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Thu, 8 Jul 2021 14:22:35 +0000 Date: Thu, 8 Jul 2021 10:22:31 -0400 From: Konrad Rzeszutek Wilk To: Juergen Gross Cc: xen-devel@lists.xenproject.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Boris Ostrovsky , Stefano Stabellini , Roger Pau =?iso-8859-1?Q?Monn=E9?= , Jens Axboe Subject: Re: [PATCH v2 0/3] xen: harden blkfront against malicious backends Message-ID: References: <20210708124345.10173-1-jgross@suse.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210708124345.10173-1-jgross@suse.com> X-ClientProxiedBy: MN2PR10CA0032.namprd10.prod.outlook.com (2603:10b6:208:120::45) To BYAPR10MB2999.namprd10.prod.outlook.com (2603:10b6:a03:85::27) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from char.us.oracle.com (130.44.160.152) by MN2PR10CA0032.namprd10.prod.outlook.com (2603:10b6:208:120::45) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4308.19 via Frontend Transport; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?y3ARb6nCAKV3Czv7MtYPpmokDhR/zrnUzhjSPOK7Rcq027a1q0auvcQfbfRh?= =?us-ascii?Q?GrDKA0zJTL9PIf7YUB+svcFOoUY0z/OMzJ5vf73B54cgM4bdTB24ubBak0+d?= =?us-ascii?Q?8CcY/ha3JbHxOzDQlDHtMfdRoKq2/M167r7MpgZPWP39CaFnaR/tm1MBVDfR?= =?us-ascii?Q?nOBVmeDeYPA6dOn8SmfcOc86unJHDXZt/13wzafPAL5o6FioyRBB81T49BsX?= =?us-ascii?Q?NbUaL0M97O1nmigeGpx+PhBuPPawSUYF0BKq+bCmS6pEZX5KzLZ2Lv62ZSxZ?= =?us-ascii?Q?5HxGQWqwXDVK9tygyd+zm0QSA0XLv8dfeuHbLgt8lMUjkjas9MNnwaflR5Gb?= =?us-ascii?Q?PuboWg/NHCL646vFWy4qpdDCTUmi7ZonVW19jIn8HYWxRgv7esjeePAPPMPY?= =?us-ascii?Q?ZkTFe6RMjz67kX03nQKlle5Eu24zIAO+qg0K0cGo1ebELE78Psjym7ccxtue?= =?us-ascii?Q?xPJXYgKB0spNZChvX76VetlRiogU5aqvO5fLs/7LLKiYO9OoHDLJSv/5humf?= =?us-ascii?Q?tcVYDrs6U62UxAa6EaQROPJbweFBUnDgeh5aQNKFiK5licpny3I2iylvDFsj?= =?us-ascii?Q?YGmeR0NaD2v3152+HRZ2jHp5J8fVWNTZ2B2ngxJJUxj1ArYvXXNBy+BOS98R?= =?us-ascii?Q?N5v35WC2su+E46NwySSmhNIH3kErwjIwEbPObmXnAUdeMTJA5KXchFPn1rp9?= =?us-ascii?Q?LiPb4OmXlNTm4RkttT43mDbJytFDhJVLaxSQtOYsxVXO2PKs2htM/mkxf4qP?= =?us-ascii?Q?5wJvNyrY/4KyERZ/3IPI8XiEeWySqoFXb4uc2lTI13xlhzvubYQmS95tGppq?= =?us-ascii?Q?Ym2e9g+fpuCzY5iptD3K1YrwbOLEJlvdDusgnCqh50IEThCcGRwaTQYzD6cq?= =?us-ascii?Q?mdmW3CXXcSCqTp9ldmeKMjG+bW/WjaP/xp9PjXedqX/Hs0sgQUAb0ehogCbo?= =?us-ascii?Q?tCwJAb3dqSWiC41Nz+FK9flmFQJYeWCLS4la9FDY/9X3XKQhpH3sOOKlfaVu?= =?us-ascii?Q?U4SfGYWPfUHzIULcelfC0OMyiHLK0jSu8Vc+srBdhyMNxpIo5mcIrd7Il6j/?= =?us-ascii?Q?Yx6/sz/FKCpOPaCN81TPqk+eZmh+HFAhvCzBQ+XaNcwOFcAhPo5+h/X4au4+?= =?us-ascii?Q?FTDdUCvwVn4knty8ZhJMJmSGDWdfLpUxWcJIX7TF9ypwmNtkEPnuKFB/heVd?= =?us-ascii?Q?Tw6xkEuFJy0cVUbSFKneVg5efVxxllAsZuG9yjH4rkDulgogwldYa5IH+v3k?= =?us-ascii?Q?KOyrwSO3XR81IQ0kesCX+QMZw6xqLmW3ruN9nfinFlK0g9f/7WgcKQCldVPM?= =?us-ascii?Q?49gueOoFptQI5UHmwPf3SHiH?= X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: d36ba2f3-bf74-4b9b-d202-08d9421bd50b X-MS-Exchange-CrossTenant-AuthSource: BYAPR10MB2999.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Jul 2021 14:22:35.6637 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: tJft0CievwA0O/A/blsVuPrNFEgcrqjXzukmfT7Q9lg5oa/01dqMykVWDAbazvIS2uYBPocCX29YIdHHDW8kww== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR10MB4784 X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=10038 signatures=668682 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 spamscore=0 suspectscore=0 phishscore=0 mlxscore=0 bulkscore=0 adultscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2107080078 X-Proofpoint-ORIG-GUID: I-PLq_lY1OLt-zFhG7kTrumscKKdY6nu X-Proofpoint-GUID: I-PLq_lY1OLt-zFhG7kTrumscKKdY6nu Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Thu, Jul 08, 2021 at 02:43:42PM +0200, Juergen Gross wrote: > Xen backends of para-virtualized devices can live in dom0 kernel, dom0 > user land, or in a driver domain. This means that a backend might > reside in a less trusted environment than the Xen core components, so > a backend should not be able to do harm to a Xen guest (it can still > mess up I/O data, but it shouldn't be able to e.g. crash a guest by > other means or cause a privilege escalation in the guest). > > Unfortunately blkfront in the Linux kernel is fully trusting its > backend. This series is fixing blkfront in this regard. > > It was discussed to handle this as a security problem, but the topic > was discussed in public before, so it isn't a real secret. Wow. This looks like what Marek did .. in 2018! https://lists.xenproject.org/archives/html/xen-devel/2018-04/msg02336.html Would it be worth crediting Marek? > > Changes in V2: > - put blkfront patches into own series > - some minor comments addressed > > Juergen Gross (3): > xen/blkfront: read response from backend only once > xen/blkfront: don't take local copy of a request from the ring page > xen/blkfront: don't trust the backend response data blindly > > drivers/block/xen-blkfront.c | 122 +++++++++++++++++++++++------------ > 1 file changed, 80 insertions(+), 42 deletions(-) > > -- > 2.26.2 >