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/*
* This is <linux/capability.h>
*
* Andrew G. Morgan <morgan@kernel.org>
* Alexander Kjeldaas <astor@guardian.no>
* with help from Aleph1, Roland Buresund and Andrew Main.
*
* See here for the libcap library ("POSIX draft" compliance):
*
* ftp://www.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.6/
*/
#ifndef _LINUX_CAPABILITY_H
#define _LINUX_CAPABILITY_H
#include <uapi/linux/capability.h>
#define _KERNEL_CAPABILITY_VERSION _LINUX_CAPABILITY_VERSION_3
#define _KERNEL_CAPABILITY_U32S _LINUX_CAPABILITY_U32S_3
extern int file_caps_enabled;
typedef struct kernel_cap_struct {
__u32 cap[_KERNEL_CAPABILITY_U32S];
} kernel_cap_t;
/* exact same as vfs_cap_data but in cpu endian and always filled completely */
struct cpu_vfs_cap_data {
__u32 magic_etc;
kernel_cap_t permitted;
kernel_cap_t inheritable;
};
#define _USER_CAP_HEADER_SIZE (sizeof(struct __user_cap_header_struct))
#define _KERNEL_CAP_T_SIZE (sizeof(kernel_cap_t))
struct file;
struct inode;
struct dentry;
struct user_namespace;
extern const kernel_cap_t __cap_empty_set;
extern const kernel_cap_t __cap_init_eff_set;
/*
* Internal kernel functions only
*/
#define CAP_FOR_EACH_U32(__capi) \
for (__capi = 0; __capi < _KERNEL_CAPABILITY_U32S; ++__capi)
/*
* CAP_FS_MASK and CAP_NFSD_MASKS:
*
* The fs mask is all the privileges that fsuid==0 historically meant.
* At one time in the past, that included CAP_MKNOD and CAP_LINUX_IMMUTABLE.
*
* It has never meant setting security.* and trusted.* xattrs.
*
* We could also define fsmask as follows:
* 1. CAP_FS_MASK is the privilege to bypass all fs-related DAC permissions
* 2. The security.* and trusted.* xattrs are fs-related MAC permissions
*/
# define CAP_FS_MASK_B0 (CAP_TO_MASK(CAP_CHOWN) \
| CAP_TO_MASK(CAP_MKNOD) \
| CAP_TO_MASK(CAP_DAC_OVERRIDE) \
| CAP_TO_MASK(CAP_DAC_READ_SEARCH) \
| CAP_TO_MASK(CAP_FOWNER) \
| CAP_TO_MASK(CAP_FSETID))
# define CAP_FS_MASK_B1 (CAP_TO_MASK(CAP_MAC_OVERRIDE))
#if _KERNEL_CAPABILITY_U32S != 2
# error Fix up hand-coded capability macro initializers
#else /* HAND-CODED capability initializers */
#define CAP_LAST_U32 ((_KERNEL_CAPABILITY_U32S) - 1)
#define CAP_LAST_U32_VALID_MASK (CAP_TO_MASK(CAP_LAST_CAP + 1) -1)
# define CAP_EMPTY_SET ((kernel_cap_t){{ 0, 0 }})
# define CAP_FULL_SET ((kernel_cap_t){{ ~0, CAP_LAST_U32_VALID_MASK }})
# define CAP_FS_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
| CAP_TO_MASK(CAP_LINUX_IMMUTABLE), \
CAP_FS_MASK_B1 } })
# define CAP_NFSD_SET ((kernel_cap_t){{ CAP_FS_MASK_B0 \
| CAP_TO_MASK(CAP_SYS_RESOURCE), \
CAP_FS_MASK_B1 } })
#endif /* _KERNEL_CAPABILITY_U32S != 2 */
# define cap_clear(c) do { (c) = __cap_empty_set; } while (0)
#define cap_raise(c, flag) ((c).cap[CAP_TO_INDEX(flag)] |= CAP_TO_MASK(flag))
#define cap_lower(c, flag) ((c).cap[CAP_TO_INDEX(flag)] &= ~CAP_TO_MASK(flag))
#define cap_raised(c, flag) ((c).cap[CAP_TO_INDEX(flag)] & CAP_TO_MASK(flag))
#define CAP_BOP_ALL(c, a, b, OP) \
do { \
unsigned __capi; \
CAP_FOR_EACH_U32(__capi) { \
c.cap[__capi] = a.cap[__capi] OP b.cap[__capi]; \
} \
} while (0)
#define CAP_UOP_ALL(c, a, OP) \
do { \
unsigned __capi; \
CAP_FOR_EACH_U32(__capi) { \
c.cap[__capi] = OP a.cap[__capi]; \
} \
} while (0)
