[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 1.41 2002/03/19 15:31:47 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"

/* import */
extern ServerOptions options;

/*
 * 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;

	spw = getspnam(pw->pw_name);
	if (spw != NULL) {
		int days = time(NULL) / 86400;

		/* Check account expiry */
		if ((spw->sp_expire >= 0) && (days > spw->sp_expire))
			return 0;

		/* Check password expiry */
		if ((spw->sp_lstchg >= 0) && (spw->sp_max >= 0) &&
		    (days > (spw->sp_lstchg + spw->sp_max)))
			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(NULL, 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);
}
Commit	Line	Data
7368a6c8	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"
06bea668	26	RCSID("$OpenBSD: auth.c,v 1.41 2002/03/19 15:31:47 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"
e78a59f5	52
7368a6c8	53	/* import */
7368a6c8	54	extern ServerOptions options;
7368a6c8	55
7368a6c8	56	/*
c6a69271	57	* Check if the user is allowed to log in via ssh. If user is listed
	58	* in DenyUsers or one of user's groups is listed in DenyGroups, false
	59	* will be returned. If AllowUsers isn't empty and user isn't listed
	60	* there, or if AllowGroups isn't empty and one of user's groups isn't
	61	* listed there, false will be returned.
7368a6c8	62	* If the user's shell is not executable, false will be returned.
6ae2364d	63	* Otherwise true is returned.
7368a6c8	64	*/
a306f2dd	65	int
7368a6c8	66	allowed_user(struct passwd * pw)
	67	{
	68	struct stat st;
6805fc56	69	const char hostname = NULL, ipaddr = NULL;
614dee3a	70	char *shell;
7368a6c8	71	int i;
	72	#ifdef WITH_AIXAUTHENTICATE
	73	char *loginmsg;
	74	#endif /* WITH_AIXAUTHENTICATE */
75b90ced	75	#if !defined(USE_PAM) && defined(HAVE_SHADOW_H) && \
37c1c46d	76	!defined(DISABLE_SHADOW) && defined(HAS_SHADOW_EXPIRE)
c6a69271	77	struct spwd *spw;
7368a6c8	78
7368a6c8	79	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
c6a69271	80	if (!pw \|\| !pw->pw_name)
7368a6c8	81	return 0;
7368a6c8	82
4cb5ffa0	83	spw = getspnam(pw->pw_name);
27494968	84	if (spw != NULL) {
27494968	85	int days = time(NULL) / 86400;
4cb5ffa0	86
27494968	87	/* Check account expiry */
37c1c46d	88	if ((spw->sp_expire >= 0) && (days > spw->sp_expire))
27494968	89	return 0;
	90
	91	/* Check password expiry */
2b87da3b	92	if ((spw->sp_lstchg >= 0) && (spw->sp_max >= 0) &&
7f8f5e00	93	(days > (spw->sp_lstchg + spw->sp_max)))
27494968	94	return 0;
27494968	95	}
4cb5ffa0	96	#else
4cb5ffa0	97	/* Shouldn't be called if pw is NULL, but better safe than sorry... */
c6a69271	98	if (!pw \|\| !pw->pw_name)
4cb5ffa0	99	return 0;
	100	#endif
	101
301e9b01	102	/*
	103	* Get the shell from the password data. An empty shell field is
	104	* legal, and means /bin/sh.
