From patchwork Mon Sep 26 21:31:30 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: 12989431 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id D04F0C07E9D for ; Mon, 26 Sep 2022 21:31:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4215F8E0088; Mon, 26 Sep 2022 17:31:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3D0B38E0066; Mon, 26 Sep 2022 17:31:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2713D8E0088; Mon, 26 Sep 2022 17:31:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 17FFE8E0066 for ; Mon, 26 Sep 2022 17:31:49 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id E2BD5160386 for ; Mon, 26 Sep 2022 21:31:48 +0000 (UTC) X-FDA: 79955533896.23.6B8FE91 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf24.hostedemail.com (Postfix) with ESMTP id 90B79180007 for ; Mon, 26 Sep 2022 21:31:48 +0000 (UTC) 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 CE2606145A; Mon, 26 Sep 2022 21:31:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75A9EC433C1; Mon, 26 Sep 2022 21:31:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1664227905; 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: in-reply-to:in-reply-to:references:references; bh=JLbf48vjMlZ56ruPBS9/QkT83yj7vuavaEds8C6XntY=; b=ZejhL1fXQ/v8Qg/iK+oOm7uXWm2BzU4H34s3VE+vjpIghtIo61Co1OU/kvkIwXpZREMKNi w0qUJE8VoDmqFEd+4H/uXVHWsfgPOwG54ULNfvRuZ0U3LI/7o/szg3J9bALMa3Z/z6j9gs 80hQNP19vXnYYd6MKvG+WW8jNxloAuY= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 0b02cf89 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Mon, 26 Sep 2022 21:31:44 +0000 (UTC) From: "Jason A. Donenfeld" To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, kasan-dev@googlegroups.com Cc: "Jason A. Donenfeld" , Alexander Potapenko , Dmitry Vyukov , Andrew Morton , Marco Elver Subject: [PATCH v2 2/2] kfence: use better stack hash seed Date: Mon, 26 Sep 2022 23:31:30 +0200 Message-Id: <20220926213130.1508261-2-Jason@zx2c4.com> In-Reply-To: <20220926213130.1508261-1-Jason@zx2c4.com> References: <20220926213130.1508261-1-Jason@zx2c4.com> MIME-Version: 1.0 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1664227908; a=rsa-sha256; cv=none; b=HmYEXyUyIR4b9zX2XmKwBbKqfBbtgtuo0hKuy1s9BVd79a+Mm+pfnGHiZ8mXB/6BW6c0p1 h/qrBO4m/oTpk8Fn+jXkwZTi+R5aA7yVk0fjeGCERgF+6evhfwOscmWuK3L03d4dQxV50k CNJ2M/J48KeSwt1MdBWDqqX3cn4cUls= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=zx2c4.com header.s=20210105 header.b=ZejhL1fX; dmarc=pass (policy=quarantine) header.from=zx2c4.com; spf=pass (imf24.hostedemail.com: domain of "SRS0=WzR3=Z5=zx2c4.com=Jason@kernel.org" designates 139.178.84.217 as permitted sender) smtp.mailfrom="SRS0=WzR3=Z5=zx2c4.com=Jason@kernel.org" ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1664227908; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=JLbf48vjMlZ56ruPBS9/QkT83yj7vuavaEds8C6XntY=; b=NeGESzuI+DN3bm3P2dMB+78PD/M19RJAx2mttMYU+nyMrUUO+4+kWiR0er8lx/yTPnblXV UO5xqoVEvksmorIv1Kn3j1DTZso3t9NFITeJD2pdw2e/Gdvx53zQD+vD0ktQnXrI7CpGRC m4v1tsS1n2s9aLowa+ZLr+ep+Xy3K+c= X-Stat-Signature: fh8kmi6r6qzyd9b36tq45pzq1nz5n4wf X-Rspam-User: X-Rspamd-Server: rspam04 Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=zx2c4.com header.s=20210105 header.b=ZejhL1fX; dmarc=pass (policy=quarantine) header.from=zx2c4.com; spf=pass (imf24.hostedemail.com: domain of "SRS0=WzR3=Z5=zx2c4.com=Jason@kernel.org" designates 139.178.84.217 as permitted sender) smtp.mailfrom="SRS0=WzR3=Z5=zx2c4.com=Jason@kernel.org" X-Rspamd-Queue-Id: 90B79180007 X-HE-Tag: 1664227908-906733 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: As of the prior commit, the RNG will have incorporated both a cycle counter value and RDRAND, in addition to various other environmental noise. Therefore, using get_random_u32() will supply a stronger seed than simply using random_get_entropy(). N.B.: random_get_entropy() should be considered an internal API of random.c and not generally consumed. Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: Andrew Morton Reviewed-by: Marco Elver Signed-off-by: Jason A. Donenfeld --- mm/kfence/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/kfence/core.c b/mm/kfence/core.c index c252081b11df..239b1b4b094f 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -864,7 +864,7 @@ static void kfence_init_enable(void) void __init kfence_init(void) { - stack_hash_seed = (u32)random_get_entropy(); + stack_hash_seed = get_random_u32(); /* Setting kfence_sample_interval to 0 on boot disables KFENCE. */ if (!kfence_sample_interval)