suricata
detect-tls-cert-issuer.c
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1 /* Copyright (C) 2007-2016 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_issuer keyword.
24  */
25 
26 #include "suricata-common.h"
27 #include "threads.h"
28 #include "debug.h"
29 #include "decode.h"
30 #include "detect.h"
31 
32 #include "detect-parse.h"
33 #include "detect-engine.h"
34 #include "detect-engine-mpm.h"
36 #include "detect-content.h"
37 #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-unittest.h"
45 #include "util-spm.h"
46 #include "util-print.h"
47 
48 #include "stream-tcp.h"
49 
50 #include "app-layer.h"
51 #include "app-layer-ssl.h"
52 #include "detect-tls-cert-issuer.h"
53 
54 #include "util-unittest.h"
55 #include "util-unittest-helper.h"
56 
57 static int DetectTlsIssuerSetup(DetectEngineCtx *, Signature *, const char *);
58 #ifdef UNITTESTS
59 static void DetectTlsIssuerRegisterTests(void);
60 #endif
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_cert_issuer_buffer_id = 0;
66 
67 /**
68  * \brief Registration function for keyword: tls.cert_issuer
69  */
71 {
72  sigmatch_table[DETECT_AL_TLS_CERT_ISSUER].name = "tls.cert_issuer";
73  sigmatch_table[DETECT_AL_TLS_CERT_ISSUER].alias = "tls_cert_issuer";
74  sigmatch_table[DETECT_AL_TLS_CERT_ISSUER].desc = "content modifier to match specifically and only on the TLS cert issuer buffer";
75  sigmatch_table[DETECT_AL_TLS_CERT_ISSUER].url = DOC_URL DOC_VERSION "/rules/tls-keywords.html#tls-cert-issuer";
76  sigmatch_table[DETECT_AL_TLS_CERT_ISSUER].Setup = DetectTlsIssuerSetup;
77 #ifdef UNITTESTS
78  sigmatch_table[DETECT_AL_TLS_CERT_ISSUER].RegisterTests = DetectTlsIssuerRegisterTests;
79 #endif
82 
86 
87  DetectAppLayerMpmRegister2("tls.cert_issuer", SIG_FLAG_TOCLIENT, 2,
90 
91  DetectBufferTypeSetDescriptionByName("tls.cert_issuer",
92  "TLS certificate issuer");
93 
94  g_tls_cert_issuer_buffer_id = DetectBufferTypeGetByName("tls.cert_issuer");
95 }
96 
97 
98 /**
99  * \brief this function setup the tls_cert_issuer modifier keyword used in the rule
100  *
101  * \param de_ctx Pointer to the Detection Engine Context
102  * \param s Pointer to the Signature to which the current keyword belongs
103  * \param str Should hold an empty string always
104  *
105  * \retval 0 On success
106  * \retval -1 On failure
107  */
108 static int DetectTlsIssuerSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
109 {
110  if (DetectBufferSetActiveList(s, g_tls_cert_issuer_buffer_id) < 0)
111  return -1;
112 
114  return -1;
115 
116  return 0;
117 }
118 
119 static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
120  const DetectEngineTransforms *transforms, Flow *f,
121  const uint8_t flow_flags, void *txv, const int list_id)
122 {
123  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
124  if (buffer->inspect == NULL) {
125  const SSLState *ssl_state = (SSLState *)f->alstate;
126 
127  if (ssl_state->server_connp.cert0_issuerdn == NULL) {
128  return NULL;
129  }
130 
131  const uint32_t data_len = strlen(ssl_state->server_connp.cert0_issuerdn);
132  const uint8_t *data = (uint8_t *)ssl_state->server_connp.cert0_issuerdn;
133 
134  InspectionBufferSetup(buffer, data, data_len);
135  InspectionBufferApplyTransforms(buffer, transforms);
136  }
137 
138  return buffer;
139 }
140 
141 #ifdef UNITTESTS
143 #endif
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect.h:1409
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1150
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
int PrefilterGenericMpmRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, const DetectMpmAppLayerRegistery *mpm_reg, int list_id)
SSLStateConnp server_connp
InspectionBuffer * InspectionBufferGet(DetectEngineThreadCtx *det_ctx, const int list_id)
const char * name
Definition: detect.h:1164
Signature container.
Definition: detect.h:496
main detection engine ctx
Definition: detect.h:724
SSLv[2.0|3.[0|1|2|3]] state structure.
void * alstate
Definition: flow.h:438
int DetectBufferTypeGetByName(const char *name)
#define str(s)
#define SIG_FLAG_TOCLIENT
Definition: detect.h:242
#define SIGMATCH_INFO_STICKY_BUFFER
Definition: detect.h:1356
void DetectAppLayerInspectEngineRegister2(const char *name, AppProto alproto, uint32_t dir, int progress, InspectEngineFuncPtr2 Callback2, InspectionBufferGetDataPtr GetData)
register inspect engine at start up time
int 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.
const char * desc
Definition: detect.h:1166
const char * alias
Definition: detect.h:1165
void InspectionBufferSetup(InspectionBuffer *buffer, const uint8_t *data, const uint32_t data_len)
setup the buffer with our initial data
void InspectionBufferApplyTransforms(InspectionBuffer *buffer, const DetectEngineTransforms *transforms)
#define SIGMATCH_NOOPT
Definition: detect.h:1332
const char * url
Definition: detect.h:1167
void DetectTlsIssuerRegister(void)
Registration function for keyword: tls.cert_issuer.
int DetectBufferSetActiveList(Signature *s, const int list)
const uint8_t * inspect
Definition: detect.h:347
#define DOC_URL
Definition: suricata.h:86
void DetectBufferTypeSetDescriptionByName(const char *name, const char *desc)
#define DOC_VERSION
Definition: suricata.h:91
uint16_t flags
Definition: detect.h:1158
Flow data structure.
Definition: flow.h:325
void(* RegisterTests)(void)
Definition: detect.h:1156
char * cert0_issuerdn
void DetectAppLayerMpmRegister2(const char *name, int direction, int priority, int(*PrefilterRegister)(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, const DetectMpmAppLayerRegistery *mpm_reg, int list_id), InspectionBufferGetDataPtr GetData, AppProto alproto, int tx_min_progress)
register a MPM engine