[gssapi-openssh.git] / openssh / auth.c

/* $OpenBSD: auth.c,v 1.75 2006/08/03 03:34:41 deraadt Exp $ */
/*
 * Copyright (c) 2000 Markus Friedl.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "includes.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>

#include <netinet/in.h>

#include <errno.h>
#ifdef HAVE_PATHS_H
# include <paths.h>
#endif
#include <pwd.h>
#ifdef HAVE_LOGIN_H
#include <login.h>
#endif
#ifdef USE_SHADOW
#include <shadow.h>
#endif
#ifdef HAVE_LIBGEN_H
#include <libgen.h>
#endif
#include <stdarg.h>
#include <stdio.h>
#include <string.h>

#include "xmalloc.h"
#include "match.h"
#include "groupaccess.h"
#include "log.h"
#include "buffer.h"
#include "servconf.h"
#include "key.h"
#include "hostfile.h"
#include "auth.h"
#include "auth-options.h"
#include "canohost.h"
#include "uidswap.h"
#include "misc.h"
#include "packet.h"
#include "loginrec.h"
#ifdef GSSAPI
#include "ssh-gss.h"
#endif
#include "monitor_wrap.h"

/* import */
extern ServerOptions options;
extern int use_privsep;
extern Buffer loginmsg;
extern struct passwd *privsep_pw;

/* Debugging messages */
Buffer auth_debug;
int auth_debug_init;

/*
 * Check if the user is allowed to log in via ssh. If user is listed
 * in DenyUsers or one of user's groups is listed in DenyGroups, false
 * will be returned. If AllowUsers isn't empty and user isn't listed
 * there, or if AllowGroups isn't empty and one of user's groups isn't
 * listed there, false will be returned.
 * If the user's shell is not executable, false will be returned.
 * Otherwise true is returned.
 */
int
allowed_user(struct passwd * pw)
{
	struct stat st;
	const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
	char *shell;
	u_int i;
#ifdef USE_SHADOW
	struct spwd *spw = NULL;
#endif

	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
	if (!pw || !pw->pw_name)
		return 0;

#ifdef USE_SHADOW
	if (!options.use_pam)
		spw = getspnam(pw->pw_name);
#ifdef HAS_SHADOW_EXPIRE
	if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
		return 0;
#endif /* HAS_SHADOW_EXPIRE */
#endif /* USE_SHADOW */

	/* grab passwd field for locked account check */
#ifdef USE_SHADOW
	if (spw != NULL)
#if defined(HAVE_LIBIAF)  &&  !defined(BROKEN_LIBIAF)
		passwd = get_iaf_password(pw);
#else
		passwd = spw->sp_pwdp;
#endif /* HAVE_LIBIAF  && !BROKEN_LIBIAF */
#else
	passwd = pw->pw_passwd;
#endif

	/* check for locked account */
	if (!options.use_pam && passwd && *passwd) {
		int locked = 0;

#ifdef LOCKED_PASSWD_STRING
		if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
			 locked = 1;
#endif
#ifdef LOCKED_PASSWD_PREFIX
		if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
		    strlen(LOCKED_PASSWD_PREFIX)) == 0)
			 locked = 1;
#endif
#ifdef LOCKED_PASSWD_SUBSTR
		if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
			locked = 1;
#endif
#if defined(HAVE_LIBIAF)  &&  !defined(BROKEN_LIBIAF)
		free(passwd);
#endif /* HAVE_LIBIAF  && !BROKEN_LIBIAF */
		if (locked) {
			logit("User %.100s not allowed because account is locked",
			    pw->pw_name);
			return 0;
		}
	}

	/*
	 * Get the shell from the password data.  An empty shell field is
	 * legal, and means /bin/sh.
	 */
	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;

	/* deny if shell does not exists or is not executable */
	if (stat(shell, &st) != 0) {
		logit("User %.100s not allowed because shell %.100s does not exist",
		    pw->pw_name, shell);
		return 0;
	}
	if (S_ISREG(st.st_mode) == 0 ||
	    (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
		logit("User %.100s not allowed because shell %.100s is not executable",
		    pw->pw_name, shell);
		return 0;
	}

	if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
	    options.num_deny_groups > 0 || options.num_allow_groups > 0) {
		hostname = get_canonical_hostname(options.use_dns);
		ipaddr = get_remote_ipaddr();
	}

