diff options
| author | Flavio Santes <flavio.santes@1byt3.com> | 2017-11-08 22:55:30 -0500 |
|---|---|---|
| committer | Stig Bjørlykke <stig@bjorlykke.org> | 2017-11-09 08:45:04 +0000 |
| commit | 43678551636f9845da4d52f48f8e82931f6b1c80 (patch) | |
| tree | 0568e5a469b3fe62f798be4ea8042b0387898734 /epan | |
| parent | afb252355bebee80673ea904c6b510aeaf10feb5 (diff) | |
dissector/mqtt: Rewrite the SUBSCRIBE payload size computation
- FIX: subtract the property length from the message length
- Replace the 'for' loop by a 'while' loop, now that the
arithmetic is done before.
TODO: It's a protocol error (v5.0)/violation (v3.1.1) not to
include the payload in the SUBSCRIBE control packet. It would
be nice to display a "malformed packet legend" in such that
case.
Change-Id: I99ef3862aa19b3a31ea03d1c194e54f489674115
Signed-off-by: Flavio Santes <flavio.santes@1byt3.com>
Reviewed-on: https://code.wireshark.org/review/24313
Petri-Dish: Stig Bjørlykke <stig@bjorlykke.org>
Tested-by: Petri Dish Buildbot
Reviewed-by: Stig Bjørlykke <stig@bjorlykke.org>
Diffstat (limited to 'epan')
| -rw-r--r-- | epan/dissectors/packet-mqtt.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/epan/dissectors/packet-mqtt.c b/epan/dissectors/packet-mqtt.c index 9894c21dc6..cee28a3c42 100644 --- a/epan/dissectors/packet-mqtt.c +++ b/epan/dissectors/packet-mqtt.c @@ -839,12 +839,19 @@ static int dissect_mqtt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, voi proto_tree_add_item(mqtt_tree, hf_mqtt_msgid, tvb, offset, 2, ENC_BIG_ENDIAN); offset += 2; + /* Subtract the Packet Id size to compute the Payload length */ + mqtt_msg_len -= 2; + if (mqtt->runtime_proto_version == MQTT_PROTO_V50) { - offset += dissect_mqtt_properties(tvb, mqtt_tree, offset); + guint32 mqtt_prop_offset = dissect_mqtt_properties(tvb, mqtt_tree, offset); + offset += mqtt_prop_offset; + + /* Subtract the Property offset to compute the Payload length */ + mqtt_msg_len -= mqtt_prop_offset; } - for(mqtt_msg_len -= 2; mqtt_msg_len > 0;) + while (mqtt_msg_len > 0) { mqtt_str_len = tvb_get_ntohs(tvb, offset); proto_tree_add_item(mqtt_tree, hf_mqtt_topic_len, tvb, offset, 2, ENC_BIG_ENDIAN); |