netdev - Re: [PATCH v3 net] ixgbe: check adapter->vfinfo before dereference

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Date:	Thu, 16 Oct 2014 00:32:30 -0700
From:	Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To:	Thierry Herbelot <thierry.herbelot@...nd.com>
Cc:	"Tantilov, Emil S" <emil.s.tantilov@...el.com>,
	"Brandeburg, Jesse" <jesse.brandeburg@...el.com>,
	"Allan, Bruce W" <bruce.w.allan@...el.com>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: [PATCH v3 net] ixgbe: check adapter->vfinfo before dereference

On Thu, 2014-10-16 at 09:23 +0200, Thierry Herbelot wrote:
> On 10/16/2014 12:50 AM, Tantilov, Emil S wrote:
> >> -----Original Message-----
> >> From: Thierry Herbelot [mailto:thierry.herbelot@...nd.com]
> >> Sent: Wednesday, October 15, 2014 2:58 AM
> >> To: Kirsher, Jeffrey T; Brandeburg, Jesse; Allan, Bruce W;
> >> netdev@...r.kernel.org; Tantilov, Emil S
> >> Cc: Thierry Herbelot
> >> Subject: [PATCH v3 net] ixgbe: check adapter->vfinfo before dereference
> >>
> >> this protects against the following panic:
> >> (before a VF was actually created on p96p1 PF Ethernet port)
> >>
> >> ip link set p96p1 vf 0 spoofchk off
> >> BUG: unable to handle kernel NULL pointer dereference at 0000000000000052
> >> IP: [<ffffffffa044a1c1>]
> >> ixgbe_ndo_set_vf_spoofchk+0x51/0x150 [ixgbe]
> >>
> >> Signed-off-by: Thierry Herbelot <thierry.herbelot@...nd.com>
> >> ---
> >>
> >> v2:
> >>   compilation fixes
> >>
> >> v3:
> >>   remove checks in functions where vfinfo is known not to be NULL
> >>   return -EINVAL as error code
> >>
> >> drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c |   42
> >> ++++++++++++++++++++++--
> >> 1 file changed, 40 insertions(+), 2 deletions(-)
> >
> > Actually looking into this a bit more, the check for vfinfo is not sufficient
> > because it does not protect against specifying vf that is outside of sriov_num_vfs range.
> >
> > All of the ndo functions have a check for it except for ixgbevf_ndo_set_spoofcheck().
> >
> > The following patch should be all we need to protect against this panic:
> >
> > This patch adds a check to return -EINVAL when setting spoofcheck on
> > VF that is not configured.
> >
> > Reported-by: Thierry Herbelot <thierry.herbelot@...nd.com>
> > Signed-off-by: Emil Tantilov <emil.s.tantilov@...el.com>
> > ---
> >   drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c |    3 +++
> >   1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
> > index 706fc69..97c85b8 100644
> > --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
> > +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_sriov.c
> > @@ -1261,6 +1261,9 @@ int ixgbe_ndo_set_vf_spoofchk(struct net_device *netdev, int vf, bool setting)
> >   	struct ixgbe_hw *hw = &adapter->hw;
> >   	u32 regval;
> >
> > +	if (vf >= adapter->num_vfs)
> > +		return -EINVAL;
> > +
> >   	adapter->vfinfo[vf].spoofchk_enabled = setting;
> >
> >   	regval = IXGBE_READ_REG(hw, IXGBE_PFVFSPOOF(vf_target_reg));
> >
> >
> 
> Hello,
> 
> Indeed your patch solves the initial issue.
> 
> And indeed I also double-checked that all other instances are protected 
> by the (vf >= adapter->num_vfs) condition.

So Thierry, can I add your Acked-by or Tested-by to Emil's patch?

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