• Ido Schimmel's avatar
    bridge: Fix incorrect re-injection of LLDP packets · baedbe55
    Ido Schimmel authored
    Commit 8626c56c ("bridge: fix potential use-after-free when hook
    returns QUEUE or STOLEN verdict") caused LLDP packets arriving through a
    bridge port to be re-injected to the Rx path with skb->dev set to the
    bridge device, but this breaks the lldpad daemon.
    
    The lldpad daemon opens a packet socket with protocol set to ETH_P_LLDP
    for any valid device on the system, which doesn't not include soft
    devices such as bridge and VLAN.
    
    Since packet sockets (ptype_base) are processed in the Rx path after the
    Rx handler, LLDP packets with skb->dev set to the bridge device never
    reach the lldpad daemon.
    
    Fix this by making the bridge's Rx handler re-inject LLDP packets with
    RX_HANDLER_PASS, which effectively restores the behaviour prior to the
    mentioned commit.
    
    This means netfilter will never receive LLDP packets coming through a
    bridge port, as I don't see a way in which we can have okfn() consume
    the packet without breaking existing behaviour. I've already carried out
    a similar fix for STP packets in commit 56fae404 ("bridge: Fix
    incorrect re-injection of STP packets").
    
    Fixes: 8626c56c ("bridge: fix potential use-after-free when hook returns QUEUE or STOLEN verdict")
    Signed-off-by: default avatarIdo Schimmel <idosch@mellanox.com>
    Reviewed-by: default avatarJiri Pirko <jiri@mellanox.com>
    Cc: Florian Westphal <fw@strlen.de>
    Cc: John Fastabend <john.fastabend@gmail.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    baedbe55
br_input.c 8.35 KB