auth-options.c - security/openssh-library - Rivoreo Source Code Repositories

 /* $OpenBSD: auth-options.c,v 1.59 2013/07/12 00:19:58 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
  *                    All rights reserved
  * 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 <netdb.h>
 #include <pwd.h>
 #include <string.h>
 #include <stdio.h>
 #include <stdarg.h>

 #include "openbsd-compat/sys-queue.h"
 #include "xmalloc.h"
 #include "match.h"
 #include "log.h"
 #include "canohost.h"
 #include "buffer.h"
 #include "channels.h"
 #include "servconf.h"
 #include "misc.h"
 #include "key.h"
 #include "auth-options.h"
 #include "hostfile.h"
 #include "auth.h"
 #ifdef GSSAPI
 #include "ssh-gss.h"
 #endif
 #include "monitor_wrap.h"

 /* Flags set authorized_keys flags */
 int no_port_forwarding_flag = 0;
 int no_agent_forwarding_flag = 0;
 int no_x11_forwarding_flag = 0;
 int no_pty_flag = 0;
 int no_user_rc = 0;
 int key_is_cert_authority = 0;

 /* "command=" option. */
 char *forced_command = NULL;

 /* "environment=" options. */
 struct envstring *custom_environment = NULL;

 /* "tunnel=" option. */
 int forced_tun_device = -1;

 /* "principals=" option. */
 char *authorized_principals = NULL;

 extern ServerOptions options;

 void
 auth_clear_options(void)
 {
 	no_agent_forwarding_flag = 0;
 	no_port_forwarding_flag = 0;
 	no_pty_flag = 0;
 	no_x11_forwarding_flag = 0;
 	no_user_rc = 0;
 	key_is_cert_authority = 0;
 	while (custom_environment) {
 		struct envstring *ce = custom_environment;
 		custom_environment = ce->next;
 		free(ce->s);
 		free(ce);
 	}
 	if (forced_command) {
 		free(forced_command);
 		forced_command = NULL;
 	}
 	if (authorized_principals) {
 		free(authorized_principals);
 		authorized_principals = NULL;
 	}
 	forced_tun_device = -1;
 	channel_clear_permitted_opens();
 }

 /*
  * return 1 if access is granted, 0 if not.
  * side effect: sets key option flags
  */
 int
 auth_parse_options(struct passwd *pw, char *opts, char *file, u_long linenum)
 {
 	const char *cp;
 	int i;

 	/* reset options */
 	auth_clear_options();

 	if (!opts)
 		return 1;

 	while (*opts && *opts != ' ' && *opts != '\t') {
 		cp = "cert-authority";
 		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
 			key_is_cert_authority = 1;
 			opts += strlen(cp);
 			goto next_option;
 		}
 		cp = "no-port-forwarding";
 		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
 			auth_debug_add("Port forwarding disabled.");
 			no_port_forwarding_flag = 1;
 			opts += strlen(cp);
 			goto next_option;
 		}
 		cp = "no-agent-forwarding";
 		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
 			auth_debug_add("Agent forwarding disabled.");
 			no_agent_forwarding_flag = 1;
 			opts += strlen(cp);
 			goto next_option;
 		}
 		cp = "no-X11-forwarding";
 		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
 			auth_debug_add("X11 forwarding disabled.");
 			no_x11_forwarding_flag = 1;
 			opts += strlen(cp);
 			goto next_option;
 		}
 		cp = "no-pty";
 		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
 			auth_debug_add("Pty allocation disabled.");
 			no_pty_flag = 1;
 			opts += strlen(cp);
 			goto next_option;
 		}
 		cp = "no-user-rc";
 		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
 			auth_debug_add("User rc file execution disabled.");
 			no_user_rc = 1;
 			opts += strlen(cp);
 			goto next_option;
 		}
 		cp = "command=\"";
 		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
 			opts += strlen(cp);
 			if (forced_command != NULL)
 				free(forced_command);
 			forced_command = xmalloc(strlen(opts) + 1);
 			i = 0;
 			while (*opts) {
 				if (*opts == '"')
 					break;
 				if (*opts == '\\' && opts[1] == '"') {
 					opts += 2;
 					forced_command[i++] = '"';
 					continue;
 				}
 				forced_command[i++] = *opts++;
 			}
 			if (!*opts) {
 				debug("%.100s, line %lu: missing end quote",
 				    file, linenum);
 				auth_debug_add("%.100s, line %lu: missing end quote",
 				    file, linenum);
 				free(forced_command);
 				forced_command = NULL;
 				goto bad_option;
 			}
 			forced_command[i] = '\0';
 			auth_debug_add("Forced command.");
 			opts++;
 			goto next_option;
 		}
 		cp = "principals=\"";
 		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
 			opts += strlen(cp);
 			if (authorized_principals != NULL)
 				free(authorized_principals);
 			authorized_principals = xmalloc(strlen(opts) + 1);
 			i = 0;
 			while (*opts) {
 				if (*opts == '"')
 					break;
 				if (*opts == '\\' && opts[1] == '"') {
 					opts += 2;
 					authorized_principals[i++] = '"';
 					continue;
 				}
 				authorized_principals[i++] = *opts++;
 			}
 			if (!*opts) {
 				debug("%.100s, line %lu: missing end quote",
 				    file, linenum);
 				auth_debug_add("%.100s, line %lu: missing end quote",
 				    file, linenum);
 				free(authorized_principals);
 				authorized_principals = NULL;
 				goto bad_option;
 			}
 			authorized_principals[i] = '\0';
 			auth_debug_add("principals: %.900s",
 			    authorized_principals);
 			opts++;
 			goto next_option;
 		}
 		cp = "environment=\"";
 		if (options.permit_user_env &&
 		    strncasecmp(opts, cp, strlen(cp)) == 0) {
 			char *s;
 			struct envstring *new_envstring;

