[openssh.git] / auth.c

/*
 * 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"
RCSID("$OpenBSD: auth.c,v 1.46 2002/11/04 10:07:53 markus Exp $");

#ifdef HAVE_LOGIN_H
#include <login.h>
#endif
#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
#include <shadow.h>
#endif /* defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) */

#ifdef HAVE_LIBGEN_H
#include <libgen.h>
#endif

#include "xmalloc.h"
#include "match.h"
#include "groupaccess.h"
#include "log.h"
#include "servconf.h"
#include "auth.h"
#include "auth-options.h"
#include "canohost.h"
#include "buffer.h"
#include "bufaux.h"
#include "uidswap.h"
#include "tildexpand.h"
#include "misc.h"
#include "bufaux.h"
#include "packet.h"

/* import */
extern ServerOptions options;

/* 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;
	char *shell;
	int i;
#ifdef WITH_AIXAUTHENTICATE
	char *loginmsg;
#endif /* WITH_AIXAUTHENTICATE */
#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
	struct spwd *spw;
#endif

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

	/* Grab the password for locked account checking */
#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
	spw = getspnam(pw->pw_name);
	if (!spw)
		return 0;
	passwd = spw->sp_pwdp;
#else
	passwd = pw->pw_passwd;
#endif

	/* check for locked account */
	if (strcmp(passwd, "*LK*") == 0 || passwd[0] == '!') {
		log("User %.100s not allowed because account is locked",
		    pw->pw_name);
		return 0;
	}

#if !defined(USE_PAM) && defined(HAVE_SHADOW_H) && \
    !defined(DISABLE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
#define	DAY		(24L * 60 * 60) /* 1 day in seconds */
	time_t today = time(NULL) / DAY;
	debug3("allowed_user: today %d sp_expire %d sp_lstchg %d"
	    " sp_max %d", (int)today, (int)spw->sp_expire,
	    (int)spw->sp_lstchg, (int)spw->sp_max);

	/*
	 * We assume account and password expiration occurs the
	 * day after the day specified.
	 */
	if (spw->sp_expire != -1 && today > spw->sp_expire) {
		log("Account %.100s has expired", pw->pw_name);
		return 0;
	}

	if (spw->sp_lstchg == 0) {
		log("User %.100s password has expired (root forced)",
		    pw->pw_name);
		return 0;
	}

	if (spw->sp_max != -1 &&
	    today > spw->sp_lstchg + spw->sp_max) {
		log("User %.100s password has expired (password aged)",
		    pw->pw_name);
		return 0;
	}
#endif

	/*
	 * 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) {
		log("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) {
		log("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) {
		hostname = get_canonical_hostname(options.verify_reverse_mapping);
		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])) {
				log("User %.100s not allowed because listed in DenyUsers",
				    pw->pw_name);
				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) {
			log("User %.100s not allowed because not listed in AllowUsers",
			    pw->pw_name);
			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) {
			log("User %.100s not allowed because not in any group",
			    pw->pw_name);
			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();
				log("User %.100s not allowed because a group is listed in DenyGroups",
				    pw->pw_name);
				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();
				log("User %.100s not allowed because none of user's groups are listed in AllowGroups",
				    pw->pw_name);
				return 0;
			}
		ga_free();
	}

#ifdef WITH_AIXAUTHENTICATE
	/*
	 * Don't check loginrestrictions() for root account (use
	 * PermitRootLogin to control logins via ssh), or if running as
	 * non-root user (since loginrestrictions will always fail).
	 */
	if ( (pw->pw_uid != 0) && (geteuid() == 0) &&
	    loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &loginmsg) != 0) {
		int loginrestrict_errno = errno;

		if (loginmsg && *loginmsg) {
			/* Remove embedded newlines (if any) */
			char *p;
			for (p = loginmsg; *p; p++) {
				if (*p == '\n')
					*p = ' ';
			}
			/* Remove trailing newline */
			*--p = '\0';
			log("Login restricted for %s: %.100s", pw->pw_name, 
			    loginmsg);
		}
		/* Don't fail if /etc/nologin  set */
	    	if (!(loginrestrict_errno == EPERM && 
		    stat(_PATH_NOLOGIN, &st) == 0))
			return 0;
	}
#endif /* WITH_AIXAUTHENTICATE */

