[gssapi-openssh.git] / openssh / 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 1.43 2002/05/17 14:27:55 millert 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
	if (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);
}

/*
 * 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 either 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;
	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) {
		snprintf(err, errlen, "realpath %s failed: %s", pw->pw_dir,
		    strerror(errno));
		return -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 (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 || !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
3c0ef626	1	/*
	2	* Copyright (c) 2000 Markus Friedl. All rights reserved.
	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.
	23	*/
	24
	25	#include "includes.h"
7435de97	26	RCSID("$OpenBSD: auth.c,v 1.43 2002/05/17 14:27:55 millert Exp $");
3c0ef626	27
	28	#ifdef HAVE_LOGIN_H
	29	#include <login.h>
	30	#endif
	31	#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW)
	32	#include <shadow.h>
	33	#endif /* defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) */
	34
	35	#ifdef HAVE_LIBGEN_H
	36	#include <libgen.h>
	37	#endif
	38
	39	#include "xmalloc.h"
	40	#include "match.h"
	41	#include "groupaccess.h"
	42	#include "log.h"
	43	#include "servconf.h"
	44	#include "auth.h"
	45	#include "auth-options.h"
	46	#include "canohost.h"
	47	#include "buffer.h"
	48	#include "bufaux.h"
	49	#include "uidswap.h"
	50	#include "tildexpand.h"
700318f3	51	#include "misc.h"
	52	#include "bufaux.h"
	53	#include "packet.h"
3c0ef626	54
	55	/* import */
	56	extern ServerOptions options;
	57
700318f3	58	/* Debugging messages */
	59	Buffer auth_debug;
	60	int auth_debug_init;
	61
3c0ef626	62	/*
	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.
	68	* If the user's shell is not executable, false will be returned.
	69	* Otherwise true is returned.
	70	*/
	71	int
	72	allowed_user(struct passwd * pw)
	73	{
	74	struct stat st;
	75	const char hostname = NULL, ipaddr = NULL;
	76	char *shell;
	77	int i;
	78	#ifdef WITH_AIXAUTHENTICATE
	79	char *loginmsg;
	80	#endif /* WITH_AIXAUTHENTICATE */
	81	#if !defined(USE_PAM) && defined(HAVE_SHADOW_H) && \
	82	!defined(DISABLE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
	83	struct spwd *spw;
	84
	85	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
	86	if (!pw \|\| !pw->pw_name)
	87	return 0;
	88
700318f3	89	#define DAY (24L * 60 * 60) /* 1 day in seconds */
3c0ef626	90	spw = getspnam(pw->pw_name);
3c0ef626	91	if (spw != NULL) {
700318f3	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);
	96
	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);
	103	return 0;
	104	}
3c0ef626	105
700318f3	106	if (spw->sp_lstchg == 0) {
	107	log("User %.100s password has expired (root forced)",
	108	pw->pw_name);
3c0ef626	109	return 0;
700318f3	110	}
3c0ef626	111
700318f3	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);
3c0ef626	116	return 0;
700318f3	117	}
3c0ef626	118	}
	119	#else
	120	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
	121	if (!pw \|\| !pw->pw_name)
	122	return 0;
	123	#endif
	124
	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 */
e9a17296	132	if (stat(shell, &st) != 0) {
	133	log("User %.100s not allowed because shell %.100s does not exist",
	134	pw->pw_name, shell);
3c0ef626	135	return 0;
e9a17296	136	}
700318f3	137	if (S_ISREG(st.st_mode) == 0 \|\|
700318f3	138	(st.st_mode & (S_IXOTH\|S_IXUSR\|S_IXGRP)) == 0) {
e9a17296	139	log("User %.100s not allowed because shell %.100s is not executable",
e9a17296	140	pw->pw_name, shell);
