Received: by 2002:a05:6359:c8b:b0:c7:702f:21d4 with SMTP id go11csp820847rwb; Wed, 28 Sep 2022 09:28:30 -0700 (PDT) X-Google-Smtp-Source: AMsMyM7xhBaDB5ukDznX8QR6ZNMg+DqmtfhdFb8CwEr1p/vgDE/Hex/I6SQbHbxfrydL+fn6SmN5 X-Received: by 2002:a17:907:868c:b0:782:d6b3:33bc with SMTP id qa12-20020a170907868c00b00782d6b333bcmr21480619ejc.134.1664382510005; Wed, 28 Sep 2022 09:28:30 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1664382509; cv=none; d=google.com; s=arc-20160816; b=zRnRae8E6bxh4PGkYbJggdF225Hz4PCqBEuL5IciB2aaHqfn4eS9LqdxviM/K6lDlf rDS6FWXqylrkFZx+upA5g6P7X753mVmUoB7xGxVe3xkP3g0iSoWS3LUXvsvAcw9tXY/t uUgVcZ7ux9WMobqPmyRG3XqptJXZBFrQxEckqkQaA9+xFC1RtCJkyZZHCVxGoeOOZrQx SZ59CQWsYphPly+wfVzugGs0D/8rj4MbL3lBibs1GIFyFuLZigWyOIQ29puyhstqJst7 Tj+hXLueWFui1bPKbkb5C63T6iLxDMyElXyX5XQxXH2Xtsb9/UGaaA22+n4Y/XQ3v+Lu eCuA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:mime-version:message-id:date:references :in-reply-to:subject:cc:to:from:dkim-signature; bh=YAtibWuc5oMzVqp55WCKs72Sw0/ah0i5PLNnJUPSc5w=; b=ZdxK2v/pNPnouxxLL+D6rpmt7uM44C8XByXushn/bbh4QE5c2kTUBmOhkjGhgEKhHM ncBfgHIzkVtvnbFSKcw9w9bO7jEkq9EM5ZGH9UgQ/IKoun1G13JtxEkr6h89ccm4RmbT VLPd+SI2kcJ4f0ii1hLdHMuGtkGrPLu7lDj9cg8C0zunjonvV678GKFmVIBcS7DAW4OQ iThHWoNMW/F0sVHoopssDpmPJY3tvVxp1KMm6XscYgCjYBAOTXBYhAno5KrBNNzY9gSo 9ayoPiiOE7C/DBpiOOlhKUhdFRU1YY+DOEsom2UgG7qpQpVlv2DfducKkU/5/DYXBJQP Uy1g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@ibm.com header.s=pp1 header.b=k0FdBy8B; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com Return-Path: Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id jr22-20020a170906a99600b007470b52f94esi4239056ejb.199.2022.09.28.09.28.02; Wed, 28 Sep 2022 09:28:29 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@ibm.com header.s=pp1 header.b=k0FdBy8B; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=ibm.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234467AbiI1QX5 (ORCPT + 99 others); Wed, 28 Sep 2022 12:23:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52630 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233410AbiI1QXZ (ORCPT ); Wed, 28 Sep 2022 12:23:25 -0400 Received: from mx0b-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7F20AE234A; Wed, 28 Sep 2022 09:23:24 -0700 (PDT) Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 28SGK5sK001882; Wed, 28 Sep 2022 16:23:11 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : in-reply-to : references : date : message-id : content-type : mime-version; s=pp1; bh=YAtibWuc5oMzVqp55WCKs72Sw0/ah0i5PLNnJUPSc5w=; b=k0FdBy8BRhsithYUgRc3uwuCPWhJJxiLNaPd8IPG96Z9dMHwvFhZPRZbvRFbDmxKorQ1 6yRrX71etg1LdhU+rFuyiJOQ2qg8sZ4NOKF2nEypE3qzI+2XGpuxhAW/3FDkwLkYID8U HZ5nZyQppHngxobcklqLspX1NLTjDvlhTZZurxCgdTq0RxYnfu0DwvAx++2kcA0GcgEy dfcmBx2KpWDzoVPMQ6flYrnCxd7a8Rme5CtEr6cRge7xV/lwkI8+/J1Q49ZK28rDfqBg yvBqF3d4tG0Bki9x7BFPKF1CtG+Ui1wjJ6Tq1TO/MKTm1sSkp1Ir/hWcTskPYtLO+NjH uQ== Received: from ppma03dal.us.ibm.com (b.bd.3ea9.ip4.static.sl-reverse.com [169.62.189.11]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3jvqxp46c5-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 28 Sep 2022 16:23:11 +0000 Received: from pps.filterd (ppma03dal.us.ibm.com [127.0.0.1]) by ppma03dal.