include/linux/key.h - third_party/kernel - Git at Google

 /* SPDX-License-Identifier: GPL-2.0-or-later */
 /* Authentication token and access key management
  *
  * Copyright (C) 2004, 2007 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
  *
  * See Documentation/security/keys/core.rst for information on keys/keyrings.
  */

 #ifndef _LINUX_KEY_H
 #define _LINUX_KEY_H

 #include <linux/types.h>
 #include <linux/list.h>
 #include <linux/rbtree.h>
 #include <linux/rcupdate.h>
 #include <linux/sysctl.h>
 #include <linux/rwsem.h>
 #include <linux/atomic.h>
 #include <linux/assoc_array.h>
 #include <linux/refcount.h>
 #include <linux/time64.h>

 #ifdef __KERNEL__
 #include <linux/uidgid.h>

 /* key handle serial number */
 typedef int32_t key_serial_t;

 /* key handle permissions mask */
 typedef uint32_t key_perm_t;

 struct key;
 struct net;

 #ifdef CONFIG_KEYS

 #undef KEY_DEBUGGING

 #define KEY_POS_VIEW	0x01000000	/* possessor can view a key's attributes */
 #define KEY_POS_READ	0x02000000	/* possessor can read key payload / view keyring */
 #define KEY_POS_WRITE	0x04000000	/* possessor can update key payload / add link to keyring */
 #define KEY_POS_SEARCH	0x08000000	/* possessor can find a key in search / search a keyring */
 #define KEY_POS_LINK	0x10000000	/* possessor can create a link to a key/keyring */
 #define KEY_POS_SETATTR	0x20000000	/* possessor can set key attributes */
 #define KEY_POS_ALL	0x3f000000

 #define KEY_USR_VIEW	0x00010000	/* user permissions... */
 #define KEY_USR_READ	0x00020000
 #define KEY_USR_WRITE	0x00040000
 #define KEY_USR_SEARCH	0x00080000
 #define KEY_USR_LINK	0x00100000
 #define KEY_USR_SETATTR	0x00200000
 #define KEY_USR_ALL	0x003f0000

 #define KEY_GRP_VIEW	0x00000100	/* group permissions... */
 #define KEY_GRP_READ	0x00000200
 #define KEY_GRP_WRITE	0x00000400
 #define KEY_GRP_SEARCH	0x00000800
 #define KEY_GRP_LINK	0x00001000
 #define KEY_GRP_SETATTR	0x00002000
 #define KEY_GRP_ALL	0x00003f00

 #define KEY_OTH_VIEW	0x00000001	/* third party permissions... */
 #define KEY_OTH_READ	0x00000002
 #define KEY_OTH_WRITE	0x00000004
 #define KEY_OTH_SEARCH	0x00000008
 #define KEY_OTH_LINK	0x00000010
 #define KEY_OTH_SETATTR	0x00000020
 #define KEY_OTH_ALL	0x0000003f

 #define KEY_PERM_UNDEF	0xffffffff

 /*
  * The permissions required on a key that we're looking up.
  */
 enum key_need_perm {
 	KEY_NEED_UNSPECIFIED,	/* Needed permission unspecified */
 	KEY_NEED_VIEW,		/* Require permission to view attributes */
 	KEY_NEED_READ,		/* Require permission to read content */
 	KEY_NEED_WRITE,		/* Require permission to update / modify */
 	KEY_NEED_SEARCH,	/* Require permission to search (keyring) or find (key) */
 	KEY_NEED_LINK,		/* Require permission to link */
 	KEY_NEED_SETATTR,	/* Require permission to change attributes */
 	KEY_NEED_UNLINK,	/* Require permission to unlink key */
 	KEY_SYSADMIN_OVERRIDE,	/* Special: override by CAP_SYS_ADMIN */
 	KEY_AUTHTOKEN_OVERRIDE,	/* Special: override by possession of auth token */
 	KEY_DEFER_PERM_CHECK,	/* Special: permission check is deferred */
 };

 struct seq_file;
 struct user_struct;
 struct signal_struct;
 struct cred;

 struct key_type;
 struct key_owner;
 struct key_tag;
 struct keyring_list;
 struct keyring_name;

 struct key_tag {
 	struct rcu_head		rcu;
 	refcount_t		usage;
 	bool			removed;	/* T when subject removed */
 };

 struct keyring_index_key {
 	/* [!] If this structure is altered, the union in struct key must change too! */
 	unsigned long		hash;			/* Hash value */
 	union {
 		struct {
 #ifdef __LITTLE_ENDIAN /* Put desc_len at the LSB of x */
 			u16	desc_len;
 			char	desc[sizeof(long) - 2];	/* First few chars of description */
 #else
 			char	desc[sizeof(long) - 2];	/* First few chars of description */
 			u16	desc_len;
 #endif
 		};
 		unsigned long x;
 	};
 	struct key_type		*type;
 	struct key_tag		*domain_tag;	/* Domain of operation */
 	const char		*description;
 };

 union key_payload {
 	void __rcu		*rcu_data0;
 	void			*data[4];
 };

