Re: [PATCH net] ipv4: only create late gso-skb if skb is already set up with CHECKSUM_PARTIAL
From: Wakko Warner <hidden>
Date: 2016-02-26 00:07:09
Hannes Frederic Sowa wrote:
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 <redacted>
Cc: Jiri Benc <redacted>
Reported-by: Wakko Warner <redacted>
Cc: Wakko Warner <redacted>
Signed-off-by: Hannes Frederic Sowa <redacted>I just tested this with 2 of my VMs. It appears to have fixed the issue.
quoted hunk ↗ jump to hunk
--- net/ipv4/ip_output.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 64878efa045c13..565bf64b2b7d60 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c@@ -1236,13 +1236,16 @@ ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page, 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)) {-- 2.5.0
-- Microsoft has beaten Volkswagen's world record. Volkswagen only created 22 million bugs.