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 /* 30 * Pre-parsed payload, used by key add, update and instantiate. 31 * 32 * This struct will be cleared and data and datalen will be set with the data 33 * and length parameters from the caller and quotalen will be set from 34 * def_datalen from the key type. Then if the preparse() op is provided by the 35 * key type, that will be called. Then the struct will be passed to the 36 * instantiate() or the update() op. 37 * 38 * If the preparse() op is given, the free_preparse() op will be called to 39 * clear the contents. 40 */ 41 struct key_preparsed_payload { 42 char *description; /* Proposed key description (or NULL) */ 43 void *type_data[2]; /* Private key-type data */ 44 void *payload; /* Proposed payload */ 45 const void *data; /* Raw data */ 46 size_t datalen; /* Raw datalen */ 47 size_t quotalen; /* Quota length for proposed payload */ 48 bool trusted; /* True if key is trusted */ 49 }; 50 51 typedef int (*request_key_actor_t)(struct key_construction *key, 52 const char *op, void *aux); 53 54 /* 55 * kernel managed key type definition 56 */ 57 struct key_type { 58 /* name of the type */ 59 const char *name; 60 61 /* default payload length for quota precalculation (optional) 62 * - this can be used instead of calling key_payload_reserve(), that 63 * function only needs to be called if the real datalen is different 64 */ 65 size_t def_datalen; 66 67 /* Default key search algorithm. */ 68 unsigned def_lookup_type; 69 #define KEYRING_SEARCH_LOOKUP_DIRECT 0x0000 /* Direct lookup by description. */ 70 #define KEYRING_SEARCH_LOOKUP_ITERATE 0x0001 /* Iterative search. */ 71 72 /* vet a description */ 73 int (*vet_description)(const char *description); 74 75 /* Preparse the data blob from userspace that is to be the payload, 76 * generating a proposed description and payload that will be handed to 77 * the instantiate() and update() ops. 78 */ 79 int (*preparse)(struct key_preparsed_payload *prep); 80 81 /* Free a preparse data structure. 82 */ 83 void (*free_preparse)(struct key_preparsed_payload *prep); 84 85 /* instantiate a key of this type 86 * - this method should call key_payload_reserve() to determine if the 87 * user's quota will hold the payload 88 */ 89 int (*instantiate)(struct key *key, struct key_preparsed_payload *prep); 90 91 /* update a key of this type (optional) 92 * - this method should call key_payload_reserve() to recalculate the 93 * quota consumption 94 * - the key must be locked against read when modifying 95 */ 96 int (*update)(struct key *key, struct key_preparsed_payload *prep); 97 98 /* match a key against a description */ 99 int (*match)(const struct key *key, const void *desc); 100 101 /* clear some of the data from a key on revokation (optional) 102 * - the key's semaphore will be write-locked by the caller 103 */ 104 void (*revoke)(struct key *key); 105 106 /* clear the data from a key (optional) */ 107 void (*destroy)(struct key *key); 108 109 /* describe a key */ 110 void (*describe)(const struct key *key, struct seq_file *p); 111 112 /* read a key's data (optional) 113 * - permission checks will be done by the caller 114 * - the key's semaphore will be readlocked by the caller 115 * - should return the amount of data that could be read, no matter how 116 * much is copied into the buffer 117 * - shouldn't do the copy if the buffer is NULL 118 */ 119 long (*read)(const struct key *key, char __user *buffer, size_t buflen); 120 121 /* handle request_key() for this type instead of invoking 122 * /sbin/request-key (optional) 123 * - key is the key to instantiate 124 * - authkey is the authority to assume when instantiating this key 125 * - op is the operation to be done, usually "create" 126 * - the call must not return until the instantiation process has run 127 * its course 128 */ 129 request_key_actor_t request_key; 130 131 /* internal fields */ 132 struct list_head link; /* link in types list */ 133 struct lock_class_key lock_class; /* key->sem lock class */ 134 }; 135 136 extern struct key_type key_type_keyring; 137 138 extern int register_key_type(struct key_type *ktype); 139 extern void unregister_key_type(struct key_type *ktype); 140 141 extern int key_payload_reserve(struct key *key, size_t datalen); 142 extern int key_instantiate_and_link(struct key *key, 143 const void *data, 144 size_t datalen, 145 struct key *keyring, 146 struct key *instkey); 147 extern int key_reject_and_link(struct key *key, 148 unsigned timeout, 149 unsigned error, 150 struct key *keyring, 151 struct key *instkey); 152 extern void complete_request_key(struct key_construction *cons, int error); 153 154 static inline int key_negate_and_link(struct key *key, 155 unsigned timeout, 156 struct key *keyring, 157 struct key *instkey) 158 { 159 return key_reject_and_link(key, timeout, ENOKEY, keyring, instkey); 160 } 161 162 #endif /* CONFIG_KEYS */ 163 #endif /* _LINUX_KEY_TYPE_H */ 164