suricata
detect-tag.c
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1 /* Copyright (C) 2007-2020 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 detect-tag.c
20  *
21  * \author Pablo Rincon <pablo.rincon.crespo@gmail.com>
22  * \author Victor Julien <victor@inliniac.net>
23  *
24  * Implements the tag keyword
25  *
26  */
27 
28 #include "suricata-common.h"
29 #include "detect.h"
30 #include "detect-parse.h"
31 #include "detect-tag.h"
32 #include "detect-engine-tag.h"
33 #include "detect-engine.h"
34 #include "detect-engine-state.h"
35 #include "app-layer-parser.h"
36 
37 #include "decode.h"
38 
39 #include "flow.h"
40 #include "flow-var.h"
41 #include "flow-util.h"
42 #include "stream-tcp-private.h"
43 
44 #include "util-time.h"
45 #include "util-byte.h"
46 #include "util-unittest.h"
47 #include "util-unittest-helper.h"
48 #include "util-debug.h"
49 #include "threads.h"
50 
51 SC_ATOMIC_EXTERN(unsigned int, num_tags);
52 
53 /* format: tag: <type>, <count>, <metric>, [direction]; */
54 #define PARSE_REGEX "^\\s*(host|session)\\s*(,\\s*(\\d+)\\s*,\\s*(packets|bytes|seconds)\\s*(,\\s*(src|dst))?\\s*)?$"
55 
56 static DetectParseRegex parse_regex;
57 
58 static int DetectTagMatch(DetectEngineThreadCtx *, Packet *,
59  const Signature *, const SigMatchCtx *);
60 static int DetectTagSetup(DetectEngineCtx *, Signature *, const char *);
61 #ifdef UNITTESTS
62 static void DetectTagRegisterTests(void);
63 #endif
64 void DetectTagDataFree(DetectEngineCtx *, void *);
65 
66 /**
67  * \brief Registration function for keyword tag
68  */
70 {
72  sigmatch_table[DETECT_TAG].Match = DetectTagMatch;
73  sigmatch_table[DETECT_TAG].Setup = DetectTagSetup;
75 #ifdef UNITTESTS
76  sigmatch_table[DETECT_TAG].RegisterTests = DetectTagRegisterTests;
77 #endif
79 
80  DetectSetupParseRegexes(PARSE_REGEX, &parse_regex);
81 }
82 
83 /**
84  * \brief This function is used to setup a tag for session/host
85  *
86  * \param t pointer to thread vars
87  * \param det_ctx pointer to the pattern matcher thread
88  * \param p pointer to the current packet
89  * \param m pointer to the sigmatch that we will cast into DetectTagData
90  *
91  * \retval 0 no match
92  * \retval 1 match
93  */
94 static int DetectTagMatch(DetectEngineThreadCtx *det_ctx, Packet *p,
95  const Signature *s, const SigMatchCtx *ctx)
96 {
97  const DetectTagData *td = (const DetectTagData *)ctx;
99  memset(&tde, 0, sizeof(DetectTagDataEntry));
100 
101  switch (td->type) {
103 #ifdef DEBUG
105 #endif
106 
107  tde.sid = s->id;
108  tde.gid = s->gid;
109  tde.last_ts = tde.first_ts = SCTIME_SECS(p->ts);
110  tde.metric = td->metric;
111  tde.count = td->count;
112  if (td->direction == DETECT_TAG_DIR_SRC)
114  else if (td->direction == DETECT_TAG_DIR_DST)
116 
117  SCLogDebug("Tagging Host with sid %"PRIu32":%"PRIu32"", s->id, s->gid);
118  TagHashAddTag(&tde, p);
119  break;
121  if (p->flow != NULL) {
122  SCLogDebug("Setting up tag for flow");
123  /* If it already exists it will be updated */
124  tde.sid = s->id;
125  tde.gid = s->gid;
126  tde.last_ts = tde.first_ts = SCTIME_SECS(p->ts);
127  tde.metric = td->metric;
128  tde.count = td->count;
129 
130  SCLogDebug("Adding to or updating flow; first_ts %u count %u",
131  tde.first_ts, tde.count);
132  TagFlowAdd(p, &tde);
133  } else {
134  SCLogDebug("No flow to append the session tag");
135  }
136  break;
137 #ifdef DEBUG
138  default:
139  SCLogDebug("unknown type of a tag keyword (not session nor host)");
140  BUG_ON(1);
141  break;
142 #endif
143  }
144 
145  return 1;
146 }
147 
148 /**
