25b3bc709c
Add a resource-managed variant of blk_ksm_init() so that drivers don't have to worry about calling blk_ksm_destroy(). Note that the implementation uses a custom devres action to call blk_ksm_destroy() rather than switching the two allocations to be directly devres-managed, e.g. with devm_kmalloc(). This is because we need to keep zeroing the memory containing the keyslots when it is freed, and also because we want to continue using kvmalloc() (and there is no devm_kvmalloc()). Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Satya Tangirala <satyat@google.com> Acked-by: Jens Axboe <axboe@kernel.dk> Link: https://lore.kernel.org/r/20210121082155.111333-2-ebiggers@kernel.org Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> (cherry picked from commit 5851d3b042b694839d2241fbb3200ce958135cdf) Bug: 161256007 Change-Id: I3cda7fc5f7509f8d967882a88ca30ddc6f6a0426 Signed-off-by: Eric Biggers <ebiggers@google.com>
148 lines
4.7 KiB
C
148 lines
4.7 KiB
C
/* 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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