libssh/common/readconf.c

/*
 * 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".
 */
/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include "includes.h"
RCSID("$OpenBSD: readconf.c,v 1.100 2002/06/19 00:27:55 deraadt Exp $");

#pragma ident	"%Z%%M%	%I%	%E% SMI"

#include "ssh.h"
#include "xmalloc.h"
#include "compat.h"
#include "cipher.h"
#include "pathnames.h"
#include "log.h"
#include "readconf.h"
#include "match.h"
#include "misc.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
     RhostsAuthentication no
     PasswordAuthentication no

   Host puukko.hut.fi
     User t35124p
     ProxyCommand ssh-proxy %h %p

   Host *.fr
     PublicKeyAuthentication no

   Host *.su
     Cipher none
     PasswordAuthentication no

   # Defaults for various options
   Host *
     ForwardAgent no
     ForwardX11 no
     RhostsAuthentication yes
     PasswordAuthentication yes
     RSAAuthentication yes
     RhostsRSAAuthentication yes
     StrictHostKeyChecking yes
     KeepAlives no
     IdentityFile ~/.ssh/identity
     Port 22
     EscapeChar ~

*/

/* Keyword tokens. */

typedef enum {
	oBadOption,
	oForwardAgent, oForwardX11, oForwardX11Trusted, oGatewayPorts,
	oRhostsAuthentication,
	oPasswordAuthentication, oRSAAuthentication,
	oChallengeResponseAuthentication, oXAuthLocation,
#if defined(KRB4) || defined(KRB5)
	oKerberosAuthentication,
#endif
#ifdef GSSAPI
	oGssKeyEx, oGssAuthentication, oGssDelegateCreds,
#ifdef GSI
	oGssGlobusDelegateLimitedCreds,
#endif /* GSI */
#endif /* GSSAPI */
#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, oKeepAlives, oNumberOfPasswordPrompts,
	oUsePrivilegedPort, oLogLevel, oCiphers, oProtocol, oMacs,
	oGlobalKnownHostsFile2, oUserKnownHostsFile2, oPubkeyAuthentication,
	oKbdInteractiveAuthentication, oKbdInteractiveDevices, oHostKeyAlias,
	oDynamicForward, oPreferredAuthentications, oHostbasedAuthentication,
	oHostKeyAlgorithms, oBindAddress, oSmartcardDevice,
	oClearAllForwardings, oNoHostAuthenticationForLocalhost,
	oFallBackToRsh, oUseRsh, oConnectTimeout, oHashKnownHosts,
	oServerAliveInterval, oServerAliveCountMax, oDisableBanner,
	oIgnoreIfUnknown, oRekeyLimit,
	oDeprecated
} OpCodes;

