1 /* Request key authorisation token key definition.
3 * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
11 * See Documentation/security/keys-request-key.txt
14 #include <linux/module.h>
15 #include <linux/sched.h>
16 #include <linux/err.h>
17 #include <linux/seq_file.h>
18 #include <linux/slab.h>
19 #include <asm/uaccess.h>
22 static int request_key_auth_instantiate(struct key *, const void *, size_t);
23 static void request_key_auth_describe(const struct key *, struct seq_file *);
24 static void request_key_auth_revoke(struct key *);
25 static void request_key_auth_destroy(struct key *);
26 static long request_key_auth_read(const struct key *, char __user *, size_t);
29 * The request-key authorisation key type definition.
31 struct key_type key_type_request_key_auth = {
32 .name = ".request_key_auth",
33 .def_datalen = sizeof(struct request_key_auth),
34 .instantiate = request_key_auth_instantiate,
35 .describe = request_key_auth_describe,
36 .revoke = request_key_auth_revoke,
37 .destroy = request_key_auth_destroy,
38 .read = request_key_auth_read,
42 * Instantiate a request-key authorisation key.
44 static int request_key_auth_instantiate(struct key *key,
48 key->payload.data = (struct request_key_auth *) data;
53 * Describe an authorisation token.
55 static void request_key_auth_describe(const struct key *key,
58 struct request_key_auth *rka = key->payload.data;
61 seq_puts(m, key->description);
62 if (key_is_instantiated(key))
63 seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len);
67 * Read the callout_info data (retrieves the callout information).
68 * - the key's semaphore is read-locked
70 static long request_key_auth_read(const struct key *key,
71 char __user *buffer, size_t buflen)
73 struct request_key_auth *rka = key->payload.data;
77 datalen = rka->callout_len;
80 /* we can return the data as is */
81 if (buffer && buflen > 0) {
85 if (copy_to_user(buffer, rka->callout_info, buflen) != 0)
93 * Handle revocation of an authorisation token key.
95 * Called with the key sem write-locked.
97 static void request_key_auth_revoke(struct key *key)
99 struct request_key_auth *rka = key->payload.data;
101 kenter("{%d}", key->serial);
109 static void free_request_key_auth(struct request_key_auth *rka)
113 key_put(rka->target_key);
114 key_put(rka->dest_keyring);
117 kfree(rka->callout_info);
122 * Destroy an instantiation authorisation token key.
124 static void request_key_auth_destroy(struct key *key)
126 struct request_key_auth *rka = key->payload.data;
128 kenter("{%d}", key->serial);
130 free_request_key_auth(rka);
134 * Create an authorisation token for /sbin/request-key or whoever to gain
135 * access to the caller's security data.
137 struct key *request_key_auth_new(struct key *target, const void *callout_info,
138 size_t callout_len, struct key *dest_keyring)
140 struct request_key_auth *rka, *irka;
141 const struct cred *cred = current->cred;
142 struct key *authkey = NULL;
146 kenter("%d,", target->serial);
148 /* allocate a auth record */
149 rka = kzalloc(sizeof(*rka), GFP_KERNEL);
152 rka->callout_info = kmalloc(callout_len, GFP_KERNEL);
153 if (!rka->callout_info)
156 /* see if the calling process is already servicing the key request of
158 if (cred->request_key_auth) {
159 /* it is - use that instantiation context here too */
160 down_read(&cred->request_key_auth->sem);
162 /* if the auth key has been revoked, then the key we're
163 * servicing is already instantiated */
164 if (test_bit(KEY_FLAG_REVOKED,
165 &cred->request_key_auth->flags)) {
166 up_read(&cred->request_key_auth->sem);
171 irka = cred->request_key_auth->payload.data;
172 rka->cred = get_cred(irka->cred);
173 rka->pid = irka->pid;
175 up_read(&cred->request_key_auth->sem);
178 /* it isn't - use this process as the context */
179 rka->cred = get_cred(cred);
180 rka->pid = current->pid;
183 rka->target_key = key_get(target);
184 rka->dest_keyring = key_get(dest_keyring);
185 memcpy(rka->callout_info, callout_info, callout_len);
186 rka->callout_len = callout_len;
188 /* allocate the auth key */
189 sprintf(desc, "%x", target->serial);
191 authkey = key_alloc(&key_type_request_key_auth, desc,
192 cred->fsuid, cred->fsgid, cred,
193 KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH |
194 KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA);
195 if (IS_ERR(authkey)) {
196 ret = PTR_ERR(authkey);
200 /* construct the auth key */
201 ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL);
203 goto error_put_authkey;
205 kleave(" = {%d,%d}", authkey->serial, atomic_read(&authkey->usage));
211 free_request_key_auth(rka);
218 * See if an authorisation key is associated with a particular key.
220 static int key_get_instantiation_authkey_match(const struct key *key,
223 struct request_key_auth *rka = key->payload.data;
224 key_serial_t id = (key_serial_t)(unsigned long) _id;
226 return rka->target_key->serial == id;
230 * Search the current process's keyrings for the authorisation key for
231 * instantiation of a key.
233 struct key *key_get_instantiation_authkey(key_serial_t target_id)
235 const struct cred *cred = current_cred();
237 key_ref_t authkey_ref;
239 authkey_ref = search_process_keyrings(
240 &key_type_request_key_auth,
241 (void *) (unsigned long) target_id,
242 key_get_instantiation_authkey_match,
245 if (IS_ERR(authkey_ref)) {
246 authkey = ERR_CAST(authkey_ref);
247 if (authkey == ERR_PTR(-EAGAIN))
248 authkey = ERR_PTR(-ENOKEY);
252 authkey = key_ref_to_ptr(authkey_ref);
253 if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) {
255 authkey = ERR_PTR(-EKEYREVOKED);