304 lines
9.2 KiB
C
304 lines
9.2 KiB
C
/* key.h: authentication token and access key management
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*
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* Copyright (C) 2004 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 <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_USR_VIEW 0x00010000 /* user can view a key's attributes */
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#define KEY_USR_READ 0x00020000 /* user can read key payload / view keyring */
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#define KEY_USR_WRITE 0x00040000 /* user can update key payload / add link to keyring */
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#define KEY_USR_SEARCH 0x00080000 /* user can find a key in search / search a keyring */
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#define KEY_USR_LINK 0x00100000 /* user can create a link to a key/keyring */
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#define KEY_USR_ALL 0x001f0000
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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_ALL 0x00001f00
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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_ALL 0x0000001f
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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 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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* 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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time_t expiry; /* time at which key expires (or 0) */
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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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} 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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/*****************************************************************************/
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/*
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* kernel managed key type definition
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*/
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struct key_type {
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/* name of the type */
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const char *name;
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/* default payload length for quota precalculation (optional)
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* - this can be used instead of calling key_payload_reserve(), that
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* function only needs to be called if the real datalen is different
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*/
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size_t def_datalen;
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/* instantiate a key of this type
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* - this method should call key_payload_reserve() to determine if the
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* user's quota will hold the payload
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*/
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int (*instantiate)(struct key *key, const void *data, size_t datalen);
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/* duplicate a key of this type (optional)
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* - the source key will be locked against change
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* - the new description will be attached
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* - the quota will have been adjusted automatically from
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* source->quotalen
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*/
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int (*duplicate)(struct key *key, const struct key *source);
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/* update a key of this type (optional)
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* - this method should call key_payload_reserve() to recalculate the
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* quota consumption
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* - the key must be locked against read when modifying
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*/
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int (*update)(struct key *key, const void *data, size_t datalen);
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/* match a key against a description */
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int (*match)(const struct key *key, const void *desc);
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/* clear the data from a key (optional) */
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void (*destroy)(struct key *key);
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/* describe a key */
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void (*describe)(const struct key *key, struct seq_file *p);
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/* read a key's data (optional)
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* - permission checks will be done by the caller
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* - the key's semaphore will be readlocked by the caller
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* - should return the amount of data that could be read, no matter how
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* much is copied into the buffer
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* - shouldn't do the copy if the buffer is NULL
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*/
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long (*read)(const struct key *key, char __user *buffer, size_t buflen);
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/* internal fields */
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struct list_head link; /* link in types list */
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};
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extern struct key_type key_type_keyring;
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extern int register_key_type(struct key_type *ktype);
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extern void unregister_key_type(struct key_type *ktype);
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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, key_perm_t perm,
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int not_in_quota);
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extern int key_payload_reserve(struct key *key, size_t datalen);
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extern int key_instantiate_and_link(struct key *key,
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const void *data,
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size_t datalen,
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struct key *keyring,
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struct key *instkey);
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extern int key_negate_and_link(struct key *key,
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unsigned timeout,
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struct key *keyring,
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struct key *instkey);
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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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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 int key_validate(struct key *key);
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extern struct key *key_create_or_update(struct key *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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int not_in_quota);
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extern int key_update(struct key *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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int not_in_quota, struct key *dest);
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extern int keyring_clear(struct key *keyring);
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extern struct key *keyring_search(struct key *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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extern void keyring_replace_payload(struct key *key, void *replacement);
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#define key_serial(key) ((key) ? (key)->serial : 0)
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/*
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* the userspace interface
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*/
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extern struct key root_user_keyring, root_session_keyring;
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extern int alloc_uid_keyring(struct user_struct *user);
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extern void switch_uid_keyring(struct user_struct *new_user);
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extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk);
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extern int copy_thread_group_keys(struct task_struct *tsk);
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extern void exit_keys(struct task_struct *tsk);
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extern void exit_thread_group_keys(struct signal_struct *tg);
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extern int suid_keys(struct task_struct *tsk);
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extern int exec_keys(struct task_struct *tsk);
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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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#define __install_session_keyring(tsk, keyring) \
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({ \
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struct key *old_session = tsk->signal->session_keyring; \
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tsk->signal->session_keyring = keyring; \
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old_session; \
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})
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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_put(k) do { } while(0)
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#define alloc_uid_keyring(u) 0
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#define switch_uid_keyring(u) do { } while(0)
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#define __install_session_keyring(t, k) ({ NULL; })
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#define copy_keys(f,t) 0
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#define copy_thread_group_keys(t) 0
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#define exit_keys(t) do { } while(0)
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#define exit_thread_group_keys(tg) do { } while(0)
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#define suid_keys(t) do { } while(0)
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#define exec_keys(t) do { } while(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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#endif /* CONFIG_KEYS */
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#endif /* __KERNEL__ */
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#endif /* _LINUX_KEY_H */
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