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
21 static bool key_revalidate = true;
22 module_param(key_revalidate, bool, 0444);
23 MODULE_PARM_DESC(key_revalidate, "Require key validation at init.");
24
25 static const char zero_key[NVDIMM_PASSPHRASE_LEN];
26
key_data(struct key * key)27 static 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
nvdimm_put_key(struct key * key)36 static 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 */
nvdimm_request_key(struct nvdimm * nvdimm)50 static 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
nvdimm_get_key_payload(struct nvdimm * nvdimm,struct key ** key)80 static 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
nvdimm_lookup_user_key(struct nvdimm * nvdimm,key_serial_t id,int subclass)90 static 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
nvdimm_get_user_key_payload(struct nvdimm * nvdimm,key_serial_t id,int subclass,struct key ** key)120 static 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
nvdimm_key_revalidate(struct nvdimm * nvdimm)139 static 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
__nvdimm_security_unlock(struct nvdimm * nvdimm)165 static 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
nvdimm_security_unlock(struct device * dev)219 int nvdimm_security_unlock(struct device *dev)
220 {
221 struct nvdimm *nvdimm = to_nvdimm(dev);
222 int rc;
223
224 nvdimm_bus_lock(dev);
225 rc = __nvdimm_security_unlock(nvdimm);
226 nvdimm_bus_unlock(dev);
227 return rc;
228 }
229
check_security_state(struct nvdimm * nvdimm)230 static int check_security_state(struct nvdimm *nvdimm)
231 {
232 struct device *dev = &nvdimm->dev;
233
234 if (test_bit(NVDIMM_SECURITY_FROZEN, &nvdimm->sec.flags)) {
235 dev_dbg(dev, "Incorrect security state: %#lx\n",
236 nvdimm->sec.flags);
237 return -EIO;
238 }
239
240 if (test_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags)) {
241 dev_dbg(dev, "Security operation in progress.\n");
242 return -EBUSY;
243 }
244
245 return 0;
246 }
247
security_disable(struct nvdimm * nvdimm,unsigned int keyid,enum nvdimm_passphrase_type pass_type)248 static int security_disable(struct nvdimm *nvdimm, unsigned int keyid,
249 enum nvdimm_passphrase_type pass_type)
250 {
251 struct device *dev = &nvdimm->dev;
252 struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
253 struct key *key;
254 int rc;
255 const void *data;
256
257 /* The bus lock should be held at the top level of the call stack */
258 lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
259
260 if (!nvdimm->sec.ops || !nvdimm->sec.flags)
261 return -EOPNOTSUPP;
262
263 if (pass_type == NVDIMM_USER && !nvdimm->sec.ops->disable)
264 return -EOPNOTSUPP;
265
266 if (pass_type == NVDIMM_MASTER && !nvdimm->sec.ops->disable_master)
267 return -EOPNOTSUPP;
268
269 rc = check_security_state(nvdimm);
270 if (rc)
271 return rc;
272
273 data = nvdimm_get_user_key_payload(nvdimm, keyid,
274 NVDIMM_BASE_KEY, &key);
275 if (!data)
276 return -ENOKEY;
277
278 if (pass_type == NVDIMM_MASTER) {
279 rc = nvdimm->sec.ops->disable_master(nvdimm, data);
