X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/8abcdba4e06cabbda1d9f8a42ed58a81336819cd..7caca6d44d365220a637081df8cce38c5d26c588:/sshconnect.c

diff --git a/sshconnect.c b/sshconnect.c
index 22e69142..40d22800 100644
--- a/sshconnect.c
+++ b/sshconnect.c
@@ -13,36 +13,55 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshconnect.c,v 1.87 2000/12/28 14:25:03 markus Exp $");
+RCSID("$OpenBSD: sshconnect.c,v 1.147 2003/06/29 12:44:38 markus Exp $");
 
 #include <openssl/bn.h>
-#include <openssl/dsa.h>
-#include <openssl/rsa.h>
 
+#include "ssh.h"
 #include "xmalloc.h"
 #include "rsa.h"
-#include "ssh.h"
 #include "buffer.h"
 #include "packet.h"
 #include "uidswap.h"
 #include "compat.h"
-#include "readconf.h"
 #include "key.h"
 #include "sshconnect.h"
 #include "hostfile.h"
+#include "log.h"
+#include "readconf.h"
+#include "atomicio.h"
+#include "misc.h"
+#include "readpass.h"
+
+#ifdef DNS
+#include "dns.h"
+#endif
 
 char *client_version_string = NULL;
 char *server_version_string = NULL;
 
+#ifdef DNS
+int verified_host_key_dns = 0;
+#endif
+
+/* import */
 extern Options options;
 extern char *__progname;
+extern uid_t original_real_uid;
+extern uid_t original_effective_uid;
+extern pid_t proxy_command_pid;
+
+#ifndef INET6_ADDRSTRLEN		/* for non IPv6 machines */
+#define INET6_ADDRSTRLEN 46
+#endif
+
+static int show_other_keys(const char *, Key *);
 
 /*
  * Connect to the given ssh server using a proxy command.
  */
-int
-ssh_proxy_connect(const char *host, u_short port, uid_t original_real_uid,
-		  const char *proxy_command)
+static int
+ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
 {
 	Buffer command;
 	const char *cp;
@@ -54,9 +73,16 @@ ssh_proxy_connect(const char *host, u_short port, uid_t original_real_uid,
 	/* Convert the port number into a string. */
 	snprintf(strport, sizeof strport, "%hu", port);
 
-	/* Build the final command string in the buffer by making the
-	   appropriate substitutions to the given proxy command. */
+	/*
+	 * Build the final command string in the buffer by making the
+	 * appropriate substitutions to the given proxy command.
+	 *
+	 * Use "exec" to avoid "sh -c" processes on some platforms 
+	 * (e.g. Solaris)
+	 */
 	buffer_init(&command);
+	buffer_append(&command, "exec ", 5);
+
 	for (cp = proxy_command; *cp; cp++) {
 		if (cp[0] == '%' && cp[1] == '%') {
 			buffer_append(&command, "%", 1);
@@ -83,7 +109,7 @@ ssh_proxy_connect(const char *host, u_short port, uid_t original_real_uid,
 	/* Create pipes for communicating with the proxy. */
 	if (pipe(pin) < 0 || pipe(pout) < 0)
 		fatal("Could not create pipes to communicate with the proxy: %.100s",
-		      strerror(errno));
+		    strerror(errno));
 
 	debug("Executing proxy command: %.500s", command_string);
 
@@ -92,7 +118,8 @@ ssh_proxy_connect(const char *host, u_short port, uid_t original_real_uid,
 		char *argv[10];
 
 		/* Child.  Permanently give up superuser privileges. */
-		permanently_set_uid(original_real_uid);
+		seteuid(original_real_uid);
+		setuid(original_real_uid);
 
 		/* Redirect stdin and stdout. */
 		close(pin[1]);
@@ -116,13 +143,15 @@ ssh_proxy_connect(const char *host, u_short port, uid_t original_real_uid,
 
 		/* Execute the proxy command.  Note that we gave up any
 		   extra privileges above. */
-		execv(_PATH_BSHELL, argv);
-		perror(_PATH_BSHELL);
+		execv(argv[0], argv);
+		perror(argv[0]);
 		exit(1);
 	}
 	/* Parent. */
 	if (pid < 0)
 		fatal("fork failed: %.100s", strerror(errno));
+	else
+		proxy_command_pid = pid; /* save pid to clean up later */
 
 	/* Close child side of the descriptors. */
 	close(pin[0]);
@@ -134,16 +163,18 @@ ssh_proxy_connect(const char *host, u_short port, uid_t original_real_uid,
 	/* Set the connection file descriptors. */
 	packet_set_connection(pout[0], pin[1]);
 
