/* Copyright (C) 2007-2022 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>

 * \author Pablo Rincon <pablo.rincon.crespo@gmail.com>

 *

 */

#include "suricata-common.h"

#include "threads.h"

#include "decode.h"

#include "detect.h"

#include "detect-engine.h"

#include "detect-engine-buffer.h"

#include "detect-engine-mpm.h"

#include "detect-engine-state.h"

#include "detect-engine-file.h"

#include "detect-engine-prefilter.h"

#include "detect-engine-content-inspection.h"

#include "detect-parse.h"

#include "detect-content.h"

#include "detect-file-data.h"

#include "flow.h"

#include "flow-var.h"

#include "flow-util.h"

#include "util-debug.h"

#include "util-spm-bm.h"

#include "util-unittest.h"

#include "util-unittest-helper.h"

#include "util-profiling.h"

#include "app-layer.h"

#include "app-layer-htp.h"

#include "stream-tcp.h"

#include "detect-filename.h"

#include "app-layer-parser.h"

static int DetectFileextSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str);

static int DetectFilenameSetup (DetectEngineCtx *, Signature *, const char *);

static int DetectFilenameSetupSticky(DetectEngineCtx *de_ctx, Signature *s, const char *str);

#ifdef UNITTESTS

static void DetectFilenameRegisterTests(void);

#endif

static int g_file_match_list_id = 0;

static int g_file_name_buffer_id = 0;

static int PrefilterMpmFilenameRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx,

        const DetectBufferMpmRegistry *mpm_reg, int list_id);

static uint8_t DetectEngineInspectFilename(DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx,

        const DetectEngineAppInspectionEngine *engine, const Signature *s, Flow *f, uint8_t flags,

        void *alstate, void *txv, uint64_t tx_id);

/**

 * \brief Registration function for keyword: filename

 */

void DetectFilenameRegister(void)

{

    sigmatch_table[DETECT_FILENAME].name = "filename";

    sigmatch_table[DETECT_FILENAME].desc = "match on the file name";

    sigmatch_table[DETECT_FILENAME].url = "/rules/file-keywords.html#filename";

    sigmatch_table[DETECT_FILENAME].Setup = DetectFilenameSetup;

#ifdef UNITTESTS

    sigmatch_table[DETECT_FILENAME].RegisterTests = DetectFilenameRegisterTests;

#endif

    sigmatch_table[DETECT_FILENAME].flags = SIGMATCH_QUOTES_OPTIONAL|SIGMATCH_HANDLE_NEGATION;

    sigmatch_table[DETECT_FILENAME].alternative = DETECT_FILE_NAME;

    sigmatch_table[DETECT_FILEEXT].name = "fileext";

    sigmatch_table[DETECT_FILEEXT].desc = "match on the extension of a file name";

    sigmatch_table[DETECT_FILEEXT].url = "/rules/file-keywords.html#fileext";

    sigmatch_table[DETECT_FILEEXT].Setup = DetectFileextSetup;

    sigmatch_table[DETECT_FILEEXT].flags = SIGMATCH_QUOTES_OPTIONAL | SIGMATCH_HANDLE_NEGATION;

    sigmatch_table[DETECT_FILEEXT].alternative = DETECT_FILE_NAME;

    sigmatch_table[DETECT_FILE_NAME].name = "file.name";

    sigmatch_table[DETECT_FILE_NAME].desc = "sticky buffer to match on the file name";

    sigmatch_table[DETECT_FILE_NAME].url = "/rules/file-keywords.html#filename";

    sigmatch_table[DETECT_FILE_NAME].Setup = DetectFilenameSetupSticky;

    sigmatch_table[DETECT_FILE_NAME].flags =

            SIGMATCH_OPTIONAL_OPT | SIGMATCH_INFO_STICKY_BUFFER | SIGMATCH_SUPPORT_DIR;