280 dev_dbg(dev, "key: %d disable_master: %s\n", key_serial(key),
281 rc == 0 ? "success" : "fail");
282 } else {
283 rc = nvdimm->sec.ops->disable(nvdimm, data);
284 dev_dbg(dev, "key: %d disable: %s\n", key_serial(key),
285 rc == 0 ? "success" : "fail");
286 }
287
288 nvdimm_put_key(key);
289 if (pass_type == NVDIMM_MASTER)
290 nvdimm->sec.ext_flags = nvdimm_security_flags(nvdimm, NVDIMM_MASTER);
291 else
292 nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
293 return rc;
294 }
295
security_update(struct nvdimm * nvdimm,unsigned int keyid,unsigned int new_keyid,enum nvdimm_passphrase_type pass_type)296 static int security_update(struct nvdimm *nvdimm, unsigned int keyid,
297 unsigned int new_keyid,
298 enum nvdimm_passphrase_type pass_type)
299 {
300 struct device *dev = &nvdimm->dev;
301 struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
302 struct key *key, *newkey;
303 int rc;
304 const void *data, *newdata;
305
306 /* The bus lock should be held at the top level of the call stack */
307 lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
308
309 if (!nvdimm->sec.ops || !nvdimm->sec.ops->change_key
310 || !nvdimm->sec.flags)
311 return -EOPNOTSUPP;
312
313 rc = check_security_state(nvdimm);
314 if (rc)
315 return rc;
316
317 data = nvdimm_get_user_key_payload(nvdimm, keyid,
318 NVDIMM_BASE_KEY, &key);
319 if (!data)
320 return -ENOKEY;
321
322 newdata = nvdimm_get_user_key_payload(nvdimm, new_keyid,
323 NVDIMM_NEW_KEY, &newkey);
324 if (!newdata) {
325 nvdimm_put_key(key);
326 return -ENOKEY;
327 }
328
329 rc = nvdimm->sec.ops->change_key(nvdimm, data, newdata, pass_type);
330 dev_dbg(dev, "key: %d %d update%s: %s\n",
331 key_serial(key), key_serial(newkey),
332 pass_type == NVDIMM_MASTER ? "(master)" : "(user)",
333 rc == 0 ? "success" : "fail");
334
335 nvdimm_put_key(newkey);
336 nvdimm_put_key(key);
337 if (pass_type == NVDIMM_MASTER)
338 nvdimm->sec.ext_flags = nvdimm_security_flags(nvdimm,
339 NVDIMM_MASTER);
340 else
341 nvdimm->sec.flags = nvdimm_security_flags(nvdimm,
342 NVDIMM_USER);
343 return rc;
344 }
345
security_erase(struct nvdimm * nvdimm,unsigned int keyid,enum nvdimm_passphrase_type pass_type)346 static int security_erase(struct nvdimm *nvdimm, unsigned int keyid,
347 enum nvdimm_passphrase_type pass_type)
348 {
349 struct device *dev = &nvdimm->dev;
350 struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
351 struct key *key = NULL;
352 int rc;
353 const void *data;
354
355 /* The bus lock should be held at the top level of the call stack */
356 lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
357
358 if (!nvdimm->sec.ops || !nvdimm->sec.ops->erase
359 || !nvdimm->sec.flags)
360 return -EOPNOTSUPP;
361
362 rc = check_security_state(nvdimm);
363 if (rc)
364 return rc;
365
366 if (!test_bit(NVDIMM_SECURITY_UNLOCKED, &nvdimm->sec.ext_flags)
367 && pass_type == NVDIMM_MASTER) {
368 dev_dbg(dev,
369 "Attempt to secure erase in wrong master state.\n");
370 return -EOPNOTSUPP;
371 }
372
373 data = nvdimm_get_user_key_payload(nvdimm, keyid,
374 NVDIMM_BASE_KEY, &key);
375 if (!data)
376 return -ENOKEY;
377
