suricata
decode-vxlan.c
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1 /* Copyright (C) 2019-2021 Open Information Security Foundation
2  *
3  * You can copy, redistribute or modify this Program under the terms of
4  * the GNU General Public License version 2 as published by the Free
5  * Software Foundation.
6  *
7  * This program is distributed in the hope that it will be useful,
8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10  * GNU General Public License for more details.
11  *
12  * You should have received a copy of the GNU General Public License
13  * version 2 along with this program; if not, write to the Free Software
14  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
15  * 02110-1301, USA.
16  */
17 
18 /**
19  * \file
20  *
21  * \author Henrik Kramshoej <hlk@kramse.org>
22  *
23  * VXLAN tunneling scheme decoder.
24  *
25  * This implementation is based on the following specification doc:
26  * https://tools.ietf.org/html/draft-mahalingam-dutt-dcops-vxlan-00
27  */
28 
29 #include "suricata-common.h"
30 #include "decode.h"
31 #include "decode-vxlan.h"
32 #include "decode-events.h"
33 
34 #include "detect.h"
35 #include "detect-engine-port.h"
36 
37 #include "flow.h"
38 
39 #include "util-validate.h"
40 #include "util-unittest.h"
41 #include "util-debug.h"
42 
43 #define VXLAN_HEADER_LEN sizeof(VXLANHeader)
44 
45 #define VXLAN_MAX_PORTS 4
46 #define VXLAN_UNSET_PORT -1
47 #define VXLAN_DEFAULT_PORT 4789
48 #define VXLAN_DEFAULT_PORT_S "4789"
49 
50 static bool g_vxlan_enabled = true;
51 static int g_vxlan_ports_idx = 0;
52 static int g_vxlan_ports[VXLAN_MAX_PORTS] = { VXLAN_DEFAULT_PORT, VXLAN_UNSET_PORT,
54 
55 typedef struct VXLANHeader_ {
56  uint8_t flags[2];
57  uint16_t gdp;
58  uint8_t vni[3];
59  uint8_t res;
61 
62 bool DecodeVXLANEnabledForPort(const uint16_t sp, const uint16_t dp)
63 {
64  SCLogDebug("ports %u->%u ports %d %d %d %d", sp, dp, g_vxlan_ports[0], g_vxlan_ports[1],
65  g_vxlan_ports[2], g_vxlan_ports[3]);
66 
67  if (g_vxlan_enabled) {
68  for (int i = 0; i < g_vxlan_ports_idx; i++) {
69  if (g_vxlan_ports[i] == VXLAN_UNSET_PORT)
70  return false;
71  const int port = g_vxlan_ports[i];
72  if (port == (const int)sp || port == (const int)dp)
73  return true;
74  }
75  }
76  return false;
77 }
78 
79 static void DecodeVXLANConfigPorts(const char *pstr)
80 {
81  SCLogDebug("parsing \'%s\'", pstr);
82 
83  DetectPort *head = NULL;
84  DetectPortParse(NULL, &head, pstr);
85 
86  g_vxlan_ports_idx = 0;
87  for (DetectPort *p = head; p != NULL; p = p->next) {
88  if (g_vxlan_ports_idx >= VXLAN_MAX_PORTS) {
89  SCLogWarning("more than %d VXLAN ports defined", VXLAN_MAX_PORTS);
90  break;
91  }
92  g_vxlan_ports[g_vxlan_ports_idx++] = (int)p->port;
93  }
94 
96 }
97 
99 {
100  int enabled = 0;
101  if (ConfGetBool("decoder.vxlan.enabled", &enabled) == 1) {
102  if (enabled) {
103  g_vxlan_enabled = true;
104  } else {
105  g_vxlan_enabled = false;
106  }
107  }
108 
109  if (g_vxlan_enabled) {
110  ConfNode *node = ConfGetNode("decoder.vxlan.ports");
111  if (node && node->val) {
112  DecodeVXLANConfigPorts(node->val);
113  } else {
114  DecodeVXLANConfigPorts(VXLAN_DEFAULT_PORT_S);
115  }
116  }
117 }
118 
119 /** \param pkt payload data directly above UDP header
120  * \param len length in bytes of pkt
121  */
123  const uint8_t *pkt, uint32_t len)
124 {
125  DEBUG_VALIDATE_BUG_ON(pkt == NULL);
126 
127  /* Initial packet validation */
128  if (unlikely(!g_vxlan_enabled))
129  return TM_ECODE_FAILED;
130 
131  if (len < (VXLAN_HEADER_LEN + sizeof(EthernetHdr)))
132  return TM_ECODE_FAILED;
133  if (!PacketIncreaseCheckLayers(p)) {
134  return TM_ECODE_FAILED;
135  }
136 
137  const VXLANHeader *vxlanh = (const VXLANHeader *)pkt;
138  if ((vxlanh->flags[0] & 0x08) == 0 || vxlanh->res != 0)
139  return TM_ECODE_FAILED;
140 
141 #if DEBUG
142  uint32_t vni = (vxlanh->vni[0] << 16) + (vxlanh->vni[1] << 8) + (vxlanh->vni[2]);
143  SCLogDebug("VXLAN vni %u", vni);
144 #endif
145 
146  /* Increment stats counter for VXLAN packets */
148 
149  EthernetHdr *ethh = (EthernetHdr *)(pkt + VXLAN_HEADER_LEN);
150  int decode_tunnel_proto = DECODE_TUNNEL_UNSET;
151 
152  /* Look at encapsulated Ethernet frame to get next protocol */
153  uint16_t eth_type = SCNtohs(ethh->eth_type);
154  SCLogDebug("VXLAN ethertype 0x%04x", eth_type);
155 
156  switch (eth_type) {
157  case ETHERNET_TYPE_ARP:
158  SCLogDebug("VXLAN found ARP");
159  break;
160  case ETHERNET_TYPE_IP:
161  SCLogDebug("VXLAN found IPv4");
162  decode_tunnel_proto = DECODE_TUNNEL_IPV4;
163  break;
164  case ETHERNET_TYPE_IPV6:
165  SCLogDebug("VXLAN found IPv6");
166  decode_tunnel_proto = DECODE_TUNNEL_IPV6;
167  break;
168  case ETHERNET_TYPE_VLAN:
171  SCLogDebug("VXLAN found VLAN");
172  decode_tunnel_proto = DECODE_TUNNEL_VLAN;
173  break;
174  default:
175  SCLogDebug("VXLAN found unsupported Ethertype - expected IPv4, IPv6, VLAN, or ARP");
177  }
178 
179  /* Set-up and process inner packet if it is a supported ethertype */
180  if (decode_tunnel_proto != DECODE_TUNNEL_UNSET) {
182  len - (VXLAN_HEADER_LEN + ETHERNET_HEADER_LEN), decode_tunnel_proto);
183  if (tp != NULL) {
186  }
187  }
188 
189  return TM_ECODE_OK;
190 }
191 
192 #ifdef UNITTESTS
193 
194 /**
195  * \test DecodeVXLANTest01 test a good vxlan header.
196  * Contains a DNS request packet.
197  */
198 static int DecodeVXLANtest01 (void)
199 {
200  uint8_t raw_vxlan[] = {
201  0x12, 0xb5, 0x12, 0xb5, 0x00, 0x3a, 0x87, 0x51, /* UDP header */
202  0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x25, 0x00, /* VXLAN header */
203  0x10, 0x00, 0x00, 0x0c, 0x01, 0x00, /* inner destination MAC */
204  0x00, 0x51, 0x52, 0xb3, 0x54, 0xe5, /* inner source MAC */
205  0x08, 0x00, /* another IPv4 0x0800 */
206  0x45, 0x00, 0x00, 0x1c, 0x00, 0x01, 0x00, 0x00, 0x40, 0x11,
207  0x44, 0x45, 0x0a, 0x60, 0x00, 0x0a, 0xb9, 0x1b, 0x73, 0x06, /* IPv4 hdr */
208  0x00, 0x35, 0x30, 0x39, 0x00, 0x08, 0x98, 0xe4 /* UDP probe src port 53 */
209  };
210  Packet *p = PacketGetFromAlloc();
211  FAIL_IF_NULL(p);
212  ThreadVars tv;
214  memset(&tv, 0, sizeof(ThreadVars));
215  memset(&dtv, 0, sizeof(DecodeThreadVars));
216 
217  DecodeVXLANConfigPorts(VXLAN_DEFAULT_PORT_S);
219 
220  DecodeUDP(&tv, &dtv, p, raw_vxlan, sizeof(raw_vxlan));
221  FAIL_IF_NOT(PacketIsUDP(p));
222  FAIL_IF(tv.decode_pq.top == NULL);
223 
225  FAIL_IF_NOT(PacketIsUDP(tp));
226  FAIL_IF_NOT(tp->sp == 53);
227 
228  FlowShutdown();
229  PacketFree(p);
231  PASS;
232 }
233 
234 /**
235  * \test DecodeVXLANtest02 tests default port disabled by the config.
236  */
237 static int DecodeVXLANtest02 (void)
238 {
239  uint8_t raw_vxlan[] = {
240  0x12, 0xb5, 0x12, 0xb5, 0x00, 0x3a, 0x87, 0x51, /* UDP header */
241  0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x25, 0x00, /* VXLAN header */
242  0x10, 0x00, 0x00, 0x0c, 0x01, 0x00, /* inner destination MAC */
243  0x00, 0x51, 0x52, 0xb3, 0x54, 0xe5, /* inner source MAC */
244  0x08, 0x00, /* another IPv4 0x0800 */
245  0x45, 0x00, 0x00, 0x1c, 0x00, 0x01, 0x00, 0x00, 0x40, 0x11,
246  0x44, 0x45, 0x0a, 0x60, 0x00, 0x0a, 0xb9, 0x1b, 0x73, 0x06, /* IPv4 hdr */
247  0x00, 0x35, 0x30, 0x39, 0x00, 0x08, 0x98, 0xe4 /* UDP probe src port 53 */
248  };
249  Packet *p = PacketGetFromAlloc();
250  FAIL_IF_NULL(p);
251  ThreadVars tv;
253  memset(&tv, 0, sizeof(ThreadVars));
254  memset(&dtv, 0, sizeof(DecodeThreadVars));
255 
256  DecodeVXLANConfigPorts("1");
258 
259  DecodeUDP(&tv, &dtv, p, raw_vxlan, sizeof(raw_vxlan));
260  FAIL_IF_NOT(PacketIsUDP(p));
261  FAIL_IF(tv.decode_pq.top != NULL);
262 
263  DecodeVXLANConfigPorts(VXLAN_DEFAULT_PORT_S); /* reset */
264  FlowShutdown();
265  PacketFree(p);
266  PASS;
267 }
268 #endif /* UNITTESTS */
269 
271 {
272 #ifdef UNITTESTS
273  UtRegisterTest("DecodeVXLANtest01",
274  DecodeVXLANtest01);
275  UtRegisterTest("DecodeVXLANtest02",
276  DecodeVXLANtest02);
277 #endif /* UNITTESTS */
278 }
VXLANHeader_
Definition: decode-vxlan.c:55
VXLAN_UNSET_PORT
#define VXLAN_UNSET_PORT
Definition: decode-vxlan.c:46
len
uint8_t len
Definition: app-layer-dnp3.h:2
DECODE_TUNNEL_IPV6
@ DECODE_TUNNEL_IPV6
Definition: decode.h:1085
FAIL_IF_NULL
#define FAIL_IF_NULL(expr)
Fail a test if expression evaluates to NULL.
Definition: util-unittest.h:89
decode-vxlan.h
StatsIncr
void StatsIncr(ThreadVars *tv, uint16_t id)
Increments the local counter.
