/* 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> #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 #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; /*****************************************************************************/ /* * 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 */ union { time_t expiry; /* time at which key expires (or 0) */ time_t revoked_at; /* time at which key was revoked */ }; 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]; int reject_error; } type_data; /* key data * - this is used to hold the data actually used in cryptography or * whatever */ union { unsigned long value; void __rcu *rcudata; void *data; struct keyring_list __rcu *subscriptions; } payload; }; extern struct key *key_alloc(struct key_type *type, const char *desc, uid_t uid, gid_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 */ 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 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(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, uid_t uid, gid_t gid, const struct cred *cred, 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(struct key *key) { return key ? key->serial : 0; } /** * 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))) #ifdef CONFIG_SYSCTL extern ctl_table key_sysctls[]; #endif extern void key_replace_session_keyring(void); /* * 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_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) #define key_replace_session_keyring() do { } while(0) #endif /* CONFIG_KEYS */ #endif /* __KERNEL__ */ #endif /* _LINUX_KEY_H */