• Toshiaki Makita's avatar
    vlan: Fix vlan insertion for packets without ethernet header · c769accd
    Toshiaki Makita authored
    In some situation vlan packets do not have ethernet headers. One example
    is packets from tun devices. Users can specify vlan protocol in tun_pi
    field instead of IP protocol. When we have a vlan device with reorder_hdr
    disabled on top of the tun device, such packets from tun devices are
    untagged in skb_vlan_untag() and vlan headers will be inserted back in
    vlan_insert_inner_tag().
    
    vlan_insert_inner_tag() however did not expect packets without ethernet
    headers, so in such a case size argument for memmove() underflowed.
    
    We don't need to copy headers for packets which do not have preceding
    headers of vlan headers, so skip memmove() in that case.
    Also don't write vlan protocol in skb->data when it does not have enough
    room for it.
    
    Fixes: cbe7128c ("vlan: Fix out of order vlan headers with reorder header off")
    Signed-off-by: default avatarToshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    c769accd
if_vlan.h 18.6 KB