/* Copyright (C) 2017-2021 Open Information Security Foundation

 *

 * You can copy, redistribute or modify this Program under the terms of

 * the GNU General Public License version 2 as published by the Free

 * Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * version 2 along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA.

 */

/**

 * \file

 *

 * \author Jeff Lucovsky <jeff@lucovsky.org>

 *

 * Implement JSON/eve logging app-layer FTP.

 */

#include "suricata-common.h"

#include "detect.h"

#include "pkt-var.h"

#include "conf.h"

#include "threads.h"

#include "threadvars.h"

#include "tm-threads.h"

#include "util-unittest.h"

#include "util-buffer.h"

#include "util-debug.h"

#include "util-mem.h"

#include "output.h"

#include "output-json.h"

#include "app-layer.h"

#include "app-layer-parser.h"

#include "app-layer-ftp.h"

#include "output-json-ftp.h"

static void EveFTPLogCommand(FTPTransaction *tx, JsonBuilder *jb)

{

    /* Preallocate array objects to simplify failure case */

    JsonBuilder *js_resplist = NULL;

    if (!TAILQ_EMPTY(&tx->response_list)) {

        js_resplist = jb_new_array();

        if (unlikely(js_resplist == NULL)) {

            return;

        }

    }

    jb_set_string(jb, "command", tx->command_descriptor->command_name);

    uint32_t min_length = tx->command_descriptor->command_length + 1; /* command + space */

    if (tx->request_length > min_length) {

        jb_set_string_from_bytes(jb,

                "command_data",

                (const uint8_t *)tx->request + min_length,

                tx->request_length - min_length - 1);

        if (tx->request_truncated) {

            JB_SET_TRUE(jb, "command_truncated");

        } else {

            JB_SET_FALSE(jb, "command_truncated");

        }

    }

    bool reply_truncated = false;

    if (!TAILQ_EMPTY(&tx->response_list)) {

        int resp_cnt = 0;

        FTPString *response;

        bool is_cc_array_open = false;

        TAILQ_FOREACH(response, &tx->response_list, next) {

            /* handle multiple lines within the response, \r\n delimited */

            uint8_t *where = response->str;

            uint16_t length = 0;

            uint16_t pos;

            if (response->len > 0 && response->len <= UINT16_MAX) {

                length = (uint16_t)response->len - 1;

            } else if (response->len > UINT16_MAX) {

                length = UINT16_MAX;

            }

            if (!reply_truncated && response->truncated) {

                reply_truncated = true;

            }

            while ((pos = JsonGetNextLineFromBuffer((const char *)where, length)) != UINT16_MAX) {

                uint16_t offset = 0;

                /* Try to find a completion code for this line */

                if (pos >= 3)  {

                    /* Gather the completion code if present */

                    if (isdigit(where[0]) && isdigit(where[1]) && isdigit(where[2])) {

                        if (!is_cc_array_open) {

                            jb_open_array(jb, "completion_code");

                            is_cc_array_open = true;

                        }

                        jb_append_string_from_bytes(jb, (const uint8_t *)where, 3);

                        offset = 4;

                    }

                }

                /* move past 3 character completion code */

                if (pos >= offset) {

                    jb_append_string_from_bytes(js_resplist, (const uint8_t *)where + offset, pos - offset);

                    resp_cnt++;

                }

                where += pos;

                length -= pos;

            }

        }

        if (is_cc_array_open) {

            jb_close(jb);

        }

        if (resp_cnt) {

            jb_close(js_resplist);

            jb_set_object(jb, "reply", js_resplist);

        }

        jb_free(js_resplist);

    }

    if (tx->dyn_port) {

        jb_set_uint(jb, "dynamic_port", tx->dyn_port);

    }

    if (tx->command_descriptor->command == FTP_COMMAND_PORT ||

        tx->command_descriptor->command == FTP_COMMAND_EPRT) {

        if (tx->active) {

            JB_SET_STRING(jb, "mode", "active");

        } else {

            JB_SET_STRING(jb, "mode", "passive");

        }

    }

    if (tx->done) {

        JB_SET_STRING(jb, "reply_received", "yes");

    } else {

        JB_SET_STRING(jb, "reply_received", "no");

    }

    if (reply_truncated) {

        JB_SET_TRUE(jb, "reply_truncated");

    } else {

        JB_SET_FALSE(jb, "reply_truncated");

    }

}

static int JsonFTPLogger(ThreadVars *tv, void *thread_data,

    const Packet *p, Flow *f, void *state, void *vtx, uint64_t tx_id)

{

    SCEnter();

    OutputJsonThreadCtx *thread = thread_data;

    const char *event_type;

    if (f->alproto == ALPROTO_FTPDATA) {

        event_type = "ftp_data";

    } else {

        event_type = "ftp";

    }

    FTPTransaction *tx = vtx;

    JsonBuilder *jb =

            CreateEveHeaderWithTxId(p, LOG_DIR_FLOW, event_type, NULL, tx_id, thread->ctx);

    if (likely(jb)) {

        jb_open_object(jb, event_type);

        if (f->alproto == ALPROTO_FTPDATA) {

            EveFTPDataAddMetadata(f, jb);

        } else {

            EveFTPLogCommand(tx, jb);

        }

        if (!jb_close(jb)) {

            goto fail;

        }

        OutputJsonBuilderBuffer(jb, thread);

        jb_free(jb);

    }

    return TM_ECODE_OK;

fail:

    jb_free(jb);

    return TM_ECODE_FAILED;

}

static OutputInitResult OutputFTPLogInitSub(ConfNode *conf,

    OutputCtx *parent_ctx)

{

    AppLayerParserRegisterLogger(IPPROTO_TCP, ALPROTO_FTP);

    AppLayerParserRegisterLogger(IPPROTO_TCP, ALPROTO_FTPDATA);

    return OutputJsonLogInitSub(conf, parent_ctx);

}

void JsonFTPLogRegister(void)

{

    /* Register as an eve sub-module. */

    OutputRegisterTxSubModule(LOGGER_JSON_TX, "eve-log", "JsonFTPLog", "eve-log.ftp",

            OutputFTPLogInitSub, ALPROTO_FTP, JsonFTPLogger, JsonLogThreadInit, JsonLogThreadDeinit,

            NULL);

    OutputRegisterTxSubModule(LOGGER_JSON_TX, "eve-log", "JsonFTPLog", "eve-log.ftp",

            OutputFTPLogInitSub, ALPROTO_FTPDATA, JsonFTPLogger, JsonLogThreadInit,

            JsonLogThreadDeinit, NULL);

    SCLogDebug("FTP JSON logger registered.");

}