[openssh.git] / auth.c

/* $OpenBSD: auth.c,v 1.67 2006/03/30 11:40:21 dtucker 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
#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) {
		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;
	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
c023a130	1	/* $OpenBSD: auth.c,v 1.67 2006/03/30 11:40:21 dtucker 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
c1ef8333	34	#ifdef HAVE_LOGIN_H
	35	#include <login.h>
	36	#endif
f14ca4a4	37	#ifdef USE_SHADOW
4cb5ffa0	38	#include <shadow.h>
f14ca4a4	39	#endif
7368a6c8	40
b4d02860	41	#ifdef HAVE_LIBGEN_H
c8445989	42	#include <libgen.h>
b4d02860	43	#endif
c8445989	44
42f11eb2	45	#include "xmalloc.h"
	46	#include "match.h"
	47	#include "groupaccess.h"
	48	#include "log.h"
	49	#include "servconf.h"
e78a59f5	50	#include "auth.h"
59c97189	51	#include "auth-options.h"
42f11eb2	52	#include "canohost.h"
c8445989	53	#include "buffer.h"
c8445989	54	#include "bufaux.h"
d0c8ca5c	55	#include "uidswap.h"
5f1f36b5	56	#include "misc.h"
01dafcb5	57	#include "bufaux.h"
01dafcb5	58	#include "packet.h"
575e336f	59	#include "loginrec.h"
c00e4d75	60	#include "monitor_wrap.h"
e78a59f5	61
7368a6c8	62	/* import */
7368a6c8	63	extern ServerOptions options;
c023a130	64	extern int use_privsep;
bc7dfc06	65	extern Buffer loginmsg;
7368a6c8	66
01dafcb5	67	/* Debugging messages */
	68	Buffer auth_debug;
	69	int auth_debug_init;
	70
7368a6c8	71	/*
c6a69271	72	* Check if the user is allowed to log in via ssh. If user is listed
	73	* in DenyUsers or one of user's groups is listed in DenyGroups, false
	74	* will be returned. If AllowUsers isn't empty and user isn't listed
	75	* there, or if AllowGroups isn't empty and one of user's groups isn't
	76	* listed there, false will be returned.
7368a6c8	77	* If the user's shell is not executable, false will be returned.
6ae2364d	78	* Otherwise true is returned.
7368a6c8	79	*/
a306f2dd	80	int
7368a6c8	81	allowed_user(struct passwd * pw)
	82	{
	83	struct stat st;
da67ae18	84	const char hostname = NULL, ipaddr = NULL, *passwd = NULL;
614dee3a	85	char *shell;
2ceb8101	86	u_int i;
f14ca4a4	87	#ifdef USE_SHADOW
3e6e3da0	88	struct spwd *spw = NULL;
e2ef2342	89	#endif
7368a6c8	90
7368a6c8	91	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
c6a69271	92	if (!pw \|\| !pw->pw_name)
7368a6c8	93	return 0;
7368a6c8	94
f14ca4a4	95	#ifdef USE_SHADOW
3e6e3da0	96	if (!options.use_pam)
	97	spw = getspnam(pw->pw_name);
	98	#ifdef HAS_SHADOW_EXPIRE
f14ca4a4	99	if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
f14ca4a4	100	return 0;
3e6e3da0	101	#endif /* HAS_SHADOW_EXPIRE */
f14ca4a4	102	#endif /* USE_SHADOW */
3e6e3da0	103
aff51935	104	/* grab passwd field for locked account check */
f14ca4a4	105	#ifdef USE_SHADOW
3e6e3da0	106	if (spw != NULL)
26d07095	107	#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
4c653d8e	108	passwd = get_iaf_password(pw);
4c653d8e	109	#else
3e6e3da0	110	passwd = spw->sp_pwdp;
26d07095	111	#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
3e6e3da0	112	#else
3e6e3da0	113	passwd = pw->pw_passwd;
b57c8e20	114	#endif
b57c8e20	115
aff51935	116	/* check for locked account */
da67ae18	117	if (!options.use_pam && passwd && *passwd) {
3e6e3da0	118	int locked = 0;
	119
	120	#ifdef LOCKED_PASSWD_STRING
	121	if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
	122	locked = 1;
	123	#endif
	124	#ifdef LOCKED_PASSWD_PREFIX
	125	if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
	126	strlen(LOCKED_PASSWD_PREFIX)) == 0)
	127	locked = 1;
	128	#endif
	129	#ifdef LOCKED_PASSWD_SUBSTR
	130	if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
	131	locked = 1;
	132	#endif
26d07095	133	#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
	134	free(passwd);
	135	#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
3e6e3da0	136	if (locked) {
	137	logit("User %.100s not allowed because account is locked",
	138	pw->pw_name);
	139	return 0;
	140	}
	141	}
	142
301e9b01	143	/*
	144	* Get the shell from the password data. An empty shell field is
	145	* legal, and means /bin/sh.
