forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
578 lines
16 KiB
578 lines
16 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* Copyright 2019 Google LLC |
|
*/ |
|
|
|
/** |
|
* DOC: The Keyslot Manager |
|
* |
|
* Many devices with inline encryption support have a limited number of "slots" |
|
* into which encryption contexts may be programmed, and requests can be tagged |
|
* with a slot number to specify the key to use for en/decryption. |
|
* |
|
* As the number of slots is limited, and programming keys is expensive on |
|
* many inline encryption hardware, we don't want to program the same key into |
|
* multiple slots - if multiple requests are using the same key, we want to |
|
* program just one slot with that key and use that slot for all requests. |
|
* |
|
* The keyslot manager manages these keyslots appropriately, and also acts as |
|
* an abstraction between the inline encryption hardware and the upper layers. |
|
* |
|
* Lower layer devices will set up a keyslot manager in their request queue |
|
* and tell it how to perform device specific operations like programming/ |
|
* evicting keys from keyslots. |
|
* |
|
* Upper layers will call blk_ksm_get_slot_for_key() to program a |
|
* key into some slot in the inline encryption hardware. |
|
*/ |
|
|
|
#define pr_fmt(fmt) "blk-crypto: " fmt |
|
|
|
#include <linux/keyslot-manager.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> |
|
|
|
struct blk_ksm_keyslot { |
|
atomic_t slot_refs; |
|
struct list_head idle_slot_node; |
|
struct hlist_node hash_node; |
|
const struct blk_crypto_key *key; |
|
struct blk_keyslot_manager *ksm; |
|
}; |
|
|
|
static inline void blk_ksm_hw_enter(struct blk_keyslot_manager *ksm) |
|
{ |
|
/* |
|
* Calling into the driver requires ksm->lock held and the device |
|
* resumed. But we must resume the device first, since that can acquire |
|
* and release ksm->lock via blk_ksm_reprogram_all_keys(). |
|
*/ |
|
if (ksm->dev) |
|
pm_runtime_get_sync(ksm->dev); |
|
down_write(&ksm->lock); |
|
} |
|
|
|
static inline void blk_ksm_hw_exit(struct blk_keyslot_manager *ksm) |
|
{ |
|
up_write(&ksm->lock); |
|
if (ksm->dev) |
|
pm_runtime_put_sync(ksm->dev); |
|
} |
|
|
|
static inline bool blk_ksm_is_passthrough(struct blk_keyslot_manager *ksm) |
|
{ |
|
return ksm->num_slots == 0; |
|
} |
|
|
|
/** |
|
* blk_ksm_init() - Initialize a keyslot manager |
|
* @ksm: The keyslot_manager to initialize. |
|
* @num_slots: The number of key slots to manage. |
|
* |
|
* Allocate memory for keyslots and initialize a keyslot manager. Called by |
|
* e.g. storage drivers to set up a keyslot manager in their request_queue. |
|
* |
|
* Return: 0 on success, or else a negative error code. |
|
*/ |
|
int blk_ksm_init(struct blk_keyslot_manager *ksm, unsigned int num_slots) |
|
{ |
|
unsigned int slot; |
|
unsigned int i; |
|
unsigned int slot_hashtable_size; |
|
|
|
memset(ksm, 0, sizeof(*ksm)); |
|
|
|
if (num_slots == 0) |
|
return -EINVAL; |
|
|
|
ksm->slots = kvcalloc(num_slots, sizeof(ksm->slots[0]), GFP_KERNEL); |
|
if (!ksm->slots) |
|
return -ENOMEM; |
|
|
|
ksm->num_slots = num_slots; |
|
|
|
init_rwsem(&ksm->lock); |
|
|
|
init_waitqueue_head(&ksm->idle_slots_wait_queue); |
|
