[openssh.git] / auth.c

/* $OpenBSD: auth.c,v 1.75 2006/08/03 03:34:41 deraadt Exp $ */
/*
 * Copyright (c) 2000 Markus Friedl.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "includes.h"

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/param.h>

#include <netinet/in.h>

#include <errno.h>
#ifdef HAVE_PATHS_H
# include <paths.h>
#endif
#include <pwd.h>
#ifdef HAVE_LOGIN_H
#include <login.h>
#endif
#ifdef USE_SHADOW
#include <shadow.h>
#endif
#ifdef HAVE_LIBGEN_H
#include <libgen.h>
#endif
#include <stdarg.h>
#include <stdio.h>
#include <string.h>

#include "xmalloc.h"
#include "match.h"
#include "groupaccess.h"
#include "log.h"
#include "buffer.h"
#include "servconf.h"
#include "key.h"
#include "hostfile.h"
#include "auth.h"
#include "auth-options.h"
#include "canohost.h"
#include "uidswap.h"
#include "misc.h"
#include "packet.h"
#include "loginrec.h"
#ifdef GSSAPI
#include "ssh-gss.h"
#endif
#include "monitor_wrap.h"

/* import */
extern ServerOptions options;
extern int use_privsep;
extern Buffer loginmsg;

/* Debugging messages */
Buffer auth_debug;
int auth_debug_init;

/*
 * Check if the user is allowed to log in via ssh. If user is listed
 * in DenyUsers or one of user's groups is listed in DenyGroups, false
 * will be returned. If AllowUsers isn't empty and user isn't listed
 * there, or if AllowGroups isn't empty and one of user's groups isn't
 * listed there, false will be returned.
 * If the user's shell is not executable, false will be returned.
 * Otherwise true is returned.
 */
int
allowed_user(struct passwd * pw)
{
	struct stat st;
	const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
	char *shell;
	u_int i;
#ifdef USE_SHADOW
	struct spwd *spw = NULL;
#endif

	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
	if (!pw || !pw->pw_name)
		return 0;

#ifdef USE_SHADOW
	if (!options.use_pam)
		spw = getspnam(pw->pw_name);
#ifdef HAS_SHADOW_EXPIRE
	if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
		return 0;
#endif /* HAS_SHADOW_EXPIRE */
#endif /* USE_SHADOW */

	/* grab passwd field for locked account check */
#ifdef USE_SHADOW
	if (spw != NULL)
#if defined(HAVE_LIBIAF)  &&  !defined(BROKEN_LIBIAF)
		passwd = get_iaf_password(pw);
#else
		passwd = spw->sp_pwdp;
#endif /* HAVE_LIBIAF  && !BROKEN_LIBIAF */
#else
	passwd = pw->pw_passwd;
#endif

	/* check for locked account */
	if (!options.use_pam && passwd && *passwd) {
		int locked = 0;

#ifdef LOCKED_PASSWD_STRING
		if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
			 locked = 1;
#endif
#ifdef LOCKED_PASSWD_PREFIX
		if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
		    strlen(LOCKED_PASSWD_PREFIX)) == 0)
			 locked = 1;
#endif
#ifdef LOCKED_PASSWD_SUBSTR
		if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
			locked = 1;
#endif
#if defined(HAVE_LIBIAF)  &&  !defined(BROKEN_LIBIAF)
		free(passwd);
#endif /* HAVE_LIBIAF  && !BROKEN_LIBIAF */
		if (locked) {
			logit("User %.100s not allowed because account is locked",
			    pw->pw_name);
			return 0;
		}
	}

	/*
	 * Get the shell from the password data.  An empty shell field is
	 * legal, and means /bin/sh.
	 */
	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;

	/* deny if shell does not exists or is not executable */
	if (stat(shell, &st) != 0) {
		logit("User %.100s not allowed because shell %.100s does not exist",
		    pw->pw_name, shell);
		return 0;
	}
	if (S_ISREG(st.st_mode) == 0 ||
	    (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
		logit("User %.100s not allowed because shell %.100s is not executable",
		    pw->pw_name, shell);
		return 0;
	}

	if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
	    options.num_deny_groups > 0 || options.num_allow_groups > 0) {
		hostname = get_canonical_hostname(options.use_dns);
		ipaddr = get_remote_ipaddr();
	}

