/* Copyright (C) 2011-2021 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 Eric Leblond <eric@regit.org>

 *

 * Implements the mark keyword. Based  on detect-gid

 * by Breno Silva <breno.silva@gmail.com>

 */

#include "suricata-common.h"

#include "suricata.h"

#include "decode.h"

#include "detect.h"

#include "flow-var.h"

#include "decode-events.h"

#include "detect-mark.h"

#include "detect-parse.h"

#include "util-unittest.h"

#include "util-byte.h"

#include "util-debug.h"

#define PARSE_REGEX "([0x]*[0-9a-f]+)/([0x]*[0-9a-f]+)"

static DetectParseRegex parse_regex;

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

static int DetectMarkPacket(DetectEngineThreadCtx *det_ctx, Packet *p,

        const Signature *s, const SigMatchCtx *ctx);

void DetectMarkDataFree(DetectEngineCtx *, void *ptr);

#if defined UNITTESTS && defined NFQ

static void MarkRegisterTests(void);

#endif

/**

 * \brief Registration function for nfq_set_mark: keyword

 */

void DetectMarkRegister (void)

{

    sigmatch_table[DETECT_MARK].name = "nfq_set_mark";

    sigmatch_table[DETECT_MARK].Match = DetectMarkPacket;

    sigmatch_table[DETECT_MARK].Setup = DetectMarkSetup;

    sigmatch_table[DETECT_MARK].Free  = DetectMarkDataFree;

#if defined UNITTESTS && defined NFQ

    sigmatch_table[DETECT_MARK].RegisterTests = MarkRegisterTests;

#endif

    DetectSetupParseRegexes(PARSE_REGEX, &parse_regex);

}

#ifdef NFQ

/**

 * \internal

 * \brief This function is used to parse mark options passed via mark: keyword

 *

 * \param rawstr Pointer to the user provided mark options

 *

 * \retval 0 on success

 * \retval < 0 on failure

 */

static void * DetectMarkParse (const char *rawstr)

{

    int res = 0;

    size_t pcre2_len;

    const char *str_ptr = NULL;

    char *ptr = NULL;

    uint32_t mark;

    uint32_t mask;

    DetectMarkData *data;

    pcre2_match_data *match = NULL;

    int ret = DetectParsePcreExec(&parse_regex, &match, rawstr, 0, 0);

    if (ret < 1) {

        SCLogError("pcre_exec parse error, ret %" PRId32 ", string %s", ret, rawstr);

        pcre2_match_data_free(match);

        return NULL;

    }

    res = pcre2_substring_get_bynumber(match, 1, (PCRE2_UCHAR8 **)&str_ptr, &pcre2_len);

    if (res < 0) {

        SCLogError("pcre2_substring_get_bynumber failed");

        goto error;

    }

    ptr = (char *)str_ptr;

    if (ptr == NULL)

        goto error;

    if (ByteExtractStringUint32(&mark, 0, strlen(ptr), ptr) <= 0) {

        SCLogError("invalid input as arg to nfq_set_mark keyword");

        pcre2_substring_free((PCRE2_UCHAR8 *)ptr);

        goto error;

    }

    res = pcre2_substring_get_bynumber(match, 2, (PCRE2_UCHAR8 **)&str_ptr, &pcre2_len);

    if (res < 0) {

        SCLogError("pcre2_substring_get_bynumber failed");

        goto error;

    }

    pcre2_substring_free((PCRE2_UCHAR8 *)ptr);

    ptr = (char *)str_ptr;

    if (ptr == NULL) {

        data = SCMalloc(sizeof(DetectMarkData));

        if (unlikely(data == NULL)) {

            goto error;

        }

        data->mark = mark;

        data->mask = 0xffff;

        pcre2_match_data_free(match);

        return data;

    }

    if (ByteExtractStringUint32(&mask, 0, strlen(ptr), ptr) <= 0) {

        SCLogError("invalid input as arg to nfq_set_mark keyword");

        pcre2_substring_free((PCRE2_UCHAR8 *)ptr);

        goto error;

    }

    SCLogDebug("Rule will set mark 0x%x with mask 0x%x", mark, mask);

    pcre2_substring_free((PCRE2_UCHAR8 *)ptr);

    data = SCMalloc(sizeof(DetectMarkData));

    if (unlikely(data == NULL)) {

        goto error;

    }

    data->mark = mark;

    data->mask = mask;

    pcre2_match_data_free(match);

    return data;

error:

    if (match) {

        pcre2_match_data_free(match);

    }

    return NULL;