-	return 1;
+	/* Indicate OK return */
+	return 0;
 }
 
 /*
  * Creates a (possibly privileged) socket for use as the ssh connection.
  */
-int
-ssh_create_socket(uid_t original_real_uid, int privileged, int family)
+static int
+ssh_create_socket(int privileged, struct addrinfo *ai)
 {
-	int sock;
+	int sock, gaierr;
+	struct addrinfo hints, *res;
 
 	/*
 	 * If we are running as root and want to connect to a privileged
@@ -151,51 +182,149 @@ ssh_create_socket(uid_t original_real_uid, int privileged, int family)
 	 */
 	if (privileged) {
 		int p = IPPORT_RESERVED - 1;
-		sock = rresvport_af(&p, family);
+		PRIV_START;
+		sock = rresvport_af(&p, ai->ai_family);
+		PRIV_END;
 		if (sock < 0)
-			error("rresvport: af=%d %.100s", family, strerror(errno));
+			error("rresvport: af=%d %.100s", ai->ai_family,
+			    strerror(errno));
 		else
 			debug("Allocated local port %d.", p);
-	} else {
-		/*
-		 * Just create an ordinary socket on arbitrary port.  We use
-		 * the user's uid to create the socket.
-		 */
-		temporarily_use_uid(original_real_uid);
-		sock = socket(family, SOCK_STREAM, 0);
-		if (sock < 0)
-			error("socket: %.100s", strerror(errno));
-		restore_uid();
+		return sock;
+	}
+	sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+	if (sock < 0)
+		error("socket: %.100s", strerror(errno));
+
+	/* Bind the socket to an alternative local IP address */
+	if (options.bind_address == NULL)
+		return sock;
+
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = ai->ai_family;
+	hints.ai_socktype = ai->ai_socktype;
+	hints.ai_protocol = ai->ai_protocol;
+	hints.ai_flags = AI_PASSIVE;
+	gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
+	if (gaierr) {
+		error("getaddrinfo: %s: %s", options.bind_address,
+		    gai_strerror(gaierr));
+		close(sock);
+		return -1;
+	}
+	if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
+		error("bind: %s: %s", options.bind_address, strerror(errno));
+		close(sock);
+		freeaddrinfo(res);
+		return -1;
 	}
+	freeaddrinfo(res);
 	return sock;
 }
 
+static int
+timeout_connect(int sockfd, const struct sockaddr *serv_addr,
+    socklen_t addrlen, int timeout)
+{
+	fd_set *fdset;
+	struct timeval tv;
+	socklen_t optlen;
+	int fdsetsz, optval, rc, result = -1;
+
+	if (timeout <= 0)
+		return (connect(sockfd, serv_addr, addrlen));
+
+	if (fcntl(sockfd, F_SETFL, O_NONBLOCK) < 0)
+		return (-1);
+
+	rc = connect(sockfd, serv_addr, addrlen);
+	if (rc == 0)
+		return (0);
+	if (errno != EINPROGRESS)
+		return (-1);
+
+	fdsetsz = howmany(sockfd + 1, NFDBITS) * sizeof(fd_mask);
+	fdset = (fd_set *)xmalloc(fdsetsz);
+
+	memset(fdset, 0, fdsetsz);
+	FD_SET(sockfd, fdset);
+	tv.tv_sec = timeout;
+	tv.tv_usec = 0;
+
+	for(;;) {
+		rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
+		if (rc != -1 || errno != EINTR)
+			break;
+	}
+
+	switch(rc) {
+	case 0:
+		/* Timed out */
+		errno = ETIMEDOUT;
+		break;
+	case -1:
+		/* Select error */
+	    	debug("select: %s", strerror(errno));
+		break;
+	case 1:
+		/* Completed or failed */
+		optval = 0;
+		optlen = sizeof(optval);
+		if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, 
+		    &optlen) == -1)
+		    	debug("getsockopt: %s", strerror(errno));
+			break;
+		if (optval != 0) {
+			errno = optval;
+			break;
+		}
+		result = 0;
+		break;
+	default:
+		/* Should not occur */
+		fatal("Bogus return (%d) from select()", rc);
+	}
+
+	xfree(fdset);
+	return (result);
+}
+
 /*
  * Opens a TCP/IP connection to the remote server on the given host.
  * The address of the remote host will be returned in hostaddr.
- * If port is 0, the default port will be used.  If anonymous is zero,
+ * If port is 0, the default port will be used.  If needpriv is true,
  * a privileged port will be allocated to make the connection.
- * This requires super-user privileges if anonymous is false.
+ * This requires super-user privileges if needpriv is true.
  * Connection_attempts specifies the maximum number of tries (one per
  * second).  If proxy_command is non-NULL, it specifies the command (with %h
  * and %p substituted for host and port, respectively) to use to contact
  * the daemon.
+ * Return values:
+ *    0 for OK
+ *    ECONNREFUSED if we got a "Connection Refused" by the peer on any address
+ *    ECONNABORTED if we failed without a "Connection refused"
+ * Suitable error messages for the connection failure will already have been
+ * printed.
  */
 int
 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
-	    u_short port, int connection_attempts,
-	    int anonymous, uid_t original_real_uid,
-	    const char *proxy_command)
+    u_short port, int family, int connection_attempts,
+    int needpriv, const char *proxy_command)
 {
+	int gaierr;
+	int on = 1;
 	int sock = -1, attempt;
-	struct servent *sp;
-	struct addrinfo hints, *ai, *aitop;
 	char ntop[NI_MAXHOST], strport[NI_MAXSERV];
-	int gaierr;
-	struct linger linger;
+	struct addrinfo hints, *ai, *aitop;
+	struct servent *sp;
+	/*
+	 * Did we get only other errors than "Connection refused" (which
+	 * should block fallback to rsh and similar), or did we get at least
+	 * one "Connection refused"?
+	 */
+	int full_failure = 1;
 