3c0ef626	141	return 0;
e9a17296	142	}
3c0ef626	143
3c0ef626	144	if (options.num_deny_users > 0 \|\| options.num_allow_users > 0) {
e9a17296	145	hostname = get_canonical_hostname(options.verify_reverse_mapping);
3c0ef626	146	ipaddr = get_remote_ipaddr();
	147	}
	148
	149	/* Return false if user is listed in DenyUsers */
	150	if (options.num_deny_users > 0) {
	151	for (i = 0; i < options.num_deny_users; i++)
700318f3	152	if (match_user(pw->pw_name, hostname, ipaddr,
e9a17296	153	options.deny_users[i])) {
700318f3	154	log("User %.100s not allowed because listed in DenyUsers",
700318f3	155	pw->pw_name);
3c0ef626	156	return 0;
e9a17296	157	}
3c0ef626	158	}
	159	/* Return false if AllowUsers isn't empty and user isn't listed there */
	160	if (options.num_allow_users > 0) {
	161	for (i = 0; i < options.num_allow_users; i++)
700318f3	162	if (match_user(pw->pw_name, hostname, ipaddr,
3c0ef626	163	options.allow_users[i]))
	164	break;
	165	/* i < options.num_allow_users iff we break for loop */
e9a17296	166	if (i >= options.num_allow_users) {
	167	log("User %.100s not allowed because not listed in AllowUsers",
	168	pw->pw_name);
3c0ef626	169	return 0;
e9a17296	170	}
3c0ef626	171	}
	172	if (options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
	173	/* Get the user's group access list (primary and supplementary) */
e9a17296	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);
3c0ef626	177	return 0;
e9a17296	178	}
3c0ef626	179
	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();
e9a17296	185	log("User %.100s not allowed because a group is listed in DenyGroups",
e9a17296	186	pw->pw_name);
3c0ef626	187	return 0;
	188	}
	189	/*
	190	* Return false if AllowGroups isn't empty and one of user's groups
	191	* isn't listed there
	192	*/
	193	if (options.num_allow_groups > 0)
	194	if (!ga_match(options.allow_groups,
	195	options.num_allow_groups)) {
	196	ga_free();
e9a17296	197	log("User %.100s not allowed because none of user's groups are listed in AllowGroups",
e9a17296	198	pw->pw_name);
3c0ef626	199	return 0;
	200	}
	201	ga_free();
	202	}
	203
	204	#ifdef WITH_AIXAUTHENTICATE
	205	if (loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &loginmsg) != 0) {
	206	if (loginmsg && *loginmsg) {
	207	/* Remove embedded newlines (if any) */
	208	char *p;
	209	for (p = loginmsg; *p; p++) {
	210	if (*p == '\n')
	211	*p = ' ';
	212	}
	213	/* Remove trailing newline */
	214	*--p = '\0';
	215	log("Login restricted for %s: %.100s", pw->pw_name, loginmsg);
	216	}
	217	return 0;
	218	}
	219	#endif /* WITH_AIXAUTHENTICATE */
	220
	221	/* We found no reason not to let this user try to log on... */
	222	return 1;
	223	}
	224
	225	Authctxt *
	226	authctxt_new(void)
	227	{
	228	Authctxt authctxt = xmalloc(sizeof(authctxt));
	229	memset(authctxt, 0, sizeof(*authctxt));
	230	return authctxt;
	231	}
	232
	233	void
	234	auth_log(Authctxt authctxt, int authenticated, char method, char *info)
	235	{
	236	void (authlog) (const char fmt,...) = verbose;
	237	char *authmsg;
	238
	239	/* Raise logging level */
	240	if (authenticated == 1 \|\|
	241	!authctxt->valid \|\|
	242	authctxt->failures >= AUTH_FAIL_LOG \|\|
	243	strcmp(method, "password") == 0)
	244	authlog = log;
	245
	246	if (authctxt->postponed)
	247	authmsg = "Postponed";
	248	else
	249	authmsg = authenticated ? "Accepted" : "Failed";
	250
	251	authlog("%s %s for %s%.100s from %.200s port %d%s",
	252	authmsg,
	253	method,
	254	authctxt->valid ? "" : "illegal user ",
	255	authctxt->user,
	256	get_remote_ipaddr(),
	257	get_remote_port(),
	258	info);
	259	}
	260
	261	/*
	262	* Check whether root logins are disallowed.
