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suricata/src/detect-dsize.c

826 lines
20 KiB
C

/* Copyright (C) 2007-2010 Open Information Security Foundation
*
* You can copy, redistribute or modify this Program under the terms of
* the GNU General Public License version 2 as published by the Free
* Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
/**
* \file
*
* \author Victor Julien <victor@inliniac.net>
*
* Implements the dsize keyword
*/
#include "suricata-common.h"
#include "decode.h"
#include "detect.h"
#include "detect-parse.h"
#include "flow-var.h"
#include "detect-dsize.h"
#include "util-unittest.h"
#include "util-debug.h"
#include "util-byte.h"
/**
* dsize:[<>]<0-65535>[<><0-65535>];
*/
#define PARSE_REGEX "^\\s*(<|>)?\\s*([0-9]{1,5})\\s*(?:(<>)\\s*([0-9]{1,5}))?\\s*$"
static pcre *parse_regex;
static pcre_extra *parse_regex_study;
int DetectDsizeMatch (ThreadVars *, DetectEngineThreadCtx *, Packet *, Signature *, SigMatch *);
static int DetectDsizeSetup (DetectEngineCtx *, Signature *s, char *str);
void DsizeRegisterTests(void);
static void DetectDsizeFree(void *);
/**
* \brief Registration function for dsize: keyword
*/
void DetectDsizeRegister (void) {
sigmatch_table[DETECT_DSIZE].name = "dsize";
sigmatch_table[DETECT_DSIZE].Match = DetectDsizeMatch;
sigmatch_table[DETECT_DSIZE].Setup = DetectDsizeSetup;
sigmatch_table[DETECT_DSIZE].Free = DetectDsizeFree;
sigmatch_table[DETECT_DSIZE].RegisterTests = DsizeRegisterTests;
const char *eb;
int eo;
int opts = 0;
parse_regex = pcre_compile(PARSE_REGEX, opts, &eb, &eo, NULL);
if(parse_regex == NULL)
{
SCLogError(SC_ERR_PCRE_COMPILE,"pcre compile of \"%s\" failed at offset %" PRId32 ": %s", PARSE_REGEX, eo, eb);
goto error;
}
parse_regex_study = pcre_study(parse_regex, 0, &eb);
if(eb != NULL)
{
SCLogError(SC_ERR_PCRE_STUDY,"pcre study failed: %s", eb);
goto error;
}
return;
error:
/* XXX */
return;
}
/**
* \internal
* \brief This function is used to match flags on a packet with those passed via dsize:
*
* \param t pointer to thread vars
* \param det_ctx pointer to the pattern matcher thread
* \param p pointer to the current packet
* \param s pointer to the Signature
* \param m pointer to the sigmatch
*
* \retval 0 no match
* \retval 1 match
*/
int DetectDsizeMatch (ThreadVars *t, DetectEngineThreadCtx *det_ctx, Packet *p, Signature *s, SigMatch *m)
{
SCEnter();
int ret = 0;
if (PKT_IS_PSEUDOPKT(p)) {
SCReturnInt(0);
}
DetectDsizeData *dd = (DetectDsizeData *)m->ctx;
SCLogDebug("p->payload_len %"PRIu16"", p->payload_len);
if (dd->mode == DETECTDSIZE_EQ && dd->dsize == p->payload_len)
ret = 1;
else if (dd->mode == DETECTDSIZE_LT && p->payload_len < dd->dsize)
ret = 1;
else if (dd->mode == DETECTDSIZE_GT && p->payload_len > dd->dsize)
ret = 1;
else if (dd->mode == DETECTDSIZE_RA && p->payload_len > dd->dsize && p->payload_len < dd->dsize2)
ret = 1;
SCReturnInt(ret);
}
/**
* \internal
* \brief This function is used to parse dsize options passed via dsize: keyword
*
* \param rawstr Pointer to the user provided dsize options
*
* \retval dd pointer to DetectDsizeData on success
* \retval NULL on failure
*/
DetectDsizeData *DetectDsizeParse (char *rawstr)
{
DetectDsizeData *dd = NULL;
char *value1 = NULL, *value2 = NULL,
*mode = NULL, *range = NULL;
#define MAX_SUBSTRINGS 30
int ret = 0, res = 0;
int ov[MAX_SUBSTRINGS];
ret = pcre_exec(parse_regex, parse_regex_study, rawstr, strlen(rawstr), 0, 0, ov, MAX_SUBSTRINGS);
if (ret < 3 || ret > 5) {
SCLogError(SC_ERR_PCRE_MATCH,"Parse error %s", rawstr);
goto error;
}
const char *str_ptr;
res = pcre_get_substring((char *)rawstr, ov, MAX_SUBSTRINGS, 1, &str_ptr);
if (res < 0) {
SCLogError(SC_ERR_PCRE_GET_SUBSTRING,"pcre_get_substring failed");
goto error;
}
mode = (char *)str_ptr;
SCLogDebug("mode \"%s\"", mode);
if (ret >= 3) {
res = pcre_get_substring((char *)rawstr, ov, MAX_SUBSTRINGS, 2, &str_ptr);
if (res < 0) {
SCLogError(SC_ERR_PCRE_GET_SUBSTRING,"pcre_get_substring failed");
goto error;
}
value1 = (char *)str_ptr;
SCLogDebug("value1 \"%s\"", value1);
if (ret >= 4) {
res = pcre_get_substring((char *)rawstr, ov, MAX_SUBSTRINGS, 3, &str_ptr);
if (res < 0) {
SCLogError(SC_ERR_PCRE_GET_SUBSTRING,"pcre_get_substring failed");
goto error;
}
range = (char *)str_ptr;
SCLogDebug("range \"%s\"", range);
if (ret >= 5) {
res = pcre_get_substring((char *)rawstr, ov, MAX_SUBSTRINGS, 4, &str_ptr);
if (res < 0) {
SCLogError(SC_ERR_PCRE_GET_SUBSTRING,"pcre_get_substring failed");
goto error;
}
value2 = (char *)str_ptr;
SCLogDebug("value2 \"%s\"", value2);
}
}
}
dd = SCMalloc(sizeof(DetectDsizeData));
if (dd == NULL)
goto error;
dd->dsize = 0;
dd->dsize2 = 0;
dd->mode = DETECTDSIZE_EQ; // default
if (mode != NULL) {
if (mode[0] == '<')
dd->mode = DETECTDSIZE_LT;
else if (mode[0] == '>')
dd->mode = DETECTDSIZE_GT;
else
dd->mode = DETECTDSIZE_EQ;
}
if (range != NULL && strcmp("<>", range) == 0) {
if (mode != NULL && strlen(mode) != 0) {
SCLogError(SC_ERR_INVALID_ARGUMENT,"Range specified but mode also set");
goto error;
}
dd->mode = DETECTDSIZE_RA;
}
/** set the first dsize value */
if (ByteExtractStringUint16(&dd->dsize,10,strlen(value1),value1) <= 0) {
SCLogError(SC_ERR_INVALID_ARGUMENT, "Invalid size value1:\"%s\"", value1);
goto error;
}
/** set the second dsize value if specified */
if (value2 != NULL && strlen(value2) > 0) {
if (dd->mode != DETECTDSIZE_RA) {
SCLogError(SC_ERR_INVALID_ARGUMENT,"Multiple dsize values specified but mode is not range");
goto error;
}
if (ByteExtractStringUint16(&dd->dsize2,10,strlen(value2),value2) <= 0) {
SCLogError(SC_ERR_INVALID_ARGUMENT,"Invalid size value2:\"%s\"",value2);
goto error;
}
if (dd->dsize2 <= dd->dsize) {
SCLogError(SC_ERR_INVALID_ARGUMENT,"dsize2:%"PRIu16" <= dsize:%"PRIu16"",dd->dsize2,dd->dsize);
goto error;
}
}
SCLogDebug("dsize parsed succesfully dsize: %"PRIu16" dsize2: %"PRIu16"",dd->dsize,dd->dsize2);
if (value1)
SCFree(value1);
if (value2)
SCFree(value2);
if (mode)
SCFree(mode);
if (range)
SCFree(range);
return dd;
error:
if (dd)
SCFree(dd);
if (value1)
SCFree(value1);
if (value2)
SCFree(value2);
if (mode)
SCFree(mode);
if (range)
SCFree(range);
return NULL;
}
/**
* \internal
* \brief this function is used to add the parsed dsize into the current signature
*
* \param de_ctx pointer to the Detection Engine Context
* \param s pointer to the Current Signature
* \param rawstr pointer to the user provided flags options
*
* \retval 0 on Success
* \retval -1 on Failure
*/
static int DetectDsizeSetup (DetectEngineCtx *de_ctx, Signature *s, char *rawstr)
{
DetectDsizeData *dd = NULL;
SigMatch *sm = NULL;
if (SigMatchGetLastSM(s->sm_lists_tail[DETECT_SM_LIST_MATCH],
DETECT_DSIZE) != NULL) {
SCLogError(SC_ERR_INVALID_SIGNATURE, "Can't use 2 or more dsizes in "
