osmocom
/
wireshark
11
0
Fork 1
Code Issues Pull Requests Projects Releases Wiki Activity

MQTT: Fix heuristic subdissector call 

Modify the dissector to call heuristic subdissectors after both
UAT configured and media type subdissectors have been attempted.
This commit is contained in:
Graham Bloice 2021-04-12 20:43:01 +01:00
parent a92265c48a
commit 5b70d58502
1 changed files with 18 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
epan/dissectors/packet-mqtt.c
View File

@ -685,7 +685,7 @@ UAT_CSTRING_CB_DEF(message_decode, topic_pattern, mqtt_message_decode_t)
UAT_VS_DEF(message_decode, msg_decoding, mqtt_message_decode_t, guint, MSG_DECODING_NONE, "none")
UAT_PROTO_DEF(message_decode, payload_proto, payload_proto, payload_proto_name, mqtt_message_decode_t)
static void mqtt_user_decode_message(proto_tree *tree, proto_tree *mqtt_tree, packet_info *pinfo, const guint8 *topic_str, tvbuff_t *msg_tvb)
static gboolean mqtt_user_decode_message(proto_tree *tree, proto_tree *mqtt_tree, packet_info *pinfo, const guint8 *topic_str, tvbuff_t *msg_tvb)
{
mqtt_message_decode_t *message_decode_entry = NULL;
size_t topic_str_len = strlen(topic_str);
@ -695,7 +695,7 @@ static void mqtt_user_decode_message(proto_tree *tree, proto_tree *mqtt_tree, pa
if (topic_str_len == 0)
{
/* No topic to match */
return;
return FALSE;
}
for (guint i = 0; i < num_mqtt_message_decodes && !match_found; i++)
@ -755,12 +755,8 @@ static void mqtt_user_decode_message(proto_tree *tree, proto_tree *mqtt_tree, pa
call_dissector(message_decode_entry->payload_proto, msg_tvb, pinfo, tree);
}
}
else {
/* No UAT match, try the heuristic dissectors, pass the topic string as data */
heur_dtbl_entry_t *hdtbl_entry;
gchar *sub_data = wmem_strdup(wmem_packet_scope(), (const gchar*)topic_str);
dissector_try_heuristic(mqtt_topic_subdissector, msg_tvb, pinfo, tree, &hdtbl_entry, sub_data);
}
return match_found;
}
static guint dissect_string(tvbuff_t *tvb, proto_tree *tree, guint offset, int hf_len, int hf_value)
@ -933,6 +929,7 @@ static int dissect_mqtt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, voi
mqtt_properties_t mqtt_properties = { 0 };
mqtt_properties_t mqtt_will_properties = { 0 };
guint offset = 0;
gboolean msg_handled = FALSE;
static int * const publish_fields[] = {
&hf_mqtt_msg_type,
@ -1224,14 +1221,24 @@ static int dissect_mqtt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, voi
if (num_mqtt_message_decodes > 0)
{
tvbuff_t *msg_tvb = tvb_new_subset_length(tvb, offset, mqtt_payload_len);
mqtt_user_decode_message(tree, mqtt_tree, pinfo, topic_str, msg_tvb);
msg_handled = mqtt_user_decode_message(tree, mqtt_tree, pinfo, topic_str, msg_tvb);
}
if (mqtt_properties.content_type)
{
tvbuff_t *msg_tvb = tvb_new_subset_length(tvb, offset, mqtt_payload_len);
dissector_try_string(media_type_dissector_table, mqtt_properties.content_type,
msg_tvb, pinfo, tree, NULL);
int bytes_read = dissector_try_string(media_type_dissector_table, mqtt_properties.content_type,
msg_tvb, pinfo, tree, NULL);
msg_handled = msg_handled | (bytes_read != 0);
}
/* No UAT or content property match, try the heuristic dissectors, pass the topic string as data */
if (!msg_handled) {
heur_dtbl_entry_t *hdtbl_entry;
tvbuff_t *msg_tvb = tvb_new_subset_length(tvb, offset, mqtt_payload_len);
gchar *sub_data = wmem_strdup(wmem_packet_scope(), (const gchar*)topic_str);
dissector_try_heuristic(mqtt_topic_subdissector, msg_tvb, pinfo, tree, &hdtbl_entry, sub_data);
}
break;