| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright 2019 Google LLC |
| */ |
| |
| /** |
| * DOC: blk-crypto profiles |
| * |
| * 'struct blk_crypto_profile' contains all generic inline encryption-related |
| * state for a particular inline encryption device. blk_crypto_profile serves |
| * as the way that drivers for inline encryption hardware expose their crypto |
| * capabilities and certain functions (e.g., functions to program and evict |
| * keys) to upper layers. Device drivers that want to support inline encryption |
| * construct a crypto profile, then associate it with the disk's request_queue. |
| * |
| * If the device has keyslots, then its blk_crypto_profile also handles managing |
| * these keyslots in a device-independent way, using the driver-provided |
| * functions to program and evict keys as needed. This includes keeping track |
| * of which key and how many I/O requests are using each keyslot, getting |
| * keyslots for I/O requests, and handling key eviction requests. |
| * |
| * For more information, see Documentation/block/inline-encryption.rst. |
| */ |
| |
| #define pr_fmt(fmt) "blk-crypto: " fmt |
| |
| #include <linux/blk-crypto-profile.h> |
| #include <linux/device.h> |
| #include <linux/atomic.h> |
| #include <linux/mutex.h> |
| #include <linux/pm_runtime.h> |
| #include <linux/wait.h> |
| #include <linux/blkdev.h> |
| #include <linux/blk-integrity.h> |
| #include "blk-crypto-internal.h" |
| |
| struct blk_crypto_keyslot { |
| atomic_t slot_refs; |
| struct list_head idle_slot_node; |
| struct hlist_node hash_node; |
| const struct blk_crypto_key *key; |
| struct blk_crypto_profile *profile; |
| }; |
| |
| static inline void blk_crypto_hw_enter(struct blk_crypto_profile *profile) |
| { |
| /* |
| * Calling into the driver requires profile->lock held and the device |
| * resumed. But we must resume the device first, since that can acquire |
| * and release profile->lock via blk_crypto_reprogram_all_keys(). |
| */ |
| if (profile->dev) |
| pm_runtime_get_sync(profile->dev); |
| down_write(&profile->lock); |
| } |
| |
| static inline void blk_crypto_hw_exit(struct blk_crypto_profile *profile) |
| { |
| up_write(&profile->lock); |
| if (profile->dev) |
| pm_runtime_put_sync(profile->dev); |
| } |
| |
| /** |
| * blk_crypto_profile_init() - Initialize a blk_crypto_profile |
| * @profile: the blk_crypto_profile to initialize |
| * @num_slots: the number of keyslots |
| * |
| * Storage drivers must call this when starting to set up a blk_crypto_profile, |
| * before filling in additional fields. |
| * |
| * Return: 0 on success, or else a negative error code. |
| */ |
| int blk_crypto_profile_init(struct blk_crypto_profile *profile, |
| unsigned int num_slots) |
| { |
| unsigned int slot; |
| unsigned int i; |
| unsigned int slot_hashtable_size; |
| |
| memset(profile, 0, sizeof(*profile)); |
| init_rwsem(&profile->lock); |
| |
| if (num_slots == 0) |
| return 0; |
| |
| /* Initialize keyslot management data. */ |
| |
| profile->slots = kvcalloc(num_slots, sizeof(profile->slots[0]), |
| GFP_KERNEL); |
| if (!profile->slots) |
| return -ENOMEM; |
| |
| profile->num_slots = num_slots; |
| |
| init_waitqueue_head(&profile->idle_slots_wait_queue); |
| INIT_LIST_HEAD(&profile->idle_slots); |
| |
| for (slot = 0; slot < num_slots; slot++) { |
| profile->slots[slot].profile = profile; |
| list_add_tail(&profile->slots[slot].idle_slot_node, |
| &profile->idle_slots); |
| } |
| |
| spin_lock_init(&profile->idle_slots_lock); |
| |
| slot_hashtable_size = roundup_pow_of_two(num_slots); |
| /* |
| * hash_ptr() assumes bits != 0, so ensure the hash table has at least 2 |
| * buckets. This only makes a difference when there is only 1 keyslot. |
| */ |
| if (slot_hashtable_size < 2) |
| slot_hashtable_size = 2; |
| |
| profile->log_slot_ht_size = ilog2(slot_hashtable_size); |
| profile->slot_hashtable = |
| kvmalloc_array(slot_hashtable_size, |
| sizeof(profile->slot_hashtable[0]), GFP_KERNEL); |
| if (!profile->slot_hashtable) |
| goto err_destroy; |
| for (i = 0; i < slot_hashtable_size; i++) |
| INIT_HLIST_HEAD(&profile->slot_hashtable[i]); |
| |
| return 0; |
| |
| err_destroy: |
| blk_crypto_profile_destroy(profile); |
| return -ENOMEM; |
| } |
| EXPORT_SYMBOL_GPL(blk_crypto_profile_init); |
| |
| static void blk_crypto_profile_destroy_callback(void *profile) |
| { |
| blk_crypto_profile_destroy(profile); |
| } |
| |
| /** |
| * devm_blk_crypto_profile_init() - Resource-managed blk_crypto_profile_init() |
| * @dev: the device which owns the blk_crypto_profile |
| * @profile: the blk_crypto_profile to initialize |
| * @num_slots: the number of keyslots |
| * |
| * Like blk_crypto_profile_init(), but causes blk_crypto_profile_destroy() to be |
| * called automatically on driver detach. |
| * |
| * Return: 0 on success, or else a negative error code. |
| */ |
| int devm_blk_crypto_profile_init(struct device *dev, |
| struct blk_crypto_profile *profile, |
| unsigned int num_slots) |
| { |
| int err = blk_crypto_profile_init(profile, num_slots); |
| |
| if (err) |
| return err; |
| |
| return devm_add_action_or_reset(dev, |
| blk_crypto_profile_destroy_callback, |
| profile); |
| } |
| EXPORT_SYMBOL_GPL(devm_blk_crypto_profile_init); |
| |
| static inline struct hlist_head * |
| blk_crypto_hash_bucket_for_key(struct blk_crypto_profile *profile, |
| const struct blk_crypto_key *key) |
| { |
| return &profile->slot_hashtable[ |
| hash_ptr(key, profile->log_slot_ht_size)]; |
| } |
| |
| static void |
| blk_crypto_remove_slot_from_lru_list(struct blk_crypto_keyslot *slot) |
| { |
| struct blk_crypto_profile *profile = slot->profile; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&profile->idle_slots_lock, flags); |
| list_del(&slot->idle_slot_node); |
| spin_unlock_irqrestore(&profile->idle_slots_lock, flags); |
| } |
| |
| static struct blk_crypto_keyslot * |
| blk_crypto_find_keyslot(struct blk_crypto_profile *profile, |
| const struct blk_crypto_key *key) |
| { |
| const struct hlist_head *head = |
| blk_crypto_hash_bucket_for_key(profile, key); |
| struct blk_crypto_keyslot *slotp; |
| |
| hlist_for_each_entry(slotp, head, hash_node) { |
| if (slotp->key == key) |
| return slotp; |
| } |
| return NULL; |
| } |
| |
| static struct blk_crypto_keyslot * |
| blk_crypto_find_and_grab_keyslot(struct blk_crypto_profile *profile, |
| const struct blk_crypto_key *key) |
| { |
| struct blk_crypto_keyslot *slot; |
| |
| slot = blk_crypto_find_keyslot(profile, key); |
| if (!slot) |
| return NULL; |
| if (atomic_inc_return(&slot->slot_refs) == 1) { |
| /* Took first reference to this slot; remove it from LRU list */ |
| blk_crypto_remove_slot_from_lru_list(slot); |
| } |
| return slot; |
| } |
| |
| /** |
| * blk_crypto_keyslot_index() - Get the index of a keyslot |
| * @slot: a keyslot that blk_crypto_get_keyslot() returned |
| * |
| * Return: the 0-based index of the keyslot within the device's keyslots. |
| */ |
| unsigned int blk_crypto_keyslot_index(struct blk_crypto_keyslot *slot) |
| { |
| return slot - slot->profile->slots; |
| } |
| EXPORT_SYMBOL_GPL(blk_crypto_keyslot_index); |
| |
| /** |
| * blk_crypto_get_keyslot() - Get a keyslot for a key, if needed. |
| * @profile: the crypto profile of the device the key will be used on |
| * @key: the key that will be used |
| * @slot_ptr: If a keyslot is allocated, an opaque pointer to the keyslot struct |
| * will be stored here. blk_crypto_put_keyslot() must be called |
| * later to release it. Otherwise, NULL will be stored here. |
| * |
| * If the device has keyslots, this gets a keyslot that's been programmed with |
| * the specified key. If the key is already in a slot, this reuses it; |
| * otherwise this waits for a slot to become idle and programs the key into it. |
| * |
| * Context: Process context. Takes and releases profile->lock. |
| * Return: BLK_STS_OK on success, meaning that either a keyslot was allocated or |
