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suricata/src/detect-csum.c

1068 lines
35 KiB
C

/* Copyright (C) 2007-2013 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 Anoop Saldanha <anoopsaldanha@gmail.com>
*
* Implements checksum keyword.
*/
#include "suricata-common.h"
#include "debug.h"
#include "decode.h"
#include "detect.h"
#include "detect-parse.h"
#include "detect-csum.h"
#include "util-unittest.h"
#include "util-debug.h"
#include "pkt-var.h"
#include "host.h"
#include "util-profiling.h"
/* prototypes for the "ipv4-csum" rule keyword */
static int DetectIPV4CsumMatch(DetectEngineThreadCtx *,
Packet *, const Signature *, const SigMatchCtx *);
static int DetectIPV4CsumSetup(DetectEngineCtx *, Signature *, const char *);
static void DetectIPV4CsumFree(DetectEngineCtx *, void *);
/* prototypes for the "tcpv4-csum" rule keyword */
static int DetectTCPV4CsumMatch(DetectEngineThreadCtx *,
Packet *, const Signature *, const SigMatchCtx *);
static int DetectTCPV4CsumSetup(DetectEngineCtx *, Signature *, const char *);
static void DetectTCPV4CsumFree(DetectEngineCtx *, void *);
/* prototypes for the "tcpv6-csum" rule keyword */
static int DetectTCPV6CsumMatch(DetectEngineThreadCtx *,
Packet *, const Signature *, const SigMatchCtx *);
static int DetectTCPV6CsumSetup(DetectEngineCtx *, Signature *, const char *);
static void DetectTCPV6CsumFree(DetectEngineCtx *, void *);
/* prototypes for the "udpv4-csum" rule keyword */
static int DetectUDPV4CsumMatch(DetectEngineThreadCtx *,
Packet *, const Signature *, const SigMatchCtx *);
static int DetectUDPV4CsumSetup(DetectEngineCtx *, Signature *, const char *);
static void DetectUDPV4CsumFree(DetectEngineCtx *, void *);
/* prototypes for the "udpv6-csum" rule keyword */
static int DetectUDPV6CsumMatch(DetectEngineThreadCtx *,
Packet *, const Signature *, const SigMatchCtx *);
static int DetectUDPV6CsumSetup(DetectEngineCtx *, Signature *, const char *);
static void DetectUDPV6CsumFree(DetectEngineCtx *de_ctx, void *);
/* prototypes for the "icmpv4-csum" rule keyword */
static int DetectICMPV4CsumMatch(DetectEngineThreadCtx *,
Packet *, const Signature *, const SigMatchCtx *);
static int DetectICMPV4CsumSetup(DetectEngineCtx *, Signature *, const char *);
static void DetectICMPV4CsumFree(DetectEngineCtx *, void *);
/* prototypes for the "icmpv6-csum" rule keyword */
static int DetectICMPV6CsumMatch(DetectEngineThreadCtx *,
Packet *, const Signature *, const SigMatchCtx *);
static int DetectICMPV6CsumSetup(DetectEngineCtx *, Signature *, const char *);
static void DetectICMPV6CsumFree(DetectEngineCtx *, void *);
#ifdef UNITTESTS
static void DetectCsumRegisterTests(void);
#endif
/**
* \brief Registers handlers for all the checksum keywords. The checksum
* keywords that are registered are ipv4-sum, tcpv4-csum, tcpv6-csum,
* udpv4-csum, udpv6-csum, icmpv4-csum and icmpv6-csum.
*
* Each of the checksum keywords implemented here takes 2 arguments -
* "valid" or "invalid". If the rule keyword in the signature is
* specified as "valid", the Match function would return TRUE if the
* checksum for that particular packet and protocol is valid. Similarly
* for "invalid".
*
* The Setup functions takes 4 arguments -
*
* DetectEngineCtx * (de_ctx) - A pointer to the detection engine context
* Signature *(s) - Pointer to signature for the current Signature being
* parsed from the rules
* SigMatchCtx * (m) - Pointer to the head of the SigMatchs added to the
* current Signature being parsed
* char * (csum_str) - Pointer to a string holding the keyword value
*
* The Setup function returns 0 if it successfully parses the keyword
* value, and -1 otherwise.