149  * \brief This function is used to parse tag options passed to tag keyword
150  *
151  * \param tagstr Pointer to the user provided tag options
152  *
153  * \retval td pointer to DetectTagData on success
154  * \retval NULL on failure
155  */
156 static DetectTagData *DetectTagParse(const char *tagstr)
157 {
158  DetectTagData td;
159  size_t pcre2_len;
160  const char *str_ptr = NULL;
161 
162  pcre2_match_data *match = NULL;
163  int ret = DetectParsePcreExec(&parse_regex, &match, tagstr, 0, 0);
164  if (ret < 1) {
165  SCLogError("parse error, ret %" PRId32 ", string %s", ret, tagstr);
166  goto error;
167  }
168 
169  int res = pcre2_substring_get_bynumber(match, 1, (PCRE2_UCHAR8 **)&str_ptr, &pcre2_len);
170  if (res < 0 || str_ptr == NULL) {
171  SCLogError("pcre2_substring_get_bynumber failed");
172  goto error;
173  }
174 
175  /* Type */
176  if (strcasecmp("session", str_ptr) == 0) {
178  } else if (strcasecmp("host", str_ptr) == 0) {
180  } else {
181  SCLogError("Invalid argument type. Must be session or host (%s)", tagstr);
182  goto error;
183  }
184  pcre2_substring_free((PCRE2_UCHAR *)str_ptr);
185  str_ptr = NULL;
186 
187  /* default tag is 256 packets from session or dst host */
191 
192  if (ret > 4) {
193  res = pcre2_substring_get_bynumber(match, 3, (PCRE2_UCHAR8 **)&str_ptr, &pcre2_len);
194  if (res < 0 || str_ptr == NULL) {
195  SCLogError("pcre2_substring_get_bynumber failed");
196  goto error;
197  }
198 
199  /* count */
200  if (StringParseUint32(&td.count, 10, strlen(str_ptr),
201  str_ptr) <= 0) {
202  SCLogError("Invalid argument for count. Must be a value in the range of 0 to %" PRIu32
203  " (%s)",
204  UINT32_MAX, tagstr);
205  goto error;
206  }
207 
208  pcre2_substring_free((PCRE2_UCHAR *)str_ptr);
209  str_ptr = NULL;
210 
211  res = pcre2_substring_get_bynumber(match, 4, (PCRE2_UCHAR8 **)&str_ptr, &pcre2_len);
212  if (res < 0 || str_ptr == NULL) {
213  SCLogError("pcre2_substring_get_bynumber failed");
214  goto error;
215  }
216 
217  /* metric */
218  if (strcasecmp("packets", str_ptr) == 0) {
222  /* TODO: load DETECT_TAG_MAX_PKTS from config */
223  } else if (strcasecmp("seconds", str_ptr) == 0) {
225  } else if (strcasecmp("bytes", str_ptr) == 0) {
227  } else {
228  SCLogError(
229  "Invalid argument metric. Must be one of \"seconds\", \"packets\" or \"bytes\" "
230  "(%s)",
231  tagstr);
232  goto error;
233  }
234 
235  pcre2_substring_free((PCRE2_UCHAR *)str_ptr);
236  str_ptr = NULL;
237 
238  /* if specified, overwrite it */
239  if (ret == 7) {
240  res = pcre2_substring_get_bynumber(match, 6, (PCRE2_UCHAR8 **)&str_ptr, &pcre2_len);
241  if (res < 0 || str_ptr == NULL) {
242  SCLogError("pcre2_substring_get_bynumber failed");
243  goto error;
244  }
245 
246  /* metric */
247  if (strcasecmp("src", str_ptr) == 0) {
249  } else if (strcasecmp("dst", str_ptr) == 0) {
251  } else {
252  SCLogError(
253  "Invalid argument direction. Must be one of \"src\" or \"dst\" (only valid "
254  "for tag host type, not sessions) (%s)",
255  tagstr);
256  goto error;
257  }
258 
259  if (td.type != DETECT_TAG_TYPE_HOST) {
260  SCLogWarning(
261  "Argument direction doesn't make sense for type \"session\" (%s [%" PRIu8
262  "])",
263  tagstr, td.type);
264  }
265 
266  pcre2_substring_free((PCRE2_UCHAR *)str_ptr);
267  str_ptr = NULL;
268  }
269  }
270 
271  DetectTagData *real_td = SCMalloc(sizeof(DetectTagData));
272  if (unlikely(real_td == NULL)) {
273  SCLogError("Error allocating memory");
274  goto error;
275  }
276 
277  memcpy(real_td, &td, sizeof(DetectTagData));
278  pcre2_match_data_free(match);
279  return real_td;