	/* Return false if user is listed in DenyUsers */
	if (options.num_deny_users > 0) {
		for (i = 0; i < options.num_deny_users; i++)
			if (match_user(pw->pw_name, hostname, ipaddr,
			    options.deny_users[i])) {
				logit("User %.100s from %.100s not allowed "
				    "because listed in DenyUsers",
				    pw->pw_name, hostname);
				return 0;
			}
	}
	/* Return false if AllowUsers isn't empty and user isn't listed there */
	if (options.num_allow_users > 0) {
		for (i = 0; i < options.num_allow_users; i++)
			if (match_user(pw->pw_name, hostname, ipaddr,
			    options.allow_users[i]))
				break;
		/* i < options.num_allow_users iff we break for loop */
		if (i >= options.num_allow_users) {
			logit("User %.100s from %.100s not allowed because "
			    "not listed in AllowUsers", pw->pw_name, hostname);
			return 0;
		}
	}
	if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
		/* Get the user's group access list (primary and supplementary) */
		if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
			logit("User %.100s from %.100s not allowed because "
			    "not in any group", pw->pw_name, hostname);
			return 0;
		}

		/* Return false if one of user's groups is listed in DenyGroups */
		if (options.num_deny_groups > 0)
			if (ga_match(options.deny_groups,
			    options.num_deny_groups)) {
				ga_free();
				logit("User %.100s from %.100s not allowed "
				    "because a group is listed in DenyGroups",
				    pw->pw_name, hostname);
				return 0;
			}
		/*
		 * Return false if AllowGroups isn't empty and one of user's groups
		 * isn't listed there
		 */
		if (options.num_allow_groups > 0)
			if (!ga_match(options.allow_groups,
			    options.num_allow_groups)) {
				ga_free();
				logit("User %.100s from %.100s not allowed "
				    "because none of user's groups are listed "
				    "in AllowGroups", pw->pw_name, hostname);
				return 0;
			}
		ga_free();
	}

#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
	if (!sys_auth_allowed_user(pw, &loginmsg))
		return 0;
#endif

	/* We found no reason not to let this user try to log on... */
	return 1;
}

void
auth_log(Authctxt *authctxt, int authenticated, char *method, char *info)
{
	void (*authlog) (const char *fmt,...) = verbose;
	char *authmsg;

	if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
		return;

	/* Raise logging level */
	if (authenticated == 1 ||
	    !authctxt->valid ||
	    authctxt->failures >= options.max_authtries / 2 ||
	    strcmp(method, "password") == 0)
		authlog = logit;

	if (authctxt->postponed)
		authmsg = "Postponed";
	else
		authmsg = authenticated ? "Accepted" : "Failed";

	authlog("%s %s for %s%.100s from %.200s port %d%s",
	    authmsg,
	    method,
	    authctxt->valid ? "" : "invalid user ",
	    (authctxt->user && authctxt->user[0]) ?
		authctxt->user : "unknown",
	    get_remote_ipaddr(),
	    get_remote_port(),
	    info);

#ifdef CUSTOM_FAILED_LOGIN
	if (authenticated == 0 && !authctxt->postponed &&
	    (strcmp(method, "password") == 0 ||
	    strncmp(method, "keyboard-interactive", 20) == 0 ||
	    strcmp(method, "challenge-response") == 0))
		record_failed_login(authctxt->user,
		    get_canonical_hostname(options.use_dns), "ssh");
# ifdef WITH_AIXAUTHENTICATE
	if (authenticated)
		sys_auth_record_login(authctxt->user,
		    get_canonical_hostname(options.use_dns), "ssh", &loginmsg);
# endif
#endif
#ifdef SSH_AUDIT_EVENTS
	if (authenticated == 0 && !authctxt->postponed)
		audit_event(audit_classify_auth(method));
#endif
}

/*
 * Check whether root logins are disallowed.
 */
int
auth_root_allowed(char *method)
{
	switch (options.permit_root_login) {
	case PERMIT_YES:
		return 1;
	case PERMIT_NO_PASSWD:
		if (strcmp(method, "password") != 0)
			return 1;
		break;
	case PERMIT_FORCED_ONLY:
		if (forced_command) {
			logit("Root login accepted for forced command.");
			return 1;
		}
		break;
	}
	logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
	return 0;
}


/*
 * Given a template and a passwd structure, build a filename
 * by substituting % tokenised options. Currently, %% becomes '%',
 * %h becomes the home directory and %u the username.
 *
 * This returns a buffer allocated by xmalloc.
 */
char *
expand_authorized_keys(const char *filename, struct passwd *pw)
{
	char *file, ret[MAXPATHLEN];
	int i;

	file = percent_expand(filename, "h", pw->pw_dir,
	    "u", pw->pw_name, (char *)NULL);

