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suricata/src/detect.c

2344 lines
94 KiB
C

/* Copyright (C) 2007-2025 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>
*
* Basic detection engine
*/
#include "suricata-common.h"
#include "suricata.h"
#include "decode.h"
#include "packet.h"
#include "flow.h"
#include "stream-tcp.h"
#include "app-layer.h"
#include "app-layer-parser.h"
#include "app-layer-frames.h"
#include "detect.h"
#include "detect-dsize.h"
#include "detect-engine.h"
#include "detect-engine-build.h"
#include "detect-engine-frame.h"
#include "detect-engine-profile.h"
#include "detect-engine-alert.h"
#include "detect-engine-siggroup.h"
#include "detect-engine-address.h"
#include "detect-engine-proto.h"
#include "detect-engine-port.h"
#include "detect-engine-mpm.h"
#include "detect-engine-iponly.h"
#include "detect-engine-threshold.h"
#include "detect-engine-prefilter.h"
#include "detect-engine-state.h"
#include "detect-engine-analyzer.h"
#include "detect-engine-payload.h"
#include "detect-engine-event.h"
#include "detect-filestore.h"
#include "detect-flowvar.h"
#include "detect-replace.h"
#include "util-validate.h"
#include "util-detect.h"
#include "util-profiling.h"
#include "action-globals.h"
typedef struct DetectRunScratchpad {
const AppProto alproto;
const uint8_t flow_flags; /* flow/state flags: STREAM_* */
const bool app_decoder_events;
const SigGroupHead *sgh;
} DetectRunScratchpad;
/* prototypes */
static DetectRunScratchpad DetectRunSetup(const DetectEngineCtx *de_ctx,
DetectEngineThreadCtx *det_ctx, Packet * const p, Flow * const pflow);
static void DetectRunInspectIPOnly(ThreadVars *tv, const DetectEngineCtx *de_ctx,
DetectEngineThreadCtx *det_ctx, Flow * const pflow, Packet * const p);
static inline void DetectRunGetRuleGroup(const DetectEngineCtx *de_ctx,
Packet * const p, Flow * const pflow, DetectRunScratchpad *scratch);
static inline void DetectRunPrefilterPkt(ThreadVars *tv,
DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx, Packet *p,
DetectRunScratchpad *scratch);
static inline uint8_t DetectRulePacketRules(ThreadVars *const tv, DetectEngineCtx *const de_ctx,
DetectEngineThreadCtx *const det_ctx, Packet *const p, Flow *const pflow,
const DetectRunScratchpad *scratch);
static void DetectRunTx(ThreadVars *tv, DetectEngineCtx *de_ctx,
DetectEngineThreadCtx *det_ctx, Packet *p,
Flow *f, DetectRunScratchpad *scratch);
static void DetectRunFrames(ThreadVars *tv, DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx,
Packet *p, Flow *f, DetectRunScratchpad *scratch);
static inline void DetectRunPostRules(ThreadVars *tv, DetectEngineCtx *de_ctx,
DetectEngineThreadCtx *det_ctx, Packet * const p, Flow * const pflow,
DetectRunScratchpad *scratch);
static void DetectRunCleanup(DetectEngineThreadCtx *det_ctx,
Packet *p, Flow * const pflow);
static inline void DetectRunAppendDefaultAccept(DetectEngineThreadCtx *det_ctx, Packet *p);
/** \internal
*/
static void DetectRun(ThreadVars *th_v,
DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx,
Packet *p)
{
SCEnter();
SCLogDebug("p->pcap_cnt %" PRIu64 " direction %s pkt_src %s", p->pcap_cnt,
p->flow ? (FlowGetPacketDirection(p->flow, p) == TOSERVER ? "toserver" : "toclient")
: "noflow",
PktSrcToString(p->pkt_src));
/* Load the Packet's flow early, even though it might not be needed.
* Mark as a constant pointer, although the flow itself can change. */
Flow * const pflow = p->flow;
DetectRunScratchpad scratch = DetectRunSetup(de_ctx, det_ctx, p, pflow);
/* run the IPonly engine */
DetectRunInspectIPOnly(th_v, de_ctx, det_ctx, pflow, p);
/* get our rule group */
DetectRunGetRuleGroup(de_ctx, p, pflow, &scratch);
/* if we didn't get a sig group head, we
* have nothing to do.... */
if (scratch.sgh == NULL) {
SCLogDebug("no sgh for this packet, nothing to match against");
goto end;
}
/* run the prefilters for packets */
DetectRunPrefilterPkt(th_v, de_ctx, det_ctx, p, &scratch);
PACKET_PROFILING_DETECT_START(p, PROF_DETECT_RULES);
/* inspect the rules against the packet */
const uint8_t pkt_policy = DetectRulePacketRules(th_v, de_ctx, det_ctx, p, pflow, &scratch);
PACKET_PROFILING_DETECT_END(p, PROF_DETECT_RULES);
/* Only FW rules will already have set the action, IDS rules go through PacketAlertFinalize
*
* If rules told us to drop or accept:packet/accept:flow, we skip app_filter and app_td.
*
* accept:hook won't have set the pkt_policy, so we simply continue.
*
* TODO what about app state progression, cleanup and such? */
if (pkt_policy & (ACTION_DROP | ACTION_ACCEPT)) {
goto end;
}
/* run tx/state inspection. Don't call for ICMP error msgs. */
if (pflow && pflow->alstate && likely(pflow->proto == p->proto)) {
if (p->proto == IPPROTO_TCP) {
if ((p->flags & PKT_STREAM_EST) == 0) {
SCLogDebug("packet %" PRIu64 ": skip tcp non-established", p->pcap_cnt);
DetectRunAppendDefaultAccept(det_ctx, p);
goto end;
}
const TcpSession *ssn = p->flow->protoctx;
bool setting_nopayload = p->flow->alparser &&
AppLayerParserStateIssetFlag(
p->flow->alparser, APP_LAYER_PARSER_NO_INSPECTION) &&
!(p->flags & PKT_NOPAYLOAD_INSPECTION);
// we may be right after disabling app-layer (ssh)
if (ssn &&
((ssn->flags & STREAMTCP_FLAG_APP_LAYER_DISABLED) == 0 || setting_nopayload)) {
// PACKET_PROFILING_DETECT_START(p, PROF_DETECT_TX);
DetectRunFrames(th_v, de_ctx, det_ctx, p, pflow, &scratch);
// PACKET_PROFILING_DETECT_END(p, PROF_DETECT_TX);
}
// no update to transactions
if (!PKT_IS_PSEUDOPKT(p) && p->app_update_direction == 0 &&
((PKT_IS_TOSERVER(p) && (p->flow->flags & FLOW_TS_APP_UPDATED) == 0) ||
(PKT_IS_TOCLIENT(p) && (p->flow->flags & FLOW_TC_APP_UPDATED) == 0))) {
SCLogDebug("packet %" PRIu64 ": no app-layer update", p->pcap_cnt);
DetectRunAppendDefaultAccept(det_ctx, p);
goto end;
}
} else if (p->proto == IPPROTO_UDP) {
DetectRunFrames(th_v, de_ctx, det_ctx, p, pflow, &scratch);
}
PACKET_PROFILING_DETECT_START(p, PROF_DETECT_TX);
DetectRunTx(th_v, de_ctx, det_ctx, p, pflow, &scratch);
PACKET_PROFILING_DETECT_END(p, PROF_DETECT_TX);
/* see if we need to increment the inspect_id and reset the de_state */
PACKET_PROFILING_DETECT_START(p, PROF_DETECT_TX_UPDATE);
AppLayerParserSetTransactionInspectId(
pflow, pflow->alparser, pflow->alstate, scratch.flow_flags, (scratch.sgh == NULL));
PACKET_PROFILING_DETECT_END(p, PROF_DETECT_TX_UPDATE);
} else {
SCLogDebug("packet %" PRIu64 ": no flow / app-layer", p->pcap_cnt);
DetectRunAppendDefaultAccept(det_ctx, p);
}
end:
DetectRunPostRules(th_v, de_ctx, det_ctx, p, pflow, &scratch);
DetectRunCleanup(det_ctx, p, pflow);
SCReturn;
}
static void DetectRunPostMatch(ThreadVars *tv,
DetectEngineThreadCtx *det_ctx, Packet *p,
const Signature *s)
{
/* run the packet match functions */
const SigMatchData *smd = s->sm_arrays[DETECT_SM_LIST_POSTMATCH];
if (smd != NULL) {
KEYWORD_PROFILING_SET_LIST(det_ctx, DETECT_SM_LIST_POSTMATCH);
SCLogDebug("running match functions, sm %p", smd);
while (1) {
KEYWORD_PROFILING_START;
(void)sigmatch_table[smd->type].Match(det_ctx, p, s, smd->ctx);
KEYWORD_PROFILING_END(det_ctx, smd->type, 1);
if (smd->is_last)
break;
smd++;
}
}
}
/**
* \brief Get the SigGroupHead for a packet.
*
* \param de_ctx detection engine context
* \param p packet
*
* \retval sgh the SigGroupHead or NULL if non applies to the packet
*/
const SigGroupHead *SigMatchSignaturesGetSgh(const DetectEngineCtx *de_ctx,
const Packet *p)
{
SCEnter();
SigGroupHead *sgh = NULL;
/* if the packet proto is 0 (not set), we're inspecting it against
* the decoder events sgh we have. */
if (p->proto == 0 && p->events.cnt > 0) {
SCReturnPtr(de_ctx->decoder_event_sgh, "SigGroupHead");
} else if (p->proto == 0) {
if (!(PacketIsIPv4(p) || PacketIsIPv6(p))) {
/* not IP, so nothing to do */
SCReturnPtr(NULL, "SigGroupHead");
}
}
/* select the flow_gh */
const int dir = (p->flowflags & FLOW_PKT_TOCLIENT) == 0;
int proto = PacketGetIPProto(p);
if (proto == IPPROTO_TCP) {
DetectPort *list = de_ctx->flow_gh[dir].tcp;
SCLogDebug("tcp toserver %p, tcp toclient %p: going to use %p", de_ctx->flow_gh[1].tcp,
de_ctx->flow_gh[0].tcp, de_ctx->flow_gh[dir].tcp);
const uint16_t port = dir ? p->dp : p->sp;
SCLogDebug("tcp port %u -> %u:%u", port, p->sp, p->dp);
DetectPort *sghport = DetectPortLookupGroup(list, port);
if (sghport != NULL)
sgh = sghport->sh;
SCLogDebug("TCP list %p, port %u, direction %s, sghport %p, sgh %p", list, port,
dir ? "toserver" : "toclient", sghport, sgh);
} else if (proto == IPPROTO_UDP) {
DetectPort *list = de_ctx->flow_gh[dir].udp;
uint16_t port = dir ? p->dp : p->sp;
DetectPort *sghport = DetectPortLookupGroup(list, port);
if (sghport != NULL)
sgh = sghport->sh;
SCLogDebug("UDP list %p, port %u, direction %s, sghport %p, sgh %p", list, port,
dir ? "toserver" : "toclient", sghport, sgh);
} else {
sgh = de_ctx->flow_gh[dir].sgh[proto];
}
SCReturnPtr(sgh, "SigGroupHead");
}
static inline void DetectPrefilterCopyDeDup(DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx)
{
SigIntId *pf_ptr = det_ctx->pmq.rule_id_array;
uint32_t final_cnt = det_ctx->pmq.rule_id_array_cnt;
Signature **sig_array = de_ctx->sig_array;
Signature **match_array = det_ctx->match_array;
SigIntId previous_id = (SigIntId)-1;
while (final_cnt-- > 0) {
SigIntId id = *pf_ptr++;
Signature *s = sig_array[id];
/* As the prefilter list can contain duplicates, check for that here. */
if (likely(id != previous_id)) {
*match_array++ = s;
previous_id = id;
}
}
det_ctx->match_array_cnt = match_array - det_ctx->match_array;
DEBUG_VALIDATE_BUG_ON(det_ctx->pmq.rule_id_array_cnt < det_ctx->match_array_cnt);
PMQ_RESET(&det_ctx->pmq);
}
/** \internal
* \brief update flow's file tracking flags based on the detection engine
* A set of flags is prepared that is sent to the File API. The
File API may reject one or more based on the global force settings.
