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.
local cache = require "util.cache";
describe("util.cache", function()
describe("#new()", function()
it("should work", function()
local c = cache.new(5);
local function expect_kv(key, value, actual_key, actual_value)
assert.are.equal(key, actual_key, "key incorrect");
assert.are.equal(value, actual_value, "value incorrect");
end
expect_kv(nil, nil, c:head());
expect_kv(nil, nil, c:tail());
assert.are.equal(c:count(), 0);
c:set("one", 1)
assert.are.equal(c:count(), 1);
expect_kv("one", 1, c:head());
expect_kv("one", 1, c:tail());
c:set("two", 2)
expect_kv("two", 2, c:head());
expect_kv("one", 1, c:tail());
c:set("three", 3)
expect_kv("three", 3, c:head());
expect_kv("one", 1, c:tail());
c:set("four", 4)
c:set("five", 5);
assert.are.equal(c:count(), 5);
expect_kv("five", 5, c:head());
expect_kv("one", 1, c:tail());
c:set("foo", nil);
assert.are.equal(c:count(), 5);
expect_kv("five", 5, c:head());
expect_kv("one", 1, c:tail());
assert.are.equal(c:get("one"), 1);
expect_kv("five", 5, c:head());
expect_kv("one", 1, c:tail());
assert.are.equal(c:get("two"), 2);
assert.are.equal(c:get("three"), 3);
assert.are.equal(c:get("four"), 4);
assert.are.equal(c:get("five"), 5);
assert.are.equal(c:get("foo"), nil);
assert.are.equal(c:get("bar"), nil);
c:set("six", 6);
assert.are.equal(c:count(), 5);
expect_kv("six", 6, c:head());
expect_kv("two", 2, c:tail());
assert.are.equal(c:get("one"), nil);
assert.are.equal(c:get("two"), 2);
assert.are.equal(c:get("three"), 3);
assert.are.equal(c:get("four"), 4);
assert.are.equal(c:get("five"), 5);
assert.are.equal(c:get("six"), 6);
c:set("three", nil);
assert.are.equal(c:count(), 4);
assert.are.equal(c:get("one"), nil);
assert.are.equal(c:get("two"), 2);
assert.are.equal(c:get("three"), nil);
assert.are.equal(c:get("four"), 4);
assert.are.equal(c:get("five"), 5);
assert.are.equal(c:get("six"), 6);
c:set("seven", 7);
assert.are.equal(c:count(), 5);
assert.are.equal(c:get("one"), nil);
assert.are.equal(c:get("two"), 2);
assert.are.equal(c:get("three"), nil);
assert.are.equal(c:get("four"), 4);
assert.are.equal(c:get("five"), 5);
assert.are.equal(c:get("six"), 6);
assert.are.equal(c:get("seven"), 7);
c:set("eight", 8);
assert.are.equal(c:count(), 5);
assert.are.equal(c:get("one"), nil);
assert.are.equal(c:get("two"), nil);
assert.are.equal(c:get("three"), nil);
assert.are.equal(c:get("four"), 4);
assert.are.equal(c:get("five"), 5);
assert.are.equal(c:get("six"), 6);
assert.are.equal(c:get("seven"), 7);
assert.are.equal(c:get("eight"), 8);
c:set("four", 4);
assert.are.equal(c:count(), 5);
assert.are.equal(c:get("one"), nil);
assert.are.equal(c:get("two"), nil);
assert.are.equal(c:get("three"), nil);
assert.are.equal(c:get("four"), 4);
assert.are.equal(c:get("five"), 5);
assert.are.equal(c:get("six"), 6);
assert.are.equal(c:get("seven"), 7);
assert.are.equal(c:get("eight"), 8);
c:set("nine", 9);
assert.are.equal(c:count(), 5);
assert.are.equal(c:get("one"), nil);
assert.are.equal(c:get("two"), nil);
assert.are.equal(c:get("three"), nil);
assert.are.equal(c:get("four"), 4);
assert.are.equal(c:get("five"), nil);
assert.are.equal(c:get("six"), 6);
assert.are.equal(c:get("seven"), 7);
assert.are.equal(c:get("eight"), 8);
assert.are.equal(c:get("nine"), 9);
do
local keys = { "nine", "four", "eight", "seven", "six" };
local values = { 9, 4, 8, 7, 6 };
local i = 0;
for k, v in c:items() do
i = i + 1;
assert.are.equal(k, keys[i]);
assert.are.equal(v, values[i]);
end
assert.are.equal(i, 5);
c:set("four", "2+2");
assert.are.equal(c:count(), 5);
assert.are.equal(c:get("one"), nil);
assert.are.equal(c:get("two"), nil);
assert.are.equal(c:get("three"), nil);
assert.are.equal(c:get("four"), "2+2");
assert.are.equal(c:get("five"), nil);
assert.are.equal(c:get("six"), 6);
assert.are.equal(c:get("seven"), 7);
assert.are.equal(c:get("eight"), 8);
assert.are.equal(c:get("nine"), 9);
end
do
local keys = { "four", "nine", "eight", "seven", "six" };
local values = { "2+2", 9, 8, 7, 6 };
local i = 0;
for k, v in c:items() do
i = i + 1;
assert.are.equal(k, keys[i]);
