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

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

include/net/sock.h

+8 −7
Original line number Diff line number Diff line
@@ -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;