flow dissector: correct size of storage for ARP

The last argument to __skb_header_pointer() should be a buffer large
enough to store struct arphdr. This can be a pointer to a struct arphdr
structure. The code was previously using a pointer to a pointer to
struct arphdr.

By my counting the storage available both before and after is 8 bytes on
x86_64.

Fixes: 55733350e5e8 ("flow disector: ARP support")
Reported-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index c35aae13c8d2..d98d4998213d 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -390,7 +390,7 @@ mpls:
                         unsigned char ar_tip[4];
                 } *arp_eth, _arp_eth;
                 const struct arphdr *arp;
-                struct arphdr *_arp;
+                struct arphdr _arp;
 
                 arp = __skb_header_pointer(skb, nhoff, sizeof(_arp), data,
                                            hlen, &_arp);