From patchwork Thu May 9 20:14:18 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: KP Singh X-Patchwork-Id: 13660358 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AF3467F46C; Thu, 9 May 2024 20:14:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715285673; cv=none; b=h6TG15O6f1o1leP7NEPKuRE2DaEVfK8zln5lEjTkQk6IGMX0jM1x14Iv9o2UwCnkNbC3zvu0H4k3a8l8wG3JMyPJE76HCSAA4qrydQ39dcQkWZEtz4Eih3iK2qVKMMwTg0NUbwM9iWWeaG46fbRts0/7XmfYBNhTuHBgB38+GXs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715285673; c=relaxed/simple; bh=p8BqKBABunGKsj/z1GDh6EQ4KdTKbPxJbtzfJJwKl+M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WtMth7XCHiy//rbTswKMsRzrKS3Vl/vQY73dQB+pFMYB6M5EpOJYKaaUVUjqAO/0EFHrX445FYIlRM0aFi4gCNXTAkCASQkPKB3cXHduun3g+L+g6QeEdQ7PkiUbP0/YfeDnIe2VMtSMlzhatBSKOBfqpOAVmwpNGXr7DPpkDX4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GvqScUm8; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GvqScUm8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DD37DC116B1; Thu, 9 May 2024 20:14:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1715285673; bh=p8BqKBABunGKsj/z1GDh6EQ4KdTKbPxJbtzfJJwKl+M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GvqScUm8P00Mj5e7oWHyBwANaETMc5F9YOP3ztOTO9l7rSTGwqQNxCw+Rru+F/h58 dvgxeXqsirT0HeE1AHswkOsorX6fy4RBgiYdAtaqth8taOQwxS4dI0Spl7Fsm6wINw JGoHgwD3En2127mZsNcLG+FRWyxzaDTihDq3RT33zbeu35b3aeX4aaTr5X5+rUpiMS 70U2kRPE1X14tNoEMy+Tz7Xjci6TX2vo3yzPGJtNxCmgvsX6P3JEmBBcE+qTwHK9A+ rX1hbLRWbIdmpQkGwKJXCuaG2g7vp9M2SuNftp7M0tNN51DNepT25pGRVi+aPnal5W hH97OoEcmZD7w== From: KP Singh To: linux-security-module@vger.kernel.org, bpf@vger.kernel.org Cc: ast@kernel.org, paul@paul-moore.com, casey@schaufler-ca.com, andrii@kernel.org, keescook@chromium.org, daniel@iogearbox.net, renauld@google.com, revest@chromium.org, song@kernel.org, Kui-Feng Lee , KP Singh Subject: [PATCH v11 2/5] security: Count the LSMs enabled at compile time Date: Thu, 9 May 2024 22:14:18 +0200 Message-ID: <20240509201421.905965-3-kpsingh@kernel.org> X-Mailer: git-send-email 2.45.0.118.g7fe29c98d7-goog In-Reply-To: <20240509201421.905965-1-kpsingh@kernel.org> References: <20240509201421.905965-1-kpsingh@kernel.org> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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. Suggested-by: Kui-Feng Lee Suggested-by: Andrii Nakryiko Acked-by: Song Liu Acked-by: Andrii Nakryiko Reviewed-by: Kees Cook Signed-off-by: KP Singh Reviewed-by: Casey Schaufler --- include/linux/args.h | 6 +- include/linux/lsm_count.h | 128 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 131 insertions(+), 3 deletions(-) create mode 100644 include/linux/lsm_count.h 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..73c7cc81349b --- /dev/null +++ b/include/linux/lsm_count.h @@ -0,0 +1,128 @@ +/* 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 + +/* + * 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) + +#else + +#define MAX_LSM_COUNT 0 + +#endif /* CONFIG_SECURITY */ + +#endif /* __LINUX_LSM_COUNT_H */