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suricata/src/decode-geneve.c

505 lines
18 KiB
C

/* 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.
*/
/**
* \file
*
* \author Ali Jad Khalil <jadkhal@amazon.com>
*
* Geneve tunneling scheme decoder.
*
* This implementation is based on the following specification doc:
* https://tools.ietf.org/html/draft-ietf-nvo3-geneve-16#section-3
*/
#include "suricata-common.h"
#include "decode.h"
#include "decode-geneve.h"
#include "decode-events.h"
#include "detect-engine-port.h"
#include "flow.h"
#include "util-validate.h"
#include "util-unittest.h"
#include "util-debug.h"
#include "pkt-var.h"
#include "util-profiling.h"
#include "host.h"
#define VALID_GENEVE_VERSIONS \
{ \
0 \
}
#define GENEVE_VERSION(hdr_ptr) (hdr_ptr->ver_plus_len >> 6)
#define GENEVE_RESERVED_FLAGS(hdr_ptr) (hdr_ptr->flags & 0x3F)
#define GENEVE_MIN_HEADER_LEN sizeof(GeneveHeader)
#define GENEVE_TOTAL_OPT_LEN(hdr_ptr) ((hdr_ptr->ver_plus_len & 0x3F) << 2)
#define GENEVE_TOTAL_HEADER_LEN(hdr_ptr) (GENEVE_MIN_HEADER_LEN + GENEVE_TOTAL_OPT_LEN(hdr_ptr))
#define GENEVE_MIN_SINGLE_OPT_LEN sizeof(GeneveOption)
#define GENEVE_SINGLE_OPT_LEN(option_ptr) ((option_ptr->flags_plus_len & 0x1F) << 2)
#define GENEVE_SINGLE_OPT_TOTAL_LEN(option_ptr) \
(GENEVE_MIN_SINGLE_OPT_LEN + GENEVE_SINGLE_OPT_LEN(option_ptr))
#define GENEVE_MAX_PORTS 4
#define GENEVE_UNSET_PORT -1
#define GENEVE_DEFAULT_PORT 6081
#define GENEVE_DEFAULT_PORT_S "6081"
static bool g_geneve_enabled = true;
static int g_geneve_ports_idx = 0;
static int g_geneve_ports[GENEVE_MAX_PORTS] = { GENEVE_DEFAULT_PORT, GENEVE_UNSET_PORT,
GENEVE_UNSET_PORT, GENEVE_UNSET_PORT };
/* Geneve structs based on diagrams from the following specification doc:
* https://tools.ietf.org/html/draft-ietf-nvo3-geneve-16#section-3 */
typedef struct GeneveOption_ {
uint16_t option_class;
uint8_t type;
uint8_t flags_plus_len;
uint8_t option_data[0];
} GeneveOption;
typedef struct GeneveHeader_ {
uint8_t ver_plus_len;
uint8_t flags;
uint16_t eth_type;
uint8_t vni[3];
uint8_t res;
GeneveOption options[0];
} GeneveHeader;
bool DecodeGeneveEnabledForPort(const uint16_t sp, const uint16_t dp)
{
SCLogDebug("ports %u->%u ports %d %d %d %d", sp, dp, g_geneve_ports[0], g_geneve_ports[1],
g_geneve_ports[2], g_geneve_ports[3]);
if (g_geneve_enabled) {
for (int i = 0; i < g_geneve_ports_idx; i++) {
if (g_geneve_ports[i] == GENEVE_UNSET_PORT)
return false;
const int port = g_geneve_ports[i];
if (port == (const int)sp || port == (const int)dp)
return true;
}
}
return false;
}
static void DecodeGeneveConfigPorts(const char *pstr)
{
SCLogDebug("parsing \'%s\'", pstr);
DetectPort *head = NULL;
DetectPortParse(NULL, &head, pstr);
g_geneve_ports_idx = 0;
for (DetectPort *p = head; p != NULL; p = p->next) {
if (g_geneve_ports_idx >= GENEVE_MAX_PORTS) {
SCLogWarning(SC_ERR_INVALID_YAML_CONF_ENTRY, "more than %d Geneve ports defined",
GENEVE_MAX_PORTS);
break;
}
g_geneve_ports[g_geneve_ports_idx++] = (int)p->port;
}
DetectPortCleanupList(NULL, head);
}
void DecodeGeneveConfig(void)
{
int enabled = 0;
if (ConfGetBool("decoder.geneve.enabled", &enabled) == 1) {
if (enabled) {
g_geneve_enabled = true;
} else {
g_geneve_enabled = false;
}
}
if (g_geneve_enabled) {
ConfNode *node = ConfGetNode("decoder.geneve.ports");
if (node && node->val) {
DecodeGeneveConfigPorts(node->val);
} else {
DecodeGeneveConfigPorts(GENEVE_DEFAULT_PORT_S);
}
}
}