    DetectBufferTypeSetDescriptionByName("file.name", "file name");

    g_file_match_list_id = DetectBufferTypeRegister("files");

    g_file_name_buffer_id = DetectBufferTypeRegister("file.name");

    SCLogDebug("registering filename rule option");

    filehandler_table[DETECT_FILENAME].name = "files";

    filehandler_table[DETECT_FILENAME].priority = 0;

    filehandler_table[DETECT_FILENAME].PrefilterFn = NULL;

    filehandler_table[DETECT_FILENAME].Callback = DetectFileInspectGeneric;

    filehandler_table[DETECT_FILE_NAME].name = "file.name";

    filehandler_table[DETECT_FILE_NAME].priority = 2;

    filehandler_table[DETECT_FILE_NAME].PrefilterFn = PrefilterMpmFilenameRegister;

    filehandler_table[DETECT_FILE_NAME].Callback = DetectEngineInspectFilename;

    DetectBufferTypeSupportsMultiInstance("file.name");

}

static int DetectFileextSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)

{

    if (s->init_data->transforms.cnt) {

        SCLogError("previous transforms not consumed before 'fileext'");

        SCReturnInt(-1);

    }

    s->init_data->list = DETECT_SM_LIST_NOTSET;

    s->file_flags |= (FILE_SIG_NEED_FILE | FILE_SIG_NEED_FILENAME);

    size_t dotstr_len = strlen(str) + 2;

    char *dotstr = SCCalloc(1, dotstr_len);

    if (dotstr == NULL)

        return -1;

    dotstr[0] = '.';

    strlcat(dotstr, str, dotstr_len);

    if (DetectContentSetup(de_ctx, s, dotstr) < 0) {

        SCFree(dotstr);

        return -1;

    }

    SCFree(dotstr);

    SigMatch *sm = DetectGetLastSMFromLists(s, DETECT_CONTENT, -1);

    if (sm == NULL)

        return -1;

    DetectContentData *cd = (DetectContentData *)sm->ctx;

    cd->flags |= DETECT_CONTENT_ENDS_WITH;

    if (DetectContentConvertToNocase(de_ctx, cd) != 0)

        return -1;

    if (DetectEngineContentModifierBufferSetup(

                de_ctx, s, NULL, DETECT_FILE_NAME, g_file_name_buffer_id, s->alproto) < 0)

        return -1;

    return 0;

}

/**

 * \brief this function is used to parse filename options

 * \brief into the current signature

 *

 * \param de_ctx pointer to the Detection Engine Context

 * \param s pointer to the Current Signature

 * \param str pointer to the user provided "filename" option

 *

 * \retval 0 on Success

 * \retval -1 on Failure

 */

static int DetectFilenameSetup (DetectEngineCtx *de_ctx, Signature *s, const char *str)

{

    if (s->init_data->transforms.cnt) {

        SCLogError("previous transforms not consumed before 'filename'");

        SCReturnInt(-1);

    }

    s->init_data->list = DETECT_SM_LIST_NOTSET;

    s->file_flags |= (FILE_SIG_NEED_FILE | FILE_SIG_NEED_FILENAME);

    if (DetectContentSetup(de_ctx, s, str) < 0) {

        return -1;

    }

    SigMatch *sm = DetectGetLastSMFromLists(s, DETECT_CONTENT, -1);

    if (sm == NULL)

        return -1;

    DetectContentData *cd = (DetectContentData *)sm->ctx;

    if (DetectContentConvertToNocase(de_ctx, cd) != 0)

        return -1;

    if (DetectEngineContentModifierBufferSetup(

                de_ctx, s, NULL, DETECT_FILE_NAME, g_file_name_buffer_id, s->alproto) < 0)

        return -1;

    return 0;