INIT_LIST_HEAD(&ksm->idle_slots); |
|
|
|
for (slot = 0; slot < num_slots; slot++) { |
|
ksm->slots[slot].ksm = ksm; |
|
list_add_tail(&ksm->slots[slot].idle_slot_node, |
|
&ksm->idle_slots); |
|
} |
|
|
|
spin_lock_init(&ksm->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; |
|
|
|
ksm->log_slot_ht_size = ilog2(slot_hashtable_size); |
|
ksm->slot_hashtable = kvmalloc_array(slot_hashtable_size, |
|
sizeof(ksm->slot_hashtable[0]), |
|
GFP_KERNEL); |
|
if (!ksm->slot_hashtable) |
|
goto err_destroy_ksm; |
|
for (i = 0; i < slot_hashtable_size; i++) |
|
INIT_HLIST_HEAD(&ksm->slot_hashtable[i]); |
|
|
|
return 0; |
|
|
|
err_destroy_ksm: |
|
blk_ksm_destroy(ksm); |
|
return -ENOMEM; |
|
} |
|
EXPORT_SYMBOL_GPL(blk_ksm_init); |
|
|
|
static void blk_ksm_destroy_callback(void *ksm) |
|
{ |
|
blk_ksm_destroy(ksm); |
|
} |
|
|
|
/** |
|
* devm_blk_ksm_init() - Resource-managed blk_ksm_init() |
|
* @dev: The device which owns the blk_keyslot_manager. |
|
* @ksm: The blk_keyslot_manager to initialize. |
|
* @num_slots: The number of key slots to manage. |
|
* |
|
* Like blk_ksm_init(), but causes blk_ksm_destroy() to be called automatically |
|
* on driver detach. |
|
* |
|
* Return: 0 on success, or else a negative error code. |
|
*/ |
|
int devm_blk_ksm_init(struct device *dev, struct blk_keyslot_manager *ksm, |
|
unsigned int num_slots) |
|
{ |
|
int err = blk_ksm_init(ksm, num_slots); |
|
|
|
if (err) |
|
return err; |
|
|
|
return devm_add_action_or_reset(dev, blk_ksm_destroy_callback, ksm); |
|
} |
|
EXPORT_SYMBOL_GPL(devm_blk_ksm_init); |
|
|
|
static inline struct hlist_head * |
|
blk_ksm_hash_bucket_for_key(struct blk_keyslot_manager *ksm, |
|
const struct blk_crypto_key *key) |
|
{ |
|
return &ksm->slot_hashtable[hash_ptr(key, ksm->log_slot_ht_size)]; |
|
} |
|
|
|
static void blk_ksm_remove_slot_from_lru_list(struct blk_ksm_keyslot *slot) |
|
{ |
|
struct blk_keyslot_manager *ksm = slot->ksm; |
|
unsigned long flags; |
|
|
|
spin_lock_irqsave(&ksm->idle_slots_lock, flags); |
|
list_del(&slot->idle_slot_node); |
|
spin_unlock_irqrestore(&ksm->idle_slots_lock, flags); |
|
} |
|
|
|
static struct blk_ksm_keyslot *blk_ksm_find_keyslot( |
|
struct blk_keyslot_manager *ksm, |
|
const struct blk_crypto_key *key) |
|
{ |
|
const struct hlist_head *head = blk_ksm_hash_bucket_for_key(ksm, key); |
|
struct blk_ksm_keyslot *slotp; |
|
|
|
hlist_for_each_entry(slotp, head, hash_node) { |
|
if (slotp->key == key) |
|
return slotp; |
|
} |
|
return NULL; |
|
} |
|
|
|
static struct blk_ksm_keyslot *blk_ksm_find_and_grab_keyslot( |
|
struct blk_keyslot_manager *ksm, |
|
const struct blk_crypto_key *key) |
|
{ |
|
struct blk_ksm_keyslot *slot; |
|
|
|
slot = blk_ksm_find_keyslot(ksm, 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_ksm_remove_slot_from_lru_list(slot); |
|
} |
|
return slot; |
|
} |
|
|
|
unsigned int blk_ksm_get_slot_idx(struct blk_ksm_keyslot *slot) |
|
{ |
|
return slot - slot->ksm->slots; |
|
} |
|
EXPORT_SYMBOL_GPL(blk_ksm_get_slot_idx); |
|
|
|
/** |
|
* blk_ksm_get_slot_for_key() - Program a key into a keyslot. |
|
* @ksm: The keyslot manager to program the key into. |
|
* @key: Pointer to the key object to program, including the raw key, crypto |
|
* mode, and data unit size. |
