From mboxrd@z Thu Jan 1 00:00:00 1970 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 5D1EBC433EF for ; Wed, 9 Feb 2022 18:47:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240674AbiBISpp (ORCPT ); Wed, 9 Feb 2022 13:45:45 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240639AbiBISpS (ORCPT ); Wed, 9 Feb 2022 13:45:18 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3C407C014F38; Wed, 9 Feb 2022 10:43:02 -0800 (PST) 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 2291D60AF2; Wed, 9 Feb 2022 18:43:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EB52BC340EE; Wed, 9 Feb 2022 18:42:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1644432180; bh=Hoe3hbDIhOIeCzH4DhlqDkPDZL1ybNeNyJFFty6aEqE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oNKEWpjpcGaTgEYuWsTsUodZTITewLgCDFYZ7J86cMW95RvoosYO8NhugDxirIUQ0 FWQtHWLyrmraac1mkUefjhb2GFVbjqYSDPybUpKj0Fpiq8i1buIByNAjX0eDNPJcoL dUoK0LsqUvJwhS6a3DSwSgsH92b770rYbs71cTvZxfWAZIhYvN5HdwaxJKGpPyaUih 74ruyxNFXCjKY1JLb7uetoXg1o1ZNjyv/ig6B1PUgJb64N3G8iNH+ye0uvnGgcZAE3 aeZ7RaO738kZ6W4LMR3bqHMnUscB9AGv2Dr05TCEEQxL8znbMUKbhQrvMJ+/miBZnz kq4f4eHg/wCSA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Jason A. Donenfeld" , Dominik Brodowski , Sasha Levin , tytso@mit.edu Subject: [PATCH AUTOSEL 5.10 27/27] random: wake up /dev/random writers after zap Date: Wed, 9 Feb 2022 13:41:03 -0500 Message-Id: <20220209184103.47635-27-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220209184103.47635-1-sashal@kernel.org> References: <20220209184103.47635-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Jason A. Donenfeld" [ Upstream commit 042e293e16e3aa9794ce60c29f5b7b0c8170f933 ] When account() is called, and the amount of entropy dips below random_write_wakeup_bits, we wake up the random writers, so that they can write some more in. However, the RNDZAPENTCNT/RNDCLEARPOOL ioctl sets the entropy count to zero -- a potential reduction just like account() -- but does not unblock writers. This commit adds the missing logic to that ioctl to unblock waiting writers. Reviewed-by: Dominik Brodowski Signed-off-by: Jason A. Donenfeld Signed-off-by: Sasha Levin --- drivers/char/random.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index 5444206f35e22..5f541c9465598 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1987,7 +1987,10 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg) */ if (!capable(CAP_SYS_ADMIN)) return -EPERM; - input_pool.entropy_count = 0; + if (xchg(&input_pool.entropy_count, 0) && random_write_wakeup_bits) { + wake_up_interruptible(&random_write_wait); + kill_fasync(&fasync, SIGIO, POLL_OUT); + } return 0; case RNDRESEEDCRNG: if (!capable(CAP_SYS_ADMIN)) -- 2.34.1