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/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 <linux/uaccess.h>
21 #include <keys/request_key_auth-type.h>
23 static int request_key_auth_preparse(struct key_preparsed_payload *);
24 static void request_key_auth_free_preparse(struct key_preparsed_payload *);
25 static int request_key_auth_instantiate(struct key *,
26 struct key_preparsed_payload *);
27 static void request_key_auth_describe(const struct key *, struct seq_file *);
28 static void request_key_auth_revoke(struct key *);
29 static void request_key_auth_destroy(struct key *);
30 static long request_key_auth_read(const struct key *, char *, size_t);
33 * The request-key authorisation key type definition.
35 struct key_type key_type_request_key_auth = {
36 .name = ".request_key_auth",
37 .def_datalen = sizeof(struct request_key_auth),
38 .preparse = request_key_auth_preparse,
39 .free_preparse = request_key_auth_free_preparse,
40 .instantiate = request_key_auth_instantiate,
41 .describe = request_key_auth_describe,
42 .revoke = request_key_auth_revoke,
43 .destroy = request_key_auth_destroy,
44 .read = request_key_auth_read,
47 static int request_key_auth_preparse(struct key_preparsed_payload *prep)
52 static void request_key_auth_free_preparse(struct key_preparsed_payload *prep)
57 * Instantiate a request-key authorisation key.
59 static int request_key_auth_instantiate(struct key *key,
60 struct key_preparsed_payload *prep)
62 key->payload.data[0] = (struct request_key_auth *)prep->data;
67 * Describe an authorisation token.
69 static void request_key_auth_describe(const struct key *key,
72 struct request_key_auth *rka = get_request_key_auth(key);
78 seq_puts(m, key->description);
79 if (key_is_positive(key))
80 seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len);
84 * Read the callout_info data (retrieves the callout information).
85 * - the key's semaphore is read-locked
87 static long request_key_auth_read(const struct key *key,
88 char *buffer, size_t buflen)
90 struct request_key_auth *rka = get_request_key_auth(key);
97 datalen = rka->callout_len;
100 /* we can return the data as is */
101 if (buffer && buflen > 0) {
102 if (buflen > datalen)
105 memcpy(buffer, rka->callout_info, buflen);
112 * Handle revocation of an authorisation token key.
114 * Called with the key sem write-locked.
116 static void request_key_auth_revoke(struct key *key)
118 struct request_key_auth *rka = get_request_key_auth(key);
120 kenter("{%d}", key->serial);
128 static void free_request_key_auth(struct request_key_auth *rka)
132 key_put(rka->target_key);
133 key_put(rka->dest_keyring);
136 kfree(rka->callout_info);
141 * Destroy an instantiation authorisation token key.
143 static void request_key_auth_destroy(struct key *key)
145 struct request_key_auth *rka = get_request_key_auth(key);
147 kenter("{%d}", key->serial);
149 free_request_key_auth(rka);
153 * Create an authorisation token for /sbin/request-key or whoever to gain
154 * access to the caller's security data.
156 struct key *request_key_auth_new(struct key *target, const char *op,
157 const void *callout_info, size_t callout_len,
158 struct key *dest_keyring)
160 struct request_key_auth *rka, *irka;
161 const struct cred *cred = current->cred;
162 struct key *authkey = NULL;
166 kenter("%d,", target->serial);
168 /* allocate a auth record */
169 rka = kzalloc(sizeof(*rka), GFP_KERNEL);
172 rka->callout_info = kmemdup(callout_info, callout_len, GFP_KERNEL);
173 if (!rka->callout_info)
175 rka->callout_len = callout_len;
176 strlcpy(rka->op, op, sizeof(rka->op));
178 /* see if the calling process is already servicing the key request of
180 if (cred->request_key_auth) {
181 /* it is - use that instantiation context here too */
182 down_read(&cred->request_key_auth->sem);
184 /* if the auth key has been revoked, then the key we're
185 * servicing is already instantiated */
186 if (test_bit(KEY_FLAG_REVOKED,
187 &cred->request_key_auth->flags)) {
188 up_read(&cred->request_key_auth->sem);
193 irka = cred->request_key_auth->payload.data[0];
194 rka->cred = get_cred(irka->cred);
195 rka->pid = irka->pid;
197 up_read(&cred->request_key_auth->sem);
200 /* it isn't - use this process as the context */
201 rka->cred = get_cred(cred);
202 rka->pid = current->pid;
205 rka->target_key = key_get(target);
206 rka->dest_keyring = key_get(dest_keyring);
208 /* allocate the auth key */
209 sprintf(desc, "%x", target->serial);
211 authkey = key_alloc(&key_type_request_key_auth, desc,
212 cred->fsuid, cred->fsgid, cred,
213 KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH |
214 KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA, NULL);
215 if (IS_ERR(authkey)) {
216 ret = PTR_ERR(authkey);
220 /* construct the auth key */
221 ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL);
223 goto error_put_authkey;
225 kleave(" = {%d,%d}", authkey->serial, refcount_read(&authkey->usage));
231 free_request_key_auth(rka);
238 * Search the current process's keyrings for the authorisation key for
239 * instantiation of a key.
241 struct key *key_get_instantiation_authkey(key_serial_t target_id)
243 char description[16];
244 struct keyring_search_context ctx = {
245 .index_key.type = &key_type_request_key_auth,
246 .index_key.description = description,
247 .cred = current_cred(),
248 .match_data.cmp = key_default_cmp,
249 .match_data.raw_data = description,
250 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
251 .flags = KEYRING_SEARCH_DO_STATE_CHECK,
254 key_ref_t authkey_ref;
256 ctx.index_key.desc_len = sprintf(description, "%x", target_id);
258 authkey_ref = search_process_keyrings(&ctx);
260 if (IS_ERR(authkey_ref)) {
261 authkey = ERR_CAST(authkey_ref);
262 if (authkey == ERR_PTR(-EAGAIN))
263 authkey = ERR_PTR(-ENOKEY);
267 authkey = key_ref_to_ptr(authkey_ref);
268 if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) {
270 authkey = ERR_PTR(-EKEYREVOKED);