view util/paths.lua @ 12181:783056b4e448 0.11 0.11.12

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.
author Jonas Schäfer <jonas@wielicki.name>
date Mon, 10 Jan 2022 18:23:54 +0100
parents 2dc8dbd0940e
children 91085371cfc5
line wrap: on
line source

local t_concat = table.concat;

local path_sep = package.config:sub(1,1);

local path_util = {}

-- Helper function to resolve relative paths (needed by config)
function path_util.resolve_relative_path(parent_path, path)
	if path then
		-- Some normalization
		parent_path = parent_path:gsub("%"..path_sep.."+$", "");
		path = path:gsub("^%.%"..path_sep.."+", "");

		local is_relative;
		if path_sep == "/" and path:sub(1,1) ~= "/" then
			is_relative = true;
		elseif path_sep == "\\" and (path:sub(1,1) ~= "/" and (path:sub(2,3) ~= ":\\" and path:sub(2,3) ~= ":/")) then
			is_relative = true;
		end
		if is_relative then
			return parent_path..path_sep..path;
		end
	end
	return path;
end

-- Helper function to convert a glob to a Lua pattern
function path_util.glob_to_pattern(glob)
	return "^"..glob:gsub("[%p*?]", function (c)
		if c == "*" then
			return ".*";
		elseif c == "?" then
			return ".";
		else
			return "%"..c;
		end
	end).."$";
end

function path_util.join(...)
	return t_concat({...}, path_sep);
end

return path_util;