|
* @slot_ptr: A pointer to return the pointer of the allocated keyslot. |
|
* |
|
* Get a keyslot that's been programmed with the specified key. If one already |
|
* exists, return it with incremented refcount. Otherwise, wait for a keyslot |
|
* to become idle and program it. |
|
* |
|
* Context: Process context. Takes and releases ksm->lock. |
|
* Return: BLK_STS_OK on success (and keyslot is set to the pointer of the |
|
* allocated keyslot), or some other blk_status_t otherwise (and |
|
* keyslot is set to NULL). |
|
*/ |
|
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) |
|
{ |
|
struct blk_ksm_keyslot *slot; |
|
int slot_idx; |
|
int err; |
|
|
|
*slot_ptr = NULL; |
|
|
|
if (blk_ksm_is_passthrough(ksm)) |
|
return BLK_STS_OK; |
|
|
|
down_read(&ksm->lock); |
|
slot = blk_ksm_find_and_grab_keyslot(ksm, key); |
|
up_read(&ksm->lock); |
|
if (slot) |
|
goto success; |
|
|
|
for (;;) { |
|
blk_ksm_hw_enter(ksm); |
|
slot = blk_ksm_find_and_grab_keyslot(ksm, key); |
|
if (slot) { |
|
blk_ksm_hw_exit(ksm); |
|
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(&ksm->idle_slots)) |
|
break; |
|
|
|
blk_ksm_hw_exit(ksm); |
|
wait_event(ksm->idle_slots_wait_queue, |
|
!list_empty(&ksm->idle_slots)); |
|
} |
|
|
|
slot = list_first_entry(&ksm->idle_slots, struct blk_ksm_keyslot, |
|
idle_slot_node); |
|
slot_idx = blk_ksm_get_slot_idx(slot); |
|
|
|
err = ksm->ksm_ll_ops.keyslot_program(ksm, key, slot_idx); |
|
if (err) { |
|
wake_up(&ksm->idle_slots_wait_queue); |
|
blk_ksm_hw_exit(ksm); |
|
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_ksm_hash_bucket_for_key(ksm, key)); |
|
|
|
atomic_set(&slot->slot_refs, 1); |
|
|
|
blk_ksm_remove_slot_from_lru_list(slot); |
|
|
|
blk_ksm_hw_exit(ksm); |
|
success: |
|
*slot_ptr = slot; |
|
return BLK_STS_OK; |
|
} |
|
|
|
/** |
|
* blk_ksm_put_slot() - Release a reference to a slot |
|
* @slot: The keyslot to release the reference of. |
|
* |
|
* Context: Any context. |
|
*/ |
|
void blk_ksm_put_slot(struct blk_ksm_keyslot *slot) |
|
{ |
|
struct blk_keyslot_manager *ksm; |
|
unsigned long flags; |
|
|
|
if (!slot) |
|
return; |
|
|
|
ksm = slot->ksm; |
|
|
|
if (atomic_dec_and_lock_irqsave(&slot->slot_refs, |
|
&ksm->idle_slots_lock, flags)) { |
|
list_add_tail(&slot->idle_slot_node, &ksm->idle_slots); |
|
spin_unlock_irqrestore(&ksm->idle_slots_lock, flags); |
|
wake_up(&ksm->idle_slots_wait_queue); |
|
} |
|
} |
|
|
|
/** |
|
* blk_ksm_crypto_cfg_supported() - Find out if a crypto configuration is |
|
* supported by a ksm. |
|
* @ksm: The keyslot manager to check |
|
* @cfg: The crypto configuration to check for. |
|
* |
|
* Checks for crypto_mode/data unit size/dun bytes support. |
|
* |
|
* Return: Whether or not this ksm supports the specified crypto config. |
|
*/ |
|
bool blk_ksm_crypto_cfg_supported(struct blk_keyslot_manager *ksm, |
|
const struct blk_crypto_config *cfg) |
|
{ |
|
if (!ksm) |
|
return false; |
|
if (!(ksm->crypto_modes_supported[cfg->crypto_mode] & |
|
cfg->data_unit_size)) |
|
return false; |
|
if (ksm->max_dun_bytes_supported < cfg->dun_bytes) |
|
return false; |
|
return true; |
|
} |
|
|
|
/** |
|
* blk_ksm_evict_key() - Evict a key from the lower layer device. |
|
* @ksm: The keyslot manager to evict from |
