[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 1.61 2006/02/08 12:15:27 stevesk Exp $");

#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 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;

	/* 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"
a75f5360	26	RCSID("$OpenBSD: auth.c,v 1.61 2006/02/08 12:15:27 stevesk Exp $");
7368a6c8	27
a75f5360	28	#ifdef HAVE_PATHS_H
	29	# include <paths.h>
	30	#endif
c1ef8333	31	#ifdef HAVE_LOGIN_H
	32	#include <login.h>
	33	#endif
f14ca4a4	34	#ifdef USE_SHADOW
4cb5ffa0	35	#include <shadow.h>
f14ca4a4	36	#endif
7368a6c8	37
b4d02860	38	#ifdef HAVE_LIBGEN_H
c8445989	39	#include <libgen.h>
b4d02860	40	#endif
c8445989	41
42f11eb2	42	#include "xmalloc.h"
	43	#include "match.h"
	44	#include "groupaccess.h"
	45	#include "log.h"
	46	#include "servconf.h"
e78a59f5	47	#include "auth.h"
59c97189	48	#include "auth-options.h"
42f11eb2	49	#include "canohost.h"
c8445989	50	#include "buffer.h"
c8445989	51	#include "bufaux.h"
d0c8ca5c	52	#include "uidswap.h"
5f1f36b5	53	#include "misc.h"
01dafcb5	54	#include "bufaux.h"
01dafcb5	55	#include "packet.h"
575e336f	56	#include "loginrec.h"
c00e4d75	57	#include "monitor_wrap.h"
e78a59f5	58
7368a6c8	59	/* import */
7368a6c8	60	extern ServerOptions options;
bc7dfc06	61	extern Buffer loginmsg;
7368a6c8	62
01dafcb5	63	/* Debugging messages */
	64	Buffer auth_debug;
	65	int auth_debug_init;
	66
7368a6c8	67	/*
c6a69271	68	* Check if the user is allowed to log in via ssh. If user is listed
	69	* in DenyUsers or one of user's groups is listed in DenyGroups, false
	70	* will be returned. If AllowUsers isn't empty and user isn't listed
	71	* there, or if AllowGroups isn't empty and one of user's groups isn't
	72	* listed there, false will be returned.
7368a6c8	73	* If the user's shell is not executable, false will be returned.
6ae2364d	74	* Otherwise true is returned.
7368a6c8	75	*/
a306f2dd	76	int
7368a6c8	77	allowed_user(struct passwd * pw)
	78	{
	79	struct stat st;
da67ae18	80	const char hostname = NULL, ipaddr = NULL, *passwd = NULL;
614dee3a	81	char *shell;
2ceb8101	82	u_int i;
f14ca4a4	83	#ifdef USE_SHADOW
3e6e3da0	84	struct spwd *spw = NULL;
e2ef2342	85	#endif
7368a6c8	86
7368a6c8	87	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
c6a69271	88	if (!pw \|\| !pw->pw_name)
7368a6c8	89	return 0;
7368a6c8	90
f14ca4a4	91	#ifdef USE_SHADOW
3e6e3da0	92	if (!options.use_pam)
	93	spw = getspnam(pw->pw_name);
	94	#ifdef HAS_SHADOW_EXPIRE
f14ca4a4	95	if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
f14ca4a4	96	return 0;
3e6e3da0	97	#endif /* HAS_SHADOW_EXPIRE */
f14ca4a4	98	#endif /* USE_SHADOW */
3e6e3da0	99
aff51935	100	/* grab passwd field for locked account check */
f14ca4a4	101	#ifdef USE_SHADOW
3e6e3da0	102	if (spw != NULL)
26d07095	103	#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
4c653d8e	104	passwd = get_iaf_password(pw);
4c653d8e	105	#else
3e6e3da0	106	passwd = spw->sp_pwdp;
26d07095	107	#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
3e6e3da0	108	#else
3e6e3da0	109	passwd = pw->pw_passwd;
b57c8e20	110	#endif
b57c8e20	111
aff51935	112	/* check for locked account */
da67ae18	113	if (!options.use_pam && passwd && *passwd) {
3e6e3da0	114	int locked = 0;
	115
	116	#ifdef LOCKED_PASSWD_STRING
	117	if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
	118	locked = 1;
	119	#endif
	120	#ifdef LOCKED_PASSWD_PREFIX
	121	if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
	122	strlen(LOCKED_PASSWD_PREFIX)) == 0)
	123	locked = 1;
	124	#endif
	125	#ifdef LOCKED_PASSWD_SUBSTR
	126	if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
	127	locked = 1;
	128	#endif
26d07095	129	#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
	130	free(passwd);
	131	#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
3e6e3da0	132	if (locked) {
	133	logit("User %.100s not allowed because account is locked",
	134	pw->pw_name);
	135	return 0;
	136	}
	137	}
	138
301e9b01	139	/*
	140	* Get the shell from the password data. An empty shell field is
	141	* legal, and means /bin/sh.
