diff --git a/doc/userguide/rules/transforms.rst b/doc/userguide/rules/transforms.rst index 91ab2ef5fc9e..dd437d77ec81 100644 --- a/doc/userguide/rules/transforms.rst +++ b/doc/userguide/rules/transforms.rst @@ -134,3 +134,23 @@ Example:: alert http any any -> any any (msg:"HTTP with xor"; http.uri; \ xor:"0d0ac8ff"; content:"password="; sid:1;) + +to_lowercase +------------ + +Converts the buffer to lowercase. + +Example:: + + alert http any any -> any any (http.uri; to_lowercase; \ + content:"|this text has been converted to lowercase|"; sid:1;) + +to_uppercase +------------ + +Converts the buffer to uppercase. + +Example:: + + alert http any any -> any any (http.uri; to_uppercase; \ + content:"|THIS TEXT HAS BEEN CONVERTED TO UPPERCASE|"; sid:1;) diff --git a/src/Makefile.am b/src/Makefile.am index 48a5ce850ce2..6ea69ffe4891 100755 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -337,6 +337,7 @@ 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 \ @@ -946,6 +947,7 @@ 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-engine-register.c b/src/detect-engine-register.c index df6e4a738ffc..9c006ca51a6b 100644 --- a/src/detect-engine-register.c +++ b/src/detect-engine-register.c @@ -244,6 +244,7 @@ #include "detect-transform-pcrexform.h" #include "detect-transform-urldecode.h" #include "detect-transform-xor.h" +#include "detect-transform-casechange.h" #include "util-rule-vars.h" @@ -696,6 +697,8 @@ void SigTableSetup(void) DetectTransformPcrexformRegister(); DetectTransformUrlDecodeRegister(); DetectTransformXorRegister(); + DetectTransformToLowerRegister(); + DetectTransformToUpperRegister(); DetectFileHandlerRegister(); diff --git a/src/detect-engine-register.h b/src/detect-engine-register.h index 7d6c457ef9b0..14f9a846cf0a 100644 --- a/src/detect-engine-register.h +++ b/src/detect-engine-register.h @@ -321,6 +321,8 @@ enum DetectKeywordId { DETECT_TRANSFORM_PCREXFORM, DETECT_TRANSFORM_URL_DECODE, DETECT_TRANSFORM_XOR, + DETECT_TRANSFORM_TOLOWER, + DETECT_TRANSFORM_TOUPPER, DETECT_AL_IKE_EXCH_TYPE, DETECT_AL_IKE_SPI_INITIATOR, diff --git a/src/detect-transform-casechange.c b/src/detect-transform-casechange.c new file mode 100644 index 000000000000..7a7735f34264 --- /dev/null +++ b/src/detect-transform-casechange.c @@ -0,0 +1,118 @@ +/* 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 Apply the to_lowercase keyword to the last pattern match + * \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); +} + +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 Apply the to_uppercase keyword to the last pattern match + * \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); +} + +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); +} + +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].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].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 000000000000..db6275b915f7 --- /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 */