mirror of https://github.com/OISF/suricata
You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
357 lines
13 KiB
C
357 lines
13 KiB
C
/* Copyright (C) 2007-2010 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>
|
|
* \author Anoop Saldanha <poonaatsoc@gmail.com>
|
|
*
|
|
* Implements the offset keyword.
|
|
*/
|
|
|
|
#include "suricata-common.h"
|
|
|
|
#include "decode.h"
|
|
|
|
#include "detect.h"
|
|
#include "detect-parse.h"
|
|
#include "detect-content.h"
|
|
#include "detect-uricontent.h"
|
|
#include "app-layer.h"
|
|
|
|
#include "flow-var.h"
|
|
|
|
#include "util-debug.h"
|
|
|
|
static int DetectOffsetSetup (DetectEngineCtx *, Signature *, char *);
|
|
|
|
void DetectOffsetRegister (void) {
|
|
sigmatch_table[DETECT_OFFSET].name = "offset";
|
|
sigmatch_table[DETECT_OFFSET].Match = NULL;
|
|
sigmatch_table[DETECT_OFFSET].Setup = DetectOffsetSetup;
|
|
sigmatch_table[DETECT_OFFSET].Free = NULL;
|
|
sigmatch_table[DETECT_OFFSET].RegisterTests = NULL;
|
|
|
|
sigmatch_table[DETECT_OFFSET].flags |= SIGMATCH_PAYLOAD;
|
|
}
|
|
|
|
int DetectOffsetSetup (DetectEngineCtx *de_ctx, Signature *s, char *offsetstr)
|
|
{
|
|
char *str = offsetstr;
|
|
char dubbed = 0;
|
|
SigMatch *pm = NULL;
|
|
|
|
/* strip "'s */
|
|
if (offsetstr[0] == '\"' && offsetstr[strlen(offsetstr)-1] == '\"') {
|
|
str = SCStrdup(offsetstr+1);
|
|
if (str == NULL)
|
|
goto error;
|
|
str[strlen(offsetstr)-2] = '\0';
|
|
dubbed = 1;
|
|
}
|
|
|
|
switch (s->alproto) {
|
|
case ALPROTO_DCERPC:
|
|
/* add to the latest "content" keyword from either dmatch or pmatch */
|
|
pm = SigMatchGetLastSMFromLists(s, 4,
|
|
DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_DMATCH],
|
|
DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_PMATCH]);
|
|
if (pm == NULL) {
|
|
SCLogError(SC_ERR_WITHIN_MISSING_CONTENT, "offset needs"
|
|
"preceeding content option for dcerpc sig");
|
|
if (dubbed)
|
|
SCFree(str);
|
|
return -1;
|
|
}
|
|
|
|
break;
|
|
|
|
default:
|
|
pm = SigMatchGetLastSMFromLists(s, 14,
|
|
DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_PMATCH],
|
|
DETECT_URICONTENT, s->sm_lists_tail[DETECT_SM_LIST_UMATCH],
|
|
DETECT_AL_HTTP_CLIENT_BODY, s->sm_lists_tail[DETECT_SM_LIST_HCBDMATCH],
|
|
DETECT_AL_HTTP_HEADER, s->sm_lists_tail[DETECT_SM_LIST_HHDMATCH],
|
|
DETECT_AL_HTTP_RAW_HEADER, s->sm_lists_tail[DETECT_SM_LIST_HRHDMATCH],
|
|
DETECT_AL_HTTP_METHOD, s->sm_lists_tail[DETECT_SM_LIST_HMDMATCH],
|
|
DETECT_AL_HTTP_COOKIE, s->sm_lists_tail[DETECT_SM_LIST_HCDMATCH]);
|
|
if (pm == NULL) {
|
|
SCLogError(SC_ERR_WITHIN_MISSING_CONTENT, "offset needs"
|
|
"preceeding content or uricontent option, http_client_body "
|
|
"http_header, http_raw_header, http_method or "
|
|
"http_cookie option");
|
|
if (dubbed)
|
|
SCFree(str);
|
|
return -1;
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
/* we can remove this switch now with the unified structure */
|
|
DetectContentData *ud = NULL;
|
|
DetectContentData *cd = NULL;
|
|
switch (pm->type) {
|
|
case DETECT_URICONTENT:
|
|
ud = (DetectContentData *)pm->ctx;
|
|
if (ud == NULL) {
|
|
SCLogError(SC_ERR_INVALID_ARGUMENT, "invalid argument");
|
|
if (dubbed)
|
|
SCFree(str);
|
|
return -1;
|
|
}
|
|
|
|
if (ud->flags & DETECT_CONTENT_NEGATED) {
|
|
if (ud->flags & DETECT_CONTENT_FAST_PATTERN) {
|
|
SCLogError(SC_ERR_INVALID_SIGNATURE, "You can't have a relative "
|
|
