mirror of https://github.com/OISF/suricata
ICMP Seq Rule Keyword
Breno Silva
16 years ago
committed by
Victor Julien
parent
34e11e4784
commit
1d055b0e09
@ -0,0 +1,362 @@
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/* Copyright (c) 2009 Open Information Security Foundation */
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/** \file
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* \author Breno Silva <breno.silva@gmail.com>
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*/
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#include "suricata-common.h"
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#include "debug.h"
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#include "decode.h"
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#include "detect.h"
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#include "detect-icmp-seq.h"
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#include "util-byte.h"
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#include "util-unittest.h"
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#include "util-debug.h"
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#define PARSE_REGEX "^\\s*(\"\\s*)?([0-9]+)(\\s*\")?\\s*$"
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static pcre *parse_regex;
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static pcre_extra *parse_regex_study;
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int DetectIcmpSeqMatch(ThreadVars *, DetectEngineThreadCtx *, Packet *, Signature *, SigMatch *);
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int DetectIcmpSeqSetup(DetectEngineCtx *, Signature *, SigMatch *, char *);
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void DetectIcmpSeqRegisterTests(void);
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void DetectIcmpSeqFree(void *);
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/**
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* \brief Registration function for icmp_seq
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*/
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void DetectIcmpSeqRegister (void) {
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sigmatch_table[DETECT_ICMP_SEQ].name = "icmp_seq";
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sigmatch_table[DETECT_ICMP_SEQ].Match = DetectIcmpSeqMatch;
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sigmatch_table[DETECT_ICMP_SEQ].Setup = DetectIcmpSeqSetup;
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sigmatch_table[DETECT_ICMP_SEQ].Free = DetectIcmpSeqFree;
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sigmatch_table[DETECT_ICMP_SEQ].RegisterTests = DetectIcmpSeqRegisterTests;
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const char *eb;
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int eo;
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int opts = 0;
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parse_regex = pcre_compile(PARSE_REGEX, opts, &eb, &eo, NULL);
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if (parse_regex == NULL) {
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SCLogError(SC_PCRE_COMPILE_FAILED,"pcre compile of \"%s\" failed at offset %" PRId32 ": %s", PARSE_REGEX, eo, eb);
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goto error;
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}
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parse_regex_study = pcre_study(parse_regex, 0, &eb);
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if (eb != NULL) {
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SCLogError(SC_PCRE_STUDY_FAILED,"pcre study failed: %s", eb);
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goto error;
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}
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return;
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error:
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return;
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}
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/**
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* \brief This function is used to match icmp_seq rule option set on a packet
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*
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* \param t pointer to thread vars
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* \param det_ctx pointer to the pattern matcher thread
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* \param p pointer to the current packet
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* \param m pointer to the sigmatch that we will cast into DetectIcmpSeqData
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*
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* \retval 0 no match
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* \retval 1 match
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*/
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int DetectIcmpSeqMatch (ThreadVars *t, DetectEngineThreadCtx *det_ctx, Packet *p, Signature *s, SigMatch *m) {
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uint16_t seqn;
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DetectIcmpSeqData *iseq = (DetectIcmpSeqData *)m->ctx;
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if (PKT_IS_ICMPV4(p)) {
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switch (ICMPV4_GET_TYPE(p)){
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case ICMP_ECHOREPLY:
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case ICMP_ECHO:
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case ICMP_TIMESTAMP:
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case ICMP_TIMESTAMPREPLY:
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case ICMP_INFO_REQUEST:
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case ICMP_INFO_REPLY:
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case ICMP_ADDRESS:
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case ICMP_ADDRESSREPLY:
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seqn = ICMPV4_GET_SEQ(p);
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break;
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default:
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SCLogDebug("Packet has no seq field");
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return 0;
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}
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} else if (PKT_IS_ICMPV6(p)) {
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switch (ICMPV6_GET_TYPE(p)) {
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case ICMP6_ECHO_REQUEST:
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case ICMP6_ECHO_REPLY:
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seqn = ICMPV6_GET_SEQ(p);
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break;
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default:
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SCLogDebug("Packet has no seq field");
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return 0;
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}
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} else {
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SCLogDebug("Packet not ICMPV4 nor ICMPV6");
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return 0;
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}
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if (seqn == iseq->seq) return 1;
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return 0;
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}
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/**
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* \brief This function is used to parse icmp_seq option passed via icmp_seq: keyword
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*
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* \param icmpseqstr Pointer to the user provided icmp_seq options
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*
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* \retval iseq pointer to DetectIcmpSeqData on success
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* \retval NULL on failure
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*/
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DetectIcmpSeqData *DetectIcmpSeqParse (char *icmpseqstr) {
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DetectIcmpSeqData *iseq = NULL;
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char *substr[3] = {NULL, NULL, NULL};
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#define MAX_SUBSTRINGS 30
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int ret = 0, res = 0;
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int ov[MAX_SUBSTRINGS];
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int i;
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const char *str_ptr;
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ret = pcre_exec(parse_regex, parse_regex_study, icmpseqstr, strlen(icmpseqstr), 0, 0, ov, MAX_SUBSTRINGS);
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if (ret < 1 || ret > 4) {
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SCLogError(SC_PCRE_MATCH_FAILED,"Parse error %s", icmpseqstr);
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goto error;