 /*****************************************************************************/
 /*
  * key reference with possession attribute handling
  *
  * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually
  * defined. This is because we abuse the bottom bit of the reference to carry a
  * flag to indicate whether the calling process possesses that key in one of
  * its keyrings.
  *
  * the key_ref_t has been made a separate type so that the compiler can reject
  * attempts to dereference it without proper conversion.
  *
  * the three functions are used to assemble and disassemble references
  */
 typedef struct __key_reference_with_attributes *key_ref_t;

 static inline key_ref_t make_key_ref(const struct key *key,
 				     bool possession)
 {
 	return (key_ref_t) ((unsigned long) key | possession);
 }

 static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)
 {
 	return (struct key *) ((unsigned long) key_ref & ~1UL);
 }

 static inline bool is_key_possessed(const key_ref_t key_ref)
 {
 	return (unsigned long) key_ref & 1UL;
 }

 typedef int (*key_restrict_link_func_t)(struct key *dest_keyring,
 					const struct key_type *type,
 					const union key_payload *payload,
 					struct key *restriction_key);

 struct key_restriction {
 	key_restrict_link_func_t check;
 	struct key *key;
 	struct key_type *keytype;
 };

 enum key_state {
 	KEY_IS_UNINSTANTIATED,
 	KEY_IS_POSITIVE,		/* Positively instantiated */
 };

 /*****************************************************************************/
 /*
  * authentication token / access credential / keyring
  * - types of key include:
  *   - keyrings
  *   - disk encryption IDs
  *   - Kerberos TGTs and tickets
  */
 struct key {
 	refcount_t		usage;		/* number of references */
 	key_serial_t		serial;		/* key serial number */
 	union {
 		struct list_head graveyard_link;
 		struct rb_node	serial_node;
 	};
 #ifdef CONFIG_KEY_NOTIFICATIONS
 	struct watch_list	*watchers;	/* Entities watching this key for changes */
 #endif
 	struct rw_semaphore	sem;		/* change vs change sem */
 	struct key_user		*user;		/* owner of this key */
 	void			*security;	/* security data for this key */
 	union {
 		time64_t	expiry;		/* time at which key expires (or 0) */
 		time64_t	revoked_at;	/* time at which key was revoked */
 	};
 	time64_t		last_used_at;	/* last time used for LRU keyring discard */
 	kuid_t			uid;
 	kgid_t			gid;
 	key_perm_t		perm;		/* access permissions */
 	unsigned short		quotalen;	/* length added to quota */
 	unsigned short		datalen;	/* payload data length
 						 * - may not match RCU dereferenced payload
 						 * - payload should contain own length
 						 */
 	short			state;		/* Key state (+) or rejection error (-) */

 #ifdef KEY_DEBUGGING
 	unsigned		magic;
 #define KEY_DEBUG_MAGIC		0x18273645u
 #endif

 	unsigned long		flags;		/* status flags (change with bitops) */
 #define KEY_FLAG_DEAD		0	/* set if key type has been deleted */
 #define KEY_FLAG_REVOKED	1	/* set if key had been revoked */
 #define KEY_FLAG_IN_QUOTA	2	/* set if key consumes quota */
 #define KEY_FLAG_USER_CONSTRUCT	3	/* set if key is being constructed in userspace */
 #define KEY_FLAG_ROOT_CAN_CLEAR	4	/* set if key can be cleared by root without permission */
 #define KEY_FLAG_INVALIDATED	5	/* set if key has been invalidated */
 #define KEY_FLAG_BUILTIN	6	/* set if key is built in to the kernel */
 #define KEY_FLAG_ROOT_CAN_INVAL	7	/* set if key can be invalidated by root without permission */
 #define KEY_FLAG_KEEP		8	/* set if key should not be removed */
 #define KEY_FLAG_UID_KEYRING	9	/* set if key is a user or user session keyring */

 	/* the key type and key description string
 	 * - the desc is used to match a key against search criteria
 	 * - it should be a printable string
 	 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
 	 */
 	union {
 		struct keyring_index_key index_key;
 		struct {
 			unsigned long	hash;
 			unsigned long	len_desc;
 			struct key_type	*type;		/* type of key */
 			struct key_tag	*domain_tag;	/* Domain of operation */
 			char		*description;
 		};
 	};

 	/* key data
 	 * - this is used to hold the data actually used in cryptography or
 	 *   whatever
 	 */
 	union {
 		union key_payload payload;
 		struct {
 			/* Keyring bits */
 			struct list_head name_link;
 			struct assoc_array keys;
 		};
 	};

 	/* This is set on a keyring to restrict the addition of a link to a key
 	 * to it.  If this structure isn't provided then it is assumed that the
 	 * keyring is open to any addition.  It is ignored for non-keyring
 	 * keys. Only set this value using keyring_restrict(), keyring_alloc(),
 	 * or key_alloc().
 	 *
 	 * This is intended for use with rings of trusted keys whereby addition
 	 * to the keyring needs to be controlled.  KEY_ALLOC_BYPASS_RESTRICTION
 	 * overrides this, allowing the kernel to add extra keys without
 	 * restriction.
 	 */
 	struct key_restriction *restrict_link;
 };

 extern struct key *key_alloc(struct key_type *type,
 			     const char *desc,
 			     kuid_t uid, kgid_t gid,
 			     const struct cred *cred,
 			     key_perm_t perm,
 			     unsigned long flags,
 			     struct key_restriction *restrict_link);


 #define KEY_ALLOC_IN_QUOTA		0x0000	/* add to quota, reject if would overrun */
 #define KEY_ALLOC_QUOTA_OVERRUN		0x0001	/* add to quota, permit even if overrun */
 #define KEY_ALLOC_NOT_IN_QUOTA		0x0002	/* not in quota */
 #define KEY_ALLOC_BUILT_IN		0x0004	/* Key is built into kernel */
 #define KEY_ALLOC_BYPASS_RESTRICTION	0x0008	/* Override the check on restricted keyrings */
 #define KEY_ALLOC_UID_KEYRING		0x0010	/* allocating a user or user session keyring */
 #define KEY_ALLOC_SET_KEEP		0x0020	/* Set the KEEP flag on the key/keyring */

 extern void key_revoke(struct key *key);
 extern void key_invalidate(struct key *key);
 extern void key_put(struct key *key);
 extern bool key_put_tag(struct key_tag *tag);
 extern void key_remove_domain(struct key_tag *domain_tag);

 static inline struct key *__key_get(struct key *key)
 {
 	refcount_inc(&key->usage);
 	return key;
 }

 static inline struct key *key_get(struct key *key)
 {
 	return key ? __key_get(key) : key;
 }

 static inline void key_ref_put(key_ref_t key_ref)
 {
 	key_put(key_ref_to_ptr(key_ref));
 }

 extern struct key *request_key_tag(struct key_type *type,
 				   const char *description,
 				   struct key_tag *domain_tag,
 				   const char *callout_info);

 extern struct key *request_key_rcu(struct key_type *type,
 				   const char *description,
 				   struct key_tag *domain_tag);

 extern struct key *request_key_with_auxdata(struct key_type *type,
 					    const char *description,
 					    struct key_tag *domain_tag,
 					    const void *callout_info,
 					    size_t callout_len,
 					    void *aux);

 /**
  * request_key - Request a key and wait for construction
  * @type: Type of key.
  * @description: The searchable description of the key.
  * @callout_info: The data to pass to the instantiation upcall (or NULL).
  *
  * As for request_key_tag(), but with the default global domain tag.
  */
 static inline struct key *request_key(struct key_type *type,
 				      const char *description,
 				      const char *callout_info)
 {
 	return request_key_tag(type, description, NULL, callout_info);
 }

 #ifdef CONFIG_NET
 /**
  * request_key_net - Request a key for a net namespace and wait for construction
  * @type: Type of key.
  * @description: The searchable description of the key.
  * @net: The network namespace that is the key's domain of operation.
  * @callout_info: The data to pass to the instantiation upcall (or NULL).
  *
  * As for request_key() except that it does not add the returned key to a
  * keyring if found, new keys are always allocated in the user's quota, the
  * callout_info must be a NUL-terminated string and no auxiliary data can be
  * passed.  Only keys that operate the specified network namespace are used.
  *
  * Furthermore, it then works as wait_for_key_construction() to wait for the
  * completion of keys undergoing construction with a non-interruptible wait.
  */
 #define request_key_net(type, description, net, callout_info) \
 	request_key_tag(type, description, net->key_domain, callout_info)

