detect-krb5-ticket-encryption.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-krb5-ticket-encryption.h"
 
#include "detect-engine.h"
#include "detect-parse.h"
 
static int g_krb5_ticket_encryption_list_id = 0;
 
static void DetectKrb5TicketEncryptionFree(DetectEngineCtx *de_ctx, void *ptr)
{
    rs_krb5_detect_encryption_free(ptr);
}
 
static int DetectKrb5TicketEncryptionMatch(DetectEngineThreadCtx *det_ctx, Flow *f, uint8_t flags,
        void *state, void *txv, const Signature *s, const SigMatchCtx *ctx)
{
    const DetectKrb5TicketEncryptionData *dd = (const DetectKrb5TicketEncryptionData *)ctx;
 
    SCEnter();
 
    SCReturnInt(rs_krb5_detect_encryption_match(txv, dd));
}
 
static int DetectKrb5TicketEncryptionSetup(
        DetectEngineCtx *de_ctx, Signature *s, const char *krb5str)
{
    DetectKrb5TicketEncryptionData *krb5d = NULL;
    SigMatch *sm = NULL;
 
    if (DetectSignatureSetAppProto(s, ALPROTO_KRB5) != 0)
        return -1;
 
    krb5d = rs_krb5_detect_encryption_parse(krb5str);
    if (krb5d == NULL)
        goto error;
 
    sm = SigMatchAlloc();
    if (sm == NULL)
        goto error;
 
    sm->type = DETECT_AL_KRB5_TICKET_ENCRYPTION;
    sm->ctx = (void *)krb5d;
 
    SigMatchAppendSMToList(s, sm, g_krb5_ticket_encryption_list_id);
 
    return 0;
 
error:
    if (krb5d != NULL)
        DetectKrb5TicketEncryptionFree(de_ctx, krb5d);
    if (sm != NULL)
        SCFree(sm);
    return -1;
}
 
void DetectKrb5TicketEncryptionRegister(void)
{
    sigmatch_table[DETECT_AL_KRB5_TICKET_ENCRYPTION].name = "krb5.ticket_encryption";
    sigmatch_table[DETECT_AL_KRB5_TICKET_ENCRYPTION].desc = "match Kerberos 5 ticket encryption";
    sigmatch_table[DETECT_AL_KRB5_TICKET_ENCRYPTION].url =
            "/rules/kerberos-keywords.html#krb5-ticket-encryption";
    sigmatch_table[DETECT_AL_KRB5_TICKET_ENCRYPTION].Match = NULL;
    sigmatch_table[DETECT_AL_KRB5_TICKET_ENCRYPTION].AppLayerTxMatch =
            DetectKrb5TicketEncryptionMatch;
    sigmatch_table[DETECT_AL_KRB5_TICKET_ENCRYPTION].Setup = DetectKrb5TicketEncryptionSetup;
    sigmatch_table[DETECT_AL_KRB5_TICKET_ENCRYPTION].Free = DetectKrb5TicketEncryptionFree;
 
    // Tickets are only from server to client
    DetectAppLayerInspectEngineRegister2("krb5_ticket_encryption", ALPROTO_KRB5, SIG_FLAG_TOCLIENT,
            0, DetectEngineInspectGenericList, NULL);
 
    g_krb5_ticket_encryption_list_id = DetectBufferTypeRegister("krb5_ticket_encryption");
    SCLogDebug("g_krb5_ticket_encryption_list_id %d", g_krb5_ticket_encryption_list_id);
}