[openssh.git] / auth.c

/* $OpenBSD: auth.c,v 1.68 2006/07/06 16:03:53 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>

#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 "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;

	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
b1842393	1	/* $OpenBSD: auth.c,v 1.68 2006/07/06 16:03:53 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
a75f5360	31	#ifdef HAVE_PATHS_H
6f61e0ec	32	# include <paths.h>
a75f5360	33	#endif
b1842393	34	#include <pwd.h>
c1ef8333	35	#ifdef HAVE_LOGIN_H
	36	#include <login.h>
	37	#endif
f14ca4a4	38	#ifdef USE_SHADOW
4cb5ffa0	39	#include <shadow.h>
f14ca4a4	40	#endif
7368a6c8	41
b4d02860	42	#ifdef HAVE_LIBGEN_H
c8445989	43	#include <libgen.h>
b4d02860	44	#endif
c8445989	45
42f11eb2	46	#include "xmalloc.h"
	47	#include "match.h"
	48	#include "groupaccess.h"
	49	#include "log.h"
	50	#include "servconf.h"
e78a59f5	51	#include "auth.h"
59c97189	52	#include "auth-options.h"
42f11eb2	53	#include "canohost.h"
c8445989	54	#include "buffer.h"
c8445989	55	#include "bufaux.h"
d0c8ca5c	56	#include "uidswap.h"
5f1f36b5	57	#include "misc.h"
01dafcb5	58	#include "bufaux.h"
01dafcb5	59	#include "packet.h"
575e336f	60	#include "loginrec.h"
c00e4d75	61	#include "monitor_wrap.h"
e78a59f5	62
7368a6c8	63	/* import */
7368a6c8	64	extern ServerOptions options;
c023a130	65	extern int use_privsep;
bc7dfc06	66	extern Buffer loginmsg;
7368a6c8	67
01dafcb5	68	/* Debugging messages */
	69	Buffer auth_debug;
	70	int auth_debug_init;
	71
7368a6c8	72	/*
c6a69271	73	* Check if the user is allowed to log in via ssh. If user is listed
	74	* in DenyUsers or one of user's groups is listed in DenyGroups, false
	75	* will be returned. If AllowUsers isn't empty and user isn't listed
	76	* there, or if AllowGroups isn't empty and one of user's groups isn't
	77	* listed there, false will be returned.
7368a6c8	78	* If the user's shell is not executable, false will be returned.
6ae2364d	79	* Otherwise true is returned.
7368a6c8	80	*/
a306f2dd	81	int
7368a6c8	82	allowed_user(struct passwd * pw)
	83	{
	84	struct stat st;
da67ae18	85	const char hostname = NULL, ipaddr = NULL, *passwd = NULL;
614dee3a	86	char *shell;
2ceb8101	87	u_int i;
f14ca4a4	88	#ifdef USE_SHADOW
3e6e3da0	89	struct spwd *spw = NULL;
e2ef2342	90	#endif
7368a6c8	91
7368a6c8	92	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
c6a69271	93	if (!pw \|\| !pw->pw_name)
7368a6c8	94	return 0;
7368a6c8	95
f14ca4a4	96	#ifdef USE_SHADOW
3e6e3da0	97	if (!options.use_pam)
	98	spw = getspnam(pw->pw_name);
	99	#ifdef HAS_SHADOW_EXPIRE
f14ca4a4	100	if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
f14ca4a4	101	return 0;
3e6e3da0	102	#endif /* HAS_SHADOW_EXPIRE */
f14ca4a4	103	#endif /* USE_SHADOW */
3e6e3da0	104
aff51935	105	/* grab passwd field for locked account check */
f14ca4a4	106	#ifdef USE_SHADOW
3e6e3da0	107	if (spw != NULL)
26d07095	108	#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
4c653d8e	109	passwd = get_iaf_password(pw);
4c653d8e	110	#else
3e6e3da0	111	passwd = spw->sp_pwdp;
26d07095	112	#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
3e6e3da0	113	#else
3e6e3da0	114	passwd = pw->pw_passwd;
b57c8e20	115	#endif
b57c8e20	116
aff51935	117	/* check for locked account */
da67ae18	118	if (!options.use_pam && passwd && *passwd) {
3e6e3da0	119	int locked = 0;
	120
	121	#ifdef LOCKED_PASSWD_STRING
	122	if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
	123	locked = 1;
	124	#endif
	125	#ifdef LOCKED_PASSWD_PREFIX
	126	if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
	127	strlen(LOCKED_PASSWD_PREFIX)) == 0)
	128	locked = 1;
	129	#endif
	130	#ifdef LOCKED_PASSWD_SUBSTR
	131	if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
	132	locked = 1;
	133	#endif
26d07095	134	#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
	135	free(passwd);
	136	#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
3e6e3da0	137	if (locked) {
	138	logit("User %.100s not allowed because account is locked",
	139	pw->pw_name);
	140	return 0;
	141	}
	142	}
	143
301e9b01	144	/*
	145	* Get the shell from the password data. An empty shell field is
	146	* legal, and means /bin/sh.