| * one wasn't needed; or a blk_status_t error on failure. |
| */ |
| blk_status_t blk_crypto_get_keyslot(struct blk_crypto_profile *profile, |
| const struct blk_crypto_key *key, |
| struct blk_crypto_keyslot **slot_ptr) |
| { |
| struct blk_crypto_keyslot *slot; |
| int slot_idx; |
| int err; |
| |
| *slot_ptr = NULL; |
| |
| /* |
| * If the device has no concept of "keyslots", then there is no need to |
| * get one. |
| */ |
| if (profile->num_slots == 0) |
| return BLK_STS_OK; |
| |
| down_read(&profile->lock); |
| slot = blk_crypto_find_and_grab_keyslot(profile, key); |
| up_read(&profile->lock); |
| if (slot) |
| goto success; |
| |
| for (;;) { |
| blk_crypto_hw_enter(profile); |
| slot = blk_crypto_find_and_grab_keyslot(profile, key); |
| if (slot) { |
| blk_crypto_hw_exit(profile); |
| goto success; |
| } |
| |
| /* |
| * If we're here, that means there wasn't a slot that was |
| * already programmed with the key. So try to program it. |
| */ |
| if (!list_empty(&profile->idle_slots)) |
| break; |
| |
| blk_crypto_hw_exit(profile); |
| wait_event(profile->idle_slots_wait_queue, |
| !list_empty(&profile->idle_slots)); |
| } |
| |
| slot = list_first_entry(&profile->idle_slots, struct blk_crypto_keyslot, |
| idle_slot_node); |
| slot_idx = blk_crypto_keyslot_index(slot); |
| |
| err = profile->ll_ops.keyslot_program(profile, key, slot_idx); |
| if (err) { |
| wake_up(&profile->idle_slots_wait_queue); |
| blk_crypto_hw_exit(profile); |
| return errno_to_blk_status(err); |
| } |
| |
| /* Move this slot to the hash list for the new key. */ |
| if (slot->key) |
| hlist_del(&slot->hash_node); |
| slot->key = key; |
| hlist_add_head(&slot->hash_node, |
| blk_crypto_hash_bucket_for_key(profile, key)); |
| |
| atomic_set(&slot->slot_refs, 1); |
| |
| blk_crypto_remove_slot_from_lru_list(slot); |
| |
| blk_crypto_hw_exit(profile); |
| success: |
| *slot_ptr = slot; |
| return BLK_STS_OK; |
| } |
| |
| /** |
| * blk_crypto_put_keyslot() - Release a reference to a keyslot |
| * @slot: The keyslot to release the reference of |
| * |
| * Context: Any context. |
| */ |
| void blk_crypto_put_keyslot(struct blk_crypto_keyslot *slot) |
| { |
| struct blk_crypto_profile *profile = slot->profile; |
| unsigned long flags; |
| |
| if (atomic_dec_and_lock_irqsave(&slot->slot_refs, |
| &profile->idle_slots_lock, flags)) { |
| list_add_tail(&slot->idle_slot_node, &profile->idle_slots); |
| spin_unlock_irqrestore(&profile->idle_slots_lock, flags); |
| wake_up(&profile->idle_slots_wait_queue); |
| } |
| } |
| |
| /** |
| * __blk_crypto_cfg_supported() - Check whether the given crypto profile |
| * supports the given crypto configuration. |
| * @profile: the crypto profile to check |
| * @cfg: the crypto configuration to check for |
| * |
| * Return: %true if @profile supports the given @cfg. |
| */ |
| bool __blk_crypto_cfg_supported(struct blk_crypto_profile *profile, |
| const struct blk_crypto_config *cfg) |
| { |
| if (!profile) |
| return false; |
| if (!(profile->modes_supported[cfg->crypto_mode] & cfg->data_unit_size)) |
| return false; |
| if (profile->max_dun_bytes_supported < cfg->dun_bytes) |
| return false; |
| if (!(profile->key_types_supported & cfg->key_type)) |
| return false; |
| return true; |
| } |
| |
| /* |
| * This is an internal function that evicts a key from an inline encryption |
| * device that can be either a real device or the blk-crypto-fallback "device". |
| * It is used only by blk_crypto_evict_key(); see that function for details. |
| */ |
| int __blk_crypto_evict_key(struct blk_crypto_profile *profile, |
| const struct blk_crypto_key *key) |
| { |
| struct blk_crypto_keyslot *slot; |
| int err; |
| |
| if (profile->num_slots == 0) { |
| if (profile->ll_ops.keyslot_evict) { |
| blk_crypto_hw_enter(profile); |
| err = profile->ll_ops.keyslot_evict(profile, key, -1); |
| blk_crypto_hw_exit(profile); |
| return err; |
| } |
| return 0; |
| } |
| |
| blk_crypto_hw_enter(profile); |