263	*/
264	int
265	auth_root_allowed(char *method)
266	{
267	switch (options.permit_root_login) {
268	case PERMIT_YES:
269	return 1;
270	break;
271	case PERMIT_NO_PASSWD:
272	if (strcmp(method, "password") != 0)
273	return 1;
274	break;
275	case PERMIT_FORCED_ONLY:
276	if (forced_command) {
277	log("Root login accepted for forced command.");
278	return 1;
279	}
280	break;
281	}
282	log("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
283	return 0;
284	}
285
286
287	/*
288	* Given a template and a passwd structure, build a filename
289	* by substituting % tokenised options. Currently, %% becomes '%',
290	* %h becomes the home directory and %u the username.
291	*
292	* This returns a buffer allocated by xmalloc.
293	*/
294	char *
295	expand_filename(const char filename, struct passwd pw)
296	{
297	Buffer buffer;
298	char *file;
299	const char *cp;
300
301	/*
302	* Build the filename string in the buffer by making the appropriate
303	* substitutions to the given file name.
304	*/
305	buffer_init(&buffer);
306	for (cp = filename; *cp; cp++) {
307	if (cp[0] == '%' && cp[1] == '%') {
308	buffer_append(&buffer, "%", 1);
309	cp++;
310	continue;
311	}
312	if (cp[0] == '%' && cp[1] == 'h') {
313	buffer_append(&buffer, pw->pw_dir, strlen(pw->pw_dir));
314	cp++;
315	continue;
316	}
317	if (cp[0] == '%' && cp[1] == 'u') {
318	buffer_append(&buffer, pw->pw_name,
e9a17296	319	strlen(pw->pw_name));
3c0ef626	320	cp++;
	321	continue;
	322	}
	323	buffer_append(&buffer, cp, 1);
	324	}
	325	buffer_append(&buffer, "\0", 1);
	326
	327	/*
	328	* Ensure that filename starts anchored. If not, be backward
	329	* compatible and prepend the '%h/'
	330	*/
	331	file = xmalloc(MAXPATHLEN);
	332	cp = buffer_ptr(&buffer);
	333	if (*cp != '/')
	334	snprintf(file, MAXPATHLEN, "%s/%s", pw->pw_dir, cp);
	335	else
	336	strlcpy(file, cp, MAXPATHLEN);
	337
	338	buffer_free(&buffer);
	339	return file;
	340	}
	341
	342	char *
	343	authorized_keys_file(struct passwd *pw)
	344	{
	345	return expand_filename(options.authorized_keys_file, pw);
	346	}
	347
	348	char *
	349	authorized_keys_file2(struct passwd *pw)
	350	{
	351	return expand_filename(options.authorized_keys_file2, pw);
	352	}
	353
	354	/* return ok if key exists in sysfile or userfile */
	355	HostStatus
	356	check_key_in_hostfiles(struct passwd pw, Key key, const char *host,
	357	const char sysfile, const char userfile)
	358	{
	359	Key *found;
	360	char *user_hostfile;
	361	struct stat st;
e9a17296	362	HostStatus host_status;
3c0ef626	363
	364	/* Check if we know the host and its host key. */
	365	found = key_new(key->type);
	366	host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
	367
	368	if (host_status != HOST_OK && userfile != NULL) {
	369	user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
	370	if (options.strict_modes &&
	371	(stat(user_hostfile, &st) == 0) &&
	372	((st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
e9a17296	373	(st.st_mode & 022) != 0)) {
3c0ef626	374	log("Authentication refused for %.100s: "
	375	"bad owner or modes for %.200s",
	376	pw->pw_name, user_hostfile);
	377	} else {
	378	temporarily_use_uid(pw);
	379	host_status = check_host_in_hostfile(user_hostfile,
	380	host, key, found, NULL);
	381	restore_uid();
	382	}
	383	xfree(user_hostfile);
	384	}
	385	key_free(found);
	386
	387	debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
	388	"ok" : "not found", host);
	389	return host_status;
	390	}
	391
	392
	393	/*
	394	* Check a given file for security. This is defined as all components
	395	* of the path to the file must either be owned by either the owner of
	396	* of the file or root and no directories must be group or world writable.
