) {
+#else
+	if (authctxt->pw->pw_uid == 0 || options.use_login) {
+#endif
+		/* File descriptor passing is broken or root login */
+		monitor_apply_keystate(pmonitor);
+		use_privsep = 0;
+		return;
+	}
+
+	/* Authentication complete */
+	alarm(0);
+	if (startup_pipe != -1) {
+		close(startup_pipe);
+		startup_pipe = -1;
+	}
+
+	/* 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) {
+		fatal_remove_cleanup((void (*) (void *)) packet_close, NULL);
+
+		debug2("User child is on pid %ld", (long)pmonitor->m_pid);
+		close(pmonitor->m_recvfd);
+		monitor_child_postauth(pmonitor);
+
+		/* NEVERREACHED */
+		exit(0);
+	}
+
+	close(pmonitor->m_sendfd);
+
+	/* Demote the private keys to public keys. */
+	demote_sensitive_data();
+
+	/* Drop privileges */
+	do_setusercontext(authctxt->pw);
+
+	/* It is safe now to apply the key state */
+	monitor_apply_keystate(pmonitor);
 }
 
-char *
+static char *
 list_hostkey_types(void)
 {
-	static char buf[1024];
+	Buffer b;
+	char *p;
 	int i;
-	buf[0] = '\0';
-	for(i = 0; i < options.num_host_key_files; i++) {
+
+	buffer_init(&b);
+	for (i = 0; i < options.num_host_key_files; i++) {
 		Key *key = sensitive_data.host_keys[i];
 		if (key == NULL)
 			continue;
-		switch(key->type) {
+		switch (key->type) {
 		case KEY_RSA:
 		case KEY_DSA:
-			strlcat(buf, key_ssh_name(key), sizeof buf);
-			strlcat(buf, ",", sizeof buf);
+			if (buffer_len(&b) > 0)
+				buffer_append(&b, ",", 1);
+			p = key_ssh_name(key);
+			buffer_append(&b, p, strlen(p));
 			break;
 		}
 	}
-	i = strlen(buf);
-	if (i > 0 && buf[i-1] == ',')
-		buf[i-1] = '\0';
-	debug("list_hostkey_types: %s", buf);
-	return buf;
+	buffer_append(&b, "\0", 1);
+	p = xstrdup(buffer_ptr(&b));
+	buffer_free(&b);
+	debug("list_hostkey_types: %s", p);
+	return p;
 }
 
 Key *
 get_hostkey_by_type(int type)
 {
 	int i;
-	for(i = 0; i < options.num_host_key_files; i++) {
+
+	for (i = 0; i < options.num_host_key_files; i++) {
 		Key *key = sensitive_data.host_keys[i];
 		if (key != NULL && key->type == type)
 			return key;
@@ -508,13 +717,33 @@ get_hostkey_by_type(int type)
 	return NULL;
 }
 
+Key *
+get_hostkey_by_index(int ind)
+{
+	if (ind < 0 || ind >= options.num_host_key_files)
+		return (NULL);
+	return (sensitive_data.host_keys[ind]);
+}
+
+int
+get_hostkey_index(Key *key)
+{
+	int i;
+
+	for (i = 0; i < options.num_host_key_files; i++) {
+		if (key == sensitive_data.host_keys[i])
+			return (i);
+	}
+	return (-1);
+}
+
 /*
  * 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
  */
-int
+static int
 drop_connection(int startups)
 {
 	double p, r;
@@ -537,8 +766,30 @@ drop_connection(int startups)
 	return (r < p) ? 1 : 0;
 }
 
-int *startup_pipes = NULL;	/* options.max_startup sized array of fd ints */
-int startup_pipe;		/* in child */
+static void
+usage(void)
+{
+	fprintf(stderr, "sshd version %s\n", SSH_VERSION);
+	fprintf(stderr, "Usage: %s [options]\n", __progname);
+	fprintf(stderr, "Options:\n");
+	fprintf(stderr, "  -f file    Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE);
+	fprintf(stderr, "  -d         Debugging mode (multiple -d means more debugging)\n");
+	fprintf(stderr, "  -i         Started from inetd\n");
+	fprintf(stderr, "  -D         Do not fork into daemon mode\n");
+	fprintf(stderr, "  -t         Only test configuration file and keys\n");
+	fprintf(stderr, "  -q         Quiet (no logging)\n");
+	fprintf(stderr, "  -p port    Listen on the specified port (default: 22)\n");
+	fprintf(stderr, "  -k seconds Regenerate server key every this many seconds (default: 3600)\n");
+	fprintf(stderr, "  -g seconds Grace period for authentication (default: 600)\n");
+	fprintf(stderr, "  -b bits    Size of server RSA key (default: 768 bits)\n");
+	fprintf(stderr, "  -h file    File from which to read host key (default: %s)\n",
+	    _PATH_HOST_KEY_FILE);
+	fprintf(stderr, "  -u len     Maximum hostname length for utmp recording\n");
+	fprintf(stderr, "  -4         Use IPv4 only\n");
+	fprintf(stderr, "  -6         Use IPv6 only\n");
+	fprintf(stderr, "  -o option  Process the option as if it was read from a configuration file.\n");
+	exit(1);
+}
 
 /*
  * Main program for the daemon.
@@ -556,26 +807,39 @@ main(int ac, char **av)
 	const char *remote_ip;
 	int remote_port;
 	FILE *f;
-	struct linger linger;
 	struct addrinfo *ai;
 	char ntop[NI_MAXHOST], strport[NI_MAXSERV];
 	int listen_sock, maxfd;
 	int startup_p[2];
 	int startups = 0;
+	Authctxt *authctxt;
+	Key *key;
 	int ret, key_used = 0;
 
-	__progname = get_progname(av[0]);
+#ifdef HAVE_SECUREWARE
+	(void)set_auth_parameters(ac, av);
+#endif
+	__progname = ssh_get_progname(av[0]);
 	init_rng();
 
-	/* Save argv. */
+	/* Save argv. Duplicate so setproctitle emulation doesn't clobber it */
 	saved_argc = ac;
-	saved_argv = av;
+	saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1));
+	for (i = 0; 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
 
