/* 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 */