suricata
detect-tos.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 Anoop Saldanha <anoopsaldanha@gmail.com>
22  */
23 
24 #include "suricata-common.h"
25 #include "threads.h"
26 #include "decode.h"
27 
28 #include "detect.h"
29 #include "detect-parse.h"
30 #include "detect-engine.h"
31 #include "detect-engine-mpm.h"
32 #include "detect-engine-state.h"
33 #include "detect-tos.h"
34 
35 #include "app-layer-protos.h"
36 
37 #include "flow.h"
38 #include "flow-var.h"
39 #include "flow-util.h"
40 
41 #include "util-byte.h"
42 #include "util-debug.h"
43 #include "util-unittest.h"
44 #include "util-unittest-helper.h"
45 
46 #define PARSE_REGEX "^\\s*(!?\\s*[0-9]{1,3}|!?\\s*[xX][0-9a-fA-F]{1,2})\\s*$"
47 
48 static DetectParseRegex parse_regex;
49 
50 static int DetectTosSetup(DetectEngineCtx *, Signature *, const char *);
51 static int DetectTosMatch(DetectEngineThreadCtx *, Packet *,
52  const Signature *, const SigMatchCtx *);
53 #ifdef UNITTESTS
54 static void DetectTosRegisterTests(void);
55 #endif
56 static void DetectTosFree(DetectEngineCtx *, void *);
57 
58 #define DETECT_IPTOS_MIN 0
59 #define DETECT_IPTOS_MAX 255
60 
61 /**
62  * \brief Register Tos keyword.
63  */
65 {
67  sigmatch_table[DETECT_TOS].desc = "match on specific decimal values of the IP header TOS field";
68  sigmatch_table[DETECT_TOS].Match = DetectTosMatch;
69  sigmatch_table[DETECT_TOS].Setup = DetectTosSetup;
70  sigmatch_table[DETECT_TOS].Free = DetectTosFree;
71 #ifdef UNITTESTS
72  sigmatch_table[DETECT_TOS].RegisterTests = DetectTosRegisterTests;
73 #endif
77  "/rules/header-keywords.html#tos";
78 
79  DetectSetupParseRegexes(PARSE_REGEX, &parse_regex);
80 }
81 
82 /**
83  * \brief Match function for tos keyword.
84  *
85  * \param tv ThreadVars instance.
86  * \param det_ctx Pointer to the detection thread ctx.
87  * \param p Pointer to the packet.
88  * \param m Pointer to the SigMatch containing the tos data.
89  *
90  * \retval 0 no match
91  * \retval 1 match
92  */
93 static int DetectTosMatch(DetectEngineThreadCtx *det_ctx, Packet *p,
94  const Signature *s, const SigMatchCtx *ctx)
95 {
96  const DetectTosData *tosd = (const DetectTosData *)ctx;
97  int result = 0;
98 
99  if (!PKT_IS_IPV4(p) || PKT_IS_PSEUDOPKT(p)) {
100  return 0;
101  }
102 
103  if (tosd->tos == IPV4_GET_IPTOS(p)) {
104  SCLogDebug("tos match found for %d\n", tosd->tos);
105  result = 1;
106  }
107 
108  return (tosd->negated ^ result);
109 }
110 
111 static DetectTosData *DetectTosParse(const char *arg, bool negate)
112 {
113  DetectTosData *tosd = NULL;
114  int ret = 0, res = 0;
115  int ov[MAX_SUBSTRINGS];
116 
117  ret = DetectParsePcreExec(&parse_regex, arg, 0, 0, ov, MAX_SUBSTRINGS);
118  if (ret != 2) {
119  SCLogError(SC_ERR_PCRE_MATCH, "invalid tos option - %s. "
120  "The tos option value must be in the range "
121  "%u - %u", arg, DETECT_IPTOS_MIN, DETECT_IPTOS_MAX);
122  goto error;
123  }
124 
125  /* For TOS value */
126  char tosbytes_str[64] = "";
127  res = pcre_copy_substring((char *)arg, ov, MAX_SUBSTRINGS, 1,
128  tosbytes_str, sizeof(tosbytes_str));