*/
static inline void
DetectPostInspectFileFlagsUpdate(Flow *f, const SigGroupHead *sgh, uint8_t direction)
{
uint16_t flow_file_flags = FLOWFILE_INIT;
if (sgh == NULL) {
SCLogDebug("requesting disabling all file features for flow");
flow_file_flags = FLOWFILE_NONE;
} else {
if (sgh->filestore_cnt == 0) {
SCLogDebug("requesting disabling filestore for flow");
flow_file_flags |= (FLOWFILE_NO_STORE_TS|FLOWFILE_NO_STORE_TC);
}
#ifdef HAVE_MAGIC
if (!(sgh->flags & SIG_GROUP_HEAD_HAVEFILEMAGIC)) {
SCLogDebug("requesting disabling magic for flow");
flow_file_flags |= (FLOWFILE_NO_MAGIC_TS|FLOWFILE_NO_MAGIC_TC);
}
#endif
if (!(sgh->flags & SIG_GROUP_HEAD_HAVEFILEMD5)) {
SCLogDebug("requesting disabling md5 for flow");
flow_file_flags |= (FLOWFILE_NO_MD5_TS|FLOWFILE_NO_MD5_TC);
}
if (!(sgh->flags & SIG_GROUP_HEAD_HAVEFILESHA1)) {
SCLogDebug("requesting disabling sha1 for flow");
flow_file_flags |= (FLOWFILE_NO_SHA1_TS|FLOWFILE_NO_SHA1_TC);
}
if (!(sgh->flags & SIG_GROUP_HEAD_HAVEFILESHA256)) {
SCLogDebug("requesting disabling sha256 for flow");
flow_file_flags |= (FLOWFILE_NO_SHA256_TS|FLOWFILE_NO_SHA256_TC);
}
if (!(sgh->flags & SIG_GROUP_HEAD_HAVEFILESIZE)) {
SCLogDebug("requesting disabling filesize for flow");
flow_file_flags |= (FLOWFILE_NO_SIZE_TS|FLOWFILE_NO_SIZE_TC);
}
}
if (flow_file_flags != 0) {
FileUpdateFlowFileFlags(f, flow_file_flags, direction);
}
}
static inline void
DetectRunPostGetFirstRuleGroup(const Packet *p, Flow *pflow, const SigGroupHead *sgh)
{
if ((p->flowflags & FLOW_PKT_TOSERVER) && !(pflow->flags & FLOW_SGH_TOSERVER)) {
/* first time we see this toserver sgh, store it */
pflow->sgh_toserver = sgh;
pflow->flags |= FLOW_SGH_TOSERVER;
if (p->proto == IPPROTO_TCP && (sgh == NULL || !(sgh->flags & SIG_GROUP_HEAD_HAVERAWSTREAM))) {
if (pflow->protoctx != NULL) {
TcpSession *ssn = pflow->protoctx;
SCLogDebug("STREAMTCP_STREAM_FLAG_DISABLE_RAW ssn.client");
ssn->client.flags |= STREAMTCP_STREAM_FLAG_DISABLE_RAW;
}
}
DetectPostInspectFileFlagsUpdate(pflow,
pflow->sgh_toserver, STREAM_TOSERVER);
} else if ((p->flowflags & FLOW_PKT_TOCLIENT) && !(pflow->flags & FLOW_SGH_TOCLIENT)) {
pflow->sgh_toclient = sgh;
pflow->flags |= FLOW_SGH_TOCLIENT;
if (p->proto == IPPROTO_TCP && (sgh == NULL || !(sgh->flags & SIG_GROUP_HEAD_HAVERAWSTREAM))) {
if (pflow->protoctx != NULL) {
TcpSession *ssn = pflow->protoctx;
SCLogDebug("STREAMTCP_STREAM_FLAG_DISABLE_RAW ssn.server");
ssn->server.flags |= STREAMTCP_STREAM_FLAG_DISABLE_RAW;
}
}
DetectPostInspectFileFlagsUpdate(pflow,
pflow->sgh_toclient, STREAM_TOCLIENT);
}
}
static inline void DetectRunGetRuleGroup(
const DetectEngineCtx *de_ctx,
Packet * const p, Flow * const pflow,
DetectRunScratchpad *scratch)
{
const SigGroupHead *sgh = NULL;
if (pflow) {
bool use_flow_sgh = false;
/* Get the stored sgh from the flow (if any). Make sure we're not using
* the sgh for icmp error packets part of the same stream. */
if (PacketGetIPProto(p) == pflow->proto) { /* filter out icmp */
PACKET_PROFILING_DETECT_START(p, PROF_DETECT_GETSGH);
if ((p->flowflags & FLOW_PKT_TOSERVER) && (pflow->flags & FLOW_SGH_TOSERVER)) {
sgh = pflow->sgh_toserver;
SCLogDebug("sgh = pflow->sgh_toserver; => %p", sgh);
use_flow_sgh = true;
} else if ((p->flowflags & FLOW_PKT_TOCLIENT) && (pflow->flags & FLOW_SGH_TOCLIENT)) {
sgh = pflow->sgh_toclient;
SCLogDebug("sgh = pflow->sgh_toclient; => %p", sgh);
use_flow_sgh = true;
}
PACKET_PROFILING_DETECT_END(p, PROF_DETECT_GETSGH);
}
if (!(use_flow_sgh)) {
PACKET_PROFILING_DETECT_START(p, PROF_DETECT_GETSGH);
sgh = SigMatchSignaturesGetSgh(de_ctx, p);
PACKET_PROFILING_DETECT_END(p, PROF_DETECT_GETSGH);
/* HACK: prevent the wrong sgh (or NULL) from being stored in the
* flow's sgh pointers */
if (PacketIsICMPv4(p) && ICMPV4_DEST_UNREACH_IS_VALID(p)) {
; /* no-op */
} else {
/* store the found sgh (or NULL) in the flow to save us
* from looking it up again for the next packet.
* Also run other tasks */
DetectRunPostGetFirstRuleGroup(p, pflow, sgh);
}
}
} else { /* p->flags & PKT_HAS_FLOW */
/* no flow */
PACKET_PROFILING_DETECT_START(p, PROF_DETECT_GETSGH);
sgh = SigMatchSignaturesGetSgh(de_ctx, p);
PACKET_PROFILING_DETECT_END(p, PROF_DETECT_GETSGH);
}
scratch->sgh = sgh;
}
static void DetectRunInspectIPOnly(ThreadVars *tv, const DetectEngineCtx *de_ctx,
DetectEngineThreadCtx *det_ctx,
Flow * const pflow, Packet * const p)
{
if (pflow) {
if (p->flowflags & (FLOW_PKT_TOSERVER_FIRST | FLOW_PKT_TOCLIENT_FIRST)) {
SCLogDebug("testing against \"ip-only\" signatures");
PACKET_PROFILING_DETECT_START(p, PROF_DETECT_IPONLY);
IPOnlyMatchPacket(tv, de_ctx, det_ctx, &de_ctx->io_ctx, p);
PACKET_PROFILING_DETECT_END(p, PROF_DETECT_IPONLY);
}
} else { /* p->flags & PKT_HAS_FLOW */
/* no flow */
/* Even without flow we should match the packet src/dst */
PACKET_PROFILING_DETECT_START(p, PROF_DETECT_IPONLY);
IPOnlyMatchPacket(tv, de_ctx, det_ctx, &de_ctx->io_ctx, p);
PACKET_PROFILING_DETECT_END(p, PROF_DETECT_IPONLY);
}
}
/** \internal
* \brief inspect the rule header: protocol, ports, etc
* \retval bool false if no match, true if match */
static inline bool DetectRunInspectRuleHeader(const Packet *p, const Flow *f, const Signature *s,
const uint32_t sflags, const uint8_t s_proto_flags)
{
/* check if this signature has a requirement for flowvars of some type
* and if so, if we actually have any in the flow. If not, the sig
* can't match and we skip it. */
if ((p->flags & PKT_HAS_FLOW) && (sflags & SIG_FLAG_REQUIRE_FLOWVAR)) {
DEBUG_VALIDATE_BUG_ON(f == NULL);
/* no flowvars? skip this sig */
const bool fv = f->flowvar != NULL;
if (!fv) {
SCLogDebug("skipping sig as the flow has no flowvars and sig "
"has SIG_FLAG_REQUIRE_FLOWVAR flag set.");
return false;
}
}
if ((s_proto_flags & DETECT_PROTO_IPV4) && !PacketIsIPv4(p)) {
SCLogDebug("ip version didn't match");
return false;
}
if ((s_proto_flags & DETECT_PROTO_IPV6) && !PacketIsIPv6(p)) {
SCLogDebug("ip version didn't match");
return false;
}
if (DetectProtoContainsProto(&s->proto, PacketGetIPProto(p)) == 0) {
SCLogDebug("proto didn't match");
return false;
}
/* check the source & dst port in the sig */
if (p->proto == IPPROTO_TCP || p->proto == IPPROTO_UDP || p->proto == IPPROTO_SCTP) {
if (!(sflags & SIG_FLAG_DP_ANY)) {
if (p->flags & PKT_IS_FRAGMENT)
return false;
const DetectPort *dport = DetectPortLookupGroup(s->dp, p->dp);
if (dport == NULL) {
SCLogDebug("dport didn't match.");
return false;
}
}
if (!(sflags & SIG_FLAG_SP_ANY)) {
if (p->flags & PKT_IS_FRAGMENT)
return false;
const DetectPort *sport = DetectPortLookupGroup(s->sp, p->sp);
if (sport == NULL) {
SCLogDebug("sport didn't match.");
return false;
}
}
} else if ((sflags & (SIG_FLAG_DP_ANY|SIG_FLAG_SP_ANY)) != (SIG_FLAG_DP_ANY|SIG_FLAG_SP_ANY)) {
SCLogDebug("port-less protocol and sig needs ports");
return false;
}
/* check the destination address */
if (!(sflags & SIG_FLAG_DST_ANY)) {
if (PacketIsIPv4(p)) {
if (DetectAddressMatchIPv4(s->addr_dst_match4, s->addr_dst_match4_cnt, &p->dst) == 0)
return false;
} else if (PacketIsIPv6(p)) {
if (DetectAddressMatchIPv6(s->addr_dst_match6, s->addr_dst_match6_cnt, &p->dst) == 0)
return false;
}
}
/* check the source address */
if (!(sflags & SIG_FLAG_SRC_ANY)) {
if (PacketIsIPv4(p)) {
if (DetectAddressMatchIPv4(s->addr_src_match4, s->addr_src_match4_cnt, &p->src) == 0)
return false;
} else if (PacketIsIPv6(p)) {
if (DetectAddressMatchIPv6(s->addr_src_match6, s->addr_src_match6_cnt, &p->src) == 0)
return false;
}
}
return true;
}
/** \internal
* \brief run packet/stream prefilter engines
*/
static inline void DetectRunPrefilterPkt(
ThreadVars *tv,
DetectEngineCtx *de_ctx,
DetectEngineThreadCtx *det_ctx,
Packet *p,
DetectRunScratchpad *scratch
)
{
/* create our prefilter mask */
PacketCreateMask(p, &p->sig_mask, scratch->alproto, scratch->app_decoder_events);
