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 #include "util-unittest-helper.h"
30 
31 #include "detect.h"
32 #include "detect-parse.h"
33 
34 #include "flow.h"
35 #include "detect-stream_size.h"
36 #include "stream-tcp-private.h"
38 #include "detect-engine-uint.h"
39 #include "util-debug.h"
40 #include "util-byte.h"
41 
42 
43 /*prototypes*/
44 static int DetectStreamSizeMatch (DetectEngineThreadCtx *, Packet *,
45  const Signature *, const SigMatchCtx *);
46 static int DetectStreamSizeSetup (DetectEngineCtx *, Signature *, const char *);
48 #ifdef UNITTESTS
49 static void DetectStreamSizeRegisterTests(void);
50 #endif
51 static int PrefilterSetupStreamSize(DetectEngineCtx *de_ctx, SigGroupHead *sgh);
52 static bool PrefilterStreamSizeIsPrefilterable(const Signature *s);
53 
54 /**
55  * \brief Registration function for stream_size: keyword
56  */
57 
59 {
60  sigmatch_table[DETECT_STREAM_SIZE].name = "stream_size";
61  sigmatch_table[DETECT_STREAM_SIZE].desc = "match on amount of bytes of a stream";
62  sigmatch_table[DETECT_STREAM_SIZE].url = "/rules/flow-keywords.html#stream-size";
63  sigmatch_table[DETECT_STREAM_SIZE].Match = DetectStreamSizeMatch;
64  sigmatch_table[DETECT_STREAM_SIZE].Setup = DetectStreamSizeSetup;
66 #ifdef UNITTESTS
67  sigmatch_table[DETECT_STREAM_SIZE].RegisterTests = DetectStreamSizeRegisterTests;
68 #endif
69  sigmatch_table[DETECT_STREAM_SIZE].SupportsPrefilter = PrefilterStreamSizeIsPrefilterable;
70  sigmatch_table[DETECT_STREAM_SIZE].SetupPrefilter = PrefilterSetupStreamSize;
71 }
72 
73 static int DetectStreamSizeMatchAux(const DetectStreamSizeData *sd, const TcpSession *ssn)
74 {
75  int ret = 0;
76  uint32_t csdiff = 0;
77  uint32_t ssdiff = 0;
78 
79  if (sd->flags == StreamSizeServer) {
80  /* get the server stream size */
81  ssdiff = ssn->server.next_seq - ssn->server.isn;
82  ret = DetectU32Match(ssdiff, &sd->du32);
83 
84  } else if (sd->flags == StreamSizeClient) {
85  /* get the client stream size */
86  csdiff = ssn->client.next_seq - ssn->client.isn;
87  ret = DetectU32Match(csdiff, &sd->du32);
88 
89  } else if (sd->flags == StreamSizeBoth) {
90  ssdiff = ssn->server.next_seq - ssn->server.isn;
91  csdiff = ssn->client.next_seq - ssn->client.isn;
92 
93  if (DetectU32Match(ssdiff, &sd->du32) && DetectU32Match(csdiff, &sd->du32))
94  ret = 1;
95 
96  } else if (sd->flags == StreamSizeEither) {
97  ssdiff = ssn->server.next_seq - ssn->server.isn;
98  csdiff = ssn->client.next_seq - ssn->client.isn;
99 
100  if (DetectU32Match(ssdiff, &sd->du32) || DetectU32Match(csdiff, &sd->du32))
101  ret = 1;
102  }
103  return ret;
104 }
105 
106 /**
107  * \brief This function is used to match Stream size rule option on a packet with those passed via
108  * stream_size:
109  *
110  * \param t pointer to thread vars
111  * \param det_ctx pointer to the pattern matcher thread
112  * \param p pointer to the current packet
113  * \param m pointer to the sigmatch that we will cast into DetectStreamSizeData
114  *
115  * \retval 0 no match
116  * \retval 1 match
117  */
118 static int DetectStreamSizeMatch(
119  DetectEngineThreadCtx *det_ctx, Packet *p, const Signature *s, const SigMatchCtx *ctx)
120 {
121  const DetectStreamSizeData *sd = (const DetectStreamSizeData *)ctx;
122 
123  if (!(PacketIsTCP(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 
152  return -1;
153  }
154  return 0;
155 }
156 
157 /**