	/*
	 * Ensure that filename starts anchored. If not, be backward
	 * compatible and prepend the '%h/'
	 */
	if (*file == '/')
		return (file);

	i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
	if (i < 0 || (size_t)i >= sizeof(ret))
		fatal("expand_authorized_keys: path too long");
	xfree(file);
	return (xstrdup(ret));
}

char *
authorized_keys_file(struct passwd *pw)
{
	return expand_authorized_keys(options.authorized_keys_file, pw);
}

char *
authorized_keys_file2(struct passwd *pw)
{
	return expand_authorized_keys(options.authorized_keys_file2, pw);
}

/* return ok if key exists in sysfile or userfile */
HostStatus
check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
    const char *sysfile, const char *userfile)
{
	Key *found;
	char *user_hostfile;
	struct stat st;
	HostStatus host_status;

	/* Check if we know the host and its host key. */
	found = key_new(key->type);
	host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);

	if (host_status != HOST_OK && userfile != NULL) {
		user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
		if (options.strict_modes &&
		    (stat(user_hostfile, &st) == 0) &&
		    ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
		    (st.st_mode & 022) != 0)) {
			logit("Authentication refused for %.100s: "
			    "bad owner or modes for %.200s",
			    pw->pw_name, user_hostfile);
		} else {
			temporarily_use_uid(pw);
			host_status = check_host_in_hostfile(user_hostfile,
			    host, key, found, NULL);
			restore_uid();
		}
		xfree(user_hostfile);
	}
	key_free(found);

	debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
	    "ok" : "not found", host);
	return host_status;
}


/*
 * Check a given file for security. This is defined as all components
 * of the path to the file must be owned by either the owner of
 * of the file or root and no directories must be group or world writable.
 *
 * XXX Should any specific check be done for sym links ?
 *
 * Takes an open file descriptor, the file name, a uid and and
 * error buffer plus max size as arguments.
 *
 * Returns 0 on success and -1 on failure
 */
int
secure_filename(FILE *f, const char *file, struct passwd *pw,
    char *err, size_t errlen)
{
	uid_t uid = pw->pw_uid;
	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
	char *cp;
	int comparehome = 0;
	struct stat st;

	if (realpath(file, buf) == NULL) {
		snprintf(err, errlen, "realpath %s failed: %s", file,
		    strerror(errno));
		return -1;
	}
	if (realpath(pw->pw_dir, homedir) != NULL)
		comparehome = 1;

	/* check the open file to avoid races */
	if (fstat(fileno(f), &st) < 0 ||
	    (st.st_uid != 0 && st.st_uid != uid) ||
	    (st.st_mode & 022) != 0) {
		snprintf(err, errlen, "bad ownership or modes for file %s",
		    buf);
		return -1;
	}

	/* for each component of the canonical path, walking upwards */
	for (;;) {
		if ((cp = dirname(buf)) == NULL) {
			snprintf(err, errlen, "dirname() failed");
			return -1;
		}
		strlcpy(buf, cp, sizeof(buf));

		debug3("secure_filename: checking '%s'", buf);
		if (stat(buf, &st) < 0 ||
		    (st.st_uid != 0 && st.st_uid != uid) ||
		    (st.st_mode & 022) != 0) {
			snprintf(err, errlen,
			    "bad ownership or modes for directory %s", buf);
			return -1;
		}

		/* If are passed the homedir then we can stop */
		if (comparehome && strcmp(homedir, buf) == 0) {
			debug3("secure_filename: terminating check at '%s'",
			    buf);
			break;
		}
		/*
		 * dirname should always complete with a "/" path,
		 * but we can be paranoid and check for "." too
		 */
		if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
			break;
	}
	return 0;
}

struct passwd *
getpwnamallow(const char *user)
{
#ifdef HAVE_LOGIN_CAP
	extern login_cap_t *lc;
#ifdef BSD_AUTH
	auth_session_t *as;
#endif
#endif
	struct passwd *pw;

	parse_server_match_config(&options, user,
	    get_canonical_hostname(options.use_dns), get_remote_ipaddr());

	pw = getpwnam(user);
	if (pw == NULL) {
		logit("Invalid user %.100s from %.100s",
		      (user && user[0]) ? user : "unknown",
		      get_remote_ipaddr());
#ifdef CUSTOM_FAILED_LOGIN
		record_failed_login(user,
		    get_canonical_hostname(options.use_dns), "ssh");
#endif
#ifdef SSH_AUDIT_EVENTS
		audit_event(SSH_INVALID_USER);
#endif /* SSH_AUDIT_EVENTS */
		return (NULL);
	}
	if (!allowed_user(pw))
		return (NULL);
#ifdef HAVE_LOGIN_CAP
	if ((lc = login_getclass(pw->pw_class)) == NULL) {
		debug("unable to get login class: %s", user);
		return (NULL);
	}
#ifdef BSD_AUTH
	if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
	    auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
		debug("Approval failure for %s", user);
		pw = NULL;
	}
	if (as != NULL)
		auth_close(as);
#endif
#endif
	if (pw != NULL)
		return (pwcopy(pw));
	return (NULL);
}

