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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 421083 : return !a.val;
98 : }
99 :
100 : static inline bool cap_isidentical(const kernel_cap_t a, const kernel_cap_t b)
101 : {
102 118042199 : 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 */
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