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 g_krb5_err_code_list_id = 0;
53 
54 /**
55  * \brief Registration function for krb5_err_code: keyword
56  *
57  * This function is called once in the 'lifetime' of the engine.
58  */
60 {
61  sigmatch_table[DETECT_AL_KRB5_ERRCODE].name = "krb5_err_code";
62  sigmatch_table[DETECT_AL_KRB5_ERRCODE].desc = "match Kerberos 5 error code";
63  sigmatch_table[DETECT_AL_KRB5_ERRCODE].url = "/rules/kerberos-keywords.html#krb5-err-code";
65  sigmatch_table[DETECT_AL_KRB5_ERRCODE].AppLayerTxMatch = DetectKrb5ErrCodeMatch;
66  sigmatch_table[DETECT_AL_KRB5_ERRCODE].Setup = DetectKrb5ErrCodeSetup;
67  sigmatch_table[DETECT_AL_KRB5_ERRCODE].Free = DetectKrb5ErrCodeFree;
68 #ifdef UNITTESTS
69  sigmatch_table[DETECT_AL_KRB5_ERRCODE].RegisterTests = DetectKrb5ErrCodeRegisterTests;
70 #endif
71 
74 
77 
78  /* set up the PCRE for keyword parsing */
79  DetectSetupParseRegexes(PARSE_REGEX, &parse_regex);
80 
81  g_krb5_err_code_list_id = DetectBufferTypeRegister("krb5_err_code");
82  SCLogDebug("g_krb5_err_code_list_id %d", g_krb5_err_code_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 DetectKrb5ErrCodeMatch (DetectEngineThreadCtx *det_ctx,
97  Flow *f, uint8_t flags, void *state,
98  void *txv, const Signature *s,
99  const SigMatchCtx *ctx)
100 {
101  int32_t err_code;
102  int ret;
103  const DetectKrb5ErrCodeData *dd = (const DetectKrb5ErrCodeData *)ctx;
104 
105  SCEnter();
106 
107  ret = rs_krb5_tx_get_errcode(txv, &err_code);
108  if (ret != 0)
109  SCReturnInt(0);
110 
111  if (dd->err_code == err_code)
112  SCReturnInt(1);
113 
114  SCReturnInt(0);
115 }
116 
117 /**
118  * \brief This function is used to parse options passed via krb5_errcode: keyword
119  *
120  * \param krb5str Pointer to the user provided krb5_err_code options
121  *
122  * \retval krb5d pointer to DetectKrb5Data on success
123  * \retval NULL on failure
124  */
125 static DetectKrb5ErrCodeData *DetectKrb5ErrCodeParse (const char *krb5str)
126 {
127  DetectKrb5ErrCodeData *krb5d = NULL;
128  char arg1[4] = "";
129  int res = 0;
130  size_t pcre2len;
131 
132  pcre2_match_data *match = NULL;
133  int ret = DetectParsePcreExec(&parse_regex, &match, krb5str, 0, 0);
134  if (ret != 2) {
135  SCLogError("parse error, ret %" PRId32 "", ret);
136  goto error;
137  }
138 
139  pcre2len = sizeof(arg1);
140  res = pcre2_substring_copy_bynumber(match, 1, (PCRE2_UCHAR8 *)arg1, &pcre2len);
141  if (res < 0) {
142  SCLogError("pcre2_substring_copy_bynumber failed");
143  goto error;
144  }
145 
146  krb5d = SCMalloc(sizeof (DetectKrb5ErrCodeData));
147  if (unlikely(krb5d == NULL))
148  goto error;
149  if (StringParseInt32(&krb5d->err_code, 10, 0,
150  (const char *)arg1) < 0) {
151  goto error;
152  }
153  pcre2_match_data_free(match);
154  return krb5d;
155 
156 error:
157  if (match) {
158  pcre2_match_data_free(match);
159  }
160  if (krb5d)
161  SCFree(krb5d);
162  return NULL;
163 }
164 
165 /**
166  * \brief parse the options from the 'krb5_err_code' keyword in the rule into
167  * the Signature data structure.