|
* @key: The key to evict |
|
* |
|
* Find the keyslot that the specified key was programmed into, and evict that |
|
* slot from the lower layer device. The slot must not be in use by any |
|
* in-flight IO when this function is called. |
|
* |
|
* Context: Process context. Takes and releases ksm->lock. |
|
* Return: 0 on success or if there's no keyslot with the specified key, -EBUSY |
|
* if the keyslot is still in use, or another -errno value on other |
|
* error. |
|
*/ |
|
int blk_ksm_evict_key(struct blk_keyslot_manager *ksm, |
|
const struct blk_crypto_key *key) |
|
{ |
|
struct blk_ksm_keyslot *slot; |
|
int err = 0; |
|
|
|
if (blk_ksm_is_passthrough(ksm)) { |
|
if (ksm->ksm_ll_ops.keyslot_evict) { |
|
blk_ksm_hw_enter(ksm); |
|
err = ksm->ksm_ll_ops.keyslot_evict(ksm, key, -1); |
|
blk_ksm_hw_exit(ksm); |
|
return err; |
|
} |
|
return 0; |
|
} |
|
|
|
blk_ksm_hw_enter(ksm); |
|
slot = blk_ksm_find_keyslot(ksm, key); |
|
if (!slot) |
|
goto out_unlock; |
|
|
|
if (WARN_ON_ONCE(atomic_read(&slot->slot_refs) != 0)) { |
|
err = -EBUSY; |
|
goto out_unlock; |
|
} |
|
err = ksm->ksm_ll_ops.keyslot_evict(ksm, key, |
|
blk_ksm_get_slot_idx(slot)); |
|
if (err) |
|
goto out_unlock; |
|
|
|
hlist_del(&slot->hash_node); |
|
slot->key = NULL; |
|
err = 0; |
|
out_unlock: |
|
blk_ksm_hw_exit(ksm); |
|
return err; |
|
} |
|
|
|
/** |
|
* blk_ksm_reprogram_all_keys() - Re-program all keyslots. |
|
* @ksm: The keyslot manager |
|
* |
|
* 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 ksm->lock. |
|
*/ |
|
void blk_ksm_reprogram_all_keys(struct blk_keyslot_manager *ksm) |
|
{ |
|
unsigned int slot; |
|
|
|
if (blk_ksm_is_passthrough(ksm)) |
|
return; |
|
|
|
/* This is for device initialization, so don't resume the device */ |
|
down_write(&ksm->lock); |
|
for (slot = 0; slot < ksm->num_slots; slot++) { |
|
const struct blk_crypto_key *key = ksm->slots[slot].key; |
|
int err; |
|
|
|
if (!key) |
|
continue; |
|
|
|
err = ksm->ksm_ll_ops.keyslot_program(ksm, key, slot); |
|
WARN_ON(err); |
|
} |
|
up_write(&ksm->lock); |
|
} |
|
EXPORT_SYMBOL_GPL(blk_ksm_reprogram_all_keys); |
|
|
|
void blk_ksm_destroy(struct blk_keyslot_manager *ksm) |
|
{ |
|
if (!ksm) |
|
return; |
|
kvfree(ksm->slot_hashtable); |
|
kvfree_sensitive(ksm->slots, sizeof(ksm->slots[0]) * ksm->num_slots); |
|
memzero_explicit(ksm, sizeof(*ksm)); |
|
} |
|
EXPORT_SYMBOL_GPL(blk_ksm_destroy); |
|
|
|
bool blk_ksm_register(struct blk_keyslot_manager *ksm, 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->ksm = ksm; |
|
return true; |
|
} |
|
EXPORT_SYMBOL_GPL(blk_ksm_register); |
|
|
|
void blk_ksm_unregister(struct request_queue *q) |
|
{ |
|
q->ksm = NULL; |
|
} |
|
|
|
/** |
|
* blk_ksm_intersect_modes() - restrict supported modes by child device |
|
* @parent: The keyslot manager for parent device |
|
* @child: The keyslot manager for child device, or NULL |
|
* |
|
* Clear any crypto mode support bits in @parent that aren't set in @child. |
|
* If @child is NULL, then all parent bits are cleared. |
|
* |
|
* Only use this when setting up the keyslot manager for a layered device, |
|
* before it's been exposed yet. |
|
*/ |
|
void blk_ksm_intersect_modes(struct blk_keyslot_manager *parent, |
|
