From patchwork Fri Aug 5 15:08:14 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephan Mueller X-Patchwork-Id: 9265503 X-Patchwork-Delegate: kvalo@adurom.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1DE1A60760 for ; Fri, 5 Aug 2016 15:08:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0EC6328426 for ; Fri, 5 Aug 2016 15:08:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 032FB28454; Fri, 5 Aug 2016 15:08:42 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8012F28426 for ; Fri, 5 Aug 2016 15:08:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759931AbcHEPIY (ORCPT ); Fri, 5 Aug 2016 11:08:24 -0400 Received: from mail.eperm.de ([89.247.134.16]:34042 "EHLO mail.eperm.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759865AbcHEPIW (ORCPT ); Fri, 5 Aug 2016 11:08:22 -0400 Received: from positron.chronox.de (mail.eperm.de [89.247.134.16]) by mail.eperm.de (Postfix) with ESMTPA id 4C2C918149CA; Fri, 5 Aug 2016 17:08:19 +0200 (CEST) From: Stephan Mueller To: Ted Tso , herbert@gondor.apana.org.au Cc: linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, ath9k-devel@qca.qualcomm.com, linux-wireless@vger.kernel.org, ath9k-devel@lists.ath9k.org, Kalle Valo Subject: [RFC][PATCH] RANDOM: ATH9K RNG delivers zero bits of entropy Date: Fri, 05 Aug 2016 17:08:14 +0200 Message-ID: <34197429.2CvoIfft9B@positron.chronox.de> User-Agent: KMail/5.2.3 (Linux/4.6.4-301.fc24.x86_64; KDE/5.24.0; x86_64; ; ) MIME-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Hi Ted, Herbert, I sent a question to the ATH9K RNG some time ago to the developers. See https://www.mail-archive.com/linux-crypto@vger.kernel.org/msg19115.html I have not yet received a word and I think this issue should be resolved. Thanks Stephan ---8<--- The ATH9K driver implements an RNG which is completely bypassing the standard Linux HW generator logic. The RNG may or may not deliver entropy. Considering the conservative approach in treating entropy with respect to non-auditable sources, this patch changes the delivered entropy value to zero. The RNG still feeds data into the input_pool but it is assumed to have no entropy. When the ATH9K RNG changes to use the HW RNG framework, it may re-enable the entropy estimation considering that a user can change that value at boot and runtime. Signed-off-by: Stephan Mueller Reviewed-by: Jason Cooper --- drivers/net/wireless/ath/ath9k/rng.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/net/wireless/ath/ath9k/rng.c b/drivers/net/wireless/ath/ath9k/rng.c index d38e50f..d63dc48 100644 --- a/drivers/net/wireless/ath/ath9k/rng.c +++ b/drivers/net/wireless/ath/ath9k/rng.c @@ -92,8 +92,7 @@ static int ath9k_rng_kthread(void *data) fail_stats = 0; /* sleep until entropy bits under write_wakeup_threshold */ - add_hwgenerator_randomness((void *)rng_buf, bytes_read, - ATH9K_RNG_ENTROPY(bytes_read)); + add_hwgenerator_randomness((void *)rng_buf, bytes_read, 0); } kfree(rng_buf);