Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:3 as permitted sender) client-ip=2620:137:e000::3:3;
Message-ID: <c3124377-a045-6458-fc10-f0096fa736e4@amd.com>
Date:   Mon, 25 Sep 2023 08:35:40 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.15.1
Subject: Re: [PATCH] drm/amd: Fix the size of a buffer in
 amdgpu_vcn_idle_work_handler()
Content-Language: en-US
To:     Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        Alex Deucher <alexander.deucher@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Lijo Lazar <lijo.lazar@amd.com>,
        Mario Limonciello <mario.limonciello@amd.com>
Cc:     linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
        amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
References: <d8a9cda0c4c391458ddd63d1be88f2a757f6a5d0.1695410820.git.christophe.jaillet@wanadoo.fr>
From:   =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>
In-Reply-To: <d8a9cda0c4c391458ddd63d1be88f2a757f6a5d0.1695410820.git.christophe.jaillet@wanadoo.fr>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?OFFUUWFhSWFmV1hiUXlMQVhuRmNiT2c5QW8rMytySFZveDYzLzVvT29TQk5n?=
 =?utf-8?B?T2lrRE01WklJV2Qzb3BnamlXenhLRFVXM3owbjZHYzBzMVJ1SnZSQk1SMUFm?=
 =?utf-8?B?YzVxWHhTYTZMelJrRVo1UHQxRnR5N3VQL3VYU1paem1kbFdKNDlMQUtxTkJR?=
 =?utf-8?B?c0ZJb3htUDF2TTJ0cDBoU2twQm1Cek5rOTlqWlY2Sk1WZ2oxWUFLWDIxMWYw?=
 =?utf-8?B?VitYeTV3UDJ3bTl1Wjd5TU9sSDJtbll1dmFObElGM0tQa2U4cmRHbk5QSDQv?=
 =?utf-8?B?RGlaVm9zdFZFK0sveStLOEhySHVySkpBeHVYMGNQNWQzZ1dnWGxVYkU1Y0o4?=
 =?utf-8?B?bEJjd0RETnNVMThBTWR4WEhOR3RMQ0U0TFRoV3JIWmZzTlZ4eC9uMzV1VzZZ?=
 =?utf-8?B?cHVtSHhybFF5MzZ6dHN5dkRadEIzWmMxNWNpRVJmUWdSamg2S0xETE4xWmNk?=
 =?utf-8?B?dStaZHY5bVdWQmJDUkVJSklqeGp0TExIbU5BeFJhbU9qTlhObWVmbUVnV2sx?=
 =?utf-8?B?allQWVFjcmZXSmZpWDNLUUVGQkY2RllDeWNuckN2UzJOZlRSTTlsNHgvTi9i?=
 =?utf-8?B?SzVTbGd2RzJVMEtRcFVkRmFWbXo2K3lKVklwSGNxU1pxRGVQMkVXN2IzWnpR?=
 =?utf-8?B?UE4yRjNFZ1JjMEJEVDEva3I0K01jWEx1SVlYakZSaGVBVzNnWDJpVzFQTVNB?=
 =?utf-8?B?NHJpTFMxZ0dwRVFYYW9KczlaMWlKV2xmLzZKSzlWNTlzVit3cnhSZXNrRjRR?=
 =?utf-8?B?dW1oa1hzWXJkWmdwMjV3bWdNUHI5TDJjd1p1SXdpdk5uZ1U1LzZ6N0xMTmtU?=
 =?utf-8?B?M3JvZGppTU5DdXhqUVZ0NTFsMndTTERlUWhTcnBrUWtNY2Z5SW5JTEdLcTdS?=
 =?utf-8?B?ZkM2N2VLLzU1WmVwQjlEczhQdlNORlRTank0MWk4VFFJR3NyTHNZRkdPRjFx?=
 =?utf-8?B?V0VLT0RvT2NMbEhDcWdNbXdOS21CQVBjbzJtVGVBUTdhdnJVb2xkM005VzBR?=
 =?utf-8?B?VTl3LzF4M0k2eWpFV244cmFsZkdtL05LYVZpNlVmTEREeG82WkNVM2VDbEFN?=
 =?utf-8?B?N1FHTzQvMzVPa1o3dUkzcElSYXo3TncreVlmdmpOMkV4K0VRbEs4cG5mSmlh?=
 =?utf-8?B?SE02elordVVYSjBaL1BPMURCaTh1NkZqdHBSamFydExQVWhNNlVZdXV1ZndY?=
 =?utf-8?B?aEs3VmQ3UkNkekZPWWZUN3VCZkFqU3kweXNVdWhtSVNlSkxHSHFYQUhoSGhB?=
 =?utf-8?B?YnZVdkRKd1N5ZE5RMHVNYStTekk5UXRKT05sU09wTGhHQjBsYS91UXhlcGFq?=
 =?utf-8?B?ZTNoL085cE9weEw0dkp6MExNcnRWbzlnbERZT3FVeUptL29sZFN5eDVHT0oy?=
 =?utf-8?B?Y0t1ZjQrTU5pZU5DTUVmdUs1cTVJWnIxR3ZoN3llRjd0TTcvZ045MnUzSTNH?=
 =?utf-8?B?Ny9WaEhHTGpINVUzclVjWjk0VGRId0d4WGYyUnYyeTg1bmRLbzg0cnZIU0pO?=
 =?utf-8?B?RWVaRklvbnNtNi9DL05vRWNtZDdsZ2xzNkJXWVVneEcrWVZWR0g2K09vTVEr?=
 =?utf-8?B?OHZTa0c3ODZGMVV2bHJXei9mdkVNckZmdjRPUm9MZkVSYmFGRlRFNi9TbUlj?=
 =?utf-8?B?d3QwclpNZDEzNVRBeUMrb0J6K1RnejNIZXdMeWw3WnhndGtRNGZuOUJJT3Rn?=
 =?utf-8?B?eXdVeW1FK3VZR2cya3Y5YW9HN1UwRm9QZ09ZeVNzNnlKYnVwbFpGbWxxUVk1?=
 =?utf-8?B?elJZajU5U2JjK3p1bzN0bXBSQXcxVTlETTZmSXdXK2FEOE05SXYrWlFJVElQ?=
 =?utf-8?B?Yk9ud1N6UDRWOXhWZzRJYTNHMUpVemdSaDZ0K2NEMmp4ZFZ6NmxVNERqa3lX?=
 =?utf-8?B?Y1g5Tm1pSHpOUHU4QUdCQXlmRTk1SDFCRWszcENVWWdZRkZlUDZyR3Y0Y0dT?=
 =?utf-8?B?WVl4NEdScmNzUE5QRkhRb0FhajdXMTdVeTFtVXcwVHZyYUJCR3FxalJxUmdF?=
 =?utf-8?B?OEJKSHRtcURIR1pRUzVlMzdKc0l5VVArNk5jRUpQZWFlMlcrSndCZGFUckxr?=
 =?utf-8?B?bXZucDgxVTRwRXZ4MzV2ZEoycWJaMktrMVp3UGwxeFVlOXdYMUk1dE5SN3B2?=
 =?utf-8?Q?Po8Dk1EeLkzAInp6AtrzIX5Od?=
X-OriginatorOrg: amd.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 155c0234-25c2-48a6-277e-08dbbd91a6c0
X-MS-Exchange-CrossTenant-AuthSource: BN8PR12MB3587.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 25 Sep 2023 06:35:46.9524
 (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: qYJXWPV5lozs0ZD/Z5o2Qv24AY9Xsi7Aj1DDhvyRn9kGMj2ZSqf3GPXB0FQA5hnU
X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR12MB5401
X-Spam-Status: No, score=-2.3 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED,
	DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,
	MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS
	autolearn=unavailable autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lipwig.vger.email
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 (lipwig.vger.email [0.0.0.0]); Sun, 24 Sep 2023 23:36:31 -0700 (PDT)

