Put ssh back into the repository

Change-Id: I23324372188fa6ed3f93a32b84365f5df6367590
diff --git a/readconf.c b/readconf.c
new file mode 100644
index 0000000..91dfa56
--- /dev/null
+++ b/readconf.c
@@ -0,0 +1,1473 @@
+/* $OpenBSD: readconf.c,v 1.193 2011/05/24 07:15:47 djm Exp $ */
+/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ *                    All rights reserved
+ * Functions for reading the configuration files.
+ *
+ * As far as I am concerned, the code I have written for this software
+ * can be used freely for any purpose.  Any derived versions of this
+ * software must be clearly marked as such, and if the derived work is
+ * incompatible with the protocol description in the RFC file, it must be
+ * called by a name other than "ssh" or "Secure Shell".
+ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+
+#include <netinet/in.h>
+#include <netinet/in_systm.h>
+#include <netinet/ip.h>
+
+#include <ctype.h>
+#include <errno.h>
+#include <netdb.h>
+#include <signal.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "xmalloc.h"
+#include "ssh.h"
+#include "compat.h"
+#include "cipher.h"
+#include "pathnames.h"
+#include "log.h"
+#include "key.h"
+#include "readconf.h"
+#include "match.h"
+#include "misc.h"
+#include "buffer.h"
+#include "kex.h"
+#include "mac.h"
+
+/* Format of the configuration file:
+
+   # Configuration data is parsed as follows:
+   #  1. command line options
+   #  2. user-specific file
+   #  3. system-wide file
+   # Any configuration value is only changed the first time it is set.
+   # Thus, host-specific definitions should be at the beginning of the
+   # configuration file, and defaults at the end.
+
+   # Host-specific declarations.  These may override anything above.  A single
+   # host may match multiple declarations; these are processed in the order
+   # that they are given in.
+
+   Host *.ngs.fi ngs.fi
+     User foo
+
+   Host fake.com
+     HostName another.host.name.real.org
+     User blaah
+     Port 34289
+     ForwardX11 no
+     ForwardAgent no
+
+   Host books.com
+     RemoteForward 9999 shadows.cs.hut.fi:9999
+     Cipher 3des
+
+   Host fascist.blob.com
+     Port 23123
+     User tylonen
+     PasswordAuthentication no
+
+   Host puukko.hut.fi
+     User t35124p
+     ProxyCommand ssh-proxy %h %p
+
+   Host *.fr
+     PublicKeyAuthentication no
+
+   Host *.su
+     Cipher none
+     PasswordAuthentication no
+
+   Host vpn.fake.com
+     Tunnel yes
+     TunnelDevice 3
+
+   # Defaults for various options
+   Host *
+     ForwardAgent no
+     ForwardX11 no
+     PasswordAuthentication yes
+     RSAAuthentication yes
+     RhostsRSAAuthentication yes
+     StrictHostKeyChecking yes
+     TcpKeepAlive no
+     IdentityFile ~/.ssh/identity
+     Port 22
+     EscapeChar ~
+
+*/
+
+/* Keyword tokens. */
+
+typedef enum {
+	oBadOption,
+	oForwardAgent, oForwardX11, oForwardX11Trusted, oForwardX11Timeout,
+	oGatewayPorts, oExitOnForwardFailure,
+	oPasswordAuthentication, oRSAAuthentication,
+	oChallengeResponseAuthentication, oXAuthLocation,
+	oIdentityFile, oHostName, oPort, oCipher, oRemoteForward, oLocalForward,
+	oUser, oHost, oEscapeChar, oRhostsRSAAuthentication, oProxyCommand,
+	oGlobalKnownHostsFile, oUserKnownHostsFile, oConnectionAttempts,
+	oBatchMode, oCheckHostIP, oStrictHostKeyChecking, oCompression,
+	oCompressionLevel, oTCPKeepAlive, oNumberOfPasswordPrompts,
+	oUsePrivilegedPort, oLogLevel, oCiphers, oProtocol, oMacs,
+	oGlobalKnownHostsFile2, oUserKnownHostsFile2, oPubkeyAuthentication,
+	oKbdInteractiveAuthentication, oKbdInteractiveDevices, oHostKeyAlias,
+	oDynamicForward, oPreferredAuthentications, oHostbasedAuthentication,
+	oHostKeyAlgorithms, oBindAddress, oPKCS11Provider,
+	oClearAllForwardings, oNoHostAuthenticationForLocalhost,
+	oEnableSSHKeysign, oRekeyLimit, oVerifyHostKeyDNS, oConnectTimeout,
+	oAddressFamily, oGssAuthentication, oGssDelegateCreds,
+	oServerAliveInterval, oServerAliveCountMax, oIdentitiesOnly,
+	oSendEnv, oControlPath, oControlMaster, oControlPersist,
+	oHashKnownHosts,
+	oTunnel, oTunnelDevice, oLocalCommand, oPermitLocalCommand,
+	oVisualHostKey, oUseRoaming, oZeroKnowledgePasswordAuthentication,
+	oKexAlgorithms, oIPQoS, oRequestTTY,
+	oDeprecated, oUnsupported
+} OpCodes;
+
+/* Textual representations of the tokens. */
+
+static struct {
+	const char *name;
+	OpCodes opcode;
+} keywords[] = {
+	{ "forwardagent", oForwardAgent },
+	{ "forwardx11", oForwardX11 },
+	{ "forwardx11trusted", oForwardX11Trusted },
+	{ "forwardx11timeout", oForwardX11Timeout },
+	{ "exitonforwardfailure", oExitOnForwardFailure },
+	{ "xauthlocation", oXAuthLocation },
+	{ "gatewayports", oGatewayPorts },
+	{ "useprivilegedport", oUsePrivilegedPort },
+	{ "rhostsauthentication", oDeprecated },
+	{ "passwordauthentication", oPasswordAuthentication },
+	{ "kbdinteractiveauthentication", oKbdInteractiveAuthentication },
+	{ "kbdinteractivedevices", oKbdInteractiveDevices },
+	{ "rsaauthentication", oRSAAuthentication },
+	{ "pubkeyauthentication", oPubkeyAuthentication },
+	{ "dsaauthentication", oPubkeyAuthentication },		    /* alias */
+	{ "rhostsrsaauthentication", oRhostsRSAAuthentication },
+	{ "hostbasedauthentication", oHostbasedAuthentication },
+	{ "challengeresponseauthentication", oChallengeResponseAuthentication },
+	{ "skeyauthentication", oChallengeResponseAuthentication }, /* alias */
