suricata
detect-tls-sni.c
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1 /* Copyright (C) 2007-2023 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  *
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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-buffer.h"
34 #include "detect-engine-mpm.h"
35 #include "detect-content.h"
36 #include "detect-pcre.h"
37 
38 #include "flow.h"
39 #include "flow-util.h"
40 #include "flow-var.h"
41 
42 #include "util-debug.h"
43 #include "util-spm.h"
44 #include "util-print.h"
45 
46 #include "stream-tcp.h"
47 
48 #include "app-layer.h"
49 #include "app-layer-ssl.h"
51 #include "detect-tls-sni.h"
52 
53 #include "util-unittest.h"
54 #include "util-unittest-helper.h"
55 
56 static int DetectTlsSniSetup(DetectEngineCtx *, Signature *, const char *);
57 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
58  const DetectEngineTransforms *transforms,
59  Flow *f, const uint8_t flow_flags,
60  void *txv, const int list_id);
61 static int g_tls_sni_buffer_id = 0;
62 
63 /**
64  * \brief Registration function for keyword: tls.sni
65  */
67 {
68  sigmatch_table[DETECT_TLS_SNI].name = "tls.sni";
69  sigmatch_table[DETECT_TLS_SNI].alias = "tls_sni";
71  "sticky buffer to match specifically and only on the TLS SNI buffer";
72  sigmatch_table[DETECT_TLS_SNI].url = "/rules/tls-keywords.html#tls-sni";
73  sigmatch_table[DETECT_TLS_SNI].Setup = DetectTlsSniSetup;
76 
79 
82 
84  "TLS Server Name Indication (SNI) extension");
85 
86  g_tls_sni_buffer_id = DetectBufferTypeGetByName("tls.sni");
87 }
88 
89 
90 /**
91  * \brief this function setup the tls.sni modifier keyword used in the rule
92  *
93  * \param de_ctx Pointer to the Detection Engine Context
94  * \param s Pointer to the Signature to which the current keyword belongs
95  * \param str Should hold an empty string always
96  *
97  * \retval 0 On success
98  * \retval -1 On failure
99  */
100 static int DetectTlsSniSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
101 {
102  if (SCDetectBufferSetActiveList(de_ctx, s, g_tls_sni_buffer_id) < 0)
103  return -1;
104 
106  return -1;
107 
108  return 0;
109 }
110 
111 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
112  const DetectEngineTransforms *transforms, Flow *f,
113  const uint8_t flow_flags, void *txv, const int list_id)
114 {
115  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
116  if (buffer->inspect == NULL) {
117  const SSLState *ssl_state = (SSLState *)f->alstate;
118 
119  if (ssl_state->client_connp.sni == NULL) {
120  return NULL;
121  }
122 
123  const uint32_t data_len = (uint32_t)strlen(ssl_state->client_connp.sni);
124  const uint8_t *data = (uint8_t *)ssl_state->client_connp.sni;
125 
127  det_ctx, list_id, buffer, data, data_len, transforms);
128  }
129 
130  return buffer;
131 }
SigTableElmt_::url
const char * url
Definition: detect.h:1431
DetectSignatureSetAppProto
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
Definition: detect-parse.c:2313
SSLState_
SSLv[2.0|3.[0|1|2|3]] state structure.
Definition: app-layer-ssl.h:301
detect-content.h
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
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:2103
flow-util.h
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
stream-tcp.h
DetectEngineTransforms
Definition: detect.h:415
SSLState_::client_connp
SSLStateConnp client_connp
Definition: app-layer-ssl.h:322
ALPROTO_TLS
@ ALPROTO_TLS
Definition: app-layer-protos.h:39
InspectionBuffer
Definition: detect.h:380
threads.h
Flow_
Flow data structure.
Definition: flow.h:356
SigTableElmt_::flags
uint16_t flags
Definition: detect.h:1422
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:931
SSLStateConnp_::sni
char * sni
Definition: app-layer-ssl.h:270
SCDetectBufferSetActiveList
int SCDetectBufferSetActiveList(DetectEngineCtx *de_ctx, Signature *s, const int list)
Definition: detect-engine-buffer.c:29
detect-tls-sni.h
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1413
detect-pcre.h
detect-engine-prefilter.h
util-unittest.h
InspectionBufferGet
InspectionBuffer * InspectionBufferGet(DetectEngineThreadCtx *det_ctx, const int list_id)
Definition: detect-engine.c:1429
DetectTlsSniRegister
void DetectTlsSniRegister(void)
Registration function for keyword: tls.sni.
Definition: detect-tls-sni.c:66
util-unittest-helper.h
DetectBufferTypeGetByName
int DetectBufferTypeGetByName(const char *name)
Definition: detect-engine.c:1157
SIG_FLAG_TOSERVER
#define SIG_FLAG_TOSERVER
Definition: detect.h:270
decode.h
util-debug.h
de_ctx
DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:18
DetectEngineThreadCtx_
Definition: detect.h:1223
TLS_STATE_CLIENT_HELLO_DONE
@ TLS_STATE_CLIENT_HELLO_DONE
Definition: app-layer-ssl.h:79
util-print.h
detect-engine-mpm.h
detect.h
PrefilterGenericMpmRegister
int PrefilterGenericMpmRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, const DetectBufferMpmRegistry *mpm_reg, int list_id)
Definition: detect-engine-prefilter.c:1547
DetectAppLayerMpmRegister
void DetectAppLayerMpmRegister(const char *name, int direction, int priority, PrefilterRegisterFunc PrefilterRegister, InspectionBufferGetDataPtr GetData, AppProto alproto, int tx_min_progress)
register an app layer keyword for mpm
Definition: detect-engine-mpm.c:151
SigTableElmt_::alias
const char * alias
Definition: detect.h:1429
suricata-common.h
DETECT_TLS_SNI
@ DETECT_TLS_SNI
Definition: detect-engine-register.h:247
util-spm.h
detect-engine-buffer.h
InspectionBuffer::inspect
const uint8_t * inspect
Definition: detect.h:381
str
#define str(s)
Definition: suricata-common.h:308
Flow_::alstate
void * alstate
Definition: flow.h:479
detect-parse.h
Signature_
Signature container.
Definition: detect.h:670
SIGMATCH_NOOPT
#define SIGMATCH_NOOPT
Definition: detect.h:1620
DetectAppLayerInspectEngineRegister
void DetectAppLayerInspectEngineRegister(const char *name, AppProto alproto, uint32_t dir, int progress, InspectEngineFuncPtr Callback, InspectionBufferGetDataPtr GetData)
Registers an app inspection engine.
Definition: detect-engine.c:245
DetectBufferTypeSetDescriptionByName
void DetectBufferTypeSetDescriptionByName(const char *name, const char *desc)
Definition: detect-engine.c:1254
flow.h
flow-var.h
app-layer-ssl.h
app-layer.h