1 /* Definitions for key type implementations 2 * 3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells (dhowells@redhat.com) 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 union key_payload payload; /* Proposed payload */ 44 const void *data; /* Raw data */ 45 size_t datalen; /* Raw datalen */ 46 size_t quotalen; /* Quota length for proposed payload */ 47 time64_t expiry; /* Expiry time of key */ 48 } __randomize_layout; 49 50 typedef int (*request_key_actor_t)(struct key_construction *key, 51 const char *op, void *aux); 52 53 /* 54 * Preparsed matching criterion. 55 */ 56 struct key_match_data { 57 /* Comparison function, defaults to exact description match, but can be 58 * overridden by type->match_preparse(). Should return true if a match 59 * is found and false if not. 60 */ 61 bool (*cmp)(const struct key *key, 62 const struct key_match_data *match_data); 63 64 const void *raw_data; /* Raw match data */ 65 void *preparsed; /* For ->match_preparse() to stash stuff */ 66 unsigned lookup_type; /* Type of lookup for this search. */ 67 #define KEYRING_SEARCH_LOOKUP_DIRECT 0x0000 /* Direct lookup by description. */ 68 #define KEYRING_SEARCH_LOOKUP_ITERATE 0x0001 /* Iterative search. */ 69 }; 70 71 /* 72 * kernel managed key type definition 73 */ 74 struct key_type { 75 /* name of the type */ 76 const char *name; 77 78 /* default payload length for quota precalculation (optional) 79 * - this can be used instead of calling key_payload_reserve(), that 80 * function only needs to be called if the real datalen is different 81 */ 82 size_t def_datalen; 83 84 /* vet a description */ 85 int (*vet_description)(const char *description); 86 87 /* Preparse the data blob from userspace that is to be the payload, 88 * generating a proposed description and payload that will be handed to 89 * the instantiate() and update() ops. 90 */ 91 int (*preparse)(struct key_preparsed_payload *prep); 92 93 /* Free a preparse data structure. 94 */ 95 void (*free_preparse)(struct key_preparsed_payload *prep); 96 97 /* instantiate a key of this type 98 * - this method should call key_payload_reserve() to determine if the 99 * user's quota will hold the payload 100 */ 101 int (*instantiate)(struct key *key, struct key_preparsed_payload *prep); 102 103 /* update a key of this type (optional) 104 * - this method should call key_payload_reserve() to recalculate the 105 * quota consumption 106 * - the key must be locked against read when modifying 107 */ 108 int (*update)(struct key *key, struct key_preparsed_payload *prep); 109 110 /* Preparse the data supplied to ->match() (optional). The 111 * data to be preparsed can be found in match_data->raw_data. 112 * The lookup type can also be set by this function. 113 */ 114 int (*match_preparse)(struct key_match_data *match_data); 115 116 /* Free preparsed match data (optional). This should be supplied it 117 * ->match_preparse() is supplied. */ 118 void (*match_free)(struct key_match_data *match_data); 119 120 /* clear some of the data from a key on revokation (optional) 121 * - the key's semaphore will be write-locked by the caller 122 */ 123 void (*revoke)(struct key *key); 124 125 /* clear the data from a key (optional) */ 126 void (*destroy)(struct key *key); 127 128 /* describe a key */ 129 void (*describe)(const struct key *key, struct seq_file *p); 130 131 /* read a key's data (optional) 132 * - permission checks will be done by the caller 133 * - the key's semaphore will be readlocked by the caller 134 * - should return the amount of data that could be read, no matter how 135 * much is copied into the buffer 136 * - shouldn't do the copy if the buffer is NULL 137 */ 138 long (*read)(const struct key *key, char __user *buffer, size_t buflen); 139 140 /* handle request_key() for this type instead of invoking 141 * /sbin/request-key (optional) 142 * - key is the key to instantiate 143 * - authkey is the authority to assume when instantiating this key 144 * - op is the operation to be done, usually "create" 145 * - the call must not return until the instantiation process has run 146 * its course 147 */ 148 request_key_actor_t request_key; 149 150 /* Look up a keyring access restriction (optional) 151 * 152 * - NULL is a valid return value (meaning the requested restriction 153 * is known but will never block addition of a key) 154 * - should return -EINVAL if the restriction is unknown 155 */ 156 struct key_restriction *(*lookup_restriction)(const char *params); 157 158 /* internal fields */ 159 struct list_head link; /* link in types list */ 160 struct lock_class_key lock_class; /* key->sem lock class */ 161 } __randomize_layout; 162 163 extern struct key_type key_type_keyring; 164 165 extern int register_key_type(struct key_type *ktype); 166 extern void unregister_key_type(struct key_type *ktype); 167 168 extern int key_payload_reserve(struct key *key, size_t datalen); 169 extern int key_instantiate_and_link(struct key *key, 170 const void *data, 171 size_t datalen, 172 struct key *keyring, 173 struct key *instkey); 174 extern int key_reject_and_link(struct key *key, 175 unsigned timeout, 176 unsigned error, 177 struct key *keyring, 178 struct key *instkey); 179 extern void complete_request_key(struct key_construction *cons, int error); 180 181 static inline int key_negate_and_link(struct key *key, 182 unsigned timeout, 183 struct key *keyring, 184 struct key *instkey) 185 { 186 return key_reject_and_link(key, timeout, ENOKEY, keyring, instkey); 187 } 188 189 extern int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep); 190 191 #endif /* CONFIG_KEYS */ 192 #endif /* _LINUX_KEY_TYPE_H */ 193