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.rst
14 #include <linux/sched.h>
15 #include <linux/err.h>
16 #include <linux/seq_file.h>
17 #include <linux/slab.h>
18 #include <linux/uaccess.h>
20 #include <keys/request_key_auth-type.h>
22 static int request_key_auth_preparse(struct key_preparsed_payload *);
23 static void request_key_auth_free_preparse(struct key_preparsed_payload *);
24 static int request_key_auth_instantiate(struct key *,
25 struct key_preparsed_payload *);
26 static void request_key_auth_describe(const struct key *, struct seq_file *);
27 static void request_key_auth_revoke(struct key *);
28 static void request_key_auth_destroy(struct key *);
29 static long request_key_auth_read(const struct key *, char __user *, size_t);
32 * The request-key authorisation key type definition.
34 struct key_type key_type_request_key_auth = {
35 .name = ".request_key_auth",
36 .def_datalen = sizeof(struct request_key_auth),
37 .preparse = request_key_auth_preparse,
38 .free_preparse = request_key_auth_free_preparse,
39 .instantiate = request_key_auth_instantiate,
40 .describe = request_key_auth_describe,
41 .revoke = request_key_auth_revoke,
42 .destroy = request_key_auth_destroy,
43 .read = request_key_auth_read,
46 static int request_key_auth_preparse(struct key_preparsed_payload *prep)
51 static void request_key_auth_free_preparse(struct key_preparsed_payload *prep)
56 * Instantiate a request-key authorisation key.
58 static int request_key_auth_instantiate(struct key *key,
59 struct key_preparsed_payload *prep)
61 key->payload.data[0] = (struct request_key_auth *)prep->data;
66 * Describe an authorisation token.
68 static void request_key_auth_describe(const struct key *key,
71 struct request_key_auth *rka = get_request_key_auth(key);
74 seq_puts(m, key->description);
75 if (key_is_positive(key))
76 seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len);
80 * Read the callout_info data (retrieves the callout information).
81 * - the key's semaphore is read-locked
83 static long request_key_auth_read(const struct key *key,
84 char __user *buffer, size_t buflen)
86 struct request_key_auth *rka = get_request_key_auth(key);
90 datalen = rka->callout_len;
93 /* we can return the data as is */
94 if (buffer && buflen > 0) {
98 if (copy_to_user(buffer, rka->callout_info, buflen) != 0)
106 * Handle revocation of an authorisation token key.
108 * Called with the key sem write-locked.
110 static void request_key_auth_revoke(struct key *key)
112 struct request_key_auth *rka = get_request_key_auth(key);
114 kenter("{%d}", key->serial);
122 static void free_request_key_auth(struct request_key_auth *rka)
126 key_put(rka->target_key);
127 key_put(rka->dest_keyring);
130 kfree(rka->callout_info);
135 * Destroy an instantiation authorisation token key.
137 static void request_key_auth_destroy(struct key *key)
139 struct request_key_auth *rka = get_request_key_auth(key);
141 kenter("{%d}", key->serial);
143 free_request_key_auth(rka);
147 * Create an authorisation token for /sbin/request-key or whoever to gain
148 * access to the caller's security data.
150 struct key *request_key_auth_new(struct key *target, const char *op,
151 const void *callout_info, size_t callout_len,
152 struct key *dest_keyring)
154 struct request_key_auth *rka, *irka;
155 const struct cred *cred = current->cred;
156 struct key *authkey = NULL;
160 kenter("%d,", target->serial);
162 /* allocate a auth record */
163 rka = kzalloc(sizeof(*rka), GFP_KERNEL);
166 rka->callout_info = kmemdup(callout_info, callout_len, GFP_KERNEL);
167 if (!rka->callout_info)
169 rka->callout_len = callout_len;
170 strlcpy(rka->op, op, sizeof(rka->op));
172 /* see if the calling process is already servicing the key request of
174 if (cred->request_key_auth) {
175 /* it is - use that instantiation context here too */
176 down_read(&cred->request_key_auth->sem);
178 /* if the auth key has been revoked, then the key we're
179 * servicing is already instantiated */
180 if (test_bit(KEY_FLAG_REVOKED,
181 &cred->request_key_auth->flags)) {
182 up_read(&cred->request_key_auth->sem);
187 irka = cred->request_key_auth->payload.data[0];
188 rka->cred = get_cred(irka->cred);
189 rka->pid = irka->pid;
191 up_read(&cred->request_key_auth->sem);
194 /* it isn't - use this process as the context */
195 rka->cred = get_cred(cred);
196 rka->pid = current->pid;
199 rka->target_key = key_get(target);
200 rka->dest_keyring = key_get(dest_keyring);
202 /* allocate the auth key */
203 sprintf(desc, "%x", target->serial);
205 authkey = key_alloc(&key_type_request_key_auth, desc,
206 cred->fsuid, cred->fsgid, cred,
207 KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH |
208 KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA, NULL);
209 if (IS_ERR(authkey)) {
210 ret = PTR_ERR(authkey);
214 /* construct the auth key */
215 ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL);
217 goto error_put_authkey;
219 kleave(" = {%d,%d}", authkey->serial, refcount_read(&authkey->usage));
225 free_request_key_auth(rka);
232 * Search the current process's keyrings for the authorisation key for
233 * instantiation of a key.
235 struct key *key_get_instantiation_authkey(key_serial_t target_id)
237 char description[16];
238 struct keyring_search_context ctx = {
239 .index_key.type = &key_type_request_key_auth,
240 .index_key.description = description,
241 .cred = current_cred(),
242 .match_data.cmp = key_default_cmp,
243 .match_data.raw_data = description,
244 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
245 .flags = KEYRING_SEARCH_DO_STATE_CHECK,
248 key_ref_t authkey_ref;
250 ctx.index_key.desc_len = sprintf(description, "%x", target_id);
252 authkey_ref = search_process_keyrings(&ctx);
254 if (IS_ERR(authkey_ref)) {
255 authkey = ERR_CAST(authkey_ref);
256 if (authkey == ERR_PTR(-EAGAIN))
257 authkey = ERR_PTR(-ENOKEY);
261 authkey = key_ref_to_ptr(authkey_ref);
262 if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) {
264 authkey = ERR_PTR(-EKEYREVOKED);