[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 1.46 2002/11/04 10:07:53 markus Exp $");

#ifdef HAVE_LOGIN_H
#include <login.h>
#endif
#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
#include <shadow.h>
#endif /* defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) */

#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 "tildexpand.h"
#include "misc.h"
#include "bufaux.h"
#include "packet.h"

/* import */
extern ServerOptions options;

/* 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;
	char *shell;
	int i;
#ifdef WITH_AIXAUTHENTICATE
	char *loginmsg;
#endif /* WITH_AIXAUTHENTICATE */
#if !defined(USE_PAM) && defined(HAVE_SHADOW_H) && \
	!defined(DISABLE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
	struct spwd *spw;

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

#define	DAY		(24L * 60 * 60) /* 1 day in seconds */
	spw = getspnam(pw->pw_name);
	if (spw != NULL) {
		time_t today = time(NULL) / DAY;
		debug3("allowed_user: today %d sp_expire %d sp_lstchg %d"
		    " sp_max %d", (int)today, (int)spw->sp_expire,
		    (int)spw->sp_lstchg, (int)spw->sp_max);

		/*
		 * We assume account and password expiration occurs the
		 * day after the day specified.
		 */
		if (spw->sp_expire != -1 && today > spw->sp_expire) {
			log("Account %.100s has expired", pw->pw_name);
			return 0;
		}

		if (spw->sp_lstchg == 0) {
			log("User %.100s password has expired (root forced)",
			    pw->pw_name);
			return 0;
		}

		if (spw->sp_max != -1 &&
		    today > spw->sp_lstchg + spw->sp_max) {
			log("User %.100s password has expired (password aged)",
			    pw->pw_name);
			return 0;
		}
	}
#else
	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
	if (!pw || !pw->pw_name)
		return 0;
#endif

	/*
	 * 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) {
		log("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) {
		log("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) {
		hostname = get_canonical_hostname(options.verify_reverse_mapping);
		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])) {
				log("User %.100s not allowed because listed in DenyUsers",
				    pw->pw_name);
				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) {
			log("User %.100s not allowed because not listed in AllowUsers",
			    pw->pw_name);
			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) {
			log("User %.100s not allowed because not in any group",
			    pw->pw_name);
			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();
				log("User %.100s not allowed because a group is listed in DenyGroups",
				    pw->pw_name);
				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();
				log("User %.100s not allowed because none of user's groups are listed in AllowGroups",
				    pw->pw_name);
				return 0;
			}
		ga_free();
	}

#ifdef WITH_AIXAUTHENTICATE
	/*
	 * Don't check loginrestrictions() for root account (use
	 * PermitRootLogin to control logins via ssh), or if running as
	 * non-root user (since loginrestrictions will always fail).
	 */
	if ( (pw->pw_uid != 0) && (geteuid() == 0) &&
	    loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &loginmsg) != 0) {
		if (loginmsg && *loginmsg) {
			/* Remove embedded newlines (if any) */
			char *p;
			for (p = loginmsg; *p; p++) {
				if (*p == '\n')
					*p = ' ';
			}
			/* Remove trailing newline */
			*--p = '\0';
			log("Login restricted for %s: %.100s", pw->pw_name, loginmsg);
		}
		return 0;
	}
#endif /* WITH_AIXAUTHENTICATE */

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

Authctxt *
authctxt_new(void)
{
	Authctxt *authctxt = xmalloc(sizeof(*authctxt));
	memset(authctxt, 0, sizeof(*authctxt));
	return authctxt;
}

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 >= AUTH_FAIL_LOG ||
	    strcmp(method, "password") == 0)
		authlog = log;

	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 ? "" : "illegal user ",
	    authctxt->user,
	    get_remote_ipaddr(),
	    get_remote_port(),
	    info);

#ifdef WITH_AIXAUTHENTICATE
	if (authenticated == 0 && strcmp(method, "password") == 0)
	    loginfailed(authctxt->user,
		get_canonical_hostname(options.verify_reverse_mapping),
		"ssh");
#endif /* WITH_AIXAUTHENTICATE */

}

/*
 * 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) {
			log("Root login accepted for forced command.");
			return 1;
		}
		break;
	}
	log("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.
 */
char *
expand_filename(const char *filename, struct passwd *pw)
{
	Buffer buffer;
	char *file;
	const char *cp;

	/*
	 * Build the filename string in the buffer by making the appropriate
	 * substitutions to the given file name.
	 */
	buffer_init(&buffer);
	for (cp = filename; *cp; cp++) {
		if (cp[0] == '%' && cp[1] == '%') {
			buffer_append(&buffer, "%", 1);
			cp++;
			continue;
		}
		if (cp[0] == '%' && cp[1] == 'h') {
			buffer_append(&buffer, pw->pw_dir, strlen(pw->pw_dir));
			cp++;
			continue;
		}
		if (cp[0] == '%' && cp[1] == 'u') {
			buffer_append(&buffer, pw->pw_name,
			    strlen(pw->pw_name));
			cp++;
			continue;
		}
		buffer_append(&buffer, cp, 1);
	}
	buffer_append(&buffer, "\0", 1);

	/*
	 * Ensure that filename starts anchored. If not, be backward
	 * compatible and prepend the '%h/'
	 */
	file = xmalloc(MAXPATHLEN);
	cp = buffer_ptr(&buffer);
	if (*cp != '/')
		snprintf(file, MAXPATHLEN, "%s/%s", pw->pw_dir, cp);
	else
		strlcpy(file, cp, MAXPATHLEN);

	buffer_free(&buffer);
	return file;
}

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

char *
authorized_keys_file2(struct passwd *pw)
{
	return expand_filename(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)) {
			log("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) {
		log("Illegal user %.100s from %.100s",
		    user, get_remote_ipaddr());
		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;
	}
}
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"
f6f02456	26	RCSID("$OpenBSD: auth.c,v 1.46 2002/11/04 10:07:53 markus Exp $");
7368a6c8	27
c1ef8333	28	#ifdef HAVE_LOGIN_H
	29	#include <login.h>
	30	#endif
4cb5ffa0	31	#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
	32	#include <shadow.h>
	33	#endif /* defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) */
7368a6c8	34
b4d02860	35	#ifdef HAVE_LIBGEN_H
c8445989	36	#include <libgen.h>
b4d02860	37	#endif
c8445989	38
42f11eb2	39	#include "xmalloc.h"
	40	#include "match.h"
	41	#include "groupaccess.h"
	42	#include "log.h"
	43	#include "servconf.h"
e78a59f5	44	#include "auth.h"
59c97189	45	#include "auth-options.h"
42f11eb2	46	#include "canohost.h"
c8445989	47	#include "buffer.h"
c8445989	48	#include "bufaux.h"
d0c8ca5c	49	#include "uidswap.h"
d0c8ca5c	50	#include "tildexpand.h"
5f1f36b5	51	#include "misc.h"
01dafcb5	52	#include "bufaux.h"
01dafcb5	53	#include "packet.h"
e78a59f5	54
7368a6c8	55	/* import */
7368a6c8	56	extern ServerOptions options;
7368a6c8	57
01dafcb5	58	/* Debugging messages */
	59	Buffer auth_debug;
	60	int auth_debug_init;
	61
7368a6c8	62	/*
c6a69271	63	* Check if the user is allowed to log in via ssh. If user is listed
	64	* in DenyUsers or one of user's groups is listed in DenyGroups, false
	65	* will be returned. If AllowUsers isn't empty and user isn't listed
	66	* there, or if AllowGroups isn't empty and one of user's groups isn't
	67	* listed there, false will be returned.
7368a6c8	68	* If the user's shell is not executable, false will be returned.
6ae2364d	69	* Otherwise true is returned.
7368a6c8	70	*/
a306f2dd	71	int
7368a6c8	72	allowed_user(struct passwd * pw)
	73	{
	74	struct stat st;
6805fc56	75	const char hostname = NULL, ipaddr = NULL;
614dee3a	76	char *shell;
7368a6c8	77	int i;
	78	#ifdef WITH_AIXAUTHENTICATE
	79	char *loginmsg;
	80	#endif /* WITH_AIXAUTHENTICATE */
75b90ced	81	#if !defined(USE_PAM) && defined(HAVE_SHADOW_H) && \
37c1c46d	82	!defined(DISABLE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
c6a69271	83	struct spwd *spw;
7368a6c8	84
7368a6c8	85	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
c6a69271	86	if (!pw \|\| !pw->pw_name)
7368a6c8	87	return 0;
7368a6c8	88
