Re: [PATCH 5.10 1/1] i40e: Add checking for null for nlmsg_find_attr()

[Jesse Brandeburg]

On 1/26/2023 11:55 AM, Jesse Brandeburg wrote:
> On 1/26/2023 5:55 AM, Natalia Petrova wrote:
> > The result of nlmsg_find_attr() 'br_spec' is dereferenced in
> > nla_for_each_nested(), but it can take null value in nla_find() function,
> > which will result in an error.
> >
> > Found by Linux Verification Center (linuxtesting.org) with SVACE.
> >
> > Fixes: 51616018dd1b ("i40e: Add support for getlink, setlink ndo ops")
> > Signed-off-by: Natalia Petrova <n.petrova@xxxxxxxxxx>
> > ---
> >   drivers/net/ethernet/intel/i40e/i40e_main.c | 2 ++
> >   1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c 
> > b/drivers/net/ethernet/intel/i40e/i40e_main.c
> > index 53d0083e35da..4626d2a1af91 100644
> > --- a/drivers/net/ethernet/intel/i40e/i40e_main.c
> > +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
> > @@ -13167,6 +13167,8 @@ static int i40e_ndo_bridge_setlink(struct 
> > net_device *dev,
> >       }
> >       br_spec = nlmsg_find_attr(nlh, sizeof(struct ifinfomsg), 
> > IFLA_AF_SPEC);
> > +    if (!br_spec)
> > +        return -EINVAL;
> >       nla_for_each_nested(attr, br_spec, rem) {
> >           __u16 mode;
>
> Makes sense to me. Thanks.
>
> Reviewed-by: Jesse Brandeburg <jesse.brandeburg@xxxxxxxxx>

I presume that you meant this to be targeted to the "net" tree, which 
you should indicate with the subject line:
[PATCH net ...]

as per the netdev rules published [1], and generally you don't need a 
cover letter for a single patch.

[1] https://www.kernel.org/doc/html/v5.10/networking/netdev-FAQ.html