	/* Return false if user is listed in DenyUsers */
	if (options.num_deny_users > 0) {
		for (i = 0; i < options.num_deny_users; i++)
			if (match_user(pw->pw_name, hostname, ipaddr,
			    options.deny_users[i])) {
				logit("User %.100s from %.100s not allowed "
				    "because listed in DenyUsers",
				    pw->pw_name, hostname);
				return 0;
			}
	}
	/* Return false if AllowUsers isn't empty and user isn't listed there */
	if (options.num_allow_users > 0) {
		for (i = 0; i < options.num_allow_users; i++)
			if (match_user(pw->pw_name, hostname, ipaddr,
			    options.allow_users[i]))
				break;
		/* i < options.num_allow_users iff we break for loop */
		if (i >= options.num_allow_users) {
			logit("User %.100s from %.100s not allowed because "
			    "not listed in AllowUsers", pw->pw_name, hostname);
			return 0;
		}
	}
	if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
		/* Get the user's group access list (primary and supplementary) */
		if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
			logit("User %.100s from %.100s not allowed because "
			    "not in any group", pw->pw_name, hostname);
			return 0;
		}

		/* Return false if one of user's groups is listed in DenyGroups */
		if (options.num_deny_groups > 0)
			if (ga_match(options.deny_groups,
			    options.num_deny_groups)) {
				ga_free();
				logit("User %.100s from %.100s not allowed "
				    "because a group is listed in DenyGroups",
				    pw->pw_name, hostname);
				return 0;
			}
		/*
		 * Return false if AllowGroups isn't empty and one of user's groups
		 * isn't listed there
		 */
		if (options.num_allow_groups > 0)
			if (!ga_match(options.allow_groups,
			    options.num_allow_groups)) {
				ga_free();
				logit("User %.100s from %.100s not allowed "
				    "because none of user's groups are listed "
				    "in AllowGroups", pw->pw_name, hostname);
				return 0;
			}
		ga_free();
	}

#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
	if (!sys_auth_allowed_user(pw, &loginmsg))
		return 0;
#endif

	/* We found no reason not to let this user try to log on... */
	return 1;
}

void
auth_log(Authctxt *authctxt, int authenticated, char *method, char *info)
{
	void (*authlog) (const char *fmt,...) = verbose;
	char *authmsg;

	if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
		return;

	/* Raise logging level */
	if (authenticated == 1 ||
	    !authctxt->valid ||
	    authctxt->failures >= options.max_authtries / 2 ||
	    strcmp(method, "password") == 0)
		authlog = logit;

	if (authctxt->postponed)
		authmsg = "Postponed";
	else
		authmsg = authenticated ? "Accepted" : "Failed";

	authlog("%s %s for %s%.100s from %.200s port %d%s",
	    authmsg,
	    method,
	    authctxt->valid ? "" : "invalid user ",
	    authctxt->user,
	    get_remote_ipaddr(),
	    get_remote_port(),
	    info);

#ifdef CUSTOM_FAILED_LOGIN
	if (authenticated == 0 && !authctxt->postponed &&
	    (strcmp(method, "password") == 0 ||
	    strncmp(method, "keyboard-interactive", 20) == 0 ||
	    strcmp(method, "challenge-response") == 0))
		record_failed_login(authctxt->user,
		    get_canonical_hostname(options.use_dns), "ssh");
#endif
#ifdef SSH_AUDIT_EVENTS
	if (authenticated == 0 && !authctxt->postponed)
		audit_event(audit_classify_auth(method));
#endif
}

/*
 * Check whether root logins are disallowed.
 */
int
auth_root_allowed(char *method)
{
	switch (options.permit_root_login) {
	case PERMIT_YES:
		return 1;
	case PERMIT_NO_PASSWD:
		if (strcmp(method, "password") != 0)
			return 1;
		break;
	case PERMIT_FORCED_ONLY:
		if (forced_command) {
			logit("Root login accepted for forced command.");
			return 1;
		}
		break;
	}
	logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
	return 0;
}


/*
 * Given a template and a passwd structure, build a filename
 * by substituting % tokenised options. Currently, %% becomes '%',
 * %h becomes the home directory and %u the username.
 *
 * This returns a buffer allocated by xmalloc.
 */
static char *
expand_authorized_keys(const char *filename, struct passwd *pw)
{
	char *file, ret[MAXPATHLEN];
	int i;

	file = percent_expand(filename, "h", pw->pw_dir,
	    "u", pw->pw_name, (char *)NULL);

	/*
	 * Ensure that filename starts anchored. If not, be backward
	 * compatible and prepend the '%h/'
	 */
	if (*file == '/')
		return (file);

	i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
	if (i < 0 || (size_t)i >= sizeof(ret))
		fatal("expand_authorized_keys: path too long");
	xfree(file);
	return (xstrdup(ret));
}

char *
authorized_keys_file(struct passwd *pw)
{
	return expand_authorized_keys(options.authorized_keys_file, pw);
}

char *
authorized_keys_file2(struct passwd *pw)
{
	return expand_authorized_keys(options.authorized_keys_file2, pw);
}