/* Textual representations of the tokens. */

static struct {
	const char *name;
	OpCodes opcode;
} keywords[] = {
	{ "forwardagent", oForwardAgent },
	{ "forwardx11", oForwardX11 },
	{ "forwardx11trusted", oForwardX11Trusted },
	{ "xauthlocation", oXAuthLocation },
	{ "gatewayports", oGatewayPorts },
	{ "useprivilegedport", oUsePrivilegedPort },
	{ "rhostsauthentication", oRhostsAuthentication },
	{ "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
#ifdef GSSAPI
	{ "gssapikeyexchange", oGssKeyEx },
	{ "gssapiauthentication", oGssAuthentication },
	{ "gssapidelegatecredentials", oGssDelegateCreds },
	{ "gsskeyex", oGssKeyEx },				/* alias */
	{ "gssauthentication", oGssAuthentication },		/* alias */
	{ "gssdelegatecreds", oGssDelegateCreds },		/* alias */
#ifdef GSI
	/* For backwards compatability with old 1.2.27 client code */
	{ "forwardgssapiglobusproxy", oGssDelegateCreds }, /* alias */
	{ "forwardgssapiglobuslimitedproxy", oGssGlobusDelegateLimitedCreds },
#endif /* GSI */
#endif /* GSSAPI */
#if defined(AFS) || defined(KRB5)
	{ "kerberostgtpassing", oKerberosTgtPassing },
#endif
#ifdef AFS
	{ "afstokenpassing", oAFSTokenPassing },
#endif
	{ "fallbacktorsh", oFallBackToRsh },
	{ "usersh", oUseRsh },
	{ "identityfile", oIdentityFile },
	{ "identityfile2", oIdentityFile },			/* alias */
	{ "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 },
	{ "userknownhostsfile", oUserKnownHostsFile },		/* obsolete */
	{ "globalknownhostsfile2", oGlobalKnownHostsFile2 },
	{ "userknownhostsfile2", oUserKnownHostsFile2 },	/* obsolete */
	{ "connectionattempts", oConnectionAttempts },
	{ "batchmode", oBatchMode },
	{ "checkhostip", oCheckHostIP },
	{ "stricthostkeychecking", oStrictHostKeyChecking },
	{ "compression", oCompression },
	{ "compressionlevel", oCompressionLevel },
	{ "keepalive", oKeepAlives },
	{ "numberofpasswordprompts", oNumberOfPasswordPrompts },
	{ "loglevel", oLogLevel },
	{ "dynamicforward", oDynamicForward },
	{ "preferredauthentications", oPreferredAuthentications },
	{ "hostkeyalgorithms", oHostKeyAlgorithms },
	{ "bindaddress", oBindAddress },
	{ "smartcarddevice", oSmartcardDevice },
	{ "clearallforwardings", oClearAllForwardings },
	{ "nohostauthenticationforlocalhost", oNoHostAuthenticationForLocalhost },
	{ "rekeylimit", oRekeyLimit },
	{ "connecttimeout", oConnectTimeout },
	{ "serveraliveinterval", oServerAliveInterval },
	{ "serveralivecountmax", oServerAliveCountMax },
	{ "disablebanner", oDisableBanner },
	{ "hashknownhosts", oHashKnownHosts },
	{ "ignoreifunknown", oIgnoreIfUnknown },
	{ 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
	if (options->num_local_forwards >= SSH_MAX_FORWARDS_PER_DIRECTION)
		fatal("Too many local forwards (max %d).", SSH_MAX_FORWARDS_PER_DIRECTION);
	fwd = &options->local_forwards[options->num_local_forwards++];

	fwd->listen_host = (newfwd->listen_host == NULL) ?
	    NULL : xstrdup(newfwd->listen_host);
	fwd->listen_port = newfwd->listen_port;
	fwd->connect_host = xstrdup(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;
	if (options->num_remote_forwards >= SSH_MAX_FORWARDS_PER_DIRECTION)
		fatal("Too many remote forwards (max %d).",
		    SSH_MAX_FORWARDS_PER_DIRECTION);
	fwd = &options->remote_forwards[options->num_remote_forwards++];

	fwd->listen_host = (newfwd->listen_host == NULL) ?
	    NULL : xstrdup(newfwd->listen_host);
	fwd->listen_port = newfwd->listen_port;
	fwd->connect_host = xstrdup(newfwd->connect_host);
	fwd->connect_port = newfwd->connect_port;
}

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);
	}
	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);
	}
	options->num_remote_forwards = 0;
}

/*
 * 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;

	debug("%s: line %d: unknown 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.
 */

int
process_config_line(Options *options, const char *host,
		    char *line, const char *filename, int linenum,
		    int *activep)
{
	char *s, *string, **charptr, *endofnumber, *keyword, *arg, *arg2, fwdarg[256];
	int opcode, *intptr, value, scale, i;
	long long orig, val64;
	StoredOption *so;
	Forward fwd;

	s = line;
	/* Get the keyword. (Each line is supposed to begin with a keyword). */
	keyword = strdelim(&s);
	/* 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:
		if (options->unknown_opts_num == MAX_UNKNOWN_OPTIONS) {
			error("we can't have more than %d unknown options:",
			    MAX_UNKNOWN_OPTIONS);
			for (i = 0; i < MAX_UNKNOWN_OPTIONS; ++i) {
				so = &options->unknown_opts[i];
				error("%s:%d:%s",
				    so->filename, so->linenum, so->keyword);
				xfree(so->keyword);
				xfree(so->filename);
			}
			fatal("too many unknown options found, can't continue");
		}

