bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 56 insertions, 0 deletions

diff --git a/security/integrity/efi_secureboot.c b/security/integrity/efi_secureboot.c
new file mode 100644
index 000000000..bfd4260a8
--- /dev/null
+++ b/security/integrity/efi_secureboot.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: GPL-1.0+
+/*
+ * Copyright (C) 2018 IBM Corporation
+ */
+#include <linux/efi.h>
+#include <linux/secure_boot.h>
+#include <asm/efi.h>
+
+#ifndef arch_efi_boot_mode
+#define arch_efi_boot_mode efi_secureboot_mode_unset
+#endif
+
+static enum efi_secureboot_mode get_sb_mode(void)
+{
+	enum efi_secureboot_mode mode;
+
+	if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE)) {
+		pr_info("integrity: secureboot mode unknown, no efi\n");
+		return efi_secureboot_mode_unknown;
+	}
+
+	mode = efi_get_secureboot_mode(efi.get_variable);
+	if (mode == efi_secureboot_mode_disabled)
+		pr_info("integrity: secureboot mode disabled\n");
+	else if (mode == efi_secureboot_mode_unknown)
+		pr_info("integrity: secureboot mode unknown\n");
+	else
+		pr_info("integrity: secureboot mode enabled\n");
+	return mode;
+}
+
+/*
+ * Query secure boot status
+ *
+ * Note don't call this function too early e.g. in __setup hook otherwise the
+ * kernel may hang when calling efi_get_secureboot_mode.
+ *
+ */
+bool arch_get_secureboot(void)
+{
+	static enum efi_secureboot_mode sb_mode;
+	static bool initialized;
+
+	if (!initialized && efi_enabled(EFI_BOOT)) {
+		sb_mode = arch_efi_boot_mode;
+
+		if (sb_mode == efi_secureboot_mode_unset)
+			sb_mode = get_sb_mode();
+		initialized = true;
+	}
+
+	if (sb_mode == efi_secureboot_mode_enabled)
+		return true;
+	else
+		return false;
+}