void
auth_debug_add(const char *fmt,...)
{
	char buf[1024];
	va_list args;

	if (!auth_debug_init)
		return;

	va_start(args, fmt);
	vsnprintf(buf, sizeof(buf), fmt, args);
	va_end(args);
	buffer_put_cstring(&auth_debug, buf);
}

void
auth_debug_send(void)
{
	char *msg;

	if (!auth_debug_init)
		return;
	while (buffer_len(&auth_debug)) {
		msg = buffer_get_string(&auth_debug, NULL);
		packet_send_debug("%s", msg);
		xfree(msg);
	}
}

void
auth_debug_reset(void)
{
	if (auth_debug_init)
		buffer_clear(&auth_debug);
	else {
		buffer_init(&auth_debug);
		auth_debug_init = 1;
	}
}

struct passwd *
fakepw(void)
{
	static struct passwd fake;

	memset(&fake, 0, sizeof(fake));
	fake.pw_name = "NOUSER";
	fake.pw_passwd =
	    "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
	fake.pw_gecos = "NOUSER";
	fake.pw_uid = privsep_pw->pw_uid;
	fake.pw_gid = privsep_pw->pw_gid;
#ifdef HAVE_PW_CLASS_IN_PASSWD
	fake.pw_class = "";
#endif
	fake.pw_dir = "/nonexist";
	fake.pw_shell = "/nonexist";

