X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/5260325f3150ad441f310d31239beeb765f716ed..3dc1102ec55da4c4f412db1224270bd3e60962cc:/ssh.c

diff --git a/ssh.c b/ssh.c
index aade7ba5..499a901d 100644
--- a/ssh.c
+++ b/ssh.c
@@ -13,6 +13,10 @@
 #include "includes.h"
 RCSID("$Id$");
 
+#include <openssl/evp.h>
+#include <openssl/dsa.h>
+#include <openssl/rsa.h>
+
 #include "xmalloc.h"
 #include "ssh.h"
 #include "packet.h"
@@ -21,44 +25,71 @@ RCSID("$Id$");
 #include "readconf.h"
 #include "uidswap.h"
 
+#include "ssh2.h"
+#include "compat.h"
+#include "channels.h"
+#include "key.h"
+#include "authfile.h"
+
 #ifdef HAVE___PROGNAME
 extern char *__progname;
 #else /* HAVE___PROGNAME */
-const char *__progname = "ssh";
+static const char *__progname = "ssh";
 #endif /* HAVE___PROGNAME */
 
+/* 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
+
 /* Flag indicating whether debug mode is on.  This can be set on the command line. */
 int debug_flag = 0;
 
-/* Flag indicating whether to allocate a pseudo tty.  This can be set on the command
-   line, and is automatically set if no command is given on the command line. */
+/* Flag indicating whether a tty should be allocated */
 int tty_flag = 0;
 
-/* Flag indicating that nothing should be read from stdin.  This can be set
-   on the command line. */
+/* don't exec a shell */
+int no_shell_flag = 0;
+int no_tty_flag = 0;
+
+/*
+ * Flag indicating that nothing should be read from stdin.  This can be set
+ * on the command line.
+ */
 int stdin_null_flag = 0;
 
-/* Flag indicating that ssh should fork after authentication.  This is useful
-   so that the pasphrase can be entered manually, and then ssh goes to the
-   background. */
+/*
+ * Flag indicating that ssh should fork after authentication.  This is useful
+ * so that the pasphrase can be entered manually, and then ssh goes to the
+ * background.
+ */
 int fork_after_authentication_flag = 0;
 
-/* General data structure for command line options and options configurable
-   in configuration files.  See readconf.h. */
+/*
+ * General data structure for command line options and options configurable
+ * in configuration files.  See readconf.h.
+ */
 Options options;
 
-/* Name of the host we are connecting to.  This is the name given on the
-   command line, or the HostName specified for the user-supplied name
-   in a configuration file. */
+/*
+ * Name of the host we are connecting to.  This is the name given on the
+ * command line, or the HostName specified for the user-supplied name in a
+ * configuration file.
+ */
 char *host;
 
 /* socket address the host resolves to */
-struct sockaddr_in hostaddr;
+struct sockaddr_storage hostaddr;
 
-/* Flag to indicate that we have received a window change signal which has
-   not yet been processed.  This will cause a message indicating the new
-   window size to be sent to the server a little later.  This is volatile
-   because this is updated in a signal handler. */
+/*
+ * Flag to indicate that we have received a window change signal which has
+ * not yet been processed.  This will cause a message indicating the new
+ * window size to be sent to the server a little later.  This is volatile
+ * because this is updated in a signal handler.
+ */
 volatile int received_window_change_signal = 0;
 
 /* Value of argv[0] (set in the main program). */
@@ -73,6 +104,9 @@ RSA *host_private_key = NULL;
 /* Original real UID. */
 uid_t original_real_uid;
 
