suricata
detect-id.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
20  *
21  * \author Pablo Rincon Crespo <pablo.rincon.crespo@gmail.com>
22  *
23  * Implements the id keyword
24  */
25 
26 #include "suricata-common.h"
27 #include "debug.h"
28 #include "decode.h"
29 #include "detect.h"
30 
31 #include "detect-parse.h"
32 #include "detect-engine.h"
33 #include "detect-engine-mpm.h"
35 
36 #include "detect-id.h"
37 #include "flow.h"
38 #include "flow-var.h"
39 
40 #include "util-debug.h"
41 #include "util-byte.h"
42 #include "util-unittest.h"
43 #include "util-unittest-helper.h"
44 
45 /**
46  * \brief Regex for parsing "id" option, matching number or "number"
47  */
48 #define PARSE_REGEX "^\\s*([0-9]{1,5}|\"[0-9]{1,5}\")\\s*$"
49 
50 static DetectParseRegex parse_regex;
51 
52 static int DetectIdMatch (DetectEngineThreadCtx *, Packet *,
53  const Signature *, const SigMatchCtx *);
54 static int DetectIdSetup (DetectEngineCtx *, Signature *, const char *);
55 #ifdef UNITTESTS
56 static void DetectIdRegisterTests(void);
57 #endif
58 void DetectIdFree(DetectEngineCtx *, void *);
59 
60 static int PrefilterSetupId(DetectEngineCtx *de_ctx, SigGroupHead *sgh);
61 static bool PrefilterIdIsPrefilterable(const Signature *s);
62 
63 /**
64  * \brief Registration function for keyword: id
65  */
66 void DetectIdRegister (void)
67 {
69  sigmatch_table[DETECT_ID].desc = "match on a specific IP ID value";
70  sigmatch_table[DETECT_ID].url = "/rules/header-keywords.html#id";
71  sigmatch_table[DETECT_ID].Match = DetectIdMatch;
72  sigmatch_table[DETECT_ID].Setup = DetectIdSetup;
74 #ifdef UNITTESTS
75  sigmatch_table[DETECT_ID].RegisterTests = DetectIdRegisterTests;
76 #endif
77  sigmatch_table[DETECT_ID].SupportsPrefilter = PrefilterIdIsPrefilterable;
78  sigmatch_table[DETECT_ID].SetupPrefilter = PrefilterSetupId;
79 
80  DetectSetupParseRegexes(PARSE_REGEX, &parse_regex);
81 }
82 
83 /**
84  * \brief This function is used to match the specified id on a packet
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 DetectIdData
90  *
91  * \retval 0 no match
92  * \retval 1 match
93  */
94 static int DetectIdMatch (DetectEngineThreadCtx *det_ctx, Packet *p,
95  const Signature *s, const SigMatchCtx *ctx)
96 {
97  const DetectIdData *id_d = (const DetectIdData *)ctx;
98 
99  /**
100  * To match a ipv4 packet with a "id" rule
101  */
102  if (!PKT_IS_IPV4(p) || PKT_IS_PSEUDOPKT(p)) {
103  return 0;
104  }
105 
106  if (id_d->id == IPV4_GET_IPID(p)) {
107  SCLogDebug("IPV4 Proto and matched with ip_id: %u.\n",
108  id_d->id);
109  return 1;
110  }
111 
112  return 0;
113 }
114 
115 /**
116  * \brief This function is used to parse IPV4 ip_id passed via keyword: "id"
117  *
118  * \param idstr Pointer to the user provided id option
119  *
120  * \retval id_d pointer to DetectIdData on success
121  * \retval NULL on failure
122  */
123 static DetectIdData *DetectIdParse (const char *idstr)
124 {
125  uint32_t temp;
126  DetectIdData *id_d = NULL;
127  int ret = 0, res = 0;
128  int ov[MAX_SUBSTRINGS];
129 
130  ret = DetectParsePcreExec(&parse_regex, idstr, 0, 0, ov, MAX_SUBSTRINGS);
131 
132  if (ret < 1 || ret > 3) {
133  SCLogError(SC_ERR_INVALID_VALUE, "invalid id option '%s'. The id option "
134  "value must be in the range %u - %u",
136  return NULL;
137  }