5b29f152	89	#define DAY (24L * 60 * 60) /* 1 day in seconds */
4cb5ffa0	90	spw = getspnam(pw->pw_name);
27494968	91	if (spw != NULL) {
5b29f152	92	time_t today = time(NULL) / DAY;
	93	debug3("allowed_user: today %d sp_expire %d sp_lstchg %d"
	94	" sp_max %d", (int)today, (int)spw->sp_expire,
	95	(int)spw->sp_lstchg, (int)spw->sp_max);
4cb5ffa0	96
5b29f152	97	/*
	98	* We assume account and password expiration occurs the
	99	* day after the day specified.
	100	*/
	101	if (spw->sp_expire != -1 && today > spw->sp_expire) {
	102	log("Account %.100s has expired", pw->pw_name);
27494968	103	return 0;
5b29f152	104	}
27494968	105
5b29f152	106	if (spw->sp_lstchg == 0) {
	107	log("User %.100s password has expired (root forced)",
	108	pw->pw_name);
27494968	109	return 0;
5b29f152	110	}
	111
	112	if (spw->sp_max != -1 &&
	113	today > spw->sp_lstchg + spw->sp_max) {
	114	log("User %.100s password has expired (password aged)",
	115	pw->pw_name);
	116	return 0;
	117	}
27494968	118	}
4cb5ffa0	119	#else
4cb5ffa0	120	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
c6a69271	121	if (!pw \|\| !pw->pw_name)
4cb5ffa0	122	return 0;
	123	#endif
	124
301e9b01	125	/*
	126	* Get the shell from the password data. An empty shell field is
	127	* legal, and means /bin/sh.
	128	*/
	129	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
	130
	131	/* deny if shell does not exists or is not executable */
b334badd	132	if (stat(shell, &st) != 0) {
	133	log("User %.100s not allowed because shell %.100s does not exist",
	134	pw->pw_name, shell);
7368a6c8	135	return 0;
b334badd	136	}
c390a3c8	137	if (S_ISREG(st.st_mode) == 0 \|\|
c390a3c8	138	(st.st_mode & (S_IXOTH\|S_IXUSR\|S_IXGRP)) == 0) {
b334badd	139	log("User %.100s not allowed because shell %.100s is not executable",
b334badd	140	pw->pw_name, shell);
7368a6c8	141	return 0;
b334badd	142	}
7368a6c8	143
6805fc56	144	if (options.num_deny_users > 0 \|\| options.num_allow_users > 0) {
	145	hostname = get_canonical_hostname(options.verify_reverse_mapping);
	146	ipaddr = get_remote_ipaddr();
	147	}
	148
7368a6c8	149	/* Return false if user is listed in DenyUsers */
7368a6c8	150	if (options.num_deny_users > 0) {
7368a6c8	151	for (i = 0; i < options.num_deny_users; i++)
762715ce	152	if (match_user(pw->pw_name, hostname, ipaddr,
b334badd	153	options.deny_users[i])) {
762715ce	154	log("User %.100s not allowed because listed in DenyUsers",
762715ce	155	pw->pw_name);
7368a6c8	156	return 0;
b334badd	157	}
7368a6c8	158	}
	159	/* Return false if AllowUsers isn't empty and user isn't listed there */
	160	if (options.num_allow_users > 0) {
7368a6c8	161	for (i = 0; i < options.num_allow_users; i++)
762715ce	162	if (match_user(pw->pw_name, hostname, ipaddr,
80f8f24f	163	options.allow_users[i]))
7368a6c8	164	break;
7368a6c8	165	/* i < options.num_allow_users iff we break for loop */
b334badd	166	if (i >= options.num_allow_users) {
	167	log("User %.100s not allowed because not listed in AllowUsers",
	168	pw->pw_name);
7368a6c8	169	return 0;
b334badd	170	}
7368a6c8	171	}
7368a6c8	172	if (options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
c6a69271	173	/* Get the user's group access list (primary and supplementary) */
b334badd	174	if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
	175	log("User %.100s not allowed because not in any group",
	176	pw->pw_name);
7368a6c8	177	return 0;
b334badd	178	}
7368a6c8	179
c6a69271	180	/* Return false if one of user's groups is listed in DenyGroups */
	181	if (options.num_deny_groups > 0)
	182	if (ga_match(options.deny_groups,
	183	options.num_deny_groups)) {
