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