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

Authctxt *
authctxt_new(void)
{
	Authctxt *authctxt = xmalloc(sizeof(*authctxt));
	memset(authctxt, 0, sizeof(*authctxt));
	return authctxt;
}

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

	/* Raise logging level */
	if (authenticated == 1 ||
	    !authctxt->valid ||
	    authctxt->failures >= AUTH_FAIL_LOG ||
	    strcmp(method, "password") == 0)
		authlog = log;

	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 ? "" : "illegal user ",
	    authctxt->user,
	    get_remote_ipaddr(),
	    get_remote_port(),
	    info);

#ifdef WITH_AIXAUTHENTICATE
	if (authenticated == 0 && strcmp(method, "password") == 0)
	    loginfailed(authctxt->user,
		get_canonical_hostname(options.verify_reverse_mapping),
		"ssh");
#endif /* WITH_AIXAUTHENTICATE */

}

/*
 * Check whether root logins are disallowed.
 */
int
auth_root_allowed(char *method)
{
	switch (options.permit_root_login) {
	case PERMIT_YES:
		return 1;
		break;
	case PERMIT_NO_PASSWD:
		if (strcmp(method, "password") != 0)
			return 1;
		break;
	case PERMIT_FORCED_ONLY:
		if (forced_command) {
			log("Root login accepted for forced command.");
			return 1;
		}
		break;
	}
	log("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_filename(const char *filename, struct passwd *pw)
{
	Buffer buffer;
	char *file;
	const char *cp;

	/*
	 * Build the filename string in the buffer by making the appropriate
	 * substitutions to the given file name.
	 */
	buffer_init(&buffer);
	for (cp = filename; *cp; cp++) {
		if (cp[0] == '%' && cp[1] == '%') {
			buffer_append(&buffer, "%", 1);
			cp++;
			continue;
		}
		if (cp[0] == '%' && cp[1] == 'h') {
			buffer_append(&buffer, pw->pw_dir, strlen(pw->pw_dir));
			cp++;
			continue;
		}
		if (cp[0] == '%' && cp[1] == 'u') {
			buffer_append(&buffer, pw->pw_name,
			    strlen(pw->pw_name));
			cp++;
			continue;
		}
		buffer_append(&buffer, cp, 1);
	}
	buffer_append(&buffer, "\0", 1);

	/*
	 * Ensure that filename starts anchored. If not, be backward
	 * compatible and prepend the '%h/'
	 */
	file = xmalloc(MAXPATHLEN);
	cp = buffer_ptr(&buffer);
	if (*cp != '/')
		snprintf(file, MAXPATHLEN, "%s/%s", pw->pw_dir, cp);
	else
		strlcpy(file, cp, MAXPATHLEN);

	buffer_free(&buffer);
	return file;
}

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

char *
authorized_keys_file2(struct passwd *pw)
{
	return expand_filename(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)) {
			log("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;

