From: Kees Cook Subject: [PATCH][RESEND 3] hwrng: add randomness to system from rng sources Date: Mon, 3 Mar 2014 15:51:48 -0800 Message-ID: <20140303235148.GA7601@www.outflux.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Matt Mackall , Herbert Xu , Rusty Russell , Satoru Takeuchi , linux-crypto@vger.kernel.org, "Theodore Ts'o" , Andrew Morton To: linux-kernel@vger.kernel.org Return-path: Received: from smtp.outflux.net ([198.145.64.163]:54986 "EHLO smtp.outflux.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755248AbaCCXwF (ORCPT ); Mon, 3 Mar 2014 18:52:05 -0500 Content-Disposition: inline Sender: linux-crypto-owner@vger.kernel.org List-ID: When bringing a new RNG source online, it seems like it would make sense to use some of its bytes to make the system entropy pool more random, as done with all sorts of other devices that contain per-device or per-boot differences. Signed-off-by: Kees Cook --- drivers/char/hw_random/core.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index a0f7724852eb..6e5bb68a708c 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -41,6 +41,7 @@ #include #include #include +#include #include @@ -305,6 +306,8 @@ int hwrng_register(struct hwrng *rng) int must_register_misc; int err = -EINVAL; struct hwrng *old_rng, *tmp; + unsigned char bytes[16]; + int bytes_read; if (rng->name == NULL || (rng->data_read == NULL && rng->read == NULL)) @@ -348,6 +351,10 @@ int hwrng_register(struct hwrng *rng) } INIT_LIST_HEAD(&rng->list); list_add_tail(&rng->list, &rng_list); + + bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1); + if (bytes_read > 0) + add_device_randomness(bytes, bytes_read); out_unlock: mutex_unlock(&rng_mutex); out: -- 1.7.9.5 -- Kees Cook Chrome OS Security