/* return ok if key exists in sysfile or userfile */
HostStatus
check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
    const char *sysfile, const char *userfile)
{
	Key *found;
	char *user_hostfile;
	struct stat st;
	HostStatus host_status;

	/* Check if we know the host and its host key. */
	found = key_new(key->type);
	host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);

	if (host_status != HOST_OK && userfile != NULL) {
		user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
		if (options.strict_modes &&
		    (stat(user_hostfile, &st) == 0) &&
		    ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
		    (st.st_mode & 022) != 0)) {
			logit("Authentication refused for %.100s: "
			    "bad owner or modes for %.200s",
			    pw->pw_name, user_hostfile);
		} else {
			temporarily_use_uid(pw);
			host_status = check_host_in_hostfile(user_hostfile,
			    host, key, found, NULL);
			restore_uid();
		}
		xfree(user_hostfile);
	}
	key_free(found);

	debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
	    "ok" : "not found", host);
	return host_status;
}


/*
 * Check a given file for security. This is defined as all components
 * of the path to the file must be owned by either the owner of
 * of the file or root and no directories must be group or world writable.
 *
 * XXX Should any specific check be done for sym links ?
 *
 * Takes an open file descriptor, the file name, a uid and and
 * error buffer plus max size as arguments.
 *
 * Returns 0 on success and -1 on failure
 */
int
secure_filename(FILE *f, const char *file, struct passwd *pw,
    char *err, size_t errlen)
{
	uid_t uid = pw->pw_uid;
	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
	char *cp;
	int comparehome = 0;
	struct stat st;

	if (realpath(file, buf) == NULL) {
		snprintf(err, errlen, "realpath %s failed: %s", file,
		    strerror(errno));
		return -1;
	}
	if (realpath(pw->pw_dir, homedir) != NULL)
		comparehome = 1;

	/* check the open file to avoid races */
	if (fstat(fileno(f), &st) < 0 ||
	    (st.st_uid != 0 && st.st_uid != uid) ||
	    (st.st_mode & 022) != 0) {
		snprintf(err, errlen, "bad ownership or modes for file %s",
		    buf);
		return -1;
	}

	/* for each component of the canonical path, walking upwards */
	for (;;) {
		if ((cp = dirname(buf)) == NULL) {
			snprintf(err, errlen, "dirname() failed");
			return -1;
		}
		strlcpy(buf, cp, sizeof(buf));

		debug3("secure_filename: checking '%s'", buf);
		if (stat(buf, &st) < 0 ||
		    (st.st_uid != 0 && st.st_uid != uid) ||
		    (st.st_mode & 022) != 0) {
			snprintf(err, errlen,
			    "bad ownership or modes for directory %s", buf);
			return -1;
		}

		/* If are passed the homedir then we can stop */
		if (comparehome && strcmp(homedir, buf) == 0) {
			debug3("secure_filename: terminating check at '%s'",
			    buf);
			break;
		}
		/*
		 * dirname should always complete with a "/" path,
		 * but we can be paranoid and check for "." too
		 */
		if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
			break;
	}
	return 0;
}

struct passwd *
getpwnamallow(const char *user)
{
#ifdef HAVE_LOGIN_CAP
	extern login_cap_t *lc;
#ifdef BSD_AUTH
	auth_session_t *as;
#endif
#endif
	struct passwd *pw;

	parse_server_match_config(&options, user,
	    get_canonical_hostname(options.use_dns), get_remote_ipaddr());

	pw = getpwnam(user);
	if (pw == NULL) {
		logit("Invalid user %.100s from %.100s",
		    user, get_remote_ipaddr());
#ifdef CUSTOM_FAILED_LOGIN
		record_failed_login(user,
		    get_canonical_hostname(options.use_dns), "ssh");
#endif
#ifdef SSH_AUDIT_EVENTS
		audit_event(SSH_INVALID_USER);
#endif /* SSH_AUDIT_EVENTS */
		return (NULL);
	}
	if (!allowed_user(pw))
		return (NULL);
#ifdef HAVE_LOGIN_CAP
	if ((lc = login_getclass(pw->pw_class)) == NULL) {
		debug("unable to get login class: %s", user);
		return (NULL);
	}
#ifdef BSD_AUTH
	if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
	    auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
		debug("Approval failure for %s", user);
		pw = NULL;
	}
	if (as != NULL)
		auth_close(as);
#endif
#endif
	if (pw != NULL)
		return (pwcopy(pw));
	return (NULL);
}

void
auth_debug_add(const char *fmt,...)
{
	char buf[1024];
	va_list args;

	if (!auth_debug_init)
		return;

	va_start(args, fmt);
	vsnprintf(buf, sizeof(buf), fmt, args);
	va_end(args);
	buffer_put_cstring(&auth_debug, buf);
}

void
auth_debug_send(void)
{
	char *msg;

	if (!auth_debug_init)
		return;
	while (buffer_len(&auth_debug)) {
		msg = buffer_get_string(&auth_debug, NULL);
		packet_send_debug("%s", msg);
		xfree(msg);
	}
}

void
auth_debug_reset(void)
{
	if (auth_debug_init)
		buffer_clear(&auth_debug);
	else {
		buffer_init(&auth_debug);
		auth_debug_init = 1;
	}
}

struct passwd *
fakepw(void)
{
	static struct passwd fake;

	memset(&fake, 0, sizeof(fake));
	fake.pw_name = "NOUSER";
	fake.pw_passwd =
	    "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
	fake.pw_gecos = "NOUSER";
	fake.pw_uid = (uid_t)-1;
	fake.pw_gid = (gid_t)-1;
#ifdef HAVE_PW_CLASS_IN_PASSWD
	fake.pw_class = "";
#endif
	fake.pw_dir = "/nonexist";
	fake.pw_shell = "/nonexist";

	return (&fake);
}
Commit	Line	Data
31652869	1	/* $OpenBSD: auth.c,v 1.75 2006/08/03 03:34:41 deraadt 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>
536c14e8	30	#include <sys/param.h>
7368a6c8	31
8ad2db2a	32	#include <netinet/in.h>
8ad2db2a	33
028094f4	34	#include <errno.h>
a75f5360	35	#ifdef HAVE_PATHS_H
6f61e0ec	36	# include <paths.h>
a75f5360	37	#endif
b1842393	38	#include <pwd.h>
c1ef8333	39	#ifdef HAVE_LOGIN_H
	40	#include <login.h>
	41	#endif
f14ca4a4	42	#ifdef USE_SHADOW
4cb5ffa0	43	#include <shadow.h>
f14ca4a4	44	#endif
b4d02860	45	#ifdef HAVE_LIBGEN_H
c8445989	46	#include <libgen.h>
b4d02860	47	#endif
4c72fcfd	48	#include <stdarg.h>
cf851879	49	#include <stdio.h>
00146caa	50	#include <string.h>
c8445989	51
42f11eb2	52	#include "xmalloc.h"
	53	#include "match.h"
	54	#include "groupaccess.h"
	55	#include "log.h"
31652869	56	#include "buffer.h"
42f11eb2	57	#include "servconf.h"
31652869	58	#include "key.h"
31652869	59	#include "hostfile.h"
e78a59f5	60	#include "auth.h"
59c97189	61	#include "auth-options.h"
42f11eb2	62	#include "canohost.h"
d0c8ca5c	63	#include "uidswap.h"
5f1f36b5	64	#include "misc.h"
01dafcb5	65	#include "packet.h"
575e336f	66	#include "loginrec.h"
31652869	67	#ifdef GSSAPI
	68	#include "ssh-gss.h"
	69	#endif
c00e4d75	70	#include "monitor_wrap.h"
e78a59f5	71
7368a6c8	72	/* import */
7368a6c8	73	extern ServerOptions options;
c023a130	74	extern int use_privsep;
bc7dfc06	75	extern Buffer loginmsg;
7368a6c8	76
01dafcb5	77	/* Debugging messages */
	78	Buffer auth_debug;
	79	int auth_debug_init;
	80
7368a6c8	81	/*
c6a69271	82	* Check if the user is allowed to log in via ssh. If user is listed
	83	* in DenyUsers or one of user's groups is listed in DenyGroups, false
	84	* will be returned. If AllowUsers isn't empty and user isn't listed
	85	* there, or if AllowGroups isn't empty and one of user's groups isn't
	86	* listed there, false will be returned.
7368a6c8	87	* If the user's shell is not executable, false will be returned.
6ae2364d	88	* Otherwise true is returned.
7368a6c8	89	*/
a306f2dd	90	int
7368a6c8	91	allowed_user(struct passwd * pw)
	92	{
	93	struct stat st;
da67ae18	94	const char hostname = NULL, ipaddr = NULL, *passwd = NULL;
614dee3a	95	char *shell;
2ceb8101	96	u_int i;
f14ca4a4	97	#ifdef USE_SHADOW
3e6e3da0	98	struct spwd *spw = NULL;
e2ef2342	99	#endif
7368a6c8	100
7368a6c8	101	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
c6a69271	102	if (!pw \|\| !pw->pw_name)
7368a6c8	103	return 0;
7368a6c8	104
f14ca4a4	105	#ifdef USE_SHADOW
3e6e3da0	106	if (!options.use_pam)
	107	spw = getspnam(pw->pw_name);
	108	#ifdef HAS_SHADOW_EXPIRE
f14ca4a4	109	if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
f14ca4a4	110	return 0;
3e6e3da0	111	#endif /* HAS_SHADOW_EXPIRE */
f14ca4a4	112	#endif /* USE_SHADOW */
3e6e3da0	113
