suricata
detect-datarep.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 Victor Julien <victor@inliniac.net>
22  *
23  * Implements the datarep keyword
24  */
25 
26 #include "suricata-common.h"
27 #include "decode.h"
28 #include "detect.h"
29 #include "threads.h"
30 #include "datasets.h"
31 #include "detect-datarep.h"
32 
33 #include "detect-parse.h"
34 #include "detect-engine.h"
35 #include "detect-engine-mpm.h"
36 #include "detect-engine-state.h"
37 
38 #include "util-byte.h"
39 #include "util-debug.h"
40 #include "util-print.h"
41 #include "util-misc.h"
42 #include "util-path.h"
43 
44 #define PARSE_REGEX "([a-z]+)(?:,\\s*([\\-_A-z0-9\\s\\.]+)){1,4}"
45 static DetectParseRegex parse_regex;
46 
48  const Signature *, const SigMatchCtx *);
49 static int DetectDatarepSetup (DetectEngineCtx *, Signature *, const char *);
50 void DetectDatarepFree (DetectEngineCtx *, void *);
51 
53 {
54  sigmatch_table[DETECT_DATAREP].name = "datarep";
55  sigmatch_table[DETECT_DATAREP].desc = "operate on datasets (experimental)";
56  sigmatch_table[DETECT_DATAREP].url = "/rules/dataset-keywords.html#datarep";
57  sigmatch_table[DETECT_DATAREP].Setup = DetectDatarepSetup;
59 
60  DetectSetupParseRegexes(PARSE_REGEX, &parse_regex);
61 }
62 
63 /*
64  1 match
65  0 no match
66  -1 can't match
67  */
69  const DetectDatarepData *sd,
70  const uint8_t *data, const uint32_t data_len)
71 {
72  if (data == NULL || data_len == 0)
73  return 0;
74 
75  DataRepResultType r = DatasetLookupwRep(sd->set, data, data_len, &sd->rep);
76  if (!r.found)
77  return 0;
78 
79  switch (sd->op) {
80  case DATAREP_OP_GT:
81  if (r.rep.value > sd->rep.value)
82  return 1;
83  break;
84  case DATAREP_OP_LT:
85  if (r.rep.value < sd->rep.value)
86  return 1;
87  break;
88  case DATAREP_OP_EQ:
89  if (r.rep.value == sd->rep.value)
90  return 1;
91  break;
92  }
93  return 0;
94 }
95 
96 static int DetectDatarepParse(const char *str, char *cmd, int cmd_len, char *name, int name_len,
97  enum DatasetTypes *type, char *load, size_t load_size, uint16_t *rep_value,
98  uint64_t *memcap, uint32_t *hashsize)
99 {
100  bool cmd_set = false;
101  bool name_set = false;
102  bool value_set = false;
103 
104  char copy[strlen(str)+1];
105  strlcpy(copy, str, sizeof(copy));
106  char *xsaveptr = NULL;
107  char *key = strtok_r(copy, ",", &xsaveptr);
108  while (key != NULL) {
109  while (*key != '\0' && isblank(*key)) {
110  key++;
111  }
112  char *val = strchr(key, ' ');
113  if (val != NULL) {
114  *val++ = '\0';
115  while (*val != '\0' && isblank(*val)) {
116  val++;
117  SCLogDebug("cmd %s val %s", key, val);
118  }
119  } else {
120  SCLogDebug("cmd %s", key);
121  }
122 
123  if (strlen(key) == 0) {
124  goto next;
125  }
126 
127  if (!name_set) {
128  if (val) {
129  return -1;
130  }
131  strlcpy(name, key, name_len);
132  name_set = true;
133  } else if (!cmd_set) {
134  if (val) {
135  return -1;
136  }
137  strlcpy(cmd, key, cmd_len);
138  cmd_set = true;
139  } else if (!value_set) {
140  if (val) {
141  return -1;
142  }
143 
144  if (StringParseUint16(rep_value, 10, 0, key) < 0)
145  return -1;
146 
147  value_set = true;
148  } else {
149  if (val == NULL) {
150  return -1;
151  }
152 
153  if (strcmp(key, "type") == 0) {
154  SCLogDebug("type %s", val);
155 
