• Eric Dumazet's avatar
    vxlan: test dev->flags & IFF_UP before calling netif_rx() · 60652bba
    Eric Dumazet authored
    [ Upstream commit 4179cb5a ]
    
    netif_rx() must be called under a strict contract.
    
    At device dismantle phase, core networking clears IFF_UP
    and flush_all_backlogs() is called after rcu grace period
    to make sure no incoming packet might be in a cpu backlog
    and still referencing the device.
    
    Most drivers call netif_rx() from their interrupt handler,
    and since the interrupts are disabled at device dismantle,
    netif_rx() does not have to check dev->flags & IFF_UP
    
    Virtual drivers do not have this guarantee, and must
    therefore make the check themselves.
    
    Otherwise we risk use-after-free and/or crashes.
    
    Note this patch also fixes a small issue that came
    with commit ce6502a8 ("vxlan: fix a use after free
    in vxlan_encap_bypass"), since the dev->stats.rx_dropped
    change was done on the wrong device.
    
    Fixes: d342894c ("vxlan: virtual extensible lan")
    Fixes: ce6502a8 ("vxlan: fix a use after free in vxlan_encap_bypass")
    Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
    Cc: Petr Machata <petrm@mellanox.com>
    Cc: Ido Schimmel <idosch@mellanox.com>
    Cc: Roopa Prabhu <roopa@cumulusnetworks.com>
    Cc: Stefano Brivio <sbrivio@redhat.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
    60652bba
vxlan.c 100 KB