Patch "phonet: properly unshare skbs in phonet_rcv()" has been added to the 4.4-stable tree

Patch "phonet: properly unshare skbs in phonet_rcv()" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    phonet: properly unshare skbs in phonet_rcv()

to the 4.4-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:
     phonet-properly-unshare-skbs-in-phonet_rcv.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Tue Jan 26 21:31:27 PST 2016
From: Eric Dumazet <edumazet@google.com>
Date: Tue, 12 Jan 2016 08:58:00 -0800
Subject: phonet: properly unshare skbs in phonet_rcv()

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 7aaed57c5c2890634cfadf725173c7c68ea4cb4f ]

Ivaylo Dimitrov reported a regression caused by commit 7866a621043f
("dev: add per net_device packet type chains").

skb->dev becomes NULL and we crash in __netif_receive_skb_core().

Before above commit, different kind of bugs or corruptions could happen
without major crash.

But the root cause is that phonet_rcv() can queue skb without checking
if skb is shared or not.

Many thanks to Ivaylo Dimitrov for his help, diagnosis and tests.

Reported-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Tested-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Remi Denis-Courmont <courmisch@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/phonet/af_phonet.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/net/phonet/af_phonet.c
+++ b/net/phonet/af_phonet.c
@@ -377,6 +377,10 @@ static int phonet_rcv(struct sk_buff *sk
 	struct sockaddr_pn sa;
 	u16 len;
 
+	skb = skb_share_check(skb, GFP_ATOMIC);
+	if (!skb)
+		return NET_RX_DROP;
+
 	/* check we have at least a full Phonet header */
 	if (!pskb_pull(skb, sizeof(struct phonethdr)))
 		goto out;


Patches currently in stable-queue which might be from edumazet@google.com are

queue-4.4/ipv6-tcp-add-rcu-locking-in-tcp_v6_send_synack.patch
queue-4.4/ipv6-update-skb-csum-when-ce-mark-is-propagated.patch
queue-4.4/phonet-properly-unshare-skbs-in-phonet_rcv.patch
queue-4.4/tcp_yeah-don-t-set-ssthresh-below-2.patch