include/linux/capability.h

Source file repositories/reference/linux-study-clean/include/linux/capability.h

File Facts

System
Linux kernel
Corpus path
include/linux/capability.h
Extension
.h
Size
6463 bytes
Lines
221
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct cpu_vfs_cap_data {
	__u32 magic_etc;
	kuid_t rootid;
	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 task_struct;
struct user_namespace;
struct mnt_idmap;

/*
 * 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     (BIT_ULL(CAP_CHOWN)		\
			| BIT_ULL(CAP_MKNOD)		\
			| BIT_ULL(CAP_DAC_OVERRIDE)	\
			| BIT_ULL(CAP_DAC_READ_SEARCH)	\
			| BIT_ULL(CAP_FOWNER)		\
			| BIT_ULL(CAP_FSETID)		\
			| BIT_ULL(CAP_MAC_OVERRIDE))
#define CAP_VALID_MASK	 (BIT_ULL(CAP_LAST_CAP+1)-1)

# define CAP_EMPTY_SET    ((kernel_cap_t) { 0 })
# define CAP_FULL_SET     ((kernel_cap_t) { CAP_VALID_MASK })
# define CAP_FS_SET       ((kernel_cap_t) { CAP_FS_MASK | BIT_ULL(CAP_LINUX_IMMUTABLE) })
# define CAP_NFSD_SET     ((kernel_cap_t) { CAP_FS_MASK | BIT_ULL(CAP_SYS_RESOURCE) })

# define cap_clear(c)         do { (c).val = 0; } while (0)

#define cap_raise(c, flag)  ((c).val |= BIT_ULL(flag))
#define cap_lower(c, flag)  ((c).val &= ~BIT_ULL(flag))
#define cap_raised(c, flag) (((c).val & BIT_ULL(flag)) != 0)

static inline kernel_cap_t cap_combine(const kernel_cap_t a,
				       const kernel_cap_t b)
{
	return (kernel_cap_t) { a.val | b.val };
}

static inline kernel_cap_t cap_intersect(const kernel_cap_t a,
					 const kernel_cap_t b)
{
	return (kernel_cap_t) { a.val & b.val };
}

static inline kernel_cap_t cap_drop(const kernel_cap_t a,
				    const kernel_cap_t drop)
{
	return (kernel_cap_t) { a.val &~ drop.val };
}

static inline bool cap_isclear(const kernel_cap_t a)
{
	return !a.val;
}

static inline bool cap_isidentical(const kernel_cap_t a, const kernel_cap_t b)
{
	return a.val == b.val;
}

/*
 * 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)
{
	return !(a.val & ~set.val);
}

Annotation

Implementation Notes