From 785d3273084026d308cfa92edf8832e24ec4193e Mon Sep 17 00:00:00 2001 From: Kim Alvefur Date: Thu, 20 Jan 2022 10:51:46 +0100 Subject: util.xml: Deduplicate handlers for restricted XML Makes the code more like util.xmppstream, allowing easier comparisons if we ever need to apply fixes in the future. --- util/xml.lua | 17 +++++------------ 1 file changed, 5 insertions(+), 12 deletions(-) diff --git a/util/xml.lua b/util/xml.lua index 72f1a26b..4327dfba 100644 --- a/util/xml.lua +++ b/util/xml.lua @@ -66,23 +66,16 @@ local parse_xml = (function() stanza:up(); end -- SECURITY: These two handlers, especially the Doctype one, are required to prevent exploits such as Billion Laughs. - function handler:StartDoctypeDecl() - if not self.stop or not self:stop() then - error("Failed to abort parsing"); - end - end - function handler:ProcessingInstruction() - if not self.stop or not self:stop() then + local function restricted_handler(parser) + if not parser.stop or not parser:stop() then error("Failed to abort parsing"); end end + handler.StartDoctypeDecl = restricted_handler; + handler.ProcessingInstruction = restricted_handler; if not options or not options.allow_comments then -- NOTE: comments are generally harmless and can be useful when parsing configuration files or other data, even user-provided data - function handler:Comment() - if not self.stop or not self:stop() then - error("Failed to abort parsing"); - end - end + handler.Comment = restricted_handler; end local parser = lxp.new(handler, ns_separator); local ok, err, line, col = parser:parse(xml); -- cgit v1.2.3