From: Jeff Lucovsky Date: Thu, 9 Nov 2023 10:39:33 +0000 (-0500) Subject: detect/transform: Add case changing transforms X-Git-Tag: suricata-8.0.0-beta1~2083 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e5c2f9a56dee82fc498d85aec68d028b89237544;p=thirdparty%2Fsuricata.git detect/transform: Add case changing transforms This commit adds the implementation for the case changing transforms: to_lowercase and to_uppercase Issue: 6439 --- diff --git a/src/Makefile.am b/src/Makefile.am index 8f6d9ced99..a125e2a432 100755 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -338,6 +338,7 @@ noinst_HEADERS = \ detect-tls-version.h \ detect-tls-random.h \ detect-tos.h \ + detect-transform-casechange.h \ detect-transform-compress-whitespace.h \ detect-transform-dotprefix.h \ detect-transform-md5.h \ @@ -949,6 +950,7 @@ libsuricata_c_a_SOURCES = \ detect-tls-version.c \ detect-tls-random.c \ detect-tos.c \ + detect-transform-casechange.c \ detect-transform-compress-whitespace.c \ detect-transform-dotprefix.c \ detect-transform-md5.c \ diff --git a/src/detect-transform-casechange.c b/src/detect-transform-casechange.c new file mode 100644 index 0000000000..851030828c --- /dev/null +++ b/src/detect-transform-casechange.c @@ -0,0 +1,169 @@ +/* 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 + * + * 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; +} diff --git a/src/detect-transform-casechange.h b/src/detect-transform-casechange.h new file mode 100644 index 0000000000..db6275b915 --- /dev/null +++ b/src/detect-transform-casechange.h @@ -0,0 +1,31 @@ +/* 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 + */ + +#ifndef __DETECT_TRANSFORM_CASECHANGE_H +#define __DETECT_TRANSFORM_CASECHANGE_H + +/* prototypes */ +void DetectTransformToLowerRegister(void); +void DetectTransformToUpperRegister(void); + +#endif /* __DETECT_TRANSFORM_CASECHANGE_H */