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 
27 #include "detect-parse.h"
28 #include "detect-engine.h"
29 
30 #include "detect-krb5-msgtype.h"
31 
32 #include "app-layer-krb5.h"
33 #include "rust.h"
34 
35 /**
36  * \brief Regex for parsing our keyword options
37  */
38 #define PARSE_REGEX "^\\s*([A-z0-9\\.]+|\"[A-z0-9_\\.]+\")\\s*$"
39 static DetectParseRegex parse_regex;
40 
41 /* Prototypes of functions registered in DetectKrb5MsgTypeRegister below */
42 static int DetectKrb5MsgTypeMatch (DetectEngineThreadCtx *, Flow *,
43  uint8_t, void *, void *, const Signature *,
44  const SigMatchCtx *);
45 static int DetectKrb5MsgTypeSetup (DetectEngineCtx *, Signature *, const char *);
46 static void DetectKrb5MsgTypeFree (DetectEngineCtx *, void *);
47 static void DetectKrb5MsgTypeRegisterTests (void);
48 
49 static int DetectEngineInspectKRB5Generic(ThreadVars *tv,
51  const Signature *s, const SigMatchData *smd,
52  Flow *f, uint8_t flags, void *alstate,
53  void *txv, uint64_t tx_id);
54 
55 static int g_krb5_msg_type_list_id = 0;
56 
57 /**
58  * \brief Registration function for krb5_msg_type: keyword
59  *
60  * This function is called once in the 'lifetime' of the engine.
61  */
63  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].name = "krb5_msg_type";
64  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].desc = "match Kerberos 5 message type";
65  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].url = "/rules/kerberos-keywords.html#krb5-msg-type";
67  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].AppLayerTxMatch = DetectKrb5MsgTypeMatch;
68  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].Setup = DetectKrb5MsgTypeSetup;
69  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].Free = DetectKrb5MsgTypeFree;
70  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].RegisterTests = DetectKrb5MsgTypeRegisterTests;
71 
74  DetectEngineInspectKRB5Generic);
75 
78  DetectEngineInspectKRB5Generic);
79 
80  /* set up the PCRE for keyword parsing */
81  DetectSetupParseRegexes(PARSE_REGEX, &parse_regex);
82 
83  g_krb5_msg_type_list_id = DetectBufferTypeRegister("krb5_msg_type");
84  SCLogDebug("g_krb5_msg_type_list_id %d", g_krb5_msg_type_list_id);
85 }
86 
87 static int DetectEngineInspectKRB5Generic(ThreadVars *tv,
89  const Signature *s, const SigMatchData *smd,
90  Flow *f, uint8_t flags, void *alstate,
91  void *txv, uint64_t tx_id)
92 {
93  return DetectEngineInspectGenericList(tv, de_ctx, det_ctx, s, smd,
94  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  int ov[MAX_SUBSTRINGS];
140 
141  ret = DetectParsePcreExec(&parse_regex, krb5str, 0, 0, ov, MAX_SUBSTRINGS);
142  if (ret != 2) {
143  SCLogError(SC_ERR_PCRE_MATCH, "parse error, ret %" PRId32 "", ret);
144  goto error;
145  }
146 
147  res = pcre_copy_substring((char *) krb5str, ov, MAX_SUBSTRINGS, 1, arg1, sizeof(arg1));
148  if (res < 0) {
149  SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_copy_substring failed");
150  goto error;
151  }
152 
153  krb5d = SCMalloc(sizeof (DetectKrb5MsgTypeData));
154  if (unlikely(krb5d == NULL))
155  goto error;
156  krb5d->msg_type = (uint8_t)atoi(arg1);
157 
158  return krb5d;
159 
160 error:
161  if (krb5d)
162  SCFree(krb5d);
163  return NULL;
164 }
165 
166 /**
167  * \brief parse the options from the 'krb5_msg_type' keyword in the rule into
168  * the Signature data structure.