| slot = blk_crypto_find_keyslot(profile, key); |
| if (!slot) { |
| /* |
| * Not an error, since a key not in use by I/O is not guaranteed |
| * to be in a keyslot. There can be more keys than keyslots. |
| */ |
| err = 0; |
| goto out; |
| } |
| |
| if (WARN_ON_ONCE(atomic_read(&slot->slot_refs) != 0)) { |
| /* BUG: key is still in use by I/O */ |
| err = -EBUSY; |
| goto out_remove; |
| } |
| err = profile->ll_ops.keyslot_evict(profile, key, |
| blk_crypto_keyslot_index(slot)); |
| out_remove: |
| /* |
| * Callers free the key even on error, so unlink the key from the hash |
| * table and clear slot->key even on error. |
| */ |
| hlist_del(&slot->hash_node); |
| slot->key = NULL; |
| out: |
| blk_crypto_hw_exit(profile); |
| return err; |
| } |
| |
| /** |
| * blk_crypto_reprogram_all_keys() - Re-program all keyslots. |
| * @profile: The crypto profile |
| * |
| * Re-program all keyslots that are supposed to have a key programmed. This is |
| * intended only for use by drivers for hardware that loses its keys on reset. |
| * |
| * Context: Process context. Takes and releases profile->lock. |
| */ |
| void blk_crypto_reprogram_all_keys(struct blk_crypto_profile *profile) |
| { |
| unsigned int slot; |
| |
| if (profile->num_slots == 0) |
| return; |
| |
| /* This is for device initialization, so don't resume the device */ |
| down_write(&profile->lock); |
| for (slot = 0; slot < profile->num_slots; slot++) { |
| const struct blk_crypto_key *key = profile->slots[slot].key; |
| int err; |
| |
| if (!key) |
| continue; |
| |
| err = profile->ll_ops.keyslot_program(profile, key, slot); |
| WARN_ON(err); |
| } |
| up_write(&profile->lock); |
| } |
| EXPORT_SYMBOL_GPL(blk_crypto_reprogram_all_keys); |
| |
| void blk_crypto_profile_destroy(struct blk_crypto_profile *profile) |
| { |
| if (!profile) |
| return; |
| kvfree(profile->slot_hashtable); |
| kvfree_sensitive(profile->slots, |
| sizeof(profile->slots[0]) * profile->num_slots); |
| memzero_explicit(profile, sizeof(*profile)); |
| } |
| EXPORT_SYMBOL_GPL(blk_crypto_profile_destroy); |
| |
| bool blk_crypto_register(struct blk_crypto_profile *profile, |
| struct request_queue *q) |
| { |
| if (blk_integrity_queue_supports_integrity(q)) { |
| pr_warn("Integrity and hardware inline encryption are not supported together. Disabling hardware inline encryption.\n"); |
| return false; |
| } |
| q->crypto_profile = profile; |
| return true; |
| } |
| EXPORT_SYMBOL_GPL(blk_crypto_register); |
| |
| /** |
| * blk_crypto_derive_sw_secret() - Derive software secret from wrapped key |
| * @bdev: a block device that supports hardware-wrapped keys |
| * @eph_key: the hardware-wrapped key in ephemerally-wrapped form |
| * @eph_key_size: size of @eph_key in bytes |
| * @sw_secret: (output) the software secret |
| * |
| * Given a hardware-wrapped key in ephemerally-wrapped form (the same form that |
| * it is used for I/O), ask the hardware to derive the secret which software can |
| * use for cryptographic tasks other than inline encryption. This secret is |
| * guaranteed to be cryptographically isolated from the inline encryption key, |
| * i.e. derived with a different KDF context. |
| * |
| * Return: 0 on success, -EOPNOTSUPP if the block device doesn't support |
| * hardware-wrapped keys, -EBADMSG if the key isn't a valid |
| * hardware-wrapped key, or another -errno code. |
| */ |
| int blk_crypto_derive_sw_secret(struct block_device *bdev, |
| const u8 *eph_key, size_t eph_key_size, |
| u8 sw_secret[BLK_CRYPTO_SW_SECRET_SIZE]) |
| { |
| struct blk_crypto_profile *profile = |
| bdev_get_queue(bdev)->crypto_profile; |
| int err; |
| |
| if (!profile) |
| return -EOPNOTSUPP; |
| if (!(profile->key_types_supported & BLK_CRYPTO_KEY_TYPE_HW_WRAPPED)) |
| return -EOPNOTSUPP; |
| if (!profile->ll_ops.derive_sw_secret) |
| return -EOPNOTSUPP; |
| blk_crypto_hw_enter(profile); |
| err = profile->ll_ops.derive_sw_secret(profile, eph_key, eph_key_size, |