static inline bool IsValidGeneveVersion(const GeneveHeader *geneve_hdr)
{
const int valid_verisons[] = VALID_GENEVE_VERSIONS;
const int num_versions = sizeof(valid_verisons) / sizeof(int);
const uint8_t cur_version = GENEVE_VERSION(geneve_hdr);
for (int i = 0; i < num_versions; i++) {
if (valid_verisons[i] == cur_version)
return true;
}
return false;
}
/* Performs a check to ensure that option lens add up to total length specified in the fixed header
*/
static inline bool IsHeaderLengthConsistentWithOptions(const GeneveHeader *geneve_hdr)
{
uint8_t *geneve_opt_ptr = (uint8_t *)geneve_hdr->options;
int remaining_hdr_len = GENEVE_TOTAL_OPT_LEN(geneve_hdr);
while (remaining_hdr_len > 0) {
const GeneveOption *cur_opt = (const GeneveOption *)geneve_opt_ptr;
const uint8_t cur_option_len = GENEVE_SINGLE_OPT_TOTAL_LEN(cur_opt);
geneve_opt_ptr += cur_option_len;
remaining_hdr_len -=
cur_option_len; /* cur_option_len will always be between 4-128, inclusive */
}
return (remaining_hdr_len == 0);
}
/** \param pkt payload data directly above UDP header
* \param len length in bytes of pkt
*/
int DecodeGeneve(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, const uint8_t *pkt, uint32_t len)
{
DEBUG_VALIDATE_BUG_ON(pkt == NULL);
const GeneveHeader *geneve_hdr = (const GeneveHeader *)pkt;
uint16_t eth_type, geneve_hdr_len;
int decode_tunnel_proto = DECODE_TUNNEL_UNSET;
/* General Geneve packet validation */
if (unlikely(!g_geneve_enabled))
return TM_ECODE_FAILED;
if (unlikely(len < GENEVE_MIN_HEADER_LEN))
return TM_ECODE_FAILED;
if (!PacketIncreaseCheckLayers(p)) {
return TM_ECODE_FAILED;
}
/* Specific Geneve header field validation */
geneve_hdr_len = GENEVE_TOTAL_HEADER_LEN(geneve_hdr);
if (len < geneve_hdr_len)
return TM_ECODE_FAILED;
if (!IsValidGeneveVersion(geneve_hdr))
return TM_ECODE_FAILED;
if (GENEVE_RESERVED_FLAGS(geneve_hdr) != 0 || geneve_hdr->res != 0)
return TM_ECODE_FAILED;
if (!IsHeaderLengthConsistentWithOptions(geneve_hdr))
return TM_ECODE_FAILED;
#if DEBUG
/* Print the VNI for debugging purposes */
uint32_t vni = (geneve_hdr->vni[0] << 16) + (geneve_hdr->vni[1] << 8) + (geneve_hdr->vni[2]);
SCLogDebug("Geneve vni %u", vni);
#endif
/* Increment stats counter for Geneve packets */
StatsIncr(tv, dtv->counter_geneve);
/* Determine first protocol encapsulated after Geneve header */
eth_type = SCNtohs(geneve_hdr->eth_type);
SCLogDebug("Geneve ethertype 0x%04x", eth_type);
switch (eth_type) {
case ETHERNET_TYPE_IP:
SCLogDebug("Geneve found IPv4");
decode_tunnel_proto = DECODE_TUNNEL_IPV4;
break;
case ETHERNET_TYPE_IPV6:
SCLogDebug("Geneve found IPv6");
decode_tunnel_proto = DECODE_TUNNEL_IPV6;
break;
case ETHERNET_TYPE_BRIDGE:
SCLogDebug("Geneve found Ethernet");
decode_tunnel_proto = DECODE_TUNNEL_ETHERNET;
break;
case ETHERNET_TYPE_ARP:
SCLogDebug("Geneve found ARP");
break;
default:
SCLogDebug(
"Geneve found unsupported Ethertype - expected IPv4, IPv6, ARP, or Ethernet");
ENGINE_SET_INVALID_EVENT(p, GENEVE_UNKNOWN_PAYLOAD_TYPE);
}
/* Set-up and process inner packet if it is a supported ethertype */
if (decode_tunnel_proto != DECODE_TUNNEL_UNSET) {
Packet *tp = PacketTunnelPktSetup(
tv, dtv, p, pkt + geneve_hdr_len, len - geneve_hdr_len, decode_tunnel_proto);
if (tp != NULL) {
PKT_SET_SRC(tp, PKT_SRC_DECODER_GENEVE);
PacketEnqueueNoLock(&tv->decode_pq, tp);
}
}
return TM_ECODE_OK;
}
#ifdef UNITTESTS
/**
* \test DecodeGeneveTest01 tests a good Geneve header with 16-bytes of options.
