[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 1.51 2003/11/21 11:57:02 djm 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;
extern Buffer loginmsg;

/* 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;
	int i;
#if defined(HAVE_SHADOW_H) && !defined(DISABLE_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;

#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
	if (!options.use_pam)
		spw = getspnam(pw->pw_name);
#ifdef HAS_SHADOW_EXPIRE
#define	DAY		(24L * 60 * 60) /* 1 day in seconds */
	if (!options.use_pam && spw != NULL) {
		int disabled = 0;
		time_t today;

		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) {
			logit("Account %.100s has expired", pw->pw_name);
			return 0;
		}
	}
#endif /* HAS_SHADOW_EXPIRE */
#endif /* defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) */

	/* grab passwd field for locked account check */
#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
	if (spw != NULL)
		passwd = spw->sp_pwdp;
#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 (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) {
		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 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) {
			logit("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) {
			logit("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();
				logit("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();
				logit("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)) {
		char *msg;

		if (loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &msg) != 0) {
			int loginrestrict_errno = errno;

			if (msg && *msg) {
				buffer_append(&loginmsg, msg, strlen(msg));
				aix_remove_embedded_newlines(msg);
				logit("Login restricted for %s: %.100s",
				    pw->pw_name, msg);
			}
			/* 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;
}

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

#ifdef CUSTOM_FAILED_LOGIN
	if (authenticated == 0 && strcmp(method, "password") == 0)
		record_failed_login(authctxt->user, "ssh");
#endif
}

/*
 * 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) {
			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_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)) {
			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;

	pw = getpwnam(user);
	if (pw == NULL) {
		logit("Illegal user %.100s from %.100s",
		    user, get_remote_ipaddr());
#ifdef CUSTOM_FAILED_LOGIN
		record_failed_login(user, "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;
	}
}

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 = -1;
	fake.pw_gid = -1;
#ifdef HAVE_PW_CLASS_IN_PASSWD
	fake.pw_class = "";
#endif
	fake.pw_dir = "/nonexist";
	fake.pw_shell = "/nonexist";