	184	ga_free();
b334badd	185	log("User %.100s not allowed because a group is listed in DenyGroups",
b334badd	186	pw->pw_name);
7368a6c8	187	return 0;
c6a69271	188	}
7368a6c8	189	/*
c6a69271	190	* Return false if AllowGroups isn't empty and one of user's groups
7368a6c8	191	* isn't listed there
7368a6c8	192	*/
c6a69271	193	if (options.num_allow_groups > 0)
	194	if (!ga_match(options.allow_groups,
	195	options.num_allow_groups)) {
	196	ga_free();
b334badd	197	log("User %.100s not allowed because none of user's groups are listed in AllowGroups",
b334badd	198	pw->pw_name);
7368a6c8	199	return 0;
c6a69271	200	}
c6a69271	201	ga_free();
7368a6c8	202	}
	203
	204	#ifdef WITH_AIXAUTHENTICATE
f3e87063	205	/*
	206	* Don't check loginrestrictions() for root account (use
	207	* PermitRootLogin to control logins via ssh), or if running as
	208	* non-root user (since loginrestrictions will always fail).
	209	*/
	210	if ( (pw->pw_uid != 0) && (geteuid() == 0) &&
	211	loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &loginmsg) != 0) {
c1ef8333	212	if (loginmsg && *loginmsg) {
	213	/* Remove embedded newlines (if any) */
	214	char *p;
5daf7064	215	for (p = loginmsg; *p; p++) {
c1ef8333	216	if (*p == '\n')
c1ef8333	217	*p = ' ';
5daf7064	218	}
c1ef8333	219	/* Remove trailing newline */
c1ef8333	220	*--p = '\0';
5daf7064	221	log("Login restricted for %s: %.100s", pw->pw_name, loginmsg);
c1ef8333	222	}
7368a6c8	223	return 0;
c1ef8333	224	}
7368a6c8	225	#endif /* WITH_AIXAUTHENTICATE */
	226
	227	/* We found no reason not to let this user try to log on... */
	228	return 1;
	229	}
59c97189	230
	231	Authctxt *
	232	authctxt_new(void)
	233	{
2b87da3b	234	Authctxt authctxt = xmalloc(sizeof(authctxt));
	235	memset(authctxt, 0, sizeof(*authctxt));
	236	return authctxt;
59c97189	237	}
59c97189	238
59c97189	239	void
	240	auth_log(Authctxt authctxt, int authenticated, char method, char *info)
	241	{
	242	void (authlog) (const char fmt,...) = verbose;
	243	char *authmsg;
	244
	245	/* Raise logging level */
	246	if (authenticated == 1 \|\|
	247	!authctxt->valid \|\|
	248	authctxt->failures >= AUTH_FAIL_LOG \|\|
	249	strcmp(method, "password") == 0)
	250	authlog = log;
	251
	252	if (authctxt->postponed)
	253	authmsg = "Postponed";
	254	else
	255	authmsg = authenticated ? "Accepted" : "Failed";
	256
	257	authlog("%s %s for %s%.100s from %.200s port %d%s",
	258	authmsg,
	259	method,
	260	authctxt->valid ? "" : "illegal user ",
fad3754c	261	authctxt->user,
59c97189	262	get_remote_ipaddr(),
	263	get_remote_port(),
	264	info);
56fd97d7	265
	266	#ifdef WITH_AIXAUTHENTICATE
	267	if (authenticated == 0 && strcmp(method, "password") == 0)
	268	loginfailed(authctxt->user,
	269	get_canonical_hostname(options.verify_reverse_mapping),
	270	"ssh");
	271	#endif /* WITH_AIXAUTHENTICATE */
	272
59c97189	273	}
	274
	275	/*
15853e93	276	* Check whether root logins are disallowed.
59c97189	277	*/
59c97189	278	int
15853e93	279	auth_root_allowed(char *method)
59c97189	280	{
15853e93	281	switch (options.permit_root_login) {
15853e93	282	case PERMIT_YES:
59c97189	283	return 1;
15853e93	284	break;
	285	case PERMIT_NO_PASSWD:
	286	if (strcmp(method, "password") != 0)
	287	return 1;
	288	break;
	289	case PERMIT_FORCED_ONLY:
	290	if (forced_command) {
	291	log("Root login accepted for forced command.");
	292	return 1;
	293	}
	294	break;
59c97189	295	}
15853e93	296	log("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
15853e93	297	return 0;
59c97189	298	}
c8445989	299
	300
	301	/*
	302	* Given a template and a passwd structure, build a filename
