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authorHerbert Xu <herbert@gondor.apana.org.au>2008-12-26 14:57:42 -0800
committerDavid S. Miller <davem@davemloft.net>2008-12-26 14:57:42 -0800
commit0da2afd59653d2edf5c8e0f09b23f367ab5bc80f (patch)
treed6dad9cf3ca8a352409b5ce5e8e2445434aa00f5
parent843813453f52e3378fc988c8364063fd4cb9d0e3 (diff)
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>
-rw-r--r--net/core/dev.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 536a8ac189c8..303e984ee6a6 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) {