1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * This is <linux/capability.h>
4 *
5 * Andrew G. Morgan <morgan@kernel.org>
6 * Alexander Kjeldaas <astor@guardian.no>
7 * with help from Aleph1, Roland Buresund and Andrew Main.
8 *
9 * See here for the libcap library ("POSIX draft" compliance):
10 *
11 * ftp://www.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.6/
12 */
13 #ifndef _LINUX_CAPABILITY_H
14 #define _LINUX_CAPABILITY_H
15
16 #include <uapi/linux/capability.h>
17 #include <linux/uidgid.h>
18
19 #define _KERNEL_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_3
20 #define _KERNEL_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3
21
22 extern int file_caps_enabled;
23
24 typedef struct kernel_cap_struct {
25 __u32 cap[_KERNEL_CAPABILITY_U32S];
26 } kernel_cap_t;
27
28 /* same as vfs_ns_cap_data but in cpu endian and always filled completely */
29 struct cpu_vfs_cap_data {
30 __u32 magic_etc;
31 kernel_cap_t permitted;
32 kernel_cap_t inheritable;
33 kuid_t rootid;
34 };
35
36 #define _USER_CAP_HEADER_SIZE (sizeof(struct __user_cap_header_struct))
37 #define _KERNEL_CAP_T_SIZE (sizeof(kernel_cap_t))
38
39
40 struct file;
41 struct inode;
42 struct dentry;
43 struct task_struct;
44 struct user_namespace;
45
46 extern const kernel_cap_t __cap_empty_set;
47 extern const kernel_cap_t __cap_init_eff_set;
48
49 /*
50 * Internal kernel functions only
51 */
52
53 #define CAP_FOR_EACH_U32(__capi) \
54 for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi)
55
56 /*
57 * CAP_FS_MASK and CAP_NFSD_MASKS:
58 *
59 * The fs mask is all the privileges that fsuid==0 historically meant.
60 * At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE.
61 *
62 * It has never meant setting security.* and trusted.* xattrs.
63 *
64 * We could also define fsmask as follows:
65 * 1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions
66 * 2. The security.* and trusted.* xattrs are fs-related MAC permissions
67 */
68
69 # define CAP_FS_MASK_B0 (CAP_TO_MASK(CAP_CHOWN) \
70 | CAP_TO_MASK(CAP_MKNOD) \
71 | CAP_TO_MASK(CAP_DAC_OVERRIDE) \
72 | CAP_TO_MASK(CAP_DAC_READ_SEARCH) \
73 | CAP_TO_MASK(CAP_FOWNER) \
74 | CAP_TO_MASK(CAP_FSETID))
75
76 # define CAP_FS_MASK_B1 (CAP_TO_MASK(CAP_MAC_OVERRIDE))
77
78 #if _KERNEL_CAPABILITY_U32S != 2
79 # error Fix up hand-coded capability macro initializers
80 #else /* HAND-CODED capability initializers */
81
82 #define CAP_LAST_U32 ((_KERNEL_CAPABILITY_U32S) - 1)
83 #define CAP_LAST_U32_VALID_MASK (CAP_TO_MASK(CAP_LAST_CAP + 1) -1)
84
85 # define CAP_EMPTY_SET ((kernel_cap_t){{ 0, 0 }})
86 # define CAP_FULL_SET ((kernel_cap_t){{ ~0, CAP_LAST_U32_VALID_MASK }})
87 # define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
88 | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \
89 CAP_FS_MASK_B1 } })
90 # define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
91 | CAP_TO_MASK(CAP_SYS_RESOURCE), \
92 CAP_FS_MASK_B1 } })
93
94 #endif /* _KERNEL_CAPABILITY_U32S != 2 */
95
96 # define cap_clear(c) do { (c) = __cap_empty_set; } while (0)
97
98 #define cap_raise(c, flag) ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag))
99 #define cap_lower(c, flag) ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag))
100 #define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag))
101
102 #define CAP_BOP_ALL(c, a, b, OP) \
103 do { \
104 unsigned __capi; \
105 CAP_FOR_EACH_U32(__capi) { \
106 c.cap[__capi] = a.cap[__capi] OP b.cap[__capi]; \
107 } \
108 } while (0)
109
110 #define CAP_UOP_ALL(c, a, OP) \
111 do { \
112 unsigned __capi; \
113 CAP_FOR_EACH_U32(__capi) { \
114 c.cap[__capi] = OP a.cap[__capi]; \
115 } \
116 } while (0)
117
cap_combine(const kernel_cap_t a,const kernel_cap_t b)118 static inline kernel_cap_t cap_combine(const kernel_cap_t a,
119 const kernel_cap_t b)
120 {
121 kernel_cap_t dest;
122 CAP_BOP_ALL(dest, a, b, |);
123 return dest;
124 }
125
cap_intersect(const kernel_cap_t a,const kernel_cap_t b)126 static inline kernel_cap_t cap_intersect(const kernel_cap_t a,
127 const kernel_cap_t b)
128 {
129 kernel_cap_t dest;
130 CAP_BOP_ALL(dest, a, b, &);
131 return dest;
132 }
133
cap_drop(const kernel_cap_t a,const kernel_cap_t drop)134 static inline kernel_cap_t cap_drop(const kernel_cap_t a,
135 const kernel_cap_t drop)
136 {
137 kernel_cap_t dest;
138 CAP_BOP_ALL(dest, a, drop, &~);
139 return dest;
140 }
141
cap_invert(const kernel_cap_t c)142 static inline kernel_cap_t cap_invert(const kernel_cap_t c)
143 {
144 kernel_cap_t dest;
145 CAP_UOP_ALL(dest, c, ~);
146 return dest;
147 }
148
cap_isclear(const kernel_cap_t a)149 static inline bool cap_isclear(const kernel_cap_t a)
150 {
151 unsigned __capi;
152 CAP_FOR_EACH_U32(__capi) {
153 if (a.cap[__capi] != 0)
154 return false;
155 }
156 return true;
157 }
158
159 /*
160 * Check if "a" is a subset of "set".
