| Message ID | 20081226224401.GA22329@gondor.apana.org.au |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Herbert Xu <herbert@gondor.apana.org.au> Date: Sat, 27 Dec 2008 09:44:01 +1100 > 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> Applied, thanks Herbert. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/core/dev.c b/net/core/dev.c index daca72e..9d60941 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -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) {
Hi Dave: While implementing GRO support for page frags, I found a little bug in the original code. 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> Thanks,