 			opts += strlen(cp);
 			s = xmalloc(strlen(opts) + 1);
 			i = 0;
 			while (*opts) {
 				if (*opts == '"')
 					break;
 				if (*opts == '\\' && opts[1] == '"') {
 					opts += 2;
 					s[i++] = '"';
 					continue;
 				}
 				s[i++] = *opts++;
 			}
 			if (!*opts) {
 				debug("%.100s, line %lu: missing end quote",
 				    file, linenum);
 				auth_debug_add("%.100s, line %lu: missing end quote",
 				    file, linenum);
 				free(s);
 				goto bad_option;
 			}
 			s[i] = '\0';
 			auth_debug_add("Adding to environment: %.900s", s);
 			debug("Adding to environment: %.900s", s);
 			opts++;
 			new_envstring = xmalloc(sizeof(struct envstring));
 			new_envstring->s = s;
 			new_envstring->next = custom_environment;
 			custom_environment = new_envstring;
 			goto next_option;
 		}
 		cp = "from=\"";
 		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
 			const char *remote_ip = get_remote_ipaddr();
 			const char *remote_host = get_canonical_hostname(
 			    options.use_dns);
 			char *patterns = xmalloc(strlen(opts) + 1);

 			opts += strlen(cp);
 			i = 0;
 			while (*opts) {
 				if (*opts == '"')
 					break;
 				if (*opts == '\\' && opts[1] == '"') {
 					opts += 2;
 					patterns[i++] = '"';
 					continue;
 				}
 				patterns[i++] = *opts++;
 			}
 			if (!*opts) {
 				debug("%.100s, line %lu: missing end quote",
 				    file, linenum);
 				auth_debug_add("%.100s, line %lu: missing end quote",
 				    file, linenum);
 				free(patterns);
 				goto bad_option;
 			}
 			patterns[i] = '\0';
 			opts++;
 			switch (match_host_and_ip(remote_host, remote_ip,
 			    patterns)) {
 			case 1:
 				free(patterns);
 				/* Host name matches. */
 				goto next_option;
 			case -1:
 				debug("%.100s, line %lu: invalid criteria",
 				    file, linenum);
 				auth_debug_add("%.100s, line %lu: "
 				    "invalid criteria", file, linenum);
 				/* FALLTHROUGH */
 			case 0:
 				free(patterns);
 				logit("Authentication tried for %.100s with "
 				    "correct key but not from a permitted "
 				    "host (host=%.200s, ip=%.200s).",
 				    pw->pw_name, remote_host, remote_ip);
 				auth_debug_add("Your host '%.200s' is not "
 				    "permitted to use this key for login.",
 				    remote_host);
 				break;
 			}
 			/* deny access */
 			return 0;
 		}
 		cp = "permitopen=\"";
 		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
 			char *host, *p;
 			int port;
 			char *patterns = xmalloc(strlen(opts) + 1);

