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/* 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.
*/
#include "httpd.h"
#include "http_core.h"
#include "http_config.h"
#include "http_protocol.h"
#include "http_request.h"
#include "http_log.h"
#include "apr_strings.h"
/**
* This module makes it easy to restrict what HTTP methods can be ran against
* a server.
*
* It provides one command:
* AllowMethods
* This command takes a list of HTTP methods to allow.
*
* The most common configuration should be like this:
* <Directory />
* AllowMethods GET HEAD OPTIONS
* </Directory>
* <Directory /special/cgi-bin>
* AllowMethods GET HEAD OPTIONS POST
* </Directory>
* Non-matching methods will be returned a status 405 (method not allowed)
*
* To allow all methods, and effectively turn off mod_allowmethods, use:
* AllowMethods reset
*/
typedef struct am_conf_t {
int allowed_set; /* AllowMethods has been set/changed flag */
int enforce_methods; /* Enforce AllowMethods flag */
ap_method_mask_t add; /* Methods Added by +METHOD mask */
ap_method_mask_t remove; /* Methods Removed by -METHOD mask */
ap_method_mask_t allowed; /* Allowed Methods mask */
} am_conf_t;
module AP_MODULE_DECLARE_DATA allowmethods_module;
static int am_check_access(request_rec *r)
{
int method = r->method_number;
am_conf_t *conf;
conf = (am_conf_t *) ap_get_module_config(r->per_dir_config,
&allowmethods_module);
if (!conf || conf->enforce_methods == 0) {
return DECLINED;
}
r->allowed = conf->allowed;
if (conf->allowed & (AP_METHOD_BIT << method)) {
return DECLINED;
}
ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01623)
"client method denied by server configuration: '%s' to %s%s",
r->method,
r->filename ? "" : "uri ",
r->filename ? r->filename : r->uri);
return HTTP_METHOD_NOT_ALLOWED;
}
static void *am_create_conf(apr_pool_t *p, char *dummy)
{
am_conf_t *conf = apr_pcalloc(p, sizeof(am_conf_t));
conf->allowed = INT_MAX;
conf->allowed_set = 0;
conf->add = 0;
conf->remove = 0;
conf->enforce_methods = 0;
return conf;
}
static void *am_merge_conf(apr_pool_t *pool, void *a, void *b)
{
am_conf_t *base = (am_conf_t *)a;
am_conf_t *add = (am_conf_t *)b;
am_conf_t *conf = apr_palloc(pool, sizeof(am_conf_t));
if (add->allowed_set) {
conf->add = 0;
conf->remove = 0;
/* Add/Remove AllowedMethods set with + or - */
if( add->add || add->remove ) {
conf->allowed = base->allowed | add->allowed;
if( add->add ) {
conf->allowed |= add->add;
}
if( add->remove ) {
conf->allowed &= ~(add->remove);
}
conf->enforce_methods = 1;
conf->allowed_set = 1;
}
/* Straightforward AllowMethods settings, just set it */
else
{
conf->allowed = add->allowed;
conf->allowed_set = add->allowed_set;
conf->enforce_methods = add->enforce_methods;
}
}
else {
conf->allowed = base->allowed;
conf->add = base->add;
conf->remove = base->remove;
conf->allowed_set = base->allowed_set;
conf->enforce_methods = base->enforce_methods;
}
return conf;
}
static const char *am_allowmethods(cmd_parms *cmd, void *d, int argc,
char *const argv[])
{
int i;
am_conf_t *conf = (am_conf_t *)d;
int merge = 0;
int first = 1;
char *method;
char action = '\0';
if (argc == 0) {
return "AllowMethods: No method or 'reset' keyword given";
}
if (argc == 1) {
if (!ap_cstr_casecmp(argv[0], "reset")) {
conf->allowed = 0;
conf->enforce_methods = 0;
conf->add = 0;
conf->remove = 0;
conf->allowed_set = 1;
return NULL;
}
}
conf->allowed = 0;
conf->add = 0;
conf->remove = 0;
for (i = 0; i < argc; i++) {
int m;
char *w = argv[i];
if( *w == '-' || *w == '+' ) {
if (!merge && !first) {
return "Either all methods in AllowMethods must start with + or -, or no methods may.";
}
action = *(w++);
method = w;
merge = 1;
}
else if (merge) {
return "Either all methods in AllowMethods must start with + or -, or no methods may.";
}
else {
method = w;
}
m = ap_method_number_of((char const*)method);
if (m == M_INVALID) {
return apr_pstrcat(cmd->pool, "AllowMethods: Invalid Method '",
method, "'", NULL);
}
if (action == '-' ) {
conf->remove |= (AP_METHOD_BIT << m);
conf->add &= ~(AP_METHOD_BIT << m);
conf->allowed &= ~(AP_METHOD_BIT << m);
}
else if (action == '+' ) {
conf->remove &= ~(AP_METHOD_BIT << m);
conf->add |= (AP_METHOD_BIT << m);
conf->allowed |= (AP_METHOD_BIT << m);
}
else {
conf->allowed |= (AP_METHOD_BIT << m);
}
first = 0;
}
conf->allowed_set = 1;
conf->enforce_methods = 1;
return NULL;
}
static void am_register_hooks(apr_pool_t * p)
{
ap_hook_access_checker(am_check_access, NULL, NULL, APR_HOOK_REALLY_FIRST);
}
static const command_rec am_cmds[] = {
AP_INIT_TAKE_ARGV("AllowMethods", am_allowmethods, NULL,
ACCESS_CONF,
"only allow specific methods"),
{NULL}
};
AP_DECLARE_MODULE(allowmethods) = {
STANDARD20_MODULE_STUFF,
am_create_conf,
am_merge_conf,
NULL,
NULL,
am_cmds,
am_register_hooks,
};
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