suricata
detect-tls-sni.c
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1 /* Copyright (C) 2007-2016 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 Mats Klepsland <mats.klepsland@gmail.com>
22  *
23  * Implements support for tls.sni keyword.
24  */
25 
26 #include "suricata-common.h"
27 #include "threads.h"
28 #include "decode.h"
29 #include "detect.h"
30 
31 #include "detect-parse.h"
32 #include "detect-engine.h"
33 #include "detect-engine-mpm.h"
34 #include "detect-content.h"
35 #include "detect-pcre.h"
36 
37 #include "flow.h"
38 #include "flow-util.h"
39 #include "flow-var.h"
40 
41 #include "util-debug.h"
42 #include "util-spm.h"
43 #include "util-print.h"
44 
45 #include "stream-tcp.h"
46 
47 #include "app-layer.h"
48 #include "app-layer-ssl.h"
50 #include "detect-tls-sni.h"
51 
52 #include "util-unittest.h"
53 #include "util-unittest-helper.h"
54 
55 static int DetectTlsSniSetup(DetectEngineCtx *, Signature *, const char *);
56 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
57  const DetectEngineTransforms *transforms,
58  Flow *f, const uint8_t flow_flags,
59  void *txv, const int list_id);
60 static int g_tls_sni_buffer_id = 0;
61 
62 /**
63  * \brief Registration function for keyword: tls.sni
64  */
66 {
70  "sticky buffer to match specifically and only on the TLS SNI buffer";
71  sigmatch_table[DETECT_AL_TLS_SNI].url = "/rules/tls-keywords.html#tls-sni";
72  sigmatch_table[DETECT_AL_TLS_SNI].Setup = DetectTlsSniSetup;
75 
78 
81 
83  "TLS Server Name Indication (SNI) extension");
84 
85  g_tls_sni_buffer_id = DetectBufferTypeGetByName("tls.sni");
86 }
87 
88 
89 /**
90  * \brief this function setup the tls.sni modifier keyword used in the rule
91  *
92  * \param de_ctx Pointer to the Detection Engine Context
93  * \param s Pointer to the Signature to which the current keyword belongs
94  * \param str Should hold an empty string always
95  *
96  * \retval 0 On success
97  * \retval -1 On failure
98  */
99 static int DetectTlsSniSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
100 {
101  if (DetectBufferSetActiveList(s, g_tls_sni_buffer_id) < 0)
102  return -1;
103 
105  return -1;
106 
107  return 0;
108 }
109 
110 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
111  const DetectEngineTransforms *transforms, Flow *f,
112  const uint8_t flow_flags, void *txv, const int list_id)
113 {
114  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
115  if (buffer->inspect == NULL) {
116  const SSLState *ssl_state = (SSLState *)f->alstate;
117 
118  if (ssl_state->client_connp.sni == NULL) {
119  return NULL;
120  }
121 
122  const uint32_t data_len = strlen(ssl_state->client_connp.sni);
123  const uint8_t *data = (uint8_t *)ssl_state->client_connp.sni;
124 
125  InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);
126  InspectionBufferApplyTransforms(buffer, transforms);
127  }
128 
129  return buffer;
130 }
SigTableElmt_::url
const char * url
Definition: detect.h:1238
DetectSignatureSetAppProto
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
Definition: detect-parse.c:1493
SSLState_
SSLv[2.0|3.[0|1|2|3]] state structure.
Definition: app-layer-ssl.h:288
detect-content.h
detect-engine.h
SIGMATCH_INFO_STICKY_BUFFER
#define SIGMATCH_INFO_STICKY_BUFFER
Definition: detect.h:1445
SigTableElmt_::desc
const char * desc
Definition: detect.h:1237
DetectEngineInspectBufferGeneric
uint8_t DetectEngineInspectBufferGeneric(DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx, const DetectEngineAppInspectionEngine *engine, const Signature *s, Flow *f, uint8_t flags, void *alstate, void *txv, uint64_t tx_id)
Do the content inspection & validation for a signature.
