suricata
detect-stream_size.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 Gurvinder Singh <gurvindersinghdahiya@gmail.com>
22  *
23  * Stream size for the engine.
24  */
25 
26 #include "suricata-common.h"
27 #include "stream-tcp.h"
28 #include "util-unittest.h"
29 
30 #include "detect.h"
31 #include "detect-parse.h"
32 
33 #include "flow.h"
34 #include "detect-stream_size.h"
35 #include "stream-tcp-private.h"
37 #include "detect-engine-uint.h"
38 #include "util-debug.h"
39 #include "util-byte.h"
40 
41 
42 /*prototypes*/
43 static int DetectStreamSizeMatch (DetectEngineThreadCtx *, Packet *,
44  const Signature *, const SigMatchCtx *);
45 static int DetectStreamSizeSetup (DetectEngineCtx *, Signature *, const char *);
47 #ifdef UNITTESTS
48 static void DetectStreamSizeRegisterTests(void);
49 #endif
50 static int PrefilterSetupStreamSize(DetectEngineCtx *de_ctx, SigGroupHead *sgh);
51 static bool PrefilterStreamSizeIsPrefilterable(const Signature *s);
52 
53 /**
54  * \brief Registration function for stream_size: keyword
55  */
56 
58 {
59  sigmatch_table[DETECT_STREAM_SIZE].name = "stream_size";
60  sigmatch_table[DETECT_STREAM_SIZE].desc = "match on amount of bytes of a stream";
61  sigmatch_table[DETECT_STREAM_SIZE].url = "/rules/flow-keywords.html#stream-size";
62  sigmatch_table[DETECT_STREAM_SIZE].Match = DetectStreamSizeMatch;
63  sigmatch_table[DETECT_STREAM_SIZE].Setup = DetectStreamSizeSetup;
65 #ifdef UNITTESTS
66  sigmatch_table[DETECT_STREAM_SIZE].RegisterTests = DetectStreamSizeRegisterTests;
67 #endif
68  sigmatch_table[DETECT_STREAM_SIZE].SupportsPrefilter = PrefilterStreamSizeIsPrefilterable;
69  sigmatch_table[DETECT_STREAM_SIZE].SetupPrefilter = PrefilterSetupStreamSize;
70 }
71 
72 static int DetectStreamSizeMatchAux(const DetectStreamSizeData *sd, const TcpSession *ssn)
73 {
74  int ret = 0;
75  uint32_t csdiff = 0;
76  uint32_t ssdiff = 0;
77 
78  if (sd->flags == StreamSizeServer) {
79  /* get the server stream size */
80  ssdiff = ssn->server.next_seq - ssn->server.isn;
81  ret = DetectU32Match(ssdiff, &sd->du32);
82 
83  } else if (sd->flags == StreamSizeClient) {
84  /* get the client stream size */
85  csdiff = ssn->client.next_seq - ssn->client.isn;
86  ret = DetectU32Match(csdiff, &sd->du32);
87 
88  } else if (sd->flags == StreamSizeBoth) {
89  ssdiff = ssn->server.next_seq - ssn->server.isn;
90  csdiff = ssn->client.next_seq - ssn->client.isn;
91 
92  if (DetectU32Match(ssdiff, &sd->du32) && DetectU32Match(csdiff, &sd->du32))
93  ret = 1;
94 
95  } else if (sd->flags == StreamSizeEither) {
96  ssdiff = ssn->server.next_seq - ssn->server.isn;
97  csdiff = ssn->client.next_seq - ssn->client.isn;
98 
99  if (DetectU32Match(ssdiff, &sd->du32) || DetectU32Match(csdiff, &sd->du32))
100  ret = 1;
101  }
102  return ret;
103 }
104 
105 /**
106  * \brief This function is used to match Stream size rule option on a packet with those passed via
107  * stream_size:
108  *
109  * \param t pointer to thread vars
110  * \param det_ctx pointer to the pattern matcher thread
111  * \param p pointer to the current packet
112  * \param m pointer to the sigmatch that we will cast into DetectStreamSizeData
113  *
114  * \retval 0 no match
115  * \retval 1 match
116  */
117 static int DetectStreamSizeMatch(
118  DetectEngineThreadCtx *det_ctx, Packet *p, const Signature *s, const SigMatchCtx *ctx)
119 {
120 
121  const DetectStreamSizeData *sd = (const DetectStreamSizeData *)ctx;
122 
123  if (!(PKT_IS_TCP(p)))
