From 04d55b257cbb9eb6c722410251d3b7df00835c6c Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Mon, 7 May 2018 11:08:52 -0700 Subject: [PATCH] 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 Signed-off-by: Alexander Duyck Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/udp_offload.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) 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); -- 2.7.4