 			opts += strlen(cp);
 			i = 0;
 			while (*opts) {
 				if (*opts == '"')
 					break;
 				if (*opts == '\\' && opts[1] == '"') {
 					opts += 2;
 					patterns[i++] = '"';
 					continue;
 				}
 				patterns[i++] = *opts++;
 			}
 			if (!*opts) {
 				debug("%.100s, line %lu: missing end quote",
 				    file, linenum);
 				auth_debug_add("%.100s, line %lu: missing "
 				    "end quote", file, linenum);
 				free(patterns);
 				goto bad_option;
 			}
 			patterns[i] = '\0';
 			opts++;
 			p = patterns;
 			host = hpdelim(&p);
 			if (host == NULL || strlen(host) >= NI_MAXHOST) {
 				debug("%.100s, line %lu: Bad permitopen "
 				    "specification <%.100s>", file, linenum,
 				    patterns);
 				auth_debug_add("%.100s, line %lu: "
 				    "Bad permitopen specification", file,
 				    linenum);
 				free(patterns);
 				goto bad_option;
 			}
 			host = cleanhostname(host);
 			if (p == NULL || (port = permitopen_port(p)) < 0) {
 				debug("%.100s, line %lu: Bad permitopen port "
 				    "<%.100s>", file, linenum, p ? p : "");
 				auth_debug_add("%.100s, line %lu: "
 				    "Bad permitopen port", file, linenum);
 				free(patterns);
 				goto bad_option;
 			}
 			if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0)
 				channel_add_permitted_opens(host, port);
 			free(patterns);
 			goto next_option;
 		}
 		cp = "tunnel=\"";
 		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
 			char *tun = NULL;
 			opts += strlen(cp);
 			tun = xmalloc(strlen(opts) + 1);
 			i = 0;
 			while (*opts) {
 				if (*opts == '"')
 					break;
 				tun[i++] = *opts++;
 			}
 			if (!*opts) {
 				debug("%.100s, line %lu: missing end quote",
 				    file, linenum);
 				auth_debug_add("%.100s, line %lu: missing end quote",
 				    file, linenum);
 				free(tun);
 				forced_tun_device = -1;
 				goto bad_option;
 			}
 			tun[i] = '\0';
 			forced_tun_device = a2tun(tun, NULL);
 			free(tun);
 			if (forced_tun_device == SSH_TUNID_ERR) {
 				debug("%.100s, line %lu: invalid tun device",
 				    file, linenum);
 				auth_debug_add("%.100s, line %lu: invalid tun device",
 				    file, linenum);
 				forced_tun_device = -1;
 				goto bad_option;
 			}
 			auth_debug_add("Forced tun device: %d", forced_tun_device);
 			opts++;
 			goto next_option;
 		}
 next_option:
 		/*
 		 * Skip the comma, and move to the next option
 		 * (or break out if there are no more).
 		 */
 		if (!*opts)
 			fatal("Bugs in auth-options.c option processing.");
 		if (*opts == ' ' || *opts == '\t')
 			break;		/* End of options. */
 		if (*opts != ',')
 			goto bad_option;
 		opts++;
 		/* Process the next option. */
 	}

 	/* grant access */
 	return 1;

 bad_option:
 	logit("Bad options in %.100s file, line %lu: %.50s",
 	    file, linenum, opts);
 	auth_debug_add("Bad options in %.100s file, line %lu: %.50s",
 	    file, linenum, opts);

 	/* deny access */
 	return 0;
 }

 #define OPTIONS_CRITICAL	1
 #define OPTIONS_EXTENSIONS	2
 static int
 parse_option_list(u_char *optblob, size_t optblob_len, struct passwd *pw,
     u_int which, int crit,
     int *cert_no_port_forwarding_flag,
     int *cert_no_agent_forwarding_flag,
     int *cert_no_x11_forwarding_flag,
     int *cert_no_pty_flag,
     int *cert_no_user_rc,
     char **cert_forced_command,
     int *cert_source_address_done)
 {
 	char *command, *allowed;
 	const char *remote_ip;
 	char *name = NULL;
 	u_char *data_blob = NULL;
 	u_int nlen, dlen, clen;
 	Buffer c, data;
 	int ret = -1, found;

 	buffer_init(&data);

 	/* Make copy to avoid altering original */
 	buffer_init(&c);
 	buffer_append(&c, optblob, optblob_len);

