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 X-Spam-Level: X-Spam-Status: No, score=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66036C4360F for ; Wed, 3 Apr 2019 12:17:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2F4A72084B for ; Wed, 3 Apr 2019 12:17:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=rasmusvillemoes.dk header.i=@rasmusvillemoes.dk header.b="PDel+T6c" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726263AbfDCMRo (ORCPT ); Wed, 3 Apr 2019 08:17:44 -0400 Received: from mail-lj1-f196.google.com ([209.85.208.196]:42996 "EHLO mail-lj1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726074AbfDCMRo (ORCPT ); Wed, 3 Apr 2019 08:17:44 -0400 Received: by mail-lj1-f196.google.com with SMTP id v22so9972846lje.9 for ; Wed, 03 Apr 2019 05:17:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rasmusvillemoes.dk; s=google; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=8yo9PlIGRvKMYjgwhQ0bYkMPLDCvIBBMPm5yOH2/BOc=; b=PDel+T6cl4UTjTboDO+bwMZn63ZZ66I8QVoIPBQiPDe4z0P9fudt0t/qUbLl0XXFnM jwYTlO+LcYJz5XXq/fE20iGtR8xvb4wiEL5WJQvfbm5KZNyPdzefXaBEtpvoZk8StlEC +tNd0sUvHxn0OwVl8VtXQAnqIX9jNKN7n4jH8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=8yo9PlIGRvKMYjgwhQ0bYkMPLDCvIBBMPm5yOH2/BOc=; b=hBeLf+FiOnrrZy4MVqrqXqJ2mfG1Nd6rC/nqqCsStSwuV6vgyNchOM8vBn9KKrrBpn j3s/9m4CZYbFF4UGMRQhA7fV5bp4ZVTSTwpck39sNs/ARRLLZ2/cjoF9G1WrGSsobnv1 v1unT+362vZT+rNiQ4sofLof/Xf/RPLOfqvsqZv4D8W5t3jnAjvrSplBn+eC5+jXLT7B G2OmB4N4YUM//0xLeZ2PNcDza0m8yDy/P2gbn6KKOFLdpHvwCjRh5ol0NMlvAX6SIWVH VuOD/xl/aZys8HNP1LjNx4jN3nCcVUsg7vw38GOaoAJTnifDo0n/tpwLzVA2Hw9tVZzO WQuQ== X-Gm-Message-State: APjAAAWNRfBFr4bjM5lukGhe/baPAZVlxoEWgKg4lXq8lLEgjYe1L8HU PViSQ8xheiwD1iJ+KQZgZxrNRgdEBd2p7CHm X-Google-Smtp-Source: APXvYqzxlah/cCjENnfGcq5nM/MQ6YpJjOKkKtKlKk+r6w7OepLqLZLPjvWHoWb0AM8w/tsSfqHJCw== X-Received: by 2002:a2e:9213:: with SMTP id k19mr20279197ljg.118.1554293861753; Wed, 03 Apr 2019 05:17:41 -0700 (PDT) Received: from [172.16.11.26] ([81.216.59.226]) by smtp.gmail.com with ESMTPSA id j14sm3182937lfb.18.2019.04.03.05.17.40 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 03 Apr 2019 05:17:40 -0700 (PDT) Subject: Re: [PATCH 1/5] lib: make bitmap_parselist_user() a wrapper on bitmap_parselist() To: Andy Shevchenko , Yury Norov Cc: Andrew Morton , Arnd Bergmann , Kees Cook , Matthew Wilcox , Tetsuo Handa , Mike Travis , Yury Norov , linux-kernel@vger.kernel.org References: <20190403044540.16322-1-ynorov@marvell.com> <20190403044540.16322-2-ynorov@marvell.com> <20190403111522.GP9224@smile.fi.intel.com> <20190403111745.GQ9224@smile.fi.intel.com> From: Rasmus Villemoes Message-ID: <8408fada-5fcc-9a45-9631-685505ed14f0@rasmusvillemoes.dk> Date: Wed, 3 Apr 2019 14:17:39 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190403111745.GQ9224@smile.fi.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/04/2019 13.17, Andy Shevchenko wrote: > On Wed, Apr 03, 2019 at 02:15:22PM +0300, Andy Shevchenko wrote: >> On Wed, Apr 03, 2019 at 07:45:36AM +0300, Yury Norov wrote: >>> Currently we parse user data byte after byte which leads to >>> overcomplification of parsing algorithm. The only user of >>> bitmap_parselist_user() is not performance-critical, and so we >>> can copy user data to kernel buffer and simply call >>> bitmap_parselist(). This rework lets us unify and simplify >>> bitmap_parselist() and bitmap_parselist_user(), which is done >>> in the following patch. >> >>> + buf = kmalloc(ulen + 1, GFP_KERNEL); >>> + if (!buf) >>> + return -ENOMEM; >>> + >>> + buf[ulen] = 0; >>> + >>> + ret = copy_from_user(buf, ubuf, ulen); >>> + if (ret) >>> + goto out; >> >> Why not memdup_user() ? > > Even more precisely (for strings) strndup_user(). > But the user buffer is not nul-terminated, i.e. it's not a string. What you want is memdup_user_nul() - take a length-delimited user buffer and turn it into a nul-terminated string in kernel memory. And yes, please use that. Rasmus