[PATCH net] ipvlan: fix use after free of skb

[PATCH net] ipvlan: fix use after free of skb

[Sabrina Dubroca]

ipvlan_handle_frame is a rx_handler, and when it returns a value other
than RX_HANDLER_CONSUMED (here, NET_RX_DROP aka RX_HANDLER_ANOTHER),
__netif_receive_skb_core expects that the skb still exists and will
process it further, but we just freed it.

Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
---
 drivers/net/ipvlan/ipvlan_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c
index 8edd6f2a4da6..db9fa220ddae 100644
--- a/drivers/net/ipvlan/ipvlan_core.c
+++ b/drivers/net/ipvlan/ipvlan_core.c
@@ -676,5 +676,5 @@ rx_handler_result_t ipvlan_handle_frame(struct sk_buff **pskb)
 	WARN_ONCE(true, "ipvlan_handle_frame() called for mode = [%hx]\n",
 			  port->mode);
 	kfree_skb(skb);
-	return NET_RX_DROP;
+	return RX_HANDLER_CONSUMED;
 }
-- 
2.6.2

Re: [PATCH net] ipvlan: fix use after free of skb

[David Miller]

From: Sabrina Dubroca <sd@queasysnail.net>
Date: Mon, 16 Nov 2015 22:44:53 +0100

> ipvlan_handle_frame is a rx_handler, and when it returns a value other
> than RX_HANDLER_CONSUMED (here, NET_RX_DROP aka RX_HANDLER_ANOTHER),
> __netif_receive_skb_core expects that the skb still exists and will
> process it further, but we just freed it.
> 
> Fixes: 2ad7bf363841 ("ipvlan: Initial check-in of the IPVLAN driver.")
> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>

Applied.