+	{ "tisauthentication", oChallengeResponseAuthentication },  /* alias */
+	{ "kerberosauthentication", oUnsupported },
+	{ "kerberostgtpassing", oUnsupported },
+	{ "afstokenpassing", oUnsupported },
+#if defined(GSSAPI)
+	{ "gssapiauthentication", oGssAuthentication },
+	{ "gssapidelegatecredentials", oGssDelegateCreds },
+#else
+	{ "gssapiauthentication", oUnsupported },
+	{ "gssapidelegatecredentials", oUnsupported },
+#endif
+	{ "fallbacktorsh", oDeprecated },
+	{ "usersh", oDeprecated },
+	{ "identityfile", oIdentityFile },
+	{ "identityfile2", oIdentityFile },			/* obsolete */
+	{ "identitiesonly", oIdentitiesOnly },
+	{ "hostname", oHostName },
+	{ "hostkeyalias", oHostKeyAlias },
+	{ "proxycommand", oProxyCommand },
+	{ "port", oPort },
+	{ "cipher", oCipher },
+	{ "ciphers", oCiphers },
+	{ "macs", oMacs },
+	{ "protocol", oProtocol },
+	{ "remoteforward", oRemoteForward },
+	{ "localforward", oLocalForward },
+	{ "user", oUser },
+	{ "host", oHost },
+	{ "escapechar", oEscapeChar },
+	{ "globalknownhostsfile", oGlobalKnownHostsFile },
+	{ "globalknownhostsfile2", oDeprecated },
+	{ "userknownhostsfile", oUserKnownHostsFile },
+	{ "userknownhostsfile2", oDeprecated }, 
+	{ "connectionattempts", oConnectionAttempts },
+	{ "batchmode", oBatchMode },
+	{ "checkhostip", oCheckHostIP },
+	{ "stricthostkeychecking", oStrictHostKeyChecking },
+	{ "compression", oCompression },
+	{ "compressionlevel", oCompressionLevel },
+	{ "tcpkeepalive", oTCPKeepAlive },
+	{ "keepalive", oTCPKeepAlive },				/* obsolete */
+	{ "numberofpasswordprompts", oNumberOfPasswordPrompts },
+	{ "loglevel", oLogLevel },
+	{ "dynamicforward", oDynamicForward },
+	{ "preferredauthentications", oPreferredAuthentications },
+	{ "hostkeyalgorithms", oHostKeyAlgorithms },
+	{ "bindaddress", oBindAddress },
+#ifdef ENABLE_PKCS11
+	{ "smartcarddevice", oPKCS11Provider },
+	{ "pkcs11provider", oPKCS11Provider },
+#else
+	{ "smartcarddevice", oUnsupported },
+	{ "pkcs11provider", oUnsupported },
+#endif
+	{ "clearallforwardings", oClearAllForwardings },
+	{ "enablesshkeysign", oEnableSSHKeysign },
+	{ "verifyhostkeydns", oVerifyHostKeyDNS },
+	{ "nohostauthenticationforlocalhost", oNoHostAuthenticationForLocalhost },
+	{ "rekeylimit", oRekeyLimit },
+	{ "connecttimeout", oConnectTimeout },
+	{ "addressfamily", oAddressFamily },
+	{ "serveraliveinterval", oServerAliveInterval },
+	{ "serveralivecountmax", oServerAliveCountMax },
+	{ "sendenv", oSendEnv },
+	{ "controlpath", oControlPath },
+	{ "controlmaster", oControlMaster },
+	{ "controlpersist", oControlPersist },
+	{ "hashknownhosts", oHashKnownHosts },
+	{ "tunnel", oTunnel },
+	{ "tunneldevice", oTunnelDevice },
+	{ "localcommand", oLocalCommand },
+	{ "permitlocalcommand", oPermitLocalCommand },
+	{ "visualhostkey", oVisualHostKey },
+	{ "useroaming", oUseRoaming },
+#ifdef JPAKE
+	{ "zeroknowledgepasswordauthentication",
+	    oZeroKnowledgePasswordAuthentication },
+#else
+	{ "zeroknowledgepasswordauthentication", oUnsupported },
+#endif
+	{ "kexalgorithms", oKexAlgorithms },
+	{ "ipqos", oIPQoS },
+	{ "requesttty", oRequestTTY },
+
+	{ NULL, oBadOption }
+};
+
+/*
+ * Adds a local TCP/IP port forward to options.  Never returns if there is an
+ * error.
+ */
+
+void
+add_local_forward(Options *options, const Forward *newfwd)
+{
+	Forward *fwd;
+#ifndef NO_IPPORT_RESERVED_CONCEPT
+	extern uid_t original_real_uid;
+	if (newfwd->listen_port < IPPORT_RESERVED && original_real_uid != 0)
+		fatal("Privileged ports can only be forwarded by root.");
+#endif
+	options->local_forwards = xrealloc(options->local_forwards,
+	    options->num_local_forwards + 1,
+	    sizeof(*options->local_forwards));
+	fwd = &options->local_forwards[options->num_local_forwards++];
+
+	fwd->listen_host = newfwd->listen_host;
+	fwd->listen_port = newfwd->listen_port;
+	fwd->connect_host = newfwd->connect_host;
+	fwd->connect_port = newfwd->connect_port;
+}
+
+/*
+ * Adds a remote TCP/IP port forward to options.  Never returns if there is
+ * an error.
+ */
+
+void
+add_remote_forward(Options *options, const Forward *newfwd)
+{
+	Forward *fwd;
+
+	options->remote_forwards = xrealloc(options->remote_forwards,
+	    options->num_remote_forwards + 1,
+	    sizeof(*options->remote_forwards));
+	fwd = &options->remote_forwards[options->num_remote_forwards++];
+
+	fwd->listen_host = newfwd->listen_host;
+	fwd->listen_port = newfwd->listen_port;
+	fwd->connect_host = newfwd->connect_host;
+	fwd->connect_port = newfwd->connect_port;
+	fwd->allocated_port = 0;
+}
+
+static void
+clear_forwardings(Options *options)
+{
+	int i;
+
+	for (i = 0; i < options->num_local_forwards; i++) {
+		if (options->local_forwards[i].listen_host != NULL)
+			xfree(options->local_forwards[i].listen_host);
+		xfree(options->local_forwards[i].connect_host);
+	}
+	if (options->num_local_forwards > 0) {
+		xfree(options->local_forwards);
+		options->local_forwards = NULL;
+	}
+	options->num_local_forwards = 0;
+	for (i = 0; i < options->num_remote_forwards; i++) {
+		if (options->remote_forwards[i].listen_host != NULL)
+			xfree(options->remote_forwards[i].listen_host);
+		xfree(options->remote_forwards[i].connect_host);
+	}
+	if (options->num_remote_forwards > 0) {
+		xfree(options->remote_forwards);
+		options->remote_forwards = NULL;
+	}
+	options->num_remote_forwards = 0;
+	options->tun_open = SSH_TUNMODE_NO;
+}
+
+/*
+ * Returns the number of the token pointed to by cp or oBadOption.
+ */
+
+static OpCodes
+parse_token(const char *cp, const char *filename, int linenum)
+{
+	u_int i;
+
+	for (i = 0; keywords[i].name; i++)
+		if (strcasecmp(cp, keywords[i].name) == 0)
+			return keywords[i].opcode;
+
+	error("%s: line %d: Bad configuration option: %s",
+	    filename, linenum, cp);
+	return oBadOption;
+}
+
+/*
+ * Processes a single option line as used in the configuration files. This
+ * only sets those values that have not already been set.
+ */
+#define WHITESPACE " \t\r\n"
+
+int
+process_config_line(Options *options, const char *host,
+		    char *line, const char *filename, int linenum,
+		    int *activep)
+{
+	char *s, **charptr, *endofnumber, *keyword, *arg, *arg2;
+	char **cpptr, fwdarg[256];
+	u_int *uintptr, max_entries = 0;
+	int negated, opcode, *intptr, value, value2, scale;
+	LogLevel *log_level_ptr;
+	long long orig, val64;
+	size_t len;
+	Forward fwd;
+
+	/* Strip trailing whitespace */
+	for (len = strlen(line) - 1; len > 0; len--) {
+		if (strchr(WHITESPACE, line[len]) == NULL)
+			break;
+		line[len] = '\0';
+	}
+
+	s = line;
+	/* Get the keyword. (Each line is supposed to begin with a keyword). */
+	if ((keyword = strdelim(&s)) == NULL)
+		return 0;
+	/* Ignore leading whitespace. */
+	if (*keyword == '\0')
+		keyword = strdelim(&s);
+	if (keyword == NULL || !*keyword || *keyword == '\n' || *keyword == '#')
+		return 0;
+
+	opcode = parse_token(keyword, filename, linenum);
+
+	switch (opcode) {
+	case oBadOption:
+		/* don't panic, but count bad options */
+		return -1;
+		/* NOTREACHED */
+	case oConnectTimeout:
+		intptr = &options->connection_timeout;
+parse_time:
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%s line %d: missing time value.",
+			    filename, linenum);
+		if ((value = convtime(arg)) == -1)
+			fatal("%s line %d: invalid time value.",
+			    filename, linenum);
+		if (*activep && *intptr == -1)
+			*intptr = value;
+		break;
+
+	case oForwardAgent:
+		intptr = &options->forward_agent;
+parse_flag:
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing yes/no argument.", filename, linenum);
+		value = 0;	/* To avoid compiler warning... */
+		if (strcmp(arg, "yes") == 0 || strcmp(arg, "true") == 0)
+			value = 1;
+		else if (strcmp(arg, "no") == 0 || strcmp(arg, "false") == 0)
+			value = 0;
+		else
+			fatal("%.200s line %d: Bad yes/no argument.", filename, linenum);
+		if (*activep && *intptr == -1)
+			*intptr = value;
+		break;
+
+	case oForwardX11:
+		intptr = &options->forward_x11;
+		goto parse_flag;
+
+	case oForwardX11Trusted:
+		intptr = &options->forward_x11_trusted;
+		goto parse_flag;
+	
+	case oForwardX11Timeout:
+		intptr = &options->forward_x11_timeout;
+		goto parse_time;
+
+	case oGatewayPorts:
+		intptr = &options->gateway_ports;
+		goto parse_flag;
+
+	case oExitOnForwardFailure:
+		intptr = &options->exit_on_forward_failure;
+		goto parse_flag;
+
+	case oUsePrivilegedPort:
+		intptr = &options->use_privileged_port;
+		goto parse_flag;
+
+	case oPasswordAuthentication:
+		intptr = &options->password_authentication;
+		goto parse_flag;
+
+	case oZeroKnowledgePasswordAuthentication:
+		intptr = &options->zero_knowledge_password_authentication;
+		goto parse_flag;
+
+	case oKbdInteractiveAuthentication:
+		intptr = &options->kbd_interactive_authentication;
+		goto parse_flag;
+
+	case oKbdInteractiveDevices:
+		charptr = &options->kbd_interactive_devices;
+		goto parse_string;
+
+	case oPubkeyAuthentication:
+		intptr = &options->pubkey_authentication;
+		goto parse_flag;
+
+	case oRSAAuthentication:
+		intptr = &options->rsa_authentication;
+		goto parse_flag;
+
+	case oRhostsRSAAuthentication:
+		intptr = &options->rhosts_rsa_authentication;
+		goto parse_flag;
+
+	case oHostbasedAuthentication:
+		intptr = &options->hostbased_authentication;
+		goto parse_flag;
+
+	case oChallengeResponseAuthentication:
+		intptr = &options->challenge_response_authentication;
+		goto parse_flag;
+
+	case oGssAuthentication:
+		intptr = &options->gss_authentication;
+		goto parse_flag;
+
+	case oGssDelegateCreds:
+		intptr = &options->gss_deleg_creds;
+		goto parse_flag;
+
+	case oBatchMode:
+		intptr = &options->batch_mode;
+		goto parse_flag;
+
+	case oCheckHostIP:
+		intptr = &options->check_host_ip;
+		goto parse_flag;
+
+	case oVerifyHostKeyDNS:
+		intptr = &options->verify_host_key_dns;
+		goto parse_yesnoask;
+
+	case oStrictHostKeyChecking:
+		intptr = &options->strict_host_key_checking;
+parse_yesnoask:
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing yes/no/ask argument.",
+			    filename, linenum);
+		value = 0;	/* To avoid compiler warning... */
+		if (strcmp(arg, "yes") == 0 || strcmp(arg, "true") == 0)
+			value = 1;
+		else if (strcmp(arg, "no") == 0 || strcmp(arg, "false") == 0)
+			value = 0;
+		else if (strcmp(arg, "ask") == 0)
+			value = 2;
+		else
+			fatal("%.200s line %d: Bad yes/no/ask argument.", filename, linenum);
+		if (*activep && *intptr == -1)
+			*intptr = value;
+		break;
+
+	case oCompression:
+		intptr = &options->compression;
+		goto parse_flag;
+
+	case oTCPKeepAlive:
+		intptr = &options->tcp_keep_alive;
+		goto parse_flag;
+
+	case oNoHostAuthenticationForLocalhost:
+		intptr = &options->no_host_authentication_for_localhost;
+		goto parse_flag;
+
+	case oNumberOfPasswordPrompts:
+		intptr = &options->number_of_password_prompts;
+		goto parse_int;
+
+	case oCompressionLevel:
+		intptr = &options->compression_level;
+		goto parse_int;
+
+	case oRekeyLimit:
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing argument.", filename, linenum);
+		if (arg[0] < '0' || arg[0] > '9')
+			fatal("%.200s line %d: Bad number.", filename, linenum);
+		orig = val64 = strtoll(arg, &endofnumber, 10);
+		if (arg == endofnumber)
+			fatal("%.200s line %d: Bad number.", filename, linenum);
+		switch (toupper(*endofnumber)) {
+		case '\0':
+			scale = 1;
+			break;
+		case 'K':
+			scale = 1<<10;
+			break;
+		case 'M':
+			scale = 1<<20;
+			break;
+		case 'G':
+			scale = 1<<30;
+			break;
+		default:
+			fatal("%.200s line %d: Invalid RekeyLimit suffix",
+			    filename, linenum);
+		}
+		val64 *= scale;
+		/* detect integer wrap and too-large limits */
+		if ((val64 / scale) != orig || val64 > UINT_MAX)
+			fatal("%.200s line %d: RekeyLimit too large",
+			    filename, linenum);
+		if (val64 < 16)
+			fatal("%.200s line %d: RekeyLimit too small",
+			    filename, linenum);
+		if (*activep && options->rekey_limit == -1)
+			options->rekey_limit = (u_int32_t)val64;
+		break;
+
+	case oIdentityFile:
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing argument.", filename, linenum);
+		if (*activep) {
+			intptr = &options->num_identity_files;
+			if (*intptr >= SSH_MAX_IDENTITY_FILES)
+				fatal("%.200s line %d: Too many identity files specified (max %d).",
+				    filename, linenum, SSH_MAX_IDENTITY_FILES);
+			charptr = &options->identity_files[*intptr];
+			*charptr = xstrdup(arg);
+			*intptr = *intptr + 1;
+		}
+		break;
+
+	case oXAuthLocation:
+		charptr=&options->xauth_location;
+		goto parse_string;
+
+	case oUser:
+		charptr = &options->user;
+parse_string:
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing argument.",
+			    filename, linenum);
+		if (*activep && *charptr == NULL)
+			*charptr = xstrdup(arg);
+		break;
+
+	case oGlobalKnownHostsFile:
+		cpptr = (char **)&options->system_hostfiles;
+		uintptr = &options->num_system_hostfiles;
+		max_entries = SSH_MAX_HOSTS_FILES;
+parse_char_array:
+		if (*activep && *uintptr == 0) {
+			while ((arg = strdelim(&s)) != NULL && *arg != '\0') {
+				if ((*uintptr) >= max_entries)
+					fatal("%s line %d: "
+					    "too many authorized keys files.",
+					    filename, linenum);
+				cpptr[(*uintptr)++] = xstrdup(arg);
+			}
+		}
+		return 0;
+
+	case oUserKnownHostsFile:
+		cpptr = (char **)&options->user_hostfiles;
+		uintptr = &options->num_user_hostfiles;
+		max_entries = SSH_MAX_HOSTS_FILES;
+		goto parse_char_array;
+
+	case oHostName:
+		charptr = &options->hostname;
+		goto parse_string;
+
+	case oHostKeyAlias:
+		charptr = &options->host_key_alias;
+		goto parse_string;
+
+	case oPreferredAuthentications:
+		charptr = &options->preferred_authentications;
+		goto parse_string;
+
+	case oBindAddress:
+		charptr = &options->bind_address;
+		goto parse_string;
+
+	case oPKCS11Provider:
+		charptr = &options->pkcs11_provider;
+		goto parse_string;
+
+	case oProxyCommand:
+		charptr = &options->proxy_command;
+parse_command:
+		if (s == NULL)
+			fatal("%.200s line %d: Missing argument.", filename, linenum);
+		len = strspn(s, WHITESPACE "=");
+		if (*activep && *charptr == NULL)
+			*charptr = xstrdup(s + len);
+		return 0;
+
+	case oPort:
+		intptr = &options->port;
+parse_int:
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing argument.", filename, linenum);
+		if (arg[0] < '0' || arg[0] > '9')
+			fatal("%.200s line %d: Bad number.", filename, linenum);
+
+		/* Octal, decimal, or hex format? */
+		value = strtol(arg, &endofnumber, 0);
+		if (arg == endofnumber)
+			fatal("%.200s line %d: Bad number.", filename, linenum);
+		if (*activep && *intptr == -1)
+			*intptr = value;
+		break;
+
+	case oConnectionAttempts:
+		intptr = &options->connection_attempts;
+		goto parse_int;
+
+	case oCipher:
+		intptr = &options->cipher;
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing argument.", filename, linenum);
+		value = cipher_number(arg);
+		if (value == -1)
+			fatal("%.200s line %d: Bad cipher '%s'.",
+			    filename, linenum, arg ? arg : "<NONE>");
+		if (*activep && *intptr == -1)
+			*intptr = value;
+		break;
+
+	case oCiphers:
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing argument.", filename, linenum);
+		if (!ciphers_valid(arg))
+			fatal("%.200s line %d: Bad SSH2 cipher spec '%s'.",
+			    filename, linenum, arg ? arg : "<NONE>");
+		if (*activep && options->ciphers == NULL)
+			options->ciphers = xstrdup(arg);
+		break;
+
+	case oMacs:
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing argument.", filename, linenum);
+		if (!mac_valid(arg))
+			fatal("%.200s line %d: Bad SSH2 Mac spec '%s'.",
+			    filename, linenum, arg ? arg : "<NONE>");
+		if (*activep && options->macs == NULL)
+			options->macs = xstrdup(arg);
+		break;
+
+	case oKexAlgorithms:
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing argument.",
+			    filename, linenum);
+		if (!kex_names_valid(arg))
+			fatal("%.200s line %d: Bad SSH2 KexAlgorithms '%s'.",
+			    filename, linenum, arg ? arg : "<NONE>");
+		if (*activep && options->kex_algorithms == NULL)
+			options->kex_algorithms = xstrdup(arg);
+		break;
+
+	case oHostKeyAlgorithms:
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing argument.", filename, linenum);
+		if (!key_names_valid2(arg))
+			fatal("%.200s line %d: Bad protocol 2 host key algorithms '%s'.",
+			    filename, linenum, arg ? arg : "<NONE>");
+		if (*activep && options->hostkeyalgorithms == NULL)
+			options->hostkeyalgorithms = xstrdup(arg);
+		break;
+
+	case oProtocol:
+		intptr = &options->protocol;
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing argument.", filename, linenum);
+		value = proto_spec(arg);
+		if (value == SSH_PROTO_UNKNOWN)
+			fatal("%.200s line %d: Bad protocol spec '%s'.",
+			    filename, linenum, arg ? arg : "<NONE>");
+		if (*activep && *intptr == SSH_PROTO_UNKNOWN)
+			*intptr = value;
+		break;
+
+	case oLogLevel:
+		log_level_ptr = &options->log_level;
+		arg = strdelim(&s);
+		value = log_level_number(arg);
+		if (value == SYSLOG_LEVEL_NOT_SET)
+			fatal("%.200s line %d: unsupported log level '%s'",
+			    filename, linenum, arg ? arg : "<NONE>");
+		if (*activep && *log_level_ptr == SYSLOG_LEVEL_NOT_SET)
+			*log_level_ptr = (LogLevel) value;
+		break;
+
+	case oLocalForward:
+	case oRemoteForward:
+	case oDynamicForward:
+		arg = strdelim(&s);
+		if (arg == NULL || *arg == '\0')
+			fatal("%.200s line %d: Missing port argument.",
+			    filename, linenum);
+
+		if (opcode == oLocalForward ||
+		    opcode == oRemoteForward) {
+			arg2 = strdelim(&s);
+			if (arg2 == NULL || *arg2 == '\0')
+				fatal("%.200s line %d: Missing target argument.",
+				    filename, linenum);
+
+			/* construct a string for parse_forward */
+			snprintf(fwdarg, sizeof(fwdarg), "%s:%s", arg, arg2);
+		} else if (opcode == oDynamicForward) {
+			strlcpy(fwdarg, arg, sizeof(fwdarg));
+		}
+
+		if (parse_forward(&fwd, fwdarg,
+		    opcode == oDynamicForward ? 1 : 0,
+		    opcode == oRemoteForward ? 1 : 0) == 0)
+			fatal("%.200s line %d: Bad forwarding specification.",
+			    filename, linenum);
+
+		if (*activep) {
+			if (opcode == oLocalForward ||
+			    opcode == oDynamicForward)
+				add_local_forward(options, &fwd);
+			else if (opcode == oRemoteForward)
+				add_remote_forward(options, &fwd);
+		}
+		break;
+
+	case oClearAllForwardings:
+		intptr = &options->clear_forwardings;
+		goto parse_flag;
+
+	case oHost:
+		*activep = 0;
+		arg2 = NULL;
+		while ((arg = strdelim(&s)) != NULL && *arg != '\0') {
+			negated = *arg == '!';
+			if (negated)
+				arg++;
+			if (match_pattern(host, arg)) {
+				if (negated) {
+					debug("%.200s line %d: Skipping Host "
+					    "block because of negated match "
+					    "for %.100s", filename, linenum,
+					    arg);
+					*activep = 0;
+					break;
+				}
+				if (!*activep)
+					arg2 = arg; /* logged below */
+				*activep = 1;
+			}
+		}
+		if (*activep)
+			debug("%.200s line %d: Applying options for %.100s",
+			    filename, linenum, arg2);
+		/* Avoid garbage check below, as strdelim is done. */
+		return 0;
+
+	case oEscapeChar:
+		intptr = &options->escape_char;
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing argument.", filename, linenum);
+		if (arg[0] == '^' && arg[2] == 0 &&
+		    (u_char) arg[1] >= 64 && (u_char) arg[1] < 128)
+			value = (u_char) arg[1] & 31;
+		else if (strlen(arg) == 1)
+			value = (u_char) arg[0];
+		else if (strcmp(arg, "none") == 0)
+			value = SSH_ESCAPECHAR_NONE;
+		else {
+			fatal("%.200s line %d: Bad escape character.",
+			    filename, linenum);
+			/* NOTREACHED */
+			value = 0;	/* Avoid compiler warning. */
+		}
+		if (*activep && *intptr == -1)
+			*intptr = value;
+		break;
+
+	case oAddressFamily:
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%s line %d: missing address family.",
+			    filename, linenum);
+		intptr = &options->address_family;
+		if (strcasecmp(arg, "inet") == 0)
+			value = AF_INET;
+		else if (strcasecmp(arg, "inet6") == 0)
+			value = AF_INET6;
+		else if (strcasecmp(arg, "any") == 0)
+			value = AF_UNSPEC;
+		else
+			fatal("Unsupported AddressFamily \"%s\"", arg);
+		if (*activep && *intptr == -1)
+			*intptr = value;
+		break;
+
+	case oEnableSSHKeysign:
+		intptr = &options->enable_ssh_keysign;
+		goto parse_flag;
+
+	case oIdentitiesOnly:
+		intptr = &options->identities_only;
+		goto parse_flag;
+
+	case oServerAliveInterval:
+		intptr = &options->server_alive_interval;
+		goto parse_time;
+
+	case oServerAliveCountMax:
+		intptr = &options->server_alive_count_max;
+		goto parse_int;
+
+	case oSendEnv:
+		while ((arg = strdelim(&s)) != NULL && *arg != '\0') {
+			if (strchr(arg, '=') != NULL)
+				fatal("%s line %d: Invalid environment name.",
+				    filename, linenum);
+			if (!*activep)
+				continue;
+			if (options->num_send_env >= MAX_SEND_ENV)
+				fatal("%s line %d: too many send env.",
+				    filename, linenum);
+			options->send_env[options->num_send_env++] =
+			    xstrdup(arg);
+		}
+		break;
+
+	case oControlPath:
+		charptr = &options->control_path;
+		goto parse_string;
+
+	case oControlMaster:
+		intptr = &options->control_master;
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing ControlMaster argument.",
+			    filename, linenum);
+		value = 0;	/* To avoid compiler warning... */
+		if (strcmp(arg, "yes") == 0 || strcmp(arg, "true") == 0)
+			value = SSHCTL_MASTER_YES;
+		else if (strcmp(arg, "no") == 0 || strcmp(arg, "false") == 0)
+			value = SSHCTL_MASTER_NO;
+		else if (strcmp(arg, "auto") == 0)
+			value = SSHCTL_MASTER_AUTO;
+		else if (strcmp(arg, "ask") == 0)
+			value = SSHCTL_MASTER_ASK;
+		else if (strcmp(arg, "autoask") == 0)
+			value = SSHCTL_MASTER_AUTO_ASK;
+		else
+			fatal("%.200s line %d: Bad ControlMaster argument.",
+			    filename, linenum);
