310 lines
		
	
	
		
			8.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			310 lines
		
	
	
		
			8.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* Authentication token and access key management
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 *
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 * Copyright (C) 2004, 2007 Red Hat, Inc. All Rights Reserved.
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 * Written by David Howells (dhowells@redhat.com)
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 *
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 * This program is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU General Public License
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 * as published by the Free Software Foundation; either version
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 * 2 of the License, or (at your option) any later version.
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 *
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 *
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 * See Documentation/keys.txt for information on keys/keyrings.
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 */
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#ifndef _LINUX_KEY_H
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#define _LINUX_KEY_H
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/rbtree.h>
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#include <linux/rcupdate.h>
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#include <linux/sysctl.h>
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#include <linux/rwsem.h>
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#include <asm/atomic.h>
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#ifdef __KERNEL__
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/* key handle serial number */
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typedef int32_t key_serial_t;
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/* key handle permissions mask */
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typedef uint32_t key_perm_t;
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struct key;
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#ifdef CONFIG_KEYS
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#undef KEY_DEBUGGING
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#define KEY_POS_VIEW	0x01000000	/* possessor can view a key's attributes */
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#define KEY_POS_READ	0x02000000	/* possessor can read key payload / view keyring */
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#define KEY_POS_WRITE	0x04000000	/* possessor can update key payload / add link to keyring */
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#define KEY_POS_SEARCH	0x08000000	/* possessor can find a key in search / search a keyring */
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#define KEY_POS_LINK	0x10000000	/* possessor can create a link to a key/keyring */
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#define KEY_POS_SETATTR	0x20000000	/* possessor can set key attributes */
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#define KEY_POS_ALL	0x3f000000
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#define KEY_USR_VIEW	0x00010000	/* user permissions... */
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#define KEY_USR_READ	0x00020000
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#define KEY_USR_WRITE	0x00040000
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#define KEY_USR_SEARCH	0x00080000
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#define KEY_USR_LINK	0x00100000
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#define KEY_USR_SETATTR	0x00200000
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#define KEY_USR_ALL	0x003f0000
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#define KEY_GRP_VIEW	0x00000100	/* group permissions... */
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#define KEY_GRP_READ	0x00000200
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#define KEY_GRP_WRITE	0x00000400
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#define KEY_GRP_SEARCH	0x00000800
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#define KEY_GRP_LINK	0x00001000
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#define KEY_GRP_SETATTR	0x00002000
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#define KEY_GRP_ALL	0x00003f00
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#define KEY_OTH_VIEW	0x00000001	/* third party permissions... */
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#define KEY_OTH_READ	0x00000002
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#define KEY_OTH_WRITE	0x00000004
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#define KEY_OTH_SEARCH	0x00000008
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#define KEY_OTH_LINK	0x00000010
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#define KEY_OTH_SETATTR	0x00000020
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#define KEY_OTH_ALL	0x0000003f
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#define KEY_PERM_UNDEF	0xffffffff
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struct seq_file;
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struct user_struct;
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struct signal_struct;
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struct cred;
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struct key_type;
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struct key_owner;
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struct keyring_list;
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struct keyring_name;
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/*****************************************************************************/
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/*
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 * key reference with possession attribute handling
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 *
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 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually
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 * defined. This is because we abuse the bottom bit of the reference to carry a
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 * flag to indicate whether the calling process possesses that key in one of
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 * its keyrings.
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 *
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 * the key_ref_t has been made a separate type so that the compiler can reject
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 * attempts to dereference it without proper conversion.
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 *
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 * the three functions are used to assemble and disassemble references
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 */
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typedef struct __key_reference_with_attributes *key_ref_t;
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static inline key_ref_t make_key_ref(const struct key *key,
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				     unsigned long possession)
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{
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	return (key_ref_t) ((unsigned long) key | possession);
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}
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static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)
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{
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	return (struct key *) ((unsigned long) key_ref & ~1UL);
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}
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static inline unsigned long is_key_possessed(const key_ref_t key_ref)
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{
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	return (unsigned long) key_ref & 1UL;
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}
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/*****************************************************************************/
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/*
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 * authentication token / access credential / keyring
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 * - types of key include:
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 *   - keyrings
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 *   - disk encryption IDs
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 *   - Kerberos TGTs and tickets
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 */
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struct key {
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	atomic_t		usage;		/* number of references */
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	key_serial_t		serial;		/* key serial number */
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	struct rb_node		serial_node;
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	struct key_type		*type;		/* type of key */
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	struct rw_semaphore	sem;		/* change vs change sem */
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	struct key_user		*user;		/* owner of this key */
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	void			*security;	/* security data for this key */
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	union {
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		time_t		expiry;		/* time at which key expires (or 0) */
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		time_t		revoked_at;	/* time at which key was revoked */
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	};
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	uid_t			uid;
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	gid_t			gid;
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	key_perm_t		perm;		/* access permissions */
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	unsigned short		quotalen;	/* length added to quota */
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	unsigned short		datalen;	/* payload data length
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						 * - may not match RCU dereferenced payload
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						 * - payload should contain own length
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						 */
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#ifdef KEY_DEBUGGING
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	unsigned		magic;
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#define KEY_DEBUG_MAGIC		0x18273645u
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#define KEY_DEBUG_MAGIC_X	0xf8e9dacbu
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#endif