	146	*/
	147	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
	148
	149	/* deny if shell does not exists or is not executable */
b334badd	150	if (stat(shell, &st) != 0) {
bbe88b6d	151	logit("User %.100s not allowed because shell %.100s does not exist",
b334badd	152	pw->pw_name, shell);
7368a6c8	153	return 0;
b334badd	154	}
c390a3c8	155	if (S_ISREG(st.st_mode) == 0 \|\|
c390a3c8	156	(st.st_mode & (S_IXOTH\|S_IXUSR\|S_IXGRP)) == 0) {
bbe88b6d	157	logit("User %.100s not allowed because shell %.100s is not executable",
b334badd	158	pw->pw_name, shell);
7368a6c8	159	return 0;
b334badd	160	}
7368a6c8	161
2dcbac07	162	if (options.num_deny_users > 0 \|\| options.num_allow_users > 0 \|\|
2dcbac07	163	options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
c5a7d788	164	hostname = get_canonical_hostname(options.use_dns);
6805fc56	165	ipaddr = get_remote_ipaddr();
	166	}
	167
7368a6c8	168	/* Return false if user is listed in DenyUsers */
7368a6c8	169	if (options.num_deny_users > 0) {
7368a6c8	170	for (i = 0; i < options.num_deny_users; i++)
762715ce	171	if (match_user(pw->pw_name, hostname, ipaddr,
b334badd	172	options.deny_users[i])) {
31de8b2b	173	logit("User %.100s from %.100s not allowed "
	174	"because listed in DenyUsers",
	175	pw->pw_name, hostname);
7368a6c8	176	return 0;
b334badd	177	}
7368a6c8	178	}
	179	/* Return false if AllowUsers isn't empty and user isn't listed there */
	180	if (options.num_allow_users > 0) {
7368a6c8	181	for (i = 0; i < options.num_allow_users; i++)
762715ce	182	if (match_user(pw->pw_name, hostname, ipaddr,
80f8f24f	183	options.allow_users[i]))
7368a6c8	184	break;
7368a6c8	185	/* i < options.num_allow_users iff we break for loop */
b334badd	186	if (i >= options.num_allow_users) {
31de8b2b	187	logit("User %.100s from %.100s not allowed because "
31de8b2b	188	"not listed in AllowUsers", pw->pw_name, hostname);
7368a6c8	189	return 0;
b334badd	190	}
7368a6c8	191	}
7368a6c8	192	if (options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
c6a69271	193	/* Get the user's group access list (primary and supplementary) */
b334badd	194	if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
31de8b2b	195	logit("User %.100s from %.100s not allowed because "
31de8b2b	196	"not in any group", pw->pw_name, hostname);
7368a6c8	197	return 0;
b334badd	198	}
7368a6c8	199
c6a69271	200	/* Return false if one of user's groups is listed in DenyGroups */
	201	if (options.num_deny_groups > 0)
	202	if (ga_match(options.deny_groups,
	203	options.num_deny_groups)) {
	204	ga_free();
31de8b2b	205	logit("User %.100s from %.100s not allowed "
	206	"because a group is listed in DenyGroups",
	207	pw->pw_name, hostname);
7368a6c8	208	return 0;
c6a69271	209	}
7368a6c8	210	/*
c6a69271	211	* Return false if AllowGroups isn't empty and one of user's groups
7368a6c8	212	* isn't listed there
7368a6c8	213	*/
c6a69271	214	if (options.num_allow_groups > 0)
	215	if (!ga_match(options.allow_groups,
	216	options.num_allow_groups)) {
	217	ga_free();
31de8b2b	218	logit("User %.100s from %.100s not allowed "
	219	"because none of user's groups are listed "
	220	"in AllowGroups", pw->pw_name, hostname);
7368a6c8	221	return 0;
c6a69271	222	}
c6a69271	223	ga_free();
7368a6c8	224	}
7368a6c8	225
bc5c2025	226	#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
5ccf88cb	227	if (!sys_auth_allowed_user(pw, &loginmsg))
bc5c2025	228	return 0;
bc5c2025	229	#endif
7368a6c8	230
	231	/* We found no reason not to let this user try to log on... */
