[f2fs-dev] [PATCH v3 0/8] Inline Encryption Support

[f2fs-dev] [PATCH v3 0/8] Inline Encryption Support

[Satya Tangirala via Linux-f2fs-devel]

This patch series adds support for Inline Encryption to the block layer,
UFS, fscrypt and f2fs.

Inline Encryption hardware allows software to specify an encryption context
(an encryption key, crypto algorithm, data unit num, data unit size, etc.)
along with a data transfer request to a storage device, and the inline
encryption hardware will use that context to en/decrypt the data. The
inline encryption hardware is part of the storage device, and it
conceptually sits on the data path between system memory and the storage
device. Inline Encryption hardware has become increasingly common, and we
want to support it in the kernel.

Inline Encryption hardware implementations often function around the
concept of a limited number of "keyslots", which can hold an encryption
context each. The storage device can be directed to en/decrypt any
particular request with the encryption context stored in any particular
keyslot.

Patch 1 introduces a Keyslot Manager to efficiently manage keyslots.
The keyslot manager also functions as the interface that blk-crypto
(introduced in Path 3), will use to program keys into inline encryption
hardware. For more information on the Keyslot Manager, refer to
documentation found in block/keyslot-manager.c and linux/keyslot-manager.h.

Patch 2 introduces struct bio_crypt_ctx, and a ptr to one in struct bio,
which allows struct bio to represent an encryption context that can be
passed down the storage stack from the filesystem layer to the storage
driver.

Patch 3 introduces blk-crypto. Blk-crypto delegates crypto operations to
inline encryption hardware when available, and also contains a software
fallback to the kernel crypto API. Blk-crypto also makes it possible for
layered devices like device mapper to make use of inline encryption
hardware. Given that blk-crypto works as a software fallback, we are
considering removing file content en/decryption from fscrypt and simply
using blk-crypto in a future patch. For more details on blk-crypto, refer
to Documentation/block/blk-crypto.txt.

Patches 4-6 add support for inline encryption into the UFS driver according
to the JEDEC UFS HCI v2.1 specification. Inline encryption support for
other drivers (like eMMC) may be added in the same way - the device driver
should set up a Keyslot Manager in the device's request_queue (refer to
the UFS crypto additions in ufshcd-crypto.c and ufshcd.c for an example).

Patches 7 and 8 add support to fscrypt and f2fs, so that we have
a complete stack that can make use of inline encryption.

There have been a few patch sets addressing Inline Encryption Support in
the past. Briefly, this patch set differs from those as follows:

1) "crypto: qce: ice: Add support for Inline Crypto Engine"
is specific to certain hardware, while our patch set's Inline
Encryption support for UFS is implemented according to the JEDEC UFS
specification.

2) "scsi: ufs: UFS Host Controller crypto changes" registers inline
encryption support as a kernel crypto algorithm. Our patch views inline
encryption as being fundamentally different from a generic crypto
provider (in that inline encryption is tied to a device), and so does
not use the kernel crypto API to represent inline encryption hardware.

3) "scsi: ufs: add real time/inline crypto support to UFS HCD" requires
the device mapper to work - our patch does not.

Changes v2 => v3:
 - Overhauled keyslot manager's get keyslot logic and optimized LRU.
 - Block crypto en/decryption fallback now supports data unit sizes
   that divide each of the bio's segment's lengths (instead of requiring
   each segment's length to be the same as the data unit size).
 - fscrypt master key is now keyed additionally by super_block and
   ci_ctfm != NULL.
 - all references of "hw encryption" are replaced by inline encryption.
 - address various other review comments from Eric.

Changes v1 => v2:
 - Block layer and UFS changes are split into 3 patches each.
 - We now only have a ptr to a struct bio_crypt_ctx in struct bio, instead
   of the struct itself.
 - struct bio_crypt_ctx no longer has flags.
 - blk-crypto now correctly handles the case when it fails to init
   (because of insufficient memory), but kernel continues to boot.
 - ufshcd-crypto now works on big endian cpus.
 - Many cleanups.

Satya Tangirala (8):
  block: Keyslot Manager for Inline Encryption
  block: Add encryption context to struct bio
  block: blk-crypto for Inline Encryption
  scsi: ufs: UFS driver v2.1 spec crypto additions
  scsi: ufs: UFS crypto API
  scsi: ufs: Add inline encryption support to UFS
  fscrypt: wire up fscrypt to use blk-crypto
  f2fs: Wire up f2fs to use inline encryption via fscrypt

 Documentation/block/inline-encryption.txt | 185 +++++++
 block/Kconfig                             |   8 +
 block/Makefile                            |   2 +
 block/bio-crypt-ctx.c                     | 122 +++++
 block/bio.c                               |  16 +-
 block/blk-core.c                          |  11 +-
 block/blk-crypto.c                        | 585 ++++++++++++++++++++++
 block/blk-merge.c                         |  34 +-
 block/bounce.c                            |   9 +-
 block/keyslot-manager.c                   | 314 ++++++++++++
 drivers/md/dm.c                           |  15 +-
 drivers/scsi/ufs/Kconfig                  |  10 +
 drivers/scsi/ufs/Makefile                 |   1 +
 drivers/scsi/ufs/ufshcd-crypto.c          | 435 ++++++++++++++++
 drivers/scsi/ufs/ufshcd-crypto.h          |  86 ++++
 drivers/scsi/ufs/ufshcd.c                 |  84 +++-
 drivers/scsi/ufs/ufshcd.h                 |  29 ++
 drivers/scsi/ufs/ufshci.h                 |  67 ++-
 fs/crypto/Kconfig                         |   6 +
 fs/crypto/bio.c                           | 138 ++++-
 fs/crypto/crypto.c                        |   4 +
 fs/crypto/fscrypt_private.h               |  11 +
 fs/crypto/keyinfo.c                       |  94 +++-
 fs/crypto/policy.c                        |  10 +
 fs/f2fs/data.c                            |  83 ++-
 fs/f2fs/super.c                           |  13 +-
 include/linux/bio.h                       | 208 ++++++++
 include/linux/blk-crypto.h                |  40 ++
 include/linux/blk_types.h                 |   7 +
 include/linux/blkdev.h                    |   6 +
 include/linux/fscrypt.h                   |  62 +++
 include/linux/keyslot-manager.h           |  75 +++
 include/uapi/linux/fs.h                   |   3 +-
 33 files changed, 2697 insertions(+), 76 deletions(-)
 create mode 100644 Documentation/block/inline-encryption.txt
 create mode 100644 block/bio-crypt-ctx.c
 create mode 100644 block/blk-crypto.c
 create mode 100644 block/keyslot-manager.c
 create mode 100644 drivers/scsi/ufs/ufshcd-crypto.c
 create mode 100644 drivers/scsi/ufs/ufshcd-crypto.h
 create mode 100644 include/linux/blk-crypto.h
 create mode 100644 include/linux/keyslot-manager.h

-- 
2.22.0.410.gd8fdbe21b5-goog



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[f2fs-dev] [PATCH 1/8] block: Keyslot Manager for Inline Encryption

[Satya Tangirala via Linux-f2fs-devel]

Inline Encryption hardware allows software to specify an encryption context
(an encryption key, crypto algorithm, data unit num, data unit size, etc.)
along with a data transfer request to a storage device, and the inline
encryption hardware will use that context to en/decrypt the data. The
inline encryption hardware is part of the storage device, and it
conceptually sits on the data path between system memory and the storage
device.

Inline Encryption hardware implementations often function around the
concept of "keyslots". These implementations often have a limited number
of "keyslots", each of which can hold an encryption context (we say that
an encryption context can be "programmed" into a keyslot). Requests made
to the storage device may have a keyslot associated with them, and the
inline encryption hardware will en/decrypt the data in the requests using
the encryption context programmed into that associated keyslot. As
keyslots are limited, and programming keys may be expensive in many
implementations, and multiple requests may use exactly the same encryption
contexts, we introduce a Keyslot Manager to efficiently manage keyslots.
The keyslot manager also functions as the interface that upper layers will
use to program keys into inline encryption hardware. For more information
on the Keyslot Manager, refer to documentation found in
block/keyslot-manager.c and linux/keyslot-manager.h.

Signed-off-by: Satya Tangirala <satyat@google.com>
---
 block/Kconfig                   |   8 +
 block/Makefile                  |   1 +
 block/keyslot-manager.c         | 314 ++++++++++++++++++++++++++++++++
 include/linux/bio.h             |  11 ++
 include/linux/blkdev.h          |   6 +
 include/linux/keyslot-manager.h |  75 ++++++++
 6 files changed, 415 insertions(+)
 create mode 100644 block/keyslot-manager.c
 create mode 100644 include/linux/keyslot-manager.h

diff --git a/block/Kconfig b/block/Kconfig
index 2466dcc3ef1d..fef7c60f6d8e 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -164,6 +164,14 @@ config BLK_SED_OPAL
 	Enabling this option enables users to setup/unlock/lock
 	Locking ranges for SED devices using the Opal protocol.
 
+config BLK_INLINE_ENCRYPTION
+	bool "Enable inline encryption support in block layer"
+	help
+	  Build the blk-crypto subsystem.
+	  Enabling this lets the block layer handle encryption,
+	  so users can take advantage of inline encryption
+	  hardware if present.
+
 menu "Partition Types"
 
 source "block/partitions/Kconfig"
diff --git a/block/Makefile b/block/Makefile
index eee1b4ceecf9..a72abd61b220 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -35,3 +35,4 @@ obj-$(CONFIG_BLK_DEBUG_FS)	+= blk-mq-debugfs.o
 obj-$(CONFIG_BLK_DEBUG_FS_ZONED)+= blk-mq-debugfs-zoned.o
 obj-$(CONFIG_BLK_SED_OPAL)	+= sed-opal.o
 obj-$(CONFIG_BLK_PM)		+= blk-pm.o
+obj-$(CONFIG_BLK_INLINE_ENCRYPTION)	+= keyslot-manager.o
diff --git a/block/keyslot-manager.c b/block/keyslot-manager.c
new file mode 100644
index 000000000000..22afd00c9235
--- /dev/null
+++ b/block/keyslot-manager.c
@@ -0,0 +1,314 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * keyslot-manager.c
+ *
+ * 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 are 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 keyslot_manager_get_slot_for_key() to program a
+ * key into some slot in the inline encryption hardware.
+ */
+#include <linux/keyslot-manager.h>
+#include <linux/atomic.h>
+#include <linux/mutex.h>
+#include <linux/wait.h>
+
+struct keyslot {
+	atomic_t slot_refs;
+	struct list_head idle_slot_node;
+};
+
+struct keyslot_manager {
+	unsigned int num_slots;
+	atomic_t num_idle_slots;
+	struct keyslot_mgmt_ll_ops ksm_ll_ops;
+	void *ll_priv_data;
+
+	/* 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;
+
+	/* Per-keyslot data */
+	struct keyslot slots[];
+};
+
+/**
+ * keyslot_manager_create() - Create a keyslot manager
+ * @num_slots: The number of key slots to manage.
+ * @ksm_ll_ops: The struct keyslot_mgmt_ll_ops for the device that this keyslot
+ *		manager will use to perform operations like programming and
+ *		evicting keys.
+ * @ll_priv_data: Private data passed as is to the functions in ksm_ll_ops.
+ *
+ * Allocate memory for and initialize a keyslot manager. Called by for e.g.
+ * storage drivers to set up a keyslot manager in their request_queue.
+ *
+ * Context: May sleep
+ * Return: Pointer to constructed keyslot manager or NULL on error.
+ */
+struct keyslot_manager *keyslot_manager_create(unsigned int num_slots,
+				const struct keyslot_mgmt_ll_ops *ksm_ll_ops,
+				void *ll_priv_data)
+{
+	struct keyslot_manager *ksm;
+	int slot;
+
+	if (num_slots == 0)
+		return NULL;
+
+	/* Check that all ops are specified */
+	if (ksm_ll_ops->keyslot_program == NULL ||
+	    ksm_ll_ops->keyslot_evict == NULL ||
+	    ksm_ll_ops->crypt_mode_supported == NULL ||
+	    ksm_ll_ops->keyslot_find == NULL)
+		return NULL;
+
+	ksm = kvzalloc(struct_size(ksm, slots, num_slots), GFP_KERNEL);
+	if (!ksm)
+		return NULL;
+
+	ksm->num_slots = num_slots;
+	atomic_set(&ksm->num_idle_slots, num_slots);
+	ksm->ksm_ll_ops = *ksm_ll_ops;
+	ksm->ll_priv_data = ll_priv_data;
+
+	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++)
+		list_add(&ksm->slots[slot].idle_slot_node, &ksm->idle_slots);
+
+	spin_lock_init(&ksm->idle_slots_lock);
+
+	return ksm;
+}
+EXPORT_SYMBOL(keyslot_manager_create);
+
+static int find_and_grab_keyslot(struct keyslot_manager *ksm, const u8 *key,
+				 enum blk_crypt_mode_num crypt_mode,
+				 unsigned int data_unit_size)
+{
+	int slot;
+	unsigned long flags;
+
+	slot = ksm->ksm_ll_ops.keyslot_find(ksm->ll_priv_data, key,
+					    crypt_mode, data_unit_size);
+	if (slot < 0)
+		return slot;
+	if (WARN_ON(slot >= ksm->num_slots))
+		return -EINVAL;
+	if (atomic_inc_return(&ksm->slots[slot].slot_refs) == 1) {
+		/* Took first reference to this slot; remove it from LRU list */
+		spin_lock_irqsave(&ksm->idle_slots_lock, flags);
+		list_del(&ksm->slots[slot].idle_slot_node);
+		spin_unlock_irqrestore(&ksm->idle_slots_lock, flags);
+		atomic_dec(&ksm->num_idle_slots);
+	}
+	return slot;
+}
+
+/**
+ * keyslot_manager_get_slot_for_key() - Program a key into a keyslot.
+ * @ksm: The keyslot manager to program the key into.
+ * @key: Pointer to the bytes of the key to program. Must be the correct length
+ *      for the chosen @crypt_mode; see blk_crypt_modes in blk-crypto.c.
+ * @crypt_mode: Identifier for the encryption algorithm to use.
+ * @data_unit_size: The data unit size to use for en/decryption.
+ *
+ * Get a keyslot that's been programmed with the specified key, crypt_mode, and
+ * data_unit_size.  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: The keyslot on success, else a -errno value.
+ */
+int keyslot_manager_get_slot_for_key(struct keyslot_manager *ksm,
+				     const u8 *key,
+				     enum blk_crypt_mode_num crypt_mode,
+				     unsigned int data_unit_size)
+{
+	int slot;
+	int err;
+	struct keyslot *idle_slot;
+	unsigned long flags;
+
+	down_read(&ksm->lock);
+	slot = find_and_grab_keyslot(ksm, key, crypt_mode, data_unit_size);
+	up_read(&ksm->lock);
+	if (slot != -ENOKEY)
+		return slot;
+
+	while (true) {
+		down_write(&ksm->lock);
+		slot = find_and_grab_keyslot(ksm, key, crypt_mode,
+					     data_unit_size);
+		if (slot != -ENOKEY) {
+			up_write(&ksm->lock);
+			return slot;
+		}
+
+		/*
+		 * If we're here, that means there wasn't a slot that was
+		 * already programmed with the key. So try to program it.
+		 */
+		if (atomic_read(&ksm->num_idle_slots) > 0)
+			break;
+
+		up_write(&ksm->lock);
+		wait_event(ksm->idle_slots_wait_queue,
+			(atomic_read(&ksm->num_idle_slots) > 0));
+	}
+
+	idle_slot = list_first_entry(&ksm->idle_slots, struct keyslot,
+					     idle_slot_node);
+	slot = idle_slot - ksm->slots;
+
+	err = ksm->ksm_ll_ops.keyslot_program(ksm->ll_priv_data, key,
+					      crypt_mode,
+					      data_unit_size,
+					      slot);
+
+	if (err) {
+		wake_up(&ksm->idle_slots_wait_queue);
+		up_write(&ksm->lock);
+		return err;
+	}
+
+	atomic_inc(&ksm->slots[slot].slot_refs);
+	spin_lock_irqsave(&ksm->idle_slots_lock, flags);
+	list_del(&idle_slot->idle_slot_node);
+	spin_unlock_irqrestore(&ksm->idle_slots_lock, flags);
+	atomic_dec(&ksm->num_idle_slots);
+
+	up_write(&ksm->lock);
+	return slot;
+
+}
+EXPORT_SYMBOL(keyslot_manager_get_slot_for_key);
+
+/**
+ * keyslot_manager_get_slot() - Increment the refcount on the specified slot.
+ * @ksm - The keyslot manager that we want to modify.
+ * @slot - The slot to increment the refcount of.
+ *
+ * This function assumes that there is already an active reference to that slot
+ * and simply increments the refcount. This is useful when cloning a bio that
+ * already has a reference to a keyslot, and we want the cloned bio to also have
+ * its own reference.
+ *
+ * Context: Any context.
+ */
+void keyslot_manager_get_slot(struct keyslot_manager *ksm, unsigned int slot)
+{
+	if (WARN_ON(slot >= ksm->num_slots))
+		return;
+
+	WARN_ON(atomic_inc_return(&ksm->slots[slot].slot_refs) < 2);
+}
+EXPORT_SYMBOL(keyslot_manager_get_slot);
+
+/**
+ * keyslot_manager_put_slot() - Release a reference to a slot
+ * @ksm: The keyslot manager to release the reference from.
+ * @slot: The slot to release the reference from.
+ *
+ * Context: Any context.
+ */
+void keyslot_manager_put_slot(struct keyslot_manager *ksm, unsigned int slot)
+{
+	unsigned long flags;
+
+	if (WARN_ON(slot >= ksm->num_slots))
+		return;
+
+	spin_lock_irqsave(&ksm->idle_slots_lock, flags);
+	if (atomic_dec_and_test(&ksm->slots[slot].slot_refs)) {
+		list_add_tail(&ksm->slots[slot].idle_slot_node,
+			      &ksm->idle_slots);
+		spin_unlock_irqrestore(&ksm->idle_slots_lock, flags);
+		atomic_inc(&ksm->num_idle_slots);
+		wake_up(&ksm->idle_slots_wait_queue);
+	} else {
+		spin_unlock_irqrestore(&ksm->idle_slots_lock, flags);
+	}
+}
+EXPORT_SYMBOL(keyslot_manager_put_slot);
+
+/**
+ * keyslot_manager_evict_key() - Evict a key from the lower layer device.
+ * @ksm - The keyslot manager to evict from
+ * @key - The key to evict
+ * @crypt_mode - The crypto algorithm the key was programmed with.
+ * @data_unit_size - The data_unit_size the key was programmed with.
+ *
+ * Finds the slot that the specified key, crypt_mode, data_unit_size combo
+ * was programmed into, and evicts that slot from the lower layer device if
+ * the refcount on the slot is 0. Returns -EBUSY if the refcount is not 0, and
+ * -errno on error.
+ *
+ * Context: Process context. Takes and releases ksm->lock.
+ */
+int keyslot_manager_evict_key(struct keyslot_manager *ksm,
+			      const u8 *key,
+			      enum blk_crypt_mode_num crypt_mode,
+			      unsigned int data_unit_size)
+{
+	int slot;
+	int err = 0;
+
+	down_write(&ksm->lock);
+	slot = ksm->ksm_ll_ops.keyslot_find(ksm->ll_priv_data, key,
+					    crypt_mode,
+					    data_unit_size);
+
+	if (slot < 0) {
+		up_write(&ksm->lock);
+		return slot;
+	}
+
+	if (atomic_read(&ksm->slots[slot].slot_refs) == 0) {
+		err = ksm->ksm_ll_ops.keyslot_evict(ksm->ll_priv_data, key,
+						    crypt_mode,
+						    data_unit_size,
+						    slot);
+	} else {
+		err = -EBUSY;
+	}
+
+	up_write(&ksm->lock);
+	return err;
+}
+EXPORT_SYMBOL(keyslot_manager_evict_key);
+
+void keyslot_manager_destroy(struct keyslot_manager *ksm)
+{
+	if (!ksm)
+		return;
+	kvfree(ksm);
+}
+EXPORT_SYMBOL(keyslot_manager_destroy);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index f87abaa898f0..ef9c6e2e92bc 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -561,6 +561,17 @@ static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 }
 #endif
 
+enum blk_crypt_mode_num {
+	BLK_ENCRYPTION_MODE_AES_256_XTS	= 0,
+	/*
+	 * TODO: Support these too
+	 * BLK_ENCRYPTION_MODE_AES_256_CTS	= 1,
+	 * BLK_ENCRYPTION_MODE_AES_128_CBC	= 2,
+	 * BLK_ENCRYPTION_MODE_AES_128_CTS	= 3,
+	 * BLK_ENCRYPTION_MODE_ADIANTUM		= 4,
+	 */
+};
+
 /*
  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
  *
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 592669bcc536..3bb4e7e1bd78 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -43,6 +43,7 @@ struct pr_ops;
 struct rq_qos;
 struct blk_queue_stats;
 struct blk_stat_callback;
+struct keyslot_manager;
 
 #define BLKDEV_MIN_RQ	4
 #define BLKDEV_MAX_RQ	128	/* Default maximum */
@@ -473,6 +474,11 @@ struct request_queue {
 	unsigned int		dma_pad_mask;
 	unsigned int		dma_alignment;
 
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+	/* Inline crypto capabilities */
+	struct keyslot_manager *ksm;
+#endif
+
 	unsigned int		rq_timeout;
 	int			poll_nsec;
 
diff --git a/include/linux/keyslot-manager.h b/include/linux/keyslot-manager.h
new file mode 100644
index 000000000000..ee97692997c8
--- /dev/null
+++ b/include/linux/keyslot-manager.h
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#include <linux/bio.h>
+
+#ifndef __LINUX_KEYSLOT_MANAGER_H
+#define __LINUX_KEYSLOT_MANAGER_H
+
+/**
+ * struct keyslot_mgmt_ll_ops - functions to manage keyslots in hardware
+ * @keyslot_program:	Program the specified key and algorithm into the
+ *			specified slot in the inline encryption hardware.
+ * @keyslot_evict:	Evict key from the specified keyslot in the hardware.
+ *			The key, crypt_mode and data_unit_size are also passed
+ *			down so that for e.g. dm layers can evict keys from
+ *			the devices that they map over.
+ *			Returns 0 on success, -errno otherwise.
+ * @crypt_mode_supported:	Check whether a crypt_mode and data_unit_size
+ *				combo is supported.
+ * @keyslot_find:	Returns the slot number that matches the key,
+ *			or -ENOKEY if no match found, or -errno on
+ *			error.
+ *
+ * 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)(void *ll_priv_data, const u8 *key,
+			       enum blk_crypt_mode_num crypt_mode,
+			       unsigned int data_unit_size,
+			       unsigned int slot);
+	int (*keyslot_evict)(void *ll_priv_data, const u8 *key,
+			     enum blk_crypt_mode_num crypt_mode,
+			     unsigned int data_unit_size,
+			     unsigned int slot);
+	bool (*crypt_mode_supported)(void *ll_priv_data,
+				      enum blk_crypt_mode_num crypt_mode,
+				      unsigned int data_unit_size);
+	int (*keyslot_find)(void *ll_priv_data, const u8 *key,
+			    enum blk_crypt_mode_num crypt_mode,
+			    unsigned int data_unit_size);
+};
+
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+struct keyslot_manager;
+
+extern struct keyslot_manager *keyslot_manager_create(unsigned int num_slots,
+				const struct keyslot_mgmt_ll_ops *ksm_ops,
+				void *ll_priv_data);
+
+extern int
+keyslot_manager_get_slot_for_key(struct keyslot_manager *ksm,
+				 const u8 *key,
+				 enum blk_crypt_mode_num crypt_mode,
+				 unsigned int data_unit_size);
+
+extern void keyslot_manager_get_slot(struct keyslot_manager *ksm,
+				     unsigned int slot);
+
+extern void keyslot_manager_put_slot(struct keyslot_manager *ksm,
+				     unsigned int slot);
+
+extern int keyslot_manager_evict_key(struct keyslot_manager *ksm,
+				     const u8 *key,
+				     enum blk_crypt_mode_num crypt_mode,
+				     unsigned int data_unit_size);
+
+extern void keyslot_manager_destroy(struct keyslot_manager *ksm);
+
+#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
+
+#endif /* __LINUX_KEYSLOT_MANAGER_H */
-- 
2.22.0.410.gd8fdbe21b5-goog



_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

[f2fs-dev] [PATCH 2/8] block: Add encryption context to struct bio

[Satya Tangirala via Linux-f2fs-devel]

We must have some way of letting a storage device driver know what
encryption context it should use for en/decrypting a request. However,
it's the filesystem/fscrypt that knows about and manages encryption
contexts. As such, when the filesystem layer submits a bio to the block
layer, and this bio eventually reaches a device driver with support for
inline encryption, the device driver will need to have been told the
encryption context for that bio.

We want to communicate the encryption context from the filesystem layer
to the storage device along with the bio, when the bio is submitted to the
block layer. To do this, we add a struct bio_crypt_ctx to struct bio, which
can represent an encryption context (note that we can't use the bi_private
field in struct bio to do this because that field does not function to pass
information across layers in the storage stack). We also introduce various
functions to manipulate the bio_crypt_ctx and make the bio/request merging
logic aware of the bio_crypt_ctx.

