text: /* 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 "apr_strings.h"
  #include "apr_file_info.h"
  #include "apr_user.h"
  
  #include "ap_config.h"
  #include "ap_provider.h"
  #include "httpd.h"
  #include "http_config.h"
  #include "http_core.h"
  #include "http_log.h"
  #include "http_protocol.h"
  #include "http_request.h"
  
  #include "mod_auth.h"
  
  APR_DECLARE_OPTIONAL_FN(char*, authz_owner_get_file_group, (request_rec *r));
  
  static const command_rec authz_owner_cmds[] =
  {
      {NULL}
  };
  
  module AP_MODULE_DECLARE_DATA authz_owner_module;
  
  static authz_status fileowner_check_authorization(request_rec *r,
                                                    const char *require_args,
                                                    const void *parsed_require_args)
  {
      char *reason = NULL;
      apr_status_t status = 0;
  
  #if !APR_HAS_USER
      reason = "'Require file-owner' is not supported on this platform.";
      ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, APLOGNO(01632)
                    "Authorization of user %s to access %s failed, reason: %s",
                    r->user, r->uri, reason ? reason : "unknown");
      return AUTHZ_DENIED;
  #else  /* APR_HAS_USER */
      char *owner = NULL;
      apr_finfo_t finfo;
  
      if (!r->user) {
          return AUTHZ_DENIED_NO_USER;
      }
  
      if (!r->filename) {
          reason = "no filename available";
          ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, APLOGNO(01633)
                        "Authorization of user %s to access %s failed, reason: %s",
                        r->user, r->uri, reason ? reason : "unknown");
          return AUTHZ_DENIED;
      }
  
      status = apr_stat(&finfo, r->filename, APR_FINFO_USER, r->pool);
      if (status != APR_SUCCESS) {
          reason = apr_pstrcat(r->pool, "could not stat file ",
                                  r->filename, NULL);
          ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, APLOGNO(01634)
                        "Authorization of user %s to access %s failed, reason: %s",
                        r->user, r->uri, reason ? reason : "unknown");
          return AUTHZ_DENIED;
      }
  
      if (!(finfo.valid & APR_FINFO_USER)) {
          reason = "no file owner information available";
          ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, APLOGNO(01635)
                        "Authorization of user %s to access %s failed, reason: %s",
                        r->user, r->uri, reason ? reason : "unknown");
          return AUTHZ_DENIED;
      }
  
      status = apr_uid_name_get(&owner, finfo.user, r->pool);
      if (status != APR_SUCCESS || !owner) {
          reason = "could not get name of file owner";
          ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, APLOGNO(01636)
                        "Authorization of user %s to access %s failed, reason: %s",
                        r->user, r->uri, reason ? reason : "unknown");
          return AUTHZ_DENIED;
      }
  
      if (strcmp(owner, r->user)) {
          reason = apr_psprintf(r->pool, "file owner %s does not match.",
                                  owner);
          ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, APLOGNO(01637)
                        "Authorization of user %s to access %s failed, reason: %s",
                        r->user, r->uri, reason ? reason : "unknown");
          return AUTHZ_DENIED;
      }
  
      /* this user is authorized */
      return AUTHZ_GRANTED;
  #endif /* APR_HAS_USER */
  }
  
  static char *authz_owner_get_file_group(request_rec *r)
  {
      /* file-group only figures out the file's group and lets
      * other modules do the actual authorization (against a group file/db).
      * Thus, these modules have to hook themselves after
      * mod_authz_owner and of course recognize 'file-group', too.
      */
  #if !APR_HAS_USER
      return NULL;
  #else  /* APR_HAS_USER */
      char *reason = NULL;
      char *group = NULL;
      apr_finfo_t finfo;
      apr_status_t status = 0;
  
      if (!r->filename) {
          reason = "no filename available";
          ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, APLOGNO(01638)
                        "Authorization of user %s to access %s failed, reason: %s",
                        r->user, r->uri, reason ? reason : "unknown");
          return NULL;
      }
  
      status = apr_stat(&finfo, r->filename, APR_FINFO_GROUP, r->pool);
      if (status != APR_SUCCESS) {
          reason = apr_pstrcat(r->pool, "could not stat file ",
                                  r->filename, NULL);
          ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, APLOGNO(01639)
                        "Authorization of user %s to access %s failed, reason: %s",
                        r->user, r->uri, reason ? reason : "unknown");
          return NULL;
      }
  
      if (!(finfo.valid & APR_FINFO_GROUP)) {
          reason = "no file group information available";
          ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, APLOGNO(01640)
                        "Authorization of user %s to access %s failed, reason: %s",
                        r->user, r->uri, reason ? reason : "unknown");
          return NULL;
      }
  
      status = apr_gid_name_get(&group, finfo.group, r->pool);
      if (status != APR_SUCCESS || !group) {
          reason = "could not get name of file group";
          ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, APLOGNO(01641)
                        "Authorization of user %s to access %s failed, reason: %s",
                        r->user, r->uri, reason ? reason : "unknown");
          return NULL;
      }
  
      return group;
  #endif /* APR_HAS_USER */
  }
  
  static const authz_provider authz_fileowner_provider =
  {
      &fileowner_check_authorization,
      NULL,
  };
  
  static void register_hooks(apr_pool_t *p)
  {
      APR_REGISTER_OPTIONAL_FN(authz_owner_get_file_group);
  
      ap_register_auth_provider(p, AUTHZ_PROVIDER_GROUP, "file-owner",
                                AUTHZ_PROVIDER_VERSION,
                                &authz_fileowner_provider,
                                AP_AUTH_INTERNAL_PER_CONF);
  }
  
  AP_DECLARE_MODULE(authz_owner) =
  {
      STANDARD20_MODULE_STUFF,
      NULL,                          /* dir config creater */
      NULL,                          /* dir merger --- default is to override */
      NULL,                          /* server config */
      NULL,                          /* merge server config */
      authz_owner_cmds,              /* command apr_table_t */
      register_hooks                 /* register hooks */
  };
  