suricata
detect-krb5-msgtype.c
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1 /* Copyright (C) 2018-2020 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 Pierre Chifflier <chifflier@wzdftpd.net>
22  */
23 
24 #include "suricata-common.h"
25 #include "util-unittest.h"
26 #include "util-byte.h"
27 
28 #include "detect-parse.h"
29 #include "detect-engine.h"
30 
31 #include "detect-krb5-msgtype.h"
32 
33 #include "app-layer-krb5.h"
34 #include "rust.h"
35 
36 /**
37  * \brief Regex for parsing our keyword options
38  */
39 #define PARSE_REGEX "^\\s*([A-z0-9\\.]+|\"[A-z0-9_\\.]+\")\\s*$"
40 static DetectParseRegex parse_regex;
41 
42 /* Prototypes of functions registered in DetectKrb5MsgTypeRegister below */
43 static int DetectKrb5MsgTypeMatch (DetectEngineThreadCtx *, Flow *,
44  uint8_t, void *, void *, const Signature *,
45  const SigMatchCtx *);
46 static int DetectKrb5MsgTypeSetup (DetectEngineCtx *, Signature *, const char *);
47 static void DetectKrb5MsgTypeFree (DetectEngineCtx *, void *);
48 #ifdef UNITTESTS
49 static void DetectKrb5MsgTypeRegisterTests (void);
50 #endif
51 
52 static int DetectEngineInspectKRB5Generic(DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx,
53  const DetectEngineAppInspectionEngine *engine, const Signature *s, Flow *f, uint8_t flags,
54  void *alstate, void *txv, uint64_t tx_id);
55 
56 static int g_krb5_msg_type_list_id = 0;
57 
58 /**
59  * \brief Registration function for krb5_msg_type: keyword
60  *
61  * This function is called once in the 'lifetime' of the engine.
62  */
64 {
65  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].name = "krb5_msg_type";
66  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].desc = "match Kerberos 5 message type";
67  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].url = "/rules/kerberos-keywords.html#krb5-msg-type";
69  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].AppLayerTxMatch = DetectKrb5MsgTypeMatch;
70  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].Setup = DetectKrb5MsgTypeSetup;
71  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].Free = DetectKrb5MsgTypeFree;
72 #ifdef UNITTESTS
73  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].RegisterTests = DetectKrb5MsgTypeRegisterTests;
74 #endif
75 
77  DetectEngineInspectKRB5Generic, NULL);
78 
80  DetectEngineInspectKRB5Generic, NULL);
81 
82  /* set up the PCRE for keyword parsing */
83  DetectSetupParseRegexes(PARSE_REGEX, &parse_regex);
84 
85  g_krb5_msg_type_list_id = DetectBufferTypeRegister("krb5_msg_type");
86  SCLogDebug("g_krb5_msg_type_list_id %d", g_krb5_msg_type_list_id);
87 }
88 
89 static int DetectEngineInspectKRB5Generic(DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx,
90  const DetectEngineAppInspectionEngine *engine, const Signature *s, Flow *f, uint8_t flags,
91  void *alstate, void *txv, uint64_t tx_id)
92 {
94  de_ctx, det_ctx, s, engine->smd, f, flags, alstate, txv, tx_id);
95 }
96 
97 /**
98  * \brief This function is used to match KRB5 rule option on a packet
99  *
100  * \param t pointer to thread vars
101  * \param det_ctx pointer to the pattern matcher thread
102  * \param p pointer to the current packet
103  * \param m pointer to the sigmatch with context that we will cast into DetectKrb5Data
104  *
105  * \retval 0 no match
106  * \retval 1 match
107  */
108 static int DetectKrb5MsgTypeMatch (DetectEngineThreadCtx *det_ctx,
109  Flow *f, uint8_t flags, void *state,
110  void *txv, const Signature *s,
111  const SigMatchCtx *ctx)
112 {
113  uint32_t msg_type;
114  const DetectKrb5MsgTypeData *dd = (const DetectKrb5MsgTypeData *)ctx;
115 
116  SCEnter();
117 
118  rs_krb5_tx_get_msgtype(txv, &msg_type);
119 
120  if (dd->msg_type == msg_type)
121  SCReturnInt(1);
122 
123  SCReturnInt(0);
124 }
125 
126 /**
127  * \brief This function is used to parse options passed via krb5_msgtype: keyword
128  *
129  * \param krb5str Pointer to the user provided krb5_msg_type options
130  *
131  * \retval krb5d pointer to DetectKrb5Data on success
132  * \retval NULL on failure
133  */
134 static DetectKrb5MsgTypeData *DetectKrb5MsgTypeParse (const char *krb5str)
135 {
136  DetectKrb5MsgTypeData *krb5d = NULL;
137  char arg1[4] = "";
138  int ret = 0, res = 0;
139  size_t pcre2len;
140 
141  ret = DetectParsePcreExec(&parse_regex, krb5str, 0, 0);
142  if (ret != 2) {
143  SCLogError(SC_ERR_PCRE_MATCH, "parse error, ret %" PRId32 "", ret);
144  goto error;
145  }
146 
147  pcre2len = sizeof(arg1);
148  res = pcre2_substring_copy_bynumber(parse_regex.match, 1, (PCRE2_UCHAR8 *)arg1, &pcre2len);
149  if (res < 0) {
150  SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre2_substring_copy_bynumber failed");
151  goto error;
152  }
153 
154  krb5d = SCMalloc(sizeof (DetectKrb5MsgTypeData));
155  if (unlikely(krb5d == NULL))
156  goto error;
157  if (StringParseUint8(&krb5d->msg_type, 10, 0,
158  (const char *)arg1) < 0) {
159  goto error;
160  }
161  return krb5d;
162 
163 error:
164  if (krb5d)
165  SCFree(krb5d);
166  return NULL;
167 }
168 
169 /**
170  * \brief parse the options from the 'krb5_msg_type' keyword in the rule into
171  * the Signature data structure.