	142	*/
	143	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
	144
	145	/* deny if shell does not exists or is not executable */
b334badd	146	if (stat(shell, &st) != 0) {
bbe88b6d	147	logit("User %.100s not allowed because shell %.100s does not exist",
b334badd	148	pw->pw_name, shell);
7368a6c8	149	return 0;
b334badd	150	}
c390a3c8	151	if (S_ISREG(st.st_mode) == 0 \|\|
c390a3c8	152	(st.st_mode & (S_IXOTH\|S_IXUSR\|S_IXGRP)) == 0) {
bbe88b6d	153	logit("User %.100s not allowed because shell %.100s is not executable",
b334badd	154	pw->pw_name, shell);
7368a6c8	155	return 0;
b334badd	156	}
7368a6c8	157
2dcbac07	158	if (options.num_deny_users > 0 \|\| options.num_allow_users > 0 \|\|
2dcbac07	159	options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
c5a7d788	160	hostname = get_canonical_hostname(options.use_dns);
6805fc56	161	ipaddr = get_remote_ipaddr();
	162	}
	163
7368a6c8	164	/* Return false if user is listed in DenyUsers */
7368a6c8	165	if (options.num_deny_users > 0) {
7368a6c8	166	for (i = 0; i < options.num_deny_users; i++)
762715ce	167	if (match_user(pw->pw_name, hostname, ipaddr,
b334badd	168	options.deny_users[i])) {
31de8b2b	169	logit("User %.100s from %.100s not allowed "
	170	"because listed in DenyUsers",
	171	pw->pw_name, hostname);
7368a6c8	172	return 0;
b334badd	173	}
7368a6c8	174	}
	175	/* Return false if AllowUsers isn't empty and user isn't listed there */
	176	if (options.num_allow_users > 0) {
7368a6c8	177	for (i = 0; i < options.num_allow_users; i++)
762715ce	178	if (match_user(pw->pw_name, hostname, ipaddr,
80f8f24f	179	options.allow_users[i]))
7368a6c8	180	break;
7368a6c8	181	/* i < options.num_allow_users iff we break for loop */
b334badd	182	if (i >= options.num_allow_users) {
31de8b2b	183	logit("User %.100s from %.100s not allowed because "
31de8b2b	184	"not listed in AllowUsers", pw->pw_name, hostname);
7368a6c8	185	return 0;
b334badd	186	}
7368a6c8	187	}
7368a6c8	188	if (options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
c6a69271	189	/* Get the user's group access list (primary and supplementary) */
b334badd	190	if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
31de8b2b	191	logit("User %.100s from %.100s not allowed because "
31de8b2b	192	"not in any group", pw->pw_name, hostname);
7368a6c8	193	return 0;
b334badd	194	}
7368a6c8	195
c6a69271	196	/* Return false if one of user's groups is listed in DenyGroups */
	197	if (options.num_deny_groups > 0)
	198	if (ga_match(options.deny_groups,
	199	options.num_deny_groups)) {
	200	ga_free();
31de8b2b	201	logit("User %.100s from %.100s not allowed "
	202	"because a group is listed in DenyGroups",
	203	pw->pw_name, hostname);
7368a6c8	204	return 0;
c6a69271	205	}
7368a6c8	206	/*
c6a69271	207	* Return false if AllowGroups isn't empty and one of user's groups
7368a6c8	208	* isn't listed there
7368a6c8	209	*/
c6a69271	210	if (options.num_allow_groups > 0)
	211	if (!ga_match(options.allow_groups,
	212	options.num_allow_groups)) {
	213	ga_free();
31de8b2b	214	logit("User %.100s from %.100s not allowed "
	215	"because none of user's groups are listed "
	216	"in AllowGroups", pw->pw_name, hostname);
7368a6c8	217	return 0;
c6a69271	218	}
c6a69271	219	ga_free();
7368a6c8	220	}
7368a6c8	221
bc5c2025	222	#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
5ccf88cb	223	if (!sys_auth_allowed_user(pw, &loginmsg))
bc5c2025	224	return 0;
bc5c2025	225	#endif
7368a6c8	226