static inline kernel_cap_t cap_combine(const kernel_cap_t a,
const kernel_cap_t b)
{
kernel_cap_t dest;
CAP_BOP_ALL(dest, a, b, |);
return dest;
}
static inline kernel_cap_t cap_intersect(const kernel_cap_t a,
const kernel_cap_t b)
{
kernel_cap_t dest;
CAP_BOP_ALL(dest, a, b, &);
return dest;
}
static inline kernel_cap_t cap_drop(const kernel_cap_t a,
const kernel_cap_t drop)
{
kernel_cap_t dest;
CAP_BOP_ALL(dest, a, drop, &~);
return dest;
}
static inline kernel_cap_t cap_invert(const kernel_cap_t c)
{
kernel_cap_t dest;
CAP_UOP_ALL(dest, c, ~);
return dest;
}
static inline bool cap_isclear(const kernel_cap_t a)
{
unsigned __capi;
CAP_FOR_EACH_U32(__capi) {
if (a.cap[__capi] != 0)
return false;
}
return true;
}
/*
* Check if "a" is a subset of "set".
* return true if ALL of the capabilities in "a" are also in "set"
* cap_issubset(0101, 1111) will return true
* return false if ANY of the capabilities in "a" are not in "set"
* cap_issubset(1111, 0101) will return false
*/
static inline bool cap_issubset(const kernel_cap_t a, const kernel_cap_t set)
{
kernel_cap_t dest;
dest = cap_drop(a, set);
return cap_isclear(dest);
}
/* Used to decide between falling back on the old suser() or fsuser(). */
static inline kernel_cap_t cap_drop_fs_set(const kernel_cap_t a)
{
const kernel_cap_t __cap_fs_set = CAP_FS_SET;
return cap_drop(a, __cap_fs_set);
}
static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a,
const kernel_cap_t permitted)
{
const kernel_cap_t __cap_fs_set = CAP_FS_SET;
return cap_combine(a,
cap_intersect(permitted, __cap_fs_set));
}
static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a)
{
const kernel_cap_t __cap_fs_set = CAP_NFSD_SET;
return cap_drop(a, __cap_fs_set);
}
static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
const kernel_cap_t permitted)
{
const kernel_cap_t __cap_nfsd_set = CAP_NFSD_SET;
return cap_combine(a,
cap_intersect(permitted, __cap_nfsd_set));
}
#ifdef CONFIG_MULTIUSER
extern bool has_capability(struct task_struct *t, int cap);
extern bool has_ns_capability(struct task_struct *t,
struct user_namespace *ns, int cap);
extern bool has_capability_noaudit(struct task_struct *t, int cap);
extern bool has_ns_capability_noaudit(struct task_struct *t,
struct user_namespace *ns, int cap);
extern bool capable(int cap);
extern bool ns_capable(struct user_namespace *ns, int cap);
#else
static inline bool has_capability(struct task_struct *t, int cap)
{
return true;
}
static inline bool has_ns_capability(struct task_struct *t,
struct user_namespace *ns, int cap)
{
return true;
}
static inline bool has_capability_noaudit(struct task_struct *t, int cap)
{
return true;
}
static inline bool has_ns_capability_noaudit(struct task_struct *t,
struct user_namespace *ns, int cap)
{
return true;
}
static inline bool capable(int cap)
{
return true;
}
static inline bool ns_capable(struct user_namespace *ns, int cap)
{
return true;
}
#endif /* CONFIG_MULTIUSER */
extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap);
extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
/* audit system wants to get cap info from files as well */
extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
#endif /* !_LINUX_CAPABILITY_H */
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