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 "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 DetectKrb5ErrCodeRegister below */
42 static int DetectKrb5ErrCodeMatch (DetectEngineThreadCtx *, Flow *,
43  uint8_t, void *, void *, const Signature *,
44  const SigMatchCtx *);
45 static int DetectKrb5ErrCodeSetup (DetectEngineCtx *, Signature *, const char *);
46 static void DetectKrb5ErrCodeFree (DetectEngineCtx *, void *);
47 #ifdef UNITTESTS
48 static void DetectKrb5ErrCodeRegisterTests (void);
49 #endif
50 
51 static int g_krb5_err_code_list_id = 0;
52 
53 /**
54  * \brief Registration function for krb5_err_code: keyword
55  *
56  * This function is called once in the 'lifetime' of the engine.
57  */
59 {
60  sigmatch_table[DETECT_AL_KRB5_ERRCODE].name = "krb5_err_code";
61  sigmatch_table[DETECT_AL_KRB5_ERRCODE].desc = "match Kerberos 5 error code";
62  sigmatch_table[DETECT_AL_KRB5_ERRCODE].url = "/rules/kerberos-keywords.html#krb5-err-code";
64  sigmatch_table[DETECT_AL_KRB5_ERRCODE].AppLayerTxMatch = DetectKrb5ErrCodeMatch;
65  sigmatch_table[DETECT_AL_KRB5_ERRCODE].Setup = DetectKrb5ErrCodeSetup;
66  sigmatch_table[DETECT_AL_KRB5_ERRCODE].Free = DetectKrb5ErrCodeFree;
67 #ifdef UNITTESTS
68  sigmatch_table[DETECT_AL_KRB5_ERRCODE].RegisterTests = DetectKrb5ErrCodeRegisterTests;
69 #endif
70 
73 
76 
77  /* set up the PCRE for keyword parsing */
78  DetectSetupParseRegexes(PARSE_REGEX, &parse_regex);
79 
80  g_krb5_err_code_list_id = DetectBufferTypeRegister("krb5_err_code");
81  SCLogDebug("g_krb5_err_code_list_id %d", g_krb5_err_code_list_id);
82 }
83 
84 /**
85  * \brief This function is used to match KRB5 rule option on a packet
86  *
87  * \param t pointer to thread vars
88  * \param det_ctx pointer to the pattern matcher thread
89  * \param p pointer to the current packet
90  * \param m pointer to the sigmatch with context that we will cast into DetectKrb5Data
91  *
92  * \retval 0 no match
93  * \retval 1 match
94  */
95 static int DetectKrb5ErrCodeMatch (DetectEngineThreadCtx *det_ctx,
96  Flow *f, uint8_t flags, void *state,
97  void *txv, const Signature *s,
98  const SigMatchCtx *ctx)
99 {
100  int32_t err_code;
101  int ret;
102  const DetectKrb5ErrCodeData *dd = (const DetectKrb5ErrCodeData *)ctx;
103 
104  SCEnter();
105 
106  ret = rs_krb5_tx_get_errcode(txv, &err_code);
107  if (ret != 0)
108  SCReturnInt(0);
109 
110  if (dd->err_code == err_code)
111  SCReturnInt(1);
112 
113  SCReturnInt(0);
114 }
115 
116 /**
117  * \brief This function is used to parse options passed via krb5_errcode: keyword
118  *
119  * \param krb5str Pointer to the user provided krb5_err_code options
120  *
121  * \retval krb5d pointer to DetectKrb5Data on success
122  * \retval NULL on failure
123  */
124 static DetectKrb5ErrCodeData *DetectKrb5ErrCodeParse (const char *krb5str)
125 {
126  DetectKrb5ErrCodeData *krb5d = NULL;
127  char arg1[4] = "";
128  int res = 0;
129  size_t pcre2len;
130 
131  pcre2_match_data *match = NULL;
132  int ret = DetectParsePcreExec(&parse_regex, &match, krb5str, 0, 0);
133  if (ret != 2) {
134  SCLogError("parse error, ret %" PRId32 "", ret);
135  goto error;
136  }
137 
138  pcre2len = sizeof(arg1);
139  res = pcre2_substring_copy_bynumber(match, 1, (PCRE2_UCHAR8 *)arg1, &pcre2len);
140  if (res < 0) {
141  SCLogError("pcre2_substring_copy_bynumber failed");
142  goto error;
143  }
144 
145  krb5d = SCMalloc(sizeof (DetectKrb5ErrCodeData));
146  if (unlikely(krb5d == NULL))
147  goto error;
148  if (StringParseInt32(&krb5d->err_code, 10, 0,
149  (const char *)arg1) < 0) {
150  goto error;
151  }
152  pcre2_match_data_free(match);
153  return krb5d;
154 
155 error:
156  if (match) {
157  pcre2_match_data_free(match);
158  }
159  if (krb5d)
160  SCFree(krb5d);
161  return NULL;
162 }
163 
164 /**
165  * \brief parse the options from the 'krb5_err_code' keyword in the rule into
166  * the Signature data structure.