169  *
170  * \param de_ctx pointer to the Detection Engine Context
171  * \param s pointer to the Current Signature
172  * \param krb5str pointer to the user provided options
173  *
174  * \retval 0 on Success
175  * \retval -1 on Failure
176  */
177 static int DetectKrb5MsgTypeSetup (DetectEngineCtx *de_ctx, Signature *s, const char *krb5str)
178 {
179  DetectKrb5MsgTypeData *krb5d = NULL;
180  SigMatch *sm = NULL;
181 
183  return -1;
184 
185  krb5d = DetectKrb5MsgTypeParse(krb5str);
186  if (krb5d == NULL)
187  goto error;
188 
189  sm = SigMatchAlloc();
190  if (sm == NULL)
191  goto error;
192 
194  sm->ctx = (void *)krb5d;
195 
196  SigMatchAppendSMToList(s, sm, g_krb5_msg_type_list_id);
197 
198  return 0;
199 
200 error:
201  if (krb5d != NULL)
202  DetectKrb5MsgTypeFree(de_ctx, krb5d);
203  if (sm != NULL)
204  SCFree(sm);
205  return -1;
206 }
207 
208 /**
209  * \brief this function will free memory associated with DetectKrb5Data
210  *
211  * \param ptr pointer to DetectKrb5Data
212  */
213 static void DetectKrb5MsgTypeFree(DetectEngineCtx *de_ctx, void *ptr) {
215 
216  SCFree(krb5d);
217 }
218 
219 #ifdef UNITTESTS
220 
221 /**
222  * \test description of the test
223  */
224 
225 static int DetectKrb5MsgTypeParseTest01 (void)
226 {
227  DetectKrb5MsgTypeData *krb5d = DetectKrb5MsgTypeParse("10");
228  FAIL_IF_NULL(krb5d);
229  FAIL_IF(!(krb5d->msg_type == 10));
230  DetectKrb5MsgTypeFree(NULL, krb5d);
231  PASS;
232 }
233 
234 static int DetectKrb5MsgTypeSignatureTest01 (void)
235 {
238 
239  Signature *sig = DetectEngineAppendSig(de_ctx, "alert krb5 any any -> any any (krb5_msg_type:10; sid:1; rev:1;)");
240  FAIL_IF_NULL(sig);
241 
243  PASS;
244 }
245 
246 #endif /* UNITTESTS */
247 
248 /**
249  * \brief this function registers unit tests for DetectKrb5MsgType
250  */
251 static void DetectKrb5MsgTypeRegisterTests(void) {
252 #ifdef UNITTESTS
253  UtRegisterTest("DetectKrb5MsgTypeParseTest01", DetectKrb5MsgTypeParseTest01);
254  UtRegisterTest("DetectKrb5MsgTypeSignatureTest01",
255  DetectKrb5MsgTypeSignatureTest01);
256 #endif /* UNITTESTS */
257 }
SigTableElmt_::url
const char * url
Definition: detect.h:1212
DetectSignatureSetAppProto
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
Definition: detect-parse.c:1468
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:1211
SigTableElmt_::Free
void(* Free)(DetectEngineCtx *, void *)
Definition: detect.h:1200
SigTableElmt_::name
const char * name
Definition: detect.h:1209
MAX_SUBSTRINGS
#define MAX_SUBSTRINGS
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:343
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:766
DetectEngineCtxFree
void DetectEngineCtxFree(DetectEngineCtx *)
Free a DetectEngineCtx::
Definition: detect-engine.c:2089
SigTableElmt_::AppLayerTxMatch
int(* AppLayerTxMatch)(DetectEngineThreadCtx *, Flow *, uint8_t flags, void *alstate, void *txv, const Signature *, const SigMatchCtx *)
Definition: detect.h:1181
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
SigMatchData_
Data needed for Match()
Definition: detect.h:328
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1195
util-unittest.h
DetectEngineInspectGenericList
int DetectEngineInspectGenericList(ThreadVars *tv, 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:1592
ALPROTO_KRB5
@ ALPROTO_KRB5
Definition: app-layer-protos.h:50
app-layer-krb5.h
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:1009
res
PoolThreadReserved res
Definition: stream-tcp-private.h:0
DetectSetupParseRegexes
void DetectSetupParseRegexes(const char *parse_str, DetectParseRegex *detect_parse)
Definition: detect-parse.c:2456
SCEnter
#define SCEnter(...)
Definition: util-debug.h:300
ThreadVars_
Per thread variable structure.
Definition: threadvars.h:58
SigMatch_::ctx
SigMatchCtx * ctx
Definition: detect.h:322
DetectParsePcreExec
int DetectParsePcreExec(DetectParseRegex *parse_regex, const char *str, int start_offset, int options, int *ovector, int ovector_size)
Definition: detect-parse.c:2388
DETECT_AL_KRB5_MSGTYPE
@ DETECT_AL_KRB5_MSGTYPE
Definition: detect-engine-register.h:225
PARSE_REGEX
#define PARSE_REGEX
Regex for parsing our keyword options.
Definition: detect-krb5-msgtype.c:38
DetectKrb5MsgTypeData_
Definition: detect-krb5-msgtype.h:27
SigTableElmt_::Match
int(* Match)(DetectEngineThreadCtx *, Packet *, const Signature *, const SigMatchCtx *)
Definition: detect.h:1178
SigMatchAlloc
SigMatch * SigMatchAlloc(void)
Definition: detect-parse.c:235
SigMatch_::type
uint8_t type
Definition: detect.h:320
SigMatchCtx_
Used to start a pointer to SigMatch context Should never be dereferenced without casting to something...
Definition: detect.h:314
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:2326
FAIL_IF
#define FAIL_IF(expr)
Fail a test if expression evaluates to false.
Definition: util-unittest.h:71
DetectBufferTypeRegister
int DetectBufferTypeRegister(const char *name)
Definition: detect-engine.c:832
flags
uint8_t flags
Definition: decode-gre.h:0
suricata-common.h
sigmatch_table
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect-parse.c:73
DetectParseRegex_
Definition: detect-parse.h:42
SCLogError
#define SCLogError(err_code,...)
Macro used to log ERROR messages.
Definition: util-debug.h:257
tv
ThreadVars * tv
Definition: fuzz_decodepcapfile.c:29
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:62
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:527
SigMatch_
a single match condition for a signature
Definition: detect.h:319
DetectEngineCtxInit
DetectEngineCtx * DetectEngineCtxInit(void)
Definition: detect-engine.c:2044
DetectAppLayerInspectEngineRegister
void DetectAppLayerInspectEngineRegister(const char *name, AppProto alproto, uint32_t dir, int progress, InspectEngineFuncPtr Callback)
register inspect engine at start up time
Definition: detect-engine.c:170
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:1201