 	while (buffer_len(&c) > 0) {
 		if ((name = buffer_get_cstring_ret(&c, &nlen)) == NULL ||
 		    (data_blob = buffer_get_string_ret(&c, &dlen)) == NULL) {
 			error("Certificate options corrupt");
 			goto out;
 		}
 		buffer_append(&data, data_blob, dlen);
 		debug3("found certificate option \"%.100s\" len %u",
 		    name, dlen);
 		found = 0;
 		if ((which & OPTIONS_EXTENSIONS) != 0) {
 			if (strcmp(name, "permit-X11-forwarding") == 0) {
 				*cert_no_x11_forwarding_flag = 0;
 				found = 1;
 			} else if (strcmp(name,
 			    "permit-agent-forwarding") == 0) {
 				*cert_no_agent_forwarding_flag = 0;
 				found = 1;
 			} else if (strcmp(name,
 			    "permit-port-forwarding") == 0) {
 				*cert_no_port_forwarding_flag = 0;
 				found = 1;
 			} else if (strcmp(name, "permit-pty") == 0) {
 				*cert_no_pty_flag = 0;
 				found = 1;
 			} else if (strcmp(name, "permit-user-rc") == 0) {
 				*cert_no_user_rc = 0;
 				found = 1;
 			}
 		}
 		if (!found && (which & OPTIONS_CRITICAL) != 0) {
 			if (strcmp(name, "force-command") == 0) {
 				if ((command = buffer_get_cstring_ret(&data,
 				    &clen)) == NULL) {
 					error("Certificate constraint \"%s\" "
 					    "corrupt", name);
 					goto out;
 				}
 				if (*cert_forced_command != NULL) {
 					error("Certificate has multiple "
 					    "force-command options");
 					free(command);
 					goto out;
 				}
 				*cert_forced_command = command;
 				found = 1;
 			}
 			if (strcmp(name, "source-address") == 0) {
 				if ((allowed = buffer_get_cstring_ret(&data,
 				    &clen)) == NULL) {
 					error("Certificate constraint "
 					    "\"%s\" corrupt", name);
 					goto out;
 				}
 				if ((*cert_source_address_done)++) {
 					error("Certificate has multiple "
 					    "source-address options");
 					free(allowed);
 					goto out;
 				}
 				remote_ip = get_remote_ipaddr();
 				switch (addr_match_cidr_list(remote_ip,
 				    allowed)) {
 				case 1:
 					/* accepted */
 					free(allowed);
 					break;
 				case 0:
 					/* no match */
 					logit("Authentication tried for %.100s "
 					    "with valid certificate but not "
 					    "from a permitted host "
 					    "(ip=%.200s).", pw->pw_name,
 					    remote_ip);
 					auth_debug_add("Your address '%.200s' "
 					    "is not permitted to use this "
 					    "certificate for login.",
 					    remote_ip);
 					free(allowed);
 					goto out;
 				case -1:
 					error("Certificate source-address "
 					    "contents invalid");
 					free(allowed);
 					goto out;
 				}
 				found = 1;
 			}
 		}

 		if (!found) {
 			if (crit) {
 				error("Certificate critical option \"%s\" "
 				    "is not supported", name);
 				goto out;
 			} else {
 				logit("Certificate extension \"%s\" "
 				    "is not supported", name);
 			}
 		} else if (buffer_len(&data) != 0) {
 			error("Certificate option \"%s\" corrupt "
 			    "(extra data)", name);
 			goto out;
 		}
 		buffer_clear(&data);
 		free(name);
 		free(data_blob);
 		name = NULL;
 		data_blob = NULL;
 	}
 	/* successfully parsed all options */
 	ret = 0;

  out:
 	if (ret != 0 &&
 	    cert_forced_command != NULL &&
 	    *cert_forced_command != NULL) {
 		free(*cert_forced_command);
 		*cert_forced_command = NULL;
 	}
 	if (name != NULL)
 		free(name);
 	if (data_blob != NULL)
 		free(data_blob);
 	buffer_free(&data);
 	buffer_free(&c);
 	return ret;
 }

 /*
  * Set options from critical certificate options. These supersede user key
  * options so this must be called after auth_parse_options().
  */
 int
 auth_cert_options(Key *k, struct passwd *pw)
 {
 	int cert_no_port_forwarding_flag = 1;
 	int cert_no_agent_forwarding_flag = 1;
 	int cert_no_x11_forwarding_flag = 1;
 	int cert_no_pty_flag = 1;
 	int cert_no_user_rc = 1;
 	char *cert_forced_command = NULL;
 	int cert_source_address_done = 0;

 	if (key_cert_is_legacy(k)) {
 		/* All options are in the one field for v00 certs */
 		if (parse_option_list(buffer_ptr(&k->cert->critical),
 		    buffer_len(&k->cert->critical), pw,
 		    OPTIONS_CRITICAL|OPTIONS_EXTENSIONS, 1,
 		    &cert_no_port_forwarding_flag,
 		    &cert_no_agent_forwarding_flag,
 		    &cert_no_x11_forwarding_flag,
 		    &cert_no_pty_flag,
 		    &cert_no_user_rc,
 		    &cert_forced_command,
 		    &cert_source_address_done) == -1)
 			return -1;
 	} else {
 		/* Separate options and extensions for v01 certs */
 		if (parse_option_list(buffer_ptr(&k->cert->critical),
 		    buffer_len(&k->cert->critical), pw,
 		    OPTIONS_CRITICAL, 1, NULL, NULL, NULL, NULL, NULL,
 		    &cert_forced_command,
 		    &cert_source_address_done) == -1)
 			return -1;
 		if (parse_option_list(buffer_ptr(&k->cert->extensions),
 		    buffer_len(&k->cert->extensions), pw,
 		    OPTIONS_EXTENSIONS, 1,
 		    &cert_no_port_forwarding_flag,
 		    &cert_no_agent_forwarding_flag,
 		    &cert_no_x11_forwarding_flag,
 		    &cert_no_pty_flag,
 		    &cert_no_user_rc,
 		    NULL, NULL) == -1)
 			return -1;
 	}

