gso: fix dodgy bit handling for GSO_UDP_L4

Commit 1fd54773c2 ("udp: allow header check for dodgy GSO_UDP_L4
packets.") checks DODGY bit for UDP, but for packets that can be fed
directly to the device after gso_segs reset, it actually falls through
to fragmentation:

https://lore.kernel.org/all/CAJPywTKDdjtwkLVUW6LRA2FU912qcDmQOQGt2WaDo28KzYDg+A@mail.gmail.com/

This change restores the expected behavior of GSO_UDP_L4 packets.

Fixes: 1fd54773c2 ("udp: allow header check for dodgy GSO_UDP_L4 packets.")
Suggested-by: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Signed-off-by: Yan Zhai <yan@cloudflare.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Yan Zhai 2023-07-13 10:28:00 -07:00 committed by David S. Miller
parent a822551c51
commit 9840036786
2 changed files with 12 additions and 7 deletions

View file

@ -274,13 +274,20 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
__sum16 check;
__be16 newlen;
if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)
return __udp_gso_segment_list(gso_skb, features, is_ipv6);
mss = skb_shinfo(gso_skb)->gso_size;
if (gso_skb->len <= sizeof(*uh) + mss)
return ERR_PTR(-EINVAL);
if (skb_gso_ok(gso_skb, features | NETIF_F_GSO_ROBUST)) {
/* Packet is from an untrusted source, reset gso_segs. */
skb_shinfo(gso_skb)->gso_segs = DIV_ROUND_UP(gso_skb->len - sizeof(*uh),
mss);
return NULL;
}
if (skb_shinfo(gso_skb)->gso_type & SKB_GSO_FRAGLIST)
return __udp_gso_segment_list(gso_skb, features, is_ipv6);
skb_pull(gso_skb, sizeof(*uh));
/* clear destructor to avoid skb_segment assigning it to tail */
@ -388,8 +395,7 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
if (!pskb_may_pull(skb, sizeof(struct udphdr)))
goto out;
if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4 &&
!skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST))
if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
return __udp_gso_segment(skb, features, false);
mss = skb_shinfo(skb)->gso_size;

View file

@ -43,8 +43,7 @@ static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb,
if (!pskb_may_pull(skb, sizeof(struct udphdr)))
goto out;
if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4 &&
!skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST))
if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4)
return __udp_gso_segment(skb, features, true);
mss = skb_shinfo(skb)->gso_size;