*
* The Match function takes 5 arguments -
*
* ThreadVars * (t) - Pointer to the tv for the detection module instance
* DetectEngineThreadCtx * (det_ctx) - Pointer to the detection engine
* thread context
* Packet * (p) - Pointer to the Packet currently being handled
* Signature * (s) - Pointer to the Signature, the packet is being
* currently matched with
* SigMatchCtx * (m) - Pointer to the keyword structure from the above
* Signature, the Packet is being currently matched
* with
*
* The Match function returns 1 if the Packet contents match the keyword,
* and 0 otherwise
*
* The Free function takes a single argument -
*
* void * (ptr) - Pointer to the DetectCsumData for a keyword
*/
void DetectCsumRegister (void)
{
sigmatch_table[DETECT_IPV4_CSUM].name = "ipv4-csum";
sigmatch_table[DETECT_IPV4_CSUM].Match = DetectIPV4CsumMatch;
sigmatch_table[DETECT_IPV4_CSUM].Setup = DetectIPV4CsumSetup;
sigmatch_table[DETECT_IPV4_CSUM].Free = DetectIPV4CsumFree;
#ifdef UNITTESTS
sigmatch_table[DETECT_IPV4_CSUM].RegisterTests = DetectCsumRegisterTests;
#endif
sigmatch_table[DETECT_TCPV4_CSUM].name = "tcpv4-csum";
sigmatch_table[DETECT_TCPV4_CSUM].Match = DetectTCPV4CsumMatch;
sigmatch_table[DETECT_TCPV4_CSUM].Setup = DetectTCPV4CsumSetup;
sigmatch_table[DETECT_TCPV4_CSUM].Free = DetectTCPV4CsumFree;
sigmatch_table[DETECT_TCPV6_CSUM].name = "tcpv6-csum";
sigmatch_table[DETECT_TCPV6_CSUM].Match = DetectTCPV6CsumMatch;
sigmatch_table[DETECT_TCPV6_CSUM].Setup = DetectTCPV6CsumSetup;
sigmatch_table[DETECT_TCPV6_CSUM].Free = DetectTCPV6CsumFree;
sigmatch_table[DETECT_UDPV4_CSUM].name = "udpv4-csum";
sigmatch_table[DETECT_UDPV4_CSUM].Match = DetectUDPV4CsumMatch;
sigmatch_table[DETECT_UDPV4_CSUM].Setup = DetectUDPV4CsumSetup;
sigmatch_table[DETECT_UDPV4_CSUM].Free = DetectUDPV4CsumFree;
sigmatch_table[DETECT_UDPV6_CSUM].name = "udpv6-csum";
sigmatch_table[DETECT_UDPV6_CSUM].Match = DetectUDPV6CsumMatch;
sigmatch_table[DETECT_UDPV6_CSUM].Setup = DetectUDPV6CsumSetup;
sigmatch_table[DETECT_UDPV6_CSUM].Free = DetectUDPV6CsumFree;
sigmatch_table[DETECT_ICMPV4_CSUM].name = "icmpv4-csum";
sigmatch_table[DETECT_ICMPV4_CSUM].Match = DetectICMPV4CsumMatch;
sigmatch_table[DETECT_ICMPV4_CSUM].Setup = DetectICMPV4CsumSetup;
sigmatch_table[DETECT_ICMPV4_CSUM].Free = DetectICMPV4CsumFree;
sigmatch_table[DETECT_ICMPV6_CSUM].name = "icmpv6-csum";
sigmatch_table[DETECT_ICMPV6_CSUM].Match = DetectICMPV6CsumMatch;
sigmatch_table[DETECT_ICMPV6_CSUM].Setup = DetectICMPV6CsumSetup;
sigmatch_table[DETECT_ICMPV6_CSUM].Free = DetectICMPV6CsumFree;
}
/**
* \brief Validates and parses the argument supplied with the checksum keyword.
* Accepts strings both with and without quotes, i.e. valid, \"valid\",
* invalid and \"invalid\"
*
* \param key Pointer to a const character string holding the csum keyword value
* \param cd Pointer to the DetectCsumData structure that holds the keyword
* value sent as argument
*
* \retval 1 the keyvalue has been parsed successfully
* \retval 0 error
*/
static int DetectCsumParseArg(const char *key, DetectCsumData *cd)
{
char *str;
if (key[0] == '\"' && key[strlen(key) - 1] == '\"') {
str = SCStrdup(key + 1);
if (unlikely(str == NULL)) {
goto error;
}
str[strlen(key) - 2] = '\0';
} else {
str = SCStrdup(key);
if (unlikely(str == NULL)) {
goto error;
}
}
if (strcasecmp(str, DETECT_CSUM_VALID) == 0 ||
strcasecmp(str, DETECT_CSUM_INVALID) == 0) {
cd->valid = (strcasecmp(key, DETECT_CSUM_VALID) == 0);
SCFree(str);
return 1;
}
error:
if (str != NULL)
SCFree(str);
return 0;
}
/**
* \brief Checks if the packet sent as the argument, has a valid or invalid
* ipv4 checksum, based on whether ipv4-csum option for this rule
* has been supplied with "valid" or "invalid" argument
*
* \param t Pointer to the tv for this detection module instance
