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1/* Request key authorisation token key definition.
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.
10 *
11 * See Documentation/security/keys-request-key.txt
12 */
13
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>
20#include "internal.h"
21#include <keys/user-type.h>
22
23static int request_key_auth_preparse(struct key_preparsed_payload *);
24static void request_key_auth_free_preparse(struct key_preparsed_payload *);
25static int request_key_auth_instantiate(struct key *,
26 struct key_preparsed_payload *);
27static void request_key_auth_describe(const struct key *, struct seq_file *);
28static void request_key_auth_revoke(struct key *);
29static void request_key_auth_destroy(struct key *);
30static long request_key_auth_read(const struct key *, char __user *, size_t);
31
32/*
33 * The request-key authorisation key type definition.
34 */
35struct 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,
45};
46
47static int request_key_auth_preparse(struct key_preparsed_payload *prep)
48{
49 return 0;
50}
51
52static void request_key_auth_free_preparse(struct key_preparsed_payload *prep)
53{
54}
55
56/*
57 * Instantiate a request-key authorisation key.
58 */
59static int request_key_auth_instantiate(struct key *key,
60 struct key_preparsed_payload *prep)
61{
62 key->payload.data[0] = (struct request_key_auth *)prep->data;
63 return 0;
64}
65
66/*
67 * Describe an authorisation token.
68 */
69static void request_key_auth_describe(const struct key *key,
70 struct seq_file *m)
71{
72 struct request_key_auth *rka = key->payload.data[0];
73
74 seq_puts(m, "key:");
75 seq_puts(m, key->description);
76 if (key_is_instantiated(key))
77 seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len);
78}
79
80/*
81 * Read the callout_info data (retrieves the callout information).
82 * - the key's semaphore is read-locked
83 */
84static long request_key_auth_read(const struct key *key,
85 char __user *buffer, size_t buflen)
86{
87 struct request_key_auth *rka = key->payload.data[0];
88 size_t datalen;
89 long ret;
90
91 datalen = rka->callout_len;
92 ret = datalen;
93
94 /* we can return the data as is */
95 if (buffer && buflen > 0) {
96 if (buflen > datalen)
97 buflen = datalen;
98
99 if (copy_to_user(buffer, rka->callout_info, buflen) != 0)
100 ret = -EFAULT;
101 }
102
103 return ret;
104}
105
106/*
107 * Handle revocation of an authorisation token key.
108 *
109 * Called with the key sem write-locked.
110 */
111static void request_key_auth_revoke(struct key *key)
112{
113 struct request_key_auth *rka = key->payload.data[0];
114
115 kenter("{%d}", key->serial);
116
117 if (rka->cred) {
118 put_cred(rka->cred);
119 rka->cred = NULL;
120 }
121}
122
123/*
124 * Destroy an instantiation authorisation token key.
125 */
126static void request_key_auth_destroy(struct key *key)
127{
128 struct request_key_auth *rka = key->payload.data[0];
129
130 kenter("{%d}", key->serial);
131
132 if (rka->cred) {
133 put_cred(rka->cred);
134 rka->cred = NULL;
135 }
136
137 key_put(rka->target_key);
138 key_put(rka->dest_keyring);
139 kfree(rka->callout_info);
140 kfree(rka);
141}
142
143/*
144 * Create an authorisation token for /sbin/request-key or whoever to gain
145 * access to the caller's security data.
