gro: Fix potential use after free
The initial skb may have been freed after napi_gro_complete in
napi_gro_receive if it was merged into an existing packet. Thus
we cannot check same_flow (which indicates whether it was merged)
after calling napi_gro_complete.
This patch fixes this by saving the same_flow status before the
call to napi_gro_complete.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index 536a8ac..303e984 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2390,6 +2390,7 @@
__be16 type = skb->protocol;
struct list_head *head = &ptype_base[ntohs(type) & PTYPE_HASH_MASK];
int count = 0;
+ int same_flow;
int mac_len;
if (!(skb->dev->features & NETIF_F_GRO))
@@ -2425,6 +2426,8 @@
if (&ptype->list == head)
goto normal;
+ same_flow = NAPI_GRO_CB(skb)->same_flow;
+
if (pp) {
struct sk_buff *nskb = *pp;
@@ -2434,7 +2437,7 @@
count--;
}
- if (NAPI_GRO_CB(skb)->same_flow)
+ if (same_flow)
goto ok;
if (NAPI_GRO_CB(skb)->flush || count >= MAX_GRO_SKBS) {