	227	/* We found no reason not to let this user try to log on... */
	228	return 1;
	229	}
59c97189	230
59c97189	231	void
	232	auth_log(Authctxt authctxt, int authenticated, char method, char *info)
	233	{
	234	void (authlog) (const char fmt,...) = verbose;
	235	char *authmsg;
	236
	237	/* Raise logging level */
	238	if (authenticated == 1 \|\|
	239	!authctxt->valid \|\|
af4bd935	240	authctxt->failures >= options.max_authtries / 2 \|\|
59c97189	241	strcmp(method, "password") == 0)
a3568201	242	authlog = logit;
59c97189	243
	244	if (authctxt->postponed)
	245	authmsg = "Postponed";
	246	else
	247	authmsg = authenticated ? "Accepted" : "Failed";
	248
	249	authlog("%s %s for %s%.100s from %.200s port %d%s",
	250	authmsg,
	251	method,
d77347cc	252	authctxt->valid ? "" : "invalid user ",
fad3754c	253	authctxt->user,
59c97189	254	get_remote_ipaddr(),
	255	get_remote_port(),
	256	info);
56fd97d7	257
73d9dad3	258	#ifdef CUSTOM_FAILED_LOGIN
b6610e8f	259	if (authenticated == 0 && !authctxt->postponed &&
b6610e8f	260	(strcmp(method, "password") == 0 \|\|
6af6e631	261	strncmp(method, "keyboard-interactive", 20) == 0 \|\|
6af6e631	262	strcmp(method, "challenge-response") == 0))
575e336f	263	record_failed_login(authctxt->user,
575e336f	264	get_canonical_hostname(options.use_dns), "ssh");
73d9dad3	265	#endif
6039eeef	266	#ifdef SSH_AUDIT_EVENTS
c00e4d75	267	if (authenticated == 0 && !authctxt->postponed) {
	268	ssh_audit_event_t event;
	269
	270	debug3("audit failed auth attempt, method %s euid %d",
	271	method, (int)geteuid());
	272	/*
	273	* Because the auth loop is used in both monitor and slave,
	274	* we must be careful to send each event only once and with
	275	* enough privs to write the event.
	276	*/
	277	event = audit_classify_auth(method);
	278	switch(event) {
6039eeef	279	case SSH_AUTH_FAIL_NONE:
	280	case SSH_AUTH_FAIL_PASSWD:
	281	case SSH_AUTH_FAIL_KBDINT:
c00e4d75	282	if (geteuid() == 0)
	283	audit_event(event);
	284	break;
6039eeef	285	case SSH_AUTH_FAIL_PUBKEY:
	286	case SSH_AUTH_FAIL_HOSTBASED:
	287	case SSH_AUTH_FAIL_GSSAPI:
c00e4d75	288	/*
	289	* This is required to handle the case where privsep
	290	* is enabled but it's root logging in, since
	291	* use_privsep won't be cleared until after a
	292	* successful login.
	293	*/
	294	if (geteuid() == 0)
	295	audit_event(event);
	296	else
	297	PRIVSEP(audit_event(event));
	298	break;
	299	default:
	300	error("unknown authentication audit event %d", event);
	301	}
	302	}
	303	#endif
59c97189	304	}
	305
	306	/*
15853e93	307	* Check whether root logins are disallowed.
59c97189	308	*/
59c97189	309	int
15853e93	310	auth_root_allowed(char *method)
59c97189	311	{
15853e93	312	switch (options.permit_root_login) {
15853e93	313	case PERMIT_YES:
59c97189	314	return 1;
15853e93	315	break;
	316	case PERMIT_NO_PASSWD:
	317	if (strcmp(method, "password") != 0)
	318	return 1;
	319	break;
	320	case PERMIT_FORCED_ONLY:
	321	if (forced_command) {
bbe88b6d	322	logit("Root login accepted for forced command.");
15853e93	323	return 1;
	324	}
	325	break;
59c97189	326	}
bbe88b6d	327	logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
15853e93	328	return 0;
59c97189	329	}
c8445989	330
	331
	332	/*
	333	* Given a template and a passwd structure, build a filename
	334	* by substituting % tokenised options. Currently, %% becomes '%',
	335	* %h becomes the home directory and %u the username.
	336	*
	337	* This returns a buffer allocated by xmalloc.
