1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
/* Copyright (C) 2018-2022 Open Information Security Foundation
*
* You can copy, redistribute or modify this Program under the terms of
* the GNU General Public License version 2 as published by the Free
* Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
/**
* \file
*
* \author Pierre Chifflier <chifflier@wzdftpd.net>
*/
#include "suricata-common.h"
#include "util-unittest.h"
#include "detect-parse.h"
#include "detect-engine.h"
#include "detect-engine-mpm.h"
#include "detect-engine-state.h"
#include "detect-engine-prefilter.h"
#include "detect-engine-content-inspection.h"
#include "detect-krb5-cname.h"
#include "rust.h"
#include "app-layer-krb5.h"
#include "util-profiling.h"
static int g_krb5_cname_buffer_id = 0;
struct Krb5PrincipalNameDataArgs {
uint32_t local_id; /**< used as index into thread inspect array */
void *txv;
};
static int DetectKrb5CNameSetup(DetectEngineCtx *de_ctx, Signature *s, const char *arg)
{
if (DetectBufferSetActiveList(de_ctx, s, g_krb5_cname_buffer_id) < 0)
return -1;
if (DetectSignatureSetAppProto(s, ALPROTO_KRB5) != 0)
return -1;
return 0;
}
static InspectionBuffer *GetKrb5CNameData(DetectEngineThreadCtx *det_ctx,
const DetectEngineTransforms *transforms, Flow *_f,
const struct Krb5PrincipalNameDataArgs *cbdata, int list_id)
{
SCEnter();
InspectionBuffer *buffer =
InspectionBufferMultipleForListGet(det_ctx, list_id, cbdata->local_id);
if (buffer == NULL)
return NULL;
if (buffer->initialized)
return buffer;
uint32_t b_len = 0;
const uint8_t *b = NULL;
if (rs_krb5_tx_get_cname(cbdata->txv, cbdata->local_id, &b, &b_len) != 1) {
InspectionBufferSetupMultiEmpty(buffer);
return NULL;
}
if (b == NULL || b_len == 0) {
InspectionBufferSetupMultiEmpty(buffer);
return NULL;
}
InspectionBufferSetupMulti(buffer, transforms, b, b_len);
SCReturnPtr(buffer, "InspectionBuffer");
}
static uint8_t DetectEngineInspectKrb5CName(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)
{
uint32_t local_id = 0;
const DetectEngineTransforms *transforms = NULL;
if (!engine->mpm) {
transforms = engine->v2.transforms;
}
while (1) {
struct Krb5PrincipalNameDataArgs cbdata = { local_id, txv, };
InspectionBuffer *buffer =
GetKrb5CNameData(det_ctx, transforms, f, &cbdata, engine->sm_list);
if (buffer == NULL || buffer->inspect == NULL)
break;
det_ctx->buffer_offset = 0;
det_ctx->discontinue_matching = 0;
det_ctx->inspection_recursion_counter = 0;
const int match = DetectEngineContentInspection(de_ctx, det_ctx, s, engine->smd,
NULL, f,
(uint8_t *)buffer->inspect,
buffer->inspect_len,
buffer->inspect_offset, DETECT_CI_FLAGS_SINGLE,
DETECT_ENGINE_CONTENT_INSPECTION_MODE_STATE);
if (match == 1) {
return DETECT_ENGINE_INSPECT_SIG_MATCH;
}
local_id++;
}
return DETECT_ENGINE_INSPECT_SIG_NO_MATCH;
}
typedef struct PrefilterMpmKrb5Name {
int list_id;
const MpmCtx *mpm_ctx;
const DetectEngineTransforms *transforms;
} PrefilterMpmKrb5Name;
/** \brief Krb5CName Krb5CName Mpm prefilter callback
*
* \param det_ctx detection engine thread ctx
* \param p packet to inspect
* \param f flow to inspect
* \param txv tx to inspect
* \param pectx inspection context
*/
static void PrefilterTxKrb5CName(DetectEngineThreadCtx *det_ctx, const void *pectx, Packet *p,
Flow *f, void *txv, const uint64_t idx, const AppLayerTxData *_txd, const uint8_t flags)
{
SCEnter();
const PrefilterMpmKrb5Name *ctx = (const PrefilterMpmKrb5Name *)pectx;
const MpmCtx *mpm_ctx = ctx->mpm_ctx;
const int list_id = ctx->list_id;
uint32_t local_id = 0;
while(1) {
// loop until we get a NULL
struct Krb5PrincipalNameDataArgs cbdata = { local_id, txv };
InspectionBuffer *buffer = GetKrb5CNameData(det_ctx, ctx->transforms, f, &cbdata, list_id);
if (buffer == NULL)
break;
if (buffer->inspect_len >= mpm_ctx->minlen) {
(void)mpm_table[mpm_ctx->mpm_type].Search(mpm_ctx,
&det_ctx->mtcu, &det_ctx->pmq,
buffer->inspect, buffer->inspect_len);
PREFILTER_PROFILING_ADD_BYTES(det_ctx, buffer->inspect_len);
}
local_id++;
}
}
static void PrefilterMpmKrb5NameFree(void *ptr)
{
SCFree(ptr);
}
static int PrefilterMpmKrb5CNameRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh,
MpmCtx *mpm_ctx, const DetectBufferMpmRegistry *mpm_reg, int list_id)
{
PrefilterMpmKrb5Name *pectx = SCCalloc(1, sizeof(*pectx));
if (pectx == NULL)
return -1;
pectx->list_id = list_id;
pectx->mpm_ctx = mpm_ctx;
pectx->transforms = &mpm_reg->transforms;
return PrefilterAppendTxEngine(de_ctx, sgh, PrefilterTxKrb5CName,
mpm_reg->app_v2.alproto, mpm_reg->app_v2.tx_min_progress,
pectx, PrefilterMpmKrb5NameFree, mpm_reg->name);
}
void DetectKrb5CNameRegister(void)
{
sigmatch_table[DETECT_AL_KRB5_CNAME].name = "krb5.cname";
sigmatch_table[DETECT_AL_KRB5_CNAME].alias = "krb5_cname";
sigmatch_table[DETECT_AL_KRB5_CNAME].url = "/rules/kerberos-keywords.html#krb5-cname";
sigmatch_table[DETECT_AL_KRB5_CNAME].Setup = DetectKrb5CNameSetup;
sigmatch_table[DETECT_AL_KRB5_CNAME].flags |= SIGMATCH_NOOPT|SIGMATCH_INFO_STICKY_BUFFER;
sigmatch_table[DETECT_AL_KRB5_CNAME].desc = "sticky buffer to match on Kerberos 5 client name";
DetectAppLayerMpmRegister2("krb5_cname", SIG_FLAG_TOCLIENT, 2,
PrefilterMpmKrb5CNameRegister, NULL,
ALPROTO_KRB5, 1);
DetectAppLayerInspectEngineRegister2("krb5_cname",
ALPROTO_KRB5, SIG_FLAG_TOCLIENT, 0,
DetectEngineInspectKrb5CName, NULL);
DetectBufferTypeSetDescriptionByName("krb5_cname",
"Kerberos 5 ticket client name");
g_krb5_cname_buffer_id = DetectBufferTypeGetByName("krb5_cname");
DetectBufferTypeSupportsMultiInstance("krb5_cname");
}
|
