[openssh.git] / auth.c

/* $OpenBSD: auth.c,v 1.72 2006/07/22 20:48:22 stevesk 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 <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 <string.h>

#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 "misc.h"
#include "bufaux.h"
#include "packet.h"
#include "loginrec.h"
#include "monitor_wrap.h"

/* import */
extern ServerOptions options;
extern int use_privsep;
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;
	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,
	    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");
#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.
 */
static 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, 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 = (uid_t)-1;
	fake.pw_gid = (gid_t)-1;
#ifdef HAVE_PW_CLASS_IN_PASSWD
	fake.pw_class = "";
#endif
	fake.pw_dir = "/nonexist";
	fake.pw_shell = "/nonexist";

	return (&fake);
}
Commit	Line	Data
00146caa	1	/* $OpenBSD: auth.c,v 1.72 2006/07/22 20:48:22 stevesk Exp $ */
20d0f77f	2	/*
f3c7c613	3	* Copyright (c) 2000 Markus Friedl. All rights reserved.
bcbf86ec	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.
7368a6c8	24	*/
	25
	26	#include "includes.h"
4095f623	27
	28	#include <sys/types.h>
	29	#include <sys/stat.h>
7368a6c8	30
028094f4	31	#include <errno.h>
a75f5360	32	#ifdef HAVE_PATHS_H
6f61e0ec	33	# include <paths.h>
a75f5360	34	#endif
b1842393	35	#include <pwd.h>
c1ef8333	36	#ifdef HAVE_LOGIN_H
	37	#include <login.h>
	38	#endif
f14ca4a4	39	#ifdef USE_SHADOW
4cb5ffa0	40	#include <shadow.h>
f14ca4a4	41	#endif
b4d02860	42	#ifdef HAVE_LIBGEN_H
c8445989	43	#include <libgen.h>
b4d02860	44	#endif
4c72fcfd	45	#include <stdarg.h>
00146caa	46	#include <string.h>
c8445989	47
42f11eb2	48	#include "xmalloc.h"
	49	#include "match.h"
	50	#include "groupaccess.h"
	51	#include "log.h"
	52	#include "servconf.h"
e78a59f5	53	#include "auth.h"
59c97189	54	#include "auth-options.h"
42f11eb2	55	#include "canohost.h"
c8445989	56	#include "buffer.h"
c8445989	57	#include "bufaux.h"
d0c8ca5c	58	#include "uidswap.h"
5f1f36b5	59	#include "misc.h"
01dafcb5	60	#include "bufaux.h"
01dafcb5	61	#include "packet.h"
575e336f	62	#include "loginrec.h"
c00e4d75	63	#include "monitor_wrap.h"
e78a59f5	64
7368a6c8	65	/* import */
7368a6c8	66	extern ServerOptions options;
c023a130	67	extern int use_privsep;
bc7dfc06	68	extern Buffer loginmsg;
7368a6c8	69
01dafcb5	70	/* Debugging messages */
	71	Buffer auth_debug;
	72	int auth_debug_init;
	73
7368a6c8	74	/*
c6a69271	75	* Check if the user is allowed to log in via ssh. If user is listed
	76	* in DenyUsers or one of user's groups is listed in DenyGroups, false
	77	* will be returned. If AllowUsers isn't empty and user isn't listed
	78	* there, or if AllowGroups isn't empty and one of user's groups isn't
	79	* listed there, false will be returned.
7368a6c8	80	* If the user's shell is not executable, false will be returned.
6ae2364d	81	* Otherwise true is returned.
