diff options
| author | Eric Dumazet <edumazet@google.com> | 2017-03-03 21:01:03 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-04-18 07:55:54 +0200 |
| commit | 61cc261bd334b3e360def9b91558fdd5937fd525 (patch) | |
| tree | 9b14939ad002e690303f0a2244b6328f6d8a2a02 /net | |
| parent | 66aebd46a4d73f8685f275a23d58fff4985df448 (diff) | |
net: fix socket refcounting in skb_complete_tx_timestamp()
commit 9ac25fc063751379cb77434fef9f3b088cd3e2f7 upstream.
TX skbs do not necessarily hold a reference on skb->sk->sk_refcnt
By the time TX completion happens, sk_refcnt might be already 0.
sock_hold()/sock_put() would then corrupt critical state, like
sk_wmem_alloc and lead to leaks or use after free.
Fixes: 62bccb8cdb69 ("net-timestamp: Make the clone operation stand-alone from phy timestamping")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/skbuff.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index fdeddebe499d..b2e2a53c2284 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3617,13 +3617,14 @@ void skb_complete_tx_timestamp(struct sk_buff *skb, { struct sock *sk = skb->sk; - /* take a reference to prevent skb_orphan() from freeing the socket */ - sock_hold(sk); - - *skb_hwtstamps(skb) = *hwtstamps; - __skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND); - - sock_put(sk); + /* Take a reference to prevent skb_orphan() from freeing the socket, + * but only if the socket refcount is not zero. + */ + if (likely(atomic_inc_not_zero(&sk->sk_refcnt))) { + *skb_hwtstamps(skb) = *hwtstamps; + __skb_complete_tx_timestamp(skb, sk, SCM_TSTAMP_SND); + sock_put(sk); + } } EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp); |