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-buffer.h"
34 #include "detect-engine-mpm.h"
36 #include "detect-content.h"
37 #include "detect-pcre.h"
38 #include "detect-tls-ja3s-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-spm.h"
49 #include "util-print.h"
50 #include "util-ja3.h"
51 
52 #include "stream-tcp.h"
53 
54 #include "app-layer.h"
55 #include "app-layer-ssl.h"
56 
57 #include "util-unittest.h"
58 #include "util-unittest-helper.h"
59 
60 #ifndef HAVE_JA3
61 static int DetectJA3SetupNoSupport(DetectEngineCtx *a, Signature *b, const char *c)
62 {
63  SCLogError("no JA3 support built in");
64  return -1;
65 }
66 #endif /* HAVE_JA3 */
67 
68 #ifdef HAVE_JA3
69 static int DetectTlsJa3SStringSetup(DetectEngineCtx *, Signature *, const char *);
70 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
71  const DetectEngineTransforms *transforms,
72  Flow *f, const uint8_t flow_flags,
73  void *txv, const int list_id);
74 static int g_tls_ja3s_str_buffer_id = 0;
75 #endif
76 
77 /**
78  * \brief Registration function for keyword: ja3s.string
79  */
81 {
83  sigmatch_table[DETECT_TLS_JA3S_STRING].desc = "sticky buffer to match the JA3S string buffer";
84  sigmatch_table[DETECT_TLS_JA3S_STRING].url = "/rules/ja3-keywords.html#ja3s-string";
85 #ifdef HAVE_JA3
86  sigmatch_table[DETECT_TLS_JA3S_STRING].Setup = DetectTlsJa3SStringSetup;
87 #else /* HAVE_JA3 */
88  sigmatch_table[DETECT_TLS_JA3S_STRING].Setup = DetectJA3SetupNoSupport;
89 #endif /* HAVE_JA3 */
92 
93 #ifdef HAVE_JA3
96 
99 
101  Ja3DetectGetString, ALPROTO_QUIC, 1);
102 
104  DetectEngineInspectBufferGeneric, Ja3DetectGetString);
105 
106  DetectBufferTypeSetDescriptionByName("ja3s.string", "TLS JA3S string");
107 
108  g_tls_ja3s_str_buffer_id = DetectBufferTypeGetByName("ja3s.string");
109 #endif /* HAVE_JA3 */
110 }
111 
112 #ifdef HAVE_JA3
113 /**
114  * \brief this function setup the ja3s.string modifier keyword used in the rule
115  *
116  * \param de_ctx Pointer to the Detection Engine Context
117  * \param s Pointer to the Signature to which the current keyword belongs
118  * \param str Should hold an empty string always
119  *
120  * \retval 0 On success
121  * \retval -1 On failure
122  */
123 static int DetectTlsJa3SStringSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
124 {
125  if (SCDetectBufferSetActiveList(de_ctx, s, g_tls_ja3s_str_buffer_id) < 0)
126  return -1;
127 
129  if (DetectSignatureSetMultiAppProto(s, alprotos) < 0) {
130  SCLogError("rule contains conflicting protocols.");
131  return -1;
132  }
133 
134  /* try to enable JA3 */
135  SSLEnableJA3();
136 
137  /* Check if JA3 is disabled */
138  if (!RunmodeIsUnittests() && Ja3IsDisabled("rule")) {
140  SCLogError("ja3(s) support is not enabled");
141  }
142  return -2;
143  }
144 
145  return 0;
146 }
147 
148 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
149  const DetectEngineTransforms *transforms, Flow *f,
150  const uint8_t flow_flags, void *txv, const int list_id)
151 {
152  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
153  if (buffer->inspect == NULL) {
154  const SSLState *ssl_state = (SSLState *)f->alstate;
155 
156  if (ssl_state->server_connp.ja3_str == NULL ||
157  ssl_state->server_connp.ja3_str->data == NULL) {
158  return NULL;
159  }
160 
161  const uint32_t data_len = (uint32_t)strlen(ssl_state->server_connp.ja3_str->data);
162  const uint8_t *data = (uint8_t *)ssl_state->server_connp.ja3_str->data;
163 
165  det_ctx, list_id, buffer, data, data_len, transforms);
166  }
167 
168  return buffer;
169 }
170 #endif
SigTableElmt_::url
const char * url
Definition: detect.h:1431
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
DetectSignatureSetMultiAppProto
int DetectSignatureSetMultiAppProto(Signature *s, const AppProto *alprotos)
this function is used to set multiple possible app-layer protos
Definition: detect-parse.c:2235
ALPROTO_TLS
@ ALPROTO_TLS
Definition: app-layer-protos.h:39
SSLState_::server_connp
SSLStateConnp server_connp
Definition: app-layer-ssl.h:323
AppProto
uint16_t AppProto
Definition: app-layer-protos.h:85
ALPROTO_QUIC
@ ALPROTO_QUIC
Definition: app-layer-protos.h:57
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
JA3Buffer_::data
char * data
Definition: util-ja3.h:32
util-ja3.h
SCDetectBufferSetActiveList
int SCDetectBufferSetActiveList(DetectEngineCtx *de_ctx, Signature *s, const int list)
Definition: detect-engine-buffer.c:29
SIG_FLAG_TOCLIENT
#define SIG_FLAG_TOCLIENT
Definition: detect.h:271
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
util-unittest-helper.h
DetectBufferTypeGetByName
int DetectBufferTypeGetByName(const char *name)
Definition: detect-engine.c:1157
Ja3IsDisabled
int Ja3IsDisabled(const char *type)
Definition: util-ja3.c:324
decode.h
util-debug.h
de_ctx
DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:18
DetectEngineThreadCtx_
Definition: detect.h:1223
DETECT_TLS_JA3S_STRING
@ DETECT_TLS_JA3S_STRING
Definition: detect-engine-register.h:261
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
conf-yaml-loader.h
conf.h
SSLEnableJA3
void SSLEnableJA3(void)
if not explicitly disabled in config, enable ja3 support
Definition: app-layer-ssl.c:3489
RunmodeIsUnittests
int RunmodeIsUnittests(void)
Definition: suricata.c:257
SigMatchSilentErrorEnabled
bool SigMatchSilentErrorEnabled(const DetectEngineCtx *de_ctx, const enum DetectKeywordId id)
Definition: detect-parse.c:406
suricata-common.h
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
SCLogError
#define SCLogError(...)
Macro used to log ERROR messages.
Definition: util-debug.h:261
Flow_::alstate
void * alstate
Definition: flow.h:479
detect-parse.h
Signature_
Signature container.
Definition: detect.h:670
DetectTlsJa3SStringRegister
void DetectTlsJa3SStringRegister(void)
Registration function for keyword: ja3s.string.
Definition: detect-tls-ja3s-string.c:80
ALPROTO_UNKNOWN
@ ALPROTO_UNKNOWN
Definition: app-layer-protos.h:29
detect-tls-ja3s-string.h
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
TLS_STATE_SERVER_HELLO
@ TLS_STATE_SERVER_HELLO
Definition: app-layer-ssl.h:87
DetectBufferTypeSetDescriptionByName
void DetectBufferTypeSetDescriptionByName(const char *name, const char *desc)
Definition: detect-engine.c:1254
flow.h
SSLStateConnp_::ja3_str
JA3Buffer * ja3_str
Definition: app-layer-ssl.h:282
flow-var.h
app-layer-ssl.h
app-layer.h