156  if (strcmp(val, "md5") == 0) {
158  } else if (strcmp(val, "sha256") == 0) {
160  } else if (strcmp(val, "string") == 0) {
162  } else if (strcmp(val, "ipv4") == 0) {
164  } else if (strcmp(val, "ip") == 0) {
166  } else if (strcmp(val, "ipv6") == 0) {
168  } else {
169  SCLogDebug("bad type %s", val);
170  return -1;
171  }
172 
173  } else if (strcmp(key, "load") == 0) {
174  SCLogDebug("load %s", val);
175  strlcpy(load, val, load_size);
176  }
177  if (strcmp(key, "memcap") == 0) {
178  if (ParseSizeStringU64(val, memcap) < 0) {
180  "invalid value for memcap: %s,"
181  " resetting to default",
182  val);
183  *memcap = 0;
184  }
185  }
186  if (strcmp(key, "hashsize") == 0) {
187  if (ParseSizeStringU32(val, hashsize) < 0) {
189  "invalid value for hashsize: %s,"
190  " resetting to default",
191  val);
192  *hashsize = 0;
193  }
194  }
195  }
196 
197  SCLogDebug("key: %s, value: %s", key, val);
198 
199  next:
200  key = strtok_r(NULL, ",", &xsaveptr);
201  }
202 
203  if (strlen(load) > 0 && *type == DATASET_TYPE_NOTSET) {
205  "if load is used type must be set as well");
206  return 0;
207  }
208 
209  if (!name_set || !cmd_set || !value_set) {
211  "missing values");
212  return 0;
213  }
214 
215  /* Trim trailing whitespace. */
216  while (strlen(name) > 0 && isblank(name[strlen(name) - 1])) {
217  name[strlen(name) - 1] = '\0';
218  }
219 
220  /* Validate name, spaces are not allowed. */
221  for (size_t i = 0; i < strlen(name); i++) {
222  if (isblank(name[i])) {
224  "spaces not allowed in dataset names");
225  return 0;
226  }
227  }
228 
229  return 1;
230 }
231 
232 /** \brief wrapper around dirname that does leave input untouched */
233 static void GetDirName(const char *in, char *out, size_t outs)
234 {
235  if (strlen(in) == 0) {
236  return;
237  }
238 
239  size_t size = strlen(in) + 1;
240  char tmp[size];
241  strlcpy(tmp, in, size);
242 
243  char *dir = dirname(tmp);
244  BUG_ON(dir == NULL);
245  strlcpy(out, dir, outs);
246  return;
247 }
248 
249 static int SetupLoadPath(const DetectEngineCtx *de_ctx,
250  char *load, size_t load_size)
251 {
252  SCLogDebug("load %s", load);
253 
254  if (PathIsAbsolute(load)) {
255  return 0;
256  }
257 
258  bool done = false;
259 #ifdef HAVE_LIBGEN_H
260  BUG_ON(de_ctx->rule_file == NULL);
261 
262  char dir[PATH_MAX] = "";
263  GetDirName(de_ctx->rule_file, dir, sizeof(dir));
264 
265  SCLogDebug("rule_file %s dir %s", de_ctx->rule_file, dir);
266  char path[PATH_MAX];
267  if (snprintf(path, sizeof(path), "%s/%s", dir, load) >= (int)sizeof(path)) // TODO windows path
268  return -1;
269 
270  if (SCPathExists(path)) {
271  done = true;
272  strlcpy(load, path, load_size);
273  SCLogDebug("using path '%s' (HAVE_LIBGEN_H)", load);
274  } else {
275  SCLogDebug("path '%s' does not exist (HAVE_LIBGEN_H)", path);
276  }
277 #endif
278  if (!done) {
279  char *loadp = DetectLoadCompleteSigPath(de_ctx, load);
280  if (loadp == NULL) {
281  return -1;
282  }
283  SCLogDebug("loadp %s", loadp);
284 
285  if (SCPathExists(loadp)) {
286  strlcpy(load, loadp, load_size);
287  SCLogDebug("using path '%s' (non-HAVE_LIBGEN_H)", load);
288  } else {
289  SCLogDebug("path '%s' does not exist (non-HAVE_LIBGEN_H)", loadp);
290  }
291  SCFree(loadp);
292 
293  // TODO try data-dir as well?
