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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2019 Google LLC
4 */
5
6/**
7 * DOC: blk-crypto profiles
8 *
9 * 'struct blk_crypto_profile' contains all generic inline encryption-related
10 * state for a particular inline encryption device. blk_crypto_profile serves
11 * as the way that drivers for inline encryption hardware expose their crypto
12 * capabilities and certain functions (e.g., functions to program and evict
13 * keys) to upper layers. Device drivers that want to support inline encryption
14 * construct a crypto profile, then associate it with the disk's request_queue.
15 *
16 * If the device has keyslots, then its blk_crypto_profile also handles managing
17 * these keyslots in a device-independent way, using the driver-provided
18 * functions to program and evict keys as needed. This includes keeping track
19 * of which key and how many I/O requests are using each keyslot, getting
20 * keyslots for I/O requests, and handling key eviction requests.
21 *
22 * For more information, see Documentation/block/inline-encryption.rst.
23 */
24
25#define pr_fmt(fmt) "blk-crypto: " fmt
26
27#include <linux/blk-crypto-profile.h>
28#include <linux/device.h>
29#include <linux/atomic.h>
30#include <linux/mutex.h>
31#include <linux/pm_runtime.h>
32#include <linux/wait.h>
33#include <linux/blkdev.h>
34#include <linux/blk-integrity.h>
35#include "blk-crypto-internal.h"
36
37struct blk_crypto_keyslot {
38 atomic_t slot_refs;
39 struct list_head idle_slot_node;
40 struct hlist_node hash_node;
41 const struct blk_crypto_key *key;
42 struct blk_crypto_profile *profile;
43};
44
45static inline void blk_crypto_hw_enter(struct blk_crypto_profile *profile)
46{
47 /*
48 * Calling into the driver requires profile->lock held and the device
49 * resumed. But we must resume the device first, since that can acquire
50 * and release profile->lock via blk_crypto_reprogram_all_keys().
51 */
52 if (profile->dev)
53 pm_runtime_get_sync(profile->dev);
54 down_write(&profile->lock);
55}
56
57static inline void blk_crypto_hw_exit(struct blk_crypto_profile *profile)
58{
59 up_write(&profile->lock);
60 if (profile->dev)
61 pm_runtime_put_sync(profile->dev);
62}
63
64/**
65 * blk_crypto_profile_init() - Initialize a blk_crypto_profile
66 * @profile: the blk_crypto_profile to initialize
67 * @num_slots: the number of keyslots
68 *
69 * Storage drivers must call this when starting to set up a blk_crypto_profile,
70 * before filling in additional fields.
71 *
72 * Return: 0 on success, or else a negative error code.
73 */
74int blk_crypto_profile_init(struct blk_crypto_profile *profile,
75 unsigned int num_slots)
76{
77 unsigned int slot;
78 unsigned int i;
79 unsigned int slot_hashtable_size;
80
81 memset(profile, 0, sizeof(*profile));
82 init_rwsem(&profile->lock);
83
84 if (num_slots == 0)
85 return 0;
86
87 /* Initialize keyslot management data. */
88
89 profile->slots = kvcalloc(num_slots, sizeof(profile->slots[0]),
90 GFP_KERNEL);
91 if (!profile->slots)
92 return -ENOMEM;
93
94 profile->num_slots = num_slots;
95
96 init_waitqueue_head(&profile->idle_slots_wait_queue);
97 INIT_LIST_HEAD(&profile->idle_slots);
98
99 for (slot = 0; slot < num_slots; slot++) {
100 profile->slots[slot].profile = profile;
101 list_add_tail(&profile->slots[slot].idle_slot_node,
102 &profile->idle_slots);
103 }
104
105 spin_lock_init(&profile->idle_slots_lock);
106
107 slot_hashtable_size = roundup_pow_of_two(num_slots);
108 /*
109 * hash_ptr() assumes bits != 0, so ensure the hash table has at least 2
110 * buckets. This only makes a difference when there is only 1 keyslot.
111 */
112 if (slot_hashtable_size < 2)
113 slot_hashtable_size = 2;
114
115 profile->log_slot_ht_size = ilog2(slot_hashtable_size);
116 profile->slot_hashtable =
117 kvmalloc_array(slot_hashtable_size,
118 sizeof(profile->slot_hashtable[0]), GFP_KERNEL);
119 if (!profile->slot_hashtable)
120 goto err_destroy;
121 for (i = 0; i < slot_hashtable_size; i++)
122 INIT_HLIST_HEAD(&profile->slot_hashtable[i]);
123
124 return 0;
125
126err_destroy:
127 blk_crypto_profile_destroy(profile);
128 return -ENOMEM;
129}
130EXPORT_SYMBOL_GPL(blk_crypto_profile_init);
131
132static void blk_crypto_profile_destroy_callback(void *profile)
133{
134 blk_crypto_profile_destroy(profile);
135}
136
137/**
138 * devm_blk_crypto_profile_init() - Resource-managed blk_crypto_profile_init()
139 * @dev: the device which owns the blk_crypto_profile
140 * @profile: the blk_crypto_profile to initialize
141 * @num_slots: the number of keyslots
142 *
143 * Like blk_crypto_profile_init(), but causes blk_crypto_profile_destroy() to be
144 * called automatically on driver detach.