	147	*/
	148	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
	149
	150	/* deny if shell does not exists or is not executable */
b334badd	151	if (stat(shell, &st) != 0) {
bbe88b6d	152	logit("User %.100s not allowed because shell %.100s does not exist",
b334badd	153	pw->pw_name, shell);
7368a6c8	154	return 0;
b334badd	155	}
c390a3c8	156	if (S_ISREG(st.st_mode) == 0 \|\|
c390a3c8	157	(st.st_mode & (S_IXOTH\|S_IXUSR\|S_IXGRP)) == 0) {
bbe88b6d	158	logit("User %.100s not allowed because shell %.100s is not executable",
b334badd	159	pw->pw_name, shell);
7368a6c8	160	return 0;
b334badd	161	}
7368a6c8	162
2dcbac07	163	if (options.num_deny_users > 0 \|\| options.num_allow_users > 0 \|\|
2dcbac07	164	options.num_deny_groups > 0 \|\| options.num_allow_groups > 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])) {
31de8b2b	174	logit("User %.100s from %.100s not allowed "
	175	"because listed in DenyUsers",
	176	pw->pw_name, hostname);
7368a6c8	177	return 0;
b334badd	178	}
7368a6c8	179	}
	180	/* Return false if AllowUsers isn't empty and user isn't listed there */
	181	if (options.num_allow_users > 0) {
7368a6c8	182	for (i = 0; i < options.num_allow_users; i++)
762715ce	183	if (match_user(pw->pw_name, hostname, ipaddr,
80f8f24f	184	options.allow_users[i]))
7368a6c8	185	break;
7368a6c8	186	/* i < options.num_allow_users iff we break for loop */
b334badd	187	if (i >= options.num_allow_users) {
31de8b2b	188	logit("User %.100s from %.100s not allowed because "
31de8b2b	189	"not listed in AllowUsers", pw->pw_name, hostname);
7368a6c8	190	return 0;
b334badd	191	}
7368a6c8	192	}
7368a6c8	193	if (options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
c6a69271	194	/* Get the user's group access list (primary and supplementary) */
b334badd	195	if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
31de8b2b	196	logit("User %.100s from %.100s not allowed because "
31de8b2b	197	"not in any group", pw->pw_name, hostname);
7368a6c8	198	return 0;
b334badd	199	}
7368a6c8	200
c6a69271	201	/* Return false if one of user's groups is listed in DenyGroups */
	202	if (options.num_deny_groups > 0)
	203	if (ga_match(options.deny_groups,
	204	options.num_deny_groups)) {
	205	ga_free();
31de8b2b	206	logit("User %.100s from %.100s not allowed "
	207	"because a group is listed in DenyGroups",
	208	pw->pw_name, hostname);
7368a6c8	209	return 0;
c6a69271	210	}
7368a6c8	211	/*
c6a69271	212	* Return false if AllowGroups isn't empty and one of user's groups
7368a6c8	213	* isn't listed there
7368a6c8	214	*/
c6a69271	215	if (options.num_allow_groups > 0)
	216	if (!ga_match(options.allow_groups,
	217	options.num_allow_groups)) {
	218	ga_free();
31de8b2b	219	logit("User %.100s from %.100s not allowed "
	220	"because none of user's groups are listed "
	221	"in AllowGroups", pw->pw_name, hostname);