7368a6c8	82	*/
a306f2dd	83	int
7368a6c8	84	allowed_user(struct passwd * pw)
	85	{
	86	struct stat st;
da67ae18	87	const char hostname = NULL, ipaddr = NULL, *passwd = NULL;
614dee3a	88	char *shell;
2ceb8101	89	u_int i;
f14ca4a4	90	#ifdef USE_SHADOW
3e6e3da0	91	struct spwd *spw = NULL;
e2ef2342	92	#endif
7368a6c8	93
7368a6c8	94	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
c6a69271	95	if (!pw \|\| !pw->pw_name)
7368a6c8	96	return 0;
7368a6c8	97
f14ca4a4	98	#ifdef USE_SHADOW
3e6e3da0	99	if (!options.use_pam)
	100	spw = getspnam(pw->pw_name);
	101	#ifdef HAS_SHADOW_EXPIRE
f14ca4a4	102	if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
f14ca4a4	103	return 0;
3e6e3da0	104	#endif /* HAS_SHADOW_EXPIRE */
f14ca4a4	105	#endif /* USE_SHADOW */
3e6e3da0	106
aff51935	107	/* grab passwd field for locked account check */
f14ca4a4	108	#ifdef USE_SHADOW
3e6e3da0	109	if (spw != NULL)
26d07095	110	#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
4c653d8e	111	passwd = get_iaf_password(pw);
4c653d8e	112	#else
3e6e3da0	113	passwd = spw->sp_pwdp;
26d07095	114	#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
3e6e3da0	115	#else
3e6e3da0	116	passwd = pw->pw_passwd;
b57c8e20	117	#endif
b57c8e20	118
aff51935	119	/* check for locked account */
da67ae18	120	if (!options.use_pam && passwd && *passwd) {
3e6e3da0	121	int locked = 0;
	122
	123	#ifdef LOCKED_PASSWD_STRING
	124	if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
	125	locked = 1;
	126	#endif
	127	#ifdef LOCKED_PASSWD_PREFIX
	128	if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
	129	strlen(LOCKED_PASSWD_PREFIX)) == 0)
	130	locked = 1;
	131	#endif
	132	#ifdef LOCKED_PASSWD_SUBSTR
	133	if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
	134	locked = 1;
	135	#endif
26d07095	136	#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
	137	free(passwd);
	138	#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
3e6e3da0	139	if (locked) {
	140	logit("User %.100s not allowed because account is locked",
	141	pw->pw_name);
	142	return 0;
	143	}
	144	}
	145
301e9b01	146	/*
	147	* Get the shell from the password data. An empty shell field is
	148	* legal, and means /bin/sh.
	149	*/
	150	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
	151
	152	/* deny if shell does not exists or is not executable */
b334badd	153	if (stat(shell, &st) != 0) {
bbe88b6d	154	logit("User %.100s not allowed because shell %.100s does not exist",
b334badd	155	pw->pw_name, shell);
7368a6c8	156	return 0;
b334badd	157	}
c390a3c8	158	if (S_ISREG(st.st_mode) == 0 \|\|
c390a3c8	159	(st.st_mode & (S_IXOTH\|S_IXUSR\|S_IXGRP)) == 0) {
bbe88b6d	160	logit("User %.100s not allowed because shell %.100s is not executable",
b334badd	161	pw->pw_name, shell);
7368a6c8	162	return 0;
b334badd	163	}
7368a6c8	164
2dcbac07	165	if (options.num_deny_users > 0 \|\| options.num_allow_users > 0 \|\|
2dcbac07	166	options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
c5a7d788	167	hostname = get_canonical_hostname(options.use_dns);
6805fc56	168	ipaddr = get_remote_ipaddr();
	169	}
	170
7368a6c8	171	/* Return false if user is listed in DenyUsers */
7368a6c8	172	if (options.num_deny_users > 0) {
7368a6c8	173	for (i = 0; i < options.num_deny_users; i++)
762715ce	174	if (match_user(pw->pw_name, hostname, ipaddr,
b334badd	175	options.deny_users[i])) {
31de8b2b	176	logit("User %.100s from %.100s not allowed "
	177	"because listed in DenyUsers",
	178	pw->pw_name, hostname);
7368a6c8	179	return 0;
b334badd	180	}
7368a6c8	181	}
	182	/* Return false if AllowUsers isn't empty and user isn't listed there */
	183	if (options.num_allow_users > 0) {
7368a6c8	184	for (i = 0; i < options.num_allow_users; i++)
762715ce	185	if (match_user(pw->pw_name, hostname, ipaddr,
80f8f24f	186	options.allow_users[i]))
7368a6c8	187	break;
7368a6c8	188	/* i < options.num_allow_users iff we break for loop */
b334badd	189	if (i >= options.num_allow_users) {
31de8b2b	190	logit("User %.100s from %.100s not allowed because "
31de8b2b	191	"not listed in AllowUsers", pw->pw_name, hostname);
7368a6c8	192	return 0;
b334badd	193	}
7368a6c8	194	}
7368a6c8	195	if (options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
c6a69271	196	/* Get the user's group access list (primary and supplementary) */
b334badd	197	if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
31de8b2b	198	logit("User %.100s from %.100s not allowed because "
31de8b2b	199	"not in any group", pw->pw_name, hostname);
7368a6c8	200	return 0;
b334badd	201	}
7368a6c8	202
c6a69271	203	/* Return false if one of user's groups is listed in DenyGroups */
	204	if (options.num_deny_groups > 0)
	205	if (ga_match(options.deny_groups,
	206	options.num_deny_groups)) {
	207	ga_free();
31de8b2b	208	logit("User %.100s from %.100s not allowed "
	209	"because a group is listed in DenyGroups",
	210	pw->pw_name, hostname);
7368a6c8	211	return 0;
c6a69271	212	}
7368a6c8	213	/*
c6a69271	214	* Return false if AllowGroups isn't empty and one of user's groups
7368a6c8	215	* isn't listed there
7368a6c8	216	*/
c6a69271	217	if (options.num_allow_groups > 0)
	218	if (!ga_match(options.allow_groups,
	219	options.num_allow_groups)) {
	220	ga_free();
31de8b2b	221	logit("User %.100s from %.100s not allowed "
	222	"because none of user's groups are listed "
	223	"in AllowGroups", pw->pw_name, hostname);
7368a6c8	224	return 0;
c6a69271	225	}
c6a69271	226	ga_free();
7368a6c8	227	}
7368a6c8	228
bc5c2025	229	#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
5ccf88cb	230	if (!sys_auth_allowed_user(pw, &loginmsg))
bc5c2025	231	return 0;
bc5c2025	232	#endif
7368a6c8	233
	234	/* We found no reason not to let this user try to log on... */
	235	return 1;
	236	}
59c97189	237
59c97189	238	void
	239	auth_log(Authctxt authctxt, int authenticated, char method, char *info)
	240	{
	241	void (authlog) (const char fmt,...) = verbose;
	242	char *authmsg;
	243
c023a130	244	if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
	245	return;
	246
59c97189	247	/* Raise logging level */
	248	if (authenticated == 1 \|\|
	249	!authctxt->valid \|\|
af4bd935	250	authctxt->failures >= options.max_authtries / 2 \|\|
59c97189	251	strcmp(method, "password") == 0)
a3568201	252	authlog = logit;
59c97189	253
	254	if (authctxt->postponed)
	255	authmsg = "Postponed";
	256	else
	257	authmsg = authenticated ? "Accepted" : "Failed";
	258
	259	authlog("%s %s for %s%.100s from %.200s port %d%s",
	260	authmsg,
	261	method,
d77347cc	262	authctxt->valid ? "" : "invalid user ",
fad3754c	263	authctxt->user,
59c97189	264	get_remote_ipaddr(),
	265	get_remote_port(),
	266	info);
56fd97d7	267
73d9dad3	268	#ifdef CUSTOM_FAILED_LOGIN
b6610e8f	269	if (authenticated == 0 && !authctxt->postponed &&
b6610e8f	270	(strcmp(method, "password") == 0 \|\|
6af6e631	271	strncmp(method, "keyboard-interactive", 20) == 0 \|\|
6af6e631	272	strcmp(method, "challenge-response") == 0))
575e336f	273	record_failed_login(authctxt->user,
575e336f	274	get_canonical_hostname(options.use_dns), "ssh");
73d9dad3	275	#endif
6039eeef	276	#ifdef SSH_AUDIT_EVENTS
2ae7f715	277	if (authenticated == 0 && !authctxt->postponed)
2ae7f715	278	audit_event(audit_classify_auth(method));
c00e4d75	279	#endif
59c97189	280	}
	281
	282	/*
15853e93	283	* Check whether root logins are disallowed.
59c97189	284	*/
59c97189	285	int
15853e93	286	auth_root_allowed(char *method)
59c97189	287	{
15853e93	288	switch (options.permit_root_login) {
15853e93	289	case PERMIT_YES:
59c97189	290	return 1;
15853e93	291	case PERMIT_NO_PASSWD:
	292	if (strcmp(method, "password") != 0)
	293	return 1;
	294	break;
	295	case PERMIT_FORCED_ONLY:
	296	if (forced_command) {
bbe88b6d	297	logit("Root login accepted for forced command.");
15853e93	298	return 1;
	299	}
	300	break;
59c97189	301	}
bbe88b6d	302	logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
15853e93	303	return 0;
59c97189	304	}
c8445989	305
	306
	307	/*
	308	* Given a template and a passwd structure, build a filename
	309	* by substituting % tokenised options. Currently, %% becomes '%',
	310	* %h becomes the home directory and %u the username.
	311	*
	312	* This returns a buffer allocated by xmalloc.
