From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=pass header.oldest-pass=0 smtp.remote-ip=52.101.43.2 ARC-Seal: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=pass; t=1792578389; b=c0zSLIu1WG02Nrjk1mhj6EwvyNww1eXbB04vJtIyXLVLB9AnezeAcqL6dqSzcGpqlzw4 Sgsmex+vcEoIs/xUhd8Ifmz1T62uZnecYm+MJpx0jOm3nWO7bA1vOZaKAbUruiEBuNq0l UXhPCVYOZmRWA0hGVMuAulR10HHSFjVsX1GQgdIlE85Yp1Wihx4BrrBiwpIyGkqifbgdx LIzzehY8Aa9rnkfHxidAUEMsfSx/pzA3Dbudr9AINkQhjAm+9+DZEzsMFzbTDytmjHTtd K5RtXCepLCNEwFh2q3WDkp7n7IG918b0/T6mcnnfiFZYHam2oPuque3DJ4m1Zx/AluQ== ARC-Message-Signature: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792578389; h=DMARC-Filter:DKIM-Signature:Received:Received:Date:From:To:Cc: Subject:Message-ID:References:Content-Type:Content-Disposition: In-Reply-To:X-ClientProxiedBy:MIME-Version:X-MS-PublicTrafficType: X-MS-TrafficTypeDiagnostic:X-MS-Office365-Filtering-Correlation-Id: X-MS-Exchange-SenderADCheck:X-MS-Exchange-AntiSpam-Relay: X-Microsoft-Antispam:X-Microsoft-Antispam-Message-Info: X-Forefront-Antispam-Report: X-MS-Exchange-AntiSpam-MessageData-ChunkCount: X-MS-Exchange-AntiSpam-MessageData-0:X-OriginatorOrg: X-MS-Exchange-CrossTenant-Network-Message-Id: X-MS-Exchange-CrossTenant-AuthSource:X-MS-Exchange-CrossTenant-AuthAs: X-MS-Exchange-CrossTenant-OriginalArrivalTime: X-MS-Exchange-CrossTenant-FromEntityHeader: X-MS-Exchange-CrossTenant-Id:X-MS-Exchange-CrossTenant-MailboxType: X-MS-Exchange-CrossTenant-UserPrincipalName: X-MS-Exchange-Transport-CrossTenantHeadersStamped; bh=37khzORTcGvuIU86cexVxhangll/dY5I50ZEUw/15eE=; b=vHXwogOL+oto37KzZ4dFQvqHSJvx4BUQARTDRdjQTP3pTuw74zdnVnoIK4w2XwmvXr3f Uux6t2rq7a4qzpkcmQiOeQXWet8+HxcMsqRLCs59scnASvUmZNOWM8kqkkWRg6NPgvpHY 7xm+mW37ugHdSxYYF4ch6MtLFHxXctCmWJapq0+NxBW/S52fgN2A2Kwtmji6v2oqPUQ+y udYqi0vSjQAbk1YlvrRqOEb1hWguu8B4ThYW5LweMyAO2k8KvV9/JI3ZBA7Q0kFEzc+gS aK8dkCSKDuojNmBTh57IRid2b1Wis/6TXBOw/ccgMoMPo80/wlap4KLeqMPmeSrL9ZQ== ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=pass header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass header.d=Nvidia.com header.i=@Nvidia.com header.a=rsa-sha256 header.s=selector2 header.b="OAvGjDQ/"; arc=pass header.oldest-pass=0 smtp.remote-ip=52.101.43.2 Received: from SJ2PR03CU001.outbound.protection.outlook.com (mail-westusazon11012002.outbound.protection.outlook.com [52.101.43.