From ce232ce01d61b184202bb185103d119820e1260c Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Wed, 11 Dec 2013 13:08:34 +0800 Subject: [PATCH] macvtap: signal truncated packets 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 Acked-by: Vlad Yasevich Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller --- 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: -- 2.7.4