161 * return true if ALL of the capabilities in "a" are also in "set"
162 * cap_issubset(0101, 1111) will return true
163 * return false if ANY of the capabilities in "a" are not in "set"
164 * cap_issubset(1111, 0101) will return false
165 */
cap_issubset(const kernel_cap_t a,const kernel_cap_t set)166 static inline bool cap_issubset(const kernel_cap_t a, const kernel_cap_t set)
167 {
168 kernel_cap_t dest;
169 dest = cap_drop(a, set);
170 return cap_isclear(dest);
171 }
172
173 /* Used to decide between falling back on the old suser() or fsuser(). */
174
cap_drop_fs_set(const kernel_cap_t a)175 static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a)
176 {
177 const kernel_cap_t __cap_fs_set = CAP_FS_SET;
178 return cap_drop(a, __cap_fs_set);
179 }
180
cap_raise_fs_set(const kernel_cap_t a,const kernel_cap_t permitted)181 static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a,
182 const kernel_cap_t permitted)
183 {
184 const kernel_cap_t __cap_fs_set = CAP_FS_SET;
185 return cap_combine(a,
186 cap_intersect(permitted, __cap_fs_set));
187 }
188
cap_drop_nfsd_set(const kernel_cap_t a)189 static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a)
190 {
191 const kernel_cap_t __cap_fs_set = CAP_NFSD_SET;
192 return cap_drop(a, __cap_fs_set);
193 }
194
cap_raise_nfsd_set(const kernel_cap_t a,const kernel_cap_t permitted)195 static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
196 const kernel_cap_t permitted)
197 {
198 const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET;
199 return cap_combine(a,
200 cap_intersect(permitted, __cap_nfsd_set));
201 }
202
203 #ifdef CONFIG_MULTIUSER
204 extern bool has_capability(struct task_struct *t, int cap);
205 extern bool has_ns_capability(struct task_struct *t,
206 struct user_namespace *ns, int cap);
207 extern bool has_capability_noaudit(struct task_struct *t, int cap);
208 extern bool has_ns_capability_noaudit(struct task_struct *t,
209 struct user_namespace *ns, int cap);
210 extern bool capable(int cap);
211 extern bool ns_capable(struct user_namespace *ns, int cap);
212 extern bool ns_capable_noaudit(struct user_namespace *ns, int cap);
213 extern bool ns_capable_setid(struct user_namespace *ns, int cap);
214 #else
has_capability(struct task_struct * t,int cap)215 static inline bool has_capability(struct task_struct *t, int cap)
216 {
217 return true;
218 }
has_ns_capability(struct task_struct * t,struct user_namespace * ns,int cap)219 static inline bool has_ns_capability(struct task_struct *t,
220 struct user_namespace *ns, int cap)
221 {
222 return true;
223 }
has_capability_noaudit(struct task_struct * t,int cap)224 static inline bool has_capability_noaudit(struct task_struct *t, int cap)
225 {
226 return true;
227 }
has_ns_capability_noaudit(struct task_struct * t,struct user_namespace * ns,int cap)228 static inline bool has_ns_capability_noaudit(struct task_struct *t,
229 struct user_namespace *ns, int cap)
230 {
231 return true;
232 }
capable(int cap)233 static inline bool capable(int cap)
234 {
235 return true;
236 }
ns_capable(struct user_namespace * ns,int cap)237 static inline bool ns_capable(struct user_namespace *ns, int cap)
238 {
239 return true;
240 }
ns_capable_noaudit(struct user_namespace * ns,int cap)241 static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap)
242 {
243 return true;
244 }
ns_capable_setid(struct user_namespace * ns,int cap)245 static inline bool ns_capable_setid(struct user_namespace *ns, int cap)
246 {
247 return true;
248 }
249 #endif /* CONFIG_MULTIUSER */
250 extern bool privileged_wrt_inode_uidgid(struct user_namespace *ns, const struct inode *inode);
251 extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap);
252 extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
253 extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns);
254
255 /* audit system wants to get cap info from files as well */
256 extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
257
258 extern int cap_convert_nscap(struct dentry *dentry, void **ivalue, size_t size);
259
260 #endif /* !_LINUX_CAPABILITY_H */
261
