[PATCH 3.12 09/77] macvtap: signal truncated packets
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2014-01-14 00:28:28
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3.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Wang <redacted> [ Upstream commit ce232ce01d61b184202bb185103d119820e1260c ] 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 <redacted> Cc: Zhi Yong Wu <redacted> Cc: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jason Wang <redacted> Acked-by: Vlad Yasevich <redacted> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/net/macvtap.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c@@ -770,7 +770,7 @@ static ssize_t macvtap_put_user(struct m 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 m 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 m 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 m } 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 k } 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: