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/* Copyright (C) 2007-2020 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 nocase keyword
*/
#include "suricata-common.h"
#include "detect.h"
#include "detect-engine.h"
#include "detect-engine-prefilter.h"
#include "detect-engine-build.h"
#include "detect-parse.h"
#include "detect-transform-strip-whitespace.h"
#include "util-unittest.h"
#include "util-print.h"
static int DetectTransformStripWhitespaceSetup (DetectEngineCtx *, Signature *, const char *);
#ifdef UNITTESTS
static void DetectTransformStripWhitespaceRegisterTests(void);
#endif
static void TransformStripWhitespace(InspectionBuffer *buffer, void *options);
static bool TransformStripWhitespaceValidate(const uint8_t *content, uint16_t content_len, void *options);
void DetectTransformStripWhitespaceRegister(void)
{
sigmatch_table[DETECT_TRANSFORM_STRIP_WHITESPACE].name = "strip_whitespace";
sigmatch_table[DETECT_TRANSFORM_STRIP_WHITESPACE].desc =
"modify buffer to strip whitespace before inspection";
sigmatch_table[DETECT_TRANSFORM_STRIP_WHITESPACE].url =
"/rules/transforms.html#strip-whitespace";
sigmatch_table[DETECT_TRANSFORM_STRIP_WHITESPACE].Transform =
TransformStripWhitespace;
sigmatch_table[DETECT_TRANSFORM_STRIP_WHITESPACE].TransformValidate =
TransformStripWhitespaceValidate;
sigmatch_table[DETECT_TRANSFORM_STRIP_WHITESPACE].Setup =
DetectTransformStripWhitespaceSetup;
#ifdef UNITTESTS
sigmatch_table[DETECT_TRANSFORM_STRIP_WHITESPACE].RegisterTests =
DetectTransformStripWhitespaceRegisterTests;
#endif
sigmatch_table[DETECT_TRANSFORM_STRIP_WHITESPACE].flags |= SIGMATCH_NOOPT;
}
/**
* \internal
* \brief Apply the nocase keyword to the last pattern match, either content or uricontent
* \param det_ctx detection engine ctx
* \param s signature
* \param nullstr should be null
* \retval 0 ok
* \retval -1 failure
*/
static int DetectTransformStripWhitespaceSetup (DetectEngineCtx *de_ctx, Signature *s, const char *nullstr)
{
SCEnter();
int r = DetectSignatureAddTransform(s, DETECT_TRANSFORM_STRIP_WHITESPACE, NULL);
SCReturnInt(r);
}
/*
* \brief Validate content bytes to see if it's compatible with this transform
* \param content Byte array to check for compatibility
* \param content_len Number of bytes to check
* \param options Ignored
* \retval false If the string contains spaces
* \retval true Otherwise.
*/
static bool TransformStripWhitespaceValidate(const uint8_t *content,
uint16_t content_len, void *options)
{
if (content) {
for (uint32_t i = 0; i < content_len; i++) {
if (isspace(*content++)) {
return false;
}
}
}
return true;
}
static void TransformStripWhitespace(InspectionBuffer *buffer, void *options)
{
const uint8_t *input = buffer->inspect;
const uint32_t input_len = buffer->inspect_len;
if (input_len == 0) {
return;
}
uint8_t output[input_len]; // we can only shrink
uint8_t *oi = output, *os = output;
//PrintRawDataFp(stdout, input, input_len);
for (uint32_t i = 0; i < input_len; i++) {
if (!isspace(*input)) {
*oi++ = *input;
}
input++;
}
uint32_t output_size = oi - os;
//PrintRawDataFp(stdout, output, output_size);
InspectionBufferCopy(buffer, os, output_size);
}
#ifdef UNITTESTS
static int TransformDoubleWhitespace(InspectionBuffer *buffer)
{
const uint8_t *input = buffer->inspect;
const uint32_t input_len = buffer->inspect_len;
uint8_t output[input_len * 2]; // if all chars are whitespace this fits
uint8_t *oi = output, *os = output;
PrintRawDataFp(stdout, input, input_len);
for (uint32_t i = 0; i < input_len; i++) {
if (isspace(*input)) {
*oi++ = *input;
}
*oi++ = *input;
input++;
}
uint32_t output_size = oi - os;
PrintRawDataFp(stdout, output, output_size);
InspectionBufferCopy(buffer, os, output_size);
return 0;
}
static int DetectTransformStripWhitespaceTest01(void)
{
const uint8_t *input = (const uint8_t *)" A B C D ";
uint32_t input_len = strlen((char *)input);
InspectionBuffer buffer;
InspectionBufferInit(&buffer, 8);
InspectionBufferSetup(NULL, -1, &buffer, input, input_len);
PrintRawDataFp(stdout, buffer.inspect, buffer.inspect_len);
TransformStripWhitespace(&buffer, NULL);
PrintRawDataFp(stdout, buffer.inspect, buffer.inspect_len);
InspectionBufferFree(&buffer);
PASS;
}
static int DetectTransformStripWhitespaceTest02(void)
{
const uint8_t *input = (const uint8_t *)" A B C D ";
uint32_t input_len = strlen((char *)input);
InspectionBuffer buffer;
InspectionBufferInit(&buffer, 8);
InspectionBufferSetup(NULL, -1, &buffer, input, input_len);
PrintRawDataFp(stdout, buffer.inspect, buffer.inspect_len);
TransformDoubleWhitespace(&buffer);
PrintRawDataFp(stdout, buffer.inspect, buffer.inspect_len);
TransformDoubleWhitespace(&buffer);
PrintRawDataFp(stdout, buffer.inspect, buffer.inspect_len);
TransformStripWhitespace(&buffer, NULL);
PrintRawDataFp(stdout, buffer.inspect, buffer.inspect_len);
InspectionBufferFree(&buffer);
PASS;
}
static int DetectTransformStripWhitespaceTest03(void)
{
const char rule[] = "alert http any any -> any any (http_request_line; strip_whitespace; content:\"GET/HTTP\"; sid:1;)";
ThreadVars th_v;
DetectEngineThreadCtx *det_ctx = NULL;
memset(&th_v, 0, sizeof(th_v));
DetectEngineCtx *de_ctx = DetectEngineCtxInit();
FAIL_IF_NULL(de_ctx);
Signature *s = DetectEngineAppendSig(de_ctx, rule);
FAIL_IF_NULL(s);
SigGroupBuild(de_ctx);
DetectEngineThreadCtxInit(&th_v, (void *)de_ctx, (void *)&det_ctx);
DetectEngineThreadCtxDeinit(&th_v, (void *)det_ctx);
DetectEngineCtxFree(de_ctx);
PASS;
}
static void DetectTransformStripWhitespaceRegisterTests(void)
{
UtRegisterTest("DetectTransformStripWhitespaceTest01",
DetectTransformStripWhitespaceTest01);
UtRegisterTest("DetectTransformStripWhitespaceTest02",
DetectTransformStripWhitespaceTest02);
UtRegisterTest("DetectTransformStripWhitespaceTest03",
DetectTransformStripWhitespaceTest03);
}
#endif
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