With EAP7.1.0.GA, there has been added a validator for 'max-post-size' attribute for listeners in undertow subsystem. This validator requires positive integer values starting with value 1. That means, you cannot disable 'max-post-size' for such listener using 0 value anymore.

In EAP6.4 and EAP7.0, it was possible to disable 'max-post-size' check with 0 value. I understand that we might not want to allow user to set this to 0 value as it might be a potentional security risk. Still, maybe we should relax this restriction as it was possible to configure it that way in previous versions of EAP.

Also there is a Knowledge Base article regarding to this feature, which we should update in case we won't reconsider our position.

Just for the record - quoting question from mailing list:

Dear Experts,

Based on KCS, the "max-post-size" in "http-listener" from "undertow" subsystem can be disabled by setting "0" to it, it worked for EAP 6.x and 7.0 GA.

But in EAP 7.1.0 GA, it didn't work:
~~~
[standalone@localhost:9990 /] /subsystem=undertow/server=default-server/http-listener=default/:write-attribute(name=max-post-size,value=0)
{
"outcome" => "failed",
"failure-description" => "WFLYCTL0117: 0 is an invalid value for parameter max-post-size. A minimum value of 1 is required",
"rolled-back" => true
}
~~~

By comparing schemas:
~~~
jboss-eap-7.0/docs/schema/wildfly-undertow_x_x.xsd:
<xs:attribute name="max-post-size" type="xs:long" default="0"/>
—
jboss-eap-7.1/docs/schema/wildfly-undertow_x_x.xsd:
<xs:attribute name="max-post-size" type="xs:long" default="10485760"/>
~~~
The behaviour changed.

And I found WFLY-6437 and JBEAP-3974, but failed to open links inside those.

So can I ask if "max-post-size" can be disabled in EAP 7.1.0 GA and the reason if possible?

Best Regards,
Zhang Xu