1 files changed, 301 insertions, 0 deletions
diff --git a/src/detect-mqtt-connack-sessionpresent.c b/src/detect-mqtt-connack-sessionpresent.c
new file mode 100644
index 0000000..7ec902f
--- /dev/null
+++ b/src/detect-mqtt-connack-sessionpresent.c
@@ -0,0 +1,301 @@
+/* Copyright (C) 2020 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 "conf.h"
+#include "detect.h"
+#include "detect-parse.h"
+#include "detect-engine.h"
+#include "detect-engine-content-inspection.h"
+#include "detect-mqtt-connack-sessionpresent.h"
+#include "util-unittest.h"
+
+#include "rust.h"
+
+#define PARSE_REGEX "^true|false|yes|no$"
+static DetectParseRegex parse_regex;
+
+static int mqtt_connack_session_present_id = 0;
+
+static int DetectMQTTConnackSessionPresentMatch(DetectEngineThreadCtx *det_ctx,
+                               Flow *f, uint8_t flags, void *state,
+                               void *txv, const Signature *s,
+                               const SigMatchCtx *ctx);
+static int DetectMQTTConnackSessionPresentSetup (DetectEngineCtx *, Signature *, const char *);
+void MQTTConnackSessionPresentRegisterTests(void);
+void DetectMQTTConnackSessionPresentFree(DetectEngineCtx *de_ctx, void *);
+
+/**
+ * \brief Registration function for mqtt.connack.session_present: keyword
+ */
+void DetectMQTTConnackSessionPresentRegister (void)
+{
+    sigmatch_table[DETECT_AL_MQTT_CONNACK_SESSION_PRESENT].name = "mqtt.connack.session_present";
+    sigmatch_table[DETECT_AL_MQTT_CONNACK_SESSION_PRESENT].desc = "match MQTT CONNACK session present flag";
+    sigmatch_table[DETECT_AL_MQTT_CONNACK_SESSION_PRESENT].url = "/rules/mqtt-keywords.html#mqtt-connack-session-present";
+    sigmatch_table[DETECT_AL_MQTT_CONNACK_SESSION_PRESENT].AppLayerTxMatch = DetectMQTTConnackSessionPresentMatch;
+    sigmatch_table[DETECT_AL_MQTT_CONNACK_SESSION_PRESENT].Setup = DetectMQTTConnackSessionPresentSetup;
+    sigmatch_table[DETECT_AL_MQTT_CONNACK_SESSION_PRESENT].Free  = DetectMQTTConnackSessionPresentFree;
+#ifdef UNITTESTS
+    sigmatch_table[DETECT_AL_MQTT_CONNACK_SESSION_PRESENT].RegisterTests = MQTTConnackSessionPresentRegisterTests;
+#endif
+
+    DetectSetupParseRegexes(PARSE_REGEX, &parse_regex);
+
+    DetectAppLayerInspectEngineRegister2("mqtt.connack.session_present", ALPROTO_MQTT,
+            SIG_FLAG_TOSERVER, 1, DetectEngineInspectGenericList, NULL);
+
+    mqtt_connack_session_present_id = DetectBufferTypeGetByName("mqtt.connack.session_present");
+}
+
+/**
+ * \internal
+ * \brief Function to match session_present flag of an MQTT CONNACK message
+ *
+ * \param det_ctx Pointer to the pattern matcher thread.
+ * \param f       Pointer to the current flow.
+ * \param flags   Flags.
+ * \param state   App layer state.
+ * \param txv     Pointer to the transaction.
+ * \param s       Pointer to the Signature.
+ * \param ctx     Pointer to the sigmatch that we will cast into DetectMQTTConnackSessionPresentData.
+ *
+ * \retval 0 no match.
+ * \retval 1 match.
+ */
+static int DetectMQTTConnackSessionPresentMatch(DetectEngineThreadCtx *det_ctx,
+                               Flow *f, uint8_t flags, void *state,
+                               void *txv, const Signature *s,
+                               const SigMatchCtx *ctx)
+{
+    const bool *de = (const bool *)ctx;
+    bool value = false;
+
+    if (!de)
+        return 0;
+
+    if (rs_mqtt_tx_get_connack_sessionpresent(txv, &value) ==0 ) {
+        return 0;
+    }
+    if (value != *de) {
+        return 0;
+    }
+
+    return 1;
+}
+
+/**
+ * \internal
+ * \brief This function is used to parse options passed via mqtt.connack.session_present: keyword
+ *
+ * \param rawstr Pointer to the user provided options
+ *
+ * \retval de pointer to DetectMQTTConnackSessionPresentData on success
+ * \retval NULL on failure
+ */
+static bool *DetectMQTTConnackSessionPresentParse(const char *rawstr)
+{
+    bool *de = NULL;
+    de = SCMalloc(sizeof(bool));
+    if (unlikely(de == NULL))
+        return NULL;
+    *de = false;
+
+    if (strcmp(rawstr, "yes") == 0) {
+        *de = true;
+    } else if (strcmp(rawstr, "true") == 0) {
+        *de = true;
+    } else if (strcmp(rawstr, "no") == 0) {
+        *de = false;