}

/* file.name implementation */

/**

 * \brief this function setup the file.data keyword used in the rule

 *

 * \param de_ctx   Pointer to the Detection Engine Context

 * \param s        Pointer to the Signature to which the current keyword belongs

 * \param str      Should hold an empty string always

 *

 * \retval 0       On success

 */

static int DetectFilenameSetupSticky(DetectEngineCtx *de_ctx, Signature *s, const char *str)

{

    if (SCDetectBufferSetActiveList(de_ctx, s, g_file_name_buffer_id) < 0)

        return -1;

    s->file_flags |= (FILE_SIG_NEED_FILE | FILE_SIG_NEED_FILENAME);

    return 0;

}

static InspectionBuffer *FilenameGetDataCallback(DetectEngineThreadCtx *det_ctx,

        const DetectEngineTransforms *transforms, Flow *f, uint8_t flow_flags, File *cur_file,

        int list_id, int local_file_id)

{

    SCEnter();

    InspectionBuffer *buffer = InspectionBufferMultipleForListGet(det_ctx, list_id, local_file_id);

    if (buffer == NULL)

        return NULL;

    if (buffer->initialized)

        return buffer;

    const uint8_t *data = cur_file->name;

    uint32_t data_len = cur_file->name_len;

    InspectionBufferSetupMulti(det_ctx, buffer, transforms, data, data_len);

    SCReturnPtr(buffer, "InspectionBuffer");

}

static uint8_t DetectEngineInspectFilename(DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx,

        const DetectEngineAppInspectionEngine *engine, const Signature *s, Flow *f, uint8_t flags,

        void *alstate, void *txv, uint64_t tx_id)

{

    const DetectEngineTransforms *transforms = NULL;

    if (!engine->mpm) {

        transforms = engine->v2.transforms;

    }

    AppLayerGetFileState files = AppLayerParserGetTxFiles(f, txv, flags);

    FileContainer *ffc = files.fc;

    if (ffc == NULL || ffc->head == NULL) {

        const bool eof = (AppLayerParserGetStateProgress(f->proto, f->alproto, txv, flags) >

                          engine->progress);

        if (eof && engine->match_on_null) {

            return DETECT_ENGINE_INSPECT_SIG_MATCH;

        }

        if (ffc != NULL) {

            return DETECT_ENGINE_INSPECT_SIG_NO_MATCH;

        }

        return DETECT_ENGINE_INSPECT_SIG_CANT_MATCH_FILES;

    }

    uint8_t r = DETECT_ENGINE_INSPECT_SIG_NO_MATCH;

    int local_file_id = 0;

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

        InspectionBuffer *buffer = FilenameGetDataCallback(

                det_ctx, transforms, f, flags, file, engine->sm_list, local_file_id);

        if (buffer == NULL) {

            local_file_id++;

            continue;

        }

        const bool match = DetectEngineContentInspection(de_ctx, det_ctx, s, engine->smd, NULL, f,

                buffer->inspect, buffer->inspect_len, buffer->inspect_offset,

                DETECT_CI_FLAGS_SINGLE, DETECT_ENGINE_CONTENT_INSPECTION_MODE_STATE);

        if (match) {

            return DETECT_ENGINE_INSPECT_SIG_MATCH;

        } else {

            r = DETECT_ENGINE_INSPECT_SIG_CANT_MATCH_FILES;

        }

        local_file_id++;

    }

    return r;

}

typedef struct PrefilterMpmFilename {

    int list_id;

    const MpmCtx *mpm_ctx;

    const DetectEngineTransforms *transforms;

} PrefilterMpmFilename;

/** \brief Filedata Filedata Mpm prefilter callback

 *

 *  \param det_ctx detection engine thread ctx

 *  \param p packet to inspect

 *  \param f flow to inspect

 *  \param txv tx to inspect

 *  \param pectx inspection context

 */

static void PrefilterTxFilename(DetectEngineThreadCtx *det_ctx, const void *pectx, Packet *p,

        Flow *f, void *txv, const uint64_t idx, const AppLayerTxData *txd, const uint8_t flags)

