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 g_krb5_msg_type_list_id = 0;
53 
54 /**
55  * \brief Registration function for krb5_msg_type: keyword
56  *
57  * This function is called once in the 'lifetime' of the engine.
58  */
60 {
61  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].name = "krb5_msg_type";
62  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].desc = "match Kerberos 5 message type";
63  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].url = "/rules/kerberos-keywords.html#krb5-msg-type";
65  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].AppLayerTxMatch = DetectKrb5MsgTypeMatch;
66  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].Setup = DetectKrb5MsgTypeSetup;
67  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].Free = DetectKrb5MsgTypeFree;
68 #ifdef UNITTESTS
69  sigmatch_table[DETECT_AL_KRB5_MSGTYPE].RegisterTests = DetectKrb5MsgTypeRegisterTests;
70 #endif
71 
74 
77 
78  /* set up the PCRE for keyword parsing */
79  DetectSetupParseRegexes(PARSE_REGEX, &parse_regex);
80 
81  g_krb5_msg_type_list_id = DetectBufferTypeRegister("krb5_msg_type");
82  SCLogDebug("g_krb5_msg_type_list_id %d", g_krb5_msg_type_list_id);
83 }
84 
85 /**
86  * \brief This function is used to match KRB5 rule option on a packet
87  *
88  * \param t pointer to thread vars
89  * \param det_ctx pointer to the pattern matcher thread
90  * \param p pointer to the current packet
91  * \param m pointer to the sigmatch with context that we will cast into DetectKrb5Data
92  *
93  * \retval 0 no match
94  * \retval 1 match
95  */
96 static int DetectKrb5MsgTypeMatch (DetectEngineThreadCtx *det_ctx,
97  Flow *f, uint8_t flags, void *state,
98  void *txv, const Signature *s,
99  const SigMatchCtx *ctx)
100 {
101  uint32_t msg_type;
102  const DetectKrb5MsgTypeData *dd = (const DetectKrb5MsgTypeData *)ctx;
103 
104  SCEnter();
105 
106  rs_krb5_tx_get_msgtype(txv, &msg_type);
107 
108  if (dd->msg_type == msg_type)
109  SCReturnInt(1);
110 
111  SCReturnInt(0);
112 }
113 
114 /**
115  * \brief This function is used to parse options passed via krb5_msgtype: keyword
116  *
117  * \param krb5str Pointer to the user provided krb5_msg_type options
118  *
119  * \retval krb5d pointer to DetectKrb5Data on success
120  * \retval NULL on failure
121  */
122 static DetectKrb5MsgTypeData *DetectKrb5MsgTypeParse (const char *krb5str)
123 {
124  DetectKrb5MsgTypeData *krb5d = NULL;
125  char arg1[4] = "";
126  int ret = 0, res = 0;
127  size_t pcre2len;
128 
129  ret = DetectParsePcreExec(&parse_regex, krb5str, 0, 0);
130  if (ret != 2) {
131  SCLogError(SC_ERR_PCRE_MATCH, "parse error, ret %" PRId32 "", ret);
132  goto error;
133  }
134 
135  pcre2len = sizeof(arg1);
136  res = pcre2_substring_copy_bynumber(parse_regex.match, 1, (PCRE2_UCHAR8 *)arg1, &pcre2len);
137  if (res < 0) {
138  SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre2_substring_copy_bynumber failed");
139  goto error;
140  }
141 
142  krb5d = SCMalloc(sizeof (DetectKrb5MsgTypeData));
143  if (unlikely(krb5d == NULL))
144  goto error;
145  if (StringParseUint8(&krb5d->msg_type, 10, 0,
146  (const char *)arg1) < 0) {
147  goto error;
148  }
149  return krb5d;
150 
151 error:
152  if (krb5d)
153  SCFree(krb5d);
154  return NULL;
155 }
156 
157 /**
158  * \brief parse the options from the 'krb5_msg_type' keyword in the rule into
159  * the Signature data structure.