 	/* Initialize configuration options to their default values. */
 	initialize_server_options(&options);
 
 	/* Parse command-line arguments. */
-	while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:u:dDiqQ46")) != -1) {
+	while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqtQ46")) != -1) {
 		switch (opt) {
 		case '4':
 			IPv4or6 = AF_INET;
@@ -587,19 +851,18 @@ main(int ac, char **av)
 			config_file_name = optarg;
 			break;
 		case 'd':
-			if (0 == debug_flag) {
+			if (debug_flag == 0) {
 				debug_flag = 1;
 				options.log_level = SYSLOG_LEVEL_DEBUG1;
-			} else if (options.log_level < SYSLOG_LEVEL_DEBUG3) {
+			} else if (options.log_level < SYSLOG_LEVEL_DEBUG3)
 				options.log_level++;
-			} else {
-				fprintf(stderr, "Too high debugging level.\n");
-				exit(1);
-			}
 			break;
 		case 'D':
 			no_daemon_flag = 1;
 			break;
+		case 'e':
+			log_stderr = 1;
+			break;
 		case 'i':
 			inetd_flag = 1;
 			break;
@@ -618,13 +881,23 @@ main(int ac, char **av)
 				fprintf(stderr, "too many ports.\n");
 				exit(1);
 			}
-			options.ports[options.num_ports++] = atoi(optarg);
+			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':
-			options.login_grace_time = atoi(optarg);
+			if ((options.login_grace_time = convtime(optarg)) == -1) {
+				fprintf(stderr, "Invalid login grace time.\n");
+				exit(1);
+			}
 			break;
 		case 'k':
-			options.key_regeneration_time = atoi(optarg);
+			if ((options.key_regeneration_time = convtime(optarg)) == -1) {
+				fprintf(stderr, "Invalid key regeneration interval.\n");
+				exit(1);
+			}
 			break;
 		case 'h':
 			if (options.num_host_key_files >= MAX_HOSTKEYS) {
@@ -633,45 +906,49 @@ main(int ac, char **av)
 			}
 			options.host_key_files[options.num_host_key_files++] = optarg;
 			break;
-		case 'V':
-			client_version_string = optarg;
-			/* only makes sense with inetd_flag, i.e. no listen() */
-			inetd_flag = 1;
+		case 't':
+			test_flag = 1;
 			break;
 		case 'u':
 			utmp_len = atoi(optarg);
+			if (utmp_len > MAXHOSTNAMELEN) {
+				fprintf(stderr, "Invalid utmp length.\n");
+				exit(1);
+			}
+			break;
+		case 'o':
+			if (process_server_config_line(&options, optarg,
+			    "command-line", 0) != 0)
+				exit(1);
 			break;
 		case '?':
 		default:
-			fprintf(stderr, "sshd version %s\n", SSH_VERSION);
-			fprintf(stderr, "Usage: %s [options]\n", __progname);
-			fprintf(stderr, "Options:\n");
-			fprintf(stderr, "  -f file    Configuration file (default %s)\n", _PATH_SERVER_CONFIG_FILE);
-			fprintf(stderr, "  -d         Debugging mode (multiple -d means more debugging)\n");
-			fprintf(stderr, "  -i         Started from inetd\n");
-			fprintf(stderr, "  -D         Do not fork into daemon mode\n");
-			fprintf(stderr, "  -q         Quiet (no logging)\n");
-			fprintf(stderr, "  -p port    Listen on the specified port (default: 22)\n");
-			fprintf(stderr, "  -k seconds Regenerate server key every this many seconds (default: 3600)\n");
-			fprintf(stderr, "  -g seconds Grace period for authentication (default: 600)\n");
-			fprintf(stderr, "  -b bits    Size of server RSA key (default: 768 bits)\n");
-			fprintf(stderr, "  -h file    File from which to read host key (default: %s)\n",
-			    _PATH_HOST_KEY_FILE);
-			fprintf(stderr, "  -u len     Maximum hostname length for utmp recording\n");
-			fprintf(stderr, "  -4         Use IPv4 only\n");
-			fprintf(stderr, "  -6         Use IPv6 only\n");
-			exit(1);
+			usage();
+			break;
 		}
 	}
+	SSLeay_add_all_algorithms();
+	channel_set_af(IPv4or6);
 
 	/*
 	 * Force logging to stderr until we have loaded the private host
 	 * key (unless started from inetd)
 	 */
 	log_init(__progname,
-	    options.log_level == -1 ? SYSLOG_LEVEL_INFO : options.log_level,
-	    options.log_facility == -1 ? SYSLOG_FACILITY_AUTH : options.log_facility,
-	    !inetd_flag);
+	    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);
+
+#ifdef _UNICOS
+	/* Cray can define user privs drop all prives now!
+	 * Not needed on PRIV_SU systems!
+	 */
+	drop_cray_privs();
+#endif
+
+	seed_rng();
 
 	/* Read server configuration options from the configuration file. */
 	read_server_config(&options, config_file_name);
@@ -688,22 +965,25 @@ main(int ac, char **av)
 	debug("sshd version %.100s", SSH_VERSION);
 
 	/* load private host keys */
-	sensitive_data.host_keys = xmalloc(options.num_host_key_files*sizeof(Key*));
-	for(i = 0; i < options.num_host_key_files; i++)
+	sensitive_data.host_keys = xmalloc(options.num_host_key_files *
+	    sizeof(Key *));
+	for (i = 0; i < options.num_host_key_files; i++)
 		sensitive_data.host_keys[i] = NULL;
 	sensitive_data.server_key = NULL;
 	sensitive_data.ssh1_host_key = NULL;
 	sensitive_data.have_ssh1_key = 0;
 	sensitive_data.have_ssh2_key = 0;
 
