329 строки
9.4 KiB
C
329 строки
9.4 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/security/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 <linux/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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int reject_error;
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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 __rcu *rcudata;
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void *data;
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struct keyring_list __rcu *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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/**
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* key_is_instantiated - Determine if a key has been positively instantiated
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* @key: The key to check.
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*
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* Return true if the specified key has been positively instantiated, false
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* otherwise.
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*/
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static inline bool key_is_instantiated(const struct key *key)
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{
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return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) &&
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!test_bit(KEY_FLAG_NEGATIVE, &key->flags);
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}
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#define rcu_dereference_key(KEY) \
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(rcu_dereference_protected((KEY)->payload.rcudata, \
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rwsem_is_locked(&((struct key *)(KEY))->sem)))
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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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