-	debug("ssh_connect: getuid %u geteuid %u anon %d",
-	      (u_int) getuid(), (u_int) geteuid(), anonymous);
+	debug2("ssh_connect: needpriv %d", needpriv);
 
 	/* Get default port if port has not been set. */
 	if (port == 0) {
@@ -207,14 +336,14 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
 	}
 	/* If a proxy command is given, connect using it. */
 	if (proxy_command != NULL)
-		return ssh_proxy_connect(host, port, original_real_uid, proxy_command);
+		return ssh_proxy_connect(host, port, proxy_command);
 
 	/* No proxy command. */
 
 	memset(&hints, 0, sizeof(hints));
-	hints.ai_family = IPv4or6;
+	hints.ai_family = family;
 	hints.ai_socktype = SOCK_STREAM;
-	snprintf(strport, sizeof strport, "%d", port);
+	snprintf(strport, sizeof strport, "%u", port);
 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
 		fatal("%s: %.100s: %s", __progname, host,
 		    gai_strerror(gaierr));
@@ -223,8 +352,8 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
 	 * Try to connect several times.  On some machines, the first time
 	 * will sometimes fail.  In general socket code appears to behave
 	 * quite magically on many machines.
-	 */
-	for (attempt = 0; attempt < connection_attempts; attempt++) {
+		 */
+	for (attempt = 0; ;) {
 		if (attempt > 0)
 			debug("Trying again...");
 
@@ -243,42 +372,36 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
 				host, ntop, strport);
 
 			/* Create a socket for connecting. */
-			sock = ssh_create_socket(original_real_uid,
-#ifdef HAVE_CYGWIN
-			    !anonymous,
-#else
-			    !anonymous && geteuid() == 0,
-#endif
-			    ai->ai_family);
+			sock = ssh_create_socket(needpriv, ai);
 			if (sock < 0)
+				/* Any error is already output */
 				continue;
 
-			/* Connect to the host.  We use the user's uid in the
-			 * hope that it will help with tcp_wrappers showing
-			 * the remote uid as root.
-			 */
-			temporarily_use_uid(original_real_uid);
-			if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) {
+			if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
+			    options.connection_timeout) >= 0) {
 				/* Successful connection. */
 				memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
-				restore_uid();
 				break;
 			} else {
-				debug("connect: %.100s", strerror(errno));
-				restore_uid();
+				if (errno == ECONNREFUSED)
+					full_failure = 0;
+				debug("connect to address %s port %s: %s",
+				    ntop, strport, strerror(errno));
 				/*
 				 * Close the failed socket; there appear to
 				 * be some problems when reusing a socket for
 				 * which connect() has already returned an
 				 * error.
 				 */
-				shutdown(sock, SHUT_RDWR);
 				close(sock);
 			}
 		}
 		if (ai)
 			break;	/* Successful connection. */
 
+		attempt++;
+		if (attempt >= connection_attempts)
+			break;
 		/* Sleep a moment before retrying. */
 		sleep(1);
 	}
@@ -286,38 +409,38 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
 	freeaddrinfo(aitop);
 
 	/* Return failure if we didn't get a successful connection. */
-	if (attempt >= connection_attempts)
-		return 0;
+	if (attempt >= connection_attempts) {
+		logit("ssh: connect to host %s port %s: %s",
+		    host, strport, strerror(errno));
+		return full_failure ? ECONNABORTED : ECONNREFUSED;
+	}
 
 	debug("Connection established.");
 
-	/*
-	 * Set socket options.  We would like the socket to disappear as soon
-	 * as it has been closed for whatever reason.
-	 */
-	/* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
-	linger.l_onoff = 1;
-	linger.l_linger = 5;
-	setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
+	/* Set keepalives if requested. */
+	if (options.keepalives &&
+	    setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
+	    sizeof(on)) < 0)
+		error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
 
