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diff --git a/include/linux/key.h b/include/linux/key.h
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+/* key.h: authentication token and access key management
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ *
+ * See Documentation/keys.txt 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/spinlock.h>
+#include <asm/atomic.h>
+
+#ifdef __KERNEL__
+
+/* key handle serial number */
+typedef int32_t key_serial_t;
+
+/* key handle permissions mask */
+typedef uint32_t key_perm_t;
+
+struct key;
+
+#ifdef CONFIG_KEYS
+
+#undef KEY_DEBUGGING
+
+#define KEY_USR_VIEW 0x00010000 /* user can view a key's attributes */
+#define KEY_USR_READ 0x00020000 /* user can read key payload / view keyring */
+#define KEY_USR_WRITE 0x00040000 /* user can update key payload / add link to keyring */
+#define KEY_USR_SEARCH 0x00080000 /* user can find a key in search / search a keyring */
+#define KEY_USR_LINK 0x00100000 /* user can create a link to a key/keyring */
+#define KEY_USR_ALL 0x001f0000
+
+#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_ALL 0x00001f00
+
+#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_ALL 0x0000001f
+
+struct seq_file;
+struct user_struct;
+struct signal_struct;
+
+struct key_type;
+struct key_owner;
+struct keyring_list;
+struct keyring_name;
+
+/*****************************************************************************/
+/*
+ * authentication token / access credential / keyring
+ * - types of key include:
+ * - keyrings
+ * - disk encryption IDs
+ * - Kerberos TGTs and tickets
+ */
+struct key {
+ atomic_t usage; /* number of references */
+ key_serial_t serial; /* key serial number */
+ struct rb_node serial_node;
+ struct key_type *type; /* type of key */
+ rwlock_t lock; /* examination vs change lock */
+ struct rw_semaphore sem; /* change vs change sem */
+ struct key_user *user; /* owner of this key */
+ time_t expiry; /* time at which key expires (or 0) */
+ uid_t uid;
+ gid_t gid;
+ key_perm_t perm; /* access permissions */
+ unsigned short quotalen; /* length added to quota */
+ unsigned short datalen; /* payload data length */
+ unsigned short flags; /* status flags (change with lock writelocked) */
+#define KEY_FLAG_INSTANTIATED 0x00000001 /* set if key has been instantiated */
+#define KEY_FLAG_DEAD 0x00000002 /* set if key type has been deleted */
+#define KEY_FLAG_REVOKED 0x00000004 /* set if key had been revoked */
+#define KEY_FLAG_IN_QUOTA 0x00000008 /* set if key consumes quota */
+#define KEY_FLAG_USER_CONSTRUCT 0x00000010 /* set if key is being constructed in userspace */
+#define KEY_FLAG_NEGATIVE 0x00000020 /* set if key is negative */
+
+#ifdef KEY_DEBUGGING
+ unsigned magic;
+#define KEY_DEBUG_MAGIC 0x18273645u
+#define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
+#endif
+
+ /* the description string
+ * - this is used to match a key against search criteria
+ * - this should be a printable string
+ * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
+ */
+ char *description;
+
+ /* type specific data
+ * - this is used by the keyring type to index the name
+ */
+ union {
+ struct list_head link;
+ } type_data;
+
+ /* key data
+ * - this is used to hold the data actually used in cryptography or
+ * whatever
+ */
+ union {
+ unsigned long value;
+ void *data;
+ struct keyring_list *subscriptions;
+ } payload;
+};
+
+/*****************************************************************************/
+/*
+ * kernel managed key type definition
+ */
+struct key_type {
+ /* name of the type */
+ const char *name;
+
+ /* default payload length for quota precalculation (optional)
+ * - this can be used instead of calling key_payload_reserve(), that
+ * function only needs to be called if the real datalen is different
+ */
+ size_t def_datalen;
+
+ /* instantiate a key of this type
+ * - this method should call key_payload_reserve() to determine if the
+ * user's quota will hold the payload
+ */
+ int (*instantiate)(struct key *key, const void *data, size_t datalen);
+
+ /* duplicate a key of this type (optional)
+ * - the source key will be locked against change
+ * - the new description will be attached