+/* command to be executed */
+Buffer command;
+
 /* Prints a help message to the user.  This function never returns. */
 
 void
@@ -89,6 +123,7 @@ usage()
 	fprintf(stderr, "  -x          Disable X11 connection forwarding.\n");
 	fprintf(stderr, "  -i file     Identity for RSA authentication (default: ~/.ssh/identity).\n");
 	fprintf(stderr, "  -t          Tty; allocate a tty even if command is given.\n");
+	fprintf(stderr, "  -T          Do not allocate a tty.\n");
 	fprintf(stderr, "  -v          Verbose; display verbose debugging messages.\n");
 	fprintf(stderr, "  -V          Display version number only.\n");
 	fprintf(stderr, "  -P          Don't allocate a privileged port.\n");
@@ -105,7 +140,11 @@ usage()
 	fprintf(stderr, "              These cause %s to listen for connections on a port, and\n", av0);
 	fprintf(stderr, "              forward them to the other side by connecting to host:port.\n");
 	fprintf(stderr, "  -C          Enable compression.\n");
+	fprintf(stderr, "  -N          Do not execute a shell or command.\n");
 	fprintf(stderr, "  -g          Allow remote hosts to connect to forwarded ports.\n");
+	fprintf(stderr, "  -4          Use IPv4 only.\n");
+	fprintf(stderr, "  -6          Use IPv6 only.\n");
+	fprintf(stderr, "  -2          Force protocol version 2.\n");
 	fprintf(stderr, "  -o 'option' Process the option as if it was read from a configuration file.\n");
 	exit(1);
 }
@@ -148,25 +187,27 @@ rsh_connect(char *host, char *user, Buffer * command)
 	exit(1);
 }
 
+int ssh_session(void);
+int ssh_session2(void);
+
 /*
  * Main program for the ssh client.
  */
 int
 main(int ac, char **av)
 {
-	int i, opt, optind, type, exit_status, ok, fwd_port, fwd_host_port,
-	 authfd;
+	int i, opt, optind, exit_status, ok;
+	u_short fwd_port, fwd_host_port;
 	char *optarg, *cp, buf[256];
-	Buffer command;
-	struct winsize ws;
 	struct stat st;
 	struct passwd *pw, pwcopy;
-	int interactive = 0, dummy;
+	int dummy;
 	uid_t original_effective_uid;
-	int plen;
 
-	/* Save the original real uid.  It will be needed later
-	   (uid-swapping may clobber the real uid).  */
+	/*
+	 * Save the original real uid.  It will be needed later (uid-swapping
+	 * may clobber the real uid).
+	 */
 	original_real_uid = getuid();
 	original_effective_uid = geteuid();
 
@@ -177,18 +218,21 @@ main(int ac, char **av)
 		if (setrlimit(RLIMIT_CORE, &rlim) < 0)
 			fatal("setrlimit failed: %.100s", strerror(errno));
 	}
-	/* Use uid-swapping to give up root privileges for the duration of
-	   option processing.  We will re-instantiate the rights when we
-	   are ready to create the privileged port, and will permanently
-	   drop them when the port has been created (actually, when the
-	   connection has been made, as we may need to create the port
-	   several times). */
+	/*
+	 * Use uid-swapping to give up root privileges for the duration of
+	 * option processing.  We will re-instantiate the rights when we are
+	 * ready to create the privileged port, and will permanently drop
+	 * them when the port has been created (actually, when the connection
+	 * has been made, as we may need to create the port several times).
+	 */
 	temporarily_use_uid(original_real_uid);
 
-	/* Set our umask to something reasonable, as some files are
-	   created with the default umask.  This will make them
-	   world-readable but writable only by the owner, which is ok for
-	   all files for which we don't set the modes explicitly. */
+	/*
+	 * Set our umask to something reasonable, as some files are created
+	 * with the default umask.  This will make them world-readable but
+	 * writable only by the owner, which is ok for all files for which we
+	 * don't set the modes explicitly.
+	 */
 	umask(022);
 
