From patchwork Mon Jun 24 14:32:52 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Konovalov X-Patchwork-Id: 11013449 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 71C76924 for ; Mon, 24 Jun 2019 14:34:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6135F28C00 for ; Mon, 24 Jun 2019 14:34:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 545AF28BFA; Mon, 24 Jun 2019 14:34:42 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, USER_IN_DEF_DKIM_WL autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EF48C28C07 for ; Mon, 24 Jun 2019 14:34:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729217AbfFXOel (ORCPT ); Mon, 24 Jun 2019 10:34:41 -0400 Received: from mail-qt1-f201.google.com ([209.85.160.201]:56776 "EHLO mail-qt1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729222AbfFXOd1 (ORCPT ); Mon, 24 Jun 2019 10:33:27 -0400 Received: by mail-qt1-f201.google.com with SMTP id p43so17108737qtk.23 for ; Mon, 24 Jun 2019 07:33:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=hgUbj0aIma7FN/fDppNoJ1F9osla3F1YuX2112+Mp8s=; b=XScBtinbiUGDniM5VWwPkGG4/4TOXpRMgLEipRA38wBRqrcXcDq9jBk/0BRZ6x9hlI V9LUyuozhqT/IxEnIqdvY3TfW2BBFmFPeZMV6/kHE3QjS3QjydQyEBZrtxP0iPkgc0Lq Fl63uCJcNPhGHDYzX4eXyVr2le0SZJjeeiUUJ6M7ZIcaEAu7j+hLiu/GnMRfjOmk9l2j 73WehpBOM1MSylhUeiF0hVgN+PDN+5kZdcFg4wO/LJNJCaEb2km52xgKxYMc9FCtyBPh HEL+2jGVAoHMOTxdl5nV9rz2oXMXpuOjUoFsub2nzlRgfcoGoFmp1CkWMhgLIpXXStyF WB2w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=hgUbj0aIma7FN/fDppNoJ1F9osla3F1YuX2112+Mp8s=; b=nVZc4KRMxokUuUW6MyrI94YPdLDYjb7mVSGvcondc+vRC8Sd+AbIYHLU5u0EjwzScC iG7vCLWTF8osfZ+2+lddFGKHFTV+tweNG8vhnuj1F5ZGonbZvAzaHK0LufOxzN5KCtnW zO6f27vA8FM3JZkZvslVeSrThi+IYcsrlHu2RSzJFhmpwfB02Vr0ENRaI19VwT+mYvLM Bho4uI4V8ZQ0e9/pYroLSE8mpn8sTkfNbmNj8dikkELbtKKHDE5B7A2GYhktWqXE9FcY Cc86tLp8Lhzj/owJbiJWiKtnMlQY5UJgb5/iYLYOw4hOLVRutBGV/qfv2HL1kO0yOTSQ NyrQ== X-Gm-Message-State: APjAAAVd6xGOAlWnwrJItS27+sD+JoQrUT9xavhlaX2ZN2/2pYbQSp9e DILI2a9lih5Xvt0tMGpo3TcxvOFqOaX7/o87 X-Google-Smtp-Source: APXvYqz02tw9mMb0OtKeZ2W98zeRoHwxKY7XE2woJy2A8vtl93nXys5C7sVpsVp2/N99zMzUyfh+KRmcoF+IJQVn X-Received: by 2002:ac8:3811:: with SMTP id q17mr99190639qtb.315.1561386806511; Mon, 24 Jun 2019 07:33:26 -0700 (PDT) Date: Mon, 24 Jun 2019 16:32:52 +0200 In-Reply-To: Message-Id: <41e0a911e4e4d533486a1468114e6878e21f9f84.1561386715.git.andreyknvl@google.com> Mime-Version: 1.0 References: X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog Subject: [PATCH v18 07/15] fs/namespace: untag user pointers in copy_mount_options From: Andrey Konovalov To: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: Catalin Marinas , Vincenzo Frascino , Will Deacon , Mark Rutland , Andrew Morton , Greg Kroah-Hartman , Kees Cook , Yishai Hadas , Felix Kuehling , Alexander Deucher , Christian Koenig , Mauro Carvalho Chehab , Jens Wiklander , Alex Williamson , Leon Romanovsky , Luc Van Oostenryck , Dave Martin , Khalid Aziz , enh , Jason Gunthorpe , Christoph Hellwig , Dmitry Vyukov , Kostya Serebryany , Evgeniy Stepanov , Lee Smith , Ramana Radhakrishnan , Jacob Bramley , Ruben Ayrapetyan , Robin Murphy , Kevin Brodsky , Szabolcs Nagy , Andrey Konovalov Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch is a part of a series that extends kernel ABI to allow to pass tagged user pointers (with the top byte set to something else other than 0x00) as syscall arguments. In copy_mount_options a user address is being subtracted from TASK_SIZE. If the address is lower than TASK_SIZE, the size is calculated to not allow the exact_copy_from_user() call to cross TASK_SIZE boundary. However if the address is tagged, then the size will be calculated incorrectly. Untag the address before subtracting. Reviewed-by: Khalid Aziz Reviewed-by: Vincenzo Frascino Reviewed-by: Kees Cook Reviewed-by: Catalin Marinas Signed-off-by: Andrey Konovalov --- fs/namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/namespace.c b/fs/namespace.c index 7660c2749c96..ec78f7223917 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2994,7 +2994,7 @@ void *copy_mount_options(const void __user * data) * the remainder of the page. */ /* copy_from_user cannot cross TASK_SIZE ! */ - size = TASK_SIZE - (unsigned long)data; + size = TASK_SIZE - (unsigned long)untagged_addr(data); if (size > PAGE_SIZE) size = PAGE_SIZE;