145 *
146 * Return: 0 on success, or else a negative error code.
147 */
148int devm_blk_crypto_profile_init(struct device *dev,
149 struct blk_crypto_profile *profile,
150 unsigned int num_slots)
151{
152 int err = blk_crypto_profile_init(profile, num_slots);
153
154 if (err)
155 return err;
156
157 return devm_add_action_or_reset(dev,
158 blk_crypto_profile_destroy_callback,
159 profile);
160}
161EXPORT_SYMBOL_GPL(devm_blk_crypto_profile_init);
162
163static inline struct hlist_head *
164blk_crypto_hash_bucket_for_key(struct blk_crypto_profile *profile,
165 const struct blk_crypto_key *key)
166{
167 return &profile->slot_hashtable[
168 hash_ptr(key, profile->log_slot_ht_size)];
169}
170
171static void
172blk_crypto_remove_slot_from_lru_list(struct blk_crypto_keyslot *slot)
173{
174 struct blk_crypto_profile *profile = slot->profile;
175 unsigned long flags;
176
177 spin_lock_irqsave(&profile->idle_slots_lock, flags);
178 list_del(&slot->idle_slot_node);
179 spin_unlock_irqrestore(&profile->idle_slots_lock, flags);
180}
181
182static struct blk_crypto_keyslot *
183blk_crypto_find_keyslot(struct blk_crypto_profile *profile,
184 const struct blk_crypto_key *key)
185{
186 const struct hlist_head *head =
187 blk_crypto_hash_bucket_for_key(profile, key);
188 struct blk_crypto_keyslot *slotp;
189
190 hlist_for_each_entry(slotp, head, hash_node) {
191 if (slotp->key == key)
192 return slotp;
193 }
194 return NULL;
195}
196
197static struct blk_crypto_keyslot *
198blk_crypto_find_and_grab_keyslot(struct blk_crypto_profile *profile,
199 const struct blk_crypto_key *key)
200{
201 struct blk_crypto_keyslot *slot;
202
203 slot = blk_crypto_find_keyslot(profile, key);
204 if (!slot)
205 return NULL;
206 if (atomic_inc_return(&slot->slot_refs) == 1) {
207 /* Took first reference to this slot; remove it from LRU list */
208 blk_crypto_remove_slot_from_lru_list(slot);
209 }
210 return slot;
211}
212
213/**
214 * blk_crypto_keyslot_index() - Get the index of a keyslot
215 * @slot: a keyslot that blk_crypto_get_keyslot() returned
216 *
217 * Return: the 0-based index of the keyslot within the device's keyslots.
218 */
219unsigned int blk_crypto_keyslot_index(struct blk_crypto_keyslot *slot)
220{
221 return slot - slot->profile->slots;
222}
223EXPORT_SYMBOL_GPL(blk_crypto_keyslot_index);
224
225/**
226 * blk_crypto_get_keyslot() - Get a keyslot for a key, if needed.
227 * @profile: the crypto profile of the device the key will be used on
228 * @key: the key that will be used
229 * @slot_ptr: If a keyslot is allocated, an opaque pointer to the keyslot struct
230 * will be stored here; otherwise NULL will be stored here.
231 *
232 * If the device has keyslots, this gets a keyslot that's been programmed with
233 * the specified key. If the key is already in a slot, this reuses it;
234 * otherwise this waits for a slot to become idle and programs the key into it.
235 *
236 * This must be paired with a call to blk_crypto_put_keyslot().
237 *
238 * Context: Process context. Takes and releases profile->lock.
239 * Return: BLK_STS_OK on success, meaning that either a keyslot was allocated or
240 * one wasn't needed; or a blk_status_t error on failure.
241 */
242blk_status_t blk_crypto_get_keyslot(struct blk_crypto_profile *profile,
243 const struct blk_crypto_key *key,
244 struct blk_crypto_keyslot **slot_ptr)
245{
246 struct blk_crypto_keyslot *slot;
247 int slot_idx;
248 int err;
249
250 *slot_ptr = NULL;
251
252 /*
253 * If the device has no concept of "keyslots", then there is no need to
254 * get one.
255 */
256 if (profile->num_slots == 0)
257 return BLK_STS_OK;
258
259 down_read(&profile->lock);
260 slot = blk_crypto_find_and_grab_keyslot(profile, key);
261 up_read(&profile->lock);
262 if (slot)
263 goto success;
264
265 for (;;) {
266 blk_crypto_hw_enter(profile);
267 slot = blk_crypto_find_and_grab_keyslot(profile, key);
268 if (slot) {
269 blk_crypto_hw_exit(profile);
270 goto success;
271 }
272
273 /*
274 * If we're here, that means there wasn't a slot that was
275 * already programmed with the key. So try to program it.
