Hello Apache developers,
Unfortunately I think you need to pick an awkward name here so it
cannot be confused/misused. Like "forward-dns"
Attached is a patch against the sources, including a documentation,
which use the syntax "Require forward-dns foo.apache.org".
The second file is the same extension as an external module, for easy
testing. The only difference with the integrated version is the error
messages text which are given the function name instead of en APLOGNO, and
the absence of documentation.
I'm proposing to commit the patch if I'm given a go.
Vote?
--
Fabien.
Index: docs/log-message-tags/next-number
===================================================================
--- docs/log-message-tags/next-number (revision 1733559)
+++ docs/log-message-tags/next-number (working copy)
@@ -1 +1 @@
-3354
+3357
Index: docs/manual/mod/mod_authz_host.xml
===================================================================
--- docs/manual/mod/mod_authz_host.xml (revision 1733559)
+++ docs/manual/mod/mod_authz_host.xml (working copy)
@@ -58,7 +58,8 @@
<p>Apache's <directive module="mod_authz_core">Require</directive>
directive is used during the authorization phase to ensure that a user is allowed or
denied access to a resource. mod_authz_host extends the
- authorization types with <code>ip</code>, <code>host</code> and <code>local</code>.
+ authorization types with <code>ip</code>, <code>host</code>,
+ <code>forward-dns</code> and <code>local</code>.
Other authorization types may also be
used but may require that additional authorization modules be loaded.</p>
@@ -157,6 +158,29 @@
</section>
+<section id="reqfwddns"><title>Require forward-dns</title>
+
+ <p>The <code>forward-dns</code> provider allows access to the server
+ to be controlled based on simple host names. When
+ <code>Require forward-dns <var>host-name</var></code> is specified,
+ all IP addresses corresponding to <code><var>host-name<var></code>
+ are allowed access.</p>
+
+ <p>In contrast to the <code>host</code> provider, this provider does not
+ rely on reverse DNS lookups: it simply queries the DNS for the host name
+ and allows a client if its IP matches. As a consequence, it will only
+ work with host names, not domain names. However, as the reverse DNS is
+ not used, it will work with clients which use a dynamic DNS service.</p>
+
+ <highlight language="config">
+Require forward-dns bla.example.org
+ </highlight>
+
+ <p>A client the IP of which is resolved from the name
+ <code>bla.example.org</code> will be granted access.</p>
+
+</section>
+
<section id="reqlocal"><title>Require local</title>
<p>The <code>local</code> provider allows access to the server if any
Index: modules/aaa/mod_authz_host.c
===================================================================
--- modules/aaa/mod_authz_host.c (revision 1733559)
+++ modules/aaa/mod_authz_host.c (working copy)
@@ -216,6 +216,71 @@
return AUTHZ_DENIED;
}
+static authz_status
+forward_dns_check_authorization(request_rec *r,
+ const char *require_line,
+ const void *parsed_require_line)
+{
+ const char *err = NULL;
+ const ap_expr_info_t *expr = parsed_require_line;
+ const char *require, *t;
+ char *w;
+
+ /* the require line is an expression, which is evaluated now. */
+ require = ap_expr_str_exec(r, expr, &err);
+ if (err) {
+ ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(03354)
+ "Can't evaluate require expression: %s", err);
+ return AUTHZ_DENIED;
+ }
+
+ /* tokenize expected list of names */
+ t = require;
+ while ((w = ap_getword_conf(r->pool, &t)) && w[0]) {
+
+ apr_sockaddr_t *sa;
+ apr_status_t rv;
+ char *hash_ptr;
+
+ /* stop on apache configuration file comments */
+ if ((hash_ptr = ap_strchr(w, '#'))) {
+ if (hash_ptr == w) {
+ break;
+ }
+ *hash_ptr = '\0';
+ }
+
+ /* does the client ip match one of the names? */
+ rv = apr_sockaddr_info_get(&sa, w, APR_UNSPEC, 0, 0, r->pool);
+ if (rv == APR_SUCCESS) {
+
+ while (sa) {
+ int match = apr_sockaddr_equal(sa, r->useragent_addr);
+
+ ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(03355)
+ "access check for %s as '%s': %s",
+ r->useragent_ip, w, match? "yes": "no");
+ if (match) {
+ return AUTHZ_GRANTED;
+ }
+
+ sa = sa->next;
+ }
+ }
+ else {
+ ap_log_rerror(APLOG_MARK, APLOG_WARNING, 0, r, APLOGNO(03356)
+ "No sockaddr info for \"%s\"", w);
+ }
+
+ /* stop processing, we are in a comment */
+ if (hash_ptr) {
+ break;
+ }
+ }
+
+ return AUTHZ_DENIED;
+}
+
static authz_status local_check_authorization(request_rec *r,
const char *require_line,
const void *parsed_require_line)
@@ -265,6 +330,12 @@
&host_parse_config,
};
+static const authz_provider authz_forward_dns_provider =
+{
+ &forward_dns_check_authorization,
+ &host_parse_config,
+};
+
static const authz_provider authz_local_provider =
{
&local_check_authorization,
@@ -309,6 +380,10 @@
ap_register_auth_provider(p, AUTHZ_PROVIDER_GROUP, "host",
AUTHZ_PROVIDER_VERSION,
&authz_host_provider, AP_AUTH_INTERNAL_PER_CONF);
+ ap_register_auth_provider(p, AUTHZ_PROVIDER_GROUP, "forward-dns",
+ AUTHZ_PROVIDER_VERSION,
+ &authz_forward_dns_provider,
+ AP_AUTH_INTERNAL_PER_CONF);
ap_register_auth_provider(p, AUTHZ_PROVIDER_GROUP, "local",
AUTHZ_PROVIDER_VERSION,
&authz_local_provider, AP_AUTH_INTERNAL_PER_CONF);
/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* Security options etc.