172  *
173  * \param de_ctx pointer to the Detection Engine Context
174  * \param s pointer to the Current Signature
175  * \param krb5str pointer to the user provided options
176  *
177  * \retval 0 on Success
178  * \retval -1 on Failure
179  */
180 static int DetectKrb5MsgTypeSetup (DetectEngineCtx *de_ctx, Signature *s, const char *krb5str)
181 {
182  DetectKrb5MsgTypeData *krb5d = NULL;
183  SigMatch *sm = NULL;
184 
186  return -1;
187 
188  krb5d = DetectKrb5MsgTypeParse(krb5str);
189  if (krb5d == NULL)
190  goto error;
191 
192  sm = SigMatchAlloc();
193  if (sm == NULL)
194  goto error;
195 
197  sm->ctx = (void *)krb5d;
198 
199  SigMatchAppendSMToList(s, sm, g_krb5_msg_type_list_id);
200 
201  return 0;
202 
203 error:
204  if (krb5d != NULL)
205  DetectKrb5MsgTypeFree(de_ctx, krb5d);
206  if (sm != NULL)
207  SCFree(sm);
208  return -1;
209 }
210 
211 /**
212  * \brief this function will free memory associated with DetectKrb5Data
213  *
214  * \param ptr pointer to DetectKrb5Data
215  */
216 static void DetectKrb5MsgTypeFree(DetectEngineCtx *de_ctx, void *ptr) {
218 
219  SCFree(krb5d);
220 }
221 
222 #ifdef UNITTESTS
223 
224 /**
225  * \test description of the test
226  */
227 
228 static int DetectKrb5MsgTypeParseTest01 (void)
229 {
230  DetectKrb5MsgTypeData *krb5d = DetectKrb5MsgTypeParse("10");
231  FAIL_IF_NULL(krb5d);
232  FAIL_IF(!(krb5d->msg_type == 10));
233  DetectKrb5MsgTypeFree(NULL, krb5d);
234  PASS;
235 }
236 
237 static int DetectKrb5MsgTypeSignatureTest01 (void)
238 {
241 
242  Signature *sig = DetectEngineAppendSig(de_ctx, "alert krb5 any any -> any any (krb5_msg_type:10; sid:1; rev:1;)");
243  FAIL_IF_NULL(sig);
244 
246  PASS;
247 }
248 
249 /**
250  * \brief this function registers unit tests for DetectKrb5MsgType
251  */
252 static void DetectKrb5MsgTypeRegisterTests(void)
253 {
254  UtRegisterTest("DetectKrb5MsgTypeParseTest01", DetectKrb5MsgTypeParseTest01);
255  UtRegisterTest("DetectKrb5MsgTypeSignatureTest01",
256  DetectKrb5MsgTypeSignatureTest01);
257 }
258 #endif /* UNITTESTS */
util-byte.h
DetectParseRegex::match
pcre2_match_data * match
Definition: detect-parse.h:45
DetectEngineAppInspectionEngine_
Definition: detect.h:398
SigTableElmt_::url
const char * url
Definition: detect.h:1270
DetectSignatureSetAppProto
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
Definition: detect-parse.c:1490
detect-engine.h
FAIL_IF_NULL
#define FAIL_IF_NULL(expr)
Fail a test if expression evaluates to NULL.
Definition: util-unittest.h:89
SigTableElmt_::desc
const char * desc
Definition: detect.h:1269
DetectParsePcreExec
int DetectParsePcreExec(DetectParseRegex *parse_regex, const char *str, int start_offset, int options)
Definition: detect-parse.c:2474
SigTableElmt_::Free
void(* Free)(DetectEngineCtx *, void *)
Definition: detect.h:1257
DetectEngineInspectGenericList
int DetectEngineInspectGenericList(const DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx, const Signature *s, const SigMatchData *smd, Flow *f, const uint8_t flags, void *alstate, void *txv, uint64_t tx_id)
Do the content inspection & validation for a signature.
Definition: detect-engine.c:1941
DetectParseRegex
Definition: detect-parse.h:42
SigTableElmt_::name
const char * name
Definition: detect.h:1267
unlikely
#define unlikely(expr)
Definition: util-optimize.h:35
UtRegisterTest
void UtRegisterTest(const char *name, int(*TestFn)(void))
Register unit test.
