[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 1.60 2005/06/17 02:44:32 djm Exp $");

#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 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)
#ifdef HAVE_LIBIAF
		passwd = get_iaf_password(pw);
#else
		passwd = spw->sp_pwdp;
#endif /* HAVE_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 (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;

	/* 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) {
		ssh_audit_event_t event;

		debug3("audit failed auth attempt, method %s euid %d",
		    method, (int)geteuid());
		/*
		 * Because the auth loop is used in both monitor and slave,
		 * we must be careful to send each event only once and with
		 * enough privs to write the event.
		 */
		event = audit_classify_auth(method);
		switch(event) {
		case SSH_AUTH_FAIL_NONE:
		case SSH_AUTH_FAIL_PASSWD:
		case SSH_AUTH_FAIL_KBDINT:
			if (geteuid() == 0)
				audit_event(event);
			break;
		case SSH_AUTH_FAIL_PUBKEY:
		case SSH_AUTH_FAIL_HOSTBASED:
		case SSH_AUTH_FAIL_GSSAPI:
			/*
			 * This is required to handle the case where privsep
			 * is enabled but it's root logging in, since
			 * use_privsep won't be cleared until after a
			 * successful login.
			 */
			if (geteuid() == 0)
				audit_event(event);
			else
				PRIVSEP(audit_event(event));
			break;
		default:
			error("unknown authentication audit event %d", event);
		}
	}
#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.
 */
static char *
expand_authorized_keys(const char *filename, struct passwd *pw)
{
	char *file, *ret;

	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);

	ret = xmalloc(MAXPATHLEN);
	if (strlcpy(ret, pw->pw_dir, MAXPATHLEN) >= MAXPATHLEN ||
	    strlcat(ret, "/", MAXPATHLEN) >= MAXPATHLEN ||
	    strlcat(ret, file, MAXPATHLEN) >= MAXPATHLEN)
		fatal("expand_authorized_keys: path too long");

	xfree(file);
	return (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
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"
2ceb8101	26	RCSID("$OpenBSD: auth.c,v 1.60 2005/06/17 02:44:32 djm Exp $");
7368a6c8	27
c1ef8333	28	#ifdef HAVE_LOGIN_H
	29	#include <login.h>
	30	#endif
f14ca4a4	31	#ifdef USE_SHADOW
4cb5ffa0	32	#include <shadow.h>
f14ca4a4	33	#endif
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"
5f1f36b5	50	#include "misc.h"
01dafcb5	51	#include "bufaux.h"
01dafcb5	52	#include "packet.h"
575e336f	53	#include "loginrec.h"
c00e4d75	54	#include "monitor_wrap.h"
e78a59f5	55
7368a6c8	56	/* import */
7368a6c8	57	extern ServerOptions options;
bc7dfc06	58	extern Buffer loginmsg;
7368a6c8	59
01dafcb5	60	/* Debugging messages */
	61	Buffer auth_debug;
	62	int auth_debug_init;
	63
7368a6c8	64	/*
c6a69271	65	* Check if the user is allowed to log in via ssh. If user is listed
	66	* in DenyUsers or one of user's groups is listed in DenyGroups, false
	67	* will be returned. If AllowUsers isn't empty and user isn't listed
	68	* there, or if AllowGroups isn't empty and one of user's groups isn't
	69	* listed there, false will be returned.
7368a6c8	70	* If the user's shell is not executable, false will be returned.
6ae2364d	71	* Otherwise true is returned.
7368a6c8	72	*/
a306f2dd	73	int
7368a6c8	74	allowed_user(struct passwd * pw)
	75	{
	76	struct stat st;
da67ae18	77	const char hostname = NULL, ipaddr = NULL, *passwd = NULL;
614dee3a	78	char *shell;
2ceb8101	79	u_int i;
f14ca4a4	80	#ifdef USE_SHADOW
3e6e3da0	81	struct spwd *spw = NULL;
e2ef2342	82	#endif
7368a6c8	83
7368a6c8	84	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
c6a69271	85	if (!pw \|\| !pw->pw_name)
7368a6c8	86	return 0;
7368a6c8	87
f14ca4a4	88	#ifdef USE_SHADOW
3e6e3da0	89	if (!options.use_pam)
	90	spw = getspnam(pw->pw_name);
	91	#ifdef HAS_SHADOW_EXPIRE
f14ca4a4	92	if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
f14ca4a4	93	return 0;
3e6e3da0	94	#endif /* HAS_SHADOW_EXPIRE */
f14ca4a4	95	#endif /* USE_SHADOW */
3e6e3da0	96
aff51935	97	/* grab passwd field for locked account check */
f14ca4a4	98	#ifdef USE_SHADOW
3e6e3da0	99	if (spw != NULL)
4c653d8e	100	#ifdef HAVE_LIBIAF
	101	passwd = get_iaf_password(pw);
	102	#else
3e6e3da0	103	passwd = spw->sp_pwdp;
4c653d8e	104	#endif /* HAVE_LIBIAF */
3e6e3da0	105	#else
3e6e3da0	106	passwd = pw->pw_passwd;
b57c8e20	107	#endif
b57c8e20	108
aff51935	109	/* check for locked account */
da67ae18	110	if (!options.use_pam && passwd && *passwd) {
3e6e3da0	111	int locked = 0;
	112
	113	#ifdef LOCKED_PASSWD_STRING
	114	if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
	115	locked = 1;
	116	#endif
	117	#ifdef LOCKED_PASSWD_PREFIX
	118	if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
	119	strlen(LOCKED_PASSWD_PREFIX)) == 0)
	120	locked = 1;
	121	#endif
	122	#ifdef LOCKED_PASSWD_SUBSTR
	123	if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
	124	locked = 1;
	125	#endif
	126	if (locked) {
	127	logit("User %.100s not allowed because account is locked",
	128	pw->pw_name);
	129	return 0;
	130	}
	131	}
	132
301e9b01	133	/*
	134	* Get the shell from the password data. An empty shell field is
	135	* legal, and means /bin/sh.
	136	*/
	137	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
	138
	139	/* deny if shell does not exists or is not executable */
b334badd	140	if (stat(shell, &st) != 0) {
bbe88b6d	141	logit("User %.100s not allowed because shell %.100s does not exist",
b334badd	142	pw->pw_name, shell);
7368a6c8	143	return 0;
b334badd	144	}
c390a3c8	145	if (S_ISREG(st.st_mode) == 0 \|\|
c390a3c8	146	(st.st_mode & (S_IXOTH\|S_IXUSR\|S_IXGRP)) == 0) {
bbe88b6d	147	logit("User %.100s not allowed because shell %.100s is not executable",
b334badd	148	pw->pw_name, shell);
7368a6c8	149	return 0;
b334badd	150	}
7368a6c8	151
2dcbac07	152	if (options.num_deny_users > 0 \|\| options.num_allow_users > 0 \|\|
2dcbac07	153	options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
c5a7d788	154	hostname = get_canonical_hostname(options.use_dns);
6805fc56	155	ipaddr = get_remote_ipaddr();
	156	}
	157
7368a6c8	158	/* Return false if user is listed in DenyUsers */
7368a6c8	159	if (options.num_deny_users > 0) {
7368a6c8	160	for (i = 0; i < options.num_deny_users; i++)
762715ce	161	if (match_user(pw->pw_name, hostname, ipaddr,
b334badd	162	options.deny_users[i])) {
31de8b2b	163	logit("User %.100s from %.100s not allowed "
	164	"because listed in DenyUsers",
	165	pw->pw_name, hostname);
7368a6c8	166	return 0;
b334badd	167	}
7368a6c8	168	}
	169	/* Return false if AllowUsers isn't empty and user isn't listed there */
	170	if (options.num_allow_users > 0) {
7368a6c8	171	for (i = 0; i < options.num_allow_users; i++)
762715ce	172	if (match_user(pw->pw_name, hostname, ipaddr,
80f8f24f	173	options.allow_users[i]))
