blob: 510f7be73a2d4e954cc8de34bed9580e5cc4a47b [file] [log] [blame]
David Howells3e301482005-06-23 22:00:56 -07001/* request_key_auth.c: request key authorisation controlling key def
2 *
3 * Copyright (C) 2005 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 License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
David Howellsf1a9bad2005-10-07 15:04:52 +010010 *
11 * See Documentation/keys-request-key.txt
David Howells3e301482005-06-23 22:00:56 -070012 */
13
14#include <linux/module.h>
15#include <linux/sched.h>
16#include <linux/err.h>
17#include <linux/seq_file.h>
David Howellsb5f545c2006-01-08 01:02:47 -080018#include <asm/uaccess.h>
David Howells3e301482005-06-23 22:00:56 -070019#include "internal.h"
20
21static int request_key_auth_instantiate(struct key *, const void *, size_t);
22static void request_key_auth_describe(const struct key *, struct seq_file *);
David Howells04c567d2006-06-22 14:47:18 -070023static void request_key_auth_revoke(struct key *);
David Howells3e301482005-06-23 22:00:56 -070024static void request_key_auth_destroy(struct key *);
David Howellsb5f545c2006-01-08 01:02:47 -080025static long request_key_auth_read(const struct key *, char __user *, size_t);
David Howells3e301482005-06-23 22:00:56 -070026
27/*
28 * the request-key authorisation key type definition
29 */
30struct key_type key_type_request_key_auth = {
31 .name = ".request_key_auth",
32 .def_datalen = sizeof(struct request_key_auth),
33 .instantiate = request_key_auth_instantiate,
34 .describe = request_key_auth_describe,
David Howells04c567d2006-06-22 14:47:18 -070035 .revoke = request_key_auth_revoke,
David Howells3e301482005-06-23 22:00:56 -070036 .destroy = request_key_auth_destroy,
David Howellsb5f545c2006-01-08 01:02:47 -080037 .read = request_key_auth_read,
David Howells3e301482005-06-23 22:00:56 -070038};
39
40/*****************************************************************************/
41/*
David Howellsb5f545c2006-01-08 01:02:47 -080042 * instantiate a request-key authorisation key
David Howells3e301482005-06-23 22:00:56 -070043 */
44static int request_key_auth_instantiate(struct key *key,
45 const void *data,
46 size_t datalen)
47{
David Howellsb5f545c2006-01-08 01:02:47 -080048 key->payload.data = (struct request_key_auth *) data;
49 return 0;
David Howells3e301482005-06-23 22:00:56 -070050
51} /* end request_key_auth_instantiate() */
52
53/*****************************************************************************/
54/*
David Howellsb5f545c2006-01-08 01:02:47 -080055 * reading a request-key authorisation key retrieves the callout information
David Howells3e301482005-06-23 22:00:56 -070056 */
57static void request_key_auth_describe(const struct key *key,
58 struct seq_file *m)
59{
60 struct request_key_auth *rka = key->payload.data;
61
62 seq_puts(m, "key:");
63 seq_puts(m, key->description);
David Howellsb5f545c2006-01-08 01:02:47 -080064 seq_printf(m, " pid:%d ci:%zu", rka->pid, strlen(rka->callout_info));
David Howells3e301482005-06-23 22:00:56 -070065
66} /* end request_key_auth_describe() */
67
68/*****************************************************************************/
69/*
David Howellsb5f545c2006-01-08 01:02:47 -080070 * read the callout_info data
71 * - the key's semaphore is read-locked
72 */
73static long request_key_auth_read(const struct key *key,
74 char __user *buffer, size_t buflen)
75{
76 struct request_key_auth *rka = key->payload.data;
77 size_t datalen;
78 long ret;
79
80 datalen = strlen(rka->callout_info);
81 ret = datalen;
82
83 /* we can return the data as is */
84 if (buffer && buflen > 0) {
85 if (buflen > datalen)
86 buflen = datalen;
87
88 if (copy_to_user(buffer, rka->callout_info, buflen) != 0)
89 ret = -EFAULT;
90 }
91
92 return ret;
93
94} /* end request_key_auth_read() */
95
96/*****************************************************************************/