	338	*/
a980cbd7	339	static char *
a980cbd7	340	expand_authorized_keys(const char filename, struct passwd pw)
c8445989	341	{
a980cbd7	342	char file, ret;
c8445989	343
a980cbd7	344	file = percent_expand(filename, "h", pw->pw_dir,
a980cbd7	345	"u", pw->pw_name, (char *)NULL);
c8445989	346
	347	/*
	348	* Ensure that filename starts anchored. If not, be backward
	349	* compatible and prepend the '%h/'
	350	*/
a980cbd7	351	if (*file == '/')
	352	return (file);
	353
	354	ret = xmalloc(MAXPATHLEN);
	355	if (strlcpy(ret, pw->pw_dir, MAXPATHLEN) >= MAXPATHLEN \|\|
	356	strlcat(ret, "/", MAXPATHLEN) >= MAXPATHLEN \|\|
	357	strlcat(ret, file, MAXPATHLEN) >= MAXPATHLEN)
	358	fatal("expand_authorized_keys: path too long");
c8445989	359
a980cbd7	360	xfree(file);
a980cbd7	361	return (ret);
c8445989	362	}
	363
	364	char *
	365	authorized_keys_file(struct passwd *pw)
	366	{
a980cbd7	367	return expand_authorized_keys(options.authorized_keys_file, pw);
c8445989	368	}
	369
	370	char *
	371	authorized_keys_file2(struct passwd *pw)
	372	{
a980cbd7	373	return expand_authorized_keys(options.authorized_keys_file2, pw);
c8445989	374	}
c8445989	375
d0c8ca5c	376	/* return ok if key exists in sysfile or userfile */
	377	HostStatus
	378	check_key_in_hostfiles(struct passwd pw, Key key, const char *host,
	379	const char sysfile, const char userfile)
	380	{
	381	Key *found;
	382	char *user_hostfile;
	383	struct stat st;
17a3011c	384	HostStatus host_status;
d0c8ca5c	385
	386	/* Check if we know the host and its host key. */
	387	found = key_new(key->type);
	388	host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
	389
	390	if (host_status != HOST_OK && userfile != NULL) {
	391	user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
	392	if (options.strict_modes &&
	393	(stat(user_hostfile, &st) == 0) &&
	394	((st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
184eed6a	395	(st.st_mode & 022) != 0)) {
bbe88b6d	396	logit("Authentication refused for %.100s: "
d0c8ca5c	397	"bad owner or modes for %.200s",
	398	pw->pw_name, user_hostfile);
	399	} else {
	400	temporarily_use_uid(pw);
	401	host_status = check_host_in_hostfile(user_hostfile,
	402	host, key, found, NULL);
	403	restore_uid();
	404	}
	405	xfree(user_hostfile);
	406	}
	407	key_free(found);
	408
	409	debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
	410	"ok" : "not found", host);
	411	return host_status;
	412	}
	413
	414
c8445989	415	/*
c8445989	416	* Check a given file for security. This is defined as all components
d6097023	417	* of the path to the file must be owned by either the owner of
1ddf764b	418	* of the file or root and no directories must be group or world writable.
c8445989	419	*
	420	* XXX Should any specific check be done for sym links ?
	421	*
	422	* Takes an open file descriptor, the file name, a uid and and
	423	* error buffer plus max size as arguments.
	424	*
	425	* Returns 0 on success and -1 on failure
	426	*/
	427	int
6978866a	428	secure_filename(FILE f, const char file, struct passwd *pw,
6978866a	429	char *err, size_t errlen)
c8445989	430	{
6978866a	431	uid_t uid = pw->pw_uid;
76fbdd47	432	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
c8445989	433	char *cp;
f6f02456	434	int comparehome = 0;
c8445989	435	struct stat st;
	436
	437	if (realpath(file, buf) == NULL) {
	438	snprintf(err, errlen, "realpath %s failed: %s", file,
	439	strerror(errno));
	440	return -1;
	441	}
f6f02456	442	if (realpath(pw->pw_dir, homedir) != NULL)
f6f02456	443	comparehome = 1;
c8445989	444
	445	/* check the open file to avoid races */
	446	if (fstat(fileno(f), &st) < 0 \|\|
	447	(st.st_uid != 0 && st.st_uid != uid) \|\|
	448	(st.st_mode & 022) != 0) {
