/* 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.

 */

/*

 * Adapted to allow anonymous logins, just like with Anon-FTP, when

 * one gives the magic user name 'anonymous' and ones email address

 * as the password.

 *

 * Just add the following tokes to your <directory> setup:

 *

 * Anonymous                    magic-userid [magic-userid]...

 *

 * Anonymous_MustGiveEmail      [ on | off ] default = on

 * Anonymous_LogEmail           [ on | off ] default = on

 * Anonymous_VerifyEmail        [ on | off ] default = off

 * Anonymous_NoUserId           [ on | off ] default = off

 *

 * The magic user id is something like 'anonymous', it is NOT case sensitive.

 *

 * The MustGiveEmail flag can be used to force users to enter something

 * in the password field (like an email address). Default is on.

 *

 * Furthermore the 'NoUserID' flag can be set to allow completely empty

 * usernames in as well; this can be is convenient as a single return

 * in broken GUIs like W95 is often given by the user. The Default is off.

 *

 * Dirk.vanGulik@jrc.it; http://ewse.ceo.org; http://me-www.jrc.it/~dirkx

 *

 */

#include "apr_strings.h"

#define APR_WANT_STRFUNC

#include "apr_want.h"

#include "ap_provider.h"

#include "httpd.h"

#include "http_config.h"

#include "http_core.h"

#include "http_log.h"

#include "http_request.h"

#include "http_protocol.h"

#include "mod_auth.h"

typedef struct anon_auth_user {

    const char *user;

    struct anon_auth_user *next;

} anon_auth_user;

typedef struct {

    anon_auth_user *users;

    int nouserid;

    int logemail;

    int verifyemail;

    int mustemail;

    int anyuserid;

} authn_anon_config_rec;

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

{

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

    /* just to illustrate the defaults really. */

    conf->users = NULL;

    conf->nouserid = 0;

    conf->anyuserid = 0;

    conf->logemail = 1;

    conf->verifyemail = 0;

    conf->mustemail = 1;

    return conf;

}

static const char *anon_set_string_slots(cmd_parms *cmd,

                                         void *my_config, const char *arg)

{

    authn_anon_config_rec *conf = my_config;

    anon_auth_user *first;

    if (!*arg) {

        return "Anonymous string cannot be empty, use Anonymous_NoUserId";

    }

    /* squeeze in a record */

    if (!conf->anyuserid) {

        if (!strcmp(arg, "*")) {

            conf->anyuserid = 1;

        }

        else {

            first = conf->users;

            conf->users = apr_palloc(cmd->pool, sizeof(*conf->users));

            conf->users->user = arg;

            conf->users->next = first;

        }

    }

    return NULL;

}

static const command_rec authn_anon_cmds[] =

{

    AP_INIT_ITERATE("Anonymous", anon_set_string_slots, NULL, OR_AUTHCFG,

     "a space-separated list of user IDs"),

    AP_INIT_FLAG("Anonymous_MustGiveEmail", ap_set_flag_slot,

     (void *)APR_OFFSETOF(authn_anon_config_rec, mustemail),

     OR_AUTHCFG, "Limited to 'on' or 'off'"),

    AP_INIT_FLAG("Anonymous_NoUserId", ap_set_flag_slot,

     (void *)APR_OFFSETOF(authn_anon_config_rec, nouserid),

     OR_AUTHCFG, "Limited to 'on' or 'off'"),

    AP_INIT_FLAG("Anonymous_VerifyEmail", ap_set_flag_slot,

     (void *)APR_OFFSETOF(authn_anon_config_rec, verifyemail),

     OR_AUTHCFG, "Limited to 'on' or 'off'"),

    AP_INIT_FLAG("Anonymous_LogEmail", ap_set_flag_slot,

     (void *)APR_OFFSETOF(authn_anon_config_rec, logemail),

     OR_AUTHCFG, "Limited to 'on' or 'off'"),

    {NULL}

};

module AP_MODULE_DECLARE_DATA authn_anon_module;

static authn_status check_anonymous(request_rec *r, const char *user,

                                    const char *sent_pw)

{

    authn_anon_config_rec *conf = ap_get_module_config(r->per_dir_config,

                                                      &authn_anon_module);

    authn_status res = AUTH_USER_NOT_FOUND;

    /* Ignore if we are not configured */

    if (!conf->users && !conf->anyuserid) {

        return AUTH_USER_NOT_FOUND;

    }

    /* Do we allow an empty userID and/or is it the magic one

     */

    if (!*user) {

        if (conf->nouserid) {

            res = AUTH_USER_FOUND;

        }

    }

    else if (conf->anyuserid) {

        res = AUTH_USER_FOUND;

    }

    else {

        anon_auth_user *p = conf->users;

        while (p) {

            if (!strcasecmp(user, p->user)) {

                res = AUTH_USER_FOUND;

                break;

            }

            p = p->next;

        }

    }

    /* Now if the supplied user-ID was ok, grant access if:

     * (a) no passwd was sent and no password and no verification

     *     were configured.

     * (b) password was sent and no verification was configured

     * (c) verification was configured and the password (sent or not)

     *     looks like an email address

     */

    if (   (res == AUTH_USER_FOUND)

        && (!conf->mustemail || *sent_pw)

        && (   !conf->verifyemail

            || (ap_strchr_c(sent_pw, '@') && ap_strchr_c(sent_pw, '.'))))

    {

        if (conf->logemail && ap_is_initial_req(r)) {

            ap_log_rerror(APLOG_MARK, APLOG_INFO, APR_SUCCESS, r, APLOGNO(01672)

                          "Anonymous: Passwd <%s> Accepted",

                          sent_pw ? sent_pw : "\'none\'");

        }

        return AUTH_GRANTED;

    }

    return (res == AUTH_USER_NOT_FOUND ? res : AUTH_DENIED);

}

static const authn_provider authn_anon_provider =

{

    &check_anonymous,

    NULL

};

static void register_hooks(apr_pool_t *p)

{

    ap_register_auth_provider(p, AUTHN_PROVIDER_GROUP, "anon",

                              AUTHN_PROVIDER_VERSION,

                              &authn_anon_provider, AP_AUTH_INTERNAL_PER_CONF);

}

AP_DECLARE_MODULE(authn_anon) =

{

    STANDARD20_MODULE_STUFF,

    create_authn_anon_dir_config, /* dir config creater */

    NULL,                         /* dir merger ensure strictness */

    NULL,                         /* server config */

    NULL,                         /* merge server config */

    authn_anon_cmds,              /* command apr_table_t */

    register_hooks                /* register hooks */

};