	return (&fake);
}
Commit	Line	Data
2e437378	1	/* $OpenBSD: auth.c,v 1.75 2006/08/03 03:34:41 deraadt Exp $ */
3c0ef626	2	/*
	3	* Copyright (c) 2000 Markus Friedl. All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
	13	*
	14	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	15	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	16	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	17	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	18	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	19	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	20	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	21	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	22	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	23	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	24	*/
	25
	26	#include "includes.h"
3c0ef626	27
2e437378	28	#include <sys/types.h>
	29	#include <sys/stat.h>
	30	#include <sys/param.h>
	31
	32	#include <netinet/in.h>
	33
	34	#include <errno.h>
	35	#ifdef HAVE_PATHS_H
	36	# include <paths.h>
	37	#endif
	38	#include <pwd.h>
3c0ef626	39	#ifdef HAVE_LOGIN_H
	40	#include <login.h>
	41	#endif
416fd2a8	42	#ifdef USE_SHADOW
3c0ef626	43	#include <shadow.h>
416fd2a8	44	#endif
3c0ef626	45	#ifdef HAVE_LIBGEN_H
	46	#include <libgen.h>
	47	#endif
2e437378	48	#include <stdarg.h>
	49	#include <stdio.h>
	50	#include <string.h>
3c0ef626	51
	52	#include "xmalloc.h"
	53	#include "match.h"
	54	#include "groupaccess.h"
	55	#include "log.h"
2e437378	56	#include "buffer.h"
3c0ef626	57	#include "servconf.h"
2e437378	58	#include "key.h"
2e437378	59	#include "hostfile.h"
3c0ef626	60	#include "auth.h"
	61	#include "auth-options.h"
	62	#include "canohost.h"
3c0ef626	63	#include "uidswap.h"
2980ea68	64	#include "misc.h"
2980ea68	65	#include "packet.h"
34fee935	66	#include "loginrec.h"
2e437378	67	#ifdef GSSAPI
	68	#include "ssh-gss.h"
	69	#endif
34fee935	70	#include "monitor_wrap.h"
3c0ef626	71
	72	/* import */
	73	extern ServerOptions options;
2e437378	74	extern int use_privsep;
70791e56	75	extern Buffer loginmsg;
2e437378	76	extern struct passwd *privsep_pw;
3c0ef626	77
2980ea68	78	/* Debugging messages */
	79	Buffer auth_debug;
	80	int auth_debug_init;
	81
3c0ef626	82	/*
	83	* Check if the user is allowed to log in via ssh. If user is listed
	84	* in DenyUsers or one of user's groups is listed in DenyGroups, false
	85	* will be returned. If AllowUsers isn't empty and user isn't listed
	86	* there, or if AllowGroups isn't empty and one of user's groups isn't
	87	* listed there, false will be returned.
	88	* If the user's shell is not executable, false will be returned.
	89	* Otherwise true is returned.
	90	*/
	91	int
	92	allowed_user(struct passwd * pw)
	93	{
	94	struct stat st;
70791e56	95	const char hostname = NULL, ipaddr = NULL, *passwd = NULL;
3c0ef626	96	char *shell;
34fee935	97	u_int i;
416fd2a8	98	#ifdef USE_SHADOW
70791e56	99	struct spwd *spw = NULL;
1c14df9e	100	#endif
3c0ef626	101
	102	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
	103	if (!pw \|\| !pw->pw_name)
	104	return 0;
	105
416fd2a8	106	#ifdef USE_SHADOW
70791e56	107	if (!options.use_pam)
	108	spw = getspnam(pw->pw_name);
	109	#ifdef HAS_SHADOW_EXPIRE
416fd2a8	110	if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
416fd2a8	111	return 0;
70791e56	112	#endif /* HAS_SHADOW_EXPIRE */
416fd2a8	113	#endif /* USE_SHADOW */
70791e56	114
416fd2a8	115	/* grab passwd field for locked account check */
416fd2a8	116	#ifdef USE_SHADOW
70791e56	117	if (spw != NULL)
34fee935	118	#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
	119	passwd = get_iaf_password(pw);
	120	#else
70791e56	121	passwd = spw->sp_pwdp;
34fee935	122	#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
70791e56	123	#else
70791e56	124	passwd = pw->pw_passwd;
3c0ef626	125	#endif
3c0ef626	126
416fd2a8	127	/* check for locked account */
70791e56	128	if (!options.use_pam && passwd && *passwd) {
	129	int locked = 0;
	130
	131	#ifdef LOCKED_PASSWD_STRING
	132	if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
	133	locked = 1;
	134	#endif
	135	#ifdef LOCKED_PASSWD_PREFIX
	136	if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
	137	strlen(LOCKED_PASSWD_PREFIX)) == 0)
	138	locked = 1;
	139	#endif
	140	#ifdef LOCKED_PASSWD_SUBSTR
	141	if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
	142	locked = 1;
	143	#endif
34fee935	144	#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
	145	free(passwd);
	146	#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
