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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
43struct user_namespace *current_user_ns(void);
44
45extern const kernel_cap_t __cap_empty_set;
46extern const kernel_cap_t __cap_init_eff_set;
47
48/*
49 * Internal kernel functions only
50 */
51
52#define CAP_FOR_EACH_U32(__capi) \
53 for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi)
54
55/*
56 * CAP_FS_MASK and CAP_NFSD_MASKS:
57 *
58 * The fs mask is all the privileges that fsuid==0 historically meant.
59 * At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE.
60 *
61 * It has never meant setting security.* and trusted.* xattrs.
62 *
63 * We could also define fsmask as follows:
64 * 1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions
65 * 2. The security.* and trusted.* xattrs are fs-related MAC permissions
66 */
67
68# define CAP_FS_MASK_B0 (CAP_TO_MASK(CAP_CHOWN) \
69 | CAP_TO_MASK(CAP_MKNOD) \
70 | CAP_TO_MASK(CAP_DAC_OVERRIDE) \
71 | CAP_TO_MASK(CAP_DAC_READ_SEARCH) \
72 | CAP_TO_MASK(CAP_FOWNER) \
73 | CAP_TO_MASK(CAP_FSETID))
74
75# define CAP_FS_MASK_B1 (CAP_TO_MASK(CAP_MAC_OVERRIDE))
76
77#if _KERNEL_CAPABILITY_U32S != 2
78# error Fix up hand-coded capability macro initializers
79#else /* HAND-CODED capability initializers */
80
81# define CAP_EMPTY_SET ((kernel_cap_t){{ 0, 0 }})
82# define CAP_FULL_SET ((kernel_cap_t){{ ~0, ~0 }})
83# define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
84 | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \
85 CAP_FS_MASK_B1 } })
86# define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
87 | CAP_TO_MASK(CAP_SYS_RESOURCE), \
88 CAP_FS_MASK_B1 } })
89
90#endif /* _KERNEL_CAPABILITY_U32S != 2 */
91
92# define cap_clear(c) do { (c) = __cap_empty_set; } while (0)
93
94#define cap_raise(c, flag) ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag))
95#define cap_lower(c, flag) ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag))
96#define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag))
97
98#define CAP_BOP_ALL(c, a, b, OP) \
99do { \
100 unsigned __capi; \
101 CAP_FOR_EACH_U32(__capi) { \
102 c.cap[__capi] = a.cap[__capi] OP b.cap[__capi]; \
103 } \
104} while (0)
105
106#define CAP_UOP_ALL(c, a, OP) \
107do { \
108 unsigned __capi; \
109 CAP_FOR_EACH_U32(__capi) { \
110 c.cap[__capi] = OP a.cap[__capi]; \
111 } \
112} while (0)
113
114static inline kernel_cap_t cap_combine(const kernel_cap_t a,
115 const kernel_cap_t b)
116{
117 kernel_cap_t dest;
118 CAP_BOP_ALL(dest, a, b, |);
119 return dest;
120}
121
122static inline kernel_cap_t cap_intersect(const kernel_cap_t a,
123 const kernel_cap_t b)
124{
125 kernel_cap_t dest;
126 CAP_BOP_ALL(dest, a, b, &);
127 return dest;
128}
129
130static inline kernel_cap_t cap_drop(const kernel_cap_t a,
131 const kernel_cap_t drop)
132{
133 kernel_cap_t dest;
134 CAP_BOP_ALL(dest, a, drop, &~);
135 return dest;
136}
137
138static inline kernel_cap_t cap_invert(const kernel_cap_t c)
139{
140 kernel_cap_t dest;
141 CAP_UOP_ALL(dest, c, ~);
142 return dest;
143}
144
145static inline int cap_isclear(const kernel_cap_t a)
146{
147 unsigned __capi;
148 CAP_FOR_EACH_U32(__capi) {
149 if (a.cap[__capi] != 0)
150 return 0;
151 }
152 return 1;
153}
154
155/*
156 * Check if "a" is a subset of "set".
157 * return 1 if ALL of the capabilities in "a" are also in "set"
158 * cap_issubset(0101, 1111) will return 1
159 * return 0 if ANY of the capabilities in "a" are not in "set"
160 * cap_issubset(1111, 0101) will return 0
161 */
162static inline int cap_issubset(const kernel_cap_t a, const kernel_cap_t set)
163{
164 kernel_cap_t dest;
165 dest = cap_drop(a, set);
166 return cap_isclear(dest);
167}
168
169/* Used to decide between falling back on the old suser() or fsuser(). */
170
171static inline int cap_is_fs_cap(int cap)
172{
173 const kernel_cap_t __cap_fs_set = CAP_FS_SET;
174 return !!(CAP_TO_MASK(cap) & __cap_fs_set.cap[CAP_TO_INDEX(cap)]);
175}
176
177static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a)
178{
179 const kernel_cap_t __cap_fs_set = CAP_FS_SET;
180 return cap_drop(a, __cap_fs_set);
181}
182
183static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a,
184 const kernel_cap_t permitted)
185{
186 const kernel_cap_t __cap_fs_set = CAP_FS_SET;
187 return cap_combine(a,
188 cap_intersect(permitted, __cap_fs_set));
189}
190
191static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a)
192{
193 const kernel_cap_t __cap_fs_set = CAP_NFSD_SET;
194 return cap_drop(a, __cap_fs_set);
195}
196
197static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
198 const kernel_cap_t permitted)
199{
200 const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET;
201 return cap_combine(a,
202 cap_intersect(permitted, __cap_nfsd_set));
203}
204
205extern bool has_capability(struct task_struct *t, int cap);
206extern bool has_ns_capability(struct task_struct *t,
207 struct user_namespace *ns, int cap);
208extern bool has_capability_noaudit(struct task_struct *t, int cap);
209extern bool has_ns_capability_noaudit(struct task_struct *t,
210 struct user_namespace *ns, int cap);
211extern bool capable(int cap);
212extern bool ns_capable(struct user_namespace *ns, int cap);
213extern bool inode_capable(const struct inode *inode, int cap);
214extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
215
216/* audit system wants to get cap info from files as well */
217extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
218
219#endif /* !_LINUX_CAPABILITY_H */