suricata
detect-ssh-proto.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  * \ingroup sshlayer
20  *
21  * @{
22  */
23 
24 
25 /**
26  * \file
27  *
28  * \author Victor Julien <victor@inliniac.net>
29  *
30  * Implements support ssh_proto sticky buffer
31  */
32 
33 #include "suricata-common.h"
34 #include "threads.h"
35 #include "decode.h"
36 
37 #include "detect.h"
38 #include "detect-parse.h"
39 #include "detect-engine.h"
40 #include "detect-engine-mpm.h"
41 #include "detect-engine-state.h"
44 
45 #include "app-layer.h"
46 #include "app-layer-parser.h"
47 #include "app-layer-ssh.h"
48 #include "detect-ssh-proto.h"
49 
50 #define KEYWORD_NAME "ssh.proto"
51 #define KEYWORD_NAME_LEGACY "ssh_proto"
52 #define KEYWORD_DOC "ssh-keywords.html#ssh-proto"
53 #define BUFFER_NAME "ssh_protocol"
54 #define BUFFER_DESC "ssh protocol field"
55 static int g_buffer_id = 0;
56 
57 static InspectionBuffer *GetSshData(DetectEngineThreadCtx *det_ctx,
58  const DetectEngineTransforms *transforms, Flow *_f,
59  const uint8_t flow_flags, void *txv, const int list_id)
60 {
61  SCEnter();
62 
63  InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
64 
65  if (buffer->inspect == NULL) {
66  uint8_t *protocol = NULL;
67  SshState *ssh_state = (SshState *) txv;
68 
69  if (flow_flags & STREAM_TOSERVER)
70  protocol = ssh_state->cli_hdr.proto_version;
71  else if (flow_flags & STREAM_TOCLIENT)
72  protocol = ssh_state->srv_hdr.proto_version;
73 
74  if (protocol == NULL) {
75  SCLogDebug("SSL protocol not set");
76  return NULL;
77  }
78 
79  uint32_t data_len = strlen((char *)protocol);
80  uint8_t *data = protocol;
81  if (data == NULL || data_len == 0) {
82  SCLogDebug("SSL protocol not present");
83  return NULL;
84  }
85 
86  InspectionBufferSetup(buffer, data, data_len);
87  InspectionBufferApplyTransforms(buffer, transforms);
88  }
89 
90  return buffer;
91 }
92 
93 static int DetectSshProtocolSetup(DetectEngineCtx *de_ctx, Signature *s, const char *arg)
94 {
95  if (DetectBufferSetActiveList(s, g_buffer_id) < 0)
96  return -1;
97 
99  return -1;
100 
101  return 0;
102 }
103 
105 {
110  sigmatch_table[DETECT_AL_SSH_PROTOCOL].Setup = DetectSshProtocolSetup;
112 
113 
115  PrefilterGenericMpmRegister, GetSshData,
118  PrefilterGenericMpmRegister, GetSshData,
120 
127 
129 
130  g_buffer_id = DetectBufferTypeGetByName(BUFFER_NAME);
131 }
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect.h:1439
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1179
SshHeader cli_hdr
Definition: app-layer-ssh.h:74
#define SCLogDebug(...)
Definition: util-debug.h:335
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
#define KEYWORD_NAME
uint8_t * proto_version
Definition: app-layer-ssh.h:60
InspectionBuffer * InspectionBufferGet(DetectEngineThreadCtx *det_ctx, const int list_id)
#define KEYWORD_DOC
const char * name
Definition: detect.h:1193
uint16_t protocol
Definition: decode-ppp.h:313
Signature container.
Definition: detect.h:517
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
main detection engine ctx
Definition: detect.h:756
int DetectBufferTypeGetByName(const char *name)
#define SIG_FLAG_TOCLIENT
Definition: detect.h:233
#define SIGMATCH_INFO_STICKY_BUFFER
Definition: detect.h:1386
#define BUFFER_DESC
SshHeader srv_hdr
Definition: app-layer-ssh.h:73
Data structures and function prototypes for keeping state for the detection engine.
#define SIG_FLAG_TOSERVER
Definition: detect.h:232
#define SCEnter(...)
Definition: util-debug.h:337
void DetectAppLayerInspectEngineRegister2(const char *name, AppProto alproto, uint32_t dir, int progress, InspectEngineFuncPtr2 Callback2, InspectionBufferGetDataPtr GetData)
register inspect engine at start up time
#define STREAM_TOCLIENT
Definition: stream.h:32
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.
#define BUFFER_NAME
const char * desc
Definition: detect.h:1195
int PrefilterGenericMpmRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, const DetectBufferMpmRegistery *mpm_reg, int list_id)
const char * alias
Definition: detect.h:1194
#define KEYWORD_NAME_LEGACY
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:1362
const char * url
Definition: detect.h:1196
#define STREAM_TOSERVER
Definition: stream.h:31
int DetectBufferSetActiveList(Signature *s, const int list)
const uint8_t * inspect
Definition: detect.h:338
#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:1187
void DetectSshProtocolRegister(void)
Flow data structure.
Definition: flow.h:325