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David Howells973c9f42011-01-20 16:38:33 +00001/* Request key authorisation token key definition.
David Howells3e301482005-06-23 22:00:56 -07002 *
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 *
Randy Dunlapd410fa42011-05-19 15:59:38 -070011 * See Documentation/security/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>
Robert P. J. Dayfdb89bc2008-04-29 01:01:32 -070018#include <linux/slab.h>
David Howellsb5f545c2006-01-08 01:02:47 -080019#include <asm/uaccess.h>
David Howells3e301482005-06-23 22:00:56 -070020#include "internal.h"
21
22static int request_key_auth_instantiate(struct key *, const void *, size_t);
23static void request_key_auth_describe(const struct key *, struct seq_file *);
David Howells04c567d2006-06-22 14:47:18 -070024static void request_key_auth_revoke(struct key *);
David Howells3e301482005-06-23 22:00:56 -070025static void request_key_auth_destroy(struct key *);
David Howellsb5f545c2006-01-08 01:02:47 -080026static long request_key_auth_read(const struct key *, char __user *, size_t);
David Howells3e301482005-06-23 22:00:56 -070027
28/*
David Howells973c9f42011-01-20 16:38:33 +000029 * The request-key authorisation key type definition.
David Howells3e301482005-06-23 22:00:56 -070030 */
31struct 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,
David Howells04c567d2006-06-22 14:47:18 -070036 .revoke = request_key_auth_revoke,
David Howells3e301482005-06-23 22:00:56 -070037 .destroy = request_key_auth_destroy,
David Howellsb5f545c2006-01-08 01:02:47 -080038 .read = request_key_auth_read,
David Howells3e301482005-06-23 22:00:56 -070039};
40
David Howells3e301482005-06-23 22:00:56 -070041/*
David Howells973c9f42011-01-20 16:38:33 +000042 * 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 Howellsa8b17ed2011-01-20 16:38:27 +000050}
David Howells3e301482005-06-23 22:00:56 -070051
David Howells3e301482005-06-23 22:00:56 -070052/*
David Howells973c9f42011-01-20 16:38:33 +000053 * Describe an authorisation token.
David Howells3e301482005-06-23 22:00:56 -070054 */
55static void request_key_auth_describe(const struct key *key,
56 struct seq_file *m)
57{
58 struct request_key_auth *rka = key->payload.data;
59
60 seq_puts(m, "key:");
61 seq_puts(m, key->description);
David Howells78b72802011-03-11 17:57:23 +000062 if (key_is_instantiated(key))
63 seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len);
David Howellsa8b17ed2011-01-20 16:38:27 +000064}
David Howells3e301482005-06-23 22:00:56 -070065
David Howells3e301482005-06-23 22:00:56 -070066/*
David Howells973c9f42011-01-20 16:38:33 +000067 * Read the callout_info data (retrieves the callout information).
David Howellsb5f545c2006-01-08 01:02:47 -080068 * - the key's semaphore is read-locked
69 */
70static long request_key_auth_read(const struct key *key,
71 char __user *buffer, size_t buflen)
72{
73 struct request_key_auth *rka = key->payload.data;
74 size_t datalen;
75 long ret;
76
David Howells4a38e122008-04-29 01:01:24 -070077 datalen = rka->callout_len;
David Howellsb5f545c2006-01-08 01:02:47 -080078 ret = datalen;
79
80 /* we can return the data as is */
81 if (buffer && buflen > 0) {
82 if (buflen > datalen)
83 buflen = datalen;
84
85 if (copy_to_user(buffer, rka->callout_info, buflen) != 0)
86 ret = -EFAULT;
87 }
88
89 return ret;
David Howellsa8b17ed2011-01-20 16:38:27 +000090}
David Howellsb5f545c2006-01-08 01:02:47 -080091
David Howellsb5f545c2006-01-08 01:02:47 -080092/*
David Howells973c9f42011-01-20 16:38:33 +000093 * Handle revocation of an authorisation token key.
94 *
95 * Called with the key sem write-locked.
David Howells04c567d2006-06-22 14:47:18 -070096 */
97static void request_key_auth_revoke(struct key *key)
98{
99 struct request_key_auth *rka = key->payload.data;
100
101 kenter("{%d}", key->serial);
102
David Howellsd84f4f92008-11-14 10:39:23 +1100103 if (rka->cred) {
104 put_cred(rka->cred);
105 rka->cred = NULL;
David Howells04c567d2006-06-22 14:47:18 -0700106 }
David Howellsa8b17ed2011-01-20 16:38:27 +0000107}
David Howells04c567d2006-06-22 14:47:18 -0700108
David Howells04c567d2006-06-22 14:47:18 -0700109/*
David Howells973c9f42011-01-20 16:38:33 +0000110 * Destroy an instantiation authorisation token key.