/* run the prefilter engines */
Prefilter(det_ctx, scratch->sgh, p, scratch->flow_flags, p->sig_mask);
/* create match list if we have non-pf and/or pf */
if (det_ctx->pmq.rule_id_array_cnt) {
#ifdef PROFILING
if (tv) {
StatsAddUI64(tv, det_ctx->counter_mpm_list, (uint64_t)det_ctx->pmq.rule_id_array_cnt);
}
#endif
PACKET_PROFILING_DETECT_START(p, PROF_DETECT_PF_SORT2);
DetectPrefilterCopyDeDup(de_ctx, det_ctx);
PACKET_PROFILING_DETECT_END(p, PROF_DETECT_PF_SORT2);
}
}
/** \internal
* \brief check if the tx whose id is given is the only one
* live transaction for the flow in the given direction
*
* \param f flow
* \param txid transaction id
* \param dir direction
*
* \retval bool true if we are sure this tx is the only one live in said direction
*/
static bool IsOnlyTxInDirection(Flow *f, uint64_t txid, uint8_t dir)
{
uint64_t tx_cnt = AppLayerParserGetTxCnt(f, f->alstate);
if (tx_cnt == txid + 1) {
// only live tx
return true;
}
if (tx_cnt == txid + 2) {
// 2 live txs, one after us
void *tx = AppLayerParserGetTx(f->proto, f->alproto, f->alstate, txid + 1);
if (tx) {
AppLayerTxData *txd = AppLayerParserGetTxData(f->proto, f->alproto, tx);
// test if the other tx is unidirectional in the other way
if ((dir == STREAM_TOSERVER && (txd->flags & APP_LAYER_TX_SKIP_INSPECT_TS)) ||
(dir == STREAM_TOCLIENT && (txd->flags & APP_LAYER_TX_SKIP_INSPECT_TC))) {
return true;
}
}
}
return false;
}
static int SortHelper(const void *a, const void *b)
{
const Signature *sa = *(const Signature **)a;
const Signature *sb = *(const Signature **)b;
if (sa->num == sb->num)
return 0;
return sa->num > sb->num ? 1 : -1;
}
static inline uint8_t DetectRulePacketRules(ThreadVars *const tv, DetectEngineCtx *const de_ctx,
DetectEngineThreadCtx *const det_ctx, Packet *const p, Flow *const pflow,
const DetectRunScratchpad *scratch)
{
uint8_t action = 0;
bool fw_verdict = false;
const bool have_fw_rules = (de_ctx->flags & DE_HAS_FIREWALL) != 0;
const Signature *next_s = NULL;
/* inspect the sigs against the packet */
/* Prefetch the next signature. */
SigIntId match_cnt = det_ctx->match_array_cnt;
#ifdef PROFILING
if (tv) {
StatsAddUI64(tv, det_ctx->counter_match_list,
(uint64_t)match_cnt);
}
#endif
Signature **match_array = det_ctx->match_array;
SGH_PROFILING_RECORD(det_ctx, scratch->sgh);
#ifdef PROFILING
if (match_cnt >= de_ctx->profile_match_logging_threshold)
RulesDumpMatchArray(det_ctx, scratch->sgh, p);
#endif
bool skip_fw = false;
uint32_t sflags, next_sflags = 0;
if (match_cnt) {
next_s = *match_array++;
next_sflags = next_s->flags;
}
while (match_cnt--) {
RULE_PROFILING_START(p);
bool break_out_of_packet_filter = false;
uint8_t alert_flags = 0;
#ifdef PROFILE_RULES
bool smatch = false; /* signature match */
#endif
const Signature *s = next_s;
sflags = next_sflags;
if (match_cnt) {
next_s = *match_array++;
next_sflags = next_s->flags;
}
const uint8_t s_proto_flags = s->proto.flags;
SCLogDebug("packet %" PRIu64 ": inspecting signature id %" PRIu32 "", p->pcap_cnt, s->id);
/* if we accept:hook'd the `packet_filter` hook, we skip the rest of the firewall rules. */
if (s->flags & SIG_FLAG_FIREWALL) {
if (skip_fw) {
SCLogDebug("skipping firewall rule %u", s->id);
goto next;
}
} else if (have_fw_rules) {
/* fw mode, we skip anything after the fw rules if:
* - flow pass is set
* - packet pass (e.g. exception policy) */
if (p->flags & PKT_NOPACKET_INSPECTION ||
(pflow != NULL && pflow->flags & (FLOW_ACTION_PASS))) {
SCLogDebug("skipping firewall rule %u", s->id);
break_out_of_packet_filter = true;
goto next;
}
}
if (s->app_inspect != NULL) {
goto next; // handle sig in DetectRunTx
}
if (s->frame_inspect != NULL) {
goto next; // handle sig in DetectRunFrame
}
/* skip pkt sigs for flow end packets */
if ((p->flags & PKT_PSEUDO_STREAM_END) != 0 && s->type == SIG_TYPE_PKT)
goto next;
/* don't run mask check for stateful rules.
* There we depend on prefilter */
if ((s->mask & p->sig_mask) != s->mask) {
SCLogDebug("mask mismatch %x & %x != %x", s->mask, p->sig_mask, s->mask);
goto next;
}
if (SigDsizePrefilter(p, s, sflags))
goto next;
/* if the sig has alproto and the session as well they should match */
if (likely(sflags & SIG_FLAG_APPLAYER)) {
if (s->alproto != ALPROTO_UNKNOWN && !AppProtoEquals(s->alproto, scratch->alproto)) {
SCLogDebug("alproto mismatch");
goto next;
}
}
if (!DetectRunInspectRuleHeader(p, pflow, s, sflags, s_proto_flags)) {
goto next;
}
if (!DetectEnginePktInspectionRun(tv, det_ctx, s, pflow, p, &alert_flags)) {
goto next;
}
#ifdef PROFILE_RULES
smatch = true;
#endif
DetectRunPostMatch(tv, det_ctx, p, s);
uint64_t txid = PACKET_ALERT_NOTX;
if (pflow && pflow->alstate) {
uint8_t dir = (p->flowflags & FLOW_PKT_TOCLIENT) ? STREAM_TOCLIENT : STREAM_TOSERVER;
txid = AppLayerParserGetTransactionInspectId(pflow->alparser, dir);
if ((s->alproto != ALPROTO_UNKNOWN && pflow->proto == IPPROTO_UDP) ||
(de_ctx->guess_applayer && IsOnlyTxInDirection(pflow, txid, dir))) {
// if there is a UDP specific app-layer signature,
// or only one live transaction
// try to use the good tx for the packet direction
void *tx_ptr =
AppLayerParserGetTx(pflow->proto, pflow->alproto, pflow->alstate, txid);
AppLayerTxData *txd =
tx_ptr ? AppLayerParserGetTxData(pflow->proto, pflow->alproto, tx_ptr)
: NULL;
if (txd && txd->guessed_applayer_logged < de_ctx->guess_applayer_log_limit) {
alert_flags |= PACKET_ALERT_FLAG_TX;
if (pflow->proto != IPPROTO_UDP) {
alert_flags |= PACKET_ALERT_FLAG_TX_GUESSED;
}
txd->guessed_applayer_logged++;
}
}
}
AlertQueueAppend(det_ctx, s, p, txid, alert_flags);
if (det_ctx->post_rule_work_queue.len > 0) {
/* run post match prefilter engines on work queue */
PrefilterPostRuleMatch(det_ctx, scratch->sgh, p, pflow);
if (det_ctx->pmq.rule_id_array_cnt > 0) {
/* undo "prefetch" */
if (next_s)
match_array--;
/* create temporary rule pointer array starting
* at where we are in the current match array */
const Signature *replace[de_ctx->sig_array_len]; // TODO heap?
SCLogDebug("sig_array_len %u det_ctx->pmq.rule_id_array_cnt %u",
de_ctx->sig_array_len, det_ctx->pmq.rule_id_array_cnt);
const Signature **r = replace;
for (uint32_t x = 0; x < match_cnt; x++) {
*r++ = match_array[x];
SCLogDebug("appended %u", match_array[x]->id);
}
/* append the prefilter results, then sort it */
for (uint32_t x = 0; x < det_ctx->pmq.rule_id_array_cnt; x++) {
SCLogDebug("adding iid %u", det_ctx->pmq.rule_id_array[x]);
Signature *ts = de_ctx->sig_array[det_ctx->pmq.rule_id_array[x]];
SCLogDebug("adding id %u", ts->id);
if (ts->app_inspect == NULL) {
*r++ = ts;
match_cnt++;
}
}
if (match_cnt > 1) {
qsort(replace, match_cnt, sizeof(Signature *), SortHelper);
}
/* rewrite match_array to include the new additions, and deduplicate
* while at it. */
Signature **m = match_array;
Signature *last_sig = NULL;
uint32_t skipped = 0;
for (uint32_t x = 0; x < match_cnt; x++) {
/* de-duplicate */
if (last_sig == *m) {
skipped++;
continue;
}
last_sig = *m;
*m++ = (Signature *)replace[x];
}
match_cnt -= skipped;
/* prefetch next */
next_s = *match_array++;
next_sflags = next_s->flags;
SCLogDebug("%u rules added", det_ctx->pmq.rule_id_array_cnt);
det_ctx->post_rule_work_queue.len = 0;
PMQ_RESET(&det_ctx->pmq);
}
}
/* firewall logic in the packet:filter table:
* 1. firewall rules preceed the packet:td rules in the list
* 2. if no rule issues an accept, we drop
* 3. drop is immediate
* 4. accept:
* - hook: skip rest of fw rules, inspect packet:td rules
* - packet: immediate accept, no packet:td or app:* inspect
* - flow: as packet, but applied to all future packets in the
* flow as well
*/
if (s->flags & SIG_FLAG_FIREWALL) {
if (s->action & (ACTION_ACCEPT)) {
fw_verdict = true;
enum ActionScope as = s->action_scope;
if (as == ACTION_SCOPE_HOOK) {
/* accept:hook: jump to first TD. Implemented as:
* skip until the first TD rule.
* Don't update action as we're just continuing to the next hook. */
skip_fw = true;
} else if (as == ACTION_SCOPE_PACKET) {
/* accept:packet: break loop, return accept */
action |= s->action;
break_out_of_packet_filter = true;
} else if (as == ACTION_SCOPE_FLOW) {
/* accept:flow: break loop, return accept */
action |= s->action;
break_out_of_packet_filter = true;
/* set immediately, as we're in hook "packet_filter" */
if (pflow) {
pflow->flags |= FLOW_ACTION_ACCEPT;
}
}
} else if (s->action & ACTION_DROP) {
/* apply a drop immediately here */
fw_verdict = true;
action |= s->action;
break_out_of_packet_filter = true;
}
}
next:
DetectVarProcessList(det_ctx, pflow, p);
DetectReplaceFree(det_ctx);
RULE_PROFILING_END(det_ctx, s, smatch, p);
/* fw accept:packet or accept:flow means we're done here */
if (break_out_of_packet_filter)
break;
continue;
}
/* if no rule told us to accept, and no rule explicitly dropped, we invoke the default drop
* policy
*/
if (have_fw_rules) {
if (!fw_verdict) {
DEBUG_VALIDATE_BUG_ON(action & ACTION_DROP);
PacketDrop(p, ACTION_DROP, PKT_DROP_REASON_DEFAULT_PACKET_POLICY);
action |= ACTION_DROP;
} else {
/* apply fw action */
p->action |= action;
}
}
return action;
}
static DetectRunScratchpad DetectRunSetup(
const DetectEngineCtx *de_ctx,
DetectEngineThreadCtx *det_ctx,
Packet * const p, Flow * const pflow)
{
AppProto alproto = ALPROTO_UNKNOWN;
uint8_t flow_flags = 0; /* flow/state flags */
bool app_decoder_events = false;
PACKET_PROFILING_DETECT_START(p, PROF_DETECT_SETUP);
#ifdef UNITTESTS
p->alerts.cnt = 0;
p->alerts.discarded = 0;
p->alerts.suppressed = 0;
#endif
det_ctx->filestore_cnt = 0;
det_ctx->base64_decoded_len = 0;
det_ctx->raw_stream_progress = 0;
det_ctx->match_array_cnt = 0;
det_ctx->alert_queue_size = 0;
p->alerts.drop.action = 0;
#ifdef DEBUG
if (p->flags & PKT_STREAM_ADD) {
det_ctx->pkt_stream_add_cnt++;
}
#endif
/* grab the protocol state we will detect on */
if (p->flags & PKT_HAS_FLOW) {
DEBUG_VALIDATE_BUG_ON(pflow == NULL);
if (p->flowflags & FLOW_PKT_TOSERVER) {
flow_flags = STREAM_TOSERVER;
SCLogDebug("flag STREAM_TOSERVER set");
} else if (p->flowflags & FLOW_PKT_TOCLIENT) {
flow_flags = STREAM_TOCLIENT;
SCLogDebug("flag STREAM_TOCLIENT set");
}
SCLogDebug("p->flowflags 0x%02x", p->flowflags);
if (p->flags & PKT_STREAM_EOF) {
flow_flags |= STREAM_EOF;
SCLogDebug("STREAM_EOF set");
}
/* store tenant_id in the flow so that we can use it
* for creating pseudo packets */
if (p->tenant_id > 0 && pflow->tenant_id == 0) {
pflow->tenant_id = p->tenant_id;
}
/* live ruleswap check for flow updates */
if (pflow->de_ctx_version == 0) {
/* first time this flow is inspected, set id */
pflow->de_ctx_version = de_ctx->version;
} else if (pflow->de_ctx_version != de_ctx->version) {
/* first time we inspect flow with this de_ctx, reset */
pflow->flags &= ~FLOW_SGH_TOSERVER;
pflow->flags &= ~FLOW_SGH_TOCLIENT;
pflow->sgh_toserver = NULL;
pflow->sgh_toclient = NULL;
pflow->de_ctx_version = de_ctx->version;
GenericVarFree(pflow->flowvar);
pflow->flowvar = NULL;
DetectEngineStateResetTxs(pflow);
}
/* Retrieve the app layer state and protocol and the tcp reassembled
* stream chunks. */
if ((p->proto == IPPROTO_TCP && (p->flags & PKT_STREAM_EST)) ||
(p->proto == IPPROTO_UDP) ||
(p->proto == IPPROTO_SCTP && (p->flowflags & FLOW_PKT_ESTABLISHED)))
{
/* update flow flags with knowledge on disruptions */
flow_flags = FlowGetDisruptionFlags(pflow, flow_flags);
alproto = FlowGetAppProtocol(pflow);
if (p->proto == IPPROTO_TCP && pflow->protoctx &&
StreamReassembleRawHasDataReady(pflow->protoctx, p)) {
p->flags |= PKT_DETECT_HAS_STREAMDATA;
}
SCLogDebug("alproto %u", alproto);
} else {
SCLogDebug("packet doesn't have established flag set (proto %d)", p->proto);
}
app_decoder_events = AppLayerParserHasDecoderEvents(pflow->alparser);
}
DetectRunScratchpad pad = { alproto, flow_flags, app_decoder_events, NULL };
PACKET_PROFILING_DETECT_END(p, PROF_DETECT_SETUP);
return pad;
}
static inline void DetectRunPostRules(
ThreadVars *tv,
DetectEngineCtx *de_ctx,
DetectEngineThreadCtx *det_ctx,
Packet * const p,
Flow * const pflow,
DetectRunScratchpad *scratch)
{
/* so now let's iterate the alerts and remove the ones after a pass rule
* matched (if any). This is done inside PacketAlertFinalize() */
/* PR: installed "tag" keywords are handled after the threshold inspection */
PACKET_PROFILING_DETECT_START(p, PROF_DETECT_ALERT);
PacketAlertFinalize(de_ctx, det_ctx, p);
if (p->alerts.cnt > 0) {
StatsAddUI64(tv, det_ctx->counter_alerts, (uint64_t)p->alerts.cnt);
}
if (p->alerts.discarded > 0) {
StatsAddUI64(tv, det_ctx->counter_alerts_overflow, (uint64_t)p->alerts.discarded);
}
if (p->alerts.suppressed > 0) {
StatsAddUI64(tv, det_ctx->counter_alerts_suppressed, (uint64_t)p->alerts.suppressed);
}
PACKET_PROFILING_DETECT_END(p, PROF_DETECT_ALERT);
/* firewall: "fail" closed if we don't have an ACCEPT. This can happen
* if there was no rule group. */
// TODO review packet src types here
if (de_ctx->flags & DE_HAS_FIREWALL && !(p->action & ACTION_ACCEPT) &&
p->pkt_src == PKT_SRC_WIRE) {
SCLogDebug("packet %" PRIu64 ": droppit as no ACCEPT set %02x (pkt %s)", p->pcap_cnt,
p->action, PktSrcToString(p->pkt_src));
PacketDrop(p, ACTION_DROP, PKT_DROP_REASON_DEFAULT_PACKET_POLICY);
}
}
static void DetectRunCleanup(DetectEngineThreadCtx *det_ctx,
Packet *p, Flow * const pflow)
{
PACKET_PROFILING_DETECT_START(p, PROF_DETECT_CLEANUP);
InspectionBufferClean(det_ctx);
if (pflow != NULL) {
/* update inspected tracker for raw reassembly */
if (p->proto == IPPROTO_TCP && pflow->protoctx != NULL &&
(p->flags & PKT_DETECT_HAS_STREAMDATA)) {
StreamReassembleRawUpdateProgress(pflow->protoctx, p,
det_ctx->raw_stream_progress);
}
}
PACKET_PROFILING_DETECT_END(p, PROF_DETECT_CLEANUP);
SCReturn;
}
void RuleMatchCandidateTxArrayInit(DetectEngineThreadCtx *det_ctx, uint32_t size)
{
DEBUG_VALIDATE_BUG_ON(det_ctx->tx_candidates);
det_ctx->tx_candidates = SCCalloc(size, sizeof(RuleMatchCandidateTx));
if (det_ctx->tx_candidates == NULL) {
FatalError("failed to allocate %" PRIu64 " bytes",
(uint64_t)(size * sizeof(RuleMatchCandidateTx)));
}
det_ctx->tx_candidates_size = size;
SCLogDebug("array initialized to %u elements (%"PRIu64" bytes)",
size, (uint64_t)(size * sizeof(RuleMatchCandidateTx)));
}
void RuleMatchCandidateTxArrayFree(DetectEngineThreadCtx *det_ctx)
{
SCFree(det_ctx->tx_candidates);
det_ctx->tx_candidates_size = 0;
}
/* if size >= cur_space */
static inline bool RuleMatchCandidateTxArrayHasSpace(const DetectEngineThreadCtx *det_ctx,
const uint32_t need)
{
if (det_ctx->tx_candidates_size >= need)
return 1;
return 0;
}
/* realloc */
static int RuleMatchCandidateTxArrayExpand(DetectEngineThreadCtx *det_ctx, const uint32_t needed)
{
const uint32_t old_size = det_ctx->tx_candidates_size;
uint32_t new_size = needed;
void *ptmp = SCRealloc(det_ctx->tx_candidates, (new_size * sizeof(RuleMatchCandidateTx)));
if (ptmp == NULL) {
FatalError("failed to expand to %" PRIu64 " bytes",
(uint64_t)(new_size * sizeof(RuleMatchCandidateTx)));
// TODO can this be handled more gracefully?
}
det_ctx->tx_candidates = ptmp;
det_ctx->tx_candidates_size = new_size;
SCLogDebug("array expanded from %u to %u elements (%"PRIu64" bytes -> %"PRIu64" bytes)",
old_size, new_size, (uint64_t)(old_size * sizeof(RuleMatchCandidateTx)),
(uint64_t)(new_size * sizeof(RuleMatchCandidateTx))); (void)old_size;
return 1;
}
/** \internal
* \brief sort helper for sorting match candidates by id: ascending
*
* The id field is set from Signature::num, so we sort the candidates to match the signature
* sort order (ascending), where candidates that have flags go first.
*/
static int
DetectRunTxSortHelper(const void *a, const void *b)
{
const RuleMatchCandidateTx *s0 = a;
const RuleMatchCandidateTx *s1 = b;
if (s1->id == s0->id) {
if (s1->flags && !s0->flags)
return 1;
else if (!s1->flags && s0->flags)
return -1;
return 0;
} else
return s0->id > s1->id ? 1 : -1;
}
#if 0
#define TRACE_SID_TXS(sid,txs,...) \
do { \
char _trace_buf[2048]; \
snprintf(_trace_buf, sizeof(_trace_buf), __VA_ARGS__); \
SCLogNotice("%p/%"PRIu64"/%u: %s", txs->tx_ptr, txs->tx_id, sid, _trace_buf); \
} while(0)
#else
#define TRACE_SID_TXS(sid,txs,...)
#endif
// Get inner transaction for engine
void *DetectGetInnerTx(void *tx_ptr, AppProto alproto, AppProto engine_alproto, uint8_t flow_flags)
{
if (unlikely(alproto == ALPROTO_DOH2)) {
if (engine_alproto == ALPROTO_DNS) {
// need to get the dns tx pointer
tx_ptr = SCDoH2GetDnsTx(tx_ptr, flow_flags);
} else if (engine_alproto != ALPROTO_HTTP2 && engine_alproto != ALPROTO_UNKNOWN) {
// incompatible engine->alproto with flow alproto
tx_ptr = NULL;
}
} else if (engine_alproto != alproto && engine_alproto != ALPROTO_UNKNOWN) {
// incompatible engine->alproto with flow alproto
tx_ptr = NULL;
}
return tx_ptr;
}
/** \internal
* \brief inspect a rule against a transaction
*
* Inspect a rule. New detection or continued stateful
* detection.
*
* \param stored_flags pointer to stored flags or NULL.
* If stored_flags is set it means we're continuing
* inspection from an earlier run.
*
* \retval bool true sig matched, false didn't match
*/
static bool DetectRunTxInspectRule(ThreadVars *tv,
DetectEngineCtx *de_ctx,
DetectEngineThreadCtx *det_ctx,
Packet *p,
Flow *f,
const uint8_t in_flow_flags, // direction, EOF, etc
void *alstate,
DetectTransaction *tx,
const Signature *s,
uint32_t *stored_flags,
RuleMatchCandidateTx *can,
DetectRunScratchpad *scratch)
{
const uint8_t flow_flags = in_flow_flags;
const int direction = (flow_flags & STREAM_TOSERVER) ? 0 : 1;
uint32_t inspect_flags = stored_flags ? *stored_flags : 0;
int total_matches = 0;
uint16_t file_no_match = 0;
bool retval = false;
bool mpm_before_progress = false; // is mpm engine before progress?
bool mpm_in_progress = false; // is mpm engine in a buffer we will revisit?