{

    SCEnter();

    if (!AppLayerParserHasFilesInDir(txd, flags))

        return;

    const PrefilterMpmFilename *ctx = (const PrefilterMpmFilename *)pectx;

    const MpmCtx *mpm_ctx = ctx->mpm_ctx;

    const int list_id = ctx->list_id;

    AppLayerGetFileState files = AppLayerParserGetTxFiles(f, txv, flags);

    FileContainer *ffc = files.fc;

    if (ffc != NULL) {

        int local_file_id = 0;

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

            InspectionBuffer *buffer = FilenameGetDataCallback(

                    det_ctx, ctx->transforms, f, flags, file, list_id, local_file_id);

            if (buffer == NULL)

                continue;

            if (buffer->inspect_len >= mpm_ctx->minlen) {

                (void)mpm_table[mpm_ctx->mpm_type].Search(mpm_ctx, &det_ctx->mtc, &det_ctx->pmq,

                        buffer->inspect, buffer->inspect_len);

                PREFILTER_PROFILING_ADD_BYTES(det_ctx, buffer->inspect_len);

            }

            local_file_id++;

        }

    }

}

static void PrefilterMpmFilenameFree(void *ptr)

{

    SCFree(ptr);

}

static int PrefilterMpmFilenameRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx,

        const DetectBufferMpmRegistry *mpm_reg, int list_id)

{

    PrefilterMpmFilename *pectx = SCCalloc(1, sizeof(*pectx));

    if (pectx == NULL)

        return -1;

    pectx->list_id = list_id;

    pectx->mpm_ctx = mpm_ctx;

    pectx->transforms = &mpm_reg->transforms;

    return PrefilterAppendTxEngine(de_ctx, sgh, PrefilterTxFilename,

            mpm_reg->app_v2.alproto, mpm_reg->app_v2.tx_min_progress,

            pectx, PrefilterMpmFilenameFree, mpm_reg->pname);

}

#ifdef UNITTESTS /* UNITTESTS */

/**

 * \test Test parser accepting valid rules and rejecting invalid rules

 */

static int DetectFilenameSignatureParseTest01(void)

{

    FAIL_IF_NOT(UTHParseSignature("alert http any any -> any any (flow:to_client; file.name; content:\"abc\"; sid:1;)", true));

    FAIL_IF_NOT(UTHParseSignature("alert http any any -> any any (flow:to_client; file.name; content:\"abc\"; nocase; sid:1;)", true));

    FAIL_IF_NOT(UTHParseSignature("alert http any any -> any any (flow:to_client; file.name; content:\"abc\"; endswith; sid:1;)", true));

    FAIL_IF_NOT(UTHParseSignature("alert http any any -> any any (flow:to_client; file.name; content:\"abc\"; startswith; sid:1;)", true));

    FAIL_IF_NOT(UTHParseSignature("alert http any any -> any any (flow:to_client; file.name; content:\"abc\"; startswith; endswith; sid:1;)", true));

    FAIL_IF_NOT(UTHParseSignature("alert http any any -> any any (flow:to_client; file.name; bsize:10; sid:1;)", true));

    FAIL_IF_NOT(UTHParseSignature("alert http any any -> any any (flow:to_client; file.name; content:\"abc\"; rawbytes; sid:1;)", false));

    FAIL_IF_NOT(UTHParseSignature("alert tcp any any -> any any (flow:to_client; file.name; sid:1;)", false));

    //FAIL_IF_NOT(UTHParseSignature("alert tls any any -> any any (flow:to_client; file.name; content:\"abc\"; sid:1;)", false));

    PASS;

}

/**

 * \brief this function registers unit tests for DetectFilename

 */

void DetectFilenameRegisterTests(void)

{

    UtRegisterTest("DetectFilenameSignatureParseTest01", DetectFilenameSignatureParseTest01);

}

#endif /* UNITTESTS */