146 */
147struct key *request_key_auth_new(struct key *target, const void *callout_info,
148 size_t callout_len, struct key *dest_keyring)
149{
150 struct request_key_auth *rka, *irka;
151 const struct cred *cred = current->cred;
152 struct key *authkey = NULL;
153 char desc[20];
154 int ret;
155
156 kenter("%d,", target->serial);
157
158 /* allocate a auth record */
159 rka = kmalloc(sizeof(*rka), GFP_KERNEL);
160 if (!rka) {
161 kleave(" = -ENOMEM");
162 return ERR_PTR(-ENOMEM);
163 }
164 rka->callout_info = kmalloc(callout_len, GFP_KERNEL);
165 if (!rka->callout_info) {
166 kleave(" = -ENOMEM");
167 kfree(rka);
168 return ERR_PTR(-ENOMEM);
169 }
170
171 /* see if the calling process is already servicing the key request of
172 * another process */
173 if (cred->request_key_auth) {
174 /* it is - use that instantiation context here too */
175 down_read(&cred->request_key_auth->sem);
176
177 /* if the auth key has been revoked, then the key we're
178 * servicing is already instantiated */
179 if (test_bit(KEY_FLAG_REVOKED, &cred->request_key_auth->flags))
180 goto auth_key_revoked;
181
182 irka = cred->request_key_auth->payload.data[0];
183 rka->cred = get_cred(irka->cred);
184 rka->pid = irka->pid;
185
186 up_read(&cred->request_key_auth->sem);
187 }
188 else {
189 /* it isn't - use this process as the context */
190 rka->cred = get_cred(cred);
191 rka->pid = current->pid;
192 }
193
194 rka->target_key = key_get(target);
195 rka->dest_keyring = key_get(dest_keyring);
196 memcpy(rka->callout_info, callout_info, callout_len);
197 rka->callout_len = callout_len;
198
199 /* allocate the auth key */
200 sprintf(desc, "%x", target->serial);
201
202 authkey = key_alloc(&key_type_request_key_auth, desc,
203 cred->fsuid, cred->fsgid, cred,
204 KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH |
205 KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA);
206 if (IS_ERR(authkey)) {
207 ret = PTR_ERR(authkey);
208 goto error_alloc;
209 }
210
211 /* construct the auth key */
212 ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL);
213 if (ret < 0)
214 goto error_inst;
215
216 kleave(" = {%d,%d}", authkey->serial, atomic_read(&authkey->usage));
217 return authkey;
218
219auth_key_revoked:
220 up_read(&cred->request_key_auth->sem);
221 kfree(rka->callout_info);
222 kfree(rka);
223 kleave("= -EKEYREVOKED");
224 return ERR_PTR(-EKEYREVOKED);
225
226error_inst:
227 key_revoke(authkey);
228 key_put(authkey);
229error_alloc:
230 key_put(rka->target_key);
231 key_put(rka->dest_keyring);
232 kfree(rka->callout_info);
233 kfree(rka);
234 kleave("= %d", ret);
235 return ERR_PTR(ret);
236}
237
238/*
239 * Search the current process's keyrings for the authorisation key for
240 * instantiation of a key.
241 */
242struct key *key_get_instantiation_authkey(key_serial_t target_id)
243{
244 char description[16];
245 struct keyring_search_context ctx = {
246 .index_key.type = &key_type_request_key_auth,
247 .index_key.description = description,
248 .cred = current_cred(),
249 .match_data.cmp = key_default_cmp,
250 .match_data.raw_data = description,
251 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
252 .flags = KEYRING_SEARCH_DO_STATE_CHECK,
253 };
254 struct key *authkey;
255 key_ref_t authkey_ref;
256
257 sprintf(description, "%x", target_id);
258
259 authkey_ref = search_process_keyrings(&ctx);
260
261 if (IS_ERR(authkey_ref)) {
262 authkey = ERR_CAST(authkey_ref);
263 if (authkey == ERR_PTR(-EAGAIN))
264 authkey = ERR_PTR(-ENOKEY);
265 goto error;
266 }
267
268 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 }
273
274error:
275 return authkey;
276}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Request key authorisation token key definition.
