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1 | /* | |
2 | * This is <linux/capability.h> | |
3 | * | |
4 | * Andrew G. Morgan <morgan@kernel.org> | |
5 | * Alexander Kjeldaas <astor@guardian.no> | |
6 | * with help from Aleph1, Roland Buresund and Andrew Main. | |
7 | * | |
8 | * See here for the libcap library ("POSIX draft" compliance): | |
9 | * | |
10 | * ftp://www.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.6/ | |
11 | */ | |
12 | #ifndef _LINUX_CAPABILITY_H | |
13 | #define _LINUX_CAPABILITY_H | |
14 | ||
15 | #include <uapi/linux/capability.h> | |
16 | ||
17 | ||
18 | #define _KERNEL_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_3 | |
19 | #define _KERNEL_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3 | |
20 | ||
21 | extern int file_caps_enabled; | |
22 | ||
23 | typedef struct kernel_cap_struct { | |
24 | __u32 cap[_KERNEL_CAPABILITY_U32S]; | |
25 | } kernel_cap_t; | |
26 | ||
27 | /* exact same as vfs_cap_data but in cpu endian and always filled completely */ | |
28 | struct cpu_vfs_cap_data { | |
29 | __u32 magic_etc; | |
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 | ||
38 | struct file; | |
39 | struct inode; | |
40 | struct dentry; | |
41 | struct user_namespace; | |
42 | ||
43 | extern const kernel_cap_t __cap_empty_set; | |
44 | extern const kernel_cap_t __cap_init_eff_set; | |
45 | ||
46 | /* | |
47 | * Internal kernel functions only | |
48 | */ | |
49 | ||
50 | #define CAP_FOR_EACH_U32(__capi) \ | |
51 | for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi) | |
52 | ||
53 | /* | |
54 | * CAP_FS_MASK and CAP_NFSD_MASKS: | |
55 | * | |
56 | * The fs mask is all the privileges that fsuid==0 historically meant. | |
57 | * At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE. | |
58 | * | |
59 | * It has never meant setting security.* and trusted.* xattrs. | |
60 | * | |
61 | * We could also define fsmask as follows: | |
62 | * 1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions | |
63 | * 2. The security.* and trusted.* xattrs are fs-related MAC permissions | |
64 | */ | |
65 | ||
66 | # define CAP_FS_MASK_B0 (CAP_TO_MASK(CAP_CHOWN) \ | |
67 | | CAP_TO_MASK(CAP_MKNOD) \ | |
68 | | CAP_TO_MASK(CAP_DAC_OVERRIDE) \ | |
69 | | CAP_TO_MASK(CAP_DAC_READ_SEARCH) \ | |
70 | | CAP_TO_MASK(CAP_FOWNER) \ | |
71 | | CAP_TO_MASK(CAP_FSETID)) | |
72 | ||
73 | # define CAP_FS_MASK_B1 (CAP_TO_MASK(CAP_MAC_OVERRIDE)) | |
74 | ||
75 | #if _KERNEL_CAPABILITY_U32S != 2 | |
76 | # error Fix up hand-coded capability macro initializers | |
77 | #else /* HAND-CODED capability initializers */ | |
78 | ||
79 | #define CAP_LAST_U32 ((_KERNEL_CAPABILITY_U32S) - 1) | |
80 | #define CAP_LAST_U32_VALID_MASK (CAP_TO_MASK(CAP_LAST_CAP + 1) -1) | |
81 | ||
82 | # define CAP_EMPTY_SET ((kernel_cap_t){{ 0, 0 }}) | |
83 | # define CAP_FULL_SET ((kernel_cap_t){{ ~0, CAP_LAST_U32_VALID_MASK }}) | |
84 | # define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \ | |
85 | | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \ | |
86 | CAP_FS_MASK_B1 } }) | |
87 | # define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \ | |
88 | | CAP_TO_MASK(CAP_SYS_RESOURCE), \ | |
89 | CAP_FS_MASK_B1 } }) | |
90 | ||
91 | #endif /* _KERNEL_CAPABILITY_U32S != 2 */ | |
92 | ||
93 | # define cap_clear(c) do { (c) = __cap_empty_set; } while (0) | |
94 | ||
95 | #define cap_raise(c, flag) ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag)) | |
96 | #define cap_lower(c, flag) ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag)) | |
97 | #define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag)) | |
98 | ||
99 | #define CAP_BOP_ALL(c, a, b, OP) \ | |
100 | do { \ | |
101 | unsigned __capi; \ | |
102 | CAP_FOR_EACH_U32(__capi) { \ | |
103 | c.cap[__capi] = a.cap[__capi] OP b.cap[__capi]; \ | |
104 | } \ | |
105 | } while (0) | |
106 | ||
107 | #define CAP_UOP_ALL(c, a, OP) \ | |
108 | do { \ | |
109 | unsigned __capi; \ | |
110 | CAP_FOR_EACH_U32(__capi) { \ | |
111 | c.cap[__capi] = OP a.cap[__capi]; \ | |
112 | } \ | |
113 | } while (0) | |
114 | ||
115 | static inline kernel_cap_t cap_combine(const kernel_cap_t a, | |
116 | const kernel_cap_t b) | |
117 | { | |
118 | kernel_cap_t dest; | |
119 | CAP_BOP_ALL(dest, a, b, |); | |
120 | return dest; | |
121 | } | |