* \param det_ctx Pointer to the detection engine thread context
* \param p Pointer to the Packet currently being matched
* \param s Pointer to the Signature, the packet is being currently
* matched with
* \param m Pointer to the keyword_structure(SigMatch) from the above
* Signature, the Packet is being currently matched with
*
* \retval 1 if the Packet contents match the keyword option; 0 otherwise
*/
static int DetectIPV4CsumMatch(DetectEngineThreadCtx *det_ctx,
Packet *p, const Signature *s, const SigMatchCtx *ctx)
{
const DetectCsumData *cd = (const DetectCsumData *)ctx;
if (p->ip4h == NULL || PKT_IS_PSEUDOPKT(p))
return 0;
if (p->flags & PKT_IGNORE_CHECKSUM) {
return cd->valid;
}
if (p->level3_comp_csum == -1)
p->level3_comp_csum = IPV4Checksum((uint16_t *)p->ip4h,
IPV4_GET_HLEN(p),
p->ip4h->ip_csum);
if (p->level3_comp_csum == 0 && cd->valid == 1)
return 1;
else if (p->level3_comp_csum != 0 && cd->valid == 0)
return 1;
else
return 0;
}
/**
* \brief Creates a SigMatch for the ipv4-csum keyword being sent as argument,
* and appends it to the Signature(s). Accepts 2 values for the
* keyword - "valid" and "invalid", both with and without quotes
*
* \param de_ctx Pointer to the detection engine context
* \param s Pointer to signature for the current Signature being parsed
* from the rules
* \param csum_str Pointer to the string holding the keyword value
*
* \retval 0 on success, -1 on failure
*/
static int DetectIPV4CsumSetup(DetectEngineCtx *de_ctx, Signature *s, const char *csum_str)
{
DetectCsumData *cd = NULL;
SigMatch *sm = NULL;
//printf("DetectCsumSetup: \'%s\'\n", csum_str);
sm = SigMatchAlloc();
if (sm == NULL)
goto error;
sm->type = DETECT_IPV4_CSUM;
if ( (cd = SCMalloc(sizeof(DetectCsumData))) == NULL)
goto error;
memset(cd, 0, sizeof(DetectCsumData));
if (DetectCsumParseArg(csum_str, cd) == 0)
goto error;
sm->ctx = (SigMatchCtx *)cd;
SigMatchAppendSMToList(s, sm, DETECT_SM_LIST_MATCH);
return 0;
error:
if (cd != NULL) DetectIPV4CsumFree(de_ctx, cd);
if (sm != NULL) SCFree(sm);
return -1;
}
static void DetectIPV4CsumFree(DetectEngineCtx *de_ctx, void *ptr)
{
DetectCsumData *cd = (DetectCsumData *)ptr;
if (cd != NULL)
SCFree(cd);
return;
}
/**
* \brief Checks if the packet sent as the argument, has a valid or invalid
* tcpv4 checksum, based on whether tcpv4-csum option for this rule
* has been supplied with "valid" or "invalid" argument
*
* \param t Pointer to the tv for this detection module instance
* \param det_ctx Pointer to the detection engine thread context
* \param p Pointer to the Packet currently being matched
* \param s Pointer to the Signature, the packet is being currently
* matched with
* \param m Pointer to the keyword_structure(SigMatch) from the above
* Signature, the Packet is being currently matched with
*
* \retval 1 if the Packet contents match the keyword option; 0 otherwise
*/
static int DetectTCPV4CsumMatch(DetectEngineThreadCtx *det_ctx,
Packet *p, const Signature *s, const SigMatchCtx *ctx)
{
const DetectCsumData *cd = (const DetectCsumData *)ctx;
if (p->ip4h == NULL || p->tcph == NULL || p->proto != IPPROTO_TCP || PKT_IS_PSEUDOPKT(p))
return 0;
if (p->flags & PKT_IGNORE_CHECKSUM) {
return cd->valid;
}
if (p->level4_comp_csum == -1)
p->level4_comp_csum = TCPChecksum(p->ip4h->s_ip_addrs,
(uint16_t *)p->tcph,
(p->payload_len +
TCP_GET_HLEN(p)),
p->tcph->th_sum);
if (p->level4_comp_csum == 0 && cd->valid == 1)
return 1;
else if (p->level4_comp_csum != 0 && cd->valid == 0)
return 1;
else
return 0;
}
/**
* \brief Creates a SigMatch for the tcpv4-csum keyword being sent as argument,
* and appends it to the Signature(s). Accepts 2 values for the
* keyword - "valid" and "invalid", both with and without quotes
*
* \param de_ctx Pointer to the detection engine context
* \param s Pointer to signature for the current Signature being parsed
