tree 1f07edac11bd3e43bde82615b999899c6346532e
parent edf94cbc52553abbb43e64686bfba024d4d62cff
author Christopher Faulet <cfaulet@haproxy.com> 1624887479 +0200
committer Christopher Faulet <cfaulet@haproxy.com> 1624890817 +0200

BUG/MINOR: mqtt: Support empty client ID in CONNECT message

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.

(cherry picked from commit 0de0becf0b024b6beca9c5f7e1ed8a08120d781c)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>