net: avoid infinite loop in mpls_gso_segment when mpls_hlen == 0
authorBalazs Nemeth <bnemeth@redhat.com>
Tue, 9 Mar 2021 11:31:01 +0000 (12:31 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 17 Mar 2021 16:06:11 +0000 (17:06 +0100)
commit453fff24f52eeb62ab65582848498097273df269
tree065e9c3cb42b0ed858e0268602d15ad69ab62c71
parentfaa3baa2828c5e1c4374f3e60041f75c64f5fcb6
net: avoid infinite loop in mpls_gso_segment when mpls_hlen == 0

commit d348ede32e99d3a04863e9f9b28d224456118c27 upstream.

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. In addition, ensure that the header length is a multiple of four,
which should hold irrespective of the number of stacked labels.

Signed-off-by: Balazs Nemeth <bnemeth@redhat.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/mpls/mpls_gso.c