	pw = getpwnam(user);
	if (pw == NULL) {
		log("Illegal user %.100s from %.100s",
		    user, get_remote_ipaddr());
#ifdef WITH_AIXAUTHENTICATE
		loginfailed(user,
		    get_canonical_hostname(options.verify_reverse_mapping),
		    "ssh");
#endif
		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;
	}
}
Commit	Line	Data
20d0f77f	1	/*
f3c7c613	2	* Copyright (c) 2000 Markus Friedl. All rights reserved.
bcbf86ec	3	*
	4	* Redistribution and use in source and binary forms, with or without
	5	* modification, are permitted provided that the following conditions
	6	* are met:
	7	* 1. Redistributions of source code must retain the above copyright
	8	* notice, this list of conditions and the following disclaimer.
	9	* 2. Redistributions in binary form must reproduce the above copyright
	10	* notice, this list of conditions and the following disclaimer in the
	11	* documentation and/or other materials provided with the distribution.
	12	*
	13	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	14	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	15	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	16	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	17	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	18	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	19	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	20	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	21	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	22	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
7368a6c8	23	*/
	24
	25	#include "includes.h"
f6f02456	26	RCSID("$OpenBSD: auth.c,v 1.46 2002/11/04 10:07:53 markus Exp $");
7368a6c8	27
c1ef8333	28	#ifdef HAVE_LOGIN_H
	29	#include <login.h>
	30	#endif
4cb5ffa0	31	#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
	32	#include <shadow.h>
	33	#endif /* defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) */
7368a6c8	34
b4d02860	35	#ifdef HAVE_LIBGEN_H
c8445989	36	#include <libgen.h>
b4d02860	37	#endif
c8445989	38
42f11eb2	39	#include "xmalloc.h"
	40	#include "match.h"
	41	#include "groupaccess.h"
	42	#include "log.h"
	43	#include "servconf.h"
e78a59f5	44	#include "auth.h"
59c97189	45	#include "auth-options.h"
42f11eb2	46	#include "canohost.h"
c8445989	47	#include "buffer.h"
c8445989	48	#include "bufaux.h"
d0c8ca5c	49	#include "uidswap.h"
d0c8ca5c	50	#include "tildexpand.h"
5f1f36b5	51	#include "misc.h"
01dafcb5	52	#include "bufaux.h"
01dafcb5	53	#include "packet.h"
e78a59f5	54
7368a6c8	55	/* import */
7368a6c8	56	extern ServerOptions options;
7368a6c8	57
01dafcb5	58	/* Debugging messages */
	59	Buffer auth_debug;
	60	int auth_debug_init;
	61
7368a6c8	62	/*
c6a69271	63	* Check if the user is allowed to log in via ssh. If user is listed
	64	* in DenyUsers or one of user's groups is listed in DenyGroups, false
	65	* will be returned. If AllowUsers isn't empty and user isn't listed
	66	* there, or if AllowGroups isn't empty and one of user's groups isn't
	67	* listed there, false will be returned.
7368a6c8	68	* If the user's shell is not executable, false will be returned.
6ae2364d	69	* Otherwise true is returned.
7368a6c8	70	*/
a306f2dd	71	int
7368a6c8	72	allowed_user(struct passwd * pw)
	73	{
	74	struct stat st;
e2ef2342	75	const char hostname = NULL, ipaddr = NULL, *passwd;
614dee3a	76	char *shell;
7368a6c8	77	int i;
	78	#ifdef WITH_AIXAUTHENTICATE
	79	char *loginmsg;
	80	#endif /* WITH_AIXAUTHENTICATE */
b57c8e20	81	#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
c6a69271	82	struct spwd *spw;
e2ef2342	83	#endif
7368a6c8	84
7368a6c8	85	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
c6a69271	86	if (!pw \|\| !pw->pw_name)
7368a6c8	87	return 0;
7368a6c8	88
b57c8e20	89	/* Grab the password for locked account checking */
