283 lines
8.9 KiB
C
283 lines
8.9 KiB
C
/* $NetBSD: auth.c,v 1.1.1.1 2000/09/28 22:09:41 thorpej Exp $ */
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/*-
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* Copyright (c) 2000 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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* All rights reserved
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*
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* As far as I am concerned, the code I have written for this software
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* can be used freely for any purpose. Any derived versions of this
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* software must be clearly marked as such, and if the derived work is
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* incompatible with the protocol description in the RFC file, it must be
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* called by a name other than "ssh" or "Secure Shell".
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*
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*
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* Copyright (c) 2000 Markus Friedl. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/* from OpenBSD: auth.c,v 1.10 2000/09/07 21:13:36 markus Exp */
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#include <sys/cdefs.h>
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#ifndef lint
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__RCSID("$NetBSD: auth.c,v 1.1.1.1 2000/09/28 22:09:41 thorpej Exp $");
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#endif
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#include "includes.h"
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#include "xmalloc.h"
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#include "rsa.h"
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#include "ssh.h"
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#include "pty.h"
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#include "packet.h"
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#include "buffer.h"
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#include "cipher.h"
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#include "mpaux.h"
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#include "servconf.h"
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#include "compat.h"
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#include "channels.h"
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#include "match.h"
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#include "bufaux.h"
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#include "ssh2.h"
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#include "auth.h"
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#include "session.h"
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#include <login_cap.h>
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/* import */
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extern ServerOptions options;
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/*
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* Check if the user is allowed to log in via ssh. If user is listed in
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* DenyUsers or user's primary group is listed in DenyGroups, false will
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* be returned. If AllowUsers isn't empty and user isn't listed there, or
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* if AllowGroups isn't empty and user isn't listed there, false will be
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* returned.
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* If the user's shell is not executable, false will be returned.
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* Otherwise true is returned.
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*/
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int
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allowed_user(struct passwd *pw)
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{
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struct stat st;
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struct group *grp;
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const char *shell;
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int i, match_name, match_ip;
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login_cap_t *lc;
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const char *hostname, *ipaddr;
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char *cap_hlist, *hp;
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hostname = get_canonical_hostname();
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ipaddr = get_remote_ipaddr();
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/* Shouldn't be called if pw is NULL, but better safe than sorry... */
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if (pw == NULL)
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goto denied;
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lc = login_getclass(pw->pw_class);
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/*
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* Check the deny list.
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*/
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cap_hlist = login_getcapstr(lc, "host.deny", NULL, NULL);
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if (cap_hlist != NULL) {
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hp = strtok(cap_hlist, ",");
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while (hp != NULL) {
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match_name = match_hostname(hostname,
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hp, strlen(hp));
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match_ip = match_hostname(ipaddr,
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hp, strlen(hp));
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/*
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* Only a positive match here causes a "deny".
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*/
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if (match_name > 0 || match_ip > 0) {
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free(cap_hlist);
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login_close(lc);
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goto denied;
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}
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hp = strtok(NULL, ",");
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}
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free(cap_hlist);
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}
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/*
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* Check the allow list. If the allow list exists, and the
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* remote host is not in it, the user is implicitly denied.
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*/
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cap_hlist = login_getcapstr(lc, "host.allow", NULL, NULL);
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if (cap_hlist != NULL) {
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hp = strtok(cap_hlist, ",");
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if (hp == NULL) {
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/* Just in case there's an empty string... */
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free(cap_hlist);
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login_close(lc);
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goto denied;
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}
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while (hp != NULL) {
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match_name = match_hostname(hostname,
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hp, strlen(hp));
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match_ip = match_hostname(ipaddr,
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hp, strlen(hp));
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/*
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* Negative match causes an immediate "deny".
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* Positive match causes us to break out
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* of the loop (allowing a fallthrough).
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*/
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if (match_name < 0 || match_ip < 0) {
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free(cap_hlist);
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login_close(lc);
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goto denied;
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}
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if (match_name > 0 || match_ip > 0)
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break;
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}
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free(cap_hlist);
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if (hp == NULL) {
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login_close(lc);
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goto denied;
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}
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}
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login_close(lc);
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/*
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* Get the shell from the password data. An empty shell field is
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* legal, and means /bin/sh.
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*/
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shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
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/*
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* Deny if shell does not exists or is not executable.
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* XXX Should check to see if it is executable by the
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* XXX requesting user. --thorpej
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*/
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if (stat(shell, &st) != 0)
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goto denied;
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if (S_ISREG(st.st_mode) == 0 ||
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(st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0)
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goto denied;
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/*
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* XXX Consider nuking {Allow,Deny}{Users,Groups}. We have the
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* XXX login_cap(3) mechanism which covers all other types of
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* XXX logins, too.
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*/
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/* Return false if user is listed in DenyUsers */
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if (options.num_deny_users > 0) {
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if (pw->pw_name == NULL)
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goto denied;
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for (i = 0; i < options.num_deny_users; i++)
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if (match_pattern(pw->pw_name, options.deny_users[i]))
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goto denied;
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}
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/* Return false if AllowUsers isn't empty and user isn't listed there */
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if (options.num_allow_users > 0) {
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if (pw->pw_name == NULL)
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goto denied;
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for (i = 0; i < options.num_allow_users; i++)
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if (match_pattern(pw->pw_name, options.allow_users[i]))
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break;
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/* i < options.num_allow_users iff we break for loop */
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if (i >= options.num_allow_users)
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goto denied;
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}
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/* Get the primary group name if we need it. Return false if it fails */
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if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
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grp = getgrgid(pw->pw_gid);
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if (grp == NULL)
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goto denied;
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/* Return false if user's group is listed in DenyGroups */
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if (options.num_deny_groups > 0) {
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if (grp->gr_name == NULL)
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goto denied;
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for (i = 0; i < options.num_deny_groups; i++)
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if (match_pattern(grp->gr_name,
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options.deny_groups[i]))
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goto denied;
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}
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/*
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* Return false if AllowGroups isn't empty and user's group
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* isn't listed there
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*/
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if (options.num_allow_groups > 0) {
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if (grp->gr_name == NULL)
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goto denied;
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for (i = 0; i < options.num_allow_groups; i++)
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if (match_pattern(grp->gr_name,
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options.allow_groups[i]))
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break;
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/* i < options.num_allow_groups iff we break for
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loop */
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if (i >= options.num_allow_groups)
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goto denied;
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}
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}
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/* We found no reason not to let this user try to log on... */
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return 1;
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denied:
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/* XXX Need to add notice() --thorpej */
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log("Denied connection for %.200s from %.200s [%.200s] port %d.\n",
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pw == NULL ? "<unknown>" : pw->pw_name, hostname, ipaddr,
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get_remote_port());
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return (0);
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}
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