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 extern const kernel_cap_t __cap_empty_set;
44 extern 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) \
100 do { \
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) \
108 do { \
109 unsigned __capi; \
110 CAP_FOR_EACH_U32(__capi) { \
111 c.cap[__capi] = OP a.cap[__capi]; \
112 } \
113 } while (0)
114
cap_combine(const kernel_cap_t a,const kernel_cap_t b)115 static 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
cap_intersect(const kernel_cap_t a,const kernel_cap_t b)123 static 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
cap_drop(const kernel_cap_t a,const kernel_cap_t drop)131 static 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
cap_invert(const kernel_cap_t c)139 static 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
cap_isclear(const kernel_cap_t a)146 static inline int 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 0;
152 }
153 return 1;
154 }
155
156 /*
157 * Check if "a" is a subset of "set".
158 * return 1 if ALL of the capabilities in "a" are also in "set"
159 * cap_issubset(0101, 1111) will return 1
160 * return 0 if ANY of the capabilities in "a" are not in "set"
161 * cap_issubset(1111, 0101) will return 0
162 */
cap_issubset(const kernel_cap_t a,const kernel_cap_t set)163 static inline int 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
cap_is_fs_cap(int cap)172 static inline int cap_is_fs_cap(int cap)
173 {
174 const kernel_cap_t __cap_fs_set = CAP_FS_SET;
175 return !!(CAP_TO_MASK(cap) & __cap_fs_set.cap[CAP_TO_INDEX(cap)]);
176 }
177
cap_drop_fs_set(const kernel_cap_t a)178 static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a)
179 {
180 const kernel_cap_t __cap_fs_set = CAP_FS_SET;
181 return cap_drop(a, __cap_fs_set);
182 }
183
cap_raise_fs_set(const kernel_cap_t a,const kernel_cap_t permitted)184 static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a,
185 const kernel_cap_t permitted)
186 {
187 const kernel_cap_t __cap_fs_set = CAP_FS_SET;
188 return cap_combine(a,
189 cap_intersect(permitted, __cap_fs_set));
190 }
191
cap_drop_nfsd_set(const kernel_cap_t a)192 static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a)
193 {
194 const kernel_cap_t __cap_fs_set = CAP_NFSD_SET;
195 return cap_drop(a, __cap_fs_set);
196 }
197
cap_raise_nfsd_set(const kernel_cap_t a,const kernel_cap_t permitted)198 static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
199 const kernel_cap_t permitted)
200 {
201 const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET;
202 return cap_combine(a,
203 cap_intersect(permitted, __cap_nfsd_set));
204 }
205
206 extern bool has_capability(struct task_struct *t, int cap);
207 extern bool has_ns_capability(struct task_struct *t,
208 struct user_namespace *ns, int cap);
209 extern bool has_capability_noaudit(struct task_struct *t, int cap);
210 extern bool has_ns_capability_noaudit(struct task_struct *t,
211 struct user_namespace *ns, int cap);
212 extern bool capable(int cap);
213 extern bool ns_capable(struct user_namespace *ns, 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