suricata
detect-tls-ja3s-string.c
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1 /* Copyright (C) 2019 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 ja3s.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-ja3s-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 #ifndef HAVE_JA3
60 static int DetectJA3SetupNoSupport(DetectEngineCtx *a, Signature *b, const char *c)
61 {
62  SCLogError("no JA3 support built in");
63  return -1;
64 }
65 #endif /* HAVE_JA3 */
66 
67 static int DetectTlsJa3SStringSetup(DetectEngineCtx *, Signature *, const char *);
68 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
69  const DetectEngineTransforms *transforms,
70  Flow *f, const uint8_t flow_flags,
71  void *txv, const int list_id);
72 static int g_tls_ja3s_str_buffer_id = 0;
73 
74 /**
75  * \brief Registration function for keyword: ja3s.string
76  */
78 {
81  "sticky buffer to match the JA3S string buffer";
82  sigmatch_table[DETECT_AL_TLS_JA3S_STRING].url = "/rules/ja3-keywords.html#ja3s-string";
83 #ifdef HAVE_JA3
84  sigmatch_table[DETECT_AL_TLS_JA3S_STRING].Setup = DetectTlsJa3SStringSetup;
85 #else /* HAVE_JA3 */
86  sigmatch_table[DETECT_AL_TLS_JA3S_STRING].Setup = DetectJA3SetupNoSupport;
87 #endif /* HAVE_JA3 */
90 
91 #ifdef HAVE_JA3
94 
96  GetData, ALPROTO_TLS, 0);
97 
99  Ja3DetectGetString, ALPROTO_QUIC, 1);
100 
102  DetectEngineInspectBufferGeneric, Ja3DetectGetString);
103 
104  DetectBufferTypeSetDescriptionByName("ja3s.string", "TLS JA3S string");
105 
106  g_tls_ja3s_str_buffer_id = DetectBufferTypeGetByName("ja3s.string");
107 #endif /* HAVE_JA3 */
108 }
109 
110 /**
111  * \brief this function setup the ja3s.string modifier keyword used in the rule
112  *
113  * \param de_ctx Pointer to the Detection Engine Context
114  * \param s Pointer to the Signature to which the current keyword belongs
115  * \param str Should hold an empty string always
116  *
117  * \retval 0 On success
118  * \retval -1 On failure
119  */
120 static int DetectTlsJa3SStringSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
121 {
122  if (DetectBufferSetActiveList(de_ctx, s, g_tls_ja3s_str_buffer_id) < 0)
123  return -1;
124 
125  if (s->alproto != ALPROTO_UNKNOWN && s->alproto != ALPROTO_TLS && s->alproto != ALPROTO_QUIC) {
126  SCLogError("rule contains conflicting protocols.");
127  return -1;
128  }
129 
130  /* try to enable JA3 */
131  SSLEnableJA3();
132 
133  /* Check if JA3 is disabled */
134  if (!RunmodeIsUnittests() && Ja3IsDisabled("rule")) {
136  SCLogError("ja3(s) support is not enabled");
137  }
138  return -2;
139  }
141 
142  return 0;
143 }
144 
145 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
146  const DetectEngineTransforms *transforms, Flow *f,
147  const uint8_t flow_flags, void *txv, const int list_id)
148 {
149  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
150  if (buffer->inspect == NULL) {
151  const SSLState *ssl_state = (SSLState *)f->alstate;
152 
153  if (ssl_state->server_connp.ja3_str == NULL ||
154  ssl_state->server_connp.ja3_str->data == NULL) {
155  return NULL;
156  }
157 
158  const uint32_t data_len = strlen(ssl_state->server_connp.ja3_str->data);
159  const uint8_t *data = (uint8_t *)ssl_state->server_connp.ja3_str->data;
160 
161  InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);
162  InspectionBufferApplyTransforms(buffer, transforms);
163  }
164 
165  return buffer;
166 }
SigTableElmt_::url
const char * url
Definition: detect.h:1296
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:1497
SigTableElmt_::desc
const char * desc
Definition: detect.h:1295
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:2122
flow-util.h
SigTableElmt_::name
const char * name
Definition: detect.h:1293
stream-tcp.h
DetectEngineTransforms
Definition: detect.h:406
ALPROTO_TLS
@ ALPROTO_TLS
Definition: app-layer-protos.h:33
Signature_::alproto
AppProto alproto
Definition: detect.h:598
SSLState_::server_connp
SSLStateConnp server_connp
Definition: app-layer-ssl.h:307
ALPROTO_QUIC
@ ALPROTO_QUIC
Definition: app-layer-protos.h:51
DetectBufferSetActiveList
int DetectBufferSetActiveList(DetectEngineCtx *de_ctx, Signature *s, const int list)
Definition: detect-engine.c:1335
InspectionBuffer
Definition: detect.h:371
threads.h
Flow_
Flow data structure.
