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/* Copyright (C) 2020-2021 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.
*/
/**
* \ingroup decode
*
* @{
*/
/**
* \file
*
* Decode Encapsulating Security Payload (ESP)
*/
#include "suricata-common.h"
#include "decode-esp.h"
#include "flow.h"
#include "util-validate.h"
static int DecodeESPPacket(ThreadVars *tv, Packet *p, const uint8_t *pkt, uint16_t len)
{
DEBUG_VALIDATE_BUG_ON(pkt == NULL);
if (unlikely(len < ESP_HEADER_LEN)) {
ENGINE_SET_INVALID_EVENT(p, ESP_PKT_TOO_SMALL);
return -1;
}
p->esph = (ESPHdr *)pkt;
p->payload = (uint8_t *)pkt + sizeof(ESPHdr);
p->payload_len = len - sizeof(ESPHdr);
p->proto = IPPROTO_ESP;
return 0;
}
/**
* \brief Function to decode IPSEC-ESP packets
* \param tv thread vars
* \param dtv decoder thread vars
* \param p packet
* \param pkt raw packet data
* \param len length in bytes of pkt array
* \retval TM_ECODE_OK or TM_ECODE_FAILED on serious error
*/
int DecodeESP(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, const uint8_t *pkt, uint16_t len)
{
DEBUG_VALIDATE_BUG_ON(pkt == NULL);
StatsIncr(tv, dtv->counter_esp);
if (!PacketIncreaseCheckLayers(p)) {
return TM_ECODE_FAILED;
}
if (unlikely(DecodeESPPacket(tv, p, pkt, len) < 0)) {
CLEAR_ESP_PACKET(p);
return TM_ECODE_FAILED;
}
SCLogDebug("ESP spi: %" PRIu32 " sequence: %" PRIu32, ESP_GET_SPI(p), ESP_GET_SEQUENCE(p));
FlowSetupPacket(p);
return TM_ECODE_OK;
}
#ifdef UNITTESTS
#include "util-unittest.h"
/** \test Successful decoding */
static int DecodeESPTest01(void)
{
uint8_t raw_esp[] = { 0x00, 0x00, 0x00, 0x7b, 0x00, 0x00, 0x00, 0x08 };
Packet *p = PacketGetFromAlloc();
FAIL_IF_NULL(p);
ThreadVars tv;
DecodeThreadVars dtv;
memset(&tv, 0, sizeof(ThreadVars));
memset(&dtv, 0, sizeof(DecodeThreadVars));
int ret = DecodeESP(&tv, &dtv, p, raw_esp, sizeof(raw_esp));
FAIL_IF(ret != TM_ECODE_OK);
FAIL_IF(p->proto != IPPROTO_ESP);
FAIL_IF(p->payload_len != sizeof(raw_esp) - ESP_HEADER_LEN);
FAIL_IF(ESP_GET_SPI(p) != 0x7b);
FAIL_IF(ESP_GET_SEQUENCE(p) != 0x08);
SCFree(p);
PASS;
}
/** \test Successful decoding, with payload data */
static int DecodeESPTest02(void)
{
uint8_t raw_esp[] = { 0x00, 0x00, 0x00, 0x7b, 0x00, 0x00, 0x00, 0x08, 0xFF, 0xFF };
Packet *p = PacketGetFromAlloc();
FAIL_IF_NULL(p);
ThreadVars tv;
DecodeThreadVars dtv;
memset(&tv, 0, sizeof(ThreadVars));
memset(&dtv, 0, sizeof(DecodeThreadVars));
int ret = DecodeESP(&tv, &dtv, p, raw_esp, sizeof(raw_esp));
FAIL_IF(ret != TM_ECODE_OK);
FAIL_IF(p->proto != IPPROTO_ESP);
FAIL_IF(p->payload_len != sizeof(raw_esp) - ESP_HEADER_LEN);
FAIL_IF(memcmp(p->payload, raw_esp + ESP_HEADER_LEN, p->payload_len) != 0);
FAIL_IF(ESP_GET_SPI(p) != 0x7b);
FAIL_IF(ESP_GET_SEQUENCE(p) != 0x08);
SCFree(p);
PASS;
}
/** \test Failure decoding, not enough data */
static int DecodeESPTest03(void)
{
uint8_t raw_esp[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
Packet *p = PacketGetFromAlloc();
FAIL_IF_NULL(p);
ThreadVars tv;
DecodeThreadVars dtv;
memset(&tv, 0, sizeof(ThreadVars));
memset(&dtv, 0, sizeof(DecodeThreadVars));
int ret = DecodeESP(&tv, &dtv, p, raw_esp, sizeof(raw_esp));
FAIL_IF(ret != TM_ECODE_FAILED);
// expect ESP_PKT_TOO_SMALL
FAIL_IF_NOT(ENGINE_ISSET_EVENT(p, ESP_PKT_TOO_SMALL));
SCFree(p);
PASS;
}
/** \test Failure decoding, no data */
static int DecodeESPTest04(void)
{
uint8_t raw_esp[] = {};
Packet *p = PacketGetFromAlloc();
FAIL_IF_NULL(p);
ThreadVars tv;
DecodeThreadVars dtv;
memset(&tv, 0, sizeof(ThreadVars));
memset(&dtv, 0, sizeof(DecodeThreadVars));
int ret = DecodeESP(&tv, &dtv, p, raw_esp, sizeof(raw_esp));
FAIL_IF(ret != TM_ECODE_FAILED);
// expect ESP_PKT_TOO_SMALL
FAIL_IF_NOT(ENGINE_ISSET_EVENT(p, ESP_PKT_TOO_SMALL));
SCFree(p);
PASS;
}
#endif /* UNITTESTS */
void DecodeESPRegisterTests(void)
{
#ifdef UNITTESTS
UtRegisterTest("DecodeESPTest01", DecodeESPTest01);
UtRegisterTest("DecodeESPTest02", DecodeESPTest02);
UtRegisterTest("DecodeESPTest03", DecodeESPTest03);
UtRegisterTest("DecodeESPTest04", DecodeESPTest04);
#endif /* UNITTESTS */
}
/**
* @}
*/
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