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authorEric Dumazet <edumazet@google.com>2012-12-06 13:54:59 +0000
committerDavid S. Miller <davem@davemloft.net>2012-12-07 14:39:29 -0500
commitc3c7c254b2e8cd99b0adf288c2a1bddacd7ba255 (patch)
treecca25bcae0cc6172a616335041c1e54a33db451c
parent93b174ad71b08e504c2cf6e8a58ecce778b77a40 (diff)
net: gro: fix possible panic in skb_gro_receive()
commit 2e71a6f8084e (net: gro: selective flush of packets) added a bug for skbs using frag_list. This part of the GRO stack is rarely used, as it needs skb not using a page fragment for their skb->head. Most drivers do use a page fragment, but some of them use GFP_KERNEL allocations for the initial fill of their RX ring buffer. napi_gro_flush() overwrite skb->prev that was used for these skb to point to the last skb in frag_list. Fix this using a separate field in struct napi_gro_cb to point to the last fragment. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/netdevice.h3
-rw-r--r--net/core/dev.c2
-rw-r--r--net/core/skbuff.c6
3 files changed, 8 insertions, 3 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index f8eda0276f0..a848ffc327f 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1488,6 +1488,9 @@ struct napi_gro_cb {
/* Used in ipv6_gro_receive() */
int proto;
+
+ /* used in skb_gro_receive() slow path */
+ struct sk_buff *last;
};
#define NAPI_GRO_CB(skb) ((struct napi_gro_cb *)(skb)->cb)
diff --git a/net/core/dev.c b/net/core/dev.c
index c0946cb2b35..e5942bf45a6 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3451,6 +3451,8 @@ static int napi_gro_complete(struct sk_buff *skb)
struct list_head *head = &ptype_base[ntohs(type) & PTYPE_HASH_MASK];
int err = -ENOENT;
+ BUILD_BUG_ON(sizeof(struct napi_gro_cb) > sizeof(skb->cb));
+
if (NAPI_GRO_CB(skb)->count == 1) {
skb_shinfo(skb)->gso_size = 0;
goto out;
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 4007c1437fd..3f0636cd76c 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3004,7 +3004,7 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb)
skb_shinfo(nskb)->gso_size = pinfo->gso_size;
pinfo->gso_size = 0;
skb_header_release(p);
- nskb->prev = p;
+ NAPI_GRO_CB(nskb)->last = p;
nskb->data_len += p->len;
nskb->truesize += p->truesize;
@@ -3030,8 +3030,8 @@ merge:
__skb_pull(skb, offset);
- p->prev->next = skb;
- p->prev = skb;
+ NAPI_GRO_CB(p)->last->next = skb;
+ NAPI_GRO_CB(p)->last = skb;
skb_header_release(skb);
done: