As specified by the MQTT specification (MQTT-3.1.3-6), the client ID may be
empty. That means the length of the client ID string may be 0. However, The
MQTT parser does not support empty strings.
So, to fix the bug, the mqtt_read_string() function may now parse empty
string. 2 bytes must be found to decode the string length, but the length
may be 0 now. It is the caller responsibility to test the string emptiness
if necessary. In addition, in mqtt_parse_connect(), the client ID may be
empty now.
This patch should partely fix the issue #1310. It must be backported to 2.4.
Parsing of too long strings (> 127 characters) was buggy because of a wrong
cast on the length bytes. To fix the bug, we rely on mqtt_read_2byte_int()
function. This way, the string length is properly decoded.
This patch should partely fix the issue #1310. It must be backported to 2.4.
This patch implements a couple of converters to validate and extract data from a
MQTT (Message Queuing Telemetry Transport) message. The validation consists of a
few checks as well as "packet size" validation. The extraction can get any field
from the variable header and the payload.
This is limited to CONNECT and CONNACK packet types only. All other messages are
considered as invalid. It is not a problem for now because only the first packet
on each side can be parsed (CONNECT for the client and CONNACK for the server).
MQTT 3.1.1 and 5.0 are supported.
Reviewed and Fixed by Christopher Faulet <cfaulet@haproxy.com>
