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 */ 24struct 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 */ 41struct key_preparsed_payload { 42 char *description; /* Proposed key description (or NULL) */ 43 void *type_data[2]; /* Private key-type data */ 44 void *payload[2]; /* Proposed payload */ 45 const void *data; /* Raw data */ 46 size_t datalen; /* Raw datalen */ 47 size_t quotalen; /* Quota length for proposed payload */ 48 time_t expiry; /* Expiry time of key */ 49 bool trusted; /* True if key is trusted */ 50}; 51 52typedef int (*request_key_actor_t)(struct key_construction *key, 53 const char *op, void *aux); 54 55/* 56 * Preparsed matching criterion. 57 */ 58struct key_match_data { 59 /* Comparison function, defaults to exact description match, but can be 60 * overridden by type->match_preparse(). Should return true if a match 61 * is found and false if not. 62 */ 63 bool (*cmp)(const struct key *key, 64 const struct key_match_data *match_data); 65 66 const void *raw_data; /* Raw match data */ 67 void *preparsed; /* For ->match_preparse() to stash stuff */ 68 unsigned lookup_type; /* Type of lookup for this search. */ 69#define KEYRING_SEARCH_LOOKUP_DIRECT 0x0000 /* Direct lookup by description. */ 70#define KEYRING_SEARCH_LOOKUP_ITERATE 0x0001 /* Iterative search. */ 71}; 72 73/* 74 * kernel managed key type definition 75 */ 76struct key_type { 77 /* name of the type */ 78 const char *name; 79 80 /* default payload length for quota precalculation (optional) 81 * - this can be used instead of calling key_payload_reserve(), that 82 * function only needs to be called if the real datalen is different 83 */ 84 size_t def_datalen; 85 86 /* vet a description */ 87 int (*vet_description)(const char *description); 88 89 /* Preparse the data blob from userspace that is to be the payload, 90 * generating a proposed description and payload that will be handed to 91 * the instantiate() and update() ops. 92 */ 93 int (*preparse)(struct key_preparsed_payload *prep); 94 95 /* Free a preparse data structure. 96 */ 97 void (*free_preparse)(struct key_preparsed_payload *prep); 98 99 /* instantiate a key of this type 100 * - this method should call key_payload_reserve() to determine if the 101 * user's quota will hold the payload 102 */ 103 int (*instantiate)(struct key *key, struct key_preparsed_payload *prep); 104 105 /* update a key of this type (optional) 106 * - this method should call key_payload_reserve() to recalculate the 107 * quota consumption 108 * - the key must be locked against read when modifying 109 */ 110 int (*update)(struct key *key, struct key_preparsed_payload *prep); 111 112 /* Preparse the data supplied to ->match() (optional). The 113 * data to be preparsed can be found in match_data->raw_data. 114 * The lookup type can also be set by this function. 115 */ 116 int (*match_preparse)(struct key_match_data *match_data); 117 118 /* Free preparsed match data (optional). This should be supplied it 119 * ->match_preparse() is supplied. */ 120 void (*match_free)(struct key_match_data *match_data); 121 122 /* clear some of the data from a key on revokation (optional) 123 * - the key's semaphore will be write-locked by the caller 124 */ 125 void (*revoke)(struct key *key); 126 127 /* clear the data from a key (optional) */ 128 void (*destroy)(struct key *key); 129 130 /* describe a key */ 131 void (*describe)(const struct key *key, struct seq_file *p); 132 133 /* read a key's data (optional) 134 * - permission checks will be done by the caller 135 * - the key's semaphore will be readlocked by the caller 136 * - should return the amount of data that could be read, no matter how 137 * much is copied into the buffer 138 * - shouldn't do the copy if the buffer is NULL 139 */ 140 long (*read)(const struct key *key, char __user *buffer, size_t buflen); 141 142 /* handle request_key() for this type instead of invoking 143 * /sbin/request-key (optional) 144 * - key is the key to instantiate 145 * - authkey is the authority to assume when instantiating this key 146 * - op is the operation to be done, usually "create" 147 * - the call must not return until the instantiation process has run 148 * its course 149 */ 150 request_key_actor_t request_key; 151 152 /* internal fields */ 153 struct list_head link; /* link in types list */ 154 struct lock_class_key lock_class; /* key->sem lock class */ 155}; 156 157extern struct key_type key_type_keyring; 158 159extern int register_key_type(struct key_type *ktype); 160extern void unregister_key_type(struct key_type *ktype); 161 162extern int key_payload_reserve(struct key *key, size_t datalen); 163extern int key_instantiate_and_link(struct key *key, 164 const void *data, 165 size_t datalen, 166 struct key *keyring, 167 struct key *instkey); 168extern int key_reject_and_link(struct key *key, 169 unsigned timeout, 170 unsigned error, 171 struct key *keyring, 172 struct key *instkey); 173extern void complete_request_key(struct key_construction *cons, int error); 174 175static inline int key_negate_and_link(struct key *key, 176 unsigned timeout, 177 struct key *keyring, 178 struct key *instkey) 179{ 180 return key_reject_and_link(key, timeout, ENOKEY, keyring, instkey); 181} 182 183extern int generic_key_instantiate(struct key *key, struct key_preparsed_payload *prep); 184 185#endif /* CONFIG_KEYS */ 186#endif /* _LINUX_KEY_TYPE_H */ 187