		/* unknown options will be processed later */
		so = &options->unknown_opts[options->unknown_opts_num];
		so->keyword = xstrdup(keyword);
		so->filename = xstrdup(filename);
		so->linenum = linenum;
		options->unknown_opts_num++;
		return (0);

		/* 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 oGatewayPorts:
		intptr = &options->gateway_ports;
		goto parse_flag;

	case oUsePrivilegedPort:
		intptr = &options->use_privileged_port;
		goto parse_flag;

	case oRhostsAuthentication:
		intptr = &options->rhosts_authentication;
		goto parse_flag;

	case oPasswordAuthentication:
		intptr = &options->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
#ifdef GSSAPI
	case oGssKeyEx:
		intptr = &options->gss_keyex;
		goto parse_flag;

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

	case oGssDelegateCreds:
		intptr = &options->gss_deleg_creds;
		goto parse_flag;

#ifdef GSI
	case oGssGlobusDelegateLimitedCreds:
		intptr = &options->gss_globus_deleg_limited_proxy;
		goto parse_flag;
#endif /* GSI */

#endif /* GSSAPI */

#if defined(AFS) || defined(KRB5)
	case oKerberosTgtPassing:
		intptr = &options->kerberos_tgt_passing;
		goto parse_flag;
#endif
#ifdef AFS
	case oAFSTokenPassing:
		intptr = &options->afs_token_passing;
		goto parse_flag;
#endif
	case oFallBackToRsh:
		intptr = &options->fallback_to_rsh;
		goto parse_flag;

	case oUseRsh:
		intptr = &options->use_rsh;
		goto parse_flag;

	case oBatchMode:
		intptr = &options->batch_mode;
		goto parse_flag;

	case oCheckHostIP:
		intptr = &options->check_host_ip;
		goto parse_flag;

	case oStrictHostKeyChecking:
		intptr = &options->strict_host_key_checking;
		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 oKeepAlives:
		intptr = &options->keepalives;
		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:
		charptr = &options->system_hostfile;
		goto parse_string;

	case oUserKnownHostsFile:
		charptr = &options->user_hostfile;
		goto parse_string;

	case oGlobalKnownHostsFile2:
		charptr = &options->system_hostfile2;
		goto parse_string;

	case oUserKnownHostsFile2:
		charptr = &options->user_hostfile2;
		goto parse_string;

	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 oSmartcardDevice:
		charptr = &options->smartcard_device;
		goto parse_string;

	case oProxyCommand:
		charptr = &options->proxy_command;
		string = xstrdup("");
		while ((arg = strdelim(&s)) != NULL && *arg != '\0') {
			string = xrealloc(string, strlen(string) + strlen(arg) + 2);
			strcat(string, " ");
			strcat(string, arg);
		}
		if (*activep && *charptr == NULL)
			*charptr = string;
		else
			xfree(string);
		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 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:
		intptr = (int *) &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 && (LogLevel) *intptr == SYSLOG_LEVEL_NOT_SET)
			*intptr = (LogLevel) value;
		break;

	case oLocalForward:
	case oRemoteForward:
		arg = strdelim(&s);
		if (arg == NULL || *arg == '\0')
			fatal("%.200s line %d: Missing port argument.",
			    filename, linenum);
		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);

		if (parse_forward(1, &fwd, fwdarg) == 0)
			fatal("%.200s line %d: Bad forwarding specification.",
			    filename, linenum);

		if (*activep) {
			if (opcode == oLocalForward)
				add_local_forward(options, &fwd);
			else if (opcode == oRemoteForward)
				add_remote_forward(options, &fwd);
		}
		break;

	case oDynamicForward:
		arg = strdelim(&s);
		if (!arg || *arg == '\0')
			fatal("%.200s line %d: Missing port argument.",
			    filename, linenum);

		if (parse_forward(0, &fwd, arg) == 0) {
			fatal("%.200s line %d: Bad dynamic forwarding specification.",
			    filename, linenum);
		}

		if (*activep) {
			fwd.connect_host = "socks";
			add_local_forward(options, &fwd);
		}
		break;