* from the rules
* \param csum_str Pointer to the string holding the keyword value
*
* \retval 0 on success, -1 on failure
*/
static int DetectTCPV4CsumSetup(DetectEngineCtx *de_ctx, Signature *s, const char *csum_str)
{
DetectCsumData *cd = NULL;
SigMatch *sm = NULL;
//printf("DetectCsumSetup: \'%s\'\n", csum_str);
sm = SigMatchAlloc();
if (sm == NULL)
goto error;
sm->type = DETECT_TCPV4_CSUM;
if ( (cd = SCMalloc(sizeof(DetectCsumData))) == NULL)
goto error;
memset(cd, 0, sizeof(DetectCsumData));
if (DetectCsumParseArg(csum_str, cd) == 0)
goto error;
sm->ctx = (SigMatchCtx *)cd;
SigMatchAppendSMToList(s, sm, DETECT_SM_LIST_MATCH);
return 0;
error:
if (cd != NULL) DetectTCPV4CsumFree(de_ctx, cd);
if (sm != NULL) SCFree(sm);
return -1;
}
static void DetectTCPV4CsumFree(DetectEngineCtx *de_ctx, void *ptr)
{
DetectCsumData *cd = (DetectCsumData *)ptr;
if (cd != NULL)
SCFree(cd);
return;
}
/**
* \brief Checks if the packet sent as the argument, has a valid or invalid
* tcpv6 checksum, based on whether tcpv6-csum option for this rule
* has been supplied with "valid" or "invalid" argument
*
* \param t Pointer to the tv for this detection module instance
* \param det_ctx Pointer to the detection engine thread context
* \param p Pointer to the Packet currently being matched
* \param s Pointer to the Signature, the packet is being currently
* matched with
* \param m Pointer to the keyword_structure(SigMatch) from the above
* Signature, the Packet is being currently matched with
*
* \retval 1 if the Packet contents match the keyword option; 0 otherwise
*/
static int DetectTCPV6CsumMatch(DetectEngineThreadCtx *det_ctx,
Packet *p, const Signature *s, const SigMatchCtx *ctx)
{
const DetectCsumData *cd = (const DetectCsumData *)ctx;
if (p->ip6h == NULL || p->tcph == NULL || p->proto != IPPROTO_TCP || PKT_IS_PSEUDOPKT(p))
return 0;
if (p->flags & PKT_IGNORE_CHECKSUM) {
return cd->valid;
}
if (p->level4_comp_csum == -1)
p->level4_comp_csum = TCPV6Checksum(p->ip6h->s_ip6_addrs,
(uint16_t *)p->tcph,
(p->payload_len +
TCP_GET_HLEN(p)),
p->tcph->th_sum);
if (p->level4_comp_csum == 0 && cd->valid == 1)
return 1;
else if (p->level4_comp_csum != 0 && cd->valid == 0)
return 1;
else
return 0;
}
/**
* \brief Creates a SigMatch for the tcpv6-csum keyword being sent as argument,
* and appends it to the Signature(s). Accepts 2 values for the
* keyword - "valid" and "invalid", both with and without quotes
*
* \param de_ctx Pointer to the detection engine context
* \param s Pointer to signature for the current Signature being parsed
* from the rules
* \param csum_str Pointer to the string holding the keyword value
*
* \retval 0 on success, -1 on failure
*/
static int DetectTCPV6CsumSetup(DetectEngineCtx *de_ctx, Signature *s, const char *csum_str)
{
DetectCsumData *cd = NULL;
SigMatch *sm = NULL;
//printf("DetectCsumSetup: \'%s\'\n", csum_str);
sm = SigMatchAlloc();
if (sm == NULL)
goto error;
sm->type = DETECT_TCPV6_CSUM;
if ( (cd = SCMalloc(sizeof(DetectCsumData))) == NULL)
goto error;
memset(cd, 0, sizeof(DetectCsumData));
if (DetectCsumParseArg(csum_str, cd) == 0)
goto error;
sm->ctx = (SigMatchCtx *)cd;
SigMatchAppendSMToList(s, sm, DETECT_SM_LIST_MATCH);
return 0;
error:
if (cd != NULL) DetectTCPV6CsumFree(de_ctx, cd);
if (sm != NULL) SCFree(sm);
return -1;
}
static void DetectTCPV6CsumFree(DetectEngineCtx *de_ctx, void *ptr)
{
DetectCsumData *cd = (DetectCsumData *)ptr;
if (cd != NULL)
SCFree(cd);
return;
}
/**
* \brief Checks if the packet sent as the argument, has a valid or invalid
* udpv4 checksum, based on whether udpv4-csum option for this rule
* has been supplied with "valid" or "invalid" argument
*
* \param t Pointer to the tv for this detection module instance
* \param det_ctx Pointer to the detection engine thread context