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (secp384r1) server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8ABD9606A32F; Wed, 21 Oct 2026 10:26:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 8ABD9606A32F Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=Nvidia.com header.i=@Nvidia.com header.a=rsa-sha256 header.s=selector2 header.b=OAvGjDQ/ ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=hcIc0UNRxJXpabEnIzQaC++V2Zdn+QEX6NTJbDo3MBaQL1nKI9y6vb9TiIw1HustrB63+foYZiN6SPxORJLyzQwtp/jRrN7x6ShQwmC0wdQkWxjqCTjebQJw6EQrsSdo0mh1hiFmLhV/K/Ssp14TdVicBMkyNhZJmAoRClH27YulTWpiQuCQJCKdAMMr8sCJ5ajAstK/NEI+IXCFHEJbrxvO5LODsp4zzdr58Vx/b7bVNbRcKN5/hoCYOhKirvAiG3lUGIj7lywzCLLasSGsA6NJSfoNkx6M2fPY39hIKZb4eEUMdKDgbtQkRoWrJmu2/Xj5vfzRv1J/LFCP9MIolA== 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=37khzORTcGvuIU86cexVxhangll/dY5I50ZEUw/15eE=; b=woywUeMCr+j08HWwfC9Fc2eWE5RP/B8cfMSUQ27BiUYI2gGunezBE6luVMm/lajakMwdDISMQZTFGgaAC2v3fC2TCY9Zem47BmBUMJK2SzKFhf1BCWuV7JeBmhlRn69GanGq6h+CaXB2oCr1s4ycI4bGeRgPlcQ+C8eHLS0fJIgneg0BJD+evRfkzXwi3n0rqDcZrcGER2icfBljGpmI4O0rRHawE79Cvlh9IaQtrUwO+Y4pAoJInfWSjbFuDvzv+Da5tSJIRDPZclLa6TWYqeEvK361PQH0U2zbi6deTupfaRLhxodH7hKddCdIIj08ZxuvwqjSV+3iGSDkoetoZg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=37khzORTcGvuIU86cexVxhangll/dY5I50ZEUw/15eE=; b=OAvGjDQ/7jcr8HL4yIlsVqnK4P6mP5DODTSTemBH4HPhrGSwny3Pw4+TS3LzJPyzqTCWb5r8WVek0FnVqo33FM/X0hAxn++QeXqVVZLrNrx8brpE9bVKEOnVIV+8rDwiDdaksdp6TVXoSjdpCPiTquqUN0O+e5Z5+RP7hUGUyWtl4yr6393d/r4HrY5nMZ2unyFNwU4UrouEfqC4Z5a3ql6o5PsYUehVyZw8YTyhRDj+RCvpeLKsSAMIriysER7YKN68g9dw/9vQI05VPtcHof2nBI9tf91SqjGnOX37BBCCuTzsDAs2BSfESQDBqYgHNYhHfrvhhYpikY18bAEhKw== Authentication-Results: mx.microsoft.com 1; dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from PH0PR12MB7957.namprd12.prod.outlook.com (2603:10b6:510:281::22) by SA1PR12MB7344.namprd12.prod.outlook.com (2603:10b6:806:2b7::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.522.19; Wed, 21 Oct 2026 10:26:24 +0000 Received: from PH0PR12MB7957.namprd12.prod.outlook.com ([fe80::9251:acc2:cc63:3499]) by PH0PR12MB7957.namprd12.prod.outlook.com ([fe80::9251:acc2:cc63:3499%3]) with mapi id 15.21.0546.012; Wed, 21 Oct 2026 10:26:24 +0000 Date: Wed, 21 Oct 2026 13:26:14 +0300 From: Ido Schimmel To: Henry Martin Cc: "David S . Miller" , Jakub Kicinski , Eric Dumazet , Paolo Abeni , Andrew Lunn , Simon Horman , Kuniyuki Iwashima , Petr Machata , Ferruh Yigit , Antoine Tenart , Ilya Maximets , Seungwon Bae , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH net v2] vxlan: reject adding a remote to a nexthop fdb entry Message-ID: <20261021102614.GA3351287@shredder> References: <20261020034531.1420194-1-bsdhenrymartin@gmail.