/* 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.

 */

/* This module is triggered by an

 *

 *          AuthGroupFile standard /path/to/file

 *

 * and the presence of a

 *

 *         require group <list-of-groups>

 *

 * In an applicable limit/directory block for that method.

 *

 * If there are no AuthGroupFile directives valid for

 * the request; we DECLINED.

 *

 * If the AuthGroupFile is defined; but somehow not

 * accessible: we SERVER_ERROR (was DECLINED).

 *

 * If there are no 'require ' directives defined for

 * this request then we DECLINED (was OK).

 *

 * If there are no 'require ' directives valid for

 * this request method then we DECLINED. (was OK)

 *

 * If there are any 'require group' blocks and we

 * are not in any group - we HTTP_UNAUTHORIZE

 *

 */

#include "apr_strings.h"

#include "apr_lib.h" /* apr_isspace */

#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 "util_varbuf.h"

#include "mod_auth.h"

#include "mod_authz_owner.h"

typedef struct {

    char *groupfile;

} authz_groupfile_config_rec;

static void *create_authz_groupfile_dir_config(apr_pool_t *p, char *d)

{

    authz_groupfile_config_rec *conf = apr_palloc(p, sizeof(*conf));

    conf->groupfile = NULL;

    return conf;

}

static const command_rec authz_groupfile_cmds[] =

{

    AP_INIT_TAKE1("AuthGroupFile", ap_set_file_slot,

                  (void *)APR_OFFSETOF(authz_groupfile_config_rec, groupfile),

                  OR_AUTHCFG,

                  "text file containing group names and member user IDs"),

    {NULL}

};

module AP_MODULE_DECLARE_DATA authz_groupfile_module;

#define VARBUF_INIT_LEN 512

#define VARBUF_MAX_LEN  (16*1024*1024)

static apr_status_t groups_for_user(apr_pool_t *p, char *user, char *grpfile,

                                    apr_table_t ** out)

{

    ap_configfile_t *f;

    apr_table_t *grps = apr_table_make(p, 15);

    apr_pool_t *sp;

    struct ap_varbuf vb;

    const char *group_name, *ll, *w;

    apr_status_t status;

    apr_size_t group_len;

    if ((status = ap_pcfg_openfile(&f, p, grpfile)) != APR_SUCCESS) {

        return status ;

    }

    apr_pool_create(&sp, p);

    ap_varbuf_init(p, &vb, VARBUF_INIT_LEN);

    while (!(ap_varbuf_cfg_getline(&vb, f, VARBUF_MAX_LEN))) {

        if ((vb.buf[0] == '#') || (!vb.buf[0])) {

            continue;

        }

        ll = vb.buf;

        apr_pool_clear(sp);

        group_name = ap_getword(sp, &ll, ':');

        group_len = strlen(group_name);

        while (group_len && apr_isspace(*(group_name + group_len - 1))) {

            --group_len;

        }

        while (ll[0]) {

            w = ap_getword_conf(sp, &ll);

            if (!strcmp(w, user)) {

                apr_table_setn(grps, apr_pstrmemdup(p, group_name, group_len),

                               "in");

                break;

            }

        }

    }

    ap_cfg_closefile(f);

    apr_pool_destroy(sp);

    ap_varbuf_free(&vb;;

    *out = grps;

    return APR_SUCCESS;

}

static authz_status group_check_authorization(request_rec *r,

                                              const char *require_args,

                                              const void *parsed_require_args)

{

    authz_groupfile_config_rec *conf = ap_get_module_config(r->per_dir_config,

            &authz_groupfile_module);

    char *user = r->user;

    const char *err = NULL;

    const ap_expr_info_t *expr = parsed_require_args;

    const char *require;

    const char *t, *w;

    apr_table_t *grpstatus = NULL;

    apr_status_t status;

    if (!user) {

        return AUTHZ_DENIED_NO_USER;

    }

    /* If there is no group file - then we are not

     * configured. So decline.

