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107 lines
3.2 KiB
C
107 lines
3.2 KiB
C
/* Copyright (C) 2007-2010 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 Victor Julien <victor@inliniac.net>
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*
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* Implements the nocase keyword
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*/
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#include "suricata-common.h"
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#include "decode.h"
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#include "detect.h"
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#include "detect-parse.h"
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#include "detect-content.h"
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#include "detect-nocase.h"
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#include "util-debug.h"
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static int DetectNocaseSetup (DetectEngineCtx *, Signature *, const char *);
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void DetectNocaseRegister(void)
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{
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sigmatch_table[DETECT_NOCASE].name = "nocase";
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sigmatch_table[DETECT_NOCASE].desc = "modify content match to be case insensitive";
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sigmatch_table[DETECT_NOCASE].url = DOC_URL DOC_VERSION "/rules/payload-keywords.html#nocase";
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sigmatch_table[DETECT_NOCASE].Match = NULL;
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sigmatch_table[DETECT_NOCASE].Setup = DetectNocaseSetup;
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sigmatch_table[DETECT_NOCASE].Free = NULL;
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sigmatch_table[DETECT_NOCASE].RegisterTests = NULL;
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sigmatch_table[DETECT_NOCASE].flags |= SIGMATCH_NOOPT;
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}
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/**
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* \internal
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* \brief Apply the nocase keyword to the last pattern match, either content or uricontent
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* \param det_ctx detection engine ctx
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* \param s signature
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* \param nullstr should be null
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* \retval 0 ok
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* \retval -1 failure
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*/
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static int DetectNocaseSetup (DetectEngineCtx *de_ctx, Signature *s, const char *nullstr)
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{
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SCEnter();
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SigMatch *pm = NULL;
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int ret = -1;
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if (nullstr != NULL) {
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SCLogError(SC_ERR_INVALID_VALUE, "nocase has value");
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goto end;
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}
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/* retrive the sm to apply the nocase against */
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pm = DetectGetLastSMFromLists(s, DETECT_CONTENT, -1);
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if (pm == NULL) {
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SCLogError(SC_ERR_NOCASE_MISSING_PATTERN, "nocase needs "
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"preceding content option");
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goto end;
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}
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/* verify other conditions. */
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DetectContentData *cd = (DetectContentData *)pm->ctx;;
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if (cd->flags & DETECT_CONTENT_NOCASE) {
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SCLogError(SC_ERR_INVALID_SIGNATURE, "can't use multiple nocase modifiers with the same content");
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goto end;
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}
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/* for consistency in later use (e.g. by MPM construction and hashing),
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* coerce the content string to lower-case. */
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for (uint8_t *c = cd->content; c < cd->content + cd->content_len; c++) {
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*c = u8_tolower(*c);
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}
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cd->flags |= DETECT_CONTENT_NOCASE;
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/* Recreate the context with nocase chars */
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SpmDestroyCtx(cd->spm_ctx);
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cd->spm_ctx = SpmInitCtx(cd->content, cd->content_len, 1,
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de_ctx->spm_global_thread_ctx);
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if (cd->spm_ctx == NULL) {
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goto end;
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}
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ret = 0;
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end:
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SCReturnInt(ret);
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}
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