TRACE_SID_TXS(s->id, tx, "starting %s", direction ? "toclient" : "toserver");
/* for a new inspection we inspect pkt header and packet matches */
if (likely(stored_flags == NULL)) {
TRACE_SID_TXS(s->id, tx, "first inspect, run packet matches");
if (!DetectRunInspectRuleHeader(p, f, s, s->flags, s->proto.flags)) {
TRACE_SID_TXS(s->id, tx, "DetectRunInspectRuleHeader() no match");
return false;
}
if (!DetectEnginePktInspectionRun(tv, det_ctx, s, f, p, NULL)) {
TRACE_SID_TXS(s->id, tx, "DetectEnginePktInspectionRun no match");
return false;
}
/* stream mpm and negated mpm sigs can end up here with wrong proto */
if (!(AppProtoEquals(s->alproto, f->alproto) || s->alproto == ALPROTO_UNKNOWN)) {
TRACE_SID_TXS(s->id, tx, "alproto mismatch");
return false;
}
}
const DetectEngineAppInspectionEngine *engine = s->app_inspect;
do {
TRACE_SID_TXS(s->id, tx, "engine %p inspect_flags %x", engine, inspect_flags);
// also if it is not the same direction, but
// this is a transactional signature, and we are toclient
if (!(inspect_flags & BIT_U32(engine->id)) &&
(direction == engine->dir || ((s->flags & SIG_FLAG_TXBOTHDIR) && direction == 1))) {
void *tx_ptr = DetectGetInnerTx(tx->tx_ptr, f->alproto, engine->alproto, flow_flags);
if (tx_ptr == NULL) {
if (engine->alproto != ALPROTO_UNKNOWN) {
/* special case: file_data on 'alert tcp' will have engines
* in the list that are not for us. */
engine = engine->next;
continue;
} else {
tx_ptr = tx->tx_ptr;
}
}
/* engines are sorted per progress, except that the one with
* mpm/prefilter enabled is first */
if (tx->tx_progress < engine->progress) {
SCLogDebug("tx progress %d < engine progress %d",
tx->tx_progress, engine->progress);
break;
}
if (engine->mpm) {
if (tx->tx_progress > engine->progress) {
TRACE_SID_TXS(s->id, tx,
"engine->mpm: t->tx_progress %u > engine->progress %u, so set "
"mpm_before_progress",
tx->tx_progress, engine->progress);
mpm_before_progress = true;
} else if (tx->tx_progress == engine->progress) {
TRACE_SID_TXS(s->id, tx,
"engine->mpm: t->tx_progress %u == engine->progress %u, so set "
"mpm_in_progress",
tx->tx_progress, engine->progress);
mpm_in_progress = true;
}
}
uint8_t engine_flags = flow_flags;
if (direction != engine->dir) {
engine_flags = flow_flags ^ (STREAM_TOCLIENT | STREAM_TOSERVER);
}
/* run callback: but bypass stream callback if we can */
uint8_t match;
if (unlikely(engine->stream && can->stream_stored)) {
match = can->stream_result;
TRACE_SID_TXS(s->id, tx, "stream skipped, stored result %d used instead", match);
} else if (engine->v2.Callback == NULL) {
/* TODO is this the cleanest way to support a non-app sig on a app hook? */
if (tx->tx_progress > engine->progress) {
mpm_before_progress = true; // TODO needs a new name now
}
/* we don't have to store a "hook" match, also don't want to keep any state to make
* sure the hook gets invoked again until tx progress progresses. */
if (tx->tx_progress <= engine->progress)
return DETECT_ENGINE_INSPECT_SIG_MATCH;
/* if progress > engine progress, track state to avoid additional matches */
match = DETECT_ENGINE_INSPECT_SIG_MATCH;
} else {
KEYWORD_PROFILING_SET_LIST(det_ctx, engine->sm_list);
DEBUG_VALIDATE_BUG_ON(engine->v2.Callback == NULL);
match = engine->v2.Callback(
de_ctx, det_ctx, engine, s, f, engine_flags, alstate, tx_ptr, tx->tx_id);
TRACE_SID_TXS(s->id, tx, "engine %p match %d", engine, match);
if (engine->stream) {
can->stream_stored = true;
can->stream_result = match;
TRACE_SID_TXS(s->id, tx, "stream ran, store result %d for next tx (if any)", match);
}
}
if (match == DETECT_ENGINE_INSPECT_SIG_MATCH) {
inspect_flags |= BIT_U32(engine->id);
engine = engine->next;
total_matches++;
continue;
} else if (match == DETECT_ENGINE_INSPECT_SIG_MATCH_MORE_FILES) {
/* if the file engine matched, but indicated more
* files are still in progress, we don't set inspect
* flags as these would end inspection for this tx */
engine = engine->next;
total_matches++;
continue;
} else if (match == DETECT_ENGINE_INSPECT_SIG_CANT_MATCH) {
inspect_flags |= DE_STATE_FLAG_SIG_CANT_MATCH;
inspect_flags |= BIT_U32(engine->id);
} else if (match == DETECT_ENGINE_INSPECT_SIG_CANT_MATCH_FILES) {
inspect_flags |= DE_STATE_FLAG_SIG_CANT_MATCH;
inspect_flags |= BIT_U32(engine->id);
file_no_match = 1;
}
/* implied DETECT_ENGINE_INSPECT_SIG_NO_MATCH */
if (engine->mpm && mpm_before_progress) {
inspect_flags |= DE_STATE_FLAG_SIG_CANT_MATCH;
inspect_flags |= BIT_U32(engine->id);
}
break;
} else if (!(inspect_flags & BIT_U32(engine->id)) && s->flags & SIG_FLAG_TXBOTHDIR &&
direction != engine->dir) {
// for transactional rules, the engines on the opposite direction
// are ordered by progress on the different side
// so we have a two mixed-up lists, and we skip the elements
if (direction == 0 && engine->next == NULL) {
// do not match yet on request only
break;
}
engine = engine->next;
continue;
}
engine = engine->next;
} while (engine != NULL);
TRACE_SID_TXS(s->id, tx, "inspect_flags %x, total_matches %u, engine %p",
inspect_flags, total_matches, engine);
if (engine == NULL && total_matches) {
inspect_flags |= DE_STATE_FLAG_FULL_INSPECT;
TRACE_SID_TXS(s->id, tx, "MATCH");
retval = true;
}
if (stored_flags) {
*stored_flags = inspect_flags;
TRACE_SID_TXS(s->id, tx, "continue inspect flags %08x", inspect_flags);
} else {
// store... or? If tx is done we might not want to come back to this tx
// also... if mpmid tracking is enabled, we won't do a sig again for this tx...
TRACE_SID_TXS(s->id, tx, "start inspect flags %08x", inspect_flags);
if (inspect_flags & DE_STATE_FLAG_SIG_CANT_MATCH) {
if (file_no_match) {
/* if we have a mismatch on a file sig, we need to keep state.
* We may get another file on the same tx (for http and smtp
* at least), so for a new file we need to re-eval the sig.
* Thoughts / TODO:
* - not for some protos that have 1 file per tx (e.g. nfs)
* - maybe we only need this for file sigs that mix with
* other matches? E.g. 'POST + filename', is different than
* just 'filename'.
*/
DetectRunStoreStateTx(scratch->sgh, f, tx->tx_ptr, tx->tx_id, s,
inspect_flags, flow_flags, file_no_match);
}
} else if ((inspect_flags & DE_STATE_FLAG_FULL_INSPECT) && mpm_before_progress) {
TRACE_SID_TXS(s->id, tx, "no need to store match sig, "
"mpm won't trigger for it anymore");
if (inspect_flags & DE_STATE_FLAG_FILE_INSPECT) {
TRACE_SID_TXS(s->id, tx, "except that for new files, "
"we may have to revisit anyway");
DetectRunStoreStateTx(scratch->sgh, f, tx->tx_ptr, tx->tx_id, s,
inspect_flags, flow_flags, file_no_match);
}
} else if ((inspect_flags & DE_STATE_FLAG_FULL_INSPECT) == 0 && mpm_in_progress) {
TRACE_SID_TXS(s->id, tx, "no need to store no-match sig, "
"mpm will revisit it");
} else if (inspect_flags != 0 || file_no_match != 0) {
TRACE_SID_TXS(s->id, tx, "storing state: flags %08x", inspect_flags);
DetectRunStoreStateTx(scratch->sgh, f, tx->tx_ptr, tx->tx_id, s,
inspect_flags, flow_flags, file_no_match);
}
}
return retval;
}
#define NO_TX \
{ \
NULL, 0, NULL, NULL, 0, 0, 0, 0, \
}
/** \internal
* \brief get a DetectTransaction object
* \retval struct filled with relevant info or all nulls/0s
*/
static DetectTransaction GetDetectTx(const uint8_t ipproto, const AppProto alproto,
const uint64_t tx_id, void *tx_ptr, const int tx_end_state, const uint8_t flow_flags)
{
AppLayerTxData *txd = AppLayerParserGetTxData(ipproto, alproto, tx_ptr);
const int tx_progress = AppLayerParserGetStateProgress(ipproto, alproto, tx_ptr, flow_flags);
bool updated = (flow_flags & STREAM_TOSERVER) ? txd->updated_ts : txd->updated_tc;
if (!updated && tx_progress < tx_end_state && ((flow_flags & STREAM_EOF) == 0)) {
DetectTransaction no_tx = NO_TX;
return no_tx;
}
const uint8_t inspected_flag =
(flow_flags & STREAM_TOSERVER) ? APP_LAYER_TX_INSPECTED_TS : APP_LAYER_TX_INSPECTED_TC;
if (unlikely(txd->flags & inspected_flag)) {
SCLogDebug("%" PRIu64 " tx already fully inspected for %s. Flags %02x", tx_id,
flow_flags & STREAM_TOSERVER ? "toserver" : "toclient", txd->flags);
DetectTransaction no_tx = NO_TX;
return no_tx;
}
const uint8_t skip_flag = (flow_flags & STREAM_TOSERVER) ? APP_LAYER_TX_SKIP_INSPECT_TS
: APP_LAYER_TX_SKIP_INSPECT_TC;
if (unlikely(txd->flags & skip_flag)) {
SCLogDebug("%" PRIu64 " tx should not be inspected in direction %s. Flags %02x", tx_id,
flow_flags & STREAM_TOSERVER ? "toserver" : "toclient", txd->flags);
DetectTransaction no_tx = NO_TX;
return no_tx;
}
const uint8_t detect_progress =
(flow_flags & STREAM_TOSERVER) ? txd->detect_progress_ts : txd->detect_progress_tc;
const int dir_int = (flow_flags & STREAM_TOSERVER) ? 0 : 1;
DetectEngineState *tx_de_state = txd->de_state;
DetectEngineStateDirection *tx_dir_state =
tx_de_state ? &tx_de_state->dir_state[dir_int] : NULL;
DetectTransaction tx = {
.tx_ptr = tx_ptr,
.tx_id = tx_id,
.tx_data_ptr = (struct AppLayerTxData *)txd,
.de_state = tx_dir_state,
.detect_progress = detect_progress,
.detect_progress_orig = detect_progress,
.tx_progress = tx_progress,
.tx_end_state = tx_end_state,
};
return tx;
}
static inline void StoreDetectProgress(
DetectTransaction *tx, const uint8_t flow_flags, const uint8_t progress)
{
AppLayerTxData *txd = (AppLayerTxData *)tx->tx_data_ptr;
if (flow_flags & STREAM_TOSERVER) {
txd->detect_progress_ts = progress;
} else {
txd->detect_progress_tc = progress;
}
}
// Merge 'state' rules from the regular prefilter
// updates array_idx on the way
static inline void RuleMatchCandidateMergeStateRules(
DetectEngineThreadCtx *det_ctx, uint32_t *array_idx)
{
// Now, we will merge 2 sorted lists :
// the one in det_ctx->tx_candidates
// and the one in det_ctx->match_array
// For match_array, we take only the relevant elements where s->app_inspect != NULL
// Basically, we iterate at the same time over the 2 lists
// comparing and taking an element from either.
// Trick is to do so in place in det_ctx->tx_candidates,
// so as to minimize the number of moves in det_ctx->tx_candidates.
// For this, the algorithm traverses the lists in reverse order.
// Otherwise, if the first element of match_array was to be put before
// all tx_candidates, we would need to shift all tx_candidates
// Retain the number of elements sorted in tx_candidates before merge
uint32_t j = *array_idx;
// First loop only counting the number of elements to add
for (uint32_t i = 0; i < det_ctx->match_array_cnt; i++) {
const Signature *s = det_ctx->match_array[i];
if (s->app_inspect != NULL) {
(*array_idx)++;
}
}
// Future number of elements in tx_candidates after merge
uint32_t k = *array_idx;
if (k == j) {
// no new element from match_array to merge in tx_candidates
return;
}
// variable i is for all elements of match_array (even not relevant ones)
// variable j is for elements of tx_candidates before merge
// variable k is for elements of tx_candidates after merge
for (uint32_t i = det_ctx->match_array_cnt; i > 0;) {
const Signature *s = det_ctx->match_array[i - 1];
if (s->app_inspect == NULL) {
// no relevant element, get the next one from match_array
i--;
continue;
}
// we have one element from match_array to merge in tx_candidates
k--;
if (j > 0) {
// j > 0 means there is still at least one element in tx_candidates to merge
const RuleMatchCandidateTx *s0 = &det_ctx->tx_candidates[j - 1];
if (s->num <= s0->id) {
// get next element from previous tx_candidates
j--;
// take the element from tx_candidates before merge
det_ctx->tx_candidates[k].s = det_ctx->tx_candidates[j].s;
det_ctx->tx_candidates[k].id = det_ctx->tx_candidates[j].id;
det_ctx->tx_candidates[k].flags = det_ctx->tx_candidates[j].flags;
det_ctx->tx_candidates[k].stream_reset = det_ctx->tx_candidates[j].stream_reset;
continue;
}
} // otherwise
// get next element from match_array
i--;
// take the element from match_array
det_ctx->tx_candidates[k].s = s;
det_ctx->tx_candidates[k].id = s->num;
det_ctx->tx_candidates[k].flags = NULL;
det_ctx->tx_candidates[k].stream_reset = 0;
}
// Even if k > 0 or j > 0, the loop is over. (Note that j == k now)
// The remaining elements in tx_candidates up to k were already sorted
// and come before any other element later in the list
}
/**
* \internal
* \brief Check and update firewall rules state.