"negated keyword set along with a fast_pattern");
|
|
goto error;
|
|
}
|
|
} else {
|
|
if (ud->flags & DETECT_CONTENT_FAST_PATTERN_ONLY) {
|
|
SCLogError(SC_ERR_INVALID_SIGNATURE, "You can't have a relative "
|
|
"keyword set along with a fast_pattern:only;");
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
ud->offset = (uint32_t)atoi(str);
|
|
if (ud->depth != 0) {
|
|
if (ud->depth < ud->content_len) {
|
|
SCLogDebug("depth increased to %"PRIu32" to match pattern len",
|
|
ud->content_len);
|
|
ud->depth = ud->content_len;
|
|
}
|
|
/* Updating the depth as is relative to the offset */
|
|
ud->depth += ud->offset;
|
|
}
|
|
|
|
ud->flags |= DETECT_CONTENT_OFFSET;
|
|
|
|
break;
|
|
|
|
case DETECT_CONTENT:
|
|
cd = (DetectContentData *)pm->ctx;
|
|
if (cd == NULL) {
|
|
SCLogError(SC_ERR_INVALID_ARGUMENT, "invalid argument");
|
|
if (dubbed)
|
|
SCFree(str);
|
|
return -1;
|
|
}
|
|
|
|
if (cd->flags & DETECT_CONTENT_NEGATED) {
|
|
if (cd->flags & DETECT_CONTENT_FAST_PATTERN) {
|
|
SCLogError(SC_ERR_INVALID_SIGNATURE, "You can't have a relative "
|
|
"negated keyword set along with a fast_pattern");
|
|
goto error;
|
|
}
|
|
} else {
|
|
if (cd->flags & DETECT_CONTENT_FAST_PATTERN_ONLY) {
|
|
SCLogError(SC_ERR_INVALID_SIGNATURE, "You can't have a relative "
|
|
"keyword set along with a fast_pattern:only;");
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
cd->offset = (uint32_t)atoi(str);
|
|
if (cd->depth != 0) {
|
|
if (cd->depth < cd->content_len) {
|
|
SCLogDebug("depth increased to %"PRIu32" to match pattern len",
|
|
cd->content_len);
|
|
cd->depth = cd->content_len;
|
|
}
|
|
/* Updating the depth as is relative to the offset */
|
|
cd->depth += cd->offset;
|
|
}
|
|
|
|
cd->flags |= DETECT_CONTENT_OFFSET;
|
|
|
|
break;
|
|
|
|
case DETECT_AL_HTTP_CLIENT_BODY:
|
|
cd = (DetectContentData *)pm->ctx;
|
|
if (cd->flags & DETECT_CONTENT_NEGATED) {
|
|
if (cd->flags & DETECT_CONTENT_FAST_PATTERN) {
|
|
SCLogError(SC_ERR_INVALID_SIGNATURE, "You can't have a relative "
|
|
"negated keyword set along with a fast_pattern");
|
|
goto error;
|
|
}
|
|
} else {
|
|
if (cd->flags & DETECT_CONTENT_FAST_PATTERN_ONLY) {
|
|
SCLogError(SC_ERR_INVALID_SIGNATURE, "You can't have a relative "
|
|
"keyword set along with a fast_pattern:only;");
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
cd->offset = (uint32_t)atoi(str);
|
|
if (cd->depth != 0) {
|
|
if (cd->depth < cd->content_len) {
|
|
SCLogDebug("depth increased to %"PRIu32" to match pattern len",
|
|
cd->content_len);
|
|
cd->depth = cd->content_len;
|
|
}
|
|
/* Updating the depth as is relative to the offset */
|
|
cd->depth += cd->offset;
|
|
}
|
|
|
|
cd->flags |= DETECT_CONTENT_OFFSET;
|
|
|
|
break;
|
|
|
|
case DETECT_AL_HTTP_HEADER:
|
|
cd = (DetectContentData *)pm->ctx;
|
|
if (cd->flags & DETECT_CONTENT_NEGATED) {
|
|
if (cd->flags & DETECT_CONTENT_FAST_PATTERN) {
|
|
SCLogError(SC_ERR_INVALID_SIGNATURE, "You can't have a relative "
|
|
"negated keyword set along with a fast_pattern");
|
|
goto error;
|
|
}
|
|
} else {
|
|
if (cd->flags & DETECT_CONTENT_FAST_PATTERN_ONLY) {
|
|
SCLogError(SC_ERR_INVALID_SIGNATURE, "You can't have a relative "
|
|
"keyword set along with a fast_pattern:only;");
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
cd->offset = (uint32_t)atoi(str);
|
|
if (cd->depth != 0) {
|
|
if (cd->depth < cd->content_len) {