aff51935	114	/* grab passwd field for locked account check */
f14ca4a4	115	#ifdef USE_SHADOW
3e6e3da0	116	if (spw != NULL)
26d07095	117	#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
4c653d8e	118	passwd = get_iaf_password(pw);
4c653d8e	119	#else
3e6e3da0	120	passwd = spw->sp_pwdp;
26d07095	121	#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
3e6e3da0	122	#else
3e6e3da0	123	passwd = pw->pw_passwd;
b57c8e20	124	#endif
b57c8e20	125
aff51935	126	/* check for locked account */
da67ae18	127	if (!options.use_pam && passwd && *passwd) {
3e6e3da0	128	int locked = 0;
	129
	130	#ifdef LOCKED_PASSWD_STRING
	131	if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
	132	locked = 1;
	133	#endif
	134	#ifdef LOCKED_PASSWD_PREFIX
	135	if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
	136	strlen(LOCKED_PASSWD_PREFIX)) == 0)
	137	locked = 1;
	138	#endif
	139	#ifdef LOCKED_PASSWD_SUBSTR
	140	if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
	141	locked = 1;
	142	#endif
26d07095	143	#if defined(HAVE_LIBIAF) && !defined(BROKEN_LIBIAF)
	144	free(passwd);
	145	#endif /* HAVE_LIBIAF && !BROKEN_LIBIAF */
3e6e3da0	146	if (locked) {
	147	logit("User %.100s not allowed because account is locked",
	148	pw->pw_name);
	149	return 0;
	150	}
	151	}
	152
301e9b01	153	/*
	154	* Get the shell from the password data. An empty shell field is
	155	* legal, and means /bin/sh.
	156	*/
	157	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
	158
	159	/* deny if shell does not exists or is not executable */
b334badd	160	if (stat(shell, &st) != 0) {
bbe88b6d	161	logit("User %.100s not allowed because shell %.100s does not exist",
b334badd	162	pw->pw_name, shell);
7368a6c8	163	return 0;
b334badd	164	}
c390a3c8	165	if (S_ISREG(st.st_mode) == 0 \|\|
c390a3c8	166	(st.st_mode & (S_IXOTH\|S_IXUSR\|S_IXGRP)) == 0) {
bbe88b6d	167	logit("User %.100s not allowed because shell %.100s is not executable",
b334badd	168	pw->pw_name, shell);
7368a6c8	169	return 0;
b334badd	170	}
7368a6c8	171
2dcbac07	172	if (options.num_deny_users > 0 \|\| options.num_allow_users > 0 \|\|
2dcbac07	173	options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
c5a7d788	174	hostname = get_canonical_hostname(options.use_dns);
6805fc56	175	ipaddr = get_remote_ipaddr();
	176	}
	177
7368a6c8	178	/* Return false if user is listed in DenyUsers */
7368a6c8	179	if (options.num_deny_users > 0) {
7368a6c8	180	for (i = 0; i < options.num_deny_users; i++)
762715ce	181	if (match_user(pw->pw_name, hostname, ipaddr,
b334badd	182	options.deny_users[i])) {
31de8b2b	183	logit("User %.100s from %.100s not allowed "
	184	"because listed in DenyUsers",
	185	pw->pw_name, hostname);
7368a6c8	186	return 0;
b334badd	187	}
7368a6c8	188	}
	189	/* Return false if AllowUsers isn't empty and user isn't listed there */
	190	if (options.num_allow_users > 0) {
7368a6c8	191	for (i = 0; i < options.num_allow_users; i++)
762715ce	192	if (match_user(pw->pw_name, hostname, ipaddr,
80f8f24f	193	options.allow_users[i]))
7368a6c8	194	break;
7368a6c8	195	/* i < options.num_allow_users iff we break for loop */
b334badd	196	if (i >= options.num_allow_users) {
31de8b2b	197	logit("User %.100s from %.100s not allowed because "
31de8b2b	198	"not listed in AllowUsers", pw->pw_name, hostname);
7368a6c8	199	return 0;
b334badd	200	}
7368a6c8	201	}
7368a6c8	202	if (options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
c6a69271	203	/* Get the user's group access list (primary and supplementary) */
b334badd	204	if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
31de8b2b	205	logit("User %.100s from %.100s not allowed because "
31de8b2b	206	"not in any group", pw->pw_name, hostname);
7368a6c8	207	return 0;
b334badd	208	}
7368a6c8	209