280 
281 error:
282  if (match) {
283  pcre2_match_data_free(match);
284  }
285  if (str_ptr != NULL)
286  pcre2_substring_free((PCRE2_UCHAR *)str_ptr);
287  return NULL;
288 }
289 
290 /**
291  * \brief this function is used to add the parsed tag data into the current signature
292  *
293  * \param de_ctx pointer to the Detection Engine Context
294  * \param s pointer to the Current Signature
295  * \param tagstr pointer to the user provided tag options
296  *
297  * \retval 0 on Success
298  * \retval -1 on Failure
299  */
300 int DetectTagSetup(DetectEngineCtx *de_ctx, Signature *s, const char *tagstr)
301 {
302  DetectTagData *td = DetectTagParse(tagstr);
303  if (td == NULL)
304  return -1;
305 
306  /* Append it to the list of tags */
308  NULL) {
310  return -1;
311  }
312  return 0;
313 }
314 
315 /** \internal
316  * \brief this function will free memory associated with
317  * DetectTagDataEntry
318  *
319  * \param td pointer to DetectTagDataEntry
320  */
321 static void DetectTagDataEntryFree(void *ptr)
322 {
323  if (ptr != NULL) {
325  SCFree(dte);
326  }
327 }
328 
329 
330 /**
331  * \brief this function will free all the entries of a list
332  * DetectTagDataEntry
333  *
334  * \param td pointer to DetectTagDataEntryList
335  */
336 void DetectTagDataListFree(void *ptr)
337 {
338  if (ptr != NULL) {
339  DetectTagDataEntry *entry = ptr;
340 
341  while (entry != NULL) {
342  DetectTagDataEntry *next_entry = entry->next;
343  DetectTagDataEntryFree(entry);
344  (void) SC_ATOMIC_SUB(num_tags, 1);
345  entry = next_entry;
346  }
347  }
348 }
349 
350 /**
351  * \brief this function will free memory associated with DetectTagData
352  *
353  * \param td pointer to DetectTagData
354  */
356 {
357  DetectTagData *td = (DetectTagData *)ptr;
358  SCFree(td);
359 }
360 
361 #ifdef UNITTESTS
362 
363 /**
364  * \test DetectTagTestParse01 is a test to make sure that we return "something"
365  * when given valid tag opt
366  */
367 static int DetectTagTestParse01(void)
368 {
369  int result = 0;
370  DetectTagData *td = NULL;
371  td = DetectTagParse("session, 123, packets");
372  if (td != NULL && td->type == DETECT_TAG_TYPE_SESSION
373  && td->count == 123
374  && td->metric == DETECT_TAG_METRIC_PACKET) {
375  DetectTagDataFree(NULL, td);
376  result = 1;
377  }
378 
379  return result;
380 }
381 
382 /**
383  * \test DetectTagTestParse02 is a test to check that we parse tag correctly
384  */
385 static int DetectTagTestParse02(void)
386 {
387  int result = 0;
388  DetectTagData *td = NULL;
389  td = DetectTagParse("host, 200, bytes, src");
390  if (td != NULL && td->type == DETECT_TAG_TYPE_HOST
391  && td->count == 200
393  && td->direction == DETECT_TAG_DIR_SRC) {
394  result = 1;
395  DetectTagDataFree(NULL, td);
396  }
397 
398  return result;
399 }
400 
401 /**
402  * \test DetectTagTestParse03 is a test for setting the stateless tag opt
403  */
404 static int DetectTagTestParse03(void)
405 {
406  int result = 0;
407  DetectTagData *td = NULL;
408  td = DetectTagParse("host, 200, bytes, dst");
409  if (td != NULL && td->type == DETECT_TAG_TYPE_HOST
410  && td->count == 200
412  && td->direction == DETECT_TAG_DIR_DST) {
413  result = 1;
414  DetectTagDataFree(NULL, td);
415  }
416 
417  return result;
418 }
419 
420 /**
421  * \test DetectTagTestParse04 is a test for default opts
422  */
423 static int DetectTagTestParse04(void)
424 {
425  int result = 0;
426  DetectTagData *td = NULL;
427  td = DetectTagParse("session");
428  if (td != NULL && td->type == DETECT_TAG_TYPE_SESSION
429  && td->count == DETECT_TAG_MAX_PKTS