Definition: counters.c:166
DecodeUDP
int DecodeUDP(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, const uint8_t *pkt, uint16_t len)
Definition: decode-udp.c:75
PacketFreeOrRelease
void PacketFreeOrRelease(Packet *p)
Return a packet to where it was allocated.
Definition: decode.c:250
DecodeThreadVars_::counter_vxlan
uint16_t counter_vxlan
Definition: decode.h:985
ConfNode_::val
char * val
Definition: conf.h:34
ConfGetBool
int ConfGetBool(const char *name, int *val)
Retrieve a configuration value as a boolean.
Definition: conf.c:482
unlikely
#define unlikely(expr)
Definition: util-optimize.h:35
UtRegisterTest
void UtRegisterTest(const char *name, int(*TestFn)(void))
Register unit test.
Definition: util-unittest.c:103
SCLogDebug
#define SCLogDebug(...)
Definition: util-debug.h:269
ETHERNET_TYPE_IPV6
#define ETHERNET_TYPE_IPV6
Definition: decode-ethernet.h:39
ConfGetNode
ConfNode * ConfGetNode(const char *name)
Get a ConfNode by name.
Definition: conf.c:181
VXLAN_HEADER_LEN
#define VXLAN_HEADER_LEN
Definition: decode-vxlan.c:43
DecodeVXLANEnabledForPort
bool DecodeVXLANEnabledForPort(const uint16_t sp, const uint16_t dp)
Definition: decode-vxlan.c:62
VXLANHeader_::flags
uint8_t flags[2]
Definition: decode-vxlan.c:56
TM_ECODE_FAILED
@ TM_ECODE_FAILED
Definition: tm-threads-common.h:85
DecodeVXLANConfig
void DecodeVXLANConfig(void)
Definition: decode-vxlan.c:98
util-unittest.h
VXLAN_MAX_PORTS
#define VXLAN_MAX_PORTS
Definition: decode-vxlan.c:45
ETHERNET_TYPE_8021QINQ
#define ETHERNET_TYPE_8021QINQ
Definition: decode-ethernet.h:47
FAIL_IF_NOT
#define FAIL_IF_NOT(expr)
Fail a test if expression evaluates to false.
Definition: util-unittest.h:82
TM_ECODE_OK
@ TM_ECODE_OK
Definition: tm-threads-common.h:84
PKT_SET_SRC
#define PKT_SET_SRC(p, src_val)
Definition: decode.h:1337
FlowInitConfig
void FlowInitConfig(bool quiet)
initialize the configuration
Definition: flow.c:530
DetectPortParse
int DetectPortParse(const DetectEngineCtx *de_ctx, DetectPort **head, const char *str)
Function for parsing port strings.
Definition: detect-engine-port.c:1182
decode.h
util-debug.h
PASS
#define PASS
Pass the test.
Definition: util-unittest.h:105
ETHERNET_TYPE_8021AD
#define ETHERNET_TYPE_8021AD
Definition: decode-ethernet.h:43
PacketDequeueNoLock
Packet * PacketDequeueNoLock(PacketQueueNoLock *qnl)
Definition: packet-queue.c:208
VXLAN_DEFAULT_PORT
#define VXLAN_DEFAULT_PORT
Definition: decode-vxlan.c:47
detect.h
ThreadVars_
Per thread variable structure.
Definition: threadvars.h:57
Packet_::sp
Port sp
Definition: decode.h:489
eth_type
uint16_t eth_type
Definition: decode-ethernet.h:2
PacketFree
void PacketFree(Packet *p)
Return a malloced packet.
Definition: decode.c:193
detect-engine-port.h
SCLogWarning
#define SCLogWarning(...)
Macro used to log WARNING messages.
Definition: util-debug.h:249
DetectPort_
Port structure for detection engine.