+    } else if (strcmp(rawstr, "false") == 0) {
+        *de = false;
+    } else {
+        SCLogError("invalid session_present flag definition: %s", rawstr);
+        goto error;
+    }
+
+    return de;
+
+error:
+    /* de can't be NULL here */
+    SCFree(de);
+    return NULL;
+}
+
+/**
+ * \internal
+ * \brief this function is used to add the parsed type query into the current signature
+ *
+ * \param de_ctx pointer to the Detection Engine Context
+ * \param s pointer to the Current Signature
+ * \param rawstr pointer to the user provided options
+ *
+ * \retval 0 on Success
+ * \retval -1 on Failure
+ */
+static int DetectMQTTConnackSessionPresentSetup (DetectEngineCtx *de_ctx, Signature *s, const char *rawstr)
+{
+    bool *de = NULL;
+    SigMatch *sm = NULL;
+
+    if (DetectSignatureSetAppProto(s, ALPROTO_MQTT) < 0)
+        return -1;
+
+    de = DetectMQTTConnackSessionPresentParse(rawstr);
+    if (de == NULL)
+        goto error;
+
+    sm = SigMatchAlloc();
+    if (sm == NULL)
+        goto error;
+
+    sm->type = DETECT_AL_MQTT_CONNACK_SESSION_PRESENT;
+    sm->ctx = (SigMatchCtx *)de;
+
+    SigMatchAppendSMToList(s, sm, mqtt_connack_session_present_id);
+
+    return 0;
+
+error:
+    if (de != NULL)
+        SCFree(de);
+    if (sm != NULL)
+        SCFree(sm);
+    return -1;
+}
+
+/**
+ * \internal
+ * \brief this function will free memory associated with DetectMQTTConnackSessionPresentData
+ *
+ * \param de pointer to DetectMQTTConnackSessionPresentData
+ */
+void DetectMQTTConnackSessionPresentFree(DetectEngineCtx *de_ctx, void *de_ptr)
+{
+    if (de_ptr != NULL)
+        SCFree(de_ptr);
+}
+
+/*
+ * ONLY TESTS BELOW THIS COMMENT
+ */
+
+#ifdef UNITTESTS
+/**
+ * \test MQTTConnackSessionPresentTestParse01 is a test for a valid value
+ *
+ *  \retval 1 on success
+ *  \retval 0 on failure
+ */
+static int MQTTConnackSessionPresentTestParse01 (void)
+{
+    bool *de = NULL;
+
+    de = DetectMQTTConnackSessionPresentParse("yes");
+    FAIL_IF_NULL(de);
+    DetectMQTTConnackSessionPresentFree(NULL, de);
+
+    de = DetectMQTTConnackSessionPresentParse("true");
+    FAIL_IF_NULL(de);
+    DetectMQTTConnackSessionPresentFree(NULL, de);
+
+    de = DetectMQTTConnackSessionPresentParse("false");
+    FAIL_IF_NULL(de);
+    DetectMQTTConnackSessionPresentFree(NULL, de);
+
+    de = DetectMQTTConnackSessionPresentParse("no");
+    FAIL_IF_NULL(de);
+    DetectMQTTConnackSessionPresentFree(NULL, de);
+
+    PASS;
+}
+
+/**
+ * \test MQTTConnackSessionPresentTestParse02 is a test for an invalid value
+ *
+ *  \retval 1 on success
+ *  \retval 0 on failure
+ */
+static int MQTTConnackSessionPresentTestParse02 (void)
+{
+    bool *de = NULL;
+    de = DetectMQTTConnackSessionPresentParse("nix");
+    if (de) {
+        DetectMQTTConnackSessionPresentFree(NULL, de);
+        FAIL;
+    }
+
+    PASS;
+}
+
+/**
+ * \test MQTTConnackSessionPresentTestParse03 is a test for an invalid value
+ *
+ *  \retval 1 on success
+ *  \retval 0 on failure
+ */
+static int MQTTConnackSessionPresentTestParse03 (void)
+{
+    bool *de = NULL;
+    de = DetectMQTTConnackSessionPresentParse("");
+    if (de) {
+        DetectMQTTConnackSessionPresentFree(NULL, de);
+        FAIL;
+    }
+
+    PASS;
+}
+
+/**
+ * \test MQTTConnackSessionPresentTestParse04 is a test for an invalid value
+ *
+ *  \retval 1 on success
+ *  \retval 0 on failure
+ */
+static int MQTTConnackSessionPresentTestParse04 (void)
+{
+    bool *de = NULL;
+    de = DetectMQTTConnackSessionPresentParse(",");
+    if (de) {
+        DetectMQTTConnackSessionPresentFree(NULL, de);
+        FAIL;
+    }
+
+    PASS;
+}
+
+
+#endif /* UNITTESTS */
+
+/**
+ * \brief this function registers unit tests for MQTTConnackSessionPresent
+ */
+void MQTTConnackSessionPresentRegisterTests(void)
+{
+#ifdef UNITTESTS
+    UtRegisterTest("MQTTConnackSessionPresentTestParse01", MQTTConnackSessionPresentTestParse01);
+    UtRegisterTest("MQTTConnackSessionPresentTestParse02", MQTTConnackSessionPresentTestParse02);
+    UtRegisterTest("MQTTConnackSessionPresentTestParse03", MQTTConnackSessionPresentTestParse03);
+    UtRegisterTest("MQTTConnackSessionPresentTestParse04", MQTTConnackSessionPresentTestParse04);
+#endif /* UNITTESTS */
+}