378 rc = nvdimm->sec.ops->erase(nvdimm, data, pass_type);
379 if (rc == 0)
380 set_bit(NDD_INCOHERENT, &nvdimm->flags);
381 dev_dbg(dev, "key: %d erase%s: %s\n", key_serial(key),
382 pass_type == NVDIMM_MASTER ? "(master)" : "(user)",
383 rc == 0 ? "success" : "fail");
384
385 nvdimm_put_key(key);
386 nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
387 return rc;
388 }
389
security_overwrite(struct nvdimm * nvdimm,unsigned int keyid)390 static int security_overwrite(struct nvdimm *nvdimm, unsigned int keyid)
391 {
392 struct device *dev = &nvdimm->dev;
393 struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
394 struct key *key = NULL;
395 int rc;
396 const void *data;
397
398 /* The bus lock should be held at the top level of the call stack */
399 lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
400
401 if (!nvdimm->sec.ops || !nvdimm->sec.ops->overwrite
402 || !nvdimm->sec.flags)
403 return -EOPNOTSUPP;
404
405 rc = check_security_state(nvdimm);
406 if (rc)
407 return rc;
408
409 data = nvdimm_get_user_key_payload(nvdimm, keyid,
410 NVDIMM_BASE_KEY, &key);
411 if (!data)
412 return -ENOKEY;
413
414 rc = nvdimm->sec.ops->overwrite(nvdimm, data);
415 if (rc == 0)
416 set_bit(NDD_INCOHERENT, &nvdimm->flags);
417 dev_dbg(dev, "key: %d overwrite submission: %s\n", key_serial(key),
418 rc == 0 ? "success" : "fail");
419
420 nvdimm_put_key(key);
421 if (rc == 0) {
422 set_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags);
423 set_bit(NDD_WORK_PENDING, &nvdimm->flags);
424 set_bit(NVDIMM_SECURITY_OVERWRITE, &nvdimm->sec.flags);
425 /*
426 * Make sure we don't lose device while doing overwrite
427 * query.
428 */
429 get_device(dev);
430 queue_delayed_work(system_wq, &nvdimm->dwork, 0);
431 }
432
433 return rc;
434 }
435
__nvdimm_security_overwrite_query(struct nvdimm * nvdimm)436 static void __nvdimm_security_overwrite_query(struct nvdimm *nvdimm)
437 {
438 struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(&nvdimm->dev);
439 int rc;
440 unsigned int tmo;
441
442 /* The bus lock should be held at the top level of the call stack */
443 lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
444
445 /*
446 * Abort and release device if we no longer have the overwrite
447 * flag set. It means the work has been canceled.
448 */
449 if (!test_bit(NDD_WORK_PENDING, &nvdimm->flags))
450 return;
451
452 tmo = nvdimm->sec.overwrite_tmo;
453
454 if (!nvdimm->sec.ops || !nvdimm->sec.ops->query_overwrite
455 || !nvdimm->sec.flags)
456 return;
457
458 rc = nvdimm->sec.ops->query_overwrite(nvdimm);
459 if (rc == -EBUSY) {
460
461 /* setup delayed work again */
462 tmo += 10;
463 queue_delayed_work(system_wq, &nvdimm->dwork, tmo * HZ);
464 nvdimm->sec.overwrite_tmo = min(15U * 60U, tmo);
465 return;
466 }
467
468 if (rc < 0)
469 dev_dbg(&nvdimm->dev, "overwrite failed\n");
470 else
471 dev_dbg(&nvdimm->dev, "overwrite completed\n");
472
473 /*
474 * Mark the overwrite work done and update dimm security flags,
475 * then send a sysfs event notification to wake up userspace
476 * poll threads to picked up the changed state.