 	/* Set the connection. */
 	packet_set_connection(sock, sock);
 
-	return 1;
+	return 0;
 }
 
 /*
  * Waits for the server identification string, and sends our own
  * identification string.
  */
-void
-ssh_exchange_identification()
+static void
+ssh_exchange_identification(void)
 {
 	char buf[256], remote_version[256];	/* must be same size! */
 	int remote_major, remote_minor, i, mismatch;
 	int connection_in = packet_get_connection_in();
 	int connection_out = packet_get_connection_out();
-	int minor1 = PROTOCOL_MINOR_1; 
+	int minor1 = PROTOCOL_MINOR_1;
 
 	/* Read other side\'s version identification. */
 	for (;;) {
@@ -352,12 +475,12 @@ ssh_exchange_identification()
 	    &remote_major, &remote_minor, remote_version) != 3)
 		fatal("Bad remote protocol version identification: '%.100s'", buf);
 	debug("Remote protocol version %d.%d, remote software version %.100s",
-	      remote_major, remote_minor, remote_version);
+	    remote_major, remote_minor, remote_version);
 
 	compat_datafellows(remote_version);
 	mismatch = 0;
 
-	switch(remote_major) {
+	switch (remote_major) {
 	case 1:
 		if (remote_minor == 99 &&
 		    (options.protocol & SSH_PROTO_2) &&
@@ -376,7 +499,7 @@ ssh_exchange_identification()
 			enable_compat13();
 			minor1 = 3;
 			if (options.forward_agent) {
-				log("Agent forwarding disabled for protocol 1.3");
+				logit("Agent forwarding disabled for protocol 1.3");
 				options.forward_agent = 0;
 			}
 		}
@@ -395,14 +518,12 @@ ssh_exchange_identification()
 		fatal("Protocol major versions differ: %d vs. %d",
 		    (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
 		    remote_major);
-	if (compat20)
-		packet_set_ssh2_format();
 	/* Send our own protocol version identification. */
 	snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
 	    compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
 	    compat20 ? PROTOCOL_MINOR_2 : minor1,
 	    SSH_VERSION);
-	if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf))
+	if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf))
 		fatal("write: %.100s", strerror(errno));
 	client_version_string = xstrdup(buf);
 	chop(client_version_string);
@@ -410,69 +531,50 @@ ssh_exchange_identification()
 	debug("Local version string %.100s", client_version_string);
 }
 
-int
-read_yes_or_no(const char *prompt, int defval)
+/* defaults to 'no' */
+static int
+confirm(const char *prompt)
 {
-	char buf[1024];
-	FILE *f;
-	int retval = -1;
+	const char *msg, *again = "Please type 'yes' or 'no': ";
+	char *p;
+	int ret = -1;
 
-	if (isatty(0))
-		f = stdin;
-	else
-		f = fopen("/dev/tty", "rw");
-
-	if (f == NULL)
+	if (options.batch_mode)
 		return 0;
-
-	fflush(stdout);
-
-	while (1) {
-		fprintf(stderr, "%s", prompt);
-		if (fgets(buf, sizeof(buf), f) == NULL) {
-			/* Print a newline (the prompt probably didn\'t have one). */
-			fprintf(stderr, "\n");
-			strlcpy(buf, "no", sizeof buf);
-		}
-		/* Remove newline from response. */
-		if (strchr(buf, '\n'))
-			*strchr(buf, '\n') = 0;
-
-		if (buf[0] == 0)
-			retval = defval;
-		if (strcmp(buf, "yes") == 0)
-			retval = 1;
-		else if (strcmp(buf, "no") == 0)
-			retval = 0;
-		else
-			fprintf(stderr, "Please type 'yes' or 'no'.\n");
-
-		if (retval != -1) {
-			if (f != stdin)
-				fclose(f);
-			return retval;
-		}
+	for (msg = prompt;;msg = again) {
+		p = read_passphrase(msg, RP_ECHO);
+		if (p == NULL ||
+		    (p[0] == '\0') || (p[0] == '\n') ||
+		    strncasecmp(p, "no", 2) == 0)
+			ret = 0;
+		if (p && strncasecmp(p, "yes", 3) == 0)
+			ret = 1;
+		if (p)
+			xfree(p);
+		if (ret != -1)
+			return ret;
 	}
 }
 