* \param p Pointer to the Packet currently being matched
* \param s Pointer to the Signature, the packet is being currently
* matched with
* \param m Pointer to the keyword_structure(SigMatch) from the above
* Signature, the Packet is being currently matched with
*
* \retval 1 if the Packet contents match the keyword option; 0 otherwise
*/
static int DetectUDPV4CsumMatch(DetectEngineThreadCtx *det_ctx,
Packet *p, const Signature *s, const SigMatchCtx *ctx)
{
const DetectCsumData *cd = (const DetectCsumData *)ctx;
if (p->ip4h == NULL || p->udph == NULL || p->proto != IPPROTO_UDP || PKT_IS_PSEUDOPKT(p) || p->udph->uh_sum == 0)
return 0;
if (p->flags & PKT_IGNORE_CHECKSUM) {
return cd->valid;
}
if (p->level4_comp_csum == -1)
p->level4_comp_csum = UDPV4Checksum(p->ip4h->s_ip_addrs,
(uint16_t *)p->udph,
(p->payload_len +
UDP_HEADER_LEN),
p->udph->uh_sum);
if (p->level4_comp_csum == 0 && cd->valid == 1)
return 1;
else if (p->level4_comp_csum != 0 && cd->valid == 0)
return 1;
else
return 0;
}
/**
* \brief Creates a SigMatch for the udpv4-csum keyword being sent as argument,
* and appends it to the Signature(s). Accepts 2 values for the
* keyword - "valid" and "invalid", both with and without quotes
*
* \param de_ctx Pointer to the detection engine context
* \param s Pointer to signature for the current Signature being parsed
* from the rules
* \param csum_str Pointer to the string holding the keyword value
*
* \retval 0 on success, -1 on failure
*/
static int DetectUDPV4CsumSetup(DetectEngineCtx *de_ctx, Signature *s, const char *csum_str)
{
DetectCsumData *cd = NULL;
SigMatch *sm = NULL;
//printf("DetectCsumSetup: \'%s\'\n", csum_str);
sm = SigMatchAlloc();
if (sm == NULL)
goto error;
sm->type = DETECT_UDPV4_CSUM;
if ( (cd = SCMalloc(sizeof(DetectCsumData))) == NULL)
goto error;
memset(cd, 0, sizeof(DetectCsumData));
if (DetectCsumParseArg(csum_str, cd) == 0)
goto error;
sm->ctx = (SigMatchCtx *)cd;
SigMatchAppendSMToList(s, sm, DETECT_SM_LIST_MATCH);
return 0;
error:
if (cd != NULL) DetectUDPV4CsumFree(de_ctx, cd);
if (sm != NULL) SCFree(sm);
return -1;
}
static void DetectUDPV4CsumFree(DetectEngineCtx *de_ctx, void *ptr)
{
DetectCsumData *cd = (DetectCsumData *)ptr;
if (cd != NULL)
SCFree(cd);
return;
}
/**
* \brief Checks if the packet sent as the argument, has a valid or invalid
* udpv6 checksum, based on whether udpv6-csum option for this rule
* has been supplied with "valid" or "invalid" argument
*
* \param t Pointer to the tv for this detection module instance
* \param det_ctx Pointer to the detection engine thread context
* \param p Pointer to the Packet currently being matched
* \param s Pointer to the Signature, the packet is being currently
* matched with
* \param m Pointer to the keyword_structure(SigMatch) from the above
* Signature, the Packet is being currently matched with
*
* \retval 1 if the Packet contents match the keyword option; 0 otherwise
*/
static int DetectUDPV6CsumMatch(DetectEngineThreadCtx *det_ctx,
Packet *p, const Signature *s, const SigMatchCtx *ctx)
{
const DetectCsumData *cd = (const DetectCsumData *)ctx;
if (p->ip6h == NULL || p->udph == NULL || p->proto != IPPROTO_UDP || PKT_IS_PSEUDOPKT(p))
return 0;
if (p->flags & PKT_IGNORE_CHECKSUM) {
return cd->valid;
}
if (p->level4_comp_csum == -1)
p->level4_comp_csum = UDPV6Checksum(p->ip6h->s_ip6_addrs,
(uint16_t *)p->udph,
(p->payload_len +
UDP_HEADER_LEN),
p->udph->uh_sum);
if (p->level4_comp_csum == 0 && cd->valid == 1)
return 1;
else if (p->level4_comp_csum != 0 && cd->valid == 0)
return 1;
else
return 0;
}
/**
* \brief Creates a SigMatch for the udpv6-csum keyword being sent as argument,
* and appends it to the Signature(s). Accepts 2 values for the
* keyword - "valid" and "invalid", both with and without quotes
*
* \param de_ctx Pointer to the detection engine context