138 
139  char copy_str[128] = "";
140  char *tmp_str;
141  res = pcre_copy_substring((char *)idstr, ov, MAX_SUBSTRINGS, 1,
142  copy_str, sizeof(copy_str));
143  if (res < 0) {
144  SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_copy_substring failed");
145  return NULL;
146  }
147  tmp_str = copy_str;
148 
149  /* Let's see if we need to scape "'s */
150  if (tmp_str[0] == '"')
151  {
152  tmp_str[strlen(tmp_str) - 1] = '\0';
153  tmp_str += 1;
154  }
155 
156  /* ok, fill the id data */
157  if (StringParseU32RangeCheck(&temp, 10, 0, (const char *)tmp_str,
159  SCLogError(SC_ERR_INVALID_VALUE, "invalid id option '%s'", tmp_str);
160  return NULL;
161  }
162 
163  /* We have a correct id option */
164  id_d = SCMalloc(sizeof(DetectIdData));
165  if (unlikely(id_d == NULL))
166  return NULL;
167 
168  id_d->id = temp;
169 
170  SCLogDebug("detect-id: will look for ip_id: %u\n", id_d->id);
171  return id_d;
172 }
173 
174 /**
175  * \brief this function is used to add the parsed "id" option
176  * \brief into the current signature
177  *
178  * \param de_ctx pointer to the Detection Engine Context
179  * \param s pointer to the Current Signature
180  * \param idstr pointer to the user provided "id" option
181  *
182  * \retval 0 on Success
183  * \retval -1 on Failure
184  */
185 int DetectIdSetup (DetectEngineCtx *de_ctx, Signature *s, const char *idstr)
186 {
187  DetectIdData *id_d = NULL;
188  SigMatch *sm = NULL;
189 
190  id_d = DetectIdParse(idstr);
191  if (id_d == NULL)
192  return -1;
193 
194  /* Okay so far so good, lets get this into a SigMatch
195  * and put it in the Signature. */
196  sm = SigMatchAlloc();
197  if (sm == NULL) {
198  DetectIdFree(de_ctx, id_d);
199  return -1;
200  }
201 
202  sm->type = DETECT_ID;
203  sm->ctx = (SigMatchCtx *)id_d;
204 
207  return 0;
208 }
209 
210 /**
211  * \brief this function will free memory associated with DetectIdData
212  *
213  * \param id_d pointer to DetectIdData
214  */
216 {
217  DetectIdData *id_d = (DetectIdData *)ptr;
218  SCFree(id_d);
219 }
220 
221 /* prefilter code */
222 
223 static void
224 PrefilterPacketIdMatch(DetectEngineThreadCtx *det_ctx, Packet *p, const void *pectx)
225 {
226  const PrefilterPacketHeaderCtx *ctx = pectx;
227 
228  if (!PKT_IS_IPV4(p) || PKT_IS_PSEUDOPKT(p)) {
229  return;
230  }
231 
232  if (PrefilterPacketHeaderExtraMatch(ctx, p) == FALSE)
233  return;
234 
235  if (IPV4_GET_IPID(p) == ctx->v1.u16[0])
236  {
237  SCLogDebug("packet matches IP id %u", ctx->v1.u16[0]);
238  PrefilterAddSids(&det_ctx->pmq, ctx->sigs_array, ctx->sigs_cnt);
239  }
240 }
241 
242 static void
243 PrefilterPacketIdSet(PrefilterPacketHeaderValue *v, void *smctx)
244 {
245  const DetectIdData *a = smctx;
246  v->u16[0] = a->id;
247 }
248 
249 static bool
250 PrefilterPacketIdCompare(PrefilterPacketHeaderValue v, void *smctx)
251 {
252  const DetectIdData *a = smctx;
253  if (v.u16[0] == a->id)
254  return TRUE;
255  return FALSE;
256 }
257 
258 static int PrefilterSetupId(DetectEngineCtx *de_ctx, SigGroupHead *sgh)
259 {
261  PrefilterPacketIdSet,
262  PrefilterPacketIdCompare,
263  PrefilterPacketIdMatch);
264 }
265 
266 static bool PrefilterIdIsPrefilterable(const Signature *s)
267 {
268  const SigMatch *sm;
269  for (sm = s->init_data->smlists[DETECT_SM_LIST_MATCH] ; sm != NULL; sm = sm->next) {
