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kernel/include/linux/key.h
David Howells 7318226ea2 [AF_RXRPC]: Key facility changes for AF_RXRPC 
Export the keyring key type definition and document its availability.

Add alternative types into the key's type_data union to make it more useful.
Not all users necessarily want to use it as a list_head (AF_RXRPC doesn't, for
example), so make it clear that it can be used in other ways.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-04-26 15:46:23 -07:00

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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/rcupdate.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_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
struct seq_file;
struct user_struct;
struct signal_struct;
struct key_type;
struct key_owner;
struct keyring_list;
struct keyring_name;
/*****************************************************************************/
/*
* 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,
unsigned long 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 unsigned long is_key_possessed(const key_ref_t key_ref)
{
return (unsigned long) key_ref & 1UL;
}
/*****************************************************************************/
/*
* 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 */
struct rw_semaphore sem; /* change vs change sem */
struct key_user *user; /* owner of this key */
void *security; /* security data for 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
* - may not match RCU dereferenced payload
* - payload should contain own length
*/
#ifdef KEY_DEBUGGING
unsigned magic;
#define KEY_DEBUG_MAGIC 0x18273645u
#define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
#endif
unsigned long flags; /* status flags (change with bitops) */
#define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */
#define KEY_FLAG_DEAD 1 /* set if key type has been deleted */
#define KEY_FLAG_REVOKED 2 /* set if key had been revoked */
#define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */
#define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */
#define KEY_FLAG_NEGATIVE 5 /* set if key is negative */
/* 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;
unsigned long x[2];
void *p[2];
} 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
*/
typedef int (*request_key_actor_t)(struct key *key, struct key *authkey,
const char *op, void *aux);
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);
/* 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 some of the data from a key on revokation (optional)
* - the key's semaphore will be write-locked by the caller
*/
void (*revoke)(struct key *key);
/* 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);
/* handle request_key() for this type instead of invoking
* /sbin/request-key (optional)
* - key is the key to instantiate
* - authkey is the authority to assume when instantiating this key
* - op is the operation to be done, usually "create"
* - the call must not return until the instantiation process has run
* its course
*/
request_key_actor_t request_key;
/* 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,
struct task_struct *ctx,
key_perm_t perm,
unsigned long flags);
#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 */
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,
struct key *instkey);
extern int key_negate_and_link(struct key *key,
unsigned timeout,
struct key *keyring,
struct key *instkey);
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;
}
static inline void key_ref_put(key_ref_t key_ref)
{
key_put(key_ref_to_ptr(key_ref));
}
extern struct key *request_key(struct key_type *type,
const char *description,
const char *callout_info);
extern struct key *request_key_with_auxdata(struct key_type *type,
const char *description,
const char *callout_info,
void *aux);
extern int key_validate(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,
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_unlink(struct key *keyring,
struct key *key);
extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
struct task_struct *ctx,
unsigned long flags,
struct key *dest);
extern int keyring_clear(struct key *keyring);
extern key_ref_t keyring_search(key_ref_t keyring,
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);
extern void keyring_replace_payload(struct key *key, void *replacement);
#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,
struct task_struct *ctx);
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);
#define __install_session_keyring(tsk, keyring) \
({ \
struct key *old_session = tsk->signal->session_keyring; \
tsk->signal->session_keyring = keyring; \
old_session; \
})
#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 key_ref_put(k) do { } while(0)
#define make_key_ref(k) ({ NULL; })
#define key_ref_to_ptr(k) ({ NULL; })
#define is_key_possessed(k) 0
#define alloc_uid_keyring(u,c) 0
#define switch_uid_keyring(u) do { } while(0)
#define __install_session_keyring(t, k) ({ NULL; })
#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)
/* Initial keyrings */
extern struct key root_user_keyring;
extern struct key root_session_keyring;
#endif /* CONFIG_KEYS */
#endif /* __KERNEL__ */
#endif /* _LINUX_KEY_H */
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