* \param s Pointer to signature for the current Signature being parsed
* from the rules
* \param csum_str Pointer to the string holding the keyword value
*
* \retval 0 on success, -1 on failure
*/
static int DetectUDPV6CsumSetup(DetectEngineCtx *de_ctx, Signature *s, const char *csum_str)
{
DetectCsumData *cd = NULL;
SigMatch *sm = NULL;
//printf("DetectCsumSetup: \'%s\'\n", csum_str);
sm = SigMatchAlloc();
if (sm == NULL)
goto error;
sm->type = DETECT_UDPV6_CSUM;
if ( (cd = SCMalloc(sizeof(DetectCsumData))) == NULL)
goto error;
memset(cd, 0, sizeof(DetectCsumData));
if (DetectCsumParseArg(csum_str, cd) == 0)
goto error;
sm->ctx = (void *)cd;
SigMatchAppendSMToList(s, sm, DETECT_SM_LIST_MATCH);
return 0;
error:
if (cd != NULL) DetectUDPV6CsumFree(de_ctx, cd);
if (sm != NULL) SCFree(sm);
return -1;
}
static void DetectUDPV6CsumFree(DetectEngineCtx *de_ctx, void *ptr)
{
DetectCsumData *cd = (DetectCsumData *)ptr;
if (cd != NULL)
SCFree(cd);
return;
}
/**
* \brief Checks if the packet sent as the argument, has a valid or invalid
* icmpv4 checksum, based on whether icmpv4-csum option for this rule
* has been supplied with "valid" or "invalid" argument
*
* \param t Pointer to the tv for this detection module instance
* \param det_ctx Pointer to the detection engine thread context
* \param p Pointer to the Packet currently being matched
* \param s Pointer to the Signature, the packet is being currently
* matched with
* \param m Pointer to the keyword_structure(SigMatch) from the above
* Signature, the Packet is being currently matched with
*
* \retval 1 if the Packet contents match the keyword option; 0 otherwise
*/
static int DetectICMPV4CsumMatch(DetectEngineThreadCtx *det_ctx,
Packet *p, const Signature *s, const SigMatchCtx *ctx)
{
const DetectCsumData *cd = (const DetectCsumData *)ctx;
if (p->ip4h == NULL || p->icmpv4h == NULL || p->proto != IPPROTO_ICMP || PKT_IS_PSEUDOPKT(p))
return 0;
if (p->flags & PKT_IGNORE_CHECKSUM) {
return cd->valid;
}
if (p->level4_comp_csum == -1)
p->level4_comp_csum = ICMPV4CalculateChecksum((uint16_t *)p->icmpv4h,
SCNtohs(IPV4_GET_RAW_IPLEN(p->ip4h)) -
IPV4_GET_RAW_HLEN(p->ip4h) * 4);
if (p->level4_comp_csum == p->icmpv4h->checksum && cd->valid == 1)
return 1;
else if (p->level4_comp_csum != p->icmpv4h->checksum && cd->valid == 0)
return 1;
else
return 0;
}
/**
* \brief Creates a SigMatch for the icmpv4-csum keyword being sent as argument,
* and appends it to the Signature(s). Accepts 2 values for the
* keyword - "valid" and "invalid", both with and without quotes
*
* \param de_ctx Pointer to the detection engine context
* \param s Pointer to signature for the current Signature being parsed
* from the rules
* \param csum_str Pointer to the string holding the keyword value
*
* \retval 0 on success, -1 on failure
*/
static int DetectICMPV4CsumSetup(DetectEngineCtx *de_ctx, Signature *s, const char *csum_str)
{
DetectCsumData *cd = NULL;
SigMatch *sm = NULL;
//printf("DetectCsumSetup: \'%s\'\n", csum_str);
sm = SigMatchAlloc();
if (sm == NULL)
goto error;
sm->type = DETECT_ICMPV4_CSUM;
if ( (cd = SCMalloc(sizeof(DetectCsumData))) == NULL)
goto error;
memset(cd, 0, sizeof(DetectCsumData));
if (DetectCsumParseArg(csum_str, cd) == 0)
goto error;
sm->ctx = (SigMatchCtx *)cd;
SigMatchAppendSMToList(s, sm, DETECT_SM_LIST_MATCH);
return 0;
error:
if (cd != NULL) DetectICMPV4CsumFree(de_ctx, cd);
if (sm != NULL) SCFree(sm);
return -1;
}
static void DetectICMPV4CsumFree(DetectEngineCtx *de_ctx, void *ptr)
{
DetectCsumData *cd = (DetectCsumData *)ptr;
if (cd != NULL)
SCFree(cd);
return;
}
/**
* \brief Checks if the packet sent as the argument, has a valid or invalid
* icmpv6 checksum, based on whether icmpv6-csum option for this rule
* has been supplied with "valid" or "invalid" argument
*
* \param t Pointer to the tv for this detection module instance