7368a6c8	174	break;
7368a6c8	175	/* i < options.num_allow_users iff we break for loop */
b334badd	176	if (i >= options.num_allow_users) {
31de8b2b	177	logit("User %.100s from %.100s not allowed because "
31de8b2b	178	"not listed in AllowUsers", pw->pw_name, hostname);
7368a6c8	179	return 0;
b334badd	180	}
7368a6c8	181	}
7368a6c8	182	if (options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
c6a69271	183	/* Get the user's group access list (primary and supplementary) */
b334badd	184	if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
31de8b2b	185	logit("User %.100s from %.100s not allowed because "
31de8b2b	186	"not in any group", pw->pw_name, hostname);
7368a6c8	187	return 0;
b334badd	188	}
7368a6c8	189
c6a69271	190	/* Return false if one of user's groups is listed in DenyGroups */
	191	if (options.num_deny_groups > 0)
	192	if (ga_match(options.deny_groups,
	193	options.num_deny_groups)) {
	194	ga_free();
31de8b2b	195	logit("User %.100s from %.100s not allowed "
	196	"because a group is listed in DenyGroups",
	197	pw->pw_name, hostname);
7368a6c8	198	return 0;
c6a69271	199	}
7368a6c8	200	/*
c6a69271	201	* Return false if AllowGroups isn't empty and one of user's groups
7368a6c8	202	* isn't listed there
7368a6c8	203	*/
c6a69271	204	if (options.num_allow_groups > 0)
	205	if (!ga_match(options.allow_groups,
	206	options.num_allow_groups)) {
	207	ga_free();
31de8b2b	208	logit("User %.100s from %.100s not allowed "
	209	"because none of user's groups are listed "
	210	"in AllowGroups", pw->pw_name, hostname);
7368a6c8	211	return 0;
c6a69271	212	}
c6a69271	213	ga_free();
7368a6c8	214	}
7368a6c8	215
bc5c2025	216	#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
5ccf88cb	217	if (!sys_auth_allowed_user(pw, &loginmsg))
bc5c2025	218	return 0;
bc5c2025	219	#endif
7368a6c8	220
	221	/* We found no reason not to let this user try to log on... */
	222	return 1;
	223	}
59c97189	224
59c97189	225	void
	226	auth_log(Authctxt authctxt, int authenticated, char method, char *info)
	227	{
	228	void (authlog) (const char fmt,...) = verbose;
	229	char *authmsg;
	230
	231	/* Raise logging level */
	232	if (authenticated == 1 \|\|
	233	!authctxt->valid \|\|
af4bd935	234	authctxt->failures >= options.max_authtries / 2 \|\|
59c97189	235	strcmp(method, "password") == 0)
a3568201	236	authlog = logit;
59c97189	237
	238	if (authctxt->postponed)
	239	authmsg = "Postponed";
	240	else
	241	authmsg = authenticated ? "Accepted" : "Failed";
	242
	243	authlog("%s %s for %s%.100s from %.200s port %d%s",
	244	authmsg,
	245	method,
d77347cc	246	authctxt->valid ? "" : "invalid user ",
fad3754c	247	authctxt->user,
59c97189	248	get_remote_ipaddr(),
	249	get_remote_port(),
	250	info);
56fd97d7	251
73d9dad3	252	#ifdef CUSTOM_FAILED_LOGIN
b6610e8f	253	if (authenticated == 0 && !authctxt->postponed &&
b6610e8f	254	(strcmp(method, "password") == 0 \|\|
6af6e631	255	strncmp(method, "keyboard-interactive", 20) == 0 \|\|
6af6e631	256	strcmp(method, "challenge-response") == 0))
575e336f	257	record_failed_login(authctxt->user,
575e336f	258	get_canonical_hostname(options.use_dns), "ssh");
73d9dad3	259	#endif
6039eeef	260	#ifdef SSH_AUDIT_EVENTS
c00e4d75	261	if (authenticated == 0 && !authctxt->postponed) {
	262	ssh_audit_event_t event;
	263
	264	debug3("audit failed auth attempt, method %s euid %d",
	265	method, (int)geteuid());
	266	/*
	267	* Because the auth loop is used in both monitor and slave,
	268	* we must be careful to send each event only once and with
	269	* enough privs to write the event.