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}
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for (i = 1; i < ret; i++) {
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res = pcre_get_substring((char *)icmpseqstr, ov, MAX_SUBSTRINGS, i, &str_ptr);
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if (res < 0) {
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SCLogError(SC_PCRE_GET_SUBSTRING_FAILED,"pcre_get_substring failed");
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goto error;
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}
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substr[i-1] = (char *)str_ptr;
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}
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iseq = malloc(sizeof(DetectIcmpSeqData));
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if (iseq == NULL) {
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SCLogError(SC_ERR_MEM_ALLOC, "Error allocating memory");
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goto error;
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}
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iseq->seq = 0;
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if (strlen(substr[0]) != 0) {
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if (substr[2] == NULL) {
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SCLogError(SC_ERR_MISSING_QUOTE,"Missing quote in input");
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goto error;
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}
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} else {
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if (substr[2] != NULL) {
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SCLogError(SC_ERR_MISSING_QUOTE,"Missing quote in input");
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goto error;
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}
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}
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ByteExtractStringUint16(&iseq->seq, 10, 0, substr[1]);
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for (i = 0; i < 3; i++) {
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if (substr[i] != NULL) free(substr[i]);
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}
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return iseq;
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error:
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for (i = 0; i < 3; i++) {
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if (substr[i] != NULL) free(substr[i]);
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}
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if (iseq != NULL) DetectIcmpSeqFree(iseq);
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return NULL;
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}
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/**
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* \brief this function is used to add the parsed icmp_seq data into the current signature
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*
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* \param de_ctx pointer to the Detection Engine Context
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* \param s pointer to the Current Signature
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* \param m pointer to the Current SigMatch
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* \param icmpseqstr pointer to the user provided icmp_seq option
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*
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* \retval 0 on Success
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* \retval -1 on Failure
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*/
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int DetectIcmpSeqSetup (DetectEngineCtx *de_ctx, Signature *s, SigMatch *m, char *icmpseqstr) {
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DetectIcmpSeqData *iseq = NULL;
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SigMatch *sm = NULL;
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iseq = DetectIcmpSeqParse(icmpseqstr);
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if (iseq == NULL) goto error;
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sm = SigMatchAlloc();
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if (sm == NULL) goto error;
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sm->type = DETECT_ICMP_SEQ;
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sm->ctx = (void *)iseq;
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SigMatchAppend(s, m, sm);
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return 0;
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error:
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if (iseq != NULL) DetectIcmpSeqFree(iseq);
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if (sm != NULL) free(sm);
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return -1;
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}
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/**
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* \brief this function will free memory associated with DetectIcmpSeqData
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*
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* \param ptr pointer to DetectIcmpSeqData
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*/
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void DetectIcmpSeqFree (void *ptr) {
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DetectIcmpSeqData *iseq = (DetectIcmpSeqData *)ptr;
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free(iseq);
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}
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#ifdef UNITTESTS
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#include "detect-parse.h"
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#include "detect-engine.h"
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#include "detect-engine-mpm.h"
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/**
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* \test DetectIcmpSeqParseTest01 is a test for setting a valid icmp_seq value
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*/
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int DetectIcmpSeqParseTest01 (void) {
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DetectIcmpSeqData *iseq = NULL;
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iseq = DetectIcmpSeqParse("300");
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if (iseq != NULL && iseq->seq == 300) {
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DetectIcmpSeqFree(iseq);
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return 1;
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}
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return 0;
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}
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/**
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* \test DetectIcmpSeqParseTest02 is a test for setting a valid icmp_seq value
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* with spaces all around
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*/
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int DetectIcmpSeqParseTest02 (void) {
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DetectIcmpSeqData *iseq = NULL;
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iseq = DetectIcmpSeqParse(" 300 ");
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if (iseq != NULL && iseq->seq == 300) {
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DetectIcmpSeqFree(iseq);
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return 1;
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}
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return 0;
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}
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/**
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* \test DetectIcmpSeqParseTest03 is a test for setting an invalid icmp_seq value
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*/
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int DetectIcmpSeqParseTest03 (void) {
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DetectIcmpSeqData *iseq = NULL;
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iseq = DetectIcmpSeqParse("badc");
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if (iseq != NULL) {
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DetectIcmpSeqFree(iseq);
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return 1;
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}
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return 0;
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}
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/**
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* \test DetectIcmpSeqMatchTest01 is a test for checking the working of
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* icmp_seq keyword by creating 2 rules and matching a crafted packet
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* against them. Only the first one shall trigger.
