suricata
detect-tos.c
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1 /* Copyright (C) 2007-2010 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 pcre *parse_regex;
49 static pcre_extra *parse_regex_study;
50 
51 static int DetectTosSetup(DetectEngineCtx *, Signature *, const char *);
52 static int DetectTosMatch(DetectEngineThreadCtx *, Packet *,
53  const Signature *, const SigMatchCtx *);
54 static void DetectTosRegisterTests(void);
55 static void DetectTosFree(void *);
56 
57 #define DETECT_IPTOS_MIN 0
58 #define DETECT_IPTOS_MAX 255
59 
60 /**
61  * \brief Register Tos keyword.
62  */
64 {
66  sigmatch_table[DETECT_TOS].Match = DetectTosMatch;
67  sigmatch_table[DETECT_TOS].Setup = DetectTosSetup;
68  sigmatch_table[DETECT_TOS].Free = DetectTosFree;
69  sigmatch_table[DETECT_TOS].RegisterTests = DetectTosRegisterTests;
73  DOC_URL DOC_VERSION "/rules/header-keywords.html#tos";
74 
75  DetectSetupParseRegexes(PARSE_REGEX, &parse_regex, &parse_regex_study);
76 }
77 
78 /**
79  * \brief Match function for tos keyword.
80  *
81  * \param tv ThreadVars instance.
82  * \param det_ctx Pointer to the detection thread ctx.
83  * \param p Pointer to the packet.
84  * \param m Pointer to the SigMatch containing the tos data.
85  *
86  * \retval 0 no match
87  * \retval 1 match
88  */
89 static int DetectTosMatch(DetectEngineThreadCtx *det_ctx, Packet *p,
90  const Signature *s, const SigMatchCtx *ctx)
91 {
92  const DetectTosData *tosd = (const DetectTosData *)ctx;
93  int result = 0;
94 
95  if (!PKT_IS_IPV4(p) || PKT_IS_PSEUDOPKT(p)) {
96  return 0;
97  }
98 
99  if (tosd->tos == IPV4_GET_IPTOS(p)) {
100  SCLogDebug("tos match found for %d\n", tosd->tos);
101  result = 1;
102  }
103 
104  return (tosd->negated ^ result);
105 }
106 
107 static DetectTosData *DetectTosParse(const char *arg, bool negate)
108 {
109  DetectTosData *tosd = NULL;
110 #define MAX_SUBSTRINGS 30
111  int ret = 0, res = 0;
112  int ov[MAX_SUBSTRINGS];
113 
114  ret = pcre_exec(parse_regex, parse_regex_study, arg, strlen(arg), 0, 0,
115  ov, MAX_SUBSTRINGS);
116 
117  if (ret != 2) {
118  SCLogError(SC_ERR_PCRE_MATCH, "invalid tos option - %s. "
119  "The tos option value must be in the range "
120  "%u - %u", arg, DETECT_IPTOS_MIN, DETECT_IPTOS_MAX);
121  goto error;
122  }
123 
124  /* For TOS value */
125  char tosbytes_str[64] = "";
126  res = pcre_copy_substring((char *)arg, ov, MAX_SUBSTRINGS, 1,
127  tosbytes_str, sizeof(tosbytes_str));
128  if (res < 0) {
129  SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_copy_substring failed");
130  goto error;
131  }
132 
133  int64_t tos = 0;
134 
135  if (tosbytes_str[0] == 'x' || tosbytes_str[0] == 'X') {
136  int r = ByteExtractStringSigned(&tos, 16, 0, &tosbytes_str[1]);
137  if (r < 0) {
138  goto error;
139  }
140  } else {
141  int r = ByteExtractStringSigned(&tos, 10, 0, &tosbytes_str[0]);
142  if (r < 0) {
143  goto error;
144  }
145  }
146 
147  if (!(tos >= DETECT_IPTOS_MIN && tos <= DETECT_IPTOS_MAX)) {
148  SCLogError(SC_ERR_INVALID_SIGNATURE, "Invalid tos argument - "
149  "%s. The tos option value must be in the range "
150  "%u - %u", tosbytes_str, DETECT_IPTOS_MIN, DETECT_IPTOS_MAX);
151  goto error;
152  }
153 
154  tosd = SCMalloc(sizeof(DetectTosData));
155  if (unlikely(tosd == NULL))
156  goto error;
157  tosd->tos = (uint8_t)tos;
158  tosd->negated = negate;
159 
160  return tosd;
161 
162 error:
163  return NULL;
164 }
165 
166 /**
167  * \brief Setup function for tos argument. Parse the argument and
168  * add it into the sig.
169  *
170  * \param de_ctx Detection Engine Context instance.
171  * \param s Pointer to the signature.
172  * \param arg Argument to be parsed.
173  *
174  * \retval 0 on Success.
175  * \retval -1 on Failure.