276 */
277 if (!list_empty(&profile->idle_slots))
278 break;
279
280 blk_crypto_hw_exit(profile);
281 wait_event(profile->idle_slots_wait_queue,
282 !list_empty(&profile->idle_slots));
283 }
284
285 slot = list_first_entry(&profile->idle_slots, struct blk_crypto_keyslot,
286 idle_slot_node);
287 slot_idx = blk_crypto_keyslot_index(slot);
288
289 err = profile->ll_ops.keyslot_program(profile, key, slot_idx);
290 if (err) {
291 wake_up(&profile->idle_slots_wait_queue);
292 blk_crypto_hw_exit(profile);
293 return errno_to_blk_status(err);
294 }
295
296 /* Move this slot to the hash list for the new key. */
297 if (slot->key)
298 hlist_del(&slot->hash_node);
299 slot->key = key;
300 hlist_add_head(&slot->hash_node,
301 blk_crypto_hash_bucket_for_key(profile, key));
302
303 atomic_set(&slot->slot_refs, 1);
304
305 blk_crypto_remove_slot_from_lru_list(slot);
306
307 blk_crypto_hw_exit(profile);
308success:
309 *slot_ptr = slot;
310 return BLK_STS_OK;
311}
312
313/**
314 * blk_crypto_put_keyslot() - Release a reference to a keyslot
315 * @slot: The keyslot to release the reference of (may be NULL).
316 *
317 * Context: Any context.
318 */
319void blk_crypto_put_keyslot(struct blk_crypto_keyslot *slot)
320{
321 struct blk_crypto_profile *profile;
322 unsigned long flags;
323
324 if (!slot)
325 return;
326
327 profile = slot->profile;
328
329 if (atomic_dec_and_lock_irqsave(&slot->slot_refs,
330 &profile->idle_slots_lock, flags)) {
331 list_add_tail(&slot->idle_slot_node, &profile->idle_slots);
332 spin_unlock_irqrestore(&profile->idle_slots_lock, flags);
333 wake_up(&profile->idle_slots_wait_queue);
334 }
335}
336
337/**
338 * __blk_crypto_cfg_supported() - Check whether the given crypto profile
339 * supports the given crypto configuration.
340 * @profile: the crypto profile to check
341 * @cfg: the crypto configuration to check for
342 *
343 * Return: %true if @profile supports the given @cfg.
344 */
345bool __blk_crypto_cfg_supported(struct blk_crypto_profile *profile,
346 const struct blk_crypto_config *cfg)
347{
348 if (!profile)
349 return false;
350 if (!(profile->modes_supported[cfg->crypto_mode] & cfg->data_unit_size))
351 return false;
352 if (profile->max_dun_bytes_supported < cfg->dun_bytes)
353 return false;
354 return true;
355}
356
357/**
358 * __blk_crypto_evict_key() - Evict a key from a device.
359 * @profile: the crypto profile of the device
360 * @key: the key to evict. It must not still be used in any I/O.
361 *
362 * If the device has keyslots, this finds the keyslot (if any) that contains the
363 * specified key and calls the driver's keyslot_evict function to evict it.
364 *
365 * Otherwise, this just calls the driver's keyslot_evict function if it is
366 * implemented, passing just the key (without any particular keyslot). This
367 * allows layered devices to evict the key from their underlying devices.
368 *
369 * Context: Process context. Takes and releases profile->lock.
370 * Return: 0 on success or if there's no keyslot with the specified key, -EBUSY
371 * if the keyslot is still in use, or another -errno value on other
372 * error.
373 */
374int __blk_crypto_evict_key(struct blk_crypto_profile *profile,
375 const struct blk_crypto_key *key)
376{
377 struct blk_crypto_keyslot *slot;
378 int err = 0;
379
380 if (profile->num_slots == 0) {
381 if (profile->ll_ops.keyslot_evict) {
382 blk_crypto_hw_enter(profile);
383 err = profile->ll_ops.keyslot_evict(profile, key, -1);
384 blk_crypto_hw_exit(profile);
385 return err;
386 }
387 return 0;
388 }
389
390 blk_crypto_hw_enter(profile);
391 slot = blk_crypto_find_keyslot(profile, key);
392 if (!slot)
393 goto out_unlock;
394
395 if (WARN_ON_ONCE(atomic_read(&slot->slot_refs) != 0)) {
396 err = -EBUSY;
397 goto out_unlock;
398 }
399 err = profile->ll_ops.keyslot_evict(profile, key,
400 blk_crypto_keyslot_index(slot));
401 if (err)
402 goto out_unlock;
403
404 hlist_del(&slot->hash_node);
405 slot->key = NULL;
406 err = 0;
407out_unlock:
408 blk_crypto_hw_exit(profile);
409 return err;
410}
411
412/**
413 * blk_crypto_reprogram_all_keys() - Re-program all keyslots.
414 * @profile: The crypto profile
415 *
416 * Re-program all keyslots that are supposed to have a key programmed. This is
417 * intended only for use by drivers for hardware that loses its keys on reset.
418 *
419 * Context: Process context. Takes and releases profile->lock.
