From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 14DE9E7719D for ; Fri, 10 Jan 2025 12:48:58 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 86F4D8D0005; Fri, 10 Jan 2025 07:48:57 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 81F5B8D0002; Fri, 10 Jan 2025 07:48:57 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 672E68D0005; Fri, 10 Jan 2025 07:48:57 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 3D93B8D0002 for ; Fri, 10 Jan 2025 07:48:57 -0500 (EST) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id C0111AE5DB for ; Fri, 10 Jan 2025 12:48:56 +0000 (UTC) X-FDA: 82991521872.01.107DD4F Received: from mx0b-00069f02.pphosted.com (mx0b-00069f02.pphosted.com [205.220.177.32]) by imf08.hostedemail.com (Postfix) with ESMTP id 91C79160021 for ; Fri, 10 Jan 2025 12:48:53 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=EoFXsfFY; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=XIRreRGP; dmarc=pass (policy=reject) header.from=oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf08.hostedemail.com: domain of lorenzo.stoakes@oracle.com designates 205.220.177.32 as permitted sender) smtp.mailfrom=lorenzo.stoakes@oracle.com ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1736513333; a=rsa-sha256; cv=pass; b=e+MgJXozmTi1NyUsW3u5WKUu/TO3NuL4fHKjz3sLSNLH7+mjTeiCbGj70cES2av2Bf7usl fK6rZpSECiZRjjWC/YMHMrM/wfXAIEQq0FkQ7vs5joIF8A1mbo7l16X54+sanNTht/v+Sv vJVVQvXNfqVG4WfOU3PQ1uWNm+4B9D4= ARC-Authentication-Results: i=2; imf08.hostedemail.com; dkim=pass header.d=oracle.com header.s=corp-2023-11-20 header.b=EoFXsfFY; dkim=pass header.d=oracle.onmicrosoft.com header.s=selector2-oracle-onmicrosoft-com header.b=XIRreRGP; dmarc=pass (policy=reject) header.from=oracle.com; arc=pass ("microsoft.com:s=arcselector10001:i=1"); spf=pass (imf08.hostedemail.com: domain of lorenzo.stoakes@oracle.com designates 205.220.177.32 as permitted sender) smtp.mailfrom=lorenzo.stoakes@oracle.com ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1736513333; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=NpSke//z8RtZANN7sjS102wV0vRNkUFLJt/8KJXf6pk=; b=GStUmQhLagD8fwTePl5kaoTecUONmEZNDvGtrGy/42C8fz4graezUOiXTn8ni5Lj6pwhuP nxAbSNmHcI9fgFWxyjFRM4IdddhYd2dGq4ZhQn3wsPrZ5hZPB37+53Ur86nfT5vrUwKGP0 HhVQXW5Td82NiPIookxCGMt83yhTOek= Received: from pps.filterd (m0246632.