176  */
177 static int DetectTosSetup(DetectEngineCtx *de_ctx, Signature *s, const char *arg)
178 {
179  DetectTosData *tosd = DetectTosParse(arg, s->init_data->negated);
180  if (tosd == NULL)
181  return -1;
182 
183  SigMatch *sm = SigMatchAlloc();
184  if (sm == NULL) {
185  DetectTosFree(tosd);
186  return -1;
187  }
188 
189  sm->type = DETECT_TOS;
190  sm->ctx = (SigMatchCtx *)tosd;
191 
194  return 0;
195 }
196 
197 /**
198  * \brief Free data allocated by the tos keyword.
199  *
200  * \param tosd Data to be freed.
201  */
202 static void DetectTosFree(void *tosd)
203 {
204  SCFree(tosd);
205 }
206 
207 /********************************Unittests***********************************/
208 
209 #ifdef UNITTESTS
210 
211 static int DetectTosTest01(void)
212 {
213  DetectTosData *tosd = NULL;
214  tosd = DetectTosParse("12", false);
215  if (tosd != NULL && tosd->tos == 12 && !tosd->negated) {
216  DetectTosFree(tosd);
217  return 1;
218  }
219 
220  return 0;
221 }
222 
223 static int DetectTosTest02(void)
224 {
225  DetectTosData *tosd = NULL;
226  tosd = DetectTosParse("123", false);
227  if (tosd != NULL && tosd->tos == 123 && !tosd->negated) {
228  DetectTosFree(tosd);
229  return 1;
230  }
231 
232  return 0;
233 }
234 
235 static int DetectTosTest04(void)
236 {
237  DetectTosData *tosd = NULL;
238  tosd = DetectTosParse("256", false);
239  if (tosd != NULL) {
240  DetectTosFree(tosd);
241  return 0;
242  }
243 
244  return 1;
245 }
246 
247 static int DetectTosTest05(void)
248 {
249  DetectTosData *tosd = NULL;
250  tosd = DetectTosParse("boom", false);
251  if (tosd != NULL) {
252  DetectTosFree(tosd);
253  return 0;
254  }
255 
256  return 1;
257 }
258 
259 static int DetectTosTest06(void)
260 {
261  DetectTosData *tosd = NULL;
262  tosd = DetectTosParse("x12", false);
263  if (tosd != NULL && tosd->tos == 0x12 && !tosd->negated) {
264  DetectTosFree(tosd);
265  return 1;
266  }
267 
268  return 0;
269 }
270 
271 static int DetectTosTest07(void)
272 {
273  DetectTosData *tosd = NULL;
274  tosd = DetectTosParse("X12", false);
275  if (tosd != NULL && tosd->tos == 0x12 && !tosd->negated) {
276  DetectTosFree(tosd);
277  return 1;
278  }
279 
280  return 0;
281 }
282 
283 static int DetectTosTest08(void)
284 {
285  DetectTosData *tosd = NULL;
286  tosd = DetectTosParse("x121", false);
287  if (tosd != NULL) {
288  DetectTosFree(tosd);
289  return 0;
290  }
291 
292  return 1;
293 }
294 
295 static int DetectTosTest09(void)
296 {
297  DetectTosData *tosd = NULL;
298  tosd = DetectTosParse("12", true);
299  if (tosd != NULL && tosd->tos == 12 && tosd->negated) {
300  DetectTosFree(tosd);
301  return 1;
302  }
303 
304  return 0;
305 }
306 
307 static int DetectTosTest10(void)
308 {
309  DetectTosData *tosd = NULL;
310  tosd = DetectTosParse("x12", true);
311  if (tosd != NULL && tosd->tos == 0x12 && tosd->negated) {
312  DetectTosFree(tosd);
313  return 1;
314  }
315 
316  return 0;
317 }
318 
319 static int DetectTosTest12(void)
320 {
321  int result = 0;
322  uint8_t *buf = (uint8_t *)"Hi all!";
323  uint16_t buflen = strlen((char *)buf);
324  Packet *p;
325 
326  p = UTHBuildPacket((uint8_t *)buf, buflen, IPPROTO_TCP);
327 
328  if (p == NULL)
329  goto end;
330 
331  IPV4_SET_RAW_IPTOS(p->ip4h, 10);
332 
333  const char *sigs[4];
334  sigs[0]= "alert ip any any -> any any (msg:\"Testing id 1\"; tos: 10 ; sid:1;)";
335  sigs[1]= "alert ip any any -> any any (msg:\"Testing id 2\"; tos: ! 10; sid:2;)";
336  sigs[2]= "alert ip any any -> any any (msg:\"Testing id 3\"; tos:20 ; sid:3;)";
337  sigs[3]= "alert ip any any -> any any (msg:\"Testing id 3\"; tos:! 20; sid:4;)";
338 
339  uint32_t sid[4] = {1, 2, 3, 4};
340 
341  uint32_t results[1][4] =
342  {
343  {1, 0, 0, 1},
344  };
345 
346  result = UTHGenericTest(&p, 1, sigs, sid, (uint32_t *) results, 4);