124  return 0;
125  if (p->flow == NULL || p->flow->protoctx == NULL)
126  return 0;
127 
128  const TcpSession *ssn = (TcpSession *)p->flow->protoctx;
129 
130  SCReturnInt(DetectStreamSizeMatchAux(sd, ssn));
131 }
132 
133 /**
134  * \brief this function is used to add the parsed stream size data into the current signature
135  *
136  * \param de_ctx pointer to the Detection Engine Context
137  * \param s pointer to the Current Signature
138  * \param streamstr pointer to the user provided stream size options
139  *
140  * \retval 0 on Success
141  * \retval -1 on Failure
142  */
143 static int DetectStreamSizeSetup (DetectEngineCtx *de_ctx, Signature *s, const char *streamstr)
144 {
145  DetectStreamSizeData *sd = rs_detect_stream_size_parse(streamstr);
146  if (sd == NULL)
147  return -1;
148 
149  SigMatch *sm = SigMatchAlloc();
150  if (sm == NULL) {
152  return -1;
153  }
154 
155  sm->type = DETECT_STREAM_SIZE;
156  sm->ctx = (SigMatchCtx *)sd;
157 
159  return 0;
160 }
161 
162 /**
163  * \brief this function will free memory associated with DetectStreamSizeData
164  *
165  * \param ptr pointer to DetectStreamSizeData
166  */
168 {
169  rs_detect_stream_size_free(ptr);
170 }
171 
172 /* prefilter code */
173 
174 static void PrefilterPacketStreamsizeMatch(
175  DetectEngineThreadCtx *det_ctx, Packet *p, const void *pectx)
176 {
177  if (!(PKT_IS_TCP(p)) || PKT_IS_PSEUDOPKT(p))
178  return;
179 
180  if (p->flow == NULL || p->flow->protoctx == NULL)
181  return;
182 
183  /* during setup Suricata will automatically see if there is another
184  * check that can be added: alproto, sport or dport */
185  const PrefilterPacketHeaderCtx *ctx = pectx;
186  if (!PrefilterPacketHeaderExtraMatch(ctx, p))
187  return;
188 
189  DetectStreamSizeData dsd;
190  dsd.du32.mode = ctx->v1.u8[0];
191  dsd.flags = ctx->v1.u8[1];
192  dsd.du32.arg1 = ctx->v1.u32[2];
193  const TcpSession *ssn = (TcpSession *)p->flow->protoctx;
194  /* if we match, add all the sigs that use this prefilter. This means
195  * that these will be inspected further */
196  if (DetectStreamSizeMatchAux(&dsd, ssn)) {
197  PrefilterAddSids(&det_ctx->pmq, ctx->sigs_array, ctx->sigs_cnt);
198  }
199 }
200 
201 static void PrefilterPacketStreamSizeSet(PrefilterPacketHeaderValue *v, void *smctx)
202 {
203  const DetectStreamSizeData *a = smctx;
204  v->u8[0] = a->du32.mode;
205  v->u8[1] = a->flags;
206  v->u32[2] = a->du32.arg1;
207 }
208 
209 static bool PrefilterPacketStreamSizeCompare(PrefilterPacketHeaderValue v, void *smctx)
210 {
211  const DetectStreamSizeData *a = smctx;
212  if (v.u8[0] == a->du32.mode && v.u8[1] == a->flags && v.u32[2] == a->du32.arg1)
213  return true;
214  return false;
215 }
216 
217 static int PrefilterSetupStreamSize(DetectEngineCtx *de_ctx, SigGroupHead *sgh)
218 {
219  return PrefilterSetupPacketHeader(de_ctx, sgh, DETECT_TCPMSS, PrefilterPacketStreamSizeSet,
220  PrefilterPacketStreamSizeCompare, PrefilterPacketStreamsizeMatch);
221 }
222 
223 static bool PrefilterStreamSizeIsPrefilterable(const Signature *s)
224 {
225  const SigMatch *sm;
226  for (sm = s->init_data->smlists[DETECT_SM_LIST_MATCH]; sm != NULL; sm = sm->next) {
227  switch (sm->type) {
228  case DETECT_STREAM_SIZE:
229  return true;
230  }
231  }
232  return false;
233 }
234 
235 #ifdef UNITTESTS
236 /**
237  * \test DetectStreamSizeParseTest01 is a test to make sure that we parse the
238  * user options correctly, when given valid stream_size options.
