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1// SPDX-License-Identifier: GPL-2.0
2/* Copyright(c) 2018 Intel Corporation. All rights reserved. */
3
4#include <linux/module.h>
5#include <linux/device.h>
6#include <linux/ndctl.h>
7#include <linux/slab.h>
8#include <linux/io.h>
9#include <linux/mm.h>
10#include <linux/cred.h>
11#include <linux/key.h>
12#include <linux/key-type.h>
13#include <keys/user-type.h>
14#include <keys/encrypted-type.h>
15#include "nd-core.h"
16#include "nd.h"
17
18#define NVDIMM_BASE_KEY 0
19#define NVDIMM_NEW_KEY 1
20
21static bool key_revalidate = true;
22module_param(key_revalidate, bool, 0444);
23MODULE_PARM_DESC(key_revalidate, "Require key validation at init.");
24
25static const char zero_key[NVDIMM_PASSPHRASE_LEN];
26
27static void *key_data(struct key *key)
28{
29 struct encrypted_key_payload *epayload = dereference_key_locked(key);
30
31 lockdep_assert_held_read(&key->sem);
32
33 return epayload->decrypted_data;
34}
35
36static void nvdimm_put_key(struct key *key)
37{
38 if (!key)
39 return;
40
41 up_read(&key->sem);
42 key_put(key);
43}
44
45/*
46 * Retrieve kernel key for DIMM and request from user space if
47 * necessary. Returns a key held for read and must be put by
48 * nvdimm_put_key() before the usage goes out of scope.
49 */
50static struct key *nvdimm_request_key(struct nvdimm *nvdimm)
51{
52 struct key *key = NULL;
53 static const char NVDIMM_PREFIX[] = "nvdimm:";
54 char desc[NVDIMM_KEY_DESC_LEN + sizeof(NVDIMM_PREFIX)];
55 struct device *dev = &nvdimm->dev;
56
57 sprintf(desc, "%s%s", NVDIMM_PREFIX, nvdimm->dimm_id);
58 key = request_key(&key_type_encrypted, desc, "");
59 if (IS_ERR(key)) {
60 if (PTR_ERR(key) == -ENOKEY)
61 dev_dbg(dev, "request_key() found no key\n");
62 else
63 dev_dbg(dev, "request_key() upcall failed\n");
64 key = NULL;
65 } else {
66 struct encrypted_key_payload *epayload;
67
68 down_read(&key->sem);
69 epayload = dereference_key_locked(key);
70 if (epayload->decrypted_datalen != NVDIMM_PASSPHRASE_LEN) {
71 up_read(&key->sem);
72 key_put(key);
73 key = NULL;
74 }
75 }
76
77 return key;
78}
79
80static const void *nvdimm_get_key_payload(struct nvdimm *nvdimm,
81 struct key **key)
82{
83 *key = nvdimm_request_key(nvdimm);
84 if (!*key)
85 return zero_key;
86
87 return key_data(*key);
88}
89
90static struct key *nvdimm_lookup_user_key(struct nvdimm *nvdimm,
91 key_serial_t id, int subclass)
92{
93 key_ref_t keyref;
94 struct key *key;
95 struct encrypted_key_payload *epayload;
96 struct device *dev = &nvdimm->dev;
97
98 keyref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
99 if (IS_ERR(keyref))
100 return NULL;
101
102 key = key_ref_to_ptr(keyref);
103 if (key->type != &key_type_encrypted) {
104 key_put(key);
105 return NULL;
106 }
107
108 dev_dbg(dev, "%s: key found: %#x\n", __func__, key_serial(key));
109
110 down_read_nested(&key->sem, subclass);
111 epayload = dereference_key_locked(key);
112 if (epayload->decrypted_datalen != NVDIMM_PASSPHRASE_LEN) {
113 up_read(&key->sem);
114 key_put(key);
115 key = NULL;
116 }
117 return key;
118}
119
120static const void *nvdimm_get_user_key_payload(struct nvdimm *nvdimm,
121 key_serial_t id, int subclass, struct key **key)
122{
123 *key = NULL;
124 if (id == 0) {
125 if (subclass == NVDIMM_BASE_KEY)
126 return zero_key;
127 else
128 return NULL;
129 }
130
131 *key = nvdimm_lookup_user_key(nvdimm, id, subclass);
132 if (!*key)
133 return NULL;
134
135 return key_data(*key);
136}
137
138
139static int nvdimm_key_revalidate(struct nvdimm *nvdimm)
140{
141 struct key *key;
142 int rc;
143 const void *data;
144
145 if (!nvdimm->sec.ops->change_key)
146 return -EOPNOTSUPP;
147
148 data = nvdimm_get_key_payload(nvdimm, &key);
149
150 /*
151 * Send the same key to the hardware as new and old key to
152 * verify that the key is good.
