| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 026/137] ipv4: only create late gso-skb if skb is already set up with CHECKSUM_PARTIAL | Date | Mon, 18 Apr 2016 11:28:08 +0900 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Hannes Frederic Sowa <hannes@stressinduktion.org>
[ Upstream commit a8c4a2522a0808c5c2143612909717d1115c40cf ]
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.
Commit d749c9cbffd6 ("ipv4: no CHECKSUM_PARTIAL on MSG_MORE corked sockets") started to exposes this bug.
Fixes: d749c9cbffd6 ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/ipv4/ip_output.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -1237,13 +1237,16 @@ ssize_t ip_append_page(struct sock *sk, if (!skb) return -EINVAL; - cork->length += size; if ((size + skb->len > mtu) && (sk->sk_protocol == IPPROTO_UDP) && (rt->dst.dev->features & NETIF_F_UFO)) { + if (skb->ip_summed != CHECKSUM_PARTIAL) + return -EOPNOTSUPP; + skb_shinfo(skb)->gso_size = mtu - fragheaderlen; skb_shinfo(skb)->gso_type = SKB_GSO_UDP; } + cork->length += size; while (size > 0) { if (skb_is_gso(skb)) {
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