Signed-off-by: Satya Tangirala <satyat@google.com>
---
 block/Makefile            |   2 +-
 block/bio-crypt-ctx.c     | 117 +++++++++++++++++++++++
 block/bio.c               |  11 ++-
 block/blk-merge.c         |  34 ++++++-
 block/bounce.c            |   9 +-
 drivers/md/dm.c           |  15 ++-
 include/linux/bio.h       | 190 ++++++++++++++++++++++++++++++++++++++
 include/linux/blk_types.h |   7 ++
 8 files changed, 371 insertions(+), 14 deletions(-)
 create mode 100644 block/bio-crypt-ctx.c

diff --git a/block/Makefile b/block/Makefile
index a72abd61b220..4147ffa63631 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -35,4 +35,4 @@ obj-$(CONFIG_BLK_DEBUG_FS)	+= blk-mq-debugfs.o
 obj-$(CONFIG_BLK_DEBUG_FS_ZONED)+= blk-mq-debugfs-zoned.o
 obj-$(CONFIG_BLK_SED_OPAL)	+= sed-opal.o
 obj-$(CONFIG_BLK_PM)		+= blk-pm.o
-obj-$(CONFIG_BLK_INLINE_ENCRYPTION)	+= keyslot-manager.o
+obj-$(CONFIG_BLK_INLINE_ENCRYPTION)	+= keyslot-manager.o bio-crypt-ctx.o
diff --git a/block/bio-crypt-ctx.c b/block/bio-crypt-ctx.c
new file mode 100644
index 000000000000..8b884ef32007
--- /dev/null
+++ b/block/bio-crypt-ctx.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+#include <linux/keyslot-manager.h>
+
+struct bio_crypt_ctx *bio_crypt_alloc_ctx(gfp_t gfp_mask)
+{
+	return kzalloc(sizeof(struct bio_crypt_ctx), gfp_mask);
+}
+EXPORT_SYMBOL(bio_crypt_alloc_ctx);
+
+void bio_crypt_free_ctx(struct bio *bio)
+{
+	kzfree(bio->bi_crypt_context);
+	bio->bi_crypt_context = NULL;
+}
+EXPORT_SYMBOL(bio_crypt_free_ctx);
+
+int bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask)
+{
+	if (!bio_is_encrypted(src))
+		return 0;
+
+	dst->bi_crypt_context = bio_crypt_alloc_ctx(gfp_mask);
+	if (!dst->bi_crypt_context)
+		return -ENOMEM;
+
+	*dst->bi_crypt_context = *src->bi_crypt_context;
+
+	if (bio_crypt_has_keyslot(src))
+		keyslot_manager_get_slot(src->bi_crypt_context->processing_ksm,
+					 src->bi_crypt_context->keyslot);
+
+	return 0;
+}
+EXPORT_SYMBOL(bio_crypt_clone);
+
+bool bio_crypt_should_process(struct bio *bio, struct request_queue *q)
+{
+	if (!bio_is_encrypted(bio))
+		return false;
+
+	WARN_ON(!bio_crypt_has_keyslot(bio));
+	return q->ksm == bio->bi_crypt_context->processing_ksm;
+}
+EXPORT_SYMBOL(bio_crypt_should_process);
+
+/*
+ * Checks that two bio crypt contexts are compatible - i.e. that
+ * they are mergeable except for data_unit_num continuity.
+ */
+bool bio_crypt_ctx_compatible(struct bio *b_1, struct bio *b_2)
+{
+	struct bio_crypt_ctx *bc1 = b_1->bi_crypt_context;
+	struct bio_crypt_ctx *bc2 = b_2->bi_crypt_context;
+
+	if (bio_is_encrypted(b_1) != bio_is_encrypted(b_2))
+		return false;
+
+	if (!bio_is_encrypted(b_1))
+		return true;
+
+	return bc1->keyslot == bc2->keyslot &&
+	       bc1->data_unit_size_bits == bc2->data_unit_size_bits;
+}
+
+/*
+ * Checks that two bio crypt contexts are compatible, and also
+ * that their data_unit_nums are continuous (and can hence be merged)
+ */
+bool bio_crypt_ctx_back_mergeable(struct bio *b_1,
+				  unsigned int b1_sectors,
+				  struct bio *b_2)
+{
+	struct bio_crypt_ctx *bc1 = b_1->bi_crypt_context;
+	struct bio_crypt_ctx *bc2 = b_2->bi_crypt_context;
+
+	if (!bio_crypt_ctx_compatible(b_1, b_2))
+		return false;
+
+	return !bio_is_encrypted(b_1) ||
+		(bc1->data_unit_num +
+		(b1_sectors >> (bc1->data_unit_size_bits - 9)) ==
+		bc2->data_unit_num);
+}
+
+void bio_crypt_ctx_release_keyslot(struct bio *bio)
+{
+	struct bio_crypt_ctx *crypt_ctx = bio->bi_crypt_context;
+
+	keyslot_manager_put_slot(crypt_ctx->processing_ksm, crypt_ctx->keyslot);
+	bio->bi_crypt_context->processing_ksm = NULL;
+	bio->bi_crypt_context->keyslot = -1;
+}
+
+int bio_crypt_ctx_acquire_keyslot(struct bio *bio, struct keyslot_manager *ksm)
+{
+	int slot;
+	enum blk_crypt_mode_num crypt_mode = bio_crypt_mode(bio);
+
+	if (!ksm)
+		return -ENOMEM;
+
+	slot = keyslot_manager_get_slot_for_key(ksm,
+			bio_crypt_raw_key(bio), crypt_mode,
+			1 << bio->bi_crypt_context->data_unit_size_bits);
+	if (slot < 0)
+		return slot;
+
+	bio_crypt_set_keyslot(bio, slot, ksm);
+	return 0;
+}
diff --git a/block/bio.c b/block/bio.c
index ce797d73bb43..2a272cda6dfa 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -240,6 +240,7 @@ static void bio_free(struct bio *bio)
 	struct bio_set *bs = bio->bi_pool;
 	void *p;
 
+	bio_crypt_free_ctx(bio);
 	bio_uninit(bio);
 
 	if (bs) {
@@ -612,6 +613,7 @@ EXPORT_SYMBOL(__bio_clone_fast);
 struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
 {
 	struct bio *b;
+	int ret;
 
 	b = bio_alloc_bioset(gfp_mask, 0, bs);
 	if (!b)
@@ -619,9 +621,13 @@ struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs)
 
 	__bio_clone_fast(b, bio);
 
-	if (bio_integrity(bio)) {
-		int ret;
+	ret = bio_crypt_clone(b, bio, gfp_mask);
+	if (ret < 0) {
+		bio_put(b);
+		return NULL;
+	}
 
+	if (bio_integrity(bio)) {
 		ret = bio_integrity_clone(b, bio, gfp_mask);
 
 		if (ret < 0) {
@@ -1022,6 +1028,7 @@ void bio_advance(struct bio *bio, unsigned bytes)
 	if (bio_integrity(bio))
 		bio_integrity_advance(bio, bytes);
 
+	bio_crypt_advance(bio, bytes);
 	bio_advance_iter(bio, &bio->bi_iter, bytes);
 }
 EXPORT_SYMBOL(bio_advance);
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 17713d7d98d5..f416e7f38270 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -531,6 +531,9 @@ static inline int ll_new_hw_segment(struct request_queue *q,
 	if (blk_integrity_merge_bio(q, req, bio) == false)
 		goto no_merge;
 
+	if (WARN_ON(!bio_crypt_ctx_compatible(bio, req->bio)))
+		goto no_merge;
+
 	/*
 	 * This will form the start of a new hw segment.  Bump both
 	 * counters.
@@ -696,8 +699,13 @@ static enum elv_merge blk_try_req_merge(struct request *req,
 {
 	if (blk_discard_mergable(req))
 		return ELEVATOR_DISCARD_MERGE;
-	else if (blk_rq_pos(req) + blk_rq_sectors(req) == blk_rq_pos(next))
+	else if (blk_rq_pos(req) + blk_rq_sectors(req) == blk_rq_pos(next)) {
+		if (!bio_crypt_ctx_back_mergeable(
+			req->bio, blk_rq_sectors(req), next->bio)) {
+			return ELEVATOR_NO_MERGE;
+		}
 		return ELEVATOR_BACK_MERGE;
+	}
 
 	return ELEVATOR_NO_MERGE;
 }
@@ -733,6 +741,9 @@ static struct request *attempt_merge(struct request_queue *q,
 	if (req->ioprio != next->ioprio)
 		return NULL;
 
+	if (!bio_crypt_ctx_compatible(req->bio, next->bio))
+		return NULL;
+
 	/*
 	 * If we are allowed to merge, then append bio list
 	 * from next to rq and release next. merge_requests_fn
@@ -865,16 +876,31 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
 	if (rq->ioprio != bio_prio(bio))
 		return false;
 
+	/* Only merge if the crypt contexts are compatible */
+	if (!bio_crypt_ctx_compatible(bio, rq->bio))
+		return false;
+
 	return true;
 }
 
 enum elv_merge blk_try_merge(struct request *rq, struct bio *bio)
 {
-	if (blk_discard_mergable(rq))
+	if (blk_discard_mergable(rq)) {
 		return ELEVATOR_DISCARD_MERGE;
-	else if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_iter.bi_sector)
+	} else if (blk_rq_pos(rq) + blk_rq_sectors(rq) ==
+		   bio->bi_iter.bi_sector) {
+		if (!bio_crypt_ctx_back_mergeable(rq->bio,
+						  blk_rq_sectors(rq), bio)) {
+			return ELEVATOR_NO_MERGE;
+		}
 		return ELEVATOR_BACK_MERGE;
-	else if (blk_rq_pos(rq) - bio_sectors(bio) == bio->bi_iter.bi_sector)
+	} else if (blk_rq_pos(rq) - bio_sectors(bio) ==
+		   bio->bi_iter.bi_sector) {
+		if (!bio_crypt_ctx_back_mergeable(bio,
+						  bio_sectors(bio), rq->bio)) {
+			return ELEVATOR_NO_MERGE;
+		}
 		return ELEVATOR_FRONT_MERGE;
+	}
 	return ELEVATOR_NO_MERGE;
 }
diff --git a/block/bounce.c b/block/bounce.c
index f8ed677a1bf7..1307238d3951 100644
--- a/block/bounce.c
+++ b/block/bounce.c
@@ -220,6 +220,7 @@ static struct bio *bounce_clone_bio(struct bio *bio_src, gfp_t gfp_mask,
 	struct bvec_iter iter;
 	struct bio_vec bv;
 	struct bio *bio;
+	int ret;
 
 	/*
 	 * Pre immutable biovecs, __bio_clone() used to just do a memcpy from
@@ -267,9 +268,13 @@ static struct bio *bounce_clone_bio(struct bio *bio_src, gfp_t gfp_mask,
 		break;
 	}
 
-	if (bio_integrity(bio_src)) {
-		int ret;
+	ret = bio_crypt_clone(bio, bio_src, gfp_mask);
+	if (ret < 0) {
+		bio_put(bio);
+		return NULL;
+	}
 
+	if (bio_integrity(bio_src)) {
 		ret = bio_integrity_clone(bio, bio_src, gfp_mask);
 		if (ret < 0) {
 			bio_put(bio);
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 5475081dcbd6..22517d03aa39 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1324,12 +1324,15 @@ static int clone_bio(struct dm_target_io *tio, struct bio *bio,
 		     sector_t sector, unsigned len)
 {
 	struct bio *clone = &tio->clone;
+	int ret;
 
 	__bio_clone_fast(clone, bio);
 
-	if (bio_integrity(bio)) {
-		int r;
+	ret = bio_crypt_clone(clone, bio, GFP_NOIO);
+	if (ret < 0)
+		return ret;
 
+	if (bio_integrity(bio)) {
 		if (unlikely(!dm_target_has_integrity(tio->ti->type) &&
 			     !dm_target_passes_integrity(tio->ti->type))) {
 			DMWARN("%s: the target %s doesn't support integrity data.",
@@ -1338,9 +1341,11 @@ static int clone_bio(struct dm_target_io *tio, struct bio *bio,
 			return -EIO;
 		}
 
-		r = bio_integrity_clone(clone, bio, GFP_NOIO);
-		if (r < 0)
-			return r;
+		ret = bio_integrity_clone(clone, bio, GFP_NOIO);
+		if (ret < 0) {
+			bio_crypt_free_ctx(clone);
+			return ret;
+		}
 	}
 
 	bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector));
diff --git a/include/linux/bio.h b/include/linux/bio.h
index ef9c6e2e92bc..4e664d6441d5 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -572,6 +572,196 @@ enum blk_crypt_mode_num {
 	 */
 };
 