 	/* Save our own name. */
@@ -214,6 +258,8 @@ main(int ac, char **av)
 			if (host)
 				break;
 			if ((cp = strchr(av[optind], '@'))) {
+				if(cp == av[optind])
+					usage();
 				options.user = av[optind];
 				*cp = '\0';
 				host = ++cp;
@@ -237,31 +283,34 @@ main(int ac, char **av)
 			optarg = NULL;
 		}
 		switch (opt) {
+		case '2':
+			options.protocol = SSH_PROTO_2;
+			break;
+		case '4':
+			IPv4or6 = AF_INET;
+			break;
+		case '6':
+			IPv4or6 = AF_INET6;
+			break;
 		case 'n':
 			stdin_null_flag = 1;
 			break;
-
 		case 'f':
 			fork_after_authentication_flag = 1;
 			stdin_null_flag = 1;
 			break;
-
 		case 'x':
 			options.forward_x11 = 0;
 			break;
-
 		case 'X':
 			options.forward_x11 = 1;
 			break;
-
 		case 'g':
 			options.gateway_ports = 1;
 			break;
-
 		case 'P':
 			options.use_privileged_port = 0;
 			break;
-
 		case 'a':
 			options.forward_agent = 0;
 			break;
@@ -283,26 +332,24 @@ main(int ac, char **av)
 			options.identity_files[options.num_identity_files++] =
 				xstrdup(optarg);
 			break;
-
 		case 't':
 			tty_flag = 1;
 			break;
-
 		case 'v':
 		case 'V':
-			fprintf(stderr, "SSH Version %s, protocol version %d.%d.\n",
-			    SSH_VERSION, PROTOCOL_MAJOR, PROTOCOL_MINOR);
-			fprintf(stderr, "Compiled with SSL.\n");
+			fprintf(stderr, "SSH Version %s, protocol versions %d.%d/%d.%d.\n",
+			    SSH_VERSION,
+			    PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1,
+			    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
+			fprintf(stderr, "Compiled with SSL (0x%8.8lx).\n", SSLeay());
 			if (opt == 'V')
 				exit(0);
 			debug_flag = 1;
 			options.log_level = SYSLOG_LEVEL_DEBUG;
 			break;
-
 		case 'q':
 			options.log_level = SYSLOG_LEVEL_QUIET;
 			break;
-
 		case 'e':
 			if (optarg[0] == '^' && optarg[2] == 0 &&
 			    (unsigned char) optarg[1] >= 64 && (unsigned char) optarg[1] < 128)
@@ -316,58 +363,64 @@ main(int ac, char **av)
 				exit(1);
 			}
 			break;
-
 		case 'c':
-			options.cipher = cipher_number(optarg);
-			if (options.cipher == -1) {
-				fprintf(stderr, "Unknown cipher type '%s'\n", optarg);
-				exit(1);
+			if (ciphers_valid(optarg)) {
+				/* SSH2 only */
+				options.ciphers = xstrdup(optarg);
+				options.cipher = SSH_CIPHER_ILLEGAL;
+			} else {
+				/* SSH1 only */
+				options.cipher = cipher_number(optarg);
+				if (options.cipher == -1) {
+					fprintf(stderr, "Unknown cipher type '%s'\n", optarg);
+					exit(1);
+				}
 			}
 			break;
-
 		case 'p':
 			options.port = atoi(optarg);
-			if (options.port < 1 || options.port > 65535) {
-				fprintf(stderr, "Bad port %s.\n", optarg);
-				exit(1);
-			}
 			break;
-
 		case 'l':
 			options.user = optarg;
 			break;
-
 		case 'R':
-			if (sscanf(optarg, "%d:%255[^:]:%d", &fwd_port, buf,
-				   &fwd_host_port) != 3) {
+			if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
+			    &fwd_host_port) != 3 &&
+			    sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
+			    &fwd_host_port) != 3) {
 				fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
 				usage();
 				/* NOTREACHED */
 			}
 			add_remote_forward(&options, fwd_port, buf, fwd_host_port);
 			break;
-
 		case 'L':
-			if (sscanf(optarg, "%d:%255[^:]:%d", &fwd_port, buf,
-				   &fwd_host_port) != 3) {
+			if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf,
+			    &fwd_host_port) != 3 &&
+			    sscanf(optarg, "%hu:%255[^:]:%hu", &fwd_port, buf,
+			    &fwd_host_port) != 3) {
 				fprintf(stderr, "Bad forwarding specification '%s'.\n", optarg);
 				usage();
 				/* NOTREACHED */
 			}
 			add_local_forward(&options, fwd_port, buf, fwd_host_port);
 			break;
-
 		case 'C':
 			options.compression = 1;
 			break;
-
+		case 'N':
+			no_shell_flag = 1;
+			no_tty_flag = 1;
+			break;
+		case 'T':
+			no_tty_flag = 1;
+			break;
 		case 'o':
 			dummy = 1;
 			if (process_config_line(&options, host ? host : "", optarg,
 					 "command-line", 0, &dummy) != 0)
 				exit(1);
 			break;
-
 		default:
 			usage();
 		}
@@ -377,20 +430,16 @@ main(int ac, char **av)
 	if (!host)
 		usage();
 