	270	*/
	271	event = audit_classify_auth(method);
	272	switch(event) {
6039eeef	273	case SSH_AUTH_FAIL_NONE:
	274	case SSH_AUTH_FAIL_PASSWD:
	275	case SSH_AUTH_FAIL_KBDINT:
c00e4d75	276	if (geteuid() == 0)
	277	audit_event(event);
	278	break;
6039eeef	279	case SSH_AUTH_FAIL_PUBKEY:
	280	case SSH_AUTH_FAIL_HOSTBASED:
	281	case SSH_AUTH_FAIL_GSSAPI:
c00e4d75	282	/*
	283	* This is required to handle the case where privsep
	284	* is enabled but it's root logging in, since
	285	* use_privsep won't be cleared until after a
	286	* successful login.
	287	*/
	288	if (geteuid() == 0)
	289	audit_event(event);
	290	else
	291	PRIVSEP(audit_event(event));
	292	break;
	293	default:
	294	error("unknown authentication audit event %d", event);
	295	}
	296	}
	297	#endif
59c97189	298	}
	299
	300	/*
15853e93	301	* Check whether root logins are disallowed.
59c97189	302	*/
59c97189	303	int
15853e93	304	auth_root_allowed(char *method)
59c97189	305	{
15853e93	306	switch (options.permit_root_login) {
15853e93	307	case PERMIT_YES:
59c97189	308	return 1;
15853e93	309	break;
	310	case PERMIT_NO_PASSWD:
	311	if (strcmp(method, "password") != 0)
	312	return 1;
	313	break;
	314	case PERMIT_FORCED_ONLY:
	315	if (forced_command) {
bbe88b6d	316	logit("Root login accepted for forced command.");
15853e93	317	return 1;
	318	}
	319	break;
59c97189	320	}
bbe88b6d	321	logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
15853e93	322	return 0;
59c97189	323	}
c8445989	324
	325
	326	/*
	327	* Given a template and a passwd structure, build a filename
	328	* by substituting % tokenised options. Currently, %% becomes '%',
	329	* %h becomes the home directory and %u the username.
	330	*
	331	* This returns a buffer allocated by xmalloc.
	332	*/
a980cbd7	333	static char *
a980cbd7	334	expand_authorized_keys(const char filename, struct passwd pw)
c8445989	335	{
a980cbd7	336	char file, ret;
c8445989	337
a980cbd7	338	file = percent_expand(filename, "h", pw->pw_dir,
a980cbd7	339	"u", pw->pw_name, (char *)NULL);
c8445989	340
	341	/*
	342	* Ensure that filename starts anchored. If not, be backward
	343	* compatible and prepend the '%h/'
	344	*/
a980cbd7	345	if (*file == '/')
	346	return (file);
	347
	348	ret = xmalloc(MAXPATHLEN);
	349	if (strlcpy(ret, pw->pw_dir, MAXPATHLEN) >= MAXPATHLEN \|\|
	350	strlcat(ret, "/", MAXPATHLEN) >= MAXPATHLEN \|\|
	351	strlcat(ret, file, MAXPATHLEN) >= MAXPATHLEN)
	352	fatal("expand_authorized_keys: path too long");
c8445989	353
a980cbd7	354	xfree(file);
a980cbd7	355	return (ret);
c8445989	356	}
	357
	358	char *
	359	authorized_keys_file(struct passwd *pw)
	360	{
a980cbd7	361	return expand_authorized_keys(options.authorized_keys_file, pw);
c8445989	362	}
	363
	364	char *
	365	authorized_keys_file2(struct passwd *pw)
	366	{
a980cbd7	367	return expand_authorized_keys(options.authorized_keys_file2, pw);
c8445989	368	}
c8445989	369
d0c8ca5c	370	/* return ok if key exists in sysfile or userfile */
	371	HostStatus
	372	check_key_in_hostfiles(struct passwd pw, Key key, const char *host,