 /*
- * check whether the supplied host key is valid, return only if ok.
+ * check whether the supplied host key is valid, return -1 if the key
+ * is not valid. the user_hostfile will not be updated if 'readonly' is true.
  */
-
-void
+static int
 check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
-	const char *user_hostfile, const char *system_hostfile)
+    int readonly, const char *user_hostfile, const char *system_hostfile)
 {
 	Key *file_key;
 	char *type = key_type(host_key);
 	char *ip = NULL;
-	char hostline[1000], *hostp;
+	char hostline[1000], *hostp, *fp;
 	HostStatus host_status;
 	HostStatus ip_status;
 	int local = 0, host_ip_differ = 0;
 	int salen;
 	char ntop[NI_MAXHOST];
-	int host_line = -1, ip_line = -1;
+	char msg[1024];
+	int len, host_line, ip_line;
 	const char *host_file = NULL, *ip_file = NULL;
 
 	/*
@@ -486,11 +588,13 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 	/**  hostaddr == 0! */
 	switch (hostaddr->sa_family) {
 	case AF_INET:
-		local = (ntohl(((struct sockaddr_in *)hostaddr)->sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
+		local = (ntohl(((struct sockaddr_in *)hostaddr)->
+		   sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
 		salen = sizeof(struct sockaddr_in);
 		break;
 	case AF_INET6:
-		local = IN6_IS_ADDR_LOOPBACK(&(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
+		local = IN6_IS_ADDR_LOOPBACK(
+		    &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
 		salen = sizeof(struct sockaddr_in6);
 		break;
 	default:
@@ -498,38 +602,37 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 		salen = sizeof(struct sockaddr_storage);
 		break;
 	}
-	if (local) {
-		if (options.host_key_alias == NULL) {
-			debug("Forcing accepting of host key for "
-			    "loopback/localhost.");
-			return;
-		}
-		if (options.check_host_ip)
-			options.check_host_ip = 0;
+	if (options.no_host_authentication_for_localhost == 1 && local &&
+	    options.host_key_alias == NULL) {
+		debug("Forcing accepting of host key for "
+		    "loopback/localhost.");
+		return 0;
 	}
 
 	/*
-	 * Turn off check_host_ip for proxy connects, since
-	 * we don't have the remote ip-address
+	 * We don't have the remote ip-address for connections
+	 * using a proxy command
 	 */
-	if (options.proxy_command != NULL && options.check_host_ip)
+	if (options.proxy_command == NULL) {
+		if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
+		    NULL, 0, NI_NUMERICHOST) != 0)
+			fatal("check_host_key: getnameinfo failed");
+		ip = xstrdup(ntop);
+	} else {
+		ip = xstrdup("<no hostip for proxy command>");
+	}
+	/*
+	 * Turn off check_host_ip if the connection is to localhost, via proxy
+	 * command or if we don't have a hostname to compare with
+	 */
+	if (options.check_host_ip &&
+	    (local || strcmp(host, ip) == 0 || options.proxy_command != NULL))
 		options.check_host_ip = 0;
 
-
-
- 	if (options.proxy_command == NULL) {
- 		if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
- 		    NULL, 0, NI_NUMERICHOST) != 0)
- 			fatal("check_host_key: getnameinfo failed");
- 		ip = xstrdup(ntop);
- 	} else {
- 		ip = xstrdup("<no hostip for proxy command>");
- 	}
-
 	/*
-  	 * Allow the user to record the key under a different name. This is
+	 * Allow the user to record the key under a different name. This is
 	 * useful for ssh tunneling over forwarded connections or if you run
-         * multiple sshd's on different ports on the same machine.
+	 * multiple sshd's on different ports on the same machine.
 	 */
 	if (options.host_key_alias != NULL) {
 		host = options.host_key_alias;
@@ -547,23 +650,27 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 	 * hosts or in the systemwide list.
 	 */
 	host_file = user_hostfile;
-	host_status = check_host_in_hostfile(host_file, host, host_key, file_key, &host_line);
+	host_status = check_host_in_hostfile(host_file, host, host_key,
+	    file_key, &host_line);
 	if (host_status == HOST_NEW) {
 		host_file = system_hostfile;
-		host_status = check_host_in_hostfile(host_file, host, host_key, file_key, &host_line);
+		host_status = check_host_in_hostfile(host_file, host, host_key,
+		    file_key, &host_line);
 	}
 	/*
 	 * Also perform check for the ip address, skip the check if we are
 	 * localhost or the hostname was an ip address to begin with
 	 */
-	if (options.check_host_ip && !local && strcmp(host, ip)) {
+	if (options.check_host_ip) {
 		Key *ip_key = key_new(host_key->type);
 