b57c8e20	90	#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
4cb5ffa0	91	spw = getspnam(pw->pw_name);
b57c8e20	92	if (!spw)
b57c8e20	93	return 0;
e2ef2342	94	passwd = spw->sp_pwdp;
4cb5ffa0	95	#else
e2ef2342	96	passwd = pw->pw_passwd;
4cb5ffa0	97	#endif
93a9a35a	98
e2ef2342	99	/* check for locked account */
	100	if (strcmp(passwd, "LK") == 0 \|\| passwd[0] == '!') {
	101	log("User %.100s not allowed because account is locked",
	102	pw->pw_name);
	103	return 0;
	104	}
4cb5ffa0	105
b57c8e20	106	#if !defined(USE_PAM) && defined(HAVE_SHADOW_H) && \
	107	!defined(DISABLE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
	108	#define DAY (24L * 60 * 60) /* 1 day in seconds */
	109	time_t today = time(NULL) / DAY;
	110	debug3("allowed_user: today %d sp_expire %d sp_lstchg %d"
	111	" sp_max %d", (int)today, (int)spw->sp_expire,
	112	(int)spw->sp_lstchg, (int)spw->sp_max);
	113
	114	/*
	115	* We assume account and password expiration occurs the
	116	* day after the day specified.
	117	*/
	118	if (spw->sp_expire != -1 && today > spw->sp_expire) {
	119	log("Account %.100s has expired", pw->pw_name);
	120	return 0;
	121	}
	122
	123	if (spw->sp_lstchg == 0) {
	124	log("User %.100s password has expired (root forced)",
	125	pw->pw_name);
	126	return 0;
	127	}
	128
	129	if (spw->sp_max != -1 &&
	130	today > spw->sp_lstchg + spw->sp_max) {
	131	log("User %.100s password has expired (password aged)",
	132	pw->pw_name);
	133	return 0;
	134	}
	135	#endif
	136
301e9b01	137	/*
	138	* Get the shell from the password data. An empty shell field is
	139	* legal, and means /bin/sh.
	140	*/
	141	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
	142
	143	/* deny if shell does not exists or is not executable */
b334badd	144	if (stat(shell, &st) != 0) {
	145	log("User %.100s not allowed because shell %.100s does not exist",
	146	pw->pw_name, shell);
7368a6c8	147	return 0;
b334badd	148	}
c390a3c8	149	if (S_ISREG(st.st_mode) == 0 \|\|
c390a3c8	150	(st.st_mode & (S_IXOTH\|S_IXUSR\|S_IXGRP)) == 0) {
b334badd	151	log("User %.100s not allowed because shell %.100s is not executable",
b334badd	152	pw->pw_name, shell);
7368a6c8	153	return 0;
b334badd	154	}
7368a6c8	155
6805fc56	156	if (options.num_deny_users > 0 \|\| options.num_allow_users > 0) {
	157	hostname = get_canonical_hostname(options.verify_reverse_mapping);
	158	ipaddr = get_remote_ipaddr();
	159	}
	160
7368a6c8	161	/* Return false if user is listed in DenyUsers */
7368a6c8	162	if (options.num_deny_users > 0) {
7368a6c8	163	for (i = 0; i < options.num_deny_users; i++)
762715ce	164	if (match_user(pw->pw_name, hostname, ipaddr,
b334badd	165	options.deny_users[i])) {
762715ce	166	log("User %.100s not allowed because listed in DenyUsers",
762715ce	167	pw->pw_name);
7368a6c8	168	return 0;
b334badd	169	}
7368a6c8	170	}
	171	/* Return false if AllowUsers isn't empty and user isn't listed there */
	172	if (options.num_allow_users > 0) {
7368a6c8	173	for (i = 0; i < options.num_allow_users; i++)
762715ce	174	if (match_user(pw->pw_name, hostname, ipaddr,
80f8f24f	175	options.allow_users[i]))
7368a6c8	176	break;
7368a6c8	177	/* i < options.num_allow_users iff we break for loop */
b334badd	178	if (i >= options.num_allow_users) {
	179	log("User %.100s not allowed because not listed in AllowUsers",
	180	pw->pw_name);
7368a6c8	181	return 0;
b334badd	182	}
7368a6c8	183	}
7368a6c8	184	if (options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
c6a69271	185	/* Get the user's group access list (primary and supplementary) */
b334badd	186	if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
	187	log("User %.100s not allowed because not in any group",
	188	pw->pw_name);
7368a6c8	189	return 0;
b334badd	190	}
7368a6c8	191
