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 "debug.h"
29 #include "decode.h"
30 #include "detect.h"
31 
32 #include "detect-parse.h"
33 #include "detect-engine.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-unittest.h"
44 #include "util-spm.h"
45 #include "util-print.h"
46 
47 #include "stream-tcp.h"
48 
49 #include "app-layer.h"
50 #include "app-layer-ssl.h"
52 #include "detect-tls-sni.h"
53 
54 #include "util-unittest.h"
55 #include "util-unittest-helper.h"
56 
57 static int DetectTlsSniSetup(DetectEngineCtx *, Signature *, const char *);
58 #ifdef UNITTESTS
59 static void DetectTlsSniRegisterTests(void);
60 #endif
61 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
62  const DetectEngineTransforms *transforms,
63  Flow *f, const uint8_t flow_flags,
64  void *txv, const int list_id);
65 static int g_tls_sni_buffer_id = 0;
66 
67 /**
68  * \brief Registration function for keyword: tls.sni
69  */
71 {
74  sigmatch_table[DETECT_AL_TLS_SNI].desc = "content modifier to match specifically and only on the TLS SNI buffer";
75  sigmatch_table[DETECT_AL_TLS_SNI].url = DOC_URL DOC_VERSION "/rules/tls-keywords.html#tls-sni";
76  sigmatch_table[DETECT_AL_TLS_SNI].Setup = DetectTlsSniSetup;
77 #ifdef UNITTESTS
78  sigmatch_table[DETECT_AL_TLS_SNI].RegisterTests = DetectTlsSniRegisterTests;
79 #endif
82 
85 
88 
90  "TLS Server Name Indication (SNI) extension");
91 
92  g_tls_sni_buffer_id = DetectBufferTypeGetByName("tls.sni");
93 }
94 
95 
96 /**
97  * \brief this function setup the tls.sni modifier keyword used in the rule
98  *
99  * \param de_ctx Pointer to the Detection Engine Context
100  * \param s Pointer to the Signature to which the current keyword belongs
101  * \param str Should hold an empty string always
102  *
103  * \retval 0 On success
104  * \retval -1 On failure
105  */
106 static int DetectTlsSniSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
107 {
108  if (DetectBufferSetActiveList(s, g_tls_sni_buffer_id) < 0)
109  return -1;
110 
112  return -1;
113 
114  return 0;
115 }
116 
117 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
118  const DetectEngineTransforms *transforms, Flow *f,
119  const uint8_t flow_flags, void *txv, const int list_id)
120 {
121  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
122  if (buffer->inspect == NULL) {
123  const SSLState *ssl_state = (SSLState *)f->alstate;
124 
125  if (ssl_state->client_connp.sni == NULL) {
126  return NULL;
127  }
128 
129  const uint32_t data_len = strlen(ssl_state->client_connp.sni);
130  const uint8_t *data = (uint8_t *)ssl_state->client_connp.sni;
131 
132  InspectionBufferSetup(buffer, data, data_len);
133  InspectionBufferApplyTransforms(buffer, transforms);
134  }
135 
136  return buffer;
137 }
138 
139 #ifdef UNITTESTS
140 #include "tests/detect-tls-sni.c"
141 #endif
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect.h:1448
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1186
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
InspectionBuffer * InspectionBufferGet(DetectEngineThreadCtx *det_ctx, const int list_id)
const char * name
Definition: detect.h:1200
Signature container.
Definition: detect.h:522
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
main detection engine ctx
Definition: detect.h:761
SSLv[2.0|3.[0|1|2|3]] state structure.
void * alstate
Definition: flow.h:438
int DetectBufferTypeGetByName(const char *name)
#define str(s)
#define SIGMATCH_INFO_STICKY_BUFFER
Definition: detect.h:1393
#define SIG_FLAG_TOSERVER
Definition: detect.h:236
void DetectAppLayerInspectEngineRegister2(const char *name, AppProto alproto, uint32_t dir, int progress, InspectEngineFuncPtr2 Callback2, InspectionBufferGetDataPtr GetData)
register inspect engine at start up time
int 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.
const char * desc
Definition: detect.h:1202
int PrefilterGenericMpmRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, const DetectBufferMpmRegistery *mpm_reg, int list_id)
void DetectTlsSniRegister(void)
Registration function for keyword: tls.sni.
const char * alias
Definition: detect.h:1201
void InspectionBufferSetup(InspectionBuffer *buffer, const uint8_t *data, const uint32_t data_len)
setup the buffer with our initial data
void InspectionBufferApplyTransforms(InspectionBuffer *buffer, const DetectEngineTransforms *transforms)
#define SIGMATCH_NOOPT
Definition: detect.h:1369
const char * url
Definition: detect.h:1203
int DetectBufferSetActiveList(Signature *s, const int list)
const uint8_t * inspect
Definition: detect.h:343
#define DOC_URL
Definition: suricata.h:86
void DetectBufferTypeSetDescriptionByName(const char *name, const char *desc)
#define DOC_VERSION
Definition: suricata.h:91
uint16_t flags
Definition: detect.h:1194
Flow data structure.
Definition: flow.h:325
SSLStateConnp client_connp
void(* RegisterTests)(void)
Definition: detect.h:1192