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.
suricata/src/detect-distance.c

127 lines
4.0 KiB
C

/* DISTANCE part of the detection engine. */
#include "suricata-common.h"
#include "decode.h"
#include "detect.h"
#include "detect-parse.h"
#include "detect-content.h"
#include "detect-uricontent.h"
#include "flow-var.h"
#include "util-debug.h"
static int DetectDistanceSetup(DetectEngineCtx *, Signature *, char *);
void DetectDistanceRegister (void) {
sigmatch_table[DETECT_DISTANCE].name = "distance";
sigmatch_table[DETECT_DISTANCE].Match = NULL;
sigmatch_table[DETECT_DISTANCE].Setup = DetectDistanceSetup;
sigmatch_table[DETECT_DISTANCE].Free = NULL;
sigmatch_table[DETECT_DISTANCE].RegisterTests = NULL;
sigmatch_table[DETECT_DISTANCE].flags |= SIGMATCH_PAYLOAD;
}
static int DetectDistanceSetup (DetectEngineCtx *de_ctx, Signature *s, char *distancestr)
{
char *str = distancestr;
char dubbed = 0;
/* strip "'s */
if (distancestr[0] == '\"' && distancestr[strlen(distancestr)-1] == '\"') {
str = SCStrdup(distancestr+1);
str[strlen(distancestr)-2] = '\0';
dubbed = 1;
}
/** Search for the first previous DetectContent
* SigMatch (it can be the same as this one) */
SigMatch *pm = SigMatchGetLastPattern(s);
if (pm == NULL) {
SCLogError(SC_ERR_DISTANCE_MISSING_CONTENT, "depth needs two preceeding content (or uricontent) options");
if (dubbed) SCFree(str);
return -1;
}
DetectUricontentData *ud = NULL;
DetectContentData *cd = NULL;
switch (pm->type) {
case DETECT_URICONTENT:
ud = (DetectUricontentData *)pm->ctx;
if (ud == NULL) {
SCLogError(SC_ERR_DISTANCE_MISSING_CONTENT, "Unknown previous keyword!\n");
goto error;
}
ud->distance = strtol(str, NULL, 10);
ud->flags |= DETECT_URICONTENT_DISTANCE;
if (ud->flags & DETECT_URICONTENT_WITHIN) {
if (ud->distance + ud->uricontent_len > ud->within) {
ud->within = ud->distance + ud->uricontent_len;
}
}
pm = DetectUricontentGetLastPattern(s->umatch_tail->prev);
if (pm == NULL) {
SCLogError(SC_ERR_DISTANCE_MISSING_CONTENT, "distance needs two preceeding content options");
goto error;
}
if (pm->type == DETECT_URICONTENT) {
ud = (DetectUricontentData *)pm->ctx;
ud->flags |= DETECT_URICONTENT_RELATIVE_NEXT;
} else {
SCLogError(SC_ERR_RULE_KEYWORD_UNKNOWN, "Unknown previous-previous keyword!");
goto error;
}
break;
case DETECT_CONTENT:
cd = (DetectContentData *)pm->ctx;
if (cd == NULL) {
SCLogError(SC_ERR_DISTANCE_MISSING_CONTENT, "Unknown previous keyword!\n");
goto error;
}
cd->distance = strtol(str, NULL, 10);
cd->flags |= DETECT_CONTENT_DISTANCE;
if (cd->flags & DETECT_CONTENT_WITHIN) {
if (cd->distance + cd->content_len > cd->within) {
cd->within = cd->distance + cd->content_len;
}
}
pm = DetectContentGetLastPattern(s->pmatch_tail->prev);
if (pm == NULL) {
SCLogError(SC_ERR_DISTANCE_MISSING_CONTENT, "distance needs two preceeding content options");
goto error;
}
if (pm->type == DETECT_CONTENT) {
cd = (DetectContentData *)pm->ctx;
cd->flags |= DETECT_CONTENT_RELATIVE_NEXT;
} else {
SCLogError(SC_ERR_RULE_KEYWORD_UNKNOWN, "Unknown previous-previous keyword!");
goto error;
}
break;
default:
SCLogError(SC_ERR_DISTANCE_MISSING_CONTENT, "distance needs two preceeding content (or uricontent) options");
if (dubbed) SCFree(str);
return -1;
break;
}
if (dubbed) SCFree(str);
return 0;
error:
if (dubbed) SCFree(str);
return -1;
}