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/* Copyright (C) 2023 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 Jeff Lucovsky <jlucovsky@oisf.net>
*
* Implements case changing transforms
*/
#include "suricata-common.h"
#include "detect.h"
#include "detect-engine.h"
#include "detect-parse.h"
#include "detect-transform-casechange.h"
/**
* \internal
* \brief Register the to_lowercase transform
* \param det_ctx detection engine ctx
* \param s signature
* \param optstr options string
* \retval 0 ok
* \retval -1 failure
*/
static int DetectTransformToLowerSetup(DetectEngineCtx *de_ctx, Signature *s, const char *optstr)
{
SCEnter();
int r = DetectSignatureAddTransform(s, DETECT_TRANSFORM_TOLOWER, NULL);
SCReturnInt(r);
}
/**
* \internal
* \brief Apply the to_lowercase keyword to the last pattern match
* \param buffer Inspection buffer
* \param optstr options string
*/
static void DetectTransformToLower(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];
for (uint32_t i = 0; i < input_len; i++) {
output[i] = u8_tolower(input[i]);
}
InspectionBufferCopy(buffer, output, input_len);
}
/**
* \internal
* \brief Register the to_upperrcase transform
* \param det_ctx detection engine ctx
* \param s signature
* \param optstr options string
* \retval 0 ok
* \retval -1 failure
*/
static int DetectTransformToUpperSetup(DetectEngineCtx *de_ctx, Signature *s, const char *optstr)
{
SCEnter();
int r = DetectSignatureAddTransform(s, DETECT_TRANSFORM_TOUPPER, NULL);
SCReturnInt(r);
}
/**
* \internal
* \brief Apply the to_uppercase keyword to the last pattern match
* \param buffer Inspection buffer
* \param optstr options string
*/
static void DetectTransformToUpper(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];
for (uint32_t i = 0; i < input_len; i++) {
output[i] = u8_toupper(input[i]);
}
InspectionBufferCopy(buffer, output, input_len);
}
/*
* \internal
* \brief Check if content is compatible with transform
*
* If the content contains any lowercase characters, than it is not compatible.
*/
static bool TransformToUpperValidate(const uint8_t *content, uint16_t content_len, void *options)
{
if (content) {
for (uint32_t i = 0; i < content_len; i++) {
if (islower(*content++)) {
return false;
}
}
}
return true;
}
/*
* \internal
* \brief Check if content is compatible with transform
*
* If the content contains any uppercase characters, than it is not compatible.
*/
static bool TransformToLowerValidate(const uint8_t *content, uint16_t content_len, void *options)
{
if (content) {
for (uint32_t i = 0; i < content_len; i++) {
if (isupper(*content++)) {
return false;
}
}
}
return true;
}
void DetectTransformToUpperRegister(void)
{
sigmatch_table[DETECT_TRANSFORM_TOUPPER].name = "to_uppercase";
sigmatch_table[DETECT_TRANSFORM_TOUPPER].desc = "convert buffer to uppercase";
sigmatch_table[DETECT_TRANSFORM_TOUPPER].url = "/rules/transforms.html#to_uppercase";
sigmatch_table[DETECT_TRANSFORM_TOUPPER].Transform = DetectTransformToUpper;
sigmatch_table[DETECT_TRANSFORM_TOUPPER].TransformValidate = TransformToUpperValidate;
sigmatch_table[DETECT_TRANSFORM_TOUPPER].Setup = DetectTransformToUpperSetup;
sigmatch_table[DETECT_TRANSFORM_TOUPPER].flags |= SIGMATCH_NOOPT;
}
void DetectTransformToLowerRegister(void)
{
sigmatch_table[DETECT_TRANSFORM_TOLOWER].name = "to_lowercase";
sigmatch_table[DETECT_TRANSFORM_TOLOWER].desc = "convert buffer to lowercase";
sigmatch_table[DETECT_TRANSFORM_TOLOWER].url = "/rules/transforms.html#to_lowercase";
sigmatch_table[DETECT_TRANSFORM_TOLOWER].Transform = DetectTransformToLower;
sigmatch_table[DETECT_TRANSFORM_TOLOWER].TransformValidate = TransformToLowerValidate;
sigmatch_table[DETECT_TRANSFORM_TOLOWER].Setup = DetectTransformToLowerSetup;
sigmatch_table[DETECT_TRANSFORM_TOLOWER].flags |= SIGMATCH_NOOPT;
}
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