	105	*/
	106	shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
	107
	108	/* deny if shell does not exists or is not executable */
b334badd	109	if (stat(shell, &st) != 0) {
	110	log("User %.100s not allowed because shell %.100s does not exist",
	111	pw->pw_name, shell);
7368a6c8	112	return 0;
b334badd	113	}
c390a3c8	114	if (S_ISREG(st.st_mode) == 0 \|\|
c390a3c8	115	(st.st_mode & (S_IXOTH\|S_IXUSR\|S_IXGRP)) == 0) {
b334badd	116	log("User %.100s not allowed because shell %.100s is not executable",
b334badd	117	pw->pw_name, shell);
7368a6c8	118	return 0;
b334badd	119	}
7368a6c8	120
6805fc56	121	if (options.num_deny_users > 0 \|\| options.num_allow_users > 0) {
	122	hostname = get_canonical_hostname(options.verify_reverse_mapping);
	123	ipaddr = get_remote_ipaddr();
	124	}
	125
7368a6c8	126	/* Return false if user is listed in DenyUsers */
7368a6c8	127	if (options.num_deny_users > 0) {
7368a6c8	128	for (i = 0; i < options.num_deny_users; i++)
762715ce	129	if (match_user(pw->pw_name, hostname, ipaddr,
b334badd	130	options.deny_users[i])) {
762715ce	131	log("User %.100s not allowed because listed in DenyUsers",
762715ce	132	pw->pw_name);
7368a6c8	133	return 0;
b334badd	134	}
7368a6c8	135	}
	136	/* Return false if AllowUsers isn't empty and user isn't listed there */
	137	if (options.num_allow_users > 0) {
7368a6c8	138	for (i = 0; i < options.num_allow_users; i++)
762715ce	139	if (match_user(pw->pw_name, hostname, ipaddr,
80f8f24f	140	options.allow_users[i]))
7368a6c8	141	break;
7368a6c8	142	/* i < options.num_allow_users iff we break for loop */
b334badd	143	if (i >= options.num_allow_users) {
	144	log("User %.100s not allowed because not listed in AllowUsers",
	145	pw->pw_name);
7368a6c8	146	return 0;
b334badd	147	}
7368a6c8	148	}
7368a6c8	149	if (options.num_deny_groups > 0 \|\| options.num_allow_groups > 0) {
c6a69271	150	/* Get the user's group access list (primary and supplementary) */
b334badd	151	if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
	152	log("User %.100s not allowed because not in any group",
	153	pw->pw_name);
7368a6c8	154	return 0;
b334badd	155	}
7368a6c8	156
c6a69271	157	/* Return false if one of user's groups is listed in DenyGroups */
	158	if (options.num_deny_groups > 0)
	159	if (ga_match(options.deny_groups,
	160	options.num_deny_groups)) {
	161	ga_free();
b334badd	162	log("User %.100s not allowed because a group is listed in DenyGroups",
b334badd	163	pw->pw_name);
7368a6c8	164	return 0;
c6a69271	165	}
7368a6c8	166	/*
c6a69271	167	* Return false if AllowGroups isn't empty and one of user's groups
7368a6c8	168	* isn't listed there
7368a6c8	169	*/
c6a69271	170	if (options.num_allow_groups > 0)
	171	if (!ga_match(options.allow_groups,
	172	options.num_allow_groups)) {
	173	ga_free();
b334badd	174	log("User %.100s not allowed because none of user's groups are listed in AllowGroups",
b334badd	175	pw->pw_name);
7368a6c8	176	return 0;
c6a69271	177	}
c6a69271	178	ga_free();
7368a6c8	179	}
	180
	181	#ifdef WITH_AIXAUTHENTICATE
5daf7064	182	if (loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &loginmsg) != 0) {
c1ef8333	183	if (loginmsg && *loginmsg) {
	184	/* Remove embedded newlines (if any) */
	185	char *p;
5daf7064	186	for (p = loginmsg; *p; p++) {
c1ef8333	187	if (*p == '\n')
c1ef8333	188	*p = ' ';
5daf7064	189	}
c1ef8333	190	/* Remove trailing newline */
c1ef8333	191	*--p = '\0';
5daf7064	192	log("Login restricted for %s: %.100s", pw->pw_name, loginmsg);
c1ef8333	193	}
7368a6c8	194	return 0;
c1ef8333	195	}
7368a6c8	196	#endif /* WITH_AIXAUTHENTICATE */
	197
	198	/* We found no reason not to let this user try to log on... */
	199	return 1;
	200	}
59c97189	201
	202	Authctxt *
	203	authctxt_new(void)
	204	{
2b87da3b	205	Authctxt authctxt = xmalloc(sizeof(authctxt));
	206	memset(authctxt, 0, sizeof(*authctxt));
	207	return authctxt;
59c97189	208	}
59c97189	209
59c97189	210	void
	211	auth_log(Authctxt authctxt, int authenticated, char method, char *info)
	212	{
	213	void (authlog) (const char fmt,...) = verbose;
	214	char *authmsg;
	215
	216	/* Raise logging level */
	217	if (authenticated == 1 \|\|
	218	!authctxt->valid \|\|
	219	authctxt->failures >= AUTH_FAIL_LOG \|\|
	220	strcmp(method, "password") == 0)
	221	authlog = log;
	222
	223	if (authctxt->postponed)
	224	authmsg = "Postponed";
	225	else
	226	authmsg = authenticated ? "Accepted" : "Failed";
	227
	228	authlog("%s %s for %s%.100s from %.200s port %d%s",
	229	authmsg,
	230	method,
	231	authctxt->valid ? "" : "illegal user ",
fad3754c	232	authctxt->user,
59c97189	233	get_remote_ipaddr(),
	234	get_remote_port(),
	235	info);
	236	}
	237
	238	/*
15853e93	239	* Check whether root logins are disallowed.