-	/* check if RSA support exists */
-	if (rsa_alive() == 0) {
-		fprintf(stderr,
-			"%s: no RSA support in libssl and libcrypto.  See ssl(8).\n",
-			__progname);
-		exit(1);
-	}
 	/* Initialize the command to execute on remote host. */
 	buffer_init(&command);
 
-	/* Save the command to execute on the remote host in a buffer.
-	   There is no limit on the length of the command, except by the
-	   maximum packet size.  Also sets the tty flag if there is no
-	   command. */
+	OpenSSL_add_all_algorithms();
+	
+	/*
+	 * Save the command to execute on the remote host in a buffer. There
+	 * is no limit on the length of the command, except by the maximum
+	 * packet size.  Also sets the tty flag if there is no command.
+	 */
 	if (optind == ac) {
 		/* No command specified - execute shell on a tty. */
 		tty_flag = 1;
@@ -418,6 +467,10 @@ main(int ac, char **av)
 			fprintf(stderr, "Pseudo-terminal will not be allocated because stdin is not a terminal.\n");
 		tty_flag = 0;
 	}
+	/* force */
+	if (no_tty_flag)
+		tty_flag = 0;
+
 	/* Get user data. */
 	pw = getpwuid(original_real_uid);
 	if (!pw) {
@@ -451,6 +504,20 @@ main(int ac, char **av)
 	/* reinit */
 	log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0);
 
+	/* check if RSA support exists */
+	if ((options.protocol & SSH_PROTO_1) &&
+	    rsa_alive() == 0) {
+		log("%s: no RSA support in libssl and libcrypto.  See ssl(8).",
+		    __progname);
+		log("Disabling protocol version 1");
+		options.protocol &= ~ (SSH_PROTO_1|SSH_PROTO_1_PREFERRED);
+	}
+	if (! options.protocol & (SSH_PROTO_1|SSH_PROTO_2)) {
+		fprintf(stderr, "%s: No protocol version available.\n",
+		    __progname);
+ 		exit(1);
+	}
+
 	if (options.user == NULL)
 		options.user = xstrdup(pw->pw_name);
 
@@ -459,14 +526,18 @@ main(int ac, char **av)
 
 	/* Find canonic host name. */
 	if (strchr(host, '.') == 0) {
-		struct hostent *hp = gethostbyname(host);
-		if (hp != 0) {
-			if (strchr(hp->h_name, '.') != 0)
-				host = xstrdup(hp->h_name);
-			else if (hp->h_aliases != 0
-				 && hp->h_aliases[0] != 0
-				 && strchr(hp->h_aliases[0], '.') != 0)
-				host = xstrdup(hp->h_aliases[0]);
+		struct addrinfo hints;
+		struct addrinfo *ai = NULL;
+		int errgai;
+		memset(&hints, 0, sizeof(hints));
+		hints.ai_family = IPv4or6;
+		hints.ai_flags = AI_CANONNAME;
+		hints.ai_socktype = SOCK_STREAM;
+		errgai = getaddrinfo(host, NULL, &hints, &ai);
+		if (errgai == 0) {
+			if (ai->ai_canonname != NULL)
+				host = xstrdup(ai->ai_canonname);
+			freeaddrinfo(ai);
 		}
 	}
 	/* Disable rhosts authentication if not running as root. */
@@ -474,11 +545,15 @@ main(int ac, char **av)
 		options.rhosts_authentication = 0;
 		options.rhosts_rsa_authentication = 0;
 	}
-	/* If using rsh has been selected, exec it now (without trying
-	   anything else).  Note that we must release privileges first. */
+	/*
+	 * If using rsh has been selected, exec it now (without trying
+	 * anything else).  Note that we must release privileges first.
+	 */
 	if (options.use_rsh) {
-		/* Restore our superuser privileges.  This must be done
-		   before permanently setting the uid. */
+		/*
+		 * Restore our superuser privileges.  This must be done
+		 * before permanently setting the uid.
+		 */
 		restore_uid();
 