294  }
295  return 0;
296 }
297 
298 static int DetectDatarepSetup (DetectEngineCtx *de_ctx, Signature *s, const char *rawstr)
299 {
300  SigMatch *sm = NULL;
301  char cmd_str[16] = "", name[64] = "";
303  char load[PATH_MAX] = "";
304  uint16_t value = 0;
305  uint64_t memcap = 0;
306  uint32_t hashsize = 0;
307 
308  if (DetectBufferGetActiveList(de_ctx, s) == -1) {
310  "datarep is only supported for sticky buffers");
311  SCReturnInt(-1);
312  }
313 
314  int list = s->init_data->list;
315  if (list == DETECT_SM_LIST_NOTSET) {
317  "datarep is only supported for sticky buffers");
318  SCReturnInt(-1);
319  }
320 
321  if (!DetectDatarepParse(rawstr, cmd_str, sizeof(cmd_str), name, sizeof(name), &type, load,
322  sizeof(load), &value, &memcap, &hashsize)) {
323  return -1;
324  }
325 
326  if (strlen(load) != 0) {
327  if (SetupLoadPath(de_ctx, load, sizeof(load)) != 0)
328  return -1;
329  }
330 
331  enum DetectDatarepOp op;
332  if (strcmp(cmd_str,">") == 0) {
333  op = DATAREP_OP_GT;
334  } else if (strcmp(cmd_str,"<") == 0) {
335  op = DATAREP_OP_LT;
336  } else if (strcmp(cmd_str,"==") == 0) {
337  op = DATAREP_OP_EQ;
338  } else {
340  "datarep operation \"%s\" is not supported.", cmd_str);
341  return -1;
342  }
343 
344  Dataset *set = DatasetGet(name, type, /* no save */ NULL, load, memcap, hashsize);
345  if (set == NULL) {
347  "failed to set up datarep set '%s'.", name);
348  return -1;
349  }
350 
351  DetectDatarepData *cd = SCCalloc(1, sizeof(DetectDatarepData));
352  if (unlikely(cd == NULL))
353  goto error;
354 
355  cd->set = set;
356  cd->op = op;
357  cd->rep.value = value;
358 
359  SCLogDebug("cmd %s, name %s",
360  cmd_str, strlen(name) ? name : "(none)");
361 
362  /* Okay so far so good, lets get this into a SigMatch
363  * and put it in the Signature. */
364  sm = SigMatchAlloc();
365  if (sm == NULL)
366  goto error;
367 
368  sm->type = DETECT_DATAREP;
369  sm->ctx = (SigMatchCtx *)cd;
370  SigMatchAppendSMToList(s, sm, list);
371  return 0;
372 
373 error:
374  if (cd != NULL)
375  SCFree(cd);
376  if (sm != NULL)
377  SCFree(sm);
378  return -1;
379 }
380 
382 {
384 
385  if (fd == NULL)
386  return;
387 
388  SCFree(fd);
389 }
util-byte.h
SigTableElmt_::url
const char * url
Definition: detect.h:1238
detect-engine.h
DataRepResultType::rep
DataRepType rep
Definition: datasets-reputation.h:33
SigTableElmt_::desc
const char * desc
Definition: detect.h:1237
SC_ERR_INVALID_VALUE
@ SC_ERR_INVALID_VALUE
Definition: util-error.h:160
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
DetectEngineCtx_::rule_file
char * rule_file
Definition: detect.h:889
unlikely
#define unlikely(expr)
Definition: util-optimize.h:35
SCLogDebug
#define SCLogDebug(...)
Definition: util-debug.h:296
ParseSizeStringU64
int ParseSizeStringU64(const char *size, uint64_t *res)
Definition: util-misc.c:200
next
struct HtpBodyChunk_ * next
Definition: app-layer-htp.h:0
DetectDatarepData_
Definition: detect-datarep.h:36
threads.h
DetectDatarepMatch
int DetectDatarepMatch(ThreadVars *, DetectEngineThreadCtx *, Packet *, const Signature *, const SigMatchCtx *)
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:784
StringParseUint16
int StringParseUint16(uint16_t *res, int base, size_t len, const char *str)
Definition: util-byte.c:336
DETECT_DATAREP
@ DETECT_DATAREP
Definition: detect-engine-register.h:102
DataRepResultType::found
bool found
Definition: datasets-reputation.h:32
SC_ERR_INVALID_SIGNATURE
@ SC_ERR_INVALID_SIGNATURE
Definition: util-error.h:69
DATASET_TYPE_SHA256
@ DATASET_TYPE_SHA256
Definition: datasets.h:34
DetectDatarepRegister
void DetectDatarepRegister(void)
Definition: detect-datarep.c:52
DATAREP_OP_EQ
@ DATAREP_OP_EQ
Definition: detect-datarep.h:33
DetectBufferGetActiveList
int DetectBufferGetActiveList(DetectEngineCtx *de_ctx, Signature *s)
Definition: detect-engine.c:1312
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1220
DATASET_TYPE_IPV6
@ DATASET_TYPE_IPV6
Definition: datasets.h:36
hashsize
#define hashsize(n)
Definition: util-hash-lookup3.c:67
strlcpy
size_t strlcpy(char *dst, const char *src, size_t siz)
Definition: util-strlcpyu.c:43
DataRepResultType
Definition: datasets-reputation.h:31
DatasetGet
Dataset * DatasetGet(const char *name, enum DatasetTypes type, const char *save, const char *load, uint64_t memcap, uint32_t hashsize)
Definition: datasets.c:655
datasets.h
decode.h
util-debug.h
type
uint8_t type
Definition: decode-icmpv4.h:0
de_ctx
DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:17
DetectEngineThreadCtx_
Definition: detect.h:1024
SC_ERR_UNKNOWN_VALUE
@ SC_ERR_UNKNOWN_VALUE
Definition: util-error.h:159
DetectDatarepData_::rep
DataRepType rep
Definition: detect-datarep.h:40
DATASET_TYPE_NOTSET
#define DATASET_TYPE_NOTSET
Definition: datasets.h:31
DetectSetupParseRegexes
void DetectSetupParseRegexes(const char *parse_str, DetectParseRegex *detect_parse)
Definition: detect-parse.c:2611
SignatureInitData_::list
int list
Definition: detect.h:516
util-print.h
detect-engine-mpm.h
DetectDatarepOp
DetectDatarepOp
Definition: detect-datarep.h:30
detect.h
ThreadVars_
Per thread variable structure.
