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Mon, 23 Nov 2020 19:49:14 +0000 (GMT) Received: from sig-9-65-241-175.ibm.com (unknown [9.65.241.175]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id E380E52057; Mon, 23 Nov 2020 19:49:10 +0000 (GMT) Message-ID: <7990c489ed6fb3ae36978820400b7cf60c55c126.camel@linux.ibm.com> Subject: Re: [PATCH v6 0/8] IMA: support for measuring kernel integrity critical data From: Mimi Zohar To: Pavel Machek Cc: Tushar Sugandhi , stephen.smalley.work@gmail.com, casey@schaufler-ca.com, agk@redhat.com, snitzer@redhat.com, gmazyland@gmail.com, paul@paul-moore.com, tyhicks@linux.microsoft.com, sashal@kernel.org, jmorris@namei.org, nramas@linux.microsoft.com, linux-integrity@vger.kernel.org, selinux@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com Date: Mon, 23 Nov 2020 14:49:10 -0500 In-Reply-To: <20201123171800.GA6407@duo.ucw.cz> References: <20201119232611.30114-1-tusharsu@linux.microsoft.com> <20201120124657.GA31468@duo.ucw.cz> <20201122210031.GA26756@amd> <20201123171800.GA6407@duo.ucw.cz> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.28.5 (3.28.5-12.el8) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312,18.0.737 definitions=2020-11-23_17:2020-11-23,2020-11-23 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 clxscore=1015 mlxscore=0 impostorscore=0 malwarescore=0 mlxlogscore=999 suspectscore=3 bulkscore=0 spamscore=0 phishscore=0 lowpriorityscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011230124 Precedence: bulk List-ID: On Mon, 2020-11-23 at 18:18 +0100, Pavel Machek wrote: > > > Basically every other data structure in kernel is "critical" by your > > > definition, and you can't really measure them all; some of them change > > > rather often. Going piecemeal does not really help here. > > > > Agreed, measuring data structures that change is not really applicable. > > However, measuring data structures that once initialized don't change, > > does make sense (similar concept to __ro_after_init). The attestation > > server doesn't need to know anything about the measurement, other than > > more than a single measurement is indicative of a problem. > > So, why not simply measure everything that is ro_after_init? I guess we could, but the original discussion, a long time ago prior to LSM stacking, was limited to measuring the LSM hooks. Mimi