-	for(i = 0; i < options.num_host_key_files; i++) {
-		Key *key = load_private_key_autodetect(options.host_key_files[i]);
+	for (i = 0; i < options.num_host_key_files; i++) {
+		key = key_load_private(options.host_key_files[i], "", NULL);
+		sensitive_data.host_keys[i] = key;
 		if (key == NULL) {
-			error("Could not load host key: %.200s: %.100s",
-			    options.host_key_files[i], strerror(errno));
+			error("Could not load host key: %s",
+			    options.host_key_files[i]);
+			sensitive_data.host_keys[i] = NULL;
 			continue;
 		}
-		switch(key->type){
+		switch (key->type) {
 		case KEY_RSA1:
 			sensitive_data.ssh1_host_key = key;
 			sensitive_data.have_ssh1_key = 1;
@@ -713,18 +993,19 @@ main(int ac, char **av)
 			sensitive_data.have_ssh2_key = 1;
 			break;
 		}
-		sensitive_data.host_keys[i] = key;
+		debug("private host key: #%d type %d %s", i, key->type,
+		    key_type(key));
 	}
 	if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) {
-		log("Disabling protocol version 1. Could not load host key");
+		logit("Disabling protocol version 1. Could not load host key");
 		options.protocol &= ~SSH_PROTO_1;
 	}
 	if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) {
-		log("Disabling protocol version 2. Could not load host key");
+		logit("Disabling protocol version 2. Could not load host key");
 		options.protocol &= ~SSH_PROTO_2;
 	}
 	if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) {
-		log("sshd: no hostkeys available -- exiting.\n");
+		logit("sshd: no hostkeys available -- exiting.");
 		exit(1);
 	}
 
@@ -741,19 +1022,54 @@ main(int ac, char **av)
 		 * hate software patents. I dont know if this can go? Niels
 		 */
 		if (options.server_key_bits >
-		    BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - SSH_KEY_BITS_RESERVED &&
-		    options.server_key_bits <
-		    BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
+		    BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) -
+		    SSH_KEY_BITS_RESERVED && options.server_key_bits <
+		    BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
+		    SSH_KEY_BITS_RESERVED) {
 			options.server_key_bits =
-			    BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED;
+			    BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) +
+			    SSH_KEY_BITS_RESERVED;
 			debug("Forcing server key to %d bits to make it differ from host key.",
 			    options.server_key_bits);
 		}
 	}
 
-#ifdef HAVE_SCO_PROTECTED_PW
-	(void) set_auth_parameters(ac, av);
+	if (use_privsep) {
+		struct passwd *pw;
+		struct stat st;
+
+		if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL)
+			fatal("Privilege separation user %s does not exist",
+			    SSH_PRIVSEP_USER);
+		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);
+	}
+
+	/* 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));
 
 	/* Initialize the log (it is reinitialized below in case we forked). */
 	if (debug_flag && !inetd_flag)
@@ -791,11 +1107,14 @@ main(int ac, char **av)
 	   unmounted if desired. */
 	chdir("/");
 
+	/* ignore SIGPIPE */
+	signal(SIGPIPE, SIG_IGN);
+
 	/* Start listening for a socket, unless started from inetd. */
 	if (inetd_flag) {
-		int s1, s2;
+		int s1;
 		s1 = dup(0);	/* Make sure descriptors 0, 1, and 2 are in use. */
-		s2 = dup(s1);
+		dup(s1);
 		sock_in = dup(0);
 		sock_out = dup(1);
 		startup_pipe = -1;
@@ -806,7 +1125,7 @@ main(int ac, char **av)
 		 */
 		debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
 		if (options.protocol & SSH_PROTO_1)
-			generate_empheral_server_key();
+			generate_ephemeral_server_key();
 	} else {
 		for (ai = options.listen_addrs; ai; ai = ai->ai_next) {
 			if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
@@ -821,7 +1140,8 @@ main(int ac, char **av)
 				continue;
 			}
 			/* Create socket for listening. */
-			listen_sock = socket(ai->ai_family, SOCK_STREAM, 0);
+			listen_sock = socket(ai->ai_family, ai->ai_socktype,
+			    ai->ai_protocol);
 			if (listen_sock < 0) {
 				/* kernel may not support ipv6 */
 				verbose("socket: %.100s", strerror(errno));
@@ -833,25 +1153,20 @@ main(int ac, char **av)
 				continue;
 			}
 			/*
-			 * Set socket options.  We try to make the port
-			 * reusable and have it close as fast as possible
-			 * without waiting in unnecessary wait states on
-			 * close.
+			 * Set socket options.
+			 * Allow local port reuse in TIME_WAIT.
 			 */
-			setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
-			    (void *) &on, sizeof(on));
-			linger.l_onoff = 1;
-			linger.l_linger = 5;
-			setsockopt(listen_sock, SOL_SOCKET, SO_LINGER,
-			    (void *) &linger, sizeof(linger));
+			if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR,
+			    &on, sizeof(on)) == -1)
+				error("setsockopt SO_REUSEADDR: %s", strerror(errno));
 
 			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) < 0) &&
-				 (!ai->ai_next)) {
-				error("Bind to port %s on %s failed: %.200s.",
-				    strport, ntop, strerror(errno));
+			if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) {
+				if (!ai->ai_next)
+				    error("Bind to port %s on %s failed: %.200s.",
+					    strport, ntop, strerror(errno));
 				close(listen_sock);
 				continue;
 			}
@@ -859,7 +1174,7 @@ main(int ac, char **av)
 			num_listen_socks++;
 
 			/* Start listening on the port. */
-			log("Server listening on %s port %s.", ntop, strport);
+			logit("Server listening on %s port %s.", ntop, strport);
 			if (listen(listen_sock, 5) < 0)
 				fatal("listen: %.100s", strerror(errno));
 
@@ -869,6 +1184,22 @@ main(int ac, char **av)
 		if (!num_listen_socks)
 			fatal("Cannot bind any address.");
 