 	no_port_forwarding_flag |= cert_no_port_forwarding_flag;
 	no_agent_forwarding_flag |= cert_no_agent_forwarding_flag;
 	no_x11_forwarding_flag |= cert_no_x11_forwarding_flag;
 	no_pty_flag |= cert_no_pty_flag;
 	no_user_rc |= cert_no_user_rc;
 	/* CA-specified forced command supersedes key option */
 	if (cert_forced_command != NULL) {
 		if (forced_command != NULL)
 			free(forced_command);
 		forced_command = cert_forced_command;
 	}
 	return 0;
 }
	/* $OpenBSD: auth-options.c,v 1.59 2013/07/12 00:19:58 djm Exp $ */
	/*
	* Author: Tatu Ylonen <ylo@cs.hut.fi>
	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
	* All rights reserved
	* 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 <netdb.h>
	#include <pwd.h>
	#include <string.h>
	#include <stdio.h>
	#include <stdarg.h>

	#include "openbsd-compat/sys-queue.h"
	#include "xmalloc.h"
	#include "match.h"
	#include "log.h"
	#include "canohost.h"
	#include "buffer.h"
	#include "channels.h"
	#include "servconf.h"
	#include "misc.h"
	#include "key.h"
	#include "auth-options.h"
	#include "hostfile.h"
	#include "auth.h"
	#ifdef GSSAPI
	#include "ssh-gss.h"
	#endif
	#include "monitor_wrap.h"

	/* Flags set authorized_keys flags */
	int no_port_forwarding_flag = 0;
	int no_agent_forwarding_flag = 0;
	int no_x11_forwarding_flag = 0;
	int no_pty_flag = 0;
	int no_user_rc = 0;
	int key_is_cert_authority = 0;

	/* "command=" option. */
	char *forced_command = NULL;

	/* "environment=" options. */
	struct envstring *custom_environment = NULL;

	/* "tunnel=" option. */
	int forced_tun_device = -1;

	/* "principals=" option. */
	char *authorized_principals = NULL;

	extern ServerOptions options;

	void
	auth_clear_options(void)
	{
	no_agent_forwarding_flag = 0;
	no_port_forwarding_flag = 0;
	no_pty_flag = 0;
	no_x11_forwarding_flag = 0;
	no_user_rc = 0;
	key_is_cert_authority = 0;
	while (custom_environment) {
	struct envstring *ce = custom_environment;
	custom_environment = ce->next;
	free(ce->s);
	free(ce);
	}
	if (forced_command) {
	free(forced_command);
	forced_command = NULL;
	}
	if (authorized_principals) {
	free(authorized_principals);
	authorized_principals = NULL;
	}
	forced_tun_device = -1;
	channel_clear_permitted_opens();
	}

	/*
	* return 1 if access is granted, 0 if not.
	* side effect: sets key option flags
	*/
	int
	auth_parse_options(struct passwd pw, char opts, char *file, u_long linenum)
	{
	const char *cp;
	int i;

	/* reset options */
	auth_clear_options();

	if (!opts)
	return 1;

	while (opts && opts != ' ' && *opts != '\t') {
	cp = "cert-authority";
	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
	key_is_cert_authority = 1;
	opts += strlen(cp);
	goto next_option;
	}
	cp = "no-port-forwarding";
	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
	auth_debug_add("Port forwarding disabled.");
	no_port_forwarding_flag = 1;
	opts += strlen(cp);
	goto next_option;
	}
	cp = "no-agent-forwarding";
	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
	auth_debug_add("Agent forwarding disabled.");
	no_agent_forwarding_flag = 1;
	opts += strlen(cp);
	goto next_option;
	}
	cp = "no-X11-forwarding";
	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
	auth_debug_add("X11 forwarding disabled.");
	no_x11_forwarding_flag = 1;
	opts += strlen(cp);
	goto next_option;
	}
	cp = "no-pty";
	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
	auth_debug_add("Pty allocation disabled.");
	no_pty_flag = 1;
	opts += strlen(cp);
	goto next_option;
	}
	cp = "no-user-rc";
	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
	auth_debug_add("User rc file execution disabled.");
	no_user_rc = 1;
	opts += strlen(cp);
	goto next_option;
	}
	cp = "command=\"";
	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
	opts += strlen(cp);
	if (forced_command != NULL)
	free(forced_command);
	forced_command = xmalloc(strlen(opts) + 1);
	i = 0;
	while (*opts) {
	if (*opts == '"')
	break;
	if (*opts == '\\' && opts[1] == '"') {
	opts += 2;
	forced_command[i++] = '"';
	continue;
	}
	forced_command[i++] = *opts++;
	}
	if (!*opts) {
	debug("%.100s, line %lu: missing end quote",
	file, linenum);
	auth_debug_add("%.100s, line %lu: missing end quote",
	file, linenum);
	free(forced_command);
	forced_command = NULL;
	goto bad_option;
	}
	forced_command[i] = '\0';
	auth_debug_add("Forced command.");
	opts++;
	goto next_option;
	}
	cp = "principals=\"";
	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
	opts += strlen(cp);
	if (authorized_principals != NULL)
	free(authorized_principals);
	authorized_principals = xmalloc(strlen(opts) + 1);
	i = 0;
	while (*opts) {
	if (*opts == '"')
	break;
	if (*opts == '\\' && opts[1] == '"') {
	opts += 2;
	authorized_principals[i++] = '"';
	continue;
	}
	authorized_principals[i++] = *opts++;
	}
	if (!*opts) {
	debug("%.100s, line %lu: missing end quote",
	file, linenum);
	auth_debug_add("%.100s, line %lu: missing end quote",
	file, linenum);
	free(authorized_principals);
	authorized_principals = NULL;
	goto bad_option;
	}
	authorized_principals[i] = '\0';
	auth_debug_add("principals: %.900s",
	authorized_principals);
	opts++;
	goto next_option;
	}
	cp = "environment=\"";
	if (options.permit_user_env &&
	strncasecmp(opts, cp, strlen(cp)) == 0) {
	char *s;
	struct envstring *new_envstring;