 		ip_file = user_hostfile;
-		ip_status = check_host_in_hostfile(ip_file, ip, host_key, ip_key, &ip_line);
+		ip_status = check_host_in_hostfile(ip_file, ip, host_key,
+		    ip_key, &ip_line);
 		if (ip_status == HOST_NEW) {
 			ip_file = system_hostfile;
-			ip_status = check_host_in_hostfile(ip_file, ip, host_key, ip_key, &ip_line);
+			ip_status = check_host_in_hostfile(ip_file, ip,
+			    host_key, ip_key, &ip_line);
 		}
 		if (host_status == HOST_CHANGED &&
 		    (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
@@ -581,53 +688,86 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 		debug("Host '%.200s' is known and matches the %s host key.",
 		    host, type);
 		debug("Found key in %s:%d", host_file, host_line);
-		if (options.check_host_ip) {
-			if (ip_status == HOST_NEW) {
-				if (!add_host_to_hostfile(user_hostfile, ip, host_key))
-					log("Failed to add the %s host key for IP address '%.30s' to the list of known hosts (%.30s).",
-					    type, ip, user_hostfile);
-				else
-					log("Warning: Permanently added the %s host key for IP address '%.30s' to the list of known hosts.",
-					    type, ip);
-			} else if (ip_status != HOST_OK) {
-				log("Warning: the %s host key for '%.200s' differs from the key for the IP address '%.30s'",
-				    type, host, ip);
-				log("Found key in %s:%d", host_file, host_line);
-				if (ip_line != -1)
-					log("Offending key for IP in %s:%d", ip_file, ip_line);
-			}
+		if (options.check_host_ip && ip_status == HOST_NEW) {
+			if (readonly)
+				logit("%s host key for IP address "
+				    "'%.128s' not in list of known hosts.",
+				    type, ip);
+			else if (!add_host_to_hostfile(user_hostfile, ip,
+			    host_key))
+				logit("Failed to add the %s host key for IP "
+				    "address '%.128s' to the list of known "
+				    "hosts (%.30s).", type, ip, user_hostfile);
+			else
+				logit("Warning: Permanently added the %s host "
+				    "key for IP address '%.128s' to the list "
+				    "of known hosts.", type, ip);
 		}
 		break;
 	case HOST_NEW:
+		if (readonly)
+			goto fail;
 		/* The host is new. */
 		if (options.strict_host_key_checking == 1) {
-			/* User has requested strict host key checking.  We will not add the host key
-			   automatically.  The only alternative left is to abort. */
-			fatal("No %s host key is known for %.200s and you have requested strict checking.", type, host);
+			/*
+			 * User has requested strict host key checking.  We
+			 * will not add the host key automatically.  The only
+			 * alternative left is to abort.
+			 */
+			error("No %s host key is known for %.200s and you "
+			    "have requested strict checking.", type, host);
+			goto fail;
 		} else if (options.strict_host_key_checking == 2) {
+			char msg1[1024], msg2[1024];
+
+			if (show_other_keys(host, host_key))
+				snprintf(msg1, sizeof(msg1),
+				   "\nbut keys of different type are already"
+				   " known for this host.");
+			else
+				snprintf(msg1, sizeof(msg1), ".");
 			/* The default */
-			char prompt[1024];
-			snprintf(prompt, sizeof(prompt),
-			    "The authenticity of host '%.200s (%s)' can't be established.\n"
-			    "%s key fingerprint is %s.\n"
-			    "Are you sure you want to continue connecting (yes/no)? ",
-			    host, ip, type, key_fingerprint(host_key));
-			if (!read_yes_or_no(prompt, -1))
-				fatal("Aborted by user!\n");
+			fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
+			msg2[0] = '\0';
+#ifdef DNS
+			if (options.verify_host_key_dns) {
+				if (verified_host_key_dns)
+					snprintf(msg2, sizeof(msg2),
+					    "Matching host key fingerprint"
+					    " found in DNS.\n");
+				else
+					snprintf(msg2, sizeof(msg2),
+					    "No matching host key fingerprint"
+					    " found in DNS.\n");
+			}
+#endif
+			snprintf(msg, sizeof(msg),
+			    "The authenticity of host '%.200s (%s)' can't be "
+			    "established%s\n"
+			    "%s key fingerprint is %s.\n%s"
+			    "Are you sure you want to continue connecting "
+			    "(yes/no)? ",
+			    host, ip, msg1, type, fp, msg2);
+			xfree(fp);
+			if (!confirm(msg))
+				goto fail;
 		}
-		if (options.check_host_ip && ip_status == HOST_NEW && strcmp(host, ip)) {
+		if (options.check_host_ip && ip_status == HOST_NEW) {
 			snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
 			hostp = hostline;
 		} else
 			hostp = host;
 