420 */
421void blk_crypto_reprogram_all_keys(struct blk_crypto_profile *profile)
422{
423 unsigned int slot;
424
425 if (profile->num_slots == 0)
426 return;
427
428 /* This is for device initialization, so don't resume the device */
429 down_write(&profile->lock);
430 for (slot = 0; slot < profile->num_slots; slot++) {
431 const struct blk_crypto_key *key = profile->slots[slot].key;
432 int err;
433
434 if (!key)
435 continue;
436
437 err = profile->ll_ops.keyslot_program(profile, key, slot);
438 WARN_ON(err);
439 }
440 up_write(&profile->lock);
441}
442EXPORT_SYMBOL_GPL(blk_crypto_reprogram_all_keys);
443
444void blk_crypto_profile_destroy(struct blk_crypto_profile *profile)
445{
446 if (!profile)
447 return;
448 kvfree(profile->slot_hashtable);
449 kvfree_sensitive(profile->slots,
450 sizeof(profile->slots[0]) * profile->num_slots);
451 memzero_explicit(profile, sizeof(*profile));
452}
453EXPORT_SYMBOL_GPL(blk_crypto_profile_destroy);
454
455bool blk_crypto_register(struct blk_crypto_profile *profile,
456 struct request_queue *q)
457{
458 if (blk_integrity_queue_supports_integrity(q)) {
459 pr_warn("Integrity and hardware inline encryption are not supported together. Disabling hardware inline encryption.\n");
460 return false;
461 }
462 q->crypto_profile = profile;
463 return true;
464}
465EXPORT_SYMBOL_GPL(blk_crypto_register);
466
467/**
468 * blk_crypto_intersect_capabilities() - restrict supported crypto capabilities
469 * by child device
470 * @parent: the crypto profile for the parent device
471 * @child: the crypto profile for the child device, or NULL
472 *
473 * This clears all crypto capabilities in @parent that aren't set in @child. If
474 * @child is NULL, then this clears all parent capabilities.
475 *
476 * Only use this when setting up the crypto profile for a layered device, before
477 * it's been exposed yet.
478 */
479void blk_crypto_intersect_capabilities(struct blk_crypto_profile *parent,
480 const struct blk_crypto_profile *child)
481{
482 if (child) {
483 unsigned int i;
484
485 parent->max_dun_bytes_supported =
486 min(parent->max_dun_bytes_supported,
487 child->max_dun_bytes_supported);
488 for (i = 0; i < ARRAY_SIZE(child->modes_supported); i++)
489 parent->modes_supported[i] &= child->modes_supported[i];
490 } else {
491 parent->max_dun_bytes_supported = 0;
492 memset(parent->modes_supported, 0,
493 sizeof(parent->modes_supported));
494 }
495}
496EXPORT_SYMBOL_GPL(blk_crypto_intersect_capabilities);
497
498/**
499 * blk_crypto_has_capabilities() - Check whether @target supports at least all
500 * the crypto capabilities that @reference does.
501 * @target: the target profile
502 * @reference: the reference profile
503 *
504 * Return: %true if @target supports all the crypto capabilities of @reference.
505 */
506bool blk_crypto_has_capabilities(const struct blk_crypto_profile *target,
507 const struct blk_crypto_profile *reference)
508{
509 int i;
510
511 if (!reference)
512 return true;
513
514 if (!target)
515 return false;
516
517 for (i = 0; i < ARRAY_SIZE(target->modes_supported); i++) {
518 if (reference->modes_supported[i] & ~target->modes_supported[i])
519 return false;
520 }
521
522 if (reference->max_dun_bytes_supported >
523 target->max_dun_bytes_supported)
524 return false;
525
526 return true;
527}
528EXPORT_SYMBOL_GPL(blk_crypto_has_capabilities);
529
530/**
531 * blk_crypto_update_capabilities() - Update the capabilities of a crypto
532 * profile to match those of another crypto
533 * profile.
534 * @dst: The crypto profile whose capabilities to update.
535 * @src: The crypto profile whose capabilities this function will update @dst's
536 * capabilities to.
537 *
538 * Blk-crypto requires that crypto capabilities that were
539 * advertised when a bio was created continue to be supported by the
540 * device until that bio is ended. This is turn means that a device cannot
541 * shrink its advertised crypto capabilities without any explicit
542 * synchronization with upper layers. So if there's no such explicit
543 * synchronization, @src must support all the crypto capabilities that
544 * @dst does (i.e. we need blk_crypto_has_capabilities(@src, @dst)).
545 *
546 * Note also that as long as the crypto capabilities are being expanded, the
547 * order of updates becoming visible is not important because it's alright
548 * for blk-crypto to see stale values - they only cause blk-crypto to
549 * believe that a crypto capability isn't supported when it actually is (which
550 * might result in blk-crypto-fallback being used if available, or the bio being
551 * failed).