c6a69271	192	/* Return false if one of user's groups is listed in DenyGroups */
	193	if (options.num_deny_groups > 0)
	194	if (ga_match(options.deny_groups,
	195	options.num_deny_groups)) {
	196	ga_free();
b334badd	197	log("User %.100s not allowed because a group is listed in DenyGroups",
b334badd	198	pw->pw_name);
7368a6c8	199	return 0;
c6a69271	200	}
7368a6c8	201	/*
c6a69271	202	* Return false if AllowGroups isn't empty and one of user's groups
7368a6c8	203	* isn't listed there
7368a6c8	204	*/
c6a69271	205	if (options.num_allow_groups > 0)
	206	if (!ga_match(options.allow_groups,
	207	options.num_allow_groups)) {
	208	ga_free();
b334badd	209	log("User %.100s not allowed because none of user's groups are listed in AllowGroups",
b334badd	210	pw->pw_name);
7368a6c8	211	return 0;
c6a69271	212	}
c6a69271	213	ga_free();
7368a6c8	214	}
	215
	216	#ifdef WITH_AIXAUTHENTICATE
f3e87063	217	/*
	218	* Don't check loginrestrictions() for root account (use
	219	* PermitRootLogin to control logins via ssh), or if running as
	220	* non-root user (since loginrestrictions will always fail).
	221	*/
	222	if ( (pw->pw_uid != 0) && (geteuid() == 0) &&
	223	loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &loginmsg) != 0) {
99f4fb69	224	int loginrestrict_errno = errno;
99f4fb69	225
c1ef8333	226	if (loginmsg && *loginmsg) {
	227	/* Remove embedded newlines (if any) */
	228	char *p;
5daf7064	229	for (p = loginmsg; *p; p++) {
c1ef8333	230	if (*p == '\n')
c1ef8333	231	*p = ' ';
5daf7064	232	}
c1ef8333	233	/* Remove trailing newline */
c1ef8333	234	*--p = '\0';
99f4fb69	235	log("Login restricted for %s: %.100s", pw->pw_name,
99f4fb69	236	loginmsg);
c1ef8333	237	}
99f4fb69	238	/* Don't fail if /etc/nologin set */
	239	if (!(loginrestrict_errno == EPERM &&
	240	stat(_PATH_NOLOGIN, &st) == 0))
	241	return 0;
c1ef8333	242	}
7368a6c8	243	#endif /* WITH_AIXAUTHENTICATE */
	244
	245	/* We found no reason not to let this user try to log on... */
	246	return 1;
	247	}
59c97189	248
	249	Authctxt *
	250	authctxt_new(void)
	251	{
2b87da3b	252	Authctxt authctxt = xmalloc(sizeof(authctxt));
	253	memset(authctxt, 0, sizeof(*authctxt));
	254	return authctxt;
59c97189	255	}
59c97189	256
59c97189	257	void
	258	auth_log(Authctxt authctxt, int authenticated, char method, char *info)
	259	{
	260	void (authlog) (const char fmt,...) = verbose;
	261	char *authmsg;
	262
	263	/* Raise logging level */
	264	if (authenticated == 1 \|\|
	265	!authctxt->valid \|\|
	266	authctxt->failures >= AUTH_FAIL_LOG \|\|
	267	strcmp(method, "password") == 0)
	268	authlog = log;
	269
	270	if (authctxt->postponed)
	271	authmsg = "Postponed";
	272	else
	273	authmsg = authenticated ? "Accepted" : "Failed";
	274
	275	authlog("%s %s for %s%.100s from %.200s port %d%s",
	276	authmsg,
	277	method,
	278	authctxt->valid ? "" : "illegal user ",
fad3754c	279	authctxt->user,
59c97189	280	get_remote_ipaddr(),
	281	get_remote_port(),
	282	info);
56fd97d7	283
	284	#ifdef WITH_AIXAUTHENTICATE
	285	if (authenticated == 0 && strcmp(method, "password") == 0)
	286	loginfailed(authctxt->user,
	287	get_canonical_hostname(options.verify_reverse_mapping),
	288	"ssh");
	289	#endif /* WITH_AIXAUTHENTICATE */
	290
59c97189	291	}
	292
	293	/*
15853e93	294	* Check whether root logins are disallowed.
59c97189	295	*/
59c97189	296	int
15853e93	297	auth_root_allowed(char *method)
59c97189	298	{
15853e93	299	switch (options.permit_root_login) {
15853e93	300	case PERMIT_YES:
59c97189	301	return 1;
15853e93	302	break;
	303	case PERMIT_NO_PASSWD:
	304	if (strcmp(method, "password") != 0)
	305	return 1;
	306	break;
	307	case PERMIT_FORCED_ONLY:
	308	if (forced_command) {
	309	log("Root login accepted for forced command.");
	310	return 1;
	311	}
