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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 17 Sep 2019 15:18:33 +0100 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x8HEIWxl9109670 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 17 Sep 2019 14:18:32 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C0D7AA4051; Tue, 17 Sep 2019 14:18:31 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EE0F0A4053; Tue, 17 Sep 2019 14:18:30 +0000 (GMT) Received: from localhost.localdomain (unknown [9.80.228.70]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 17 Sep 2019 14:18:30 +0000 (GMT) Subject: Re: IMA on remote file systems From: Mimi Zohar To: "Theodore Y. Ts'o" , Janne Karhunen Cc: Chuck Lever , linux-integrity@vger.kernel.org Date: Tue, 17 Sep 2019 10:18:30 -0400 In-Reply-To: <20190917124533.GD6762@mit.edu> References: <1BF68F78-FA8E-4633-9AB4-AB6E0B10DCB8@oracle.com> <20190917124533.GD6762@mit.edu> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 (3.20.5-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19091714-0020-0000-0000-0000036E27D1 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19091714-0021-0000-0000-000021C3CCAF Message-Id: <1568729910.4975.200.camel@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-09-17_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1909170138 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Tue, 2019-09-17 at 08:45 -0400, Theodore Y. Ts'o wrote: > On Tue, Sep 17, 2019 at 09:30:31AM +0300, Janne Karhunen wrote: > > Could the fs-verity be plugged in as a measurement mechanism in the > > IMA? So rather than calling a hash function, call verity to measure > > and add new set of IMA hooks to report violations that arise after > > execution? IMA policy logic and functionality would be pretty much > > unchanged. > > That is the plan, and it's not hard to do. The question which I've > raised is when should we do it, given that some people believe that > pulling the entire file into memory and checksumming it at exec or > open time is a feature, not a bug. > > Should we use the fs-verity merkel tree root hash as the measurement > function unconditionally if it is present? Or does IMA want to have > some kind of tuning knob; and if so, should it be on a per-file system > basis, or globally, etc. etc. Those are IMA design questions, and > I'll let the IMA folks decide what they want to do. IMA doesn't hard code policy in the kernel, but is based on a single, centralized policy, which contains measurement, appraisal, and audit rules.  Just as the new IMA appended signature support (kernel module signature format)[1] contains a new "appraise_type=imasig|modsig" option, there would be a similar option for fs-verity. Mimi [1] Included in the v5.4 pull request.