167  *
168  * \param de_ctx pointer to the Detection Engine Context
169  * \param s pointer to the Current Signature
170  * \param krb5str pointer to the user provided options
171  *
172  * \retval 0 on Success
173  * \retval -1 on Failure
174  */
175 static int DetectKrb5ErrCodeSetup (DetectEngineCtx *de_ctx, Signature *s, const char *krb5str)
176 {
177  DetectKrb5ErrCodeData *krb5d = NULL;
178 
180  return -1;
181 
182  krb5d = DetectKrb5ErrCodeParse(krb5str);
183  if (krb5d == NULL)
184  goto error;
185 
187  g_krb5_err_code_list_id) == NULL) {
188  goto error;
189  }
190 
191  return 0;
192 
193 error:
194  if (krb5d != NULL)
195  DetectKrb5ErrCodeFree(de_ctx, krb5d);
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 DetectKrb5ErrCodeFree(DetectEngineCtx *de_ctx, void *ptr) {
206 
207  SCFree(krb5d);
208 }
209 
210 #ifdef UNITTESTS
211 /**
212  * \test description of the test
213  */
214 
215 static int DetectKrb5ErrCodeParseTest01 (void)
216 {
217  DetectKrb5ErrCodeData *krb5d = DetectKrb5ErrCodeParse("10");
218  FAIL_IF_NULL(krb5d);
219  FAIL_IF(!(krb5d->err_code == 10));
220  DetectKrb5ErrCodeFree(NULL, krb5d);
221  PASS;
222 }
223 
224 static int DetectKrb5ErrCodeSignatureTest01 (void)
225 {
228 
229  Signature *sig = DetectEngineAppendSig(de_ctx, "alert krb5 any any -> any any (krb5_err_code:10; sid:1; rev:1;)");
230  FAIL_IF_NULL(sig);
231 
233  PASS;
234 }
235 
236 /**
237  * \brief this function registers unit tests for DetectKrb5ErrCode
238  */
239 static void DetectKrb5ErrCodeRegisterTests(void)
240 {
241  UtRegisterTest("DetectKrb5ErrCodeParseTest01", DetectKrb5ErrCodeParseTest01);
242  UtRegisterTest("DetectKrb5ErrCodeSignatureTest01",
243  DetectKrb5ErrCodeSignatureTest01);
244 }
245 #endif /* UNITTESTS */
util-byte.h
SigTableElmt_::url
const char * url
Definition: detect.h:1307
DetectSignatureSetAppProto
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
Definition: detect-parse.c:1737
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:1306
sigmatch_table
SigTableElmt * sigmatch_table
Definition: detect-parse.c:127
SigTableElmt_::Free
void(* Free)(DetectEngineCtx *, void *)
Definition: detect.h:1294
DetectParseRegex
Definition: detect-parse.h:62
SigTableElmt_::name
const char * name
Definition: detect.h:1304
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:269
Flow_
Flow data structure.