70791e56	147	if (locked) {
	148	logit("User %.100s not allowed because account is locked",
	149	pw->pw_name);
	150	return 0;
	151	}
	152	}
	153
3c0ef626	154	/*
	155	* Get the shell from the password data. An empty shell field is
	156	* legal, and means /bin/sh.
	157	*/
	158	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
	159
	160	/* deny if shell does not exists or is not executable */
e9a17296	161	if (stat(shell, &st) != 0) {
70791e56	162	logit("User %.100s not allowed because shell %.100s does not exist",
e9a17296	163	pw->pw_name, shell);
3c0ef626	164	return 0;
e9a17296	165	}
2980ea68	166	if (S_ISREG(st.st_mode) == 0 \|\|
2980ea68	167	(st.st_mode & (S_IXOTH\|S_IXUSR\|S_IXGRP)) == 0) {
70791e56	168	logit("User %.100s not allowed because shell %.100s is not executable",
e9a17296	169	pw->pw_name, shell);
3c0ef626	170	return 0;
e9a17296	171	}
3c0ef626	172
34fee935	173	if (options.num_deny_users > 0 \|\| options.num_allow_users > 0 \|\|
34fee935	174	options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
70791e56	175	hostname = get_canonical_hostname(options.use_dns);
3c0ef626	176	ipaddr = get_remote_ipaddr();
	177	}
	178
	179	/* Return false if user is listed in DenyUsers */
	180	if (options.num_deny_users > 0) {
	181	for (i = 0; i < options.num_deny_users; i++)
2980ea68	182	if (match_user(pw->pw_name, hostname, ipaddr,
e9a17296	183	options.deny_users[i])) {
34fee935	184	logit("User %.100s from %.100s not allowed "
	185	"because listed in DenyUsers",
	186	pw->pw_name, hostname);
3c0ef626	187	return 0;
e9a17296	188	}
3c0ef626	189	}
	190	/* Return false if AllowUsers isn't empty and user isn't listed there */
	191	if (options.num_allow_users > 0) {
	192	for (i = 0; i < options.num_allow_users; i++)
078f71c2	193	if (match_user(pw->pw_name, hostname, ipaddr,
3c0ef626	194	options.allow_users[i]))
	195	break;
	196	/* i < options.num_allow_users iff we break for loop */
e9a17296	197	if (i >= options.num_allow_users) {
34fee935	198	logit("User %.100s from %.100s not allowed because "
34fee935	199	"not listed in AllowUsers", pw->pw_name, hostname);
3c0ef626	200	return 0;
e9a17296	201	}
3c0ef626	202	}
	203	if (options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
	204	/* Get the user's group access list (primary and supplementary) */
e9a17296	205	if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
34fee935	206	logit("User %.100s from %.100s not allowed because "
34fee935	207	"not in any group", pw->pw_name, hostname);
3c0ef626	208	return 0;
e9a17296	209	}
3c0ef626	210
	211	/* Return false if one of user's groups is listed in DenyGroups */
	212	if (options.num_deny_groups > 0)
	213	if (ga_match(options.deny_groups,
	214	options.num_deny_groups)) {
	215	ga_free();
34fee935	216	logit("User %.100s from %.100s not allowed "
	217	"because a group is listed in DenyGroups",
	218	pw->pw_name, hostname);
3c0ef626	219	return 0;
	220	}
	221	/*
	222	* Return false if AllowGroups isn't empty and one of user's groups
	223	* isn't listed there
	224	*/
	225	if (options.num_allow_groups > 0)
	226	if (!ga_match(options.allow_groups,
	227	options.num_allow_groups)) {
	228	ga_free();
34fee935	229	logit("User %.100s from %.100s not allowed "
	230	"because none of user's groups are listed "
	231	"in AllowGroups", pw->pw_name, hostname);
3c0ef626	232	return 0;
	233	}
	234	ga_free();
	235	}
	236
1b56ff3d	237	#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
34fee935	238	if (!sys_auth_allowed_user(pw, &loginmsg))
1b56ff3d	239	return 0;
1b56ff3d	240	#endif
3c0ef626	241
	242	/* We found no reason not to let this user try to log on... */
	243	return 1;
	244	}
	245
3c0ef626	246	void
	247	auth_log(Authctxt authctxt, int authenticated, char method, char *info)
	248	{
	249	void (authlog) (const char fmt,...) = verbose;
	250	char *authmsg;
	251
2e437378	252	if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
	253	return;
	254
3c0ef626	255	/* Raise logging level */
	256	if (authenticated == 1 \|\|
	257	!authctxt->valid \|\|
1b56ff3d	258	authctxt->failures >= options.max_authtries / 2 \|\|
3c0ef626	259	strcmp(method, "password") == 0)
70791e56	260	authlog = logit;
3c0ef626	261
	262	if (authctxt->postponed)
	263	authmsg = "Postponed";
	264	else
	265	authmsg = authenticated ? "Accepted" : "Failed";
	266
	267	authlog("%s %s for %s%.100s from %.200s port %d%s",
	268	authmsg,
	269	method,
1b56ff3d	270	authctxt->valid ? "" : "invalid user ",
1b56ff3d	271	(authctxt->user && authctxt->user[0]) ?
d370c64b	272	authctxt->user : "unknown",
3c0ef626	273	get_remote_ipaddr(),
