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detect: use generic integer functions for tcp mss

Browse Source 
Ticket: #4112
pull/7467/head
Philippe Antoine 3 years ago committed by Victor Julien
parent 025b510cac
commit bfdf5b1952
4 changed files with 17 additions and 386 deletions
Show Stats Download Patch File Download Diff File

1
src/Makefile.am
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@ -1208,7 +1208,6 @@ EXTRA_DIST = \
tests/detect-icmpv6hdr.c \
tests/detect-snmp-pdu_type.c \
tests/detect-snmp-version.c \
tests/detect-tcpmss.c \
tests/detect-template.c \
tests/detect-transform-pcrexform.c \
tests/detect-transform-xor.c \

238
src/detect-tcpmss.c
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@ -27,16 +27,11 @@
#include "detect.h"
#include "detect-parse.h"
#include "detect-engine-prefilter-common.h"
#include "detect-engine-uint.h"
#include "util-byte.h"
#include "detect-tcpmss.h"
/**
* \brief Regex for parsing our options
*/
#define PARSE_REGEX "^\\s*([0-9]*)?\\s*([<>=-]+)?\\s*([0-9]+)?\\s*$"
static DetectParseRegex parse_regex;
/* prototypes */
static int DetectTcpmssMatch (DetectEngineThreadCtx *, Packet *,
@ -61,37 +56,19 @@ void DetectTcpmssRegister(void)
sigmatch_table[DETECT_TCPMSS].Match = DetectTcpmssMatch;
sigmatch_table[DETECT_TCPMSS].Setup = DetectTcpmssSetup;
sigmatch_table[DETECT_TCPMSS].Free = DetectTcpmssFree;
#ifdef UNITTESTS
sigmatch_table[DETECT_TCPMSS].RegisterTests = DetectTcpmssRegisterTests;
#endif
sigmatch_table[DETECT_TCPMSS].SupportsPrefilter = PrefilterTcpmssIsPrefilterable;
sigmatch_table[DETECT_TCPMSS].SetupPrefilter = PrefilterSetupTcpmss;
DetectSetupParseRegexes(PARSE_REGEX, &parse_regex);
return;
}
static inline int TcpmssMatch(const uint16_t parg, const uint8_t mode,
const uint16_t darg1, const uint16_t darg2)
{
if (mode == DETECT_TCPMSS_EQ && parg == darg1)
return 1;
else if (mode == DETECT_TCPMSS_LT && parg < darg1)
return 1;
else if (mode == DETECT_TCPMSS_GT && parg > darg1)
return 1;
else if (mode == DETECT_TCPMSS_RA && (parg > darg1 && parg < darg2))
return 1;
return 0;
}
/**
* \brief This function is used to match TCPMSS rule option on a packet with those passed via tcpmss:
* \brief This function is used to match TCPMSS rule option on a packet with those passed via
* tcpmss:
*
* \param det_ctx pointer to the pattern matcher thread
* \param p pointer to the current packet
* \param ctx pointer to the sigmatch that we will cast into DetectTcpmssData
* \param ctx pointer to the sigmatch that we will cast into DetectU16Data
*
* \retval 0 no match
* \retval 1 match
@ -108,165 +85,8 @@ static int DetectTcpmssMatch (DetectEngineThreadCtx *det_ctx, Packet *p,
uint16_t ptcpmss = TCP_GET_MSS(p);
const DetectTcpmssData *tcpmssd = (const DetectTcpmssData *)ctx;
return TcpmssMatch(ptcpmss, tcpmssd->mode, tcpmssd->arg1, tcpmssd->arg2);
}
/**
* \brief This function is used to parse tcpmss options passed via tcpmss: keyword
*
* \param tcpmssstr Pointer to the user provided tcpmss options
*
* \retval tcpmssd pointer to DetectTcpmssData on success
* \retval NULL on failure
*/
static DetectTcpmssData *DetectTcpmssParse (const char *tcpmssstr)
{
DetectTcpmssData *tcpmssd = NULL;
char *arg1 = NULL;
char *arg2 = NULL;
char *arg3 = NULL;
int ret = 0, res = 0;
size_t pcre2_len;
ret = DetectParsePcreExec(&parse_regex, tcpmssstr, 0, 0);
if (ret < 2 || ret > 4) {
