From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:38822 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751618AbdCROTs (ORCPT ); Sat, 18 Mar 2017 10:19:48 -0400 Subject: Patch "net: fix socket refcounting in skb_complete_tx_timestamp()" has been added to the 4.9-stable tree To: edumazet@google.com, alexander.h.duyck@intel.com, davem@davemloft.net, gregkh@linuxfoundation.org, johannes@sipsolutions.net, soheil@google.com, willemb@google.com Cc: , From: Date: Sat, 18 Mar 2017 22:07:11 +0800 Message-ID: <14898460313866@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled net: fix socket refcounting in skb_complete_tx_timestamp() to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-fix-socket-refcounting-in-skb_complete_tx_timestamp.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Sat Mar 18 22:03:25 CST 2017 From: Eric Dumazet Date: Fri, 3 Mar 2017 21:01:03 -0800 Subject: net: fix socket refcounting in skb_complete_tx_timestamp() From: Eric Dumazet [ Upstream commit 9ac25fc063751379cb77434fef9f3b088cd3e2f7 ] 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 Cc: Alexander Duyck Cc: Johannes Berg Cc: Soheil Hassas Yeganeh Cc: Willem de Bruijn Acked-by: Soheil Hassas Yeganeh Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/skbuff.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3814,13 +3814,14 @@ void skb_complete_tx_timestamp(struct sk if (!skb_may_tx_timestamp(sk, false)) return; - /* 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); Patches currently in stable-queue which might be from edumazet@google.com are queue-4.9/tcp-fix-various-issues-for-sockets-morphing-to-listen-state.patch queue-4.9/tcp-dccp-block-bh-for-syn-processing.patch queue-4.9/dccp-fix-use-after-free-in-dccp_feat_activate_values.patch queue-4.9/net-fix-socket-refcounting-in-skb_complete_tx_timestamp.patch queue-4.9/net-net_enable_timestamp-can-be-called-from-irq-contexts.patch queue-4.9/dccp-unlock-sock-before-calling-sk_free.patch queue-4.9/net-don-t-call-strlen-on-the-user-buffer-in-packet_bind_spkt.patch queue-4.9/net-fix-socket-refcounting-in-skb_complete_wifi_ack.patch queue-4.9/ipv6-orphan-skbs-in-reassembly-unit.patch