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 50A9Bosq014690; Fri, 10 Jan 2025 12:48:51 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=cc :content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to; s=corp-2023-11-20; bh=NpSke//z8RtZANN7sj S102wV0vRNkUFLJt/8KJXf6pk=; b=EoFXsfFYCp1nnAzdaba0mNAkX8BWrOeM/W /R2NUd4SKDuEv3uUZPlHNd7wnPaBNSSo5lU+EJrMSCzmmPLQ2NJ5rmsV/Q7Ltk5e zA8NfthgrzN2N+RdyJ1p/EYI76F1zQRXUPgcI0G4YdbuiVlZAhvbhAKEKaVR1oMd o5mLClDU0rB3COkSRF1pptPsledeAjRgL4kmOyp5BrK0w0qR7wG2GA5r622wDVF/ vAvY8LpbbQ9NVZWkPwAJ1aaHx6zjl+S7XtoE1E2SceonFNy37SLjj0M0wUAh+L6x b6wx+oeJ9mdRY8D3FwDiQCixpLKTmPvwaq9Z1FXrRhpLeS1LsLXw== Received: from iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta03.appoci.oracle.com [130.35.103.27]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 442kcx9ehm-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 10 Jan 2025 12:48:50 +0000 (GMT) Received: from pps.filterd (iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 50AC0OBT008534; Fri, 10 Jan 2025 12:48:50 GMT Received: from nam11-dm6-obe.outbound.protection.outlook.com (mail-dm6nam11lp2169.outbound.protection.outlook.com [104.47.57.169]) by iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 43xuec8qqr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 10 Jan 2025 12:48:50 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=NmHPgksnjCnj+EjOPeyGPr6f3El1WTlpJT4L+SeVFnxslCfExmwl2/wmbXDxxIVS4VJaS/EC9+5orQRSvFI2kH28bWu1bKkepFQRioTjFp6Urlht9m6InHSvGZOBJwjig5tqlf/5pjfiv0zpa4foxp02Ryb4m62RWFdCxCt0VrNltukjp11pcZVOj2bgg8LJvTQTHb0oc05vIOUKwp1zUfxzPhyYKEXJhzh65UQx5/63MhGyz++rK/zPqk21C0jQqsdVmkk440kw6+kMByi4gWzt6jxLZX/f8WrBniqYtYlO6GOPYEbMkIJFrgZCro4RtK8XlVcdCp60lfMa5M3hgw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=NpSke//z8RtZANN7sjS102wV0vRNkUFLJt/8KJXf6pk=; b=HiKw0qEhBoZpeqXBdFV/I7gYq5HEAzcFjUsCbKKFW0bQ36O8eKVz2EUfIcj9Pov+Gbd9dmB0EAZ+mKX/lp5BTcU9fM177HPcfuvh/KPSu91Zh9R+0W8CfHkVCVFuoVkbpniDGKKJRXw22Fsmh/8VnsjQrAf5EnFAoxCtHNL8ug+Cj62VaH3+ZksZyXQIPGKTKiPPUYVTF58ZVJhaViHIhHwspgJ8fsKgbYj86HH0NrwePwLYGg4GlZFADcP1jBwrddErlqNrDu9JCq46v2V690lq2MRcUJa2qpN4EQAMR1z6+ApBU61ut8Q8YxHuQLe0wybtO4sklI7LzP3VKWijfg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=NpSke//z8RtZANN7sjS102wV0vRNkUFLJt/8KJXf6pk=; b=XIRreRGPsUfjCeOKGrA14Z1Ko0Pfn/l+tFXcEWOpesW9FAN2zkUx57G+6GM+FOgdsWk5jkE7VTeen5BH7/LEdKh1ui5Q9Amfu35iFeXhhxbYEOVeTE/PlMCI0RQIDdfXQEkA1bhxkOwnguOhgFX4YAgGRTrMG8b/PHnBAkAnd04= Received: from BYAPR10MB3366.namprd10.prod.outlook.com (2603:10b6:a03:14f::25) by CH0PR10MB5178.namprd10.prod.outlook.com (2603:10b6:610:dd::23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8335.12; Fri, 10 Jan 2025 12:48:48 +0000 Received: from BYAPR10MB3366.namprd10.prod.outlook.com ([fe80::baf2:dff1:d471:1c9]) by BYAPR10MB3366.namprd10.prod.outlook.com ([fe80::baf2:dff1:d471:1c9%4]) with mapi id 15.20.8335.010; Fri, 10 Jan 2025 12:48:48 +0000 Date: Fri, 10 Jan 2025 12:48:44 +0000 From: Lorenzo Stoakes To: "Isaac J. Manjarres" Cc: Andrew Morton , kaleshsingh@google.com, jstultz@google.com, aliceryhl@google.com, surenb@google.com, kernel-team@android.