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
22 extern int file_caps_enabled;
23
24 typedef struct { u64 val; } kernel_cap_t;
25
26 /* same as vfs_ns_cap_data but in cpu endian and always filled completely */
27 struct 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
37 struct file;
38 struct inode;
39 struct dentry;
40 struct task_struct;
41 struct user_namespace;
42 struct 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
77 static 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
83 static 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
89 static 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
95 static inline bool cap_isclear(const kernel_cap_t a)
96 {
97 return !a.val;
98 }
99
100 static 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 */
112 static 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
119 static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a)
120 {
121 return cap_drop(a, CAP_FS_SET);
122 }
123
124 static 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, cap_intersect(permitted, CAP_FS_SET));
128 }
129
130 static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a)
131 {
132 return cap_drop(a, CAP_NFSD_SET);
133 }
134
135 static 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, cap_intersect(permitted, CAP_NFSD_SET));
139 }
140
141 #ifdef CONFIG_MULTIUSER
142 extern bool has_capability(struct task_struct *t, int cap);
143 extern bool has_ns_capability(struct task_struct *t,
144 struct user_namespace *ns, int cap);
145 extern bool has_capability_noaudit(struct task_struct *t, int cap);
146 extern bool has_ns_capability_noaudit(struct task_struct *t,
147 struct user_namespace *ns, int cap);
148 extern bool capable(int cap);
149 extern bool ns_capable(struct user_namespace *ns, int cap);
150 extern bool ns_capable_noaudit(struct user_namespace *ns, int cap);
151 extern bool ns_capable_setid(struct user_namespace *ns, int cap);
152 #else
153 static inline bool has_capability(struct task_struct *t, int cap)
154 {
155 return true;
156 }
157 static inline bool has_ns_capability(struct task_struct *t,
158 struct user_namespace *ns, int cap)
159 {
160 return true;
161 }
162 static inline bool has_capability_noaudit(struct task_struct *t, int cap)
163 {
164 return true;
165 }
166 static inline bool has_ns_capability_noaudit(struct task_struct *t,
167 struct user_namespace *ns, int cap)
168 {
169 return true;
170 }
171 static inline bool capable(int cap)
172 {
173 return true;
174 }
175 static inline bool ns_capable(struct user_namespace *ns, int cap)
176 {
177 return true;
178 }
179 static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap)
180 {
181 return true;
182 }
183 static inline bool ns_capable_setid(struct user_namespace *ns, int cap)
184 {
185 return true;
186 }
187 #endif /* CONFIG_MULTIUSER */
188 bool privileged_wrt_inode_uidgid(struct user_namespace *ns,
189 struct mnt_idmap *idmap,
190 const struct inode *inode);
191 bool capable_wrt_inode_uidgid(struct mnt_idmap *idmap,
192 const struct inode *inode, int cap);
193 extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
194 extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns);
195 static inline bool perfmon_capable(void)
196 {
197 return capable(CAP_PERFMON) || capable(CAP_SYS_ADMIN);
198 }
199
200 static inline bool bpf_capable(void)
201 {
202 return capable(CAP_BPF) || capable(CAP_SYS_ADMIN);
203 }
204
205 static 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 */
212 int get_vfs_caps_from_disk(struct mnt_idmap *idmap,
213 const struct dentry *dentry,
214 struct cpu_vfs_cap_data *cpu_caps);
215
216 int cap_convert_nscap(struct mnt_idmap *idmap, struct dentry *dentry,
217 const void **ivalue, size_t size);
218
219 #endif /* !_LINUX_CAPABILITY_H */
220
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