Definition: detect.h:217
DECODE_TUNNEL_VLAN
@ DECODE_TUNNEL_VLAN
Definition: decode.h:1083
Packet_
Definition: decode.h:482
VXLANHeader
struct VXLANHeader_ VXLANHeader
DECODE_TUNNEL_IPV4
@ DECODE_TUNNEL_IPV4
Definition: decode.h:1084
ETHERNET_HEADER_LEN
#define ETHERNET_HEADER_LEN
Definition: decode-ethernet.h:27
DecodeVXLAN
int DecodeVXLAN(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, const uint8_t *pkt, uint32_t len)
Definition: decode-vxlan.c:122
decode-events.h
Flow_::next
struct Flow_ * next
Definition: flow.h:405
dtv
DecodeThreadVars * dtv
Definition: fuzz_decodepcapfile.c:33
PacketEnqueueNoLock
void PacketEnqueueNoLock(PacketQueueNoLock *qnl, Packet *p)
Definition: packet-queue.c:168
FAIL_IF
#define FAIL_IF(expr)
Fail a test if expression evaluates to true.
Definition: util-unittest.h:71
SCNtohs
#define SCNtohs(x)
Definition: suricata-common.h:414
suricata-common.h
PacketQueueNoLock_::top
struct Packet_ * top
Definition: packet-queue.h:35
FlowShutdown
void FlowShutdown(void)
shutdown the flow engine
Definition: flow.c:677
VXLANHeader_::vni
uint8_t vni[3]
Definition: decode-vxlan.c:58
VXLANHeader_::res
uint8_t res
Definition: decode-vxlan.c:59
tv
ThreadVars * tv
Definition: fuzz_decodepcapfile.c:32
VXLANHeader_::gdp
uint16_t gdp
Definition: decode-vxlan.c:57
util-validate.h
PacketGetFromAlloc
Packet * PacketGetFromAlloc(void)
Get a malloced packet.
Definition: decode.c:232
PKT_SRC_DECODER_VXLAN
@ PKT_SRC_DECODER_VXLAN
Definition: decode.h:63
DecodeVXLANRegisterTests
void DecodeVXLANRegisterTests(void)
Definition: decode-vxlan.c:270
head
Flow * head
Definition: flow-hash.h:1
DecodeThreadVars_
Structure to hold thread specific data for all decode modules.
Definition: decode.h:946
ConfNode_
Definition: conf.h:32
ETHERNET_TYPE_ARP
#define ETHERNET_TYPE_ARP
Definition: decode-ethernet.h:35
ThreadVars_::decode_pq
PacketQueueNoLock decode_pq
Definition: threadvars.h:111
ENGINE_SET_INVALID_EVENT
#define ENGINE_SET_INVALID_EVENT(p, e)
Definition: decode.h:1171
FLOW_QUIET
#define FLOW_QUIET
Definition: flow.h:43
ETHERNET_TYPE_VLAN
#define ETHERNET_TYPE_VLAN
Definition: decode-vlan.h:31
VXLAN_UNKNOWN_PAYLOAD_TYPE
@ VXLAN_UNKNOWN_PAYLOAD_TYPE
Definition: decode-events.h:196
PacketTunnelPktSetup
Packet * PacketTunnelPktSetup(ThreadVars *tv, DecodeThreadVars *dtv, Packet *parent, const uint8_t *pkt, uint32_t len, enum DecodeTunnelProto proto)
Setup a pseudo packet (tunnel)
Definition: decode.c:367
VXLAN_DEFAULT_PORT_S
#define VXLAN_DEFAULT_PORT_S
Definition: decode-vxlan.c:48
flow.h
ETHERNET_TYPE_IP
#define ETHERNET_TYPE_IP
Definition: decode-ethernet.h:34
DetectPortCleanupList
void DetectPortCleanupList(const DetectEngineCtx *de_ctx, DetectPort *head)
Free a DetectPort list and each of its members.
Definition: detect-engine-port.c:124
DECODE_TUNNEL_UNSET
@ DECODE_TUNNEL_UNSET
Definition: decode.h:1090
DEBUG_VALIDATE_BUG_ON
#define DEBUG_VALIDATE_BUG_ON(exp)
Definition: util-validate.h:102