7368a6c8	222	return 0;
c6a69271	223	}
c6a69271	224	ga_free();
7368a6c8	225	}
7368a6c8	226
bc5c2025	227	#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
5ccf88cb	228	if (!sys_auth_allowed_user(pw, &loginmsg))
bc5c2025	229	return 0;
bc5c2025	230	#endif
7368a6c8	231
	232	/* We found no reason not to let this user try to log on... */
	233	return 1;
	234	}
59c97189	235
59c97189	236	void
	237	auth_log(Authctxt authctxt, int authenticated, char method, char *info)
	238	{
	239	void (authlog) (const char fmt,...) = verbose;
	240	char *authmsg;
	241
c023a130	242	if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
	243	return;
	244
59c97189	245	/* Raise logging level */
	246	if (authenticated == 1 \|\|
	247	!authctxt->valid \|\|
af4bd935	248	authctxt->failures >= options.max_authtries / 2 \|\|
59c97189	249	strcmp(method, "password") == 0)
a3568201	250	authlog = logit;
59c97189	251
	252	if (authctxt->postponed)
	253	authmsg = "Postponed";
	254	else
	255	authmsg = authenticated ? "Accepted" : "Failed";
	256
	257	authlog("%s %s for %s%.100s from %.200s port %d%s",
	258	authmsg,
	259	method,
d77347cc	260	authctxt->valid ? "" : "invalid user ",
fad3754c	261	authctxt->user,
59c97189	262	get_remote_ipaddr(),
	263	get_remote_port(),
	264	info);
56fd97d7	265
73d9dad3	266	#ifdef CUSTOM_FAILED_LOGIN
b6610e8f	267	if (authenticated == 0 && !authctxt->postponed &&
b6610e8f	268	(strcmp(method, "password") == 0 \|\|
6af6e631	269	strncmp(method, "keyboard-interactive", 20) == 0 \|\|
6af6e631	270	strcmp(method, "challenge-response") == 0))
575e336f	271	record_failed_login(authctxt->user,
575e336f	272	get_canonical_hostname(options.use_dns), "ssh");
73d9dad3	273	#endif
6039eeef	274	#ifdef SSH_AUDIT_EVENTS
2ae7f715	275	if (authenticated == 0 && !authctxt->postponed)
2ae7f715	276	audit_event(audit_classify_auth(method));
c00e4d75	277	#endif
59c97189	278	}
	279
	280	/*
15853e93	281	* Check whether root logins are disallowed.
59c97189	282	*/
59c97189	283	int
15853e93	284	auth_root_allowed(char *method)
59c97189	285	{
15853e93	286	switch (options.permit_root_login) {
15853e93	287	case PERMIT_YES:
59c97189	288	return 1;
15853e93	289	case PERMIT_NO_PASSWD:
	290	if (strcmp(method, "password") != 0)
	291	return 1;
	292	break;
	293	case PERMIT_FORCED_ONLY:
	294	if (forced_command) {
bbe88b6d	295	logit("Root login accepted for forced command.");
15853e93	296	return 1;
	297	}
	298	break;
59c97189	299	}
bbe88b6d	300	logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
15853e93	301	return 0;
59c97189	302	}
c8445989	303
	304
	305	/*
	306	* Given a template and a passwd structure, build a filename
	307	* by substituting % tokenised options. Currently, %% becomes '%',
	308	* %h becomes the home directory and %u the username.
	309	*
	310	* This returns a buffer allocated by xmalloc.