477 */
478 nvdimm->sec.overwrite_tmo = 0;
479 clear_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags);
480 clear_bit(NDD_WORK_PENDING, &nvdimm->flags);
481 nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
482 nvdimm->sec.ext_flags = nvdimm_security_flags(nvdimm, NVDIMM_MASTER);
483 if (nvdimm->sec.overwrite_state)
484 sysfs_notify_dirent(nvdimm->sec.overwrite_state);
485 put_device(&nvdimm->dev);
486 }
487
nvdimm_security_overwrite_query(struct work_struct * work)488 void nvdimm_security_overwrite_query(struct work_struct *work)
489 {
490 struct nvdimm *nvdimm =
491 container_of(work, typeof(*nvdimm), dwork.work);
492
493 nvdimm_bus_lock(&nvdimm->dev);
494 __nvdimm_security_overwrite_query(nvdimm);
495 nvdimm_bus_unlock(&nvdimm->dev);
496 }
497
498 #define OPS \
499 C( OP_FREEZE, "freeze", 1), \
500 C( OP_DISABLE, "disable", 2), \
501 C( OP_DISABLE_MASTER, "disable_master", 2), \
502 C( OP_UPDATE, "update", 3), \
503 C( OP_ERASE, "erase", 2), \
504 C( OP_OVERWRITE, "overwrite", 2), \
505 C( OP_MASTER_UPDATE, "master_update", 3), \
506 C( OP_MASTER_ERASE, "master_erase", 2)
507 #undef C
508 #define C(a, b, c) a
509 enum nvdimmsec_op_ids { OPS };
510 #undef C
511 #define C(a, b, c) { b, c }
512 static struct {
513 const char *name;
514 int args;
515 } ops[] = { OPS };
516 #undef C
517
518 #define SEC_CMD_SIZE 32
519 #define KEY_ID_SIZE 10
520
nvdimm_security_store(struct device * dev,const char * buf,size_t len)521 ssize_t nvdimm_security_store(struct device *dev, const char *buf, size_t len)
522 {
523 struct nvdimm *nvdimm = to_nvdimm(dev);
524 ssize_t rc;
525 char cmd[SEC_CMD_SIZE+1], keystr[KEY_ID_SIZE+1],
526 nkeystr[KEY_ID_SIZE+1];
527 unsigned int key, newkey;
528 int i;
529
530 rc = sscanf(buf, "%"__stringify(SEC_CMD_SIZE)"s"
531 " %"__stringify(KEY_ID_SIZE)"s"
532 " %"__stringify(KEY_ID_SIZE)"s",
533 cmd, keystr, nkeystr);
534 if (rc < 1)
535 return -EINVAL;
536 for (i = 0; i < ARRAY_SIZE(ops); i++)
537 if (sysfs_streq(cmd, ops[i].name))
538 break;
539 if (i >= ARRAY_SIZE(ops))
540 return -EINVAL;
541 if (ops[i].args > 1)
542 rc = kstrtouint(keystr, 0, &key);
543 if (rc >= 0 && ops[i].args > 2)
544 rc = kstrtouint(nkeystr, 0, &newkey);
545 if (rc < 0)
546 return rc;
547
548 if (i == OP_FREEZE) {
549 dev_dbg(dev, "freeze\n");
550 rc = nvdimm_security_freeze(nvdimm);
551 } else if (i == OP_DISABLE) {
552 dev_dbg(dev, "disable %u\n", key);
553 rc = security_disable(nvdimm, key, NVDIMM_USER);
554 } else if (i == OP_DISABLE_MASTER) {
555 dev_dbg(dev, "disable_master %u\n", key);
556 rc = security_disable(nvdimm, key, NVDIMM_MASTER);
557 } else if (i == OP_UPDATE || i == OP_MASTER_UPDATE) {
558 dev_dbg(dev, "%s %u %u\n", ops[i].name, key, newkey);
559 rc = security_update(nvdimm, key, newkey, i == OP_UPDATE
560 ? NVDIMM_USER : NVDIMM_MASTER);
561 } else if (i == OP_ERASE || i == OP_MASTER_ERASE) {
562 dev_dbg(dev, "%s %u\n", ops[i].name, key);
563 if (atomic_read(&nvdimm->busy)) {
564 dev_dbg(dev, "Unable to secure erase while DIMM active.\n");
565 return -EBUSY;
566 }
567 rc = security_erase(nvdimm, key, i == OP_ERASE
568 ? NVDIMM_USER : NVDIMM_MASTER);
569 } else if (i == OP_OVERWRITE) {
570 dev_dbg(dev, "overwrite %u\n", key);
571 if (atomic_read(&nvdimm->busy)) {
572 dev_dbg(dev, "Unable to overwrite while DIMM active.\n");
573 return -EBUSY;
574 }
575 rc = security_overwrite(nvdimm, key);
576 } else
577 return -EINVAL;
578
579 if (rc == 0)
580 rc = len;
581 return rc;
582 }
583