Re: [PATCH rdma-rc] RDMA/core: Fix pkey and port assignment in get_new_pps

[Leon Romanovsky <leon@kernel.org>]

On Thu, Feb 27, 2020 at 02:07:10PM +0000, Marciniszyn, Mike wrote:
> >
> > From: Maor Gottlieb <maorg@mellanox.com>
> >
> > When port is part of the modify mask, then we should take
> > it from the qp_attr and not from the old pps. Same for PKEY.
> >
> > Cc: <stable@vger.kernel.org>
> > Fixes: 1dd017882e01 ("RDMA/core: Fix protection fault in
> > get_pkey_idx_qp_list")
> > Signed-off-by: Maor Gottlieb <maorg@mellanox.com>
> > Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
> > ---
> >  drivers/infiniband/core/security.c | 12 ++++++++----
> >  1 file changed, 8 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/infiniband/core/security.c
> > b/drivers/infiniband/core/security.c
> > index b9a36ea244d4..2d5608315dc8 100644
> > --- a/drivers/infiniband/core/security.c
> > +++ b/drivers/infiniband/core/security.c
> > @@ -340,11 +340,15 @@ static struct ib_ports_pkeys *get_new_pps(const
> > struct ib_qp *qp,
> >  		return NULL;
> >
> >  	if (qp_attr_mask & IB_QP_PORT)
> > -		new_pps->main.port_num =
> > -			(qp_pps) ? qp_pps->main.port_num : qp_attr-
> > >port_num;
> > +		new_pps->main.port_num = qp_attr->port_num;
> > +	else if (qp_pps)
> > +		new_pps->main.port_num = qp_pps->main.port_num;
> > +
> >  	if (qp_attr_mask & IB_QP_PKEY_INDEX)
> > -		new_pps->main.pkey_index = (qp_pps) ? qp_pps-
> > >main.pkey_index :
> > -						      qp_attr->pkey_index;
> > +		new_pps->main.pkey_index = qp_attr->pkey_index;
> > +	else if (qp_pps)
> > +		new_pps->main.pkey_index = qp_pps->main.pkey_index;
> > +
> >  	if ((qp_attr_mask & IB_QP_PKEY_INDEX) && (qp_attr_mask &
> > IB_QP_PORT))
> >  		new_pps->main.state = IB_PORT_PKEY_VALID;
> >
>
> I agree with this aspect of the patch and it does fix the panic, because the correct unit
> is gotten from qp_pps.
>
> My issue is that the new_pps->main.state will come back as 0, and the insert routine will drop any new pkey index update.
>
> The sequence I'm concerned about is:
>
> 0x71 attr mask with both pkey index and port.
>
> A ulp decides to change the pkey index and does an 0x51 modify without setting the unit.
>
> I see new_pps->main.state being returned as 0 and port_pkey_list_insert() will early out.

I see, maybe we can store the main.state in qps and restore it from there?

>
> I asked this exact question in https://marc.info/?l=linux-rdma&m=158278763015030&w=2.
>
> I also asked about the logical or, and you answered that pointing to an additional patch.
>
> You but didn't address the main.state being 0 and losing the pkey_index update in the 0x51 modify.
>
> Mike
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