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1/*
2 * This is <linux/capability.h>
3 *
4 * Andrew G. Morgan <morgan@kernel.org>
5 * Alexander Kjeldaas <astor@guardian.no>
6 * with help from Aleph1, Roland Buresund and Andrew Main.
7 *
8 * See here for the libcap library ("POSIX draft" compliance):
9 *
10 * ftp://www.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.6/
11 */
12#ifndef _LINUX_CAPABILITY_H
13#define _LINUX_CAPABILITY_H
14
15#include <uapi/linux/capability.h>
16
17
18#define _KERNEL_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_3
19#define _KERNEL_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3
20
21extern int file_caps_enabled;
22
23typedef struct kernel_cap_struct {
24 __u32 cap[_KERNEL_CAPABILITY_U32S];
25} kernel_cap_t;
26
27/* exact same as vfs_cap_data but in cpu endian and always filled completely */
28struct cpu_vfs_cap_data {
29 __u32 magic_etc;
30 kernel_cap_t permitted;
31 kernel_cap_t inheritable;
32};
33
34#define _USER_CAP_HEADER_SIZE (sizeof(struct __user_cap_header_struct))
35#define _KERNEL_CAP_T_SIZE (sizeof(kernel_cap_t))
36
37
38struct file;
39struct inode;
40struct dentry;
41struct user_namespace;
42
43extern const kernel_cap_t __cap_empty_set;
44extern const kernel_cap_t __cap_init_eff_set;
45
46/*
47 * Internal kernel functions only
48 */
49
50#define CAP_FOR_EACH_U32(__capi) \
51 for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi)
52
53/*
54 * CAP_FS_MASK and CAP_NFSD_MASKS:
55 *
56 * The fs mask is all the privileges that fsuid==0 historically meant.
57 * At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE.
58 *
59 * It has never meant setting security.* and trusted.* xattrs.
60 *
61 * We could also define fsmask as follows:
62 * 1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions
63 * 2. The security.* and trusted.* xattrs are fs-related MAC permissions
64 */
65
66# define CAP_FS_MASK_B0 (CAP_TO_MASK(CAP_CHOWN) \
67 | CAP_TO_MASK(CAP_MKNOD) \
68 | CAP_TO_MASK(CAP_DAC_OVERRIDE) \
69 | CAP_TO_MASK(CAP_DAC_READ_SEARCH) \
70 | CAP_TO_MASK(CAP_FOWNER) \
71 | CAP_TO_MASK(CAP_FSETID))
72
73# define CAP_FS_MASK_B1 (CAP_TO_MASK(CAP_MAC_OVERRIDE))
74
75#if _KERNEL_CAPABILITY_U32S != 2
76# error Fix up hand-coded capability macro initializers
77#else /* HAND-CODED capability initializers */
78
79#define CAP_LAST_U32 ((_KERNEL_CAPABILITY_U32S) - 1)
80#define CAP_LAST_U32_VALID_MASK (CAP_TO_MASK(CAP_LAST_CAP + 1) -1)
81
82# define CAP_EMPTY_SET ((kernel_cap_t){{ 0, 0 }})
83# define CAP_FULL_SET ((kernel_cap_t){{ ~0, CAP_LAST_U32_VALID_MASK }})
84# define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
85 | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \
86 CAP_FS_MASK_B1 } })
87# define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
88 | CAP_TO_MASK(CAP_SYS_RESOURCE), \
89 CAP_FS_MASK_B1 } })
90
91#endif /* _KERNEL_CAPABILITY_U32S != 2 */
92
93# define cap_clear(c) do { (c) = __cap_empty_set; } while (0)
94
95#define cap_raise(c, flag) ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag))
96#define cap_lower(c, flag) ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag))
97#define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag))
98
99#define CAP_BOP_ALL(c, a, b, OP) \
100do { \
101 unsigned __capi; \
102 CAP_FOR_EACH_U32(__capi) { \
103 c.cap[__capi] = a.cap[__capi] OP b.cap[__capi]; \
104 } \
105} while (0)
106
107#define CAP_UOP_ALL(c, a, OP) \
108do { \
109 unsigned __capi; \
110 CAP_FOR_EACH_U32(__capi) { \
111 c.cap[__capi] = OP a.cap[__capi]; \
112 } \
113} while (0)
114
115static inline kernel_cap_t cap_combine(const kernel_cap_t a,
