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-rw-r--r--src/detect-mqtt-unsubscribe-topic.c248
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diff --git a/src/detect-mqtt-unsubscribe-topic.c b/src/detect-mqtt-unsubscribe-topic.c
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+/* Copyright (C) 2020-2022 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 Sascha Steinbiss <sascha@steinbiss.name>
+ */
+
+#include "suricata-common.h"
+
+#include "app-layer.h"
+#include "app-layer-parser.h"
+
+#include "conf.h"
+#include "decode.h"
+#include "detect.h"
+#include "detect-content.h"
+#include "detect-parse.h"
+#include "detect-pcre.h"
+#include "detect-engine.h"
+#include "detect-engine-content-inspection.h"
+#include "detect-engine-mpm.h"
+#include "detect-engine-prefilter.h"
+#include "detect-mqtt-unsubscribe-topic.h"
+#include "util-unittest.h"
+#include "util-unittest-helper.h"
+
+#include "rust-bindings.h"
+
+#include "threads.h"
+
+#include "flow.h"
+#include "flow-util.h"
+#include "flow-var.h"
+
+#include "util-debug.h"
+#include "util-spm.h"
+#include "util-print.h"
+#include "util-profiling.h"
+
+static int DetectMQTTUnsubscribeTopicSetup(DetectEngineCtx *, Signature *, const char *);
+
+static int g_mqtt_unsubscribe_topic_buffer_id = 0;
+
+static uint32_t unsubscribe_topic_match_limit = 100;
+
+struct MQTTUnsubscribeTopicGetDataArgs {
+ uint32_t local_id;
+ void *txv;
+};
+
+static InspectionBuffer *MQTTUnsubscribeTopicGetData(DetectEngineThreadCtx *det_ctx,
+ const DetectEngineTransforms *transforms, Flow *f,
+ struct MQTTUnsubscribeTopicGetDataArgs *cbdata, int list_id)
+{
+ SCEnter();
+
+ InspectionBuffer *buffer =
+ InspectionBufferMultipleForListGet(det_ctx, list_id, cbdata->local_id);
+ if (buffer == NULL)
+ return NULL;
+ if (buffer->initialized)
+ return buffer;
+
+ const uint8_t *data;
+ uint32_t data_len;
+ if (rs_mqtt_tx_get_unsubscribe_topic(cbdata->txv, cbdata->local_id, &data, &data_len) == 0) {
+ InspectionBufferSetupMultiEmpty(buffer);
+ return NULL;
+ }
+
+ InspectionBufferSetupMulti(buffer, transforms, data, data_len);
+
+ SCReturnPtr(buffer, "InspectionBuffer");
+}
+
+static uint8_t DetectEngineInspectMQTTUnsubscribeTopic(DetectEngineCtx *de_ctx,
+ DetectEngineThreadCtx *det_ctx, const DetectEngineAppInspectionEngine *engine,
+ const Signature *s, Flow *f, uint8_t flags, void *alstate, void *txv, uint64_t tx_id)
+{
+ uint32_t local_id = 0;
+
+ const DetectEngineTransforms *transforms = NULL;
+ if (!engine->mpm) {
+ transforms = engine->v2.transforms;
+ }
+
+ while ((unsubscribe_topic_match_limit == 0) || local_id < unsubscribe_topic_match_limit) {
+ struct MQTTUnsubscribeTopicGetDataArgs cbdata = { local_id, txv, };
+ InspectionBuffer *buffer =
+ MQTTUnsubscribeTopicGetData(det_ctx, transforms, f, &cbdata, engine->sm_list);
+ if (buffer == NULL || buffer->inspect == NULL)
+ break;
+
+ det_ctx->buffer_offset = 0;
+ det_ctx->discontinue_matching = 0;
+ det_ctx->inspection_recursion_counter = 0;
+
+ const int match = DetectEngineContentInspection(de_ctx, det_ctx, s, engine->smd,
+ NULL, f,
+ (uint8_t *)buffer->inspect,
+ buffer->inspect_len,
+ buffer->inspect_offset, DETECT_CI_FLAGS_SINGLE,
+ DETECT_ENGINE_CONTENT_INSPECTION_MODE_STATE);
+ if (match == 1) {
+ return DETECT_ENGINE_INSPECT_SIG_MATCH;
+ }
+ local_id++;
+ }
+ return DETECT_ENGINE_INSPECT_SIG_NO_MATCH;
+}
+
+typedef struct PrefilterMpmMQTTUnsubscribeTopic {
+ int list_id;
+ const MpmCtx *mpm_ctx;
+ const DetectEngineTransforms *transforms;
+} PrefilterMpmMQTTUnsubscribeTopic;
+
+/** \brief MQTTUnsubscribeTopic MQTTUnsubscribeTopic Mpm prefilter callback
+ *
+ * \param det_ctx detection engine thread ctx
+ * \param p packet to inspect
+ * \param f flow to inspect
+ * \param txv tx to inspect
+ * \param pectx inspection context
+ */
+static void PrefilterTxMQTTUnsubscribeTopic(DetectEngineThreadCtx *det_ctx, const void *pectx,