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	unsigned long		flags;		/* status flags (change with bitops) */
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#define KEY_FLAG_INSTANTIATED	0	/* set if key has been instantiated */
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#define KEY_FLAG_DEAD		1	/* set if key type has been deleted */
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#define KEY_FLAG_REVOKED	2	/* set if key had been revoked */
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#define KEY_FLAG_IN_QUOTA	3	/* set if key consumes quota */
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#define KEY_FLAG_USER_CONSTRUCT	4	/* set if key is being constructed in userspace */
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#define KEY_FLAG_NEGATIVE	5	/* set if key is negative */
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	/* the description string
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	 * - this is used to match a key against search criteria
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	 * - this should be a printable string
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	 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
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	 */
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	char			*description;
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	/* type specific data
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	 * - this is used by the keyring type to index the name
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	 */
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	union {
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		struct list_head	link;
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		unsigned long		x[2];
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		void			*p[2];
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	} type_data;
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	/* key data
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	 * - this is used to hold the data actually used in cryptography or
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	 *   whatever
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	 */
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	union {
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		unsigned long		value;
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		void			*data;
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		struct keyring_list	*subscriptions;
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	} payload;
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};
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extern struct key *key_alloc(struct key_type *type,
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			     const char *desc,
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			     uid_t uid, gid_t gid,
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			     const struct cred *cred,
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			     key_perm_t perm,
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			     unsigned long flags);
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#define KEY_ALLOC_IN_QUOTA	0x0000	/* add to quota, reject if would overrun */
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#define KEY_ALLOC_QUOTA_OVERRUN	0x0001	/* add to quota, permit even if overrun */
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#define KEY_ALLOC_NOT_IN_QUOTA	0x0002	/* not in quota */
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extern void key_revoke(struct key *key);
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extern void key_put(struct key *key);
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static inline struct key *key_get(struct key *key)
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{
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	if (key)
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		atomic_inc(&key->usage);
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	return key;
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}
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static inline void key_ref_put(key_ref_t key_ref)
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{
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	key_put(key_ref_to_ptr(key_ref));
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}
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extern struct key *request_key(struct key_type *type,
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			       const char *description,
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			       const char *callout_info);
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extern struct key *request_key_with_auxdata(struct key_type *type,
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					    const char *description,
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					    const void *callout_info,
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					    size_t callout_len,
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					    void *aux);
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extern struct key *request_key_async(struct key_type *type,
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				     const char *description,
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				     const void *callout_info,
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				     size_t callout_len);
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extern struct key *request_key_async_with_auxdata(struct key_type *type,
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						  const char *description,
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						  const void *callout_info,
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						  size_t callout_len,
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						  void *aux);
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extern int wait_for_key_construction(struct key *key, bool intr);
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extern int key_validate(struct key *key);
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extern key_ref_t key_create_or_update(key_ref_t keyring,
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				      const char *type,
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				      const char *description,
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				      const void *payload,
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				      size_t plen,
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				      key_perm_t perm,
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				      unsigned long flags);
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extern int key_update(key_ref_t key,
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		      const void *payload,
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		      size_t plen);
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extern int key_link(struct key *keyring,
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		    struct key *key);
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extern int key_unlink(struct key *keyring,
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		      struct key *key);
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extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
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				 const struct cred *cred,
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				 unsigned long flags,
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				 struct key *dest);
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extern int keyring_clear(struct key *keyring);
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extern key_ref_t keyring_search(key_ref_t keyring,
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				struct key_type *type,
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				const char *description);
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extern int keyring_add_key(struct key *keyring,
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			   struct key *key);
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extern struct key *key_lookup(key_serial_t id);
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static inline key_serial_t key_serial(struct key *key)
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{
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	return key ? key->serial : 0;
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}
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#ifdef CONFIG_SYSCTL
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extern ctl_table key_sysctls[];
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#endif
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extern void key_replace_session_keyring(void);
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/*
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 * the userspace interface
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 */
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extern int install_thread_keyring_to_cred(struct cred *cred);
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extern void key_fsuid_changed(struct task_struct *tsk);
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extern void key_fsgid_changed(struct task_struct *tsk);
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extern void key_init(void);
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#else /* CONFIG_KEYS */
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#define key_validate(k)			0
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#define key_serial(k)			0
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#define key_get(k) 			({ NULL; })
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#define key_revoke(k)			do { } while(0)
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#define key_put(k)			do { } while(0)
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#define key_ref_put(k)			do { } while(0)
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#define make_key_ref(k, p)		NULL
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#define key_ref_to_ptr(k)		NULL
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#define is_key_possessed(k)		0
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#define key_fsuid_changed(t)		do { } while(0)
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#define key_fsgid_changed(t)		do { } while(0)
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#define key_init()			do { } while(0)
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#define key_replace_session_keyring()	do { } while(0)
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#endif /* CONFIG_KEYS */
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#endif /* __KERNEL__ */
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#endif /* _LINUX_KEY_H */
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