From: Guillaume Nault gnault@redhat.com
commit 4296adc3e32f5d544a95061160fe7e127be1b9ff upstream.
Openvswitch allows to drop a packet's Ethernet header, therefore skb_mpls_push() and skb_mpls_pop() might be called with ethernet=true and mac_len=0. In that case the pointer passed to skb_mod_eth_type() doesn't point to an Ethernet header and the new Ethertype is written at unexpected locations.
Fix this by verifying that mac_len is big enough to contain an Ethernet header.
Fixes: fa4e0f8855fc ("net/sched: fix corrupted L2 header with MPLS 'push' and 'pop' actions") Signed-off-by: Guillaume Nault gnault@redhat.com Acked-by: Davide Caratti dcaratti@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/core/skbuff.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -5621,7 +5621,7 @@ int skb_mpls_push(struct sk_buff *skb, _ lse->label_stack_entry = mpls_lse; skb_postpush_rcsum(skb, lse, MPLS_HLEN);
- if (ethernet) + if (ethernet && mac_len >= ETH_HLEN) skb_mod_eth_type(skb, eth_hdr(skb), mpls_proto); skb->protocol = mpls_proto;
@@ -5661,7 +5661,7 @@ int skb_mpls_pop(struct sk_buff *skb, __ skb_reset_mac_header(skb); skb_set_network_header(skb, mac_len);
- if (ethernet) { + if (ethernet && mac_len >= ETH_HLEN) { struct ethhdr *hdr;
/* use mpls_hdr() to get ethertype to account for VLANs. */