From 64311899db7c455c5f07f7ff30c5a52c50b8fbae Mon Sep 17 00:00:00 2001
From: Alexander Kjeldaas <ak@formalprivacy.com>
Date: Wed, 21 Aug 2013 11:12:04 +0200
Subject: [PATCH] Don't let rngd read /dev/tpm0.

Only one process can interact with the TPM module and
that process should be tcsd.  The tpm_rng kernel module
should instead be loaded and /dev/hwrnd be used to
read the TPM random generator.
Also, log which random generator devices are used by
rngd on startup.
---
 nixos/modules/security/rngd.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/nixos/modules/security/rngd.nix b/nixos/modules/security/rngd.nix
index c31e57e6f6f..c47c1b2a67e 100644
--- a/nixos/modules/security/rngd.nix
+++ b/nixos/modules/security/rngd.nix
@@ -30,7 +30,7 @@ with lib;
 
       description = "Hardware RNG Entropy Gatherer Daemon";
 
-      serviceConfig.ExecStart = "${pkgs.rng_tools}/sbin/rngd -f";
+      serviceConfig.ExecStart = "${pkgs.rng_tools}/sbin/rngd -f -v --no-tpm=1";
 
       restartTriggers = [ pkgs.rng_tools ];
     };