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 2/2] mm/memfd: Use strncpy_from_user() to read memfd name Message-ID: <38fbe522-f757-4de9-acf3-1483b90898f6@lucifer.local> References: <20250109185908.1006310-1-isaacmanjarres@google.com> <20250109185908.1006310-3-isaacmanjarres@google.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250109185908.1006310-3-isaacmanjarres@google.com> X-ClientProxiedBy: AM6P191CA0098.EURP191.PROD.OUTLOOK.COM (2603:10a6:209:8a::39) To BYAPR10MB3366.namprd10.prod.outlook.com (2603:10b6:a03:14f::25) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BYAPR10MB3366:EE_|CH0PR10MB5178:EE_ X-MS-Office365-Filtering-Correlation-Id: d05fd62b-81bb-40f7-11ec-08dd31752083 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|366016|1800799024|7053199007; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?3HILbeYgm092wsicWYE0Ken3VJ9EnvUSVeogiYTJOTQcRK7EzMELUQQJIW9T?= =?us-ascii?Q?tPritWfL+S3NfeSiA+kkacuTdkpl7zICyeXGcchuI1NBLo7dfikrxfWM0UGU?= =?us-ascii?Q?35QDUGeNWl+jRfmpXt1vSx/aHzjgxCCEPpevkundGbC3+4y7SF6eScnGPxs8?= =?us-ascii?Q?FvuOgPXJU9qI5btlQqqUz7o/swKgaqd++7vz86dgdyeVysqMbJFp7lWytUb5?= =?us-ascii?Q?CgKvKTafhLd2n1gXfjokHYR2sHEnA898ts09XM626zZiF3xjc2CjtyI2/oWy?= =?us-ascii?Q?3nn/LpuP8wFMGW37I5UFQssua1uVKwPDTZe2rNXfuprUn03BAyeF5UOcgUN/?= =?us-ascii?Q?XI07JMFfc/XQb35dCmNbV/uyqa8ia68y9m5jW2yBMgc2yxTnK3WaKjyF2V2d?= =?us-ascii?Q?R59lVYtAiONeCAkpD8sHGuz0h1ie2ApJZcfLuyBorM/RLRFR8WqsFxKH0NtE?= =?us-ascii?Q?fgZ+r+zV2V7Qyx9zLfu9BzhDlXe+m9ChYEbCWFiZcFSfPFvqvybe6KqiXYKH?= =?us-ascii?Q?4MPUbWlPIoP+quUsmQ1fStf6cCt1jGviUt6jYELFTDwzq/R78muXwKXvKV55?= =?us-ascii?Q?z0EaAOXYVp/YWsW5ug5lfBewe1N6TdEf+F+5maxouTqepaqhqq4MWncKPchZ?= =?us-ascii?Q?WC5mxAPxKEr8WX87Dvo3eYcLD1EIFBzJhngxySNZK0VlNruTbRvmUlCIzC4Q?= =?us-ascii?Q?3uqDwwta5FwRMf/5BUl5Xowwehvt+WuqaPZ805YEHM4uiJdEtLw/vwADBbUY?= =?us-ascii?Q?k6SSFXY3brqrcQAHZa1g6Hr6MYw6zF1XHkM1o6TPhPA+kzIXbtlJ0FNbWhIK?= =?us-ascii?Q?eeIA858RbMp0q0kwin2qImy94/UApNUw7uhLKbVN5L0e/u7Lg2CwTHUv0qFD?= =?us-ascii?Q?qkVAejBSxx6I0W+TC8WTisNRfVnb0DaCY3OOB4KVHiZZPBeuV5wdTGNslYgq?= =?us-ascii?Q?/Qp5v3CG6Np72Jcvbs/T+HfsqvKb9x3QwZCx3eK0N4oPIQTH0alwrOFbD2KU?= =?us-ascii?Q?7+pem3G0V6Cjgi2Jpf7Rxhz4nZRtRNOstbhJdow6OBuQiaNhMpU3MYKG/w06?= =?us-ascii?Q?q+GUq0UJIM7pAmaF/COYC15yRO483QdpuOSJpkWNz9458emuHOT9IE2e722t?= =?us-ascii?Q?YXggGZK42JzhTJzaejdlhig7JC/rxCjkOaem+LxEqHU7xJTw8ksTYU4GDKow?= =?us-ascii?Q?hmHyoOkU48kIpnEYHFABAy1y5ajB2ZI60d6Vhu/bJrn6YhDufHWXV7WRpKAe?= =?us-ascii?Q?mPKhzYHEA1qFXkEw+3dvZAFhh60FsXBGmo7IWMFjwJXrzNvCDknXjaM63dhF?= =?us-ascii?Q?AaBesjsUOhsz0DgV/iPreqc6SqRMEM+qJ3SQO2vUpuRwPGXjS06DgbR3QLw1?= =?us-ascii?Q?kTTa50WbSF2vBULOx8XSQC/dd+kb?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:BYAPR10MB3366.