Definition: threadvars.h:57
SigMatch_::ctx
SigMatchCtx * ctx
Definition: detect.h:316
BUG_ON
#define BUG_ON(x)
Definition: suricata-common.h:289
Packet_
Definition: decode.h:428
DATAREP_OP_LT
@ DATAREP_OP_LT
Definition: detect-datarep.h:32
Signature_::init_data
SignatureInitData * init_data
Definition: detect.h:610
DATASET_TYPE_IPV4
@ DATASET_TYPE_IPV4
Definition: datasets.h:35
detect-engine-state.h
Data structures and function prototypes for keeping state for the detection engine.
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
DETECT_SM_LIST_NOTSET
#define DETECT_SM_LIST_NOTSET
Definition: detect.h:104
SCPathExists
bool SCPathExists(const char *path)
Check if a path exists.
Definition: util-path.c:169
DatasetTypes
DatasetTypes
Definition: datasets.h:30
DetectDatarepBufferMatch
int DetectDatarepBufferMatch(DetectEngineThreadCtx *det_ctx, const DetectDatarepData *sd, const uint8_t *data, const uint32_t data_len)
Definition: detect-datarep.c:68
suricata-common.h
DATAREP_OP_GT
@ DATAREP_OP_GT
Definition: detect-datarep.h:31
SigMatch_::type
uint16_t type
Definition: detect.h:314
util-path.h
sigmatch_table
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect-parse.c:76
PathIsAbsolute
int PathIsAbsolute(const char *path)
Check if a path is absolute.
Definition: util-path.c:44
SCLogError
#define SCLogError(err_code,...)
Macro used to log ERROR messages.
Definition: util-debug.h:255
DetectDatarepData_::set
Dataset * set
Definition: detect-datarep.h:37
DataRepType::value
uint16_t value
Definition: datasets-reputation.h:28
ParseSizeStringU32
int ParseSizeStringU32(const char *size, uint32_t *res)
Definition: util-misc.c:183
str
#define str(s)
Definition: suricata-common.h:280
SCLogWarning
#define SCLogWarning(err_code,...)
Macro used to log WARNING messages.
Definition: util-debug.h:242
detect-datarep.h
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
DATASET_TYPE_MD5
@ DATASET_TYPE_MD5
Definition: datasets.h:33
DATASET_TYPE_STRING
@ DATASET_TYPE_STRING
Definition: datasets.h:32
DetectDatarepFree
void DetectDatarepFree(DetectEngineCtx *, void *)
Definition: detect-datarep.c:381
DetectLoadCompleteSigPath
char * DetectLoadCompleteSigPath(const DetectEngineCtx *de_ctx, const char *sig_file)
Create the path if default-rule-path was specified.
Definition: detect-engine-loader.c:61
Dataset
Definition: datasets.h:40
DetectDatarepData_::op
enum DetectDatarepOp op
Definition: detect-datarep.h:39
util-misc.h
PARSE_REGEX
#define PARSE_REGEX
Definition: detect-datarep.c:44
SCCalloc
#define SCCalloc(nm, sz)
Definition: util-mem.h:53
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
DatasetLookupwRep
DataRepResultType DatasetLookupwRep(Dataset *set, const uint8_t *data, const uint32_t data_len, const DataRepType *rep)
Definition: datasets.c:1344