SCLogError(SC_ERR_PCRE_MATCH, "parse error, ret %" PRId32 "", ret);
goto error;
}
const char *str_ptr;
res = pcre2_substring_get_bynumber(parse_regex.match, 1, (PCRE2_UCHAR8 **)&str_ptr, &pcre2_len);
if (res < 0) {
SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre2_substring_get_bynumber failed");
goto error;
}
arg1 = (char *) str_ptr;
SCLogDebug("Arg1 \"%s\"", arg1);
if (ret >= 3) {
res = pcre2_substring_get_bynumber(
parse_regex.match, 2, (PCRE2_UCHAR8 **)&str_ptr, &pcre2_len);
if (res < 0) {
SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre2_substring_get_bynumber failed");
goto error;
}
arg2 = (char *) str_ptr;
SCLogDebug("Arg2 \"%s\"", arg2);
if (ret >= 4) {
res = pcre2_substring_get_bynumber(
parse_regex.match, 3, (PCRE2_UCHAR8 **)&str_ptr, &pcre2_len);
if (res < 0) {
SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre2_substring_get_bynumber failed");
goto error;
}
arg3 = (char *) str_ptr;
SCLogDebug("Arg3 \"%s\"", arg3);
}
}
tcpmssd = SCMalloc(sizeof (DetectTcpmssData));
if (unlikely(tcpmssd == NULL))
goto error;
tcpmssd->arg1 = 0;
tcpmssd->arg2 = 0;
if (arg2 != NULL) {
/*set the values*/
switch(arg2[0]) {
case '<':
if (arg3 == NULL)
goto error;
tcpmssd->mode = DETECT_TCPMSS_LT;
if (StringParseUint16(&tcpmssd->arg1, 10, 0, (const char *)arg3) < 0) {
SCLogError(SC_ERR_INVALID_SIGNATURE, "Invalid first arg: %s", arg3);
goto error;
}
SCLogDebug("tcpmss is %"PRIu16"",tcpmssd->arg1);
if (strlen(arg1) > 0)
goto error;
break;
case '>':
if (arg3 == NULL)
goto error;
tcpmssd->mode = DETECT_TCPMSS_GT;
if (StringParseUint16(&tcpmssd->arg1, 10, 0, (const char *)arg3) < 0) {
SCLogError(SC_ERR_INVALID_SIGNATURE, "Invalid first arg: %s", arg3);
goto error;
}
SCLogDebug("tcpmss is %"PRIu16"",tcpmssd->arg1);
if (strlen(arg1) > 0)
goto error;
break;
case '-':
if (arg1 == NULL || strlen(arg1)== 0)
goto error;
if (arg3 == NULL || strlen(arg3)== 0)
goto error;
tcpmssd->mode = DETECT_TCPMSS_RA;
if (StringParseUint16(&tcpmssd->arg1, 10, 0, (const char *)arg1) < 0) {
SCLogError(SC_ERR_INVALID_SIGNATURE, "Invalid first arg: %s", arg1);
goto error;
}
if (StringParseUint16(&tcpmssd->arg2, 10, 0, (const char *)arg3) < 0) {
SCLogError(SC_ERR_INVALID_SIGNATURE, "Invalid second arg: %s", arg3);
goto error;
}
SCLogDebug("tcpmss is %"PRIu16" to %"PRIu16"",tcpmssd->arg1, tcpmssd->arg2);
if (tcpmssd->arg1 >= tcpmssd->arg2) {
SCLogError(SC_ERR_INVALID_SIGNATURE, "Invalid tcpmss range. ");
goto error;
}
break;
default:
tcpmssd->mode = DETECT_TCPMSS_EQ;
if ((arg2 != NULL && strlen(arg2) > 0) ||
(arg3 != NULL && strlen(arg3) > 0) ||
(arg1 == NULL ||strlen(arg1) == 0))
goto error;
if (StringParseUint16(&tcpmssd->arg1, 10, 0, (const char *)arg1) < 0) {
SCLogError(SC_ERR_INVALID_SIGNATURE, "Invalid first arg: %s", arg1);
goto error;
}
break;
}
} else {
tcpmssd->mode = DETECT_TCPMSS_EQ;
if ((arg3 != NULL && strlen(arg3) > 0) ||
(arg1 == NULL ||strlen(arg1) == 0))
goto error;
if (StringParseUint16(&tcpmssd->arg1, 10, 0, (const char *)arg1) < 0) {
SCLogError(SC_ERR_INVALID_SIGNATURE, "Invalid first arg: %s", arg1);
goto error;
}
}
pcre2_substring_free((PCRE2_UCHAR8 *)arg1);
pcre2_substring_free((PCRE2_UCHAR8 *)arg2);
pcre2_substring_free((PCRE2_UCHAR8 *)arg3);
return tcpmssd;
error:
if (tcpmssd)
SCFree(tcpmssd);
if (arg1)
pcre2_substring_free((PCRE2_UCHAR8 *)arg1);
if (arg2)
pcre2_substring_free((PCRE2_UCHAR8 *)arg2);
if (arg3)
