From patchwork Tue Sep 20 14:14:38 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Jason A. Donenfeld" X-Patchwork-Id: 608029 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ED0F0C6FA8E for ; Tue, 20 Sep 2022 14:17:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231770AbiITORu (ORCPT ); Tue, 20 Sep 2022 10:17:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58736 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231580AbiITORZ (ORCPT ); Tue, 20 Sep 2022 10:17:25 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B0D185723B; Tue, 20 Sep 2022 07:14:51 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7B0F6622C9; Tue, 20 Sep 2022 14:14:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 573DBC433D6; Tue, 20 Sep 2022 14:14:49 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="Qt6+LjC5" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1663683287; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=xGcIeiqeQ+HS0QuciXX8z8BYA5ktdXUWt1D1mDhVW+s=; b=Qt6+LjC5kuokCGDGfgat4875HqXzeIURqazycms/NKkiX8SYTZHrVXV45XWn5D8ygnEvhW AHcJvWyjE1gNwF1zKKyQN+uee5HrlRYn1A5qChtKBQHFELsXB12LiBs2jxElD0pPILKVOM z1PmnADb8NGYvEiVlxLUo8FWId9DMEQ= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 2e2f7f43 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Tue, 20 Sep 2022 14:14:47 +0000 (UTC) From: "Jason A. Donenfeld" To: linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org Cc: "Jason A. Donenfeld" , Dominik Brodowski , Herbert Xu Subject: [PATCH] random: throttle hwrng writes if no entropy is credited Date: Tue, 20 Sep 2022 16:14:38 +0200 Message-Id: <20220920141438.2782446-1-Jason@zx2c4.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org This value is currently never set to zero, because the hwrng thread only runs if it's going to be non-zero. This is an oversight, however, that Dominik is working on fixing. In preparation for this, and so that there's less coordination required between my tree and Herbert's, make this currently useless, but not harmful, change here now, in hopes that Dominik can make the corresponding change in the hwrng core later. Cc: Dominik Brodowski Cc: Herbert Xu Signed-off-by: Jason A. Donenfeld --- drivers/char/random.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index 16e0c5f6cf2f..520a385c7dab 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -865,9 +865,9 @@ void add_hwgenerator_randomness(const void *buf, size_t len, size_t entropy) /* * Throttle writing to once every reseed interval, unless we're not yet - * initialized. + * initialized or no entropy is credited. */ - if (!kthread_should_stop() && crng_ready()) + if (!kthread_should_stop() && (crng_ready() || !entropy)) schedule_timeout_interruptible(crng_reseed_interval()); } EXPORT_SYMBOL_GPL(add_hwgenerator_randomness);