153 */
154 rc = nvdimm->sec.ops->change_key(nvdimm, data, data, NVDIMM_USER);
155 if (rc < 0) {
156 nvdimm_put_key(key);
157 return rc;
158 }
159
160 nvdimm_put_key(key);
161 nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
162 return 0;
163}
164
165static int __nvdimm_security_unlock(struct nvdimm *nvdimm)
166{
167 struct device *dev = &nvdimm->dev;
168 struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
169 struct key *key;
170 const void *data;
171 int rc;
172
173 /* The bus lock should be held at the top level of the call stack */
174 lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
175
176 if (!nvdimm->sec.ops || !nvdimm->sec.ops->unlock
177 || !nvdimm->sec.flags)
178 return -EIO;
179
180 /* cxl_test needs this to pre-populate the security state */
181 if (IS_ENABLED(CONFIG_NVDIMM_SECURITY_TEST))
182 nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
183
184 /* No need to go further if security is disabled */
185 if (test_bit(NVDIMM_SECURITY_DISABLED, &nvdimm->sec.flags))
186 return 0;
187
188 if (test_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags)) {
189 dev_dbg(dev, "Security operation in progress.\n");
190 return -EBUSY;
191 }
192
193 /*
194 * If the pre-OS has unlocked the DIMM, attempt to send the key
195 * from request_key() to the hardware for verification. Failure
196 * to revalidate the key against the hardware results in a
197 * freeze of the security configuration. I.e. if the OS does not
198 * have the key, security is being managed pre-OS.
199 */
200 if (test_bit(NVDIMM_SECURITY_UNLOCKED, &nvdimm->sec.flags)) {
201 if (!key_revalidate)
202 return 0;
203
204 return nvdimm_key_revalidate(nvdimm);
205 } else
206 data = nvdimm_get_key_payload(nvdimm, &key);
207
208 rc = nvdimm->sec.ops->unlock(nvdimm, data);
209 dev_dbg(dev, "key: %d unlock: %s\n", key_serial(key),
210 rc == 0 ? "success" : "fail");
211 if (rc == 0)
212 set_bit(NDD_INCOHERENT, &nvdimm->flags);
213
214 nvdimm_put_key(key);
215 nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
216 return rc;
217}
218
219int nvdimm_security_unlock(struct device *dev)
220{
221 struct nvdimm *nvdimm = to_nvdimm(dev);
222
223 guard(nvdimm_bus)(dev);
224 return __nvdimm_security_unlock(nvdimm);
225}
226
227static int check_security_state(struct nvdimm *nvdimm)
228{
229 struct device *dev = &nvdimm->dev;
230
231 if (test_bit(NVDIMM_SECURITY_FROZEN, &nvdimm->sec.flags)) {
232 dev_dbg(dev, "Incorrect security state: %#lx\n",
233 nvdimm->sec.flags);
234 return -EIO;
235 }
236
237 if (test_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags)) {
238 dev_dbg(dev, "Security operation in progress.\n");
239 return -EBUSY;
240 }
241
242 return 0;
243}
244
245static int security_disable(struct nvdimm *nvdimm, unsigned int keyid,
246 enum nvdimm_passphrase_type pass_type)
247{
248 struct device *dev = &nvdimm->dev;
249 struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
250 struct key *key;
251 int rc;
252 const void *data;
253
254 /* The bus lock should be held at the top level of the call stack */
255 lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
256
257 if (!nvdimm->sec.ops || !nvdimm->sec.flags)
258 return -EOPNOTSUPP;