+ * - the quota will have been adjusted automatically from
+ * source->quotalen
+ */
+ int (*duplicate)(struct key *key, const struct key *source);
+
+ /* update a key of this type (optional)
+ * - this method should call key_payload_reserve() to recalculate the
+ * quota consumption
+ * - the key must be locked against read when modifying
+ */
+ int (*update)(struct key *key, const void *data, size_t datalen);
+
+ /* match a key against a description */
+ int (*match)(const struct key *key, const void *desc);
+
+ /* clear the data from a key (optional) */
+ void (*destroy)(struct key *key);
+
+ /* describe a key */
+ void (*describe)(const struct key *key, struct seq_file *p);
+
+ /* read a key's data (optional)
+ * - permission checks will be done by the caller
+ * - the key's semaphore will be readlocked by the caller
+ * - should return the amount of data that could be read, no matter how
+ * much is copied into the buffer
+ * - shouldn't do the copy if the buffer is NULL
+ */
+ long (*read)(const struct key *key, char __user *buffer, size_t buflen);
+
+ /* internal fields */
+ struct list_head link; /* link in types list */
+};
+
+extern struct key_type key_type_keyring;
+
+extern int register_key_type(struct key_type *ktype);
+extern void unregister_key_type(struct key_type *ktype);
+
+extern struct key *key_alloc(struct key_type *type,
+ const char *desc,
+ uid_t uid, gid_t gid, key_perm_t perm,
+ int not_in_quota);
+extern int key_payload_reserve(struct key *key, size_t datalen);
+extern int key_instantiate_and_link(struct key *key,
+ const void *data,
+ size_t datalen,
+ struct key *keyring);
+extern int key_negate_and_link(struct key *key,
+ unsigned timeout,
+ struct key *keyring);
+extern void key_revoke(struct key *key);
+extern void key_put(struct key *key);
+
+static inline struct key *key_get(struct key *key)
+{
+ if (key)
+ atomic_inc(&key->usage);
+ return key;
+}
+
+extern struct key *request_key(struct key_type *type,
+ const char *description,
+ const char *callout_info);
+
+extern int key_validate(struct key *key);
+
+extern struct key *key_create_or_update(struct key *keyring,
+ const char *type,
+ const char *description,
+ const void *payload,
+ size_t plen,
+ int not_in_quota);
+
+extern int key_update(struct key *key,
+ const void *payload,
+ size_t plen);
+
+extern int key_link(struct key *keyring,
+ struct key *key);
+
+extern int key_unlink(struct key *keyring,
+ struct key *key);
+
+extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
+ int not_in_quota, struct key *dest);
+
+extern int keyring_clear(struct key *keyring);
+
+extern struct key *keyring_search(struct key *keyring,
+ struct key_type *type,
+ const char *description);
+
+extern struct key *search_process_keyrings(struct key_type *type,
+ const char *description);
+
+extern int keyring_add_key(struct key *keyring,
+ struct key *key);
+
+extern struct key *key_lookup(key_serial_t id);
+
+#define key_serial(key) ((key) ? (key)->serial : 0)
+
+/*
+ * the userspace interface
+ */
+extern struct key root_user_keyring, root_session_keyring;
+extern int alloc_uid_keyring(struct user_struct *user);
+extern void switch_uid_keyring(struct user_struct *new_user);
+extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk);
+extern int copy_thread_group_keys(struct task_struct *tsk);
+extern void exit_keys(struct task_struct *tsk);
+extern void exit_thread_group_keys(struct signal_struct *tg);
+extern int suid_keys(struct task_struct *tsk);
+extern int exec_keys(struct task_struct *tsk);
+extern void key_fsuid_changed(struct task_struct *tsk);
+extern void key_fsgid_changed(struct task_struct *tsk);
+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_put(k) do { } while(0)
+#define alloc_uid_keyring(u) 0
+#define switch_uid_keyring(u) do { } while(0)
+#define copy_keys(f,t) 0
+#define copy_thread_group_keys(t) 0
+#define exit_keys(t) do { } while(0)
+#define exit_thread_group_keys(tg) do { } while(0)
+#define suid_keys(t) do { } while(0)
+#define exec_keys(t) do { } while(0)
+#define key_fsuid_changed(t) do { } while(0)
+#define key_fsgid_changed(t) do { } while(0)
+#define key_init() do { } while(0)
+
+#endif /* CONFIG_KEYS */
+#endif /* __KERNEL__ */
+#endif /* _LINUX_KEY_H */