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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 208C5C46467 for ; Tue, 10 Jan 2023 17:16:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234079AbjAJRQl (ORCPT ); Tue, 10 Jan 2023 12:16:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47836 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231996AbjAJRQi (ORCPT ); Tue, 10 Jan 2023 12:16:38 -0500 Received: from NAM12-BN8-obe.outbound.protection.outlook.com (mail-bn8nam12on2086.outbound.protection.outlook.com [40.107.237.86]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 712FB271A9; Tue, 10 Jan 2023 09:16:36 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=XFp3mmYzMf+V67z3yMgrKh2WTVjmgAziBhCp92cXPdMGVz02IMvqQrixH1BHFUI4lcH6FqfMpXLRHLRMeOVtrjHtS6A8w9NTVvLZvDUoxcnWWlq8wN1F4VXhpdGFlxXYDquvij+L+t/1hz08E96pZQYxuvbq/SYoK1yEXci1wL74LnJWX0ZyGNcYarUQeSLSjXXQ/VEpWUHt9V3RpONmg8Y+35vbylR4Bh31T68+s/n6vAHplKMyvpR/4A98/gpRJz+MBiVZgxYV4u2WsU7yfg0sCEYp1ygCAgA5KOVCKqTegrpt2gynBLYPqKCLer1hZbWjKHclQvkViAxyBzSUxg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; 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=CySotVvQVx7uZp996yp3s3RdxWgYqVVVDIFNPXi9rHs=; b=AAiR0kOZEgVPDV4CPNsNLZqV5NU06KEtUaI7lhC+Lt56pn/fPDHpoHOuyNa1oLZ0MwzKaGyovfeAUqUC4ni4ZqGCOCG3f5mAm7AuTT14vz6MdXfy1QnnsQbB9AhCYZU9Vd08Yx+UZ7fY7jUZiGFjrAIC8AyzKBLG0M69ECh4mHrkomUInO2OsFFeH9aaHYcbTN9Am8JTCamKIXnJCX6iK2vThVYDL1Wv3ixkFDNFrX78UKH9ait7TPae3avJYUdx9NG82zNONHn+NNrvykqS1avARB8c5y8dtwV0mlWyZMpAtwpYX3xzB4/MmRhhugQ7AYPMMvFiVGZ9as+qTZP50Q== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=amd.com; dmarc=pass action=none header.from=amd.com; dkim=pass header.d=amd.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=CySotVvQVx7uZp996yp3s3RdxWgYqVVVDIFNPXi9rHs=; b=wQd8XavsSbdPReZJ7wGRPUaKZ6GvlbQdIugQxqh0W/3+FzTmsMb+8FuX9mOxjfryutqr0bjTDmwfE/qFCAsNPk0csJeSxIh9gCxIKBVCA465zwqOGq1toIuCkOzUJaeRSbXoebDXd2aZnvIUMgFzoHnIU5Vki0/FrmShWdwsBYE= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from DM4PR12MB5229.namprd12.prod.outlook.com (2603:10b6:5:398::12) by SJ0PR12MB6853.namprd12.prod.outlook.com (2603:10b6:a03:47b::17) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5986.18; Tue, 10 Jan 2023 17:16:33 +0000 Received: from DM4PR12MB5229.namprd12.prod.outlook.com ([fe80::8200:4042:8db4:63d7]) by DM4PR12MB5229.namprd12.prod.outlook.com ([fe80::8200:4042:8db4:63d7%4]) with mapi id 15.20.5986.018; Tue, 10 Jan 2023 17:16:33 +0000 Message-ID: Date: Tue, 10 Jan 2023 11:16:30 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Subject: Re: [PATCH] KVM: sev: Fix int overflow in send|recieve_update_data ioctls Content-Language: en-US To: Peter Gonda Cc: kvm@vger.kernel.org, Andy Nguyen , David Rientjes , Paolo Bonzini , Sean Christopherson , stable@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230109160808.3618132-1-pgonda@google.com> <74745684-785e-71b2-288e-91fbcf1b555b@amd.com> From: Tom Lendacky In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: MN2PR06CA0016.namprd06.prod.outlook.com (2603:10b6:208:23d::21) To DM4PR12MB5229.namprd12.prod.outlook.com (2603:10b6:5:398::12) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM4PR12MB5229:EE_|SJ0PR12MB6853:EE_ X-MS-Office365-Filtering-Correlation-Id: a56a3be6-af81-4976-5b38-08daf32e6c02 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: bjKm84j57SDRRFyRhRn11rbc1CNLI6HrBrcvQQa2SArP97t6WrgrVrC6ss1OovsSfN+Z2W/add/ROTznE3utNqoKWdiUCbYWOJb6/K93ALwXryD1qGteFdhXivUxLZGOpgxLKHwuyYG5L/BN/jNkU7sc6sLsLtuloh3w91OlbfxiN3mj+vLtsNRLnsv58AV5A8kVjPLcssGpFIfG6ywy3pn2ZiU8QNoaoeTjmA5AE5yPACoR+S+oQNkePnNXoQDyIMDNIg0ZY5Jd3/qRloti1OzbmKlHzv2CtoFVgvyhCC7vaSu9Xbi1sdd+eNAs08H5jWHcea56f/orCT1SJQ+RqwdtDlzzWcpv3YcfNYsmOdo89wdETQHMERl7TYWiyugK/+w3KPousJi8SUVaGn3dFsJEOMBmyrUKXtanLHAImcKtuEfl3nkM2n4B7VaSh+C11SJ+4y18BbCRdp9Eit6EG2iaztOTkyG/MgjXRulwz955OiBcXMV8fPctK3iMf2EEaa7wm849oGATlsKUCvWVx/iw727Z+YzjdzwGnsoJxWprs1Ah2mGI5FqRijfra1AB00PJ9UNqhESf9iRH6mbqSmoYcbr1V/RR9OCEFCpyMaIclydTK7VmSiRbvUYB4+3vW1J24UmlYjp0RRVUsRfenpm4aKVkHGKlWcK3aM7ORPTsLiIGdX8V6TfNEQDf6wYtz+nVLA6OVDjqNcb3KJHUN4I+HzeHnUIxZUXDOn1koZM= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DM4PR12MB5229.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230022)(4636009)(346002)(366004)(396003)(39860400002)(136003)(376002)(451199015)(66946007)(41300700001)(316002)(54906003)(2616005)(4326008)(66476007)(36756003)(66556008)(8676002)(6916009)(86362001)(31696002)(38100700002)(8936002)(5660300002)(83380400001)(2906002)(6506007)(53546011)(31686004)(26005)(6486002)(6512007)(478600001)(186003)(45980500001)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?UENTMk5DOWNoakpSNHk3SFlia2pVZHJCUnpGWk5ic01YMmJ5NUR1V3BiMWZL?= =?utf-8?B?bDRKSlVhQ1llNmhsQ1hqSEh6cUVYOUxKbjJ3WTI1U3pJeHczbEhIRlNadEw3?= =?utf-8?B?MW5QVnhsM3dSelZ5MHZnaXg2VnJHSE53NDcrcklMck9tVFVZTmc5ZE9jSzVy?= =?utf-8?B?cGF2R3FBWHlxWGhCTWdVMng1N21kbitXM3U2YUJCVUZqMHBmbDFzU1VKd2Zs?= =?utf-8?B?S002TjZkMjZZLzd6czFub2N2RzhnRGdkdmRlTStmMjFVbStxNlAwUGNpUzB0?= =?utf-8?B?UHFKWm9NaHdDc2twUUJueG0xMXJRbVhZOHRBWEloVHlIMDlCSTNXWWw0eUVW?= =?utf-8?B?Rk9MK0lsK0FIdkFHOUJ5RDduVzFYdytTZVIySTl1bElURWlwUWdQNDZ3QUZH?= =?utf-8?B?TWExMkoyZFVTcXhIL0lkNmRZcFhDMEl3bXZmWVJpV0JlTG1nbmFEUDd1bmo0?= =?utf-8?B?Rjhib0RBV0J1aDhzUzJyVHhZaXducVc4UE03emp6d1BUZmRuaUNIWFZsT25S?= =?utf-8?B?bkFhZWJwaC9MeCtWbkZ6K05KK0NxYXRMbURSdXZDemsvbTZWRlVpM0lIZ3ZO?= =?utf-8?B?RjVjSUM2VHkwSzhsZEJMbU12SlhVODE3ZzBQYjNra3QrV0dkS3YxeElkZ2xT?= =?utf-8?B?S01UMG5LMVdEYzcvZUhiQUgxRDQvTHE4cWNGb3E0YUNGU2hBWVJuWDhxTmJV?= =?utf-8?B?eTRRVy9uYlhlRkVMMXZ0S2laSHRqS2h3REFoei82d1YrOUhFRWFhRy9GNU5y?= =?utf-8?B?SXB5bGJMeWVQMHFuQk5yemJFL1k4Q3hHMFJZNU9SQ3hTcExFU25NRUlxVVFm?= =?utf-8?B?c0FucFRsT081WlB3d0J6anFhc3grL0dNTGdVMU9XODdhRHNPUDYrVFM4aUFT?= =?utf-8?B?STA4OUpGVlVaZzBEck0zaWdGTFl3ak04allyWTZyUDhkK1JxSlNGUTJPWEgw?= =?utf-8?B?bDIwTk5ZYncySjlrNElaUDIwUFFUTnhDK1Q5YW5FeU8vQWdMU0t5ZzN0cldV?= =?utf-8?B?L2JucGhsdytrSFIzRXFnTDZ4RUtFanZBL3YrUWdwVEt2MlJuZXlLTlE3THFP?= =?utf-8?B?TStHY2tJMFBjNHA0dS9FT3F2NkRwNXpiZTdjaFM2SHk5eUlLZUpmbG10dlNm?