 		/* Switch to the original uid permanently. */
@@ -491,8 +566,10 @@ main(int ac, char **av)
 	/* Restore our superuser privileges. */
 	restore_uid();
 
-	/* Open a connection to the remote host.  This needs root
-	   privileges if rhosts_{rsa_}authentication is enabled. */
+	/*
+	 * Open a connection to the remote host.  This needs root privileges
+	 * if rhosts_{rsa_}authentication is enabled.
+	 */
 
 	ok = ssh_connect(host, &hostaddr, options.port,
 			 options.connection_attempts,
@@ -501,31 +578,41 @@ main(int ac, char **av)
 			 original_real_uid,
 			 options.proxy_command);
 
-	/* If we successfully made the connection, load the host private
-	   key in case we will need it later for combined rsa-rhosts
-	   authentication. This must be done before releasing extra
-	   privileges, because the file is only readable by root. */
-	if (ok) {
+	/*
+	 * If we successfully made the connection, load the host private key
+	 * in case we will need it later for combined rsa-rhosts
+	 * authentication. This must be done before releasing extra
+	 * privileges, because the file is only readable by root.
+	 */
+	if (ok && (options.protocol & SSH_PROTO_1)) {
+		Key k;
 		host_private_key = RSA_new();
-		if (load_private_key(HOST_KEY_FILE, "", host_private_key, NULL))
+		k.type = KEY_RSA;
+		k.rsa = host_private_key;
+		if (load_private_key(HOST_KEY_FILE, "", &k, NULL))
 			host_private_key_loaded = 1;
 	}
-	/* Get rid of any extra privileges that we may have.  We will no
-	   longer need them.  Also, extra privileges could make it very
-	   hard to read identity files and other non-world-readable files
-	   from the user's home directory if it happens to be on a NFS
-	   volume where root is mapped to nobody. */
-
-	/* Note that some legacy systems need to postpone the following
-	   call to permanently_set_uid() until the private hostkey is
-	   destroyed with RSA_free().  Otherwise the calling user could
-	   ptrace() the process, read the private hostkey and impersonate
-	   the host.  OpenBSD does not allow ptracing of setuid processes. */
-
+	/*
+	 * Get rid of any extra privileges that we may have.  We will no
+	 * longer need them.  Also, extra privileges could make it very hard
+	 * to read identity files and other non-world-readable files from the
+	 * user's home directory if it happens to be on a NFS volume where
+	 * root is mapped to nobody.
+	 */
+
+	/*
+	 * Note that some legacy systems need to postpone the following call
+	 * to permanently_set_uid() until the private hostkey is destroyed
+	 * with RSA_free().  Otherwise the calling user could ptrace() the
+	 * process, read the private hostkey and impersonate the host.
+	 * OpenBSD does not allow ptracing of setuid processes.
+	 */
 	permanently_set_uid(original_real_uid);
 
