Patch "packet: do skb_probe_transport_header when we actually have data" has been added to the 4.2-stable tree

Patch "packet: do skb_probe_transport_header when we actually have data" has been added to the 4.2-stable tree

[gregkh]

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

    packet: do skb_probe_transport_header when we actually have data

to the 4.2-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:
     packet-do-skb_probe_transport_header-when-we-actually-have-data.patch
and it can be found in the queue-4.2 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 Fri Dec 11 11:38:35 EST 2015
From: Daniel Borkmann <daniel@iogearbox.net>
Date: Wed, 11 Nov 2015 23:25:40 +0100
Subject: packet: do skb_probe_transport_header when we actually have data

From: Daniel Borkmann <daniel@iogearbox.net>

[ Upstream commit efdfa2f7848f64517008136fb41f53c4a1faf93a ]

In tpacket_fill_skb() commit c1aad275b029 ("packet: set transport
header before doing xmit") and later on 40893fd0fd4e ("net: switch
to use skb_probe_transport_header()") was probing for a transport
header on the skb from a ring buffer slot, but at a time, where
the skb has _not even_ been filled with data yet. So that call into
the flow dissector is pretty useless. Lets do it after we've set
up the skb frags.

Fixes: c1aad275b029 ("packet: set transport header before doing xmit")
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/packet/af_packet.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2249,8 +2249,6 @@ static int tpacket_fill_skb(struct packe
 	skb_reserve(skb, hlen);
 	skb_reset_network_header(skb);
 
-	if (!packet_use_direct_xmit(po))
-		skb_probe_transport_header(skb, 0);
 	if (unlikely(po->tp_tx_has_off)) {
 		int off_min, off_max, off;
 		off_min = po->tp_hdrlen - sizeof(struct sockaddr_ll);
@@ -2330,6 +2328,9 @@ static int tpacket_fill_skb(struct packe
 		len = ((to_write > len_max) ? len_max : to_write);
 	}
 
+	if (!packet_use_direct_xmit(po))
+		skb_probe_transport_header(skb, 0);
+
 	return tp_len;
 }
 


Patches currently in stable-queue which might be from daniel@iogearbox.net are

queue-4.2/packet-infer-protocol-from-ethernet-header-if-unset.patch
queue-4.2/bpf-array-fix-heap-out-of-bounds-access-when-updating-elements.patch
queue-4.2/ipv6-sctp-implement-sctp_v6_destroy_sock.patch
queue-4.2/packet-only-allow-extra-vlan-len-on-ethernet-devices.patch
queue-4.2/net-scm-fix-pax-detected-msg_controllen-overflow-in-scm_detach_fds.patch
queue-4.2/packet-fix-tpacket_snd-max-frame-len.patch
queue-4.2/packet-always-probe-for-transport-header.patch
queue-4.2/packet-do-skb_probe_transport_header-when-we-actually-have-data.patch
queue-4.2/tools-net-use-include-uapi-with-__exported_headers__.patch