"the same sig. Invalidating signature.");
goto error;
}
SCLogDebug("\'%s\'", rawstr);
dd = DetectDsizeParse(rawstr);
if (dd == NULL) {
SCLogError(SC_ERR_INVALID_ARGUMENT,"Parsing \'%s\' failed", rawstr);
goto error;
}
/* Okay so far so good, lets get this into a SigMatch
* and put it in the Signature. */
sm = SigMatchAlloc();
if (sm == NULL){
SCLogError(SC_ERR_MEM_ALLOC, "Failed to allocate memory for SigMatch");
SCFree(dd);
goto error;
}
sm->type = DETECT_DSIZE;
sm->ctx = (void *)dd;
SigMatchAppendPacket(s, sm);
SCLogDebug("dd->dsize %"PRIu16", dd->dsize2 %"PRIu16", dd->mode %"PRIu8"",
dd->dsize, dd->dsize2, dd->mode);
/* tell the sig it has a dsize to speed up engine init */
s->flags |= SIG_FLAG_REQUIRE_PACKET;
return 0;
error:
return -1;
}
/**
* \internal
* \brief this function will free memory associated with DetectDsizeData
*
* \param de pointer to DetectDsizeData
*/
void DetectDsizeFree(void *de_ptr) {
DetectDsizeData *dd = (DetectDsizeData *)de_ptr;
if(dd) SCFree(dd);
}
/*
* ONLY TESTS BELOW THIS COMMENT
*/
#ifdef UNITTESTS
#include "detect.h"
#include "detect-engine.h"
/**
* \test this is a test for a valid dsize value 1
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse01 (void) {
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse("1");
if (dd) {
DetectDsizeFree(dd);
return 1;
}
return 0;
}
/**
* \test this is a test for a valid dsize value >10
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse02 (void) {
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse(">10");
if (dd) {
DetectDsizeFree(dd);
return 1;
}
return 0;
}
/**
* \test this is a test for a valid dsize value <100
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse03 (void) {
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse("<100");
if (dd) {
DetectDsizeFree(dd);
return 1;
}
return 0;
}
/**
* \test this is a test for a valid dsize value 1<>2
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse04 (void) {
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse("1<>2");
if (dd) {
DetectDsizeFree(dd);
return 1;
}
return 0;
}
/**
* \test this is a test for a valid dsize value 1
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse05 (void) {
int result = 0;
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse("1");
if (dd) {
if (dd->dsize == 1)
result = 1;
DetectDsizeFree(dd);
}
return result;
}
/**
* \test this is a test for a valid dsize value >10
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse06 (void) {
int result = 0;
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse(">10");
if (dd) {
if (dd->dsize == 10 && dd->mode == DETECTDSIZE_GT)
result = 1;
DetectDsizeFree(dd);
}
return result;
}
/**
* \test this is a test for a valid dsize value <100
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse07 (void) {
int result = 0;
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse("<100");
if (dd) {
if (dd->dsize == 100 && dd->mode == DETECTDSIZE_LT)
result = 1;
DetectDsizeFree(dd);
}
return result;
}
/**
* \test this is a test for a valid dsize value 1<>2
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse08 (void) {
int result = 0;
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse("1<>2");
if (dd) {
if (dd->dsize == 1 && dd->dsize2 == 2 && dd->mode == DETECTDSIZE_RA)
result = 1;
DetectDsizeFree(dd);
}
return result;
}
/**
* \test this is a test for a invalid dsize value A