Definition: util-unittest.c:103
SCLogDebug
#define SCLogDebug(...)
Definition: util-debug.h:298
Flow_
Flow data structure.
Definition: flow.h:353
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:811
DetectEngineCtxFree
void DetectEngineCtxFree(DetectEngineCtx *)
Free a DetectEngineCtx::
Definition: detect-engine.c:2433
SigTableElmt_::AppLayerTxMatch
int(* AppLayerTxMatch)(DetectEngineThreadCtx *, Flow *, uint8_t flags, void *alstate, void *txv, const Signature *, const SigMatchCtx *)
Definition: detect.h:1238
rust.h
SC_ERR_PCRE_GET_SUBSTRING
@ SC_ERR_PCRE_GET_SUBSTRING
Definition: util-error.h:34
SIG_FLAG_TOCLIENT
#define SIG_FLAG_TOCLIENT
Definition: detect.h:237
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1252
util-unittest.h
ALPROTO_KRB5
@ ALPROTO_KRB5
Definition: app-layer-protos.h:50
app-layer-krb5.h
StringParseUint8
int StringParseUint8(uint8_t *res, int base, size_t len, const char *str)
Definition: util-byte.c:359
detect-krb5-msgtype.h
SIG_FLAG_TOSERVER
#define SIG_FLAG_TOSERVER
Definition: detect.h:236
SC_ERR_PCRE_MATCH
@ SC_ERR_PCRE_MATCH
Definition: util-error.h:32
PASS
#define PASS
Pass the test.
Definition: util-unittest.h:105
de_ctx
DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:17
DetectEngineThreadCtx_
Definition: detect.h:1060
res
PoolThreadReserved res
Definition: stream-tcp-private.h:0
DetectSetupParseRegexes
void DetectSetupParseRegexes(const char *parse_str, DetectParseRegex *detect_parse)
Definition: detect-parse.c:2597
SCEnter
#define SCEnter(...)
Definition: util-debug.h:300
SigMatch_::ctx
SigMatchCtx * ctx
Definition: detect.h:324
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:225
DETECT_AL_KRB5_MSGTYPE
@ DETECT_AL_KRB5_MSGTYPE
Definition: detect-engine-register.h:244
PARSE_REGEX
#define PARSE_REGEX
Regex for parsing our keyword options.
Definition: detect-krb5-msgtype.c:39
DetectKrb5MsgTypeData_
Definition: detect-krb5-msgtype.h:27
SigTableElmt_::Match
int(* Match)(DetectEngineThreadCtx *, Packet *, const Signature *, const SigMatchCtx *)
Definition: detect.h:1235
SigMatchAlloc
SigMatch * SigMatchAlloc(void)
Definition: detect-parse.c:235
SigMatchCtx_
Used to start a pointer to SigMatch context Should never be dereferenced without casting to something...
Definition: detect.h:316
DetectEngineAppInspectionEngine_::smd
SigMatchData * smd
Definition: detect.h:415
DetectEngineAppendSig
Signature * DetectEngineAppendSig(DetectEngineCtx *de_ctx, const char *sigstr)
Parse and append a Signature into the Detection Engine Context signature list.
Definition: detect-parse.c:2420
FAIL_IF
#define FAIL_IF(expr)
Fail a test if expression evaluates to true.
Definition: util-unittest.h:71
DetectBufferTypeRegister
int DetectBufferTypeRegister(const char *name)
Definition: detect-engine.c:1023
flags
uint8_t flags
Definition: decode-gre.h:0
suricata-common.h
SigMatch_::type
uint16_t type
Definition: detect.h:322
sigmatch_table
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect-parse.c:73
SCLogError
#define SCLogError(err_code,...)
Macro used to log ERROR messages.
Definition: util-debug.h:257
SCMalloc
#define SCMalloc(sz)
Definition: util-mem.h:47
DetectKrb5MsgTypeRegister
void DetectKrb5MsgTypeRegister(void)
Registration function for krb5_msg_type: keyword.
Definition: detect-krb5-msgtype.c:63
DetectKrb5MsgTypeData_::msg_type
uint8_t msg_type
Definition: detect-krb5-msgtype.h:28
SCFree
#define SCFree(p)
Definition: util-mem.h:61
detect-parse.h
Signature_
Signature container.
Definition: detect.h:548
SigMatch_
a single match condition for a signature
Definition: detect.h:321
DetectEngineCtxInit
DetectEngineCtx * DetectEngineCtxInit(void)
Definition: detect-engine.c:2394
SCReturnInt
#define SCReturnInt(x)
Definition: util-debug.h:304
SigMatchAppendSMToList
void SigMatchAppendSMToList(Signature *s, SigMatch *new, int list)
Append a SigMatch to the list type.
Definition: detect-parse.c:349
SigTableElmt_::RegisterTests
void(* RegisterTests)(void)
Definition: detect.h:1259