/* Copyright (C) 2007-2021 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 Victor Julien <victor@inliniac.net>

 */

#include "suricata-common.h"

#include "decode.h"

#include "detect.h"

#include "detect-engine.h"

#include "detect-parse.h"

#include "detect-engine-state.h"

#include "detect-filestore.h"

#include "detect-engine-dcepayload.h"

#include "detect-engine-file.h"

#include "stream-tcp.h"

#include "stream-tcp-private.h"

#include "stream-tcp-reassemble.h"

#include "app-layer-parser.h"

#include "app-layer-protos.h"

#include "app-layer-htp.h"

#include "app-layer-smtp.h"

#include "util-unittest.h"

#include "util-unittest-helper.h"

#include "util-profiling.h"

#include "util-validate.h"

/**

 *  \brief Inspect the file inspecting keywords.

 *

 *  \param tv thread vars

 *  \param det_ctx detection engine thread ctx

 *  \param f flow

 *  \param s signature to inspect

 *

 *  \retval 0 no match

 *  \retval 1 match

 *  \retval 2 can't match

 *  \retval 3 can't match filestore signature

 */

static uint8_t DetectFileInspect(DetectEngineThreadCtx *det_ctx, Flow *f, const Signature *s,

        const SigMatchData *smd, uint8_t flags, FileContainer *ffc)

{

    uint8_t r = 0;

    int match = 0;

    int store_r = 0;

    SCLogDebug("file inspection... %p", ffc);

    for (File *file = ffc->head; file != NULL; file = file->next) {

        SCLogDebug("file");

        if (file->state == FILE_STATE_NONE) {

            SCLogDebug("file state FILE_STATE_NONE");

            continue;

        }

        if ((s->file_flags & FILE_SIG_NEED_FILENAME) && file->name == NULL) {

            SCLogDebug("sig needs filename, but we don't have any");

            r = DETECT_ENGINE_INSPECT_SIG_NO_MATCH;

            continue;

        }

        uint64_t file_size = FileDataSize(file);

        if ((s->file_flags & FILE_SIG_NEED_MAGIC) && file_size == 0) {

            SCLogDebug("sig needs file content, but we don't have any");

            r = DETECT_ENGINE_INSPECT_SIG_NO_MATCH;

            continue;

        }

        if ((s->file_flags & FILE_SIG_NEED_FILECONTENT) && file_size == 0) {

            SCLogDebug("sig needs file content, but we don't have any");

            r = DETECT_ENGINE_INSPECT_SIG_NO_MATCH;

            continue;

        }

        if ((s->file_flags & FILE_SIG_NEED_MD5) && (!(file->flags & FILE_MD5))) {

            SCLogDebug("sig needs file md5, but we don't have any");

            r = DETECT_ENGINE_INSPECT_SIG_NO_MATCH;

            continue;

        }

        if ((s->file_flags & FILE_SIG_NEED_SHA1) && (!(file->flags & FILE_SHA1))) {

            SCLogDebug("sig needs file sha1, but we don't have any");

            r = DETECT_ENGINE_INSPECT_SIG_NO_MATCH;

            continue;

        }

        if ((s->file_flags & FILE_SIG_NEED_SHA256) && (!(file->flags & FILE_SHA256))) {

            SCLogDebug("sig needs file sha256, but we don't have any");

            r = DETECT_ENGINE_INSPECT_SIG_NO_MATCH;

            continue;

        }

        if ((s->file_flags & FILE_SIG_NEED_SIZE) && file->state < FILE_STATE_CLOSED) {

            SCLogDebug("sig needs filesize, but state < FILE_STATE_CLOSED");

            r = DETECT_ENGINE_INSPECT_SIG_NO_MATCH;

            continue;

        }

        /* run the file match functions. */

        while (1) {

            SCLogDebug("smd %p", smd);

            if (sigmatch_table[smd->type].FileMatch != NULL) {

                KEYWORD_PROFILING_START;

                match = sigmatch_table[smd->type].FileMatch(det_ctx, f, flags, file, s, smd->ctx);

