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 E495CCD13CF for ; Mon, 2 Sep 2024 06:31:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6FF6C8D007D; Mon, 2 Sep 2024 02:31:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6AEB38D0065; Mon, 2 Sep 2024 02:31:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 576EC8D007D; Mon, 2 Sep 2024 02:31:14 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 385CE8D0065 for ; Mon, 2 Sep 2024 02:31:14 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id D08B0A1958 for ; Mon, 2 Sep 2024 06:31:13 +0000 (UTC) X-FDA: 82518826026.13.7D581AF Received: from mail-pf1-f180.google.com (mail-pf1-f180.google.com [209.85.210.180]) by imf14.hostedemail.com (Postfix) with ESMTP id 037B0100002 for ; Mon, 2 Sep 2024 06:31:11 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=osandov-com.20230601.gappssmtp.com header.s=20230601 header.b=mjQEUeqN; spf=none (imf14.hostedemail.com: domain of osandov@osandov.com has no SPF policy when checking 209.85.210.180) smtp.mailfrom=osandov@osandov.com; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1725258624; a=rsa-sha256; cv=none; b=aJ4CCWE/jWSPYrE7otIHuYzvy5FQVqJzZUn/gi8DMeq04/6bAsu57A6GlWA/eZ0SWjUPnQ J4mVImakk3ODdTmGqOIXm7eoeaC0SYgUOkL7wk4wsh+/bZKijLJK+LCb1HHE/sx94UuIpK rPCgb+jxxzTybYld4HzYtf8PetK1T4A= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=osandov-com.20230601.gappssmtp.com header.s=20230601 header.b=mjQEUeqN; spf=none (imf14.hostedemail.com: domain of osandov@osandov.com has no SPF policy when checking 209.85.210.180) smtp.mailfrom=osandov@osandov.com; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1725258624; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=4QRHpO2u5pbpxFjPI4wQ+JqY+Z37bYljgBG+DFxhCvw=; b=OxLt9UcqrOYRDfbV8Kbu1UtlZpH2dcHINJjrl25YQ7VhrMSEhGGX5eFvNPw5ud/xnsHydw 9oqfoDHVVJyjQW/TkitZ20MKpKVGj5rVtltES81L7bnKGiFJowKW0vSL4d1vIJ7myNWAPa xRdu3KlF7ABBSZCtR99Nau1vrjHN1kE= Received: by mail-pf1-f180.google.com with SMTP id d2e1a72fcca58-7174a3baf92so72576b3a.1 for ; Sun, 01 Sep 2024 23:31:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=osandov-com.20230601.gappssmtp.com; s=20230601; t=1725258670; x=1725863470; darn=kvack.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=4QRHpO2u5pbpxFjPI4wQ+JqY+Z37bYljgBG+DFxhCvw=; b=mjQEUeqNKSMpLK6glyl49RQrJ4f/Loxv9M8sFcGU8NR2Qj9covdgtfw4I3EJF7fjv/ MFrRznRREL/L3q1ZnxEyEIK2mI0wfZVDGCwCCPlCRXQhtjnCUSlS615HYN6j9BIj0Rqg vkYYl+hTLQuzjsG0QyLEG51eSnFO53WDf0wCj2mfcFKxNJ7MxdqpMHZR+adBBVpYX/He 7VA956J1n0mi5DR8uhIP6B4GLpcl4E+9hYGMep1TDjN7yngFH00DHDfOkQrg/N3Bm8Ca ieBMnSLhw10h16/kw8MMxRMQgWT5kpywC0jpEA+uAS7Wll//BbGZxltyndErEoDtO6aB +ezg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1725258670; x=1725863470; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=4QRHpO2u5pbpxFjPI4wQ+JqY+Z37bYljgBG+DFxhCvw=; b=UarpBiRTKV7uWP079NZQ3D0G8ZunBAGQ/sfODb8HOb+do0EXeOsuRYyNle7Fs8+Gzx JPPWZeny0wXzpQRSIUuarlO6KqJm679kRWXx1f2jNzyQbTXWEbyKMMydeLxKkBudfsn0 O06NMDYu55QEjq+bmaJ0NLbWHECxCasx6b5/qmmTjVwNzi8eywC4Is9acdzpcAXwKBdP J14MacvXdWNvyi++8pIZD1owanWzVFUGJ0sP09woGf5rhUOcHGbcS/dBOEYXaKdrK2/X a0uHaPSdJKKm28VqJvCNgqRIqcEN7G1YtN4O8KuUfhah2YmZiv7GJxbxp4AdkBgWNBx0 Imfw== X-Gm-Message-State: AOJu0Yyxl2qVd95tzTgk5bjXW7S5rOrKmGytF/qIfy8bGtRjrvETHPSh bubTVASqevmJLQMBpnbFzdHO5UXKA+Kn7jdRMrspV6Wj6IIOY9TNKltM5V2MIeM= X-Google-Smtp-Source: AGHT+IEamVmuc71sTYPdHjFxuF/z2Kir18akAJnclZjSyzrG4uveb/oGnmnZ8wSmLeO97ZW2P5fb1A== X-Received: by 2002:a17:902:da86:b0:1fb:1ae6:6aa7 with SMTP id d9443c01a7336-2052750795amr58817315ad.3.1725258670426; Sun, 01 Sep 2024 23:31:10 -0700 (PDT) Received: from telecaster ([2601:602:8980:9170::901f]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-20515542350sm59747515ad.213.2024.09.01.23.31.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 01 Sep 2024 23:31:09 -0700 (PDT) Date: Sun, 1 Sep 2024 23:31:08 -0700 From: Omar Sandoval To: Christophe Leroy Cc: linux-mm@kvack.org, Andrew Morton , Christoph Hellwig , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-um@lists.infradead.org, kernel-team@fb.com Subject: Re: [PATCH 0/2] mm: make copy_to_kernel_nofault() not fault on user addresses Message-ID: References: <5fa50d78-6764-4f99-87b3-7bd7edbeea5a@csgroup.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5fa50d78-6764-4f99-87b3-7bd7edbeea5a@csgroup.eu> X-Stat-Signature: 1r38ykt99up6zh7p4eouxtgpxkwoshqq X-Rspamd-Queue-Id: 037B0100002 X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1725258671-251441 X-HE-Meta: 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 e8GBeRBb 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.002045, 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 Mon, Sep 02, 2024 at 08:19:33AM +0200, Christophe Leroy wrote: > > > Le 02/09/2024 à 07:31, Omar Sandoval a écrit : > > [Vous ne recevez pas souvent de courriers de osandov@osandov.com. Découvrez pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification ] > > > > From: Omar Sandoval > > > > Hi, > > > > I hit a case where copy_to_kernel_nofault() will fault (lol): if the > > destination address is in userspace and x86 Supervisor Mode Access > > Prevention is enabled. Patch 2 has the details and the fix. Patch 1 > > renames a helper function so that its use in patch 2 makes more sense. > > If the rename is too intrusive, I can drop it. > > The name of the function is "copy_to_kernel". If the destination is a user > address, it is not a copy to kernel but a copy to user and you already have > the function copy_to_user() for that. copy_to_user() properly handles SMAP. I'm not trying to copy to user. I am (well, KDB is) trying to copy to an arbitrary address, and I want it to return an error instead of crashing if the address is not a valid kernel address. As far as I can tell, that is the whole point of copy_to_kernel_nofault(). Thanks, Omar