239  */
240 
241 static int DetectStreamSizeParseTest01 (void)
242 {
243  int result = 0;
244  DetectStreamSizeData *sd = NULL;
245  sd = rs_detect_stream_size_parse("server,<,6");
246  if (sd != NULL) {
247  if (sd->flags & StreamSizeServer && sd->du32.mode == DETECT_UINT_LT && sd->du32.arg1 == 6)
248  result = 1;
249  DetectStreamSizeFree(NULL, sd);
250  }
251 
252  return result;
253 }
254 
255 /**
256  * \test DetectStreamSizeParseTest02 is a test to make sure that we detect the
257  * invalid stream_size options.
258  */
259 
260 static int DetectStreamSizeParseTest02 (void)
261 {
262  int result = 1;
263  DetectStreamSizeData *sd = NULL;
264  sd = rs_detect_stream_size_parse("invalidoption,<,6");
265  if (sd != NULL) {
266  printf("expected: NULL got 0x%02X %" PRIu32 ": ", sd->flags, sd->du32.arg1);
267  result = 0;
268  DetectStreamSizeFree(NULL, sd);
269  }
270 
271  return result;
272 }
273 
274 /**
275  * \test DetectStreamSizeParseTest03 is a test to make sure that we match the
276  * packet correctly provided valid stream size.
277  */
278 
279 static int DetectStreamSizeParseTest03 (void)
280 {
281 
282  int result = 0;
283  DetectStreamSizeData *sd = NULL;
284  TcpSession ssn;
285  ThreadVars tv;
287  Packet *p = PacketGetFromAlloc();
288  if (unlikely(p == NULL))
289  return 0;
290  Signature s;
291  SigMatch sm;
292  TcpStream client;
293  Flow f;
294  TCPHdr tcph;
295 
296  memset(&ssn, 0, sizeof(TcpSession));
297  memset(&tv, 0, sizeof(ThreadVars));
298  memset(&dtx, 0, sizeof(DetectEngineThreadCtx));
299  memset(&s, 0, sizeof(Signature));
300  memset(&sm, 0, sizeof(SigMatch));
301  memset(&client, 0, sizeof(TcpStream));
302  memset(&f, 0, sizeof(Flow));
303  memset(&tcph, 0, sizeof(TCPHdr));
304 
305  sd = rs_detect_stream_size_parse("client,>,8");
306  if (sd != NULL) {
307  if (!(sd->flags & StreamSizeClient)) {
308  printf("sd->flags not STREAM_SIZE_CLIENT: ");
309  DetectStreamSizeFree(NULL, sd);
310  SCFree(p);
311  return 0;
312  }
313 
314  if (sd->du32.mode != DETECT_UINT_GT) {
315  printf("sd->mode not DETECTSSIZE_GT: ");
316  DetectStreamSizeFree(NULL, sd);
317  SCFree(p);
318  return 0;
319  }
320 
321  if (sd->du32.arg1 != 8) {
322  printf("sd->ssize is %" PRIu32 ", not 8: ", sd->du32.arg1);
323  DetectStreamSizeFree(NULL, sd);
324  SCFree(p);
325  return 0;
326  }
327  } else {
328  printf("sd == NULL: ");
329  SCFree(p);
330  return 0;
331  }
332 
333  client.next_seq = 20;
334  client.isn = 10;
335  ssn.client = client;
336  f.protoctx = &ssn;
337  p->flow = &f;
338  p->tcph = &tcph;
339  sm.ctx = (SigMatchCtx*)sd;
340 
341  result = DetectStreamSizeMatch(&dtx, p, &s, sm.ctx);
342  if (result == 0) {
343  printf("result 0 != 1: ");
344  }
345  DetectStreamSizeFree(NULL, sd);
346  SCFree(p);
347  return result;
348 }
349 
350 /**
351  * \test DetectStreamSizeParseTest04 is a test to make sure that we match the
352  * stream_size against invalid packet parameters.