+		if (*activep && *intptr == -1)
+			*intptr = value;
+		break;
+
+	case oControlPersist:
+		/* no/false/yes/true, or a time spec */
+		intptr = &options->control_persist;
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing ControlPersist"
+			    " argument.", filename, linenum);
+		value = 0;
+		value2 = 0;	/* timeout */
+		if (strcmp(arg, "no") == 0 || strcmp(arg, "false") == 0)
+			value = 0;
+		else if (strcmp(arg, "yes") == 0 || strcmp(arg, "true") == 0)
+			value = 1;
+		else if ((value2 = convtime(arg)) >= 0)
+			value = 1;
+		else
+			fatal("%.200s line %d: Bad ControlPersist argument.",
+			    filename, linenum);
+		if (*activep && *intptr == -1) {
+			*intptr = value;
+			options->control_persist_timeout = value2;
+		}
+		break;
+
+	case oHashKnownHosts:
+		intptr = &options->hash_known_hosts;
+		goto parse_flag;
+
+	case oTunnel:
+		intptr = &options->tun_open;
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%s line %d: Missing yes/point-to-point/"
+			    "ethernet/no argument.", filename, linenum);
+		value = 0;	/* silence compiler */
+		if (strcasecmp(arg, "ethernet") == 0)
+			value = SSH_TUNMODE_ETHERNET;
+		else if (strcasecmp(arg, "point-to-point") == 0)
+			value = SSH_TUNMODE_POINTOPOINT;
+		else if (strcasecmp(arg, "yes") == 0)
+			value = SSH_TUNMODE_DEFAULT;
+		else if (strcasecmp(arg, "no") == 0)
+			value = SSH_TUNMODE_NO;
+		else
+			fatal("%s line %d: Bad yes/point-to-point/ethernet/"
+			    "no argument: %s", filename, linenum, arg);
+		if (*activep)
+			*intptr = value;
+		break;
+
+	case oTunnelDevice:
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%.200s line %d: Missing argument.", filename, linenum);
+		value = a2tun(arg, &value2);
+		if (value == SSH_TUNID_ERR)
+			fatal("%.200s line %d: Bad tun device.", filename, linenum);
+		if (*activep) {
+			options->tun_local = value;
+			options->tun_remote = value2;
+		}
+		break;
+
+	case oLocalCommand:
+		charptr = &options->local_command;
+		goto parse_command;
+
+	case oPermitLocalCommand:
+		intptr = &options->permit_local_command;
+		goto parse_flag;
+
+	case oVisualHostKey:
+		intptr = &options->visual_host_key;
+		goto parse_flag;
+
+	case oIPQoS:
+		arg = strdelim(&s);
+		if ((value = parse_ipqos(arg)) == -1)
+			fatal("%s line %d: Bad IPQoS value: %s",
+			    filename, linenum, arg);
+		arg = strdelim(&s);
+		if (arg == NULL)
+			value2 = value;
+		else if ((value2 = parse_ipqos(arg)) == -1)
+			fatal("%s line %d: Bad IPQoS value: %s",
+			    filename, linenum, arg);
+		if (*activep) {
+			options->ip_qos_interactive = value;
+			options->ip_qos_bulk = value2;
+		}
+		break;
+
+	case oUseRoaming:
+		intptr = &options->use_roaming;
+		goto parse_flag;
+
+	case oRequestTTY:
+		arg = strdelim(&s);
+		if (!arg || *arg == '\0')
+			fatal("%s line %d: missing argument.",
+			    filename, linenum);
+		intptr = &options->request_tty;
+		if (strcasecmp(arg, "yes") == 0)
+			value = REQUEST_TTY_YES;
+		else if (strcasecmp(arg, "no") == 0)
+			value = REQUEST_TTY_NO;
+		else if (strcasecmp(arg, "force") == 0)
+			value = REQUEST_TTY_FORCE;
+		else if (strcasecmp(arg, "auto") == 0)
+			value = REQUEST_TTY_AUTO;
+		else
+			fatal("Unsupported RequestTTY \"%s\"", arg);
+		if (*activep && *intptr == -1)
+			*intptr = value;
+		break;
+
+	case oDeprecated:
+		debug("%s line %d: Deprecated option \"%s\"",
+		    filename, linenum, keyword);
+		return 0;
+
+	case oUnsupported:
+		error("%s line %d: Unsupported option \"%s\"",
+		    filename, linenum, keyword);
+		return 0;
+
+	default:
+		fatal("process_config_line: Unimplemented opcode %d", opcode);
+	}
+
+	/* Check that there is no garbage at end of line. */
+	if ((arg = strdelim(&s)) != NULL && *arg != '\0') {
+		fatal("%.200s line %d: garbage at end of line; \"%.200s\".",
+		    filename, linenum, arg);
+	}
+	return 0;
+}
+
+
+/*
+ * Reads the config file and modifies the options accordingly.  Options
+ * should already be initialized before this call.  This never returns if
+ * there is an error.  If the file does not exist, this returns 0.
+ */
+
+int
+read_config_file(const char *filename, const char *host, Options *options,
+    int checkperm)
+{
+	FILE *f;
+	char line[1024];
+	int active, linenum;
+	int bad_options = 0;
+
+	if ((f = fopen(filename, "r")) == NULL)
+		return 0;
+
+	if (checkperm) {
+		struct stat sb;
+
+		if (fstat(fileno(f), &sb) == -1)
+			fatal("fstat %s: %s", filename, strerror(errno));
+		if (((sb.st_uid != 0 && sb.st_uid != getuid()) ||
+		    (sb.st_mode & 022) != 0))
+			fatal("Bad owner or permissions on %s", filename);
+	}
+
+	debug("Reading configuration data %.200s", filename);
+
+	/*
+	 * Mark that we are now processing the options.  This flag is turned
+	 * on/off by Host specifications.
+	 */
+	active = 1;
+	linenum = 0;
+	while (fgets(line, sizeof(line), f)) {
+		/* Update line number counter. */
+		linenum++;
+		if (process_config_line(options, host, line, filename, linenum, &active) != 0)
+			bad_options++;
+	}
+	fclose(f);
+	if (bad_options > 0)
+		fatal("%s: terminating, %d bad configuration options",
+		    filename, bad_options);
+	return 1;
+}
+
+/*
+ * Initializes options to special values that indicate that they have not yet
+ * been set.  Read_config_file will only set options with this value. Options
+ * are processed in the following order: command line, user config file,
+ * system config file.  Last, fill_default_options is called.