552 */
553void blk_crypto_update_capabilities(struct blk_crypto_profile *dst,
554 const struct blk_crypto_profile *src)
555{
556 memcpy(dst->modes_supported, src->modes_supported,
557 sizeof(dst->modes_supported));
558
559 dst->max_dun_bytes_supported = src->max_dun_bytes_supported;
560}
561EXPORT_SYMBOL_GPL(blk_crypto_update_capabilities);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2019 Google LLC
4 */
5
6/**
7 * DOC: blk-crypto profiles
8 *
9 * 'struct blk_crypto_profile' contains all generic inline encryption-related
10 * state for a particular inline encryption device. blk_crypto_profile serves
11 * as the way that drivers for inline encryption hardware expose their crypto
12 * capabilities and certain functions (e.g., functions to program and evict
13 * keys) to upper layers. Device drivers that want to support inline encryption
14 * construct a crypto profile, then associate it with the disk's request_queue.
15 *
16 * If the device has keyslots, then its blk_crypto_profile also handles managing
17 * these keyslots in a device-independent way, using the driver-provided
18 * functions to program and evict keys as needed. This includes keeping track
19 * of which key and how many I/O requests are using each keyslot, getting
20 * keyslots for I/O requests, and handling key eviction requests.
21 *
22 * For more information, see Documentation/block/inline-encryption.rst.
23 */
24
25#define pr_fmt(fmt) "blk-crypto: " fmt
26
27#include <linux/blk-crypto-profile.h>
28#include <linux/device.h>
29#include <linux/atomic.h>
30#include <linux/mutex.h>
31#include <linux/pm_runtime.h>
32#include <linux/wait.h>
33#include <linux/blkdev.h>
34#include <linux/blk-integrity.h>
35#include "blk-crypto-internal.h"
36
37struct blk_crypto_keyslot {
38 atomic_t slot_refs;
39 struct list_head idle_slot_node;
40 struct hlist_node hash_node;
41 const struct blk_crypto_key *key;
42 struct blk_crypto_profile *profile;
43};
44
45static inline void blk_crypto_hw_enter(struct blk_crypto_profile *profile)
46{
47 /*
48 * Calling into the driver requires profile->lock held and the device
49 * resumed. But we must resume the device first, since that can acquire
50 * and release profile->lock via blk_crypto_reprogram_all_keys().
51 */
52 if (profile->dev)
53 pm_runtime_get_sync(profile->dev);
54 down_write(&profile->lock);
55}
56
57static inline void blk_crypto_hw_exit(struct blk_crypto_profile *profile)
58{
59 up_write(&profile->lock);
60 if (profile->dev)
61 pm_runtime_put_sync(profile->dev);
62}
63
64/**
65 * blk_crypto_profile_init() - Initialize a blk_crypto_profile
66 * @profile: the blk_crypto_profile to initialize
67 * @num_slots: the number of keyslots
68 *
69 * Storage drivers must call this when starting to set up a blk_crypto_profile,
70 * before filling in additional fields.
71 *
72 * Return: 0 on success, or else a negative error code.
73 */
74int blk_crypto_profile_init(struct blk_crypto_profile *profile,
75 unsigned int num_slots)
76{
77 unsigned int slot;
78 unsigned int i;
79 unsigned int slot_hashtable_size;
80
81 memset(profile, 0, sizeof(*profile));
82
83 /*
84 * profile->lock of an underlying device can nest inside profile->lock
85 * of a device-mapper device, so use a dynamic lock class to avoid
86 * false-positive lockdep reports.
87 */
88 lockdep_register_key(&profile->lockdep_key);
89 __init_rwsem(&profile->lock, "&profile->lock", &profile->lockdep_key);
90
91 if (num_slots == 0)
92 return 0;
93
94 /* Initialize keyslot management data. */
95
96 profile->slots = kvcalloc(num_slots, sizeof(profile->slots[0]),
97 GFP_KERNEL);
98 if (!profile->slots)
99 goto err_destroy;
100
101 profile->num_slots = num_slots;
102
103 init_waitqueue_head(&profile->idle_slots_wait_queue);
104 INIT_LIST_HEAD(&profile->idle_slots);
105
106 for (slot = 0; slot < num_slots; slot++) {
107 profile->slots[slot].profile = profile;
108 list_add_tail(&profile->slots[slot].idle_slot_node,
109 &profile->idle_slots);
110 }
111
112 spin_lock_init(&profile->idle_slots_lock);
113
114 slot_hashtable_size = roundup_pow_of_two(num_slots);
115 /*
116 * hash_ptr() assumes bits != 0, so ensure the hash table has at least 2
117 * buckets. This only makes a difference when there is only 1 keyslot.
118 */
119 if (slot_hashtable_size < 2)
120 slot_hashtable_size = 2;
121
122 profile->log_slot_ht_size = ilog2(slot_hashtable_size);
123 profile->slot_hashtable =
124 kvmalloc_array(slot_hashtable_size,
125 sizeof(profile->slot_hashtable[0]), GFP_KERNEL);
126 if (!profile->slot_hashtable)
127 goto err_destroy;
128 for (i = 0; i < slot_hashtable_size; i++)
129 INIT_HLIST_HEAD(&profile->slot_hashtable[i]);
130
131 return 0;
132
133err_destroy:
134 blk_crypto_profile_destroy(profile);
135 return -ENOMEM;
136}
137EXPORT_SYMBOL_GPL(blk_crypto_profile_init);
138
139static void blk_crypto_profile_destroy_callback(void *profile)
140{
141 blk_crypto_profile_destroy(profile);
142}
143
144/**
145 * devm_blk_crypto_profile_init() - Resource-managed blk_crypto_profile_init()
146 * @dev: the device which owns the blk_crypto_profile
147 * @profile: the blk_crypto_profile to initialize
148 * @num_slots: the number of keyslots
149 *
150 * Like blk_crypto_profile_init(), but causes blk_crypto_profile_destroy() to be
151 * called automatically on driver detach.