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*/
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int DetectIcmpSeqMatchTest01 (void) {
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int result = 0;
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uint8_t raw_icmpv4[] = {
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0x08, 0x00, 0x42, 0xb4, 0x02, 0x00, 0x08, 0xa8,
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0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
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0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70,
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0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x61,
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0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69};
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Packet p;
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Signature *s = NULL;
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DecodeThreadVars dtv;
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ThreadVars th_v;
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DetectEngineThreadCtx *det_ctx = NULL;
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IPV4Hdr ip4h;
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memset(&p, 0, sizeof(Packet));
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memset(&ip4h, 0, sizeof(IPV4Hdr));
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memset(&dtv, 0, sizeof(DecodeThreadVars));
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memset(&th_v, 0, sizeof(ThreadVars));
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FlowInitConfig(FLOW_QUIET);
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p.src.family = AF_INET;
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p.dst.family = AF_INET;
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p.src.addr_data32[0] = 0x01020304;
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p.dst.addr_data32[0] = 0x04030201;
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ip4h.ip_src.s_addr = p.src.addr_data32[0];
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ip4h.ip_dst.s_addr = p.dst.addr_data32[0];
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p.ip4h = &ip4h;
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DecodeICMPV4(&th_v, &dtv, &p, raw_icmpv4, sizeof(raw_icmpv4), NULL);
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DetectEngineCtx *de_ctx = DetectEngineCtxInit();
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if (de_ctx == NULL) {
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goto end;
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}
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de_ctx->flags |= DE_QUIET;
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s = de_ctx->sig_list = SigInit(de_ctx, "alert icmp any any -> any any (icmp_seq:2216; sid:1;)");
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if (s == NULL) {
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goto end;
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}
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s = s->next = SigInit(de_ctx, "alert icmp any any -> any any (icmp_seq:5000; sid:2;)");
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if (s == NULL) {
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goto end;
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}
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SigGroupBuild(de_ctx);
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DetectEngineThreadCtxInit(&th_v, (void *)de_ctx, (void *)&det_ctx);
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SigMatchSignatures(&th_v, de_ctx, det_ctx, &p);
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if (PacketAlertCheck(&p, 1) == 0) {
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printf("sid 1 did not alert, but should have: ");
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goto cleanup;
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} else if (PacketAlertCheck(&p, 2)) {
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printf("sid 2 alerted, but should not have: ");
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goto cleanup;
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}
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result = 1;
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cleanup:
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SigGroupCleanup(de_ctx);
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SigCleanSignatures(de_ctx);
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DetectEngineThreadCtxDeinit(&th_v, (void *)det_ctx);
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DetectEngineCtxFree(de_ctx);
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FlowShutdown();
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end:
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return result;
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}
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#endif /* UNITTESTS */
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void DetectIcmpSeqRegisterTests (void) {
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#ifdef UNITTESTS
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UtRegisterTest("DetectIcmpSeqParseTest01", DetectIcmpSeqParseTest01, 1);
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UtRegisterTest("DetectIcmpSeqParseTest02", DetectIcmpSeqParseTest02, 1);
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UtRegisterTest("DetectIcmpSeqParseTest03", DetectIcmpSeqParseTest03, 0);
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UtRegisterTest("DetectIcmpSeqMatchTest01", DetectIcmpSeqMatchTest01, 1);
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#endif /* UNITTESTS */
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}
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@ -0,0 +1,17 @@
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/* Copyright (c) 2009 Open Information Security Foundation */
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/** \file
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* \author Breno Silva <breno.silva@gmail.com>
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*/
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#ifndef __DETECT_ICMP_SEQ_H__
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#define __DETECT_ICMP_SEQ_H__
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typedef struct DetectIcmpSeqData_ {
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uint16_t seq;
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} DetectIcmpSeqData;
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/* prototypes */
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void DetectIcmpSeqRegister(void);
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#endif /* __DETECT_ICMP_SEQ__ */
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