 /**
  * request_key_net_rcu - Request a key for a net namespace under RCU conditions
  * @type: Type of key.
  * @description: The searchable description of the key.
  * @net: The network namespace that is the key's domain of operation.
  *
  * As for request_key_rcu() except that only keys that operate the specified
  * network namespace are used.
  */
 #define request_key_net_rcu(type, description, net) \
 	request_key_rcu(type, description, net->key_domain)
 #endif /* CONFIG_NET */

 extern int wait_for_key_construction(struct key *key, bool intr);

 extern int key_validate(const struct key *key);

 extern key_ref_t key_create_or_update(key_ref_t keyring,
 				      const char *type,
 				      const char *description,
 				      const void *payload,
 				      size_t plen,
 				      key_perm_t perm,
 				      unsigned long flags);

 extern int key_update(key_ref_t key,
 		      const void *payload,
 		      size_t plen);

 extern int key_link(struct key *keyring,
 		    struct key *key);

 extern int key_move(struct key *key,
 		    struct key *from_keyring,
 		    struct key *to_keyring,
 		    unsigned int flags);

 extern int key_unlink(struct key *keyring,
 		      struct key *key);

 extern struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid,
 				 const struct cred *cred,
 				 key_perm_t perm,
 				 unsigned long flags,
 				 struct key_restriction *restrict_link,
 				 struct key *dest);

 extern int restrict_link_reject(struct key *keyring,
 				const struct key_type *type,
 				const union key_payload *payload,
 				struct key *restriction_key);

 extern int keyring_clear(struct key *keyring);

 extern key_ref_t keyring_search(key_ref_t keyring,
 				struct key_type *type,
 				const char *description,
 				bool recurse);

 extern int keyring_add_key(struct key *keyring,
 			   struct key *key);

 extern int keyring_restrict(key_ref_t keyring, const char *type,
 			    const char *restriction);

 extern struct key *key_lookup(key_serial_t id);

 static inline key_serial_t key_serial(const struct key *key)
 {
 	return key ? key->serial : 0;
 }

 extern void key_set_timeout(struct key *, unsigned);

 extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags,
 				 enum key_need_perm need_perm);
 extern void key_free_user_ns(struct user_namespace *);

 static inline short key_read_state(const struct key *key)
 {
 	/* Barrier versus mark_key_instantiated(). */
 	return smp_load_acquire(&key->state);
 }

 /**
  * key_is_positive - Determine if a key has been positively instantiated
  * @key: The key to check.
  *
  * Return true if the specified key has been positively instantiated, false
  * otherwise.
  */
 static inline bool key_is_positive(const struct key *key)
 {
 	return key_read_state(key) == KEY_IS_POSITIVE;
 }

 static inline bool key_is_negative(const struct key *key)
 {
 	return key_read_state(key) < 0;
 }

 #define dereference_key_rcu(KEY)					\
 	(rcu_dereference((KEY)->payload.rcu_data0))

 #define dereference_key_locked(KEY)					\
 	(rcu_dereference_protected((KEY)->payload.rcu_data0,		\
 				   rwsem_is_locked(&((struct key *)(KEY))->sem)))

 #define rcu_assign_keypointer(KEY, PAYLOAD)				\
 do {									\
 	rcu_assign_pointer((KEY)->payload.rcu_data0, (PAYLOAD));	\
 } while (0)

 #ifdef CONFIG_SYSCTL
 extern struct ctl_table key_sysctls[];
 #endif
 /*
  * the userspace interface
  */
 extern int install_thread_keyring_to_cred(struct cred *cred);
 extern void key_fsuid_changed(struct cred *new_cred);
 extern void key_fsgid_changed(struct cred *new_cred);
 extern void key_init(void);

 #else /* CONFIG_KEYS */

 #define key_validate(k)			0
 #define key_serial(k)			0
 #define key_get(k) 			({ NULL; })
 #define key_revoke(k)			do { } while(0)
 #define key_invalidate(k)		do { } while(0)
 #define key_put(k)			do { } while(0)
 #define key_ref_put(k)			do { } while(0)
 #define make_key_ref(k, p)		NULL
 #define key_ref_to_ptr(k)		NULL
 #define is_key_possessed(k)		0
 #define key_fsuid_changed(c)		do { } while(0)
 #define key_fsgid_changed(c)		do { } while(0)
 #define key_init()			do { } while(0)
 #define key_free_user_ns(ns)		do { } while(0)
 #define key_remove_domain(d)		do { } while(0)