+		if (options.protocol & SSH_PROTO_1)
+			generate_ephemeral_server_key();
+
+		/*
+		 * Arrange to restart on SIGHUP.  The handler needs
+		 * listen_sock.
+		 */
+		signal(SIGHUP, sighup_handler);
+
+		signal(SIGTERM, sigterm_handler);
+		signal(SIGQUIT, sigterm_handler);
+
+		/* Arrange SIGCHLD to be caught. */
+		signal(SIGCHLD, main_sigchld_handler);
+
+		/* Write out the pid file after the sigterm handler is setup */
 		if (!debug_flag) {
 			/*
 			 * Record our pid in /var/run/sshd.pid to make it
@@ -878,22 +1209,14 @@ main(int ac, char **av)
 			 * overwrite any old pid in the file.
 			 */
 			f = fopen(options.pid_file, "wb");
-			if (f) {
-				fprintf(f, "%u\n", (u_int) getpid());
+			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);
 			}
 		}
-		if (options.protocol & SSH_PROTO_1)
-			generate_empheral_server_key();
-
-		/* Arrange to restart on SIGHUP.  The handler needs listen_sock. */
-		signal(SIGHUP, sighup_handler);
-
-		signal(SIGTERM, sigterm_handler);
-		signal(SIGQUIT, sigterm_handler);
-
-		/* Arrange SIGCHLD to be caught. */
-		signal(SIGCHLD, main_sigchld_handler);
 
 		/* setup fd set for listen */
 		fdset = NULL;
@@ -929,8 +1252,15 @@ main(int ac, char **av)
 			ret = select(maxfd+1, fdset, NULL, NULL, NULL);
 			if (ret < 0 && errno != EINTR)
 				error("select: %.100s", strerror(errno));
+			if (received_sigterm) {
+				logit("Received signal %d; terminating.",
+				    (int) received_sigterm);
+				close_listen_socks();
+				unlink(options.pid_file);
+				exit(255);
+			}
 			if (key_used && key_do_regen) {
-				generate_empheral_server_key();
+				generate_ephemeral_server_key();
 				key_used = 0;
 				key_do_regen = 0;
 			}
@@ -963,6 +1293,7 @@ main(int ac, char **av)
 				}
 				if (fcntl(newsock, F_SETFL, 0) < 0) {
 					error("newsock del O_NONBLOCK: %s", strerror(errno));
+					close(newsock);
 					continue;
 				}
 				if (drop_connection(startups) == 1) {
@@ -1016,9 +1347,7 @@ main(int ac, char **av)
 						 * the connection.
 						 */
 						startup_pipe = startup_p[1];
-						for (j = 0; j < options.max_startups; j++)
-							if (startup_pipes[j] != -1)
-								close(startup_pipes[j]);
+						close_startup_pipes();
 						close_listen_socks();
 						sock_in = newsock;
 						sock_out = newsock;
@@ -1031,7 +1360,7 @@ main(int ac, char **av)
 				if (pid < 0)
 					error("fork: %.100s", strerror(errno));
 				else
-					debug("Forked child %d.", pid);
+					debug("Forked child %ld.", (long)pid);
 
 				close(startup_p[1]);
 
@@ -1057,6 +1386,21 @@ main(int ac, char **av)
 
 	/* This is the child processing a new connection. */
 
+	/*
+	 * 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 !defined(SSHD_ACQUIRES_CTTY)
+	/*
+	 * If setsid is called, on some platforms sshd will later acquire a
+	 * controlling terminal which will result in "could not set
+	 * controlling tty" errors.
+	 */
+	if (!debug_flag && !inetd_flag && setsid() < 0)
+		error("setsid: %.100s", strerror(errno));
+#endif
+
 	/*
 	 * Disable the key regeneration alarm.  We will not regenerate the
 	 * key since we are no longer in a position to give it to anyone. We
@@ -1070,19 +1414,9 @@ main(int ac, char **av)
 	signal(SIGCHLD, SIG_DFL);
 	signal(SIGINT, SIG_DFL);
 
-	/*
-	 * Set socket options for the connection.  We want the socket to
-	 * close as fast as possible without waiting for anything.  If the
-	 * connection is not a socket, these will do nothing.
-	 */
-	/* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
-	linger.l_onoff = 1;
-	linger.l_linger = 5;
-	setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
-
 	/* Set keepalives if requested. */
 	if (options.keepalives &&
-	    setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
+	    setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on,
 	    sizeof(on)) < 0)
 		error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
 
@@ -1095,23 +1429,23 @@ main(int ac, char **av)
 	remote_port = get_remote_port();
 	remote_ip = get_remote_ipaddr();
 
-	/* Check whether logins are denied from this host. */
 #ifdef LIBWRAP
-	/* XXX LIBWRAP noes not know about IPv6 */
+	/* Check whether logins are denied from this host. */
 	{
 		struct request_info req;
 
-		request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, NULL);
+		request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0);
 		fromhost(&req);
 
 		if (!hosts_access(&req)) {
-			close(sock_in);
-			close(sock_out);
+			debug("Connection refused by tcp wrapper");
 			refuse(&req);
+			/* NOTREACHED */
+			fatal("libwrap refuse returns");
 		}
-/*XXX IPv6 verbose("Connection from %.500s port %d", eval_client(&req), remote_port); */
 	}
 #endif /* LIBWRAP */
+
 	/* Log the connection. */
 	verbose("Connection from %.500s port %d", remote_ip, remote_port);
 
@@ -1128,70 +1462,122 @@ main(int ac, char **av)
 		alarm(options.login_grace_time);
 
 	sshd_exchange_identification(sock_in, sock_out);
-	/*
-	 * Check that the connection comes from a privileged port.
-	 * Rhosts-Authentication only makes sense from priviledged
-	 * programs.  Of course, if the intruder has root access on his local
-	 * machine, he can connect from any port.  So do not use these
-	 * authentication methods from machines that you do not trust.
-	 */
-	if (remote_port >= IPPORT_RESERVED ||
-	    remote_port < IPPORT_RESERVED / 2) {
-		debug("Rhosts Authentication disabled, "
-		    "originating port not trusted.");
-		options.rhosts_authentication = 0;
-	}
-#ifdef KRB4
-	if (!packet_connection_is_ipv4() &&
-	    options.kerberos_authentication) {
-		debug("Kerberos Authentication disabled, only available for IPv4.");
-		options.kerberos_authentication = 0;
-	}
-#endif /* KRB4 */
 
 	packet_set_nonblocking();
 