97/*
David Howells04c567d2006-06-22 14:47:18 -070098 * handle revocation of an authorisation token key
99 * - called with the key sem write-locked
100 */
101static void request_key_auth_revoke(struct key *key)
102{
103 struct request_key_auth *rka = key->payload.data;
104
105 kenter("{%d}", key->serial);
106
107 if (rka->context) {
108 put_task_struct(rka->context);
109 rka->context = NULL;
110 }
111
112} /* end request_key_auth_revoke() */
113
114/*****************************************************************************/
115/*
David Howells3e301482005-06-23 22:00:56 -0700116 * destroy an instantiation authorisation token key
117 */
118static void request_key_auth_destroy(struct key *key)
119{
120 struct request_key_auth *rka = key->payload.data;
121
122 kenter("{%d}", key->serial);
123
David Howells04c567d2006-06-22 14:47:18 -0700124 if (rka->context) {
125 put_task_struct(rka->context);
126 rka->context = NULL;
127 }
128
David Howells3e301482005-06-23 22:00:56 -0700129 key_put(rka->target_key);
David Howells76181c12007-10-16 23:29:46 -0700130 kfree(rka->callout_info);
David Howells74fd92c2005-10-07 15:01:09 +0100131 kfree(rka);
David Howells3e301482005-06-23 22:00:56 -0700132
133} /* end request_key_auth_destroy() */
134
135/*****************************************************************************/
136/*
David Howellsb5f545c2006-01-08 01:02:47 -0800137 * create an authorisation token for /sbin/request-key or whoever to gain
138 * access to the caller's security data
David Howells3e301482005-06-23 22:00:56 -0700139 */
David Howellsb5f545c2006-01-08 01:02:47 -0800140struct key *request_key_auth_new(struct key *target, const char *callout_info)
David Howells3e301482005-06-23 22:00:56 -0700141{
David Howellsb5f545c2006-01-08 01:02:47 -0800142 struct request_key_auth *rka, *irka;
143 struct key *authkey = NULL;
David Howells3e301482005-06-23 22:00:56 -0700144 char desc[20];
145 int ret;
146
147 kenter("%d,", target->serial);
148
David Howellsb5f545c2006-01-08 01:02:47 -0800149 /* allocate a auth record */
150 rka = kmalloc(sizeof(*rka), GFP_KERNEL);
151 if (!rka) {
152 kleave(" = -ENOMEM");
153 return ERR_PTR(-ENOMEM);
David Howells3e301482005-06-23 22:00:56 -0700154 }
David Howells76181c12007-10-16 23:29:46 -0700155 rka->callout_info = kmalloc(strlen(callout_info) + 1, GFP_KERNEL);
156 if (!rka->callout_info) {
157 kleave(" = -ENOMEM");
158 kfree(rka);
159 return ERR_PTR(-ENOMEM);
160 }
David Howells3e301482005-06-23 22:00:56 -0700161
David Howellsb5f545c2006-01-08 01:02:47 -0800162 /* see if the calling process is already servicing the key request of
163 * another process */
164 if (current->request_key_auth) {
165 /* it is - use that instantiation context here too */
David Howells04c567d2006-06-22 14:47:18 -0700166 down_read(&current->request_key_auth->sem);
167
168 /* if the auth key has been revoked, then the key we're
169 * servicing is already instantiated */
170 if (test_bit(KEY_FLAG_REVOKED,
171 &current->request_key_auth->flags))
172 goto auth_key_revoked;
173
David Howellsb5f545c2006-01-08 01:02:47 -0800174 irka = current->request_key_auth->payload.data;
175 rka->context = irka->context;
176 rka->pid = irka->pid;
David Howells04c567d2006-06-22 14:47:18 -0700177 get_task_struct(rka->context);
178
179 up_read(&current->request_key_auth->sem);
David Howellsb5f545c2006-01-08 01:02:47 -0800180 }
181 else {
182 /* it isn't - use this process as the context */
183 rka->context = current;
184 rka->pid = current->pid;
David Howells04c567d2006-06-22 14:47:18 -0700185 get_task_struct(rka->context);
David Howellsb5f545c2006-01-08 01:02:47 -0800186 }
187
188 rka->target_key = key_get(target);
David Howells76181c12007-10-16 23:29:46 -0700189 strcpy(rka->callout_info, callout_info);
David Howellsb5f545c2006-01-08 01:02:47 -0800190
David Howells3e301482005-06-23 22:00:56 -0700191 /* allocate the auth key */
