modules/aaa/mod_authz_default.c

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 *
 * Portions of this software are based upon public domain software
 * originally written at the National Center for Supercomputing Applications,
 * University of Illinois, Urbana-Champaign.
 */

/*
 * http_auth: authentication
 * 
 * Rob McCool
 * 
 * Adapted to Apache by rst.
 *
 * dirkx - Added Authoritative control to allow passing on to lower
 *         modules if and only if the userid is not known to this
 *         module. A known user with a faulty or absent password still
 *         causes an AuthRequired. The default is 'Authoritative', i.e.
 *         no control is passed along.
 */

#include "apr_strings.h"
#include "apr_md5.h"            /* for apr_password_validate */

#include "ap_config.h"
#include "httpd.h"
#include "http_config.h"
#include "http_core.h"
#include "http_log.h"
#include "http_protocol.h"
#include "http_request.h"

typedef struct {
    int authoritative;
} authz_default_config_rec;

static void *create_authz_default_dir_config(apr_pool_t *p, char *d)
{
    authz_default_config_rec *conf = apr_palloc(p, sizeof(*conf));

    conf->authoritative = 1; /* keep the fortress secure by default */
    return conf;
}

static const command_rec authz_default_cmds[] =
{
    AP_INIT_FLAG("AccessAuthoritative", ap_set_flag_slot,
                 (void *)APR_OFFSETOF(authz_default_config_rec, authoritative),
                 OR_AUTHCFG,
                 "Set to 'no' to allow access control to be passed along to "
                 "lower modules. (default is yes.)"),
    {NULL}
};

module AP_MODULE_DECLARE_DATA authz_default_module;

static int check_user_access(request_rec *r)
{
    authz_default_config_rec *conf = ap_get_module_config(r->per_dir_config,
                                                 &authz_default_module);
    int m = r->method_number;
    int method_restricted = 0;
    register int x;
    const apr_array_header_t *reqs_arr = ap_requires(r);
    require_line *reqs;

    /* BUG FIX: tadc, 11-Nov-1995.  If there is no "requires" directive, 
     * then any user will do.
     */
    if (!reqs_arr) {
        return OK;
    }
    reqs = (require_line *)reqs_arr->elts;

    for (x = 0; x < reqs_arr->nelts; x++) {
        if (!(reqs[x].method_mask & (AP_METHOD_BIT << m))) {
            continue;
        }
        method_restricted = 1;
        break;
    }

    if (method_restricted == 0) {
        return OK;
    }

    if (!(conf->authoritative)) {
        return DECLINED;
    }

    /* if we aren't authoritative, any require directive could be
     * considered valid even if noone groked it.  However, if we are 
     * authoritative, we can warn the user they did something wrong.
     *
     * That something could be a missing "AuthAuthoritative off", but
     * more likely is a typo in the require directive.
     */
    ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
                          "access to %s failed, reason: require directives "
                          "present and no Authoritative handler.", r->uri);

    ap_note_basic_auth_failure(r);
    return HTTP_UNAUTHORIZED;
}

static void register_hooks(apr_pool_t *p)
{
    ap_hook_auth_checker(check_user_access,NULL,NULL,APR_HOOK_LAST);
}

module AP_MODULE_DECLARE_DATA authz_default_module =
{
    STANDARD20_MODULE_STUFF,
    create_authz_default_dir_config, /* dir config creater */
    NULL,                            /* dir merger --- default is to override */
    NULL,                            /* server config */
    NULL,                            /* merge server config */
    authz_default_cmds,              /* command apr_table_t */
    register_hooks                   /* register hooks */
};