diff options
| author | Eric Dumazet <edumazet@google.com> | 2017-03-03 21:01:02 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-03-07 14:06:14 -0800 |
| commit | dd4f10722aeb10f4f582948839f066bebe44e5fb (patch) | |
| tree | 208405a490829ceb4a413eb4f388a7185f675e35 | |
| parent | 146d8fef9da1ba854de7fa28b9cb9eb147535f88 (diff) | |
net: fix socket refcounting in skb_complete_wifi_ack()
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.
Fixes: bf7fa551e0ce ("mac80211: Resolve sk_refcnt/sk_wmem_alloc issue in wifi ack path")
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>
| -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 f3557958e9bf..e2f37a560ec4 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3893,7 +3893,7 @@ void skb_complete_wifi_ack(struct sk_buff *skb, bool acked) { struct sock *sk = skb->sk; struct sock_exterr_skb *serr; - int err; + int err = 1; skb->wifi_acked_valid = 1; skb->wifi_acked = acked; @@ -3903,14 +3903,15 @@ void skb_complete_wifi_ack(struct sk_buff *skb, bool acked) serr->ee.ee_errno = ENOMSG; serr->ee.ee_origin = SO_EE_ORIGIN_TXSTATUS; - /* take a reference to prevent skb_orphan() from freeing the socket */ - sock_hold(sk); - - err = sock_queue_err_skb(sk, skb); + /* 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))) { + err = sock_queue_err_skb(sk, skb); + sock_put(sk); + } if (err) kfree_skb(skb); - - sock_put(sk); } EXPORT_SYMBOL_GPL(skb_complete_wifi_ack); |