+ */
+
+void
+initialize_options(Options * options)
+{
+	memset(options, 'X', sizeof(*options));
+	options->forward_agent = -1;
+	options->forward_x11 = -1;
+	options->forward_x11_trusted = -1;
+	options->forward_x11_timeout = -1;
+	options->exit_on_forward_failure = -1;
+	options->xauth_location = NULL;
+	options->gateway_ports = -1;
+	options->use_privileged_port = -1;
+	options->rsa_authentication = -1;
+	options->pubkey_authentication = -1;
+	options->challenge_response_authentication = -1;
+	options->gss_authentication = -1;
+	options->gss_deleg_creds = -1;
+	options->password_authentication = -1;
+	options->kbd_interactive_authentication = -1;
+	options->kbd_interactive_devices = NULL;
+	options->rhosts_rsa_authentication = -1;
+	options->hostbased_authentication = -1;
+	options->batch_mode = -1;
+	options->check_host_ip = -1;
+	options->strict_host_key_checking = -1;
+	options->compression = -1;
+	options->tcp_keep_alive = -1;
+	options->compression_level = -1;
+	options->port = -1;
+	options->address_family = -1;
+	options->connection_attempts = -1;
+	options->connection_timeout = -1;
+	options->number_of_password_prompts = -1;
+	options->cipher = -1;
+	options->ciphers = NULL;
+	options->macs = NULL;
+	options->kex_algorithms = NULL;
+	options->hostkeyalgorithms = NULL;
+	options->protocol = SSH_PROTO_UNKNOWN;
+	options->num_identity_files = 0;
+	options->hostname = NULL;
+	options->host_key_alias = NULL;
+	options->proxy_command = NULL;
+	options->user = NULL;
+	options->escape_char = -1;
+	options->num_system_hostfiles = 0;
+	options->num_user_hostfiles = 0;
+	options->local_forwards = NULL;
+	options->num_local_forwards = 0;
+	options->remote_forwards = NULL;
+	options->num_remote_forwards = 0;
+	options->clear_forwardings = -1;
+	options->log_level = SYSLOG_LEVEL_NOT_SET;
+	options->preferred_authentications = NULL;
+	options->bind_address = NULL;
+	options->pkcs11_provider = NULL;
+	options->enable_ssh_keysign = - 1;
+	options->no_host_authentication_for_localhost = - 1;
+	options->identities_only = - 1;
+	options->rekey_limit = - 1;
+	options->verify_host_key_dns = -1;
+	options->server_alive_interval = -1;
+	options->server_alive_count_max = -1;
+	options->num_send_env = 0;
+	options->control_path = NULL;
+	options->control_master = -1;
+	options->control_persist = -1;
+	options->control_persist_timeout = 0;
+	options->hash_known_hosts = -1;
+	options->tun_open = -1;
+	options->tun_local = -1;
+	options->tun_remote = -1;
+	options->local_command = NULL;
+	options->permit_local_command = -1;
+	options->use_roaming = -1;
+	options->visual_host_key = -1;
+	options->zero_knowledge_password_authentication = -1;
+	options->ip_qos_interactive = -1;
+	options->ip_qos_bulk = -1;
+	options->request_tty = -1;
+}
+
+/*
+ * Called after processing other sources of option data, this fills those
+ * options for which no value has been specified with their default values.
+ */
+
+void
+fill_default_options(Options * options)
+{
+	int len;
+
+	if (options->forward_agent == -1)
+		options->forward_agent = 0;
+	if (options->forward_x11 == -1)
+		options->forward_x11 = 0;
+	if (options->forward_x11_trusted == -1)
+		options->forward_x11_trusted = 0;
+	if (options->forward_x11_timeout == -1)
+		options->forward_x11_timeout = 1200;
+	if (options->exit_on_forward_failure == -1)
+		options->exit_on_forward_failure = 0;
+	if (options->xauth_location == NULL)
+		options->xauth_location = _PATH_XAUTH;
+	if (options->gateway_ports == -1)
+		options->gateway_ports = 0;
+	if (options->use_privileged_port == -1)
+		options->use_privileged_port = 0;
+	if (options->rsa_authentication == -1)
+		options->rsa_authentication = 1;
+	if (options->pubkey_authentication == -1)
+		options->pubkey_authentication = 1;
+	if (options->challenge_response_authentication == -1)
+		options->challenge_response_authentication = 1;
+	if (options->gss_authentication == -1)
+		options->gss_authentication = 0;
+	if (options->gss_deleg_creds == -1)
+		options->gss_deleg_creds = 0;
+	if (options->password_authentication == -1)
+		options->password_authentication = 1;
+	if (options->kbd_interactive_authentication == -1)
+		options->kbd_interactive_authentication = 1;
+	if (options->rhosts_rsa_authentication == -1)
+		options->rhosts_rsa_authentication = 0;
+	if (options->hostbased_authentication == -1)
+		options->hostbased_authentication = 0;
+	if (options->batch_mode == -1)
+		options->batch_mode = 0;
+	if (options->check_host_ip == -1)
+		options->check_host_ip = 1;
+	if (options->strict_host_key_checking == -1)
+		options->strict_host_key_checking = 2;	/* 2 is default */
+	if (options->compression == -1)
+		options->compression = 0;
+	if (options->tcp_keep_alive == -1)
+		options->tcp_keep_alive = 1;
+	if (options->compression_level == -1)
+		options->compression_level = 6;
+	if (options->port == -1)
+		options->port = 0;	/* Filled in ssh_connect. */
+	if (options->address_family == -1)
+		options->address_family = AF_UNSPEC;
+	if (options->connection_attempts == -1)
+		options->connection_attempts = 1;
+	if (options->number_of_password_prompts == -1)
+		options->number_of_password_prompts = 3;
+	/* Selected in ssh_login(). */
+	if (options->cipher == -1)
+		options->cipher = SSH_CIPHER_NOT_SET;
+	/* options->ciphers, default set in myproposals.h */
+	/* options->macs, default set in myproposals.h */
+	/* options->kex_algorithms, default set in myproposals.h */
+	/* options->hostkeyalgorithms, default set in myproposals.h */
+	if (options->protocol == SSH_PROTO_UNKNOWN)
+		options->protocol = SSH_PROTO_2;
+	if (options->num_identity_files == 0) {
+		if (options->protocol & SSH_PROTO_1) {
+			len = 2 + strlen(_PATH_SSH_CLIENT_IDENTITY) + 1;
+			options->identity_files[options->num_identity_files] =
+			    xmalloc(len);
+			snprintf(options->identity_files[options->num_identity_files++],
