RFC

include/linux/lsm_hooks.h

@@ -1524,6 +1524,7 @@ union security_list_options {
 	#define LSM_HOOK(RET, DEFAULT, NAME, ...) RET (*NAME)(__VA_ARGS__);
 	#include "lsm_hook_defs.h"
 	#undef LSM_HOOK
+	void *generic_func;
 };
 
 struct security_hook_heads {

include/linux/lsm_static_call.h

@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright (C) 2020 Google LLC.
+ */
+
+#ifndef __LINUX_LSM_STATIC_CALL_H
+#define __LINUX_LSM_STATIC_CALL_H
+
+/*
+ * Static slots are used in security/security.c to avoid costly 
+ * indirect calls by replacing them with static calls.
+ * The number of static calls for each LSM hook is fixed.
+ */
+#define SECURITY_STATIC_SLOT_COUNT 11
+
+/*
+ * Identifier for the LSM static slots.
+ * HOOK is an LSM hook as defined in linux/lsm_hookdefs.h
+ * IDX is the index of the slot. 0 <= NUM < SECURITY_STATIC_SLOT_COUNT
+ */
+#define STATIC_SLOT(HOOK, IDX) security_static_slot_##HOOK##_##IDX
+
+/*
+ * Call the macro M for each LSM hook slot.
+ * M should take as first argument the index and then
+ * the same __VA_ARGS__
+ * Essentially, this will expand to:
+ *	M(0, ...)
+ *	M(1, ...)
+ *	M(2, ...)
+ *	...
+ * Note that no trailing semicolon is placed so M should be defined
+ * accordingly.
+ * This adapts to a change to SECURITY_STATIC_SLOT_COUNT.
+ */
+#define SECURITY_FOREACH_STATIC_SLOT(M, ...)		\
+	UNROLL_MACRO_LOOP(SECURITY_STATIC_SLOT_COUNT, M, __VA_ARGS__)
+
+/*
+ * Intermediate macros to expand SECURITY_STATIC_SLOT_COUNT
+ */
+#define UNROLL_MACRO_LOOP(N, MACRO, ...)		\
+	_UNROLL_MACRO_LOOP(N, MACRO, __VA_ARGS__)
+
+#define _UNROLL_MACRO_LOOP(N, MACRO, ...)		\
+	__UNROLL_MACRO_LOOP(N, MACRO, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP(N, MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_##N(MACRO, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_0(MACRO, ...)
+
+#define __UNROLL_MACRO_LOOP_1(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_0(MACRO, __VA_ARGS__)	\
+	MACRO(0, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_2(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_1(MACRO, __VA_ARGS__)	\
+	MACRO(1, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_3(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_2(MACRO, __VA_ARGS__)	\
+	MACRO(2, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_4(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_3(MACRO, __VA_ARGS__)	\
+	MACRO(3, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_5(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_4(MACRO, __VA_ARGS__)	\
+	MACRO(4, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_6(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_5(MACRO, __VA_ARGS__)	\
+	MACRO(5, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_7(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_6(MACRO, __VA_ARGS__)	\
+	MACRO(6, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_8(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_7(MACRO, __VA_ARGS__)	\
+	MACRO(7, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_9(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_8(MACRO, __VA_ARGS__)	\
+	MACRO(8, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_10(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_9(MACRO, __VA_ARGS__)	\
+	MACRO(9, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_11(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_10(MACRO, __VA_ARGS__)	\
+	MACRO(10, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_12(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_11(MACRO, __VA_ARGS__)	\
+	MACRO(11, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_13(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_12(MACRO, __VA_ARGS__)	\
+	MACRO(12, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_14(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_13(MACRO, __VA_ARGS__)	\
+	MACRO(13, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_15(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_14(MACRO, __VA_ARGS__)	\
+	MACRO(14, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_16(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_15(MACRO, __VA_ARGS__)	\
+	MACRO(15, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_17(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_16(MACRO, __VA_ARGS__)	\
+	MACRO(16, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_18(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_17(MACRO, __VA_ARGS__)	\
+	MACRO(17, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_19(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_18(MACRO, __VA_ARGS__)	\
+	MACRO(18, __VA_ARGS__)
+
+#define __UNROLL_MACRO_LOOP_20(MACRO, ...)		\
+	__UNROLL_MACRO_LOOP_19(MACRO, __VA_ARGS__)	\
+	MACRO(19, __VA_ARGS__)
+
+#endif /* __LINUX_LSM_STATIC_CALL_H */