	return (&fake);
}
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"
aff51935	26	RCSID("$OpenBSD: auth.c,v 1.51 2003/11/21 11:57:02 djm 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;
bc7dfc06	57	extern Buffer loginmsg;
7368a6c8	58
01dafcb5	59	/* Debugging messages */
	60	Buffer auth_debug;
	61	int auth_debug_init;
	62
7368a6c8	63	/*
c6a69271	64	* Check if the user is allowed to log in via ssh. If user is listed
	65	* in DenyUsers or one of user's groups is listed in DenyGroups, false
	66	* will be returned. If AllowUsers isn't empty and user isn't listed
	67	* there, or if AllowGroups isn't empty and one of user's groups isn't
	68	* listed there, false will be returned.
7368a6c8	69	* If the user's shell is not executable, false will be returned.
6ae2364d	70	* Otherwise true is returned.
7368a6c8	71	*/
a306f2dd	72	int
7368a6c8	73	allowed_user(struct passwd * pw)
	74	{
	75	struct stat st;
da67ae18	76	const char hostname = NULL, ipaddr = NULL, *passwd = NULL;
614dee3a	77	char *shell;
7368a6c8	78	int i;
3e6e3da0	79	#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
3e6e3da0	80	struct spwd *spw = NULL;
e2ef2342	81	#endif
7368a6c8	82
7368a6c8	83	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
c6a69271	84	if (!pw \|\| !pw->pw_name)
7368a6c8	85	return 0;
7368a6c8	86
3e6e3da0	87	#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
	88	if (!options.use_pam)
	89	spw = getspnam(pw->pw_name);
	90	#ifdef HAS_SHADOW_EXPIRE
b57c8e20	91	#define DAY (24L * 60 * 60) /* 1 day in seconds */
3e6e3da0	92	if (!options.use_pam && spw != NULL) {
11d40248	93	int disabled = 0;
3e6e3da0	94	time_t today;
3e6e3da0	95
5ed5468f	96	today = time(NULL) / DAY;
	97	debug3("allowed_user: today %d sp_expire %d sp_lstchg %d"
	98	" sp_max %d", (int)today, (int)spw->sp_expire,
	99	(int)spw->sp_lstchg, (int)spw->sp_max);
b57c8e20	100
5ed5468f	101	/*
	102	* We assume account and password expiration occurs the
	103	* day after the day specified.
	104	*/
	105	if (spw->sp_expire != -1 && today > spw->sp_expire) {
bbe88b6d	106	logit("Account %.100s has expired", pw->pw_name);
5ed5468f	107	return 0;
5ed5468f	108	}
b57c8e20	109	}
3e6e3da0	110	#endif /* HAS_SHADOW_EXPIRE */
	111	#endif /* defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) */
	112
aff51935	113	/* grab passwd field for locked account check */
3e6e3da0	114	#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
	115	if (spw != NULL)
	116	passwd = spw->sp_pwdp;
	117	#else
	118	passwd = pw->pw_passwd;
b57c8e20	119	#endif
b57c8e20	120
aff51935	121	/* check for locked account */
da67ae18	122	if (!options.use_pam && passwd && *passwd) {
3e6e3da0	123	int locked = 0;
	124
	125	#ifdef LOCKED_PASSWD_STRING
	126	if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
	127	locked = 1;
	128	#endif
	129	#ifdef LOCKED_PASSWD_PREFIX
	130	if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
	131	strlen(LOCKED_PASSWD_PREFIX)) == 0)
	132	locked = 1;
	133	#endif
	134	#ifdef LOCKED_PASSWD_SUBSTR
	135	if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
	136	locked = 1;
	137	#endif
	138	if (locked) {
	139	logit("User %.100s not allowed because account is locked",
	140	pw->pw_name);
	141	return 0;
	142	}
	143	}
	144
301e9b01	145	/*
	146	* Get the shell from the password data. An empty shell field is
	147	* legal, and means /bin/sh.
	148	*/
	149	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
	150
	151	/* deny if shell does not exists or is not executable */
b334badd	152	if (stat(shell, &st) != 0) {
bbe88b6d	153	logit("User %.100s not allowed because shell %.100s does not exist",
b334badd	154	pw->pw_name, shell);
7368a6c8	155	return 0;
b334badd	156	}
c390a3c8	157	if (S_ISREG(st.st_mode) == 0 \|\|
c390a3c8	158	(st.st_mode & (S_IXOTH\|S_IXUSR\|S_IXGRP)) == 0) {
bbe88b6d	159	logit("User %.100s not allowed because shell %.100s is not executable",
b334badd	160	pw->pw_name, shell);
7368a6c8	161	return 0;
b334badd	162	}
7368a6c8	163
6805fc56	164	if (options.num_deny_users > 0 \|\| options.num_allow_users > 0) {
c5a7d788	165	hostname = get_canonical_hostname(options.use_dns);
6805fc56	166	ipaddr = get_remote_ipaddr();
	167	}
	168
7368a6c8	169	/* Return false if user is listed in DenyUsers */