	303	* by substituting % tokenised options. Currently, %% becomes '%',
	304	* %h becomes the home directory and %u the username.
	305	*
	306	* This returns a buffer allocated by xmalloc.
	307	*/
	308	char *
	309	expand_filename(const char filename, struct passwd pw)
	310	{
	311	Buffer buffer;
	312	char *file;
	313	const char *cp;
	314
	315	/*
	316	* Build the filename string in the buffer by making the appropriate
	317	* substitutions to the given file name.
	318	*/
	319	buffer_init(&buffer);
	320	for (cp = filename; *cp; cp++) {
	321	if (cp[0] == '%' && cp[1] == '%') {
	322	buffer_append(&buffer, "%", 1);
	323	cp++;
	324	continue;
	325	}
	326	if (cp[0] == '%' && cp[1] == 'h') {
	327	buffer_append(&buffer, pw->pw_dir, strlen(pw->pw_dir));
	328	cp++;
	329	continue;
	330	}
	331	if (cp[0] == '%' && cp[1] == 'u') {
	332	buffer_append(&buffer, pw->pw_name,
184eed6a	333	strlen(pw->pw_name));
c8445989	334	cp++;
	335	continue;
	336	}
	337	buffer_append(&buffer, cp, 1);
	338	}
	339	buffer_append(&buffer, "\0", 1);
	340
	341	/*
	342	* Ensure that filename starts anchored. If not, be backward
	343	* compatible and prepend the '%h/'
	344	*/
	345	file = xmalloc(MAXPATHLEN);
	346	cp = buffer_ptr(&buffer);
	347	if (*cp != '/')
	348	snprintf(file, MAXPATHLEN, "%s/%s", pw->pw_dir, cp);
	349	else
	350	strlcpy(file, cp, MAXPATHLEN);
	351
	352	buffer_free(&buffer);
	353	return file;
	354	}
	355
	356	char *
	357	authorized_keys_file(struct passwd *pw)
	358	{
	359	return expand_filename(options.authorized_keys_file, pw);
	360	}
	361
	362	char *
	363	authorized_keys_file2(struct passwd *pw)
	364	{
	365	return expand_filename(options.authorized_keys_file2, pw);
	366	}
	367
d0c8ca5c	368	/* return ok if key exists in sysfile or userfile */
	369	HostStatus
	370	check_key_in_hostfiles(struct passwd pw, Key key, const char *host,
	371	const char sysfile, const char userfile)
	372	{
	373	Key *found;
	374	char *user_hostfile;
	375	struct stat st;
17a3011c	376	HostStatus host_status;
d0c8ca5c	377
	378	/* Check if we know the host and its host key. */
	379	found = key_new(key->type);
	380	host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
	381
	382	if (host_status != HOST_OK && userfile != NULL) {
	383	user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
	384	if (options.strict_modes &&
	385	(stat(user_hostfile, &st) == 0) &&
	386	((st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
184eed6a	387	(st.st_mode & 022) != 0)) {
d0c8ca5c	388	log("Authentication refused for %.100s: "
	389	"bad owner or modes for %.200s",
	390	pw->pw_name, user_hostfile);
	391	} else {
	392	temporarily_use_uid(pw);
	393	host_status = check_host_in_hostfile(user_hostfile,
	394	host, key, found, NULL);
	395	restore_uid();
	396	}
	397	xfree(user_hostfile);
	398	}
	399	key_free(found);
	400
	401	debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
	402	"ok" : "not found", host);
	403	return host_status;
	404	}
	405
	406
c8445989	407	/*
c8445989	408	* Check a given file for security. This is defined as all components
d6097023	409	* of the path to the file must be owned by either the owner of
1ddf764b	410	* of the file or root and no directories must be group or world writable.
c8445989	411	*
	412	* XXX Should any specific check be done for sym links ?
	413	*
	414	* Takes an open file descriptor, the file name, a uid and and
	415	* error buffer plus max size as arguments.
	416	*
	417	* Returns 0 on success and -1 on failure
	418	*/
	419	int
6978866a	420	secure_filename(FILE f, const char file, struct passwd *pw,
