Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:7 as permitted sender) client-ip=2620:137:e000::3:7;
Message-ID: <55e07c56-da57-41aa-bc96-e446fad24276@intel.com>
Date:   Wed, 15 Nov 2023 16:39:27 +0100
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH iwl-next] i40e: Use correct buffer size
Content-Language: en-US
To:     Kunwu Chan <chentao@kylinos.cn>
CC:     <horms@kernel.org>, <anthony.l.nguyen@intel.com>,
        <davem@davemloft.net>, <edumazet@google.com>,
        <intel-wired-lan@lists.osuosl.org>, <jeffrey.t.kirsher@intel.com>,
        <jesse.brandeburg@intel.com>, <kuba@kernel.org>,
        <kunwu.chan@hotmail.com>, <linux-kernel@vger.kernel.org>,
        <netdev@vger.kernel.org>, <pabeni@redhat.com>,
        <shannon.nelson@amd.com>
References: <20231113093112.GL705326@kernel.org>
 <20231115031444.33381-1-chentao@kylinos.cn>
From:   Alexander Lobakin <aleksander.lobakin@intel.com>
In-Reply-To: <20231115031444.33381-1-chentao@kylinos.cn>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?SFc3UU5pVkJXUlRyOHhuem5vNXhneXpKWnhpaEV4eWJEMVlmbkNWWkIraEhw?=
 =?utf-8?B?V1BTNFdCdFpmM0MyVVlnK2ZmLzljLzZLSG9EOVpjWHpiZmhwRExraksyV3h4?=
 =?utf-8?B?cnZsTzJtT3RiZzRJM05IaWdZUXArdEdhdk1ZWlVqcW53MWk3T3QzUmp4cUhQ?=
 =?utf-8?B?bTZkY0c3OGF1aHhZUC9MTUIyTDN2TDhzMmtsTlZFS0ZRdGt3QjlLRXNSZDNE?=
 =?utf-8?B?eEEvZ0tGdnEwM0NIMHhUYTNGRGVBZFpSZFVQWlR5M1R3VHY0RFVyeXVRSDE5?=
 =?utf-8?B?Yys5SHJodXJ2V0Y0K253UEVDN2t5bmlyOURVelBxLzBEbGt0bFZ4RTQ0cjF0?=
 =?utf-8?B?cGFpclFWLyt5d0lZaWs2Z1dzeDViK0ltMlFsSVJLZ0RCcFoxMnpsUm9tTUgx?=
 =?utf-8?B?emhIVVkzUERCS0hwZjdEMTkvSGhKeVAyVEpJSXd5MmQ0MXFNUkQ3aDZIVzht?=
 =?utf-8?B?Y1R1c1ZXTFpkRUUzNmVOdW1lbUR4YUlKT0RWZGd5U0p4RTNWWnVVam5kQlR6?=
 =?utf-8?B?YklyQ1o4ZUpPUDRRdkR4OXloMmVSdTl2Q05CVE1Ya0J6a2s5YVFVSk0razlk?=
 =?utf-8?B?cFQ5SU1jMlZrekpWSmNGSGMxMmhndENuS3NpRURjWUQ4NzJmblBTTHRQM096?=
 =?utf-8?B?SXd5ckkzL1hrUE4yUUtBajBtQ3Z6MncwU0JuVWZ4SVdjLzMyeDhVczNsOUxh?=
 =?utf-8?B?WWxtdTc2cGNLTHRDM1VDd3Y1eFlpYzk3dlJ3ZXlMS09nZkhxTkw2eThOQ1d2?=
 =?utf-8?B?dWttNmRiS2NQTWVBOUNUckFDb3QxbjJYeG1zRzdiaXFDQmV5M29oTVErM2gr?=
 =?utf-8?B?QjNaVnJHVy9LbUI3NjF3aUxqeFJPazdRVG1pWnl0Vkh3bmhsRFpPcE15WFVU?=
 =?utf-8?B?U0Zvbk5LTWVMSWc2OEJpeEZGZ1lBaExLQXJyRC9SMVBhcHJDNmZGd2JmV244?=
 =?utf-8?B?azJ5aVRMU24wMDB2eGFMOHN2OUZaQTBMVllqRWQ0c3gxNGh6cHZJNmZSVzMx?=
 =?utf-8?B?cHhUZXk4QnkvaGFhcURtT1p1Qjg3bURXTTZpQ1NjbTNuSmRpcWFxTjhHUXJw?=
 =?utf-8?B?Q25nSE43NkZSM214L1lNTlNVZnlSRzlVNEdxbXZ4NkNUWk5wWCtmZm5FR1lB?=
 =?utf-8?B?eTdLbGhHTC9kUWJiM3EzbWRlbjlsbDlpVXRnUDdnUit2KzdKcmJtVnVRcG4w?=
 =?utf-8?B?Y0NmZ2xzOXlteEdLZU1WOGttWEY0aFYwTmVjYmtaa3JEd0tLcWlzTDRBRGQ5?=
 =?utf-8?B?QXhKMk1na2FTdkdEVjhGQm5sdmRyZTRRNUJZT0h3L2ExSzJOMEdTdTdNWHd4?=
 =?utf-8?B?ZzhheVFvRk1VTm1jaUNrWXRqekQ3RWdKS3NCR2pJRHJvTUx3bkc4WFpTbC9w?=
 =?utf-8?B?ZUV6L2pIejNqajdOWXd5bFFjNU5XY1NoSDF4SGFRV0lROFY0a0xHNEFiMWhI?=
 =?utf-8?B?Q3BMTitFOFdIOE5jZ3FveFFnTUExWDBUeXVLSGV0L2xkVXZpM3o0OGltTEo5?=
 =?utf-8?B?bmpsNkdpcS83UVJnaUNrRm5hYXd5S2tYZUk0TXUwRXhDdEdlWEhOSWR4Q21Q?=
 =?utf-8?B?TThZTUJINkRHOXliaTBQK3VJT0piRjcyZlhjOE5zKzViODhkOHNaUCtMa1JF?=
 =?utf-8?B?ZGtPa2ZwT2J6MlhwOWtod2JDcFdRZjFhOGJYUEJaRFpNNlJDU3hYQm5TOXE4?=
 =?utf-8?B?VzJkckd3MnhIZUZ5bkdrdWFlY1pzSEtkandKZ0xIK1hpTFo0QjBkd2NXVFZN?=
 =?utf-8?B?aFpnYmtzbEMzZ0VQTzJiMnUxaG1VeGVlR2JsaGFsNWJ0RWNDR2FUU3UrMkJZ?=
 =?utf-8?B?citHWkFwM3VwWlo5eE1mZksxNGd5cFBIMTdGZk96dXRnM0dIVnE1OVh2ZXY1?=
 =?utf-8?B?bERsYXcrWFlabW9nZDN1cm1xRzM2cHhBM2MzNnd0cFliMHh0TmN3RitxVnBO?=
 =?utf-8?B?WFRnc2ZJam9HV2M0UVcrdlkzYkJ6cDJpS1hZeUZYMGVWQy8yaDlBK1NGUjBq?=
 =?utf-8?B?Q3V3RkhqZXZXc2dXbnd0aFNHdTFFUzI3eHV6UU8rR0VQalRpeFpIL1dRTnBV?=
 =?utf-8?B?b292eHRaV1BQaFA3S20vRDVKUUp3U3pnV0NvREdXbjY1UHBNUVN5M1NwbWNJ?=
 =?utf-8?B?dkMxQUpPbi9lQjdHa1VJN0NyQ0wzd0ZLam55QUdWSFJoOUg4dlhTRm4rMFc2?=
 =?utf-8?B?MHc9PQ==?=
X-MS-Exchange-CrossTenant-Network-Message-Id: 9ac010ab-2e6f-41f8-9cac-08dbe5f11af3
X-MS-Exchange-CrossTenant-AuthSource: DM6PR11MB3625.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Nov 2023 15:39:50.7485
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: RtupuzHn03DNXZLp10D6awjbZmjrtHR2VKFORTOmNMK9yzbW9ajfKlMUIqwr8XBOGaEdE6xOCG+X7MFPpVBP2v8znVOqHEKfge6NTeDR6Bc=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL3PR11MB6364
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=-4.5 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,
        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
X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (snail.vger.email [0.0.0.0]); Wed, 15 Nov 2023 07:40:03 -0800 (PST)

