suricata
detect-krb5-errcode.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-errcode.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 DetectKrb5ErrCodeRegister below */
43 static int DetectKrb5ErrCodeMatch (DetectEngineThreadCtx *, Flow *,
44  uint8_t, void *, void *, const Signature *,
45  const SigMatchCtx *);
46 static int DetectKrb5ErrCodeSetup (DetectEngineCtx *, Signature *, const char *);
47 static void DetectKrb5ErrCodeFree (DetectEngineCtx *, void *);
48 #ifdef UNITTESTS
49 static void DetectKrb5ErrCodeRegisterTests (void);
50 #endif
51 
52 static int DetectEngineInspectKRB5Generic(ThreadVars *tv,
54  const Signature *s, const SigMatchData *smd,
55  Flow *f, uint8_t flags, void *alstate,
56  void *txv, uint64_t tx_id);
57 
58 static int g_krb5_err_code_list_id = 0;
59 
60 /**
61  * \brief Registration function for krb5_err_code: keyword
62  *
63  * This function is called once in the 'lifetime' of the engine.
64  */
66 {
67  sigmatch_table[DETECT_AL_KRB5_ERRCODE].name = "krb5_err_code";
68  sigmatch_table[DETECT_AL_KRB5_ERRCODE].desc = "match Kerberos 5 error code";
69  sigmatch_table[DETECT_AL_KRB5_ERRCODE].url = "/rules/kerberos-keywords.html#krb5-err-code";
71  sigmatch_table[DETECT_AL_KRB5_ERRCODE].AppLayerTxMatch = DetectKrb5ErrCodeMatch;
72  sigmatch_table[DETECT_AL_KRB5_ERRCODE].Setup = DetectKrb5ErrCodeSetup;
73  sigmatch_table[DETECT_AL_KRB5_ERRCODE].Free = DetectKrb5ErrCodeFree;
74 #ifdef UNITTESTS
75  sigmatch_table[DETECT_AL_KRB5_ERRCODE].RegisterTests = DetectKrb5ErrCodeRegisterTests;
76 #endif
79  DetectEngineInspectKRB5Generic);
80 
83  DetectEngineInspectKRB5Generic);
84 
85  /* set up the PCRE for keyword parsing */
86  DetectSetupParseRegexes(PARSE_REGEX, &parse_regex);
87 
88  g_krb5_err_code_list_id = DetectBufferTypeRegister("krb5_err_code");
89  SCLogDebug("g_krb5_err_code_list_id %d", g_krb5_err_code_list_id);
90 }
91 
92 static int DetectEngineInspectKRB5Generic(ThreadVars *tv,
94  const Signature *s, const SigMatchData *smd,
95  Flow *f, uint8_t flags, void *alstate,
96  void *txv, uint64_t tx_id)
97 {
98  return DetectEngineInspectGenericList(tv, de_ctx, det_ctx, s, smd,
99  f, flags, alstate, txv, tx_id);
100 }
101 
102 /**
103  * \brief This function is used to match KRB5 rule option on a packet
104  *
105  * \param t pointer to thread vars
106  * \param det_ctx pointer to the pattern matcher thread
107  * \param p pointer to the current packet
108  * \param m pointer to the sigmatch with context that we will cast into DetectKrb5Data
109  *
110  * \retval 0 no match
111  * \retval 1 match
112  */
113 static int DetectKrb5ErrCodeMatch (DetectEngineThreadCtx *det_ctx,
114  Flow *f, uint8_t flags, void *state,
115  void *txv, const Signature *s,
116  const SigMatchCtx *ctx)
117 {
118  int32_t err_code;
119  int ret;
120  const DetectKrb5ErrCodeData *dd = (const DetectKrb5ErrCodeData *)ctx;
121 
122  SCEnter();
123 
124  ret = rs_krb5_tx_get_errcode(txv, &err_code);
125  if (ret != 0)
126  SCReturnInt(0);
127 
128  if (dd->err_code == err_code)
129  SCReturnInt(1);
130 
131  SCReturnInt(0);
132 }
133 
134 /**
135  * \brief This function is used to parse options passed via krb5_errcode: keyword
136  *
137  * \param krb5str Pointer to the user provided krb5_err_code options
138  *
139  * \retval krb5d pointer to DetectKrb5Data on success
140  * \retval NULL on failure
141  */
142 static DetectKrb5ErrCodeData *DetectKrb5ErrCodeParse (const char *krb5str)
143 {
144  DetectKrb5ErrCodeData *krb5d = NULL;
145  char arg1[4] = "";
146  int ret = 0, res = 0;