	case oClearAllForwardings:
		intptr = &options->clear_forwardings;
		goto parse_flag;

	case oHost:
		*activep = 0;
		while ((arg = strdelim(&s)) != NULL && *arg != '\0')
			if (match_pattern(host, arg)) {
				debug("Applying options for %.100s", arg);
				*activep = 1;
				break;
			}
		/* 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 oServerAliveInterval:
		intptr = &options->server_alive_interval;
		goto parse_time;

	case oServerAliveCountMax:
		intptr = &options->server_alive_count_max;
		goto parse_int;

	case oHashKnownHosts:
		intptr = &options->hash_known_hosts;
		goto parse_flag;

	case oDisableBanner:
		arg = strdelim(&s);
		if (get_yes_no_flag(&options->disable_banner, arg, filename,
		    linenum, *activep) == 1)
			break;

		if (strcmp(arg, "in-exec-mode") == 0)
			options->disable_banner = SSH_NO_BANNER_IN_EXEC_MODE;
		else
			fatal("%.200s line %d: Bad yes/no/in-exec-mode "
			    "argument.", filename, linenum);
		break;

	case oIgnoreIfUnknown:
		charptr = &options->ignore_if_unknown;
		goto parse_string;

	case oDeprecated:
		debug("%s line %d: Deprecated 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)
{
	FILE *f;
	char line[1024];
	int active, linenum;

	/* Open the file. */
	f = fopen(filename, "r");
	if (!f)
		return 0;

	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++;
		process_config_line(options, host, line, filename, linenum, &active);
	}
	fclose(f);
	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->xauth_location = NULL;
	options->gateway_ports = -1;
	options->use_privileged_port = -1;
	options->rhosts_authentication = -1;
	options->rsa_authentication = -1;
	options->pubkey_authentication = -1;
	options->challenge_response_authentication = -1;
#ifdef GSSAPI
        options->gss_keyex = -1;
        options->gss_authentication = -1;
        options->gss_deleg_creds = -1;
#ifdef GSI
        options->gss_globus_deleg_limited_proxy = -1;
#endif /* GSI */
#endif /* GSSAPI */

#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->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->keepalives = -1;
	options->compression_level = -1;
	options->port = -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->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->system_hostfile = NULL;
	options->user_hostfile = NULL;
	options->system_hostfile2 = NULL;
	options->user_hostfile2 = NULL;
	options->num_local_forwards = 0;
	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->smartcard_device = NULL;
	options->no_host_authentication_for_localhost = -1;
	options->rekey_limit = -1;
	options->fallback_to_rsh = -1;
	options->use_rsh = -1;
	options->server_alive_interval = -1;
	options->server_alive_count_max = -1;
	options->hash_known_hosts = -1;
	options->ignore_if_unknown = NULL;
	options->unknown_opts_num = 0;
	options->disable_banner = -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;
	/*
	 * Unlike OpenSSH, we keep backward compatibility for '-X' option
	 * which means that X11 forwarding is trusted by default.
	 */
	if (options->forward_x11_trusted == -1)
		options->forward_x11_trusted = 1;
	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->rhosts_authentication == -1)
		options->rhosts_authentication = 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;
#ifdef GSSAPI
	if (options->gss_keyex == -1)
		options->gss_keyex = 1;
	if (options->gss_authentication == -1)
		options->gss_authentication = 1;
	if (options->gss_deleg_creds == -1)
		options->gss_deleg_creds = 0;
#ifdef GSI
	if (options->gss_globus_deleg_limited_proxy == -1)
		options->gss_globus_deleg_limited_proxy = 0;
#endif /* GSI */
#endif /* GSSAPI */
#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->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->keepalives == -1)
		options->keepalives = 1;
	if (options->compression_level == -1)
		options->compression_level = 6;
	if (options->port == -1)
		options->port = 0;	/* Filled in ssh_connect. */
	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->hostkeyalgorithms, default set in myproposals.h */
	if (options->protocol == SSH_PROTO_UNKNOWN)
		options->protocol = SSH_PROTO_1|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);
		}
	}
	if (options->escape_char == -1)
		options->escape_char = '~';
	if (options->system_hostfile == NULL)
		options->system_hostfile = _PATH_SSH_SYSTEM_HOSTFILE;
	if (options->user_hostfile == NULL)
		options->user_hostfile = _PATH_SSH_USER_HOSTFILE;
	if (options->system_hostfile2 == NULL)
		options->system_hostfile2 = _PATH_SSH_SYSTEM_HOSTFILE2;
	if (options->user_hostfile2 == NULL)
		options->user_hostfile2 = _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->rekey_limit == -1)
		options->rekey_limit = 0;
	if (options->fallback_to_rsh == -1)
		options->fallback_to_rsh = 0;
	if (options->use_rsh == -1)
		options->use_rsh = 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->hash_known_hosts == -1)
		options->hash_known_hosts = 0;
	if (options->disable_banner == -1)
		options->disable_banner = 0;
	/* 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 */
	/* options->ignore_if_unknown should not be set by default */
}