+        /* prepare buffers to collect authentication messages */
+	buffer_init(&loginmsg);
+
+	if (use_privsep)
+		if ((authctxt = privsep_preauth()) != NULL)
+			goto authenticated;
+
 	/* perform the key exchange */
 	/* authenticate user and start session */
 	if (compat20) {
 		do_ssh2_kex();
-		do_authentication2();
+		authctxt = do_authentication2();
 	} else {
 		do_ssh1_kex();
-		do_authentication();
+		authctxt = do_authentication();
+	}
+	/*
+	 * If we use privilege separation, the unprivileged child transfers
+	 * the current keystate and exits
+	 */
+	if (use_privsep) {
+		mm_send_keystate(pmonitor);
+		exit(0);
 	}
 
-#ifdef KRB4
-	/* Cleanup user's ticket cache file. */
-	if (options.kerberos_ticket_cleanup)
-		(void) dest_tkt();
-#endif /* KRB4 */
+ authenticated:
+	/*
+	 * In privilege separation, we fork another child and prepare
+	 * file descriptor passing.
+	 */
+	if (use_privsep) {
+		privsep_postauth(authctxt);
+		/* the monitor process [priv] will not return */
+		if (!compat20)
+			destroy_sensitive_data();
+	}
+
+	/* Perform session preparation. */
+	do_authenticated(authctxt);
 
 	/* The connection has been terminated. */
 	verbose("Closing connection to %.100s", remote_ip);
 
 #ifdef USE_PAM
-	finish_pam();
+	if (options.use_pam)
+		finish_pam();
 #endif /* USE_PAM */
 
 	packet_close();
+
+	if (use_privsep)
+		mm_terminate();
+
 	exit(0);
 }
 
+/*
+ * Decrypt session_key_int using our private server key and private host key
+ * (key with larger modulus first).
+ */
+int
+ssh1_session_key(BIGNUM *session_key_int)
+{
+	int rsafail = 0;
+
+	if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
+		/* Server key has bigger modulus. */
+		if (BN_num_bits(sensitive_data.server_key->rsa->n) <
+		    BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
+			fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
+			    get_remote_ipaddr(),
+			    BN_num_bits(sensitive_data.server_key->rsa->n),
+			    BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
+			    SSH_KEY_BITS_RESERVED);
+		}
+		if (rsa_private_decrypt(session_key_int, session_key_int,
+		    sensitive_data.server_key->rsa) <= 0)
+			rsafail++;
+		if (rsa_private_decrypt(session_key_int, session_key_int,
+		    sensitive_data.ssh1_host_key->rsa) <= 0)
+			rsafail++;
+	} else {
+		/* Host key has bigger modulus (or they are equal). */
+		if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
+		    BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
+			fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
+			    get_remote_ipaddr(),
+			    BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
+			    BN_num_bits(sensitive_data.server_key->rsa->n),
+			    SSH_KEY_BITS_RESERVED);
+		}
+		if (rsa_private_decrypt(session_key_int, session_key_int,
+		    sensitive_data.ssh1_host_key->rsa) < 0)
+			rsafail++;
+		if (rsa_private_decrypt(session_key_int, session_key_int,
+		    sensitive_data.server_key->rsa) < 0)
+			rsafail++;
+	}
+	return (rsafail);
+}
 /*
  * SSH1 key exchange
  */
-void
+static void
 do_ssh1_kex(void)
 {
 	int i, len;
-	int plen, slen;
 	int rsafail = 0;
 	BIGNUM *session_key_int;
 	u_char session_key[SSH_SESSION_KEY_LENGTH];
 	u_char cookie[8];
 	u_int cipher_type, auth_mask, protocol_flags;
-	u_int32_t rand = 0;
+	u_int32_t rnd = 0;
 
 	/*
 	 * Generate check bytes that the client must send back in the user
@@ -1204,9 +1590,9 @@ do_ssh1_kex(void)
 	 */
 	for (i = 0; i < 8; i++) {
 		if (i % 4 == 0)
-			rand = arc4random();
-		cookie[i] = rand & 0xff;
-		rand >>= 8;
+			rnd = arc4random();
+		cookie[i] = rnd & 0xff;
+		rnd >>= 8;
 	}
 
 	/*
@@ -1236,23 +1622,11 @@ do_ssh1_kex(void)
 
 	/* Declare supported authentication types. */
 	auth_mask = 0;
-	if (options.rhosts_authentication)
-		auth_mask |= 1 << SSH_AUTH_RHOSTS;
 	if (options.rhosts_rsa_authentication)
 		auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
 	if (options.rsa_authentication)
 		auth_mask |= 1 << SSH_AUTH_RSA;
-#ifdef KRB4
-	if (options.kerberos_authentication)
-		auth_mask |= 1 << SSH_AUTH_KERBEROS;
-#endif
-#ifdef AFS
-	if (options.kerberos_tgt_passing)
-		auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
-	if (options.afs_token_passing)
-		auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
-#endif
-	if (options.challenge_reponse_authentication == 1)
+	if (options.challenge_response_authentication == 1)
 		auth_mask |= 1 << SSH_AUTH_TIS;
 	if (options.password_authentication)
 		auth_mask |= 1 << SSH_AUTH_PASSWORD;
@@ -1267,7 +1641,7 @@ do_ssh1_kex(void)
 	    BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
 
 	/* Read clients reply (cipher type and session key). */
-	packet_read_expect(&plen, SSH_CMSG_SESSION_KEY);
+	packet_read_expect(SSH_CMSG_SESSION_KEY);
 
 	/* Get cipher type and check whether we accept this. */
 	cipher_type = packet_get_char();
@@ -1284,58 +1658,16 @@ do_ssh1_kex(void)
 	debug("Encryption type: %.200s", cipher_name(cipher_type));
 
 	/* Get the encrypted integer. */
-	session_key_int = BN_new();
-	packet_get_bignum(session_key_int, &slen);
+	if ((session_key_int = BN_new()) == NULL)
+		fatal("do_ssh1_kex: BN_new failed");
+	packet_get_bignum(session_key_int);
 
 	protocol_flags = packet_get_int();
 	packet_set_protocol_flags(protocol_flags);
+	packet_check_eom();
 
