On Wed, Dec 11, 2013 at 01:08:34PM +0800, Jason Wang wrote:
> 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 <vyasev...@gmail.com>
> Cc: Zhi Yong Wu <wu...@linux.vnet.ibm.com>
> Cc: Michael S. Tsirkin <m...@redhat.com>
> Signed-off-by: Jason Wang <jasow...@redhat.com>
Acked-by: Michael S. Tsirkin <m...@redhat.com>
> ---
> Changes from V2:
> - use total as the bytes of packet returned
> Changes from V1:
> - increase total unconditionally
> - do not move the structure veth out of the vlan handling block
> ---
> 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 957cc5c..2a89da0 100644
> --- a/drivers/net/macvtap.c
> +++ b/drivers/net/macvtap.c
> @@ -770,7 +770,7 @@ 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;
> @@ -785,7 +785,8 @@ 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);
> @@ -800,6 +801,7 @@ 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);
> @@ -817,10 +819,9 @@ 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,
> @@ -875,7 +876,7 @@ 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
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