*
* \param skip_fw_hook bool to indicate firewall rules skips
* For state `skip_before_progress` should be skipped.
*
* \param skip_before_progress progress value to skip rules before.
* Only used if `skip_fw_hook` is set.
*
* \param last_for_progress[out] set to true if this is the last rule for a progress value
*
* \param fw_next_progress_missing[out] set to true if the next fw rule does not target the next
* progress value, or there is no fw rule for that value.
*
* \retval 0 no action needed
* \retval 1 rest of rules shouldn't inspected
* \retval -1 skip this rule
*/
static int DetectRunTxCheckFirewallPolicy(DetectEngineThreadCtx *det_ctx, Packet *p, Flow *f,
DetectTransaction *tx, const Signature *s, const uint32_t can_idx, const uint32_t can_size,
bool *skip_fw_hook, const uint8_t skip_before_progress, bool *last_for_progress,
bool *fw_next_progress_missing)
{
if (s->flags & SIG_FLAG_FIREWALL) {
/* check if the next sig is on the same progress hook. If not, we need to apply our
* default policy in case the current sig doesn't apply one. If the next sig has a
* progress beyond our progress + 1, it means the next progress has no rules and needs
* the default policy applied. But only after we evaluate the current rule first, as
* that may override it.
* TODO should we do this after dedup below? */
if (can_idx + 1 < can_size) {
const Signature *next_s = det_ctx->tx_candidates[can_idx + 1].s;
SCLogDebug(
"peek: peeking at sid %u / progress %u", next_s->id, next_s->app_progress_hook);
if (next_s->flags & SIG_FLAG_FIREWALL) {
if (s->app_progress_hook != next_s->app_progress_hook) {
SCLogDebug("peek: next sid progress %u != current progress %u, so current "
"is last for progress",
next_s->app_progress_hook, s->app_progress_hook);
*last_for_progress = true;
if (next_s->app_progress_hook - s->app_progress_hook > 1) {
SCLogDebug("peek: missing progress, so we'll drop that unless we get a "
"sweeping accept first");
*fw_next_progress_missing = true;
}
}
} else {
SCLogDebug("peek: next sid not a fw rule, so current is last for progress");
*last_for_progress = true;
}
} else {
SCLogDebug("peek: no peek beyond last rule");
if (s->app_progress_hook < tx->tx_progress) {
SCLogDebug("peek: there are no rules to allow the state after this rule");
*fw_next_progress_missing = true;
}
}
if ((*skip_fw_hook) == true) {
if (s->app_progress_hook <= skip_before_progress) {
return -1;
}
*skip_fw_hook = false;
}
} else {
/* fw mode, we skip anything after the fw rules if:
* - flow pass is set
* - packet pass (e.g. exception policy) */
if (p->flags & PKT_NOPACKET_INSPECTION || (f->flags & (FLOW_ACTION_PASS))) {
SCLogDebug("skipping firewall rule %u", s->id);
return 1;
}
}
return 0;
}
// TODO move into det_ctx?
thread_local Signature default_accept;
static inline void DetectRunAppendDefaultAccept(DetectEngineThreadCtx *det_ctx, Packet *p)
{
if (det_ctx->de_ctx->flags & DE_HAS_FIREWALL) {
memset(&default_accept, 0, sizeof(default_accept));
default_accept.action = ACTION_ACCEPT;
default_accept.action_scope = ACTION_SCOPE_PACKET;
default_accept.num = UINT32_MAX;
default_accept.type = SIG_TYPE_PKT;
default_accept.flags = SIG_FLAG_FIREWALL;
AlertQueueAppend(det_ctx, &default_accept, p, 0, PACKET_ALERT_FLAG_APPLY_ACTION_TO_PACKET);
}
}
/** \internal
* \brief see if the accept rule needs to apply to the packet
*/
static inline bool ApplyAcceptToPacket(
const uint64_t total_txs, const DetectTransaction *tx, const Signature *s)
{
if ((s->flags & SIG_FLAG_FIREWALL) == 0) {
return false;
}
if ((s->action & ACTION_ACCEPT) == 0) {
return false;
}
/* for accept:tx we need:
* - packet will only be accepted if this is set on the last tx
*/
if (s->action_scope == ACTION_SCOPE_TX) {
if (total_txs == tx->tx_id + 1) {
return true;
}
}
/* for accept:hook we need a bit more checking:
* - packet will only be accepted if this is set on the last tx
* - the hook accepted should be the last progress available. */
if (s->action_scope == ACTION_SCOPE_HOOK) {
if ((total_txs == tx->tx_id + 1) && /* last tx */
(s->app_progress_hook == tx->tx_progress)) {
return true;
}
}
return false;
}
/** \internal
* \retval bool true: break_out_of_app_filter, false: don't break out */
static bool ApplyAccept(Packet *p, const uint8_t flow_flags, const Signature *s,
DetectTransaction *tx, const int tx_end_state, const bool fw_next_progress_missing,
bool *tx_fw_verdict, bool *skip_fw_hook, uint8_t *skip_before_progress)
{
*tx_fw_verdict = true;
const enum ActionScope as = s->action_scope;
/* accept:hook: jump to first rule of next state.
* Implemented as skip until the first rule of next state. */
if (as == ACTION_SCOPE_HOOK) {
*skip_fw_hook = true;
*skip_before_progress = s->app_progress_hook;
/* if there is no fw rule for the next progress value,
* we invoke the default drop policy. */
if (fw_next_progress_missing) {
SCLogDebug("%" PRIu64 ": %s default drop for progress", p->pcap_cnt,
flow_flags & STREAM_TOSERVER ? "toserver" : "toclient");
PacketDrop(p, ACTION_DROP, PKT_DROP_REASON_DEFAULT_APP_POLICY);
p->flow->flags |= FLOW_ACTION_DROP;
return true;
}
return false;
} else if (as == ACTION_SCOPE_TX) {
tx->tx_data_ptr->flags |= APP_LAYER_TX_ACCEPT;
*skip_fw_hook = true;
*skip_before_progress = (uint8_t)tx_end_state + 1; // skip all hooks
SCLogDebug(
"accept:tx applied, skip_fw_hook, skip_before_progress %u", *skip_before_progress);
return false;
} else if (as == ACTION_SCOPE_PACKET) {
return true;
} else if (as == ACTION_SCOPE_FLOW) {
return true;
}
return false;
}
static void DetectRunTx(ThreadVars *tv,
DetectEngineCtx *de_ctx,
DetectEngineThreadCtx *det_ctx,
Packet *p,
Flow *f,
DetectRunScratchpad *scratch)
{
const uint8_t flow_flags = scratch->flow_flags;
const SigGroupHead * const sgh = scratch->sgh;
void * const alstate = f->alstate;
const uint8_t ipproto = f->proto;
const AppProto alproto = f->alproto;
const uint64_t total_txs = AppLayerParserGetTxCnt(f, alstate);
uint64_t tx_id_min = AppLayerParserGetTransactionInspectId(f->alparser, flow_flags);
const int tx_end_state = AppLayerParserGetStateProgressCompletionStatus(alproto, flow_flags);
AppLayerGetTxIteratorFunc IterFunc = AppLayerGetTxIterator(ipproto, alproto);
AppLayerGetTxIterState state = { 0 };
uint32_t fw_verdicted = 0;
uint32_t tx_inspected = 0;
const bool have_fw_rules = (de_ctx->flags & DE_HAS_FIREWALL) != 0;
SCLogDebug("packet %" PRIu64, p->pcap_cnt);
while (1) {
AppLayerGetTxIterTuple ires = IterFunc(ipproto, alproto, alstate, tx_id_min, total_txs, &state);
if (ires.tx_ptr == NULL)
break;
DetectTransaction tx =
GetDetectTx(ipproto, alproto, ires.tx_id, ires.tx_ptr, tx_end_state, flow_flags);
if (tx.tx_ptr == NULL) {
SCLogDebug("%p/%"PRIu64" no transaction to inspect",
tx.tx_ptr, tx_id_min);
tx_id_min++; // next (if any) run look for +1
goto next;
}
tx_id_min = tx.tx_id + 1; // next look for cur + 1
tx_inspected++;
SCLogDebug("%p/%" PRIu64 " txd flags %02x", tx.tx_ptr, tx_id_min, tx.tx_data_ptr->flags);
bool do_sort = false; // do we need to sort the tx candidate list?
uint32_t array_idx = 0;
uint32_t total_rules = det_ctx->match_array_cnt;
total_rules += (tx.de_state ? tx.de_state->cnt : 0);
/* run prefilter engines and merge results into a candidates array */
if (sgh->tx_engines) {
PACKET_PROFILING_DETECT_START(p, PROF_DETECT_PF_TX);
DetectRunPrefilterTx(det_ctx, sgh, p, ipproto, flow_flags, alproto,
alstate, &tx);
PACKET_PROFILING_DETECT_END(p, PROF_DETECT_PF_TX);
SCLogDebug("%p/%"PRIu64" rules added from prefilter: %u candidates",
tx.tx_ptr, tx.tx_id, det_ctx->pmq.rule_id_array_cnt);
total_rules += det_ctx->pmq.rule_id_array_cnt;
if (!(RuleMatchCandidateTxArrayHasSpace(det_ctx, total_rules))) {
RuleMatchCandidateTxArrayExpand(det_ctx, total_rules);
}
for (uint32_t i = 0; i < det_ctx->pmq.rule_id_array_cnt; i++) {
const Signature *s = de_ctx->sig_array[det_ctx->pmq.rule_id_array[i]];
const SigIntId id = s->num;
det_ctx->tx_candidates[array_idx].s = s;
det_ctx->tx_candidates[array_idx].id = id;
det_ctx->tx_candidates[array_idx].flags = NULL;
det_ctx->tx_candidates[array_idx].stream_reset = 0;
array_idx++;
}
PMQ_RESET(&det_ctx->pmq);
} else {
if (!(RuleMatchCandidateTxArrayHasSpace(det_ctx, total_rules))) {
RuleMatchCandidateTxArrayExpand(det_ctx, total_rules);
}
}
/* merge 'state' rules from the regular prefilter */
#ifdef PROFILING
uint32_t x = array_idx;
#endif
RuleMatchCandidateMergeStateRules(det_ctx, &array_idx);
/* merge stored state into results */
if (tx.de_state != NULL) {
const uint32_t old = array_idx;
/* if tx.de_state->flags has 'new file' set and sig below has
* 'file inspected' flag, reset the file part of the state */
const bool have_new_file = (tx.de_state->flags & DETECT_ENGINE_STATE_FLAG_FILE_NEW);
if (have_new_file) {
SCLogDebug("%p/%"PRIu64" destate: need to consider new file",
tx.tx_ptr, tx.tx_id);
tx.de_state->flags &= ~DETECT_ENGINE_STATE_FLAG_FILE_NEW;
}
SigIntId state_cnt = 0;
DeStateStore *tx_store = tx.de_state->head;
for (; tx_store != NULL; tx_store = tx_store->next) {
SCLogDebug("tx_store %p", tx_store);
SigIntId store_cnt = 0;
for (store_cnt = 0;
store_cnt < DE_STATE_CHUNK_SIZE && state_cnt < tx.de_state->cnt;
store_cnt++, state_cnt++)
{
DeStateStoreItem *item = &tx_store->store[store_cnt];
SCLogDebug("rule id %u, inspect_flags %u", item->sid, item->flags);
if (have_new_file && (item->flags & DE_STATE_FLAG_FILE_INSPECT)) {
/* remove part of the state. File inspect engine will now
* be able to run again */
item->flags &= ~(DE_STATE_FLAG_SIG_CANT_MATCH|DE_STATE_FLAG_FULL_INSPECT|DE_STATE_FLAG_FILE_INSPECT);
SCLogDebug("rule id %u, post file reset inspect_flags %u", item->sid, item->flags);
}
det_ctx->tx_candidates[array_idx].s = de_ctx->sig_array[item->sid];
det_ctx->tx_candidates[array_idx].id = item->sid;
det_ctx->tx_candidates[array_idx].flags = &item->flags;
det_ctx->tx_candidates[array_idx].stream_reset = 0;
array_idx++;
}
}
do_sort |= (old && old != array_idx); // sort if continue list adds sids
SCLogDebug("%p/%" PRIu64 " rules added from 'continue' list: %u", tx.tx_ptr, tx.tx_id,
array_idx - old);
}
if (do_sort) {
qsort(det_ctx->tx_candidates, array_idx, sizeof(RuleMatchCandidateTx),
DetectRunTxSortHelper);
}
#ifdef PROFILING
if (array_idx >= de_ctx->profile_match_logging_threshold)
RulesDumpTxMatchArray(det_ctx, scratch->sgh, p, tx.tx_id, array_idx, x);
#endif
det_ctx->tx_id = tx.tx_id;
det_ctx->tx_id_set = true;
det_ctx->p = p;
#ifdef DEBUG
for (uint32_t i = 0; i < array_idx; i++) {
RuleMatchCandidateTx *can = &det_ctx->tx_candidates[i];
const Signature *s = det_ctx->tx_candidates[i].s;
SCLogDebug("%u: sid %u flags %p", i, s->id, can->flags);
}
#endif
bool skip_fw_hook = false;
uint8_t skip_before_progress = 0;
bool fw_next_progress_missing = false;
/* if there are no rules / rule candidates, make sure we don't
* invoke the default drop */
if (have_fw_rules && array_idx == 0 && (tx.tx_data_ptr->flags & APP_LAYER_TX_ACCEPT)) {
fw_verdicted++;
/* current tx is the last we have, append a blank accept:packet */
if (total_txs == tx.tx_id + 1) {
DetectRunAppendDefaultAccept(det_ctx, p);
return;
}
goto next;
}
bool tx_fw_verdict = false;
/* run rules: inspect the match candidates */
for (uint32_t i = 0; i < array_idx; i++) {
RuleMatchCandidateTx *can = &det_ctx->tx_candidates[i];
const Signature *s = det_ctx->tx_candidates[i].s;
uint32_t *inspect_flags = det_ctx->tx_candidates[i].flags;
bool break_out_of_app_filter = false;
SCLogDebug("%" PRIu64 ": sid:%u: %s tx %u/%u/%u sig %u", p->pcap_cnt, s->id,
flow_flags & STREAM_TOSERVER ? "toserver" : "toclient", tx.tx_progress,
tx.detect_progress, tx.detect_progress_orig, s->app_progress_hook);
/* deduplicate: rules_array is sorted, but not deduplicated:
* both mpm and stored state could give us the same sid.