347 
348  UTHFreePackets(&p, 1);
349 
350 end:
351  return result;
352 }
353 
354 #endif
355 
356 void DetectTosRegisterTests(void)
357 {
358 #ifdef UNITTESTS
359  UtRegisterTest("DetectTosTest01", DetectTosTest01);
360  UtRegisterTest("DetectTosTest02", DetectTosTest02);
361  UtRegisterTest("DetectTosTest04", DetectTosTest04);
362  UtRegisterTest("DetectTosTest05", DetectTosTest05);
363  UtRegisterTest("DetectTosTest06", DetectTosTest06);
364  UtRegisterTest("DetectTosTest07", DetectTosTest07);
365  UtRegisterTest("DetectTosTest08", DetectTosTest08);
366  UtRegisterTest("DetectTosTest09", DetectTosTest09);
367  UtRegisterTest("DetectTosTest10", DetectTosTest10);
368  UtRegisterTest("DetectTosTest12", DetectTosTest12);
369 #endif
370  return;
371 }
uint8_t tos
Definition: detect-tos.h:29
SigTableElmt sigmatch_table[DETECT_TBLSIZE]
Definition: detect.h:1439
SignatureInitData * init_data
Definition: detect.h:586
int(* Setup)(DetectEngineCtx *, Signature *, const char *)
Definition: detect.h:1179
#define SCLogDebug(...)
Definition: util-debug.h:335
uint32_t flags
Definition: detect.h:518
#define MAX_SUBSTRINGS
#define unlikely(expr)
Definition: util-optimize.h:35
#define SIG_FLAG_REQUIRE_PACKET
Definition: detect.h:219
const char * name
Definition: detect.h:1193
Signature container.
Definition: detect.h:517
Used to start a pointer to SigMatch context Should never be dereferenced without casting to something...
Definition: detect.h:308
#define PKT_IS_IPV4(p)
Definition: decode.h:251
main detection engine ctx
Definition: detect.h:756
#define DETECT_IPTOS_MAX
Definition: detect-tos.c:58
Data structures and function prototypes for keeping state for the detection engine.
void(* Free)(void *)
Definition: detect.h:1184
#define SCLogError(err_code,...)
Macro used to log ERROR messages.
Definition: util-debug.h:294
int ByteExtractStringSigned(int64_t *res, int base, uint16_t len, const char *str)
Definition: util-byte.c:304
void UtRegisterTest(const char *name, int(*TestFn)(void))
Register unit test.
void DetectSetupParseRegexes(const char *parse_str, pcre **parse_regex, pcre_extra **parse_regex_study)
#define SIGMATCH_QUOTES_OPTIONAL
Definition: detect.h:1374
uint8_t negated
Definition: detect-tos.h:28
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.
#define DETECT_IPTOS_MIN
Definition: detect-tos.c:57
int(* Match)(DetectEngineThreadCtx *, Packet *, const Signature *, const SigMatchCtx *)
Definition: detect.h:1163
uint8_t type
Definition: detect.h:314
void SigMatchAppendSMToList(Signature *s, SigMatch *new, int list)
Append a SigMatch to the list type.
Definition: detect-parse.c:288
IPV4Hdr * ip4h
Definition: decode.h:500
#define IPV4_SET_RAW_IPTOS(ip4h, value)
Definition: decode-ipv4.h:113
void DetectTosRegister(void)
Register Tos keyword.
Definition: detect-tos.c:63
SigMatchCtx * ctx
Definition: detect.h:316
#define SCMalloc(a)
Definition: util-mem.h:222
#define SCFree(a)
Definition: util-mem.h:322
PoolThreadReserved res
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...
const char * url
Definition: detect.h:1196
#define IPV4_GET_IPTOS(p)
Definition: decode-ipv4.h:125
#define DOC_URL
Definition: suricata.h:86
#define PKT_IS_PSEUDOPKT(p)
return 1 if the packet is a pseudo packet
Definition: decode.h:1129
SigMatch * SigMatchAlloc(void)
Definition: detect-parse.c:232
#define SIGMATCH_HANDLE_NEGATION
Definition: detect.h:1382
#define DOC_VERSION
Definition: suricata.h:91
uint16_t flags
Definition: detect.h:1187
#define PARSE_REGEX
Definition: detect-tos.c:46
void UTHFreePackets(Packet **p, int numpkts)
UTHFreePackets: function to release the allocated data from UTHBuildPacket and the packet itself...
void(* RegisterTests)(void)
Definition: detect.h:1185
a single match condition for a signature
Definition: detect.h:313