/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright 2019 Google LLC
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*/
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#ifndef __LINUX_KEYSLOT_MANAGER_H
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#define __LINUX_KEYSLOT_MANAGER_H
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#include <linux/bio.h>
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#include <linux/blk-crypto.h>
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/* Inline crypto feature bits. Must set at least one. */
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enum {
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/* Support for standard software-specified keys */
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BLK_CRYPTO_FEATURE_STANDARD_KEYS = BIT(0),
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/* Support for hardware-wrapped keys */
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BLK_CRYPTO_FEATURE_WRAPPED_KEYS = BIT(1),
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};
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struct blk_keyslot_manager;
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/**
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* struct blk_ksm_ll_ops - functions to manage keyslots in hardware
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* @keyslot_program: Program the specified key into the specified slot in the
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* inline encryption hardware.
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* @keyslot_evict: Evict key from the specified keyslot in the hardware.
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* The key is provided so that e.g. dm layers can evict
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* keys from the devices that they map over.
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* Returns 0 on success, -errno otherwise.
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* @derive_raw_secret: (Optional) Derive a software secret from a
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* hardware-wrapped key. Returns 0 on success, -EOPNOTSUPP
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* if unsupported on the hardware, or another -errno code.
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*
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* This structure should be provided by storage device drivers when they set up
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* a keyslot manager - this structure holds the function ptrs that the keyslot
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* manager will use to manipulate keyslots in the hardware.
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*/
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struct blk_ksm_ll_ops {
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int (*keyslot_program)(struct blk_keyslot_manager *ksm,
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const struct blk_crypto_key *key,
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unsigned int slot);
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int (*keyslot_evict)(struct blk_keyslot_manager *ksm,
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const struct blk_crypto_key *key,
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unsigned int slot);
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int (*derive_raw_secret)(struct blk_keyslot_manager *ksm,
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const u8 *wrapped_key,
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unsigned int wrapped_key_size,
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u8 *secret, unsigned int secret_size);
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};
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struct blk_keyslot_manager {
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/*
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* The struct blk_ksm_ll_ops that this keyslot manager will use
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* to perform operations like programming and evicting keys on the
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* device
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*/
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struct blk_ksm_ll_ops ksm_ll_ops;
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/*
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* The maximum number of bytes supported for specifying the data unit
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* number.
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*/
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unsigned int max_dun_bytes_supported;
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/*
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* The supported features as a bitmask of BLK_CRYPTO_FEATURE_* flags.
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* Most drivers should set BLK_CRYPTO_FEATURE_STANDARD_KEYS here.
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*/
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unsigned int features;
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/*
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* Array of size BLK_ENCRYPTION_MODE_MAX of bitmasks that represents
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* whether a crypto mode and data unit size are supported. The i'th
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* bit of crypto_mode_supported[crypto_mode] is set iff a data unit
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* size of (1 << i) is supported. We only support data unit sizes
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* that are powers of 2.
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*/
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unsigned int crypto_modes_supported[BLK_ENCRYPTION_MODE_MAX];
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/* Device for runtime power management (NULL if none) */
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struct device *dev;
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/* Here onwards are *private* fields for internal keyslot manager use */
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unsigned int num_slots;
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/* Protects programming and evicting keys from the device */
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struct rw_semaphore lock;
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/* List of idle slots, with least recently used slot at front */
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wait_queue_head_t idle_slots_wait_queue;
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struct list_head idle_slots;
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spinlock_t idle_slots_lock;
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/*
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* Hash table which maps struct *blk_crypto_key to keyslots, so that we
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* can find a key's keyslot in O(1) time rather than O(num_slots).
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* Protected by 'lock'.
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*/
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struct hlist_head *slot_hashtable;
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unsigned int log_slot_ht_size;
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/* Per-keyslot data */
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struct blk_ksm_keyslot *slots;
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};
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int blk_ksm_init(struct blk_keyslot_manager *ksm, unsigned int num_slots);
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int devm_blk_ksm_init(struct device *dev, struct blk_keyslot_manager *ksm,
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unsigned int num_slots);
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blk_status_t blk_ksm_get_slot_for_key(struct blk_keyslot_manager *ksm,
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const struct blk_crypto_key *key,
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struct blk_ksm_keyslot **slot_ptr);
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unsigned int blk_ksm_get_slot_idx(struct blk_ksm_keyslot *slot);
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void blk_ksm_put_slot(struct blk_ksm_keyslot *slot);
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bool blk_ksm_crypto_cfg_supported(struct blk_keyslot_manager *ksm,
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const struct blk_crypto_config *cfg);
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int blk_ksm_evict_key(struct blk_keyslot_manager *ksm,
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const struct blk_crypto_key *key);
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void blk_ksm_reprogram_all_keys(struct blk_keyslot_manager *ksm);
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void blk_ksm_destroy(struct blk_keyslot_manager *ksm);
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int blk_ksm_derive_raw_secret(struct blk_keyslot_manager *ksm,
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const u8 *wrapped_key,
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unsigned int wrapped_key_size,
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u8 *secret, unsigned int secret_size);
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void blk_ksm_intersect_modes(struct blk_keyslot_manager *parent,
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const struct blk_keyslot_manager *child);
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void blk_ksm_init_passthrough(struct blk_keyslot_manager *ksm);
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bool blk_ksm_is_superset(struct blk_keyslot_manager *ksm_superset,
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struct blk_keyslot_manager *ksm_subset);
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void blk_ksm_update_capabilities(struct blk_keyslot_manager *target_ksm,
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struct blk_keyslot_manager *reference_ksm);
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#endif /* __LINUX_KEYSLOT_MANAGER_H */
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