suricata
detect-udphdr.c
Go to the documentation of this file.
1 /* Copyright (C) 2007-2019 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 Victor Julien <victor@inliniac.net>
22  *
23  */
24 
25 #include "suricata-common.h"
26 
27 #include "detect.h"
28 #include "detect-parse.h"
29 #include "detect-engine.h"
30 #include "detect-engine-buffer.h"
31 #include "detect-engine-mpm.h"
34 #include "detect-fast-pattern.h"
35 #include "detect-udphdr.h"
36 
37 /* prototypes */
38 static int DetectUdphdrSetup (DetectEngineCtx *, Signature *, const char *);
39 #ifdef UNITTESTS
40 void DetectUdphdrRegisterTests (void);
41 #endif
42 
43 static int g_udphdr_buffer_id = 0;
44 
45 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
46  const DetectEngineTransforms *transforms, Packet *p, const int list_id);
47 /**
48  * \brief Registration function for udp.hdr: keyword
49  */
51 {
52  sigmatch_table[DETECT_UDPHDR].name = "udp.hdr";
53  sigmatch_table[DETECT_UDPHDR].desc = "sticky buffer to match on the UDP header";
54  sigmatch_table[DETECT_UDPHDR].url = "/rules/header-keywords.html#udphdr";
55  sigmatch_table[DETECT_UDPHDR].Setup = DetectUdphdrSetup;
57 #ifdef UNITTESTS
59 #endif
60 
61  g_udphdr_buffer_id = DetectBufferTypeRegister("udp.hdr");
62  BUG_ON(g_udphdr_buffer_id < 0);
63 
65 
67 
69 }
70 
71 /**
72  * \brief set up the udp.hdr sticky buffer
73  *
74  * \param de_ctx pointer to the Detection Engine Context
75  * \param s pointer to the Current Signature
76  * \param _unused unused
77  *
78  * \retval 0 on Success
79  * \retval -1 on Failure
80  */
81 static int DetectUdphdrSetup (DetectEngineCtx *de_ctx, Signature *s, const char *_unused)
82 {
83  if (!(DetectProtoContainsProto(&s->proto, IPPROTO_UDP)))
84  return -1;
85 
87 
88  if (SCDetectBufferSetActiveList(de_ctx, s, g_udphdr_buffer_id) < 0)
89  return -1;
90 
91  return 0;
92 }
93 
94 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
95  const DetectEngineTransforms *transforms, Packet *p, const int list_id)
96 {
97  SCEnter();
98 
99  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
100  if (buffer->inspect == NULL) {
101  if (!PacketIsUDP(p)) {
102  return NULL;
103  }
104  const UDPHdr *udph = PacketGetUDP(p);
105  if (((uint8_t *)udph + (ptrdiff_t)UDP_HEADER_LEN) >
106  ((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p))) {
107  SCLogDebug("data out of range: %p > %p", ((uint8_t *)udph + (ptrdiff_t)UDP_HEADER_LEN),
108  ((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)));
109  return NULL;
110  }
111 
112  const uint32_t data_len = UDP_HEADER_LEN;
113  const uint8_t *data = (const uint8_t *)udph;
114 
116  det_ctx, list_id, buffer, data, data_len, transforms);
117  }
118 
119  return buffer;
120 }
121 
122 #ifdef UNITTESTS
123 #include "tests/detect-udphdr.c"
124 #endif
PrefilterGenericMpmPktRegister
int PrefilterGenericMpmPktRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, const DetectBufferMpmRegistry *mpm_reg, int list_id)
Definition: detect-engine-prefilter.c:1670
SigTableElmt_::url
const char * url
Definition: detect.h:1431
detect-engine.h
SIGMATCH_INFO_STICKY_BUFFER
#define SIGMATCH_INFO_STICKY_BUFFER
Definition: detect.h:1645
SigTableElmt_::desc
const char * desc
Definition: detect.h:1430
sigmatch_table
SigTableElmt * sigmatch_table
Definition: detect-parse.c:155
SigTableElmt_::name
const char * name
Definition: detect.h:1428
InspectionBufferSetupAndApplyTransforms
void InspectionBufferSetupAndApplyTransforms(DetectEngineThreadCtx *det_ctx, const int list_id, InspectionBuffer *buffer, const uint8_t *data, const uint32_t data_len, const DetectEngineTransforms *transforms)
setup the buffer with our initial data
Definition: detect-engine.c:1570
DetectEngineTransforms
Definition: detect.h:415
SCLogDebug
#define SCLogDebug(...)
Definition: util-debug.h:269
DetectPktMpmRegister
void DetectPktMpmRegister(const char *name, int priority, int(*PrefilterRegister)(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, const DetectBufferMpmRegistry *mpm_reg, int list_id), InspectionBufferGetPktDataPtr GetData)
register a MPM engine
Definition: detect-engine-mpm.c:541
InspectionBuffer
Definition: detect.h:380
SigTableElmt_::flags
uint16_t flags
Definition: detect.h:1422
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:931
DETECT_UDPHDR
@ DETECT_UDPHDR
Definition: detect-engine-register.h:290
SCDetectBufferSetActiveList
int SCDetectBufferSetActiveList(DetectEngineCtx *de_ctx, Signature *s, const int list)
Definition: detect-engine-buffer.c:29
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1413
detect-engine-prefilter.h
InspectionBufferGet
InspectionBuffer * InspectionBufferGet(DetectEngineThreadCtx *det_ctx, const int list_id)
Definition: detect-engine.c:1429
DetectBufferTypeSupportsPacket
void DetectBufferTypeSupportsPacket(const char *name)
Definition: detect-engine.c:1127
detect-udphdr.h
de_ctx
DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:18
DetectEngineThreadCtx_
Definition: detect.h:1223
DetectPktInspectEngineRegister
void DetectPktInspectEngineRegister(const char *name, InspectionBufferGetPktDataPtr GetPktData, InspectionBufferPktInspectFunc Callback)
register inspect engine at start up time
Definition: detect-engine.c:135
SCEnter
#define SCEnter(...)
Definition: util-debug.h:271
GET_PKT_DATA
#define GET_PKT_DATA(p)
Definition: decode.h:209
detect-engine-mpm.h
detect.h
BUG_ON
#define BUG_ON(x)
Definition: suricata-common.h:317
Signature_::flags
uint32_t flags
Definition: detect.h:671
Packet_
Definition: decode.h:492
DetectUdphdrRegister
void DetectUdphdrRegister(void)
Registration function for udp.hdr: keyword.
Definition: detect-udphdr.c:50
GET_PKT_LEN
#define GET_PKT_LEN(p)
Definition: decode.h:208
detect-udphdr.c
detect-engine-content-inspection.h
detect-fast-pattern.h
DetectBufferTypeRegister
int DetectBufferTypeRegister(const char *name)
Definition: detect-engine.c:1093
Signature_::proto
DetectProto proto
Definition: detect.h:689
suricata-common.h
detect-engine-buffer.h
UDPHdr_
Definition: decode-udp.h:42
InspectionBuffer::inspect
const uint8_t * inspect
Definition: detect.h:381
detect-parse.h
Signature_
Signature container.
Definition: detect.h:670
DetectUdphdrRegisterTests
void DetectUdphdrRegisterTests(void)
this function registers unit tests for DetectUdphdr
Definition: detect-udphdr.c:44
UDP_HEADER_LEN
#define UDP_HEADER_LEN
Definition: decode-udp.h:27
SIGMATCH_NOOPT
#define SIGMATCH_NOOPT
Definition: detect.h:1620
DetectEngineInspectPktBufferGeneric
int DetectEngineInspectPktBufferGeneric(DetectEngineThreadCtx *det_ctx, const DetectEnginePktInspectionEngine *engine, const Signature *s, Packet *p, uint8_t *_alert_flags)
Do the content inspection & validation for a signature.
Definition: detect-engine.c:2234
SigTableElmt_::RegisterTests
void(* RegisterTests)(void)
Definition: detect.h:1420
DetectProtoContainsProto
int DetectProtoContainsProto(const DetectProto *dp, int proto)
see if a DetectProto contains a certain proto
Definition: detect-engine-proto.c:135
SIG_FLAG_REQUIRE_PACKET
#define SIG_FLAG_REQUIRE_PACKET
Definition: detect.h:253