From: Jianguo Wu <wujianguo@chinatelecom.cn>
Date: Wed, 8 Dec 2021 10:03:33 +0000 (+0800)
Subject: udp: using datalen to cap max gso segments
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=e6182c63d827ed556bd5a493b63ddc7b2c999ae5;p=linux.git

udp: using datalen to cap max gso segments

commit 158390e45612ef0fde160af0826f1740c36daf21 upstream.

The max number of UDP gso segments is intended to cap to UDP_MAX_SEGMENTS,
this is checked in udp_send_skb():

    if (skb->len > cork->gso_size * UDP_MAX_SEGMENTS) {
        kfree_skb(skb);
        return -EINVAL;
    }

skb->len contains network and transport header len here, we should use
only data len instead.

Fixes: bec1f6f69736 ("udp: generate gso with UDP_SEGMENT")
Signed-off-by: Jianguo Wu <wujianguo@chinatelecom.cn>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/900742e5-81fb-30dc-6e0b-375c6cdd7982@163.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 2ce3fca545d37..3f6823bdd31e5 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -917,7 +917,7 @@ static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4,
 			kfree_skb(skb);
 			return -EINVAL;
 		}
-		if (skb->len > cork->gso_size * UDP_MAX_SEGMENTS) {
+		if (datalen > cork->gso_size * UDP_MAX_SEGMENTS) {
 			kfree_skb(skb);
 			return -EINVAL;
 		}