Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760585AbaGEFfe (ORCPT ); Sat, 5 Jul 2014 01:35:34 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38777 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760453AbaGEFfc (ORCPT ); Sat, 5 Jul 2014 01:35:32 -0400 From: Amit Shah To: linux-kernel@vger.kernel.org Cc: Virtualization List , Rusty Russell , herbert@gondor.apana.org.au, keescook@chromium.org, jason@lakedaemon.net, Amit Shah , Subject: [PATCH v2 1/2] hwrng: fetch randomness only after device init Date: Sat, 5 Jul 2014 11:04:52 +0530 Message-Id: <515a12ecc5fca5452bf0bfda4d54546d8fb5829c.1404538109.git.amit.shah@redhat.com> In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit d9e7972619334 "hwrng: add randomness to system from rng sources" added a call to rng_get_data() from the hwrng_register() function. However, some rng devices need initialization before data can be read from them. This commit makes the call to rng_get_data() depend on no init fn pointer being registered by the device. If an init function is registered, this call is made after device init. CC: Kees Cook CC: Jason Cooper CC: Herbert Xu CC: # For v3.15+ Signed-off-by: Amit Shah --- drivers/char/hw_random/core.c | 31 +++++++++++++++++++++++++------ 1 file changed, 25 insertions(+), 6 deletions(-) diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index 334601c..df95e2f 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -55,16 +55,37 @@ static DEFINE_MUTEX(rng_mutex); static int data_avail; static u8 *rng_buffer; +static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size, + int wait); + static size_t rng_buffer_size(void) { return SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES; } +static void add_early_randomness(struct hwrng *rng) +{ + unsigned char bytes[16]; + int bytes_read; + + bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1); + if (bytes_read > 0) + add_device_randomness(bytes, bytes_read); +} + static inline int hwrng_init(struct hwrng *rng) { + int ret; + if (!rng->init) return 0; - return rng->init(rng); + + ret = rng->init(rng); + if (ret) + return ret; + + add_early_randomness(rng); + return ret; } static inline void hwrng_cleanup(struct hwrng *rng) @@ -304,8 +325,6 @@ int hwrng_register(struct hwrng *rng) { 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)) @@ -347,9 +366,9 @@ 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); + if (!rng->init) + add_early_randomness(rng); + out_unlock: mutex_unlock(&rng_mutex); out: -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/