     */

    if (!(conf->groupfile)) {

        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01664)

                        "No group file was specified in the configuration");

        return AUTHZ_DENIED;

    }

    status = groups_for_user(r->pool, user, conf->groupfile,

                                &grpstatus);

    if (status != APR_SUCCESS) {

        ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, APLOGNO(01665)

                        "Could not open group file: %s",

                        conf->groupfile);

        return AUTHZ_DENIED;

    }

    if (apr_is_empty_table(grpstatus)) {

        /* no groups available, so exit immediately */

        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01666)

                      "Authorization of user %s to access %s failed, reason: "

                      "user doesn't appear in group file (%s).",

                      r->user, r->uri, conf->groupfile);

        return AUTHZ_DENIED;

    }

    require = ap_expr_str_exec(r, expr, &err;;

    if (err) {

        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(02592)

                      "authz_groupfile authorize: require group: Can't "

                      "evaluate require expression: %s", err);

        return AUTHZ_DENIED;

    }

    t = require;

    while ((w = ap_getword_conf(r->pool, &t)) && w[0]) {

        if (apr_table_get(grpstatus, w)) {

            return AUTHZ_GRANTED;

        }

    }

    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01667)

                    "Authorization of user %s to access %s failed, reason: "

                    "user is not part of the 'require'ed group(s).",

                    r->user, r->uri);

    return AUTHZ_DENIED;

}

static APR_OPTIONAL_FN_TYPE(authz_owner_get_file_group) *authz_owner_get_file_group;

static authz_status filegroup_check_authorization(request_rec *r,

                                                  const char *require_args,

                                                  const void *parsed_require_args)

{

    authz_groupfile_config_rec *conf = ap_get_module_config(r->per_dir_config,

            &authz_groupfile_module);

    char *user = r->user;

    apr_table_t *grpstatus = NULL;

    apr_status_t status;

    const char *filegroup = NULL;

    if (!user) {

        return AUTHZ_DENIED_NO_USER;

    }

    /* If there is no group file - then we are not

     * configured. So decline.

     */

    if (!(conf->groupfile)) {

        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01668)

                        "No group file was specified in the configuration");

        return AUTHZ_DENIED;

    }

    status = groups_for_user(r->pool, user, conf->groupfile,

                             &grpstatus);

    if (status != APR_SUCCESS) {

        ap_log_rerror(APLOG_MARK, APLOG_ERR, status, r, APLOGNO(01669)

                      "Could not open group file: %s",

                      conf->groupfile);

        return AUTHZ_DENIED;

    }

    if (apr_is_empty_table(grpstatus)) {

        /* no groups available, so exit immediately */

        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, APLOGNO(01670)

                        "Authorization of user %s to access %s failed, reason: "

                        "user doesn't appear in group file (%s).",

                        r->user, r->uri, conf->groupfile);

        return AUTHZ_DENIED;

    }

    filegroup = authz_owner_get_file_group(r);

    if (filegroup) {

        if (apr_table_get(grpstatus, filegroup)) {

            return AUTHZ_GRANTED;

        }

    }

    else {

        /* No need to emit a error log entry because the call

        to authz_owner_get_file_group already did it

        for us.

        */

        return AUTHZ_DENIED;

    }

    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01671)

                  "Authorization of user %s to access %s failed, reason: "

                  "user is not part of the 'require'ed file group.",

                  r->user, r->uri);

    return AUTHZ_DENIED;

}

static const char *groupfile_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_group_provider =

{

    &group_check_authorization,

    &groupfile_parse_config,

};

static const authz_provider authz_filegroup_provider =

{

    &filegroup_check_authorization,

    NULL,

};

static void authz_groupfile_getfns(void)

{

    authz_owner_get_file_group = APR_RETRIEVE_OPTIONAL_FN(authz_owner_get_file_group);

}

static void register_hooks(apr_pool_t *p)

{

    ap_register_auth_provider(p, AUTHZ_PROVIDER_GROUP, "group",

                              AUTHZ_PROVIDER_VERSION,

                              &authz_group_provider,

                              AP_AUTH_INTERNAL_PER_CONF);

    ap_register_auth_provider(p, AUTHZ_PROVIDER_GROUP, "file-group",

                              AUTHZ_PROVIDER_VERSION,

                              &authz_filegroup_provider,

                              AP_AUTH_INTERNAL_PER_CONF);

    ap_hook_optional_fn_retrieve(authz_groupfile_getfns, NULL, NULL, APR_HOOK_MIDDLE);

}

AP_DECLARE_MODULE(authz_groupfile) =

{

    STANDARD20_MODULE_STUFF,

    create_authz_groupfile_dir_config,/* dir config creater */

    NULL,                             /* dir merger -- default is to override */

    NULL,                             /* server config */

    NULL,                             /* merge server config */

    authz_groupfile_cmds,             /* command apr_table_t */

    register_hooks                    /* register hooks */

};