129  if (res < 0) {
130  SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_copy_substring failed");
131  goto error;
132  }
133 
134  int64_t tos = 0;
135 
136  if (tosbytes_str[0] == 'x' || tosbytes_str[0] == 'X') {
137  if (StringParseInt64(&tos, 16, 0, &tosbytes_str[1]) < 0) {
138  goto error;
139  }
140  } else {
141  if (StringParseInt64(&tos, 10, 0, &tosbytes_str[0]) < 0) {
142  goto error;
143  }
144  }
145 
146  if (!(tos >= DETECT_IPTOS_MIN && tos <= DETECT_IPTOS_MAX)) {
147  SCLogError(SC_ERR_INVALID_SIGNATURE, "Invalid tos argument - "
148  "%s. The tos option value must be in the range "
149  "%u - %u", tosbytes_str, DETECT_IPTOS_MIN, DETECT_IPTOS_MAX);
150  goto error;
151  }
152 
153  tosd = SCMalloc(sizeof(DetectTosData));
154  if (unlikely(tosd == NULL))
155  goto error;
156  tosd->tos = (uint8_t)tos;
157  tosd->negated = negate;
158 
159  return tosd;
160 
161 error:
162  return NULL;
163 }
164 
165 /**
166  * \brief Setup function for tos argument. Parse the argument and
167  * add it into the sig.
168  *
169  * \param de_ctx Detection Engine Context instance.
170  * \param s Pointer to the signature.
171  * \param arg Argument to be parsed.
172  *
173  * \retval 0 on Success.
174  * \retval -1 on Failure.
175  */
176 static int DetectTosSetup(DetectEngineCtx *de_ctx, Signature *s, const char *arg)
177 {
178  DetectTosData *tosd = DetectTosParse(arg, s->init_data->negated);
179  if (tosd == NULL)
180  return -1;
181 
182  SigMatch *sm = SigMatchAlloc();
183  if (sm == NULL) {
184  DetectTosFree(de_ctx, tosd);
185  return -1;
186  }
187 
188  sm->type = DETECT_TOS;
189  sm->ctx = (SigMatchCtx *)tosd;
190 
193  return 0;
194 }
195 
196 /**
197  * \brief Free data allocated by the tos keyword.
198  *
199  * \param tosd Data to be freed.
200  */
201 static void DetectTosFree(DetectEngineCtx *de_ctx, void *tosd)
202 {
203  SCFree(tosd);
204 }
205 
206 /********************************Unittests***********************************/
207 
208 #ifdef UNITTESTS
209 
210 static int DetectTosTest01(void)
211 {
212  DetectTosData *tosd = NULL;
213  tosd = DetectTosParse("12", false);
214  if (tosd != NULL && tosd->tos == 12 && !tosd->negated) {
215  DetectTosFree(NULL, tosd);
216  return 1;
217  }
218 
219  return 0;
220 }
221 
222 static int DetectTosTest02(void)
223 {
224  DetectTosData *tosd = NULL;
225  tosd = DetectTosParse("123", false);
226  if (tosd != NULL && tosd->tos == 123 && !tosd->negated) {
227  DetectTosFree(NULL, tosd);
228  return 1;
229  }
230 
231  return 0;
232 }
233 
234 static int DetectTosTest04(void)
235 {
236  DetectTosData *tosd = NULL;
237  tosd = DetectTosParse("256", false);
238  if (tosd != NULL) {
239  DetectTosFree(NULL, tosd);
240  return 0;
241  }
242 
243  return 1;
244 }
245 
246 static int DetectTosTest05(void)
247 {
248  DetectTosData *tosd = NULL;
249  tosd = DetectTosParse("boom", false);
250  if (tosd != NULL) {
251  DetectTosFree(NULL, tosd);
252  return 0;
253  }
254 
255  return 1;
256 }
257 
258 static int DetectTosTest06(void)
259 {
260  DetectTosData *tosd = NULL;
