selftests/bpf: Test packet range of pointers sharing an idgrafted

Add tests where two packet pointers share an id and tightening one
pointer's umax from its var_off would put it less than their constant
distance from the other's umax: with an index & 0x38 capped at 50, the
base pointer keeps umax 50, so the pointer 8 bytes further on must keep
umax 58, even though its known bits allow at most 56.

These refused a valid program or accepted an out-of-bounds access before
the fix:

- check the advanced copy, load through the base: valid, was refused;
- check the base, load the byte at base + 1 through a copy advanced by
  8: was accepted;
- check base + 4, load 4 bytes at base + 2 through base + 8: reads two
  bytes past the checked range, was accepted;
- the same as the second with data_meta pointers checked against data:
  was accepted.

These pass with and without the fix and cover nearby paths:

- subtract an unknown scalar from a checked pointer and load below it
  (the range is kept across a new id);
- reach a load through two paths whose checks cover 8 and 7 bytes after
  the loaded pointer; the second path must not be pruned by the first;
- spill a copy of a pointer, check the pointer, fill the copy and load
  one byte past the checked range: the load is refused, and the copy
  has the range of the check.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20261001145255.855630-2-alexei.starovoitov@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

1 files changed, 149 insertions, 0 deletions

diff --git a/include/xen/events.h b/include/xen/events.h
new file mode 100644
index 000000000..de5da58a0
--- /dev/null
+++ b/include/xen/events.h
@@ -0,0 +1,149 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _XEN_EVENTS_H
+#define _XEN_EVENTS_H
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#ifdef CONFIG_PCI_MSI
+#include <linux/msi.h>
+#endif
+
+#include <xen/interface/event_channel.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/events.h>
+
+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,
+			      void *dev_id);
+int bind_evtchn_to_irqhandler_lateeoi(evtchn_port_t evtchn,
+			      irq_handler_t handler,
+			      unsigned long irqflags, const char *devname,
+			      void *dev_id);
+int bind_virq_to_irq(unsigned int virq, unsigned int cpu, bool percpu);
+int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
+			    irq_handler_t handler,
+			    unsigned long irqflags, const char *devname,
+			    void *dev_id);
+int bind_ipi_to_irqhandler(enum ipi_vector ipi,
+			   unsigned int cpu,
+			   irq_handler_t handler,
+			   unsigned long irqflags,
+			   const char *devname,
+			   void *dev_id);
+int bind_interdomain_evtchn_to_irq_lateeoi(struct xenbus_device *dev,
+					   evtchn_port_t remote_port);
+int bind_interdomain_evtchn_to_irqhandler_lateeoi(struct xenbus_device *dev,
+						  evtchn_port_t remote_port,
+						  irq_handler_t handler,
+						  unsigned long irqflags,
+						  const char *devname,
+						  void *dev_id);
+
+/*
+ * Common unbind function for all event sources. Takes IRQ to unbind from.
+ * Automatically closes the underlying event channel (even for bindings
+ * made with bind_evtchn_to_irqhandler()).
+ */
+void unbind_from_irqhandler(unsigned int irq, void *dev_id);
+
+/*
+ * Send late EOI for an IRQ bound to an event channel via one of the *_lateeoi
+ * functions above.
+ */
+void xen_irq_lateeoi(unsigned int irq, unsigned int eoi_flags);
+/* Signal an event was spurious, i.e. there was no action resulting from it. */
+#define XEN_EOI_FLAG_SPURIOUS	0x00000001
+
+#define XEN_IRQ_PRIORITY_MAX     EVTCHN_FIFO_PRIORITY_MAX
+#define XEN_IRQ_PRIORITY_DEFAULT EVTCHN_FIFO_PRIORITY_DEFAULT
+#define XEN_IRQ_PRIORITY_MIN     EVTCHN_FIFO_PRIORITY_MIN
+int xen_set_irq_priority(unsigned irq, unsigned priority);
+
+/*
+ * Allow extra references to event channels exposed to userspace by evtchn
+ */
+int evtchn_make_refcounted(evtchn_port_t evtchn, bool is_static);
+int evtchn_get(evtchn_port_t evtchn);
+void evtchn_put(evtchn_port_t evtchn);
+
+void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector);
+void rebind_evtchn_irq(evtchn_port_t evtchn, int irq);
+
+static inline void notify_remote_via_evtchn(evtchn_port_t port)
+{
+	struct evtchn_send send = { .port = port };
+	(void)HYPERVISOR_event_channel_op(EVTCHNOP_send, &send);
+}
+
+void notify_remote_via_irq(int irq);
+
+void xen_irq_resume(void);
+
+/* Clear an irq's pending state, in preparation for polling on it */
+void xen_clear_irq_pending(int irq);
+bool xen_test_irq_pending(int irq);
+
+/* Poll waiting for an irq to become pending.  In the usual case, the
+   irq will be disabled so it won't deliver an interrupt. */
+void xen_poll_irq(int irq);
+
+/* Poll waiting for an irq to become pending with a timeout.  In the usual case,
+ * the irq will be disabled so it won't deliver an interrupt. */
+void xen_poll_irq_timeout(int irq, u64 timeout);
+
+/* Determine the IRQ which is bound to an event channel */
+unsigned int irq_from_evtchn(evtchn_port_t evtchn);
+int irq_evtchn_from_virq(unsigned int cpu, unsigned int virq,
+			 evtchn_port_t *evtchn);
+
+int xen_set_callback_via(uint64_t via);
+int xen_evtchn_do_upcall(void);
+
+/* Bind a pirq for a physical interrupt to an irq. */
+int xen_bind_pirq_gsi_to_irq(unsigned gsi,
+			     unsigned pirq, int shareable, char *name);
+
+#ifdef CONFIG_PCI_MSI
+/* Allocate a pirq for a MSI style physical interrupt. */
+int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc);
+/* Bind an PSI pirq to an irq. */
+int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
+			     int pirq, int nvec, const char *name, domid_t domid);
+#endif
+
+/* De-allocates the above mentioned physical interrupt. */
+int xen_destroy_irq(int irq);
+
+/* Return the pirq allocated to the irq. */
+int xen_pirq_from_irq(unsigned irq);
+
+/* Return the irq allocated to the gsi */
+int xen_irq_from_gsi(unsigned gsi);
+
+/* Determine whether to ignore this IRQ if it is passed to a guest. */
+int xen_test_irq_shared(int irq);
+
+/* initialize Xen IRQ subsystem */
+void xen_init_IRQ(void);
+
+irqreturn_t xen_debug_interrupt(int irq, void *dev_id);
+
+static inline void xen_evtchn_close(evtchn_port_t port)
+{
+	struct evtchn_close close;
+
+	close.port = port;
+	if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
+		BUG();
+}
+
+extern bool xen_fifo_events;
+
+#endif	/* _XEN_EVENTS_H */