root/include/linux/capability.h

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INCLUDED FROM

DEFINITIONS

This source file includes following definitions.
  1. cap_combine
  2. cap_intersect
  3. cap_drop
  4. cap_invert
  5. cap_isclear
  6. cap_issubset
  7. cap_drop_fs_set
  8. cap_raise_fs_set
  9. cap_drop_nfsd_set
  10. cap_raise_nfsd_set
  11. has_capability
  12. has_ns_capability
  13. has_capability_noaudit
  14. has_ns_capability_noaudit
  15. capable
  16. ns_capable
  17. ns_capable_noaudit
  18. ns_capable_setid
   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 
 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 
 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 
 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 
 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 
 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  */
 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 
 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 
 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 
 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 
 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
 215 static inline bool has_capability(struct task_struct *t, int cap)
 216 {
 217         return true;
 218 }
 219 static inline bool has_ns_capability(struct task_struct *t,
 220                               struct user_namespace *ns, int cap)
 221 {
 222         return true;
 223 }
 224 static inline bool has_capability_noaudit(struct task_struct *t, int cap)
 225 {
 226         return true;
 227 }
 228 static inline bool has_ns_capability_noaudit(struct task_struct *t,
 229                                       struct user_namespace *ns, int cap)
 230 {
 231         return true;
 232 }
 233 static inline bool capable(int cap)
 234 {
 235         return true;
 236 }
 237 static inline bool ns_capable(struct user_namespace *ns, int cap)
 238 {
 239         return true;
 240 }
 241 static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap)
 242 {
 243         return true;
 244 }
 245 static inline bool ns_capable_setid(struct user_namespace *ns, int cap)
 246 {
 247         return true;
 248 }
 249 #endif /* CONFIG_MULTIUSER */
 250 extern bool privileged_wrt_inode_uidgid(struct user_namespace *ns, const struct inode *inode);
 251 extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap);
 252 extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
 253 extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns);
 254 
 255 /* audit system wants to get cap info from files as well */
 256 extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
 257 
 258 extern int cap_convert_nscap(struct dentry *dentry, void **ivalue, size_t size);
 259 
 260 #endif /* !_LINUX_CAPABILITY_H */
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