1 /* SPDX-License-Identifier: GPL-2.0-only */ 1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /* 2 /*
3 * Landlock LSM - Filesystem management and ho 3 * Landlock LSM - Filesystem management and hooks
4 * 4 *
5 * Copyright © 2017-2020 Mickaël Salaün <mi 5 * Copyright © 2017-2020 Mickaël Salaün <mic@digikod.net>
6 * Copyright © 2018-2020 ANSSI 6 * Copyright © 2018-2020 ANSSI
7 */ 7 */
8 8
9 #ifndef _SECURITY_LANDLOCK_FS_H 9 #ifndef _SECURITY_LANDLOCK_FS_H
10 #define _SECURITY_LANDLOCK_FS_H 10 #define _SECURITY_LANDLOCK_FS_H
11 11
12 #include <linux/fs.h> 12 #include <linux/fs.h>
13 #include <linux/init.h> 13 #include <linux/init.h>
14 #include <linux/rcupdate.h> 14 #include <linux/rcupdate.h>
15 15
16 #include "ruleset.h" 16 #include "ruleset.h"
17 #include "setup.h" 17 #include "setup.h"
18 18
19 /** 19 /**
20 * struct landlock_inode_security - Inode secu 20 * struct landlock_inode_security - Inode security blob
21 * 21 *
22 * Enable to reference a &struct landlock_obje 22 * Enable to reference a &struct landlock_object tied to an inode (i.e.
23 * underlying object). 23 * underlying object).
24 */ 24 */
25 struct landlock_inode_security { 25 struct landlock_inode_security {
26 /** 26 /**
27 * @object: Weak pointer to an allocat 27 * @object: Weak pointer to an allocated object. All assignments of a
28 * new object are protected by the und 28 * new object are protected by the underlying inode->i_lock. However,
29 * atomically disassociating @object f 29 * atomically disassociating @object from the inode is only protected
30 * by @object->lock, from the time @ob 30 * by @object->lock, from the time @object's usage refcount drops to
31 * zero to the time this pointer is nu 31 * zero to the time this pointer is nulled out (cf. release_inode() and
32 * hook_sb_delete()). Indeed, such di 32 * hook_sb_delete()). Indeed, such disassociation doesn't require
33 * inode->i_lock thanks to the careful 33 * inode->i_lock thanks to the careful rcu_access_pointer() check
34 * performed by get_inode_object(). 34 * performed by get_inode_object().
35 */ 35 */
36 struct landlock_object __rcu *object; 36 struct landlock_object __rcu *object;
37 }; 37 };
38 38
39 /** 39 /**
40 * struct landlock_file_security - File securi 40 * struct landlock_file_security - File security blob
41 * 41 *
42 * This information is populated when opening 42 * This information is populated when opening a file in hook_file_open, and
43 * tracks the relevant Landlock access rights 43 * tracks the relevant Landlock access rights that were available at the time
44 * of opening the file. Other LSM hooks use th 44 * of opening the file. Other LSM hooks use these rights in order to authorize
45 * operations on already opened files. 45 * operations on already opened files.
46 */ 46 */
47 struct landlock_file_security { 47 struct landlock_file_security {
48 /** 48 /**
49 * @allowed_access: Access rights that 49 * @allowed_access: Access rights that were available at the time of
50 * opening the file. This is not neces 50 * opening the file. This is not necessarily the full set of access
51 * rights available at that time, but 51 * rights available at that time, but it's the necessary subset as
52 * needed to authorize later operation 52 * needed to authorize later operations on the open file.
53 */ 53 */
54 access_mask_t allowed_access; 54 access_mask_t allowed_access;
55 /** 55 /**
56 * @fown_domain: Domain of the task th 56 * @fown_domain: Domain of the task that set the PID that may receive a
57 * signal e.g., SIGURG when writing MS 57 * signal e.g., SIGURG when writing MSG_OOB to the related socket.
58 * This pointer is protected by the re 58 * This pointer is protected by the related file->f_owner->lock, as for
59 * fown_struct's members: pid, uid, an 59 * fown_struct's members: pid, uid, and euid.
60 */ 60 */
61 struct landlock_ruleset *fown_domain; 61 struct landlock_ruleset *fown_domain;
62 }; 62 };
63 63
64 /** 64 /**
65 * struct landlock_superblock_security - Super 65 * struct landlock_superblock_security - Superblock security blob
66 * 66 *
67 * Enable hook_sb_delete() to wait for concurr 67 * Enable hook_sb_delete() to wait for concurrent calls to release_inode().
68 */ 68 */
69 struct landlock_superblock_security { 69 struct landlock_superblock_security {
70 /** 70 /**
71 * @inode_refs: Number of pending inod 71 * @inode_refs: Number of pending inodes (from this superblock) that
72 * are being released by release_inode 72 * are being released by release_inode().
73 * Cf. struct super_block->s_fsnotify_ 73 * Cf. struct super_block->s_fsnotify_inode_refs .
74 */ 74 */
75 atomic_long_t inode_refs; 75 atomic_long_t inode_refs;
76 }; 76 };
77 77
78 static inline struct landlock_file_security * 78 static inline struct landlock_file_security *
79 landlock_file(const struct file *const file) 79 landlock_file(const struct file *const file)
80 { 80 {
81 return file->f_security + landlock_blo 81 return file->f_security + landlock_blob_sizes.lbs_file;
82 } 82 }
83 83
84 static inline struct landlock_inode_security * 84 static inline struct landlock_inode_security *
85 landlock_inode(const struct inode *const inode 85 landlock_inode(const struct inode *const inode)
86 { 86 {
87 return inode->i_security + landlock_bl 87 return inode->i_security + landlock_blob_sizes.lbs_inode;
88 } 88 }
89 89
90 static inline struct landlock_superblock_secur 90 static inline struct landlock_superblock_security *
91 landlock_superblock(const struct super_block * 91 landlock_superblock(const struct super_block *const superblock)
92 { 92 {
93 return superblock->s_security + landlo 93 return superblock->s_security + landlock_blob_sizes.lbs_superblock;
94 } 94 }
95 95
96 __init void landlock_add_fs_hooks(void); 96 __init void landlock_add_fs_hooks(void);
97 97
98 int landlock_append_fs_rule(struct landlock_ru 98 int landlock_append_fs_rule(struct landlock_ruleset *const ruleset,
99 const struct path 99 const struct path *const path,
100 access_mask_t acce 100 access_mask_t access_hierarchy);
101 101
102 #endif /* _SECURITY_LANDLOCK_FS_H */ 102 #endif /* _SECURITY_LANDLOCK_FS_H */
103 103
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.