 #endif /* CONFIG_KEYS */
 #endif /* __KERNEL__ */
 #endif /* _LINUX_KEY_H */
	/* SPDX-License-Identifier: GPL-2.0-or-later */
	/* Authentication token and access key management
	*
	* Copyright (C) 2004, 2007 Red Hat, Inc. All Rights Reserved.
	* Written by David Howells (dhowells@redhat.com)
	*
	* See Documentation/security/keys/core.rst for information on keys/keyrings.
	*/

	#ifndef _LINUX_KEY_H
	#define _LINUX_KEY_H

	#include <linux/types.h>
	#include <linux/list.h>
	#include <linux/rbtree.h>
	#include <linux/rcupdate.h>
	#include <linux/sysctl.h>
	#include <linux/rwsem.h>
	#include <linux/atomic.h>
	#include <linux/assoc_array.h>
	#include <linux/refcount.h>
	#include <linux/time64.h>

	#ifdef __KERNEL__
	#include <linux/uidgid.h>

	/* key handle serial number */
	typedef int32_t key_serial_t;

	/* key handle permissions mask */
	typedef uint32_t key_perm_t;

	struct key;
	struct net;

	#ifdef CONFIG_KEYS

	#undef KEY_DEBUGGING

	#define KEY_POS_VIEW 0x01000000 /* possessor can view a key's attributes */
	#define KEY_POS_READ 0x02000000 /* possessor can read key payload / view keyring */
	#define KEY_POS_WRITE 0x04000000 /* possessor can update key payload / add link to keyring */
	#define KEY_POS_SEARCH 0x08000000 /* possessor can find a key in search / search a keyring */
	#define KEY_POS_LINK 0x10000000 /* possessor can create a link to a key/keyring */
	#define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */
	#define KEY_POS_ALL 0x3f000000

	#define KEY_USR_VIEW 0x00010000 /* user permissions... */
	#define KEY_USR_READ 0x00020000
	#define KEY_USR_WRITE 0x00040000
	#define KEY_USR_SEARCH 0x00080000
	#define KEY_USR_LINK 0x00100000
	#define KEY_USR_SETATTR 0x00200000
	#define KEY_USR_ALL 0x003f0000

	#define KEY_GRP_VIEW 0x00000100 /* group permissions... */
	#define KEY_GRP_READ 0x00000200
	#define KEY_GRP_WRITE 0x00000400
	#define KEY_GRP_SEARCH 0x00000800
	#define KEY_GRP_LINK 0x00001000
	#define KEY_GRP_SETATTR 0x00002000
	#define KEY_GRP_ALL 0x00003f00

	#define KEY_OTH_VIEW 0x00000001 /* third party permissions... */
	#define KEY_OTH_READ 0x00000002
	#define KEY_OTH_WRITE 0x00000004
	#define KEY_OTH_SEARCH 0x00000008
	#define KEY_OTH_LINK 0x00000010
	#define KEY_OTH_SETATTR 0x00000020
	#define KEY_OTH_ALL 0x0000003f

	#define KEY_PERM_UNDEF 0xffffffff

	/*
	* The permissions required on a key that we're looking up.
	*/
	enum key_need_perm {
	KEY_NEED_UNSPECIFIED, /* Needed permission unspecified */
	KEY_NEED_VIEW, /* Require permission to view attributes */
	KEY_NEED_READ, /* Require permission to read content */
	KEY_NEED_WRITE, /* Require permission to update / modify */
	KEY_NEED_SEARCH, /* Require permission to search (keyring) or find (key) */
	KEY_NEED_LINK, /* Require permission to link */
	KEY_NEED_SETATTR, /* Require permission to change attributes */
	KEY_NEED_UNLINK, /* Require permission to unlink key */
	KEY_SYSADMIN_OVERRIDE, /* Special: override by CAP_SYS_ADMIN */
	KEY_AUTHTOKEN_OVERRIDE, /* Special: override by possession of auth token */
	KEY_DEFER_PERM_CHECK, /* Special: permission check is deferred */
	};

	struct seq_file;
	struct user_struct;
	struct signal_struct;
	struct cred;