158  * \brief this function will free memory associated with DetectStreamSizeData
159  *
160  * \param ptr pointer to DetectStreamSizeData
161  */
163 {
164  rs_detect_stream_size_free(ptr);
165 }
166 
167 /* prefilter code */
168 
169 static void PrefilterPacketStreamsizeMatch(
170  DetectEngineThreadCtx *det_ctx, Packet *p, const void *pectx)
171 {
172  if (!(PacketIsTCP(p)))
173  return;
174 
175  if (p->flow == NULL || p->flow->protoctx == NULL)
176  return;
177 
178  /* during setup Suricata will automatically see if there is another
179  * check that can be added: alproto, sport or dport */
180  const PrefilterPacketHeaderCtx *ctx = pectx;
181  if (!PrefilterPacketHeaderExtraMatch(ctx, p))
182  return;
183 
184  DetectStreamSizeData dsd;
185  dsd.du32.mode = ctx->v1.u8[0];
186  dsd.flags = ctx->v1.u8[1];
187  dsd.du32.arg1 = ctx->v1.u32[2];
188  const TcpSession *ssn = (TcpSession *)p->flow->protoctx;
189  /* if we match, add all the sigs that use this prefilter. This means
190  * that these will be inspected further */
191  if (DetectStreamSizeMatchAux(&dsd, ssn)) {
192  PrefilterAddSids(&det_ctx->pmq, ctx->sigs_array, ctx->sigs_cnt);
193  }
194 }
195 
196 static void PrefilterPacketStreamSizeSet(PrefilterPacketHeaderValue *v, void *smctx)
197 {
198  const DetectStreamSizeData *a = smctx;
199  v->u8[0] = a->du32.mode;
200  v->u8[1] = a->flags;
201  v->u32[2] = a->du32.arg1;
202 }
203 
204 static bool PrefilterPacketStreamSizeCompare(PrefilterPacketHeaderValue v, void *smctx)
205 {
206  const DetectStreamSizeData *a = smctx;
207  if (v.u8[0] == a->du32.mode && v.u8[1] == a->flags && v.u32[2] == a->du32.arg1)
208  return true;
209  return false;
210 }
211 
212 static int PrefilterSetupStreamSize(DetectEngineCtx *de_ctx, SigGroupHead *sgh)
213 {
215  PrefilterPacketStreamSizeSet, PrefilterPacketStreamSizeCompare,
216  PrefilterPacketStreamsizeMatch);
217 }
218 
219 static bool PrefilterStreamSizeIsPrefilterable(const Signature *s)
220 {
221  const SigMatch *sm;
222  for (sm = s->init_data->smlists[DETECT_SM_LIST_MATCH]; sm != NULL; sm = sm->next) {
223  switch (sm->type) {
224  case DETECT_STREAM_SIZE:
225  return true;
226  }
227  }
228  return false;
229 }
230 
231 #ifdef UNITTESTS
232 /**
233  * \test DetectStreamSizeParseTest01 is a test to make sure that we parse the
234  * user options correctly, when given valid stream_size options.
235  */
236 
237 static int DetectStreamSizeParseTest01 (void)
238 {
239  int result = 0;
240  DetectStreamSizeData *sd = NULL;
241  sd = rs_detect_stream_size_parse("server,<,6");
242  if (sd != NULL) {
243  if (sd->flags & StreamSizeServer && sd->du32.mode == DETECT_UINT_LT && sd->du32.arg1 == 6)
244  result = 1;
245  DetectStreamSizeFree(NULL, sd);
246  }
247 
248  return result;
249 }
250 
251 /**
252  * \test DetectStreamSizeParseTest02 is a test to make sure that we detect the
253  * invalid stream_size options.
254  */
255 
256 static int DetectStreamSizeParseTest02 (void)
257 {
258  int result = 1;
259  DetectStreamSizeData *sd = NULL;
260  sd = rs_detect_stream_size_parse("invalidoption,<,6");
261  if (sd != NULL) {
262  printf("expected: NULL got 0x%02X %" PRIu32 ": ", sd->flags, sd->du32.arg1);
263  result = 0;
264  DetectStreamSizeFree(NULL, sd);
265  }
266 
267  return result;
268 }
269 
270 /**
271  * \test DetectStreamSizeParseTest03 is a test to make sure that we match the
272  * packet correctly provided valid stream size.