* \param det_ctx Pointer to the detection engine thread context
* \param p Pointer to the Packet currently being matched
* \param s Pointer to the Signature, the packet is being currently
* matched with
* \param m Pointer to the keyword_structure(SigMatch) from the above
* Signature, the Packet is being currently matched with
*
* \retval 1 if the Packet contents match the keyword option; 0 otherwise
*/
static int DetectICMPV6CsumMatch(DetectEngineThreadCtx *det_ctx,
Packet *p, const Signature *s, const SigMatchCtx *ctx)
{
const DetectCsumData *cd = (const DetectCsumData *)ctx;
if (p->ip6h == NULL || p->icmpv6h == NULL || p->proto != IPPROTO_ICMPV6 || PKT_IS_PSEUDOPKT(p) ||
(GET_PKT_LEN(p) - ((uint8_t *)p->icmpv6h - GET_PKT_DATA(p))) <= 0) {
return 0;
}
if (p->flags & PKT_IGNORE_CHECKSUM) {
return cd->valid;
}
if (p->level4_comp_csum == -1) {
uint16_t len = IPV6_GET_RAW_PLEN(p->ip6h) -
((uint8_t *)p->icmpv6h - (uint8_t *)p->ip6h - IPV6_HEADER_LEN);
p->level4_comp_csum = ICMPV6CalculateChecksum(p->ip6h->s_ip6_addrs,
(uint16_t *)p->icmpv6h,
len);
}
if (p->level4_comp_csum == p->icmpv6h->csum && cd->valid == 1)
return 1;
else if (p->level4_comp_csum != p->icmpv6h->csum && cd->valid == 0)
return 1;
else
return 0;
}
/**
* \brief Creates a SigMatch for the icmpv6-csum keyword being sent as argument,
* and appends it to the Signature(s). Accepts 2 values for the
* keyword - "valid" and "invalid", both with and without quotes
*
* \param de_ctx Pointer to the detection engine context
* \param s Pointer to signature for the current Signature being parsed
* from the rules
* \param csum_str Pointer to the string holding the keyword value
*
* \retval 0 on success, -1 on failure
*/
static int DetectICMPV6CsumSetup(DetectEngineCtx *de_ctx, Signature *s, const char *csum_str)
{
DetectCsumData *cd = NULL;
SigMatch *sm = NULL;
sm = SigMatchAlloc();
if (sm == NULL)
goto error;
sm->type = DETECT_ICMPV6_CSUM;
if ( (cd = SCMalloc(sizeof(DetectCsumData))) == NULL)
goto error;
memset(cd, 0, sizeof(DetectCsumData));
if (DetectCsumParseArg(csum_str, cd) == 0)
goto error;
sm->ctx = (SigMatchCtx *)cd;
SigMatchAppendSMToList(s, sm, DETECT_SM_LIST_MATCH);
return 0;
error:
if (cd != NULL) DetectICMPV6CsumFree(de_ctx, cd);
if (sm != NULL) SCFree(sm);
return -1;
}
static void DetectICMPV6CsumFree(DetectEngineCtx *de_ctx, void *ptr)
{
DetectCsumData *cd = (DetectCsumData *)ptr;
if (cd != NULL)
SCFree(cd);
return;
}
/* ---------------------------------- Unit Tests --------------------------- */
#ifdef UNITTESTS
#include "detect-engine.h"
#define mystr(s) #s
#define TEST1(kwstr) {\
DetectEngineCtx *de_ctx = DetectEngineCtxInit();\
FAIL_IF_NULL(de_ctx);\
de_ctx->flags = DE_QUIET;\
\
Signature *s = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any ("mystr(kwstr)"-csum:valid; sid:1;)");\
FAIL_IF_NULL(s);\
s = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any ("mystr(kwstr)"-csum:invalid; sid:2;)");\
FAIL_IF_NULL(s);\
s = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any ("mystr(kwstr)"-csum:vaLid; sid:3;)");\
FAIL_IF_NULL(s);\
s = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any ("mystr(kwstr)"-csum:VALID; sid:4;)");\
FAIL_IF_NULL(s);\
s = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any ("mystr(kwstr)"-csum:iNvaLid; sid:5;)");\
FAIL_IF_NULL(s);\
DetectEngineCtxFree(de_ctx);\
}
static int DetectCsumValidArgsTestParse01(void)
{
TEST1(ipv4);
TEST1(tcpv4);
TEST1(tcpv6);
TEST1(udpv4);
TEST1(udpv6);
TEST1(icmpv4);
TEST1(icmpv6);
PASS;
}
#undef TEST1
#define TEST2(kwstr) { \
DetectEngineCtx *de_ctx = DetectEngineCtxInit();\
FAIL_IF_NULL(de_ctx);\
Signature *s = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any ("mystr(kwstr)"-csum:vaid; sid:1;)");\
FAIL_IF(s);\
s = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any ("mystr(kwstr)"-csum:invaalid; sid:2;)");\
