packet: fill the gap of TPACKET_ALIGNMENT with zeros

struct tpacket{2,3}_hdr is aligned to a multiple of TPACKET_ALIGNMENT.
Explicitly defining and zeroing the gap of this makes additional changes
easier.

Signed-off-by: Atzm Watanabe <atzm@stratosphere.co.jp>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 4 insertions, 2 deletions

diff --git a/include/uapi/linux/if_packet.h b/include/uapi/linux/if_packet.h
index 1e24aa701cbd..9185dc9a4485 100644
--- a/include/uapi/linux/if_packet.h
+++ b/include/uapi/linux/if_packet.h
@@ -133,7 +133,7 @@ struct tpacket2_hdr {
         __u32           tp_sec;
         __u32           tp_nsec;
         __u16           tp_vlan_tci;
-        __u16           tp_padding;
+        __u8            tp_padding[6];
 };
 
 struct tpacket_hdr_variant1 {
@@ -154,6 +154,7 @@ struct tpacket3_hdr {
         union {
                 struct tpacket_hdr_variant1 hv1;
         };
+        __u8            tp_padding[12];
 };
 
 struct tpacket_bd_ts {
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 4fd52181b6ce..f281999ba92e 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1929,7 +1929,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
                 } else {
                         h.h2->tp_vlan_tci = 0;
                 }
-                h.h2->tp_padding = 0;
+                memset(h.h2->tp_padding, 0, sizeof(h.h2->tp_padding));
                 hdrlen = sizeof(*h.h2);
                 break;
         case TPACKET_V3:
@@ -1943,6 +1943,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev,
                 h.h3->tp_net = netoff;
                 h.h3->tp_sec  = ts.tv_sec;
                 h.h3->tp_nsec = ts.tv_nsec;
+                memset(h.h3->tp_padding, 0, sizeof(h.h3->tp_padding));
                 hdrlen = sizeof(*h.h3);
                 break;
         default: