[3.11.y.z extended stable] Patch "macvtap: signal truncated packets" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    macvtap: signal truncated packets

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 8467960ce7ed715052116564a2148d611960aa43 Mon Sep 17 00:00:00 2001
From: Jason Wang <jasowang at redhat.com>
Date: Wed, 11 Dec 2013 13:08:34 +0800
Subject: macvtap: signal truncated packets

commit ce232ce01d61b184202bb185103d119820e1260c upstream.

macvtap_put_user() never return a value grater than iov length, this in fact
bypasses the truncated checking in macvtap_recvmsg(). Fix this by always
returning the size of packet plus the possible vlan header to let the trunca
checking work.

Cc: Vlad Yasevich <vyasevich at gmail.com>
Cc: Zhi Yong Wu <wuzhy at linux.vnet.ibm.com>
Cc: Michael S. Tsirkin <mst at redhat.com>
Signed-off-by: Jason Wang <jasowang at redhat.com>
Acked-by: Vlad Yasevich <vyasevich at gmail.com>
Acked-by: Michael S. Tsirkin <mst at redhat.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/macvtap.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index fa54f0e..8ce7075 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -873,7 +873,7 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q,
 	int ret;
 	int vnet_hdr_len = 0;
 	int vlan_offset = 0;
-	int copied;
+	int copied, total;

 	if (q->flags & IFF_VNET_HDR) {
 		struct virtio_net_hdr vnet_hdr;
@@ -888,7 +888,8 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q,
 		if (memcpy_toiovecend(iv, (void *)&vnet_hdr, 0, sizeof(vnet_hdr)))
 			return -EFAULT;
 	}
-	copied = vnet_hdr_len;
+	total = copied = vnet_hdr_len;
+	total += skb->len;

 	if (!vlan_tx_tag_present(skb))
 		len = min_t(int, skb->len, len);
@@ -903,6 +904,7 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q,

 		vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
 		len = min_t(int, skb->len + VLAN_HLEN, len);
+		total += VLAN_HLEN;

 		copy = min_t(int, vlan_offset, len);
 		ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy);
@@ -920,10 +922,9 @@ static ssize_t macvtap_put_user(struct macvtap_queue *q,
 	}

 	ret = skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len);
-	copied += len;

 done:
-	return ret ? ret : copied;
+	return ret ? ret : total;
 }

 static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb,
@@ -978,7 +979,7 @@ static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
 	}

 	ret = macvtap_do_read(q, iocb, iv, len, file->f_flags & O_NONBLOCK);
-	ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */
+	ret = min_t(ssize_t, ret, len);
 	if (ret > 0)
 		iocb->ki_pos = ret;
 out:
--
1.8.3.2