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261020034531.1420194-1-bsdhenrymartin@gmail.com> X-ClientProxiedBy: TL2P290CA0006.ISRP290.PROD.OUTLOOK.COM (2603:1096:950:2::6) To PH0PR12MB7957.namprd12.prod.outlook.com (2603:10b6:510:281::22) X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH0PR12MB7957:EE_|SA1PR12MB7344:EE_ X-MS-Office365-Filtering-Correlation-Id: 8fc0b53b-19e0-4777-2fa6-08df2f5dc1d1 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|23010399003|1800799024|366016|376014|7416014|11063799006|56012099006|10067099003|261009223027099003|22082099003|18002099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH0PR12MB7957.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(23010399003)(1800799024)(366016)(376014)(7416014)(11063799006)(56012099006)(10067099003)(261009223027099003)(22082099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?/x4ZeMSAjZ67f6+Fs6IvJGkLDcLPFYs48kUnV2pLbqrUfj/wiQjlGTtgckmX?= =?us-ascii?Q?me6bKiEFUjQnEI61WNJhb3maxKghcLa5KIYi1uQIkJBkmbCDp9AQZDZHTg7f?= =?us-ascii?Q?N0DLK3Csl4TVyB3o5ln0Bt1SZMJPtaHnpwtjKI2RVL46yM5llklAHVzwI3KW?= =?us-ascii?Q?x4nuogUC5kRHyH0nZpnml492ygu2p4VGkYs498ZL3mUT5TmmYchUb3r7Jwea?= =?us-ascii?Q?2HPxKMPTbJmTz/r9qMOcb48ELt3uezyo3K/ydUlct2zTcPJpibBvHL9kEhNv?= =?us-ascii?Q?UF1V/4aRNDr1wrO3/e811n4y0ej1+JPwyaCQxfzyXx2M1aYRVX5YCbk1k5dy?= =?us-ascii?Q?h711wVazawTCPvBb2gWyWPzWI9SSKVCE92nLanc0HLCPmCZe/H6yVZKXxsOs?= =?us-ascii?Q?RihxVCMSWqDcU+NmoBpz0GgiCoHRa/c6hg9AxXxZQ/awoehEjZaAy9pUgCel?= =?us-ascii?Q?PoIo6315ESPEfIIueEeps7aFjnODH0uR3uhAdky8p6P8Oqca9XRHd2TuVsyr?= =?us-ascii?Q?+4+0xH4bKjBzbirNv4JIU5+RDr7OpRdsEmYLOkS89ag5sao4QKjOissUEzxE?= =?us-ascii?Q?F7FbgDFSCeHUdVgM4P54o/QTDEcJvuZ58hSJW/Q1KBLqLCpgeGsQ5j8kAVm0?= =?us-ascii?Q?+39qYuIc/LgMJMM9ExGF+xiXHTAO+MFH6Rl1HeDNHLuFftNe+iLM/lS6YGtM?= =?us-ascii?Q?Cx5v72FkRUNrI6wegTk4JGleSAHD3eNDGP1BbTdIQz9b/imWXkQG/RA5iGvt?= =?us-ascii?Q?oCBzWdQqB6d72Pjldu7Vg4/p9c3fk7ZBg0HUy0CsAGa4ShLKAEbYfrUy7gng?= =?us-ascii?Q?5crBwte2N0mLdbY3vwToOkAwiSJqPbJKsuyIg/ctnxqtYlIDljrcRJ5emeTi?= =?us-ascii?Q?xpvrIkpl3akNkRflq0bZE7tRZlujWb/IdoEotBJBR9eGITrsgS6pd2kboXrA?= =?us-ascii?Q?VQz7pHNYVFqPuU19vALSbUtZeAvh7KIE1pyzIq/E/FcxDycO6biWSHWg1jtD?= =?us-ascii?Q?vbDMJ3WkfQojXF9gOTqV13lo8E50Kp6tskoSPpqkOhysv9GvoklTnzJq25+Q?= =?us-ascii?Q?L0Y6pY1DgZXPRv0UedlLKdcuWNvGaeZcVINdLmPbu1Hnuy8oYJSfngz4M7Pe?= =?us-ascii?Q?6HZuFeZ/9h6stUoavUTOGkDmrW9x3p6utR+DjWXDP+c2y3pEcbj5BxMvjQUh?= =?us-ascii?Q?uhR8n1jKiPCKs5ODBrPJzqrCgaZ94OAfGNr3rNg+8YGIXdUo3pfgaNrW8GRK?= =?us-ascii?Q?vxvLd+xAd01OIidUDPbL5d3I5H8pQITzNzm7W+8ieVn1dgjiYPBQGTqNIW4c?= =?us-ascii?Q?Kweh3FkNO5m8bDgAmp75elsqp6q6yZEuBmRq8FP/lIS1R8LFAMh3esW/+nHA?= =?us-ascii?Q?GWgGtZw4qbhi6s854AcCn1ZAsC+p3zt4Tm25Zkc98fZD7PFk66rrEX7X2FB7?= =?us-ascii?Q?vJurKIPWatx2ZoZky3/YTlsiZTodeB63J2aaZjWk2wLfEgvrQQVUJ+EsrqbQ?= =?us-ascii?Q?yGdyMBSNO2p5n94nmiJLUI0MS7l+PP7Ia27nDsFVD94FKIaCFStATkjCjTk8?