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
21 extern int file_caps_enabled;
22
23 typedef 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 */
28 struct 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
38 struct file;
39 struct inode;
40 struct dentry;
41 struct user_namespace;
42
43 struct user_namespace *current_user_ns(void);
44
45 extern const kernel_cap_t __cap_empty_set;
46 extern 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) \
99 do { \
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) \
107 do { \
108 unsigned __capi; \
109 CAP_FOR_EACH_U32(__capi) { \
110 c.cap[__capi] = OP a.cap[__capi]; \
111 } \
112 } while (0)
113
cap_combine(const kernel_cap_t a,const kernel_cap_t b)114 static 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
cap_intersect(const kernel_cap_t a,const kernel_cap_t b)122 static 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
cap_drop(const kernel_cap_t a,const kernel_cap_t drop)130 static 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
cap_invert(const kernel_cap_t c)138 static 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
cap_isclear(const kernel_cap_t a)145 static 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 */
cap_issubset(const kernel_cap_t a,const kernel_cap_t set)162 static 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
cap_is_fs_cap(int cap)171 static 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
cap_drop_fs_set(const kernel_cap_t a)177 static 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
cap_raise_fs_set(const kernel_cap_t a,const kernel_cap_t permitted)183 static 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
cap_drop_nfsd_set(const kernel_cap_t a)191 static 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
cap_raise_nfsd_set(const kernel_cap_t a,const kernel_cap_t permitted)197 static 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
205 extern bool has_capability(struct task_struct *t, int cap);
206 extern bool has_ns_capability(struct task_struct *t,
207 struct user_namespace *ns, int cap);
208 extern bool has_capability_noaudit(struct task_struct *t, int cap);
209 extern bool has_ns_capability_noaudit(struct task_struct *t,
210 struct user_namespace *ns, int cap);
211 extern bool capable(int cap);
212 extern bool ns_capable(struct user_namespace *ns, int cap);
213 extern bool nsown_capable(int cap);
214 extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap);
215 extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
216
217 /* audit system wants to get cap info from files as well */
218 extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
219
220 #endif /* !_LINUX_CAPABILITY_H */
221