projects/linux·blob v5.1-rc4 · refs

260 lines · 7.8 KiB

1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * This is <linux/capability.h>
4 *
5 * Andrew G. Morgan <[email protected]>
6 * Alexander Kjeldaas <[email protected]>
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
22extern int file_caps_enabled;
23
24typedef 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 */
29struct 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
40struct file;
41struct inode;
42struct dentry;
43struct task_struct;
44struct user_namespace;
45
46extern const kernel_cap_t __cap_empty_set;
47extern 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) \
103do { \
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) \
111do { \
112 unsigned __capi; \
113 CAP_FOR_EACH_U32(__capi) { \
114 c.cap[__capi] = OP a.cap[__capi]; \
115 } \
116} while (0)
117
118static 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
126static 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
134static 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
142static 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
149static 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 */
166static 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
175static 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
181static 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
189static 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
195static 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
204extern bool has_capability(struct task_struct *t, int cap);
205extern bool has_ns_capability(struct task_struct *t,
206 struct user_namespace *ns, int cap);
207extern bool has_capability_noaudit(struct task_struct *t, int cap);
208extern bool has_ns_capability_noaudit(struct task_struct *t,
209 struct user_namespace *ns, int cap);
210extern bool capable(int cap);
211extern bool ns_capable(struct user_namespace *ns, int cap);
212extern bool ns_capable_noaudit(struct user_namespace *ns, int cap);
213extern bool ns_capable_setid(struct user_namespace *ns, int cap);
214#else
215static inline bool has_capability(struct task_struct *t, int cap)
216{
217 return true;
218}
219static inline bool has_ns_capability(struct task_struct *t,
220 struct user_namespace *ns, int cap)
221{
222 return true;
223}
224static inline bool has_capability_noaudit(struct task_struct *t, int cap)
225{
226 return true;
227}
228static inline bool has_ns_capability_noaudit(struct task_struct *t,
229 struct user_namespace *ns, int cap)
230{
231 return true;
232}
233static inline bool capable(int cap)
234{
235 return true;
236}
237static inline bool ns_capable(struct user_namespace *ns, int cap)
238{
239 return true;
240}
241static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap)
242{
243 return true;
244}
245static inline bool ns_capable_setid(struct user_namespace *ns, int cap)
246{
247 return true;
248}
249#endif /* CONFIG_MULTIUSER */
250extern bool privileged_wrt_inode_uidgid(struct user_namespace *ns, const struct inode *inode);
251extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap);
252extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
253extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns);
254
255/* audit system wants to get cap info from files as well */
256extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
257
258extern int cap_convert_nscap(struct dentry *dentry, void **ivalue, size_t size);
259
260#endif /* !_LINUX_CAPABILITY_H */