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, 78 insertions, 0 deletions

diff --git a/drivers/firmware/efi/reboot.c b/drivers/firmware/efi/reboot.c
new file mode 100644
index 000000000..ceae84c19
--- /dev/null
+++ b/drivers/firmware/efi/reboot.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2014 Intel Corporation; author Matt Fleming
+ * Copyright (c) 2014 Red Hat, Inc., Mark Salter <msalter@redhat.com>
+ */
+#include <linux/efi.h>
+#include <linux/reboot.h>
+
+static struct sys_off_handler *efi_sys_off_handler;
+
+int efi_reboot_quirk_mode = -1;
+
+void efi_reboot(enum reboot_mode reboot_mode, const char *__unused)
+{
+	const char *str[] = { "cold", "warm", "shutdown", "platform" };
+	int efi_mode, cap_reset_mode;
+
+	if (!efi_rt_services_supported(EFI_RT_SUPPORTED_RESET_SYSTEM))
+		return;
+
+	switch (reboot_mode) {
+	case REBOOT_WARM:
+	case REBOOT_SOFT:
+		efi_mode = EFI_RESET_WARM;
+		break;
+	default:
+		efi_mode = EFI_RESET_COLD;
+		break;
+	}
+
+	/*
+	 * If a quirk forced an EFI reset mode, always use that.
+	 */
+	if (efi_reboot_quirk_mode != -1)
+		efi_mode = efi_reboot_quirk_mode;
+
+	if (efi_capsule_pending(&cap_reset_mode)) {
+		if (efi_mode != cap_reset_mode)
+			printk(KERN_CRIT "efi: %s reset requested but pending "
+			       "capsule update requires %s reset... Performing "
+			       "%s reset.\n", str[efi_mode], str[cap_reset_mode],
+			       str[cap_reset_mode]);
+		efi_mode = cap_reset_mode;
+	}
+
+	efi.reset_system(efi_mode, EFI_SUCCESS, 0, NULL);
+}
+
+bool __weak efi_poweroff_required(void)
+{
+	return false;
+}
+
+static int efi_power_off(struct sys_off_data *data)
+{
+	efi.reset_system(EFI_RESET_SHUTDOWN, EFI_SUCCESS, 0, NULL);
+
+	return NOTIFY_DONE;
+}
+
+static int __init efi_shutdown_init(void)
+{
+	if (!efi_rt_services_supported(EFI_RT_SUPPORTED_RESET_SYSTEM))
+		return -ENODEV;
+
+	if (efi_poweroff_required()) {
+		/* SYS_OFF_PRIO_FIRMWARE + 1 so that it runs before acpi_power_off */
+		efi_sys_off_handler =
+			register_sys_off_handler(SYS_OFF_MODE_POWER_OFF,
+						 SYS_OFF_PRIO_FIRMWARE + 1,
+						 efi_power_off, NULL);
+		if (IS_ERR(efi_sys_off_handler))
+			return PTR_ERR(efi_sys_off_handler);
+	}
+
+	return 0;
+}
+late_initcall(efi_shutdown_init);