+			    len, "~/%.100s", _PATH_SSH_CLIENT_IDENTITY);
+		}
+		if (options->protocol & SSH_PROTO_2) {
+			len = 2 + strlen(_PATH_SSH_CLIENT_ID_RSA) + 1;
+			options->identity_files[options->num_identity_files] =
+			    xmalloc(len);
+			snprintf(options->identity_files[options->num_identity_files++],
+			    len, "~/%.100s", _PATH_SSH_CLIENT_ID_RSA);
+
+			len = 2 + strlen(_PATH_SSH_CLIENT_ID_DSA) + 1;
+			options->identity_files[options->num_identity_files] =
+			    xmalloc(len);
+			snprintf(options->identity_files[options->num_identity_files++],
+			    len, "~/%.100s", _PATH_SSH_CLIENT_ID_DSA);
+#ifdef OPENSSL_HAS_ECC
+			len = 2 + strlen(_PATH_SSH_CLIENT_ID_ECDSA) + 1;
+			options->identity_files[options->num_identity_files] =
+			    xmalloc(len);
+			snprintf(options->identity_files[options->num_identity_files++],
+			    len, "~/%.100s", _PATH_SSH_CLIENT_ID_ECDSA);
+#endif
+		}
+	}
+	if (options->escape_char == -1)
+		options->escape_char = '~';
+	if (options->num_system_hostfiles == 0) {
+		options->system_hostfiles[options->num_system_hostfiles++] =
+		    xstrdup(_PATH_SSH_SYSTEM_HOSTFILE);
+		options->system_hostfiles[options->num_system_hostfiles++] =
+		    xstrdup(_PATH_SSH_SYSTEM_HOSTFILE2);
+	}
+	if (options->num_user_hostfiles == 0) {
+		options->user_hostfiles[options->num_user_hostfiles++] =
+		    xstrdup(_PATH_SSH_USER_HOSTFILE);
+		options->user_hostfiles[options->num_user_hostfiles++] =
+		    xstrdup(_PATH_SSH_USER_HOSTFILE2);
+	}
+	if (options->log_level == SYSLOG_LEVEL_NOT_SET)
+		options->log_level = SYSLOG_LEVEL_INFO;
+	if (options->clear_forwardings == 1)
+		clear_forwardings(options);
+	if (options->no_host_authentication_for_localhost == - 1)
+		options->no_host_authentication_for_localhost = 0;
+	if (options->identities_only == -1)
+		options->identities_only = 0;
+	if (options->enable_ssh_keysign == -1)
+		options->enable_ssh_keysign = 0;
+	if (options->rekey_limit == -1)
+		options->rekey_limit = 0;
+	if (options->verify_host_key_dns == -1)
+		options->verify_host_key_dns = 0;
+	if (options->server_alive_interval == -1)
+		options->server_alive_interval = 0;
+	if (options->server_alive_count_max == -1)
+		options->server_alive_count_max = 3;
+	if (options->control_master == -1)
+		options->control_master = 0;
+	if (options->control_persist == -1) {
+		options->control_persist = 0;
+		options->control_persist_timeout = 0;
+	}
+	if (options->hash_known_hosts == -1)
+		options->hash_known_hosts = 0;
+	if (options->tun_open == -1)
+		options->tun_open = SSH_TUNMODE_NO;
+	if (options->tun_local == -1)
+		options->tun_local = SSH_TUNID_ANY;
+	if (options->tun_remote == -1)
+		options->tun_remote = SSH_TUNID_ANY;
+	if (options->permit_local_command == -1)
+		options->permit_local_command = 0;
+	if (options->use_roaming == -1)
+		options->use_roaming = 1;
+	if (options->visual_host_key == -1)
+		options->visual_host_key = 0;
+	if (options->zero_knowledge_password_authentication == -1)
+		options->zero_knowledge_password_authentication = 0;
+	if (options->ip_qos_interactive == -1)
+		options->ip_qos_interactive = IPTOS_LOWDELAY;
+	if (options->ip_qos_bulk == -1)
+		options->ip_qos_bulk = IPTOS_THROUGHPUT;
+	if (options->request_tty == -1)
+		options->request_tty = REQUEST_TTY_AUTO;
+	/* options->local_command should not be set by default */
+	/* options->proxy_command should not be set by default */
+	/* options->user will be set in the main program if appropriate */
+	/* options->hostname will be set in the main program if appropriate */
+	/* options->host_key_alias should not be set by default */
+	/* options->preferred_authentications will be set in ssh */
+}
+
+/*
+ * parse_forward
+ * parses a string containing a port forwarding specification of the form:
+ *   dynamicfwd == 0
+ *	[listenhost:]listenport:connecthost:connectport
+ *   dynamicfwd == 1
+ *	[listenhost:]listenport
+ * returns number of arguments parsed or zero on error
+ */
+int
+parse_forward(Forward *fwd, const char *fwdspec, int dynamicfwd, int remotefwd)
+{
+	int i;
+	char *p, *cp, *fwdarg[4];
+
+	memset(fwd, '\0', sizeof(*fwd));
+
+	cp = p = xstrdup(fwdspec);
+
+	/* skip leading spaces */
+	while (isspace(*cp))
+		cp++;
+
+	for (i = 0; i < 4; ++i)
+		if ((fwdarg[i] = hpdelim(&cp)) == NULL)
+			break;
+
+	/* Check for trailing garbage */
+	if (cp != NULL)
+		i = 0;	/* failure */
+
+	switch (i) {
+	case 1:
+		fwd->listen_host = NULL;
+		fwd->listen_port = a2port(fwdarg[0]);
+		fwd->connect_host = xstrdup("socks");
+		break;
+
+	case 2:
+		fwd->listen_host = xstrdup(cleanhostname(fwdarg[0]));
+		fwd->listen_port = a2port(fwdarg[1]);
+		fwd->connect_host = xstrdup("socks");
+		break;
+
+	case 3:
+		fwd->listen_host = NULL;
+		fwd->listen_port = a2port(fwdarg[0]);
+		fwd->connect_host = xstrdup(cleanhostname(fwdarg[1]));
+		fwd->connect_port = a2port(fwdarg[2]);
+		break;
+
+	case 4:
+		fwd->listen_host = xstrdup(cleanhostname(fwdarg[0]));
+		fwd->listen_port = a2port(fwdarg[1]);
+		fwd->connect_host = xstrdup(cleanhostname(fwdarg[2]));
+		fwd->connect_port = a2port(fwdarg[3]);
+		break;
+	default:
+		i = 0; /* failure */
+	}
+
+	xfree(p);
+
+	if (dynamicfwd) {
+		if (!(i == 1 || i == 2))
+			goto fail_free;
+	} else {
+		if (!(i == 3 || i == 4))
+			goto fail_free;
+		if (fwd->connect_port <= 0)
+			goto fail_free;
+	}
+
+	if (fwd->listen_port < 0 || (!remotefwd && fwd->listen_port == 0))
+		goto fail_free;
+
+	if (fwd->connect_host != NULL &&
+	    strlen(fwd->connect_host) >= NI_MAXHOST)
+		goto fail_free;
+	if (fwd->listen_host != NULL &&
+	    strlen(fwd->listen_host) >= NI_MAXHOST)
+		goto fail_free;
+
+
+	return (i);
+
+ fail_free:
+	if (fwd->connect_host != NULL) {
+		xfree(fwd->connect_host);
+		fwd->connect_host = NULL;
+	}
+	if (fwd->listen_host != NULL) {
+		xfree(fwd->listen_host);
+		fwd->listen_host = NULL;
+	}
+	return (0);
+}