Commit d348ede3 authored by Balazs Nemeth's avatar Balazs Nemeth Committed by David S. Miller
Browse files

net: avoid infinite loop in mpls_gso_segment when mpls_hlen == 0 



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: default avatarBalazs Nemeth <bnemeth@redhat.com>
Acked-by: default avatarWillem de Bruijn <willemb@google.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 924a9bc3

net/mpls/mpls_gso.c

+3 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <linux/netdev_features.h>

#include <linux/netdevice.h>

#include <linux/skbuff.h>

#include <net/mpls.h>



static struct sk_buff *mpls_gso_segment(struct sk_buff *skb,

				       netdev_features_t features)
@@ -27,6 +28,8 @@ 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(!mpls_hlen || mpls_hlen % MPLS_HLEN))

		goto out;

	if (unlikely(!pskb_may_pull(skb, mpls_hlen)))

		goto out;