* Contains a Ethernet+IPv6 DHCP request packet.
*/
static int DecodeGeneveTest01(void)
{
uint8_t raw_geneve[] = { 0x32, 0x10, 0x17, 0xc1, 0x00, 0xc1, 0x87, 0x51, /* UDP header */
0x04, 0x00, 0x65, 0x58, 0x00, 0x00, 0x25, 0x00, /* Geneve fixed header */
0x01, 0x08, 0x00, 0x01, 0x11, 0x11, 0x11, 0x11, /* Geneve variable options */
0x01, 0x08, 0x00, 0x01, 0x11, 0x11, 0x11, 0x11, /* Geneve variable options */
0x33, 0x33, 0x00, 0x01, 0x00, 0x02, /* inner destination MAC */
0x08, 0x00, 0x27, 0xfe, 0x8f, 0x95, /* inner source MAC */
0x86, 0xdd, /* type is IPv6 0x86dd */
0x60, 0x00, 0x00, 0x00, 0x00, 0x6b, 0x11, 0x01, /* IPv6 hdr */
0xfe, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0a, 0x00, 0x27, 0xff, 0xfe, 0xfe, 0x8f,
0x95, 0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
0x00, 0x02, 0x02, 0x22, 0x02, 0x23, 0x00, 0x6b, 0x9c, 0xfb, /* UDP src port 546 */
0x03, 0x49, 0x17, 0x4e, 0x00, 0x01, 0x00, 0x0e, /* DHCP request payload */
0x00, 0x01, 0x00, 0x01, 0x1c, 0x39, 0xcf, 0x88, 0x08, 0x00, 0x27, 0xfe, 0x8f, 0x95, 0x00,
0x02, 0x00, 0x0e, 0x00, 0x01, 0x00, 0x01, 0x1c, 0x38, 0x25, 0xe8, 0x08, 0x00, 0x27, 0xd4,
0x10, 0xbb, 0x00, 0x06, 0x00, 0x04, 0x00, 0x17, 0x00, 0x18, 0x00, 0x08, 0x00, 0x02, 0x00,
0x00, 0x00, 0x19, 0x00, 0x29, 0x27, 0xfe, 0x8f, 0x95, 0x00, 0x00, 0x0e, 0x10, 0x00, 0x00,
0x15, 0x18, 0x00, 0x1a, 0x00, 0x19, 0x00, 0x00, 0x1c, 0x20, 0x00, 0x00, 0x1d, 0x4c, 0x40,
0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0xfe, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00 };
Packet *p = PacketGetFromAlloc();
FAIL_IF_NULL(p);
ThreadVars tv;
DecodeThreadVars dtv;
DecodeGeneveConfigPorts(GENEVE_DEFAULT_PORT_S);
memset(&tv, 0, sizeof(ThreadVars));
memset(p, 0, SIZE_OF_PACKET);
memset(&dtv, 0, sizeof(DecodeThreadVars));
FlowInitConfig(FLOW_QUIET);
DecodeUDP(&tv, &dtv, p, raw_geneve, sizeof(raw_geneve));
FAIL_IF(p->udph == NULL);
FAIL_IF(tv.decode_pq.top == NULL);
Packet *tp = PacketDequeueNoLock(&tv.decode_pq);
FAIL_IF(tp->udph == NULL);
FAIL_IF_NOT(tp->sp == 546);
FlowShutdown();
PacketFree(p);
PacketFree(tp);
PASS;
}
/**
* \test DecodeGeneveTest02 tests a good Geneve header with 16-bytes of options.
* Contains a IPv4 DNS request packet.
