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gro: Fix potential use after free

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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>
This commit is contained in:
Herbert Xu 2008-12-26 14:57:42 -08:00 committed by David S. Miller
parent 843813453f
commit 0da2afd596
1 changed files with 4 additions and 1 deletions
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5
net/core/dev.c
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@ -2390,6 +2390,7 @@ int napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
__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 @@ int napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
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 @@ int napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
count--;
}
if (NAPI_GRO_CB(skb)->same_flow)
if (same_flow)
goto ok;
if (NAPI_GRO_CB(skb)->flush || count >= MAX_GRO_SKBS) {