-	/* Now that we are back to our own permissions, create ~/.ssh
-	   directory if it doesn\'t already exist. */
+	/*
+	 * Now that we are back to our own permissions, create ~/.ssh
+	 * directory if it doesn\'t already exist.
+	 */
 	snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_DIR);
 	if (stat(buf, &st) < 0)
 		if (mkdir(buf, 0755) < 0)
@@ -534,7 +621,7 @@ main(int ac, char **av)
 	/* Check if the connection failed, and try "rsh" if appropriate. */
 	if (!ok) {
 		if (options.port != 0)
-			log("Secure connection to %.100s on port %d refused%.100s.",
+			log("Secure connection to %.100s on port %hu refused%.100s.",
 			    host, options.port,
 			    options.fallback_to_rsh ? "; reverting to insecure method" : "");
 		else
@@ -548,36 +635,87 @@ main(int ac, char **av)
 		exit(1);
 	}
 	/* Expand ~ in options.identity_files. */
+	/* XXX mem-leaks */
 	for (i = 0; i < options.num_identity_files; i++)
 		options.identity_files[i] =
 			tilde_expand_filename(options.identity_files[i], original_real_uid);
-
+	for (i = 0; i < options.num_identity_files2; i++)
+		options.identity_files2[i] =
+			tilde_expand_filename(options.identity_files2[i], original_real_uid);
 	/* Expand ~ in known host file names. */
 	options.system_hostfile = tilde_expand_filename(options.system_hostfile,
-						        original_real_uid);
+	    original_real_uid);
 	options.user_hostfile = tilde_expand_filename(options.user_hostfile,
-						      original_real_uid);
+	    original_real_uid);
+	options.system_hostfile2 = tilde_expand_filename(options.system_hostfile2,
+	    original_real_uid);
+	options.user_hostfile2 = tilde_expand_filename(options.user_hostfile2,
+	    original_real_uid);
 
 	/* Log into the remote system.  This never returns if the login fails. */
 	ssh_login(host_private_key_loaded, host_private_key,
-		  host, &hostaddr, original_real_uid);
+		  host, (struct sockaddr *)&hostaddr, original_real_uid);
 
 	/* We no longer need the host private key.  Clear it now. */
 	if (host_private_key_loaded)
 		RSA_free(host_private_key);	/* Destroys contents safely */
 
-	/* Close connection cleanly after attack. */
-	cipher_attack_detected = packet_disconnect;
-
-	/* If requested, fork and let ssh continue in the background. */
-	if (fork_after_authentication_flag) {
-		int ret = fork();
-		if (ret == -1)
-			fatal("fork failed: %.100s", strerror(errno));
-		if (ret != 0)
-			exit(0);
-		setsid();
+	exit_status = compat20 ? ssh_session2() : ssh_session();
+	packet_close();
+	return exit_status;
+}
+
+void
+x11_get_proto(char *proto, int proto_len, char *data, int data_len)
+{
+	char line[512];
+	FILE *f;
+	int got_data = 0, i;
+
+#ifdef XAUTH_PATH
+	/* Try to get Xauthority information for the display. */
+	snprintf(line, sizeof line, "%.100s list %.200s 2>/dev/null",
+		 XAUTH_PATH, getenv("DISPLAY"));
+	f = popen(line, "r");
+	if (f && fgets(line, sizeof(line), f) &&
+	    sscanf(line, "%*s %s %s", proto, data) == 2)
+		got_data = 1;
+	if (f)
+		pclose(f);
+#endif /* XAUTH_PATH */
+	/*
+	 * If we didn't get authentication data, just make up some
+	 * data.  The forwarding code will check the validity of the
+	 * response anyway, and substitute this data.  The X11
+	 * server, however, will ignore this fake data and use
+	 * whatever authentication mechanisms it was using otherwise
+	 * for the local connection.
+	 */
+	if (!got_data) {
+		u_int32_t rand = 0;
+
+		strlcpy(proto, "MIT-MAGIC-COOKIE-1", proto_len);
+		for (i = 0; i < 16; i++) {
+			if (i % 4 == 0)
+				rand = arc4random();
+			snprintf(data + 2 * i, data_len - 2 * i, "%02x", rand & 0xff);
+			rand >>= 8;
+		}
 	}
+}
+
+int
+ssh_session(void)
+{
+	int type;
+	int i;
+	int plen;
+	int interactive = 0;
+	int have_tty = 0;
+	struct winsize ws;
+	int authfd;
+	char *cp;
+
 	/* Enable compression if requested. */
 	if (options.compression) {
 		debug("Requesting compression at level %d.", options.compression_level);
@@ -629,61 +767,32 @@ main(int ac, char **av)
 