	274	get_remote_port(),
	275	info);
e54b3d7c	276
70791e56	277	#ifdef CUSTOM_FAILED_LOGIN
34fee935	278	if (authenticated == 0 && !authctxt->postponed &&
	279	(strcmp(method, "password") == 0 \|\|
	280	strncmp(method, "keyboard-interactive", 20) == 0 \|\|
	281	strcmp(method, "challenge-response") == 0))
	282	record_failed_login(authctxt->user,
	283	get_canonical_hostname(options.use_dns), "ssh");
2e437378	284	# ifdef WITH_AIXAUTHENTICATE
	285	if (authenticated)
	286	sys_auth_record_login(authctxt->user,
	287	get_canonical_hostname(options.use_dns), "ssh", &loginmsg);
	288	# endif
34fee935	289	#endif
34fee935	290	#ifdef SSH_AUDIT_EVENTS
2e437378	291	if (authenticated == 0 && !authctxt->postponed)
2e437378	292	audit_event(audit_classify_auth(method));
70791e56	293	#endif
3c0ef626	294	}
	295
	296	/*
	297	* Check whether root logins are disallowed.
	298	*/
	299	int
	300	auth_root_allowed(char *method)
	301	{
	302	switch (options.permit_root_login) {
	303	case PERMIT_YES:
	304	return 1;
3c0ef626	305	case PERMIT_NO_PASSWD:
	306	if (strcmp(method, "password") != 0)
	307	return 1;
	308	break;
	309	case PERMIT_FORCED_ONLY:
	310	if (forced_command) {
70791e56	311	logit("Root login accepted for forced command.");
3c0ef626	312	return 1;
	313	}
	314	break;
	315	}
70791e56	316	logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
3c0ef626	317	return 0;
	318	}
	319
	320
	321	/*
	322	* Given a template and a passwd structure, build a filename
	323	* by substituting % tokenised options. Currently, %% becomes '%',
	324	* %h becomes the home directory and %u the username.
	325	*
	326	* This returns a buffer allocated by xmalloc.
	327	*/
2e437378	328	char *
34fee935	329	expand_authorized_keys(const char filename, struct passwd pw)
3c0ef626	330	{
2e437378	331	char *file, ret[MAXPATHLEN];
2e437378	332	int i;
3c0ef626	333
34fee935	334	file = percent_expand(filename, "h", pw->pw_dir,
34fee935	335	"u", pw->pw_name, (char *)NULL);
3c0ef626	336
	337	/*
	338	* Ensure that filename starts anchored. If not, be backward
	339	* compatible and prepend the '%h/'
	340	*/
34fee935	341	if (*file == '/')
	342	return (file);
	343
2e437378	344	i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
2e437378	345	if (i < 0 \|\| (size_t)i >= sizeof(ret))
34fee935	346	fatal("expand_authorized_keys: path too long");
34fee935	347	xfree(file);
2e437378	348	return (xstrdup(ret));
3c0ef626	349	}
	350
	351	char *
	352	authorized_keys_file(struct passwd *pw)
	353	{
34fee935	354	return expand_authorized_keys(options.authorized_keys_file, pw);
3c0ef626	355	}
	356
	357	char *
	358	authorized_keys_file2(struct passwd *pw)
	359	{
34fee935	360	return expand_authorized_keys(options.authorized_keys_file2, pw);
3c0ef626	361	}
	362
	363	/* return ok if key exists in sysfile or userfile */
	364	HostStatus
	365	check_key_in_hostfiles(struct passwd pw, Key key, const char *host,
	366	const char sysfile, const char userfile)
	367	{
	368	Key *found;
	369	char *user_hostfile;
	370	struct stat st;
e9a17296	371	HostStatus host_status;
3c0ef626	372
	373	/* Check if we know the host and its host key. */
	374	found = key_new(key->type);
	375	host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
	376
	377	if (host_status != HOST_OK && userfile != NULL) {
	378	user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
	379	if (options.strict_modes &&
	380	(stat(user_hostfile, &st) == 0) &&
	381	((st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
e9a17296	382	(st.st_mode & 022) != 0)) {
70791e56	383	logit("Authentication refused for %.100s: "
3c0ef626	384	"bad owner or modes for %.200s",
	385	pw->pw_name, user_hostfile);
	386	} else {
	387	temporarily_use_uid(pw);
	388	host_status = check_host_in_hostfile(user_hostfile,
	389	host, key, found, NULL);
	390	restore_uid();
	391	}
	392	xfree(user_hostfile);
	393	}
	394	key_free(found);
	395
	396	debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
	397	"ok" : "not found", host);
	398	return host_status;
	399	}
	400
	401
	402	/*
	403	* Check a given file for security. This is defined as all components
e54b3d7c	404	* of the path to the file must be owned by either the owner of
3c0ef626	405	* of the file or root and no directories must be group or world writable.
	406	*
	407	* XXX Should any specific check be done for sym links ?
	408	*
	409	* Takes an open file descriptor, the file name, a uid and and
	410	* error buffer plus max size as arguments.
	411	*
	412	* Returns 0 on success and -1 on failure
	413	*/
	414	int
