Commit f3b8788c authored by Casey Schaufler's avatar Casey Schaufler Committed by Paul Moore
Browse files

LSM: Identify modules by more than name 



Create a struct lsm_id to contain identifying information about Linux
Security Modules (LSMs). At inception this contains the name of the
module and an identifier associated with the security module.  Change
the security_add_hooks() interface to use this structure.  Change the
individual modules to maintain their own struct lsm_id and pass it to
security_add_hooks().

The values are for LSM identifiers are defined in a new UAPI
header file linux/lsm.h. Each existing LSM has been updated to
include it's LSMID in the lsm_id.

The LSM ID values are sequential, with the oldest module
LSM_ID_CAPABILITY being the lowest value and the existing modules
numbered in the order they were included in the main line kernel.
This is an arbitrary convention for assigning the values, but
none better presents itself. The value 0 is defined as being invalid.
The values 1-99 are reserved for any special case uses which may
arise in the future. This may include attributes of the LSM
infrastructure itself, possibly related to namespacing or network
attribute management. A special range is identified for such attributes
to help reduce confusion for developers unfamiliar with LSMs.

LSM attribute values are defined for the attributes presented by
modules that are available today. As with the LSM IDs, The value 0
is defined as being invalid. The values 1-99 are reserved for any
special case uses which may arise in the future.

Cc: linux-security-module <linux-security-module@vger.kernel.org>
Signed-off-by: default avatarCasey Schaufler <casey@schaufler-ca.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Reviewed-by: default avatarSerge Hallyn <serge@hallyn.com>
Reviewed-by: default avatarMickael Salaun <mic@digikod.net>
Reviewed-by: default avatarJohn Johansen <john.johansen@canonical.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Nacked-by: default avatarTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
[PM: forward ported beyond v6.6 due merge window changes]
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent b85ea95d

Documentation/userspace-api/index.rst

+1 −0
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@@ -33,6 +33,7 @@ place where this information is gathered. 
   sysfs-platform_profile

   vduse

   futex2

   lsm



.. only::  subproject and html

MAINTAINERS

+1 −0
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@@ -19511,6 +19511,7 @@ L: linux-security-module@vger.kernel.org (suggested Cc:) 
S:	Supported

W:	http://kernsec.org/

T:	git git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm.git

F:	include/uapi/linux/lsm.h

F:	security/

X:	security/selinux/

























include/linux/lsm_hooks.h



+14
−2






























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@@ -42,6 +42,18 @@ struct security_hook_heads {







	#undef LSM_HOOK









} __randomize_layout;



















/**









 * struct lsm_id - Identify a Linux Security Module.









 * @lsm: name of the LSM, must be approved by the LSM maintainers









 * @id: LSM ID number from uapi/linux/lsm.h









 *









 * Contains the information that identifies the LSM.









 */









struct lsm_id {









	const char	*name;









	u64		id;









};



















/*









 * Security module hook list structure.









 * For use with generic list macros for common operations.








@@ -50,7 +62,7 @@ struct security_hook_list {







	struct hlist_node		list;









	struct hlist_head		*head;









	union security_list_options	hook;









	const char			*lsm;









	const struct lsm_id		*lsmid;









} __randomize_layout;



















/*








@@ -104,7 +116,7 @@ extern struct security_hook_heads security_hook_heads;







extern char *lsm_names;



















extern void security_add_hooks(struct security_hook_list *hooks, int count,









				const char *lsm);









			       const struct lsm_id *lsmid);



















#define LSM_FLAG_LEGACY_MAJOR	BIT(0)









#define LSM_FLAG_EXCLUSIVE	BIT(1)
































include/uapi/linux/lsm.h
0 → 100644



+54
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/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */









/*









 * Linux Security Modules (LSM) - User space API









 *









 * Copyright (C) 2022 Casey Schaufler <casey@schaufler-ca.com>









 * Copyright (C) 2022 Intel Corporation









 */



















#ifndef _UAPI_LINUX_LSM_H









#define _UAPI_LINUX_LSM_H



















/*









 * ID tokens to identify Linux Security Modules (LSMs)









 *









 * These token values are used to uniquely identify specific LSMs









 * in the kernel as well as in the kernel's LSM userspace API.









 *









 * A value of zero/0 is considered undefined and should not be used









 * outside the kernel. Values 1-99 are reserved for potential









 * future use.









 */









#define LSM_ID_UNDEF		0









#define LSM_ID_CAPABILITY	100









#define LSM_ID_SELINUX		101









#define LSM_ID_SMACK		102









#define LSM_ID_TOMOYO		103









#define LSM_ID_IMA		104









#define LSM_ID_APPARMOR		105









#define LSM_ID_YAMA		106









#define LSM_ID_LOADPIN		107









#define LSM_ID_SAFESETID	108









#define LSM_ID_LOCKDOWN		109









#define LSM_ID_BPF		110









#define LSM_ID_LANDLOCK		111



















/*









 * LSM_ATTR_XXX definitions identify different LSM attributes









 * which are used in the kernel's LSM userspace API. Support









 * for these attributes vary across the different LSMs. None









 * are required.









 *









 * A value of zero/0 is considered undefined and should not be used









 * outside the kernel. Values 1-99 are reserved for potential









 * future use.









 */









#define LSM_ATTR_UNDEF		0









#define LSM_ATTR_CURRENT	100









#define LSM_ATTR_EXEC		101









#define LSM_ATTR_FSCREATE	102









#define LSM_ATTR_KEYCREATE	103









#define LSM_ATTR_PREV		104









#define LSM_ATTR_SOCKCREATE	105



















#endif /* _UAPI_LINUX_LSM_H */
























security/apparmor/lsm.c



+7
−1






























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@@ -24,6 +24,7 @@







#include <linux/zstd.h>









#include <net/sock.h>









#include <uapi/linux/mount.h>









#include <uapi/linux/lsm.h>



















#include "include/apparmor.h"









#include "include/apparmorfs.h"








@@ -1385,6 +1386,11 @@ struct lsm_blob_sizes apparmor_blob_sizes __ro_after_init = {







	.lbs_task = sizeof(struct aa_task_ctx),









};



















const struct lsm_id apparmor_lsmid = {









	.name = "apparmor",









	.id = LSM_ID_APPARMOR,









};



















static struct security_hook_list apparmor_hooks[] __ro_after_init = {









	LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check),









	LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme),








@@ -2202,7 +2208,7 @@ static int __init apparmor_init(void)







		goto buffers_out;









	}









	security_add_hooks(apparmor_hooks, ARRAY_SIZE(apparmor_hooks),









				"apparmor");









				&apparmor_lsmid);



















	/* Report that AppArmor successfully initialized */









	apparmor_initialized = 1;