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 2A6D6C32771 for ; Mon, 26 Sep 2022 21:32:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230230AbiIZVb6 (ORCPT ); Mon, 26 Sep 2022 17:31:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60358 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230096AbiIZVbu (ORCPT ); Mon, 26 Sep 2022 17:31:50 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0BB27391D for ; Mon, 26 Sep 2022 14:31:49 -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 ams.source.kernel.org (Postfix) with ESMTPS id 70E9AB81133 for ; Mon, 26 Sep 2022 21:31:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75A9EC433C1; Mon, 26 Sep 2022 21:31:46 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="ZejhL1fX" 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 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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) -- 2.37.3