273  */
274 
275 static int DetectStreamSizeParseTest03 (void)
276 {
277 
278  int result = 0;
279  DetectStreamSizeData *sd = NULL;
280  TcpSession ssn;
281  ThreadVars tv;
283  Packet *p = PacketGetFromAlloc();
284  if (unlikely(p == NULL))
285  return 0;
286  Signature s;
287  SigMatch sm;
288  TcpStream client;
289  Flow f;
290  TCPHdr tcph;
291 
292  memset(&ssn, 0, sizeof(TcpSession));
293  memset(&tv, 0, sizeof(ThreadVars));
294  memset(&dtx, 0, sizeof(DetectEngineThreadCtx));
295  memset(&s, 0, sizeof(Signature));
296  memset(&sm, 0, sizeof(SigMatch));
297  memset(&client, 0, sizeof(TcpStream));
298  memset(&f, 0, sizeof(Flow));
299  memset(&tcph, 0, sizeof(TCPHdr));
300 
301  sd = rs_detect_stream_size_parse("client,>,8");
302  if (sd != NULL) {
303  if (!(sd->flags & StreamSizeClient)) {
304  printf("sd->flags not STREAM_SIZE_CLIENT: ");
305  DetectStreamSizeFree(NULL, sd);
306  SCFree(p);
307  return 0;
308  }
309 
310  if (sd->du32.mode != DETECT_UINT_GT) {
311  printf("sd->mode not DETECTSSIZE_GT: ");
312  DetectStreamSizeFree(NULL, sd);
313  SCFree(p);
314  return 0;
315  }
316 
317  if (sd->du32.arg1 != 8) {
318  printf("sd->ssize is %" PRIu32 ", not 8: ", sd->du32.arg1);
319  DetectStreamSizeFree(NULL, sd);
320  SCFree(p);
321  return 0;
322  }
323  } else {
324  printf("sd == NULL: ");
325  SCFree(p);
326  return 0;
327  }
328 
329  client.next_seq = 20;
330  client.isn = 10;
331  ssn.client = client;
332  f.protoctx = &ssn;
333  p->flow = &f;
334  PacketSetTCP(p, (uint8_t *)&tcph);
335  sm.ctx = (SigMatchCtx*)sd;
336 
337  result = DetectStreamSizeMatch(&dtx, p, &s, sm.ctx);
338  if (result == 0) {
339  printf("result 0 != 1: ");
340  }
341  DetectStreamSizeFree(NULL, sd);
342  SCFree(p);
343  return result;
344 }
345 
346 /**
347  * \test DetectStreamSizeParseTest04 is a test to make sure that we match the
348  * stream_size against invalid packet parameters.
349  */
350 
351 static int DetectStreamSizeParseTest04 (void)
352 {
353 
354  int result = 0;
355  DetectStreamSizeData *sd = NULL;
356  TcpSession ssn;
357  ThreadVars tv;
359  Packet *p = PacketGetFromAlloc();
360  if (unlikely(p == NULL))
361  return 0;
362  Signature s;
363  SigMatch sm;
364  TcpStream client;
365  Flow f;
366  IPV4Hdr ip4h;
367 
368  memset(&ssn, 0, sizeof(TcpSession));
369  memset(&tv, 0, sizeof(ThreadVars));
370  memset(&dtx, 0, sizeof(DetectEngineThreadCtx));
371  memset(&s, 0, sizeof(Signature));
372  memset(&sm, 0, sizeof(SigMatch));
373  memset(&client, 0, sizeof(TcpStream));
374  memset(&f, 0, sizeof(Flow));
375  memset(&ip4h, 0, sizeof(IPV4Hdr));
376 
377  sd = rs_detect_stream_size_parse(" client , > , 8 ");
378  if (sd != NULL) {
379  if (!(sd->flags & StreamSizeClient) && sd->du32.mode != DETECT_UINT_GT &&
380  sd->du32.arg1 != 8) {
381  SCFree(p);
382  return 0;
383  }
384  } else
385  {
386  SCFree(p);
387  return 0;
388  }
389 
390  client.next_seq = 20;
391  client.isn = 12;
392  ssn.client = client;
393  f.protoctx = &ssn;
394  p->flow = &f;
395  UTHSetIPV4Hdr(p, &ip4h);
396  sm.ctx = (SigMatchCtx*)sd;
397 
398  if (!DetectStreamSizeMatch(&dtx, p, &s, sm.ctx))
399  result = 1;
400 
401  SCFree(p);
402  return result;
403 }
404 
405 /**
406  * \brief this function registers unit tests for DetectStreamSize
407  */
408 void DetectStreamSizeRegisterTests(void)
409 {
410  UtRegisterTest("DetectStreamSizeParseTest01", DetectStreamSizeParseTest01);
411  UtRegisterTest("DetectStreamSizeParseTest02", DetectStreamSizeParseTest02);
412  UtRegisterTest("DetectStreamSizeParseTest03", DetectStreamSizeParseTest03);
413  UtRegisterTest("DetectStreamSizeParseTest04", DetectStreamSizeParseTest04);
414 }
415 #endif /* UNITTESTS */
util-byte.h
detect-engine-uint.h
SigTableElmt_::url
const char * url
Definition: detect.h:1304
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Definition: stream-tcp-private.h:106
TcpStream_::isn
uint32_t isn
Definition: stream-tcp-private.h:113
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struct SigMatch_ * smlists[DETECT_SM_LIST_MAX]
Definition: detect.h:586
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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:1303
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Definition: detect-parse.c:127
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Definition: detect.h:1291
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Definition: detect.h:1301
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Container for matching data for a signature group.