FAIL_IF(s);\
s = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any ("mystr(kwstr)"-csum:vaLiid; sid:3;)");\
FAIL_IF(s);\
s = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any ("mystr(kwstr)"-csum:VALieD; sid:4;)");\
FAIL_IF(s);\
s = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any ("mystr(kwstr)"-csum:iNvamid; sid:5;)");\
FAIL_IF(s);\
DetectEngineCtxFree(de_ctx);\
}
static int DetectCsumInvalidArgsTestParse02(void)
{
TEST2(ipv4);
TEST2(tcpv4);
TEST2(tcpv6);
TEST2(udpv4);
TEST2(udpv6);
TEST2(icmpv4);
TEST2(icmpv6);
PASS;
}
#undef TEST2
#define TEST3(kwstr, kwtype) { \
DetectEngineCtx *de_ctx = DetectEngineCtxInit();\
FAIL_IF_NULL(de_ctx);\
Signature *s = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any ("mystr(kwstr)"-csum:valid; sid:1;)");\
FAIL_IF_NULL(s);\
SigMatch *sm = DetectGetLastSMFromLists(s, (kwtype), -1);\
FAIL_IF_NULL(sm);\
FAIL_IF_NULL(sm->ctx);\
FAIL_IF_NOT(((DetectCsumData *)sm->ctx)->valid == 1);\
s = DetectEngineAppendSig(de_ctx, "alert ip any any -> any any ("mystr(kwstr)"-csum:INVALID; sid:2;)");\
FAIL_IF_NULL(s);\
sm = DetectGetLastSMFromLists(s, (kwtype), -1);\
FAIL_IF_NULL(sm);\
FAIL_IF_NULL(sm->ctx);\
FAIL_IF_NOT(((DetectCsumData *)sm->ctx)->valid == 0);\
DetectEngineCtxFree(de_ctx);\
}
static int DetectCsumValidArgsTestParse03(void)
{
TEST3(ipv4, DETECT_IPV4_CSUM);
TEST3(tcpv4, DETECT_TCPV4_CSUM);
TEST3(tcpv6, DETECT_TCPV6_CSUM);
TEST3(udpv4, DETECT_UDPV4_CSUM);
TEST3(udpv6, DETECT_UDPV6_CSUM);
TEST3(icmpv4, DETECT_ICMPV4_CSUM);
TEST3(icmpv6, DETECT_ICMPV6_CSUM);
PASS;
}
#undef TEST3
#undef mystr
#include "detect-engine.h"
#include "stream-tcp.h"
static int DetectCsumICMPV6Test01(void)
{
DetectEngineCtx *de_ctx = NULL;
Signature *s = NULL;
ThreadVars tv;
DetectEngineThreadCtx *det_ctx = NULL;
DecodeThreadVars dtv;
Packet *p = PacketGetFromAlloc();
FAIL_IF_NULL(p);
uint8_t pkt[] = {
0x00, 0x30, 0x18, 0xa8, 0x7c, 0x23, 0x2c, 0x41,
0x38, 0xa7, 0xea, 0xeb, 0x86, 0xdd, 0x60, 0x00,
0x00, 0x00, 0x00, 0x40, 0x3c, 0x40, 0xad, 0xa1,
0x09, 0x80, 0x00, 0x01, 0xd6, 0xf3, 0x20, 0x01,
0xf4, 0xbe, 0xea, 0x3c, 0x00, 0x01, 0x00, 0x00,
0x00, 0x00, 0x32, 0xb2, 0x00, 0x01, 0x32, 0xb2,
0x09, 0x80, 0x20, 0x01, 0x00, 0x00, 0x3c, 0x00,
0x01, 0x04, 0x00, 0x00, 0x00, 0x00, 0x3c, 0x00,
0x01, 0x04, 0x00, 0x00, 0x00, 0x00, 0x2c, 0x00,
0x01, 0x04, 0x00, 0x00, 0x00, 0x00, 0x2c, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x3c, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x2c, 0x00,
0x01, 0x04, 0x00, 0x00, 0x00, 0x00, 0x3a, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80, 0x00,
0x63, 0xc2, 0x00, 0x00, 0x00, 0x00 };
PacketCopyData(p, pkt, sizeof(pkt));
memset(&tv, 0, sizeof(tv));
memset(&dtv, 0, sizeof(dtv));
StreamTcpInitConfig(true);
FlowInitConfig(FLOW_QUIET);
de_ctx = DetectEngineCtxInit();
FAIL_IF_NULL(de_ctx);
de_ctx->mpm_matcher = mpm_default_matcher;
de_ctx->flags |= DE_QUIET;
s = de_ctx->sig_list = SigInit(de_ctx, "alert ip any any -> any any "
"(icmpv6-csum:valid; sid:1;)");
FAIL_IF_NULL(s);
SigGroupBuild(de_ctx);
DecodeEthernet(&tv, &dtv, p, GET_PKT_DATA(p), GET_PKT_LEN(p));
DetectEngineThreadCtxInit(&tv, (void *)de_ctx, (void *)&det_ctx);
SigMatchSignatures(&tv, de_ctx, det_ctx, p);
FAIL_IF(!PacketAlertCheck(p, 1));
DetectEngineThreadCtxDeinit(&tv, det_ctx);
DetectEngineCtxFree(de_ctx);
StreamTcpFreeConfig(true);
PACKET_RECYCLE(p);
FlowShutdown();
SCFree(p);
PASS;
}
static void DetectCsumRegisterTests(void)
{
UtRegisterTest("DetectCsumValidArgsTestParse01",
DetectCsumValidArgsTestParse01);
UtRegisterTest("DetectCsumInvalidArgsTestParse02",
DetectCsumInvalidArgsTestParse02);
UtRegisterTest("DetectCsumValidArgsTestParse03",
DetectCsumValidArgsTestParse03);
UtRegisterTest("DetectCsumICMPV6Test01",
DetectCsumICMPV6Test01);
}
#endif /* UNITTESTS */