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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 strlcpy(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}
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 __user *, 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 __user *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 if (copy_to_user(buffer, rka->callout_info, buflen) != 0)
101 ret = -EFAULT;
102 }
103
104 return ret;
105}
106
107static void free_request_key_auth(struct request_key_auth *rka)
108{
109 if (!rka)
110 return;
111 key_put(rka->target_key);
112 key_put(rka->dest_keyring);
113 if (rka->cred)
114 put_cred(rka->cred);
115 kfree(rka->callout_info);
116 kfree(rka);
117}
118
119/*
120 * Dispose of the request_key_auth record under RCU conditions
121 */
122static void request_key_auth_rcu_disposal(struct rcu_head *rcu)
123{
124 struct request_key_auth *rka =
125 container_of(rcu, struct request_key_auth, rcu);
126
127 free_request_key_auth(rka);
128}
129
130/*
131 * Handle revocation of an authorisation token key.
132 *
133 * Called with the key sem write-locked.
134 */
135static void request_key_auth_revoke(struct key *key)
136{
137 struct request_key_auth *rka = dereference_key_locked(key);
138
139 kenter("{%d}", key->serial);
140 rcu_assign_keypointer(key, NULL);
141 call_rcu(&rka->rcu, request_key_auth_rcu_disposal);
142}
143
144/*
145 * Destroy an instantiation authorisation token key.
146 */
147static void request_key_auth_destroy(struct key *key)
148{
149 struct request_key_auth *rka = rcu_access_pointer(key->payload.rcu_data0);
150
151 kenter("{%d}", key->serial);
152 if (rka) {
153 rcu_assign_keypointer(key, NULL);
154 call_rcu(&rka->rcu, request_key_auth_rcu_disposal);
155 }
156}
157
158/*
159 * Create an authorisation token for /sbin/request-key or whoever to gain
160 * access to the caller's security data.
161 */
162struct key *request_key_auth_new(struct key *target, const char *op,
163 const void *callout_info, size_t callout_len,
164 struct key *dest_keyring)
165{
166 struct request_key_auth *rka, *irka;
167 const struct cred *cred = current_cred();
168 struct key *authkey = NULL;
169 char desc[20];
170 int ret = -ENOMEM;
171
172 kenter("%d,", target->serial);
173
174 /* allocate a auth record */
175 rka = kzalloc(sizeof(*rka), GFP_KERNEL);
176 if (!rka)
177 goto error;
178 rka->callout_info = kmemdup(callout_info, callout_len, GFP_KERNEL);
179 if (!rka->callout_info)
180 goto error_free_rka;
181 rka->callout_len = callout_len;
182 strlcpy(rka->op, op, sizeof(rka->op));
183
184 /* see if the calling process is already servicing the key request of
185 * another process */
186 if (cred->request_key_auth) {
187 /* it is - use that instantiation context here too */
188 down_read(&cred->request_key_auth->sem);
189
190 /* if the auth key has been revoked, then the key we're
191 * servicing is already instantiated */
192 if (test_bit(KEY_FLAG_REVOKED,
193 &cred->request_key_auth->flags)) {
194 up_read(&cred->request_key_auth->sem);
195 ret = -EKEYREVOKED;
196 goto error_free_rka;
197 }
198
199 irka = cred->request_key_auth->payload.data[0];
200 rka->cred = get_cred(irka->cred);
201 rka->pid = irka->pid;
202
203 up_read(&cred->request_key_auth->sem);
204 }
205 else {
206 /* it isn't - use this process as the context */
207 rka->cred = get_cred(cred);
208 rka->pid = current->pid;
209 }
210
211 rka->target_key = key_get(target);
212 rka->dest_keyring = key_get(dest_keyring);
213
214 /* allocate the auth key */
215 sprintf(desc, "%x", target->serial);
216
217 authkey = key_alloc(&key_type_request_key_auth, desc,
218 cred->fsuid, cred->fsgid, cred,
219 KEY_POS_VIEW | KEY_POS_READ | KEY_POS_SEARCH | KEY_POS_LINK |
220 KEY_USR_VIEW, KEY_ALLOC_NOT_IN_QUOTA, NULL);
221 if (IS_ERR(authkey)) {
222 ret = PTR_ERR(authkey);
223 goto error_free_rka;
224 }
225
226 /* construct the auth key */
227 ret = key_instantiate_and_link(authkey, rka, 0, NULL, NULL);
228 if (ret < 0)
229 goto error_put_authkey;
230
231 kleave(" = {%d,%d}", authkey->serial, refcount_read(&authkey->usage));
232 return authkey;
233
234error_put_authkey:
235 key_put(authkey);
236error_free_rka:
237 free_request_key_auth(rka);
238error:
239 kleave("= %d", ret);
240 return ERR_PTR(ret);
241}
242
243/*
244 * Search the current process's keyrings for the authorisation key for
245 * instantiation of a key.
246 */
247struct key *key_get_instantiation_authkey(key_serial_t target_id)
248{
249 char description[16];
250 struct keyring_search_context ctx = {
251 .index_key.type = &key_type_request_key_auth,
252 .index_key.description = description,
253 .cred = current_cred(),
254 .match_data.cmp = key_default_cmp,
255 .match_data.raw_data = description,
256 .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
257 .flags = (KEYRING_SEARCH_DO_STATE_CHECK |
258 KEYRING_SEARCH_RECURSE),
259 };
260 struct key *authkey;
261 key_ref_t authkey_ref;
262
263 ctx.index_key.desc_len = sprintf(description, "%x", target_id);
264
265 rcu_read_lock();
266 authkey_ref = search_process_keyrings_rcu(&ctx);
267 rcu_read_unlock();
268
269 if (IS_ERR(authkey_ref)) {
270 authkey = ERR_CAST(authkey_ref);
271 if (authkey == ERR_PTR(-EAGAIN))
272 authkey = ERR_PTR(-ENOKEY);
273 goto error;
274 }
275
276 authkey = key_ref_to_ptr(authkey_ref);
277 if (test_bit(KEY_FLAG_REVOKED, &authkey->flags)) {
278 key_put(authkey);
279 authkey = ERR_PTR(-EKEYREVOKED);
280 }
281
282error:
283 return authkey;
284}