= =?us-ascii?Q?6nUwC51o6lLFGngBGvbqqw0s84PGGFCP7cdR1jrF0Tcm7fQU3ykH+ETuSSZ9?= =?us-ascii?Q?jYzXxNrzuvgXAo+HxVsLirERDUDAyWky1/Y4ElTCIPLhQtKIVv33stTNQiXe?= =?us-ascii?Q?htWVFk730/U9PfZk9uzsxIUy/CzXOWmiTp7ma/wnIPg2dpgf?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 8fc0b53b-19e0-4777-2fa6-08df2f5dc1d1 X-MS-Exchange-CrossTenant-AuthSource: PH0PR12MB7957.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 21 Oct 2026 10:26:24.1185 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: Dj3zEM1pKiJYhwEtmvaIjle2cTzopl/LScS1mRoQv+XulbrjaB9qGZ6wwH6jpmhNnbM8onJqM4xwtInqrngF0A== X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA1PR12MB7344 On Tue, Oct 20, 2026 at 11:45:31AM +0800, Henry Martin wrote: > FDB entries backed by a nexthop group must not carry a remote > destination list. vxlan_fdb_update_existing() currently appends a > remote via vxlan_fdb_append() on an NLM_F_APPEND request with a > multicast or zero MAC even when the entry is backed by a nexthop, > breaking that invariant through three different callers: > > - "bridge fdb append" with a dst on a nexthop entry; > - "ip link set dev vx0 type vxlan remote " (vxlan_changelink()); > - "bridge vni add/change ... group " on a vnifilter device > (vxlan_update_default_fdb_entry()). > > All three reach the append block with nhid == 0 and a PERMANENT > state, so they pass the earlier nexthop checks. > > Reject the combination at the top of vxlan_fdb_update_existing(), > next to the existing nexthop guards, so a refused request has no > side effects: placing the check in the append block instead would > return -EOPNOTSUPP only after the entry state and flags have been > rewritten, skipping both the notification pass and the err_notify > rollback. > > Note the resulting behavior change for the two rtnetlink callers: > operations that previously succeeded while silently attaching an > unused remote to a nexthop entry now fail with extack > "Cannot add a remote to a nexthop fdb entry". > > This issue was discovered by Tencent CodeBuddy Security. > > Cc: stable@vger.kernel.org > Fixes: 1274e1cc4226 ("vxlan: ecmp support for mac fdb entries") > Signed-off-by: Henry Martin I agree that it doesn't make sense to append a remote to an FDB entry that points to a nexthop, but what are the consequences of allowing it? Does this patch fix a crash / memory leak? If so, the commit message should describe it. Otherwise, this looks like net-next material (currently closed). Also, please add a test case in fib_nexthops.sh, in a similar fashion to commit 98fc57d16744 ("vxlan: reject dynamic fdb entries that reference a nexthop id").