detect-dhcp-rebinding-time.c

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/* Copyright (C) 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.
 */
 
#include "suricata-common.h"
#include "rust.h"
#include "detect-dhcp-rebinding-time.h"
#include "detect-engine.h"
#include "detect-engine-mpm.h"
#include "detect-engine-prefilter.h"
#include "detect-engine-uint.h"
#include "detect-parse.h"
 
static int g_buffer_id = 0;
 
/**
 * \internal
 * \brief Function to match rebinding time of a TX
 *
 * \param t       Pointer to thread vars.
 * \param det_ctx Pointer to the pattern matcher thread.
 * \param f       Pointer to the current flow.
 * \param flags   Flags.
 * \param state   App layer state.
 * \param s       Pointer to the Signature.
 * \param m       Pointer to the sigmatch that we will cast into
 *                DetectU64Data.
 *
 * \retval 0 no match.
 * \retval 1 match.
 */
static int DetectDHCPRebindingTimeMatch(DetectEngineThreadCtx *det_ctx, Flow *f, uint8_t flags,
        void *state, void *txv, const Signature *s, const SigMatchCtx *ctx)
{
    SCEnter();
 
    uint64_t res;
    if (rs_dhcp_tx_get_rebinding_time(txv, &res)) {
        const DetectU64Data *dd = (const DetectU64Data *)ctx;
        if (DetectU64Match(res, dd)) {
            SCReturnInt(1);
        }
    }
    SCReturnInt(0);
}
 
/**
 * \internal
 * \brief Function to free memory associated with DetectU64Data.
 *
 * \param de_ptr Pointer to DetectU64Data.
 */
static void DetectDHCPRebindingTimeFree(DetectEngineCtx *de_ctx, void *ptr)
{
    rs_detect_u64_free(ptr);
}
 
/**
 * \brief Function to add the parsed dhcp rebinding time field 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 flags options.
 * \param type   Defines if this is notBefore or notAfter.
 *
 * \retval 0 on Success.
 * \retval -1 on Failure.
 */
static int DetectDHCPRebindingTimeSetup(DetectEngineCtx *de_ctx, Signature *s, const char *rawstr)
{
    if (DetectSignatureSetAppProto(s, ALPROTO_DHCP) != 0)
        return -1;
 
    DetectU64Data *dd = DetectU64Parse(rawstr);
    if (dd == NULL) {
        SCLogError("Parsing \'%s\' failed for %s", rawstr,
                sigmatch_table[DETECT_AL_DHCP_REBINDING_TIME].name);
        return -1;
    }
 
    /* okay so far so good, lets get this into a SigMatch
     * and put it in the Signature. */
    SigMatch *sm = SigMatchAlloc();
    if (sm == NULL)
        goto error;
 
    sm->type = DETECT_AL_DHCP_REBINDING_TIME;
    sm->ctx = (void *)dd;
 
    SigMatchAppendSMToList(s, sm, g_buffer_id);
    return 0;
 
error:
    DetectDHCPRebindingTimeFree(de_ctx, dd);
    return -1;
}
 
/**
 * \brief Registration function for dhcp.procedure keyword.
 */
void DetectDHCPRebindingTimeRegister(void)
{
    sigmatch_table[DETECT_AL_DHCP_REBINDING_TIME].name = "dhcp.rebinding_time";
    sigmatch_table[DETECT_AL_DHCP_REBINDING_TIME].desc = "match DHCP rebinding time";
    sigmatch_table[DETECT_AL_DHCP_REBINDING_TIME].url =
            "/rules/dhcp-keywords.html#dhcp-rebinding-time";
    sigmatch_table[DETECT_AL_DHCP_REBINDING_TIME].AppLayerTxMatch = DetectDHCPRebindingTimeMatch;
    sigmatch_table[DETECT_AL_DHCP_REBINDING_TIME].Setup = DetectDHCPRebindingTimeSetup;
    sigmatch_table[DETECT_AL_DHCP_REBINDING_TIME].Free = DetectDHCPRebindingTimeFree;
 
    DetectAppLayerInspectEngineRegister2("dhcp.rebinding-time", ALPROTO_DHCP, SIG_FLAG_TOSERVER, 0,
            DetectEngineInspectGenericList, NULL);
 
    DetectAppLayerInspectEngineRegister2("dhcp.rebinding-time", ALPROTO_DHCP, SIG_FLAG_TOCLIENT, 0,
            DetectEngineInspectGenericList, NULL);
 
    g_buffer_id = DetectBufferTypeGetByName("dhcp.rebinding-time");
}