1 files changed, 118 insertions, 0 deletions
diff --git a/util/sslconfig.lua b/util/sslconfig.lua
new file mode 100644
index 00000000..931502b9
--- /dev/null
+++ b/util/sslconfig.lua
@@ -0,0 +1,118 @@
+-- util to easily merge multiple sets of LuaSec context options
+
+local type = type;
+local pairs = pairs;
+local rawset = rawset;
+local t_concat = table.concat;
+local t_insert = table.insert;
+local setmetatable = setmetatable;
+
+local _ENV = nil;
+
+local handlers = { };
+local finalisers = { };
+local id = function (v) return v end
+
+-- All "handlers" behave like extended rawset(table, key, value) with extra
+-- processing usually merging the new value with the old in some reasonable
+-- way
+-- If a field does not have a defined handler then a new value simply
+-- replaces the old.
+
+
+-- Convert either a list or a set into a special type of set where each
+-- item is either positive or negative in order for a later set of options
+-- to be able to remove options from this set by filtering out the negative ones
+function handlers.options(config, field, new)
+	local options = config[field] or { };
+	if type(new) ~= "table" then new = { new } end
+	for key, value in pairs(new) do
+		if value == true or value == false then
+			options[key] = value;
+		else -- list item
+			options[value] = true;
+		end
+	end
+	config[field] = options;
+end
+
+handlers.verifyext = handlers.options;
+
+-- finalisers take something produced by handlers and return what luasec
+-- expects it to be
+
+-- Produce a list of "positive" options from the set
+function finalisers.options(options)
+	local output = {};
+	for opt, enable in pairs(options) do
+		if enable then
+			output[#output+1] = opt;
+		end
+	end
+	return output;
+end
+
+finalisers.verifyext = finalisers.options;
+
+-- We allow ciphers to be a list
+
+function finalisers.ciphers(cipherlist)
+	if type(cipherlist) == "table" then
+		return t_concat(cipherlist, ":");
+	end
+	return cipherlist;
+end
+
+-- protocol = "x" should enable only that protocol
+-- protocol = "x+" should enable x and later versions
+
+local protocols = { "sslv2", "sslv3", "tlsv1", "tlsv1_1", "tlsv1_2" };
+for i = 1, #protocols do protocols[protocols[i] .. "+"] = i - 1; end
+
+-- this interacts with ssl.options as well to add no_x
+local function protocol(config)
+	local min_protocol = protocols[config.protocol];
+	if min_protocol then
+		config.protocol = "sslv23";
+		for i = 1, min_protocol do
+			t_insert(config.options, "no_"..protocols[i]);
+		end
+	end
+end
+
+-- Merge options from 'new' config into 'config'
+local function apply(config, new)
+	if type(new) == "table" then
+		for field, value in pairs(new) do
+			(handlers[field] or rawset)(config, field, value);
+		end
+	end
+end
+
+-- Finalize the config into the form LuaSec expects
+local function final(config)
+	local output = { };
+	for field, value in pairs(config) do
+		output[field] = (finalisers[field] or id)(value);
+	end
+	-- Need to handle protocols last because it adds to the options list
+	protocol(output);
+	return output;
+end
+
+local sslopts_mt = {
+	__index = {
+		apply = apply;
+		final = final;
+	};
+};
+
+local function new()
+	return setmetatable({options={}}, sslopts_mt);
+end
+
+return {
+	apply = apply;
+	final = final;
+	new = new;
+};