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-unittest.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 static int DetectTlsJa3SStringSetup(DetectEngineCtx *, Signature *, const char *);
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_ja3s_str_buffer_id = 0;
66 
67 static InspectionBuffer *GetJa3Data(DetectEngineThreadCtx *det_ctx,
68  const DetectEngineTransforms *transforms, Flow *_f, const uint8_t _flow_flags, void *txv,
69  const int list_id)
70 {
71  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
72  if (buffer->inspect == NULL) {
73  uint32_t b_len = 0;
74  const uint8_t *b = NULL;
75 
76  if (rs_quic_tx_get_ja3(txv, &b, &b_len) != 1)
77  return NULL;
78  if (b == NULL || b_len == 0)
79  return NULL;
80 
81  InspectionBufferSetup(det_ctx, list_id, buffer, b, b_len);
82  InspectionBufferApplyTransforms(buffer, transforms);
83  }
84  return buffer;
85 }
86 
87 /**
88  * \brief Registration function for keyword: ja3s.string
89  */
91 {
94  "sticky buffer to match the JA3S string buffer";
95  sigmatch_table[DETECT_AL_TLS_JA3S_STRING].url = "/rules/ja3-keywords.html#ja3s-string";
96  sigmatch_table[DETECT_AL_TLS_JA3S_STRING].Setup = DetectTlsJa3SStringSetup;
99 
102 
105 
107  GetJa3Data, ALPROTO_QUIC, 1);
108 
111 
112  DetectBufferTypeSetDescriptionByName("ja3s.string", "TLS JA3S string");
113 
114  g_tls_ja3s_str_buffer_id = DetectBufferTypeGetByName("ja3s.string");
115 }
116 
117 /**
118  * \brief this function setup the ja3s.string modifier keyword used in the rule
119  *
120  * \param de_ctx Pointer to the Detection Engine Context
121  * \param s Pointer to the Signature to which the current keyword belongs
122  * \param str Should hold an empty string always
123  *
124  * \retval 0 On success
125  * \retval -1 On failure
126  */
127 static int DetectTlsJa3SStringSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
128 {
129  if (DetectBufferSetActiveList(s, g_tls_ja3s_str_buffer_id) < 0)
130  return -1;
131 
132  if (s->alproto != ALPROTO_UNKNOWN && s->alproto != ALPROTO_TLS && s->alproto != ALPROTO_QUIC) {
133  SCLogError(SC_ERR_CONFLICTING_RULE_KEYWORDS, "rule contains conflicting protocols.");
134  return -1;
135  }
136 
137  /* try to enable JA3 */
138  SSLEnableJA3();
139 
140  /* Check if JA3 is disabled */
141  if (!RunmodeIsUnittests() && Ja3IsDisabled("rule")) {
143  SCLogError(SC_WARN_JA3_DISABLED, "ja3(s) support is not enabled");
144  }
145  return -2;
146  }
147 
148  return 0;
149 }
150 
151 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
152  const DetectEngineTransforms *transforms, Flow *f,
153  const uint8_t flow_flags, void *txv, const int list_id)
154 {
155  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
156  if (buffer->inspect == NULL) {
157  const SSLState *ssl_state = (SSLState *)f->alstate;
158 
159  if (ssl_state->server_connp.ja3_str == NULL ||
160  ssl_state->server_connp.ja3_str->data == NULL) {
161  return NULL;
162  }
163 
164  const uint32_t data_len = strlen(ssl_state->server_connp.ja3_str->data);
165  const uint8_t *data = (uint8_t *)ssl_state->server_connp.ja3_str->data;
166 
167  InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);
168  InspectionBufferApplyTransforms(buffer, transforms);
169  }
170 
171  return buffer;
172 }
SigTableElmt_::url
const char * url
Definition: detect.h:1248
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:1455
SigTableElmt_::desc
const char * desc
Definition: detect.h:1247
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:1994
flow-util.h
SigTableElmt_::name
const char * name
Definition: detect.h:1245
stream-tcp.h
DetectEngineTransforms
Definition: detect.h:372
ALPROTO_TLS
@ ALPROTO_TLS
Definition: app-layer-protos.h:33
Signature_::alproto
AppProto alproto
Definition: detect.h:544
SSLState_::server_connp
SSLStateConnp server_connp
Definition: app-layer-ssl.h:306
ALPROTO_QUIC
@ ALPROTO_QUIC
Definition: app-layer-protos.h:51
InspectionBuffer
Definition: detect.h:338
threads.h
Flow_
Flow data structure.
Definition: flow.h:353
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:755
SigTableElmt_::flags
uint16_t flags
Definition: detect.h:1239
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:785
JA3Buffer_::data
char * data
Definition: util-ja3.h:30
util-ja3.h
SIG_FLAG_TOCLIENT
#define SIG_FLAG_TOCLIENT
Definition: detect.h:231
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1230
detect-pcre.h
detect-engine-prefilter.h
util-unittest.h
InspectionBufferGet
InspectionBuffer * InspectionBufferGet(DetectEngineThreadCtx *det_ctx, const int list_id)
Definition: detect-engine.c:1369
util-unittest-helper.h
DetectBufferTypeGetByName
int DetectBufferTypeGetByName(const char *name)
Definition: detect-engine.c:1086
Ja3IsDisabled
int Ja3IsDisabled(const char *type)
Check if JA3 is disabled.
Definition: util-ja3.c:249
decode.h
util-debug.h
de_ctx
DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:17
DetectEngineThreadCtx_
Definition: detect.h:1034
util-print.h
detect-engine-mpm.h
detect.h
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:3084
RunmodeIsUnittests
int RunmodeIsUnittests(void)
Definition: suricata.c:279
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:292
suricata-common.h
InspectionBufferApplyTransforms
void InspectionBufferApplyTransforms(InspectionBuffer *buffer, const DetectEngineTransforms *transforms)
Definition: detect-engine.c:1552
sigmatch_table
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect-parse.c:73
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:339
str
#define str(s)
Definition: suricata-common.h:272
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:1450
Flow_::alstate
void * alstate
Definition: flow.h:486
detect-parse.h
Signature_
Signature container.
Definition: detect.h:540
DetectTlsJa3SStringRegister
void DetectTlsJa3SStringRegister(void)
Registration function for keyword: ja3s.string.
Definition: detect-tls-ja3s-string.c:90
ALPROTO_UNKNOWN
@ ALPROTO_UNKNOWN
Definition: app-layer-protos.h:29
detect-tls-ja3s-string.h
SIGMATCH_NOOPT
#define SIGMATCH_NOOPT
Definition: detect.h:1431
DetectBufferSetActiveList
int DetectBufferSetActiveList(Signature *s, const int list)
Definition: detect-engine.c:1300
DetectBufferTypeSetDescriptionByName
void DetectBufferTypeSetDescriptionByName(const char *name, const char *desc)
Definition: detect-engine.c:1183
flow.h
SSLStateConnp_::ja3_str
JA3Buffer * ja3_str
Definition: app-layer-ssl.h:271
DETECT_AL_TLS_JA3S_STRING
@ DETECT_AL_TLS_JA3S_STRING
Definition: detect-engine-register.h:234
flow-var.h
app-layer-ssl.h
app-layer.h
SC_ERR_CONFLICTING_RULE_KEYWORDS
@ SC_ERR_CONFLICTING_RULE_KEYWORDS
Definition: util-error.h:171