/*
 * Parses a string containing a port forwarding specification of one of the
 * two forms, short or long:
 *
 *	[listenhost:]listenport
 *	[listenhost:]listenport:connecthost:connectport
 *
 * short forwarding specification is used for dynamic port forwarding and for
 * port forwarding cancelation in process_cmdline(). The function returns number
 * of arguments parsed or zero on any error.
 */
int
parse_forward(int long_form, Forward *fwd, const char *fwdspec)
{
	int i;
	char *p, *cp, *fwdarg[5];

	memset(fwd, '\0', sizeof(*fwd));

	cp = p = xstrdup(fwdspec);

	/* skip leading spaces */
	while (isspace(*cp))
		cp++;

	for (i = 0; i < 5; ++i)
		if ((fwdarg[i] = hpdelim(&cp)) == NULL)
			break;

	if ((long_form == 0 && i > 2) || (long_form == 1 && i < 3) || (i == 5))
		goto fail_free;

	switch (i) {
	case 0:
		goto fail_free;

	case 1:
		fwd->listen_host = NULL;
		fwd->listen_port = a2port(fwdarg[0]);
		break;

	case 2:
		fwd->listen_host = xstrdup(cleanhostname(fwdarg[0]));
		fwd->listen_port = a2port(fwdarg[1]);
		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;
	}

	xfree(p);

	if (fwd->listen_port == 0 || (fwd->connect_port == 0 && i > 2))
		goto fail_free;

	return (i);

 fail_free:
	if (p != NULL)
		xfree(p);
	if (fwd->connect_host != NULL)
		xfree(fwd->connect_host);
	if (fwd->listen_host != NULL)
		xfree(fwd->listen_host);
	return (0);
}

/*
 * Process previously stored unknown options. When this function is called we
 * already have IgnoreIfUnknown set so finally we can decide whether each
 * unknown option is to be ignored or not.
 */
void
process_unknown_options(Options *options)
{
	StoredOption *so;
	int m, i, bad_options = 0;

	/* if there is no unknown option we are done */
	if (options->unknown_opts_num == 0)
		return;

	/*
	 * Now go through the list of unknown options and report any one that
	 * is not explicitly listed in IgnoreIfUnknown option. If at least one
	 * such as that is found it's a show stopper.
	 */
	for (i = 0; i < options->unknown_opts_num; ++i) {
		so = &options->unknown_opts[i];
		if (options->ignore_if_unknown == NULL)
			m = 0;
		else
			m = match_pattern_list(tolowercase(so->keyword),
			    options->ignore_if_unknown,
			    strlen(options->ignore_if_unknown), 1);
		if (m == 1) {
			debug("%s: line %d: ignoring unknown option: %s",
			    so->filename, so->linenum, so->keyword);
		}
		else {
			error("%s: line %d: unknown configuration option: %s",
			    so->filename, so->linenum, so->keyword);
			bad_options++;
		}
		xfree(so->keyword);
		xfree(so->filename);
	}

	/* exit if we found at least one unignored unknown option */
	if (bad_options > 0)
		fatal("terminating, %d bad configuration option(s)",
		    bad_options);
}