430  && td->metric == DETECT_TAG_METRIC_PACKET) {
431  result = 1;
432  DetectTagDataFree(NULL, td);
433  }
434 
435  return result;
436 }
437 
438 /**
439  * \test DetectTagTestParse05 is a test for default opts
440  */
441 static int DetectTagTestParse05(void)
442 {
443  int result = 0;
444  DetectTagData *td = NULL;
445  td = DetectTagParse("host");
446  if (td != NULL && td->type == DETECT_TAG_TYPE_HOST
447  && td->count == DETECT_TAG_MAX_PKTS
449  && td->direction == DETECT_TAG_DIR_DST) {
450  result = 1;
451  DetectTagDataFree(NULL, td);
452  }
453 
454  return result;
455 }
456 
457 /**
458  * \brief this function registers unit tests for DetectTag
459  */
460 void DetectTagRegisterTests(void)
461 {
462  UtRegisterTest("DetectTagTestParse01", DetectTagTestParse01);
463  UtRegisterTest("DetectTagTestParse02", DetectTagTestParse02);
464  UtRegisterTest("DetectTagTestParse03", DetectTagTestParse03);
465  UtRegisterTest("DetectTagTestParse04", DetectTagTestParse04);
466  UtRegisterTest("DetectTagTestParse05", DetectTagTestParse05);
467 
469 }
470 #endif /* UNITTESTS */
util-byte.h
detect-engine.h
SigTableElmt_::Free
void(* Free)(DetectEngineCtx *, void *)
Definition: detect.h:1283
flow-util.h
DetectParseRegex
Definition: detect-parse.h:62
DetectTagDataEntry_::last_ts
uint32_t last_ts
Definition: detect-tag.h:83
SigTableElmt_::name
const char * name
Definition: detect.h:1293
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
DETECT_TAG_METRIC_BYTES
@ DETECT_TAG_METRIC_BYTES
Definition: detect-tag.h:57
SCLogDebug
#define SCLogDebug(...)
Definition: util-debug.h:269
DetectTagDataEntry_
Definition: detect-tag.h:69
threads.h
DetectTagDataEntry_::sid
uint32_t sid
Definition: detect-tag.h:76
SigTableElmt_::flags
uint16_t flags
Definition: detect.h:1287
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:836
DetectTagDataListFree
void DetectTagDataListFree(void *ptr)
this function will free all the entries of a list DetectTagDataEntry
Definition: detect-tag.c:336
TAG_ENTRY_FLAG_DIR_SRC
#define TAG_ENTRY_FLAG_DIR_SRC
Definition: detect-tag.h:91
DetectParsePcreExec
int DetectParsePcreExec(DetectParseRegex *parse_regex, pcre2_match_data **match, const char *str, int start_offset, int options)
Definition: detect-parse.c:2674
DetectTagDataEntry_::metric
uint8_t metric
Definition: detect-tag.h:71
detect-tag.h
DetectTagData_::direction
uint8_t direction
Definition: detect-tag.h:63
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1278
util-unittest.h
DETECT_TAG_DIR_DST
@ DETECT_TAG_DIR_DST
Definition: detect-tag.h:51
DetectTagDataEntry_::flags
uint8_t flags
Definition: detect-tag.h:70
util-unittest-helper.h
DetectTagDataEntry_::gid
uint32_t gid
Definition: detect-tag.h:77
Signature_::gid
uint32_t gid
Definition: detect.h:629
DetectTagDataEntry_::count
uint32_t count
Definition: detect-tag.h:75
DETECT_TAG_METRIC_SECONDS
@ DETECT_TAG_METRIC_SECONDS
Definition: detect-tag.h:56
decode.h
util-debug.h
de_ctx
DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:17
TAG_ENTRY_FLAG_DIR_DST
#define TAG_ENTRY_FLAG_DIR_DST
Definition: detect-tag.h:92
DetectEngineThreadCtx_
Definition: detect.h:1092
Packet_::ts
SCTime_t ts
Definition: decode.h:485
DetectTagDataEntry_::first_ts
uint32_t first_ts
Definition: detect-tag.h:82
DetectSetupParseRegexes
void DetectSetupParseRegexes(const char *parse_str, DetectParseRegex *detect_parse)
Definition: detect-parse.c:2791
detect.h
StringParseUint32
int StringParseUint32(uint32_t *res, int base, size_t len, const char *str)
Definition: util-byte.c:313
util-time.h
SCLogWarning
#define SCLogWarning(...)
