suricata
detect-tls-ja3-string.c
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1 /* Copyright (C) 2017 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 ja3.string 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"
36 #include "detect-content.h"
37 #include "detect-pcre.h"
38 #include "detect-tls-ja3-string.h"
39 
40 #include "flow.h"
41 #include "flow-util.h"
42 #include "flow-var.h"
43 
44 #include "conf.h"
45 #include "conf-yaml-loader.h"
46 
47 #include "util-debug.h"
48 #include "util-unittest.h"
49 #include "util-spm.h"
50 #include "util-print.h"
51 #include "util-ja3.h"
52 
53 #include "stream-tcp.h"
54 
55 #include "app-layer.h"
56 #include "app-layer-ssl.h"
57 
58 #include "util-unittest.h"
59 #include "util-unittest-helper.h"
60 
61 static int DetectTlsJa3StringSetup(DetectEngineCtx *, Signature *, const char *);
62 #ifdef UNITTESTS
63 static void DetectTlsJa3StringRegisterTests(void);
64 #endif
65 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
66  const DetectEngineTransforms *transforms,
67  Flow *f, const uint8_t flow_flags,
68  void *txv, const int list_id);
69 static int g_tls_ja3_str_buffer_id = 0;
70 
71 /**
72  * \brief Registration function for keyword: ja3.string
73  */
75 {
78  sigmatch_table[DETECT_AL_TLS_JA3_STRING].desc = "content modifier to match the JA3 string buffer";
79  sigmatch_table[DETECT_AL_TLS_JA3_STRING].url = DOC_URL DOC_VERSION "/rules/ja3-keywords.html#ja3-string";
80  sigmatch_table[DETECT_AL_TLS_JA3_STRING].Setup = DetectTlsJa3StringSetup;
81 #ifdef UNITTESTS
82  sigmatch_table[DETECT_AL_TLS_JA3_STRING].RegisterTests = DetectTlsJa3StringRegisterTests;
83 #endif
86 
89 
92 
93  DetectBufferTypeSetDescriptionByName("ja3.string", "TLS JA3 string");
94 
95  g_tls_ja3_str_buffer_id = DetectBufferTypeGetByName("ja3.string");
96 }
97 
98 /**
99  * \brief this function setup the ja3.string modifier keyword used in the rule
100  *
101  * \param de_ctx Pointer to the Detection Engine Context
102  * \param s Pointer to the Signature to which the current keyword belongs
103  * \param str Should hold an empty string always
104  *
105  * \retval 0 On success
106  * \retval -1 On failure
107  */
108 static int DetectTlsJa3StringSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
109 {
110  if (DetectBufferSetActiveList(s, g_tls_ja3_str_buffer_id) < 0)
111  return -1;
112 
114  return -1;
115 
116  /* Check if JA3 is disabled */
117  if (!RunmodeIsUnittests() && Ja3IsDisabled("rule"))
118  return -1;
119 
120  return 0;
121 }
122 
123 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
124  const DetectEngineTransforms *transforms, Flow *f,
125  const uint8_t flow_flags, void *txv, const int list_id)
126 {
127  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
128  if (buffer->inspect == NULL) {
129  const SSLState *ssl_state = (SSLState *)f->alstate;
130 
131  if (ssl_state->client_connp.ja3_str == NULL ||
132  ssl_state->client_connp.ja3_str->data == NULL) {
133  return NULL;
134  }
135 
136  const uint32_t data_len = strlen(ssl_state->client_connp.ja3_str->data);
137  const uint8_t *data = (uint8_t *)ssl_state->client_connp.ja3_str->data;
138 
139  InspectionBufferSetup(buffer, data, data_len);
140  InspectionBufferApplyTransforms(buffer, transforms);
141  }
142 
143  return buffer;
144 }
145 
146 #ifdef UNITTESTS
148 #endif
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect.h:1439
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1179
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
char * data
Definition: util-ja3.h:30
int Ja3IsDisabled(const char *type)
Check if JA3 is disabled.
Definition: util-ja3.c:262
InspectionBuffer * InspectionBufferGet(DetectEngineThreadCtx *det_ctx, const int list_id)
const char * name
Definition: detect.h:1193
Signature container.
Definition: detect.h:517
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:756
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:1386
#define SIG_FLAG_TOSERVER
Definition: detect.h:232
void DetectAppLayerInspectEngineRegister2(const char *name, AppProto alproto, uint32_t dir, int progress, InspectEngineFuncPtr2 Callback2, InspectionBufferGetDataPtr GetData)
register inspect engine at start up time
int RunmodeIsUnittests(void)
Definition: suricata.c:265
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:1195
int PrefilterGenericMpmRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, const DetectBufferMpmRegistery *mpm_reg, int list_id)
const char * alias
Definition: detect.h:1194
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)
void DetectTlsJa3StringRegister(void)
Registration function for keyword: ja3.string.
#define SIGMATCH_NOOPT
Definition: detect.h:1362
const char * url
Definition: detect.h:1196
int DetectBufferSetActiveList(Signature *s, const int list)
const uint8_t * inspect
Definition: detect.h:338
#define DOC_URL
Definition: suricata.h:86
void DetectBufferTypeSetDescriptionByName(const char *name, const char *desc)
JA3Buffer * ja3_str
#define DOC_VERSION
Definition: suricata.h:91
uint16_t flags
Definition: detect.h:1187
Flow data structure.
Definition: flow.h:325
SSLStateConnp client_connp
void(* RegisterTests)(void)
Definition: detect.h:1185