David Howells3e301482005-06-23 22:00:56 -0700111 */
112static void request_key_auth_destroy(struct key *key)
113{
114 struct request_key_auth *rka = key->payload.data;
115
116 kenter("{%d}", key->serial);
117
David Howellsd84f4f92008-11-14 10:39:23 +1100118 if (rka->cred) {
119 put_cred(rka->cred);
120 rka->cred = NULL;
David Howells04c567d2006-06-22 14:47:18 -0700121 }
122
David Howells3e301482005-06-23 22:00:56 -0700123 key_put(rka->target_key);
David Howells8bbf49762008-11-14 10:39:14 +1100124 key_put(rka->dest_keyring);
David Howells76181c12007-10-16 23:29:46 -0700125 kfree(rka->callout_info);
David Howells74fd92c2005-10-07 15:01:09 +0100126 kfree(rka);
David Howellsa8b17ed2011-01-20 16:38:27 +0000127}
David Howells3e301482005-06-23 22:00:56 -0700128
David Howells3e301482005-06-23 22:00:56 -0700129/*
David Howells973c9f42011-01-20 16:38:33 +0000130 * Create an authorisation token for /sbin/request-key or whoever to gain
131 * access to the caller's security data.
David Howells3e301482005-06-23 22:00:56 -0700132 */
David Howells4a38e122008-04-29 01:01:24 -0700133struct key *request_key_auth_new(struct key *target, const void *callout_info,
David Howells8bbf49762008-11-14 10:39:14 +1100134 size_t callout_len, struct key *dest_keyring)
David Howells3e301482005-06-23 22:00:56 -0700135{
David Howellsb5f545c2006-01-08 01:02:47 -0800136 struct request_key_auth *rka, *irka;
David Howellsd84f4f92008-11-14 10:39:23 +1100137 const struct cred *cred = current->cred;
David Howellsb5f545c2006-01-08 01:02:47 -0800138 struct key *authkey = NULL;
David Howells3e301482005-06-23 22:00:56 -0700139 char desc[20];
140 int ret;
141
142 kenter("%d,", target->serial);
143
David Howellsb5f545c2006-01-08 01:02:47 -0800144 /* allocate a auth record */
145 rka = kmalloc(sizeof(*rka), GFP_KERNEL);
146 if (!rka) {
147 kleave(" = -ENOMEM");
148 return ERR_PTR(-ENOMEM);
David Howells3e301482005-06-23 22:00:56 -0700149 }
David Howells4a38e122008-04-29 01:01:24 -0700150 rka->callout_info = kmalloc(callout_len, GFP_KERNEL);
David Howells76181c12007-10-16 23:29:46 -0700151 if (!rka->callout_info) {
152 kleave(" = -ENOMEM");
153 kfree(rka);
154 return ERR_PTR(-ENOMEM);
155 }
David Howells3e301482005-06-23 22:00:56 -0700156
David Howellsb5f545c2006-01-08 01:02:47 -0800157 /* see if the calling process is already servicing the key request of
158 * another process */
David Howellsd84f4f92008-11-14 10:39:23 +1100159 if (cred->request_key_auth) {
David Howellsb5f545c2006-01-08 01:02:47 -0800160 /* it is - use that instantiation context here too */
David Howellsd84f4f92008-11-14 10:39:23 +1100161 down_read(&cred->request_key_auth->sem);
David Howells04c567d2006-06-22 14:47:18 -0700162
163 /* if the auth key has been revoked, then the key we're
164 * servicing is already instantiated */
David Howellsd84f4f92008-11-14 10:39:23 +1100165 if (test_bit(KEY_FLAG_REVOKED, &cred->request_key_auth->flags))
David Howells04c567d2006-06-22 14:47:18 -0700166 goto auth_key_revoked;
167
David Howellsd84f4f92008-11-14 10:39:23 +1100168 irka = cred->request_key_auth->payload.data;
169 rka->cred = get_cred(irka->cred);
David Howellsb5f545c2006-01-08 01:02:47 -0800170 rka->pid = irka->pid;
David Howells04c567d2006-06-22 14:47:18 -0700171
David Howellsd84f4f92008-11-14 10:39:23 +1100172 up_read(&cred->request_key_auth->sem);
David Howellsb5f545c2006-01-08 01:02:47 -0800173 }
174 else {
175 /* it isn't - use this process as the context */
David Howellsd84f4f92008-11-14 10:39:23 +1100176 rka->cred = get_cred(cred);
David Howellsb5f545c2006-01-08 01:02:47 -0800177 rka->pid = current->pid;
178 }
179
180 rka->target_key = key_get(target);
David Howells8bbf49762008-11-14 10:39:14 +1100181 rka->dest_keyring = key_get(dest_keyring);
David Howells4a38e122008-04-29 01:01:24 -0700182 memcpy(rka->callout_info, callout_info, callout_len);
183 rka->callout_len = callout_len;
David Howellsb5f545c2006-01-08 01:02:47 -0800184
David Howells3e301482005-06-23 22:00:56 -0700185 /* allocate the auth key */
186 sprintf(desc, "%x", target->serial);
187