	373	const char sysfile, const char userfile)
	374	{
	375	Key *found;
	376	char *user_hostfile;
	377	struct stat st;
17a3011c	378	HostStatus host_status;
d0c8ca5c	379
	380	/* Check if we know the host and its host key. */
	381	found = key_new(key->type);
	382	host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
	383
	384	if (host_status != HOST_OK && userfile != NULL) {
	385	user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
	386	if (options.strict_modes &&
	387	(stat(user_hostfile, &st) == 0) &&
	388	((st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
184eed6a	389	(st.st_mode & 022) != 0)) {
bbe88b6d	390	logit("Authentication refused for %.100s: "
d0c8ca5c	391	"bad owner or modes for %.200s",
	392	pw->pw_name, user_hostfile);
	393	} else {
	394	temporarily_use_uid(pw);
	395	host_status = check_host_in_hostfile(user_hostfile,
	396	host, key, found, NULL);
	397	restore_uid();
	398	}
	399	xfree(user_hostfile);
	400	}
	401	key_free(found);
	402
	403	debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
	404	"ok" : "not found", host);
	405	return host_status;
	406	}
	407
	408
c8445989	409	/*
c8445989	410	* Check a given file for security. This is defined as all components
d6097023	411	* of the path to the file must be owned by either the owner of
1ddf764b	412	* of the file or root and no directories must be group or world writable.
c8445989	413	*
	414	* XXX Should any specific check be done for sym links ?
	415	*
	416	* Takes an open file descriptor, the file name, a uid and and
	417	* error buffer plus max size as arguments.
	418	*
	419	* Returns 0 on success and -1 on failure
	420	*/
	421	int
6978866a	422	secure_filename(FILE f, const char file, struct passwd *pw,
6978866a	423	char *err, size_t errlen)
c8445989	424	{
6978866a	425	uid_t uid = pw->pw_uid;
76fbdd47	426	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
c8445989	427	char *cp;
f6f02456	428	int comparehome = 0;
c8445989	429	struct stat st;
	430
	431	if (realpath(file, buf) == NULL) {
	432	snprintf(err, errlen, "realpath %s failed: %s", file,
	433	strerror(errno));
	434	return -1;
	435	}
f6f02456	436	if (realpath(pw->pw_dir, homedir) != NULL)
f6f02456	437	comparehome = 1;
c8445989	438
	439	/* check the open file to avoid races */
	440	if (fstat(fileno(f), &st) < 0 \|\|
	441	(st.st_uid != 0 && st.st_uid != uid) \|\|
	442	(st.st_mode & 022) != 0) {
	443	snprintf(err, errlen, "bad ownership or modes for file %s",
	444	buf);
	445	return -1;
	446	}
	447
	448	/* for each component of the canonical path, walking upwards */
	449	for (;;) {
	450	if ((cp = dirname(buf)) == NULL) {
	451	snprintf(err, errlen, "dirname() failed");
	452	return -1;
	453	}
	454	strlcpy(buf, cp, sizeof(buf));
	455
	456	debug3("secure_filename: checking '%s'", buf);
	457	if (stat(buf, &st) < 0 \|\|
	458	(st.st_uid != 0 && st.st_uid != uid) \|\|
	459	(st.st_mode & 022) != 0) {
184eed6a	460	snprintf(err, errlen,
c8445989	461	"bad ownership or modes for directory %s", buf);
	462	return -1;
	463	}
	464
afd501f9	465	/* If are passed the homedir then we can stop */
