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 "decode.h"
29 #include "detect.h"
30 
31 #include "detect-parse.h"
32 #include "detect-engine.h"
33 #include "detect-engine-mpm.h"
35 #include "detect-content.h"
36 #include "detect-pcre.h"
37 #include "detect-tls-ja3-string.h"
38 
39 #include "flow.h"
40 #include "flow-util.h"
41 #include "flow-var.h"
42 
43 #include "conf.h"
44 #include "conf-yaml-loader.h"
45 
46 #include "util-debug.h"
47 #include "util-spm.h"
48 #include "util-print.h"
49 #include "util-ja3.h"
50 
51 #include "stream-tcp.h"
52 
53 #include "app-layer.h"
54 #include "app-layer-ssl.h"
55 
56 #include "util-unittest.h"
57 #include "util-unittest-helper.h"
58 
59 static int DetectTlsJa3StringSetup(DetectEngineCtx *, Signature *, const char *);
60 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
61  const DetectEngineTransforms *transforms,
62  Flow *f, const uint8_t flow_flags,
63  void *txv, const int list_id);
64 static int g_tls_ja3_str_buffer_id = 0;
65 
66 /**
67  * \brief Registration function for keyword: ja3.string
68  */
70 {
73  sigmatch_table[DETECT_AL_TLS_JA3_STRING].desc = "sticky buffer to match the JA3 string buffer";
74  sigmatch_table[DETECT_AL_TLS_JA3_STRING].url = "/rules/ja3-keywords.html#ja3-string";
75  sigmatch_table[DETECT_AL_TLS_JA3_STRING].Setup = DetectTlsJa3StringSetup;
78 
81 
84 
87 
90 
91  DetectBufferTypeSetDescriptionByName("ja3.string", "TLS JA3 string");
92 
93  g_tls_ja3_str_buffer_id = DetectBufferTypeGetByName("ja3.string");
94 }
95 
96 /**
97  * \brief this function setup the ja3.string 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 DetectTlsJa3StringSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
107 {
108  if (DetectBufferSetActiveList(s, g_tls_ja3_str_buffer_id) < 0)
109  return -1;
110 
111  if (s->alproto != ALPROTO_UNKNOWN && s->alproto != ALPROTO_TLS && s->alproto != ALPROTO_QUIC) {
112  SCLogError(SC_ERR_CONFLICTING_RULE_KEYWORDS, "rule contains conflicting protocols.");
113  return -1;
114  }
115 
116  /* try to enable JA3 */
117  SSLEnableJA3();
118 
119  /* Check if JA3 is disabled */
120  if (!RunmodeIsUnittests() && Ja3IsDisabled("rule")) {
122  SCLogError(SC_WARN_JA3_DISABLED, "ja3(s) support is not enabled");
123  }
124  return -2;
125  }
127 
128  return 0;
129 }
130 
131 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
132  const DetectEngineTransforms *transforms, Flow *f,
133  const uint8_t flow_flags, void *txv, const int list_id)
134 {
135  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
136  if (buffer->inspect == NULL) {
137  const SSLState *ssl_state = (SSLState *)f->alstate;
138 
139  if (ssl_state->client_connp.ja3_str == NULL ||
140  ssl_state->client_connp.ja3_str->data == NULL) {
141  return NULL;
142  }
143 
144  const uint32_t data_len = strlen(ssl_state->client_connp.ja3_str->data);
145  const uint8_t *data = (uint8_t *)ssl_state->client_connp.ja3_str->data;
146 
147  InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);
148  InspectionBufferApplyTransforms(buffer, transforms);
149  }
150 
151  return buffer;
152 }
SigTableElmt_::url
const char * url
Definition: detect.h:1238
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:1444
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:1993
flow-util.h
SIG_FLAG_INIT_JA3
#define SIG_FLAG_INIT_JA3
Definition: detect.h:258
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
Signature_::alproto
AppProto alproto
Definition: detect.h:543
ALPROTO_QUIC
@ ALPROTO_QUIC
Definition: app-layer-protos.h:51
DetectTlsJa3StringRegister
void DetectTlsJa3StringRegister(void)
Registration function for keyword: ja3.string.
Definition: detect-tls-ja3-string.c:69
InspectionBuffer
Definition: detect.h:337
threads.h
Flow_
Flow data structure.
Definition: flow.h:356
SC_WARN_JA3_DISABLED
@ SC_WARN_JA3_DISABLED
Definition: util-error.h:342
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
detect-tls-ja3-string.h
JA3Buffer_::data
char * data
Definition: util-ja3.h:32
util-ja3.h
SignatureInitData_::init_flags
uint32_t init_flags
Definition: detect.h:502
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:1368
util-unittest-helper.h
DetectBufferTypeGetByName
int DetectBufferTypeGetByName(const char *name)
Definition: detect-engine.c:1085
Ja3IsDisabled
int Ja3IsDisabled(const char *type)
Check if JA3 is disabled.
Definition: util-ja3.c:248
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
DETECT_AL_TLS_JA3_STRING
@ DETECT_AL_TLS_JA3_STRING
Definition: detect-engine-register.h:236
conf-yaml-loader.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:227
conf.h
SSLEnableJA3
void SSLEnableJA3(void)
if not explicitly disabled in config, enable ja3 support
Definition: app-layer-ssl.c:3094
Signature_::init_data
SignatureInitData * init_data
Definition: detect.h:610
RunmodeIsUnittests
int RunmodeIsUnittests(void)
Definition: suricata.c:234
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
SigMatchSilentErrorEnabled
bool SigMatchSilentErrorEnabled(const DetectEngineCtx *de_ctx, const enum DetectKeywordId id)
Definition: detect-parse.c:295
SigTableElmt_::alias
const char * alias
Definition: detect.h:1236
suricata-common.h
InspectionBufferApplyTransforms
void InspectionBufferApplyTransforms(InspectionBuffer *buffer, const DetectEngineTransforms *transforms)
Definition: detect-engine.c:1551
sigmatch_table
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect-parse.c:76
util-spm.h
SCLogError
#define SCLogError(err_code,...)
Macro used to log ERROR messages.
Definition: util-debug.h:255
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:1449
Flow_::alstate
void * alstate
Definition: flow.h:489
detect-parse.h
Signature_
Signature container.
Definition: detect.h:539
ALPROTO_UNKNOWN
@ ALPROTO_UNKNOWN
Definition: app-layer-protos.h:29
SIGMATCH_NOOPT
#define SIGMATCH_NOOPT
Definition: detect.h:1420
DetectBufferSetActiveList
int DetectBufferSetActiveList(Signature *s, const int list)
Definition: detect-engine.c:1299
DetectBufferTypeSetDescriptionByName
void DetectBufferTypeSetDescriptionByName(const char *name, const char *desc)
Definition: detect-engine.c:1182
flow.h
SSLStateConnp_::ja3_str
JA3Buffer * ja3_str
Definition: app-layer-ssl.h:271
flow-var.h
app-layer-ssl.h
app-layer.h
Ja3DetectGetString
InspectionBuffer * Ja3DetectGetString(DetectEngineThreadCtx *det_ctx, const DetectEngineTransforms *transforms, Flow *_f, const uint8_t _flow_flags, void *txv, const int list_id)
Definition: util-ja3.c:287
SC_ERR_CONFLICTING_RULE_KEYWORDS
@ SC_ERR_CONFLICTING_RULE_KEYWORDS
Definition: util-error.h:171