 		/* Read response from the server. */
 		type = packet_read(&plen);
-		if (type == SSH_SMSG_SUCCESS)
+		if (type == SSH_SMSG_SUCCESS) {
 			interactive = 1;
-		else if (type == SSH_SMSG_FAILURE)
+			have_tty = 1;
+		} else if (type == SSH_SMSG_FAILURE)
 			log("Warning: Remote host failed or refused to allocate a pseudo tty.");
 		else
 			packet_disconnect("Protocol error waiting for pty request response.");
 	}
 	/* Request X11 forwarding if enabled and DISPLAY is set. */
 	if (options.forward_x11 && getenv("DISPLAY") != NULL) {
-		char line[512], proto[512], data[512];
-		FILE *f;
-		int forwarded = 0, got_data = 0, i;
-
-#ifdef XAUTH_PATH
-		/* Try to get Xauthority information for the display. */
-		snprintf(line, sizeof line, "%.100s list %.200s 2>/dev/null",
-			 XAUTH_PATH, getenv("DISPLAY"));
-		f = popen(line, "r");
-		if (f && fgets(line, sizeof(line), f) &&
-		    sscanf(line, "%*s %s %s", proto, data) == 2)
-			got_data = 1;
-		if (f)
-			pclose(f);
-#endif /* XAUTH_PATH */
-		/* If we didn't get authentication data, just make up some
-		   data.  The forwarding code will check the validity of
-		   the response anyway, and substitute this data.  The X11
-		   server, however, will ignore this fake data and use
-		   whatever authentication mechanisms it was using
-		   otherwise for the local connection. */
-		if (!got_data) {
-			u_int32_t rand = 0;
-
-			strlcpy(proto, "MIT-MAGIC-COOKIE-1", sizeof proto);
-			for (i = 0; i < 16; i++) {
-				if (i % 4 == 0)
-					rand = arc4random();
-				snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", rand & 0xff);
-				rand >>= 8;
-			}
-		}
-		/* Got local authentication reasonable information.
-		   Request forwarding with authentication spoofing. */
+		char proto[512], data[512];
+		/* Get reasonable local authentication information. */
+		x11_get_proto(proto, sizeof proto, data, sizeof data);
+		/* Request forwarding with authentication spoofing. */
 		debug("Requesting X11 forwarding with authentication spoofing.");
-		x11_request_forwarding_with_spoofing(proto, data);
+		x11_request_forwarding_with_spoofing(0, proto, data);
 
 		/* Read response from the server. */
 		type = packet_read(&plen);
 		if (type == SSH_SMSG_SUCCESS) {
-			forwarded = 1;
 			interactive = 1;
-		} else if (type == SSH_SMSG_FAILURE)
+		} else if (type == SSH_SMSG_FAILURE) {
 			log("Warning: Remote host denied X11 forwarding.");
-		else
+		} else {
 			packet_disconnect("Protocol error waiting for X11 forwarding");
+		}
 	}
 	/* Tell the packet module whether this is an interactive session. */
 	packet_set_interactive(interactive, options.keepalives);
@@ -713,8 +822,9 @@ main(int ac, char **av)
 		      options.local_forwards[i].host,
 		      options.local_forwards[i].host_port);
 		channel_request_local_forwarding(options.local_forwards[i].port,
-					  	 options.local_forwards[i].host,
-						 options.local_forwards[i].host_port);
+						 options.local_forwards[i].host,
+						 options.local_forwards[i].host_port,
+						 options.gateway_ports);
 	}
 
 	/* Initiate remote TCP/IP port forwardings. */
@@ -725,11 +835,18 @@ main(int ac, char **av)
 		      options.remote_forwards[i].host_port);
 		channel_request_remote_forwarding(options.remote_forwards[i].port,
 						  options.remote_forwards[i].host,
-				   		  options.remote_forwards[i].host_port);
+						  options.remote_forwards[i].host_port);
 	}
 
-	/* If a command was specified on the command line, execute the
-	   command now. Otherwise request the server to start a shell. */
+	/* If requested, let ssh continue in the background. */
+	if (fork_after_authentication_flag)
+		if (daemon(1, 1) < 0)
+			fatal("daemon() failed: %.200s", strerror(errno));
+
+	/*
+	 * If a command was specified on the command line, execute the
+	 * command now. Otherwise request the server to start a shell.
+	 */
 	if (buffer_len(&command) > 0) {
 		int len = buffer_len(&command);
 		if (len > 900)
@@ -747,11 +864,114 @@ main(int ac, char **av)
 	}
 