	397	*
	398	* XXX Should any specific check be done for sym links ?
	399	*
	400	* Takes an open file descriptor, the file name, a uid and and
	401	* error buffer plus max size as arguments.
	402	*
	403	* Returns 0 on success and -1 on failure
	404	*/
	405	int
	406	secure_filename(FILE f, const char file, struct passwd *pw,
	407	char *err, size_t errlen)
	408	{
	409	uid_t uid = pw->pw_uid;
	410	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
	411	char *cp;
	412	struct stat st;
	413
	414	if (realpath(file, buf) == NULL) {
	415	snprintf(err, errlen, "realpath %s failed: %s", file,
	416	strerror(errno));
	417	return -1;
	418	}
	419	if (realpath(pw->pw_dir, homedir) == NULL) {
	420	snprintf(err, errlen, "realpath %s failed: %s", pw->pw_dir,
	421	strerror(errno));
	422	return -1;
	423	}
	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) {
e9a17296	446	snprintf(err, errlen,
3c0ef626	447	"bad ownership or modes for directory %s", buf);
	448	return -1;
	449	}
	450
	451	/* If are passed the homedir then we can stop */
	452	if (strcmp(homedir, buf) == 0) {
	453	debug3("secure_filename: terminating check at '%s'",
	454	buf);
	455	break;
	456	}
	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	}
700318f3	466
	467	struct passwd *
	468	getpwnamallow(const char *user)
	469	{
	470	#ifdef HAVE_LOGIN_CAP
	471	extern login_cap_t *lc;
	472	#ifdef BSD_AUTH
	473	auth_session_t *as;
	474	#endif
	475	#endif
	476	struct passwd *pw;
	477
	478	pw = getpwnam(user);
	479	if (pw == NULL \|\| !allowed_user(pw))
	480	return (NULL);
	481	#ifdef HAVE_LOGIN_CAP
	482	if ((lc = login_getclass(pw->pw_class)) == NULL) {
	483	debug("unable to get login class: %s", user);
	484	return (NULL);
	485	}
	486	#ifdef BSD_AUTH
	487	if ((as = auth_open()) == NULL \|\| auth_setpwd(as, pw) != 0 \|\|
7435de97	488	auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
700318f3	489	debug("Approval failure for %s", user);
	490	pw = NULL;
	491	}
	492	if (as != NULL)
	493	auth_close(as);
	494	#endif
	495	#endif
	496	if (pw != NULL)
	497	return (pwcopy(pw));
	498	return (NULL);
	499	}
	500
	501	void
	502	auth_debug_add(const char *fmt,...)
	503	{
	504	char buf[1024];
	505	va_list args;
	506
	507	if (!auth_debug_init)
	508	return;
	509
	510	va_start(args, fmt);
	511	vsnprintf(buf, sizeof(buf), fmt, args);
	512	va_end(args);
	513	buffer_put_cstring(&auth_debug, buf);
	514	}
	515
	516	void
	517	auth_debug_send(void)
	518	{
	519	char *msg;
	520
	521	if (!auth_debug_init)
	522	return;
	523	while (buffer_len(&auth_debug)) {
	524	msg = buffer_get_string(&auth_debug, NULL);
	525	packet_send_debug("%s", msg);
	526	xfree(msg);
	527	}
	528	}
	529
	530	void
	531	auth_debug_reset(void)
	532	{
	533	if (auth_debug_init)
	534	buffer_clear(&auth_debug);
	535	else {
	536	buffer_init(&auth_debug);
	537	auth_debug_init = 1;
	538	}
	539	}