const struct blk_keyslot_manager *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->crypto_modes_supported); |
|
i++) { |
|
parent->crypto_modes_supported[i] &= |
|
child->crypto_modes_supported[i]; |
|
} |
|
} else { |
|
parent->max_dun_bytes_supported = 0; |
|
memset(parent->crypto_modes_supported, 0, |
|
sizeof(parent->crypto_modes_supported)); |
|
} |
|
} |
|
EXPORT_SYMBOL_GPL(blk_ksm_intersect_modes); |
|
|
|
/** |
|
* blk_ksm_is_superset() - Check if a KSM supports a superset of crypto modes |
|
* and DUN bytes that another KSM supports. Here, |
|
* "superset" refers to the mathematical meaning of the |
|
* word - i.e. if two KSMs have the *same* capabilities, |
|
* they *are* considered supersets of each other. |
|
* @ksm_superset: The KSM that we want to verify is a superset |
|
* @ksm_subset: The KSM that we want to verify is a subset |
|
* |
|
* Return: True if @ksm_superset supports a superset of the crypto modes and DUN |
|
* bytes that @ksm_subset supports. |
|
*/ |
|
bool blk_ksm_is_superset(struct blk_keyslot_manager *ksm_superset, |
|
struct blk_keyslot_manager *ksm_subset) |
|
{ |
|
int i; |
|
|
|
if (!ksm_subset) |
|
return true; |
|
|
|
if (!ksm_superset) |
|
return false; |
|
|
|
for (i = 0; i < ARRAY_SIZE(ksm_superset->crypto_modes_supported); i++) { |
|
if (ksm_subset->crypto_modes_supported[i] & |
|
(~ksm_superset->crypto_modes_supported[i])) { |
|
return false; |
|
} |
|
} |
|
|
|
if (ksm_subset->max_dun_bytes_supported > |
|
ksm_superset->max_dun_bytes_supported) { |
|
return false; |
|
} |
|
|
|
return true; |
|
} |
|
EXPORT_SYMBOL_GPL(blk_ksm_is_superset); |
|
|
|
/** |
|
* blk_ksm_update_capabilities() - Update the restrictions of a KSM to those of |
|
* another KSM |
|
* @target_ksm: The KSM whose restrictions to update. |
|
* @reference_ksm: The KSM to whose restrictions this function will update |
|
* @target_ksm's restrictions 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, @reference_ksm must support all the crypto capabilities that |
|
* @target_ksm does |
|
* (i.e. we need blk_ksm_is_superset(@reference_ksm, @target_ksm) == true). |
|
* |
|
* 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_ksm_update_capabilities(struct blk_keyslot_manager *target_ksm, |
|
struct blk_keyslot_manager *reference_ksm) |
|
{ |
|
memcpy(target_ksm->crypto_modes_supported, |
|
reference_ksm->crypto_modes_supported, |
|
sizeof(target_ksm->crypto_modes_supported)); |
|
|
|
target_ksm->max_dun_bytes_supported = |
|
reference_ksm->max_dun_bytes_supported; |
|
} |
|
EXPORT_SYMBOL_GPL(blk_ksm_update_capabilities); |
|
|
|
/** |
|
* blk_ksm_init_passthrough() - Init a passthrough keyslot manager |
|
* @ksm: The keyslot manager to init |
|
* |
|
* Initialize a passthrough keyslot manager. |
|
* Called by e.g. storage drivers to set up a keyslot manager in their |
|
* request_queue, when the storage driver wants to manage its keys by itself. |
|
* This is useful for inline encryption hardware that doesn't have the concept |
|
* of keyslots, and for layered devices. |
|
*/ |
|
void blk_ksm_init_passthrough(struct blk_keyslot_manager *ksm) |
|
{ |
|
memset(ksm, 0, sizeof(*ksm)); |
|
init_rwsem(&ksm->lock); |
|
} |
|
EXPORT_SYMBOL_GPL(blk_ksm_init_passthrough);
|
|
|