c6a69271	210	/* Return false if one of user's groups is listed in DenyGroups */
	211	if (options.num_deny_groups > 0)
	212	if (ga_match(options.deny_groups,
	213	options.num_deny_groups)) {
	214	ga_free();
31de8b2b	215	logit("User %.100s from %.100s not allowed "
	216	"because a group is listed in DenyGroups",
	217	pw->pw_name, hostname);
7368a6c8	218	return 0;
c6a69271	219	}
7368a6c8	220	/*
c6a69271	221	* Return false if AllowGroups isn't empty and one of user's groups
7368a6c8	222	* isn't listed there
7368a6c8	223	*/
c6a69271	224	if (options.num_allow_groups > 0)
	225	if (!ga_match(options.allow_groups,
	226	options.num_allow_groups)) {
	227	ga_free();
31de8b2b	228	logit("User %.100s from %.100s not allowed "
	229	"because none of user's groups are listed "
	230	"in AllowGroups", pw->pw_name, hostname);
7368a6c8	231	return 0;
c6a69271	232	}
c6a69271	233	ga_free();
7368a6c8	234	}
7368a6c8	235
bc5c2025	236	#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
5ccf88cb	237	if (!sys_auth_allowed_user(pw, &loginmsg))
bc5c2025	238	return 0;
bc5c2025	239	#endif
7368a6c8	240
	241	/* We found no reason not to let this user try to log on... */
	242	return 1;
	243	}
59c97189	244
59c97189	245	void
	246	auth_log(Authctxt authctxt, int authenticated, char method, char *info)
	247	{
	248	void (authlog) (const char fmt,...) = verbose;
	249	char *authmsg;
	250
c023a130	251	if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
	252	return;
	253
59c97189	254	/* Raise logging level */
	255	if (authenticated == 1 \|\|
	256	!authctxt->valid \|\|
af4bd935	257	authctxt->failures >= options.max_authtries / 2 \|\|
59c97189	258	strcmp(method, "password") == 0)
a3568201	259	authlog = logit;
59c97189	260
	261	if (authctxt->postponed)
	262	authmsg = "Postponed";
	263	else
	264	authmsg = authenticated ? "Accepted" : "Failed";
	265
	266	authlog("%s %s for %s%.100s from %.200s port %d%s",
	267	authmsg,
	268	method,
d77347cc	269	authctxt->valid ? "" : "invalid user ",
fad3754c	270	authctxt->user,
59c97189	271	get_remote_ipaddr(),
	272	get_remote_port(),
	273	info);
56fd97d7	274
73d9dad3	275	#ifdef CUSTOM_FAILED_LOGIN
b6610e8f	276	if (authenticated == 0 && !authctxt->postponed &&
b6610e8f	277	(strcmp(method, "password") == 0 \|\|
6af6e631	278	strncmp(method, "keyboard-interactive", 20) == 0 \|\|
6af6e631	279	strcmp(method, "challenge-response") == 0))
575e336f	280	record_failed_login(authctxt->user,
575e336f	281	get_canonical_hostname(options.use_dns), "ssh");
73d9dad3	282	#endif
6039eeef	283	#ifdef SSH_AUDIT_EVENTS
2ae7f715	284	if (authenticated == 0 && !authctxt->postponed)
2ae7f715	285	audit_event(audit_classify_auth(method));
c00e4d75	286	#endif
59c97189	287	}
	288
	289	/*
15853e93	290	* Check whether root logins are disallowed.
59c97189	291	*/
59c97189	292	int
15853e93	293	auth_root_allowed(char *method)
59c97189	294	{
15853e93	295	switch (options.permit_root_login) {
15853e93	296	case PERMIT_YES:
59c97189	297	return 1;
15853e93	298	case PERMIT_NO_PASSWD:
	299	if (strcmp(method, "password") != 0)
	300	return 1;
	301	break;
	302	case PERMIT_FORCED_ONLY:
	303	if (forced_command) {
bbe88b6d	304	logit("Root login accepted for forced command.");
15853e93	305	return 1;
	306	}
	307	break;
59c97189	308	}
bbe88b6d	309	logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
15853e93	310	return 0;
59c97189	311	}
c8445989	312
	313
	314	/*
	315	* Given a template and a passwd structure, build a filename
	316	* by substituting % tokenised options. Currently, %% becomes '%',
	317	* %h becomes the home directory and %u the username.
	318	*
	319	* This returns a buffer allocated by xmalloc.
	320	*/
a980cbd7	321	static char *
a980cbd7	322	expand_authorized_keys(const char filename, struct passwd pw)