                KEYWORD_PROFILING_END(det_ctx, smd->type, (match > 0));

                if (match == 0) {

                    r = DETECT_ENGINE_INSPECT_SIG_CANT_MATCH_FILES;

                    break;

                } else if (smd->is_last) {

                    r = DETECT_ENGINE_INSPECT_SIG_MATCH;

                    break;

                }

            }

            if (smd->is_last)

                break;

            smd++;

        }

        /* continue inspection for other files as we may want to store

         * those as well. We'll return 1 (match) regardless of their

         * results though */

        if (r == DETECT_ENGINE_INSPECT_SIG_MATCH)

            store_r = DETECT_ENGINE_INSPECT_SIG_MATCH;

        /* continue, this file may (or may not) be unable to match

         * maybe we have more that can :) */

    }

    if (r == DETECT_ENGINE_INSPECT_SIG_NO_MATCH && store_r == DETECT_ENGINE_INSPECT_SIG_MATCH) {

        SCLogDebug("stored MATCH, current file NOMATCH");

        SCReturnInt(DETECT_ENGINE_INSPECT_SIG_MATCH_MORE_FILES);

    }

    if (store_r == DETECT_ENGINE_INSPECT_SIG_MATCH)

        r = DETECT_ENGINE_INSPECT_SIG_MATCH;

    SCReturnInt(r);

}

/**

 *  \brief Inspect the file inspecting keywords against the state

 *

 *  \param det_ctx detection engine thread ctx

 *  \param f flow

 *  \param s signature to inspect

 *  \param alstate state

 *  \param flags direction flag

 *

 *  \retval 0 no match

 *  \retval 1 match

 *  \retval 2 can't match

 *  \retval 3 can't match filestore signature

 *

 *  \note flow is not locked at this time

 */

uint8_t DetectFileInspectGeneric(DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx,

        const struct DetectEngineAppInspectionEngine_ *engine, const Signature *s, Flow *f,

        uint8_t flags, void *alstate, void *tx, uint64_t tx_id)

{

    SCEnter();

    DEBUG_VALIDATE_BUG_ON(f->alstate != alstate);

    const uint8_t direction = flags & (STREAM_TOSERVER|STREAM_TOCLIENT);

    AppLayerGetFileState files = AppLayerParserGetTxFiles(f, alstate, tx, direction);

    FileContainer *ffc = files.fc;

    SCLogDebug("tx %p tx_id %" PRIu64 " ffc %p ffc->head %p sid %u", tx, tx_id, ffc,

            ffc ? ffc->head : NULL, s->id);

    if (ffc == NULL) {

        SCReturnInt(DETECT_ENGINE_INSPECT_SIG_CANT_MATCH_FILES);

    } else if (ffc->head == NULL) {

        SCReturnInt(DETECT_ENGINE_INSPECT_SIG_NO_MATCH);

    }

    uint8_t r = DETECT_ENGINE_INSPECT_SIG_NO_MATCH;

    uint8_t match = DetectFileInspect(det_ctx, f, s, engine->smd, flags, ffc);

    if (match == DETECT_ENGINE_INSPECT_SIG_MATCH) {

        r = DETECT_ENGINE_INSPECT_SIG_MATCH;

    } else if (match == DETECT_ENGINE_INSPECT_SIG_CANT_MATCH) {

        SCLogDebug("sid %u can't match on this transaction", s->id);

        r = DETECT_ENGINE_INSPECT_SIG_CANT_MATCH;

    } else if (match == DETECT_ENGINE_INSPECT_SIG_CANT_MATCH_FILES) {

        SCLogDebug("sid %u can't match on this transaction (file sig)", s->id);

        r = DETECT_ENGINE_INSPECT_SIG_CANT_MATCH_FILES;

    } else if (match == DETECT_ENGINE_INSPECT_SIG_MATCH_MORE_FILES) {

        SCLogDebug("match with more files ahead");

        r = match;

    }

    SCReturnInt(r);

}