util.xml: Do not allow doctypes, comments or processing instructions Yes. This is as bad as it sounds. CVE pending. In Prosody itself, this only affects mod_websocket, which uses util.xml to parse the <open/> frame, thus allowing unauthenticated remote DoS using Billion Laughs. However, third-party modules using util.xml may also be affected by this. This commit installs handlers which disallow the use of doctype declarations and processing instructions without any escape hatch. It, by default, also introduces such a handler for comments, however, there is a way to enable comments nontheless. This is because util.xml is used to parse human-facing data, where comments are generally a desirable feature, and also because comments are generally harmless.

     1

     2

Structure of a stanza:

     3

     4

     5

stanza {

     6

	--- properties ---

     7

	tags -- array of tags

     8

     9

	--- static methods ---

    10

	iq(attrs) -- 

    11

    12

	--- read-only methods ---

    13

	reply -- return new stanza with attributes of current stanza

    14

	child_with_name(string name) -- return the first child of the current tag with the matching name

    15

    16

	--- write methods ---

    17

	tag(name, sttrs) -- create a new child of the current tag, and set the child as current

    18

	up() -- move to the parent of the current tag

    19

	text(string) -- append a new text node to the current tag

    20

}