From e66b2f31a068dd67172008459678821a79e4ea24 Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Thu, 9 Jan 2020 07:59:23 -0800 Subject: tcp: clean ext on tx recycle Otherwise we will find stray/unexpected/old extensions value on next iteration. On tcp_write_xmit() we can end-up splitting an already queued skb in two parts, via tso_fragment(). The newly created skb can be allocated via the tx cache and an upper layer will not be aware of it, so that upper layer cannot set the ext properly. Resetting the ext on recycle ensures that stale data is not propagated in to packet headers or elsewhere. An alternative would be add an additional hook in tso_fragment() or in sk_stream_alloc_skb() to init the ext for upper layers that need it. Co-developed-by: Florian Westphal Signed-off-by: Florian Westphal Signed-off-by: Paolo Abeni Reviewed-by: Eric Dumazet Signed-off-by: Mat Martineau Signed-off-by: David S. Miller --- include/net/sock.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/net') diff --git a/include/net/sock.h b/include/net/sock.h index 8766f9bc3e70..432ff73d20f3 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1464,6 +1464,7 @@ static inline void sk_wmem_free_skb(struct sock *sk, struct sk_buff *skb) sk_mem_uncharge(sk, skb->truesize); if (static_branch_unlikely(&tcp_tx_skb_cache_key) && !sk->sk_tx_skb_cache && !skb_cloned(skb)) { + skb_ext_reset(skb); skb_zcopy_clear(skb, true); sk->sk_tx_skb_cache = skb; return; -- cgit v1.2.3-59-g8ed1b