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Diffstat (limited to 'include/linux/key.h')
| -rw-r--r-- | include/linux/key.h | 291 |
1 files changed, 291 insertions, 0 deletions
diff --git a/include/linux/key.h b/include/linux/key.h new file mode 100644 index 00000000000..6aa46d0e812 --- /dev/null +++ b/include/linux/key.h @@ -0,0 +1,291 @@ +/* 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 */ |