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![Juergen Gross](/assets/img/avatar_default.png)
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)
141 lines
4.7 KiB
C
141 lines
4.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _XEN_EVENTS_H
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#define _XEN_EVENTS_H
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#ifdef CONFIG_PCI_MSI
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#include <linux/msi.h>
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#endif
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#include <xen/interface/event_channel.h>
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#include <asm/xen/hypercall.h>
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#include <asm/xen/events.h>
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struct xenbus_device;
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unsigned xen_evtchn_nr_channels(void);
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int bind_evtchn_to_irq(evtchn_port_t evtchn);
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int bind_evtchn_to_irq_lateeoi(evtchn_port_t evtchn);
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int bind_evtchn_to_irqhandler(evtchn_port_t evtchn,
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irq_handler_t handler,
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unsigned long irqflags, const char *devname,
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void *dev_id);
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int bind_evtchn_to_irqhandler_lateeoi(evtchn_port_t evtchn,
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irq_handler_t handler,
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unsigned long irqflags, const char *devname,
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void *dev_id);
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int bind_virq_to_irq(unsigned int virq, unsigned int cpu, bool percpu);
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int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
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irq_handler_t handler,
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unsigned long irqflags, const char *devname,
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void *dev_id);
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int bind_ipi_to_irqhandler(enum ipi_vector ipi,
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unsigned int cpu,
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irq_handler_t handler,
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unsigned long irqflags,
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const char *devname,
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void *dev_id);
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int bind_interdomain_evtchn_to_irq_lateeoi(struct xenbus_device *dev,
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evtchn_port_t remote_port);
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int bind_interdomain_evtchn_to_irqhandler_lateeoi(struct xenbus_device *dev,
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evtchn_port_t remote_port,
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irq_handler_t handler,
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unsigned long irqflags,
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const char *devname,
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void *dev_id);
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/*
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* Common unbind function for all event sources. Takes IRQ to unbind from.
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* Automatically closes the underlying event channel (even for bindings
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* made with bind_evtchn_to_irqhandler()).
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*/
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void unbind_from_irqhandler(unsigned int irq, void *dev_id);
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/*
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* Send late EOI for an IRQ bound to an event channel via one of the *_lateeoi
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* functions above.
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*/
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void xen_irq_lateeoi(unsigned int irq, unsigned int eoi_flags);
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/* Signal an event was spurious, i.e. there was no action resulting from it. */
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#define XEN_EOI_FLAG_SPURIOUS 0x00000001
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#define XEN_IRQ_PRIORITY_MAX EVTCHN_FIFO_PRIORITY_MAX
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#define XEN_IRQ_PRIORITY_DEFAULT EVTCHN_FIFO_PRIORITY_DEFAULT
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#define XEN_IRQ_PRIORITY_MIN EVTCHN_FIFO_PRIORITY_MIN
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int xen_set_irq_priority(unsigned irq, unsigned priority);
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/*
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* Allow extra references to event channels exposed to userspace by evtchn
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*/
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int evtchn_make_refcounted(evtchn_port_t evtchn);
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int evtchn_get(evtchn_port_t evtchn);
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void evtchn_put(evtchn_port_t evtchn);
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void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector);
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void rebind_evtchn_irq(evtchn_port_t evtchn, int irq);
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int xen_set_affinity_evtchn(struct irq_desc *desc, unsigned int tcpu);
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static inline void notify_remote_via_evtchn(evtchn_port_t port)
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{
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struct evtchn_send send = { .port = port };
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(void)HYPERVISOR_event_channel_op(EVTCHNOP_send, &send);
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}
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void notify_remote_via_irq(int irq);
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void xen_irq_resume(void);
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/* Clear an irq's pending state, in preparation for polling on it */
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void xen_clear_irq_pending(int irq);
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void xen_set_irq_pending(int irq);
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bool xen_test_irq_pending(int irq);
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/* Poll waiting for an irq to become pending. In the usual case, the
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irq will be disabled so it won't deliver an interrupt. */
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void xen_poll_irq(int irq);
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/* Poll waiting for an irq to become pending with a timeout. In the usual case,
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* the irq will be disabled so it won't deliver an interrupt. */
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void xen_poll_irq_timeout(int irq, u64 timeout);
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/* Determine the IRQ which is bound to an event channel */
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unsigned int irq_from_evtchn(evtchn_port_t evtchn);
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int irq_from_virq(unsigned int cpu, unsigned int virq);
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evtchn_port_t evtchn_from_irq(unsigned irq);
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int xen_set_callback_via(uint64_t via);
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void xen_evtchn_do_upcall(struct pt_regs *regs);
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void xen_hvm_evtchn_do_upcall(void);
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/* Bind a pirq for a physical interrupt to an irq. */
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int xen_bind_pirq_gsi_to_irq(unsigned gsi,
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unsigned pirq, int shareable, char *name);
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#ifdef CONFIG_PCI_MSI
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/* Allocate a pirq for a MSI style physical interrupt. */
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int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc);
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/* Bind an PSI pirq to an irq. */
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int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
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int pirq, int nvec, const char *name, domid_t domid);
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#endif
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/* De-allocates the above mentioned physical interrupt. */
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int xen_destroy_irq(int irq);
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/* Return irq from pirq */
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int xen_irq_from_pirq(unsigned pirq);
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/* Return the pirq allocated to the irq. */
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int xen_pirq_from_irq(unsigned irq);
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/* Return the irq allocated to the gsi */
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int xen_irq_from_gsi(unsigned gsi);
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/* Determine whether to ignore this IRQ if it is passed to a guest. */
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int xen_test_irq_shared(int irq);
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/* initialize Xen IRQ subsystem */
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void xen_init_IRQ(void);
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#endif /* _XEN_EVENTS_H */
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