1 files changed, 158 insertions, 0 deletions
diff --git a/modules/aaa/mod_allowmethods.c b/modules/aaa/mod_allowmethods.c
new file mode 100644
index 0000000..dd41196
--- /dev/null
+++ b/modules/aaa/mod_allowmethods.c
@@ -0,0 +1,158 @@
+/* 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;
+    apr_int64_t allowed;
+} 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->allowed == 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 = 0;
+    conf->allowed_set = 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->allowed = add->allowed;
+        conf->allowed_set = add->allowed_set;
+    }
+    else {
+        conf->allowed = base->allowed;
+        conf->allowed_set = base->allowed_set;
+    }
+
+    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;
+
+    if (argc == 0) {
+        return "AllowMethods: No method or 'reset' keyword given";
+    }
+    if (argc == 1) {
+        if (strcasecmp("reset", argv[0]) == 0) {
+            conf->allowed = 0;
+            conf->allowed_set = 1;
+            return NULL;
+        }
+    }
+
+    for (i = 0; i < argc; i++) {
+        int m;
+
+        m = ap_method_number_of(argv[i]);
+        if (m == M_INVALID) {
+            return apr_pstrcat(cmd->pool, "AllowMethods: Invalid Method '",
+                               argv[i], "'", NULL);
+        }
+
+        conf->allowed |= (AP_METHOD_BIT << m);
+    }
+    conf->allowed_set = 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,
+};