270  switch (sm->type) {
271  case DETECT_ID:
272  return TRUE;
273  }
274  }
275  return FALSE;
276 }
277 
278 #ifdef UNITTESTS /* UNITTESTS */
279 
280 /**
281  * \test DetectIdTestParse01 is a test to make sure that we parse the "id"
282  * option correctly when given valid id option
283  */
284 static int DetectIdTestParse01 (void)
285 {
286  DetectIdData *id_d = NULL;
287  id_d = DetectIdParse(" 35402 ");
288  if (id_d != NULL &&id_d->id==35402) {
289  DetectIdFree(NULL, id_d);
290  return 1;
291  }
292 
293  return 0;
294 }
295 
296 /**
297  * \test DetectIdTestParse02 is a test to make sure that we parse the "id"
298  * option correctly when given an invalid id option
299  * it should return id_d = NULL
300  */
301 static int DetectIdTestParse02 (void)
302 {
303  DetectIdData *id_d = NULL;
304  id_d = DetectIdParse("65537");
305  if (id_d == NULL) {
306  DetectIdFree(NULL, id_d);
307  return 1;
308  }
309 
310  return 0;
311 }
312 
313 /**
314  * \test DetectIdTestParse03 is a test to make sure that we parse the "id"
315  * option correctly when given an invalid id option
316  * it should return id_d = NULL
317  */
318 static int DetectIdTestParse03 (void)
319 {
320  DetectIdData *id_d = NULL;
321  id_d = DetectIdParse("12what?");
322  if (id_d == NULL) {
323  DetectIdFree(NULL, id_d);
324  return 1;
325  }
326 
327  return 0;
328 }
329 
330 /**
331  * \test DetectIdTestParse04 is a test to make sure that we parse the "id"
332  * option correctly when given valid id option but wrapped with "'s
333  */
334 static int DetectIdTestParse04 (void)
335 {
336  DetectIdData *id_d = NULL;
337  /* yep, look if we trim blank spaces correctly and ignore "'s */
338  id_d = DetectIdParse(" \"35402\" ");
339  if (id_d != NULL &&id_d->id==35402) {
340  DetectIdFree(NULL, id_d);
341  return 1;
342  }
343 
344  return 0;
345 }
346 
347 /**
348  * \test DetectIdTestSig01
349  * \brief Test to check "id" keyword with constructed packets
350  */
351 static int DetectIdTestMatch01(void)
352 {
353  int result = 0;
354  uint8_t *buf = (uint8_t *)"Hi all!";
355  uint16_t buflen = strlen((char *)buf);
356  Packet *p[3];
357  p[0] = UTHBuildPacket((uint8_t *)buf, buflen, IPPROTO_TCP);
358  p[1] = UTHBuildPacket((uint8_t *)buf, buflen, IPPROTO_UDP);
359  p[2] = UTHBuildPacket((uint8_t *)buf, buflen, IPPROTO_ICMP);
360 
361  if (p[0] == NULL || p[1] == NULL ||p[2] == NULL)
362  goto end;
363 
364  /* TCP IP id = 1234 */
365  p[0]->ip4h->ip_id = htons(1234);
366 
367  /* UDP IP id = 5678 */
368  p[1]->ip4h->ip_id = htons(5678);
369 
370  /* UDP IP id = 91011 */
371  p[2]->ip4h->ip_id = htons(5101);
372 
373  const char *sigs[3];
374  sigs[0]= "alert ip any any -> any any (msg:\"Testing id 1\"; id:1234; sid:1;)";
375  sigs[1]= "alert ip any any -> any any (msg:\"Testing id 2\"; id:5678; sid:2;)";
376  sigs[2]= "alert ip any any -> any any (msg:\"Testing id 3\"; id:5101; sid:3;)";
377 
378  uint32_t sid[3] = {1, 2, 3};
379 
380  uint32_t results[3][3] = {
381  /* packet 0 match sid 1 but should not match sid 2 */
382  {1, 0, 0},
383  /* packet 1 should not match */
384  {0, 1, 0},
385  /* packet 2 should not match */
386  {0, 0, 1} };
387 
388  result = UTHGenericTest(p, 3, sigs, sid, (uint32_t *) results, 3);
389 
390  UTHFreePackets(p, 3);