	311	*/
a980cbd7	312	static char *
a980cbd7	313	expand_authorized_keys(const char filename, struct passwd pw)
c8445989	314	{
52e3daed	315	char *file, ret[MAXPATHLEN];
52e3daed	316	int i;
c8445989	317
a980cbd7	318	file = percent_expand(filename, "h", pw->pw_dir,
a980cbd7	319	"u", pw->pw_name, (char *)NULL);
c8445989	320
	321	/*
	322	* Ensure that filename starts anchored. If not, be backward
	323	* compatible and prepend the '%h/'
	324	*/
a980cbd7	325	if (*file == '/')
	326	return (file);
	327
52e3daed	328	i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
52e3daed	329	if (i < 0 \|\| (size_t)i >= sizeof(ret))
a980cbd7	330	fatal("expand_authorized_keys: path too long");
a980cbd7	331	xfree(file);
52e3daed	332	return (xstrdup(ret));
c8445989	333	}
	334
	335	char *
	336	authorized_keys_file(struct passwd *pw)
	337	{
a980cbd7	338	return expand_authorized_keys(options.authorized_keys_file, pw);
c8445989	339	}
	340
	341	char *
	342	authorized_keys_file2(struct passwd *pw)
	343	{
a980cbd7	344	return expand_authorized_keys(options.authorized_keys_file2, pw);
c8445989	345	}
c8445989	346
d0c8ca5c	347	/* return ok if key exists in sysfile or userfile */
	348	HostStatus
	349	check_key_in_hostfiles(struct passwd pw, Key key, const char *host,
	350	const char sysfile, const char userfile)
	351	{
	352	Key *found;
	353	char *user_hostfile;
	354	struct stat st;
17a3011c	355	HostStatus host_status;
d0c8ca5c	356
	357	/* Check if we know the host and its host key. */
	358	found = key_new(key->type);
	359	host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
	360
	361	if (host_status != HOST_OK && userfile != NULL) {
	362	user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
	363	if (options.strict_modes &&
	364	(stat(user_hostfile, &st) == 0) &&
	365	((st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
184eed6a	366	(st.st_mode & 022) != 0)) {
bbe88b6d	367	logit("Authentication refused for %.100s: "
d0c8ca5c	368	"bad owner or modes for %.200s",
	369	pw->pw_name, user_hostfile);
	370	} else {
	371	temporarily_use_uid(pw);
	372	host_status = check_host_in_hostfile(user_hostfile,
	373	host, key, found, NULL);
	374	restore_uid();
	375	}
	376	xfree(user_hostfile);
	377	}
	378	key_free(found);
	379
	380	debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
	381	"ok" : "not found", host);
	382	return host_status;
	383	}
	384
	385
c8445989	386	/*
c8445989	387	* Check a given file for security. This is defined as all components
d6097023	388	* of the path to the file must be owned by either the owner of
1ddf764b	389	* of the file or root and no directories must be group or world writable.
c8445989	390	*
	391	* XXX Should any specific check be done for sym links ?
	392	*
	393	* Takes an open file descriptor, the file name, a uid and and
	394	* error buffer plus max size as arguments.
	395	*
	396	* Returns 0 on success and -1 on failure
	397	*/
	398	int
6978866a	399	secure_filename(FILE f, const char file, struct passwd *pw,
6978866a	400	char *err, size_t errlen)
c8445989	401	{
6978866a	402	uid_t uid = pw->pw_uid;
76fbdd47	403	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
c8445989	404	char *cp;
f6f02456	405	int comparehome = 0;
c8445989	406	struct stat st;
	407
	408	if (realpath(file, buf) == NULL) {
	409	snprintf(err, errlen, "realpath %s failed: %s", file,
	410	strerror(errno));
	411	return -1;
	412	}
f6f02456	413	if (realpath(pw->pw_dir, homedir) != NULL)
f6f02456	414	comparehome = 1;
c8445989	415
	416	/* check the open file to avoid races */
	417	if (fstat(fileno(f), &st) < 0 \|\|
	418	(st.st_uid != 0 && st.st_uid != uid) \|\|
	419	(st.st_mode & 022) != 0) {
	420	snprintf(err, errlen, "bad ownership or modes for file %s",