7368a6c8	170	if (options.num_deny_users > 0) {
7368a6c8	171	for (i = 0; i < options.num_deny_users; i++)
762715ce	172	if (match_user(pw->pw_name, hostname, ipaddr,
b334badd	173	options.deny_users[i])) {
bbe88b6d	174	logit("User %.100s not allowed because listed in DenyUsers",
762715ce	175	pw->pw_name);
7368a6c8	176	return 0;
b334badd	177	}
7368a6c8	178	}
	179	/* Return false if AllowUsers isn't empty and user isn't listed there */
	180	if (options.num_allow_users > 0) {
7368a6c8	181	for (i = 0; i < options.num_allow_users; i++)
762715ce	182	if (match_user(pw->pw_name, hostname, ipaddr,
80f8f24f	183	options.allow_users[i]))
7368a6c8	184	break;
7368a6c8	185	/* i < options.num_allow_users iff we break for loop */
b334badd	186	if (i >= options.num_allow_users) {
bbe88b6d	187	logit("User %.100s not allowed because not listed in AllowUsers",
b334badd	188	pw->pw_name);
7368a6c8	189	return 0;
b334badd	190	}
7368a6c8	191	}
7368a6c8	192	if (options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
c6a69271	193	/* Get the user's group access list (primary and supplementary) */
b334badd	194	if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
bbe88b6d	195	logit("User %.100s not allowed because not in any group",
b334badd	196	pw->pw_name);
7368a6c8	197	return 0;
b334badd	198	}
7368a6c8	199
c6a69271	200	/* Return false if one of user's groups is listed in DenyGroups */
	201	if (options.num_deny_groups > 0)
	202	if (ga_match(options.deny_groups,
	203	options.num_deny_groups)) {
	204	ga_free();
bbe88b6d	205	logit("User %.100s not allowed because a group is listed in DenyGroups",
b334badd	206	pw->pw_name);
7368a6c8	207	return 0;
c6a69271	208	}
7368a6c8	209	/*
c6a69271	210	* Return false if AllowGroups isn't empty and one of user's groups
7368a6c8	211	* isn't listed there
7368a6c8	212	*/
c6a69271	213	if (options.num_allow_groups > 0)
	214	if (!ga_match(options.allow_groups,
	215	options.num_allow_groups)) {
	216	ga_free();
bbe88b6d	217	logit("User %.100s not allowed because none of user's groups are listed in AllowGroups",
b334badd	218	pw->pw_name);
7368a6c8	219	return 0;
c6a69271	220	}
c6a69271	221	ga_free();
7368a6c8	222	}
	223
	224	#ifdef WITH_AIXAUTHENTICATE
f3e87063	225	/*
	226	* Don't check loginrestrictions() for root account (use
	227	* PermitRootLogin to control logins via ssh), or if running as
	228	* non-root user (since loginrestrictions will always fail).
	229	*/
bc7dfc06	230	if ((pw->pw_uid != 0) && (geteuid() == 0)) {
	231	char *msg;
	232
aff51935	233	if (loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &msg) != 0) {
bc7dfc06	234	int loginrestrict_errno = errno;
	235
	236	if (msg && *msg) {
	237	buffer_append(&loginmsg, msg, strlen(msg));
	238	aix_remove_embedded_newlines(msg);
	239	logit("Login restricted for %s: %.100s",
	240	pw->pw_name, msg);
5daf7064	241	}
bc7dfc06	242	/* Don't fail if /etc/nologin set */
aff51935	243	if (!(loginrestrict_errno == EPERM &&
bc7dfc06	244	stat(_PATH_NOLOGIN, &st) == 0))
bc7dfc06	245	return 0;
c1ef8333	246	}
c1ef8333	247	}
7368a6c8	248	#endif /* WITH_AIXAUTHENTICATE */
	249
	250	/* We found no reason not to let this user try to log on... */
	251	return 1;
	252	}
59c97189	253
59c97189	254	void
	255	auth_log(Authctxt authctxt, int authenticated, char method, char *info)
	256	{
	257	void (authlog) (const char fmt,...) = verbose;
	258	char *authmsg;
	259
	260	/* Raise logging level */
	261	if (authenticated == 1 \|\|
	262	!authctxt->valid \|\|
	263	authctxt->failures >= AUTH_FAIL_LOG \|\|
	264	strcmp(method, "password") == 0)
a3568201	265	authlog = logit;
59c97189	266
	267	if (authctxt->postponed)
	268	authmsg = "Postponed";
	269	else
	270	authmsg = authenticated ? "Accepted" : "Failed";
	271
	272	authlog("%s %s for %s%.100s from %.200s port %d%s",
	273	authmsg,
	274	method,
	275	authctxt->valid ? "" : "illegal user ",
fad3754c	276	authctxt->user,
59c97189	277	get_remote_ipaddr(),
	278	get_remote_port(),
	279	info);
56fd97d7	280
73d9dad3	281	#ifdef CUSTOM_FAILED_LOGIN
56fd97d7	282	if (authenticated == 0 && strcmp(method, "password") == 0)
73d9dad3	283	record_failed_login(authctxt->user, "ssh");
73d9dad3	284	#endif
59c97189	285	}
	286
	287	/*
15853e93	288	* Check whether root logins are disallowed.