-		/* If not in strict mode, add the key automatically to the local known_hosts file. */
+		/*
+		 * If not in strict mode, add the key automatically to the
+		 * local known_hosts file.
+		 */
 		if (!add_host_to_hostfile(user_hostfile, hostp, host_key))
-			log("Failed to add the host to the list of known hosts (%.500s).",
-			    user_hostfile);
+			logit("Failed to add the host to the list of known "
+			    "hosts (%.500s).", user_hostfile);
 		else
-			log("Warning: Permanently added '%.200s' (%s) to the list of known hosts.",
-			    hostp, type);
+			logit("Warning: Permanently added '%.200s' (%s) to the "
+			    "list of known hosts.", hostp, type);
 		break;
 	case HOST_CHANGED:
 		if (options.check_host_ip && host_ip_differ) {
@@ -646,10 +786,11 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 			error("%s. This could either mean that", msg);
 			error("DNS SPOOFING is happening or the IP address for the host");
 			error("and its host key have changed at the same time.");
-			if (ip_line != -1)
+			if (ip_status != HOST_NEW)
 				error("Offending key for IP in %s:%d", ip_file, ip_line);
 		}
 		/* The host key has changed. */
+		fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
 		error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
 		error("@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @");
 		error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
@@ -657,39 +798,60 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 		error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
 		error("It is also possible that the %s host key has just been changed.", type);
 		error("The fingerprint for the %s key sent by the remote host is\n%s.",
-		    type, key_fingerprint(host_key));
+		    type, fp);
 		error("Please contact your system administrator.");
 		error("Add correct host key in %.100s to get rid of this message.",
 		    user_hostfile);
 		error("Offending key in %s:%d", host_file, host_line);
+		xfree(fp);
 
 		/*
 		 * If strict host key checking is in use, the user will have
 		 * to edit the key manually and we can only abort.
 		 */
-		if (options.strict_host_key_checking)
-			fatal("%s host key for %.200s has changed and you have requested strict checking.", type, host);
+		if (options.strict_host_key_checking) {
+			error("%s host key for %.200s has changed and you have "
+			    "requested strict checking.", type, host);
+			goto fail;
+		}
 
 		/*
 		 * If strict host key checking has not been requested, allow
-		 * the connection but without password authentication or
+		 * the connection but without MITM-able authentication or
 		 * agent forwarding.
 		 */
 		if (options.password_authentication) {
-			error("Password authentication is disabled to avoid trojan horses.");
+			error("Password authentication is disabled to avoid "
+			    "man-in-the-middle attacks.");
 			options.password_authentication = 0;
 		}
+		if (options.kbd_interactive_authentication) {
+			error("Keyboard-interactive authentication is disabled"
+			    " to avoid man-in-the-middle attacks.");
+			options.kbd_interactive_authentication = 0;
+			options.challenge_response_authentication = 0;
+		}
+		if (options.challenge_response_authentication) {
+			error("Challenge/response authentication is disabled"
+			    " to avoid man-in-the-middle attacks.");
+			options.challenge_response_authentication = 0;
+		}
 		if (options.forward_agent) {
-			error("Agent forwarding is disabled to avoid trojan horses.");
+			error("Agent forwarding is disabled to avoid "
+			    "man-in-the-middle attacks.");
 			options.forward_agent = 0;
 		}
 		if (options.forward_x11) {
-			error("X11 forwarding is disabled to avoid trojan horses.");
+			error("X11 forwarding is disabled to avoid "
+			    "man-in-the-middle attacks.");
 			options.forward_x11 = 0;
 		}
-	        if (options.num_local_forwards > 0 || options.num_remote_forwards > 0) {
-			error("Port forwarding is disabled to avoid trojan horses.");
-			options.num_local_forwards = options.num_remote_forwards = 0;
+		if (options.num_local_forwards > 0 ||
+		    options.num_remote_forwards > 0) {
+			error("Port forwarding is disabled to avoid "
+			    "man-in-the-middle attacks.");
+			options.num_local_forwards =
+			    options.num_remote_forwards = 0;
 		}
 		/*
 		 * XXX Should permit the user to change to use the new id.
@@ -699,9 +861,82 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
 		 * accept the authentication.
 		 */
 		break;
+	case HOST_FOUND:
+		fatal("internal error");
+		break;
 	}
 