David Howellsb5f545c2006-01-08 01:02:47 -0800188 authkey = key_alloc(&key_type_request_key_auth, desc,
David Howellsd84f4f92008-11-14 10:39:23 +1100189 cred->fsuid, cred->fsgid, cred,
David Howellsb5f545c2006-01-08 01:02:47 -0800190 KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH |
David Howells7e047ef2006-06-26 00:24:50 -0700191 KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA);
David Howellsb5f545c2006-01-08 01:02:47 -0800192 if (IS_ERR(authkey)) {
193 ret = PTR_ERR(authkey);
194 goto error_alloc;
David Howells3e301482005-06-23 22:00:56 -0700195 }
196
David Howellsd84f4f92008-11-14 10:39:23 +1100197 /* construct the auth key */
David Howellsb5f545c2006-01-08 01:02:47 -0800198 ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL);
199 if (ret < 0)
200 goto error_inst;
David Howells3e301482005-06-23 22:00:56 -0700201
David Howellsd84f4f92008-11-14 10:39:23 +1100202 kleave(" = {%d,%d}", authkey->serial, atomic_read(&authkey->usage));
David Howellsb5f545c2006-01-08 01:02:47 -0800203 return authkey;
204
David Howells04c567d2006-06-22 14:47:18 -0700205auth_key_revoked:
David Howellsd84f4f92008-11-14 10:39:23 +1100206 up_read(&cred->request_key_auth->sem);
David Howells76181c12007-10-16 23:29:46 -0700207 kfree(rka->callout_info);
David Howells04c567d2006-06-22 14:47:18 -0700208 kfree(rka);
209 kleave("= -EKEYREVOKED");
210 return ERR_PTR(-EKEYREVOKED);
211
David Howellsb5f545c2006-01-08 01:02:47 -0800212error_inst:
213 key_revoke(authkey);
214 key_put(authkey);
215error_alloc:
216 key_put(rka->target_key);
David Howells8bbf49762008-11-14 10:39:14 +1100217 key_put(rka->dest_keyring);
David Howells76181c12007-10-16 23:29:46 -0700218 kfree(rka->callout_info);
David Howellsb5f545c2006-01-08 01:02:47 -0800219 kfree(rka);
220 kleave("= %d", ret);
221 return ERR_PTR(ret);
David Howellsa8b17ed2011-01-20 16:38:27 +0000222}
David Howells3e301482005-06-23 22:00:56 -0700223
David Howells3e301482005-06-23 22:00:56 -0700224/*
David Howells973c9f42011-01-20 16:38:33 +0000225 * See if an authorisation key is associated with a particular key.
David Howellsb5f545c2006-01-08 01:02:47 -0800226 */
227static int key_get_instantiation_authkey_match(const struct key *key,
228 const void *_id)
229{
230 struct request_key_auth *rka = key->payload.data;
231 key_serial_t id = (key_serial_t)(unsigned long) _id;
232
233 return rka->target_key->serial == id;
David Howellsa8b17ed2011-01-20 16:38:27 +0000234}
David Howellsb5f545c2006-01-08 01:02:47 -0800235
David Howellsb5f545c2006-01-08 01:02:47 -0800236/*
David Howells973c9f42011-01-20 16:38:33 +0000237 * Search the current process's keyrings for the authorisation key for
238 * instantiation of a key.
David Howells3e301482005-06-23 22:00:56 -0700239 */
240struct key *key_get_instantiation_authkey(key_serial_t target_id)
241{
David Howellsd84f4f92008-11-14 10:39:23 +1100242 const struct cred *cred = current_cred();
David Howellsb5f545c2006-01-08 01:02:47 -0800243 struct key *authkey;
244 key_ref_t authkey_ref;
David Howells3e301482005-06-23 22:00:56 -0700245
David Howellsb5f545c2006-01-08 01:02:47 -0800246 authkey_ref = search_process_keyrings(
247 &key_type_request_key_auth,
248 (void *) (unsigned long) target_id,
249 key_get_instantiation_authkey_match,
David Howellsd84f4f92008-11-14 10:39:23 +1100250 cred);
David Howells3e301482005-06-23 22:00:56 -0700251
David Howellsb5f545c2006-01-08 01:02:47 -0800252 if (IS_ERR(authkey_ref)) {
David Howellse231c2e2008-02-07 00:15:26 -0800253 authkey = ERR_CAST(authkey_ref);
David Howells4d674312011-06-13 22:33:52 +0100254 if (authkey == ERR_PTR(-EAGAIN))
255 authkey = ERR_PTR(-ENOKEY);
David Howellsb5f545c2006-01-08 01:02:47 -0800256 goto error;
257 }
David Howells3e301482005-06-23 22:00:56 -0700258
David Howellsb5f545c2006-01-08 01:02:47 -0800259 authkey = key_ref_to_ptr(authkey_ref);
260 if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) {
261 key_put(authkey);
262 authkey = ERR_PTR(-EKEYREVOKED);
263 }
David Howells3e301482005-06-23 22:00:56 -0700264
David Howellsb5f545c2006-01-08 01:02:47 -0800265error:
266 return authkey;
David Howellsa8b17ed2011-01-20 16:38:27 +0000267}