udp: Do not copy destructor if one is not present
This patch makes it so that if a destructor is not present we avoid trying
to update the skb socket or any reference counting that would be associated
with the NULL socket and/or descriptor. By doing this we can support
traffic coming from another namespace without any issues.
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index d4f2dac..ede2a73 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -195,6 +195,7 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
struct sk_buff *segs, *seg;
struct udphdr *uh;
unsigned int mss;
+ bool copy_dtor;
__sum16 check;
__be16 newlen;
@@ -205,12 +206,14 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
skb_pull(gso_skb, sizeof(*uh));
/* clear destructor to avoid skb_segment assigning it to tail */
- WARN_ON_ONCE(gso_skb->destructor != sock_wfree);
- gso_skb->destructor = NULL;
+ copy_dtor = gso_skb->destructor == sock_wfree;
+ if (copy_dtor)
+ gso_skb->destructor = NULL;
segs = skb_segment(gso_skb, features);
if (unlikely(IS_ERR_OR_NULL(segs))) {
- gso_skb->destructor = sock_wfree;
+ if (copy_dtor)
+ gso_skb->destructor = sock_wfree;
return segs;
}
@@ -229,9 +232,11 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
check = csum16_add(csum16_sub(uh->check, uh->len), newlen);
for (;;) {
- seg->destructor = sock_wfree;
- seg->sk = sk;
- sum_truesize += seg->truesize;
+ if (copy_dtor) {
+ seg->destructor = sock_wfree;
+ seg->sk = sk;
+ sum_truesize += seg->truesize;
+ }
if (!seg->next)
break;
@@ -263,8 +268,9 @@ struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
uh->check = gso_make_checksum(seg, ~check) ? : CSUM_MANGLED_0;
/* update refcount for the packet */
- refcount_add(sum_truesize - gso_skb->truesize, &sk->sk_wmem_alloc);
-
+ if (copy_dtor)
+ refcount_add(sum_truesize - gso_skb->truesize,
+ &sk->sk_wmem_alloc);
return segs;
}
EXPORT_SYMBOL_GPL(__udp_gso_segment);