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Bruce Fields" , Chuck Lever , Trond Myklebust , Anna Schumaker References: <20201019195257.10728-1-michael.weiss@aisec.fraunhofer.de> <20201019195257.10728-3-michael.weiss@aisec.fraunhofer.de> <87eell46y2.fsf@nanos.tec.linutronix.de> From: =?UTF-8?Q?Michael_Wei=c3=9f?= Message-ID: Date: Tue, 27 Oct 2020 12:56:34 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.3.1 In-Reply-To: <87eell46y2.fsf@nanos.tec.linutronix.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [178.27.102.19] X-ClientProxiedBy: AM0PR01CA0178.eurprd01.prod.exchangelabs.com (2603:10a6:208:aa::47) To VE1P194MB0814.EURP194.PROD.OUTLOOK.COM (2603:10a6:800:16e::20) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [192.168.3.194] (178.27.102.19) by AM0PR01CA0178.eurprd01.prod.exchangelabs.com (2603:10a6:208:aa::47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3499.18 via Frontend Transport; Tue, 27 Oct 2020 11:56:39 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: afa915ae-6972-4e56-05ca-08d87a6f5da0 X-MS-TrafficTypeDiagnostic: VI1P194MB0606: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:9508; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: umVeV0cAMUFeAxTsMdC0fkYZXitWop91g6GrIuqupYM7X/QphFtkrEdSKZJnFyg7c/IPIOcoZEzRy2q1fI/sufXxnuQGdx9VPfCKD0Ijw8D52lHAaYDAlY620j1rmr5sS6Px/Ziei6SZNhPGkkGfeorAWu637N7mda/Eln+8UDLG4og/sZYn8YS7tzir1nEa3CDGNWApSL2gXmI/mjcHCN3aJhNujdt0aQLtd2jZwyurdO+eu9RLLMrnQ7HONX1Uu2JNulVvQwQhET/nh/2OLGNkO+NHjP18RCIvIs7VA+IGOBGR4z0djeMZpqUf4bHOW5yEcW5iuVo9iVKm4ZvVzMHUB/y9jy2UL3wijzU9+o5guwvkPL/vLgtQAwOxIAAO X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:VE1P194MB0814.EURP194.PROD.OUTLOOK.COM;PTR:;CAT:NONE;SFS:(4636009)(366004)(376002)(396003)(136003)(39860400002)(346002)(6666004)(66556008)(66476007)(53546011)(2906002)(83380400001)(186003)(6486002)(8676002)(66946007)(16526019)(110136005)(316002)(956004)(2616005)(31686004)(478600001)(26005)(4326008)(86362001)(5660300002)(16576012)(31696002)(8936002)(54906003)(52116002)(43740500002);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData: 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 X-MS-Exchange-CrossTenant-Network-Message-Id: afa915ae-6972-4e56-05ca-08d87a6f5da0 X-MS-Exchange-CrossTenant-AuthSource: VE1P194MB0814.EURP194.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Oct 2020 11:56:40.5414 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: f930300c-c97d-4019-be03-add650a171c4 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: f8QFwCg012Iy/TACu29vG/PX9tPW12k8AylDn29jvKiKAK6VQIEoM/Bgxv8s8GML7fTFZ0hs3B8Silv4VukMOSdNN/BNdDz8JimIIS40XZvrAkNYx9xGGJ8PFEksAVqS X-MS-Exchange-Transport-CrossTenantHeadersStamped: VI1P194MB0606 X-OriginatorOrg: aisec.fraunhofer.de Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thomas, On 26.10.20 11:28, Thomas Gleixner wrote: > On Mon, Oct 19 2020 at 21:52, Michael Weiß wrote: > >> '/proc/stat' provides the field 'btime' which states the time stamp of >> system boot in seconds. In case of time namespaces, the offset to the >> boot time stamp was not applied earlier. However, in container >> runtimes which utilize time namespaces to virtualize boottime of a >> container, this leaks information about the host system boot time. > > Not sure if that qualifies as a leak. The point is that it confuses the > tasks which are in a different time universe. > >From a container isolation perspective this could be interpreted as an information leak, if you want to hide the host systems boot time form users inside of the container. However, since proc is not totally isolated concerning host system information inside of namespaces, I agree to your point. I will take this into account when preparing v5. When amending the tags I will also updated this passage and remove the leak statement. Thanks, Michael