f6f02456	466	if (comparehome && strcmp(homedir, buf) == 0) {
afd501f9	467	debug3("secure_filename: terminating check at '%s'",
	468	buf);
	469	break;
	470	}
c8445989	471	/*
	472	* dirname should always complete with a "/" path,
	473	* but we can be paranoid and check for "." too
	474	*/
	475	if ((strcmp("/", buf) == 0) \|\| (strcmp(".", buf) == 0))
	476	break;
	477	}
	478	return 0;
	479	}
443fa1cd	480
	481	struct passwd *
	482	getpwnamallow(const char *user)
	483	{
1836f69f	484	#ifdef HAVE_LOGIN_CAP
	485	extern login_cap_t *lc;
	486	#ifdef BSD_AUTH
	487	auth_session_t *as;
	488	#endif
	489	#endif
443fa1cd	490	struct passwd *pw;
	491
	492	pw = getpwnam(user);
c2802d92	493	if (pw == NULL) {
227a6a97	494	logit("Invalid user %.100s from %.100s",
c2802d92	495	user, get_remote_ipaddr());
73d9dad3	496	#ifdef CUSTOM_FAILED_LOGIN
575e336f	497	record_failed_login(user,
575e336f	498	get_canonical_hostname(options.use_dns), "ssh");
819d3f09	499	#endif
6039eeef	500	#ifdef SSH_AUDIT_EVENTS
	501	audit_event(SSH_INVALID_USER);
	502	#endif /* SSH_AUDIT_EVENTS */
c2802d92	503	return (NULL);
	504	}
	505	if (!allowed_user(pw))
1836f69f	506	return (NULL);
	507	#ifdef HAVE_LOGIN_CAP
	508	if ((lc = login_getclass(pw->pw_class)) == NULL) {
	509	debug("unable to get login class: %s", user);
	510	return (NULL);
	511	}
	512	#ifdef BSD_AUTH
	513	if ((as = auth_open()) == NULL \|\| auth_setpwd(as, pw) != 0 \|\|
65721f9c	514	auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
1836f69f	515	debug("Approval failure for %s", user);
443fa1cd	516	pw = NULL;
1836f69f	517	}
	518	if (as != NULL)
	519	auth_close(as);
	520	#endif
	521	#endif
06bea668	522	if (pw != NULL)
	523	return (pwcopy(pw));
	524	return (NULL);
443fa1cd	525	}
01dafcb5	526
	527	void
	528	auth_debug_add(const char *fmt,...)
	529	{
	530	char buf[1024];
	531	va_list args;
	532
	533	if (!auth_debug_init)
	534	return;
	535
	536	va_start(args, fmt);
	537	vsnprintf(buf, sizeof(buf), fmt, args);
	538	va_end(args);
	539	buffer_put_cstring(&auth_debug, buf);
	540	}
	541
	542	void
	543	auth_debug_send(void)
	544	{
	545	char *msg;
	546
	547	if (!auth_debug_init)
	548	return;
	549	while (buffer_len(&auth_debug)) {
	550	msg = buffer_get_string(&auth_debug, NULL);
	551	packet_send_debug("%s", msg);
	552	xfree(msg);
	553	}
	554	}
	555
	556	void
	557	auth_debug_reset(void)
	558	{
	559	if (auth_debug_init)
	560	buffer_clear(&auth_debug);
	561	else {
	562	buffer_init(&auth_debug);
	563	auth_debug_init = 1;
	564	}
	565	}
96d0bf74	566
	567	struct passwd *
	568	fakepw(void)
	569	{
	570	static struct passwd fake;
	571
	572	memset(&fake, 0, sizeof(fake));
	573	fake.pw_name = "NOUSER";
	574	fake.pw_passwd =
b6453d99	575	"$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
96d0bf74	576	fake.pw_gecos = "NOUSER";
f6be21a0	577	fake.pw_uid = (uid_t)-1;
f6be21a0	578	fake.pw_gid = (gid_t)-1;
96d0bf74	579	#ifdef HAVE_PW_CLASS_IN_PASSWD
	580	fake.pw_class = "";
	581	#endif
	582	fake.pw_dir = "/nonexist";
	583	fake.pw_shell = "/nonexist";
	584
	585	return (&fake);
	586	}