linux/security/landlock/fs.h
Mickaël Salaün 5f2ff33e10
landlock: Define access_mask_t to enforce a consistent access mask size
Create and use the access_mask_t typedef to enforce a consistent access
mask size and uniformly use a 16-bits type.  This will helps transition
to a 32-bits value one day.

Add a build check to make sure all (filesystem) access rights fit in.
This will be extended with a following commit.

Reviewed-by: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20220506161102.525323-2-mic@digikod.net
Cc: stable@vger.kernel.org
Signed-off-by: Mickaël Salaün <mic@digikod.net>
2022-05-23 13:27:55 +02:00

72 lines
2.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Landlock LSM - Filesystem management and hooks
*
* Copyright © 2017-2020 Mickaël Salaün <mic@digikod.net>
* Copyright © 2018-2020 ANSSI
*/
#ifndef _SECURITY_LANDLOCK_FS_H
#define _SECURITY_LANDLOCK_FS_H
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/rcupdate.h>
#include "ruleset.h"
#include "setup.h"
/**
* struct landlock_inode_security - Inode security blob
*
* Enable to reference a &struct landlock_object tied to an inode (i.e.
* underlying object).
*/
struct landlock_inode_security {
/**
* @object: Weak pointer to an allocated object. All assignments of a
* new object are protected by the underlying inode->i_lock. However,
* atomically disassociating @object from the inode is only protected
* by @object->lock, from the time @object's usage refcount drops to
* zero to the time this pointer is nulled out (cf. release_inode() and
* hook_sb_delete()). Indeed, such disassociation doesn't require
* inode->i_lock thanks to the careful rcu_access_pointer() check
* performed by get_inode_object().
*/
struct landlock_object __rcu *object;
};
/**
* struct landlock_superblock_security - Superblock security blob
*
* Enable hook_sb_delete() to wait for concurrent calls to release_inode().
*/
struct landlock_superblock_security {
/**
* @inode_refs: Number of pending inodes (from this superblock) that
* are being released by release_inode().
* Cf. struct super_block->s_fsnotify_inode_refs .
*/
atomic_long_t inode_refs;
};
static inline struct landlock_inode_security *
landlock_inode(const struct inode *const inode)
{
return inode->i_security + landlock_blob_sizes.lbs_inode;
}
static inline struct landlock_superblock_security *
landlock_superblock(const struct super_block *const superblock)
{
return superblock->s_security + landlock_blob_sizes.lbs_superblock;
}
__init void landlock_add_fs_hooks(void);
int landlock_append_fs_rule(struct landlock_ruleset *const ruleset,
const struct path *const path,
access_mask_t access_hierarchy);
#endif /* _SECURITY_LANDLOCK_FS_H */