192 sprintf(desc, "%x", target->serial);
193
David Howellsb5f545c2006-01-08 01:02:47 -0800194 authkey = key_alloc(&key_type_request_key_auth, desc,
Michael LeMayd7200242006-06-22 14:47:17 -0700195 current->fsuid, current->fsgid, current,
David Howellsb5f545c2006-01-08 01:02:47 -0800196 KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH |
David Howells7e047ef2006-06-26 00:24:50 -0700197 KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA);
David Howellsb5f545c2006-01-08 01:02:47 -0800198 if (IS_ERR(authkey)) {
199 ret = PTR_ERR(authkey);
200 goto error_alloc;
David Howells3e301482005-06-23 22:00:56 -0700201 }
202
203 /* construct and attach to the keyring */
David Howellsb5f545c2006-01-08 01:02:47 -0800204 ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL);
205 if (ret < 0)
206 goto error_inst;
David Howells3e301482005-06-23 22:00:56 -0700207
David Howells04c567d2006-06-22 14:47:18 -0700208 kleave(" = {%d}", authkey->serial);
David Howellsb5f545c2006-01-08 01:02:47 -0800209 return authkey;
210
David Howells04c567d2006-06-22 14:47:18 -0700211auth_key_revoked:
212 up_read(&current->request_key_auth->sem);
David Howells76181c12007-10-16 23:29:46 -0700213 kfree(rka->callout_info);
David Howells04c567d2006-06-22 14:47:18 -0700214 kfree(rka);
215 kleave("= -EKEYREVOKED");
216 return ERR_PTR(-EKEYREVOKED);
217
David Howellsb5f545c2006-01-08 01:02:47 -0800218error_inst:
219 key_revoke(authkey);
220 key_put(authkey);
221error_alloc:
222 key_put(rka->target_key);
David Howells76181c12007-10-16 23:29:46 -0700223 kfree(rka->callout_info);
David Howellsb5f545c2006-01-08 01:02:47 -0800224 kfree(rka);
225 kleave("= %d", ret);
226 return ERR_PTR(ret);
David Howells3e301482005-06-23 22:00:56 -0700227
228} /* end request_key_auth_new() */
229
230/*****************************************************************************/
231/*
David Howellsb5f545c2006-01-08 01:02:47 -0800232 * see if an authorisation key is associated with a particular key
233 */
234static int key_get_instantiation_authkey_match(const struct key *key,
235 const void *_id)
236{
237 struct request_key_auth *rka = key->payload.data;
238 key_serial_t id = (key_serial_t)(unsigned long) _id;
239
240 return rka->target_key->serial == id;
241
242} /* end key_get_instantiation_authkey_match() */
243
244/*****************************************************************************/
245/*
David Howells3e301482005-06-23 22:00:56 -0700246 * get the authorisation key for instantiation of a specific key if attached to
247 * the current process's keyrings
248 * - this key is inserted into a keyring and that is set as /sbin/request-key's
249 * session keyring
250 * - a target_id of zero specifies any valid token
251 */
252struct key *key_get_instantiation_authkey(key_serial_t target_id)
253{
David Howellsb5f545c2006-01-08 01:02:47 -0800254 struct key *authkey;
255 key_ref_t authkey_ref;
David Howells3e301482005-06-23 22:00:56 -0700256
David Howellsb5f545c2006-01-08 01:02:47 -0800257 authkey_ref = search_process_keyrings(
258 &key_type_request_key_auth,
259 (void *) (unsigned long) target_id,
260 key_get_instantiation_authkey_match,
261 current);
David Howells3e301482005-06-23 22:00:56 -0700262
David Howellsb5f545c2006-01-08 01:02:47 -0800263 if (IS_ERR(authkey_ref)) {
264 authkey = ERR_PTR(PTR_ERR(authkey_ref));
265 goto error;
266 }
David Howells3e301482005-06-23 22:00:56 -0700267
David Howellsb5f545c2006-01-08 01:02:47 -0800268 authkey = key_ref_to_ptr(authkey_ref);
269 if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) {
270 key_put(authkey);
271 authkey = ERR_PTR(-EKEYREVOKED);
272 }
David Howells3e301482005-06-23 22:00:56 -0700273
David Howellsb5f545c2006-01-08 01:02:47 -0800274error:
275 return authkey;
David Howells3e301482005-06-23 22:00:56 -0700276
277} /* end key_get_instantiation_authkey() */