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, 117 insertions, 0 deletions

diff --git a/drivers/acpi/container.c b/drivers/acpi/container.c
new file mode 100644
index 000000000..f138a4335
--- /dev/null
+++ b/drivers/acpi/container.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * container.c  - ACPI Generic Container Driver
+ *
+ * Copyright (C) 2004 Anil S Keshavamurthy (anil.s.keshavamurthy@intel.com)
+ * Copyright (C) 2004 Keiichiro Tokunaga (tokunaga.keiich@jp.fujitsu.com)
+ * Copyright (C) 2004 Motoyuki Ito (motoyuki@soft.fujitsu.com)
+ * Copyright (C) 2004 FUJITSU LIMITED
+ * Copyright (C) 2004, 2013 Intel Corp.
+ * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ */
+#include <linux/acpi.h>
+#include <linux/container.h>
+
+#include "internal.h"
+
+static const struct acpi_device_id container_device_ids[] = {
+	{"ACPI0004", 0},
+	{"PNP0A05", 0},
+	{"PNP0A06", 0},
+	{"", 0},
+};
+
+#ifdef CONFIG_ACPI_CONTAINER
+
+static int check_offline(struct acpi_device *adev, void *not_used)
+{
+	if (acpi_scan_is_offline(adev, false))
+		return 0;
+
+	return -EBUSY;
+}
+
+static int acpi_container_offline(struct container_dev *cdev)
+{
+	/* Check all of the dependent devices' physical companions. */
+	return acpi_dev_for_each_child(ACPI_COMPANION(&cdev->dev), check_offline, NULL);
+}
+
+static void acpi_container_release(struct device *dev)
+{
+	kfree(to_container_dev(dev));
+}
+
+static int container_device_attach(struct acpi_device *adev,
+				   const struct acpi_device_id *not_used)
+{
+	struct container_dev *cdev;
+	struct device *dev;
+	int ret;
+
+	if (adev->flags.is_dock_station)
+		return 0;
+
+	cdev = kzalloc_obj(*cdev);
+	if (!cdev)
+		return -ENOMEM;
+
+	cdev->offline = acpi_container_offline;
+	dev = &cdev->dev;
+	dev->bus = &container_subsys;
+	dev_set_name(dev, "%s", dev_name(&adev->dev));
+	ACPI_COMPANION_SET(dev, adev);
+	dev->release = acpi_container_release;
+	ret = device_register(dev);
+	if (ret) {
+		put_device(dev);
+		return ret;
+	}
+	adev->driver_data = dev;
+	return 1;
+}
+
+static void container_device_detach(struct acpi_device *adev)
+{
+	struct device *dev = acpi_driver_data(adev);
+
+	adev->driver_data = NULL;
+	if (dev)
+		device_unregister(dev);
+}
+
+static void container_device_online(struct acpi_device *adev)
+{
+	struct device *dev = acpi_driver_data(adev);
+
+	kobject_uevent(&dev->kobj, KOBJ_ONLINE);
+}
+
+static struct acpi_scan_handler container_handler = {
+	.ids = container_device_ids,
+	.attach = container_device_attach,
+	.detach = container_device_detach,
+	.hotplug = {
+		.enabled = true,
+		.demand_offline = true,
+		.notify_online = container_device_online,
+	},
+};
+
+void __init acpi_container_init(void)
+{
+	acpi_scan_add_handler(&container_handler);
+}
+
+#else
+
+static struct acpi_scan_handler container_handler = {
+	.ids = container_device_ids,
+};
+
+void __init acpi_container_init(void)
+{
+	acpi_scan_add_handler_with_hotplug(&container_handler, "container");
+}
+
+#endif /* CONFIG_ACPI_CONTAINER */