1 /* Definitions for key type implementations 2 * 3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells ([email protected]) 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public Licence 8 * as published by the Free Software Foundation; either version 9 * 2 of the Licence, or (at your option) any later version. 10 */ 11 12 #ifndef _LINUX_KEY_TYPE_H 13 #define _LINUX_KEY_TYPE_H 14 15 #include <linux/key.h> 16 #include <linux/errno.h> 17 18 #ifdef CONFIG_KEYS 19 20 /* 21 * key under-construction record 22 * - passed to the request_key actor if supplied 23 */ 24 struct key_construction { 25 struct key *key; /* key being constructed */ 26 struct key *authkey;/* authorisation for key being constructed */ 27 }; 28 29 typedef int (*request_key_actor_t)(struct key_construction *key, 30 const char *op, void *aux); 31 32 /* 33 * kernel managed key type definition 34 */ 35 struct key_type { 36 /* name of the type */ 37 const char *name; 38 39 /* default payload length for quota precalculation (optional) 40 * - this can be used instead of calling key_payload_reserve(), that 41 * function only needs to be called if the real datalen is different 42 */ 43 size_t def_datalen; 44 45 /* vet a description */ 46 int (*vet_description)(const char *description); 47 48 /* instantiate a key of this type 49 * - this method should call key_payload_reserve() to determine if the 50 * user's quota will hold the payload 51 */ 52 int (*instantiate)(struct key *key, const void *data, size_t datalen); 53 54 /* update a key of this type (optional) 55 * - this method should call key_payload_reserve() to recalculate the 56 * quota consumption 57 * - the key must be locked against read when modifying 58 */ 59 int (*update)(struct key *key, const void *data, size_t datalen); 60 61 /* match a key against a description */ 62 int (*match)(const struct key *key, const void *desc); 63 64 /* clear some of the data from a key on revokation (optional) 65 * - the key's semaphore will be write-locked by the caller 66 */ 67 void (*revoke)(struct key *key); 68 69 /* clear the data from a key (optional) */ 70 void (*destroy)(struct key *key); 71 72 /* describe a key */ 73 void (*describe)(const struct key *key, struct seq_file *p); 74 75 /* read a key's data (optional) 76 * - permission checks will be done by the caller 77 * - the key's semaphore will be readlocked by the caller 78 * - should return the amount of data that could be read, no matter how 79 * much is copied into the buffer 80 * - shouldn't do the copy if the buffer is NULL 81 */ 82 long (*read)(const struct key *key, char __user *buffer, size_t buflen); 83 84 /* handle request_key() for this type instead of invoking 85 * /sbin/request-key (optional) 86 * - key is the key to instantiate 87 * - authkey is the authority to assume when instantiating this key 88 * - op is the operation to be done, usually "create" 89 * - the call must not return until the instantiation process has run 90 * its course 91 */ 92 request_key_actor_t request_key; 93 94 /* internal fields */ 95 struct list_head link; /* link in types list */ 96 struct lock_class_key lock_class; /* key->sem lock class */ 97 }; 98 99 extern struct key_type key_type_keyring; 100 101 extern int register_key_type(struct key_type *ktype); 102 extern void unregister_key_type(struct key_type *ktype); 103 104 extern int key_payload_reserve(struct key *key, size_t datalen); 105 extern int key_instantiate_and_link(struct key *key, 106 const void *data, 107 size_t datalen, 108 struct key *keyring, 109 struct key *instkey); 110 extern int key_reject_and_link(struct key *key, 111 unsigned timeout, 112 unsigned error, 113 struct key *keyring, 114 struct key *instkey); 115 extern void complete_request_key(struct key_construction *cons, int error); 116 117 static inline int key_negate_and_link(struct key *key, 118 unsigned timeout, 119 struct key *keyring, 120 struct key *instkey) 121 { 122 return key_reject_and_link(key, timeout, ENOKEY, keyring, instkey); 123 } 124 125 #endif /* CONFIG_KEYS */ 126 #endif /* _LINUX_KEY_TYPE_H */ 127