261  tosd = DetectTosParse("x12", false);
262  if (tosd != NULL && tosd->tos == 0x12 && !tosd->negated) {
263  DetectTosFree(NULL, tosd);
264  return 1;
265  }
266 
267  return 0;
268 }
269 
270 static int DetectTosTest07(void)
271 {
272  DetectTosData *tosd = NULL;
273  tosd = DetectTosParse("X12", false);
274  if (tosd != NULL && tosd->tos == 0x12 && !tosd->negated) {
275  DetectTosFree(NULL, tosd);
276  return 1;
277  }
278 
279  return 0;
280 }
281 
282 static int DetectTosTest08(void)
283 {
284  DetectTosData *tosd = NULL;
285  tosd = DetectTosParse("x121", false);
286  if (tosd != NULL) {
287  DetectTosFree(NULL, tosd);
288  return 0;
289  }
290 
291  return 1;
292 }
293 
294 static int DetectTosTest09(void)
295 {
296  DetectTosData *tosd = NULL;
297  tosd = DetectTosParse("12", true);
298  if (tosd != NULL && tosd->tos == 12 && tosd->negated) {
299  DetectTosFree(NULL, tosd);
300  return 1;
301  }
302 
303  return 0;
304 }
305 
306 static int DetectTosTest10(void)
307 {
308  DetectTosData *tosd = NULL;
309  tosd = DetectTosParse("x12", true);
310  if (tosd != NULL && tosd->tos == 0x12 && tosd->negated) {
311  DetectTosFree(NULL, tosd);
312  return 1;
313  }
314 
315  return 0;
316 }
317 
318 static int DetectTosTest12(void)
319 {
320  int result = 0;
321  uint8_t *buf = (uint8_t *)"Hi all!";
322  uint16_t buflen = strlen((char *)buf);
323  Packet *p;
324 
325  p = UTHBuildPacket((uint8_t *)buf, buflen, IPPROTO_TCP);
326 
327  if (p == NULL)
328  goto end;
329 
330  IPV4_SET_RAW_IPTOS(p->ip4h, 10);
331 
332  const char *sigs[4];
333  sigs[0]= "alert ip any any -> any any (msg:\"Testing id 1\"; tos: 10 ; sid:1;)";
334  sigs[1]= "alert ip any any -> any any (msg:\"Testing id 2\"; tos: ! 10; sid:2;)";
335  sigs[2]= "alert ip any any -> any any (msg:\"Testing id 3\"; tos:20 ; sid:3;)";
336  sigs[3]= "alert ip any any -> any any (msg:\"Testing id 3\"; tos:! 20; sid:4;)";
337 
338  uint32_t sid[4] = {1, 2, 3, 4};
339 
340  uint32_t results[1][4] =
341  {
342  {1, 0, 0, 1},
343  };
344 
345  result = UTHGenericTest(&p, 1, sigs, sid, (uint32_t *) results, 4);
346 
347  UTHFreePackets(&p, 1);
348 
349 end:
350  return result;
351 }
352 
353 void DetectTosRegisterTests(void)
354 {
355  UtRegisterTest("DetectTosTest01", DetectTosTest01);
356  UtRegisterTest("DetectTosTest02", DetectTosTest02);
357  UtRegisterTest("DetectTosTest04", DetectTosTest04);
358  UtRegisterTest("DetectTosTest05", DetectTosTest05);
359  UtRegisterTest("DetectTosTest06", DetectTosTest06);
360  UtRegisterTest("DetectTosTest07", DetectTosTest07);
361  UtRegisterTest("DetectTosTest08", DetectTosTest08);
362  UtRegisterTest("DetectTosTest09", DetectTosTest09);
363  UtRegisterTest("DetectTosTest10", DetectTosTest10);
364  UtRegisterTest("DetectTosTest12", DetectTosTest12);
365  return;
366 }
367 #endif
util-byte.h
SigTableElmt_::url
const char * url
Definition: detect.h:1214
detect-engine.h
PARSE_REGEX
#define PARSE_REGEX
Definition: detect-tos.c:46
SigTableElmt_::desc
const char * desc
Definition: detect.h:1213
SigTableElmt_::Free
void(* Free)(DetectEngineCtx *, void *)