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+struct bio_crypt_ctx {
+	int keyslot;
+	u8 *raw_key;
+	enum blk_crypt_mode_num crypt_mode;
+	u64 data_unit_num;
+	unsigned int data_unit_size_bits;
+
+	/*
+	 * The keyslot manager where the key has been programmed
+	 * with keyslot.
+	 */
+	struct keyslot_manager *processing_ksm;
+
+	/*
+	 * Copy of the bvec_iter when this bio was submitted.
+	 * We only want to en/decrypt the part of the bio
+	 * as described by the bvec_iter upon submission because
+	 * bio might be split before being resubmitted
+	 */
+	struct bvec_iter crypt_iter;
+	u64 sw_data_unit_num;
+};
+
+extern int bio_crypt_clone(struct bio *dst, struct bio *src,
+			   gfp_t gfp_mask);
+
+static inline bool bio_is_encrypted(struct bio *bio)
+{
+	return bio->bi_crypt_context;
+}
+
+static inline void bio_crypt_advance(struct bio *bio, unsigned int bytes)
+{
+	if (bio_is_encrypted(bio)) {
+		bio->bi_crypt_context->data_unit_num +=
+			bytes >> bio->bi_crypt_context->data_unit_size_bits;
+	}
+}
+
+static inline bool bio_crypt_has_keyslot(struct bio *bio)
+{
+	return bio->bi_crypt_context->keyslot >= 0;
+}
+
+extern struct bio_crypt_ctx *bio_crypt_alloc_ctx(gfp_t gfp_mask);
+
+extern void bio_crypt_free_ctx(struct bio *bio);
+
+static inline int bio_crypt_set_ctx(struct bio *bio,
+				    u8 *raw_key,
+				    enum blk_crypt_mode_num crypt_mode,
+				    u64 dun,
+				    unsigned int dun_bits)
+{
+	struct bio_crypt_ctx *crypt_ctx;
+
+	crypt_ctx = bio_crypt_alloc_ctx(GFP_NOIO);
+	if (!crypt_ctx)
+		return -ENOMEM;
+
+	crypt_ctx->raw_key = raw_key;
+	crypt_ctx->data_unit_num = dun;
+	crypt_ctx->data_unit_size_bits = dun_bits;
+	crypt_ctx->crypt_mode = crypt_mode;
+	crypt_ctx->processing_ksm = NULL;
+	crypt_ctx->keyslot = -1;
+	bio->bi_crypt_context = crypt_ctx;
+
+	return 0;
+}
+
+static inline int bio_crypt_get_keyslot(struct bio *bio)
+{
+	return bio->bi_crypt_context->keyslot;
+}
+
+static inline void bio_crypt_set_keyslot(struct bio *bio,
+					 unsigned int keyslot,
+					 struct keyslot_manager *ksm)
+{
+	bio->bi_crypt_context->keyslot = keyslot;
+	bio->bi_crypt_context->processing_ksm = ksm;
+}
+
+extern void bio_crypt_ctx_release_keyslot(struct bio *bio);
+
+extern int bio_crypt_ctx_acquire_keyslot(struct bio *bio,
+					 struct keyslot_manager *ksm);
+
+static inline u8 *bio_crypt_raw_key(struct bio *bio)
+{
+	return bio->bi_crypt_context->raw_key;
+}
+
+static inline enum blk_crypt_mode_num bio_crypt_mode(struct bio *bio)
+{
+	return bio->bi_crypt_context->crypt_mode;
+}
+
+static inline u64 bio_crypt_data_unit_num(struct bio *bio)
+{
+	WARN_ON(!bio_is_encrypted(bio));
+	return bio->bi_crypt_context->data_unit_num;
+}
+
+static inline u64 bio_crypt_sw_data_unit_num(struct bio *bio)
+{
+	WARN_ON(!bio_is_encrypted(bio));
+	return bio->bi_crypt_context->sw_data_unit_num;
+}
+
+extern bool bio_crypt_should_process(struct bio *bio, struct request_queue *q);
+
+extern bool bio_crypt_ctx_compatible(struct bio *b_1, struct bio *b_2);
+
+extern bool bio_crypt_ctx_back_mergeable(struct bio *b_1,
+					 unsigned int b1_sectors,
+					 struct bio *b_2);
+
+#else /* CONFIG_BLK_INLINE_ENCRYPTION */
+struct keyslot_manager;
+
+static inline int bio_crypt_clone(struct bio *dst, struct bio *src,
+				  gfp_t gfp_mask)
+{
+	return 0;
+}
+
+static inline void bio_crypt_advance(struct bio *bio,
+				     unsigned int bytes) { }
+
+static inline bool bio_is_encrypted(struct bio *bio)
+{
+	return false;
+}
+
+static inline void bio_crypt_free_ctx(struct bio *bio) { }
+
+static inline void bio_crypt_set_ctx(struct bio *bio,
+				     u8 *raw_key,
+				     enum blk_crypt_mode_num crypt_mode,
+				     u64 dun,
+				     unsigned int dun_bits) { }
+
+static inline bool bio_crypt_has_keyslot(struct bio *bio)
+{
+	return false;
+}
+
+static inline void bio_crypt_set_keyslot(struct bio *bio,
+					 unsigned int keyslot,
+					 struct keyslot_manager *ksm) { }
+
+static inline int bio_crypt_get_keyslot(struct bio *bio)
+{
+	return -1;
+}
+
+static inline u8 *bio_crypt_raw_key(struct bio *bio)
+{
+	return NULL;
+}
+
+static inline u64 bio_crypt_data_unit_num(struct bio *bio)
+{
+	WARN_ON(1);
+	return 0;
+}
+
+static inline bool bio_crypt_should_process(struct bio *bio,
+					    struct request_queue *q)
+{
+	return false;
+}
+
+static inline bool bio_crypt_ctx_compatible(struct bio *b_1, struct bio *b_2)
+{
+	return true;
+}
+
+static inline bool bio_crypt_ctx_back_mergeable(struct bio *b_1,
+						unsigned int b1_sectors,
+						struct bio *b_2)
+{
+	return true;
+}
+
+#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
+
 /*
  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
  *
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 95202f80676c..0b794fe3530a 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -137,6 +137,8 @@ static inline void bio_issue_init(struct bio_issue *issue,
 			((u64)size << BIO_ISSUE_SIZE_SHIFT));
 }
 
+struct bio_crypt_ctx;
+
 /*
  * main unit of I/O for the block layer and lower layers (ie drivers and
  * stacking drivers)
@@ -175,6 +177,11 @@ struct bio {
 	struct blkcg_gq		*bi_blkg;
 	struct bio_issue	bi_issue;
 #endif
+
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+	struct bio_crypt_ctx	*bi_crypt_context;
+#endif
+
 	union {
 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 		struct bio_integrity_payload *bi_integrity; /* data integrity */
-- 
2.22.0.410.gd8fdbe21b5-goog



_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

[f2fs-dev] [PATCH 3/8] block: blk-crypto for Inline Encryption

[Satya Tangirala via Linux-f2fs-devel]

We introduce blk-crypto, which manages programming keyslots for struct
bios. With blk-crypto, filesystems only need to call bio_crypt_set_ctx with
the encryption key, algorithm and data_unit_num; they don't have to worry
about getting a keyslot for each encryption context, as blk-crypto handles
that. Blk-crypto also makes it possible for layered devices like device
mapper to make use of inline encryption hardware.

Blk-crypto delegates crypto operations to inline encryption hardware when
available, and also contains a software fallback to the kernel crypto API.
For more details, refer to Documentation/block/blk-crypto.txt.

Known issues:
1) We're allocating crypto_skcipher in blk_crypto_keyslot_program, which
uses GFP_KERNEL to allocate memory, but this function is on the write
path for IO - we need to add support for specifying a different flags
to the crypto API.

Signed-off-by: Satya Tangirala <satyat@google.com>
---
 Documentation/block/inline-encryption.txt | 185 +++++++
 block/Makefile                            |   3 +-
 block/bio-crypt-ctx.c                     |   7 +-
 block/bio.c                               |   5 +
 block/blk-core.c                          |  11 +-
 block/blk-crypto.c                        | 585 ++++++++++++++++++++++
 include/linux/bio.h                       |   7 +
 include/linux/blk-crypto.h                |  40 ++
 8 files changed, 840 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/block/inline-encryption.txt
 create mode 100644 block/blk-crypto.c
 create mode 100644 include/linux/blk-crypto.h

diff --git a/Documentation/block/inline-encryption.txt b/Documentation/block/inline-encryption.txt
new file mode 100644
index 000000000000..96a7983a117d
--- /dev/null
+++ b/Documentation/block/inline-encryption.txt
@@ -0,0 +1,185 @@
+BLK-CRYPTO and KEYSLOT MANAGER
+===========================
+
+CONTENTS
+1. Objective
+2. Constraints and notes
+3. Design
+4. Blk-crypto
+ 4-1 What does blk-crypto do on bio submission
+5. Layered Devices
+6. Future optimizations for layered devices
+
+1. Objective
+============
+
+We want to support inline encryption (IE) in the kernel.
+To allow for testing, we also want a software fallback when actual
+IE hardware is absent. We also want IE to work with layered devices
+like dm and loopback (i.e. we want to be able to use the IE hardware
+of the underlying devices if present, or else fall back to software
+en/decryption).
+
+
+2. Constraints and notes
+========================
+
+1) IE hardware have a limited number of “keyslots” that can be programmed
+with an encryption context (key, algorithm, data unit size, etc.) at any time.
+One can specify a keyslot in a data request made to the device, and the
+device will en/decrypt the data using the encryption context programmed into
+that specified keyslot. When possible, we want to make multiple requests with
+the same encryption context share the same keyslot.
+
+2) We need a way for filesystems to specify an encryption context to use for
+en/decrypting a struct bio, and a device driver (like UFS) needs to be able
+to use that encryption context when it processes the bio.
+
+3) We need a way for device drivers to expose their capabilities in a unified
+way to the upper layers.
+
+
+3. Design
+=========
+
+We add a struct bio_crypt_context to struct bio that can represent an
+encryption context, because we need to able to pass this encryption context
+from the FS layer to the device driver to act upon.
+
+While IE hardware works on the notion of keyslots, the FS layer has no
+knowledge of keyslots - it simply wants to specify an encryption context to
+use while en/decrypting a bio.
+
+We introduce a keyslot manager (KSM) that handles the translation from
+encryption contexts specified by the FS to keyslots on the IE hardware.
+This KSM also serves as the way IE hardware can expose their capabilities to
+upper layers. The generic mode of operation is: each device driver that wants
+to support IE will construct a KSM and set it up in its struct request_queue.
+Upper layers that want to use IE on this device can then use this KSM in
+the device’s struct request_queue to translate an encryption context into
+a keyslot. The presence of the KSM in the request queue shall be used to mean
+that the device supports IE.
+
+On the device driver end of the interface, the device driver needs to tell the
+KSM how to actually manipulate the IE hardware in the device to do things like
+programming the crypto key into the IE hardware into a particular keyslot. All
+this is achieved through the struct keyslot_mgmt_ll_ops that the device driver
+passes to the KSM when creating it.
+
+It uses refcounts to track which keyslots are idle (either they have no
+encryption context programmed, or there are no in flight struct bios
+referencing that keyslot). When a new encryption context needs a keyslot, it
+tries to find a keyslot that has already been programmed with the same
+encryption context, and if there is no such keyslot, it evicts the least
+recently used idle keyslot and programs the new encryption context into that
+one. If no idle keyslots are available, then the caller will sleep until there
+is at least one.
+
+
+4. Blk-crypto
+=============
+
+The above is sufficient for simple cases, but does not work if there is a
+need for a software fallback, or if we are want to use IE with layered devices.
+To these ends, we introduce blk-crypto. Blk-crypto allows us to present a
+unified view of encryption to the FS (so FS only needs to specify an
+encryption context and not worry about keyslots at all), and blk-crypto can
+decide whether to delegate the en/decryption to IE hardware or to software
+(i.e. to the kernel crypto API). Blk-crypto maintains an internal KSM that
+serves as the software fallback to the kernel crypto API.
+
+Blk-crypto needs to ensure that the encryption context is programmed into the
+"correct" keyslot manager for IE. If a bio is submitted to a layered device
+that eventually passes the bio down to a device that really does support IE, we
+want the encryption context to be programmed into a keyslot for the KSM of the
+device with IE support. However, blk-crypto does not know a priori whether a
+particular device is the final device in the layering structure for a bio or
+not. So in the case that a particular device does not support IE, since it is
+possibly the final destination device for the bio, if the bio requires
+encryption (i.e. the bio is doing a write operation), blk-crypto must fallback
+to software *before* sending the bio to the device.
+
+Blk-crypto ensures that
+1) The bio’s encryption context is programmed into a keyslot in the KSM of the
+request queue that the bio is being submitted to (or the software fallback KSM
+if the request queue doesn’t have a KSM), and that the processing_ksm in the
+bi_crypt_context is set to this KSM
+
+2) That the bio has its own individual reference to the keyslot in this KSM.
+Once the bio passes through blk-crypto, its encryption context is programmed
+in some KSM. The “its own individual reference to the keyslot” ensures that
+keyslots can be released by each bio independently of other bios while ensuring
+that the bio has a valid reference to the keyslot when, for e.g., the software
+fallback KSM in blk-crypto performs crypto for on the device’s behalf. The
+individual references are ensured by increasing the refcount for the keyslot in
+the processing_ksm when a bio with a programmed encryption context is cloned.
+
+
+4-1. What blk-crypto does on bio submission
+-------------------------------------------
+
+Case 1: blk-crypto is given a bio with only an encryption context that hasn’t
+been programmed into any keyslot in any KSM (for e.g. a bio from the FS). In
+this case, blk-crypto will program the encryption context into the KSM of the
+request queue the bio is being submitted to (and if this KSM does not exist,
+then it will program it into blk-crypto’s internal KSM for software fallback).
+The KSM that this encryption context was programmed into is stored as the
+processing_ksm in the bio’s bi_crypt_context.
+
+Case 2: blk-crypto is given a bio whose encryption context has already been
+programmed into a keyslot in the *software fallback KSM*. In this case,
+blk-crypto does nothing; it treats the bio as not having specified an
+encryption context. Note that we cannot do what we will do in Case 3 here
+because we would have already encrypted the bio in software by this point.
+
+Case 3: blk-crypto is given a bio whose encryption context has already been
+programmed into a keyslot in some KSM (that is *not* the software fallback
+KSM). In this case, blk-crypto first releases that keyslot from that KSM and
+then treats the bio as in Case 1.
+
+This way, when a device driver is processing a bio, it can be sure that
+the bio’s encryption context has been programmed into some KSM (either the
+device driver’s request queue’s KSM, or blk-crypto’s software fallback KSM).
+It then simply needs to check if the bio’s processing_ksm is the device’s
+request queue’s KSM. If so, then it should proceed with IE. If not, it should
+simply do nothing with respect to crypto, because some other KSM (perhaps the
+blk-crypto software fallback KSM) is handling the en/decryption.
+
+Blk-crypto will release the keyslot that is being held by the bio (and also
+decrypt it if the bio is using the software fallback KSM) once
+bio_remaining_done returns true for the bio.
+
+
+5. Layered Devices
+==================
+
+Layered devices that wish to support IE need to create their own keyslot
+manager for their request queue, and expose whatever functionality they choose.
+When a layered device wants to pass a bio to another layer (either by
+resubmitting the same bio, or by submitting a clone), it doesn’t need to do
+anything special because the bio (or the clone) will once again pass through
+blk-crypto, which will work as described in Case 3. If a layered device wants
+for some reason to do the IO by itself instead of passing it on to a child
+device, but it also chose to expose IE capabilities by setting up a KSM in its
+request queue, it is then responsible for en/decrypting the data itself. In
+such cases, the device can choose to call the blk-crypto function
+blk_crypto_fallback_to_software (TODO: Not yet implemented), which will
+cause the en/decryption to be done via software fallback.
+
+
+6. Future Optimizations for layered devices
+===========================================
+
+Creating a keyslot manager for the layered device uses up memory for each
+keyslot, and in general, a layered device (like dm-linear) merely passes the
+request on to a “child” device, so the keyslots in the layered device itself
+might be completely unused. We can instead define a new type of KSM; the
+“passthrough KSM”, that layered devices can use to let blk-crypto know that
+this layered device *will* pass the bio to some child device (and hence
+through blk-crypto again, at which point blk-crypto can program the encryption
+context, instead of programming it into the layered device’s KSM). Again, if
+the device “lies” and decides to do the IO itself instead of passing it on to
+a child device, it is responsible for doing the en/decryption (and can choose
+to call blk_crypto_fallback_to_software). Another use case for the
+"passthrough KSM" is for IE devices that want to manage their own keyslots/do
+not have a limited number of keyslots.
diff --git a/block/Makefile b/block/Makefile
index 4147ffa63631..1ba7de84dbaf 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -35,4 +35,5 @@ obj-$(CONFIG_BLK_DEBUG_FS)	+= blk-mq-debugfs.o
 obj-$(CONFIG_BLK_DEBUG_FS_ZONED)+= blk-mq-debugfs-zoned.o
 obj-$(CONFIG_BLK_SED_OPAL)	+= sed-opal.o
 obj-$(CONFIG_BLK_PM)		+= blk-pm.o
-obj-$(CONFIG_BLK_INLINE_ENCRYPTION)	+= keyslot-manager.o bio-crypt-ctx.o
+obj-$(CONFIG_BLK_INLINE_ENCRYPTION)	+= keyslot-manager.o bio-crypt-ctx.o \
+					   blk-crypto.o
diff --git a/block/bio-crypt-ctx.c b/block/bio-crypt-ctx.c
index 8b884ef32007..91015645c4ea 100644
--- a/block/bio-crypt-ctx.c
+++ b/block/bio-crypt-ctx.c
@@ -23,7 +23,12 @@ EXPORT_SYMBOL(bio_crypt_free_ctx);
 
