e124323186
The call to pm_runtime_get_sync() in ufshcd_program_key() can deadlock
because it waits for the UFS controller to be resumed, but it can itself
be reached while resuming the UFS controller via:
- ufshcd_runtime_resume()
- ufshcd_resume()
- ufshcd_reset_and_restore()
- ufshcd_host_reset_and_restore()
- ufshcd_hba_enable()
- ufshcd_hba_execute_hce()
- ufshcd_hba_start()
- ufshcd_crypto_enable()
- keyslot_manager_reprogram_all_keys()
- ufshcd_crypto_keyslot_program()
- ufshcd_program_key()
But pm_runtime_get_sync() *is* needed when evicting a key. Also, on
pre-4.20 kernels it's needed when programming a keyslot for a bio since
the block layer used to resume the device in a different place.
Thus, it's hard for drivers to know what to do in .keyslot_program() and
.keyslot_evict(). In old kernels it may even be impossible unless we
were to pass more information down from the keyslot_manager.
There's also another possible deadlock: keyslot programming and eviction
take ksm->lock for write and then resume the device, which may result in
ksm->lock being taken again via the above call stack. To fix this, we
should resume the device before taking ksm->lock.
Fix these problems by moving to a better design where the block layer
(namely, the keyslot manager) handles runtime power management instead
of drivers. This is analogous to the block layer's existing runtime
power management support (blk-pm), which handles resuming devices when
bios are submitted to them so that drivers don't need to handle it.
Test: Tested on coral with:
echo 5 > /sys/bus/platform/devices/1d84000.ufshc/rpm_lvl
sleep 30
touch /data && sync # hangs before this fix
Also verified via kvm-xfstests that blk-crypto-fallback continues
to work both with and without CONFIG_PM=y.
Bug: 137270441
Bug: 149368295
Change-Id: I6bc9fb81854afe7edf490d71796ee68a61f7cbc8
Signed-off-by: Eric Biggers <ebiggers@google.com>
88 lines
3.0 KiB
C
88 lines
3.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
/*
|
|
* Copyright 2019 Google LLC
|
|
*/
|
|
|
|
#ifndef __LINUX_KEYSLOT_MANAGER_H
|
|
#define __LINUX_KEYSLOT_MANAGER_H
|
|
|
|
#include <linux/bio.h>
|
|
|
|
#ifdef CONFIG_BLK_INLINE_ENCRYPTION
|
|
|
|
struct keyslot_manager;
|
|
|
|
/**
|
|
* struct keyslot_mgmt_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 keyslot_mgmt_ll_ops {
|
|
int (*keyslot_program)(struct keyslot_manager *ksm,
|
|
const struct blk_crypto_key *key,
|
|
unsigned int slot);
|
|
int (*keyslot_evict)(struct keyslot_manager *ksm,
|
|
const struct blk_crypto_key *key,
|
|
unsigned int slot);
|
|
int (*derive_raw_secret)(struct keyslot_manager *ksm,
|
|
const u8 *wrapped_key,
|
|
unsigned int wrapped_key_size,
|
|
u8 *secret, unsigned int secret_size);
|
|
};
|
|
|
|
struct keyslot_manager *keyslot_manager_create(
|
|
struct device *dev,
|
|
unsigned int num_slots,
|
|
const struct keyslot_mgmt_ll_ops *ksm_ops,
|
|
const unsigned int crypto_mode_supported[BLK_ENCRYPTION_MODE_MAX],
|
|
void *ll_priv_data);
|
|
|
|
int keyslot_manager_get_slot_for_key(struct keyslot_manager *ksm,
|
|
const struct blk_crypto_key *key);
|
|
|
|
void keyslot_manager_get_slot(struct keyslot_manager *ksm, unsigned int slot);
|
|
|
|
void keyslot_manager_put_slot(struct keyslot_manager *ksm, unsigned int slot);
|
|
|
|
bool keyslot_manager_crypto_mode_supported(struct keyslot_manager *ksm,
|
|
enum blk_crypto_mode_num crypto_mode,
|
|
unsigned int data_unit_size);
|
|
|
|
int keyslot_manager_evict_key(struct keyslot_manager *ksm,
|
|
const struct blk_crypto_key *key);
|
|
|
|
void keyslot_manager_reprogram_all_keys(struct keyslot_manager *ksm);
|
|
|
|
void *keyslot_manager_private(struct keyslot_manager *ksm);
|
|
|
|
void keyslot_manager_destroy(struct keyslot_manager *ksm);
|
|
|
|
struct keyslot_manager *keyslot_manager_create_passthrough(
|
|
struct device *dev,
|
|
const struct keyslot_mgmt_ll_ops *ksm_ops,
|
|
const unsigned int crypto_mode_supported[BLK_ENCRYPTION_MODE_MAX],
|
|
void *ll_priv_data);
|
|
|
|
void keyslot_manager_intersect_modes(struct keyslot_manager *parent,
|
|
const struct keyslot_manager *child);
|
|
|
|
int keyslot_manager_derive_raw_secret(struct keyslot_manager *ksm,
|
|
const u8 *wrapped_key,
|
|
unsigned int wrapped_key_size,
|
|
u8 *secret, unsigned int secret_size);
|
|
|
|
#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
|
|
|
|
#endif /* __LINUX_KEYSLOT_MANAGER_H */
|