ipv4: only create late gso-skb if skb is already set up with CHECKSUM_PARTIAL
Otherwise we break the contract with GSO to only pass CHECKSUM_PARTIAL skbs down. This can easily happen with UDP+IPv4 sockets with the first MSG_MORE write smaller than the MTU, second write is a sendfile. Returning -EOPNOTSUPP lets the callers fall back into normal sendmsg path, were we calculate the checksum manually during copying. Commitd749c9cbff
("ipv4: no CHECKSUM_PARTIAL on MSG_MORE corked sockets") started to exposes this bug. Fixes:d749c9cbff
("ipv4: no CHECKSUM_PARTIAL on MSG_MORE corked sockets") Reported-by: Jiri Benc <jbenc@redhat.com> Cc: Jiri Benc <jbenc@redhat.com> Reported-by: Wakko Warner <wakko@animx.eu.org> Cc: Wakko Warner <wakko@animx.eu.org> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -1236,13 +1236,16 @@ ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
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if (!skb)
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if (!skb)
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return -EINVAL;
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return -EINVAL;
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cork->length += size;
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if ((size + skb->len > mtu) &&
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if ((size + skb->len > mtu) &&
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(sk->sk_protocol == IPPROTO_UDP) &&
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(sk->sk_protocol == IPPROTO_UDP) &&
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(rt->dst.dev->features & NETIF_F_UFO)) {
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(rt->dst.dev->features & NETIF_F_UFO)) {
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if (skb->ip_summed != CHECKSUM_PARTIAL)
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return -EOPNOTSUPP;
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skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
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skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
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skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
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skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
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}
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}
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cork->length += size;
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while (size > 0) {
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while (size > 0) {
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if (skb_is_gso(skb)) {
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if (skb_is_gso(skb)) {
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