On Mon, Mar 8, 2021 at 5:32 AM Balazs Nemeth <bnemeth@xxxxxxxxxx> wrote: > > A packet with skb_inner_network_header(skb) == skb_network_header(skb) > and ETH_P_MPLS_UC will prevent mpls_gso_segment from pulling any headers > from the packet. Subsequently, the call to skb_mac_gso_segment will > again call mpls_gso_segment with the same packet leading to an infinite > loop. > > Signed-off-by: Balazs Nemeth <bnemeth@xxxxxxxxxx> > --- > net/mpls/mpls_gso.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/mpls/mpls_gso.c b/net/mpls/mpls_gso.c > index b1690149b6fa..cc1b6457fc93 100644 > --- a/net/mpls/mpls_gso.c > +++ b/net/mpls/mpls_gso.c > @@ -27,7 +27,7 @@ static struct sk_buff *mpls_gso_segment(struct sk_buff *skb, > > skb_reset_network_header(skb); > mpls_hlen = skb_inner_network_header(skb) - skb_network_header(skb); > - if (unlikely(!pskb_may_pull(skb, mpls_hlen))) > + if (unlikely(!mpls_hlen || !pskb_may_pull(skb, mpls_hlen))) > goto out; Good cathc. Besides length zero, this can be more strict: a label is 4B, so mpls_hlen needs to be >= 4B. Perhaps even aligned to 4B, too, but not if there may be other encap on top. Unfortunately there is no struct or type definition that we can use a sizeof instead of open coding the raw constant. _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