	struct key_type;
	struct key_owner;
	struct key_tag;
	struct keyring_list;
	struct keyring_name;

	struct key_tag {
	struct rcu_head rcu;
	refcount_t usage;
	bool removed; /* T when subject removed */
	};

	struct keyring_index_key {
	/* [!] If this structure is altered, the union in struct key must change too! */
	unsigned long hash; /* Hash value */
	union {
	struct {
	#ifdef __LITTLE_ENDIAN /* Put desc_len at the LSB of x */
	u16 desc_len;
	char desc[sizeof(long) - 2]; /* First few chars of description */
	#else
	char desc[sizeof(long) - 2]; /* First few chars of description */
	u16 desc_len;
	#endif
	};
	unsigned long x;
	};
	struct key_type *type;
	struct key_tag domain_tag; / Domain of operation */
	const char *description;
	};

	union key_payload {
	void __rcu *rcu_data0;
	void *data[4];
	};

	/*****************************************************************************/
	/*
	* key reference with possession attribute handling
	*
	* NOTE! key_ref_t is a typedef'd pointer to a type that is not actually
	* defined. This is because we abuse the bottom bit of the reference to carry a
	* flag to indicate whether the calling process possesses that key in one of
	* its keyrings.
	*
	* the key_ref_t has been made a separate type so that the compiler can reject
	* attempts to dereference it without proper conversion.
	*
	* the three functions are used to assemble and disassemble references
	*/
	typedef struct __key_reference_with_attributes *key_ref_t;

	static inline key_ref_t make_key_ref(const struct key *key,
	bool possession)
	{
	return (key_ref_t) ((unsigned long) key \| possession);
	}

	static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)
	{
	return (struct key *) ((unsigned long) key_ref & ~1UL);
	}

	static inline bool is_key_possessed(const key_ref_t key_ref)
	{
	return (unsigned long) key_ref & 1UL;
	}

	typedef int (key_restrict_link_func_t)(struct key dest_keyring,
	const struct key_type *type,
	const union key_payload *payload,
	struct key *restriction_key);

	struct key_restriction {
	key_restrict_link_func_t check;
	struct key *key;
	struct key_type *keytype;
	};

	enum key_state {
	KEY_IS_UNINSTANTIATED,
	KEY_IS_POSITIVE, /* Positively instantiated */
	};

	/*****************************************************************************/
	/*
	* authentication token / access credential / keyring
	* - types of key include:
	* - keyrings
	* - disk encryption IDs
	* - Kerberos TGTs and tickets
	*/
	struct key {
	refcount_t usage; /* number of references */
	key_serial_t serial; /* key serial number */
	union {
	struct list_head graveyard_link;
	struct rb_node serial_node;
	};
	#ifdef CONFIG_KEY_NOTIFICATIONS
	struct watch_list watchers; / Entities watching this key for changes */
	#endif
	struct rw_semaphore sem; /* change vs change sem */
	struct key_user user; / owner of this key */
	void security; / security data for this key */
	union {
	time64_t expiry; /* time at which key expires (or 0) */
	time64_t revoked_at; /* time at which key was revoked */
	};
	time64_t last_used_at; /* last time used for LRU keyring discard */
	kuid_t uid;
	kgid_t gid;
	key_perm_t perm; /* access permissions */
	unsigned short quotalen; /* length added to quota */
	unsigned short datalen; /* payload data length
	* - may not match RCU dereferenced payload
	* - payload should contain own length
	*/
	short state; /* Key state (+) or rejection error (-) */

	#ifdef KEY_DEBUGGING
	unsigned magic;
	#define KEY_DEBUG_MAGIC 0x18273645u
	#endif

	unsigned long flags; /* status flags (change with bitops) */
	#define KEY_FLAG_DEAD 0 /* set if key type has been deleted */
	#define KEY_FLAG_REVOKED 1 /* set if key had been revoked */
	#define KEY_FLAG_IN_QUOTA 2 /* set if key consumes quota */
	#define KEY_FLAG_USER_CONSTRUCT 3 /* set if key is being constructed in userspace */
	#define KEY_FLAG_ROOT_CAN_CLEAR 4 /* set if key can be cleared by root without permission */
	#define KEY_FLAG_INVALIDATED 5 /* set if key has been invalidated */
	#define KEY_FLAG_BUILTIN 6 /* set if key is built in to the kernel */
	#define KEY_FLAG_ROOT_CAN_INVAL 7 /* set if key can be invalidated by root without permission */
	#define KEY_FLAG_KEEP 8 /* set if key should not be removed */
	#define KEY_FLAG_UID_KEYRING 9 /* set if key is a user or user session keyring */

