res_security_log.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2009, Digium, Inc.
 *
 * Russell Bryant <russell@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */
 
/*!
 * \file
 *
 * \author Russell Bryant <russell@digium.com>
 *
 * \brief Security Event Logging
 *
 * \todo Make informational security events optional
 * \todo Escape quotes in string payload IE contents
 */
 
/*** MODULEINFO
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include "asterisk/module.h"
#include "asterisk/logger.h"
#include "asterisk/threadstorage.h"
#include "asterisk/strings.h"
#include "asterisk/security_events.h"
#include "asterisk/stasis.h"
#include "asterisk/json.h"
 
static const char LOG_SECURITY_NAME[] = "SECURITY";
 
static int LOG_SECURITY;
 
static struct stasis_subscription *security_stasis_sub;
 
AST_THREADSTORAGE(security_event_buf);
static const size_t SECURITY_EVENT_BUF_INIT_LEN = 256;
 
enum ie_required {
    NOT_REQUIRED,
    REQUIRED
};
 
static void append_json_single(struct ast_str **str, struct ast_json *json,
        const enum ast_event_ie_type ie_type, enum ie_required required)
{
    const char *ie_type_key = ast_event_get_ie_type_name(ie_type);
 
    struct ast_json *json_string;
 
    json_string = ast_json_object_get(json, ie_type_key);
 
    if (!required && !json_string) {
        /* Optional IE isn't present. Ignore. */
        return;
    }
 
    /* At this point, it _better_ be there! */
    ast_assert(json_string != NULL);
 
    ast_str_append(str, 0, ",%s=\"%s\"",
            ie_type_key,
            ast_json_string_get(json_string));
}
 
static void append_json(struct ast_str **str, struct ast_json *json,
        const struct ast_security_event_ie_type *ies, enum ie_required required)
{
    unsigned int i;
 
    for (i = 0; ies[i].ie_type != AST_EVENT_IE_END; i++) {
        append_json_single(str, json, ies[i].ie_type, required);
    }
}
 
static void security_event_stasis_cb(struct ast_json *json)
{
    struct ast_str *str;
    struct ast_json *event_type_json;
    enum ast_security_event_type event_type;
 
    event_type_json = ast_json_object_get(json, "SecurityEvent");
    event_type = ast_json_integer_get(event_type_json);
 
    ast_assert((unsigned int)event_type < AST_SECURITY_EVENT_NUM_TYPES);
 
    if (!(str = ast_str_thread_get(&security_event_buf,
            SECURITY_EVENT_BUF_INIT_LEN))) {
        return;
    }
 
    ast_str_set(&str, 0, "SecurityEvent=\"%s\"",
            ast_security_event_get_name(event_type));
 
    append_json(&str, json,
            ast_security_event_get_required_ies(event_type), REQUIRED);
    append_json(&str, json,
            ast_security_event_get_optional_ies(event_type), NOT_REQUIRED);
 
    ast_log_dynamic_level(LOG_SECURITY, "%s\n", ast_str_buffer(str));
}
 
static void security_stasis_cb(void *data, struct stasis_subscription *sub,
    struct stasis_message *message)
{
    struct ast_json_payload *payload = stasis_message_data(message);
 
    if (stasis_message_type(message) != ast_security_event_type()) {
        return;
    }
 
    if (!payload) {
        return;
    }
 
    security_event_stasis_cb(payload->json);
}
 
static int load_module(void)
{
    if ((LOG_SECURITY = ast_logger_register_level(LOG_SECURITY_NAME)) == -1) {
        return AST_MODULE_LOAD_DECLINE;
    }
 
    if (!(security_stasis_sub = stasis_subscribe(ast_security_topic(), security_stasis_cb, NULL))) {
        ast_logger_unregister_level(LOG_SECURITY_NAME);
        LOG_SECURITY = -1;
        return AST_MODULE_LOAD_DECLINE;
    }
    stasis_subscription_accept_message_type(security_stasis_sub, ast_security_event_type());
    stasis_subscription_set_filter(security_stasis_sub, STASIS_SUBSCRIPTION_FILTER_SELECTIVE);
 
    ast_verb(3, "Security Logging Enabled\n");
 
    return AST_MODULE_LOAD_SUCCESS;
}
 
static int unload_module(void)
{
    if (security_stasis_sub) {
        security_stasis_sub = stasis_unsubscribe_and_join(security_stasis_sub);
    }
 
    ast_logger_unregister_level(LOG_SECURITY_NAME);
 
    ast_verb(3, "Security Logging Disabled\n");
 
    return 0;
}
 
AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Security Event Logging");