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[141.146.126.79]) by mx.google.com with ESMTPS id o5si7065200jam.81.2019.03.13.13.02.06 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 13 Mar 2019 13:02:06 -0700 (PDT) Received-SPF: pass (google.com: domain of mike.kravetz@oracle.com designates 141.146.126.79 as permitted sender) client-ip=141.146.126.79; Authentication-Results: mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2018-07-02 header.b=bGh1kutl; spf=pass (google.com: domain of mike.kravetz@oracle.com designates 141.146.126.79 as permitted sender) smtp.mailfrom=mike.kravetz@oracle.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x2DJwxnX112519; Wed, 13 Mar 2019 20:01:50 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=AtBAoBWfQ92g/h0jn7C7rV5DlEJTC6rv3QAp7/w/8Co=; b=bGh1kutlaBX9tZaDGFzyE1XGgTUVs18/4uz765iaJsw+6I910sVzJnDuF7bdEHtFNYWc QqUwndVcj2dZ+IGCvky7EFIzyK9BSYl8WWFLnA02EaSpfvShx8+1+40q+SQ2lPApvt/e wKD0Xiud1DXNeckZ211i0Gc96yhVmLPGlbRNLZV335Lzkhfspr5O97LABI8SSP5Q9pld X2tK4OLUl6fFdGDDTKErjWWe75q9cGWD3/pYcOJVivSi+a/Ey0+puKrhqNNTJvcmjv/8 FmLmzcWDndEkqCaUK5IkQcuhxhtqBKGcO+5DQDxsfj8y4BlfFf8iDAhwUmYuJPqbAYgh sw== Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by aserp2130.oracle.com with ESMTP id 2r430ewrvh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 13 Mar 2019 20:01:49 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id x2DK1mc4007502 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 13 Mar 2019 20:01:48 GMT Received: from abhmp0005.oracle.com (abhmp0005.oracle.com [141.146.116.11]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x2DK1gxM016936; Wed, 13 Mar 2019 20:01:42 GMT Received: from [192.168.1.222] (/50.38.38.67) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 13 Mar 2019 13:01:42 -0700 Subject: Re: [PATCH 0/3] userfaultfd: allow to forbid unprivileged users To: Andrea Arcangeli , Paolo Bonzini Cc: Peter Xu , linux-kernel@vger.kernel.org, Hugh Dickins , Luis Chamberlain , Maxime Coquelin , kvm@vger.kernel.org, Jerome Glisse , Pavel Emelyanov , Johannes Weiner , Martin Cracauer , Denis Plotnikov , linux-mm@kvack.org, Marty McFadden , Maya Gokhale , Mike Rapoport , Kees Cook , Mel Gorman , "Kirill A . Shutemov" , linux-fsdevel@vger.kernel.org, "Dr . David Alan Gilbert" , Andrew Morton References: <20190311093701.15734-1-peterx@redhat.com> <58e63635-fc1b-cb53-a4d1-237e6b8b7236@oracle.com> <20190313060023.GD2433@xz-x1> <3714d120-64e3-702e-6eef-4ef253bdb66d@redhat.com> <20190313185230.GH25147@redhat.com> From: Mike Kravetz Message-ID: Date: Wed, 13 Mar 2019 13:01:40 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190313185230.GH25147@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9194 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 lowpriorityscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1903130137 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: On 3/13/19 11:52 AM, Andrea Arcangeli wrote: > > hugetlbfs is more complicated to detect, because even if you inherit > it from fork(), the services that mounts the fs may be in a different > container than the one that Oracle that uses userfaultfd later on down > the road from a different context. And I don't think it would be ok to > allow running userfaultfd just because you can open a file in an > hugetlbfs file system. With /dev/kvm it's a bit different, that's > chmod o-r by default.. no luser should be able to open it. > > Unless somebody suggests a consistent way to make hugetlbfs "just > work" (like we could achieve clean with CRIU and KVM), I think Oracle > will need a one liner change in the Oracle setup to echo into that > file in addition of running the hugetlbfs mount. I think you are suggesting the DB setup process enable uffd for all users. Correct? This may be too simple, and I don't really like group access, but how about just defining a uffd group? If you are in the group you can make uffd system calls. -- Mike Kravetz