	449	snprintf(err, errlen, "bad ownership or modes for file %s",
	450	buf);
	451	return -1;
	452	}
	453
	454	/* for each component of the canonical path, walking upwards */
	455	for (;;) {
	456	if ((cp = dirname(buf)) == NULL) {
	457	snprintf(err, errlen, "dirname() failed");
	458	return -1;
	459	}
	460	strlcpy(buf, cp, sizeof(buf));
	461
	462	debug3("secure_filename: checking '%s'", buf);
	463	if (stat(buf, &st) < 0 \|\|
	464	(st.st_uid != 0 && st.st_uid != uid) \|\|
	465	(st.st_mode & 022) != 0) {
184eed6a	466	snprintf(err, errlen,
c8445989	467	"bad ownership or modes for directory %s", buf);
	468	return -1;
	469	}
	470
afd501f9	471	/* If are passed the homedir then we can stop */
f6f02456	472	if (comparehome && strcmp(homedir, buf) == 0) {
afd501f9	473	debug3("secure_filename: terminating check at '%s'",
	474	buf);
	475	break;
	476	}
c8445989	477	/*
	478	* dirname should always complete with a "/" path,
	479	* but we can be paranoid and check for "." too
	480	*/
	481	if ((strcmp("/", buf) == 0) \|\| (strcmp(".", buf) == 0))
	482	break;
	483	}
	484	return 0;
	485	}
443fa1cd	486
	487	struct passwd *
	488	getpwnamallow(const char *user)
	489	{
1836f69f	490	#ifdef HAVE_LOGIN_CAP
	491	extern login_cap_t *lc;
	492	#ifdef BSD_AUTH
	493	auth_session_t *as;
	494	#endif
	495	#endif
443fa1cd	496	struct passwd *pw;
	497
	498	pw = getpwnam(user);
c2802d92	499	if (pw == NULL) {
227a6a97	500	logit("Invalid user %.100s from %.100s",
c2802d92	501	user, get_remote_ipaddr());
73d9dad3	502	#ifdef CUSTOM_FAILED_LOGIN
575e336f	503	record_failed_login(user,
575e336f	504	get_canonical_hostname(options.use_dns), "ssh");
819d3f09	505	#endif
6039eeef	506	#ifdef SSH_AUDIT_EVENTS
	507	audit_event(SSH_INVALID_USER);
	508	#endif /* SSH_AUDIT_EVENTS */
c2802d92	509	return (NULL);
	510	}
	511	if (!allowed_user(pw))
1836f69f	512	return (NULL);
	513	#ifdef HAVE_LOGIN_CAP
	514	if ((lc = login_getclass(pw->pw_class)) == NULL) {
	515	debug("unable to get login class: %s", user);
	516	return (NULL);
	517	}
	518	#ifdef BSD_AUTH
	519	if ((as = auth_open()) == NULL \|\| auth_setpwd(as, pw) != 0 \|\|
65721f9c	520	auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
1836f69f	521	debug("Approval failure for %s", user);
443fa1cd	522	pw = NULL;
1836f69f	523	}
	524	if (as != NULL)
	525	auth_close(as);
	526	#endif
	527	#endif
06bea668	528	if (pw != NULL)
	529	return (pwcopy(pw));
	530	return (NULL);
443fa1cd	531	}
01dafcb5	532
	533	void
	534	auth_debug_add(const char *fmt,...)
	535	{
	536	char buf[1024];
	537	va_list args;
	538
	539	if (!auth_debug_init)
	540	return;
	541
	542	va_start(args, fmt);
	543	vsnprintf(buf, sizeof(buf), fmt, args);
	544	va_end(args);
	545	buffer_put_cstring(&auth_debug, buf);
	546	}
	547
	548	void
	549	auth_debug_send(void)
	550	{
	551	char *msg;
	552
	553	if (!auth_debug_init)
	554	return;
	555	while (buffer_len(&auth_debug)) {
	556	msg = buffer_get_string(&auth_debug, NULL);
	557	packet_send_debug("%s", msg);
	558	xfree(msg);
	559	}
	560	}
	561
	562	void
	563	auth_debug_reset(void)
	564	{
	565	if (auth_debug_init)
	566	buffer_clear(&auth_debug);
	567	else {
	568	buffer_init(&auth_debug);
	569	auth_debug_init = 1;
	570	}
	571	}
96d0bf74	572
	573	struct passwd *
	574	fakepw(void)
	575	{
	576	static struct passwd fake;
	577
	578	memset(&fake, 0, sizeof(fake));
	579	fake.pw_name = "NOUSER";
	580	fake.pw_passwd =
b6453d99	581	"$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
96d0bf74	582	fake.pw_gecos = "NOUSER";
f6be21a0	583	fake.pw_uid = (uid_t)-1;
f6be21a0	584	fake.pw_gid = (gid_t)-1;
96d0bf74	585	#ifdef HAVE_PW_CLASS_IN_PASSWD
	586	fake.pw_class = "";
	587	#endif
	588	fake.pw_dir = "/nonexist";
	589	fake.pw_shell = "/nonexist";
	590
	591	return (&fake);
	592	}