59c97189	289	*/
59c97189	290	int
15853e93	291	auth_root_allowed(char *method)
59c97189	292	{
15853e93	293	switch (options.permit_root_login) {
15853e93	294	case PERMIT_YES:
59c97189	295	return 1;
15853e93	296	break;
	297	case PERMIT_NO_PASSWD:
	298	if (strcmp(method, "password") != 0)
	299	return 1;
	300	break;
	301	case PERMIT_FORCED_ONLY:
	302	if (forced_command) {
bbe88b6d	303	logit("Root login accepted for forced command.");
15853e93	304	return 1;
	305	}
	306	break;
59c97189	307	}
bbe88b6d	308	logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
15853e93	309	return 0;
59c97189	310	}
c8445989	311
	312
	313	/*
	314	* Given a template and a passwd structure, build a filename
	315	* by substituting % tokenised options. Currently, %% becomes '%',
	316	* %h becomes the home directory and %u the username.
	317	*
	318	* This returns a buffer allocated by xmalloc.
	319	*/
	320	char *
	321	expand_filename(const char filename, struct passwd pw)
	322	{
	323	Buffer buffer;
	324	char *file;
	325	const char *cp;
	326
	327	/*
	328	* Build the filename string in the buffer by making the appropriate
	329	* substitutions to the given file name.
	330	*/
	331	buffer_init(&buffer);
	332	for (cp = filename; *cp; cp++) {
	333	if (cp[0] == '%' && cp[1] == '%') {
	334	buffer_append(&buffer, "%", 1);
	335	cp++;
	336	continue;
	337	}
	338	if (cp[0] == '%' && cp[1] == 'h') {
	339	buffer_append(&buffer, pw->pw_dir, strlen(pw->pw_dir));
	340	cp++;
	341	continue;
	342	}
	343	if (cp[0] == '%' && cp[1] == 'u') {
	344	buffer_append(&buffer, pw->pw_name,
184eed6a	345	strlen(pw->pw_name));
c8445989	346	cp++;
	347	continue;
	348	}
	349	buffer_append(&buffer, cp, 1);
	350	}
	351	buffer_append(&buffer, "\0", 1);
	352
	353	/*
	354	* Ensure that filename starts anchored. If not, be backward
	355	* compatible and prepend the '%h/'
	356	*/
	357	file = xmalloc(MAXPATHLEN);
	358	cp = buffer_ptr(&buffer);
	359	if (*cp != '/')
	360	snprintf(file, MAXPATHLEN, "%s/%s", pw->pw_dir, cp);
	361	else
	362	strlcpy(file, cp, MAXPATHLEN);
	363
	364	buffer_free(&buffer);
	365	return file;
	366	}
	367
	368	char *
	369	authorized_keys_file(struct passwd *pw)
	370	{
	371	return expand_filename(options.authorized_keys_file, pw);
	372	}
	373
	374	char *
	375	authorized_keys_file2(struct passwd *pw)
	376	{
	377	return expand_filename(options.authorized_keys_file2, pw);
	378	}
	379
d0c8ca5c	380	/* return ok if key exists in sysfile or userfile */
	381	HostStatus
	382	check_key_in_hostfiles(struct passwd pw, Key key, const char *host,
	383	const char sysfile, const char userfile)
	384	{
	385	Key *found;
	386	char *user_hostfile;
	387	struct stat st;
17a3011c	388	HostStatus host_status;
d0c8ca5c	389
	390	/* Check if we know the host and its host key. */
	391	found = key_new(key->type);
	392	host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
	393
	394	if (host_status != HOST_OK && userfile != NULL) {
	395	user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
	396	if (options.strict_modes &&
	397	(stat(user_hostfile, &st) == 0) &&
	398	((st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
184eed6a	399	(st.st_mode & 022) != 0)) {
bbe88b6d	400	logit("Authentication refused for %.100s: "
d0c8ca5c	401	"bad owner or modes for %.200s",
	402	pw->pw_name, user_hostfile);
	403	} else {
	404	temporarily_use_uid(pw);
	405	host_status = check_host_in_hostfile(user_hostfile,
	406	host, key, found, NULL);
	407	restore_uid();
	408	}
	409	xfree(user_hostfile);
	410	}
	411	key_free(found);
	412
	413	debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
	414	"ok" : "not found", host);
	415	return host_status;
	416	}
	417
	418
c8445989	419	/*
c8445989	420	* Check a given file for security. This is defined as all components
d6097023	421	* of the path to the file must be owned by either the owner of
1ddf764b	422	* of the file or root and no directories must be group or world writable.
c8445989	423	*
	424	* XXX Should any specific check be done for sym links ?
	425	*
	426	* Takes an open file descriptor, the file name, a uid and and
	427	* error buffer plus max size as arguments.
	428	*
	429	* Returns 0 on success and -1 on failure
	430	*/
	431	int
6978866a	432	secure_filename(FILE f, const char file, struct passwd *pw,