160  *
161  * \param de_ctx pointer to the Detection Engine Context
162  * \param s pointer to the Current Signature
163  * \param krb5str pointer to the user provided options
164  *
165  * \retval 0 on Success
166  * \retval -1 on Failure
167  */
168 static int DetectKrb5MsgTypeSetup (DetectEngineCtx *de_ctx, Signature *s, const char *krb5str)
169 {
170  DetectKrb5MsgTypeData *krb5d = NULL;
171  SigMatch *sm = NULL;
172 
174  return -1;
175 
176  krb5d = DetectKrb5MsgTypeParse(krb5str);
177  if (krb5d == NULL)
178  goto error;
179 
180  sm = SigMatchAlloc();
181  if (sm == NULL)
182  goto error;
183 
185  sm->ctx = (void *)krb5d;
186 
187  SigMatchAppendSMToList(s, sm, g_krb5_msg_type_list_id);
188 
189  return 0;
190 
191 error:
192  if (krb5d != NULL)
193  DetectKrb5MsgTypeFree(de_ctx, krb5d);
194  if (sm != NULL)
195  SCFree(sm);
196  return -1;
197 }
198 
199 /**
200  * \brief this function will free memory associated with DetectKrb5Data
201  *
202  * \param ptr pointer to DetectKrb5Data
203  */
204 static void DetectKrb5MsgTypeFree(DetectEngineCtx *de_ctx, void *ptr) {
206 
207  SCFree(krb5d);
208 }
209 
210 #ifdef UNITTESTS
211 
212 /**
213  * \test description of the test
214  */
215 
216 static int DetectKrb5MsgTypeParseTest01 (void)
217 {
218  DetectKrb5MsgTypeData *krb5d = DetectKrb5MsgTypeParse("10");
219  FAIL_IF_NULL(krb5d);
220  FAIL_IF(!(krb5d->msg_type == 10));
221  DetectKrb5MsgTypeFree(NULL, krb5d);
222  PASS;
223 }
224 
225 static int DetectKrb5MsgTypeSignatureTest01 (void)
226 {
229 
230  Signature *sig = DetectEngineAppendSig(de_ctx, "alert krb5 any any -> any any (krb5_msg_type:10; sid:1; rev:1;)");
231  FAIL_IF_NULL(sig);
232 
234  PASS;
235 }
236 
237 /**
238  * \brief this function registers unit tests for DetectKrb5MsgType
239  */
240 static void DetectKrb5MsgTypeRegisterTests(void)
241 {
242  UtRegisterTest("DetectKrb5MsgTypeParseTest01", DetectKrb5MsgTypeParseTest01);
243  UtRegisterTest("DetectKrb5MsgTypeSignatureTest01",
244  DetectKrb5MsgTypeSignatureTest01);
245 }
246 #endif /* UNITTESTS */
util-byte.h
DetectParseRegex::match
pcre2_match_data * match
Definition: detect-parse.h:47
SigTableElmt_::url
const char * url
Definition: detect.h:1238
DetectSignatureSetAppProto
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
Definition: detect-parse.c:1493
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:1237
DetectParsePcreExec
int DetectParsePcreExec(DetectParseRegex *parse_regex, const char *str, int start_offset, int options)
Definition: detect-parse.c:2488
SigTableElmt_::Free
void(* Free)(DetectEngineCtx *, void *)
Definition: detect.h:1225
DetectParseRegex
Definition: detect-parse.h:44
SigTableElmt_::name
const char * name
Definition: detect.h:1235
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:296
Flow_
Flow data structure.
Definition: flow.h:356
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:784
DetectEngineCtxFree
void DetectEngineCtxFree(DetectEngineCtx *)
Free a DetectEngineCtx::
Definition: detect-engine.c:2445
SigTableElmt_::AppLayerTxMatch
int(* AppLayerTxMatch)(DetectEngineThreadCtx *, Flow *, uint8_t flags, void *alstate, void *txv, const Signature *, const SigMatchCtx *)
Definition: detect.h:1206
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:229
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1220
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:228
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:1024
DetectSetupParseRegexes
void DetectSetupParseRegexes(const char *parse_str, DetectParseRegex *detect_parse)
Definition: detect-parse.c:2611
SCEnter
#define SCEnter(...)
Definition: util-debug.h:298
SigMatch_::ctx
SigMatchCtx * ctx
Definition: detect.h:316
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:228
DETECT_AL_KRB5_MSGTYPE
@ DETECT_AL_KRB5_MSGTYPE
Definition: detect-engine-register.h:254
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:1203
SigMatchAlloc
SigMatch * SigMatchAlloc(void)
Definition: detect-parse.c:238
SigMatchCtx_
Used to start a pointer to SigMatch context Should never be dereferenced without casting to something...
Definition: detect.h:308
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:2434
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:1032
flags
uint8_t flags
Definition: decode-gre.h:0
suricata-common.h
SigMatch_::type
uint16_t type
Definition: detect.h:314
sigmatch_table
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect-parse.c:76
SCLogError
#define SCLogError(err_code,...)
Macro used to log ERROR messages.
Definition: util-debug.h:255
DetectEngineInspectGenericList
uint8_t DetectEngineInspectGenericList(DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx, const struct 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.
Definition: detect-engine.c:1951
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:59
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:539
SigMatch_
a single match condition for a signature
Definition: detect.h:313
DetectEngineCtxInit
DetectEngineCtx * DetectEngineCtxInit(void)
Definition: detect-engine.c:2406
SCReturnInt
#define SCReturnInt(x)
Definition: util-debug.h:302
SigMatchAppendSMToList
void SigMatchAppendSMToList(Signature *s, SigMatch *new, int list)
Append a SigMatch to the list type.
Definition: detect-parse.c:352
SigTableElmt_::RegisterTests
void(* RegisterTests)(void)
Definition: detect.h:1227