* As they are back to back in that case we can check for it
* here. We select the stored state one as that comes first
* in the array. */
while ((i + 1) < array_idx &&
det_ctx->tx_candidates[i].s == det_ctx->tx_candidates[i + 1].s) {
SCLogDebug("%p/%" PRIu64 " inspecting SKIP NEXT: sid %u (%u), flags %08x",
tx.tx_ptr, tx.tx_id, s->id, s->num, inspect_flags ? *inspect_flags : 0);
i++;
}
/* skip fw rules if we're in accept:tx mode */
if (have_fw_rules && (tx.tx_data_ptr->flags & APP_LAYER_TX_ACCEPT)) {
/* append a blank accept:packet action for the APP_LAYER_TX_ACCEPT,
* if this is the last tx */
if (!tx_fw_verdict) {
const bool accept_tx_applies_to_packet = total_txs == tx.tx_id + 1;
if (accept_tx_applies_to_packet) {
SCLogDebug("accept:(tx|hook): should be applied to the packet");
DetectRunAppendDefaultAccept(det_ctx, p);
}
}
tx_fw_verdict = true;
if (s->flags & SIG_FLAG_FIREWALL) {
SCLogDebug("APP_LAYER_TX_ACCEPT, so skip rule");
continue;
}
/* threat detect rules will be inspected */
}
SCLogDebug("%p/%"PRIu64" inspecting: sid %u (%u), flags %08x",
tx.tx_ptr, tx.tx_id, s->id, s->num, inspect_flags ? *inspect_flags : 0);
if (inspect_flags) {
if (*inspect_flags & (DE_STATE_FLAG_FULL_INSPECT|DE_STATE_FLAG_SIG_CANT_MATCH)) {
SCLogDebug("%p/%"PRIu64" inspecting: sid %u (%u), flags %08x ALREADY COMPLETE",
tx.tx_ptr, tx.tx_id, s->id, s->num, *inspect_flags);
continue;
}
}
if (inspect_flags) {
/* continue previous inspection */
SCLogDebug("%p/%" PRIu64 " Continuing sid %u", tx.tx_ptr, tx.tx_id, s->id);
} else {
/* start new inspection */
SCLogDebug("%p/%"PRIu64" Start sid %u", tx.tx_ptr, tx.tx_id, s->id);
}
bool last_for_progress = false;
if (have_fw_rules) {
int fw_r = DetectRunTxCheckFirewallPolicy(det_ctx, p, f, &tx, s, i, array_idx,
&skip_fw_hook, skip_before_progress, &last_for_progress,
&fw_next_progress_missing);
if (fw_r == -1)
continue;
if (fw_r == 1)
break;
}
/* call individual rule inspection */
RULE_PROFILING_START(p);
const int r = DetectRunTxInspectRule(tv, de_ctx, det_ctx, p, f, flow_flags,
alstate, &tx, s, inspect_flags, can, scratch);
if (r == 1) {
/* match */
DetectRunPostMatch(tv, det_ctx, p, s);
/* see if we need to apply tx/hook accept to the packet. This can be needed when
* we've completed the inspection so far for an incomplete tx, and an accept:tx or
* accept:hook is the last match.*/
const bool fw_accept_to_packet = ApplyAcceptToPacket(total_txs, &tx, s);
uint8_t alert_flags = (PACKET_ALERT_FLAG_STATE_MATCH | PACKET_ALERT_FLAG_TX);
if (fw_accept_to_packet) {
SCLogDebug("accept:(tx|hook): should be applied to the packet");
alert_flags |= PACKET_ALERT_FLAG_APPLY_ACTION_TO_PACKET;
}
SCLogDebug("%p/%"PRIu64" sig %u (%u) matched", tx.tx_ptr, tx.tx_id, s->id, s->num);
AlertQueueAppend(det_ctx, s, p, tx.tx_id, alert_flags);
if ((s->flags & SIG_FLAG_FIREWALL) && (s->action & ACTION_ACCEPT)) {
break_out_of_app_filter = ApplyAccept(p, flow_flags, s, &tx, tx_end_state,
fw_next_progress_missing, &tx_fw_verdict, &skip_fw_hook,
&skip_before_progress);
}
} else if (last_for_progress) {
SCLogDebug("sid %u: not a match: %s rule, last_for_progress %s", s->id,
(s->flags & SIG_FLAG_FIREWALL) ? "firewall" : "regular",
BOOL2STR(last_for_progress));
if (s->flags & SIG_FLAG_FIREWALL) {
SCLogDebug("%" PRIu64 ": %s default drop for progress", p->pcap_cnt,
flow_flags & STREAM_TOSERVER ? "toserver" : "toclient");
/* if this rule was the last for our progress state, and it didn't match,
* we have to invoke the default drop policy. */
PacketDrop(p, ACTION_DROP, PKT_DROP_REASON_DEFAULT_APP_POLICY);
p->flow->flags |= FLOW_ACTION_DROP;
break_out_of_app_filter = true;
tx_fw_verdict = true;
}
}
DetectVarProcessList(det_ctx, p->flow, p);
RULE_PROFILING_END(det_ctx, s, r, p);
if (det_ctx->post_rule_work_queue.len > 0) {
SCLogDebug("%p/%" PRIu64 " post_rule_work_queue len %u", tx.tx_ptr, tx.tx_id,
det_ctx->post_rule_work_queue.len);
/* run post match prefilter engines on work queue */
PrefilterPostRuleMatch(det_ctx, scratch->sgh, p, f);
uint32_t prev_array_idx = array_idx;
for (uint32_t j = 0; j < det_ctx->pmq.rule_id_array_cnt; j++) {
const Signature *ts = de_ctx->sig_array[det_ctx->pmq.rule_id_array[j]];
if (ts->app_inspect != NULL) {
const SigIntId id = ts->num;
det_ctx->tx_candidates[array_idx].s = ts;
det_ctx->tx_candidates[array_idx].id = id;
det_ctx->tx_candidates[array_idx].flags = NULL;
det_ctx->tx_candidates[array_idx].stream_reset = 0;
array_idx++;
SCLogDebug("%p/%" PRIu64 " rule %u (%u) added from 'post match' prefilter",
tx.tx_ptr, tx.tx_id, ts->id, id);
}
}
SCLogDebug("%p/%" PRIu64 " rules added from 'post match' prefilter: %u", tx.tx_ptr,
tx.tx_id, array_idx - prev_array_idx);
if (prev_array_idx != array_idx) {
/* sort, but only part of array we're still going to process */
qsort(det_ctx->tx_candidates + i, array_idx - i, sizeof(RuleMatchCandidateTx),
DetectRunTxSortHelper);
}
det_ctx->post_rule_work_queue.len = 0;
PMQ_RESET(&det_ctx->pmq);
}
if (break_out_of_app_filter)
break;
}
if (tx_fw_verdict)
fw_verdicted++;
det_ctx->tx_id = 0;
det_ctx->tx_id_set = false;
det_ctx->p = NULL;
/* see if we have any updated state to store in the tx */
/* this side of the tx is done */
if (tx.tx_progress >= tx.tx_end_state) {
SCLogDebug("%" PRIu64 ": %s tx done", p->pcap_cnt,
flow_flags & STREAM_TOSERVER ? "toserver" : "toclient");
const uint8_t inspected_flag = (flow_flags & STREAM_TOSERVER)
? APP_LAYER_TX_INSPECTED_TS
: APP_LAYER_TX_INSPECTED_TC;
tx.tx_data_ptr->flags |= inspected_flag;
SCLogDebug("%p/%" PRIu64 " tx is done for direction %s. Progress %02x", tx.tx_ptr,
tx.tx_id, flow_flags & STREAM_TOSERVER ? "toserver" : "toclient",
tx.detect_progress);
}
if (tx.detect_progress != tx.detect_progress_orig) {
SCLogDebug("%" PRIu64 ": %s tx state change %u -> %u", p->pcap_cnt,
flow_flags & STREAM_TOSERVER ? "toserver" : "toclient", tx.detect_progress_orig,
tx.detect_progress);
SCLogDebug("%p/%" PRIu64 " Storing new progress %02x (was %02x)", tx.tx_ptr, tx.tx_id,
tx.detect_progress, tx.detect_progress_orig);
StoreDetectProgress(&tx, flow_flags, tx.detect_progress);
}
InspectionBufferClean(det_ctx);
next:
if (!ires.has_next)
break;
}
/* apply default policy if there were txs to inspect, we have fw rules and non of the rules
* applied a policy. */
SCLogDebug("packet %" PRIu64 ": tx_inspected %u fw_verdicted %u", p->pcap_cnt, tx_inspected,
fw_verdicted);
if (tx_inspected && have_fw_rules && tx_inspected != fw_verdicted) {
SCLogDebug("%" PRIu64 ": %s default drop", p->pcap_cnt,
flow_flags & STREAM_TOSERVER ? "toserver" : "toclient");
PacketDrop(p, ACTION_DROP, PKT_DROP_REASON_DEFAULT_APP_POLICY);
p->flow->flags |= FLOW_ACTION_DROP;
return;
}
/* if all tables have been bypassed, we accept:packet */
if (tx_inspected == 0 && fw_verdicted == 0 && have_fw_rules) {
DetectRunAppendDefaultAccept(det_ctx, p);
}
}
static void DetectRunFrames(ThreadVars *tv, DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx,
Packet *p, Flow *f, DetectRunScratchpad *scratch)
{
const SigGroupHead *const sgh = scratch->sgh;
const AppProto alproto = f->alproto;
/* for TCP, limit inspection to pseudo packets or real packet that did
* an app-layer update. */
if (p->proto == IPPROTO_TCP && !PKT_IS_PSEUDOPKT(p) &&
((PKT_IS_TOSERVER(p) && (f->flags & FLOW_TS_APP_UPDATED) == 0) ||
(PKT_IS_TOCLIENT(p) && (f->flags & FLOW_TC_APP_UPDATED) == 0))) {
SCLogDebug("pcap_cnt %" PRIu64 ": %s: skip frame inspection for TCP w/o APP UPDATE",
p->pcap_cnt, PKT_IS_TOSERVER(p) ? "toserver" : "toclient");
return;
}
FramesContainer *frames_container = AppLayerFramesGetContainer(f);
if (frames_container == NULL) {
return;
}
Frames *frames;
if (PKT_IS_TOSERVER(p)) {
frames = &frames_container->toserver;
} else {
frames = &frames_container->toclient;
}
for (uint32_t idx = 0; idx < frames->cnt; idx++) {
SCLogDebug("frame %u", idx);
Frame *frame = FrameGetByIndex(frames, idx);
if (frame == NULL) {
continue;
}
det_ctx->frame_inspect_progress = 0;
uint32_t array_idx = 0;
uint32_t total_rules = det_ctx->match_array_cnt;
/* run prefilter engines and merge results into a candidates array */
if (sgh->frame_engines) {
// PACKET_PROFILING_DETECT_START(p, PROF_DETECT_PF_TX);
DetectRunPrefilterFrame(det_ctx, sgh, p, frames, frame, alproto);
// PACKET_PROFILING_DETECT_END(p, PROF_DETECT_PF_TX);
SCLogDebug("%p/%" PRIi64 " rules added from prefilter: %u candidates", frame, frame->id,
det_ctx->pmq.rule_id_array_cnt);
total_rules += det_ctx->pmq.rule_id_array_cnt;
if (!(RuleMatchCandidateTxArrayHasSpace(
det_ctx, total_rules))) { // TODO is it safe to overload?
