mirage-crypto-rng-lwt: always feed the default generator

rng/entropy.ml

@@ -132,14 +132,16 @@ let interrupt_hook () =
     buf
 
 let timer_accumulator g =
-  let `Acc handle = Rng.accumulate (Some g) ~source:(source_id `Timer) in
+  let g = match g with None -> Some (Rng.default_generator ()) | Some g -> Some g in
+  let `Acc handle = Rng.accumulate g ~source:(source_id `Timer) in
   let hook = interrupt_hook () in
   add_source `Timer;
   (fun () -> handle (hook ()))
 
 let feed_pools g source f =
-  let `Acc handle = Rng.accumulate (Some g) ~source:(source_id source) in
-  for _i = 0 to pred (Rng.pools (Some g)) do
+  let g = match g with None -> Some (Rng.default_generator ()) | Some g -> Some g in
+  let `Acc handle = Rng.accumulate g ~source:(source_id source) in
+  for _i = 0 to pred (Rng.pools g) do
     let cs = f () in
     handle cs
   done

rng/lwt/mirage_crypto_rng_lwt.ml

@@ -8,22 +8,22 @@ let periodic f delta =
       in
       one ())
 
-let getrandom_task g delta =
+let getrandom_task delta =
   let task () =
     let per_pool = 8 in
-    let size = per_pool * pools (Some g) in
+    let size = per_pool * pools None in
     let random = Mirage_crypto_rng_unix.getrandom size in
     let idx = ref 0 in
     let f () =
       incr idx;
       Cstruct.sub random (per_pool * (pred !idx)) per_pool
     in
-    Entropy.feed_pools g `Getrandom f
+    Entropy.feed_pools None `Getrandom f
   in
   periodic task delta
 
-let rdrand_task g delta =
-  let task () = Entropy.cpu_rng g in
+let rdrand_task delta =
+  let task () = Entropy.cpu_rng None in
   periodic task delta
 
 let running = ref false
@@ -53,7 +53,7 @@ let initialize ?(sleep = Duration.of_sec 1) () =
   Entropy.add_source `Getrandom;
   let rng = create ~seed ~time:Mtime_clock.elapsed_ns (module Fortuna) in
   set_default_generator rng;
-  rdrand_task rng sleep;
-  getrandom_task rng (Int64.mul sleep 10L);
-  let _ = Lwt_main.Enter_iter_hooks.add_first (Entropy.timer_accumulator rng) in
+  rdrand_task sleep;
+  getrandom_task (Int64.mul sleep 10L);
+  let _ = Lwt_main.Enter_iter_hooks.add_first (Entropy.timer_accumulator None) in
   Lwt.return_unit

rng/mirage/mirage_crypto_rng_mirage.ml

@@ -61,8 +61,8 @@ module Make (T : Mirage_time.S) (M : Mirage_clock.MCLOCK) = struct
       in
       let rng = create ?g ~seed ~time:M.elapsed_ns rng in
       set_default_generator rng;
-      rdrand_task rng sleep;
-      Mirage_runtime.at_enter_iter (Entropy.timer_accumulator rng);
+      rdrand_task (Some rng) sleep;
+      Mirage_runtime.at_enter_iter (Entropy.timer_accumulator (Some rng));
       Lwt.return_unit
     end
 end

rng/mirage_crypto_rng.mli

@@ -218,17 +218,17 @@ module Entropy : sig
   (** [interrupt_hook ()] collects the lower 4 bytes from [rdtsc], to be
       used for entropy collection in the event loop. *)
 
-  val timer_accumulator : g -> unit -> unit
+  val timer_accumulator : g option -> unit -> unit
   (** [timer_accumulator g] is the accumulator for the [`Timer] source,
       applying {!interrupt_hook} on each call. *)
 
   (** {1 Periodic pulled sources} *)
 
-  val feed_pools : g -> source -> (unit -> Cstruct.t) -> unit
+  val feed_pools : g option -> source -> (unit -> Cstruct.t) -> unit
   (** [feed_pools g source f] feeds all pools of [g] using [source] by executing
       [f] for each pool. *)
 
-  val cpu_rng : g -> unit
+  val cpu_rng : g option -> unit
   (** [cpu_rng g] uses the CPU RNG (rdrand or rdseed) to feed all pools
       of [g]. *)