353  */
354 
355 static int DetectStreamSizeParseTest04 (void)
356 {
357 
358  int result = 0;
359  DetectStreamSizeData *sd = NULL;
360  TcpSession ssn;
361  ThreadVars tv;
363  Packet *p = PacketGetFromAlloc();
364  if (unlikely(p == NULL))
365  return 0;
366  Signature s;
367  SigMatch sm;
368  TcpStream client;
369  Flow f;
370  IPV4Hdr ip4h;
371 
372  memset(&ssn, 0, sizeof(TcpSession));
373  memset(&tv, 0, sizeof(ThreadVars));
374  memset(&dtx, 0, sizeof(DetectEngineThreadCtx));
375  memset(&s, 0, sizeof(Signature));
376  memset(&sm, 0, sizeof(SigMatch));
377  memset(&client, 0, sizeof(TcpStream));
378  memset(&f, 0, sizeof(Flow));
379  memset(&ip4h, 0, sizeof(IPV4Hdr));
380 
381  sd = rs_detect_stream_size_parse(" client , > , 8 ");
382  if (sd != NULL) {
383  if (!(sd->flags & StreamSizeClient) && sd->du32.mode != DETECT_UINT_GT &&
384  sd->du32.arg1 != 8) {
385  SCFree(p);
386  return 0;
387  }
388  } else
389  {
390  SCFree(p);
391  return 0;
392  }
393 
394  client.next_seq = 20;
395  client.isn = 12;
396  ssn.client = client;
397  f.protoctx = &ssn;
398  p->flow = &f;
399  p->ip4h = &ip4h;
400  sm.ctx = (SigMatchCtx*)sd;
401 
402  if (!DetectStreamSizeMatch(&dtx, p, &s, sm.ctx))
403  result = 1;
404 
405  SCFree(p);
406  return result;
407 }
408 
409 /**
410  * \brief this function registers unit tests for DetectStreamSize
411  */
412 void DetectStreamSizeRegisterTests(void)
413 {
414  UtRegisterTest("DetectStreamSizeParseTest01", DetectStreamSizeParseTest01);
415  UtRegisterTest("DetectStreamSizeParseTest02", DetectStreamSizeParseTest02);
416  UtRegisterTest("DetectStreamSizeParseTest03", DetectStreamSizeParseTest03);
417  UtRegisterTest("DetectStreamSizeParseTest04", DetectStreamSizeParseTest04);
418 }
419 #endif /* UNITTESTS */
util-byte.h
detect-engine-uint.h
SigTableElmt_::url
const char * url
Definition: detect.h:1238
TcpStream_
Definition: stream-tcp-private.h:106
TcpStream_::isn
uint32_t isn
Definition: stream-tcp-private.h:113
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int DetectU32Match(const uint32_t parg, const DetectUintData_u32 *du32)
Definition: detect-engine-uint.c:31
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const char * desc
Definition: detect.h:1237
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void(* Free)(DetectEngineCtx *, void *)
Definition: detect.h:1225
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const char * name
Definition: detect.h:1235
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#define PKT_IS_PSEUDOPKT(p)
return 1 if the packet is a pseudo packet
Definition: decode.h:1052
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Container for matching data for a signature group.
Definition: detect.h:1393
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#define unlikely(expr)
Definition: util-optimize.h:35
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void UtRegisterTest(const char *name, int(*TestFn)(void))
Register unit test.
Definition: util-unittest.c:103
DETECT_UINT_LT
#define DETECT_UINT_LT
Definition: detect-engine-uint.h:37
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Flow data structure.