*/
static int DecodeGeneveTest02(void)
{
uint8_t raw_geneve[] = {
0x32, 0x10, 0x17, 0xc1, 0x00, 0x3c, 0x87, 0x51, /* UDP header */
0x04, 0x00, 0x08, 0x00, 0x00, 0x00, 0x25, 0x00, /* Geneve fixed header */
0x01, 0x08, 0x00, 0x01, 0x11, 0x11, 0x11, 0x11, /* Geneve variable options */
0x01, 0x08, 0x00, 0x01, 0x11, 0x11, 0x11, 0x11, /* Geneve variable options */
0x45, 0x00, 0x00, 0x1c, 0x00, 0x01, 0x00, 0x00, 0x40, 0x11, /* IPv4 hdr */
0x44, 0x45, 0x0a, 0x60, 0x00, 0x0a, 0xb9, 0x1b, 0x73, 0x06, 0x00, 0x35, 0x30, 0x39, 0x00,
0x08, 0x98, 0xe4 /* UDP probe src port 53 */
};
Packet *p = PacketGetFromAlloc();
FAIL_IF_NULL(p);
ThreadVars tv;
DecodeThreadVars dtv;
DecodeGeneveConfigPorts(GENEVE_DEFAULT_PORT_S);
memset(&tv, 0, sizeof(ThreadVars));
memset(p, 0, SIZE_OF_PACKET);
memset(&dtv, 0, sizeof(DecodeThreadVars));
FlowInitConfig(FLOW_QUIET);
DecodeUDP(&tv, &dtv, p, raw_geneve, sizeof(raw_geneve));
FAIL_IF(p->udph == NULL);
FAIL_IF(tv.decode_pq.top == NULL);
Packet *tp = PacketDequeueNoLock(&tv.decode_pq);
FAIL_IF(tp->udph == NULL);
FAIL_IF_NOT(tp->sp == 53);
FlowShutdown();
PacketFree(p);
PacketFree(tp);
PASS;
}
/**
* \test DecodeGeneveTest03 tests a good Geneve header with 16-bytes of options.
* Contains a IPv4 DNS request packet with a VLAN tag after the Ethernet frame.
* In practice, this probably won't be used but it should be support either way.
*/
static int DecodeGeneveTest03(void)
{
uint8_t raw_geneve[] = {
0x32, 0x10, 0x17, 0xc1, 0x00, 0x4e, 0x87, 0x51, /* UDP header */
0x04, 0x00, 0x65, 0x58, 0x00, 0x00, 0x25, 0x00, /* Geneve fixed header */
0x01, 0x08, 0x00, 0x01, 0x11, 0x11, 0x11, 0x11, /* Geneve variable options */
0x01, 0x08, 0x00, 0x01, 0x11, 0x11, 0x11, 0x11, /* Geneve variable options */
0x33, 0x33, 0x00, 0x01, 0x00, 0x02, /* inner destination MAC */
0x08, 0x00, 0x27, 0xfe, 0x8f, 0x95, /* inner source MAC */
0x81, 0x00, 0x00, 0xad, /* 802.1Q VLAN tag */
0x08, 0x00, /* type is IPv4 0x0800 */
0x45, 0x00, 0x00, 0x1c, 0x00, 0x01, 0x00, 0x00, 0x40, 0x11, /* IPv4 hdr */
0x44, 0x45, 0x0a, 0x60, 0x00, 0x0a, 0xb9, 0x1b, 0x73, 0x06, 0x00, 0x35, 0x30, 0x39, 0x00,
0x08, 0x98, 0xe4 /* UDP probe src port 53 */
};
Packet *p = PacketGetFromAlloc();
FAIL_IF_NULL(p);
ThreadVars tv;
DecodeThreadVars dtv;
DecodeGeneveConfigPorts(GENEVE_DEFAULT_PORT_S);
memset(&tv, 0, sizeof(ThreadVars));
memset(p, 0, SIZE_OF_PACKET);
memset(&dtv, 0, sizeof(DecodeThreadVars));
FlowInitConfig(FLOW_QUIET);
DecodeUDP(&tv, &dtv, p, raw_geneve, sizeof(raw_geneve));
FAIL_IF(p->udph == NULL);
FAIL_IF(tv.decode_pq.top == NULL);
Packet *tp = PacketDequeueNoLock(&tv.decode_pq);
FAIL_IF(tp->udph == NULL);
FAIL_IF_NOT(tp->sp == 53);
FlowShutdown();
PacketFree(p);
PacketFree(tp);
PASS;
}
/**
* \test DecodeGeneveTest04 tests default port disabled by the config.
