Line data    Source code

       1             : /* SPDX-License-Identifier: GPL-2.0-only */
       2             : /*
       3             :  * Landlock LSM - Filesystem management and hooks
       4             :  *
       5             :  * Copyright © 2017-2020 Mickaël Salaün <mic@digikod.net>
       6             :  * Copyright © 2018-2020 ANSSI
       7             :  */
       8             : 
       9             : #ifndef _SECURITY_LANDLOCK_FS_H
      10             : #define _SECURITY_LANDLOCK_FS_H
      11             : 
      12             : #include <linux/fs.h>
      13             : #include <linux/init.h>
      14             : #include <linux/rcupdate.h>
      15             : 
      16             : #include "ruleset.h"
      17             : #include "setup.h"
      18             : 
      19             : /**
      20             :  * struct landlock_inode_security - Inode security blob
      21             :  *
      22             :  * Enable to reference a &struct landlock_object tied to an inode (i.e.
      23             :  * underlying object).
      24             :  */
      25             : struct landlock_inode_security {
      26             :         /**
      27             :          * @object: Weak pointer to an allocated object.  All assignments of a
      28             :          * new object are protected by the underlying inode->i_lock.  However,
      29             :          * atomically disassociating @object from the inode is only protected
      30             :          * by @object->lock, from the time @object's usage refcount drops to
      31             :          * zero to the time this pointer is nulled out (cf. release_inode() and
      32             :          * hook_sb_delete()).  Indeed, such disassociation doesn't require
      33             :          * inode->i_lock thanks to the careful rcu_access_pointer() check
      34             :          * performed by get_inode_object().
      35             :          */
      36             :         struct landlock_object __rcu *object;
      37             : };
      38             : 
      39             : /**
      40             :  * struct landlock_superblock_security - Superblock security blob
      41             :  *
      42             :  * Enable hook_sb_delete() to wait for concurrent calls to release_inode().
      43             :  */
      44             : struct landlock_superblock_security {
      45             :         /**
      46             :          * @inode_refs: Number of pending inodes (from this superblock) that
      47             :          * are being released by release_inode().
      48             :          * Cf. struct super_block->s_fsnotify_inode_refs .
      49             :          */
      50             :         atomic_long_t inode_refs;
      51             : };
      52             : 
      53        7395 : static inline struct landlock_inode_security *landlock_inode(
      54             :                 const struct inode *const inode)
      55             : {
      56        7395 :         return inode->i_security + landlock_blob_sizes.lbs_inode;
      57             : }
      58             : 
      59         113 : static inline struct landlock_superblock_security *landlock_superblock(
      60             :                 const struct super_block *const superblock)
      61             : {
      62         113 :         return superblock->s_security + landlock_blob_sizes.lbs_superblock;
      63             : }
      64             : 
      65             : __init void landlock_add_fs_hooks(void);
      66             : 
      67             : int landlock_append_fs_rule(struct landlock_ruleset *const ruleset,
      68             :                 const struct path *const path, u32 access_hierarchy);
      69             : 
      70             : #endif /* _SECURITY_LANDLOCK_FS_H */