259
260 if (pass_type == NVDIMM_USER && !nvdimm->sec.ops->disable)
261 return -EOPNOTSUPP;
262
263 if (pass_type == NVDIMM_MASTER && !nvdimm->sec.ops->disable_master)
264 return -EOPNOTSUPP;
265
266 rc = check_security_state(nvdimm);
267 if (rc)
268 return rc;
269
270 data = nvdimm_get_user_key_payload(nvdimm, keyid,
271 NVDIMM_BASE_KEY, &key);
272 if (!data)
273 return -ENOKEY;
274
275 if (pass_type == NVDIMM_MASTER) {
276 rc = nvdimm->sec.ops->disable_master(nvdimm, data);
277 dev_dbg(dev, "key: %d disable_master: %s\n", key_serial(key),
278 rc == 0 ? "success" : "fail");
279 } else {
280 rc = nvdimm->sec.ops->disable(nvdimm, data);
281 dev_dbg(dev, "key: %d disable: %s\n", key_serial(key),
282 rc == 0 ? "success" : "fail");
283 }
284
285 nvdimm_put_key(key);
286 if (pass_type == NVDIMM_MASTER)
287 nvdimm->sec.ext_flags = nvdimm_security_flags(nvdimm, NVDIMM_MASTER);
288 else
289 nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
290 return rc;
291}
292
293static int security_update(struct nvdimm *nvdimm, unsigned int keyid,
294 unsigned int new_keyid,
295 enum nvdimm_passphrase_type pass_type)
296{
297 struct device *dev = &nvdimm->dev;
298 struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
299 struct key *key, *newkey;
300 int rc;
301 const void *data, *newdata;
302
303 /* The bus lock should be held at the top level of the call stack */
304 lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
305
306 if (!nvdimm->sec.ops || !nvdimm->sec.ops->change_key
307 || !nvdimm->sec.flags)
308 return -EOPNOTSUPP;
309
310 rc = check_security_state(nvdimm);
311 if (rc)
312 return rc;
313
314 data = nvdimm_get_user_key_payload(nvdimm, keyid,
315 NVDIMM_BASE_KEY, &key);
316 if (!data)
317 return -ENOKEY;
318
319 newdata = nvdimm_get_user_key_payload(nvdimm, new_keyid,
320 NVDIMM_NEW_KEY, &newkey);
321 if (!newdata) {
322 nvdimm_put_key(key);
323 return -ENOKEY;
324 }
325
326 rc = nvdimm->sec.ops->change_key(nvdimm, data, newdata, pass_type);
327 dev_dbg(dev, "key: %d %d update%s: %s\n",
328 key_serial(key), key_serial(newkey),
329 pass_type == NVDIMM_MASTER ? "(master)" : "(user)",
330 rc == 0 ? "success" : "fail");
331
332 nvdimm_put_key(newkey);
333 nvdimm_put_key(key);
334 if (pass_type == NVDIMM_MASTER)
335 nvdimm->sec.ext_flags = nvdimm_security_flags(nvdimm,
336 NVDIMM_MASTER);
337 else
338 nvdimm->sec.flags = nvdimm_security_flags(nvdimm,
339 NVDIMM_USER);
340 return rc;
341}
342
343static int security_erase(struct nvdimm *nvdimm, unsigned int keyid,
344 enum nvdimm_passphrase_type pass_type)
345{
346 struct device *dev = &nvdimm->dev;
347 struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
348 struct key *key = NULL;
349 int rc;
350 const void *data;
351
352 /* The bus lock should be held at the top level of the call stack */
353 lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
354
355 if (!nvdimm->sec.ops || !nvdimm->sec.ops->erase
356 || !nvdimm->sec.flags)
357 return -EOPNOTSUPP;
358
359 rc = check_security_state(nvdimm);
360 if (rc)
361 return rc;
362
363 if (!test_bit(NVDIMM_SECURITY_UNLOCKED, &nvdimm->sec.ext_flags)
364 && pass_type == NVDIMM_MASTER) {
365 dev_dbg(dev,