| sw_secret); |
| blk_crypto_hw_exit(profile); |
| return err; |
| } |
| EXPORT_SYMBOL_GPL(blk_crypto_derive_sw_secret); |
| |
| /** |
| * blk_crypto_intersect_capabilities() - restrict supported crypto capabilities |
| * by child device |
| * @parent: the crypto profile for the parent device |
| * @child: the crypto profile for the child device, or NULL |
| * |
| * This clears all crypto capabilities in @parent that aren't set in @child. If |
| * @child is NULL, then this clears all parent capabilities. |
| * |
| * Only use this when setting up the crypto profile for a layered device, before |
| * it's been exposed yet. |
| */ |
| void blk_crypto_intersect_capabilities(struct blk_crypto_profile *parent, |
| const struct blk_crypto_profile *child) |
| { |
| if (child) { |
| unsigned int i; |
| |
| parent->max_dun_bytes_supported = |
| min(parent->max_dun_bytes_supported, |
| child->max_dun_bytes_supported); |
| for (i = 0; i < ARRAY_SIZE(child->modes_supported); i++) |
| parent->modes_supported[i] &= child->modes_supported[i]; |
| parent->key_types_supported &= child->key_types_supported; |
| } else { |
| parent->max_dun_bytes_supported = 0; |
| memset(parent->modes_supported, 0, |
| sizeof(parent->modes_supported)); |
| parent->key_types_supported = 0; |
| } |
| } |
| EXPORT_SYMBOL_GPL(blk_crypto_intersect_capabilities); |
| |
| /** |
| * blk_crypto_has_capabilities() - Check whether @target supports at least all |
| * the crypto capabilities that @reference does. |
| * @target: the target profile |
| * @reference: the reference profile |
| * |
| * Return: %true if @target supports all the crypto capabilities of @reference. |
| */ |
| bool blk_crypto_has_capabilities(const struct blk_crypto_profile *target, |
| const struct blk_crypto_profile *reference) |
| { |
| int i; |
| |
| if (!reference) |
| return true; |
| |
| if (!target) |
| return false; |
| |
| for (i = 0; i < ARRAY_SIZE(target->modes_supported); i++) { |
| if (reference->modes_supported[i] & ~target->modes_supported[i]) |
| return false; |
| } |
| |
| if (reference->max_dun_bytes_supported > |
| target->max_dun_bytes_supported) |
| return false; |
| |
| if (reference->key_types_supported & ~target->key_types_supported) |
| return false; |
| |
| return true; |
| } |
| EXPORT_SYMBOL_GPL(blk_crypto_has_capabilities); |
| |
| /** |
| * blk_crypto_update_capabilities() - Update the capabilities of a crypto |
| * profile to match those of another crypto |
| * profile. |
| * @dst: The crypto profile whose capabilities to update. |
| * @src: The crypto profile whose capabilities this function will update @dst's |
| * capabilities to. |
| * |
| * Blk-crypto requires that crypto capabilities that were |
| * advertised when a bio was created continue to be supported by the |
| * device until that bio is ended. This is turn means that a device cannot |
| * shrink its advertised crypto capabilities without any explicit |
| * synchronization with upper layers. So if there's no such explicit |
| * synchronization, @src must support all the crypto capabilities that |
| * @dst does (i.e. we need blk_crypto_has_capabilities(@src, @dst)). |
| * |
| * Note also that as long as the crypto capabilities are being expanded, the |
| * order of updates becoming visible is not important because it's alright |
| * for blk-crypto to see stale values - they only cause blk-crypto to |
| * believe that a crypto capability isn't supported when it actually is (which |
| * might result in blk-crypto-fallback being used if available, or the bio being |
| * failed). |
| */ |
| void blk_crypto_update_capabilities(struct blk_crypto_profile *dst, |
| const struct blk_crypto_profile *src) |
| { |
| memcpy(dst->modes_supported, src->modes_supported, |
| sizeof(dst->modes_supported)); |
| |
| dst->max_dun_bytes_supported = src->max_dun_bytes_supported; |
| dst->key_types_supported = src->key_types_supported; |
| } |
| EXPORT_SYMBOL_GPL(blk_crypto_update_capabilities); |