assert.are.equal(v, values[i]);
end
assert.are.equal(i, 5);
c:set("foo", nil);
assert.are.equal(c:count(), 5);
assert.are.equal(c:get("one"), nil);
assert.are.equal(c:get("two"), nil);
assert.are.equal(c:get("three"), nil);
assert.are.equal(c:get("four"), "2+2");
assert.are.equal(c:get("five"), nil);
assert.are.equal(c:get("six"), 6);
assert.are.equal(c:get("seven"), 7);
assert.are.equal(c:get("eight"), 8);
assert.are.equal(c:get("nine"), 9);
end
do
local keys = { "four", "nine", "eight", "seven", "six" };
local values = { "2+2", 9, 8, 7, 6 };
local i = 0;
for k, v in c:items() do
i = i + 1;
assert.are.equal(k, keys[i]);
assert.are.equal(v, values[i]);
end
assert.are.equal(i, 5);
c:set("four", nil);
assert.are.equal(c:get("one"), nil);
assert.are.equal(c:get("two"), nil);
assert.are.equal(c:get("three"), nil);
assert.are.equal(c:get("four"), nil);
assert.are.equal(c:get("five"), nil);
assert.are.equal(c:get("six"), 6);
assert.are.equal(c:get("seven"), 7);
assert.are.equal(c:get("eight"), 8);
assert.are.equal(c:get("nine"), 9);
end
do
local keys = { "nine", "eight", "seven", "six" };
local values = { 9, 8, 7, 6 };
local i = 0;
for k, v in c:items() do
i = i + 1;
assert.are.equal(k, keys[i]);
assert.are.equal(v, values[i]);
end
assert.are.equal(i, 4);
end
do
local evicted_key, evicted_value;
local c2 = cache.new(3, function (_key, _value)
evicted_key, evicted_value = _key, _value;
end);
local function set(k, v, should_evict_key, should_evict_value)
evicted_key, evicted_value = nil, nil;
c2:set(k, v);
assert.are.equal(evicted_key, should_evict_key);
assert.are.equal(evicted_value, should_evict_value);
end
set("a", 1)
set("a", 1)
set("a", 1)
set("a", 1)
set("a", 1)
set("b", 2)
set("c", 3)
set("b", 2)
set("d", 4, "a", 1)
set("e", 5, "c", 3)
end
do
local evicted_key, evicted_value;
local c3 = cache.new(1, function (_key, _value)
evicted_key, evicted_value = _key, _value;
if _key == "a" then
-- Sanity check for what we're evicting
assert.are.equal(_key, "a");
assert.are.equal(_value, 1);
-- We're going to block eviction of this key/value, so set to nil...
evicted_key, evicted_value = nil, nil;
-- Returning false to block eviction
return false
end
end);
local function set(k, v, should_evict_key, should_evict_value)
evicted_key, evicted_value = nil, nil;
local ret = c3:set(k, v);
assert.are.equal(evicted_key, should_evict_key);
assert.are.equal(evicted_value, should_evict_value);
return ret;
end
set("a", 1)
set("a", 1)
set("a", 1)
set("a", 1)
set("a", 1)
-- Our on_evict prevents "a" from being evicted, causing this to fail...
assert.are.equal(set("b", 2), false, "Failed to prevent eviction, or signal result");
expect_kv("a", 1, c3:head());
expect_kv("a", 1, c3:tail());
-- Check the final state is what we expect
assert.are.equal(c3:get("a"), 1);
assert.are.equal(c3:get("b"), nil);
assert.are.equal(c3:count(), 1);
end
local c4 = cache.new(3, false);
assert.are.equal(c4:set("a", 1), true);
assert.are.equal(c4:set("a", 1), true);
assert.are.equal(c4:set("a", 1), true);
assert.are.equal(c4:set("a", 1), true);
assert.are.equal(c4:set("b", 2), true);
assert.are.equal(c4:set("c", 3), true);
assert.are.equal(c4:set("d", 4), false);
assert.are.equal(c4:set("d", 4), false);
assert.are.equal(c4:set("d", 4), false);
expect_kv("c", 3, c4:head());
expect_kv("a", 1, c4:tail());
local c5 = cache.new(3, function (k, v) --luacheck: ignore 212/v
if k == "a" then
return nil;
elseif k == "b" then
return true;
end
return false;
end);
assert.are.equal(c5:set("a", 1), true);
assert.are.equal(c5:set("a", 1), true);
assert.are.equal(c5:set("a", 1), true);
assert.are.equal(c5:set("a", 1), true);
assert.are.equal(c5:set("b", 2), true);
assert.are.equal(c5:set("c", 3), true);
assert.are.equal(c5:set("d", 4), true); -- "a" evicted (cb returned nil)
assert.are.equal(c5:set("d", 4), true); -- nop
assert.are.equal(c5:set("d", 4), true); -- nop
assert.are.equal(c5:set("e", 5), true); -- "b" evicted (cb returned true)
assert.are.equal(c5:set("f", 6), false); -- "c" won't evict (cb returned false)
expect_kv("e", 5, c5:head());
expect_kv("c", 3, c5:tail());
end);
end);
end);