• J
    xen/console: harden hvc_xen against event channel storms · fe415186
    Juergen Gross 提交于
    The Xen console driver is still vulnerable for an attack via excessive
    number of events sent by the backend. Fix that by using a lateeoi event
    channel.
    
    For the normal domU initial console this requires the introduction of
    bind_evtchn_to_irq_lateeoi() as there is no xenbus device available
    at the time the event channel is bound to the irq.
    
    As the decision whether an interrupt was spurious or not requires to
    test for bytes having been read from the backend, move sending the
    event into the if statement, as sending an event without having found
    any bytes to be read is making no sense at all.
    
    This is part of XSA-391
    Signed-off-by: NJuergen Gross <jgross@suse.com>
    Reviewed-by: NJan Beulich <jbeulich@suse.com>
    ---
    V2:
    - slightly adapt spurious irq detection (Jan Beulich)
    V3:
    - fix spurious irq detection (Jan Beulich)
    fe415186
events_base.c 52.5 KB