	313	*/
a980cbd7	314	static char *
a980cbd7	315	expand_authorized_keys(const char filename, struct passwd pw)
c8445989	316	{
52e3daed	317	char *file, ret[MAXPATHLEN];
52e3daed	318	int i;
c8445989	319
a980cbd7	320	file = percent_expand(filename, "h", pw->pw_dir,
a980cbd7	321	"u", pw->pw_name, (char *)NULL);
c8445989	322
	323	/*
	324	* Ensure that filename starts anchored. If not, be backward
	325	* compatible and prepend the '%h/'
	326	*/
a980cbd7	327	if (*file == '/')
	328	return (file);
	329
52e3daed	330	i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
52e3daed	331	if (i < 0 \|\| (size_t)i >= sizeof(ret))
a980cbd7	332	fatal("expand_authorized_keys: path too long");
a980cbd7	333	xfree(file);
52e3daed	334	return (xstrdup(ret));
c8445989	335	}
	336
	337	char *
	338	authorized_keys_file(struct passwd *pw)
	339	{
a980cbd7	340	return expand_authorized_keys(options.authorized_keys_file, pw);
c8445989	341	}
	342
	343	char *
	344	authorized_keys_file2(struct passwd *pw)
	345	{
a980cbd7	346	return expand_authorized_keys(options.authorized_keys_file2, pw);
c8445989	347	}
c8445989	348
d0c8ca5c	349	/* return ok if key exists in sysfile or userfile */
	350	HostStatus
	351	check_key_in_hostfiles(struct passwd pw, Key key, const char *host,
	352	const char sysfile, const char userfile)
	353	{
	354	Key *found;
	355	char *user_hostfile;
	356	struct stat st;
17a3011c	357	HostStatus host_status;
d0c8ca5c	358
	359	/* Check if we know the host and its host key. */
	360	found = key_new(key->type);
	361	host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
	362
	363	if (host_status != HOST_OK && userfile != NULL) {
	364	user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
	365	if (options.strict_modes &&
	366	(stat(user_hostfile, &st) == 0) &&
	367	((st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
184eed6a	368	(st.st_mode & 022) != 0)) {
bbe88b6d	369	logit("Authentication refused for %.100s: "
d0c8ca5c	370	"bad owner or modes for %.200s",
	371	pw->pw_name, user_hostfile);
	372	} else {
	373	temporarily_use_uid(pw);
	374	host_status = check_host_in_hostfile(user_hostfile,
	375	host, key, found, NULL);
	376	restore_uid();
	377	}
	378	xfree(user_hostfile);
	379	}
	380	key_free(found);
	381
	382	debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
	383	"ok" : "not found", host);
	384	return host_status;
	385	}
	386
	387
c8445989	388	/*
c8445989	389	* Check a given file for security. This is defined as all components
d6097023	390	* of the path to the file must be owned by either the owner of
1ddf764b	391	* of the file or root and no directories must be group or world writable.
c8445989	392	*
	393	* XXX Should any specific check be done for sym links ?
	394	*
	395	* Takes an open file descriptor, the file name, a uid and and
	396	* error buffer plus max size as arguments.
	397	*
	398	* Returns 0 on success and -1 on failure
	399	*/
	400	int
6978866a	401	secure_filename(FILE f, const char file, struct passwd *pw,
6978866a	402	char *err, size_t errlen)
c8445989	403	{
6978866a	404	uid_t uid = pw->pw_uid;
76fbdd47	405	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
c8445989	406	char *cp;
f6f02456	407	int comparehome = 0;
c8445989	408	struct stat st;
	409
	410	if (realpath(file, buf) == NULL) {
	411	snprintf(err, errlen, "realpath %s failed: %s", file,
	412	strerror(errno));
	413	return -1;
	414	}
f6f02456	415	if (realpath(pw->pw_dir, homedir) != NULL)
f6f02456	416	comparehome = 1;
c8445989	417
	418	/* check the open file to avoid races */
	419	if (fstat(fileno(f), &st) < 0 \|\|
	420	(st.st_uid != 0 && st.st_uid != uid) \|\|
	421	(st.st_mode & 022) != 0) {
	422	snprintf(err, errlen, "bad ownership or modes for file %s",
	423	buf);
	424	return -1;
	425	}
	426
	427	/* for each component of the canonical path, walking upwards */
	428	for (;;) {
	429	if ((cp = dirname(buf)) == NULL) {
	430	snprintf(err, errlen, "dirname() failed");
	431	return -1;
	432	}
	433	strlcpy(buf, cp, sizeof(buf));
	434
	435	debug3("secure_filename: checking '%s'", buf);
	436	if (stat(buf, &st) < 0 \|\|
	437	(st.st_uid != 0 && st.st_uid != uid) \|\|
	438	(st.st_mode & 022) != 0) {
184eed6a	439	snprintf(err, errlen,
c8445989	440	"bad ownership or modes for directory %s", buf);
	441	return -1;
	442	}
	443
afd501f9	444	/* If are passed the homedir then we can stop */
f6f02456	445	if (comparehome && strcmp(homedir, buf) == 0) {
afd501f9	446	debug3("secure_filename: terminating check at '%s'",
	447	buf);
	448	break;
	449	}
c8445989	450	/*
	451	* dirname should always complete with a "/" path,
	452	* but we can be paranoid and check for "." too
	453	*/
	454	if ((strcmp("/", buf) == 0) \|\| (strcmp(".", buf) == 0))
	455	break;
	456	}
	457	return 0;
	458	}
443fa1cd	459
	460	struct passwd *
	461	getpwnamallow(const char *user)
	462	{
1836f69f	463	#ifdef HAVE_LOGIN_CAP
	464	extern login_cap_t *lc;
	465	#ifdef BSD_AUTH
	466	auth_session_t *as;
	467	#endif
	468	#endif
443fa1cd	469	struct passwd *pw;
443fa1cd	470
d231781a	471	parse_server_match_config(&options, user,
	472	get_canonical_hostname(options.use_dns), get_remote_ipaddr());
	473
443fa1cd	474	pw = getpwnam(user);
c2802d92	475	if (pw == NULL) {
227a6a97	476	logit("Invalid user %.100s from %.100s",
c2802d92	477	user, get_remote_ipaddr());
73d9dad3	478	#ifdef CUSTOM_FAILED_LOGIN
575e336f	479	record_failed_login(user,
575e336f	480	get_canonical_hostname(options.use_dns), "ssh");
819d3f09	481	#endif
6039eeef	482	#ifdef SSH_AUDIT_EVENTS
	483	audit_event(SSH_INVALID_USER);
	484	#endif /* SSH_AUDIT_EVENTS */
c2802d92	485	return (NULL);
	486	}
	487	if (!allowed_user(pw))
1836f69f	488	return (NULL);
	489	#ifdef HAVE_LOGIN_CAP
	490	if ((lc = login_getclass(pw->pw_class)) == NULL) {
	491	debug("unable to get login class: %s", user);
	492	return (NULL);
	493	}
	494	#ifdef BSD_AUTH
	495	if ((as = auth_open()) == NULL \|\| auth_setpwd(as, pw) != 0 \|\|
65721f9c	496	auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
1836f69f	497	debug("Approval failure for %s", user);
443fa1cd	498	pw = NULL;
1836f69f	499	}
	500	if (as != NULL)
	501	auth_close(as);
	502	#endif
	503	#endif
06bea668	504	if (pw != NULL)
	505	return (pwcopy(pw));
	506	return (NULL);
443fa1cd	507	}
01dafcb5	508
	509	void
	510	auth_debug_add(const char *fmt,...)
	511	{
	512	char buf[1024];
	513	va_list args;
	514
	515	if (!auth_debug_init)
	516	return;
	517
	518	va_start(args, fmt);
	519	vsnprintf(buf, sizeof(buf), fmt, args);
	520	va_end(args);
	521	buffer_put_cstring(&auth_debug, buf);
	522	}
	523
	524	void
	525	auth_debug_send(void)
	526	{
	527	char *msg;
	528
	529	if (!auth_debug_init)
	530	return;
	531	while (buffer_len(&auth_debug)) {
	532	msg = buffer_get_string(&auth_debug, NULL);
	533	packet_send_debug("%s", msg);
	534	xfree(msg);
	535	}
	536	}
	537
	538	void
	539	auth_debug_reset(void)
	540	{
	541	if (auth_debug_init)
	542	buffer_clear(&auth_debug);
	543	else {
	544	buffer_init(&auth_debug);
	545	auth_debug_init = 1;
	546	}
	547	}
96d0bf74	548
	549	struct passwd *
	550	fakepw(void)
	551	{
	552	static struct passwd fake;
	553
	554	memset(&fake, 0, sizeof(fake));
	555	fake.pw_name = "NOUSER";
	556	fake.pw_passwd =
b6453d99	557	"$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
96d0bf74	558	fake.pw_gecos = "NOUSER";
f6be21a0	559	fake.pw_uid = (uid_t)-1;
f6be21a0	560	fake.pw_gid = (gid_t)-1;
96d0bf74	561	#ifdef HAVE_PW_CLASS_IN_PASSWD
	562	fake.pw_class = "";
	563	#endif
	564	fake.pw_dir = "/nonexist";
	565	fake.pw_shell = "/nonexist";
	566
	567	return (&fake);
	568	}