From mboxrd@z Thu Jan  1 00:00:00 1970
From: Parav Pandit <parav@mellanox.com>
Date: Tue, 16 Apr 2019 22:54:42 +0000
Subject: RE: [PATCH] IB/mlx5: add checking for "vf" from do_setvfinfo()
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References: <20190412175504.GA20857@kadam>
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> -----Original Message-----
> From: Dan Carpenter <dan.carpenter@oracle.com>
> Sent: Tuesday, April 16, 2019 3:21 AM
> To: Parav Pandit <parav@mellanox.com>
> 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()
> 
> On Mon, Apr 15, 2019 at 08:04:43PM +0000, Parav Pandit wrote:
> >
> >
> > > -----Original Message-----
> > > From: Dan Carpenter <dan.carpenter@oracle.com>
> > > Sent: Monday, April 15, 2019 4:46 AM
> > > To: Parav Pandit <parav@mellanox.com>
> > > 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()
> > >
> > > On Fri, Apr 12, 2019 at 08:25:05PM +0000, Parav Pandit wrote:
> > > >
> > > >
> > > > > -----Original Message-----
> > > > > From: linux-rdma-owner@vger.kernel.org <linux-rdma-
> > > > > owner@vger.kernel.org> On Behalf Of Dan Carpenter
> > > > > Sent: Friday, April 12, 2019 12:55 PM
> > > > > To: Leon Romanovsky <leon@kernel.org>; Eli Cohen
> > > > > <eli@mellanox.com>
> > > > > Cc: Doug Ledford <dledford@redhat.com>; Jason Gunthorpe
> > > > > <jgg@ziepe.ca>; linux-rdma@vger.kernel.org;
> > > > > kernel-janitors@vger.kernel.org
> > > > > Subject: [PATCH] IB/mlx5: add checking for "vf" from
> > > > > do_setvfinfo()
> > > > >
> > > > > My static checker complains that these "vf" variables come from
> > > > > the user in
> > > > > do_setvfinfo() and haven't been checked to make sure they're valid.
> > > > >
> > > > > Fixes: eff901d30e6c ("IB/mlx5: Implement callbacks for
> > > > > manipulating
> > > > > VFs")
> > > > > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > > > > ---
> > > > > Untested static checker stuff.  Please review carefully.
> > > > >
> > > > >  drivers/infiniband/hw/mlx5/ib_virt.c | 6 ++++++
> > > > >  1 file changed, 6 insertions(+)
> > > > >
> > > > > diff --git a/drivers/infiniband/hw/mlx5/ib_virt.c
> > > > > b/drivers/infiniband/hw/mlx5/ib_virt.c
> > > > > index 649a3364f838..9a8eebe3d462 100644
> > > > > --- a/drivers/infiniband/hw/mlx5/ib_virt.c
> > > > > +++ b/drivers/infiniband/hw/mlx5/ib_virt.c
> > > > > @@ -56,6 +56,9 @@ int mlx5_ib_get_vf_config(struct ib_device
> > > > > *device, int vf, u8 port,
> > > > >  	struct mlx5_hca_vport_context *rep;
> > > > >  	int err;
> > > > >
> > > > > +	if (vf < 0 || vf >= pci_sriov_get_totalvfs(mdev->pdev))
> > > > > +		return -EINVAL;
> > > > > +
> > > > I traced back ndo_get_vf_config and friend functions. vf number is
> > > > u32
> > > from user space.
> > > >
> > > > And all the VF operations at ndo ops level and at driver level
> > > > should be
> > > changed from int to u32.
> > > > After that vf < 0 check is not needed.
> > > >
> > >
> > > I've been thinking about this and I don't think it's a good idea.
> > > It just makes backporting the fix a lot more complicated.  It might
> > > be a good idea as a cleanup later though.
> > >
> > Data type correction I think is common approach. I have seen int to bool
> changes.
> >
> > Regarding this fix, I am saying if vf index is negative (as very large positive
> number for fw), it will get failed anyway when its > total_num_vfs.
> 
> Yeah.  But the call tree here is:
> 
> do_setvfinfo()
> -> ops->ndo_get_vf_config()
>    -> rtnl_fill_vfinfo()
>       -> dev->netdev_ops->ndo_get_vf_config(dev, vfs_num, &ivi)
>          -> ipoib_get_vf_config()
>             -> ib_get_vf_config
>                -> device->ops.get_vf_config(device, vf, port, info);
> 
> Changing the ->ndo_get_vf_config() pointer means you have to update 20
> functions in various drivers.  It becomes quite involved.  We should apply
> this simple self contained fix then worry about doing other cleanups later.
> 
But if a static checker is run on following functions, they need for vf < 0 check.

i40e_ndo_get_vf_config
mlx5e_get_vf_config
bnxt_get_vf_config
etc and few more.

So few functions to be updated anyway.
So why not better do the right cleanup.

Also there is nothing prevents for vf to go to zero after pci_sriov_get_totalvfs() is passed.

> > Do you see any error by passing large number currently which desires this
> patch or just the static checker?
> > If it is static checker, I would prefer we fix the datatype..
> 
> I don't really understand the question, but I haven't tested this fix, it's from
> static analysis.
> 
Ok. yeah, that is what I was asking.

> regards,
> dan carpenter