 int bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask)
 {
-	if (!bio_is_encrypted(src))
+	/*
+	 * If a bio is swhandled, then it will be decrypted when bio_endio
+	 * is called. As we only want the data to be decrypted once, copies
+	 * of the bio must not have have a crypt context.
+	 */
+	if (!bio_is_encrypted(src) || bio_crypt_swhandled(src))
 		return 0;
 
 	dst->bi_crypt_context = bio_crypt_alloc_ctx(gfp_mask);
diff --git a/block/bio.c b/block/bio.c
index 2a272cda6dfa..390777a76468 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -16,6 +16,7 @@
 #include <linux/workqueue.h>
 #include <linux/cgroup.h>
 #include <linux/blk-cgroup.h>
+#include <linux/blk-crypto.h>
 
 #include <trace/events/block.h>
 #include "blk.h"
@@ -1832,6 +1833,10 @@ void bio_endio(struct bio *bio)
 again:
 	if (!bio_remaining_done(bio))
 		return;
+
+	if (!blk_crypto_endio(bio))
+		return;
+
 	if (!bio_integrity_endio(bio))
 		return;
 
diff --git a/block/blk-core.c b/block/blk-core.c
index 8340f69670d8..aec4da8c27fa 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -36,6 +36,7 @@
 #include <linux/blk-cgroup.h>
 #include <linux/debugfs.h>
 #include <linux/bpf.h>
+#include <linux/blk-crypto.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/block.h>
@@ -1018,7 +1019,9 @@ blk_qc_t generic_make_request(struct bio *bio)
 			/* Create a fresh bio_list for all subordinate requests */
 			bio_list_on_stack[1] = bio_list_on_stack[0];
 			bio_list_init(&bio_list_on_stack[0]);
-			ret = q->make_request_fn(q, bio);
+
+			if (!blk_crypto_submit_bio(&bio))
+				ret = q->make_request_fn(q, bio);
 
 			blk_queue_exit(q);
 
@@ -1071,6 +1074,9 @@ blk_qc_t direct_make_request(struct bio *bio)
 	if (!generic_make_request_checks(bio))
 		return BLK_QC_T_NONE;
 
+	if (blk_crypto_submit_bio(&bio))
+		return BLK_QC_T_NONE;
+
 	if (unlikely(blk_queue_enter(q, nowait ? BLK_MQ_REQ_NOWAIT : 0))) {
 		if (nowait && !blk_queue_dying(q))
 			bio->bi_status = BLK_STS_AGAIN;
@@ -1750,5 +1756,8 @@ int __init blk_dev_init(void)
 	blk_debugfs_root = debugfs_create_dir("block", NULL);
 #endif
 