116 const kernel_cap_t b)
117{
118 kernel_cap_t dest;
119 CAP_BOP_ALL(dest, a, b, |);
120 return dest;
121}
122
123static inline kernel_cap_t cap_intersect(const kernel_cap_t a,
124 const kernel_cap_t b)
125{
126 kernel_cap_t dest;
127 CAP_BOP_ALL(dest, a, b, &);
128 return dest;
129}
130
131static inline kernel_cap_t cap_drop(const kernel_cap_t a,
132 const kernel_cap_t drop)
133{
134 kernel_cap_t dest;
135 CAP_BOP_ALL(dest, a, drop, &~);
136 return dest;
137}
138
139static inline kernel_cap_t cap_invert(const kernel_cap_t c)
140{
141 kernel_cap_t dest;
142 CAP_UOP_ALL(dest, c, ~);
143 return dest;
144}
145
146static inline bool cap_isclear(const kernel_cap_t a)
147{
148 unsigned __capi;
149 CAP_FOR_EACH_U32(__capi) {
150 if (a.cap[__capi] != 0)
151 return false;
152 }
153 return true;
154}
155
156/*
157 * Check if "a" is a subset of "set".
158 * return true if ALL of the capabilities in "a" are also in "set"
159 * cap_issubset(0101, 1111) will return true
160 * return false if ANY of the capabilities in "a" are not in "set"
161 * cap_issubset(1111, 0101) will return false
162 */
163static inline bool cap_issubset(const kernel_cap_t a, const kernel_cap_t set)
164{
165 kernel_cap_t dest;
166 dest = cap_drop(a, set);
167 return cap_isclear(dest);
168}
169
170/* Used to decide between falling back on the old suser() or fsuser(). */
171
172static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a)
173{
174 const kernel_cap_t __cap_fs_set = CAP_FS_SET;
175 return cap_drop(a, __cap_fs_set);
176}
177
178static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a,
179 const kernel_cap_t permitted)
180{
181 const kernel_cap_t __cap_fs_set = CAP_FS_SET;
182 return cap_combine(a,
183 cap_intersect(permitted, __cap_fs_set));
184}
185
186static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a)
187{
188 const kernel_cap_t __cap_fs_set = CAP_NFSD_SET;
189 return cap_drop(a, __cap_fs_set);
190}
191
192static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
193 const kernel_cap_t permitted)
194{
195 const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET;
196 return cap_combine(a,
197 cap_intersect(permitted, __cap_nfsd_set));
198}
199
200#ifdef CONFIG_MULTIUSER
201extern bool has_capability(struct task_struct *t, int cap);
202extern bool has_ns_capability(struct task_struct *t,
203 struct user_namespace *ns, int cap);
204extern bool has_capability_noaudit(struct task_struct *t, int cap);
205extern bool has_ns_capability_noaudit(struct task_struct *t,
206 struct user_namespace *ns, int cap);
207extern bool capable(int cap);
208extern bool ns_capable(struct user_namespace *ns, int cap);
209#else
210static inline bool has_capability(struct task_struct *t, int cap)
211{
212 return true;
213}
214static inline bool has_ns_capability(struct task_struct *t,
215 struct user_namespace *ns, int cap)
216{
217 return true;
218}
219static inline bool has_capability_noaudit(struct task_struct *t, int cap)
220{
221 return true;
222}
223static inline bool has_ns_capability_noaudit(struct task_struct *t,
224 struct user_namespace *ns, int cap)
225{
226 return true;
227}
228static inline bool capable(int cap)
229{
230 return true;
231}
232static inline bool ns_capable(struct user_namespace *ns, int cap)
233{
234 return true;
235}
236#endif /* CONFIG_MULTIUSER */
237extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap);
238extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
239
240/* audit system wants to get cap info from files as well */
241extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
242
243#endif /* !_LINUX_CAPABILITY_H */