122 | ||
123 | static inline kernel_cap_t cap_intersect(const kernel_cap_t a, | |
124 | const kernel_cap_t b) | |
125 | { | |
126 | kernel_cap_t dest; | |
127 | CAP_BOP_ALL(dest, a, b, &); | |
128 | return dest; | |
129 | } | |
130 | ||
131 | static inline kernel_cap_t cap_drop(const kernel_cap_t a, | |
132 | const kernel_cap_t drop) | |
133 | { | |
134 | kernel_cap_t dest; | |
135 | CAP_BOP_ALL(dest, a, drop, &~); | |
136 | return dest; | |
137 | } | |
138 | ||
139 | static inline kernel_cap_t cap_invert(const kernel_cap_t c) | |
140 | { | |
141 | kernel_cap_t dest; | |
142 | CAP_UOP_ALL(dest, c, ~); | |
143 | return dest; | |
144 | } | |
145 | ||
146 | static inline bool cap_isclear(const kernel_cap_t a) | |
147 | { | |
148 | unsigned __capi; | |
149 | CAP_FOR_EACH_U32(__capi) { | |
150 | if (a.cap[__capi] != 0) | |
151 | return false; | |
152 | } | |
153 | return true; | |
154 | } | |
155 | ||
156 | /* | |
157 | * Check if "a" is a subset of "set". | |
158 | * return true if ALL of the capabilities in "a" are also in "set" | |
159 | * cap_issubset(0101, 1111) will return true | |
160 | * return false if ANY of the capabilities in "a" are not in "set" | |
161 | * cap_issubset(1111, 0101) will return false | |
162 | */ | |
163 | static inline bool cap_issubset(const kernel_cap_t a, const kernel_cap_t set) | |
164 | { | |
165 | kernel_cap_t dest; | |
166 | dest = cap_drop(a, set); | |
167 | return cap_isclear(dest); | |
168 | } | |
169 | ||
170 | /* Used to decide between falling back on the old suser() or fsuser(). */ | |
171 | ||
172 | static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a) | |
173 | { | |
174 | const kernel_cap_t __cap_fs_set = CAP_FS_SET; | |
175 | return cap_drop(a, __cap_fs_set); | |
176 | } | |
177 | ||
178 | static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a, | |
179 | const kernel_cap_t permitted) | |
180 | { | |
181 | const kernel_cap_t __cap_fs_set = CAP_FS_SET; | |
182 | return cap_combine(a, | |
183 | cap_intersect(permitted, __cap_fs_set)); | |
184 | } | |
185 | ||
186 | static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a) | |
187 | { | |
188 | const kernel_cap_t __cap_fs_set = CAP_NFSD_SET; | |
189 | return cap_drop(a, __cap_fs_set); | |
190 | } | |
191 | ||
192 | static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a, | |
193 | const kernel_cap_t permitted) | |
194 | { | |
195 | const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET; | |
196 | return cap_combine(a, | |
197 | cap_intersect(permitted, __cap_nfsd_set)); | |
198 | } | |
199 | ||
200 | #ifdef CONFIG_MULTIUSER | |
201 | extern bool has_capability(struct task_struct *t, int cap); | |
202 | extern bool has_ns_capability(struct task_struct *t, | |
203 | struct user_namespace *ns, int cap); | |
204 | extern bool has_capability_noaudit(struct task_struct *t, int cap); | |
205 | extern bool has_ns_capability_noaudit(struct task_struct *t, | |
206 | struct user_namespace *ns, int cap); | |
207 | extern bool capable(int cap); | |
208 | extern bool ns_capable(struct user_namespace *ns, int cap); | |
209 | #else | |
210 | static inline bool has_capability(struct task_struct *t, int cap) | |
211 | { | |
212 | return true; | |
213 | } | |
214 | static inline bool has_ns_capability(struct task_struct *t, | |
215 | struct user_namespace *ns, int cap) | |
216 | { | |
217 | return true; | |
218 | } | |
219 | static inline bool has_capability_noaudit(struct task_struct *t, int cap) | |
220 | { | |
221 | return true; | |
222 | } | |
223 | static inline bool has_ns_capability_noaudit(struct task_struct *t, | |
224 | struct user_namespace *ns, int cap) | |
225 | { | |
226 | return true; | |
227 | } | |
228 | static inline bool capable(int cap) | |
229 | { | |
230 | return true; | |
231 | } | |
232 | static inline bool ns_capable(struct user_namespace *ns, int cap) | |
233 | { | |
234 | return true; | |
235 | } | |
236 | #endif /* CONFIG_MULTIUSER */ | |
237 | extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap); | |
238 | extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap); | |
239 | ||
240 | /* audit system wants to get cap info from files as well */ | |
241 | extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps); | |
242 | ||
243 | #endif /* !_LINUX_CAPABILITY_H */ |