	232	return 1;
	233	}
59c97189	234
59c97189	235	void
	236	auth_log(Authctxt authctxt, int authenticated, char method, char *info)
	237	{
	238	void (authlog) (const char fmt,...) = verbose;
	239	char *authmsg;
	240
c023a130	241	if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
	242	return;
	243
59c97189	244	/* Raise logging level */
	245	if (authenticated == 1 \|\|
	246	!authctxt->valid \|\|
af4bd935	247	authctxt->failures >= options.max_authtries / 2 \|\|
59c97189	248	strcmp(method, "password") == 0)
a3568201	249	authlog = logit;
59c97189	250
	251	if (authctxt->postponed)
	252	authmsg = "Postponed";
	253	else
	254	authmsg = authenticated ? "Accepted" : "Failed";
	255
	256	authlog("%s %s for %s%.100s from %.200s port %d%s",
	257	authmsg,
	258	method,
d77347cc	259	authctxt->valid ? "" : "invalid user ",
fad3754c	260	authctxt->user,
59c97189	261	get_remote_ipaddr(),
	262	get_remote_port(),
	263	info);
56fd97d7	264
73d9dad3	265	#ifdef CUSTOM_FAILED_LOGIN
b6610e8f	266	if (authenticated == 0 && !authctxt->postponed &&
b6610e8f	267	(strcmp(method, "password") == 0 \|\|
6af6e631	268	strncmp(method, "keyboard-interactive", 20) == 0 \|\|
6af6e631	269	strcmp(method, "challenge-response") == 0))
575e336f	270	record_failed_login(authctxt->user,
575e336f	271	get_canonical_hostname(options.use_dns), "ssh");
73d9dad3	272	#endif
6039eeef	273	#ifdef SSH_AUDIT_EVENTS
c00e4d75	274	if (authenticated == 0 && !authctxt->postponed) {
	275	ssh_audit_event_t event;
	276
	277	debug3("audit failed auth attempt, method %s euid %d",
	278	method, (int)geteuid());
	279	/*
	280	* Because the auth loop is used in both monitor and slave,
	281	* we must be careful to send each event only once and with
	282	* enough privs to write the event.
	283	*/
	284	event = audit_classify_auth(method);
	285	switch(event) {
6039eeef	286	case SSH_AUTH_FAIL_NONE:
	287	case SSH_AUTH_FAIL_PASSWD:
	288	case SSH_AUTH_FAIL_KBDINT:
c00e4d75	289	if (geteuid() == 0)
	290	audit_event(event);
	291	break;
6039eeef	292	case SSH_AUTH_FAIL_PUBKEY:
	293	case SSH_AUTH_FAIL_HOSTBASED:
	294	case SSH_AUTH_FAIL_GSSAPI:
c00e4d75	295	/*
	296	* This is required to handle the case where privsep
	297	* is enabled but it's root logging in, since
	298	* use_privsep won't be cleared until after a
	299	* successful login.
	300	*/
	301	if (geteuid() == 0)
	302	audit_event(event);
	303	else
	304	PRIVSEP(audit_event(event));
	305	break;
	306	default:
	307	error("unknown authentication audit event %d", event);
	308	}
	309	}
	310	#endif
59c97189	311	}
	312
	313	/*
15853e93	314	* Check whether root logins are disallowed.
59c97189	315	*/
59c97189	316	int
15853e93	317	auth_root_allowed(char *method)
59c97189	318	{
15853e93	319	switch (options.permit_root_login) {
15853e93	320	case PERMIT_YES:
59c97189	321	return 1;
15853e93	322	case PERMIT_NO_PASSWD:
	323	if (strcmp(method, "password") != 0)
	324	return 1;
	325	break;
	326	case PERMIT_FORCED_ONLY:
	327	if (forced_command) {
bbe88b6d	328	logit("Root login accepted for forced command.");
15853e93	329	return 1;
	330	}
	331	break;
59c97189	332	}
bbe88b6d	333	logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
15853e93	334	return 0;
59c97189	335	}
c8445989	336
	337
	338	/*
	339	* Given a template and a passwd structure, build a filename
	340	* by substituting % tokenised options. Currently, %% becomes '%',
	341	* %h becomes the home directory and %u the username.
	342	*
	343	* This returns a buffer allocated by xmalloc.