	/* the key type and key description string
	* - the desc is used to match a key against search criteria
	* - it should be a printable string
	* - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
	*/
	union {
	struct keyring_index_key index_key;
	struct {
	unsigned long hash;
	unsigned long len_desc;
	struct key_type type; / type of key */
	struct key_tag domain_tag; / Domain of operation */
	char *description;
	};
	};

	/* key data
	* - this is used to hold the data actually used in cryptography or
	* whatever
	*/
	union {
	union key_payload payload;
	struct {
	/* Keyring bits */
	struct list_head name_link;
	struct assoc_array keys;
	};
	};

	/* This is set on a keyring to restrict the addition of a link to a key
	* to it. If this structure isn't provided then it is assumed that the
	* keyring is open to any addition. It is ignored for non-keyring
	* keys. Only set this value using keyring_restrict(), keyring_alloc(),
	* or key_alloc().
	*
	* This is intended for use with rings of trusted keys whereby addition
	* to the keyring needs to be controlled. KEY_ALLOC_BYPASS_RESTRICTION
	* overrides this, allowing the kernel to add extra keys without
	* restriction.
	*/
	struct key_restriction *restrict_link;
	};

	extern struct key key_alloc(struct key_type type,
	const char *desc,
	kuid_t uid, kgid_t gid,
	const struct cred *cred,
	key_perm_t perm,
	unsigned long flags,
	struct key_restriction *restrict_link);


	#define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */
	#define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */
	#define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */
	#define KEY_ALLOC_BUILT_IN 0x0004 /* Key is built into kernel */
	#define KEY_ALLOC_BYPASS_RESTRICTION 0x0008 /* Override the check on restricted keyrings */
	#define KEY_ALLOC_UID_KEYRING 0x0010 /* allocating a user or user session keyring */
	#define KEY_ALLOC_SET_KEEP 0x0020 /* Set the KEEP flag on the key/keyring */

	extern void key_revoke(struct key *key);
	extern void key_invalidate(struct key *key);
	extern void key_put(struct key *key);
	extern bool key_put_tag(struct key_tag *tag);
	extern void key_remove_domain(struct key_tag *domain_tag);

	static inline struct key __key_get(struct key key)
	{
	refcount_inc(&key->usage);
	return key;
	}

	static inline struct key key_get(struct key key)
	{
	return key ? __key_get(key) : key;
	}

	static inline void key_ref_put(key_ref_t key_ref)
	{
	key_put(key_ref_to_ptr(key_ref));
	}

	extern struct key request_key_tag(struct key_type type,
	const char *description,
	struct key_tag *domain_tag,
	const char *callout_info);

	extern struct key request_key_rcu(struct key_type type,
	const char *description,
	struct key_tag *domain_tag);

	extern struct key request_key_with_auxdata(struct key_type type,
	const char *description,
	struct key_tag *domain_tag,
	const void *callout_info,
	size_t callout_len,
	void *aux);

	/**
	* request_key - Request a key and wait for construction
	* @type: Type of key.
	* @description: The searchable description of the key.
	* @callout_info: The data to pass to the instantiation upcall (or NULL).
	*
	* As for request_key_tag(), but with the default global domain tag.
	*/
	static inline struct key request_key(struct key_type type,
	const char *description,
	const char *callout_info)
	{
	return request_key_tag(type, description, NULL, callout_info);
	}

	#ifdef CONFIG_NET
	/**
	* request_key_net - Request a key for a net namespace and wait for construction
	* @type: Type of key.
	* @description: The searchable description of the key.
	* @net: The network namespace that is the key's domain of operation.
	* @callout_info: The data to pass to the instantiation upcall (or NULL).
	*
	* As for request_key() except that it does not add the returned key to a
	* keyring if found, new keys are always allocated in the user's quota, the
	* callout_info must be a NUL-terminated string and no auxiliary data can be
	* passed. Only keys that operate the specified network namespace are used.
	*
	* Furthermore, it then works as wait_for_key_construction() to wait for the
	* completion of keys undergoing construction with a non-interruptible wait.
	*/
	#define request_key_net(type, description, net, callout_info) \
	request_key_tag(type, description, net->key_domain, callout_info)