59c97189	240	*/
59c97189	241	int
15853e93	242	auth_root_allowed(char *method)
59c97189	243	{
15853e93	244	switch (options.permit_root_login) {
15853e93	245	case PERMIT_YES:
59c97189	246	return 1;
15853e93	247	break;
	248	case PERMIT_NO_PASSWD:
	249	if (strcmp(method, "password") != 0)
	250	return 1;
	251	break;
	252	case PERMIT_FORCED_ONLY:
	253	if (forced_command) {
	254	log("Root login accepted for forced command.");
	255	return 1;
	256	}
	257	break;
59c97189	258	}
15853e93	259	log("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
15853e93	260	return 0;
59c97189	261	}
c8445989	262
	263
	264	/*
	265	* Given a template and a passwd structure, build a filename
	266	* by substituting % tokenised options. Currently, %% becomes '%',
	267	* %h becomes the home directory and %u the username.
	268	*
	269	* This returns a buffer allocated by xmalloc.
	270	*/
	271	char *
	272	expand_filename(const char filename, struct passwd pw)
	273	{
	274	Buffer buffer;
	275	char *file;
	276	const char *cp;
	277
	278	/*
	279	* Build the filename string in the buffer by making the appropriate
	280	* substitutions to the given file name.
	281	*/
	282	buffer_init(&buffer);
	283	for (cp = filename; *cp; cp++) {
	284	if (cp[0] == '%' && cp[1] == '%') {
	285	buffer_append(&buffer, "%", 1);
	286	cp++;
	287	continue;
	288	}
	289	if (cp[0] == '%' && cp[1] == 'h') {
	290	buffer_append(&buffer, pw->pw_dir, strlen(pw->pw_dir));
	291	cp++;
	292	continue;
	293	}
	294	if (cp[0] == '%' && cp[1] == 'u') {
	295	buffer_append(&buffer, pw->pw_name,
184eed6a	296	strlen(pw->pw_name));
c8445989	297	cp++;
	298	continue;
	299	}
	300	buffer_append(&buffer, cp, 1);
	301	}
	302	buffer_append(&buffer, "\0", 1);
	303
	304	/*
	305	* Ensure that filename starts anchored. If not, be backward
	306	* compatible and prepend the '%h/'
	307	*/
	308	file = xmalloc(MAXPATHLEN);
	309	cp = buffer_ptr(&buffer);
	310	if (*cp != '/')
	311	snprintf(file, MAXPATHLEN, "%s/%s", pw->pw_dir, cp);
	312	else
	313	strlcpy(file, cp, MAXPATHLEN);
	314
	315	buffer_free(&buffer);
	316	return file;
	317	}
	318
	319	char *
	320	authorized_keys_file(struct passwd *pw)
	321	{
	322	return expand_filename(options.authorized_keys_file, pw);
	323	}
	324
	325	char *
	326	authorized_keys_file2(struct passwd *pw)
	327	{
	328	return expand_filename(options.authorized_keys_file2, pw);
	329	}
	330
d0c8ca5c	331	/* return ok if key exists in sysfile or userfile */
	332	HostStatus
	333	check_key_in_hostfiles(struct passwd pw, Key key, const char *host,
	334	const char sysfile, const char userfile)
	335	{
	336	Key *found;
	337	char *user_hostfile;
	338	struct stat st;
17a3011c	339	HostStatus host_status;
d0c8ca5c	340
	341	/* Check if we know the host and its host key. */
	342	found = key_new(key->type);
	343	host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
	344
	345	if (host_status != HOST_OK && userfile != NULL) {
	346	user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
	347	if (options.strict_modes &&
	348	(stat(user_hostfile, &st) == 0) &&
	349	((st.st_uid != 0 && st.st_uid != pw->pw_uid) \|\|
184eed6a	350	(st.st_mode & 022) != 0)) {
d0c8ca5c	351	log("Authentication refused for %.100s: "
	352	"bad owner or modes for %.200s",
	353	pw->pw_name, user_hostfile);
	354	} else {
	355	temporarily_use_uid(pw);
	356	host_status = check_host_in_hostfile(user_hostfile,
	357	host, key, found, NULL);
	358	restore_uid();
	359	}
	360	xfree(user_hostfile);
	361	}
	362	key_free(found);
	363
	364	debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
	365	"ok" : "not found", host);
	366	return host_status;
	367	}
	368
	369
c8445989	370	/*
	371	* Check a given file for security. This is defined as all components
	372	* of the path to the file must either be owned by either the owner of
1ddf764b	373	* of the file or root and no directories must be group or world writable.
c8445989	374	*
	375	* XXX Should any specific check be done for sym links ?