	344	*/
a980cbd7	345	static char *
a980cbd7	346	expand_authorized_keys(const char filename, struct passwd pw)
c8445989	347	{
52e3daed	348	char *file, ret[MAXPATHLEN];
52e3daed	349	int i;
c8445989	350
a980cbd7	351	file = percent_expand(filename, "h", pw->pw_dir,
a980cbd7	352	"u", pw->pw_name, (char *)NULL);
c8445989	353
	354	/*
	355	* Ensure that filename starts anchored. If not, be backward
	356	* compatible and prepend the '%h/'
	357	*/
a980cbd7	358	if (*file == '/')
	359	return (file);
	360
52e3daed	361	i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
52e3daed	362	if (i < 0 \|\| (size_t)i >= sizeof(ret))
a980cbd7	363	fatal("expand_authorized_keys: path too long");
a980cbd7	364	xfree(file);
52e3daed	365	return (xstrdup(ret));
c8445989	366	}
	367
	368	char *
	369	authorized_keys_file(struct passwd *pw)
	370	{
a980cbd7	371	return expand_authorized_keys(options.authorized_keys_file, pw);
c8445989	372	}
	373
	374	char *
	375	authorized_keys_file2(struct passwd *pw)
	376	{
a980cbd7	377	return expand_authorized_keys(options.authorized_keys_file2, pw);
c8445989	378	}
c8445989	379
d0c8ca5c	380	/* return ok if key exists in sysfile or userfile */
	381	HostStatus
	382	check_key_in_hostfiles(struct passwd pw, Key key, const char *host,
	383	const char sysfile, const char userfile)
	384	{
	385	Key *found;
	386	char *user_hostfile;
	387	struct stat st;
17a3011c	388	HostStatus host_status;
d0c8ca5c	389
	390	/* Check if we know the host and its host key. */
	391	found = key_new(key->type);
	392	host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
	393
	394	if (host_status != HOST_OK && userfile != NULL) {
	395	user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
	396	if (options.strict_modes &&
	397	(stat(user_hostfile, &st) == 0) &&
	398	((st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
184eed6a	399	(st.st_mode & 022) != 0)) {
bbe88b6d	400	logit("Authentication refused for %.100s: "
d0c8ca5c	401	"bad owner or modes for %.200s",
	402	pw->pw_name, user_hostfile);
	403	} else {
	404	temporarily_use_uid(pw);
	405	host_status = check_host_in_hostfile(user_hostfile,
	406	host, key, found, NULL);
	407	restore_uid();
	408	}
	409	xfree(user_hostfile);
	410	}
	411	key_free(found);
	412
	413	debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
	414	"ok" : "not found", host);
	415	return host_status;
	416	}
	417
	418
c8445989	419	/*
c8445989	420	* Check a given file for security. This is defined as all components
d6097023	421	* of the path to the file must be owned by either the owner of
1ddf764b	422	* of the file or root and no directories must be group or world writable.
c8445989	423	*
	424	* XXX Should any specific check be done for sym links ?
	425	*
	426	* Takes an open file descriptor, the file name, a uid and and
	427	* error buffer plus max size as arguments.
	428	*
	429	* Returns 0 on success and -1 on failure
	430	*/
	431	int
6978866a	432	secure_filename(FILE f, const char file, struct passwd *pw,
6978866a	433	char *err, size_t errlen)
c8445989	434	{
6978866a	435	uid_t uid = pw->pw_uid;
76fbdd47	436	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
c8445989	437	char *cp;
f6f02456	438	int comparehome = 0;
c8445989	439	struct stat st;
	440
	441	if (realpath(file, buf) == NULL) {
	442	snprintf(err, errlen, "realpath %s failed: %s", file,
	443	strerror(errno));
	444	return -1;
	445	}
f6f02456	446	if (realpath(pw->pw_dir, homedir) != NULL)
f6f02456	447	comparehome = 1;
c8445989	448
	449	/* check the open file to avoid races */
	450	if (fstat(fileno(f), &st) < 0 \|\|
	451	(st.st_uid != 0 && st.st_uid != uid) \|\|
	452	(st.st_mode & 022) != 0) {
	453	snprintf(err, errlen, "bad ownership or modes for file %s",
	454	buf);
	455	return -1;
	456	}
	457
	458	/* for each component of the canonical path, walking upwards */
	459	for (;;) {
	460	if ((cp = dirname(buf)) == NULL) {
	461	snprintf(err, errlen, "dirname() failed");
	462	return -1;
	463	}
	464	strlcpy(buf, cp, sizeof(buf));
	465
	466	debug3("secure_filename: checking '%s'", buf);
	467	if (stat(buf, &st) < 0 \|\|
	468	(st.st_uid != 0 && st.st_uid != uid) \|\|
	469	(st.st_mode & 022) != 0) {
184eed6a	470	snprintf(err, errlen,
c8445989	471	"bad ownership or modes for directory %s", buf);
	472	return -1;
	473	}
	474
afd501f9	475	/* If are passed the homedir then we can stop */
f6f02456	476	if (comparehome && strcmp(homedir, buf) == 0) {
afd501f9	477	debug3("secure_filename: terminating check at '%s'",
	478	buf);
	479	break;
	480	}
c8445989	481	/*
	482	* dirname should always complete with a "/" path,
	483	* but we can be paranoid and check for "." too
	484	*/
	485	if ((strcmp("/", buf) == 0) \|\| (strcmp(".", buf) == 0))
	486	break;
	487	}
	488	return 0;
	489	}
443fa1cd	490
	491	struct passwd *
	492	getpwnamallow(const char *user)
	493	{
1836f69f	494	#ifdef HAVE_LOGIN_CAP
	495	extern login_cap_t *lc;
	496	#ifdef BSD_AUTH
	497	auth_session_t *as;
	498	#endif
	499	#endif
443fa1cd	500	struct passwd *pw;
	501
	502	pw = getpwnam(user);
c2802d92	503	if (pw == NULL) {
227a6a97	504	logit("Invalid user %.100s from %.100s",
c2802d92	505	user, get_remote_ipaddr());
73d9dad3	506	#ifdef CUSTOM_FAILED_LOGIN
575e336f	507	record_failed_login(user,
575e336f	508	get_canonical_hostname(options.use_dns), "ssh");
819d3f09	509	#endif
6039eeef	510	#ifdef SSH_AUDIT_EVENTS
	511	audit_event(SSH_INVALID_USER);
	512	#endif /* SSH_AUDIT_EVENTS */
c2802d92	513	return (NULL);
	514	}
	515	if (!allowed_user(pw))
1836f69f	516	return (NULL);
	517	#ifdef HAVE_LOGIN_CAP
	518	if ((lc = login_getclass(pw->pw_class)) == NULL) {
	519	debug("unable to get login class: %s", user);
	520	return (NULL);
	521	}
	522	#ifdef BSD_AUTH
	523	if ((as = auth_open()) == NULL \|\| auth_setpwd(as, pw) != 0 \|\|
65721f9c	524	auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
1836f69f	525	debug("Approval failure for %s", user);
443fa1cd	526	pw = NULL;
1836f69f	527	}
	528	if (as != NULL)
	529	auth_close(as);
	530	#endif
	531	#endif
06bea668	532	if (pw != NULL)
	533	return (pwcopy(pw));
	534	return (NULL);
443fa1cd	535	}
01dafcb5	536
	537	void
	538	auth_debug_add(const char *fmt,...)
	539	{
	540	char buf[1024];
	541	va_list args;
	542
	543	if (!auth_debug_init)
	544	return;
	545
	546	va_start(args, fmt);
	547	vsnprintf(buf, sizeof(buf), fmt, args);
	548	va_end(args);
	549	buffer_put_cstring(&auth_debug, buf);
	550	}
	551
	552	void
	553	auth_debug_send(void)
	554	{
	555	char *msg;
	556
	557	if (!auth_debug_init)
	558	return;
	559	while (buffer_len(&auth_debug)) {
	560	msg = buffer_get_string(&auth_debug, NULL);
	561	packet_send_debug("%s", msg);
	562	xfree(msg);
	563	}
	564	}
	565
	566	void
	567	auth_debug_reset(void)
	568	{
	569	if (auth_debug_init)
	570	buffer_clear(&auth_debug);
	571	else {
	572	buffer_init(&auth_debug);
	573	auth_debug_init = 1;
	574	}
	575	}
96d0bf74	576
	577	struct passwd *
	578	fakepw(void)
	579	{
	580	static struct passwd fake;
	581
	582	memset(&fake, 0, sizeof(fake));
	583	fake.pw_name = "NOUSER";
	584	fake.pw_passwd =
b6453d99	585	"$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
96d0bf74	586	fake.pw_gecos = "NOUSER";
f6be21a0	587	fake.pw_uid = (uid_t)-1;
f6be21a0	588	fake.pw_gid = (gid_t)-1;
96d0bf74	589	#ifdef HAVE_PW_CLASS_IN_PASSWD
	590	fake.pw_class = "";
	591	#endif
	592	fake.pw_dir = "/nonexist";
	593	fake.pw_shell = "/nonexist";
	594
	595	return (&fake);
	596	}