267 lines
7.1 KiB
C
267 lines
7.1 KiB
C
/* $NetBSD: auth.c,v 1.5 2001/04/10 08:07:54 itojun Exp $ */
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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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#include "includes.h"
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RCSID("$OpenBSD: auth.c,v 1.21 2001/03/19 17:07:23 markus Exp $");
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#include "xmalloc.h"
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#include "match.h"
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#include "groupaccess.h"
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#include "log.h"
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#include "servconf.h"
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#include "auth.h"
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#include "auth-options.h"
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#include "canohost.h"
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#ifdef HAVE_LOGIN_CAP
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#include <login_cap.h>
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#endif
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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
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* in DenyUsers or one of user's groups is listed in DenyGroups, false
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* will be returned. If AllowUsers isn't empty and user isn't listed
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* there, or if AllowGroups isn't empty and one of user's groups isn't
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* listed there, false will be 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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char *shell;
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int i;
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#ifdef HAVE_LOGIN_CAP
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int 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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#endif
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/* Shouldn't be called if pw is NULL, but better safe than sorry... */
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if (!pw || !pw->pw_name)
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return 0;
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#ifdef HAVE_LOGIN_CAP
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hostname = get_canonical_hostname(1);
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ipaddr = get_remote_ipaddr();
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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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return 0;
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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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return 0;
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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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return 0;
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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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return 0;
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}
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}
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login_close(lc);
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#endif
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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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return 0;
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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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return 0;
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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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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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return 0;
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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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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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return 0;
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}
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if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
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/* Get the user's group access list (primary and supplementary) */
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if (ga_init(pw->pw_name, pw->pw_gid) == 0)
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return 0;
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/* Return false if one of user's groups is listed in DenyGroups */
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if (options.num_deny_groups > 0)
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if (ga_match(options.deny_groups,
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options.num_deny_groups)) {
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ga_free();
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return 0;
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}
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/*
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* Return false if AllowGroups isn't empty and one of user's groups
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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 (!ga_match(options.allow_groups,
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options.num_allow_groups)) {
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ga_free();
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return 0;
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}
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ga_free();
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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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}
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Authctxt *
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authctxt_new(void)
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{
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Authctxt *authctxt = xmalloc(sizeof(*authctxt));
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memset(authctxt, 0, sizeof(*authctxt));
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return authctxt;
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}
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void
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auth_log(Authctxt *authctxt, int authenticated, char *method, char *info)
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{
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void (*authlog) (const char *fmt,...) = verbose;
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char *authmsg;
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/* Raise logging level */
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if (authenticated == 1 ||
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!authctxt->valid ||
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authctxt->failures >= AUTH_FAIL_LOG ||
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strcmp(method, "password") == 0)
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authlog = log;
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if (authctxt->postponed)
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authmsg = "Postponed";
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else
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authmsg = authenticated ? "Accepted" : "Failed";
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authlog("%s %s for %s%.100s from %.200s port %d%s",
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authmsg,
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method,
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authctxt->valid ? "" : "illegal user ",
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authctxt->valid && authctxt->pw->pw_uid == 0 ? "ROOT" : authctxt->user,
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get_remote_ipaddr(),
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get_remote_port(),
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info);
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}
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/*
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* Check whether root logins are disallowed.
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*/
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int
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auth_root_allowed(char *method)
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{
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switch (options.permit_root_login) {
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case PERMIT_YES:
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return 1;
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break;
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case PERMIT_NO_PASSWD:
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if (strcmp(method, "password") != 0)
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return 1;
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break;
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case PERMIT_FORCED_ONLY:
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if (forced_command) {
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log("Root login accepted for forced command.");
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return 1;
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}
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break;
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}
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log("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
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return 0;
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}
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