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
18
19#define _KERNEL_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_3
20#define _KERNEL_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3
21
22extern int file_caps_enabled;
23
24typedef struct kernel_cap_struct {
25 __u32 cap[_KERNEL_CAPABILITY_U32S];
26} kernel_cap_t;
27
28/* exact same as vfs_cap_data but in cpu endian and always filled completely */
29struct cpu_vfs_cap_data {
30 __u32 magic_etc;
31 kernel_cap_t permitted;
32 kernel_cap_t inheritable;
33};
34
35#define _USER_CAP_HEADER_SIZE (sizeof(struct __user_cap_header_struct))
36#define _KERNEL_CAP_T_SIZE (sizeof(kernel_cap_t))
37
38
39struct file;
40struct inode;
41struct dentry;
42struct task_struct;
43struct user_namespace;
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_LAST_U32 ((_KERNEL_CAPABILITY_U32S) - 1)
82#define CAP_LAST_U32_VALID_MASK (CAP_TO_MASK(CAP_LAST_CAP + 1) -1)
83
84# define CAP_EMPTY_SET ((kernel_cap_t){{ 0, 0 }})
85# define CAP_FULL_SET ((kernel_cap_t){{ ~0, CAP_LAST_U32_VALID_MASK }})
86# define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
87 | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \
88 CAP_FS_MASK_B1 } })
89# define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
90 | CAP_TO_MASK(CAP_SYS_RESOURCE), \
91 CAP_FS_MASK_B1 } })
92
93#endif /* _KERNEL_CAPABILITY_U32S != 2 */
94
95# define cap_clear(c) do { (c) = __cap_empty_set; } while (0)
96
97#define cap_raise(c, flag) ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag))
98#define cap_lower(c, flag) ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag))
99#define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag))
100
101#define CAP_BOP_ALL(c, a, b, OP) \
102do { \
103 unsigned __capi; \
104 CAP_FOR_EACH_U32(__capi) { \
105 c.cap[__capi] = a.cap[__capi] OP b.cap[__capi]; \
106 } \
107} while (0)
108
109#define CAP_UOP_ALL(c, a, OP) \
110do { \
111 unsigned __capi; \
112 CAP_FOR_EACH_U32(__capi) { \
113 c.cap[__capi] = OP a.cap[__capi]; \
114 } \
115} while (0)
116
117static inline kernel_cap_t cap_combine(const kernel_cap_t a,
118 const kernel_cap_t b)
119{
120 kernel_cap_t dest;
121 CAP_BOP_ALL(dest, a, b, |);
122 return dest;
123}
124
125static inline kernel_cap_t cap_intersect(const kernel_cap_t a,
126 const kernel_cap_t b)
127{
128 kernel_cap_t dest;
129 CAP_BOP_ALL(dest, a, b, &);
130 return dest;
131}
132
133static inline kernel_cap_t cap_drop(const kernel_cap_t a,
134 const kernel_cap_t drop)
135{
136 kernel_cap_t dest;
137 CAP_BOP_ALL(dest, a, drop, &~);
138 return dest;
139}
140
141static inline kernel_cap_t cap_invert(const kernel_cap_t c)
142{
143 kernel_cap_t dest;
144 CAP_UOP_ALL(dest, c, ~);
145 return dest;
146}
147
148static inline bool cap_isclear(const kernel_cap_t a)
149{
150 unsigned __capi;
151 CAP_FOR_EACH_U32(__capi) {
152 if (a.cap[__capi] != 0)
153 return false;
154 }
155 return true;
156}
157
158/*
159 * Check if "a" is a subset of "set".
160 * return true if ALL of the capabilities in "a" are also in "set"
161 * cap_issubset(0101, 1111) will return true
162 * return false if ANY of the capabilities in "a" are not in "set"
163 * cap_issubset(1111, 0101) will return false
164 */
165static inline bool cap_issubset(const kernel_cap_t a, const kernel_cap_t set)
166{
167 kernel_cap_t dest;
168 dest = cap_drop(a, set);
169 return cap_isclear(dest);
170}
171
172/* Used to decide between falling back on the old suser() or fsuser(). */
173
174static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a)
175{
176 const kernel_cap_t __cap_fs_set = CAP_FS_SET;
177 return cap_drop(a, __cap_fs_set);
178}
179
180static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a,
181 const kernel_cap_t permitted)
182{
183 const kernel_cap_t __cap_fs_set = CAP_FS_SET;
184 return cap_combine(a,
185 cap_intersect(permitted, __cap_fs_set));
186}
187
188static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a)
189{
190 const kernel_cap_t __cap_fs_set = CAP_NFSD_SET;
191 return cap_drop(a, __cap_fs_set);
192}
193
194static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
195 const kernel_cap_t permitted)
196{
197 const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET;
198 return cap_combine(a,
199 cap_intersect(permitted, __cap_nfsd_set));
200}
201
202#ifdef CONFIG_MULTIUSER
203extern bool has_capability(struct task_struct *t, int cap);
204extern bool has_ns_capability(struct task_struct *t,
205 struct user_namespace *ns, int cap);
206extern bool has_capability_noaudit(struct task_struct *t, int cap);
207extern bool has_ns_capability_noaudit(struct task_struct *t,
208 struct user_namespace *ns, int cap);
209extern bool capable(int cap);
210extern bool ns_capable(struct user_namespace *ns, int cap);
211extern bool ns_capable_noaudit(struct user_namespace *ns, int cap);
212#else
213static inline bool has_capability(struct task_struct *t, int cap)
214{
215 return true;
216}
217static inline bool has_ns_capability(struct task_struct *t,
218 struct user_namespace *ns, int cap)
219{
220 return true;
221}
222static inline bool has_capability_noaudit(struct task_struct *t, int cap)
223{
224 return true;
225}
226static inline bool has_ns_capability_noaudit(struct task_struct *t,
227 struct user_namespace *ns, int cap)
228{
229 return true;
230}
231static inline bool capable(int cap)
232{
233 return true;
234}
235static inline bool ns_capable(struct user_namespace *ns, int cap)
236{
237 return true;
238}
239static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap)
240{
241 return true;
242}
243#endif /* CONFIG_MULTIUSER */
244extern bool privileged_wrt_inode_uidgid(struct user_namespace *ns, const struct inode *inode);
245extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap);
246extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
247extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns);
248
249/* audit system wants to get cap info from files as well */
250extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
251
252extern int cap_convert_nscap(struct dentry *dentry, void **ivalue, size_t size);
253
254#endif /* !_LINUX_CAPABILITY_H */
255