391 end:
392  return result;
393 }
394 
395 /**
396  * \brief this function registers unit tests for DetectId
397  */
398 void DetectIdRegisterTests(void)
399 {
400  UtRegisterTest("DetectIdTestParse01", DetectIdTestParse01);
401  UtRegisterTest("DetectIdTestParse02", DetectIdTestParse02);
402  UtRegisterTest("DetectIdTestParse03", DetectIdTestParse03);
403  UtRegisterTest("DetectIdTestParse04", DetectIdTestParse04);
404  UtRegisterTest("DetectIdTestMatch01", DetectIdTestMatch01);
405 
406 }
407 #endif /* UNITTESTS */
util-byte.h
SigTableElmt_::url
const char * url
Definition: detect.h:1214
detect-engine.h
SigTableElmt_::desc
const char * desc
Definition: detect.h:1213
SC_ERR_INVALID_VALUE
@ SC_ERR_INVALID_VALUE
Definition: util-error.h:160
SigTableElmt_::Free
void(* Free)(DetectEngineCtx *, void *)
Definition: detect.h:1201
SigTableElmt_::name
const char * name
Definition: detect.h:1211
PKT_IS_PSEUDOPKT
#define PKT_IS_PSEUDOPKT(p)
return 1 if the packet is a pseudo packet
Definition: decode.h:1147
SigGroupHead_
Container for matching data for a signature group.
Definition: detect.h:1347
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
SCLogDebug
#define SCLogDebug(...)
Definition: util-debug.h:298
DETECT_ID
@ DETECT_ID
Definition: detect-engine-register.h:80
results
struct DetectRfbSecresult_ results[]
DetectEngineThreadCtx_::pmq
PrefilterRuleStore pmq
Definition: detect.h:1111
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:767
DetectIdData_::id
uint16_t id
Definition: detect-id.h:32
PrefilterPacketHeaderCtx_::sigs_array
SigIntId * sigs_array
Definition: detect-engine-prefilter-common.h:41
PARSE_REGEX
#define PARSE_REGEX
Regex for parsing "id" option, matching number or "number".
Definition: detect-id.c:48
IPV4Hdr_::ip_id
uint16_t ip_id
Definition: decode-ipv4.h:75
UTHBuildPacket
Packet * UTHBuildPacket(uint8_t *payload, uint16_t payload_len, uint8_t ipproto)
UTHBuildPacket is a wrapper that build packets with default ip and port fields.
Definition: util-unittest-helper.c:337
PrefilterPacketHeaderCtx_::sigs_cnt
uint32_t sigs_cnt
Definition: detect-engine-prefilter-common.h:40
SC_ERR_PCRE_GET_SUBSTRING
@ SC_ERR_PCRE_GET_SUBSTRING
Definition: util-error.h:34
SigTableElmt_::Setup
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1196
PrefilterPacketHeaderValue::u16
uint16_t u16[8]
Definition: detect-engine-prefilter-common.h:23
util-unittest.h
util-unittest-helper.h
SigTableElmt_::SetupPrefilter
int(* SetupPrefilter)(DetectEngineCtx *de_ctx, struct SigGroupHead_ *sgh)
Definition: detect.h:1199
PrefilterPacketHeaderCtx_
Definition: detect-engine-prefilter-common.h:33
decode.h
util-debug.h
de_ctx
DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:17
DetectEngineThreadCtx_
Definition: detect.h:1010
res
PoolThreadReserved res
Definition: stream-tcp-private.h:0
DetectSetupParseRegexes
void DetectSetupParseRegexes(const char *parse_str, DetectParseRegex *detect_parse)
Definition: detect-parse.c:2493
StringParseU32RangeCheck
int StringParseU32RangeCheck(uint32_t *res, int base, uint16_t len, const char *str, uint32_t min, uint32_t max)
Definition: util-byte.c:401
detect-engine-mpm.h
detect.h
SigMatch_::next
struct SigMatch_ * next
Definition: detect.h:324
DetectIdRegister
void DetectIdRegister(void)
Registration function for keyword: id.
