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.
-- Storage Interface API Description
--
-- This is written as a TypedLua description
-- Key-Value stores (the default)
interface keyval_store
get : ( self, string? ) -> (any) | (nil, string)
set : ( self, string?, any ) -> (boolean) | (nil, string)
end
-- Map stores (key-key-value stores)
interface map_store
get : ( self, string?, any ) -> (any) | (nil, string)
set : ( self, string?, any, any ) -> (boolean) | (nil, string)
set_keys : ( self, string?, { any : any }) -> (boolean) | (nil, string)
remove : {}
end
-- Archive stores
typealias archive_query = {
"start" : number?, -- timestamp
"end" : number?, -- timestamp
"with" : string?,
"after" : string?, -- archive id
"before" : string?, -- archive id
"total" : boolean?,
}
interface archive_store
-- Optional set of capabilities
caps : {
-- Optional total count of matching items returned as second return value from :find()
"total" : boolean?,
}?
-- Add to the archive
append : ( self, string?, string?, any, number?, string? ) -> (string) | (nil, string)
-- Iterate over archive
find : ( self, string?, archive_query? ) -> ( () -> ( string, any, number?, string? ), integer? )
-- Removal of items. API like find. Optional?
delete : ( self, string?, archive_query? ) -> (boolean) | (number) | (nil, string)
-- Array of dates which do have messages (Optional?)
dates : ( self, string? ) -> ({ string }) | (nil, string)
end
-- This represents moduleapi
interface module
-- If the first string is omitted then the name of the module is used
-- The second string is one of "keyval" (default), "map" or "archive"
open_store : (self, string?, string?) -> (keyval_store) | (map_store) | (archive_store) | (nil, string)
-- Other module methods omitted
end
module : module