Definition: flow.h:356
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Definition: detect.h:1131
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Definition: detect.h:784
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@ DETECT_STREAM_SIZE
Definition: detect-engine-register.h:99
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Definition: detect-engine-prefilter-common.h:43
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uint8_t u8[16]
Definition: detect-engine-prefilter-common.h:24
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Definition: detect-engine-prefilter-common.h:42
DETECT_UINT_GT
#define DETECT_UINT_GT
Definition: detect-engine-uint.h:32
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void * protoctx
Definition: flow.h:454
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int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1220
util-unittest.h
detect-stream_size.h
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int(* SetupPrefilter)(DetectEngineCtx *de_ctx, struct SigGroupHead_ *sgh)
Definition: detect.h:1223
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#define PKT_IS_TCP(p)
Definition: decode.h:244
PrefilterPacketHeaderCtx_
Definition: detect-engine-prefilter-common.h:35
util-debug.h
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DetectEngineCtx * de_ctx
Definition: fuzz_siginit.c:17
DetectEngineThreadCtx_
Definition: detect.h:1024
PrefilterPacketHeaderValue::u32
uint32_t u32[4]
Definition: detect-engine-prefilter-common.h:26
detect.h
ThreadVars_
Per thread variable structure.
Definition: threadvars.h:57
SigMatch_::next
struct SigMatch_ * next
Definition: detect.h:317
DETECT_SM_LIST_MATCH
@ DETECT_SM_LIST_MATCH
Definition: detect.h:78
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Definition: detect.h:316
Packet_
Definition: decode.h:425
stream-tcp-private.h
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void DetectStreamSizeFree(DetectEngineCtx *de_ctx, void *)
this function will free memory associated with DetectStreamSizeData
Definition: detect-stream_size.c:167
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IPV4Hdr * ip4h
Definition: decode.h:525
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SignatureInitData * init_data
Definition: detect.h:610
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int(* Match)(DetectEngineThreadCtx *, Packet *, const Signature *, const SigMatchCtx *)
Definition: detect.h:1203
SignatureInitData_::smlists
struct SigMatch_ ** smlists
Definition: detect.h:533
SigMatchAlloc
SigMatch * SigMatchAlloc(void)
Definition: detect-parse.c:238
PrefilterPacketHeaderCtx_::v1
PrefilterPacketHeaderValue v1
Definition: detect-engine-prefilter-common.h:36
SigMatchCtx_
Used to start a pointer to SigMatch context Should never be dereferenced without casting to something...
Definition: detect.h:308
IPV4Hdr_
Definition: decode-ipv4.h:72
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struct Flow_ * flow
Definition: decode.h:462
suricata-common.h
SigMatch_::type
uint16_t type
Definition: detect.h:314
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Definition: decode.h:547
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Definition: detect-parse.c:76
TcpSession_::client
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Definition: stream-tcp-private.h:285
tv
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Definition: fuzz_decodepcapfile.c:32
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:417
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uint32_t next_seq
Definition: stream-tcp-private.h:114
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Packet * PacketGetFromAlloc(void)
Get a malloced packet.
Definition: decode.c:173
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Definition: stream-tcp-private.h:284
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#define SCFree(p)
Definition: util-mem.h:61
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bool(* SupportsPrefilter)(const Signature *s)
Definition: detect.h:1222
DetectStreamSizeRegister
void DetectStreamSizeRegister(void)
Registration function for stream_size: keyword.
Definition: detect-stream_size.c:57
detect-parse.h
Signature_
Signature container.
Definition: detect.h:539
SigMatch_
a single match condition for a signature
Definition: detect.h:313
PrefilterPacketHeaderValue
Definition: detect-engine-prefilter-common.h:23
detect-engine-prefilter-common.h
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Definition: stream-tcp-private.h:272
flow.h
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
DETECT_TCPMSS
@ DETECT_TCPMSS
Definition: detect-engine-register.h:277
SigTableElmt_::RegisterTests
void(* RegisterTests)(void)
Definition: detect.h:1227