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