c8445989	323	{
52e3daed	324	char *file, ret[MAXPATHLEN];
52e3daed	325	int i;
c8445989	326
a980cbd7	327	file = percent_expand(filename, "h", pw->pw_dir,
a980cbd7	328	"u", pw->pw_name, (char *)NULL);
c8445989	329
	330	/*
	331	* Ensure that filename starts anchored. If not, be backward
	332	* compatible and prepend the '%h/'
	333	*/
a980cbd7	334	if (*file == '/')
	335	return (file);
	336
52e3daed	337	i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
52e3daed	338	if (i < 0 \|\| (size_t)i >= sizeof(ret))
a980cbd7	339	fatal("expand_authorized_keys: path too long");
a980cbd7	340	xfree(file);
52e3daed	341	return (xstrdup(ret));
c8445989	342	}
	343
	344	char *
	345	authorized_keys_file(struct passwd *pw)
	346	{
a980cbd7	347	return expand_authorized_keys(options.authorized_keys_file, pw);
c8445989	348	}
	349
	350	char *
	351	authorized_keys_file2(struct passwd *pw)
	352	{
a980cbd7	353	return expand_authorized_keys(options.authorized_keys_file2, pw);
c8445989	354	}
c8445989	355
d0c8ca5c	356	/* return ok if key exists in sysfile or userfile */
	357	HostStatus
	358	check_key_in_hostfiles(struct passwd pw, Key key, const char *host,
	359	const char sysfile, const char userfile)
	360	{
	361	Key *found;
	362	char *user_hostfile;
	363	struct stat st;
17a3011c	364	HostStatus host_status;
d0c8ca5c	365
	366	/* Check if we know the host and its host key. */
	367	found = key_new(key->type);
	368	host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
	369
	370	if (host_status != HOST_OK && userfile != NULL) {
	371	user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
	372	if (options.strict_modes &&
	373	(stat(user_hostfile, &st) == 0) &&
	374	((st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
184eed6a	375	(st.st_mode & 022) != 0)) {
bbe88b6d	376	logit("Authentication refused for %.100s: "
d0c8ca5c	377	"bad owner or modes for %.200s",
	378	pw->pw_name, user_hostfile);
	379	} else {
	380	temporarily_use_uid(pw);
	381	host_status = check_host_in_hostfile(user_hostfile,
	382	host, key, found, NULL);
	383	restore_uid();
	384	}
	385	xfree(user_hostfile);
	386	}
	387	key_free(found);
	388
	389	debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
	390	"ok" : "not found", host);
	391	return host_status;
	392	}
	393
	394
c8445989	395	/*
c8445989	396	* Check a given file for security. This is defined as all components
d6097023	397	* of the path to the file must be owned by either the owner of
1ddf764b	398	* of the file or root and no directories must be group or world writable.
c8445989	399	*
	400	* XXX Should any specific check be done for sym links ?
	401	*
	402	* Takes an open file descriptor, the file name, a uid and and
	403	* error buffer plus max size as arguments.
	404	*
	405	* Returns 0 on success and -1 on failure
	406	*/
	407	int
6978866a	408	secure_filename(FILE f, const char file, struct passwd *pw,
6978866a	409	char *err, size_t errlen)
c8445989	410	{
6978866a	411	uid_t uid = pw->pw_uid;
76fbdd47	412	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
c8445989	413	char *cp;
f6f02456	414	int comparehome = 0;
c8445989	415	struct stat st;
	416
	417	if (realpath(file, buf) == NULL) {
	418	snprintf(err, errlen, "realpath %s failed: %s", file,
	419	strerror(errno));
	420	return -1;
	421	}
f6f02456	422	if (realpath(pw->pw_dir, homedir) != NULL)
f6f02456	423	comparehome = 1;
c8445989	424
	425	/* check the open file to avoid races */
	426	if (fstat(fileno(f), &st) < 0 \|\|
	427	(st.st_uid != 0 && st.st_uid != uid) \|\|
	428	(st.st_mode & 022) != 0) {
	429	snprintf(err, errlen, "bad ownership or modes for file %s",
	430	buf);
	431	return -1;
	432	}
	433
	434	/* for each component of the canonical path, walking upwards */
