Patch "packet: round up linear to header len" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

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

    packet: round up linear to header len

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:
     packet-round-up-linear-to-header-len.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 Feb 14 16:29:59 PST 2017
From: Willem de Bruijn <willemb@google.com>
Date: Tue, 7 Feb 2017 15:57:21 -0500
Subject: packet: round up linear to header len

From: Willem de Bruijn <willemb@google.com>


[ Upstream commit 57031eb794906eea4e1c7b31dc1e2429c0af0c66 ]

Link layer protocols may unconditionally pull headers, as Ethernet
does in eth_type_trans. Ensure that the entire link layer header
always lies in the skb linear segment. tpacket_snd has such a check.
Extend this to packet_snd.

Variable length link layer headers complicate the computation
somewhat. Here skb->len may be smaller than dev->hard_header_len.

Round up the linear length to be at least as long as the smallest of
the two.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/packet/af_packet.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2637,7 +2637,7 @@ static int packet_snd(struct socket *soc
 	int vnet_hdr_len;
 	struct packet_sock *po = pkt_sk(sk);
 	unsigned short gso_type = 0;
-	int hlen, tlen;
+	int hlen, tlen, linear;
 	int extra_len = 0;
 	ssize_t n;
 
@@ -2741,8 +2741,9 @@ static int packet_snd(struct socket *soc
 	err = -ENOBUFS;
 	hlen = LL_RESERVED_SPACE(dev);
 	tlen = dev->needed_tailroom;
-	skb = packet_alloc_skb(sk, hlen + tlen, hlen, len,
-			       __virtio16_to_cpu(vio_le(), vnet_hdr.hdr_len),
+	linear = __virtio16_to_cpu(vio_le(), vnet_hdr.hdr_len);
+	linear = max(linear, min_t(int, len, dev->hard_header_len));
+	skb = packet_alloc_skb(sk, hlen + tlen, hlen, len, linear,
 			       msg->msg_flags & MSG_DONTWAIT, &err);
 	if (skb == NULL)
 		goto out_unlock;


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

queue-4.4/packet-round-up-linear-to-header-len.patch
queue-4.4/tun-read-vnet_hdr_sz-once.patch
queue-4.4/ipv6-fix-ip6_tnl_parse_tlv_enc_lim.patch
queue-4.4/net-introduce-device-min_header_len.patch
queue-4.4/macvtap-read-vnet_hdr_size-once.patch