152 *
153 * Return: 0 on success, or else a negative error code.
154 */
155int devm_blk_crypto_profile_init(struct device *dev,
156 struct blk_crypto_profile *profile,
157 unsigned int num_slots)
158{
159 int err = blk_crypto_profile_init(profile, num_slots);
160
161 if (err)
162 return err;
163
164 return devm_add_action_or_reset(dev,
165 blk_crypto_profile_destroy_callback,
166 profile);
167}
168EXPORT_SYMBOL_GPL(devm_blk_crypto_profile_init);
169
170static inline struct hlist_head *
171blk_crypto_hash_bucket_for_key(struct blk_crypto_profile *profile,
172 const struct blk_crypto_key *key)
173{
174 return &profile->slot_hashtable[
175 hash_ptr(key, profile->log_slot_ht_size)];
176}
177
178static void
179blk_crypto_remove_slot_from_lru_list(struct blk_crypto_keyslot *slot)
180{
181 struct blk_crypto_profile *profile = slot->profile;
182 unsigned long flags;
183
184 spin_lock_irqsave(&profile->idle_slots_lock, flags);
185 list_del(&slot->idle_slot_node);
186 spin_unlock_irqrestore(&profile->idle_slots_lock, flags);
187}
188
189static struct blk_crypto_keyslot *
190blk_crypto_find_keyslot(struct blk_crypto_profile *profile,
191 const struct blk_crypto_key *key)
192{
193 const struct hlist_head *head =
194 blk_crypto_hash_bucket_for_key(profile, key);
195 struct blk_crypto_keyslot *slotp;
196
197 hlist_for_each_entry(slotp, head, hash_node) {
198 if (slotp->key == key)
199 return slotp;
200 }
201 return NULL;
202}
203
204static struct blk_crypto_keyslot *
205blk_crypto_find_and_grab_keyslot(struct blk_crypto_profile *profile,
206 const struct blk_crypto_key *key)
207{
208 struct blk_crypto_keyslot *slot;
209
210 slot = blk_crypto_find_keyslot(profile, key);
211 if (!slot)
212 return NULL;
213 if (atomic_inc_return(&slot->slot_refs) == 1) {
214 /* Took first reference to this slot; remove it from LRU list */
215 blk_crypto_remove_slot_from_lru_list(slot);
216 }
217 return slot;
218}
219
220/**
221 * blk_crypto_keyslot_index() - Get the index of a keyslot
222 * @slot: a keyslot that blk_crypto_get_keyslot() returned
223 *
224 * Return: the 0-based index of the keyslot within the device's keyslots.
225 */
226unsigned int blk_crypto_keyslot_index(struct blk_crypto_keyslot *slot)
227{
228 return slot - slot->profile->slots;
229}
230EXPORT_SYMBOL_GPL(blk_crypto_keyslot_index);
231
232/**
233 * blk_crypto_get_keyslot() - Get a keyslot for a key, if needed.
234 * @profile: the crypto profile of the device the key will be used on
235 * @key: the key that will be used
236 * @slot_ptr: If a keyslot is allocated, an opaque pointer to the keyslot struct
237 * will be stored here. blk_crypto_put_keyslot() must be called
238 * later to release it. Otherwise, NULL will be stored here.
239 *
240 * If the device has keyslots, this gets a keyslot that's been programmed with
241 * the specified key. If the key is already in a slot, this reuses it;
242 * otherwise this waits for a slot to become idle and programs the key into it.
243 *
244 * Context: Process context. Takes and releases profile->lock.
245 * Return: BLK_STS_OK on success, meaning that either a keyslot was allocated or
246 * one wasn't needed; or a blk_status_t error on failure.
247 */
248blk_status_t blk_crypto_get_keyslot(struct blk_crypto_profile *profile,
249 const struct blk_crypto_key *key,
250 struct blk_crypto_keyslot **slot_ptr)
251{
252 struct blk_crypto_keyslot *slot;
253 int slot_idx;
254 int err;
255
256 *slot_ptr = NULL;
257
258 /*
259 * If the device has no concept of "keyslots", then there is no need to
260 * get one.
261 */
262 if (profile->num_slots == 0)
263 return BLK_STS_OK;
264
265 down_read(&profile->lock);
266 slot = blk_crypto_find_and_grab_keyslot(profile, key);
267 up_read(&profile->lock);
268 if (slot)
269 goto success;
270
271 for (;;) {
272 blk_crypto_hw_enter(profile);
273 slot = blk_crypto_find_and_grab_keyslot(profile, key);
274 if (slot) {
275 blk_crypto_hw_exit(profile);
276 goto success;
277 }
278
279 /*
280 * If we're here, that means there wasn't a slot that was
281 * already programmed with the key. So try to program it.