	376	*
	377	* Takes an open file descriptor, the file name, a uid and and
	378	* error buffer plus max size as arguments.
	379	*
	380	* Returns 0 on success and -1 on failure
	381	*/
	382	int
6978866a	383	secure_filename(FILE f, const char file, struct passwd *pw,
6978866a	384	char *err, size_t errlen)
c8445989	385	{
6978866a	386	uid_t uid = pw->pw_uid;
76fbdd47	387	char buf[MAXPATHLEN], homedir[MAXPATHLEN];
c8445989	388	char *cp;
	389	struct stat st;
	390
	391	if (realpath(file, buf) == NULL) {
	392	snprintf(err, errlen, "realpath %s failed: %s", file,
	393	strerror(errno));
	394	return -1;
	395	}
76fbdd47	396	if (realpath(pw->pw_dir, homedir) == NULL) {
	397	snprintf(err, errlen, "realpath %s failed: %s", pw->pw_dir,
	398	strerror(errno));
	399	return -1;
	400	}
c8445989	401
	402	/* check the open file to avoid races */
	403	if (fstat(fileno(f), &st) < 0 \|\|
	404	(st.st_uid != 0 && st.st_uid != uid) \|\|
	405	(st.st_mode & 022) != 0) {
	406	snprintf(err, errlen, "bad ownership or modes for file %s",
	407	buf);
	408	return -1;
	409	}
	410
	411	/* for each component of the canonical path, walking upwards */
	412	for (;;) {
	413	if ((cp = dirname(buf)) == NULL) {
	414	snprintf(err, errlen, "dirname() failed");
	415	return -1;
	416	}
	417	strlcpy(buf, cp, sizeof(buf));
	418
	419	debug3("secure_filename: checking '%s'", buf);
	420	if (stat(buf, &st) < 0 \|\|
	421	(st.st_uid != 0 && st.st_uid != uid) \|\|
	422	(st.st_mode & 022) != 0) {
184eed6a	423	snprintf(err, errlen,
c8445989	424	"bad ownership or modes for directory %s", buf);
	425	return -1;
	426	}
	427
afd501f9	428	/* If are passed the homedir then we can stop */
76fbdd47	429	if (strcmp(homedir, buf) == 0) {
afd501f9	430	debug3("secure_filename: terminating check at '%s'",
	431	buf);
	432	break;
	433	}
c8445989	434	/*
	435	* dirname should always complete with a "/" path,
	436	* but we can be paranoid and check for "." too
	437	*/
	438	if ((strcmp("/", buf) == 0) \|\| (strcmp(".", buf) == 0))
	439	break;
	440	}
	441	return 0;
	442	}
443fa1cd	443
	444	struct passwd *
	445	getpwnamallow(const char *user)
	446	{
1836f69f	447	#ifdef HAVE_LOGIN_CAP
	448	extern login_cap_t *lc;
	449	#ifdef BSD_AUTH
	450	auth_session_t *as;
	451	#endif
	452	#endif
443fa1cd	453	struct passwd *pw;
	454
	455	pw = getpwnam(user);
1836f69f	456	if (pw == NULL \|\| !allowed_user(pw))
	457	return (NULL);
	458	#ifdef HAVE_LOGIN_CAP
	459	if ((lc = login_getclass(pw->pw_class)) == NULL) {
	460	debug("unable to get login class: %s", user);
	461	return (NULL);
	462	}
	463	#ifdef BSD_AUTH
	464	if ((as = auth_open()) == NULL \|\| auth_setpwd(as, pw) != 0 \|\|
	465	auth_approval(NULL, lc, pw->pw_name, "ssh") <= 0) {
	466	debug("Approval failure for %s", user);
443fa1cd	467	pw = NULL;
1836f69f	468	}
	469	if (as != NULL)
	470	auth_close(as);
	471	#endif
	472	#endif
06bea668	473	if (pw != NULL)
	474	return (pwcopy(pw));
	475	return (NULL);
443fa1cd	476	}