	415	secure_filename(FILE f, const char file, struct passwd *pw,
	416	char *err, size_t errlen)
	417	{
	418	uid_t uid = pw->pw_uid;
	419	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
	420	char *cp;
1c14df9e	421	int comparehome = 0;
3c0ef626	422	struct stat st;
	423
	424	if (realpath(file, buf) == NULL) {
	425	snprintf(err, errlen, "realpath %s failed: %s", file,
	426	strerror(errno));
	427	return -1;
	428	}
1c14df9e	429	if (realpath(pw->pw_dir, homedir) != NULL)
1c14df9e	430	comparehome = 1;
3c0ef626	431
	432	/* check the open file to avoid races */
	433	if (fstat(fileno(f), &st) < 0 \|\|
	434	(st.st_uid != 0 && st.st_uid != uid) \|\|
	435	(st.st_mode & 022) != 0) {
	436	snprintf(err, errlen, "bad ownership or modes for file %s",
	437	buf);
	438	return -1;
	439	}
	440
	441	/* for each component of the canonical path, walking upwards */
	442	for (;;) {
	443	if ((cp = dirname(buf)) == NULL) {
	444	snprintf(err, errlen, "dirname() failed");
	445	return -1;
	446	}
	447	strlcpy(buf, cp, sizeof(buf));
	448
	449	debug3("secure_filename: checking '%s'", buf);
	450	if (stat(buf, &st) < 0 \|\|
	451	(st.st_uid != 0 && st.st_uid != uid) \|\|
	452	(st.st_mode & 022) != 0) {
e9a17296	453	snprintf(err, errlen,
3c0ef626	454	"bad ownership or modes for directory %s", buf);
	455	return -1;
	456	}
	457
	458	/* If are passed the homedir then we can stop */
1c14df9e	459	if (comparehome && strcmp(homedir, buf) == 0) {
3c0ef626	460	debug3("secure_filename: terminating check at '%s'",
	461	buf);
	462	break;
	463	}
	464	/*
	465	* dirname should always complete with a "/" path,
	466	* but we can be paranoid and check for "." too
	467	*/
	468	if ((strcmp("/", buf) == 0) \|\| (strcmp(".", buf) == 0))
	469	break;
	470	}
	471	return 0;
	472	}
2980ea68	473
	474	struct passwd *
	475	getpwnamallow(const char *user)
	476	{
	477	#ifdef HAVE_LOGIN_CAP
	478	extern login_cap_t *lc;
	479	#ifdef BSD_AUTH
	480	auth_session_t *as;
	481	#endif
	482	#endif
	483	struct passwd *pw;
	484
2e437378	485	parse_server_match_config(&options, user,
	486	get_canonical_hostname(options.use_dns), get_remote_ipaddr());
	487
2980ea68	488	pw = getpwnam(user);
e54b3d7c	489	if (pw == NULL) {
1b56ff3d	490	logit("Invalid user %.100s from %.100s",
d370c64b	491	(user && user[0]) ? user : "unknown",
416fd2a8	492	get_remote_ipaddr());
70791e56	493	#ifdef CUSTOM_FAILED_LOGIN
34fee935	494	record_failed_login(user,
34fee935	495	get_canonical_hostname(options.use_dns), "ssh");
1c14df9e	496	#endif
34fee935	497	#ifdef SSH_AUDIT_EVENTS
	498	audit_event(SSH_INVALID_USER);
	499	#endif /* SSH_AUDIT_EVENTS */
e54b3d7c	500	return (NULL);
	501	}
	502	if (!allowed_user(pw))
2980ea68	503	return (NULL);
	504	#ifdef HAVE_LOGIN_CAP
	505	if ((lc = login_getclass(pw->pw_class)) == NULL) {
	506	debug("unable to get login class: %s", user);
	507	return (NULL);
	508	}
	509	#ifdef BSD_AUTH
	510	if ((as = auth_open()) == NULL \|\| auth_setpwd(as, pw) != 0 \|\|
	511	auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
	512	debug("Approval failure for %s", user);
	513	pw = NULL;
	514	}
	515	if (as != NULL)
	516	auth_close(as);
	517	#endif
	518	#endif
	519	if (pw != NULL)
	520	return (pwcopy(pw));
	521	return (NULL);
	522	}
	523
	524	void
	525	auth_debug_add(const char *fmt,...)
	526	{
	527	char buf[1024];
	528	va_list args;
	529
	530	if (!auth_debug_init)
	531	return;
	532
	533	va_start(args, fmt);
	534	vsnprintf(buf, sizeof(buf), fmt, args);
	535	va_end(args);
	536	buffer_put_cstring(&auth_debug, buf);
	537	}
	538
	539	void
	540	auth_debug_send(void)
	541	{
	542	char *msg;
	543
	544	if (!auth_debug_init)
	545	return;
	546	while (buffer_len(&auth_debug)) {
	547	msg = buffer_get_string(&auth_debug, NULL);
	548	packet_send_debug("%s", msg);
	549	xfree(msg);
	550	}
	551	}
	552
	553	void
	554	auth_debug_reset(void)
	555	{
	556	if (auth_debug_init)
	557	buffer_clear(&auth_debug);
	558	else {
	559	buffer_init(&auth_debug);
	560	auth_debug_init = 1;
	561	}
	562	}
70791e56	563
	564	struct passwd *
	565	fakepw(void)
	566	{
	567	static struct passwd fake;
	568
	569	memset(&fake, 0, sizeof(fake));
	570	fake.pw_name = "NOUSER";
	571	fake.pw_passwd =
416fd2a8	572	"$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
70791e56	573	fake.pw_gecos = "NOUSER";
2e437378	574	fake.pw_uid = privsep_pw->pw_uid;
2e437378	575	fake.pw_gid = privsep_pw->pw_gid;
70791e56	576	#ifdef HAVE_PW_CLASS_IN_PASSWD
	577	fake.pw_class = "";
	578	#endif
	579	fake.pw_dir = "/nonexist";
	580	fake.pw_shell = "/nonexist";
	581
	582	return (&fake);
	583	}