}

#endif /* NFQ */

/**

 * \internal

 * \brief this function is used to add the parsed mark into the current signature

 *

 * \param de_ctx pointer to the Detection Engine Context

 * \param s pointer to the Current Signature

 * \param rawstr pointer to the user provided mark options

 *

 * \retval 0 on Success

 * \retval -1 on Failure

 */

static int DetectMarkSetup (DetectEngineCtx *de_ctx, Signature *s, const char *rawstr)

{

#ifndef NFQ

    return 0;

#else

    DetectMarkData *data = DetectMarkParse(rawstr);

    if (data == NULL) {

        return -1;

    }

    /* Append it to the list of post match, so the mark is set if the

     * full signature matches. */

    if (SCSigMatchAppendSMToList(

                de_ctx, s, DETECT_MARK, (SigMatchCtx *)data, DETECT_SM_LIST_POSTMATCH) == NULL) {

        DetectMarkDataFree(de_ctx, data);

        return -1;

    }

    return 0;

#endif

}

void DetectMarkDataFree(DetectEngineCtx *de_ctx, void *ptr)

{

    DetectMarkData *data = (DetectMarkData *)ptr;

    SCFree(data);

}

static int DetectMarkPacket(DetectEngineThreadCtx *det_ctx, Packet *p,

        const Signature *s, const SigMatchCtx *ctx)

{

#ifdef NFQ

    const DetectMarkData *nf_data = (const DetectMarkData *)ctx;

    if (nf_data->mask) {

        if (PacketIsNotTunnel(p)) {

            /* for a non-tunnel packet we don't need a lock,

             * and if we're here we can't turn into a tunnel

             * packet anymore. */

            /* coverity[missing_lock] */

            p->nfq_v.mark = (nf_data->mark & nf_data->mask)

                | (p->nfq_v.mark & ~(nf_data->mask));

            /* coverity[missing_lock] */

            p->nfq_v.mark_modified = true;

        } else {

            /* real tunnels may have multiple flows inside them, so marking

             * might 'mark' too much. Rebuilt packets from IP fragments

             * are fine. */

            if (p->flags & PKT_REBUILT_FRAGMENT) {

                Packet *tp = p->root ? p->root : p;

                SCSpinLock(&tp->persistent.tunnel_lock);

                tp->nfq_v.mark = (nf_data->mark & nf_data->mask)

                    | (tp->nfq_v.mark & ~(nf_data->mask));

                tp->nfq_v.mark_modified = true;

                SCSpinUnlock(&tp->persistent.tunnel_lock);

            }

        }

    }

#endif

    return 1;

}

/*

 * ONLY TESTS BELOW THIS COMMENT

 */

#if defined UNITTESTS && defined NFQ

/**

 * \test MarkTestParse01 is a test for a valid mark value

 *

 */

static int MarkTestParse01 (void)

{

    DetectMarkData *data;

    data = DetectMarkParse("1/1");

    FAIL_IF_NULL(data);

    FAIL_IF(data->mark != 1);

    FAIL_IF(data->mask != 1);

    DetectMarkDataFree(NULL, data);

    PASS;

}

/**

 * \test MarkTestParse02 is a test for an invalid mark value

 *

 */

static int MarkTestParse02 (void)

{

    DetectMarkData *data;

    data = DetectMarkParse("4");

    FAIL_IF_NOT_NULL(data);

    DetectMarkDataFree(NULL, data);

    PASS;

}

/**

 * \test MarkTestParse03 is a test for a valid mark value

 *

 */

static int MarkTestParse03 (void)

{

    DetectMarkData *data;

    data = DetectMarkParse("0x10/0xff");

    FAIL_IF(data->mark != 0x10);

    FAIL_IF(data->mask != 0xff);

    FAIL_IF_NULL(data);

    DetectMarkDataFree(NULL, data);

    PASS;

}

/**

 * \test MarkTestParse04 is a test for a invalid mark value

 *

 */

static int MarkTestParse04 (void)

{

    DetectMarkData *data;

    data = DetectMarkParse("0x1g/0xff");

    FAIL_IF_NOT_NULL(data);

    DetectMarkDataFree(NULL, data);

    PASS;

}

/**

 * \brief this function registers unit tests for Mark

 */

static void MarkRegisterTests(void)

{

    UtRegisterTest("MarkTestParse01", MarkTestParse01);

    UtRegisterTest("MarkTestParse02", MarkTestParse02);

    UtRegisterTest("MarkTestParse03", MarkTestParse03);

    UtRegisterTest("MarkTestParse04", MarkTestParse04);

}

#endif /* UNITTESTS */