+	if (options.check_host_ip && host_status != HOST_CHANGED &&
+	    ip_status == HOST_CHANGED) {
+		snprintf(msg, sizeof(msg),
+		    "Warning: the %s host key for '%.200s' "
+		    "differs from the key for the IP address '%.128s'"
+		    "\nOffending key for IP in %s:%d",
+		    type, host, ip, ip_file, ip_line);
+		if (host_status == HOST_OK) {
+			len = strlen(msg);
+			snprintf(msg + len, sizeof(msg) - len,
+			    "\nMatching host key in %s:%d",
+			    host_file, host_line);
+		}
+		if (options.strict_host_key_checking == 1) {
+			logit("%s", msg);
+			error("Exiting, you have requested strict checking.");
+			goto fail;
+		} else if (options.strict_host_key_checking == 2) {
+			strlcat(msg, "\nAre you sure you want "
+			    "to continue connecting (yes/no)? ", sizeof(msg));
+			if (!confirm(msg))
+				goto fail;
+		} else {
+			logit("%s", msg);
+		}
+	}
+
+	xfree(ip);
+	return 0;
+
+fail:
 	xfree(ip);
+	return -1;
+}
+
+/* returns 0 if key verifies or -1 if key does NOT verify */
+int
+verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
+{
+	struct stat st;
+
+#ifdef DNS
+	if (options.verify_host_key_dns) {
+		switch(verify_host_key_dns(host, hostaddr, host_key)) {
+		case DNS_VERIFY_OK:
+#ifdef DNSSEC
+			return 0;
+#else
+			verified_host_key_dns = 1;
+			break;
+#endif
+		case DNS_VERIFY_FAILED:
+			return -1;
+		case DNS_VERIFY_ERROR:
+			break;
+		default:
+			debug3("bad return value from verify_host_key_dns");
+			break;
+		}
+	}
+#endif /* DNS */
+
+	/* return ok if the key can be found in an old keyfile */
+	if (stat(options.system_hostfile2, &st) == 0 ||
+	    stat(options.user_hostfile2, &st) == 0) {
+		if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
+		    options.user_hostfile2, options.system_hostfile2) == 0)
+			return 0;
+	}
+	return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
+	    options.user_hostfile, options.system_hostfile);
 }
 
 /*
@@ -712,17 +947,12 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
  * This function does not require super-user privileges.
  */
 void
-ssh_login(int host_key_valid, RSA *own_host_key, const char *orighost,
-    struct sockaddr *hostaddr, uid_t original_real_uid)
+ssh_login(Sensitive *sensitive, const char *orighost,
+    struct sockaddr *hostaddr, struct passwd *pw)
 {
-	struct passwd *pw;
 	char *host, *cp;
 	char *server_user, *local_user;
 
-	/* Get local user name.  Use it as server user if no user name was given. */
-	pw = getpwuid(original_real_uid);
-	if (!pw)
-		fatal("User id %u not found from user database.", original_real_uid);
 	local_user = xstrdup(pw->pw_name);
 	server_user = options.user ? options.user : local_user;
 
@@ -742,9 +972,83 @@ ssh_login(int host_key_valid, RSA *own_host_key, const char *orighost,
 	/* authenticate user */
 	if (compat20) {
 		ssh_kex2(host, hostaddr);
-		ssh_userauth2(server_user, host);
+		ssh_userauth2(local_user, server_user, host, sensitive);
 	} else {
 		ssh_kex(host, hostaddr);
-		ssh_userauth(local_user, server_user, host, host_key_valid, own_host_key);
+		ssh_userauth1(local_user, server_user, host, sensitive);
+	}
+}
+
+void
+ssh_put_password(char *password)
+{
+	int size;
+	char *padded;
+
+	if (datafellows & SSH_BUG_PASSWORDPAD) {
+		packet_put_cstring(password);
+		return;
+	}
+	size = roundup(strlen(password) + 1, 32);
+	padded = xmalloc(size);
+	memset(padded, 0, size);
+	strlcpy(padded, password, size);
+	packet_put_string(padded, size);
+	memset(padded, 0, size);
+	xfree(padded);
+}
+
+static int
+show_key_from_file(const char *file, const char *host, int keytype)
+{
+	Key *found;
+	char *fp;
+	int line, ret;
+
+	found = key_new(keytype);
+	if ((ret = lookup_key_in_hostfile_by_type(file, host,
+	    keytype, found, &line))) {
+		fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
+		logit("WARNING: %s key found for host %s\n"
+		    "in %s:%d\n"
+		    "%s key fingerprint %s.",
+		    key_type(found), host, file, line,
+		    key_type(found), fp);
+		xfree(fp);
+	}
+	key_free(found);
+	return (ret);
+}
+
+/* print all known host keys for a given host, but skip keys of given type */
+static int
+show_other_keys(const char *host, Key *key)
+{
+	int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
+	int i, found = 0;
+
+	for (i = 0; type[i] != -1; i++) {
+		if (type[i] == key->type)
+			continue;
+		if (type[i] != KEY_RSA1 &&
+		    show_key_from_file(options.user_hostfile2, host, type[i])) {
+			found = 1;
+			continue;
+		}
+		if (type[i] != KEY_RSA1 &&
+		    show_key_from_file(options.system_hostfile2, host, type[i])) {
+			found = 1;
+			continue;
+		}
+		if (show_key_from_file(options.user_hostfile, host, type[i])) {
+			found = 1;
+			continue;
+		}
+		if (show_key_from_file(options.system_hostfile, host, type[i])) {
+			found = 1;
+			continue;
+		}
+		debug2("no key of type %d for host %s", type[i], host);
 	}
+	return (found);
 }