Definition: detect.h:1457
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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:360
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Definition: detect.h:1197
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void UTHSetIPV4Hdr(Packet *p, IPV4Hdr *ip4h)
Definition: util-unittest-helper.c:126
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Definition: detect.h:841
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@ DETECT_STREAM_SIZE
Definition: detect-engine-register.h:117
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uint8_t u8[16]
Definition: detect-engine-prefilter-common.h:24
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#define DETECT_UINT_GT
Definition: detect-engine-uint.h:32
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Definition: flow.h:450
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int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1286
util-unittest.h
util-unittest-helper.h
detect-stream_size.h
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int(* SetupPrefilter)(DetectEngineCtx *de_ctx, struct SigGroupHead_ *sgh)
Definition: detect.h:1289
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Definition: detect-engine-prefilter-common.h:35
util-debug.h
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Definition: fuzz_siginit.c:17
DetectEngineThreadCtx_
Definition: detect.h:1090
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#define SIG_MASK_REQUIRE_FLOW
Definition: detect.h:302
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uint32_t u32[4]
Definition: detect-engine-prefilter-common.h:26
detect.h
ThreadVars_
Per thread variable structure.
Definition: threadvars.h:57
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struct SigMatch_ * next
Definition: detect.h:353
DETECT_SM_LIST_MATCH
@ DETECT_SM_LIST_MATCH
Definition: detect.h:114
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Definition: detect.h:352
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Definition: decode.h:482
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:162
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SignatureInitData * init_data
Definition: detect.h:670
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int PrefilterSetupPacketHeader(DetectEngineCtx *de_ctx, SigGroupHead *sgh, int sm_type, SignatureMask mask, 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:404
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int(* Match)(DetectEngineThreadCtx *, Packet *, const Signature *, const SigMatchCtx *)
Definition: detect.h:1269
SigMatchCtx_
Used to start a pointer to SigMatch context Should never be dereferenced without casting to something...
Definition: detect.h:344
IPV4Hdr_
Definition: decode-ipv4.h:72
Packet_::flow
struct Flow_ * flow
Definition: decode.h:521
suricata-common.h
SigMatch_::type
uint16_t type
Definition: detect.h:350
TcpSession_::client
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Definition: stream-tcp-private.h:295
tv
ThreadVars * tv
Definition: fuzz_decodepcapfile.c:32
TcpStream_::next_seq
uint32_t next_seq
Definition: stream-tcp-private.h:114
PacketGetFromAlloc
Packet * PacketGetFromAlloc(void)
Get a malloced packet.
Definition: decode.c:232
TcpSession_::server
TcpStream server
Definition: stream-tcp-private.h:294
SCFree
#define SCFree(p)
Definition: util-mem.h:61
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bool(* SupportsPrefilter)(const Signature *s)
Definition: detect.h:1288
DetectStreamSizeRegister
void DetectStreamSizeRegister(void)
Registration function for stream_size: keyword.
Definition: detect-stream_size.c:58
detect-parse.h
Signature_
Signature container.
Definition: detect.h:601
SigMatch_
a single match condition for a signature
Definition: detect.h:349
PrefilterPacketHeaderValue
Definition: detect-engine-prefilter-common.h:23
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:436
detect-engine-prefilter-common.h
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Definition: stream-tcp-private.h:283
flow.h
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#define SCReturnInt(x)
Definition: util-debug.h:275
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Definition: decode-tcp.h:149
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void(* RegisterTests)(void)
Definition: detect.h:1293