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 task_struct;
42 struct user_namespace;
43
44 extern const kernel_cap_t __cap_empty_set;
45 extern const kernel_cap_t __cap_init_eff_set;
46
47 /*
48 * Internal kernel functions only
49 */
50
51 #define CAP_FOR_EACH_U32(__capi) \
52 for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi)
53
54 /*
55 * CAP_FS_MASK and CAP_NFSD_MASKS:
56 *
57 * The fs mask is all the privileges that fsuid==0 historically meant.
58 * At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE.
59 *
60 * It has never meant setting security.* and trusted.* xattrs.
61 *
62 * We could also define fsmask as follows:
63 * 1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions
64 * 2. The security.* and trusted.* xattrs are fs-related MAC permissions
65 */
66
67 # define CAP_FS_MASK_B0 (CAP_TO_MASK(CAP_CHOWN) \
68 | CAP_TO_MASK(CAP_MKNOD) \
69 | CAP_TO_MASK(CAP_DAC_OVERRIDE) \
70 | CAP_TO_MASK(CAP_DAC_READ_SEARCH) \
71 | CAP_TO_MASK(CAP_FOWNER) \
72 | CAP_TO_MASK(CAP_FSETID))
73
74 # define CAP_FS_MASK_B1 (CAP_TO_MASK(CAP_MAC_OVERRIDE))
75
76 #if _KERNEL_CAPABILITY_U32S != 2
77 # error Fix up hand-coded capability macro initializers
78 #else /* HAND-CODED capability initializers */
79
80 #define CAP_LAST_U32 ((_KERNEL_CAPABILITY_U32S) - 1)
81 #define CAP_LAST_U32_VALID_MASK (CAP_TO_MASK(CAP_LAST_CAP + 1) -1)
82
83 # define CAP_EMPTY_SET ((kernel_cap_t){{ 0, 0 }})
84 # define CAP_FULL_SET ((kernel_cap_t){{ ~0, CAP_LAST_U32_VALID_MASK }})
85 # define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
86 | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \
87 CAP_FS_MASK_B1 } })
88 # define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
89 | CAP_TO_MASK(CAP_SYS_RESOURCE), \
90 CAP_FS_MASK_B1 } })
91
92 #endif /* _KERNEL_CAPABILITY_U32S != 2 */
93
94 # define cap_clear(c) do { (c) = __cap_empty_set; } while (0)
95
96 #define cap_raise(c, flag) ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag))
97 #define cap_lower(c, flag) ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag))
98 #define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag))
99
100 #define CAP_BOP_ALL(c, a, b, OP) \
101 do { \
102 unsigned __capi; \
103 CAP_FOR_EACH_U32(__capi) { \
104 c.cap[__capi] = a.cap[__capi] OP b.cap[__capi]; \
105 } \
106 } while (0)
107
108 #define CAP_UOP_ALL(c, a, OP) \
109 do { \
110 unsigned __capi; \
111 CAP_FOR_EACH_U32(__capi) { \
112 c.cap[__capi] = OP a.cap[__capi]; \
113 } \
114 } while (0)
115
cap_combine(const kernel_cap_t a,const kernel_cap_t b)116 static inline kernel_cap_t cap_combine(const kernel_cap_t a,
117 const kernel_cap_t b)
118 {
119 kernel_cap_t dest;
120 CAP_BOP_ALL(dest, a, b, |);
121 return dest;
122 }
123
cap_intersect(const kernel_cap_t a,const kernel_cap_t b)124 static inline kernel_cap_t cap_intersect(const kernel_cap_t a,
125 const kernel_cap_t b)
126 {
127 kernel_cap_t dest;
128 CAP_BOP_ALL(dest, a, b, &);
129 return dest;
130 }
131
cap_drop(const kernel_cap_t a,const kernel_cap_t drop)132 static inline kernel_cap_t cap_drop(const kernel_cap_t a,
133 const kernel_cap_t drop)
134 {
135 kernel_cap_t dest;
136 CAP_BOP_ALL(dest, a, drop, &~);
137 return dest;
138 }
139
cap_invert(const kernel_cap_t c)140 static inline kernel_cap_t cap_invert(const kernel_cap_t c)
141 {
142 kernel_cap_t dest;
143 CAP_UOP_ALL(dest, c, ~);
144 return dest;
145 }
146
cap_isclear(const kernel_cap_t a)147 static inline bool cap_isclear(const kernel_cap_t a)
148 {
149 unsigned __capi;
150 CAP_FOR_EACH_U32(__capi) {
151 if (a.cap[__capi] != 0)
152 return false;
153 }
154 return true;
155 }
156
157 /*
158 * Check if "a" is a subset of "set".