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse09 (void) {
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse("A");
if (dd) {
DetectDsizeFree(dd);
return 0;
}
return 1;
}
/**
* \test this is a test for a invalid dsize value >10<>10
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse10 (void) {
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse(">10<>10");
if (dd) {
DetectDsizeFree(dd);
return 0;
}
return 1;
}
/**
* \test this is a test for a invalid dsize value <>10
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse11 (void) {
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse("<>10");
if (dd) {
DetectDsizeFree(dd);
return 0;
}
return 1;
}
/**
* \test this is a test for a invalid dsize value 1<>
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse12 (void) {
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse("1<>");
if (dd) {
DetectDsizeFree(dd);
return 0;
}
return 1;
}
/**
* \test this is a test for a valid dsize value 1
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse13 (void) {
int result = 0;
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse("1");
if (dd) {
if (dd->dsize2 == 0)
result = 1;
DetectDsizeFree(dd);
}
return result;
}
/**
* \test this is a test for a invalid dsize value ""
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse14 (void) {
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse("");
if (dd) {
DetectDsizeFree(dd);
return 0;
}
return 1;
}
/**
* \test this is a test for a invalid dsize value " "
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse15 (void) {
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse(" ");
if (dd) {
DetectDsizeFree(dd);
return 0;
}
return 1;
}
/**
* \test this is a test for a invalid dsize value 2<>1
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse16 (void) {
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse("2<>1");
if (dd) {
DetectDsizeFree(dd);
return 0;
}
return 1;
}
/**
* \test this is a test for a valid dsize value 1 <> 2
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse17 (void) {
int result = 0;
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse(" 1 <> 2 ");
if (dd) {
if (dd->dsize == 1 && dd->dsize2 == 2 && dd->mode == DETECTDSIZE_RA)
result = 1;
DetectDsizeFree(dd);
}
return result;
}
/**
* \test this is test for a valid dsize value > 2
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse18 (void) {
int result = 0;
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse("> 2 ");
if (dd) {
if (dd->dsize == 2 && dd->mode == DETECTDSIZE_GT)
result = 1;
DetectDsizeFree(dd);
}
return result;
}
/**
* \test test for a valid dsize value < 12
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse19 (void) {
int result = 0;
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse("< 12 ");
if (dd) {
if (dd->dsize == 12 && dd->mode == DETECTDSIZE_LT)
result = 1;
DetectDsizeFree(dd);
}
return result;
}
/**
* \test test for a valid dsize value 12
*
* \retval 1 on succces
* \retval 0 on failure
*/
int DsizeTestParse20 (void) {
int result = 0;
DetectDsizeData *dd = NULL;
dd = DetectDsizeParse(" 12 ");
if (dd) {
if (dd->dsize == 12 && dd->mode == DETECTDSIZE_EQ)
result = 1;
DetectDsizeFree(dd);
}
return result;
}
/**
* \test DetectDsizeIcmpv6Test01 is a test for checking the working of
* dsize keyword by creating 2 rules and matching a crafted packet
* against them. Only the first one shall trigger.
