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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Matthias Brugger , AngeloGioacchino Del Regno , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH][next] wifi: mt76: Replace zero-length array with flexible-array member Message-ID: References: Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: AM0PR07CA0027.eurprd07.prod.outlook.com (2603:10a6:208:ac::40) To PH0PR13MB4842.namprd13.prod.outlook.com (2603:10b6:510:78::6) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH0PR13MB4842:EE_|DM6PR13MB4035:EE_ X-MS-Office365-Filtering-Correlation-Id: fbe5588d-2766-4af0-ca99-08db3f36e95e X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; 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:PH0PR13MB4842.namprd13.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230028)(4636009)(39830400003)(346002)(136003)(396003)(366004)(376002)(451199021)(38100700002)(8676002)(8936002)(44832011)(5660300002)(7416002)(2906002)(36756003)(86362001)(478600001)(6486002)(6666004)(54906003)(186003)(2616005)(966005)(6506007)(6512007)(53546011)(66946007)(66476007)(83380400001)(316002)(41300700001)(4326008)(6916009)(66556008)(2004002);DIR:OUT;SFP:1102; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?2rjRF4mML/xCcYkqyA6AItClbUWsW7hGIIbHkBSraLngFIN2Tz3E4+MoNCDH?= =?us-ascii?Q?RRNphXkfq6fGlbLvOXczm0xwPKp0tBNceUNGHPalgFZkQ6BxVWzR+E85W5bv?= =?us-ascii?Q?quzK8U2Zk4eqqvX3X33YeZW3HM0czoVnDjZ2RAxGdJibjZudkXsEMVei2vcB?= =?us-ascii?Q?MyfxMAQxK50mc00A/l200zRxN8iLR3d4pgrC9Jb9+ZxMAEsgTYuZQaTyRIo/?= =?us-ascii?Q?VnISAIAguRy2nkAj4J5h3JaYGsRw9hKL0wj2f3iWTT9FGSK+IUACfYAlAIC1?= =?us-ascii?Q?khcdh8uh3V1SIEWp+v6T3qucZU3npFx9hhoi/vYY1f0YSCn+o04G9G7iYWMX?= =?us-ascii?Q?81pdeKi53XE1g05KhOPmKawz59sFeOX56jAeweFawKg5S15nwHEKJlOJzH1n?= =?us-ascii?Q?9fjrtoPYKKyiSVjg+6D8wwCyfwX499DitNpPFrEfIJTC3/Cd4J5fdEewIb7X?= =?us-ascii?Q?sYpFIoMeOH8adrEYMXcRlfkG4BAT3KEa56rOgQrK00mBJqHwRkuHu+0VSaOB?= =?us-ascii?Q?q7EFavT8XNfxQTOoDuycsXUc6GeQw80zwlgsSI01yRaylm8Nv+26s7O98AXS?= =?us-ascii?Q?DuQ+wnqAwL0zBWOxP8+WLjMlSp3TnrHMUhyYuOGH33L51weW5alKMWNcDNSM?= =?us-ascii?Q?e8cmGOvTWLNnxVdarZF7kCuoQWzdv+g3yF2xt/Z86MzHLEjP7oVI9HWkNq70?= =?us-ascii?Q?xvGL5vHOZ6OgXZpGqqaIYZJISDD0XKyKyrihl3VVH7sinq5JDRpKztXITVTb?= =?us-ascii?Q?nEWJqvb3TC2HQ9WWtPYdYojRZ7qdanfY5Lut30vtHLbVq+dmpZFdPnjV0+VW?= =?us-ascii?Q?kvzNN0rWz5Rk1yD3eN/hkLMlLl07tjfT+YQm0dqUXYJZRKz0NrXTg4F0Hpwq?= =?us-ascii?Q?2h303aF+FXx2o5rzCMbMjmPhW/c5jOGsJpuqL4wuz4mxaTPL5/7nSiKaWFJy?= =?us-ascii?Q?wFS29TNCISDhcPJhYDUMssyNzJWeqDM8eskBW2xqx7QkbLe2sXXYcR2OAwCb?= =?us-ascii?Q?wrEUjFII1c4aCdWe6L67OVSP7hhDucKFRlx7i8j11fCt1m8c1RiP95KZze9p?= =?us-ascii?Q?3pzAe+NjG46tJb8DWnpTJlQDNUxj2ojdhsh3yg+MucoJVGALwv5m4MgAg4WS?= =?us-ascii?Q?PZZa3b1prdV/TzahVuDyRDoBYwQsRBueYSbeVYjXJOivRMjRJPGvmxnxoWR1?= =?us-ascii?Q?bqZo9rUbKYVyPbLqRLe6ASNiHNVCOJl/zRnvpL3kMRel2Bw+G2Z7fpARiOuw?= =?us-ascii?Q?0zuBJ51vj+1lri1uHGIqLFXODN21VKfJQXUnexbqK783ZhySJ7HdwlFybzK3?= =?us-ascii?Q?GD28kILGxaBBiM7J3wI8DvzVCty3ixOP2kszHo4+MRlFpd6WywWQXFvxb/eI?= =?us-ascii?Q?0frC23NP4dpAdwRgfRgpTFt7ILc5zjXBEJToR/cXx7H9h9LjrGXy/fxzP1Uj?= =?us-ascii?Q?ODPqX+gCvTXqx2qiTLqoqm+widsgY1mjJo36qE0BiImfFv66qFDyNVZ+yky0?= =?us-ascii?Q?mkoHGN3qTu0Sp4fbOVveoU8ElukNNZqI6dQ4C6MuW8xwnQP47dxO5hxJIM9X?= =?us-ascii?Q?uCvAIM8qlSe6PViMtW4wpbPX59jxzoAGeQdVH7gzXYgtLd0M9z3aOBjiajMV?= =?us-ascii?Q?8jinLxfOI/L+ctaI+ulaFvNSbYysoK3JSe7mQEpGuQrgvcevW5lCq4YRdLpZ?= =?us-ascii?Q?U+OiEQ=3D=3D?