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udp: Do not copy destructor if one is not present

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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>
This commit is contained in:
Alexander Duyck 2018-05-07 11:08:52 -07:00 committed by David S. Miller
parent 6053d0f189
commit 04d55b257c
1 changed files with 14 additions and 8 deletions
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22
net/ipv4/udp_offload.c
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@ -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);