	opts += strlen(cp);
	s = xmalloc(strlen(opts) + 1);
	i = 0;
	while (*opts) {
	if (*opts == '"')
	break;
	if (*opts == '\\' && opts[1] == '"') {
	opts += 2;
	s[i++] = '"';
	continue;
	}
	s[i++] = *opts++;
	}
	if (!*opts) {
	debug("%.100s, line %lu: missing end quote",
	file, linenum);
	auth_debug_add("%.100s, line %lu: missing end quote",
	file, linenum);
	free(s);
	goto bad_option;
	}
	s[i] = '\0';
	auth_debug_add("Adding to environment: %.900s", s);
	debug("Adding to environment: %.900s", s);
	opts++;
	new_envstring = xmalloc(sizeof(struct envstring));
	new_envstring->s = s;
	new_envstring->next = custom_environment;
	custom_environment = new_envstring;
	goto next_option;
	}
	cp = "from=\"";
	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
	const char *remote_ip = get_remote_ipaddr();
	const char *remote_host = get_canonical_hostname(
	options.use_dns);
	char *patterns = xmalloc(strlen(opts) + 1);

	opts += strlen(cp);
	i = 0;
	while (*opts) {
	if (*opts == '"')
	break;
	if (*opts == '\\' && opts[1] == '"') {
	opts += 2;
	patterns[i++] = '"';
	continue;
	}
	patterns[i++] = *opts++;
	}
	if (!*opts) {
	debug("%.100s, line %lu: missing end quote",
	file, linenum);
	auth_debug_add("%.100s, line %lu: missing end quote",
	file, linenum);
	free(patterns);
	goto bad_option;
	}
	patterns[i] = '\0';
	opts++;
	switch (match_host_and_ip(remote_host, remote_ip,
	patterns)) {
	case 1:
	free(patterns);
	/* Host name matches. */
	goto next_option;
	case -1:
	debug("%.100s, line %lu: invalid criteria",
	file, linenum);
	auth_debug_add("%.100s, line %lu: "
	"invalid criteria", file, linenum);
	/* FALLTHROUGH */
	case 0:
	free(patterns);
	logit("Authentication tried for %.100s with "
	"correct key but not from a permitted "
	"host (host=%.200s, ip=%.200s).",
	pw->pw_name, remote_host, remote_ip);
	auth_debug_add("Your host '%.200s' is not "
	"permitted to use this key for login.",
	remote_host);
	break;
	}
	/* deny access */
	return 0;
	}
	cp = "permitopen=\"";
	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
	char host, p;
	int port;
	char *patterns = xmalloc(strlen(opts) + 1);

