xref: /src/crypto/external/bsd/openssh/dist/readconf.c

/*	$NetBSD: readconf.c,v 1.7 2012/04/27 15:45:37 tls Exp $	*/
/* $OpenBSD: readconf.c,v 1.193 2011/05/24 07:15:47 djm Exp $ */
/*
 * Author: Tatu Ylonen <ylo (at) cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo (at) 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"
__RCSID("$NetBSD: readconf.c,v 1.7 2012/04/27 15:45:37 tls Exp $");
#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 <stdio.h>
#include <string.h>
#include <unistd.h>
#include <limits.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,
#if defined(KRB4) || defined(KRB5)
	oKerberosAuthentication,
#endif
#if defined(AFS) || defined(KRB5)
	oKerberosTgtPassing,
#endif
#ifdef AFS
	oAFSTokenPassing,
#endif
	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,
	oNoneEnabled, oTcpRcvBufPoll, oTcpRcvBuf, oNoneSwitch, oHPNDisabled,
	oHPNBufferSize,
	oSendVersionFirst,
	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 */
#if defined(KRB4) || defined(KRB5)
	{ "kerberosauthentication", oKerberosAuthentication },
#endif
#if defined(AFS) || defined(KRB5)
	{ "kerberostgtpassing", oKerberosTgtPassing },
	{ "kerberos5tgtpassing", oKerberosTgtPassing },		/* alias */
	{ "kerberos4tgtpassing", oKerberosTgtPassing },		/* alias */
#endif
#ifdef AFS
	{ "afstokenpassing", oAFSTokenPassing },
#endif
#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 },
	{ "noneenabled", oNoneEnabled },
	{ "tcprcvbufpoll", oTcpRcvBufPoll },
	{ "tcprcvbuf", oTcpRcvBuf },
	{ "noneswitch", oNoneSwitch },
	{ "hpndisabled", oHPNDisabled },
	{ "hpnbuffersize", oHPNBufferSize },
	{ "sendversionfirst", oSendVersionFirst },

	{ 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;
	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.");
	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;

#if defined(KRB4) || defined(KRB5)
	case oKerberosAuthentication:
		intptr = &options->kerberos_authentication;
		goto parse_flag;
#endif
#if defined(AFS) || defined(KRB5)
	case oKerberosTgtPassing:
		intptr = &options->kerberos_tgt_passing;
		goto parse_flag;
#endif

	case oGssAuthentication:
		intptr = &options->gss_authentication;
		goto parse_flag;

#ifdef AFS
	case oAFSTokenPassing:
		intptr = &options->afs_token_passing;
 		goto parse_flag;
#endif

	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 oNoneEnabled:
		intptr = &options->none_enabled;
		goto parse_flag;

	/* we check to see if the command comes from the */
	/* command line or not. If it does then enable it */
	/* otherwise fail. NONE should never be a default configuration */
	case oNoneSwitch:
		if(strcmp(filename,"command-line")==0)
		{
		    intptr = &options->none_switch;
		    goto parse_flag;
		} else {
		    error("NoneSwitch is found in %.200s.\nYou may only use this configuration option from the command line", filename);
		    error("Continuing...");
		    debug("NoneSwitch directive found in %.200s.", filename);
		    return 0;
	        }

	case oHPNDisabled:
		intptr = &options->hpn_disabled;
		goto parse_flag;

	case oHPNBufferSize:
		intptr = &options->hpn_buffer_size;
		goto parse_int;

	case oTcpRcvBufPoll:
		intptr = &options->tcp_rcv_buf_poll;
		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((unsigned char)*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:
			scale = 0;
			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 oTcpRcvBuf:
		intptr = &options->tcp_rcv_buf;
		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);
		value = 0;	/* To avoid compiler warning... */
		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;
		value = 0;	/* To avoid compiler warning... */
		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 oSendVersionFirst:
		intptr = &options->send_version_first;
		goto parse_flag;

	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;
#if defined(KRB4) || defined(KRB5)
	options->kerberos_authentication = -1;
#endif
#if defined(AFS) || defined(KRB5)
	options->kerberos_tgt_passing = -1;
#endif
#ifdef AFS
	options->afs_token_passing = -1;
#endif
	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;
	options->none_switch = -1;
	options->none_enabled = -1;
	options->hpn_disabled = -1;
	options->hpn_buffer_size = -1;
	options->tcp_rcv_buf_poll = -1;
	options->tcp_rcv_buf = -1;
	options->send_version_first = -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 = __UNCONST(_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 defined(KRB4) || defined(KRB5)
	if (options->kerberos_authentication == -1)
		options->kerberos_authentication = 1;
#endif
#if defined(AFS) || defined(KRB5)
	if (options->kerberos_tgt_passing == -1)
		options->kerberos_tgt_passing = 1;
#endif
#ifdef AFS
	if (options->afs_token_passing == -1)
		options->afs_token_passing = 1;
#endif
	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);

			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);
		}
	}
	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->none_switch == -1)
	        options->none_switch = 0;
	if (options->hpn_disabled == -1)
	        options->hpn_disabled = 0;
	if (options->hpn_buffer_size > -1)
	{
	  /* if a user tries to set the size to 0 set it to 1KB */
		if (options->hpn_buffer_size == 0)
		options->hpn_buffer_size = 1024;
		/*limit the buffer to 64MB*/
		if (options->hpn_buffer_size > 65536)
		{
			options->hpn_buffer_size = 65536*1024;
			debug("User requested buffer larger than 64MB. Request reverted to 64MB");
		}
		debug("hpn_buffer_size set to %d", options->hpn_buffer_size);
	}
	if (options->tcp_rcv_buf == 0)
		options->tcp_rcv_buf = 1;
	if (options->tcp_rcv_buf > -1)
		options->tcp_rcv_buf *=1024;
	if (options->tcp_rcv_buf_poll == -1)
		options->tcp_rcv_buf_poll = 1;
	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;
	if (options->send_version_first == -1)
		options->send_version_first = 1;
	/* 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((unsigned char)*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);
}