366 "Attempt to secure erase in wrong master state.\n");
367 return -EOPNOTSUPP;
368 }
369
370 data = nvdimm_get_user_key_payload(nvdimm, keyid,
371 NVDIMM_BASE_KEY, &key);
372 if (!data)
373 return -ENOKEY;
374
375 rc = nvdimm->sec.ops->erase(nvdimm, data, pass_type);
376 if (rc == 0)
377 set_bit(NDD_INCOHERENT, &nvdimm->flags);
378 dev_dbg(dev, "key: %d erase%s: %s\n", key_serial(key),
379 pass_type == NVDIMM_MASTER ? "(master)" : "(user)",
380 rc == 0 ? "success" : "fail");
381
382 nvdimm_put_key(key);
383 nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
384 return rc;
385}
386
387static int security_overwrite(struct nvdimm *nvdimm, unsigned int keyid)
388{
389 struct device *dev = &nvdimm->dev;
390 struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
391 struct key *key = NULL;
392 int rc;
393 const void *data;
394
395 /* The bus lock should be held at the top level of the call stack */
396 lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
397
398 if (!nvdimm->sec.ops || !nvdimm->sec.ops->overwrite
399 || !nvdimm->sec.flags)
400 return -EOPNOTSUPP;
401
402 rc = check_security_state(nvdimm);
403 if (rc)
404 return rc;
405
406 data = nvdimm_get_user_key_payload(nvdimm, keyid,
407 NVDIMM_BASE_KEY, &key);
408 if (!data)
409 return -ENOKEY;
410
411 rc = nvdimm->sec.ops->overwrite(nvdimm, data);
412 if (rc == 0)
413 set_bit(NDD_INCOHERENT, &nvdimm->flags);
414 dev_dbg(dev, "key: %d overwrite submission: %s\n", key_serial(key),
415 rc == 0 ? "success" : "fail");
416
417 nvdimm_put_key(key);
418 if (rc == 0) {
419 set_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags);
420 set_bit(NDD_WORK_PENDING, &nvdimm->flags);
421 set_bit(NVDIMM_SECURITY_OVERWRITE, &nvdimm->sec.flags);
422 /*
423 * Make sure we don't lose device while doing overwrite
424 * query.
425 */
426 get_device(dev);
427 queue_delayed_work(system_percpu_wq, &nvdimm->dwork, 0);
428 }
429
430 return rc;
431}
432
433static void __nvdimm_security_overwrite_query(struct nvdimm *nvdimm)
434{
435 struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(&nvdimm->dev);
436 int rc;
437 unsigned int tmo;
438
439 /* The bus lock should be held at the top level of the call stack */
440 lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
441
442 /*
443 * Abort and release device if we no longer have the overwrite
444 * flag set. It means the work has been canceled.
445 */
446 if (!test_bit(NDD_WORK_PENDING, &nvdimm->flags))
447 return;
448
449 tmo = nvdimm->sec.overwrite_tmo;
450
451 if (!nvdimm->sec.ops || !nvdimm->sec.ops->query_overwrite
452 || !nvdimm->sec.flags)
453 return;
454
455 rc = nvdimm->sec.ops->query_overwrite(nvdimm);
456 if (rc == -EBUSY) {
457
458 /* setup delayed work again */
459 tmo += 10;
460 queue_delayed_work(system_percpu_wq, &nvdimm->dwork, tmo * HZ);
461 nvdimm->sec.overwrite_tmo = min(15U * 60U, tmo);
462 return;
463 }
464
465 if (rc < 0)
466 dev_dbg(&nvdimm->dev, "overwrite failed\n");
467 else
468 dev_dbg(&nvdimm->dev, "overwrite completed\n");
469
470 /*
471 * Mark the overwrite work done and update dimm security flags,
472 * then send a sysfs event notification to wake up userspace
473 * poll threads to picked up the changed state.