+	if (blk_crypto_init() < 0)
+		panic("Failed to init blk-crypto\n");
+
 	return 0;
 }
diff --git a/block/blk-crypto.c b/block/blk-crypto.c
new file mode 100644
index 000000000000..f41fb7819ae9
--- /dev/null
+++ b/block/blk-crypto.c
@@ -0,0 +1,585 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Google LLC
+ */
+#include <linux/blk-crypto.h>
+#include <linux/keyslot-manager.h>
+#include <linux/mempool.h>
+#include <linux/blk-cgroup.h>
+#include <crypto/skcipher.h>
+#include <crypto/algapi.h>
+#include <linux/module.h>
+
+struct blk_crypt_mode {
+	const char *cipher_str;
+	size_t keysize;
+};
+
+static const struct blk_crypt_mode blk_crypt_modes[] = {
+	[BLK_ENCRYPTION_MODE_AES_256_XTS] = {
+		.cipher_str = "xts(aes)",
+		.keysize = 64,
+	},
+};
+
+#define BLK_CRYPTO_MAX_KEY_SIZE 64
+/* TODO: Do we want to make this user configurable somehow? */
+static int blk_crypto_num_keyslots = 100;
+
+static struct blk_crypto_keyslot {
+	struct crypto_skcipher *tfm;
+	enum blk_crypt_mode_num crypt_mode;
+	u8 key[BLK_CRYPTO_MAX_KEY_SIZE];
+} *blk_crypto_keyslots;
+
+struct work_mem {
+	struct work_struct crypto_work;
+	struct bio *bio;
+};
+
+static struct keyslot_manager *blk_crypto_ksm;
+static struct workqueue_struct *blk_crypto_wq;
+static mempool_t *blk_crypto_page_pool;
+static struct kmem_cache *blk_crypto_work_mem_cache;
+
+static unsigned int num_prealloc_bounce_pg = 32;
+
+bool bio_crypt_swhandled(struct bio *bio)
+{
+	return bio_is_encrypted(bio) &&
+	       bio->bi_crypt_context->processing_ksm == blk_crypto_ksm;
+}
+
+static void evict_keyslot(unsigned int slot)
+{
+	struct blk_crypto_keyslot *slotp = &blk_crypto_keyslots[slot];
+
+	crypto_free_skcipher(slotp->tfm);
+	slotp->tfm = NULL;
+	memzero_explicit(slotp->key, BLK_CRYPTO_MAX_KEY_SIZE);
+}
+
+/* TODO: handle modes that need essiv */
+static int blk_crypto_keyslot_program(void *priv, const u8 *key,
+				      enum blk_crypt_mode_num crypt_mode,
+				      unsigned int data_unit_size,
+				      unsigned int slot)
+{
+	struct blk_crypto_keyslot *slotp = &blk_crypto_keyslots[slot];
+	struct crypto_skcipher *tfm = slotp->tfm;
+	const struct blk_crypt_mode *mode = &blk_crypt_modes[crypt_mode];
+	size_t keysize = mode->keysize;
+	int err;
+
+	if (crypt_mode != slotp->crypt_mode || !tfm) {
+		evict_keyslot(slot);
+		tfm = crypto_alloc_skcipher(
+			mode->cipher_str, 0, 0);
+		if (IS_ERR(tfm))
+			return PTR_ERR(tfm);
+
+		crypto_skcipher_set_flags(tfm,
+					  CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
+		slotp->crypt_mode = crypt_mode;
+		slotp->tfm = tfm;
+	}
+
+	err = crypto_skcipher_setkey(tfm, key, keysize);
+
+	if (err) {
+		evict_keyslot(slot);
+		return err;
+	}
+
+	memcpy(slotp->key, key, keysize);
+
+	return 0;
+}
+
+static int blk_crypto_keyslot_evict(void *priv, const u8 *key,
+				    enum blk_crypt_mode_num crypt_mode,
+				    unsigned int data_unit_size,
+				    unsigned int slot)
+{
+	evict_keyslot(slot);
+	return 0;
+}
+
+static int blk_crypto_keyslot_find(void *priv,
+				   const u8 *key,
+				   enum blk_crypt_mode_num crypt_mode,
+				   unsigned int data_unit_size_bytes)
+{
+	int slot;
+	const size_t keysize = blk_crypt_modes[crypt_mode].keysize;
+
+	/* TODO: hashmap? */
+	for (slot = 0; slot < blk_crypto_num_keyslots; slot++) {
+		if (blk_crypto_keyslots[slot].crypt_mode == crypt_mode &&
+		    !crypto_memneq(blk_crypto_keyslots[slot].key, key, keysize))
+			return slot;
+	}
+
+	return -ENOKEY;
+}
+
+static bool blk_crypt_mode_supported(void *priv,
+				     enum blk_crypt_mode_num crypt_mode,
+				     unsigned int data_unit_size)
+{
+	/* All blk_crypt_modes are required to have a software fallback. */
+	return true;
+}
+
+static const struct keyslot_mgmt_ll_ops blk_crypto_ksm_ll_ops = {
+	.keyslot_program	= blk_crypto_keyslot_program,
+	.keyslot_evict		= blk_crypto_keyslot_evict,
+	.keyslot_find		= blk_crypto_keyslot_find,
+	.crypt_mode_supported	= blk_crypt_mode_supported,
+};
+
+static void blk_crypto_encrypt_endio(struct bio *enc_bio)
+{
+	struct bio *src_bio = enc_bio->bi_private;
+	struct bio_vec *enc_bvec, *enc_bvec_end;
+
+	enc_bvec = enc_bio->bi_io_vec;
+	enc_bvec_end = enc_bvec + enc_bio->bi_vcnt;
+	for (; enc_bvec != enc_bvec_end; enc_bvec++)
+		mempool_free(enc_bvec->bv_page, blk_crypto_page_pool);
+
+	src_bio->bi_status = enc_bio->bi_status;
+
+	bio_put(enc_bio);
+	bio_endio(src_bio);
+}
+
+static struct bio *blk_crypto_clone_bio(struct bio *bio_src)
+{
+	struct bvec_iter iter;
+	struct bio_vec bv;
+	struct bio *bio;
+
+	bio = bio_alloc_bioset(GFP_NOIO, bio_segments(bio_src), NULL);
+	if (!bio)
+		return NULL;
+	bio->bi_disk		= bio_src->bi_disk;
+	bio->bi_opf		= bio_src->bi_opf;
+	bio->bi_ioprio		= bio_src->bi_ioprio;
+	bio->bi_write_hint	= bio_src->bi_write_hint;
+	bio->bi_iter.bi_sector	= bio_src->bi_iter.bi_sector;
+	bio->bi_iter.bi_size	= bio_src->bi_iter.bi_size;
+
+	bio_for_each_segment(bv, bio_src, iter)
+		bio->bi_io_vec[bio->bi_vcnt++] = bv;
+
+	if (bio_integrity(bio_src)) {
+		int ret;
+
+		ret = bio_integrity_clone(bio, bio_src, GFP_NOIO);
+		if (ret < 0) {
+			bio_put(bio);
+			return NULL;
+		}
+	}
+
+	bio_clone_blkg_association(bio, bio_src);
+	blkcg_bio_issue_init(bio);
+
+	return bio;
+}
+
+static int blk_crypto_encrypt_bio(struct bio **bio_ptr)
+{
+	struct bio *src_bio = *bio_ptr;
+	int slot;
+	struct skcipher_request *ciph_req = NULL;
+	DECLARE_CRYPTO_WAIT(wait);
+	struct bio_vec bv;
+	struct bvec_iter iter;
+	int err = 0;
+	u64 curr_dun;
+	union {
+		__le64 dun;
+		u8 bytes[16];
+	} iv;
+	struct scatterlist src, dst;
+	struct bio *enc_bio;
+	struct bio_vec *enc_bvec;
+	int i, j;
+	unsigned int num_sectors;
+	int data_unit_size;
+
+	/* Split the bio if it's too big for single page bvec */
+	i = 0;
+	num_sectors = 0;
+	data_unit_size = 1 << src_bio->bi_crypt_context->data_unit_size_bits;
+	bio_for_each_segment(bv, src_bio, iter) {
+		num_sectors += bv.bv_len >> 9;
+		if (bv.bv_len % data_unit_size != 0) {
+			src_bio->bi_status = BLK_STS_IOERR;
+			return -EIO;
+		}
+		if (++i == BIO_MAX_PAGES)
+			break;
+	}
+	if (num_sectors < bio_sectors(src_bio)) {
+		struct bio *split_bio;
+
+		split_bio = bio_split(src_bio, num_sectors, GFP_NOIO, NULL);
+		if (!split_bio) {
+			src_bio->bi_status = BLK_STS_RESOURCE;
+			return -ENOMEM;
+		}
+		bio_chain(split_bio, src_bio);
+		generic_make_request(src_bio);
+		*bio_ptr = split_bio;
+		src_bio = *bio_ptr;
+	}
+
+	enc_bio = blk_crypto_clone_bio(src_bio);
+	if (!enc_bio) {
+		src_bio->bi_status = BLK_STS_RESOURCE;
+		return -ENOMEM;
+	}
+
+	err = bio_crypt_ctx_acquire_keyslot(src_bio, blk_crypto_ksm);
+	if (err) {
+		src_bio->bi_status = BLK_STS_IOERR;
+		bio_put(enc_bio);
+		return err;
+	}
+	slot = bio_crypt_get_keyslot(src_bio);
+
+	ciph_req = skcipher_request_alloc(blk_crypto_keyslots[slot].tfm,
+					  GFP_NOIO);
+	if (!ciph_req) {
+		src_bio->bi_status = BLK_STS_RESOURCE;
+		err = -ENOMEM;
+		bio_put(enc_bio);
+		goto out_release_keyslot;
+	}
+
+	skcipher_request_set_callback(ciph_req,
+				      CRYPTO_TFM_REQ_MAY_BACKLOG |
+				      CRYPTO_TFM_REQ_MAY_SLEEP,
+				      crypto_req_done, &wait);
+
+	curr_dun = bio_crypt_data_unit_num(src_bio);
+	sg_init_table(&src, 1);
+	sg_init_table(&dst, 1);
+	for (i = 0, enc_bvec = enc_bio->bi_io_vec; i < enc_bio->bi_vcnt;
+	     enc_bvec++, i++) {
+		struct page *page = enc_bvec->bv_page;
+		struct page *ciphertext_page =
+			mempool_alloc(blk_crypto_page_pool, GFP_NOIO);
+
+		enc_bvec->bv_page = ciphertext_page;
+
+		if (!ciphertext_page)
+			goto no_mem_for_ciph_page;
+
+		for (j = 0; j < enc_bvec->bv_len / data_unit_size; j++) {
+			memset(&iv, 0, sizeof(iv));
+			iv.dun = cpu_to_le64(curr_dun);
+
+			sg_set_page(&src, page, data_unit_size,
+				    enc_bvec->bv_offset + j * data_unit_size);
+			sg_set_page(&dst, ciphertext_page, data_unit_size,
+				    enc_bvec->bv_offset + j * data_unit_size);
+
+			skcipher_request_set_crypt(ciph_req, &src, &dst,
+						   data_unit_size, iv.bytes);
+			err = crypto_wait_req(crypto_skcipher_encrypt(ciph_req),
+					      &wait);
+			if (err)
+				goto no_mem_for_ciph_page;
+			curr_dun++;
+		}
+		continue;
+no_mem_for_ciph_page:
+		err = -ENOMEM;
+		for (j = i - 1; j >= 0; j--) {
+			mempool_free(enc_bio->bi_io_vec[j].bv_page,
+				     blk_crypto_page_pool);
+		}
+		src_bio->bi_status = BLK_STS_RESOURCE;
+		bio_put(enc_bio);
+		goto out_release_cipher;
+	}
+
+	enc_bio->bi_private = src_bio;
+	enc_bio->bi_end_io = blk_crypto_encrypt_endio;
+
+	*bio_ptr = enc_bio;
+out_release_cipher:
+	skcipher_request_free(ciph_req);
+out_release_keyslot:
+	bio_crypt_ctx_release_keyslot(src_bio);
+	return err;
+}
+
+/*
+ * TODO: assumption right now is:
+ * each segment in bio has length divisible by the data_unit_size
+ */
+static void blk_crypto_decrypt_bio(struct work_struct *w)
+{
+	struct work_mem *work_mem =
+		container_of(w, struct work_mem, crypto_work);
+	struct bio *bio = work_mem->bio;
+	int slot;
+	struct skcipher_request *ciph_req;
+	DECLARE_CRYPTO_WAIT(wait);
+	struct bio_vec bv;
+	struct bvec_iter iter;
+	u64 curr_dun;
+	union {
+		__le64 dun;
+		u8 bytes[16];
+	} iv;
+	struct scatterlist sg;
+	int err;
+	int data_unit_size = 1 << bio->bi_crypt_context->data_unit_size_bits;
+	int i;
+
+	kmem_cache_free(blk_crypto_work_mem_cache, work_mem);
+
+	err = bio_crypt_ctx_acquire_keyslot(bio, blk_crypto_ksm);
+	if (err) {
+		bio->bi_status = BLK_STS_RESOURCE;
+		goto out_no_keyslot;
+	}
+
+	slot = bio_crypt_get_keyslot(bio);
+	ciph_req = skcipher_request_alloc(blk_crypto_keyslots[slot].tfm,
+					  GFP_NOIO);
+	if (!ciph_req) {
+		bio->bi_status = BLK_STS_RESOURCE;
+		goto out;
+	}
+
+	skcipher_request_set_callback(ciph_req,
+				      CRYPTO_TFM_REQ_MAY_BACKLOG |
+				      CRYPTO_TFM_REQ_MAY_SLEEP,
+				      crypto_req_done, &wait);
+
+	curr_dun = bio_crypt_sw_data_unit_num(bio);
+	sg_init_table(&sg, 1);
+	__bio_for_each_segment(bv, bio, iter,
+			       bio->bi_crypt_context->crypt_iter) {
+		if (bv.bv_len % data_unit_size != 0) {
+			bio->bi_status = BLK_STS_IOERR;
+			err = -EIO;
+			goto out;
+		}
+		for (i = 0; i < bv.bv_len / data_unit_size; i++) {
+			struct page *page = bv.bv_page;
+
+			memset(&iv, 0, sizeof(iv));
+			iv.dun = cpu_to_le64(curr_dun);
+
+			sg_set_page(&sg, page, data_unit_size,
+				    bv.bv_offset + i * data_unit_size);
+			skcipher_request_set_crypt(ciph_req, &sg, &sg,
+						   data_unit_size, iv.bytes);
+			err = crypto_wait_req(crypto_skcipher_decrypt(ciph_req),
+					      &wait);
+			if (err) {
+				bio->bi_status = BLK_STS_IOERR;
+				goto out;
+			}
+			curr_dun++;
+		}
+	}
+
+out:
+	skcipher_request_free(ciph_req);
+	bio_crypt_ctx_release_keyslot(bio);
+out_no_keyslot:
+	bio_endio(bio);
+}
+
+static void blk_crypto_queue_decrypt_bio(struct bio *bio)
+{
+	struct work_mem *work_mem =
+		kmem_cache_zalloc(blk_crypto_work_mem_cache, GFP_ATOMIC);
+
+	if (!work_mem) {
+		bio->bi_status = BLK_STS_RESOURCE;
+		return bio_endio(bio);
+	}
+
+	INIT_WORK(&work_mem->crypto_work, blk_crypto_decrypt_bio);
+	work_mem->bio = bio;
+	queue_work(blk_crypto_wq, &work_mem->crypto_work);
+}
+
+/**
+ * blk_crypto_submit_bio - handle submitting bio for inline encryption
+ *
+ * @bio_ptr: pointer to original bio pointer
+ *
+ * If the bio doesn't have inline encryption enabled or the submitter already
+ * specified a keyslot for the target device, do nothing.  Else, a raw key must
+ * have been provided, so acquire a device keyslot for it if supported.  Else,
+ * use the software crypto fallback.
+ *
+ * When the software fallback is used for encryption, blk-crypto may choose to
+ * split the bio into 2 - one that will continue to be processed and the other
+ * that will be resubmitted via generic_make_request. *bio_ptr will be updated
+ * to the first bio (the one that will continue to be processed).
+ *
+ * Return: 0 if bio submission should continue; nonzero if bio_endio() was
+ *        already called so bio submission should abort.
+ */
+int blk_crypto_submit_bio(struct bio **bio_ptr)
+{
+	struct bio *bio = *bio_ptr;
+	struct request_queue *q;
+	int err;
+	struct bio_crypt_ctx *crypt_ctx;
+
+	if (!bio_is_encrypted(bio) || !bio_has_data(bio))
+		return 0;
+
+	/*
+	 * When a read bio is marked for sw decryption, its bi_iter is saved
+	 * so that when we decrypt the bio later, we know what part of it was
+	 * marked for sw decryption (when the bio is passed down after
+	 * blk_crypto_submit bio, it may be split or advanced so we cannot rely
+	 * on the bi_iter while decrypting in blk_crypto_endio)
+	 */
+	if (bio_crypt_swhandled(bio))
+		return 0;
+
+	crypt_ctx = bio->bi_crypt_context;
+	q = bio->bi_disk->queue;
+
+	if (bio_crypt_has_keyslot(bio)) {
+		/* Key already programmed into device? */
+		if (q->ksm == crypt_ctx->processing_ksm)
+			return 0;
+
+		/* Nope, release the existing keyslot. */
+		bio_crypt_ctx_release_keyslot(bio);
+	}
+
+	/* Get device keyslot if supported */
+	if (q->ksm) {
+		err = bio_crypt_ctx_acquire_keyslot(bio, q->ksm);
+		if (!err) {
+			pr_warn_once("blk-crypto: failed to acquire keyslot for %s (err=%d).  Falling back to software crypto.\n",
+				     bio->bi_disk->disk_name, err);
+			return 0;
+		}
+	}
+
+	/* Fallback to software crypto */
+	if (bio_data_dir(bio) == WRITE) {
+		/* Encrypt the data now */
+		err = blk_crypto_encrypt_bio(bio_ptr);
+		if (err)
+			goto out_encrypt_err;
+	} else {
+		/* Mark bio as swhandled */
+		bio->bi_crypt_context->processing_ksm = blk_crypto_ksm;
+		bio->bi_crypt_context->crypt_iter = bio->bi_iter;
+		bio->bi_crypt_context->sw_data_unit_num =
+				bio->bi_crypt_context->data_unit_num;
+	}
+	return 0;
+out_encrypt_err:
+	bio_endio(bio);
+	return err;
+}
+
+/**
+ * blk_crypto_endio - clean up bio w.r.t inline encryption during bio_endio
+ *
+ * @bio - the bio to clean up
+ *
+ * If blk_crypto_submit_bio decided to fallback to software crypto for this
+ * bio, we queue the bio for decryption into a workqueue and return false,
+ * and call bio_endio(bio) at a later time (after the bio has been decrypted).
+ *
+ * If the bio is not to be decrypted in software, this function releases the
+ * reference to the keyslot that blk_crypto_submit_bio got.
+ *
+ * Return: true if bio_endio should continue; false otherwise (bio_endio will
+ * be called again when bio has been decrypted).
+ */
+bool blk_crypto_endio(struct bio *bio)
+{
+	if (bio_crypt_swhandled(bio)) {
+		/*
+		 * The only bios that are swhandled when they reach here
+		 * are those with bio_data_dir(bio) == READ, since WRITE
+		 * bios that are encrypted by software fallback are handled
+		 * by blk_crypto_encrypt_endio.
+		 */
+		blk_crypto_queue_decrypt_bio(bio);
+		return false;
+	}
+
+	if (bio_is_encrypted(bio) && bio_crypt_has_keyslot(bio))
+		bio_crypt_ctx_release_keyslot(bio);
+
+	return true;
+}
+
+int __init blk_crypto_init(void)
+{
+	blk_crypto_ksm = keyslot_manager_create(blk_crypto_num_keyslots,
+						&blk_crypto_ksm_ll_ops,
+						NULL);
+	if (!blk_crypto_ksm)
+		goto out_ksm;
+
+	blk_crypto_wq = alloc_workqueue("blk_crypto_wq",
+					WQ_UNBOUND | WQ_HIGHPRI |
+					WQ_MEM_RECLAIM,
+					num_online_cpus());
+	if (!blk_crypto_wq)
+		goto out_wq;
+
+	blk_crypto_keyslots = kcalloc(blk_crypto_num_keyslots,
+				      sizeof(*blk_crypto_keyslots),
+				      GFP_KERNEL);
+	if (!blk_crypto_keyslots)
+		goto out_blk_crypto_keyslots;
+
+	blk_crypto_page_pool =
+		mempool_create_page_pool(num_prealloc_bounce_pg, 0);
+	if (!blk_crypto_page_pool)
+		goto out_bounce_pool;
+
+	blk_crypto_work_mem_cache = KMEM_CACHE(work_mem, SLAB_RECLAIM_ACCOUNT);
+	if (!blk_crypto_work_mem_cache)
+		goto out_work_mem_cache;
+
+	return 0;
+
+out_work_mem_cache:
+	mempool_destroy(blk_crypto_page_pool);
+	blk_crypto_page_pool = NULL;
+out_bounce_pool:
+	kzfree(blk_crypto_keyslots);
+	blk_crypto_keyslots = NULL;
+out_blk_crypto_keyslots:
+	destroy_workqueue(blk_crypto_wq);
+	blk_crypto_wq = NULL;
+out_wq:
+	keyslot_manager_destroy(blk_crypto_ksm);
+	blk_crypto_ksm = NULL;
+out_ksm:
+	pr_warn("No memory for blk-crypto software fallback.");
+	return -ENOMEM;
+}
+
+module_param(blk_crypto_num_keyslots, int, 0);
+MODULE_PARM_DESC(blk_crypto_num_keyslots,
+		 "Number of keyslots for software fallback in blk-crypto.");
+module_param(num_prealloc_bounce_pg, uint, 0);
+MODULE_PARM_DESC(num_prealloc_bounce_pg,
+	"Number of preallocated bounce pages for blk-crypto to use during software fallback encryption");
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 4e664d6441d5..66ad1508911f 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -612,6 +612,8 @@ static inline void bio_crypt_advance(struct bio *bio, unsigned int bytes)
 	}
 }
 
