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.

#ifndef _POSIX_C_SOURCE
#define _POSIX_C_SOURCE 199309L
#endif

#include <time.h>
#include <lua.h>

lua_Number tv2number(struct timespec *tv) {
	return tv->tv_sec + tv->tv_nsec * 1e-9;
}

int lc_time_realtime(lua_State *L) {
	struct timespec t;
	clock_gettime(CLOCK_REALTIME, &t);
	lua_pushnumber(L, tv2number(&t));
	return 1;
}

int lc_time_monotonic(lua_State *L) {
	struct timespec t;
	clock_gettime(CLOCK_MONOTONIC, &t);
	lua_pushnumber(L, tv2number(&t));
	return 1;
}

int luaopen_util_time(lua_State *L) {
	lua_createtable(L, 0, 2);
	{
		lua_pushcfunction(L, lc_time_realtime);
		lua_setfield(L, -2, "now");
		lua_pushcfunction(L, lc_time_monotonic);
		lua_setfield(L, -2, "monotonic");
	}
	return 1;
}