168  *
169  * \param de_ctx pointer to the Detection Engine Context
170  * \param s pointer to the Current Signature
171  * \param krb5str pointer to the user provided options
172  *
173  * \retval 0 on Success
174  * \retval -1 on Failure
175  */
176 static int DetectKrb5ErrCodeSetup (DetectEngineCtx *de_ctx, Signature *s, const char *krb5str)
177 {
178  DetectKrb5ErrCodeData *krb5d = NULL;
179  SigMatch *sm = NULL;
180 
182  return -1;
183 
184  krb5d = DetectKrb5ErrCodeParse(krb5str);
185  if (krb5d == NULL)
186  goto error;
187 
188  sm = SigMatchAlloc();
189  if (sm == NULL)
190  goto error;
191 
193  sm->ctx = (void *)krb5d;
194 
195  SigMatchAppendSMToList(s, sm, g_krb5_err_code_list_id);
196 
197  return 0;
198 
199 error:
200  if (krb5d != NULL)
201  DetectKrb5ErrCodeFree(de_ctx, krb5d);
202  if (sm != NULL)
203  SCFree(sm);
204  return -1;
205 }
206 
207 /**
208  * \brief this function will free memory associated with DetectKrb5Data
209  *
210  * \param ptr pointer to DetectKrb5Data
211  */
212 static void DetectKrb5ErrCodeFree(DetectEngineCtx *de_ctx, void *ptr) {
214 
215  SCFree(krb5d);
216 }
217 
218 #ifdef UNITTESTS
219 /**
220  * \test description of the test
221  */
222 
223 static int DetectKrb5ErrCodeParseTest01 (void)
224 {
225  DetectKrb5ErrCodeData *krb5d = DetectKrb5ErrCodeParse("10");
226  FAIL_IF_NULL(krb5d);
227  FAIL_IF(!(krb5d->err_code == 10));
228  DetectKrb5ErrCodeFree(NULL, krb5d);
229  PASS;
230 }
231 
232 static int DetectKrb5ErrCodeSignatureTest01 (void)
233 {
236 
237  Signature *sig = DetectEngineAppendSig(de_ctx, "alert krb5 any any -> any any (krb5_err_code:10; sid:1; rev:1;)");
238  FAIL_IF_NULL(sig);
239 
241  PASS;
242 }
243 
244 /**
245  * \brief this function registers unit tests for DetectKrb5ErrCode
246  */
247 static void DetectKrb5ErrCodeRegisterTests(void)
248 {
249  UtRegisterTest("DetectKrb5ErrCodeParseTest01", DetectKrb5ErrCodeParseTest01);
250  UtRegisterTest("DetectKrb5ErrCodeSignatureTest01",
251  DetectKrb5ErrCodeSignatureTest01);
252 }
253 #endif /* UNITTESTS */
util-byte.h
SigTableElmt_::url
const char * url
Definition: detect.h:1287
DetectSignatureSetAppProto
int DetectSignatureSetAppProto(Signature *s, AppProto alproto)
Definition: detect-parse.c:1703
detect-engine.h
FAIL_IF_NULL
#define FAIL_IF_NULL(expr)
Fail a test if expression evaluates to NULL.
Definition: util-unittest.h:89
SigMatchAppendSMToList
void SigMatchAppendSMToList(Signature *s, SigMatch *new, const int list)
Append a SigMatch to the list type.
Definition: detect-parse.c:437
SigTableElmt_::desc
const char * desc
Definition: detect.h:1286
SigTableElmt_::Free
void(* Free)(DetectEngineCtx *, void *)
Definition: detect.h:1274
DetectParseRegex
Definition: detect-parse.h:62
SigTableElmt_::name
const char * name
Definition: detect.h:1284
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:347
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:826
Krb5PrincipalNameDataArgs::txv
void * txv
Definition: detect-krb5-cname.c:44
DetectEngineCtxFree
void DetectEngineCtxFree(DetectEngineCtx *)
Free a DetectEngineCtx::
Definition: detect-engine.c:2592
SigTableElmt_::AppLayerTxMatch
int(* AppLayerTxMatch)(DetectEngineThreadCtx *, Flow *, uint8_t flags, void *alstate, void *txv, const Signature *, const SigMatchCtx *)
Definition: detect.h:1255
rust.h
DetectParsePcreExec
int DetectParsePcreExec(DetectParseRegex *parse_regex, pcre2_match_data **match, const char *str, int start_offset, int options)
Definition: detect-parse.c:2623
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:2569
SIG_FLAG_TOCLIENT
#define SIG_FLAG_TOCLIENT
Definition: detect.h:256
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1269
util-unittest.h
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:255
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:1074
DetectKrb5ErrCodeRegister
void DetectKrb5ErrCodeRegister(void)
Registration function for krb5_err_code: keyword.
Definition: detect-krb5-errcode.c:59
DetectSetupParseRegexes
void DetectSetupParseRegexes(const char *parse_str, DetectParseRegex *detect_parse)
Definition: detect-parse.c:2747
SCEnter
#define SCEnter(...)
Definition: util-debug.h:271
PARSE_REGEX
#define PARSE_REGEX
Regex for parsing our keyword options.
Definition: detect-krb5-errcode.c:39
SigMatch_::ctx
SigMatchCtx * ctx
Definition: detect.h:343
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:216
SigTableElmt_::Match
int(* Match)(DetectEngineThreadCtx *, Packet *, const Signature *, const SigMatchCtx *)
Definition: detect.h:1252
SigMatchAlloc
SigMatch * SigMatchAlloc(void)
Definition: detect-parse.c:322
SigMatchCtx_
Used to start a pointer to SigMatch context Should never be dereferenced without casting to something...
Definition: detect.h:335
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:1060
flags
uint8_t flags
Definition: decode-gre.h:0
suricata-common.h
SigMatch_::type
uint16_t type
Definition: detect.h:341
sigmatch_table
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect-parse.c:129
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:2122
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:581
SigMatch_
a single match condition for a signature
Definition: detect.h:340
DETECT_AL_KRB5_ERRCODE
@ DETECT_AL_KRB5_ERRCODE
Definition: detect-engine-register.h:254
DetectEngineCtxInit
DetectEngineCtx * DetectEngineCtxInit(void)
Definition: detect-engine.c:2553
SCReturnInt
#define SCReturnInt(x)
Definition: util-debug.h:275
SigTableElmt_::RegisterTests
void(* RegisterTests)(void)
Definition: detect.h:1276