4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
[ 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@xxxxxxxxxx>
Cc: Jiri Benc <jbenc@xxxxxxxxxx>
Reported-by: Wakko Warner <wakko@xxxxxxxxxxxx>
Cc: Wakko Warner <wakko@xxxxxxxxxxxx>
Signed-off-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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)) {
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html