|
|
SCLogDebug("depth increased to %"PRIu32" to match pattern len",
|
|
cd->content_len);
|
|
cd->depth = cd->content_len;
|
|
}
|
|
/* Updating the depth as is relative to the offset */
|
|
cd->depth += cd->offset;
|
|
}
|
|
|
|
cd->flags |= DETECT_CONTENT_OFFSET;
|
|
|
|
break;
|
|
|
|
case DETECT_AL_HTTP_RAW_HEADER:
|
|
cd = (DetectContentData *)pm->ctx;
|
|
if (cd->flags & DETECT_CONTENT_NEGATED) {
|
|
if (cd->flags & DETECT_CONTENT_FAST_PATTERN) {
|
|
SCLogError(SC_ERR_INVALID_SIGNATURE, "You can't have a relative "
|
|
"negated keyword set along with a fast_pattern");
|
|
goto error;
|
|
}
|
|
} else {
|
|
if (cd->flags & DETECT_CONTENT_FAST_PATTERN_ONLY) {
|
|
SCLogError(SC_ERR_INVALID_SIGNATURE, "You can't have a relative "
|
|
"keyword set along with a fast_pattern:only;");
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
cd->offset = (uint32_t)atoi(str);
|
|
if (cd->depth != 0) {
|
|
if (cd->depth < cd->content_len) {
|
|
SCLogDebug("depth increased to %"PRIu32" to match pattern len",
|
|
cd->content_len);
|
|
cd->depth = cd->content_len;
|
|
}
|
|
/* Updating the depth as is relative to the offset */
|
|
cd->depth += cd->offset;
|
|
}
|
|
|
|
cd->flags |= DETECT_CONTENT_OFFSET;
|
|
|
|
break;
|
|
|
|
case DETECT_AL_HTTP_METHOD:
|
|
cd = (DetectContentData *)pm->ctx;
|
|
if (cd->flags & DETECT_CONTENT_NEGATED) {
|
|
if (cd->flags & DETECT_CONTENT_FAST_PATTERN) {
|
|
SCLogError(SC_ERR_INVALID_SIGNATURE, "You can't have a relative "
|
|
"negated keyword set along with a fast_pattern");
|
|
goto error;
|
|
}
|
|
} else {
|
|
if (cd->flags & DETECT_CONTENT_FAST_PATTERN_ONLY) {
|
|
SCLogError(SC_ERR_INVALID_SIGNATURE, "You can't have a relative "
|
|
"keyword set along with a fast_pattern:only;");
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
cd->offset = (uint32_t)atoi(str);
|
|
if (cd->depth != 0) {
|
|
if (cd->depth < cd->content_len) {
|
|
SCLogDebug("depth increased to %"PRIu32" to match pattern len",
|
|
cd->content_len);
|
|
cd->depth = cd->content_len;
|
|
}
|
|
/* Updating the depth as is relative to the offset */
|
|
cd->depth += cd->offset;
|
|
}
|
|
|
|
cd->flags |= DETECT_CONTENT_OFFSET;
|
|
|
|
break;
|
|
|
|
case DETECT_AL_HTTP_COOKIE:
|
|
cd = (DetectContentData *)pm->ctx;
|
|
if (cd->flags & DETECT_CONTENT_NEGATED) {
|
|
if (cd->flags & DETECT_CONTENT_FAST_PATTERN) {
|
|
SCLogError(SC_ERR_INVALID_SIGNATURE, "You can't have a relative "
|
|
"negated keyword set along with a fast_pattern");
|
|
goto error;
|
|
}
|
|
} else {
|
|
if (cd->flags & DETECT_CONTENT_FAST_PATTERN_ONLY) {
|
|
SCLogError(SC_ERR_INVALID_SIGNATURE, "You can't have a relative "
|
|
"keyword set along with a fast_pattern:only;");
|
|
goto error;
|
|
}
|
|
}
|
|
|
|
cd->offset = (uint32_t)atoi(str);
|
|
if (cd->depth != 0) {
|
|
if (cd->depth < cd->content_len) {
|
|
SCLogDebug("depth increased to %"PRIu32" to match pattern len",
|
|
cd->content_len);
|
|
cd->depth = cd->content_len;
|
|
}
|
|
/* Updating the depth as is relative to the offset */
|
|
cd->depth += cd->offset;
|
|
}
|
|
|
|
cd->flags |= DETECT_CONTENT_OFFSET;
|
|
|
|
break;
|
|
|
|
default:
|
|
SCLogError(SC_ERR_OFFSET_MISSING_CONTENT, "offset needs a preceeding"
|
|
" content or uricontent option");
|
|
goto error;
|
|
}
|
|
|
|
if (dubbed)
|
|
SCFree(str);
|
|
return 0;
|
|
|
|
error:
|
|
if (dubbed)
|
|
SCFree(str);
|
|
return -1;
|
|
}
|
|
|