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authorJuergen Gross <jgross@suse.com>2021-12-16 08:24:08 +0100
committerJuergen Gross <jgross@suse.com>2021-12-16 08:24:08 +0100
commitfe415186b43df0db1f17fa3a46275fd92107fe71 (patch)
tree748fdfc2bdd32d5f9f176b6d699161d6725f1433 /include/xen
parentb27d47950e481f292c0a5ad57357edb9d95d03ba (diff)
xen/console: harden hvc_xen against event channel storms
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: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> --- V2: - slightly adapt spurious irq detection (Jan Beulich) V3: - fix spurious irq detection (Jan Beulich)
Diffstat (limited to 'include/xen')
-rw-r--r--include/xen/events.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/xen/events.h b/include/xen/events.h
index c204262d9fc2..344081e71584 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -17,6 +17,7 @@ struct xenbus_device;
unsigned xen_evtchn_nr_channels(void);
int bind_evtchn_to_irq(evtchn_port_t evtchn);
+int bind_evtchn_to_irq_lateeoi(evtchn_port_t evtchn);
int bind_evtchn_to_irqhandler(evtchn_port_t evtchn,
irq_handler_t handler,
unsigned long irqflags, const char *devname,