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;
Message-ID: <6300a33a-9d3d-42a2-d332-81e02d52d310@oracle.com>
Date:   Wed, 26 Apr 2023 09:32:54 -0700
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0)
 Gecko/20100101 Thunderbird/102.10.0
Subject: Re: [PATCH V4 2/2] blktrace: allow access trace file in lockdown mode
Content-Language: en-US
To:     Jens Axboe <axboe@kernel.dk>, linux-kernel@vger.kernel.org,
        linux-security-module@vger.kernel.org, linux-block@vger.kernel.org
Cc:     paul@paul-moore.com, nathanl@linux.ibm.com, jmorris@namei.org,
        serge@hallyn.com, konrad.wilk@oracle.com, joe.jin@oracle.com
References: <20230420215331.88326-1-junxiao.bi@oracle.com>
 <20230420215331.88326-2-junxiao.bi@oracle.com>
 <05b3eebd-7a3f-13d5-1fe9-8f4ab3080521@oracle.com>
 <30ab7555-8f36-cfb7-9101-0ebb92af3c2f@kernel.dk>
From:   Junxiao Bi <junxiao.bi@oracle.com>
In-Reply-To: <30ab7555-8f36-cfb7-9101-0ebb92af3c2f@kernel.dk>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?MU9paUp0SjlDeVVSajFwVGlhQUFnTEkwUkF5UlRrQ0NyQ2tDUEJualArYktN?=
 =?utf-8?B?VURPR3k3R1JzalVRYnc3V3cyRUVPUEdBOTV4RGFvaWxZenhrN0ZscnJPSFpm?=
 =?utf-8?B?NDI1SlFaWEhHenZiZURYZVM5V3FyRjZHWGZZUS9ZTktpOXVLNnF3cHd4WE5J?=
 =?utf-8?B?S1poMlZOZ1M5UTkzcHc2R0lKVEF6Snh2R3RmekEzUHZtZWxobXJXWElGZlFr?=
 =?utf-8?B?YkVRZTl1RFFWdk83QnE1TWdrUkxMUlNzYW1WNitnRlAxazlIT2dPYzBvOWh4?=
 =?utf-8?B?VXg0aUZ4ZUdtUEQxVittby9walNFcnhkODVzNU56STYxTS9qcnUxdktZL0Js?=
 =?utf-8?B?clhWNDlEd0RGbE5kblozbmFqRC95VWxlMEtTWmxHSUMza3VkME9IbElITlFN?=
 =?utf-8?B?SDJvbm1FdUtLcmVtN2pISTJtZ01XSmlzSWdvSFVKbytGOExtZ05Oa3FEV0RX?=
 =?utf-8?B?WTgxMVN6NVBBdTdFNjR6Rk1uRk1FZDB4QW4vc29oVERrYzY5YkpoeGFRbkhu?=
 =?utf-8?B?QktRdjRKNndybmdsV0N2NU5adnJXbnllamQzcmtSSU5EZGpJMTU1SHhyQTE0?=
 =?utf-8?B?YXRkUytNUDNySmtYWW9aUzhFcGVPZ3dTL2ZsSjcvWnJUNGdOWTlDZm4wUkhE?=
 =?utf-8?B?WXd5eGpWMEx3M1NjNTkzdE1ld3JEKzE3QmdBeWptQWxoa09sUGZqM28wNVhl?=
 =?utf-8?B?dkNtQjVtOGRBL0V2eWxMWitwTWovTkxkaDRDeE94NmNQRXpLQWNnUGtqdmFl?=
 =?utf-8?B?aGZuNlpja1h0UWRZeERkdEVpbUdXNSswd2U0cytJZUVwR0JLSTNUdnNsbXgy?=
 =?utf-8?B?T2tPOTlJVmtOZXRkdkpha1ZJNElIVTZnZE5DeFFtZUhzMVVHV3AvempWclZx?=
 =?utf-8?B?Z2VRYU9NK0g5RExWTzl0WktnaXg2VGQyUmVUZm81dWJYTFgvc2E2MG05bDFI?=
 =?utf-8?B?RmFyVlNmUjE1RWxKYmpCMVZVenRCZUU3OUdTT0JIR1NiUHdya21BM053LzVm?=
 =?utf-8?B?M040Q0pNaGM4V01BTkx3UUN4QnVZRnBSM2tCYTJtK0lPWHl0a3pWT2xMVjRQ?=
 =?utf-8?B?WFcyQTV4T2k2NXJ2ZWljWDgxUHIrRTA5N2w2NmdRcDFGVXl2L2lkZXVTeFJp?=
 =?utf-8?B?WXlFOFNkVUt5NUNjd0VvWVg5V1RHSkJ6Q2Fsak0rRHlSbCtwSUs5THVSdUw0?=
 =?utf-8?B?S00wRkc5a1U2VUJFM09KWFJESU53SVdJVVB0ME0rVTNBR3RrTzVBcU9ubVN0?=
 =?utf-8?B?cC9oWVhNMkRxWG9Qd3d0RWdiM2tUTXdtR2JNUmMvQWdsY2ZqcDFybVN0N2Jh?=
 =?utf-8?B?WllaV3g3THhVbEhieW5ZcytyN3FHazB3TUtHVC9zenU3VTlxZU9GRWNiWTJJ?=
 =?utf-8?B?UzhKd002T0JkOENuejZJc2pPWTBEUFZMb0EySzg4SE1EOXZFbGpCLzJEeXpJ?=
 =?utf-8?B?Vjg4K2IwdW1WMHIrNFNyZkNENXNwMk5WSW9UYlZaY2w4NUR2cStycnhkMlA4?=
 =?utf-8?B?dHU5cUllemgvQTRSWENzZ2NVQkdteFQ1Zm8wWlpsT3F4QmpWcVZnOS9ZSnpj?=
 =?utf-8?B?QW84UVowM3E0T1lEN3Z2Nk1qVXFDV0R0RDN5c1dNazllMFI0TG5TRXMxbDVO?=
 =?utf-8?B?cWV4MldDdWRPWEFKUm1UQ01nQkdiZFk1bUQ1NDhYbk4yU1BHNUtWTHRVWXZH?=
