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1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright 2019 Google LLC4 */5 6/**7 * DOC: blk-crypto profiles8 *9 * 'struct blk_crypto_profile' contains all generic inline encryption-related10 * state for a particular inline encryption device. blk_crypto_profile serves11 * as the way that drivers for inline encryption hardware expose their crypto12 * capabilities and certain functions (e.g., functions to program and evict13 * keys) to upper layers. Device drivers that want to support inline encryption14 * 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 managing17 * these keyslots in a device-independent way, using the driver-provided18 * functions to program and evict keys as needed. This includes keeping track19 * of which key and how many I/O requests are using each keyslot, getting20 * 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: " fmt26 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 device49 * resumed. But we must resume the device first, since that can acquire50 * 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_profile66 * @profile: the blk_crypto_profile to initialize67 * @num_slots: the number of keyslots68 *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->lock85 * of a device-mapper device, so use a dynamic lock class to avoid86 * 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 2117 * 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_profile147 * @profile: the blk_crypto_profile to initialize148 * @num_slots: the number of keyslots149 *150 * Like blk_crypto_profile_init(), but causes blk_crypto_profile_destroy() to be151 * 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 void179blk_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 keyslot222 * @slot: a keyslot that blk_crypto_get_keyslot() returned223 *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 on235 * @key: the key that will be used236 * @slot_ptr: If a keyslot is allocated, an opaque pointer to the keyslot struct237 * will be stored here. blk_crypto_put_keyslot() must be called238 * 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 with241 * 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 or246 * 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 to260 * 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 was281 * 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 keyslot321 * @slot: The keyslot to release the reference of322 *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 profile340 * supports the given crypto configuration.341 * @profile: the crypto profile to check342 * @cfg: the crypto configuration to check for343 *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 encryption360 * 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 guaranteed384 * 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 hash400 * 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 profile412 *413 * Re-program all keyslots that are supposed to have a key programmed. This is414 * 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 capabilities467 * by child device468 * @parent: the crypto profile for the parent device469 * @child: the crypto profile for the child device, or NULL470 *471 * This clears all crypto capabilities in @parent that aren't set in @child. If472 * @child is NULL, then this clears all parent capabilities.473 *474 * Only use this when setting up the crypto profile for a layered device, before475 * 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 all498 * the crypto capabilities that @reference does.499 * @target: the target profile500 * @reference: the reference profile501 *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 crypto530 * profile to match those of another crypto531 * profile.532 * @dst: The crypto profile whose capabilities to update.533 * @src: The crypto profile whose capabilities this function will update @dst's534 * capabilities to.535 *536 * Blk-crypto requires that crypto capabilities that were537 * advertised when a bio was created continue to be supported by the538 * device until that bio is ended. This is turn means that a device cannot539 * shrink its advertised crypto capabilities without any explicit540 * synchronization with upper layers. So if there's no such explicit541 * synchronization, @src must support all the crypto capabilities that542 * @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, the545 * order of updates becoming visible is not important because it's alright546 * for blk-crypto to see stale values - they only cause blk-crypto to547 * believe that a crypto capability isn't supported when it actually is (which548 * might result in blk-crypto-fallback being used if available, or the bio being549 * 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);560