*
* Module derived from code originally written by Rob McCool
*
*/
#include "apr_strings.h"
#include "apr_network_io.h"
#include "apr_md5.h"
#include "apr_hash.h"
#define APR_WANT_STRFUNC
#define APR_WANT_BYTEFUNC
#include "apr_want.h"
#include "ap_config.h"
#include "ap_provider.h"
#include "httpd.h"
#include "http_core.h"
#include "http_config.h"
#include "http_log.h"
#include "http_protocol.h"
#include "http_request.h"
#include "mod_auth.h"
#if APR_HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
static authz_status
forward_dns_check_authorization(request_rec *r,
const char *require_line,
const void *parsed_require_line)
{
const char *err = NULL;
const ap_expr_info_t *expr = parsed_require_line;
const char *require, *t;
char *w;
/* the require line is an expression, which is evaluated now. */
require = ap_expr_str_exec(r, expr, &err);
if (err) {
ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, // APLOGNO(FIXME)
"forward_dns_check_authorization: "
"Can't evaluate require expression: %s", err);
return AUTHZ_DENIED;
}
/* tokenize expected list of names */
t = require;
while ((w = ap_getword_conf(r->pool, &t)) && w[0]) {
apr_sockaddr_t *sa;
apr_status_t rv;
char *hash_ptr;
/* stop on apache configuration file comments */
if ((hash_ptr = ap_strchr(w, '#'))) {
if (hash_ptr == w) {
break;
}
*hash_ptr = '\0';
}
/* does the client ip match one of the names? */
rv = apr_sockaddr_info_get(&sa, w, APR_UNSPEC, 0, 0, r->pool);
if (rv == APR_SUCCESS) {
while (sa) {
int match = apr_sockaddr_equal(sa, r->useragent_addr);
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, // APLOGNO(FIXME)
"forward_dns_check_authorization" // __func__
": %s for %s: %s",
w, r->useragent_ip, match? "yes": "no");
if (match) {
return AUTHZ_GRANTED;
}
sa = sa->next;
}
}
else {
ap_log_rerror(APLOG_MARK, APLOG_WARNING, 0, r, // APLOGNO(FIXME)
"forward_dns_check_authorization" // __func__
": no sockaddr info for \"%s\"", w);
}
/* stop processing, we are in a comment */
if (hash_ptr) {
break;
}
}
return AUTHZ_DENIED;
}
/* copy of host_parse_config */
static const char *host_parse_config(cmd_parms *cmd, const char *require_line,
const void **parsed_require_line)
{
const char *expr_err = NULL;
ap_expr_info_t *expr;
expr = ap_expr_parse_cmd(cmd, require_line, AP_EXPR_FLAG_STRING_RESULT,
&expr_err, NULL);
if (expr_err)
return apr_pstrcat(cmd->temp_pool,
"Cannot parse expression in require line: ",
expr_err, NULL);
*parsed_require_line = expr;
return NULL;
}
static const authz_provider authz_forward_dns_provider =
{
&forward_dns_check_authorization,
&host_parse_config,
};
static void register_hooks(apr_pool_t *p)
{
ap_register_auth_provider(p, AUTHZ_PROVIDER_GROUP, "forward-dns",
AUTHZ_PROVIDER_VERSION,
&authz_forward_dns_provider,
AP_AUTH_INTERNAL_PER_CONF);
}
AP_DECLARE_MODULE(authz_forward_dns) =
{
STANDARD20_MODULE_STUFF,
NULL, /* dir config creater */
NULL, /* dir merger --- default is to override */
NULL, /* server config */
NULL, /* merge server config */
NULL,
register_hooks /* register hooks */
};
