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111 lines
3.5 KiB
C
111 lines
3.5 KiB
C
/* Copyright (C) 2020 Open Information Security Foundation
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*
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* You can copy, redistribute or modify this Program under the terms of
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* the GNU General Public License version 2 as published by the Free
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* Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* version 2 along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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/**
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* \file
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*
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* \author Jeff Lucovsky <jeff@lucovsky.org>
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*
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* Implements the pcrexform transform keyword with option support
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*/
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#include "suricata-common.h"
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#include "detect.h"
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#include "detect-engine.h"
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#include "detect-parse.h"
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#include "detect-transform-pcrexform.h"
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typedef DetectParseRegex DetectTransformPcrexformData;
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static int DetectTransformPcrexformSetup (DetectEngineCtx *, Signature *, const char *);
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static void DetectTransformPcrexformFree(DetectEngineCtx *, void *);
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static void DetectTransformPcrexform(InspectionBuffer *buffer, void *options);
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void DetectTransformPcrexformRegister(void)
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{
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sigmatch_table[DETECT_TRANSFORM_PCREXFORM].name = "pcrexform";
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sigmatch_table[DETECT_TRANSFORM_PCREXFORM].desc =
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"modify buffer via PCRE before inspection";
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sigmatch_table[DETECT_TRANSFORM_PCREXFORM].url = "/rules/transforms.html#pcre-xform";
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sigmatch_table[DETECT_TRANSFORM_PCREXFORM].Transform =
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DetectTransformPcrexform;
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sigmatch_table[DETECT_TRANSFORM_PCREXFORM].Free =
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DetectTransformPcrexformFree;
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sigmatch_table[DETECT_TRANSFORM_PCREXFORM].Setup =
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DetectTransformPcrexformSetup;
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sigmatch_table[DETECT_TRANSFORM_PCREXFORM].flags |= SIGMATCH_QUOTES_MANDATORY;
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}
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static void DetectTransformPcrexformFree(DetectEngineCtx *de_ctx, void *ptr)
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{
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if (ptr != NULL) {
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DetectTransformPcrexformData *pxd = (DetectTransformPcrexformData *) ptr;
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SCFree(pxd);
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}
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}
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/**
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* \internal
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* \brief Apply the pcrexform keyword to the last pattern match
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* \param det_ctx detection engine ctx
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* \param s signature
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* \param regexstr options string
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* \retval 0 ok
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* \retval -1 failure
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*/
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static int DetectTransformPcrexformSetup (DetectEngineCtx *de_ctx, Signature *s, const char *regexstr)
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{
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SCEnter();
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// Create pxd from regexstr
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DetectTransformPcrexformData *pxd = SCCalloc(sizeof(*pxd), 1);
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if (pxd == NULL) {
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SCLogDebug("pxd allocation failed");
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SCReturnInt(-1);
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}
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DetectSetupParseRegexes(regexstr, pxd);
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int r = DetectSignatureAddTransform(s, DETECT_TRANSFORM_PCREXFORM, pxd);
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if (r != 0) {
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SCFree(pxd);
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}
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SCReturnInt(r);
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}
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static void DetectTransformPcrexform(InspectionBuffer *buffer, void *options)
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{
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const char *input = (const char *)buffer->inspect;
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const uint32_t input_len = buffer->inspect_len;
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DetectTransformPcrexformData *pxd = options;
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int ov[MAX_SUBSTRINGS];
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int ret = DetectParsePcreExecLen(pxd, input, input_len, 0, 0, ov, MAX_SUBSTRINGS);
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if (ret > 0) {
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const char *str;
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ret = pcre_get_substring((char *) buffer->inspect, ov,
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MAX_SUBSTRINGS, ret - 1, &str);
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if (ret >= 0) {
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InspectionBufferCopy(buffer, (uint8_t *)str, (uint32_t) ret);
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pcre_free_substring(str);
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}
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}
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}
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