Definition: detect.h:1201
flow-util.h
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
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
SIGMATCH_QUOTES_OPTIONAL
#define SIGMATCH_QUOTES_OPTIONAL
Definition: detect.h:1392
threads.h
results
struct DetectRfbSecresult_ results[]
SigTableElmt_::flags
uint16_t flags
Definition: detect.h:1205
DetectEngineCtx_
main detection engine ctx
Definition: detect.h:767
SC_ERR_INVALID_SIGNATURE
@ SC_ERR_INVALID_SIGNATURE
Definition: util-error.h:69
DETECT_IPTOS_MAX
#define DETECT_IPTOS_MAX
Definition: detect-tos.c:59
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
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
util-unittest.h
util-unittest-helper.h
decode.h
util-debug.h
SC_ERR_PCRE_MATCH
@ SC_ERR_PCRE_MATCH
Definition: util-error.h:32
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
detect-tos.h
detect-engine-mpm.h
detect.h
DETECT_SM_LIST_MATCH
@ DETECT_SM_LIST_MATCH
Definition: detect.h:89
SigMatch_::ctx
SigMatchCtx * ctx
Definition: detect.h:323
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_IPTOS_MIN
#define DETECT_IPTOS_MIN
Definition: detect-tos.c:58
Packet_::ip4h
IPV4Hdr * ip4h
Definition: decode.h:509
SIGMATCH_HANDLE_NEGATION
#define SIGMATCH_HANDLE_NEGATION
Definition: detect.h:1400
Signature_::init_data
SignatureInitData * init_data
Definition: detect.h:597
detect-engine-state.h
Data structures and function prototypes for keeping state for the detection engine.
SignatureInitData_::negated
bool negated
Definition: detect.h:485
SigTableElmt_::Match
int(* Match)(DetectEngineThreadCtx *, Packet *, const Signature *, const SigMatchCtx *)
Definition: detect.h:1179
SigMatchAlloc
SigMatch * SigMatchAlloc(void)
Definition: detect-parse.c:235
IPV4_SET_RAW_IPTOS
#define IPV4_SET_RAW_IPTOS(ip4h, value)
Definition: decode-ipv4.h:113
SigMatch_::type
uint8_t type
Definition: detect.h:321
SigMatchCtx_
Used to start a pointer to SigMatch context Should never be dereferenced without casting to something...
Definition: detect.h:315
DetectTosData_::negated
uint8_t negated
Definition: detect-tos.h:28
StringParseInt64
int StringParseInt64(int64_t *res, int base, uint16_t len, const char *str)
Definition: util-byte.c:608
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
DetectTosRegister
void DetectTosRegister(void)
Register Tos keyword.
Definition: detect-tos.c:64
SCMalloc
#define SCMalloc(sz)
Definition: util-mem.h:47
IPV4_GET_IPTOS
#define IPV4_GET_IPTOS(p)
Definition: decode-ipv4.h:125
SCFree
#define SCFree(p)
Definition: util-mem.h:61
detect-parse.h
Signature_
Signature container.
Definition: detect.h:528
SigMatch_
a single match condition for a signature
Definition: detect.h:320
DETECT_TOS
@ DETECT_TOS
Definition: detect-engine-register.h:44
app-layer-protos.h
flow.h
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
SigTableElmt_::RegisterTests
void(* RegisterTests)(void)
Definition: detect.h:1203
DetectTosData_::tos
uint8_t tos
Definition: detect-tos.h:29
DetectTosData_
Definition: detect-tos.h:27
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