= X-OriginatorOrg: corigine.com X-MS-Exchange-CrossTenant-Network-Message-Id: fbe5588d-2766-4af0-ca99-08db3f36e95e X-MS-Exchange-CrossTenant-AuthSource: PH0PR13MB4842.namprd13.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 17 Apr 2023 11:28:48.2452 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: fe128f2c-073b-4c20-818e-7246a585940c X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: XRAjZ6crE6wFleHfwHJdK3nOz/lRr0netlVeVqJlPbhUleA2+gp70rZTtiugDCMwVt5fHONUNpgnQGOMnUtWbNQ9v1oyu+7zXGetCsLs+po= X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR13MB4035 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Apr 11, 2023 at 12:39:06PM -0600, Gustavo A. R. Silva wrote: > [You don't often get email from gustavo@embeddedor.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ] > > On 4/7/23 01:23, Simon Horman wrote: > > On Thu, Apr 06, 2023 at 08:32:12AM -0600, Gustavo A. R. Silva wrote: > > > Zero-length arrays are deprecated [1] and have to be replaced by C99 > > > flexible-array members. > > > > > > This helps with the ongoing efforts to tighten the FORTIFY_SOURCE routines > > > on memcpy() and help to make progress towards globally enabling > > > -fstrict-flex-arrays=3 [2] > > > > > > Link: https://github.com/KSPP/linux/issues/78 [1] > > > Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [2] > > > Signed-off-by: Gustavo A. R. Silva > > > > Reviewed-by: Simon Horman > > Thanks :) > > > > > > --- > > > drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.h | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.h b/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.h > > > index a5e6ee4daf92..9bf4b4199ee3 100644 > > > --- a/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.h > > > +++ b/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.h > > > @@ -127,7 +127,7 @@ struct mt76_connac2_mcu_rxd { > > > u8 rsv1[2]; > > > u8 s2d_index; > > > > > > - u8 tlv[0]; > > > + u8 tlv[]; > > > }; > > > > > > struct mt76_connac2_patch_hdr { > > > > Curiously -fstrict-flex-arrays=3 didn't flag this one in my environment, > > Ubuntu Lunar. > > Yep; that's why I didn't include any warning message in the changelog text > this time. > > And the reason for that is that tlv is not being indexed anywhere in the > code. However, it's being used in the pointer arithmetic operation below: > > drivers/net/wireless/mediatek/mt76/mt7921/mcu.c: > 164 rxd = (struct mt76_connac2_mcu_rxd *)skb->data; > 165 grant = (struct mt7921_roc_grant_tlv *)(rxd->tlv + 4); > > > which means that it can be considered as an array of size greater than zero > at some point. Hence, it should be transformed into a C99 flexible array. Understood, thanks for the explanation. > > gcc-13 --version > > gcc-13 (Ubuntu 13-20230320-1ubuntu1) 13.0.1 20230320 (experimental) [master r13-6759-g5194ad1958c] > > Copyright (C) 2023 Free Software Foundation, Inc. > > This is free software; see the source for copying conditions. There is NO > > warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. > > > > I did, however, notice some other problems reported by gcc-13 with > > -fstrict-flex-arrays=3 in drivers/net/wireless/mediatek/mt76 > > when run against net-next wireless. I've listed them in diff format below. > > > > Are these on your radar too? > > Yep; those are being addressed here: > > https://lore.kernel.org/linux-hardening/ZBTUB%2FkJYQxq%2F6Cj@work/ Thanks, I had forgotten about that.