suricata
detect-tls-cert-subject.c
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1 /* Copyright (C) 2007-2022 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 tls.cert_subject 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"
38 
39 #include "flow.h"
40 #include "flow-util.h"
41 #include "flow-var.h"
42 
43 #include "util-debug.h"
44 #include "util-spm.h"
45 #include "util-print.h"
46 
47 #include "stream-tcp.h"
48 
49 #include "app-layer.h"
50 #include "app-layer-ssl.h"
51 
52 #include "util-unittest.h"
53 #include "util-unittest-helper.h"
54 
55 static int DetectTlsSubjectSetup(DetectEngineCtx *, Signature *, const char *);
56 #ifdef UNITTESTS
57 static void DetectTlsSubjectRegisterTests(void);
58 #endif
59 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
60  const DetectEngineTransforms *transforms,
61  Flow *f, const uint8_t flow_flags,
62  void *txv, const int list_id);
63 static int g_tls_cert_subject_buffer_id = 0;
64 
65 /**
66  * \brief Registration function for keyword: tls.cert_subject
67  */
69 {
70  sigmatch_table[DETECT_AL_TLS_CERT_SUBJECT].name = "tls.cert_subject";
71  sigmatch_table[DETECT_AL_TLS_CERT_SUBJECT].alias = "tls_cert_subject";
73  "sticky buffer to match specifically and only on the TLS cert subject buffer";
74  sigmatch_table[DETECT_AL_TLS_CERT_SUBJECT].url = "/rules/tls-keywords.html#tls-cert-subject";
75  sigmatch_table[DETECT_AL_TLS_CERT_SUBJECT].Setup = DetectTlsSubjectSetup;
76 #ifdef UNITTESTS
77  sigmatch_table[DETECT_AL_TLS_CERT_SUBJECT].RegisterTests = DetectTlsSubjectRegisterTests;
78 #endif
81 
84 
87 
90 
93 
94  DetectBufferTypeSupportsMultiInstance("tls.cert_subject");
95 
96  DetectBufferTypeSetDescriptionByName("tls.cert_subject",
97  "TLS certificate subject");
98 
99  g_tls_cert_subject_buffer_id = DetectBufferTypeGetByName("tls.cert_subject");
100 }
101 
102 /**
103  * \brief this function setup the tls.cert_subject modifier keyword used in the rule
104  *
105  * \param de_ctx Pointer to the Detection Engine Context
106  * \param s Pointer to the Signature to which the current keyword belongs
107  * \param str Should hold an empty string always
108  *
109  * \retval 0 On success
110  * \retval -1 On failure
111  */
112 static int DetectTlsSubjectSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
113 {
114  if (DetectBufferSetActiveList(de_ctx, s, g_tls_cert_subject_buffer_id) < 0)
115  return -1;
116 
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  const SSLStateConnp *connp;
131 
132  if (flow_flags & STREAM_TOSERVER) {
133  connp = &ssl_state->client_connp;
134  } else {
135  connp = &ssl_state->server_connp;
136  }
137 
138  if (connp->cert0_subject == NULL) {
139  return NULL;
140  }
141 
142  const uint32_t data_len = strlen(connp->cert0_subject);
143  const uint8_t *data = (uint8_t *)connp->cert0_subject;
144 
145  InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);
146  InspectionBufferApplyTransforms(buffer, transforms);
147  }
148 
149  return buffer;
150 }
151 
152 #ifdef UNITTESTS
154 #endif
SigTableElmt_::url
const char * url
Definition: detect.h:1296
DetectSignatureSetAppProto
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
Definition: detect-parse.c:1753
SSLState_
SSLv[2.0|3.[0|1|2|3]] state structure.
Definition: app-layer-ssl.h:284
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
TLS_STATE_CERT_READY
@ TLS_STATE_CERT_READY
Definition: app-layer-ssl.h:78
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:2169
flow-util.h
SigTableElmt_::name
const char * name
Definition: detect.h:1293
stream-tcp.h
DetectEngineTransforms
Definition: detect.h:406
SSLState_::client_connp
SSLStateConnp client_connp
Definition: app-layer-ssl.h:302
ALPROTO_TLS
@ ALPROTO_TLS
Definition: app-layer-protos.h:33
SSLState_::server_connp
SSLStateConnp server_connp
Definition: app-layer-ssl.h:303
DetectBufferSetActiveList
int DetectBufferSetActiveList(DetectEngineCtx *de_ctx, Signature *s, const int list)
Definition: detect-engine.c:1382
SSLStateConnp_
Definition: app-layer-ssl.h:228
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
DetectBufferTypeSupportsMultiInstance
void DetectBufferTypeSupportsMultiInstance(const char *name)
Definition: detect-engine.c:1069
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:1526
util-unittest-helper.h
DetectBufferTypeGetByName
int DetectBufferTypeGetByName(const char *name)
Definition: detect-engine.c:1119
DETECT_AL_TLS_CERT_SUBJECT
@ DETECT_AL_TLS_CERT_SUBJECT
Definition: detect-engine-register.h:240
SIG_FLAG_TOSERVER
#define SIG_FLAG_TOSERVER
Definition: detect.h:263
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
SigTableElmt_::alias
const char * alias
Definition: detect.h:1294
suricata-common.h
InspectionBufferApplyTransforms
void InspectionBufferApplyTransforms(InspectionBuffer *buffer, const DetectEngineTransforms *transforms)
Definition: detect-engine.c:1725
sigmatch_table
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect-parse.c:127
util-spm.h
detect-tls-cert-subject.c
detect-tls-cert-subject.h
InspectionBuffer::inspect
const uint8_t * inspect
Definition: detect.h:372
str
#define str(s)
Definition: suricata-common.h:291
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:1621
Flow_::alstate
void * alstate
Definition: flow.h:476
detect-parse.h
Signature_
Signature container.
Definition: detect.h:593
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:216
DetectBufferTypeSetDescriptionByName
void DetectBufferTypeSetDescriptionByName(const char *name, const char *desc)
Definition: detect-engine.c:1216
flow.h
flow-var.h
DetectTlsSubjectRegister
void DetectTlsSubjectRegister(void)
Registration function for keyword: tls.cert_subject.
Definition: detect-tls-cert-subject.c:68
app-layer-ssl.h
SigTableElmt_::RegisterTests
void(* RegisterTests)(void)
Definition: detect.h:1285
app-layer.h