From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH net V2 2/2] macvtap: signal truncated packets Date: Tue, 10 Dec 2013 17:29:51 +0200 Message-ID: <20131210152951.GE25293@redhat.com> References: <1386654586-18151-1-git-send-email-jasowang@redhat.com> <1386654586-18151-2-git-send-email-jasowang@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Vlad Yasevich , Zhi Yong Wu To: Jason Wang Return-path: Content-Disposition: inline In-Reply-To: <1386654586-18151-2-git-send-email-jasowang@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Tue, Dec 10, 2013 at 01:49:46PM +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 > Cc: Zhi Yong Wu > Cc: Michael S. Tsirkin > Signed-off-by: Jason Wang > --- > Changes from v1: > - increase total unconditionally > - do not move the structure veth out of the vlan handling block > --- > drivers/net/macvtap.c | 19 ++++++++++--------- > 1 file changed, 10 insertions(+), 9 deletions(-) > > diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c > index 957cc5c..ded4b2c 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, offset; > > 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; > + offset = copied = vnet_hdr_len; > + copied += skb->len; > > if (!vlan_tx_tag_present(skb)) > len = min_t(int, skb->len, len); > @@ -800,24 +801,24 @@ 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); > + copied += VLAN_HLEN; > > copy = min_t(int, vlan_offset, len); > - ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy); > + ret = skb_copy_datagram_const_iovec(skb, 0, iv, offset, copy); > len -= copy; > - copied += copy; > + offset += copy; > if (ret || !len) > goto done; > > copy = min_t(int, sizeof(veth), len); > - ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy); > + ret = memcpy_toiovecend(iv, (void *)&veth, offset, copy); > len -= copy; > - copied += copy; > + offset += copy; > if (ret || !len) > goto done; > } > > - ret = skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len); > - copied += len; > + ret = skb_copy_datagram_const_iovec(skb, vlan_offset, iv, offset, len); > > done: > return ret ? ret : copied; I commented on this already. copied is how much we copied, so its value is correct. You want to name the new one total_len or something along these lines and return it. > @@ -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