Messages in this thread | | | Date | Wed, 16 Apr 2008 23:30:10 +0200 | From | "Jesper Juhl" <> | Subject | Re: [PATCH][netlabel] Don't risk NULL ptr deref in netlbl_unlabel_staticlist_gen() if ifindex not found |
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On 16/04/2008, Paul Moore <paul.moore@hp.com> wrote: > On Wednesday 16 April 2008 5:08:58 pm Jesper Juhl wrote: > > Hi, > > > > dev_get_by_index() may return NULL if nothing is found. In > > net/netlabel/netlabel_unlabeled.c::netlbl_unlabel_staticlist_gen() > > the function is called, but the return value is never checked. If it > > returns NULL then we'll deref a NULL pointer on the very next line. > > I checked the callers, and I don't think this can actually happen > > today, but code changes over time and in the future it might happen > > and it does no harm to be defensive and check for the failure, so > > that if/when it happens we'll fail gracefully instead of crashing. > > > > Please consider the patch below for inclusion. > > > > > > Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com> > > > I agree we should check for NULL here. I checked the return of > dev_get_by_index() in the rest of the file I must have just forgotten > to check it here. > > Thanks for finding this and fixing it. > You're welcome.
> Acked-by: Paul Moore <paul.moore@hp.com> >
David, will you merge this in the net tree ?
> > > > > netlabel_unlabeled.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/net/netlabel/netlabel_unlabeled.c > > b/net/netlabel/netlabel_unlabeled.c index 4478f2f..6af9457 100644 > > --- a/net/netlabel/netlabel_unlabeled.c > > +++ b/net/netlabel/netlabel_unlabeled.c > > @@ -1339,6 +1339,10 @@ static int netlbl_unlabel_staticlist_gen(u32 > > cmd, > > > > if (iface->ifindex > 0) { > > dev = dev_get_by_index(&init_net, iface->ifindex); > > + if (!dev) { > > + ret_val = -ENODEV; > > + goto list_cb_failure; > > + } > > ret_val = nla_put_string(cb_arg->skb, > > NLBL_UNLABEL_A_IFACE, dev->name); > > dev_put(dev); >
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