+ Packet *p, Flow *f, void *txv, const uint64_t idx, const AppLayerTxData *_txd,
+ const uint8_t flags)
+{
+ SCEnter();
+
+ const PrefilterMpmMQTTUnsubscribeTopic *ctx = (const PrefilterMpmMQTTUnsubscribeTopic *)pectx;
+ const MpmCtx *mpm_ctx = ctx->mpm_ctx;
+ const int list_id = ctx->list_id;
+
+ uint32_t local_id = 0;
+ while ((unsubscribe_topic_match_limit == 0) || local_id < unsubscribe_topic_match_limit) {
+ struct MQTTUnsubscribeTopicGetDataArgs cbdata = { local_id, txv };
+ InspectionBuffer *buffer =
+ MQTTUnsubscribeTopicGetData(det_ctx, ctx->transforms, f, &cbdata, list_id);
+ if (buffer == NULL)
+ break;
+
+ if (buffer->inspect_len >= mpm_ctx->minlen) {
+ (void)mpm_table[mpm_ctx->mpm_type].Search(mpm_ctx,
+ &det_ctx->mtcu, &det_ctx->pmq,
+ buffer->inspect, buffer->inspect_len);
+ PREFILTER_PROFILING_ADD_BYTES(det_ctx, buffer->inspect_len);
+ }
+ local_id++;
+ }
+}
+
+static void PrefilterMpmMQTTUnsubscribeTopicFree(void *ptr)
+{
+ if (ptr != NULL)
+ SCFree(ptr);
+}
+
+static int PrefilterMpmMQTTUnsubscribeTopicRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh,
+ MpmCtx *mpm_ctx, const DetectBufferMpmRegistry *mpm_reg, int list_id)
+{
+ PrefilterMpmMQTTUnsubscribeTopic *pectx = SCCalloc(1, sizeof(*pectx));
+ if (pectx == NULL)
+ return -1;
+ pectx->list_id = list_id;
+ pectx->mpm_ctx = mpm_ctx;
+ pectx->transforms = &mpm_reg->transforms;
+
+ return PrefilterAppendTxEngine(de_ctx, sgh, PrefilterTxMQTTUnsubscribeTopic,
+ mpm_reg->app_v2.alproto, mpm_reg->app_v2.tx_min_progress,
+ pectx, PrefilterMpmMQTTUnsubscribeTopicFree, mpm_reg->pname);
+}
+
+/**
+ * \brief Registration function for keyword: mqtt.unsubscribe.topic
+ */
+void DetectMQTTUnsubscribeTopicRegister (void)
+{
+ sigmatch_table[DETECT_AL_MQTT_UNSUBSCRIBE_TOPIC].name = "mqtt.unsubscribe.topic";
+ sigmatch_table[DETECT_AL_MQTT_UNSUBSCRIBE_TOPIC].desc = "sticky buffer to match MQTT UNSUBSCRIBE topic";
+ sigmatch_table[DETECT_AL_MQTT_UNSUBSCRIBE_TOPIC].url = "/rules/mqtt-keywords.html#mqtt-unsubscribe-topic";
+ sigmatch_table[DETECT_AL_MQTT_UNSUBSCRIBE_TOPIC].Setup = DetectMQTTUnsubscribeTopicSetup;
+ sigmatch_table[DETECT_AL_MQTT_UNSUBSCRIBE_TOPIC].flags |= SIGMATCH_NOOPT;
+ sigmatch_table[DETECT_AL_MQTT_UNSUBSCRIBE_TOPIC].flags |= SIGMATCH_INFO_STICKY_BUFFER;
+
+ intmax_t val = 0;
+ if (ConfGetInt("app-layer.protocols.mqtt.unsubscribe-topic-match-limit", &val)) {
+ unsubscribe_topic_match_limit = val;
+ }
+ if (unsubscribe_topic_match_limit <= 0) {
+ SCLogDebug("Using unrestricted MQTT UNSUBSCRIBE topic matching");
+ } else {
+ SCLogDebug("Using MQTT UNSUBSCRIBE topic match-limit setting of: %i",
+ unsubscribe_topic_match_limit);
+ }
+
+ DetectAppLayerMpmRegister2("mqtt.unsubscribe.topic", SIG_FLAG_TOSERVER, 1,
+ PrefilterMpmMQTTUnsubscribeTopicRegister, NULL,
+ ALPROTO_MQTT, 1);
+
+ DetectAppLayerInspectEngineRegister2("mqtt.unsubscribe.topic",
+ ALPROTO_MQTT, SIG_FLAG_TOSERVER, 1,
+ DetectEngineInspectMQTTUnsubscribeTopic, NULL);
+
+ DetectBufferTypeSetDescriptionByName("mqtt.unsubscribe.topic",
+ "unsubscribe topic query");
+
+ g_mqtt_unsubscribe_topic_buffer_id = DetectBufferTypeGetByName("mqtt.unsubscribe.topic");
+
+ DetectBufferTypeSupportsMultiInstance("mqtt.unsubscribe.topic");
+}
+
+/**
+ * \brief setup the sticky buffer keyword used in the rule
+ *
+ * \param de_ctx Pointer to the Detection Engine Context
+ * \param s Pointer to the Signature to which the current keyword belongs
+ * \param str Should hold an empty string always
+ *
+ * \retval 0 On success
+ * \retval -1 On failure
+ */
+
+static int DetectMQTTUnsubscribeTopicSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
+{
+ if (DetectBufferSetActiveList(de_ctx, s, g_mqtt_unsubscribe_topic_buffer_id) < 0)
+ return -1;
+ if (DetectSignatureSetAppProto(s, ALPROTO_MQTT) < 0)
+ return -1;
+ return 0;
+}
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