-	packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY);
-
-	/*
-	 * Decrypt it using our private server key and private host key (key
-	 * with larger modulus first).
-	 */
-	if (BN_cmp(sensitive_data.server_key->rsa->n, sensitive_data.ssh1_host_key->rsa->n) > 0) {
-		/* Server key has bigger modulus. */
-		if (BN_num_bits(sensitive_data.server_key->rsa->n) <
-		    BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
-			fatal("do_connection: %s: server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
-			    get_remote_ipaddr(),
-			    BN_num_bits(sensitive_data.server_key->rsa->n),
-			    BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
-			    SSH_KEY_BITS_RESERVED);
-		}
-		if (rsa_private_decrypt(session_key_int, session_key_int,
-		    sensitive_data.server_key->rsa) <= 0)
-			rsafail++;
-		if (rsa_private_decrypt(session_key_int, session_key_int,
-		    sensitive_data.ssh1_host_key->rsa) <= 0)
-			rsafail++;
-	} else {
-		/* Host key has bigger modulus (or they are equal). */
-		if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) <
-		    BN_num_bits(sensitive_data.server_key->rsa->n) + SSH_KEY_BITS_RESERVED) {
-			fatal("do_connection: %s: host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d",
-			    get_remote_ipaddr(),
-			    BN_num_bits(sensitive_data.ssh1_host_key->rsa->n),
-			    BN_num_bits(sensitive_data.server_key->rsa->n),
-			    SSH_KEY_BITS_RESERVED);
-		}
-		if (rsa_private_decrypt(session_key_int, session_key_int,
-		    sensitive_data.ssh1_host_key->rsa) < 0)
-			rsafail++;
-		if (rsa_private_decrypt(session_key_int, session_key_int,
-		    sensitive_data.server_key->rsa) < 0)
-			rsafail++;
-	}
-
-	compute_session_id(session_id, cookie,
-	    sensitive_data.ssh1_host_key->rsa->n,
-	    sensitive_data.server_key->rsa->n);
-
-	/* Destroy the private and public keys.  They will no longer be needed. */
-	destroy_sensitive_data();
+	/* Decrypt session_key_int using host/server keys */
+	rsafail = PRIVSEP(ssh1_session_key(session_key_int));
 
 	/*
 	 * Extract session key from the decrypted integer.  The key is in the
@@ -1354,24 +1686,48 @@ do_ssh1_kex(void)
 			memset(session_key, 0, sizeof(session_key));
 			BN_bn2bin(session_key_int,
 			    session_key + sizeof(session_key) - len);
+
+			compute_session_id(session_id, cookie,
+			    sensitive_data.ssh1_host_key->rsa->n,
+			    sensitive_data.server_key->rsa->n);
+			/*
+			 * Xor the first 16 bytes of the session key with the
+			 * session id.
+			 */
+			for (i = 0; i < 16; i++)
+				session_key[i] ^= session_id[i];
 		}
 	}
 	if (rsafail) {
-		log("do_connection: generating a fake encryption key");
-		for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
-			if (i % 4 == 0)
-				rand = arc4random();
-			session_key[i] = rand & 0xff;
-			rand >>= 8;
-		}
+		int bytes = BN_num_bytes(session_key_int);
+		u_char *buf = xmalloc(bytes);
+		MD5_CTX md;
+
+		logit("do_connection: generating a fake encryption key");
+		BN_bn2bin(session_key_int, buf);
+		MD5_Init(&md);
+		MD5_Update(&md, buf, bytes);
+		MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
+		MD5_Final(session_key, &md);
+		MD5_Init(&md);
+		MD5_Update(&md, session_key, 16);
+		MD5_Update(&md, buf, bytes);
+		MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
+		MD5_Final(session_key + 16, &md);
+		memset(buf, 0, bytes);
+		xfree(buf);
+		for (i = 0; i < 16; i++)
+			session_id[i] = session_key[i] ^ session_key[i + 16];
 	}
+	/* Destroy the private and public keys. No longer. */
+	destroy_sensitive_data();
+
+	if (use_privsep)
+		mm_ssh1_session_id(session_id);
+
 	/* Destroy the decrypted integer.  It is no longer needed. */
 	BN_clear_free(session_key_int);
 
-	/* Xor the first 16 bytes of the session key with the session id. */
-	for (i = 0; i < 16; i++)
-		session_key[i] ^= session_id[i];
-
 	/* Set the session key.  From this on all communications will be encrypted. */
 	packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
 
@@ -1380,7 +1736,7 @@ do_ssh1_kex(void)
 
 	debug("Received session key; encryption turned on.");
 
-	/* Send an acknowledgement packet.  Note that this packet is sent encrypted. */
+	/* Send an acknowledgment packet.  Note that this packet is sent encrypted. */
 	packet_start(SSH_SMSG_SUCCESS);
 	packet_send();
 	packet_write_wait();
@@ -1389,54 +1745,46 @@ do_ssh1_kex(void)
 /*
  * SSH2 key exchange: diffie-hellman-group1-sha1
  */
-void
+static void
 do_ssh2_kex(void)
 {
-	Buffer *server_kexinit;
-	Buffer *client_kexinit;
-	int payload_len;
-	int i;
 	Kex *kex;
-	char *cprop[PROPOSAL_MAX];
-
-/* KEXINIT */
 
 	if (options.ciphers != NULL) {
 		myproposal[PROPOSAL_ENC_ALGS_CTOS] =
 		myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
 	}
+	myproposal[PROPOSAL_ENC_ALGS_CTOS] =
+	    compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
+	myproposal[PROPOSAL_ENC_ALGS_STOC] =
+	    compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
+
+	if (options.macs != NULL) {
+		myproposal[PROPOSAL_MAC_ALGS_CTOS] =
+		myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
+	}
+	if (!options.compression) {
+		myproposal[PROPOSAL_COMP_ALGS_CTOS] =
+		myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
+	}
 	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types();
 
-	server_kexinit = kex_init(myproposal);
-	client_kexinit = xmalloc(sizeof(*client_kexinit));
-	buffer_init(client_kexinit);
-
-	/* algorithm negotiation */
-	kex_exchange_kexinit(server_kexinit, client_kexinit, cprop);
-	kex = kex_choose_conf(cprop, myproposal, 1);
-	for (i = 0; i < PROPOSAL_MAX; i++)
-		xfree(cprop[i]);
+	/* start key exchange */
+	kex = kex_setup(myproposal);
+	kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server;
+	kex->kex[KEX_DH_GEX_SHA1] = kexgex_server;
+	kex->server = 1;
+	kex->client_version_string=client_version_string;
+	kex->server_version_string=server_version_string;
+	kex->load_host_key=&get_hostkey_by_type;
+	kex->host_key_index=&get_hostkey_index;
 