	/**
	* request_key_net_rcu - Request a key for a net namespace under RCU conditions
	* @type: Type of key.
	* @description: The searchable description of the key.
	* @net: The network namespace that is the key's domain of operation.
	*
	* As for request_key_rcu() except that only keys that operate the specified
	* network namespace are used.
	*/
	#define request_key_net_rcu(type, description, net) \
	request_key_rcu(type, description, net->key_domain)
	#endif /* CONFIG_NET */

	extern int wait_for_key_construction(struct key *key, bool intr);

	extern int key_validate(const struct key *key);

	extern key_ref_t key_create_or_update(key_ref_t keyring,
	const char *type,
	const char *description,
	const void *payload,
	size_t plen,
	key_perm_t perm,
	unsigned long flags);

	extern int key_update(key_ref_t key,
	const void *payload,
	size_t plen);

	extern int key_link(struct key *keyring,
	struct key *key);

	extern int key_move(struct key *key,
	struct key *from_keyring,
	struct key *to_keyring,
	unsigned int flags);

	extern int key_unlink(struct key *keyring,
	struct key *key);

	extern struct key keyring_alloc(const char description, kuid_t uid, kgid_t gid,
	const struct cred *cred,
	key_perm_t perm,
	unsigned long flags,
	struct key_restriction *restrict_link,
	struct key *dest);

	extern int restrict_link_reject(struct key *keyring,
	const struct key_type *type,
	const union key_payload *payload,
	struct key *restriction_key);

	extern int keyring_clear(struct key *keyring);

	extern key_ref_t keyring_search(key_ref_t keyring,
	struct key_type *type,
	const char *description,
	bool recurse);

	extern int keyring_add_key(struct key *keyring,
	struct key *key);

	extern int keyring_restrict(key_ref_t keyring, const char *type,
	const char *restriction);

	extern struct key *key_lookup(key_serial_t id);

	static inline key_serial_t key_serial(const struct key *key)
	{
	return key ? key->serial : 0;
	}

	extern void key_set_timeout(struct key *, unsigned);

	extern key_ref_t lookup_user_key(key_serial_t id, unsigned long flags,
	enum key_need_perm need_perm);
	extern void key_free_user_ns(struct user_namespace *);

	static inline short key_read_state(const struct key *key)
	{
	/* Barrier versus mark_key_instantiated(). */
	return smp_load_acquire(&key->state);
	}

	/**
	* key_is_positive - Determine if a key has been positively instantiated
	* @key: The key to check.
	*
	* Return true if the specified key has been positively instantiated, false
	* otherwise.
	*/
	static inline bool key_is_positive(const struct key *key)
	{
	return key_read_state(key) == KEY_IS_POSITIVE;
	}

	static inline bool key_is_negative(const struct key *key)
	{
	return key_read_state(key) < 0;
	}

	#define dereference_key_rcu(KEY) \
	(rcu_dereference((KEY)->payload.rcu_data0))

	#define dereference_key_locked(KEY) \
	(rcu_dereference_protected((KEY)->payload.rcu_data0, \
	rwsem_is_locked(&((struct key *)(KEY))->sem)))

	#define rcu_assign_keypointer(KEY, PAYLOAD) \
	do { \
	rcu_assign_pointer((KEY)->payload.rcu_data0, (PAYLOAD)); \
	} while (0)

	#ifdef CONFIG_SYSCTL
	extern struct ctl_table key_sysctls[];
	#endif
	/*
	* the userspace interface
	*/
	extern int install_thread_keyring_to_cred(struct cred *cred);
	extern void key_fsuid_changed(struct cred *new_cred);
	extern void key_fsgid_changed(struct cred *new_cred);
	extern void key_init(void);

	#else /* CONFIG_KEYS */

	#define key_validate(k) 0
	#define key_serial(k) 0
	#define key_get(k) ({ NULL; })
	#define key_revoke(k) do { } while(0)
	#define key_invalidate(k) do { } while(0)
	#define key_put(k) do { } while(0)
	#define key_ref_put(k) do { } while(0)
	#define make_key_ref(k, p) NULL
	#define key_ref_to_ptr(k) NULL
	#define is_key_possessed(k) 0
	#define key_fsuid_changed(c) do { } while(0)
	#define key_fsgid_changed(c) do { } while(0)
	#define key_init() do { } while(0)
	#define key_free_user_ns(ns) do { } while(0)
	#define key_remove_domain(d) do { } while(0)

	#endif /* CONFIG_KEYS */
	#endif /* __KERNEL__ */
	#endif /* _LINUX_KEY_H */