1 /*
2 * Linux Security Module interfaces
3 *
4 * Copyright (C) 2001 WireX Communications, Inc <chris@wirex.com>
5 * Copyright (C) 2001 Greg Kroah-Hartman <greg@kroah.com>
6 * Copyright (C) 2001 Networks Associates Technology, Inc <ssmalley@nai.com>
7 * Copyright (C) 2001 James Morris <jmorris@intercode.com.au>
8 * Copyright (C) 2001 Silicon Graphics, Inc. (Trust Technology Group)
9 * Copyright (C) 2015 Intel Corporation.
10 * Copyright (C) 2015 Casey Schaufler <casey@schaufler-ca.com>
11 * Copyright (C) 2016 Mellanox Techonologies
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
17 *
18 * Due to this file being licensed under the GPL there is controversy over
19 * whether this permits you to write a module that #includes this file
20 * without placing your module under the GPL. Please consult a lawyer for
21 * advice before doing this.
22 *
23 */
24
25 #ifndef __LINUX_LSM_HOOKS_H
26 #define __LINUX_LSM_HOOKS_H
27
28 #include <linux/security.h>
29 #include <linux/init.h>
30 #include <linux/rculist.h>
31 #include <linux/xattr.h>
32
33 union security_list_options {
34 #define LSM_HOOK(RET, DEFAULT, NAME, ...) RET (*NAME)(__VA_ARGS__);
35 #include "lsm_hook_defs.h"
36 #undef LSM_HOOK
37 };
38
39 struct security_hook_heads {
40 #define LSM_HOOK(RET, DEFAULT, NAME, ...) struct hlist_head NAME;
41 #include "lsm_hook_defs.h"
42 #undef LSM_HOOK
43 } __randomize_layout;
44
45 /*
46 * Security module hook list structure.
47 * For use with generic list macros for common operations.
48 */
49 struct security_hook_list {
50 struct hlist_node list;
51 struct hlist_head *head;
52 union security_list_options hook;
53 const char *lsm;
54 } __randomize_layout;
55
56 /*
57 * Security blob size or offset data.
58 */
59 struct lsm_blob_sizes {
60 int lbs_cred;
61 int lbs_file;
62 int lbs_inode;
63 int lbs_superblock;
64 int lbs_ipc;
65 int lbs_msg_msg;
66 int lbs_task;
67 int lbs_xattr_count; /* number of xattr slots in new_xattrs array */
68 };
69
70 /**
71 * lsm_get_xattr_slot - Return the next available slot and increment the index
72 * @xattrs: array storing LSM-provided xattrs
73 * @xattr_count: number of already stored xattrs (updated)
74 *
75 * Retrieve the first available slot in the @xattrs array to fill with an xattr,
76 * and increment @xattr_count.
77 *
78 * Return: The slot to fill in @xattrs if non-NULL, NULL otherwise.
79 */
lsm_get_xattr_slot(struct xattr * xattrs,int * xattr_count)80 static inline struct xattr *lsm_get_xattr_slot(struct xattr *xattrs,
81 int *xattr_count)
82 {
83 if (unlikely(!xattrs))
84 return NULL;
85 return &xattrs[(*xattr_count)++];
86 }
87
88 /*
89 * LSM_RET_VOID is used as the default value in LSM_HOOK definitions for void
90 * LSM hooks (in include/linux/lsm_hook_defs.h).
91 */
92 #define LSM_RET_VOID ((void) 0)
93
94 /*
95 * Initializing a security_hook_list structure takes
96 * up a lot of space in a source file. This macro takes
97 * care of the common case and reduces the amount of
98 * text involved.
99 */
100 #define LSM_HOOK_INIT(HEAD, HOOK) \
101 { .head = &security_hook_heads.HEAD, .hook = { .HEAD = HOOK } }
102
103 extern struct security_hook_heads security_hook_heads;
104 extern char *lsm_names;
105
106 extern void security_add_hooks(struct security_hook_list *hooks, int count,
107 const char *lsm);
108
109 #define LSM_FLAG_LEGACY_MAJOR BIT(0)
110 #define LSM_FLAG_EXCLUSIVE BIT(1)
111
112 enum lsm_order {
113 LSM_ORDER_FIRST = -1, /* This is only for capabilities. */
114 LSM_ORDER_MUTABLE = 0,
115 LSM_ORDER_LAST = 1, /* This is only for integrity. */
116 };
117
118 struct lsm_info {
119 const char *name; /* Required. */
120 enum lsm_order order; /* Optional: default is LSM_ORDER_MUTABLE */
121 unsigned long flags; /* Optional: flags describing LSM */
122 int *enabled; /* Optional: controlled by CONFIG_LSM */
123 int (*init)(void); /* Required. */
124 struct lsm_blob_sizes *blobs; /* Optional: for blob sharing. */
125 };
126
127 extern struct lsm_info __start_lsm_info[], __end_lsm_info[];
128 extern struct lsm_info __start_early_lsm_info[], __end_early_lsm_info[];
129
130 #define DEFINE_LSM(lsm) \
131 static struct lsm_info __lsm_##lsm \
132 __used __section(".lsm_info.init") \
133 __aligned(sizeof(unsigned long))
134
135 #define DEFINE_EARLY_LSM(lsm) \
136 static struct lsm_info __early_lsm_##lsm \
137 __used __section(".early_lsm_info.init") \
138 __aligned(sizeof(unsigned long))
139
140 extern int lsm_inode_alloc(struct inode *inode);
141
142 #endif /* ! __LINUX_LSM_HOOKS_H */
143