*/
static int DecodeGeneveTest04(void)
{
uint8_t raw_geneve[] = {
0x32, 0x10, 0x17, 0xc1, 0x00, 0x4a, 0x87, 0x51, /* UDP header */
0x04, 0x00, 0x65, 0x58, 0x00, 0x00, 0x25, 0x00, /* Geneve fixed header */
0x01, 0x08, 0x00, 0x01, 0x11, 0x11, 0x11, 0x11, /* Geneve variable options */
0x01, 0x08, 0x00, 0x01, 0x11, 0x11, 0x11, 0x11, /* Geneve variable options */
0x10, 0x00, 0x00, 0x0c, 0x01, 0x00, /* inner destination MAC */
0x00, 0x51, 0x52, 0xb3, 0x54, 0xe5, /* inner source MAC */
0x08, 0x00, /* type is IPv4 0x0800 */
0x45, 0x00, 0x00, 0x1c, 0x00, 0x01, 0x00, 0x00, 0x40, 0x11, /* IPv4 hdr */
0x44, 0x45, 0x0a, 0x60, 0x00, 0x0a, 0xb9, 0x1b, 0x73, 0x06, 0x00, 0x35, 0x30, 0x39, 0x00,
0x08, 0x98, 0xe4 /* UDP probe src port 53 */
};
Packet *p = PacketGetFromAlloc();
FAIL_IF_NULL(p);
ThreadVars tv;
DecodeThreadVars dtv;
DecodeGeneveConfigPorts("1"); /* Set Suricata to use a non-default port for Geneve*/
memset(&tv, 0, sizeof(ThreadVars));
memset(p, 0, SIZE_OF_PACKET);
memset(&dtv, 0, sizeof(DecodeThreadVars));
FlowInitConfig(FLOW_QUIET);
DecodeUDP(&tv, &dtv, p, raw_geneve, sizeof(raw_geneve));
FAIL_IF(p->udph == NULL);
FAIL_IF(tv.decode_pq.top != NULL); /* Geneve packet should not have been processed */
DecodeGeneveConfigPorts(GENEVE_DEFAULT_PORT_S); /* Reset Geneve port list for future calls */
FlowShutdown();
PacketFree(p);
PASS;
}
/**
* \test DecodeGeneveTest05 tests if Geneve header has inconsistent option len values.
*/
static int DecodeGeneveTest05(void)
{
uint8_t raw_geneve[] = {
0x32, 0x10, 0x17, 0xc1, 0x00, 0x4a, 0x87, 0x51, /* UDP header */
0x04, 0x00, 0x65, 0x58, 0x00, 0x00, 0x25, 0x00, /* Geneve fixed header */
0x01, 0x08, 0x00, 0x04, 0x11, 0x11, 0x11, 0x11, /* Geneve variable options */
0x01, 0x08, 0x00, 0x01, 0x11, 0x11, 0x11, 0x11, /* Geneve variable options */
0x10, 0x00, 0x00, 0x0c, 0x01, 0x00, /* inner destination MAC */
0x00, 0x51, 0x52, 0xb3, 0x54, 0xe5, /* inner source MAC */
0x08, 0x00, /* type is IPv4 0x0800 */
0x45, 0x00, 0x00, 0x1c, 0x00, 0x01, 0x00, 0x00, 0x40, 0x11, /* IPv4 hdr */
0x44, 0x45, 0x0a, 0x60, 0x00, 0x0a, 0xb9, 0x1b, 0x73, 0x06, 0x00, 0x35, 0x30, 0x39, 0x00,
0x08, 0x98, 0xe4 /* UDP probe src port 53 */
};
Packet *p = PacketGetFromAlloc();
FAIL_IF_NULL(p);
ThreadVars tv;
DecodeThreadVars dtv;
DecodeGeneveConfigPorts(GENEVE_DEFAULT_PORT_S);
memset(&tv, 0, sizeof(ThreadVars));
memset(p, 0, SIZE_OF_PACKET);
memset(&dtv, 0, sizeof(DecodeThreadVars));
FlowInitConfig(FLOW_QUIET);
DecodeUDP(&tv, &dtv, p, raw_geneve, sizeof(raw_geneve));
FAIL_IF(p->udph == NULL);
FAIL_IF(tv.decode_pq.top != NULL); /* Geneve packet should not have been processed */
FlowShutdown();
PacketFree(p);
PASS;
}
#endif /* UNITTESTS */
void DecodeGeneveRegisterTests(void)
{
#ifdef UNITTESTS
UtRegisterTest("DecodeGeneveTest01 -- Ethernet+IPv6 DHCP Request", DecodeGeneveTest01);
UtRegisterTest("DecodeGeneveTest02 -- IPv4 DNS Request", DecodeGeneveTest02);
UtRegisterTest("DecodeGeneveTest03 -- VLAN+IPv4 DNS Request", DecodeGeneveTest03);
UtRegisterTest("DecodeGeneveTest04 -- Non-standard port configuration", DecodeGeneveTest04);
UtRegisterTest("DecodeGeneveTest05 -- Inconsistent Geneve hdr option lens", DecodeGeneveTest05);
#endif /* UNITTESTS */
}