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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2ED8EC48BF6 for ; Mon, 26 Feb 2024 10:39:38 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B55B580008; Mon, 26 Feb 2024 05:39:37 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B056B94002C; Mon, 26 Feb 2024 05:39:37 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9F46B80008; Mon, 26 Feb 2024 05:39:37 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 8D9E894002C for ; Mon, 26 Feb 2024 05:39:37 -0500 (EST) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 35A3E16076D for ; Mon, 26 Feb 2024 10:39:37 +0000 (UTC) X-FDA: 81833608794.27.B5DBE3F Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf03.hostedemail.com (Postfix) with ESMTP id B38EA20019 for ; Mon, 26 Feb 2024 10:39:35 +0000 (UTC) Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=WfutgURm; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf03.hostedemail.com: domain of jikos@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=jikos@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1708943975; 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-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=enAnnPs6vMcqMh2X6nIOdI0rWuPKZvZyHGCVSGS0Erc=; b=XvShDvOEJ/+2wUd0Z3yYH1qNYMDr/TFr4kxKWoGkjcEyYwXhOEL24Nipl4rw9LeT6f4ZnE E32phd0+g9gmFYQ9QLr3rlXXe6z1TthekxVSkHJKln7pwCFAGueNYK+RHAg5OYTq5815ZP zg3tTH044/lebmV/rqkzCQIKwJjsljQ= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=WfutgURm; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf03.hostedemail.com: domain of jikos@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=jikos@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1708943975; a=rsa-sha256; cv=none; b=mr2CzXSfHTLVI775wOw6c+lg3hDP0VqsuG3ZT08rw8I3fSwy50vGy4HG01htkANNxkTQcz V1QWjdMmWCZ7kX3ETTStFwfAJ9YEMFGI04CFEjqA0CzVNAkevEPKWaS8CIRb1AFxjWZPmJ hS9CBb9CHgu8BhvVEyvVbyQJzHFQEoc= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id A775160BA9; Mon, 26 Feb 2024 10:39:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C8C3DC433C7; Mon, 26 Feb 2024 10:39:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708943974; bh=ymjcFen8c3Su6bcKnRhsOkKT7wLiavklUN50no/AaHQ=; h=Date:From:To:cc:Subject:In-Reply-To:References:From; b=WfutgURm5TLAIvDzJD7MQrGOiOzovl+SSrWQDpL4BQZXqKXSlQ2C9l6cELAoAMBEq vdMEAelQUFi/VxzMO6RrmQAmEQK39mArk2ZgicrtiN7neDkvZI8bBAbAiOiXh9rn5v YRvqot7ee5G9BMdNI//SqP2QdML0e7tUw6dL1dQ2UbtHd4V0JqbCAca/IoBvMG3E7A q4l+a4VZS9iqKGPq5Hox7Ql+vxXdi8fiT6iUksgDB77c1408r/w2On0Q6QUCktvl6P umNGMDfpge25hvRiJ/pqUHobDyJpqvIhSyUKPC9rdtULwBYLJTcd/68H75Kv1+g69e mKgW5FtuQO6mw== Date: Mon, 26 Feb 2024 11:39:35 +0100 (CET) From: Jiri Kosina To: Kees Cook cc: y0un9n132@gmail.com, Geert Uytterhoeven , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Peter Zijlstra , Qi Zheng , Alexandre Ghiti , x86@kernel.org, Al Viro , Christian Brauner , Jan Kara , Eric Biederman , Christophe Leroy , Josh Poimboeuf , "Kirill A. Shutemov" , Rick Edgecombe , Brian Gerst , Bjorn Helgaas , Tony Battersby , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH 1/2] x86: Increase brk randomness entropy on x86_64 In-Reply-To: <20240217062545.1631668-1-keescook@chromium.org> Message-ID: References: <20240217062035.work.493-kees@kernel.org> <20240217062545.1631668-1-keescook@chromium.org> User-Agent: Alpine 2.21 (LSU 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspamd-Queue-Id: B38EA20019 X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: 5ih8etqpfktjupc6kkr1drremmy1819w X-HE-Tag: 1708943975-64709 X-HE-Meta: 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 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: List-Subscribe: List-Unsubscribe: On Fri, 16 Feb 2024, Kees Cook wrote: > In commit c1d171a00294 ("x86: randomize brk"), arch_randomize_brk() was > defined to use a 32MB range (13 bits of entropy), but was never increased > when moving to 64-bit. The default arch_randomize_brk() uses 32MB for > 32-bit tasks, and 1GB (18 bits of entropy) for 64-bit tasks. Update > x86_64 to match the entropy used by arm64 and other 64-bit architectures. > > Reported-by: y0un9n132@gmail.com > Closes: https://lore.kernel.org/linux-hardening/CA+2EKTVLvc8hDZc+2Yhwmus=dzOUG5E4gV7ayCbu0MPJTZzWkw@mail.gmail.com/ > Signed-off-by: Kees Cook Wow, this is a pretty aged code indeed. Acked-by: Jiri Kosina Thanks, -- Jiri Kosina SUSE Labs