	312	break;
59c97189	313	}
15853e93	314	log("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
15853e93	315	return 0;
59c97189	316	}
c8445989	317
	318
	319	/*
	320	* Given a template and a passwd structure, build a filename
	321	* by substituting % tokenised options. Currently, %% becomes '%',
	322	* %h becomes the home directory and %u the username.
	323	*
	324	* This returns a buffer allocated by xmalloc.
	325	*/
	326	char *
	327	expand_filename(const char filename, struct passwd pw)
	328	{
	329	Buffer buffer;
	330	char *file;
	331	const char *cp;
	332
	333	/*
	334	* Build the filename string in the buffer by making the appropriate
	335	* substitutions to the given file name.
	336	*/
	337	buffer_init(&buffer);
	338	for (cp = filename; *cp; cp++) {
	339	if (cp[0] == '%' && cp[1] == '%') {
	340	buffer_append(&buffer, "%", 1);
	341	cp++;
	342	continue;
	343	}
	344	if (cp[0] == '%' && cp[1] == 'h') {
	345	buffer_append(&buffer, pw->pw_dir, strlen(pw->pw_dir));
	346	cp++;
	347	continue;
	348	}
	349	if (cp[0] == '%' && cp[1] == 'u') {
	350	buffer_append(&buffer, pw->pw_name,
184eed6a	351	strlen(pw->pw_name));
c8445989	352	cp++;
	353	continue;
	354	}
	355	buffer_append(&buffer, cp, 1);
	356	}
	357	buffer_append(&buffer, "\0", 1);
	358
	359	/*
	360	* Ensure that filename starts anchored. If not, be backward
	361	* compatible and prepend the '%h/'
	362	*/
	363	file = xmalloc(MAXPATHLEN);
	364	cp = buffer_ptr(&buffer);
	365	if (*cp != '/')
	366	snprintf(file, MAXPATHLEN, "%s/%s", pw->pw_dir, cp);
	367	else
	368	strlcpy(file, cp, MAXPATHLEN);
	369
	370	buffer_free(&buffer);
	371	return file;
	372	}
	373
	374	char *
	375	authorized_keys_file(struct passwd *pw)
	376	{
	377	return expand_filename(options.authorized_keys_file, pw);
	378	}
	379
	380	char *
	381	authorized_keys_file2(struct passwd *pw)
	382	{
	383	return expand_filename(options.authorized_keys_file2, pw);
	384	}
	385
d0c8ca5c	386	/* return ok if key exists in sysfile or userfile */
	387	HostStatus
	388	check_key_in_hostfiles(struct passwd pw, Key key, const char *host,
	389	const char sysfile, const char userfile)
	390	{
	391	Key *found;
	392	char *user_hostfile;
	393	struct stat st;
17a3011c	394	HostStatus host_status;
d0c8ca5c	395
	396	/* Check if we know the host and its host key. */
	397	found = key_new(key->type);
	398	host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
	399
	400	if (host_status != HOST_OK && userfile != NULL) {
	401	user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
	402	if (options.strict_modes &&
	403	(stat(user_hostfile, &st) == 0) &&
	404	((st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
184eed6a	405	(st.st_mode & 022) != 0)) {
d0c8ca5c	406	log("Authentication refused for %.100s: "
	407	"bad owner or modes for %.200s",
	408	pw->pw_name, user_hostfile);
	409	} else {
	410	temporarily_use_uid(pw);
	411	host_status = check_host_in_hostfile(user_hostfile,
	412	host, key, found, NULL);
	413	restore_uid();
	414	}
	415	xfree(user_hostfile);
	416	}
	417	key_free(found);
	418
	419	debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
	420	"ok" : "not found", host);
	421	return host_status;
	422	}
	423
	424
c8445989	425	/*
c8445989	426	* Check a given file for security. This is defined as all components
d6097023	427	* of the path to the file must be owned by either the owner of
1ddf764b	428	* of the file or root and no directories must be group or world writable.
c8445989	429	*
	430	* XXX Should any specific check be done for sym links ?
	431	*
	432	* Takes an open file descriptor, the file name, a uid and and
	433	* error buffer plus max size as arguments.
	434	*
	435	* Returns 0 on success and -1 on failure
	436	*/
	437	int
6978866a	438	secure_filename(FILE f, const char file, struct passwd *pw,