	opts += strlen(cp);
	i = 0;
	while (*opts) {
	if (*opts == '"')
	break;
	if (*opts == '\\' && opts[1] == '"') {
	opts += 2;
	patterns[i++] = '"';
	continue;
	}
	patterns[i++] = *opts++;
	}
	if (!*opts) {
	debug("%.100s, line %lu: missing end quote",
	file, linenum);
	auth_debug_add("%.100s, line %lu: missing "
	"end quote", file, linenum);
	free(patterns);
	goto bad_option;
	}
	patterns[i] = '\0';
	opts++;
	p = patterns;
	host = hpdelim(&p);
	if (host == NULL \|\| strlen(host) >= NI_MAXHOST) {
	debug("%.100s, line %lu: Bad permitopen "
	"specification <%.100s>", file, linenum,
	patterns);
	auth_debug_add("%.100s, line %lu: "
	"Bad permitopen specification", file,
	linenum);
	free(patterns);
	goto bad_option;
	}
	host = cleanhostname(host);
	if (p == NULL \|\| (port = permitopen_port(p)) < 0) {
	debug("%.100s, line %lu: Bad permitopen port "
	"<%.100s>", file, linenum, p ? p : "");
	auth_debug_add("%.100s, line %lu: "
	"Bad permitopen port", file, linenum);
	free(patterns);
	goto bad_option;
	}
	if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0)
	channel_add_permitted_opens(host, port);
	free(patterns);
	goto next_option;
	}
	cp = "tunnel=\"";
	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
	char *tun = NULL;
	opts += strlen(cp);
	tun = xmalloc(strlen(opts) + 1);
	i = 0;
	while (*opts) {
	if (*opts == '"')
	break;
	tun[i++] = *opts++;
	}
	if (!*opts) {
	debug("%.100s, line %lu: missing end quote",
	file, linenum);
	auth_debug_add("%.100s, line %lu: missing end quote",
	file, linenum);
	free(tun);
	forced_tun_device = -1;
	goto bad_option;
	}
	tun[i] = '\0';
	forced_tun_device = a2tun(tun, NULL);
	free(tun);
	if (forced_tun_device == SSH_TUNID_ERR) {
	debug("%.100s, line %lu: invalid tun device",
	file, linenum);
	auth_debug_add("%.100s, line %lu: invalid tun device",
	file, linenum);
	forced_tun_device = -1;
	goto bad_option;
	}
	auth_debug_add("Forced tun device: %d", forced_tun_device);
	opts++;
	goto next_option;
	}
	next_option:
	/*
	* Skip the comma, and move to the next option
	* (or break out if there are no more).
	*/
	if (!*opts)
	fatal("Bugs in auth-options.c option processing.");
	if (opts == ' ' \|\| opts == '\t')
	break; /* End of options. */
	if (*opts != ',')
	goto bad_option;
	opts++;
	/* Process the next option. */
	}

	/* grant access */
	return 1;

	bad_option:
	logit("Bad options in %.100s file, line %lu: %.50s",
	file, linenum, opts);
	auth_debug_add("Bad options in %.100s file, line %lu: %.50s",
	file, linenum, opts);

	/* deny access */
	return 0;
	}

	#define OPTIONS_CRITICAL 1
	#define OPTIONS_EXTENSIONS 2
	static int
	parse_option_list(u_char optblob, size_t optblob_len, struct passwd pw,
	u_int which, int crit,
	int *cert_no_port_forwarding_flag,
	int *cert_no_agent_forwarding_flag,
	int *cert_no_x11_forwarding_flag,
	int *cert_no_pty_flag,
	int *cert_no_user_rc,
	char **cert_forced_command,
	int *cert_source_address_done)
	{
	char command, allowed;
	const char *remote_ip;
	char *name = NULL;
	u_char *data_blob = NULL;
	u_int nlen, dlen, clen;
	Buffer c, data;
	int ret = -1, found;

	buffer_init(&data);

	/* Make copy to avoid altering original */
	buffer_init(&c);
	buffer_append(&c, optblob, optblob_len);

	while (buffer_len(&c) > 0) {
	if ((name = buffer_get_cstring_ret(&c, &nlen)) == NULL \|\|
	(data_blob = buffer_get_string_ret(&c, &dlen)) == NULL) {
	error("Certificate options corrupt");
	goto out;
	}
	buffer_append(&data, data_blob, dlen);
	debug3("found certificate option \"%.100s\" len %u",
	name, dlen);
	found = 0;
	if ((which & OPTIONS_EXTENSIONS) != 0) {
	if (strcmp(name, "permit-X11-forwarding") == 0) {
	*cert_no_x11_forwarding_flag = 0;
	found = 1;
	} else if (strcmp(name,
	"permit-agent-forwarding") == 0) {
	*cert_no_agent_forwarding_flag = 0;
	found = 1;
	} else if (strcmp(name,
	"permit-port-forwarding") == 0) {
	*cert_no_port_forwarding_flag = 0;
	found = 1;
	} else if (strcmp(name, "permit-pty") == 0) {
	*cert_no_pty_flag = 0;
	found = 1;
	} else if (strcmp(name, "permit-user-rc") == 0) {
	*cert_no_user_rc = 0;
	found = 1;
	}
	}
	if (!found && (which & OPTIONS_CRITICAL) != 0) {
	if (strcmp(name, "force-command") == 0) {
	if ((command = buffer_get_cstring_ret(&data,
	&clen)) == NULL) {
	error("Certificate constraint \"%s\" "
	"corrupt", name);
	goto out;
	}
	if (*cert_forced_command != NULL) {
	error("Certificate has multiple "
	"force-command options");
	free(command);
	goto out;
	}
	*cert_forced_command = command;
	found = 1;
	}
	if (strcmp(name, "source-address") == 0) {
	if ((allowed = buffer_get_cstring_ret(&data,
	&clen)) == NULL) {
	error("Certificate constraint "
	"\"%s\" corrupt", name);
	goto out;
	}
	if ((*cert_source_address_done)++) {
	error("Certificate has multiple "
	"source-address options");
	free(allowed);
	goto out;
	}
	remote_ip = get_remote_ipaddr();
	switch (addr_match_cidr_list(remote_ip,
	allowed)) {
	case 1:
	/* accepted */
	free(allowed);
	break;
	case 0:
	/* no match */
	logit("Authentication tried for %.100s "
	"with valid certificate but not "
	"from a permitted host "
	"(ip=%.200s).", pw->pw_name,
	remote_ip);
	auth_debug_add("Your address '%.200s' "
	"is not permitted to use this "
	"certificate for login.",
	remote_ip);
	free(allowed);
	goto out;
	case -1:
	error("Certificate source-address "
	"contents invalid");
	free(allowed);
	goto out;
	}
	found = 1;
	}
	}

	if (!found) {
	if (crit) {
	error("Certificate critical option \"%s\" "
	"is not supported", name);
	goto out;
	} else {
	logit("Certificate extension \"%s\" "
	"is not supported", name);
	}
	} else if (buffer_len(&data) != 0) {
	error("Certificate option \"%s\" corrupt "
	"(extra data)", name);
	goto out;
	}
	buffer_clear(&data);
	free(name);
	free(data_blob);
	name = NULL;
	data_blob = NULL;
	}
	/* successfully parsed all options */
	ret = 0;

	out:
	if (ret != 0 &&
	cert_forced_command != NULL &&
	*cert_forced_command != NULL) {
	free(*cert_forced_command);
	*cert_forced_command = NULL;
	}
	if (name != NULL)
	free(name);
	if (data_blob != NULL)
	free(data_blob);
	buffer_free(&data);
	buffer_free(&c);
	return ret;
	}

	/*
	* Set options from critical certificate options. These supersede user key
	* options so this must be called after auth_parse_options().
	*/
	int
	auth_cert_options(Key k, struct passwd pw)
	{
	int cert_no_port_forwarding_flag = 1;
	int cert_no_agent_forwarding_flag = 1;
	int cert_no_x11_forwarding_flag = 1;
	int cert_no_pty_flag = 1;
	int cert_no_user_rc = 1;
	char *cert_forced_command = NULL;
	int cert_source_address_done = 0;

	if (key_cert_is_legacy(k)) {
	/* All options are in the one field for v00 certs */
	if (parse_option_list(buffer_ptr(&k->cert->critical),
	buffer_len(&k->cert->critical), pw,
	OPTIONS_CRITICAL\|OPTIONS_EXTENSIONS, 1,
	&cert_no_port_forwarding_flag,
	&cert_no_agent_forwarding_flag,
	&cert_no_x11_forwarding_flag,
	&cert_no_pty_flag,
	&cert_no_user_rc,
	&cert_forced_command,
	&cert_source_address_done) == -1)
	return -1;
	} else {
	/* Separate options and extensions for v01 certs */
	if (parse_option_list(buffer_ptr(&k->cert->critical),
	buffer_len(&k->cert->critical), pw,
	OPTIONS_CRITICAL, 1, NULL, NULL, NULL, NULL, NULL,
	&cert_forced_command,
	&cert_source_address_done) == -1)
	return -1;
	if (parse_option_list(buffer_ptr(&k->cert->extensions),
	buffer_len(&k->cert->extensions), pw,
	OPTIONS_EXTENSIONS, 1,
	&cert_no_port_forwarding_flag,
	&cert_no_agent_forwarding_flag,
	&cert_no_x11_forwarding_flag,
	&cert_no_pty_flag,
	&cert_no_user_rc,
	NULL, NULL) == -1)
	return -1;
	}

	no_port_forwarding_flag \|= cert_no_port_forwarding_flag;
	no_agent_forwarding_flag \|= cert_no_agent_forwarding_flag;
	no_x11_forwarding_flag \|= cert_no_x11_forwarding_flag;
	no_pty_flag \|= cert_no_pty_flag;
	no_user_rc \|= cert_no_user_rc;
	/* CA-specified forced command supersedes key option */
	if (cert_forced_command != NULL) {
	if (forced_command != NULL)
	free(forced_command);
	forced_command = cert_forced_command;
	}
	return 0;
	}