6978866a	421	char *err, size_t errlen)
c8445989	422	{
6978866a	423	uid_t uid = pw->pw_uid;
76fbdd47	424	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
c8445989	425	char *cp;
f6f02456	426	int comparehome = 0;
c8445989	427	struct stat st;
	428
	429	if (realpath(file, buf) == NULL) {
	430	snprintf(err, errlen, "realpath %s failed: %s", file,
	431	strerror(errno));
	432	return -1;
	433	}
f6f02456	434	if (realpath(pw->pw_dir, homedir) != NULL)
f6f02456	435	comparehome = 1;
c8445989	436
	437	/* check the open file to avoid races */
	438	if (fstat(fileno(f), &st) < 0 \|\|
	439	(st.st_uid != 0 && st.st_uid != uid) \|\|
	440	(st.st_mode & 022) != 0) {
	441	snprintf(err, errlen, "bad ownership or modes for file %s",
	442	buf);
	443	return -1;
	444	}
	445
	446	/* for each component of the canonical path, walking upwards */
	447	for (;;) {
	448	if ((cp = dirname(buf)) == NULL) {
	449	snprintf(err, errlen, "dirname() failed");
	450	return -1;
	451	}
	452	strlcpy(buf, cp, sizeof(buf));
	453
	454	debug3("secure_filename: checking '%s'", buf);
	455	if (stat(buf, &st) < 0 \|\|
	456	(st.st_uid != 0 && st.st_uid != uid) \|\|
	457	(st.st_mode & 022) != 0) {
184eed6a	458	snprintf(err, errlen,
c8445989	459	"bad ownership or modes for directory %s", buf);
	460	return -1;
	461	}
	462
afd501f9	463	/* If are passed the homedir then we can stop */
f6f02456	464	if (comparehome && strcmp(homedir, buf) == 0) {
afd501f9	465	debug3("secure_filename: terminating check at '%s'",
	466	buf);
	467	break;
	468	}
c8445989	469	/*
	470	* dirname should always complete with a "/" path,
	471	* but we can be paranoid and check for "." too
	472	*/
	473	if ((strcmp("/", buf) == 0) \|\| (strcmp(".", buf) == 0))
	474	break;
	475	}
	476	return 0;
	477	}
443fa1cd	478
	479	struct passwd *
	480	getpwnamallow(const char *user)
	481	{
1836f69f	482	#ifdef HAVE_LOGIN_CAP
	483	extern login_cap_t *lc;
	484	#ifdef BSD_AUTH
	485	auth_session_t *as;
	486	#endif
	487	#endif
443fa1cd	488	struct passwd *pw;
	489
	490	pw = getpwnam(user);
c2802d92	491	if (pw == NULL) {
	492	log("Illegal user %.100s from %.100s",
	493	user, get_remote_ipaddr());
	494	return (NULL);
	495	}
	496	if (!allowed_user(pw))
1836f69f	497	return (NULL);
	498	#ifdef HAVE_LOGIN_CAP
	499	if ((lc = login_getclass(pw->pw_class)) == NULL) {
	500	debug("unable to get login class: %s", user);
	501	return (NULL);
	502	}
	503	#ifdef BSD_AUTH
	504	if ((as = auth_open()) == NULL \|\| auth_setpwd(as, pw) != 0 \|\|
65721f9c	505	auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
1836f69f	506	debug("Approval failure for %s", user);
443fa1cd	507	pw = NULL;
1836f69f	508	}
	509	if (as != NULL)
	510	auth_close(as);
	511	#endif
	512	#endif
06bea668	513	if (pw != NULL)
	514	return (pwcopy(pw));
	515	return (NULL);
443fa1cd	516	}
01dafcb5	517
	518	void
	519	auth_debug_add(const char *fmt,...)
	520	{
	521	char buf[1024];
	522	va_list args;
	523
	524	if (!auth_debug_init)
	525	return;
	526
	527	va_start(args, fmt);
	528	vsnprintf(buf, sizeof(buf), fmt, args);
	529	va_end(args);
	530	buffer_put_cstring(&auth_debug, buf);
	531	}
	532
	533	void
	534	auth_debug_send(void)
	535	{
	536	char *msg;
	537
	538	if (!auth_debug_init)
	539	return;
	540	while (buffer_len(&auth_debug)) {
	541	msg = buffer_get_string(&auth_debug, NULL);
	542	packet_send_debug("%s", msg);
	543	xfree(msg);
	544	}
	545	}
	546
	547	void
	548	auth_debug_reset(void)
	549	{
	550	if (auth_debug_init)
	551	buffer_clear(&auth_debug);
	552	else {
	553	buffer_init(&auth_debug);
	554	auth_debug_init = 1;
	555	}
	556	}