6978866a	433	char *err, size_t errlen)
c8445989	434	{
6978866a	435	uid_t uid = pw->pw_uid;
76fbdd47	436	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
c8445989	437	char *cp;
f6f02456	438	int comparehome = 0;
c8445989	439	struct stat st;
	440
	441	if (realpath(file, buf) == NULL) {
	442	snprintf(err, errlen, "realpath %s failed: %s", file,
	443	strerror(errno));
	444	return -1;
	445	}
f6f02456	446	if (realpath(pw->pw_dir, homedir) != NULL)
f6f02456	447	comparehome = 1;
c8445989	448
	449	/* check the open file to avoid races */
	450	if (fstat(fileno(f), &st) < 0 \|\|
	451	(st.st_uid != 0 && st.st_uid != uid) \|\|
	452	(st.st_mode & 022) != 0) {
	453	snprintf(err, errlen, "bad ownership or modes for file %s",
	454	buf);
	455	return -1;
	456	}
	457
	458	/* for each component of the canonical path, walking upwards */
	459	for (;;) {
	460	if ((cp = dirname(buf)) == NULL) {
	461	snprintf(err, errlen, "dirname() failed");
	462	return -1;
	463	}
	464	strlcpy(buf, cp, sizeof(buf));
	465
	466	debug3("secure_filename: checking '%s'", buf);
	467	if (stat(buf, &st) < 0 \|\|
	468	(st.st_uid != 0 && st.st_uid != uid) \|\|
	469	(st.st_mode & 022) != 0) {
184eed6a	470	snprintf(err, errlen,
c8445989	471	"bad ownership or modes for directory %s", buf);
	472	return -1;
	473	}
	474
afd501f9	475	/* If are passed the homedir then we can stop */
f6f02456	476	if (comparehome && strcmp(homedir, buf) == 0) {
afd501f9	477	debug3("secure_filename: terminating check at '%s'",
	478	buf);
	479	break;
	480	}
c8445989	481	/*
	482	* dirname should always complete with a "/" path,
	483	* but we can be paranoid and check for "." too
	484	*/
	485	if ((strcmp("/", buf) == 0) \|\| (strcmp(".", buf) == 0))
	486	break;
	487	}
	488	return 0;
	489	}
443fa1cd	490
	491	struct passwd *
	492	getpwnamallow(const char *user)
	493	{
1836f69f	494	#ifdef HAVE_LOGIN_CAP
	495	extern login_cap_t *lc;
	496	#ifdef BSD_AUTH
	497	auth_session_t *as;
	498	#endif
	499	#endif
443fa1cd	500	struct passwd *pw;
	501
	502	pw = getpwnam(user);
c2802d92	503	if (pw == NULL) {
bbe88b6d	504	logit("Illegal user %.100s from %.100s",
c2802d92	505	user, get_remote_ipaddr());
73d9dad3	506	#ifdef CUSTOM_FAILED_LOGIN
73d9dad3	507	record_failed_login(user, "ssh");
819d3f09	508	#endif
c2802d92	509	return (NULL);
	510	}
	511	if (!allowed_user(pw))
1836f69f	512	return (NULL);
	513	#ifdef HAVE_LOGIN_CAP
	514	if ((lc = login_getclass(pw->pw_class)) == NULL) {
	515	debug("unable to get login class: %s", user);
	516	return (NULL);
	517	}
	518	#ifdef BSD_AUTH
	519	if ((as = auth_open()) == NULL \|\| auth_setpwd(as, pw) != 0 \|\|
65721f9c	520	auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
1836f69f	521	debug("Approval failure for %s", user);
443fa1cd	522	pw = NULL;
1836f69f	523	}
	524	if (as != NULL)
	525	auth_close(as);
	526	#endif
	527	#endif
06bea668	528	if (pw != NULL)
	529	return (pwcopy(pw));
	530	return (NULL);
443fa1cd	531	}
01dafcb5	532
	533	void
	534	auth_debug_add(const char *fmt,...)
	535	{
	536	char buf[1024];
	537	va_list args;
	538
	539	if (!auth_debug_init)
	540	return;
	541
	542	va_start(args, fmt);
	543	vsnprintf(buf, sizeof(buf), fmt, args);
	544	va_end(args);
	545	buffer_put_cstring(&auth_debug, buf);
	546	}
	547
	548	void
	549	auth_debug_send(void)
	550	{
	551	char *msg;
	552
	553	if (!auth_debug_init)
	554	return;
	555	while (buffer_len(&auth_debug)) {
	556	msg = buffer_get_string(&auth_debug, NULL);
	557	packet_send_debug("%s", msg);
	558	xfree(msg);
	559	}
	560	}
	561
	562	void
	563	auth_debug_reset(void)
	564	{
	565	if (auth_debug_init)
	566	buffer_clear(&auth_debug);
	567	else {
	568	buffer_init(&auth_debug);
	569	auth_debug_init = 1;
	570	}
	571	}
96d0bf74	572
	573	struct passwd *
	574	fakepw(void)
	575	{
	576	static struct passwd fake;
	577
	578	memset(&fake, 0, sizeof(fake));
	579	fake.pw_name = "NOUSER";
	580	fake.pw_passwd =
b6453d99	581	"$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
96d0bf74	582	fake.pw_gecos = "NOUSER";
	583	fake.pw_uid = -1;
	584	fake.pw_gid = -1;
	585	#ifdef HAVE_PW_CLASS_IN_PASSWD
	586	fake.pw_class = "";
	587	#endif
	588	fake.pw_dir = "/nonexist";
	589	fake.pw_shell = "/nonexist";
	590
	591	return (&fake);
	592	}