6978866a	439	char *err, size_t errlen)
c8445989	440	{
6978866a	441	uid_t uid = pw->pw_uid;
76fbdd47	442	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
c8445989	443	char *cp;
f6f02456	444	int comparehome = 0;
c8445989	445	struct stat st;
	446
	447	if (realpath(file, buf) == NULL) {
	448	snprintf(err, errlen, "realpath %s failed: %s", file,
	449	strerror(errno));
	450	return -1;
	451	}
f6f02456	452	if (realpath(pw->pw_dir, homedir) != NULL)
f6f02456	453	comparehome = 1;
c8445989	454
	455	/* check the open file to avoid races */
	456	if (fstat(fileno(f), &st) < 0 \|\|
	457	(st.st_uid != 0 && st.st_uid != uid) \|\|
	458	(st.st_mode & 022) != 0) {
	459	snprintf(err, errlen, "bad ownership or modes for file %s",
	460	buf);
	461	return -1;
	462	}
	463
	464	/* for each component of the canonical path, walking upwards */
	465	for (;;) {
	466	if ((cp = dirname(buf)) == NULL) {
	467	snprintf(err, errlen, "dirname() failed");
	468	return -1;
	469	}
	470	strlcpy(buf, cp, sizeof(buf));
	471
	472	debug3("secure_filename: checking '%s'", buf);
	473	if (stat(buf, &st) < 0 \|\|
	474	(st.st_uid != 0 && st.st_uid != uid) \|\|
	475	(st.st_mode & 022) != 0) {
184eed6a	476	snprintf(err, errlen,
c8445989	477	"bad ownership or modes for directory %s", buf);
	478	return -1;
	479	}
	480
afd501f9	481	/* If are passed the homedir then we can stop */
f6f02456	482	if (comparehome && strcmp(homedir, buf) == 0) {
afd501f9	483	debug3("secure_filename: terminating check at '%s'",
	484	buf);
	485	break;
	486	}
c8445989	487	/*
	488	* dirname should always complete with a "/" path,
	489	* but we can be paranoid and check for "." too
	490	*/
	491	if ((strcmp("/", buf) == 0) \|\| (strcmp(".", buf) == 0))
	492	break;
	493	}
	494	return 0;
	495	}
443fa1cd	496
	497	struct passwd *
	498	getpwnamallow(const char *user)
	499	{
1836f69f	500	#ifdef HAVE_LOGIN_CAP
	501	extern login_cap_t *lc;
	502	#ifdef BSD_AUTH
	503	auth_session_t *as;
	504	#endif
	505	#endif
443fa1cd	506	struct passwd *pw;
	507
	508	pw = getpwnam(user);
c2802d92	509	if (pw == NULL) {
	510	log("Illegal user %.100s from %.100s",
	511	user, get_remote_ipaddr());
819d3f09	512	#ifdef WITH_AIXAUTHENTICATE
	513	loginfailed(user,
	514	get_canonical_hostname(options.verify_reverse_mapping),
	515	"ssh");
	516	#endif
c2802d92	517	return (NULL);
	518	}
	519	if (!allowed_user(pw))
1836f69f	520	return (NULL);
	521	#ifdef HAVE_LOGIN_CAP
	522	if ((lc = login_getclass(pw->pw_class)) == NULL) {
	523	debug("unable to get login class: %s", user);
	524	return (NULL);
	525	}
	526	#ifdef BSD_AUTH
	527	if ((as = auth_open()) == NULL \|\| auth_setpwd(as, pw) != 0 \|\|
65721f9c	528	auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
1836f69f	529	debug("Approval failure for %s", user);
443fa1cd	530	pw = NULL;
1836f69f	531	}
	532	if (as != NULL)
	533	auth_close(as);
	534	#endif
	535	#endif
06bea668	536	if (pw != NULL)
	537	return (pwcopy(pw));
	538	return (NULL);
443fa1cd	539	}
01dafcb5	540
	541	void
	542	auth_debug_add(const char *fmt,...)
	543	{
	544	char buf[1024];
	545	va_list args;
	546
	547	if (!auth_debug_init)
	548	return;
	549
	550	va_start(args, fmt);
	551	vsnprintf(buf, sizeof(buf), fmt, args);
	552	va_end(args);
	553	buffer_put_cstring(&auth_debug, buf);
	554	}
	555
	556	void
	557	auth_debug_send(void)
	558	{
	559	char *msg;
	560
	561	if (!auth_debug_init)
	562	return;
	563	while (buffer_len(&auth_debug)) {
	564	msg = buffer_get_string(&auth_debug, NULL);
	565	packet_send_debug("%s", msg);
	566	xfree(msg);
	567	}
	568	}
	569
	570	void
	571	auth_debug_reset(void)
	572	{
	573	if (auth_debug_init)
	574	buffer_clear(&auth_debug);
	575	else {
	576	buffer_init(&auth_debug);
	577	auth_debug_init = 1;
	578	}
	579	}