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#include <linux/bits.h>
19
20#define _KERNEL_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_3
21
22extern int file_caps_enabled;
23
24typedef struct { u64 val; } kernel_cap_t;
25
26/* same as vfs_ns_cap_data but in cpu endian and always filled completely */
27struct cpu_vfs_cap_data {
28 __u32 magic_etc;
29 kuid_t rootid;
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
37struct file;
38struct inode;
39struct dentry;
40struct task_struct;
41struct user_namespace;
42struct mnt_idmap;
43
44/*
45 * CAP_FS_MASK and CAP_NFSD_MASKS:
46 *
47 * The fs mask is all the privileges that fsuid==0 historically meant.
48 * At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE.
49 *
50 * It has never meant setting security.* and trusted.* xattrs.
51 *
52 * We could also define fsmask as follows:
53 * 1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions
54 * 2. The security.* and trusted.* xattrs are fs-related MAC permissions
55 */
56
57# define CAP_FS_MASK (BIT_ULL(CAP_CHOWN) \
58 | BIT_ULL(CAP_MKNOD) \
59 | BIT_ULL(CAP_DAC_OVERRIDE) \
60 | BIT_ULL(CAP_DAC_READ_SEARCH) \
61 | BIT_ULL(CAP_FOWNER) \
62 | BIT_ULL(CAP_FSETID) \
63 | BIT_ULL(CAP_MAC_OVERRIDE))
64#define CAP_VALID_MASK (BIT_ULL(CAP_LAST_CAP+1)-1)
65
66# define CAP_EMPTY_SET ((kernel_cap_t) { 0 })
67# define CAP_FULL_SET ((kernel_cap_t) { CAP_VALID_MASK })
68# define CAP_FS_SET ((kernel_cap_t) { CAP_FS_MASK | BIT_ULL(CAP_LINUX_IMMUTABLE) })
69# define CAP_NFSD_SET ((kernel_cap_t) { CAP_FS_MASK | BIT_ULL(CAP_SYS_RESOURCE) })
70
71# define cap_clear(c) do { (c).val = 0; } while (0)
72
73#define cap_raise(c, flag) ((c).val |= BIT_ULL(flag))
74#define cap_lower(c, flag) ((c).val &= ~BIT_ULL(flag))
75#define cap_raised(c, flag) (((c).val & BIT_ULL(flag)) != 0)
76
77static inline kernel_cap_t cap_combine(const kernel_cap_t a,
78 const kernel_cap_t b)
79{
80 return (kernel_cap_t) { a.val | b.val };
81}
82
83static inline kernel_cap_t cap_intersect(const kernel_cap_t a,
84 const kernel_cap_t b)
85{
86 return (kernel_cap_t) { a.val & b.val };
87}
88
89static inline kernel_cap_t cap_drop(const kernel_cap_t a,
90 const kernel_cap_t drop)
91{
92 return (kernel_cap_t) { a.val &~ drop.val };
93}
94
95static inline bool cap_isclear(const kernel_cap_t a)
96{
97 return !a.val;
98}
99
100static inline bool cap_isidentical(const kernel_cap_t a, const kernel_cap_t b)
101{
102 return a.val == b.val;
103}
104
105/*
106 * Check if "a" is a subset of "set".
107 * return true if ALL of the capabilities in "a" are also in "set"
108 * cap_issubset(0101, 1111) will return true
109 * return false if ANY of the capabilities in "a" are not in "set"
110 * cap_issubset(1111, 0101) will return false
111 */
112static inline bool cap_issubset(const kernel_cap_t a, const kernel_cap_t set)
113{
114 return !(a.val & ~set.val);
115}
116
117/* Used to decide between falling back on the old suser() or fsuser(). */
118
119static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a)
120{
121 return cap_drop(a, CAP_FS_SET);
122}
123
124static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a,
125 const kernel_cap_t permitted)
126{
127 return cap_combine(a, b: cap_intersect(a: permitted, CAP_FS_SET));
128}
129
130static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a)
131{
132 return cap_drop(a, CAP_NFSD_SET);
133}
134
135static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
136 const kernel_cap_t permitted)
137{
138 return cap_combine(a, b: cap_intersect(a: permitted, CAP_NFSD_SET));
139}
140
141#ifdef CONFIG_MULTIUSER
142extern bool has_capability(struct task_struct *t, int cap);
143extern bool has_ns_capability(struct task_struct *t,
144 struct user_namespace *ns, int cap);
145extern bool has_capability_noaudit(struct task_struct *t, int cap);
146extern bool has_ns_capability_noaudit(struct task_struct *t,
147 struct user_namespace *ns, int cap);
148extern bool capable(int cap);
149extern bool ns_capable(struct user_namespace *ns, int cap);
150extern bool ns_capable_noaudit(struct user_namespace *ns, int cap);
151extern bool ns_capable_setid(struct user_namespace *ns, int cap);
152#else
153static inline bool has_capability(struct task_struct *t, int cap)
154{
155 return true;
156}
157static inline bool has_ns_capability(struct task_struct *t,
158 struct user_namespace *ns, int cap)
159{
160 return true;
161}
162static inline bool has_capability_noaudit(struct task_struct *t, int cap)
163{
164 return true;
165}
166static inline bool has_ns_capability_noaudit(struct task_struct *t,
167 struct user_namespace *ns, int cap)
168{
169 return true;
170}
171static inline bool capable(int cap)
172{
173 return true;
174}
175static inline bool ns_capable(struct user_namespace *ns, int cap)
176{
177 return true;
178}
179static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap)
180{
181 return true;
182}
183static inline bool ns_capable_setid(struct user_namespace *ns, int cap)
184{
185 return true;
186}
187#endif /* CONFIG_MULTIUSER */
188bool privileged_wrt_inode_uidgid(struct user_namespace *ns,
189 struct mnt_idmap *idmap,
190 const struct inode *inode);
191bool capable_wrt_inode_uidgid(struct mnt_idmap *idmap,
192 const struct inode *inode, int cap);
193extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
194extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns);
195static inline bool perfmon_capable(void)
196{
197 return capable(CAP_PERFMON) || capable(CAP_SYS_ADMIN);
198}
199
200static inline bool bpf_capable(void)
201{
202 return capable(CAP_BPF) || capable(CAP_SYS_ADMIN);
203}
204
205static inline bool checkpoint_restore_ns_capable(struct user_namespace *ns)
206{
207 return ns_capable(ns, CAP_CHECKPOINT_RESTORE) ||
208 ns_capable(ns, CAP_SYS_ADMIN);
209}
210
211/* audit system wants to get cap info from files as well */
212int get_vfs_caps_from_disk(struct mnt_idmap *idmap,
213 const struct dentry *dentry,
214 struct cpu_vfs_cap_data *cpu_caps);
215
216int cap_convert_nscap(struct mnt_idmap *idmap, struct dentry *dentry,
217 const void **ivalue, size_t size);
218
219#endif /* !_LINUX_CAPABILITY_H */
220

source code of linux/include/linux/capability.h