suricata
detect-tcphdr.c
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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-tcphdr.h"
36 
37 /* prototypes */
38 static int DetectTcphdrSetup (DetectEngineCtx *, Signature *, const char *);
39 #ifdef UNITTESTS
40 void DetectTcphdrRegisterTests (void);
41 #endif
42 
43 static int g_tcphdr_buffer_id = 0;
44 
45 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
46  const DetectEngineTransforms *transforms, Packet *p, const int list_id);
47 
48 /**
49  * \brief Registration function for tcp.hdr: keyword
50  */
52 {
53  sigmatch_table[DETECT_TCPHDR].name = "tcp.hdr";
54  sigmatch_table[DETECT_TCPHDR].desc = "sticky buffer to match on the TCP header";
55  sigmatch_table[DETECT_TCPHDR].url = "/rules/header-keywords.html#tcphdr";
56  sigmatch_table[DETECT_TCPHDR].Setup = DetectTcphdrSetup;
58 #ifdef UNITTESTS
60 #endif
61 
62  g_tcphdr_buffer_id = DetectBufferTypeRegister("tcp.hdr");
63  BUG_ON(g_tcphdr_buffer_id < 0);
64 
66 
68 
70 }
71 
72 /**
73  * \brief setup tcp.hdr sticky buffer
74  *
75  * \param de_ctx pointer to the Detection Engine Context
76  * \param s pointer to the Current Signature
77  * \param _unused unused
78  *
79  * \retval 0 on Success
80  * \retval -1 on Failure
81  */
82 static int DetectTcphdrSetup (DetectEngineCtx *de_ctx, Signature *s, const char *_unused)
83 {
84  if (!(DetectProtoContainsProto(&s->proto, IPPROTO_TCP)))
85  return -1;
86 
88 
89  if (SCDetectBufferSetActiveList(de_ctx, s, g_tcphdr_buffer_id) < 0)
90  return -1;
91 
92  return 0;
93 }
94 
95 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
96  const DetectEngineTransforms *transforms, Packet *p, const int list_id)
97 {
98  SCEnter();
99 
100  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
101  if (buffer->inspect == NULL) {
102  if (!PacketIsTCP(p)) {
103  // may happen when DecodeTCPPacket fails
104  // for instance with invalid header length
105  return NULL;
106  }
107  const TCPHdr *tcph = PacketGetTCP(p);
108  const uint32_t hlen = TCP_GET_RAW_HLEN(tcph);
109  if (((uint8_t *)tcph + (ptrdiff_t)hlen) >
110  ((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p))) {
111  SCLogDebug("data out of range: %p > %p", ((uint8_t *)tcph + (ptrdiff_t)hlen),
112  ((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)));
113  return NULL;
114  }
115 
116  const uint32_t data_len = hlen;
117  const uint8_t *data = (const uint8_t *)tcph;
118 
120  det_ctx, list_id, buffer, data, data_len, transforms);
121  }
122 
123  return buffer;
124 }
125 
126 #ifdef UNITTESTS
127 #include "tests/detect-tcphdr.c"
128 #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
detect-tcphdr.c
SigTableElmt_::flags
uint16_t flags
Definition: detect.h:1422
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:931
DetectTcphdrRegisterTests
void DetectTcphdrRegisterTests(void)
this function registers unit tests for DetectTcphdr
Definition: detect-tcphdr.c:44
TCP_GET_RAW_HLEN
#define TCP_GET_RAW_HLEN(tcph)
Definition: decode-tcp.h:72
DetectTcphdrRegister
void DetectTcphdrRegister(void)
Registration function for tcp.hdr: keyword.
Definition: detect-tcphdr.c:51
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_TCPHDR
@ DETECT_TCPHDR
Definition: detect-engine-register.h:289
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
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
GET_PKT_LEN
#define GET_PKT_LEN(p)
Definition: decode.h:208
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
InspectionBuffer::inspect
const uint8_t * inspect
Definition: detect.h:381
detect-tcphdr.h
detect-parse.h
Signature_
Signature container.
Definition: detect.h:670
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
TCPHdr_
Definition: decode-tcp.h:149
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