Definition: detect-id.c:66
DETECT_SM_LIST_MATCH
@ DETECT_SM_LIST_MATCH
Definition: detect.h:89
IPV4_GET_IPID
#define IPV4_GET_IPID(p)
Definition: decode-ipv4.h:129
TRUE
#define TRUE
Definition: suricata-common.h:33
SigMatch_::ctx
SigMatchCtx * ctx
Definition: detect.h:323
FALSE
#define FALSE
Definition: suricata-common.h:34
Signature_::flags
uint32_t flags
Definition: detect.h:529
DetectParsePcreExec
int DetectParsePcreExec(DetectParseRegex *parse_regex, const char *str, int start_offset, int options, int *ovector, int ovector_size)
Definition: detect-parse.c:2423
Packet_
Definition: decode.h:414
detect-id.h
Packet_::ip4h
IPV4Hdr * ip4h
Definition: decode.h:509
Signature_::init_data
SignatureInitData * init_data
Definition: detect.h:597
SigTableElmt_::Match
int(* Match)(DetectEngineThreadCtx *, Packet *, const Signature *, const SigMatchCtx *)
Definition: detect.h:1179
SignatureInitData_::smlists
struct SigMatch_ ** smlists
Definition: detect.h:522
SigMatchAlloc
SigMatch * SigMatchAlloc(void)
Definition: detect-parse.c:235
SigMatch_::type
uint8_t type
Definition: detect.h:321
PrefilterPacketHeaderCtx_::v1
PrefilterPacketHeaderValue v1
Definition: detect-engine-prefilter-common.h:34
SigMatchCtx_
Used to start a pointer to SigMatch context Should never be dereferenced without casting to something...
Definition: detect.h:315
DetectIdData_
Definition: detect-id.h:31
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
UTHGenericTest
int UTHGenericTest(Packet **pkt, int numpkts, const char *sigs[], uint32_t sids[], uint32_t *results, int numsigs)
UTHGenericTest: function that perfom a generic check taking care of as maximum common unittest elemen...
Definition: util-unittest-helper.c:604
PrefilterSetupPacketHeader
int PrefilterSetupPacketHeader(DetectEngineCtx *de_ctx, SigGroupHead *sgh, int sm_type, void(*Set)(PrefilterPacketHeaderValue *v, void *), bool(*Compare)(PrefilterPacketHeaderValue v, void *), void(*Match)(DetectEngineThreadCtx *det_ctx, Packet *p, const void *pectx))
Definition: detect-engine-prefilter-common.c:407
SCMalloc
#define SCMalloc(sz)
Definition: util-mem.h:47
DETECT_IPID_MAX
#define DETECT_IPID_MAX
Definition: detect-id.h:29
SCFree
#define SCFree(p)
Definition: util-mem.h:61
SigTableElmt_::SupportsPrefilter
bool(* SupportsPrefilter)(const Signature *s)
Definition: detect.h:1198
detect-parse.h
Signature_
Signature container.
Definition: detect.h:528
SigMatch_
a single match condition for a signature
Definition: detect.h:320
DETECT_IPID_MIN
#define DETECT_IPID_MIN
Definition: detect-id.h:28
DetectIdFree
void DetectIdFree(DetectEngineCtx *, void *)
this function will free memory associated with DetectIdData
Definition: detect-id.c:215
PrefilterPacketHeaderValue
Definition: detect-engine-prefilter-common.h:21
detect-engine-prefilter-common.h
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flow-var.h
PKT_IS_IPV4
#define PKT_IS_IPV4(p)
Definition: decode.h:257
SigMatchAppendSMToList
void SigMatchAppendSMToList(Signature *s, SigMatch *new, int list)
Append a SigMatch to the list type.
Definition: detect-parse.c:349
debug.h
SigTableElmt_::RegisterTests
void(* RegisterTests)(void)
Definition: detect.h:1203
SIG_FLAG_REQUIRE_PACKET
#define SIG_FLAG_REQUIRE_PACKET
Definition: detect.h:223
UTHFreePackets
void UTHFreePackets(Packet **p, int numpkts)
UTHFreePackets: function to release the allocated data from UTHBuildPacket and the packet itself.
Definition: util-unittest-helper.c:468