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 28SGLRaF011582; Wed, 28 Sep 2022 16:23:10 GMT Received: from b03cxnp07028.gho.boulder.ibm.com (b03cxnp07028.gho.boulder.ibm.com [9.17.130.15]) by ppma03dal.us.ibm.com with ESMTP id 3jssha37fy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 28 Sep 2022 16:23:10 +0000 Received: from smtpav02.dal12v.mail.ibm.com ([9.208.128.128]) by b03cxnp07028.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 28SGN9YO46268826 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 28 Sep 2022 16:23:10 GMT Received: from smtpav02.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DE0195805C; Wed, 28 Sep 2022 16:23:08 +0000 (GMT) Received: from smtpav02.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id CAE895805E; Wed, 28 Sep 2022 16:23:08 +0000 (GMT) Received: from localhost (unknown [9.41.178.242]) by smtpav02.dal12v.mail.ibm.com (Postfix) with ESMTP; Wed, 28 Sep 2022 16:23:08 +0000 (GMT) From: Nathan Lynch To: Andrew Donnellan Cc: jmorris@namei.org, mpe@ellerman.id.au, paul@paul-moore.com, serge@hallyn.com, gcwilson@linux.ibm.com, nayna@linux.ibm.com, linuxppc-dev@lists.ozlabs.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/2] powerpc/rtas: block error injection when locked down In-Reply-To: <591a3e016605181e119496992027ae21700a2c3b.camel@linux.ibm.com> References: <20220926131643.146502-1-nathanl@linux.ibm.com> <20220926131643.146502-3-nathanl@linux.ibm.com> <591a3e016605181e119496992027ae21700a2c3b.camel@linux.ibm.com> Date: Wed, 28 Sep 2022 11:23:08 -0500 Message-ID: <87y1u3pixf.fsf@linux.ibm.com> Content-Type: text/plain X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 0WZREWqYnhMhJI2Fp2k2r6ADwAiGOteU X-Proofpoint-GUID: 0WZREWqYnhMhJI2Fp2k2r6ADwAiGOteU X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-09-28_07,2022-09-28_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 malwarescore=0 mlxlogscore=771 impostorscore=0 mlxscore=0 suspectscore=0 spamscore=0 priorityscore=1501 phishscore=0 bulkscore=0 lowpriorityscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2209130000 definitions=main-2209280096 X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andrew Donnellan writes: > On Mon, 2022-09-26 at 08:16 -0500, Nathan Lynch wrote: >> The error injection facility on pseries VMs allows corruption of >> arbitrary guest memory, potentially enabling a sufficiently >> privileged >> user to disable lockdown or perform other modifications of the >> running >> kernel via the rtas syscall. >> >> Block the PAPR error injection facility from being opened or called >> when locked down. >> >> Signed-off-by: Nathan Lynch > > Is there any circumstance (short of arbitrary code execution etc) where > the rtas_call() check will actually trigger rather than the sys_rtas() > check? (Not that it matters, defence in depth is good.) Fair question! There are no in-kernel users of rtas_call() that pass the error injection tokens as far as I could tell. Nor am I aware of any out-of-tree users, for that matter. But rtas_call() is the likely most appropriate place to have the lockdown gate should that situation change (as it might, see https://github.com/ibm-power-utilities/librtas/issues/29).