= =?utf-8?B?RkpRcVdKRVlTR3R0UUpxcUM5bEx6aG5BczVXZ1ZIT3JCa0xUckV6YTc1WE5L?= =?utf-8?B?UjU5ZGhYWFVjYllqeDBQeFY1REJMMlRVcktvRnpoNENuQjIzSHRtOHpnNm13?= =?utf-8?B?Q3lHQnlKcU81SW54UlZqeHVYeFJrTCtYc2ZUUWc4TGJtcFVxVStKOEVIWDly?= =?utf-8?B?YVRXdnJvckNKWkdkVmIxTEdEVE5yMWdCZzlIT0pNaHc2WlQyTy9rclVucldE?= =?utf-8?B?MEdFcEJIUVRQcG9CSTlqbHg1NkhUaFc1a2VadGJNdHo5L0JJeHZIZ3JhUXJJ?= =?utf-8?B?S3lyUWowT0taa1RJOGhTZ3IyS3c2RnBWL1laVDhsRi95am5nYmJKZkFnVHZM?= =?utf-8?B?TVpCaTFnSmZWYjdHODZTRWZXRXhVZkxHY1ZVcUlST0tzRmZpMGlySXJVK1F6?= =?utf-8?B?Mzh1NGoycnExSnA5N1lHQnpES3dSaEJWM2RwTHNPTWU2NGdYK3ZyN0hpZHR4?= =?utf-8?B?QnlyQ0MzMFB1OGFHcjY3MVFQemJVSHNkL29XV2tBQUNSVitJYlFWN1dNUldI?= =?utf-8?B?d2pqSGdDTGxob0VnYTNFNy9wOVRCWnkyNHlORjBVRUFkUHd1MzUzK0xsMTdV?= =?utf-8?B?RFZPak90bkdPS3NjMzUxMVdTcUJaTFE3djhQNnNieGlBaWFmTW5rdUFLbmpV?= =?utf-8?B?dTJ2Y05WZUEyclRFWitkT2E3clNRR1MwcC9hTzVMenEzQndFWTNFNlpyUlp1?= =?utf-8?B?aldpdWFKM01ncjd5Sit1ckoyazc3Y2p1MzNoaHZxUEh5QjdJTlpOSGNpbU0y?= =?utf-8?B?UElscFJNUDRmYTV5cUNFamZhd0NDRDdEWXF1Kzg3eHlCNHE4dVp6ME5naWp3?= =?utf-8?B?VlQxNjJCa05lc0NucVVMWW1UWDBSN2hRSXFKMC83U0I0ZFlIVlErS2VRNFVJ?= =?utf-8?B?TjhVeXVLUkJDVllMalA4Y1lFSTJNRG9uT25GTncyTFd3aUJ4dGZMZUE0NWww?= =?utf-8?Q?dOmE6u2qyrEdnITjrlW4Xms9g?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: a56a3be6-af81-4976-5b38-08daf32e6c02 X-MS-Exchange-CrossTenant-AuthSource: DM4PR12MB5229.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Jan 2023 17:16:33.4672 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: sMDbQGpkhhKucKxUM4xa3RV9sEUEgQHCvcKJNpgo9/QucfvPf3Dh46aJ2uPZEiIZ4wu14G2pUTB4bgmLbqS0rA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SJ0PR12MB6853 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/10/23 10:44, Peter Gonda wrote: >>> >>> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c >>> index 273cba809328..9451de72f917 100644 >>> --- a/arch/x86/kvm/svm/sev.c >>> +++ b/arch/x86/kvm/svm/sev.c >>> @@ -1294,7 +1294,7 @@ static int sev_send_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp) >>> >>> /* Check if we are crossing the page boundary */ >>> offset = params.guest_uaddr & (PAGE_SIZE - 1); >>> - if ((params.guest_len + offset > PAGE_SIZE)) >>> + if (params.guest_len > PAGE_SIZE || (params.guest_len + offset > PAGE_SIZE)) >> >> I see the original if statement had double parentheses, which looks >> strange. Should this if (and the one below) be: >> >> if (params.guest_len > PAGE_SIZE || (params.guest_len + offset) > PAGE_SIZE) > > Isn't the order of operations here: '+' and then '>'. So is the patch > correct and matches the old conditional? I am fine adding additional But what was the purpose of them in the old conditional? They weren't necessary. But, yes, that order of operations is correct and those are both before '||'. So the extra parentheses around the second condition check are still strange then, right? Given that, then: if (params.guest_len > PAGE_SIZE || params.guest_len + offset > PAGE_SIZE) > () for clarity though. I do like the look and clarity of the parentheses around the addition. Thanks, Tom