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(366016)(1800799024)(7053199007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?fSDs05iB6hrV34K7KeSlYunQTTGqVlEX//fJDiZlyKLmM7VI7q3h/s9CHI7v?= =?us-ascii?Q?GjVi3aRbjR13AMlZyG8FIKKDR+Y5bQSG34KZsmt9gnMi4AKgXq+fBqAh3Fpz?= =?us-ascii?Q?A82iKc0hdg4lTK0PWjEq7EGYpKs4fYi+C2gJ2GUQIKunfUsa3fyLzufqHu5Z?= =?us-ascii?Q?UVtNV3YDviB3mzeRgmUZhOECKyJOKFEYVRLWiNipG7MJrw3bEhwK81RqJeey?= =?us-ascii?Q?kzzjAP0XGPiQSxio6PitABseRD1Bd9Lh/SpP7kPzcSA7IH00mLs/XKVGAcjb?= =?us-ascii?Q?kkcKQ2Ow8+UaESzhVcYoYClDGQf/mOV10FgXxXsrJfyOX98WbgI+gHsH3hgw?= =?us-ascii?Q?E8BSl3r6lWwHYvLOJnIDzrYC8ah8UMOeMN4X5QaaYY60KF2hO7kx0sahzycn?= =?us-ascii?Q?aBg6hcDV+kjpMrkRDIND0/RgXxxqHk2rDmfX9BtCsdz7vug0RMgHZ01b1UIu?= =?us-ascii?Q?SwCf6QxLh5/mdqMHVfsT8Q+Lj+0hxV5mboRs1RUYWGESo0e0rAQoaObz5jgc?= =?us-ascii?Q?lhLLGOdgV2psMu1WEJvA34ZgKdLzMhhzLyjxrg+Wk06+iu13A97LA4nfUzK2?= =?us-ascii?Q?qMDFpRTIPpe2I+Hh2X1R0ID461jDWksP+rh6/hSY5fnrSAiuPAY9gcquxLVe?= =?us-ascii?Q?QjIe1B8aR9Cfcs/RomafeuEbnzn6QvVtnr9JQBELIWfNg6ViRy/V9/gIX0Kx?= =?us-ascii?Q?Fzuu+GWPwHQUeG/7jNAKEUelSm8tdBDIeP45tQp1plLtRJXN+gBNRODYTRa6?= =?us-ascii?Q?cBI7Hj318+djsKPtpH8fQrW5zV5+pNYLQFI1CFf5T0cVp8OQUpaDki/Od59A?= =?us-ascii?Q?F4FVwMNoUXdy357FUmJgPL8fatuyIPtBWvzqwLUJVEXivzWBiKsA8t9Q+stH?= =?us-ascii?Q?wazKZ/9U4WJ94Sw4rakBGRdoNuBhTvuvx+MTacBv+TzggBaXqUnjyiassv8C?= =?us-ascii?Q?aqRQIYX1lgnWLTqwQYEd2ZJO1aBgAM6pM2+VXxoZQizUIyeeE8/rDdxUFRLs?= =?us-ascii?Q?v5T6ZeAkF9ZpuKSUJWtellFCRoxWhA1e66NaSEbC8X+FtjJygA6sec785FAi?= =?us-ascii?Q?jSybwBwG2a4ZSLHP/MSBOqCh4yNQ4itzzcOl3/DpQopblTkEAba+Q6IyY+38?= =?us-ascii?Q?0cTh1U04om5FwxqADryxlm4xKAQJ0irdCktK0gSz6CSnxeo7PPjPsQGxIzvh?= =?us-ascii?Q?O+UXqyPyNLAsPhL7T5WfO+hl9wCeg9JNb+k0SlEIUVRUcaYCeS8bat31EuUD?= =?us-ascii?Q?obLniI+yKcq8v32AhsTLHFUuBX1R05Nv05jl9ZJqIg9PkcuU2Dlt6sO++2en?= =?us-ascii?Q?mqbaFiRX4EtVNGVoXeWo6p/B+9s/1iarpqbpiuSzLyPud4DudbeR7c5g3BKp?= =?us-ascii?Q?PH26vSbmnhL1cjI0OK6glthKnEfn4gSopJBe941+Ogjo41VcJe5f4J6WqUpB?= =?us-ascii?Q?/NqtECxlgkVG/dzhsEQuhSNO4UAS0isHykvAF32fhmMHWbwV9QOe+HZ3cPGj?= =?us-ascii?Q?cMpBaTYjixQZBwefCI/mvLfAyTpkLIV4xgPAMohKpEAQNDSxCchnRZrDPBnw?= =?us-ascii?Q?9GxPqguFMTRNpqrPmfhVXNLro6YaWZczug5DRWesZenb6UeSGjcGSW0JZAe0?= =?us-ascii?Q?zQ=3D=3D?= 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: d05fd62b-81bb-40f7-11ec-08dd31752083 X-MS-Exchange-CrossTenant-AuthSource: BYAPR10MB3366.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Jan 2025 12:48:48.5665 (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: cq/ShycuC6CJHMki4O4jIkJ1C5OfSNm0mw+y38zTugAYj5ZfsRF67LdFEMCHy34aM6Tl4VyQ/+RchfDHfwJCnNq5103b+HUb51JTBR7Iro8= X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH0PR10MB5178 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-01-10_05,2025-01-10_01,2024-11-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 