[PATCH 3.18 01/24] net-gro: reset skb->pkt_type in napi_reuse_skb()

From: Greg Kroah-Hartman
Date: Mon Nov 26 2018 - 05:52:42 EST

3.18-stable review patch. If anyone has any objections, please let me know.


From: Eric Dumazet <edumazet@xxxxxxxxxx>

[ Upstream commit 33d9a2c72f086cbf1087b2fd2d1a15aa9df14a7f ]

eth_type_trans() assumes initial value for skb->pkt_type

This is indeed the value right after a fresh skb allocation.

However, it is possible that GRO merged a packet with a different
value (like PACKET_OTHERHOST in case macvlan is used), so
we need to make sure napi->skb will have pkt_type set back to

Otherwise, valid packets might be dropped by the stack because
their pkt_type is not PACKET_HOST.

napi_reuse_skb() was added in commit 96e93eab2033 ("gro: Add
internal interfaces for VLAN"), but this bug always has
been there.

Fixes: 96e93eab2033 ("gro: Add internal interfaces for VLAN")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
net/core/dev.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4201,6 +4201,10 @@ static void napi_reuse_skb(struct napi_s
skb->vlan_tci = 0;
skb->dev = napi->dev;
skb->skb_iif = 0;
+ /* eth_type_trans() assumes pkt_type is PACKET_HOST */
+ skb->pkt_type = PACKET_HOST;
skb->encapsulation = 0;
skb_shinfo(skb)->gso_type = 0;
skb->truesize = SKB_TRUESIZE(skb_end_offset(skb));