From d51e783c17bab0c139bf78d6bd9d1f66673f7903 Mon Sep 17 00:00:00 2001 From: KP Singh Date: Fri, 16 Aug 2024 17:43:06 +0200 Subject: lsm: count the LSMs enabled at compile time These macros are a clever trick to determine a count of the number of LSMs that are enabled in the config to ascertain the maximum number of static calls that need to be configured per LSM hook. Without this one would need to generate static calls for the total number of LSMs in the kernel (even if they are not compiled) times the number of LSM hooks which ends up being quite wasteful. Tested-by: Guenter Roeck Suggested-by: Kui-Feng Lee Suggested-by: Andrii Nakryiko Reviewed-by: Kees Cook Reviewed-by: Casey Schaufler Reviewed-by: John Johansen Acked-by: Casey Schaufler Acked-by: Song Liu Acked-by: Andrii Nakryiko Nacked-by: Tetsuo Handa Signed-off-by: KP Singh [PM: added IPE to the count during merge] Signed-off-by: Paul Moore --- include/linux/args.h | 6 +-- include/linux/lsm_count.h | 135 ++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 138 insertions(+), 3 deletions(-) create mode 100644 include/linux/lsm_count.h (limited to 'include/linux') diff --git a/include/linux/args.h b/include/linux/args.h index 8ff60a54eb7d..2e8e65d975c7 100644 --- a/include/linux/args.h +++ b/include/linux/args.h @@ -17,9 +17,9 @@ * that as _n. */ -/* This counts to 12. Any more, it will return 13th argument. */ -#define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n -#define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) +/* This counts to 15. Any more, it will return 16th argument. */ +#define __COUNT_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _n, X...) _n +#define COUNT_ARGS(X...) __COUNT_ARGS(, ##X, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) /* Concatenate two parameters, but allow them to be expanded beforehand. */ #define __CONCAT(a, b) a ## b diff --git a/include/linux/lsm_count.h b/include/linux/lsm_count.h new file mode 100644 index 000000000000..16eb49761b25 --- /dev/null +++ b/include/linux/lsm_count.h @@ -0,0 +1,135 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * Copyright (C) 2023 Google LLC. + */ + +#ifndef __LINUX_LSM_COUNT_H +#define __LINUX_LSM_COUNT_H + +#include + +#ifdef CONFIG_SECURITY + +/* + * Macros to count the number of LSMs enabled in the kernel at compile time. + */ + +/* + * Capabilities is enabled when CONFIG_SECURITY is enabled. + */ +#if IS_ENABLED(CONFIG_SECURITY) +#define CAPABILITIES_ENABLED 1, +#else +#define CAPABILITIES_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_SELINUX) +#define SELINUX_ENABLED 1, +#else +#define SELINUX_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_SMACK) +#define SMACK_ENABLED 1, +#else +#define SMACK_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_APPARMOR) +#define APPARMOR_ENABLED 1, +#else +#define APPARMOR_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_TOMOYO) +#define TOMOYO_ENABLED 1, +#else +#define TOMOYO_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_YAMA) +#define YAMA_ENABLED 1, +#else +#define YAMA_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_LOADPIN) +#define LOADPIN_ENABLED 1, +#else +#define LOADPIN_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_LOCKDOWN_LSM) +#define LOCKDOWN_ENABLED 1, +#else +#define LOCKDOWN_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_SAFESETID) +#define SAFESETID_ENABLED 1, +#else +#define SAFESETID_ENABLED +#endif + +#if IS_ENABLED(CONFIG_BPF_LSM) +#define BPF_LSM_ENABLED 1, +#else +#define BPF_LSM_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_LANDLOCK) +#define LANDLOCK_ENABLED 1, +#else +#define LANDLOCK_ENABLED +#endif + +#if IS_ENABLED(CONFIG_IMA) +#define IMA_ENABLED 1, +#else +#define IMA_ENABLED +#endif + +#if IS_ENABLED(CONFIG_EVM) +#define EVM_ENABLED 1, +#else +#define EVM_ENABLED +#endif + +#if IS_ENABLED(CONFIG_SECURITY_IPE) +#define IPE_ENABLED 1, +#else +#define IPE_ENABLED +#endif + +/* + * There is a trailing comma that we need to be accounted for. This is done by + * using a skipped argument in __COUNT_LSMS + */ +#define __COUNT_LSMS(skipped_arg, args...) COUNT_ARGS(args...) +#define COUNT_LSMS(args...) __COUNT_LSMS(args) + +#define MAX_LSM_COUNT \ + COUNT_LSMS( \ + CAPABILITIES_ENABLED \ + SELINUX_ENABLED \ + SMACK_ENABLED \ + APPARMOR_ENABLED \ + TOMOYO_ENABLED \ + YAMA_ENABLED \ + LOADPIN_ENABLED \ + LOCKDOWN_ENABLED \ + SAFESETID_ENABLED \ + BPF_LSM_ENABLED \ + LANDLOCK_ENABLED \ + IMA_ENABLED \ + EVM_ENABLED \ + IPE_ENABLED) + +#else + +#define MAX_LSM_COUNT 0 + +#endif /* CONFIG_SECURITY */ + +#endif /* __LINUX_LSM_COUNT_H */ -- cgit v1.2.3