3 *
4 * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 *
7 * See Documentation/security/keys/request-key.rst
8 */
9
10#include <linux/sched.h>
11#include <linux/err.h>
12#include <linux/seq_file.h>
13#include <linux/slab.h>
14#include <linux/uaccess.h>
15#include "internal.h"
16#include <keys/request_key_auth-type.h>
17
18static int request_key_auth_preparse(struct key_preparsed_payload *);
19static void request_key_auth_free_preparse(struct key_preparsed_payload *);
20static int request_key_auth_instantiate(struct key *,
21 struct key_preparsed_payload *);
22static void request_key_auth_describe(const struct key *, struct seq_file *);
23static void request_key_auth_revoke(struct key *);
24static void request_key_auth_destroy(struct key *);
25static long request_key_auth_read(const struct key *, char *, size_t);
26
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 .preparse = request_key_auth_preparse,
34 .free_preparse = request_key_auth_free_preparse,
35 .instantiate = request_key_auth_instantiate,
36 .describe = request_key_auth_describe,
37 .revoke = request_key_auth_revoke,
38 .destroy = request_key_auth_destroy,
39 .read = request_key_auth_read,
40};
41
42static int request_key_auth_preparse(struct key_preparsed_payload *prep)
43{
44 return 0;
45}
46
47static void request_key_auth_free_preparse(struct key_preparsed_payload *prep)
48{
49}
50
51/*
52 * Instantiate a request-key authorisation key.
53 */
54static int request_key_auth_instantiate(struct key *key,
55 struct key_preparsed_payload *prep)
56{
57 rcu_assign_keypointer(key, (struct request_key_auth *)prep->data);
58 return 0;
59}
60
61/*
62 * Describe an authorisation token.
63 */
64static void request_key_auth_describe(const struct key *key,
65 struct seq_file *m)
66{
67 struct request_key_auth *rka = dereference_key_rcu(key);
68
69 if (!rka)
70 return;
71
72 seq_puts(m, "key:");
73 seq_puts(m, key->description);
74 if (key_is_positive(key))
75 seq_printf(m, " pid:%d ci:%zu", rka->pid, rka->callout_len);
76}
77
78/*
79 * Read the callout_info data (retrieves the callout information).
80 * - the key's semaphore is read-locked
81 */
82static long request_key_auth_read(const struct key *key,
83 char *buffer, size_t buflen)
84{
85 struct request_key_auth *rka = dereference_key_locked(key);
86 size_t datalen;
87 long ret;
88
89 if (!rka)
90 return -EKEYREVOKED;
91
92 datalen = rka->callout_len;
93 ret = datalen;
94
95 /* we can return the data as is */
96 if (buffer && buflen > 0) {
97 if (buflen > datalen)
98 buflen = datalen;
99
100 memcpy(buffer, rka->callout_info, buflen);
101 }
102
103 return ret;
104}
105
106static void free_request_key_auth(struct request_key_auth *rka)
107{
108 if (!rka)
109 return;
110 key_put(rka->target_key);
111 key_put(rka->dest_keyring);
112 if (rka->cred)
113 put_cred(rka->cred);
114 kfree(rka->callout_info);
115 kfree(rka);
116}
117
118/*
119 * Dispose of the request_key_auth record under RCU conditions
120 */
121static void request_key_auth_rcu_disposal(struct rcu_head *rcu)
122{
123 struct request_key_auth *rka =
124 container_of(rcu, struct request_key_auth, rcu);
125
126 free_request_key_auth(rka);
127}
128
129/*
130 * Handle revocation of an authorisation token key.
131 *
132 * Called with the key sem write-locked.
133 */
134static void request_key_auth_revoke(struct key *key)
135{
136 struct request_key_auth *rka = dereference_key_locked(key);
137
138 kenter("{%d}", key->serial);
139 rcu_assign_keypointer(key, NULL);
140 call_rcu(&rka->rcu, request_key_auth_rcu_disposal);
141}
142
143/*
144 * Destroy an instantiation authorisation token key.
145 */
146static void request_key_auth_destroy(struct key *key)
147{
148 struct request_key_auth *rka = rcu_access_pointer(key->payload.rcu_data0);
149
150 kenter("{%d}", key->serial);
151 if (rka) {
152 rcu_assign_keypointer(key, NULL);
153 call_rcu(&rka->rcu, request_key_auth_rcu_disposal);
154 }
155}
156
157/*
158 * Create an authorisation token for /sbin/request-key or whoever to gain
159 * access to the caller's security data.