282 */
283 if (!list_empty(&profile->idle_slots))
284 break;
285
286 blk_crypto_hw_exit(profile);
287 wait_event(profile->idle_slots_wait_queue,
288 !list_empty(&profile->idle_slots));
289 }
290
291 slot = list_first_entry(&profile->idle_slots, struct blk_crypto_keyslot,
292 idle_slot_node);
293 slot_idx = blk_crypto_keyslot_index(slot);
294
295 err = profile->ll_ops.keyslot_program(profile, key, slot_idx);
296 if (err) {
297 wake_up(&profile->idle_slots_wait_queue);
298 blk_crypto_hw_exit(profile);
299 return errno_to_blk_status(err);
300 }
301
302 /* Move this slot to the hash list for the new key. */
303 if (slot->key)
304 hlist_del(&slot->hash_node);
305 slot->key = key;
306 hlist_add_head(&slot->hash_node,
307 blk_crypto_hash_bucket_for_key(profile, key));
308
309 atomic_set(&slot->slot_refs, 1);
310
311 blk_crypto_remove_slot_from_lru_list(slot);
312
313 blk_crypto_hw_exit(profile);
314success:
315 *slot_ptr = slot;
316 return BLK_STS_OK;
317}
318
319/**
320 * blk_crypto_put_keyslot() - Release a reference to a keyslot
321 * @slot: The keyslot to release the reference of
322 *
323 * Context: Any context.
324 */
325void blk_crypto_put_keyslot(struct blk_crypto_keyslot *slot)
326{
327 struct blk_crypto_profile *profile = slot->profile;
328 unsigned long flags;
329
330 if (atomic_dec_and_lock_irqsave(&slot->slot_refs,
331 &profile->idle_slots_lock, flags)) {
332 list_add_tail(&slot->idle_slot_node, &profile->idle_slots);
333 spin_unlock_irqrestore(&profile->idle_slots_lock, flags);
334 wake_up(&profile->idle_slots_wait_queue);
335 }
336}
337
338/**
339 * __blk_crypto_cfg_supported() - Check whether the given crypto profile
340 * supports the given crypto configuration.
341 * @profile: the crypto profile to check
342 * @cfg: the crypto configuration to check for
343 *
344 * Return: %true if @profile supports the given @cfg.
345 */
346bool __blk_crypto_cfg_supported(struct blk_crypto_profile *profile,
347 const struct blk_crypto_config *cfg)
348{
349 if (!profile)
350 return false;
351 if (!(profile->modes_supported[cfg->crypto_mode] & cfg->data_unit_size))
352 return false;
353 if (profile->max_dun_bytes_supported < cfg->dun_bytes)
354 return false;
355 return true;
356}
357
358/*
359 * This is an internal function that evicts a key from an inline encryption
360 * device that can be either a real device or the blk-crypto-fallback "device".
361 * It is used only by blk_crypto_evict_key(); see that function for details.
362 */
363int __blk_crypto_evict_key(struct blk_crypto_profile *profile,
364 const struct blk_crypto_key *key)
365{
366 struct blk_crypto_keyslot *slot;
367 int err;
368
369 if (profile->num_slots == 0) {
370 if (profile->ll_ops.keyslot_evict) {
371 blk_crypto_hw_enter(profile);
372 err = profile->ll_ops.keyslot_evict(profile, key, -1);
373 blk_crypto_hw_exit(profile);
374 return err;
375 }
376 return 0;
377 }
378
379 blk_crypto_hw_enter(profile);
380 slot = blk_crypto_find_keyslot(profile, key);
381 if (!slot) {
382 /*
383 * Not an error, since a key not in use by I/O is not guaranteed
384 * to be in a keyslot. There can be more keys than keyslots.
385 */
386 err = 0;
387 goto out;
388 }
389
390 if (WARN_ON_ONCE(atomic_read(&slot->slot_refs) != 0)) {
391 /* BUG: key is still in use by I/O */
392 err = -EBUSY;
393 goto out_remove;
394 }
395 err = profile->ll_ops.keyslot_evict(profile, key,
396 blk_crypto_keyslot_index(slot));
397out_remove:
398 /*
399 * Callers free the key even on error, so unlink the key from the hash
400 * table and clear slot->key even on error.
401 */
402 hlist_del(&slot->hash_node);
403 slot->key = NULL;
404out:
405 blk_crypto_hw_exit(profile);
406 return err;
407}
408
409/**
410 * blk_crypto_reprogram_all_keys() - Re-program all keyslots.
411 * @profile: The crypto profile
412 *
413 * Re-program all keyslots that are supposed to have a key programmed. This is
414 * intended only for use by drivers for hardware that loses its keys on reset.
415 *
416 * Context: Process context. Takes and releases profile->lock.