159 * return true if ALL of the capabilities in "a" are also in "set"
160 * cap_issubset(0101, 1111) will return true
161 * return false if ANY of the capabilities in "a" are not in "set"
162 * cap_issubset(1111, 0101) will return false
163 */
cap_issubset(const kernel_cap_t a,const kernel_cap_t set)164 static inline bool cap_issubset(const kernel_cap_t a, const kernel_cap_t set)
165 {
166 kernel_cap_t dest;
167 dest = cap_drop(a, set);
168 return cap_isclear(dest);
169 }
170
171 /* Used to decide between falling back on the old suser() or fsuser(). */
172
cap_drop_fs_set(const kernel_cap_t a)173 static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a)
174 {
175 const kernel_cap_t __cap_fs_set = CAP_FS_SET;
176 return cap_drop(a, __cap_fs_set);
177 }
178
cap_raise_fs_set(const kernel_cap_t a,const kernel_cap_t permitted)179 static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a,
180 const kernel_cap_t permitted)
181 {
182 const kernel_cap_t __cap_fs_set = CAP_FS_SET;
183 return cap_combine(a,
184 cap_intersect(permitted, __cap_fs_set));
185 }
186
cap_drop_nfsd_set(const kernel_cap_t a)187 static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a)
188 {
189 const kernel_cap_t __cap_fs_set = CAP_NFSD_SET;
190 return cap_drop(a, __cap_fs_set);
191 }
192
cap_raise_nfsd_set(const kernel_cap_t a,const kernel_cap_t permitted)193 static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
194 const kernel_cap_t permitted)
195 {
196 const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET;
197 return cap_combine(a,
198 cap_intersect(permitted, __cap_nfsd_set));
199 }
200
201 #ifdef CONFIG_MULTIUSER
202 extern bool has_capability(struct task_struct *t, int cap);
203 extern bool has_ns_capability(struct task_struct *t,
204 struct user_namespace *ns, int cap);
205 extern bool has_capability_noaudit(struct task_struct *t, int cap);
206 extern bool has_ns_capability_noaudit(struct task_struct *t,
207 struct user_namespace *ns, int cap);
208 extern bool capable(int cap);
209 extern bool ns_capable(struct user_namespace *ns, int cap);
210 extern bool ns_capable_noaudit(struct user_namespace *ns, int cap);
211 #else
has_capability(struct task_struct * t,int cap)212 static inline bool has_capability(struct task_struct *t, int cap)
213 {
214 return true;
215 }
has_ns_capability(struct task_struct * t,struct user_namespace * ns,int cap)216 static inline bool has_ns_capability(struct task_struct *t,
217 struct user_namespace *ns, int cap)
218 {
219 return true;
220 }
has_capability_noaudit(struct task_struct * t,int cap)221 static inline bool has_capability_noaudit(struct task_struct *t, int cap)
222 {
223 return true;
224 }
has_ns_capability_noaudit(struct task_struct * t,struct user_namespace * ns,int cap)225 static inline bool has_ns_capability_noaudit(struct task_struct *t,
226 struct user_namespace *ns, int cap)
227 {
228 return true;
229 }
capable(int cap)230 static inline bool capable(int cap)
231 {
232 return true;
233 }
ns_capable(struct user_namespace * ns,int cap)234 static inline bool ns_capable(struct user_namespace *ns, int cap)
235 {
236 return true;
237 }
ns_capable_noaudit(struct user_namespace * ns,int cap)238 static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap)
239 {
240 return true;
241 }
242 #endif /* CONFIG_MULTIUSER */
243 extern bool privileged_wrt_inode_uidgid(struct user_namespace *ns, const struct inode *inode);
244 extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap);
245 extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
246 extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns);
247
248 /* audit system wants to get cap info from files as well */
249 extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
250
251 #endif /* !_LINUX_CAPABILITY_H */
252