160 */
161struct key *request_key_auth_new(struct key *target, const char *op,
162 const void *callout_info, size_t callout_len,
163 struct key *dest_keyring)
164{
165 struct request_key_auth *rka, *irka;
166 const struct cred *cred = current_cred();
167 struct key *authkey = NULL;
168 char desc[20];
169 int ret = -ENOMEM;
170
171 kenter("%d,", target->serial);
172
173 /* allocate a auth record */
174 rka = kzalloc(sizeof(*rka), GFP_KERNEL);
175 if (!rka)
176 goto error;
177 rka->callout_info = kmemdup(callout_info, callout_len, GFP_KERNEL);
178 if (!rka->callout_info)
179 goto error_free_rka;
180 rka->callout_len = callout_len;
181 strscpy(rka->op, op, sizeof(rka->op));
182
183 /* see if the calling process is already servicing the key request of
184 * another process */
185 if (cred->request_key_auth) {
186 /* it is - use that instantiation context here too */
187 down_read(&cred->request_key_auth->sem);
188
189 /* if the auth key has been revoked, then the key we're
190 * servicing is already instantiated */
191 if (test_bit(KEY_FLAG_REVOKED,
192 &cred->request_key_auth->flags)) {
193 up_read(&cred->request_key_auth->sem);
194 ret = -EKEYREVOKED;
195 goto error_free_rka;
196 }
197
198 irka = cred->request_key_auth->payload.data[0];
199 rka->cred = get_cred(irka->cred);
200 rka->pid = irka->pid;
201
202 up_read(&cred->request_key_auth->sem);
203 }
204 else {
205 /* it isn't - use this process as the context */
206 rka->cred = get_cred(cred);
207 rka->pid = current->pid;
208 }
209
210 rka->target_key = key_get(target);
211 rka->dest_keyring = key_get(dest_keyring);
212
213 /* allocate the auth key */
214 sprintf(desc, "%x", target->serial);
215
216 authkey = key_alloc(&key_type_request_key_auth, desc,
217 cred->fsuid, cred->fsgid, cred,
218 KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH | KEY_POS_LINK |
219 KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA, NULL);
220 if (IS_ERR(authkey)) {
221 ret = PTR_ERR(authkey);
222 goto error_free_rka;
223 }
224
225 /* construct the auth key */
226 ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL);
227 if (ret < 0)
228 goto error_put_authkey;
229
230 kleave(" = {%d,%d}", authkey->serial, refcount_read(&authkey->usage));
231 return authkey;
232
233error_put_authkey:
234 key_put(authkey);
235error_free_rka:
236 free_request_key_auth(rka);
237error:
238 kleave("= %d", ret);
239 return ERR_PTR(ret);
240}
241
242/*
243 * Search the current process's keyrings for the authorisation key for
244 * instantiation of a key.
245 */
246struct key *key_get_instantiation_authkey(key_serial_t target_id)
247{
248 char description[16];
249 struct keyring_search_context ctx = {
250 .index_key.type = &key_type_request_key_auth,
251 .index_key.description = description,
252 .cred = current_cred(),
253 .match_data.cmp = key_default_cmp,
254 .match_data.raw_data = description,
255 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
256 .flags = (KEYRING_SEARCH_DO_STATE_CHECK |
257 KEYRING_SEARCH_RECURSE),
258 };
259 struct key *authkey;
260 key_ref_t authkey_ref;
261
262 ctx.index_key.desc_len = sprintf(description, "%x", target_id);
263
264 rcu_read_lock();
265 authkey_ref = search_process_keyrings_rcu(&ctx);
266 rcu_read_unlock();
267
268 if (IS_ERR(authkey_ref)) {
269 authkey = ERR_CAST(authkey_ref);
270 if (authkey == ERR_PTR(-EAGAIN))
271 authkey = ERR_PTR(-ENOKEY);
272 goto error;
273 }
274
275 authkey = key_ref_to_ptr(authkey_ref);
276 if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) {
277 key_put(authkey);
278 authkey = ERR_PTR(-EKEYREVOKED);
279 }
280
281error:
282 return authkey;
283}