From: Kunwu Chan <chentao@kylinos.cn>
Date: Wed, 15 Nov 2023 11:14:44 +0800

> The size of "i40e_dbg_command_buf" is 256, the size of "name"
> depends on "IFNAMSIZ", plus a null character and format size,
> the total size is more than 256, fix it.
> 
> Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
> Suggested-by: Simon Horman <horms@kernel.org>
> ---
>  drivers/net/ethernet/intel/i40e/i40e_debugfs.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_debugfs.c b/drivers/net/ethernet/intel/i40e/i40e_debugfs.c
> index 999c9708def5..e3b939c67cfe 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_debugfs.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_debugfs.c
> @@ -72,7 +72,7 @@ static ssize_t i40e_dbg_command_read(struct file *filp, char __user *buffer,
>  {
>  	struct i40e_pf *pf = filp->private_data;
>  	int bytes_not_copied;
> -	int buf_size = 256;
> +	int buf_size = IFNAMSIZ + sizeof(i40e_dbg_command_buf) + 4;

Reverse Christmas Tree style? Should be the first one in the declaration
list.

>  	char *buf;
>  	int len;

You can fix it in a different way. Given that there's a kzalloc() either
way, why not allocate the precise required amount of bytes by using
kasprintf() instead of kzalloc() + snprintf()? You wouldn't need to
calculate any buffer sizes etc. this way.

Thanks,
Olek