474 */
475 nvdimm->sec.overwrite_tmo = 0;
476 clear_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags);
477 clear_bit(NDD_WORK_PENDING, &nvdimm->flags);
478 nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
479 nvdimm->sec.ext_flags = nvdimm_security_flags(nvdimm, NVDIMM_MASTER);
480 if (nvdimm->sec.overwrite_state)
481 sysfs_notify_dirent(nvdimm->sec.overwrite_state);
482 put_device(&nvdimm->dev);
483}
484
485void nvdimm_security_overwrite_query(struct work_struct *work)
486{
487 struct nvdimm *nvdimm =
488 container_of(work, typeof(*nvdimm), dwork.work);
489
490 guard(nvdimm_bus)(&nvdimm->dev);
491 __nvdimm_security_overwrite_query(nvdimm);
492}
493
494#define OPS \
495 C( OP_FREEZE, "freeze", 1), \
496 C( OP_DISABLE, "disable", 2), \
497 C( OP_DISABLE_MASTER, "disable_master", 2), \
498 C( OP_UPDATE, "update", 3), \
499 C( OP_ERASE, "erase", 2), \
500 C( OP_OVERWRITE, "overwrite", 2), \
501 C( OP_MASTER_UPDATE, "master_update", 3), \
502 C( OP_MASTER_ERASE, "master_erase", 2)
503#undef C
504#define C(a, b, c) a
505enum nvdimmsec_op_ids { OPS };
506#undef C
507#define C(a, b, c) { b, c }
508static struct {
509 const char *name;
510 int args;
511} ops[] = { OPS };
512#undef C
513
514#define SEC_CMD_SIZE 32
515#define KEY_ID_SIZE 10
516
517ssize_t nvdimm_security_store(struct device *dev, const char *buf, size_t len)
518{
519 struct nvdimm *nvdimm = to_nvdimm(dev);
520 ssize_t rc;
521 char cmd[SEC_CMD_SIZE+1], keystr[KEY_ID_SIZE+1],
522 nkeystr[KEY_ID_SIZE+1];
523 unsigned int key, newkey;
524 int i;
525
526 rc = sscanf(buf, "%"__stringify(SEC_CMD_SIZE)"s"
527 " %"__stringify(KEY_ID_SIZE)"s"
528 " %"__stringify(KEY_ID_SIZE)"s",
529 cmd, keystr, nkeystr);
530 if (rc < 1)
531 return -EINVAL;
532 for (i = 0; i < ARRAY_SIZE(ops); i++)
533 if (sysfs_streq(cmd, ops[i].name))
534 break;
535 if (i >= ARRAY_SIZE(ops))
536 return -EINVAL;
537 if (ops[i].args > 1)
538 rc = kstrtouint(keystr, 0, &key);
539 if (rc >= 0 && ops[i].args > 2)
540 rc = kstrtouint(nkeystr, 0, &newkey);
541 if (rc < 0)
542 return rc;
543
544 if (i == OP_FREEZE) {
545 dev_dbg(dev, "freeze\n");
546 rc = nvdimm_security_freeze(nvdimm);
547 } else if (i == OP_DISABLE) {
548 dev_dbg(dev, "disable %u\n", key);
549 rc = security_disable(nvdimm, key, NVDIMM_USER);
550 } else if (i == OP_DISABLE_MASTER) {
551 dev_dbg(dev, "disable_master %u\n", key);
552 rc = security_disable(nvdimm, key, NVDIMM_MASTER);
553 } else if (i == OP_UPDATE || i == OP_MASTER_UPDATE) {
554 dev_dbg(dev, "%s %u %u\n", ops[i].name, key, newkey);
555 rc = security_update(nvdimm, key, newkey, i == OP_UPDATE
556 ? NVDIMM_USER : NVDIMM_MASTER);
557 } else if (i == OP_ERASE || i == OP_MASTER_ERASE) {
558 dev_dbg(dev, "%s %u\n", ops[i].name, key);
559 if (atomic_read(&nvdimm->busy)) {
560 dev_dbg(dev, "Unable to secure erase while DIMM active.\n");
561 return -EBUSY;
562 }
563 rc = security_erase(nvdimm, key, i == OP_ERASE
564 ? NVDIMM_USER : NVDIMM_MASTER);
565 } else if (i == OP_OVERWRITE) {
566 dev_dbg(dev, "overwrite %u\n", key);
567 if (atomic_read(&nvdimm->busy)) {
568 dev_dbg(dev, "Unable to overwrite while DIMM active.\n");
569 return -EBUSY;
570 }
571 rc = security_overwrite(nvdimm, key);
572 } else
573 return -EINVAL;
574
575 if (rc == 0)
576 rc = len;
577 return rc;
578}