-	switch (kex->kex_type) {
-	case DH_GRP1_SHA1:
-		ssh_dh1_server(kex, client_kexinit, server_kexinit);
-		break;
-	case DH_GEX_SHA1:
-		ssh_dhgex_server(kex, client_kexinit, server_kexinit);
-		break;
-	default:
-		fatal("Unsupported key exchange %d", kex->kex_type);
-	}
+	xxx_kex = kex;
 
-	debug("send SSH2_MSG_NEWKEYS.");
-	packet_start(SSH2_MSG_NEWKEYS);
-	packet_send();
-	packet_write_wait();
-	debug("done: send SSH2_MSG_NEWKEYS.");
+	dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
 
-	debug("Wait SSH2_MSG_NEWKEYS.");
-	packet_read_expect(&payload_len, SSH2_MSG_NEWKEYS);
-	debug("GOT SSH2_MSG_NEWKEYS.");
+	session_id2 = kex->session_id;
+	session_id2_len = kex->session_id_len;
 
 #ifdef DEBUG_KEXDH
 	/* send 1st encrypted/maced/compressed message */
@@ -1445,285 +1793,5 @@ do_ssh2_kex(void)
 	packet_send();
 	packet_write_wait();
 #endif
-
-	debug("done: KEX2.");
-}
-
-/*
- * SSH2 key exchange
- */
-
-/* diffie-hellman-group1-sha1 */
-
-void
-ssh_dh1_server(Kex *kex, Buffer *client_kexinit, Buffer *server_kexinit)
-{
-#ifdef DEBUG_KEXDH
-	int i;
-#endif
-	int payload_len, dlen;
-	int slen;
-	u_char *signature = NULL;
-	u_char *server_host_key_blob = NULL;
-	u_int sbloblen;
-	u_int klen, kout;
-	u_char *kbuf;
-	u_char *hash;
-	BIGNUM *shared_secret = 0;
-	DH *dh;
-	BIGNUM *dh_client_pub = 0;
-	Key *hostkey;
-
-	hostkey = get_hostkey_by_type(kex->hostkey_type);
-	if (hostkey == NULL)
-		fatal("Unsupported hostkey type %d", kex->hostkey_type);
-
-/* KEXDH */
-	/* generate DH key */
-	dh = dh_new_group1();			/* XXX depends on 'kex' */
-	dh_gen_key(dh);
-
-	debug("Wait SSH2_MSG_KEXDH_INIT.");
-	packet_read_expect(&payload_len, SSH2_MSG_KEXDH_INIT);
-
-	/* key, cert */
-	dh_client_pub = BN_new();
-	if (dh_client_pub == NULL)
-		fatal("dh_client_pub == NULL");
-	packet_get_bignum2(dh_client_pub, &dlen);
-
-#ifdef DEBUG_KEXDH
-	fprintf(stderr, "\ndh_client_pub= ");
-	BN_print_fp(stderr, dh_client_pub);
-	fprintf(stderr, "\n");
-	debug("bits %d", BN_num_bits(dh_client_pub));
-#endif
-
-#ifdef DEBUG_KEXDH
-	fprintf(stderr, "\np= ");
-	BN_print_fp(stderr, dh->p);
-	fprintf(stderr, "\ng= ");
-	bn_print(dh->g);
-	fprintf(stderr, "\npub= ");
-	BN_print_fp(stderr, dh->pub_key);
-	fprintf(stderr, "\n");
-	DHparams_print_fp(stderr, dh);
-#endif
-	if (!dh_pub_is_valid(dh, dh_client_pub))
-		packet_disconnect("bad client public DH value");
-
-	klen = DH_size(dh);
-	kbuf = xmalloc(klen);
-	kout = DH_compute_key(kbuf, dh_client_pub, dh);
-
-#ifdef DEBUG_KEXDH
-	debug("shared secret: len %d/%d", klen, kout);
-	fprintf(stderr, "shared secret == ");
-	for (i = 0; i< kout; i++)
-		fprintf(stderr, "%02x", (kbuf[i])&0xff);
-	fprintf(stderr, "\n");
-#endif
-	shared_secret = BN_new();
-
-	BN_bin2bn(kbuf, kout, shared_secret);
-	memset(kbuf, 0, klen);
-	xfree(kbuf);
-
-	/* XXX precompute? */
-	key_to_blob(hostkey, &server_host_key_blob, &sbloblen);
-
-	/* calc H */			/* XXX depends on 'kex' */
-	hash = kex_hash(
-	    client_version_string,
-	    server_version_string,
-	    buffer_ptr(client_kexinit), buffer_len(client_kexinit),
-	    buffer_ptr(server_kexinit), buffer_len(server_kexinit),
-	    (char *)server_host_key_blob, sbloblen,
-	    dh_client_pub,
-	    dh->pub_key,
-	    shared_secret
-	);
-	buffer_free(client_kexinit);
-	buffer_free(server_kexinit);
-	xfree(client_kexinit);
-	xfree(server_kexinit);
-	BN_free(dh_client_pub);
-#ifdef DEBUG_KEXDH
-	fprintf(stderr, "hash == ");
-	for (i = 0; i< 20; i++)
-		fprintf(stderr, "%02x", (hash[i])&0xff);
-	fprintf(stderr, "\n");
-#endif
-	/* save session id := H */
-	/* XXX hashlen depends on KEX */
-	session_id2_len = 20;
-	session_id2 = xmalloc(session_id2_len);
-	memcpy(session_id2, hash, session_id2_len);
-
-	/* sign H */
-	/* XXX hashlen depends on KEX */
-	key_sign(hostkey, &signature, &slen, hash, 20);
-
-	destroy_sensitive_data();
-
-	/* send server hostkey, DH pubkey 'f' and singed H */
-	packet_start(SSH2_MSG_KEXDH_REPLY);
-	packet_put_string((char *)server_host_key_blob, sbloblen);
-	packet_put_bignum2(dh->pub_key);	/* f */
-	packet_put_string((char *)signature, slen);