Definition: flow.h:351
SigTableElmt_::flags
uint16_t flags
Definition: detect.h:1287
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:836
JA3Buffer_::data
char * data
Definition: util-ja3.h:32
util-ja3.h
SignatureInitData_::init_flags
uint32_t init_flags
Definition: detect.h:545
SIG_FLAG_TOCLIENT
#define SIG_FLAG_TOCLIENT
Definition: detect.h:264
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1278
detect-pcre.h
detect-engine-prefilter.h
util-unittest.h
InspectionBufferGet
InspectionBuffer * InspectionBufferGet(DetectEngineThreadCtx *det_ctx, const int list_id)
Definition: detect-engine.c:1479
util-unittest-helper.h
DetectBufferTypeGetByName
int DetectBufferTypeGetByName(const char *name)
Definition: detect-engine.c:1072
Ja3IsDisabled
int Ja3IsDisabled(const char *type)
Definition: util-ja3.c:325
decode.h
util-debug.h
de_ctx
DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:17
DetectEngineThreadCtx_
Definition: detect.h:1092
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:745
DetectAppLayerMpmRegister
void DetectAppLayerMpmRegister(const char *name, int direction, int priority, PrefilterRegisterFunc PrefilterRegister, InspectionBufferGetDataPtr GetData, AppProto alproto, int tx_min_progress)
register a MPM engine
Definition: detect-engine-mpm.c:89
conf-yaml-loader.h
conf.h
SSLEnableJA3
void SSLEnableJA3(void)
if not explicitly disabled in config, enable ja3 support
Definition: app-layer-ssl.c:3315
Signature_::init_data
SignatureInitData * init_data
Definition: detect.h:662
RunmodeIsUnittests
int RunmodeIsUnittests(void)
Definition: suricata.c:257
SIG_FLAG_INIT_JA
#define SIG_FLAG_INIT_JA
Definition: detect.h:293
SigMatchSilentErrorEnabled
bool SigMatchSilentErrorEnabled(const DetectEngineCtx *de_ctx, const enum DetectKeywordId id)
Definition: detect-parse.c:389
suricata-common.h
InspectionBufferApplyTransforms
void InspectionBufferApplyTransforms(InspectionBuffer *buffer, const DetectEngineTransforms *transforms)
Definition: detect-engine.c:1678
sigmatch_table
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect-parse.c:127
util-spm.h
InspectionBuffer::inspect
const uint8_t * inspect
Definition: detect.h:372
str
#define str(s)
Definition: suricata-common.h:291
SCLogError
#define SCLogError(...)
Macro used to log ERROR messages.
Definition: util-debug.h:261
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:1574
Flow_::alstate
void * alstate
Definition: flow.h:476
detect-parse.h
Signature_
Signature container.
Definition: detect.h:593
DetectTlsJa3SStringRegister
void DetectTlsJa3SStringRegister(void)
Registration function for keyword: ja3s.string.
Definition: detect-tls-ja3s-string.c:77
ALPROTO_UNKNOWN
@ ALPROTO_UNKNOWN
Definition: app-layer-protos.h:29
detect-tls-ja3s-string.h
SIGMATCH_NOOPT
#define SIGMATCH_NOOPT
Definition: detect.h:1473
DetectAppLayerInspectEngineRegister
void DetectAppLayerInspectEngineRegister(const char *name, AppProto alproto, uint32_t dir, int progress, InspectEngineFuncPtr Callback, InspectionBufferGetDataPtr GetData)
register inspect engine at start up time
Definition: detect-engine.c:169
DetectBufferTypeSetDescriptionByName
void DetectBufferTypeSetDescriptionByName(const char *name, const char *desc)
Definition: detect-engine.c:1169
flow.h
SSLStateConnp_::ja3_str
JA3Buffer * ja3_str
Definition: app-layer-ssl.h:269
DETECT_AL_TLS_JA3S_STRING
@ DETECT_AL_TLS_JA3S_STRING
Definition: detect-engine-register.h:250
flow-var.h
app-layer-ssl.h
app-layer.h