*/
int DetectDsizeIcmpv6Test01 (void) {
int result = 0;
static uint8_t raw_icmpv6[] = {
0x60, 0x00, 0x00, 0x00, 0x00, 0x30, 0x3a, 0xff,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
0x01, 0x00, 0x7b, 0x85, 0x00, 0x00, 0x00, 0x00,
0x60, 0x4b, 0xe8, 0xbd, 0x00, 0x00, 0x3b, 0xff,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 };
Packet *p = SCMalloc(SIZE_OF_PACKET);
if (p == NULL)
return 0;
IPV6Hdr ip6h;
ThreadVars tv;
DecodeThreadVars dtv;
Signature *s = NULL;
ThreadVars th_v;
DetectEngineThreadCtx *det_ctx = NULL;
memset(&tv, 0, sizeof(ThreadVars));
memset(p, 0, SIZE_OF_PACKET);
p->pkt = (uint8_t *)(p + 1);
memset(&dtv, 0, sizeof(DecodeThreadVars));
memset(&ip6h, 0, sizeof(IPV6Hdr));
memset(&th_v, 0, sizeof(ThreadVars));
FlowInitConfig(FLOW_QUIET);
p->src.family = AF_INET6;
p->dst.family = AF_INET6;
p->ip6h = &ip6h;
DecodeIPV6(&tv, &dtv, p, raw_icmpv6, sizeof(raw_icmpv6), NULL);
DetectEngineCtx *de_ctx = DetectEngineCtxInit();
if (de_ctx == NULL) {
goto end;
}
de_ctx->flags |= DE_QUIET;
s = de_ctx->sig_list = SigInit(de_ctx, "alert icmp any any -> any any "
"(msg:\"ICMP Large ICMP Packet\"; dsize:>8; sid:1; rev:4;)");
if (s == NULL) {
goto end;
}
s = s->next = SigInit(de_ctx, "alert icmp any any -> any any "
"(msg:\"ICMP Large ICMP Packet\"; dsize:>800; sid:2; rev:4;)");
if (s == NULL) {
goto end;
}
SigGroupBuild(de_ctx);
DetectEngineThreadCtxInit(&th_v, (void *)de_ctx, (void *)&det_ctx);
SigMatchSignatures(&th_v, de_ctx, det_ctx, p);
if (PacketAlertCheck(p, 1) == 0) {
printf("sid 1 did not alert, but should have: ");
goto cleanup;
} else if (PacketAlertCheck(p, 2)) {
printf("sid 2 alerted, but should not have: ");
goto cleanup;
}
result = 1;
cleanup:
SigGroupCleanup(de_ctx);
SigCleanSignatures(de_ctx);
DetectEngineThreadCtxDeinit(&th_v, (void *)det_ctx);
DetectEngineCtxFree(de_ctx);
FlowShutdown();
end:
SCFree(p);
return result;
}
#endif /* UNITTESTS */
/**
* \brief this function registers unit tests for dsize
*/
void DsizeRegisterTests(void) {
#ifdef UNITTESTS
UtRegisterTest("DsizeTestParse01", DsizeTestParse01, 1);
UtRegisterTest("DsizeTestParse02", DsizeTestParse02, 1);
UtRegisterTest("DsizeTestParse03", DsizeTestParse03, 1);
UtRegisterTest("DsizeTestParse04", DsizeTestParse04, 1);
UtRegisterTest("DsizeTestParse05", DsizeTestParse05, 1);
UtRegisterTest("DsizeTestParse06", DsizeTestParse06, 1);
UtRegisterTest("DsizeTestParse07", DsizeTestParse07, 1);
UtRegisterTest("DsizeTestParse08", DsizeTestParse08, 1);
UtRegisterTest("DsizeTestParse09", DsizeTestParse09, 1);
UtRegisterTest("DsizeTestParse10", DsizeTestParse10, 1);
UtRegisterTest("DsizeTestParse11", DsizeTestParse11, 1);
UtRegisterTest("DsizeTestParse12", DsizeTestParse12, 1);
UtRegisterTest("DsizeTestParse13", DsizeTestParse13, 1);
UtRegisterTest("DsizeTestParse14", DsizeTestParse14, 1);
UtRegisterTest("DsizeTestParse15", DsizeTestParse15, 1);
UtRegisterTest("DsizeTestParse16", DsizeTestParse16, 1);
UtRegisterTest("DsizeTestParse17", DsizeTestParse17, 1);
UtRegisterTest("DsizeTestParse18", DsizeTestParse18, 1);
UtRegisterTest("DsizeTestParse19", DsizeTestParse19, 1);
UtRegisterTest("DsizeTestParse20", DsizeTestParse20, 1);
UtRegisterTest("DetectDsizeIcmpv6Test01", DetectDsizeIcmpv6Test01, 1);
#endif /* UNITTESTS */
}