Am 22.09.23 um 21:27 schrieb Christophe JAILLET:
> In order to be sure that fw_name is not truncated, this buffer should be
> at least 41 bytes long.
>
> Let the compiler compute the correct length by itself.
>
> When building with W=1, this fixes the following warnings:
>
>    drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c: In function ‘amdgpu_vcn_early_init’:
>    drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c:95:58: error: ‘snprintf’ output may be truncated before the last format character [-Werror=format-truncation=]
>       95 |         snprintf(fw_name, sizeof(fw_name), "amdgpu/%s.bin", ucode_prefix);
>          |                                                          ^
>    drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c:95:9: note: ‘snprintf’ output between 12 and 41 bytes into a destination of size 40
>       95 |         snprintf(fw_name, sizeof(fw_name), "amdgpu/%s.bin", ucode_prefix);
>          |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Fixes: 69939009bde7 ("drm/amd: Load VCN microcode during early_init")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
> index c93f3a4c0e31..f8cd55a0d1f0 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c
> @@ -88,7 +88,7 @@ static void amdgpu_vcn_idle_work_handler(struct work_struct *work);
>   int amdgpu_vcn_early_init(struct amdgpu_device *adev)
>   {
>   	char ucode_prefix[30];
> -	char fw_name[40];
> +	char fw_name[sizeof(ucode_prefix) + sizeof("amdgpu/.bin") - 1];

When that string constant is used multiple times it should probably be a 
constant.

But I think this patch is superfluous to begin with because the 
ucode_prefix is never fully used.

What we should probably rather to is to define some 
AMDGPU_MAX_UCODE_LENGTH and use that instead.

Regards,
Christian.

>   	int r;
>   
>   	amdgpu_ucode_ip_version_decode(adev, UVD_HWIP, ucode_prefix, sizeof(ucode_prefix));