417 */
418void blk_crypto_reprogram_all_keys(struct blk_crypto_profile *profile)
419{
420 unsigned int slot;
421
422 if (profile->num_slots == 0)
423 return;
424
425 /* This is for device initialization, so don't resume the device */
426 down_write(&profile->lock);
427 for (slot = 0; slot < profile->num_slots; slot++) {
428 const struct blk_crypto_key *key = profile->slots[slot].key;
429 int err;
430
431 if (!key)
432 continue;
433
434 err = profile->ll_ops.keyslot_program(profile, key, slot);
435 WARN_ON(err);
436 }
437 up_write(&profile->lock);
438}
439EXPORT_SYMBOL_GPL(blk_crypto_reprogram_all_keys);
440
441void blk_crypto_profile_destroy(struct blk_crypto_profile *profile)
442{
443 if (!profile)
444 return;
445 lockdep_unregister_key(&profile->lockdep_key);
446 kvfree(profile->slot_hashtable);
447 kvfree_sensitive(profile->slots,
448 sizeof(profile->slots[0]) * profile->num_slots);
449 memzero_explicit(profile, sizeof(*profile));
450}
451EXPORT_SYMBOL_GPL(blk_crypto_profile_destroy);
452
453bool blk_crypto_register(struct blk_crypto_profile *profile,
454 struct request_queue *q)
455{
456 if (blk_integrity_queue_supports_integrity(q)) {
457 pr_warn("Integrity and hardware inline encryption are not supported together. Disabling hardware inline encryption.\n");
458 return false;
459 }
460 q->crypto_profile = profile;
461 return true;
462}
463EXPORT_SYMBOL_GPL(blk_crypto_register);
464
465/**
466 * blk_crypto_intersect_capabilities() - restrict supported crypto capabilities
467 * by child device
468 * @parent: the crypto profile for the parent device
469 * @child: the crypto profile for the child device, or NULL
470 *
471 * This clears all crypto capabilities in @parent that aren't set in @child. If
472 * @child is NULL, then this clears all parent capabilities.
473 *
474 * Only use this when setting up the crypto profile for a layered device, before
475 * it's been exposed yet.
476 */
477void blk_crypto_intersect_capabilities(struct blk_crypto_profile *parent,
478 const struct blk_crypto_profile *child)
479{
480 if (child) {
481 unsigned int i;
482
483 parent->max_dun_bytes_supported =
484 min(parent->max_dun_bytes_supported,
485 child->max_dun_bytes_supported);
486 for (i = 0; i < ARRAY_SIZE(child->modes_supported); i++)
487 parent->modes_supported[i] &= child->modes_supported[i];
488 } else {
489 parent->max_dun_bytes_supported = 0;
490 memset(parent->modes_supported, 0,
491 sizeof(parent->modes_supported));
492 }
493}
494EXPORT_SYMBOL_GPL(blk_crypto_intersect_capabilities);
495
496/**
497 * blk_crypto_has_capabilities() - Check whether @target supports at least all
498 * the crypto capabilities that @reference does.
499 * @target: the target profile
500 * @reference: the reference profile
501 *
502 * Return: %true if @target supports all the crypto capabilities of @reference.
503 */
504bool blk_crypto_has_capabilities(const struct blk_crypto_profile *target,
505 const struct blk_crypto_profile *reference)
506{
507 int i;
508
509 if (!reference)
510 return true;
511
512 if (!target)
513 return false;
514
515 for (i = 0; i < ARRAY_SIZE(target->modes_supported); i++) {
516 if (reference->modes_supported[i] & ~target->modes_supported[i])
517 return false;
518 }
519
520 if (reference->max_dun_bytes_supported >
521 target->max_dun_bytes_supported)
522 return false;
523
524 return true;
525}
526EXPORT_SYMBOL_GPL(blk_crypto_has_capabilities);
527
528/**
529 * blk_crypto_update_capabilities() - Update the capabilities of a crypto
530 * profile to match those of another crypto
531 * profile.
532 * @dst: The crypto profile whose capabilities to update.
533 * @src: The crypto profile whose capabilities this function will update @dst's
534 * capabilities to.
535 *
536 * Blk-crypto requires that crypto capabilities that were
537 * advertised when a bio was created continue to be supported by the
538 * device until that bio is ended. This is turn means that a device cannot
539 * shrink its advertised crypto capabilities without any explicit
540 * synchronization with upper layers. So if there's no such explicit
541 * synchronization, @src must support all the crypto capabilities that
542 * @dst does (i.e. we need blk_crypto_has_capabilities(@src, @dst)).
543 *
544 * Note also that as long as the crypto capabilities are being expanded, the
545 * order of updates becoming visible is not important because it's alright
546 * for blk-crypto to see stale values - they only cause blk-crypto to
547 * believe that a crypto capability isn't supported when it actually is (which
548 * might result in blk-crypto-fallback being used if available, or the bio being
549 * failed).
550 */
551void blk_crypto_update_capabilities(struct blk_crypto_profile *dst,
552 const struct blk_crypto_profile *src)
553{
554 memcpy(dst->modes_supported, src->modes_supported,
555 sizeof(dst->modes_supported));
556
557 dst->max_dun_bytes_supported = src->max_dun_bytes_supported;
558}
559EXPORT_SYMBOL_GPL(blk_crypto_update_capabilities);