+extern bool bio_crypt_swhandled(struct bio *bio);
+
 static inline bool bio_crypt_has_keyslot(struct bio *bio)
 {
 	return bio->bi_crypt_context->keyslot >= 0;
@@ -717,6 +719,11 @@ static inline void bio_crypt_set_ctx(struct bio *bio,
 				     u64 dun,
 				     unsigned int dun_bits) { }
 
+static inline bool bio_crypt_swhandled(struct bio *bio)
+{
+	return false;
+}
+
 static inline bool bio_crypt_has_keyslot(struct bio *bio)
 {
 	return false;
diff --git a/include/linux/blk-crypto.h b/include/linux/blk-crypto.h
new file mode 100644
index 000000000000..cbb5bea6dcdb
--- /dev/null
+++ b/include/linux/blk-crypto.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#ifndef __LINUX_BLK_CRYPTO_H
+#define __LINUX_BLK_CRYPTO_H
+
+#include <linux/types.h>
+
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+
+struct bio;
+
+int blk_crypto_init(void);
+
+int blk_crypto_submit_bio(struct bio **bio_ptr);
+
+bool blk_crypto_endio(struct bio *bio);
+
+#else /* CONFIG_BLK_INLINE_ENCRYPTION */
+
+static inline int blk_crypto_init(void)
+{
+	return 0;
+}
+
+static inline int blk_crypto_submit_bio(struct bio **bio)
+{
+	return 0;
+}
+
+static inline bool blk_crypto_endio(struct bio *bio)
+{
+	return true;
+}
+
+#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
+
+#endif /* __LINUX_BLK_CRYPTO_H */
-- 
2.22.0.410.gd8fdbe21b5-goog



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[f2fs-dev] [PATCH 4/8] scsi: ufs: UFS driver v2.1 spec crypto additions

[Satya Tangirala via Linux-f2fs-devel]

Add the crypto registers and structs defined in v2.1 of the JEDEC UFSHCI
specification in preparation to add support for inline encryption to
UFS.

Signed-off-by: Satya Tangirala <satyat@google.com>
---
 drivers/scsi/ufs/ufshcd.c |  2 ++
 drivers/scsi/ufs/ufshcd.h |  5 +++
 drivers/scsi/ufs/ufshci.h | 67 +++++++++++++++++++++++++++++++++++++--
 3 files changed, 72 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 3fe3029617a8..36413f97074d 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -4724,6 +4724,8 @@ ufshcd_transfer_rsp_status(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
 	case OCS_MISMATCH_RESP_UPIU_SIZE:
 	case OCS_PEER_COMM_FAILURE:
 	case OCS_FATAL_ERROR:
+	case OCS_INVALID_CRYPTO_CONFIG:
+	case OCS_GENERAL_CRYPTO_ERROR:
 	default:
 		result |= DID_ERROR << 16;
 		dev_err(hba->dev,
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index ecfa898b9ccc..d3b6a6b57a37 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -692,6 +692,11 @@ struct ufs_hba {
 	 * the performance of ongoing read/write operations.
 	 */
 #define UFSHCD_CAP_KEEP_AUTO_BKOPS_ENABLED_EXCEPT_SUSPEND (1 << 5)
+	/*
+	 * This capability allows the host controller driver to use the
+	 * inline crypto engine, if it is present
+	 */
+#define UFSHCD_CAP_CRYPTO (1 << 6)
 
 	struct devfreq *devfreq;
 	struct ufs_clk_scaling clk_scaling;
diff --git a/drivers/scsi/ufs/ufshci.h b/drivers/scsi/ufs/ufshci.h
index 6fa889de5ee5..a757eaf99a19 100644
--- a/drivers/scsi/ufs/ufshci.h
+++ b/drivers/scsi/ufs/ufshci.h
@@ -90,6 +90,7 @@ enum {
 	MASK_64_ADDRESSING_SUPPORT		= 0x01000000,
 	MASK_OUT_OF_ORDER_DATA_DELIVERY_SUPPORT	= 0x02000000,
 	MASK_UIC_DME_TEST_MODE_SUPPORT		= 0x04000000,
+	MASK_CRYPTO_SUPPORT			= 0x10000000,
 };
 
 #define UFS_MASK(mask, offset)		((mask) << (offset))
@@ -143,6 +144,7 @@ enum {
 #define DEVICE_FATAL_ERROR			0x800
 #define CONTROLLER_FATAL_ERROR			0x10000
 #define SYSTEM_BUS_FATAL_ERROR			0x20000
+#define CRYPTO_ENGINE_FATAL_ERROR		0x40000
 
 #define UFSHCD_UIC_PWR_MASK	(UIC_HIBERNATE_ENTER |\
 				UIC_HIBERNATE_EXIT |\
@@ -153,11 +155,13 @@ enum {
 #define UFSHCD_ERROR_MASK	(UIC_ERROR |\
 				DEVICE_FATAL_ERROR |\
 				CONTROLLER_FATAL_ERROR |\
-				SYSTEM_BUS_FATAL_ERROR)
+				SYSTEM_BUS_FATAL_ERROR |\
+				CRYPTO_ENGINE_FATAL_ERROR)
 
 #define INT_FATAL_ERRORS	(DEVICE_FATAL_ERROR |\
 				CONTROLLER_FATAL_ERROR |\
-				SYSTEM_BUS_FATAL_ERROR)
+				SYSTEM_BUS_FATAL_ERROR |\
+				CRYPTO_ENGINE_FATAL_ERROR)
 
 /* HCS - Host Controller Status 30h */
 #define DEVICE_PRESENT				0x1
@@ -316,6 +320,61 @@ enum {
 	INTERRUPT_MASK_ALL_VER_21	= 0x71FFF,
 };
 
+/* CCAP - Crypto Capability 100h */
+union ufs_crypto_capabilities {
+	__le32 reg_val;
+	struct {
+		u8 num_crypto_cap;
+		u8 config_count;
+		u8 reserved;
+		u8 config_array_ptr;
+	};
+};
+
+enum ufs_crypto_key_size {
+	UFS_CRYPTO_KEY_SIZE_INVALID	= 0x0,
+	UFS_CRYPTO_KEY_SIZE_128		= 0x1,
+	UFS_CRYPTO_KEY_SIZE_192		= 0x2,
+	UFS_CRYPTO_KEY_SIZE_256		= 0x3,
+	UFS_CRYPTO_KEY_SIZE_512		= 0x4,
+};
+
+enum ufs_crypto_alg {
+	UFS_CRYPTO_ALG_AES_XTS			= 0x0,
+	UFS_CRYPTO_ALG_BITLOCKER_AES_CBC	= 0x1,
+	UFS_CRYPTO_ALG_AES_ECB			= 0x2,
+	UFS_CRYPTO_ALG_ESSIV_AES_CBC		= 0x3,
+};
+
+/* x-CRYPTOCAP - Crypto Capability X */
+union ufs_crypto_cap_entry {
+	__le32 reg_val;
+	struct {
+		u8 algorithm_id;
+		u8 sdus_mask; /* Supported data unit size mask */
+		u8 key_size;
+		u8 reserved;
+	};
+};
+
+#define UFS_CRYPTO_CONFIGURATION_ENABLE (1 << 7)
+#define UFS_CRYPTO_KEY_MAX_SIZE 64
+/* x-CRYPTOCFG - Crypto Configuration X */
+union ufs_crypto_cfg_entry {
+	__le32 reg_val[32];
+	struct {
+		u8 crypto_key[UFS_CRYPTO_KEY_MAX_SIZE];
+		u8 data_unit_size;
+		u8 crypto_cap_idx;
+		u8 reserved_1;
+		u8 config_enable;
+		u8 reserved_multi_host;
+		u8 reserved_2;
+		u8 vsb[2];
+		u8 reserved_3[56];
+	};
+};
+
 /*
  * Request Descriptor Definitions
  */
@@ -337,6 +396,7 @@ enum {
 	UTP_NATIVE_UFS_COMMAND		= 0x10000000,
 	UTP_DEVICE_MANAGEMENT_FUNCTION	= 0x20000000,
 	UTP_REQ_DESC_INT_CMD		= 0x01000000,
+	UTP_REQ_DESC_CRYPTO_ENABLE_CMD	= 0x00800000,
 };
 
 /* UTP Transfer Request Data Direction (DD) */
@@ -356,6 +416,9 @@ enum {
 	OCS_PEER_COMM_FAILURE		= 0x5,
 	OCS_ABORTED			= 0x6,
 	OCS_FATAL_ERROR			= 0x7,
+	OCS_DEVICE_FATAL_ERROR		= 0x8,
+	OCS_INVALID_CRYPTO_CONFIG	= 0x9,
+	OCS_GENERAL_CRYPTO_ERROR	= 0xA,
 	OCS_INVALID_COMMAND_STATUS	= 0x0F,
 	MASK_OCS			= 0x0F,
 };
-- 
2.22.0.410.gd8fdbe21b5-goog



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[f2fs-dev] [PATCH 5/8] scsi: ufs: UFS crypto API

[Satya Tangirala via Linux-f2fs-devel]

Introduce functions to manipulate UFS inline encryption hardware
in line with the JEDEC UFSHCI v2.1 specification and to work with the
block keyslot manager.

Signed-off-by: Satya Tangirala <satyat@google.com>
---
 drivers/scsi/ufs/Kconfig         |  10 +
 drivers/scsi/ufs/Makefile        |   1 +
 drivers/scsi/ufs/ufshcd-crypto.c | 435 +++++++++++++++++++++++++++++++
 drivers/scsi/ufs/ufshcd-crypto.h |  86 ++++++
 drivers/scsi/ufs/ufshcd.h        |  18 ++
 5 files changed, 550 insertions(+)
 create mode 100644 drivers/scsi/ufs/ufshcd-crypto.c
 create mode 100644 drivers/scsi/ufs/ufshcd-crypto.h

diff --git a/drivers/scsi/ufs/Kconfig b/drivers/scsi/ufs/Kconfig
index 0b845ab7c3bf..861aabfe791b 100644
--- a/drivers/scsi/ufs/Kconfig
+++ b/drivers/scsi/ufs/Kconfig
@@ -150,3 +150,13 @@ config SCSI_UFS_BSG
 