147  int ov[MAX_SUBSTRINGS];
148 
149  ret = DetectParsePcreExec(&parse_regex, krb5str, 0, 0, ov, MAX_SUBSTRINGS);
150  if (ret != 2) {
151  SCLogError(SC_ERR_PCRE_MATCH, "parse error, ret %" PRId32 "", ret);
152  goto error;
153  }
154 
155  res = pcre_copy_substring((char *) krb5str, ov, MAX_SUBSTRINGS, 1, arg1, sizeof(arg1));
156  if (res < 0) {
157  SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_copy_substring failed");
158  goto error;
159  }
160 
161  krb5d = SCMalloc(sizeof (DetectKrb5ErrCodeData));
162  if (unlikely(krb5d == NULL))
163  goto error;
164  if (StringParseInt32(&krb5d->err_code, 10, 0,
165  (const char *)arg1) < 0) {
166  goto error;
167  }
168  return krb5d;
169 
170 error:
171  if (krb5d)
172  SCFree(krb5d);
173  return NULL;
174 }
175 
176 /**
177  * \brief parse the options from the 'krb5_err_code' keyword in the rule into
178  * the Signature data structure.
179  *
180  * \param de_ctx pointer to the Detection Engine Context
181  * \param s pointer to the Current Signature
182  * \param krb5str pointer to the user provided options
183  *
184  * \retval 0 on Success
185  * \retval -1 on Failure
186  */
187 static int DetectKrb5ErrCodeSetup (DetectEngineCtx *de_ctx, Signature *s, const char *krb5str)
188 {
189  DetectKrb5ErrCodeData *krb5d = NULL;
190  SigMatch *sm = NULL;
191 
193  return -1;
194 
195  krb5d = DetectKrb5ErrCodeParse(krb5str);
196  if (krb5d == NULL)
197  goto error;
198 
199  sm = SigMatchAlloc();
200  if (sm == NULL)
201  goto error;
202 
204  sm->ctx = (void *)krb5d;
205 
206  SigMatchAppendSMToList(s, sm, g_krb5_err_code_list_id);
207 
208  return 0;
209 
210 error:
211  if (krb5d != NULL)
212  DetectKrb5ErrCodeFree(de_ctx, krb5d);
213  if (sm != NULL)
214  SCFree(sm);
215  return -1;
216 }
217 
218 /**
219  * \brief this function will free memory associated with DetectKrb5Data
220  *
221  * \param ptr pointer to DetectKrb5Data
222  */
223 static void DetectKrb5ErrCodeFree(DetectEngineCtx *de_ctx, void *ptr) {
225 
226  SCFree(krb5d);
227 }
228 
229 #ifdef UNITTESTS
230 /**
231  * \test description of the test
232  */
233 
234 static int DetectKrb5ErrCodeParseTest01 (void)
235 {
236  DetectKrb5ErrCodeData *krb5d = DetectKrb5ErrCodeParse("10");
237  FAIL_IF_NULL(krb5d);
238  FAIL_IF(!(krb5d->err_code == 10));
239  DetectKrb5ErrCodeFree(NULL, krb5d);
240  PASS;
241 }
242 
243 static int DetectKrb5ErrCodeSignatureTest01 (void)
244 {
247 
248  Signature *sig = DetectEngineAppendSig(de_ctx, "alert krb5 any any -> any any (krb5_err_code:10; sid:1; rev:1;)");
249  FAIL_IF_NULL(sig);
250 
252  PASS;
253 }
254 
255 /**
256  * \brief this function registers unit tests for DetectKrb5ErrCode
257  */
258 static void DetectKrb5ErrCodeRegisterTests(void)
259 {
260  UtRegisterTest("DetectKrb5ErrCodeParseTest01", DetectKrb5ErrCodeParseTest01);
261  UtRegisterTest("DetectKrb5ErrCodeSignatureTest01",
262  DetectKrb5ErrCodeSignatureTest01);
263 }
264 #endif /* UNITTESTS */
util-byte.h
SigTableElmt_::url
const char * url
Definition: detect.h:1214
DetectSignatureSetAppProto
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
Definition: detect-parse.c:1480
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:1213
SigTableElmt_::Free
void(* Free)(DetectEngineCtx *, void *)
Definition: detect.h:1201
SigTableElmt_::name
const char * name
Definition: detect.h:1211
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
DetectKrb5ErrCodeData_::err_code
int32_t err_code
Definition: detect-krb5-errcode.h:28
SCLogDebug
#define SCLogDebug(...)