Definition: detect-engine.c:1994
flow-util.h
SigTableElmt_::name
const char * name
Definition: detect.h:1235
stream-tcp.h
DetectEngineTransforms
Definition: detect.h:371
SSLState_::client_connp
SSLStateConnp client_connp
Definition: app-layer-ssl.h:306
ALPROTO_TLS
@ ALPROTO_TLS
Definition: app-layer-protos.h:33
InspectionBuffer
Definition: detect.h:337
threads.h
Flow_
Flow data structure.
Definition: flow.h:356
PrefilterGenericMpmRegister
int PrefilterGenericMpmRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, const DetectBufferMpmRegistery *mpm_reg, int list_id)
Definition: detect-engine-prefilter.c:749
SigTableElmt_::flags
uint16_t flags
Definition: detect.h:1229
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:784
SSLStateConnp_::sni
char * sni
Definition: app-layer-ssl.h:260
detect-tls-sni.h
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1220
detect-pcre.h
detect-engine-prefilter.h
util-unittest.h
InspectionBufferGet
InspectionBuffer * InspectionBufferGet(DetectEngineThreadCtx *det_ctx, const int list_id)
Definition: detect-engine.c:1369
DetectTlsSniRegister
void DetectTlsSniRegister(void)
Registration function for keyword: tls.sni.
Definition: detect-tls-sni.c:65
util-unittest-helper.h
DetectBufferTypeGetByName
int DetectBufferTypeGetByName(const char *name)
Definition: detect-engine.c:1086
SIG_FLAG_TOSERVER
#define SIG_FLAG_TOSERVER
Definition: detect.h:228
decode.h
util-debug.h
de_ctx
DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:17
DetectEngineThreadCtx_
Definition: detect.h:1024
util-print.h
detect-engine-mpm.h
detect.h
DetectAppLayerInspectEngineRegister2
void DetectAppLayerInspectEngineRegister2(const char *name, AppProto alproto, uint32_t dir, int progress, InspectEngineFuncPtr2 Callback2, InspectionBufferGetDataPtr GetData)
register inspect engine at start up time
Definition: detect-engine.c:228
DetectAppLayerMpmRegister2
void DetectAppLayerMpmRegister2(const char *name, int direction, int priority, int(*PrefilterRegister)(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, const DetectBufferMpmRegistery *mpm_reg, int list_id), InspectionBufferGetDataPtr GetData, AppProto alproto, int tx_min_progress)
register a MPM engine
Definition: detect-engine-mpm.c:89
SigTableElmt_::alias
const char * alias
Definition: detect.h:1236
suricata-common.h
InspectionBufferApplyTransforms
void InspectionBufferApplyTransforms(InspectionBuffer *buffer, const DetectEngineTransforms *transforms)
Definition: detect-engine.c:1552
sigmatch_table
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect-parse.c:76
util-spm.h
InspectionBuffer::inspect
const uint8_t * inspect
Definition: detect.h:338
str
#define str(s)
Definition: suricata-common.h:280
InspectionBufferSetup
void InspectionBufferSetup(DetectEngineThreadCtx *det_ctx, const int list_id, InspectionBuffer *buffer, const uint8_t *data, const uint32_t data_len)
setup the buffer with our initial data
Definition: detect-engine.c:1450
Flow_::alstate
void * alstate
Definition: flow.h:489
detect-parse.h
Signature_
Signature container.
Definition: detect.h:539
DETECT_AL_TLS_SNI
@ DETECT_AL_TLS_SNI
Definition: detect-engine-register.h:225
SIGMATCH_NOOPT
#define SIGMATCH_NOOPT
Definition: detect.h:1421
DetectBufferSetActiveList
int DetectBufferSetActiveList(Signature *s, const int list)
Definition: detect-engine.c:1300
DetectBufferTypeSetDescriptionByName
void DetectBufferTypeSetDescriptionByName(const char *name, const char *desc)
Definition: detect-engine.c:1183
flow.h
flow-var.h
app-layer-ssl.h
app-layer.h