1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
/* Copyright (C) 2007-2019 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 Victor Julien <victor@inliniac.net>
*
*/
#include "suricata-common.h"
#include "detect.h"
#include "detect-parse.h"
#include "detect-engine.h"
#include "detect-engine-mpm.h"
#include "detect-engine-prefilter.h"
#include "detect-engine-content-inspection.h"
#include "detect-fast-pattern.h"
#include "detect-tcphdr.h"
/* prototypes */
static int DetectTcphdrSetup (DetectEngineCtx *, Signature *, const char *);
#ifdef UNITTESTS
void DetectTcphdrRegisterTests (void);
#endif
static int g_tcphdr_buffer_id = 0;
static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
const DetectEngineTransforms *transforms, Packet *p, const int list_id);
/**
* \brief Registration function for tcp.hdr: keyword
*/
void DetectTcphdrRegister(void)
{
sigmatch_table[DETECT_TCPHDR].name = "tcp.hdr";
sigmatch_table[DETECT_TCPHDR].desc = "sticky buffer to match on the TCP header";
sigmatch_table[DETECT_TCPHDR].url = "/rules/header-keywords.html#tcphdr";
sigmatch_table[DETECT_TCPHDR].Setup = DetectTcphdrSetup;
sigmatch_table[DETECT_TCPHDR].flags |= SIGMATCH_NOOPT | SIGMATCH_INFO_STICKY_BUFFER;
#ifdef UNITTESTS
sigmatch_table[DETECT_TCPHDR].RegisterTests = DetectTcphdrRegisterTests;
#endif
g_tcphdr_buffer_id = DetectBufferTypeRegister("tcp.hdr");
BUG_ON(g_tcphdr_buffer_id < 0);
DetectBufferTypeSupportsPacket("tcp.hdr");
DetectPktMpmRegister("tcp.hdr", 2, PrefilterGenericMpmPktRegister, GetData);
DetectPktInspectEngineRegister("tcp.hdr", GetData,
DetectEngineInspectPktBufferGeneric);
return;
}
/**
* \brief setup tcp.hdr sticky buffer
*
* \param de_ctx pointer to the Detection Engine Context
* \param s pointer to the Current Signature
* \param _unused unused
*
* \retval 0 on Success
* \retval -1 on Failure
*/
static int DetectTcphdrSetup (DetectEngineCtx *de_ctx, Signature *s, const char *_unused)
{
if (!(DetectProtoContainsProto(&s->proto, IPPROTO_TCP)))
return -1;
s->flags |= SIG_FLAG_REQUIRE_PACKET;
if (DetectBufferSetActiveList(de_ctx, s, g_tcphdr_buffer_id) < 0)
return -1;
return 0;
}
static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
const DetectEngineTransforms *transforms, Packet *p, const int list_id)
{
SCEnter();
InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
if (buffer->inspect == NULL) {
if (p->tcph == NULL) {
// may happen when DecodeTCPPacket fails
// for instance with invalid header length
return NULL;
}
uint32_t hlen = TCP_GET_HLEN(p);
if (((uint8_t *)p->tcph + (ptrdiff_t)hlen) >
((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)))
{
SCLogDebug("data out of range: %p > %p",
((uint8_t *)p->tcph + (ptrdiff_t)hlen),
((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)));
return NULL;
}
const uint32_t data_len = hlen;
const uint8_t *data = (const uint8_t *)p->tcph;
InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);
InspectionBufferApplyTransforms(buffer, transforms);
}
return buffer;
}
#ifdef UNITTESTS
#include "tests/detect-tcphdr.c"
#endif
|