 =?utf-8?B?b29HbFhPdUVjdlAzOWNyWjJmV1hFejNlMDNVcWdmVWRTY2VudDJmZ0pnZGt5?=
 =?utf-8?B?WE9UemZHTVRvRlFwekxmUVJDWEJ4WDlyVkJrRG9OMnFFMC9LekNhcEExbnJo?=
 =?utf-8?B?eUhKQjYxTlZjY3Z5UGVCb1R6WTh1bGhTRXQ4K0lDOXZMN2JzeEgxQkwwZlJx?=
 =?utf-8?B?K2FrR0FXUHhJOVFNdjB1dnNOY3EzQkYxWTF1amdwaHlzNU9vTVBYaVh1dG94?=
 =?utf-8?B?dXN1UWpiM3VsNWRPOTFJWnRXc1M4c1dLNWZ3bW10am8rQ1dFOVFNNXhidkln?=
 =?utf-8?B?eWRDc3ZsWVRlbzV6SHI1UW05dE5uRkRkY0xiencwU1AyT1RTWEVudzRoOS8v?=
 =?utf-8?B?RUhhMWlURHlvclVpc0pDd0pzYjZCNFhSZ0M4dFAyR3VRNUR6Yjg3cFlaM21J?=
 =?utf-8?Q?XNW88ayxmJ8fswv0XwhCqJT4K?=
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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
X-OriginatorOrg: oracle.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 7ee2a7f3-4aaf-4e9e-9ee3-08db4673e3f7
X-MS-Exchange-CrossTenant-AuthSource: SJ0PR10MB4752.namprd10.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 26 Apr 2023 16:32:56.4803
 (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: u2FgmgJQft4tqiPhcyZmCIvB75V7am7foZAjPNguGbdN7bMXXBwlMO2Gzhlkg2e3EUX3ry2js4dQ/hfETo7k4g==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ1PR10MB6003
X-Proofpoint-Virus-Version: vendor=baseguard
 engine=ICAP:2.0.254,Aquarius:18.0.942,Hydra:6.0.573,FMLib:17.11.170.22
 definitions=2023-04-26_08,2023-04-26_03,2023-02-09_01
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=678 spamscore=0
 malwarescore=0 mlxscore=0 adultscore=0 suspectscore=0 phishscore=0
 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1
 engine=8.12.0-2303200000 definitions=main-2304260145
X-Proofpoint-ORIG-GUID: aySIAbyJT9IntZ06Jz51zvhqEp9M0Pqs
X-Proofpoint-GUID: aySIAbyJT9IntZ06Jz51zvhqEp9M0Pqs
X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,RCVD_IN_DNSWL_LOW,
        RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE
        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: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 4/25/23 12:12 PM, Jens Axboe wrote:

> On 4/25/23 11:55?AM, Junxiao Bi wrote:
>> Any IO folks can help review this patch?
>>
>> Paul needs a confirm from you that the information blktrace exporting
>> to userspace through the relay files are safe, not leaking information
>> that userspace shouldn't know in lockdown mode.
> I don't know anything about what lockdown is, but in terms of blktrace,
> it is a way to trace meta data associated with IO. It'll tell you things
> like "task T wants to {read,write} on device D, at offset X, and of size
> Y". For passthrough IO, it'll also dump the CDB. There's never any
> actual data traced.

Thanks Jens. Lockdown is a security feature which is trying to limit 
user's(including root) capability to access security sensitive 
information inside kernel, there are two modes, read-only access is 
allowed in "integrity" mode while both read and write access are 
disabled in "confidentiality" mode.


Paul,  do you have any other concerns regarding blktrace? As Jens 
mentioned, blktrace just exported IO metadata to Userspace, those were 
not security sensitive information.

Thanks,

Junxiao.