Virtualization - Feb 2021 - [PATCH] vdpa/mlx5: fix param validation in mlx5_vdpa_get_config()

On Tue, Feb 09, 2021 at 07:43:02AM +0200, Eli Cohen
wrote:
>On Mon, Feb 08, 2021 at 05:17:41PM +0100, Stefano Garzarella wrote:
>> It's legal to have 'offset + len' equal to
>> sizeof(struct virtio_net_config), since 'ndev->config' is a
>> 'struct virtio_net_config', so we can safely copy its content
under
>> this condition.
>>
>> Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported
mlx5 devices")
>> Cc: stable at vger.kernel.org
>> Signed-off-by: Stefano Garzarella <sgarzare at redhat.com>
>
>Acked-by: Eli Cohen <elic at nvidia.com>
>
>BTW, same error in vdpa_sim you may want to fix.
>
Commit 65b709586e22 ("vdpa_sim: add get_config callback in 
vdpasim_dev_attr") unintentionally solved it.

Since it's a simulator, maybe we can avoid solving it in the stable 
branches. Or does it matter?

Thanks,
Stefano
>> ---
>>  drivers/vdpa/mlx5/net/mlx5_vnet.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> index dc88559a8d49..10e9b09932eb 100644
>> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> @@ -1820,7 +1820,7 @@ static void mlx5_vdpa_get_config(struct
vdpa_device *vdev, unsigned int offset,
>>  	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
>>  	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
>>
>> -	if (offset + len < sizeof(struct virtio_net_config))
>> +	if (offset + len <= sizeof(struct virtio_net_config))
>>  		memcpy(buf, (u8 *)&ndev->config + offset, len);
>>  }
>>
>> --
>> 2.29.2
>>
>

On 2021/2/9 ??5:00, Stefano Garzarella wrote:
> On Tue, Feb 09, 2021 at 07:43:02AM +0200, Eli Cohen wrote:
>> On Mon, Feb 08, 2021 at 05:17:41PM +0100, Stefano Garzarella wrote:
>>> It's legal to have 'offset + len' equal to
>>> sizeof(struct virtio_net_config), since 'ndev->config'
is a
>>> 'struct virtio_net_config', so we can safely copy its
content under
>>> this condition.
>>>
>>> Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported
mlx5
>>> devices")
>>> Cc: stable at vger.kernel.org
>>> Signed-off-by: Stefano Garzarella <sgarzare at redhat.com>
>>
>> Acked-by: Eli Cohen <elic at nvidia.com>
>>
>> BTW, same error in vdpa_sim you may want to fix.
>>
>
> Commit 65b709586e22 ("vdpa_sim: add get_config callback in 
> vdpasim_dev_attr") unintentionally solved it.
>
> Since it's a simulator, maybe we can avoid solving it in the stable 
> branches. Or does it matter?

I think not, since the module depends on RUNTIME_TESTING_MENU.

Thanks



>
> Thanks,
> Stefano