Use a securely seeded global PRNG for the VM.

It's not 2005 anymore.

1 files changed, 24 insertions, 0 deletions

diff --git a/src/lj_prng.h b/src/lj_prng.h
new file mode 100644
index 00000000..40c34a71
--- /dev/null
+++ b/src/lj_prng.h
@@ -0,0 +1,24 @@
+/*
+** Pseudo-random number generation.
+** Copyright (C) 2005-2020 Mike Pall. See Copyright Notice in luajit.h
+*/
+
+#ifndef _LJ_PRNG_H
+#define _LJ_PRNG_H
+
+#include "lj_def.h"
+
+LJ_FUNC int LJ_FASTCALL lj_prng_seed_secure(PRNGState *rs);
+LJ_FUNC uint64_t LJ_FASTCALL lj_prng_u64(PRNGState *rs);
+LJ_FUNC uint64_t LJ_FASTCALL lj_prng_u64d(PRNGState *rs);
+
+/* This is just the precomputed result of lib_math.c:random_seed(rs, 0.0). */
+static LJ_AINLINE void lj_prng_seed_fixed(PRNGState *rs)
+{
+  rs->u[0] = U64x(a0d27757,0a345b8c);
+  rs->u[1] = U64x(764a296c,5d4aa64f);
+  rs->u[2] = U64x(51220704,070adeaa);
+  rs->u[3] = U64x(2a2717b5,a7b7b927);
+}
+
+#endif