malwarescore=0 adultscore=0 mlxlogscore=999 suspectscore=0 mlxscore=0 spamscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2411120000 definitions=main-2501100100 X-Proofpoint-ORIG-GUID: bwX_YPYNfgZgXLSvbVhZX7JxhVbJQwnp X-Proofpoint-GUID: bwX_YPYNfgZgXLSvbVhZX7JxhVbJQwnp X-Rspam-User: X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 91C79160021 X-Stat-Signature: qmdj5ogptz4mw487s7mad5kb1zzumhs5 X-HE-Tag: 1736513333-377515 X-HE-Meta: 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 JNQmRz2O 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000005, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Jan 09, 2025 at 10:59:05AM -0800, Isaac J. Manjarres wrote: > The existing logic uses strnlen_user() to calculate the length of the > memfd name from userspace and then copies the string into a buffer using > copy_from_user(). This is error-prone, as the string length > could have changed between the time when it was calculated and when the > string was copied. The existing logic handles this by ensuring that the > last byte in the buffer is the terminating zero. > > This handling is contrived and can better be handled by using > strncpy_from_user(), which gets the length of the string and copies > it in one shot. Therefore, simplify the logic for copying the memfd > name by using strncpy_from_user(). > > No functional change. > > Reviewed-by: Alice Ryhl > Signed-off-by: Isaac J. Manjarres LGTM, Reviewed-by: Lorenzo Stoakes > --- > mm/memfd.c | 20 ++++++-------------- > 1 file changed, 6 insertions(+), 14 deletions(-) > > diff --git a/mm/memfd.c b/mm/memfd.c > index bf0c2d97b940..5b7c5892ba64 100644 > --- a/mm/memfd.c > +++ b/mm/memfd.c > @@ -396,26 +396,18 @@ static char *alloc_name(const char __user *uname) > char *name; > long len; > > - /* length includes terminating zero */ > - len = strnlen_user(uname, MFD_NAME_MAX_LEN + 1); > - if (len <= 0) > - return ERR_PTR(-EFAULT); > - if (len > MFD_NAME_MAX_LEN + 1) > - return ERR_PTR(-EINVAL); > - > - name = kmalloc(len + MFD_NAME_PREFIX_LEN, GFP_KERNEL); > + name = kmalloc(NAME_MAX + 1, GFP_KERNEL); > if (!name) > return ERR_PTR(-ENOMEM); > > strcpy(name, MFD_NAME_PREFIX); > - if (copy_from_user(&name[MFD_NAME_PREFIX_LEN], uname, len)) { > + /* returned length does not include terminating zero */ > + len = strncpy_from_user(&name[MFD_NAME_PREFIX_LEN], uname, MFD_NAME_MAX_LEN + 1); > + if (len < 0) { > error = -EFAULT; > goto err_name; > - } > - > - /* terminating-zero may have changed after strnlen_user() returned */ > - if (name[len + MFD_NAME_PREFIX_LEN - 1]) { > - error = -EFAULT; > + } else if (len > MFD_NAME_MAX_LEN) { > + error = -EINVAL; > goto err_name; > } > > -- > 2.47.1.613.gc27f4b7a9f-goog >