-	packet_send();
-	xfree(signature);
-	xfree(server_host_key_blob);
-	packet_write_wait();
-
-	kex_derive_keys(kex, hash, shared_secret);
-	BN_clear_free(shared_secret);
-	packet_set_kex(kex);
-
-	/* have keys, free DH */
-	DH_free(dh);
-}
-
-/* diffie-hellman-group-exchange-sha1 */
-
-void
-ssh_dhgex_server(Kex *kex, Buffer *client_kexinit, Buffer *server_kexinit)
-{
-#ifdef DEBUG_KEXDH
-	int i;
-#endif
-	int payload_len, dlen;
-	int slen, nbits;
-	u_char *signature = NULL;
-	u_char *server_host_key_blob = NULL;
-	u_int sbloblen;
-	u_int klen, kout;
-	u_char *kbuf;
-	u_char *hash;
-	BIGNUM *shared_secret = 0;
-	DH *dh;
-	BIGNUM *dh_client_pub = 0;
-	Key *hostkey;
-
-	hostkey = get_hostkey_by_type(kex->hostkey_type);
-	if (hostkey == NULL)
-		fatal("Unsupported hostkey type %d", kex->hostkey_type);
-
-/* KEXDHGEX */
-	debug("Wait SSH2_MSG_KEX_DH_GEX_REQUEST.");
-	packet_read_expect(&payload_len, SSH2_MSG_KEX_DH_GEX_REQUEST);
-	nbits = packet_get_int();
-	dh = choose_dh(nbits);
-
-	debug("Sending SSH2_MSG_KEX_DH_GEX_GROUP.");
-	packet_start(SSH2_MSG_KEX_DH_GEX_GROUP);
-	packet_put_bignum2(dh->p);
-	packet_put_bignum2(dh->g);
-	packet_send();
-	packet_write_wait();
-
-	/* Compute our exchange value in parallel with the client */
-
-	dh_gen_key(dh);
-
-	debug("Wait SSH2_MSG_KEX_DH_GEX_INIT.");
-	packet_read_expect(&payload_len, SSH2_MSG_KEX_DH_GEX_INIT);
-
-	/* key, cert */
-	dh_client_pub = BN_new();
-	if (dh_client_pub == NULL)
-		fatal("dh_client_pub == NULL");
-	packet_get_bignum2(dh_client_pub, &dlen);
-
-#ifdef DEBUG_KEXDH
-	fprintf(stderr, "\ndh_client_pub= ");
-	BN_print_fp(stderr, dh_client_pub);
-	fprintf(stderr, "\n");
-	debug("bits %d", BN_num_bits(dh_client_pub));
-#endif
-
-#ifdef DEBUG_KEXDH
-	fprintf(stderr, "\np= ");
-	BN_print_fp(stderr, dh->p);
-	fprintf(stderr, "\ng= ");
-	bn_print(dh->g);
-	fprintf(stderr, "\npub= ");
-	BN_print_fp(stderr, dh->pub_key);
-	fprintf(stderr, "\n");
-	DHparams_print_fp(stderr, dh);
-#endif
-	if (!dh_pub_is_valid(dh, dh_client_pub))
-		packet_disconnect("bad client public DH value");
-
-	klen = DH_size(dh);
-	kbuf = xmalloc(klen);
-	kout = DH_compute_key(kbuf, dh_client_pub, dh);
-
-#ifdef DEBUG_KEXDH
-	debug("shared secret: len %d/%d", klen, kout);
-	fprintf(stderr, "shared secret == ");
-	for (i = 0; i< kout; i++)
-		fprintf(stderr, "%02x", (kbuf[i])&0xff);
-	fprintf(stderr, "\n");
-#endif
-	shared_secret = BN_new();
-
-	BN_bin2bn(kbuf, kout, shared_secret);
-	memset(kbuf, 0, klen);
-	xfree(kbuf);
-
-	/* XXX precompute? */
-	key_to_blob(hostkey, &server_host_key_blob, &sbloblen);
-
-	/* calc H */			/* XXX depends on 'kex' */
-	hash = kex_hash_gex(
-	    client_version_string,
-	    server_version_string,
-	    buffer_ptr(client_kexinit), buffer_len(client_kexinit),
-	    buffer_ptr(server_kexinit), buffer_len(server_kexinit),
-	    (char *)server_host_key_blob, sbloblen,
-	    nbits, dh->p, dh->g,
-	    dh_client_pub,
-	    dh->pub_key,
-	    shared_secret
-	);
-	buffer_free(client_kexinit);
-	buffer_free(server_kexinit);
-	xfree(client_kexinit);
-	xfree(server_kexinit);
-	BN_free(dh_client_pub);
-#ifdef DEBUG_KEXDH
-	fprintf(stderr, "hash == ");
-	for (i = 0; i< 20; i++)
-		fprintf(stderr, "%02x", (hash[i])&0xff);
-	fprintf(stderr, "\n");
-#endif
-	/* save session id := H */
-	/* XXX hashlen depends on KEX */
-	session_id2_len = 20;
-	session_id2 = xmalloc(session_id2_len);
-	memcpy(session_id2, hash, session_id2_len);
-
-	/* sign H */
-	/* XXX hashlen depends on KEX */
-	key_sign(hostkey, &signature, &slen, hash, 20);
-
-	destroy_sensitive_data();
-
-	/* send server hostkey, DH pubkey 'f' and singed H */
-	packet_start(SSH2_MSG_KEX_DH_GEX_REPLY);
-	packet_put_string((char *)server_host_key_blob, sbloblen);
-	packet_put_bignum2(dh->pub_key);	/* f */
-	packet_put_string((char *)signature, slen);
-	packet_send();
-	xfree(signature);
-	xfree(server_host_key_blob);
-	packet_write_wait();
-
-	kex_derive_keys(kex, hash, shared_secret);
-	BN_clear_free(shared_secret);
-	packet_set_kex(kex);
-
-	/* have keys, free DH */
-	DH_free(dh);
+	debug("KEX done");
 }