pcre2_substring_free((PCRE2_UCHAR8 *)arg3);
return NULL;
const DetectU16Data *tcpmssd = (const DetectU16Data *)ctx;
return DetectU16Match(ptcpmss, tcpmssd);
}
/**
@ -281,7 +101,7 @@ error:
*/
static int DetectTcpmssSetup (DetectEngineCtx *de_ctx, Signature *s, const char *tcpmssstr)
{
DetectTcpmssData *tcpmssd = DetectTcpmssParse(tcpmssstr);
DetectU16Data *tcpmssd = DetectU16Parse(tcpmssstr);
if (tcpmssd == NULL)
return -1;
@ -301,14 +121,13 @@ static int DetectTcpmssSetup (DetectEngineCtx *de_ctx, Signature *s, const char
}
/**
* \brief this function will free memory associated with DetectTcpmssData
* \brief this function will free memory associated with DetectU16Data
*
* \param ptr pointer to DetectTcpmssData
* \param ptr pointer to DetectU16Data
*/
void DetectTcpmssFree(DetectEngineCtx *de_ctx, void *ptr)
{
DetectTcpmssData *tcpmssd = (DetectTcpmssData *)ptr;
SCFree(tcpmssd);
rs_detect_u16_free(ptr);
}
/* prefilter code */
@ -330,41 +149,22 @@ PrefilterPacketTcpmssMatch(DetectEngineThreadCtx *det_ctx, Packet *p, const void
if (!PrefilterPacketHeaderExtraMatch(ctx, p))
return;
DetectU16Data du16;
du16.mode = ctx->v1.u8[0];
du16.arg1 = ctx->v1.u16[1];
du16.arg2 = ctx->v1.u16[2];
/* if we match, add all the sigs that use this prefilter. This means
* that these will be inspected further */
if (TcpmssMatch(ptcpmss, ctx->v1.u8[0], ctx->v1.u16[1], ctx->v1.u16[2]))
{
if (DetectU16Match(ptcpmss, &du16)) {
SCLogDebug("packet matches tcpmss/hl %u", ptcpmss);
PrefilterAddSids(&det_ctx->pmq, ctx->sigs_array, ctx->sigs_cnt);
}
}
static void
PrefilterPacketTcpmssSet(PrefilterPacketHeaderValue *v, void *smctx)
{
const DetectTcpmssData *a = smctx;
v->u8[0] = a->mode;
v->u16[1] = a->arg1;
v->u16[2] = a->arg2;
}
static bool
PrefilterPacketTcpmssCompare(PrefilterPacketHeaderValue v, void *smctx)
{
const DetectTcpmssData *a = smctx;
if (v.u8[0] == a->mode &&
v.u16[1] == a->arg1 &&
v.u16[2] == a->arg2)
return true;
return false;
}
static int PrefilterSetupTcpmss(DetectEngineCtx *de_ctx, SigGroupHead *sgh)
{
return PrefilterSetupPacketHeader(de_ctx, sgh, DETECT_TCPMSS,
PrefilterPacketTcpmssSet,
PrefilterPacketTcpmssCompare,
PrefilterPacketTcpmssMatch);
return PrefilterSetupPacketHeader(de_ctx, sgh, DETECT_TCPMSS, PrefilterPacketU16Set,
PrefilterPacketU16Compare, PrefilterPacketTcpmssMatch);
}
static bool PrefilterTcpmssIsPrefilterable(const Signature *s)
@ -378,7 +178,3 @@ static bool PrefilterTcpmssIsPrefilterable(const Signature *s)
}
return false;
}
#ifdef UNITTESTS
#include "tests/detect-tcpmss.c"
#endif

12
src/detect-tcpmss.h
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@ -24,18 +24,6 @@
#ifndef _DETECT_TCPMSS_H
#define _DETECT_TCPMSS_H
#define DETECT_TCPMSS_LT 0 /**< "less than" operator */
#define DETECT_TCPMSS_EQ 1 /**< "equals" operator (default) */
#define DETECT_TCPMSS_GT 2 /**< "greater than" operator */
#define DETECT_TCPMSS_RA 3 /**< "range" operator */
typedef struct DetectTcpmssData_ {
uint16_t arg1; /**< first arg value in the signature*/
uint16_t arg2; /**< second arg value in the signature, in case of range
operator*/
uint8_t mode; /**< operator used in the signature */
} DetectTcpmssData;
void DetectTcpmssRegister(void);
#endif /* _DETECT_TCPMSS_H */

152
src/tests/detect-tcpmss.c
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@ -1,152 +0,0 @@
/* Copyright (C) 2007-2019 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.
*/
#include "../suricata-common.h"
#include "../detect.h"
#include "../detect-parse.h"
#include "../detect-engine-prefilter-common.h"
#include "../detect-tcpmss.h"
#include "../util-unittest.h"
/**
* \test setting up a valid tcpmss value.
*/
static int DetectTcpmssParseTest01 (void)
{
DetectTcpmssData *tcpmssd = DetectTcpmssParse("10");
FAIL_IF_NULL(tcpmssd);
FAIL_IF_NOT(tcpmssd->arg1 == 10);
FAIL_IF_NOT(tcpmssd->mode == DETECT_TCPMSS_EQ);
DetectTcpmssFree(NULL, tcpmssd);
PASS;
}
/**
* \test setting up a valid tcpmss value with "<" operator.
*/
static int DetectTcpmssParseTest02 (void)
{
DetectTcpmssData *tcpmssd = DetectTcpmssParse("<10");
FAIL_IF_NULL(tcpmssd);
FAIL_IF_NOT(tcpmssd->arg1 == 10);
FAIL_IF_NOT(tcpmssd->mode == DETECT_TCPMSS_LT);
DetectTcpmssFree(NULL, tcpmssd);
PASS;
}
/**
* \test setting up an valid tcpmss values with "-" operator.
*/
static int DetectTcpmssParseTest03 (void)
{
DetectTcpmssData *tcpmssd = DetectTcpmssParse("1-2");
FAIL_IF_NULL(tcpmssd);
FAIL_IF_NOT(tcpmssd->arg1 == 1);
FAIL_IF_NOT(tcpmssd->mode == DETECT_TCPMSS_RA);
DetectTcpmssFree(NULL, tcpmssd);
PASS;
}
/**
* \test setting up an valid tcpmss value with
* ">" operator and include spaces arround the given values.
*/
static int DetectTcpmssParseTest04 (void)
{
DetectTcpmssData *tcpmssd = DetectTcpmssParse(" > 10 ");
FAIL_IF_NULL(tcpmssd);
FAIL_IF_NOT(tcpmssd->arg1 == 10);
FAIL_IF_NOT(tcpmssd->mode == DETECT_TCPMSS_GT);
DetectTcpmssFree(NULL, tcpmssd);
PASS;
}
/**
* \test setting up an valid tcpmss values with
* "-" operator and include spaces arround the given values.
*/
static int DetectTcpmssParseTest05 (void)
{
DetectTcpmssData *tcpmssd = DetectTcpmssParse(" 1 - 2 ");
FAIL_IF_NULL(tcpmssd);
FAIL_IF_NOT(tcpmssd->arg1 == 1);
FAIL_IF_NOT(tcpmssd->arg2 == 2);
FAIL_IF_NOT(tcpmssd->mode == DETECT_TCPMSS_RA);
DetectTcpmssFree(NULL, tcpmssd);
PASS;
}
/**
* \test setting up an valid tcpmss values with
* invalid "=" operator and include spaces arround the given values.
*/
static int DetectTcpmssParseTest06 (void)
{
DetectTcpmssData *tcpmssd = DetectTcpmssParse(" 1 = 2 ");
FAIL_IF_NOT_NULL(tcpmssd);
PASS;
}
/**
* \test setting up valid tcpmss values with
* invalid "<>" operator and include spaces arround the given values.
*/
static int DetectTcpmssParseTest07 (void)
{
DetectTcpmssData *tcpmssd = DetectTcpmssParse(" 1<>2 ");
FAIL_IF_NOT_NULL(tcpmssd);
PASS;
}
/**
* \brief this function registers unit tests for DetectTcpmss
*/
void DetectTcpmssRegisterTests(void)
{
UtRegisterTest("DetectTcpmssParseTest01", DetectTcpmssParseTest01);
UtRegisterTest("DetectTcpmssParseTest02", DetectTcpmssParseTest02);
UtRegisterTest("DetectTcpmssParseTest03", DetectTcpmssParseTest03);
UtRegisterTest("DetectTcpmssParseTest04", DetectTcpmssParseTest04);
UtRegisterTest("DetectTcpmssParseTest05", DetectTcpmssParseTest05);
UtRegisterTest("DetectTcpmssParseTest06", DetectTcpmssParseTest06);
UtRegisterTest("DetectTcpmssParseTest07", DetectTcpmssParseTest07);
}
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