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 
19 #define _KERNEL_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_3
20 #define _KERNEL_CAPABILITY_U32S    _LINUX_CAPABILITY_U32S_3
21 
22 extern int file_caps_enabled;
23 
24 typedef 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 */
29 struct 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 
40 struct file;
41 struct inode;
42 struct dentry;
43 struct task_struct;
44 struct user_namespace;
45 
46 extern const kernel_cap_t __cap_empty_set;
47 extern 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)                                    \
103 do {                                                                \
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)                                       \
111 do {                                                                \
112 	unsigned __capi;                                            \
113 	CAP_FOR_EACH_U32(__capi) {                                  \
114 		c.cap[__capi] = OP a.cap[__capi];                   \
115 	}                                                           \
116 } while (0)
117 
cap_combine(const kernel_cap_t a,const kernel_cap_t b)118 static 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 
cap_intersect(const kernel_cap_t a,const kernel_cap_t b)126 static 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 
cap_drop(const kernel_cap_t a,const kernel_cap_t drop)134 static 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 
cap_invert(const kernel_cap_t c)142 static 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 
cap_isclear(const kernel_cap_t a)149 static 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  */
cap_issubset(const kernel_cap_t a,const kernel_cap_t set)166 static 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 
cap_drop_fs_set(const kernel_cap_t a)175 static 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 
cap_raise_fs_set(const kernel_cap_t a,const kernel_cap_t permitted)181 static 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 
cap_drop_nfsd_set(const kernel_cap_t a)189 static 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 
cap_raise_nfsd_set(const kernel_cap_t a,const kernel_cap_t permitted)195 static 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
204 extern bool has_capability(struct task_struct *t, int cap);
205 extern bool has_ns_capability(struct task_struct *t,
206 			      struct user_namespace *ns, int cap);
207 extern bool has_capability_noaudit(struct task_struct *t, int cap);
208 extern bool has_ns_capability_noaudit(struct task_struct *t,
209 				      struct user_namespace *ns, int cap);
210 extern bool capable(int cap);
211 extern bool ns_capable(struct user_namespace *ns, int cap);
212 extern bool ns_capable_noaudit(struct user_namespace *ns, int cap);
213 extern bool ns_capable_setid(struct user_namespace *ns, int cap);
214 #else
has_capability(struct task_struct * t,int cap)215 static inline bool has_capability(struct task_struct *t, int cap)
216 {
217 	return true;
218 }
has_ns_capability(struct task_struct * t,struct user_namespace * ns,int cap)219 static inline bool has_ns_capability(struct task_struct *t,
220 			      struct user_namespace *ns, int cap)
221 {
222 	return true;
223 }
has_capability_noaudit(struct task_struct * t,int cap)224 static inline bool has_capability_noaudit(struct task_struct *t, int cap)
225 {
226 	return true;
227 }
has_ns_capability_noaudit(struct task_struct * t,struct user_namespace * ns,int cap)228 static inline bool has_ns_capability_noaudit(struct task_struct *t,
229 				      struct user_namespace *ns, int cap)
230 {
231 	return true;
232 }
capable(int cap)233 static inline bool capable(int cap)
234 {
235 	return true;
236 }
ns_capable(struct user_namespace * ns,int cap)237 static inline bool ns_capable(struct user_namespace *ns, int cap)
238 {
239 	return true;
240 }
ns_capable_noaudit(struct user_namespace * ns,int cap)241 static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap)
242 {
243 	return true;
244 }
ns_capable_setid(struct user_namespace * ns,int cap)245 static inline bool ns_capable_setid(struct user_namespace *ns, int cap)
246 {
247 	return true;
248 }
249 #endif /* CONFIG_MULTIUSER */
250 bool privileged_wrt_inode_uidgid(struct user_namespace *ns,
251 				 struct user_namespace *mnt_userns,
252 				 const struct inode *inode);
253 bool capable_wrt_inode_uidgid(struct user_namespace *mnt_userns,
254 			      const struct inode *inode, int cap);
255 extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
256 extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns);
perfmon_capable(void)257 static inline bool perfmon_capable(void)
258 {
259 	return capable(CAP_PERFMON) || capable(CAP_SYS_ADMIN);
260 }
261 
bpf_capable(void)262 static inline bool bpf_capable(void)
263 {
264 	return capable(CAP_BPF) || capable(CAP_SYS_ADMIN);
265 }
266 
checkpoint_restore_ns_capable(struct user_namespace * ns)267 static inline bool checkpoint_restore_ns_capable(struct user_namespace *ns)
268 {
269 	return ns_capable(ns, CAP_CHECKPOINT_RESTORE) ||
270 		ns_capable(ns, CAP_SYS_ADMIN);
271 }
272 
273 /* audit system wants to get cap info from files as well */
274 int get_vfs_caps_from_disk(struct user_namespace *mnt_userns,
275 			   const struct dentry *dentry,
276 			   struct cpu_vfs_cap_data *cpu_caps);
277 
278 int cap_convert_nscap(struct user_namespace *mnt_userns, struct dentry *dentry,
279 		      const void **ivalue, size_t size);
280 
281 #endif /* !_LINUX_CAPABILITY_H */
282