[PATCH] drm/amdgpu: Fix truncation by resizing ucode_prefix in imu_v12_0_init_microcode

[Lazar, Lijo]

On 5/7/2024 10:14 PM, Srinivasan Shanmugam wrote:
> This commit fixes potential truncation when writing the string _imu.bin
> into the fw_name buffer in the imu_v12_0_init_microcode function in the
> imu_v12_0.c file
> 
> The ucode_prefix size was reduced from 30 to 15 to ensure the snprintf
> function does not exceed the size of the fw_name buffer.
> 
> Thus fixing the below with gcc W=1:
> drivers/gpu/drm/amd/amdgpu/imu_v12_0.c: In function ‘imu_v12_0_init_microcode’:
> drivers/gpu/drm/amd/amdgpu/imu_v12_0.c:51:54: warning: ‘_imu.bin’ directive output may be truncated writing 8 bytes into a region of size between 4 and 33 [-Wformat-truncation=]
>    51 |         snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_imu.bin", ucode_prefix);
>       |                                                      ^~~~~~~~
> drivers/gpu/drm/amd/amdgpu/imu_v12_0.c:51:9: note: ‘snprintf’ output between 16 and 45 bytes into a destination of size 40
>    51 |         snprintf(fw_name, sizeof(fw_name), "amdgpu/%s_imu.bin", ucode_prefix);
>       |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Cc: Lijo Lazar <lijo.lazar at amd.com>
> Cc: Christian König <christian.koenig at amd.com>
> Cc: Alex Deucher <alexander.deucher at amd.com>
> Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam at amd.com>

Reviewed-by: Lijo Lazar <lijo.lazar at amd.com>

Thanks,
Lijo
> ---
>  drivers/gpu/drm/amd/amdgpu/imu_v12_0.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/imu_v12_0.c b/drivers/gpu/drm/amd/amdgpu/imu_v12_0.c
> index ec2a4613567a..032ae12b2be2 100644
> --- a/drivers/gpu/drm/amd/amdgpu/imu_v12_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/imu_v12_0.c
> @@ -39,7 +39,7 @@ MODULE_FIRMWARE("amdgpu/gc_12_0_1_imu.bin");
>  static int imu_v12_0_init_microcode(struct amdgpu_device *adev)
>  {
>  	char fw_name[40];
> -	char ucode_prefix[30];
> +	char ucode_prefix[15];
>  	int err;
>  	const struct imu_firmware_header_v1_0 *imu_hdr;
>  	struct amdgpu_firmware_info *info = NULL;