Macro used to log WARNING messages.
Definition: util-debug.h:249
app-layer-parser.h
BUG_ON
#define BUG_ON(x)
Definition: suricata-common.h:300
detect-engine-tag.h
SC_ATOMIC_SUB
#define SC_ATOMIC_SUB(name, val)
sub a value from our atomic variable
Definition: util-atomic.h:341
SC_ATOMIC_EXTERN
SC_ATOMIC_EXTERN(unsigned int, num_tags)
DETECT_TAG_METRIC_PACKET
@ DETECT_TAG_METRIC_PACKET
Definition: detect-tag.h:55
Packet_
Definition: decode.h:437
stream-tcp-private.h
detect-engine-state.h
Data structures and function prototypes for keeping state for the detection engine.
SigTableElmt_::Match
int(* Match)(DetectEngineThreadCtx *, Packet *, const Signature *, const SigMatchCtx *)
Definition: detect.h:1261
SigMatchCtx_
Used to start a pointer to SigMatch context Should never be dereferenced without casting to something...
Definition: detect.h:342
DetectTagRegister
void DetectTagRegister(void)
Registration function for keyword tag.
Definition: detect-tag.c:69
DETECT_TAG_MAX_PKTS
#define DETECT_TAG_MAX_PKTS
Definition: detect-tag.h:40
Packet_::flow
struct Flow_ * flow
Definition: decode.h:476
suricata-common.h
sigmatch_table
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect-parse.c:127
DETECT_TAG_TYPE_SESSION
@ DETECT_TAG_TYPE_SESSION
Definition: detect-tag.h:44
SCTIME_SECS
#define SCTIME_SECS(t)
Definition: util-time.h:57
DETECT_TAG
@ DETECT_TAG
Definition: detect-engine-register.h:60
DETECT_SM_LIST_TMATCH
@ DETECT_SM_LIST_TMATCH
Definition: detect.h:123
SCMalloc
#define SCMalloc(sz)
Definition: util-mem.h:47
DetectTagData_::count
uint32_t count
Definition: detect-tag.h:64
DetectEngineTagRegisterTests
void DetectEngineTagRegisterTests(void)
this function registers unit tests for DetectTag
Definition: detect-engine-tag.c:1398
DETECT_TAG_DIR_SRC
@ DETECT_TAG_DIR_SRC
Definition: detect-tag.h:50
SCLogError
#define SCLogError(...)
Macro used to log ERROR messages.
Definition: util-debug.h:261
SCFree
#define SCFree(p)
Definition: util-mem.h:61
Signature_::id
uint32_t id
Definition: detect.h:628
TagFlowAdd
int TagFlowAdd(Packet *p, DetectTagDataEntry *tde)
This function is used to add a tag to a session (type session) or update it if it's already installed...
Definition: detect-engine-tag.c:123
detect-parse.h
Signature_
Signature container.
Definition: detect.h:593
TagHashAddTag
int TagHashAddTag(DetectTagDataEntry *tde, Packet *p)
Add a tag entry for a host. If it already exist, update it.
Definition: detect-engine-tag.c:180
DetectTagDataEntry_::next
struct DetectTagDataEntry_ * next
Definition: detect-tag.h:87
DetectTagData_
Definition: detect-tag.h:61
DetectTagData_::type
uint8_t type
Definition: detect-tag.h:62
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:447
PARSE_REGEX
#define PARSE_REGEX
Definition: detect-tag.c:54
DetectTagData_::metric
uint8_t metric
Definition: detect-tag.h:65
DETECT_TAG_TYPE_HOST
@ DETECT_TAG_TYPE_HOST
Definition: detect-tag.h:45
flow.h
flow-var.h
SIGMATCH_IPONLY_COMPAT
#define SIGMATCH_IPONLY_COMPAT
Definition: detect.h:1475
DetectTagDataFree
void DetectTagDataFree(DetectEngineCtx *, void *)
this function will free memory associated with DetectTagData
Definition: detect-tag.c:355
SigTableElmt_::RegisterTests
void(* RegisterTests)(void)
Definition: detect.h:1285