Definition: flow.h:356
ctx
struct Thresholds ctx
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:841
DetectEngineCtxFree
void DetectEngineCtxFree(DetectEngineCtx *)
Free a DetectEngineCtx::
Definition: detect-engine.c:2599
SigTableElmt_::AppLayerTxMatch
int(* AppLayerTxMatch)(DetectEngineThreadCtx *, Flow *, uint8_t flags, void *alstate, void *txv, const Signature *, const SigMatchCtx *)
Definition: detect.h:1275
rust.h
DetectParsePcreExec
int DetectParsePcreExec(DetectParseRegex *parse_regex, pcre2_match_data **match, const char *str, int start_offset, int options)
Definition: detect-parse.c:2641
StringParseInt32
int StringParseInt32(int32_t *res, int base, size_t len, const char *str)
Definition: util-byte.c:622
DetectEngineAppendSig
Signature * DetectEngineAppendSig(DetectEngineCtx *, const char *)
Parse and append a Signature into the Detection Engine Context signature list.
Definition: detect-parse.c:2587
SIG_FLAG_TOCLIENT
#define SIG_FLAG_TOCLIENT
Definition: detect.h:268
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1289
util-unittest.h
ALPROTO_KRB5
@ ALPROTO_KRB5
Definition: app-layer-protos.h:50
DetectKrb5ErrCodeData_
Definition: detect-krb5-errcode.h:27
detect-krb5-errcode.h
SIG_FLAG_TOSERVER
#define SIG_FLAG_TOSERVER
Definition: detect.h:267
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:1093
DetectKrb5ErrCodeRegister
void DetectKrb5ErrCodeRegister(void)
Registration function for krb5_err_code: keyword.
Definition: detect-krb5-errcode.c:58
DetectSetupParseRegexes
void DetectSetupParseRegexes(const char *parse_str, DetectParseRegex *detect_parse)
Definition: detect-parse.c:2767
SCEnter
#define SCEnter(...)
Definition: util-debug.h:271
PARSE_REGEX
#define PARSE_REGEX
Regex for parsing our keyword options.
Definition: detect-krb5-errcode.c:38
SigTableElmt_::Match
int(* Match)(DetectEngineThreadCtx *, Packet *, const Signature *, const SigMatchCtx *)
Definition: detect.h:1272
SigMatchCtx_
Used to start a pointer to SigMatch context Should never be dereferenced without casting to something...
Definition: detect.h:344
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:1029
flags
uint8_t flags
Definition: decode-gre.h:0
suricata-common.h
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:2099
SCMalloc
#define SCMalloc(sz)
Definition: util-mem.h:47
SCLogError
#define SCLogError(...)
Macro used to log ERROR messages.
Definition: util-debug.h:261
SCFree
#define SCFree(p)
Definition: util-mem.h:61
detect-parse.h
Signature_
Signature container.
Definition: detect.h:601
DETECT_AL_KRB5_ERRCODE
@ DETECT_AL_KRB5_ERRCODE
Definition: detect-engine-register.h:270
DetectEngineCtxInit
DetectEngineCtx * DetectEngineCtxInit(void)
Definition: detect-engine.c:2560
DetectAppLayerInspectEngineRegister
void DetectAppLayerInspectEngineRegister(const char *name, AppProto alproto, uint32_t dir, int progress, InspectEngineFuncPtr Callback, InspectionBufferGetDataPtr GetData)
Registers an app inspection engine.
Definition: detect-engine.c:240
SigMatchAppendSMToList
SigMatch * SigMatchAppendSMToList(DetectEngineCtx *de_ctx, Signature *s, uint16_t type, SigMatchCtx *ctx, const int list)
Append a SigMatch to the list type.
Definition: detect-parse.c:436
SCReturnInt
#define SCReturnInt(x)
Definition: util-debug.h:275
SigTableElmt_::RegisterTests
void(* RegisterTests)(void)
Definition: detect.h:1296