RE: [PATCH] IB/mlx5: add checking for "vf" from do_setvfinfo()

[Parav Pandit <parav@mellanox.com>]

> -----Original Message-----
> From: Dan Carpenter <dan.carpenter@oracle.com>
> Sent: Wednesday, April 24, 2019 9:08 AM
> To: Parav Pandit <parav@mellanox.com>; netdev@vger.kernel.org
> Cc: Leon Romanovsky <leon@kernel.org>; Eli Cohen <eli@mellanox.com>;
> Doug Ledford <dledford@redhat.com>; Jason Gunthorpe <jgg@ziepe.ca>;
> linux-rdma@vger.kernel.org; kernel-janitors@vger.kernel.org
> Subject: Re: [PATCH] IB/mlx5: add checking for "vf" from do_setvfinfo()
> 
> I think I'm just going to ask netdev for an opinion on this.  It could be that
> we're just reading the code wrong...
> 
> I'm getting a lot of Smatch warning about buffer underflows.  The problem is
> that Smatch marks everything from nla_data() as unknown and untrusted
> user data.  In do_setvfinfo() we get the "->vf" values from nla_data().  It
> starts as u32, but all the function pointers in net_device_ops use it as a
> signed integer.  Most of the functions return -EINVAL if "vf" is negative but
> there are at least 48 which potentially use negative values as an offset into
> an array.
> 
> To me making "vf" a u32 throughout seems like a good idea but it's an
> extensive patch and I'm not really able to test it at all.  

I will be try to get you patch early next week for core and in mlx5, tested on mlx5 VFs, that possibly you can carry forward?