linux/include/linux/capability.h
<<
>>
Prefs
   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
  21extern int file_caps_enabled;
  22
  23typedef 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 */
  28struct 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
  38struct inode;
  39struct dentry;
  40struct user_namespace;
  41
  42struct user_namespace *current_user_ns(void);
  43
  44extern const kernel_cap_t __cap_empty_set;
  45extern const kernel_cap_t __cap_init_eff_set;
  46
  47/*
  48 * Internal kernel functions only
  49 */
  50
  51#define CAP_FOR_EACH_U32(__capi)  \
  52        for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi)
  53
  54/*
  55 * CAP_FS_MASK and CAP_NFSD_MASKS:
  56 *
  57 * The fs mask is all the privileges that fsuid==0 historically meant.
  58 * At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE.
  59 *
  60 * It has never meant setting security.* and trusted.* xattrs.
  61 *
  62 * We could also define fsmask as follows:
  63 *   1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions
  64 *   2. The security.* and trusted.* xattrs are fs-related MAC permissions
  65 */
  66
  67# define CAP_FS_MASK_B0     (CAP_TO_MASK(CAP_CHOWN)             \
  68                            | CAP_TO_MASK(CAP_MKNOD)            \
  69                            | CAP_TO_MASK(CAP_DAC_OVERRIDE)     \
  70                            | CAP_TO_MASK(CAP_DAC_READ_SEARCH)  \
  71                            | CAP_TO_MASK(CAP_FOWNER)           \
  72                            | CAP_TO_MASK(CAP_FSETID))
  73
  74# define CAP_FS_MASK_B1     (CAP_TO_MASK(CAP_MAC_OVERRIDE))
  75
  76#if _KERNEL_CAPABILITY_U32S != 2
  77# error Fix up hand-coded capability macro initializers
  78#else /* HAND-CODED capability initializers */
  79
  80# define CAP_EMPTY_SET    ((kernel_cap_t){{ 0, 0 }})
  81# define CAP_FULL_SET     ((kernel_cap_t){{ ~0, ~0 }})
  82# define CAP_FS_SET       ((kernel_cap_t){{ CAP_FS_MASK_B0 \
  83                                    | CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \
  84                                    CAP_FS_MASK_B1 } })
  85# define CAP_NFSD_SET     ((kernel_cap_t){{ CAP_FS_MASK_B0 \
  86                                    | CAP_TO_MASK(CAP_SYS_RESOURCE), \
  87                                    CAP_FS_MASK_B1 } })
  88
  89#endif /* _KERNEL_CAPABILITY_U32S != 2 */
  90
  91# define cap_clear(c)         do { (c) = __cap_empty_set; } while (0)
  92
  93#define cap_raise(c, flag)  ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag))
  94#define cap_lower(c, flag)  ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag))
  95#define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag))
  96
  97#define CAP_BOP_ALL(c, a, b, OP)                                    \
  98do {                                                                \
  99        unsigned __capi;                                            \
 100        CAP_FOR_EACH_U32(__capi) {                                  \
 101                c.cap[__capi] = a.cap[__capi] OP b.cap[__capi];     \
 102        }                                                           \
 103} while (0)
 104
 105#define CAP_UOP_ALL(c, a, OP)                                       \
 106do {                                                                \
 107        unsigned __capi;                                            \
 108        CAP_FOR_EACH_U32(__capi) {                                  \
 109                c.cap[__capi] = OP a.cap[__capi];                   \
 110        }                                                           \
 111} while (0)
 112
 113static inline kernel_cap_t cap_combine(const kernel_cap_t a,
 114                                       const kernel_cap_t b)
 115{
 116        kernel_cap_t dest;
 117        CAP_BOP_ALL(dest, a, b, |);
 118        return dest;
 119}
 120
 121static inline kernel_cap_t cap_intersect(const kernel_cap_t a,
 122                                         const kernel_cap_t b)
 123{
 124        kernel_cap_t dest;
 125        CAP_BOP_ALL(dest, a, b, &);
 126        return dest;
 127}
 128
 129static inline kernel_cap_t cap_drop(const kernel_cap_t a,
 130                                    const kernel_cap_t drop)
 131{
 132        kernel_cap_t dest;
 133        CAP_BOP_ALL(dest, a, drop, &~);
 134        return dest;
 135}
 136
 137static inline kernel_cap_t cap_invert(const kernel_cap_t c)
 138{
 139        kernel_cap_t dest;
 140        CAP_UOP_ALL(dest, c, ~);
 141        return dest;
 142}
 143
 144static inline int cap_isclear(const kernel_cap_t a)
 145{
 146        unsigned __capi;
 147        CAP_FOR_EACH_U32(__capi) {
 148                if (a.cap[__capi] != 0)
 149                        return 0;
 150        }
 151        return 1;
 152}
 153
 154/*
 155 * Check if "a" is a subset of "set".
 156 * return 1 if ALL of the capabilities in "a" are also in "set"
 157 *      cap_issubset(0101, 1111) will return 1
 158 * return 0 if ANY of the capabilities in "a" are not in "set"
 159 *      cap_issubset(1111, 0101) will return 0
 160 */
 161static inline int cap_issubset(const kernel_cap_t a, const kernel_cap_t set)
 162{
 163        kernel_cap_t dest;
 164        dest = cap_drop(a, set);
 165        return cap_isclear(dest);
 166}
 167
 168/* Used to decide between falling back on the old suser() or fsuser(). */
 169
 170static inline int cap_is_fs_cap(int cap)
 171{
 172        const kernel_cap_t __cap_fs_set = CAP_FS_SET;
 173        return !!(CAP_TO_MASK(cap) & __cap_fs_set.cap[CAP_TO_INDEX(cap)]);
 174}
 175
 176static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a)
 177{
 178        const kernel_cap_t __cap_fs_set = CAP_FS_SET;
 179        return cap_drop(a, __cap_fs_set);
 180}
 181
 182static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a,
 183                                            const kernel_cap_t permitted)
 184{
 185        const kernel_cap_t __cap_fs_set = CAP_FS_SET;
 186        return cap_combine(a,
 187                           cap_intersect(permitted, __cap_fs_set));
 188}
 189
 190static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a)
 191{
 192        const kernel_cap_t __cap_fs_set = CAP_NFSD_SET;
 193        return cap_drop(a, __cap_fs_set);
 194}
 195
 196static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
 197                                              const kernel_cap_t permitted)
 198{
 199        const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET;
 200        return cap_combine(a,
 201                           cap_intersect(permitted, __cap_nfsd_set));
 202}
 203
 204extern bool has_capability(struct task_struct *t, int cap);
 205extern bool has_ns_capability(struct task_struct *t,
 206                              struct user_namespace *ns, int cap);
 207extern bool has_capability_noaudit(struct task_struct *t, int cap);
 208extern bool has_ns_capability_noaudit(struct task_struct *t,
 209                                      struct user_namespace *ns, int cap);
 210extern bool capable(int cap);
 211extern bool ns_capable(struct user_namespace *ns, int cap);
 212extern bool nsown_capable(int cap);
 213extern bool inode_capable(const struct inode *inode, int cap);
 214
 215/* audit system wants to get cap info from files as well */
 216extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
 217
 218#endif /* !_LINUX_CAPABILITY_H */
 219
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.