linux/include/linux/capability.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * This is <linux/capability.h>
 *
 * Andrew G. Morgan <[email protected]>
 * Alexander Kjeldaas <[email protected]>
 * 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>
#include <linux/uidgid.h>
#include <linux/bits.h>

#define _KERNEL_CAPABILITY_VERSION …

extern int file_caps_enabled;

kernel_cap_t;

/* same as vfs_ns_cap_data but in cpu endian and always filled completely */
struct cpu_vfs_cap_data { … };

#define _USER_CAP_HEADER_SIZE …
#define _KERNEL_CAP_T_SIZE …

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 …
#define CAP_VALID_MASK …

#define CAP_EMPTY_SET …
#define CAP_FULL_SET …
#define CAP_FS_SET …
#define CAP_NFSD_SET …

#define cap_clear(c) …

#define cap_raise(c, flag) …
#define cap_lower(c, flag) …
#define cap_raised(c, flag) …

static inline kernel_cap_t cap_combine(const kernel_cap_t a,
				       const kernel_cap_t b)
{ … }

static inline kernel_cap_t cap_intersect(const kernel_cap_t a,
					 const kernel_cap_t b)
{ … }

static inline kernel_cap_t cap_drop(const kernel_cap_t a,
				    const kernel_cap_t drop)
{ … }

static inline bool cap_isclear(const kernel_cap_t a)
{ … }

static inline bool cap_isidentical(const kernel_cap_t a, const kernel_cap_t b)
{ … }

/*
 * 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)
{ … }

/* 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)
{ … }

static inline kernel_cap_t cap_raise_fs_set(const kernel_cap_t a,
					    const kernel_cap_t permitted)
{ … }

static inline kernel_cap_t cap_drop_nfsd_set(const kernel_cap_t a)
{ … }

static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
					      const kernel_cap_t permitted)
{ … }

#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);
extern bool ns_capable_noaudit(struct user_namespace *ns, int cap);
extern bool ns_capable_setid(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;
}
static inline bool ns_capable_noaudit(struct user_namespace *ns, int cap)
{
	return true;
}
static inline bool ns_capable_setid(struct user_namespace *ns, int cap)
{
	return true;
}
#endif /* CONFIG_MULTIUSER */
bool privileged_wrt_inode_uidgid(struct user_namespace *ns,
				 struct mnt_idmap *idmap,
				 const struct inode *inode);
bool capable_wrt_inode_uidgid(struct mnt_idmap *idmap,
			      const struct inode *inode, int cap);
extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);
extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns);
static inline bool perfmon_capable(void)
{ … }

static inline bool bpf_capable(void)
{ … }

static inline bool checkpoint_restore_ns_capable(struct user_namespace *ns)
{ … }

/* audit system wants to get cap info from files as well */
int get_vfs_caps_from_disk(struct mnt_idmap *idmap,
			   const struct dentry *dentry,
			   struct cpu_vfs_cap_data *cpu_caps);

int cap_convert_nscap(struct mnt_idmap *idmap, struct dentry *dentry,
		      const void **ivalue, size_t size);

#endif /* !_LINUX_CAPABILITY_H */