	435	for (;;) {
	436	if ((cp = dirname(buf)) == NULL) {
	437	snprintf(err, errlen, "dirname() failed");
	438	return -1;
	439	}
	440	strlcpy(buf, cp, sizeof(buf));
	441
	442	debug3("secure_filename: checking '%s'", buf);
	443	if (stat(buf, &st) < 0 \|\|
	444	(st.st_uid != 0 && st.st_uid != uid) \|\|
	445	(st.st_mode & 022) != 0) {
184eed6a	446	snprintf(err, errlen,
c8445989	447	"bad ownership or modes for directory %s", buf);
	448	return -1;
	449	}
	450
afd501f9	451	/* If are passed the homedir then we can stop */
f6f02456	452	if (comparehome && strcmp(homedir, buf) == 0) {
afd501f9	453	debug3("secure_filename: terminating check at '%s'",
	454	buf);
	455	break;
	456	}
c8445989	457	/*
	458	* dirname should always complete with a "/" path,
	459	* but we can be paranoid and check for "." too
	460	*/
	461	if ((strcmp("/", buf) == 0) \|\| (strcmp(".", buf) == 0))
	462	break;
	463	}
	464	return 0;
	465	}
443fa1cd	466
	467	struct passwd *
	468	getpwnamallow(const char *user)
	469	{
1836f69f	470	#ifdef HAVE_LOGIN_CAP
	471	extern login_cap_t *lc;
	472	#ifdef BSD_AUTH
	473	auth_session_t *as;
	474	#endif
	475	#endif
443fa1cd	476	struct passwd *pw;
443fa1cd	477
d231781a	478	parse_server_match_config(&options, user,
	479	get_canonical_hostname(options.use_dns), get_remote_ipaddr());
	480
443fa1cd	481	pw = getpwnam(user);
c2802d92	482	if (pw == NULL) {
227a6a97	483	logit("Invalid user %.100s from %.100s",
c2802d92	484	user, get_remote_ipaddr());
73d9dad3	485	#ifdef CUSTOM_FAILED_LOGIN
575e336f	486	record_failed_login(user,
575e336f	487	get_canonical_hostname(options.use_dns), "ssh");
819d3f09	488	#endif
6039eeef	489	#ifdef SSH_AUDIT_EVENTS
	490	audit_event(SSH_INVALID_USER);
	491	#endif /* SSH_AUDIT_EVENTS */
c2802d92	492	return (NULL);
	493	}
	494	if (!allowed_user(pw))
1836f69f	495	return (NULL);
	496	#ifdef HAVE_LOGIN_CAP
	497	if ((lc = login_getclass(pw->pw_class)) == NULL) {
	498	debug("unable to get login class: %s", user);
	499	return (NULL);
	500	}
	501	#ifdef BSD_AUTH
	502	if ((as = auth_open()) == NULL \|\| auth_setpwd(as, pw) != 0 \|\|
65721f9c	503	auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
1836f69f	504	debug("Approval failure for %s", user);
443fa1cd	505	pw = NULL;
1836f69f	506	}
	507	if (as != NULL)
	508	auth_close(as);
	509	#endif
	510	#endif
06bea668	511	if (pw != NULL)
	512	return (pwcopy(pw));
	513	return (NULL);
443fa1cd	514	}
01dafcb5	515
	516	void
	517	auth_debug_add(const char *fmt,...)
	518	{
	519	char buf[1024];
	520	va_list args;
	521
	522	if (!auth_debug_init)
	523	return;
	524
	525	va_start(args, fmt);
	526	vsnprintf(buf, sizeof(buf), fmt, args);
	527	va_end(args);
	528	buffer_put_cstring(&auth_debug, buf);
	529	}
	530
	531	void
	532	auth_debug_send(void)
	533	{
	534	char *msg;
	535
	536	if (!auth_debug_init)
	537	return;
	538	while (buffer_len(&auth_debug)) {
	539	msg = buffer_get_string(&auth_debug, NULL);
	540	packet_send_debug("%s", msg);
	541	xfree(msg);
	542	}
	543	}
	544
	545	void
	546	auth_debug_reset(void)
	547	{
	548	if (auth_debug_init)
	549	buffer_clear(&auth_debug);
	550	else {
	551	buffer_init(&auth_debug);
	552	auth_debug_init = 1;
	553	}
	554	}
96d0bf74	555
	556	struct passwd *
	557	fakepw(void)
	558	{
	559	static struct passwd fake;
	560
	561	memset(&fake, 0, sizeof(fake));
	562	fake.pw_name = "NOUSER";
	563	fake.pw_passwd =
b6453d99	564	"$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
96d0bf74	565	fake.pw_gecos = "NOUSER";
f6be21a0	566	fake.pw_uid = (uid_t)-1;
f6be21a0	567	fake.pw_gid = (gid_t)-1;
96d0bf74	568	#ifdef HAVE_PW_CLASS_IN_PASSWD
	569	fake.pw_class = "";
	570	#endif
	571	fake.pw_dir = "/nonexist";
	572	fake.pw_shell = "/nonexist";
	573
	574	return (&fake);
	575	}