RuleMatchCandidateTxArrayExpand(det_ctx, total_rules);
}
for (uint32_t i = 0; i < det_ctx->pmq.rule_id_array_cnt; i++) {
const Signature *s = de_ctx->sig_array[det_ctx->pmq.rule_id_array[i]];
const SigIntId id = s->num;
det_ctx->tx_candidates[array_idx].s = s;
det_ctx->tx_candidates[array_idx].id = id;
det_ctx->tx_candidates[array_idx].flags = NULL;
det_ctx->tx_candidates[array_idx].stream_reset = 0;
array_idx++;
}
PMQ_RESET(&det_ctx->pmq);
}
/* merge 'state' rules from the regular prefilter */
uint32_t x = array_idx;
for (uint32_t i = 0; i < det_ctx->match_array_cnt; i++) {
const Signature *s = det_ctx->match_array[i];
if (s->frame_inspect != NULL) {
const SigIntId id = s->num;
det_ctx->tx_candidates[array_idx].s = s;
det_ctx->tx_candidates[array_idx].id = id;
det_ctx->tx_candidates[array_idx].flags = NULL;
det_ctx->tx_candidates[array_idx].stream_reset = 0;
array_idx++;
SCLogDebug("%p/%" PRIi64 " rule %u (%u) added from 'match' list", frame, frame->id,
s->id, id);
}
}
SCLogDebug("%p/%" PRIi64 " rules added from 'match' list: %u", frame, frame->id,
array_idx - x);
(void)x;
/* run rules: inspect the match candidates */
for (uint32_t i = 0; i < array_idx; i++) {
const Signature *s = det_ctx->tx_candidates[i].s;
/* deduplicate: rules_array is sorted, but not deduplicated.
* As they are back to back in that case we can check for it
* here. We select the stored state one as that comes first
* in the array. */
while ((i + 1) < array_idx &&
det_ctx->tx_candidates[i].s == det_ctx->tx_candidates[i + 1].s) {
i++;
}
SCLogDebug("%p/%" PRIi64 " inspecting: sid %u (%u)", frame, frame->id, s->id, s->num);
/* start new inspection */
SCLogDebug("%p/%" PRIi64 " Start sid %u", frame, frame->id, s->id);
/* call individual rule inspection */
RULE_PROFILING_START(p);
bool r = DetectRunInspectRuleHeader(p, f, s, s->flags, s->proto.flags);
if (r) {
r = DetectRunFrameInspectRule(tv, det_ctx, s, f, p, frames, frame);
if (r) {
/* match */
DetectRunPostMatch(tv, det_ctx, p, s);
uint8_t alert_flags = (PACKET_ALERT_FLAG_STATE_MATCH | PACKET_ALERT_FLAG_FRAME);
det_ctx->frame_id = frame->id;
SCLogDebug(
"%p/%" PRIi64 " sig %u (%u) matched", frame, frame->id, s->id, s->num);
if (frame->flags & FRAME_FLAG_TX_ID_SET) {
alert_flags |= PACKET_ALERT_FLAG_TX;
}
AlertQueueAppend(det_ctx, s, p, frame->tx_id, alert_flags);
}
}
DetectVarProcessList(det_ctx, p->flow, p);
RULE_PROFILING_END(det_ctx, s, r, p);
}
/* update Frame::inspect_progress here instead of in the code above. The reason is that a
* frame might be used more than once in buffers with transforms. */
if (frame->inspect_progress < det_ctx->frame_inspect_progress) {
frame->inspect_progress = det_ctx->frame_inspect_progress;
SCLogDebug("frame->inspect_progress: %" PRIu64 " -> updated", frame->inspect_progress);
} else {
SCLogDebug(
"frame->inspect_progress: %" PRIu64 " -> not updated", frame->inspect_progress);
}
SCLogDebug("%p/%" PRIi64 " rules inspected, running cleanup", frame, frame->id);
InspectionBufferClean(det_ctx);
}
}
static DetectEngineThreadCtx *GetTenantById(HashTable *h, uint32_t id)
{
/* technically we need to pass a DetectEngineThreadCtx struct with the
* tenant_id member. But as that member is the first in the struct, we
* can use the id directly. */
return HashTableLookup(h, &id, 0);
}
static void DetectFlow(ThreadVars *tv,
DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx,
Packet *p)
{
Flow *const f = p->flow;
/* we check the flow drop here, and not the packet drop. This is
* to allow stream engine "invalid" drop packets to still be
* evaluated by the stream event rules. */
if (f->flags & FLOW_ACTION_DROP) {
DEBUG_VALIDATE_BUG_ON(!(PKT_IS_PSEUDOPKT(p)) && !PacketCheckAction(p, ACTION_DROP));
SCReturn;
}
/* in firewall mode, we still need to run the fw rulesets even for exception policy pass */
bool skip = false;
if (de_ctx->flags & DE_HAS_FIREWALL) {
skip = (f->flags & (FLOW_ACTION_ACCEPT));
} else {
skip = (p->flags & PKT_NOPACKET_INSPECTION || f->flags & (FLOW_ACTION_PASS));
}
if (skip) {
/* enfore prior accept:flow */
if (f->flags & FLOW_ACTION_ACCEPT) {
p->action |= ACTION_ACCEPT;
}
/* hack: if we are in pass the entire flow mode, we need to still
* update the inspect_id forward. So test for the condition here,
* and call the update code if necessary. */
const int pass = (f->flags & (FLOW_ACTION_PASS | FLOW_ACTION_ACCEPT));
if (pass) {
uint8_t flags = STREAM_FLAGS_FOR_PACKET(p);
flags = FlowGetDisruptionFlags(f, flags);
if (f->alstate) {
AppLayerParserSetTransactionInspectId(f, f->alparser, f->alstate, flags, true);
}
}
SCLogDebug("p->pcap %"PRIu64": no detection on packet, "
"PKT_NOPACKET_INSPECTION is set", p->pcap_cnt);
return;
}
/* see if the packet matches one or more of the sigs */
DetectRun(tv, de_ctx, det_ctx, p);
}
static void DetectNoFlow(ThreadVars *tv,
DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx,
Packet *p)
{
/* No need to perform any detection on this packet, if the given flag is set.*/
if ((p->flags & PKT_NOPACKET_INSPECTION) || (PacketCheckAction(p, ACTION_DROP))) {
return;
}
/* see if the packet matches one or more of the sigs */
DetectRun(tv, de_ctx, det_ctx, p);
}
/** \brief Detection engine thread wrapper.
* \param tv thread vars
* \param p packet to inspect
* \param data thread specific data
* \param pq packet queue
* \retval TM_ECODE_FAILED error
* \retval TM_ECODE_OK ok
*/
TmEcode Detect(ThreadVars *tv, Packet *p, void *data)
{
DEBUG_VALIDATE_PACKET(p);
DetectEngineCtx *de_ctx = NULL;
DetectEngineThreadCtx *det_ctx = (DetectEngineThreadCtx *)data;
if (det_ctx == NULL) {
printf("ERROR: Detect has no thread ctx\n");
goto error;
}
if (unlikely(SC_ATOMIC_GET(det_ctx->so_far_used_by_detect) == 0)) {
(void)SC_ATOMIC_SET(det_ctx->so_far_used_by_detect, 1);
SCLogDebug("Detect Engine using new det_ctx - %p",
det_ctx);
}
/* if in MT mode _and_ we have tenants registered, use
* MT logic. */
if (det_ctx->mt_det_ctxs_cnt > 0 && det_ctx->TenantGetId != NULL)
{
uint32_t tenant_id = p->tenant_id;
if (tenant_id == 0)
tenant_id = det_ctx->TenantGetId(det_ctx, p);
if (tenant_id > 0 && tenant_id < det_ctx->mt_det_ctxs_cnt) {
p->tenant_id = tenant_id;
det_ctx = GetTenantById(det_ctx->mt_det_ctxs_hash, tenant_id);
if (det_ctx == NULL)
return TM_ECODE_OK;
de_ctx = det_ctx->de_ctx;
if (de_ctx == NULL)
return TM_ECODE_OK;
if (unlikely(SC_ATOMIC_GET(det_ctx->so_far_used_by_detect) == 0)) {
(void)SC_ATOMIC_SET(det_ctx->so_far_used_by_detect, 1);
SCLogDebug("MT de_ctx %p det_ctx %p (tenant %u)", de_ctx, det_ctx, tenant_id);
}
} else {
/* use default if no tenants are registered for this packet */
de_ctx = det_ctx->de_ctx;
}
} else {
de_ctx = det_ctx->de_ctx;
}
if (p->flow) {
DetectFlow(tv, de_ctx, det_ctx, p);
} else {
DetectNoFlow(tv, de_ctx, det_ctx, p);
}
#ifdef PROFILE_RULES
/* aggregate statistics */
struct timeval ts;
gettimeofday(&ts, NULL);
if (ts.tv_sec != det_ctx->rule_perf_last_sync) {
SCProfilingRuleThreatAggregate(det_ctx);
det_ctx->rule_perf_last_sync = ts.tv_sec;
}
#endif
return TM_ECODE_OK;
error:
return TM_ECODE_FAILED;
}
/** \brief disable file features we don't need
* Called if we have no detection engine.
*/
void DisableDetectFlowFileFlags(Flow *f)
{
DetectPostInspectFileFlagsUpdate(f, NULL /* no sgh */, STREAM_TOSERVER);
DetectPostInspectFileFlagsUpdate(f, NULL /* no sgh */, STREAM_TOCLIENT);
}
#ifdef UNITTESTS
/**
* \brief wrapper for old tests
*/
void SigMatchSignatures(
ThreadVars *tv, DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx, Packet *p)
{
if (p->flow) {
DetectFlow(tv, de_ctx, det_ctx, p);
} else {
DetectNoFlow(tv, de_ctx, det_ctx, p);
}
}
#endif
/*
* TESTS
*/
#ifdef UNITTESTS
#include "tests/detect.c"
#endif