[engineering.redhat.com #498403] Re: [PATCH v2] nbd_genl_status: null check for nla_nest_start

[Red Hat Product Security <secalert@redhat.com>]

Hi Navid,

Not sure if you meant to cc secalert@redhat.com on this. If anything is needed
from our side please let us know!

On Wed Oct 16 22:17:42 2019, navid.emamdoost@gmail.com wrote:
> Hi Michal, please check v3 at
> https://lore.kernel.org/patchwork/patch/1126650/
>
>
> Thanks,
> Navid.
>
> On Tue, Sep 10, 2019 at 6:35 AM Michal Kubecek <mkubecek@suse.cz>
> wrote:
> >
> > (Just stumbled upon this patch when link to it came with a CVE bug
> report.)
> >
> > On Mon, Jul 29, 2019 at 11:42:26AM -0500, Navid Emamdoost wrote:
> > > nla_nest_start may fail and return NULL. The check is inserted,
> and
> > > errno is selected based on other call sites within the same source
> code.
> > > Update: removed extra new line.
> > >
> > > Signed-off-by: Navid Emamdoost <navid.emamdoost@gmail.com>
> > > Reviewed-by: Bob Liu <bob.liu@oracle.com>
> > > ---
> > > drivers/block/nbd.c | 5 +++++
> > > 1 file changed, 5 insertions(+)
> > >
> > > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
> > > index 9bcde2325893..2410812d1e82 100644
> > > --- a/drivers/block/nbd.c
> > > +++ b/drivers/block/nbd.c
> > > @@ -2149,6 +2149,11 @@ static int nbd_genl_status(struct sk_buff
> *skb, struct genl_info *info)
> > > }
> > >
> > > dev_list = nla_nest_start_noflag(reply,
> NBD_ATTR_DEVICE_LIST);
> > > + if (!dev_list) {
> > > + ret = -EMSGSIZE;
> > > + goto out;
> > > + }
> > > +
> > > if (index == -1) {
> > > ret = idr_for_each(&nbd_index_idr, &status_cb,
> reply);
> > > if (ret) {
> >
> > You should also call nlmsg_free(reply) when you bail out so that you
> > don't introduce a memory leak.
> >
> > Michal Kubecek
>
>
>


--
Kat Bost
Red Hat Product Security