 	/* Enter the interactive session. */
-	exit_status = client_loop(tty_flag, tty_flag ? options.escape_char : -1);
+	return client_loop(have_tty, tty_flag ? options.escape_char : -1);
+}
 
-	/* Close the connection to the remote host. */
-	packet_close();
+void
+init_local_fwd(void)
+{
+	int i;
+	/* Initiate local TCP/IP port forwardings. */
+	for (i = 0; i < options.num_local_forwards; i++) {
+		debug("Connections to local port %d forwarded to remote address %.200s:%d",
+		      options.local_forwards[i].port,
+		      options.local_forwards[i].host,
+		      options.local_forwards[i].host_port);
+		channel_request_local_forwarding(options.local_forwards[i].port,
+						 options.local_forwards[i].host,
+						 options.local_forwards[i].host_port,
+						 options.gateway_ports);
+	}
+}
+
+extern void client_set_session_ident(int id);
+
+void
+client_init(int id, void *arg)
+{
+	int len;
+	debug("client_init id %d arg %d", id, (int)arg);
+
+	if (no_shell_flag)
+		goto done;
+
+	if (tty_flag) {
+		struct winsize ws;
+		char *cp;
+		cp = getenv("TERM");
+		if (!cp)
+			cp = "";
+		/* Store window size in the packet. */
+		if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0)
+			memset(&ws, 0, sizeof(ws));
+
+		channel_request_start(id, "pty-req", 0);
+		packet_put_cstring(cp);
+		packet_put_int(ws.ws_col);
+		packet_put_int(ws.ws_row);
+		packet_put_int(ws.ws_xpixel);
+		packet_put_int(ws.ws_ypixel);
+		packet_put_cstring("");		/* XXX: encode terminal modes */
+		packet_send();
+		/* XXX wait for reply */
+	}
+	if (options.forward_x11 &&
+	    getenv("DISPLAY") != NULL) {
+		char proto[512], data[512];
+		/* Get reasonable local authentication information. */
+		x11_get_proto(proto, sizeof proto, data, sizeof data);
+		/* Request forwarding with authentication spoofing. */
+		debug("Requesting X11 forwarding with authentication spoofing.");
+		x11_request_forwarding_with_spoofing(id, proto, data);
+		/* XXX wait for reply */
+	}
+
+	len = buffer_len(&command);
+	if (len > 0) {
+		if (len > 900)
+			len = 900;
+		debug("Sending command: %.*s", len, buffer_ptr(&command));
+		channel_request_start(id, "exec", 0);
+		packet_put_string(buffer_ptr(&command), len);
+		packet_send();
+	} else {
+		channel_request(id, "shell", 0);
+	}
+	/* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */
+done:
+	/* register different callback, etc. XXX */
+	client_set_session_ident(id);
+}
+
+int
+ssh_session2(void)
+{
+	int window, packetmax, id;
+	int in  = dup(STDIN_FILENO);
+	int out = dup(STDOUT_FILENO);
+	int err = dup(STDERR_FILENO);
+
+	if (in < 0 || out < 0 || err < 0)
+		fatal("dump in/out/err failed");
+
+	/* should be pre-session */
+	init_local_fwd();
+	
+	window = 32*1024;
+	if (tty_flag) {
+		packetmax = window/8;
+	} else {
+		window *= 2;
+		packetmax = window/2;
+	}
+
+	id = channel_new(
+	    "session", SSH_CHANNEL_OPENING, in, out, err,
+	    window, packetmax, CHAN_EXTENDED_WRITE, xstrdup("client-session"));
+
+
+	channel_open(id);
+	channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, client_init, (void *)0);
 
-	/* Exit with the status returned by the program on the remote side. */
-	exit(exit_status);
+	return client_loop(tty_flag, tty_flag ? options.escape_char : -1);
 }