detect-rawbytes.c

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/* Copyright (C) 2007-2018 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 Victor Julien <victor@inliniac.net>
 *
 * Implements rawbytes keyword support
 *
 * \todo Provide un-normalized telnet dce/rpc buffers to match on
 */
 
#include "suricata-common.h"
 
#include "decode.h"
#include "detect.h"
#include "detect-parse.h"
#include "detect-rawbytes.h"
#include "detect-engine.h"
 
#include "detect-content.h"
#include "detect-pcre.h"
 
#include "util-debug.h"
 
static int DetectRawbytesSetup(DetectEngineCtx *, Signature *, const char *);
 
void DetectRawbytesRegister(void)
{
    sigmatch_table[DETECT_RAWBYTES].name = "rawbytes";
    sigmatch_table[DETECT_RAWBYTES].desc =
            "dummy keyword to be compatible with snort signatures without effect";
    sigmatch_table[DETECT_RAWBYTES].url = "/rules/payload-keywords.html#rawbytes";
    sigmatch_table[DETECT_RAWBYTES].Setup = DetectRawbytesSetup;
    sigmatch_table[DETECT_RAWBYTES].flags |= SIGMATCH_NOOPT;
}
 
static int DetectRawbytesSetup(DetectEngineCtx *de_ctx, Signature *s, const char *nullstr)
{
    SCEnter();
 
    if (nullstr != NULL) {
        SCLogError("rawbytes has no value");
        SCReturnInt(-1);
    }
 
    if (s->init_data->list != DETECT_SM_LIST_NOTSET) {
        SCLogError("\"rawbytes\" cannot be combined "
                   "with the \"%s\" sticky buffer",
                DetectEngineBufferTypeGetNameById(de_ctx, s->init_data->list));
        SCReturnInt(-1);
    }
 
    SigMatch *pm = DetectGetLastSMByListId(s, DETECT_SM_LIST_PMATCH, DETECT_CONTENT, -1);
    if (pm == NULL) {
        SCLogError("\"rawbytes\" needs a preceding content option");
        SCReturnInt(-1);
    }
 
    switch (pm->type) {
        case DETECT_CONTENT: {
            DetectContentData *cd = (DetectContentData *)pm->ctx;
            if (cd->flags & DETECT_CONTENT_RAWBYTES) {
                SCLogError("can't use multiple rawbytes modifiers for the same content. ");
                SCReturnInt(-1);
            }
            cd->flags |= DETECT_CONTENT_RAWBYTES;
            break;
        }
        default:
            SCLogError("\"rawbytes\" needs a preceding content option");
            SCReturnInt(-1);
    }
 
    SCReturnInt(0);
}