Commit 912d398d authored by Wei Yongjun's avatar Wei Yongjun Committed by David S. Miller

net: fix skb_add_data_nocache() to calc csum correctly

commit c6e1a0d1 broken the calc
 (net: Allow no-cache copy from user on transmit)
of checksum, which may cause some tcp packets be dropped because
incorrect checksum. ssh does not work under today's net-next-2.6
tree.
Signed-off-by: default avatarWei Yongjun <yjwei@cn.fujitsu.com>
Acked-by: default avatarTom Herbert <therbert@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7b1b3afa
......@@ -1392,14 +1392,14 @@ static inline void sk_nocaps_add(struct sock *sk, int flags)
static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
char __user *from, char *to,
int copy)
int copy, int offset)
{
if (skb->ip_summed == CHECKSUM_NONE) {
int err = 0;
__wsum csum = csum_and_copy_from_user(from, to, copy, 0, &err);
if (err)
return err;
skb->csum = csum_block_add(skb->csum, csum, skb->len);
skb->csum = csum_block_add(skb->csum, csum, offset);
} else if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) {
if (!access_ok(VERIFY_READ, from, copy) ||
__copy_from_user_nocache(to, from, copy))
......@@ -1413,11 +1413,12 @@ static inline int skb_do_copy_data_nocache(struct sock *sk, struct sk_buff *skb,
static inline int skb_add_data_nocache(struct sock *sk, struct sk_buff *skb,
char __user *from, int copy)
{
int err;
int err, offset = skb->len;
err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy), copy);
err = skb_do_copy_data_nocache(sk, skb, from, skb_put(skb, copy),
copy, offset);
if (err)
__skb_trim(skb, skb->len);
__skb_trim(skb, offset);
return err;
}
......@@ -1429,8 +1430,8 @@ static inline int skb_copy_to_page_nocache(struct sock *sk, char __user *from,
{
int err;
err = skb_do_copy_data_nocache(sk, skb, from,
page_address(page) + off, copy);
err = skb_do_copy_data_nocache(sk, skb, from, page_address(page) + off,
copy, skb->len);
if (err)
return err;
......
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