	421	buf);
	422	return -1;
	423	}
	424
	425	/* for each component of the canonical path, walking upwards */
	426	for (;;) {
	427	if ((cp = dirname(buf)) == NULL) {
	428	snprintf(err, errlen, "dirname() failed");
	429	return -1;
	430	}
	431	strlcpy(buf, cp, sizeof(buf));
	432
	433	debug3("secure_filename: checking '%s'", buf);
	434	if (stat(buf, &st) < 0 \|\|
	435	(st.st_uid != 0 && st.st_uid != uid) \|\|
	436	(st.st_mode & 022) != 0) {
184eed6a	437	snprintf(err, errlen,
c8445989	438	"bad ownership or modes for directory %s", buf);
	439	return -1;
	440	}
	441
afd501f9	442	/* If are passed the homedir then we can stop */
f6f02456	443	if (comparehome && strcmp(homedir, buf) == 0) {
afd501f9	444	debug3("secure_filename: terminating check at '%s'",
	445	buf);
	446	break;
	447	}
c8445989	448	/*
	449	* dirname should always complete with a "/" path,
	450	* but we can be paranoid and check for "." too
	451	*/
	452	if ((strcmp("/", buf) == 0) \|\| (strcmp(".", buf) == 0))
	453	break;
	454	}
	455	return 0;
	456	}
443fa1cd	457
	458	struct passwd *
	459	getpwnamallow(const char *user)
	460	{
1836f69f	461	#ifdef HAVE_LOGIN_CAP
	462	extern login_cap_t *lc;
	463	#ifdef BSD_AUTH
	464	auth_session_t *as;
	465	#endif
	466	#endif
443fa1cd	467	struct passwd *pw;
	468
	469	pw = getpwnam(user);
c2802d92	470	if (pw == NULL) {
227a6a97	471	logit("Invalid user %.100s from %.100s",
c2802d92	472	user, get_remote_ipaddr());
73d9dad3	473	#ifdef CUSTOM_FAILED_LOGIN
575e336f	474	record_failed_login(user,
575e336f	475	get_canonical_hostname(options.use_dns), "ssh");
819d3f09	476	#endif
6039eeef	477	#ifdef SSH_AUDIT_EVENTS
	478	audit_event(SSH_INVALID_USER);
	479	#endif /* SSH_AUDIT_EVENTS */
c2802d92	480	return (NULL);
	481	}
	482	if (!allowed_user(pw))
1836f69f	483	return (NULL);
	484	#ifdef HAVE_LOGIN_CAP
	485	if ((lc = login_getclass(pw->pw_class)) == NULL) {
	486	debug("unable to get login class: %s", user);
	487	return (NULL);
	488	}
	489	#ifdef BSD_AUTH
	490	if ((as = auth_open()) == NULL \|\| auth_setpwd(as, pw) != 0 \|\|
65721f9c	491	auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
1836f69f	492	debug("Approval failure for %s", user);
443fa1cd	493	pw = NULL;
1836f69f	494	}
	495	if (as != NULL)
	496	auth_close(as);
	497	#endif
	498	#endif
06bea668	499	if (pw != NULL)
	500	return (pwcopy(pw));
	501	return (NULL);
443fa1cd	502	}
01dafcb5	503
	504	void
	505	auth_debug_add(const char *fmt,...)
	506	{
	507	char buf[1024];
	508	va_list args;
	509
	510	if (!auth_debug_init)
	511	return;
	512
	513	va_start(args, fmt);
	514	vsnprintf(buf, sizeof(buf), fmt, args);
	515	va_end(args);
	516	buffer_put_cstring(&auth_debug, buf);
	517	}
	518
	519	void
	520	auth_debug_send(void)
	521	{
	522	char *msg;
	523
	524	if (!auth_debug_init)
	525	return;
	526	while (buffer_len(&auth_debug)) {
	527	msg = buffer_get_string(&auth_debug, NULL);
	528	packet_send_debug("%s", msg);
	529	xfree(msg);
	530	}
	531	}
	532
	533	void
	534	auth_debug_reset(void)
	535	{
	536	if (auth_debug_init)
	537	buffer_clear(&auth_debug);
	538	else {
	539	buffer_init(&auth_debug);
	540	auth_debug_init = 1;
	541	}
	542	}
96d0bf74	543
	544	struct passwd *
	545	fakepw(void)
	546	{
	547	static struct passwd fake;
	548
	549	memset(&fake, 0, sizeof(fake));
	550	fake.pw_name = "NOUSER";
	551	fake.pw_passwd =
b6453d99	552	"$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
96d0bf74	553	fake.pw_gecos = "NOUSER";
f6be21a0	554	fake.pw_uid = (uid_t)-1;
f6be21a0	555	fake.pw_gid = (gid_t)-1;
96d0bf74	556	#ifdef HAVE_PW_CLASS_IN_PASSWD
	557	fake.pw_class = "";
	558	#endif
	559	fake.pw_dir = "/nonexist";
	560	fake.pw_shell = "/nonexist";
	561
	562	return (&fake);
	563	}