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=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 8FE70C11D0C for ; Thu, 20 Feb 2020 16:32:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 64066208E4 for ; Thu, 20 Feb 2020 16:32:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="jMTYwlRb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729013AbgBTQcC (ORCPT ); Thu, 20 Feb 2020 11:32:02 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:55083 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728986AbgBTQbw (ORCPT ); Thu, 20 Feb 2020 11:31:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582216312; 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=IU1fgxlkB6a/1caEc9OlPp7STKLZ6FpW39zfFVLVvVg=; b=jMTYwlRbEv44wFBo6ZMZ4mvdZRFmjMUyEgtYnPMPl8hXTpe45rHWfOpMHxsjm1BsvPsWeX TA/eI3Z0jmTqCwzR658W9SJHi+5RIPahzJbH9JpZqoFQ2UZNPHx5gPFE3DbRxWzO9+4GFF WYFy9/H2W5ULsdrg2a2KqOne4NkhEBs= Received: from mail-qv1-f72.google.com (mail-qv1-f72.google.com [209.85.219.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-407-lzIGG0NbMC6gymwn-YvE6w-1; Thu, 20 Feb 2020 11:31:50 -0500 X-MC-Unique: lzIGG0NbMC6gymwn-YvE6w-1 Received: by mail-qv1-f72.google.com with SMTP id p3so2938273qvt.9 for ; Thu, 20 Feb 2020 08:31:50 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=IU1fgxlkB6a/1caEc9OlPp7STKLZ6FpW39zfFVLVvVg=; b=qjBL/bGUd2iJf6kQJOxfnnPxdJGVTZsq8zFMD5glQUx1V6ENDvemgxhbKyYTJimhBT rYAl81UEQ0OdvFXy7Ol+s8/jha3qVktvj/M2/4ZXBimjnfWqt2KCouBg+/Qb/Jfl+JCx MCAyDyKkyGU7QPUVyyRnCi4Ds7uXnK6siRIO30VoCjYEdQcUn0AFXcMRjuQjPMsgEr9y QEL7HNmZPBmR11OGmAiBTGZ4KO2VnP01KdrUgSOpdYrQcY53l+e4dqwTioFW6xpLNy/s 3x6RyL3kkdxZmsbvYlKM1mYjOq9NdRrTaLs//0ONn4hFnRRMgF1XkR1m6g2WasEnfgM7 xEFQ== X-Gm-Message-State: APjAAAVrysH5ZcDtJvziemNyG6fxVvpuV4+rEiwlF3vLW/2vPSHWeQPU 41oTqX1jb0jcSp44n5Ql3tOfflNTb6yD4CXSJKb63ZhhvgCa5riXxo9/wh7KHfwFGKx4wnJyUQD 6TCPUDmwr2L43tOhDDDegyP8j X-Received: by 2002:a05:6214:450:: with SMTP id cc16mr26380449qvb.175.1582216306769; Thu, 20 Feb 2020 08:31:46 -0800 (PST) X-Google-Smtp-Source: APXvYqzMg51Khw0k2HZsVu+5Fdow6BayCSYLtWlERq1D239QTNW+33WWT4KycPEAwP+32tQ5qNarog== X-Received: by 2002:a05:6214:450:: with SMTP id cc16mr26380415qvb.175.1582216306483; Thu, 20 Feb 2020 08:31:46 -0800 (PST) Received: from xz-x1.redhat.com ([104.156.64.75]) by smtp.gmail.com with ESMTPSA id l19sm42366qkl.3.2020.02.20.08.31.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Feb 2020 08:31:45 -0800 (PST) From: Peter Xu To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: Brian Geffon , Pavel Emelyanov , Mike Kravetz , David Hildenbrand , peterx@redhat.com, Martin Cracauer , Andrea Arcangeli , Mel Gorman , Bobby Powers , Mike Rapoport , "Kirill A . Shutemov" , Maya Gokhale , Johannes Weiner , Marty McFadden , Denis Plotnikov , Hugh Dickins , "Dr . David Alan Gilbert" , Jerome Glisse Subject: [PATCH v6 17/19] userfaultfd: wp: declare _UFFDIO_WRITEPROTECT conditionally Date: Thu, 20 Feb 2020 11:31:10 -0500 Message-Id: <20200220163112.11409-18-peterx@redhat.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200220163112.11409-1-peterx@redhat.com> References: <20200220163112.11409-1-peterx@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Only declare _UFFDIO_WRITEPROTECT if the user specified UFFDIO_REGISTER_MODE_WP and if all the checks passed. Then when the user registers regions with shmem/hugetlbfs we won't expose the new ioctl to them. Even with complete anonymous memory range, we'll only expose the new WP ioctl bit if the register mode has MODE_WP. Reviewed-by: Mike Rapoport Signed-off-by: Peter Xu --- fs/userfaultfd.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 6e878d23547c..e39fdec8a0b0 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1495,14 +1495,24 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, up_write(&mm->mmap_sem); mmput(mm); if (!ret) { + __u64 ioctls_out; + + ioctls_out = basic_ioctls ? UFFD_API_RANGE_IOCTLS_BASIC : + UFFD_API_RANGE_IOCTLS; + + /* + * Declare the WP ioctl only if the WP mode is + * specified and all checks passed with the range + */ + if (!(uffdio_register.mode & UFFDIO_REGISTER_MODE_WP)) + ioctls_out &= ~((__u64)1 << _UFFDIO_WRITEPROTECT); + /* * Now that we scanned all vmas we can already tell * userland which ioctls methods are guaranteed to * succeed on this range. */ - if (put_user(basic_ioctls ? UFFD_API_RANGE_IOCTLS_BASIC : - UFFD_API_RANGE_IOCTLS, - &user_uffdio_register->ioctls)) + if (put_user(ioctls_out, &user_uffdio_register->ioctls)) ret = -EFAULT; } out: -- 2.24.1