Definition: util-debug.h:298
Flow_
Flow data structure.
Definition: flow.h:347
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:767
Krb5PrincipalNameDataArgs::txv
void * txv
Definition: detect-krb5-cname.c:43
StringParseInt32
int StringParseInt32(int32_t *res, int base, uint16_t len, const char *str)
Definition: util-byte.c:613
DetectEngineCtxFree
void DetectEngineCtxFree(DetectEngineCtx *)
Free a DetectEngineCtx::
Definition: detect-engine.c:2093
SigTableElmt_::AppLayerTxMatch
int(* AppLayerTxMatch)(DetectEngineThreadCtx *, Flow *, uint8_t flags, void *alstate, void *txv, const Signature *, const SigMatchCtx *)
Definition: detect.h:1182
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:329
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1196
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:1596
ALPROTO_KRB5
@ ALPROTO_KRB5
Definition: app-layer-protos.h:50
DetectKrb5ErrCodeData_
Definition: detect-krb5-errcode.h:27
detect-krb5-errcode.h
app-layer-krb5.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:1010
DetectKrb5ErrCodeRegister
void DetectKrb5ErrCodeRegister(void)
Registration function for krb5_err_code: keyword.
Definition: detect-krb5-errcode.c:65
res
PoolThreadReserved res
Definition: stream-tcp-private.h:0
DetectSetupParseRegexes
void DetectSetupParseRegexes(const char *parse_str, DetectParseRegex *detect_parse)
Definition: detect-parse.c:2493
SCEnter
#define SCEnter(...)
Definition: util-debug.h:300
ThreadVars_
Per thread variable structure.
Definition: threadvars.h:58
PARSE_REGEX
#define PARSE_REGEX
Regex for parsing our keyword options.
Definition: detect-krb5-errcode.c:39
SigMatch_::ctx
SigMatchCtx * ctx
Definition: detect.h:323
DetectParsePcreExec
int DetectParsePcreExec(DetectParseRegex *parse_regex, const char *str, int start_offset, int options, int *ovector, int ovector_size)
Definition: detect-parse.c:2423
SigTableElmt_::Match
int(* Match)(DetectEngineThreadCtx *, Packet *, const Signature *, const SigMatchCtx *)
Definition: detect.h:1179
SigMatchAlloc
SigMatch * SigMatchAlloc(void)
Definition: detect-parse.c:235
SigMatch_::type
uint8_t type
Definition: detect.h:321
SigMatchCtx_
Used to start a pointer to SigMatch context Should never be dereferenced without casting to something...
Definition: detect.h:315
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:2361
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:836
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
SCFree
#define SCFree(p)
Definition: util-mem.h:61
detect-parse.h
Signature_
Signature container.
Definition: detect.h:528
SigMatch_
a single match condition for a signature
Definition: detect.h:320
DETECT_AL_KRB5_ERRCODE
@ DETECT_AL_KRB5_ERRCODE
Definition: detect-engine-register.h:240
DetectEngineCtxInit
DetectEngineCtx * DetectEngineCtxInit(void)
Definition: detect-engine.c:2048
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:171
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:1203