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Diffstat (limited to 'include/linux/key.h')
| -rw-r--r-- | include/linux/key.h | 376 |
1 files changed, 376 insertions, 0 deletions
diff --git a/include/linux/key.h b/include/linux/key.h new file mode 100644 index 000000000..e1d4715f3 --- /dev/null +++ b/include/linux/key.h @@ -0,0 +1,376 @@ +/* Authentication token and access key management + * + * Copyright (C) 2004, 2007 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/security/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 <linux/sysctl.h> +#include <linux/rwsem.h> +#include <linux/atomic.h> +#include <linux/assoc_array.h> + +#ifdef __KERNEL__ +#include <linux/uidgid.h> + +/* 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 + +#define KEY_PERM_UNDEF 0xffffffff + +struct seq_file; +struct user_struct; +struct signal_struct; +struct cred; + +struct key_type; +struct key_owner; +struct keyring_list; +struct keyring_name; + +struct keyring_index_key { + struct key_type *type; + const char *description; + size_t desc_len; +}; + +/*****************************************************************************/ +/* + * 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, + bool 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 bool 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 */ + union { + struct list_head graveyard_link; + struct rb_node serial_node; + }; + struct rw_semaphore sem; /* change vs change sem */ + struct key_user *user; /* owner of this key */ + void *security; /* security data for this key */ + union { + time_t expiry; /* time at which key expires (or 0) */ + time_t revoked_at; /* time at which key was revoked */ + }; + time_t last_used_at; /* last time used for LRU keyring discard */ + kuid_t uid; + kgid_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 */ +#define KEY_FLAG_ROOT_CAN_CLEAR 6 /* set if key can be cleared by root without permission */ +#define KEY_FLAG_INVALIDATED 7 /* set if key has been invalidated */ +#define KEY_FLAG_TRUSTED 8 /* set if key is trusted */ +#define KEY_FLAG_TRUSTED_ONLY 9 /* set if keyring only accepts links to trusted keys */ +#define KEY_FLAG_BUILTIN 10 /* set if key is builtin */ +#define KEY_FLAG_ROOT_CAN_INVAL 11 /* set if key can be invalidated by root without permission */ + + /* the key type and key description string + * - the desc is used to match a key against search criteria + * - it should be a printable string + * - eg: for krb5 AFS, this might be "afs@REDHAT.COM" + */ + union { + struct keyring_index_key index_key; + struct { + struct key_type *type; /* type of key */ + 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]; + int reject_error; + } type_data; + + /* key data + * - this is used to hold the data actually used in cryptography or + * whatever + */ + union { + union { + unsigned long value; + void __rcu *rcudata; + void *data; + void *data2[2]; + } payload; + struct assoc_array keys; + }; +}; + +extern struct key *key_alloc(struct key_type *type, + const char *desc, + kuid_t uid, kgid_t gid, + const struct cred *cred, + 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 */ +#define KEY_ALLOC_TRUSTED 0x0004 /* Key should be flagged as trusted */ + +extern void key_revoke(struct key *key); +extern void key_invalidate(struct key *key); +extern void key_put(struct key *key); + +static inline struct key *__key_get(struct key *key) +{ + atomic_inc(&key->usage); + return key; +} + +static inline struct key *key_get(struct key *key) +{ + return key ? __key_get(key) : 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 void *callout_info, + size_t callout_len, + void *aux); + +extern struct key *request_key_async(struct key_type *type, + const char *description, + const void *callout_info, + size_t callout_len); + +extern struct key *request_key_async_with_auxdata(struct key_type *type, + const char *description, + const void *callout_info, + size_t callout_len, + void *aux); + +extern int wait_for_key_construction(struct key *key, bool intr); + +extern int key_validate(const 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, + key_perm_t perm, + 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, kuid_t uid, kgid_t gid, + const struct cred *cred, + key_perm_t perm, + 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); + +static inline key_serial_t key_serial(const struct key *key) +{ + return key ? key->serial : 0; +} + +extern void key_set_timeout(struct key *, unsigned); + +/* + * The permissions required on a key that we're looking up. + */ +#define KEY_NEED_VIEW 0x01 /* Require permission to view attributes */ +#define KEY_NEED_READ 0x02 /* Require permission to read content */ +#define KEY_NEED_WRITE 0x04 /* Require permission to update / modify */ +#define KEY_NEED_SEARCH 0x08 /* Require permission to search (keyring) or find (key) */ +#define KEY_NEED_LINK 0x10 /* Require permission to link */ +#define KEY_NEED_SETATTR 0x20 /* Require permission to change attributes */ +#define KEY_NEED_ALL 0x3f /* All the above permissions */ + +/** + * key_is_instantiated - Determine if a key has been positively instantiated + * @key: The key to check. + * + * Return true if the specified key has been positively instantiated, false + * otherwise. + */ +static inline bool key_is_instantiated(const struct key *key) +{ + return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) && + !test_bit(KEY_FLAG_NEGATIVE, &key->flags); +} + +#define rcu_dereference_key(KEY) \ + (rcu_dereference_protected((KEY)->payload.rcudata, \ + rwsem_is_locked(&((struct key *)(KEY))->sem))) + +#define rcu_assign_keypointer(KEY, PAYLOAD) \ +do { \ + rcu_assign_pointer((KEY)->payload.rcudata, (PAYLOAD)); \ +} while (0) + +#ifdef CONFIG_SYSCTL +extern struct ctl_table key_sysctls[]; +#endif +/* + * the userspace interface + */ +extern int install_thread_keyring_to_cred(struct cred *cred); +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_revoke(k) do { } while(0) +#define key_invalidate(k) do { } while(0) +#define key_put(k) do { } while(0) +#define key_ref_put(k) do { } while(0) +#define make_key_ref(k, p) NULL +#define key_ref_to_ptr(k) NULL +#define is_key_possessed(k) 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 */ |