 	  Select this if you need a bsg device node for your UFS controller.
 	  If unsure, say N.
+
+config SCSI_UFS_CRYPTO
+	bool "UFS Crypto Engine Support"
+	depends on SCSI_UFSHCD && BLK_INLINE_ENCRYPTION
+	help
+	  Enable Crypto Engine Support in UFS.
+	  Enabling this makes it possible for the kernel to use the crypto
+	  capabilities of the UFS device (if present) to perform crypto
+	  operations on data being transferred to/from the device.
+
diff --git a/drivers/scsi/ufs/Makefile b/drivers/scsi/ufs/Makefile
index 2a9097939bcb..094c39989a37 100644
--- a/drivers/scsi/ufs/Makefile
+++ b/drivers/scsi/ufs/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_SCSI_UFSHCD_PCI) += ufshcd-pci.o
 obj-$(CONFIG_SCSI_UFSHCD_PLATFORM) += ufshcd-pltfrm.o
 obj-$(CONFIG_SCSI_UFS_HISI) += ufs-hisi.o
 obj-$(CONFIG_SCSI_UFS_MEDIATEK) += ufs-mediatek.o
+ufshcd-core-$(CONFIG_SCSI_UFS_CRYPTO) += ufshcd-crypto.o
diff --git a/drivers/scsi/ufs/ufshcd-crypto.c b/drivers/scsi/ufs/ufshcd-crypto.c
new file mode 100644
index 000000000000..834c57ca912a
--- /dev/null
+++ b/drivers/scsi/ufs/ufshcd-crypto.c
@@ -0,0 +1,435 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#include <crypto/algapi.h>
+
+#include "ufshcd.h"
+#include "ufshcd-crypto.h"
+
+static bool ufshcd_cap_idx_valid(struct ufs_hba *hba, unsigned int cap_idx)
+{
+	return cap_idx < hba->crypto_capabilities.num_crypto_cap;
+}
+
+static u8 get_data_unit_size_mask(unsigned int data_unit_size)
+{
+	if (data_unit_size < 512 || data_unit_size > 65536 ||
+	    !is_power_of_2(data_unit_size))
+		return 0;
+
+	return data_unit_size / 512;
+}
+
+static size_t get_keysize_bytes(enum ufs_crypto_key_size size)
+{
+	switch (size) {
+	case UFS_CRYPTO_KEY_SIZE_128: return 16;
+	case UFS_CRYPTO_KEY_SIZE_192: return 24;
+	case UFS_CRYPTO_KEY_SIZE_256: return 32;
+	case UFS_CRYPTO_KEY_SIZE_512: return 64;
+	default: return 0;
+	}
+}
+
+static int ufshcd_crypto_cap_find(void *hba_p,
+			   enum blk_crypt_mode_num crypt_mode,
+			   unsigned int data_unit_size)
+{
+	struct ufs_hba *hba = hba_p;
+	enum ufs_crypto_alg ufs_alg;
+	u8 data_unit_mask;
+	int cap_idx;
+	enum ufs_crypto_key_size ufs_key_size;
+	union ufs_crypto_cap_entry *ccap_array = hba->crypto_cap_array;
+
+	if (!ufshcd_hba_is_crypto_supported(hba))
+		return -EINVAL;
+
+	switch (crypt_mode) {
+	case BLK_ENCRYPTION_MODE_AES_256_XTS:
+		ufs_alg = UFS_CRYPTO_ALG_AES_XTS;
+		ufs_key_size = UFS_CRYPTO_KEY_SIZE_256;
+		break;
+	/*
+	 * case BLK_CRYPTO_ALG_BITLOCKER_AES_CBC:
+	 *	ufs_alg = UFS_CRYPTO_ALG_BITLOCKER_AES_CBC;
+	 *	break;
+	 * case INLINECRYPT_ALG_AES_ECB:
+	 *	ufs_alg = UFS_CRYPTO_ALG_AES_ECB;
+	 *	break;
+	 * case INLINECRYPT_ALG_ESSIV_AES_CBC:
+	 *	ufs_alg = UFS_CRYPTO_ALG_ESSIV_AES_CBC;
+	 *	break;
+	 */
+	default: return -EINVAL;
+	}
+
+	data_unit_mask = get_data_unit_size_mask(data_unit_size);
+
+	/*
+	 * TODO: We can replace this for loop entirely by constructing
+	 * a table on init that translates blk_crypt_mode to
+	 * ufs crypt alg numbers. (By assuming that each alg/keysize combo
+	 * appears only once in the ufs crypto caps array.)
+	 */
+	for (cap_idx = 0; cap_idx < hba->crypto_capabilities.num_crypto_cap;
+	     cap_idx++) {
+		if (ccap_array[cap_idx].algorithm_id == ufs_alg &&
+		    (ccap_array[cap_idx].sdus_mask & data_unit_mask) &&
+		    ccap_array[cap_idx].key_size == ufs_key_size)
+			return cap_idx;
+	}
+
+	return -EINVAL;
+}
+
+/**
+ * ufshcd_crypto_cfg_entry_write_key - Write a key into a crypto_cfg_entry
+ *
+ *	Writes the key with the appropriate format - for AES_XTS,
+ *	the first half of the key is copied as is, the second half is
+ *	copied with an offset halfway into the cfg->crypto_key array.
+ *	For the other supported crypto algs, the key is just copied.
+ *
+ * @cfg: The crypto config to write to
+ * @key: The key to write
+ * @cap: The crypto capability (which specifies the crypto alg and key size)
+ *
+ * Returns 0 on success, or -EINVAL
+ */
+static int ufshcd_crypto_cfg_entry_write_key(union ufs_crypto_cfg_entry *cfg,
+					     const u8 *key,
+					     union ufs_crypto_cap_entry cap)
+{
+	size_t key_size_bytes = get_keysize_bytes(cap.key_size);
+
+	if (key_size_bytes == 0)
+		return -EINVAL;
+
+	switch (cap.algorithm_id) {
+	case UFS_CRYPTO_ALG_AES_XTS:
+		key_size_bytes *= 2;
+		if (key_size_bytes > UFS_CRYPTO_KEY_MAX_SIZE)
+			return -EINVAL;
+
+		memcpy(cfg->crypto_key, key, key_size_bytes/2);
+		memcpy(cfg->crypto_key + UFS_CRYPTO_KEY_MAX_SIZE/2,
+		       key + key_size_bytes/2, key_size_bytes/2);
+		return 0;
+	case UFS_CRYPTO_ALG_BITLOCKER_AES_CBC: // fallthrough
+	case UFS_CRYPTO_ALG_AES_ECB: // fallthrough
+	case UFS_CRYPTO_ALG_ESSIV_AES_CBC:
+		memcpy(cfg->crypto_key, key, key_size_bytes);
+		return 0;
+	}
+
+	return -EINVAL;
+}
+
+static void program_key(struct ufs_hba *hba,
+			const union ufs_crypto_cfg_entry *cfg,
+			int slot)
+{
+	int i;
+	u32 slot_offset = hba->crypto_cfg_register + slot * sizeof(*cfg);
+
+	/* Clear the dword 16 */
+	ufshcd_writel(hba, 0, slot_offset + 16 * sizeof(cfg->reg_val[0]));
+	/* Ensure that CFGE is cleared before programming the key */
+	wmb();
+	for (i = 0; i < 16; i++) {
+		ufshcd_writel(hba, le32_to_cpu(cfg->reg_val[i]),
+			      slot_offset + i * sizeof(cfg->reg_val[0]));
+		/* Spec says each dword in key must be written sequentially */
+		wmb();
+	}
+	/* Write dword 17 */
+	ufshcd_writel(hba, le32_to_cpu(cfg->reg_val[17]),
+		      slot_offset + 17 * sizeof(cfg->reg_val[0]));
+	/* Dword 16 must be written last */
+	wmb();
+	/* Write dword 16 */
+	ufshcd_writel(hba, le32_to_cpu(cfg->reg_val[16]),
+		      slot_offset + 16 * sizeof(cfg->reg_val[0]));
+	wmb();
+}
+
+static int ufshcd_crypto_keyslot_program(void *hba_p, const u8 *key,
+					 enum blk_crypt_mode_num crypt_mode,
+					 unsigned int data_unit_size,
+					 unsigned int slot)
+{
+	struct ufs_hba *hba = hba_p;
+	int err = 0;
+	u8 data_unit_mask;
+	union ufs_crypto_cfg_entry cfg;
+	union ufs_crypto_cfg_entry *cfg_arr = hba->crypto_cfgs;
+	int cap_idx;
+
+	cap_idx = ufshcd_crypto_cap_find(hba_p, crypt_mode,
+					       data_unit_size);
+
+	if (!ufshcd_is_crypto_enabled(hba) ||
+	    !ufshcd_keyslot_valid(hba, slot) ||
+	    !ufshcd_cap_idx_valid(hba, cap_idx))
+		return -EINVAL;
+
+	data_unit_mask = get_data_unit_size_mask(data_unit_size);
+
+	if (!(data_unit_mask & hba->crypto_cap_array[cap_idx].sdus_mask))
+		return -EINVAL;
+
+	memset(&cfg, 0, sizeof(cfg));
+	cfg.data_unit_size = data_unit_mask;
+	cfg.crypto_cap_idx = cap_idx;
+	cfg.config_enable |= UFS_CRYPTO_CONFIGURATION_ENABLE;
+
+	err = ufshcd_crypto_cfg_entry_write_key(&cfg, key,
+				hba->crypto_cap_array[cap_idx]);
+	if (err)
+		return err;
+
+	program_key(hba, &cfg, slot);
+
+	memcpy(&cfg_arr[slot], &cfg, sizeof(cfg));
+	memzero_explicit(&cfg, sizeof(cfg));
+
+	return 0;
+}
+
+static int ufshcd_crypto_keyslot_find(void *hba_p,
+				      const u8 *key,
+				      enum blk_crypt_mode_num crypt_mode,
+				      unsigned int data_unit_size)
+{
+	struct ufs_hba *hba = hba_p;
+	int err = 0;
+	int slot;
+	u8 data_unit_mask;
+	union ufs_crypto_cfg_entry cfg;
+	union ufs_crypto_cfg_entry *cfg_arr = hba->crypto_cfgs;
+	int cap_idx;
+
+	cap_idx = ufshcd_crypto_cap_find(hba_p, crypt_mode,
+					       data_unit_size);
+
+	if (!ufshcd_is_crypto_enabled(hba) ||
+	    !ufshcd_cap_idx_valid(hba, cap_idx))
+		return -EINVAL;
+
+	data_unit_mask = get_data_unit_size_mask(data_unit_size);
+
+	if (!(data_unit_mask & hba->crypto_cap_array[cap_idx].sdus_mask))
+		return -EINVAL;
+
+	memset(&cfg, 0, sizeof(cfg));
+	err = ufshcd_crypto_cfg_entry_write_key(&cfg, key,
+					hba->crypto_cap_array[cap_idx]);
+
+	if (err)
+		return -EINVAL;
+
+	for (slot = 0; slot < NUM_KEYSLOTS(hba); slot++) {
+		if ((cfg_arr[slot].config_enable &
+		     UFS_CRYPTO_CONFIGURATION_ENABLE) &&
+		    data_unit_mask == cfg_arr[slot].data_unit_size &&
+		    cap_idx == cfg_arr[slot].crypto_cap_idx &&
+		    !crypto_memneq(&cfg.crypto_key, cfg_arr[slot].crypto_key,
+				  UFS_CRYPTO_KEY_MAX_SIZE)) {
+			memzero_explicit(&cfg, sizeof(cfg));
+			return slot;
+		}
+	}
+
+	memzero_explicit(&cfg, sizeof(cfg));
+	return -ENOKEY;
+}
+
+static int ufshcd_crypto_keyslot_evict(void *hba_p, const u8 *key,
+				       enum blk_crypt_mode_num crypt_mode,
+				       unsigned int data_unit_size,
+				       unsigned int slot)
+{
+	struct ufs_hba *hba = hba_p;
+	int i = 0;
+	u32 reg_base;
+	union ufs_crypto_cfg_entry *cfg_arr = hba->crypto_cfgs;
+
+	if (!ufshcd_is_crypto_enabled(hba) ||
+	    !ufshcd_keyslot_valid(hba, slot))
+		return -EINVAL;
+
+	memset(&cfg_arr[slot], 0, sizeof(cfg_arr[slot]));
+	reg_base = hba->crypto_cfg_register + slot * sizeof(cfg_arr[0]);
+
+	/*
+	 * Clear the crypto cfg on the device. Clearing CFGE
+	 * might not be sufficient, so just clear the entire cfg.
+	 */
+	for (i = 0; i < sizeof(cfg_arr[0]); i += sizeof(__le32))
+		ufshcd_writel(hba, 0, reg_base + i);
+	wmb();
+
+	return 0;
+}
+
+static bool ufshcd_crypt_mode_supported(void *hba_p,
+					 enum blk_crypt_mode_num crypt_mode,
+					 unsigned int data_unit_size)
+{
+	return ufshcd_crypto_cap_find(hba_p, crypt_mode, data_unit_size) >= 0;
+}
+
+void ufshcd_crypto_enable(struct ufs_hba *hba)
+{
+	union ufs_crypto_cfg_entry *cfg_arr = hba->crypto_cfgs;
+	int slot;
+
+	if (!ufshcd_hba_is_crypto_supported(hba))
+		return;
+
+	hba->caps |= UFSHCD_CAP_CRYPTO;
+	/*
+	 * Reset might clear all keys, so reprogram all the keys.
+	 * Also serves to clear keys on driver init.
+	 */
+	for (slot = 0; slot < NUM_KEYSLOTS(hba); slot++)
+		program_key(hba, &cfg_arr[slot], slot);
+}
+
+void ufshcd_crypto_disable(struct ufs_hba *hba)
+{
+	hba->caps &= ~UFSHCD_CAP_CRYPTO;
+}
+
+
+/**
+ * ufshcd_hba_init_crypto - Read crypto capabilities, init crypto fields in hba
+ * @hba: Per adapter instance
+ *
+ * Returns 0 on success. Returns -ENODEV if such capabilties don't exist, and
+ * -ENOMEM upon OOM.
+ */
+int ufshcd_hba_init_crypto(struct ufs_hba *hba)
+{
+	int cap_idx = 0;
+	int err = 0;
+
+	/* Default to disabling crypto */
+	hba->caps &= ~UFSHCD_CAP_CRYPTO;
+
+	if (!(hba->capabilities & MASK_CRYPTO_SUPPORT)) {
+		err = -ENODEV;
+		goto out;
+	}
+
+	/*
+	 * Crypto Capabilities should never be 0, because the
+	 * config_array_ptr > 04h. So we use a 0 value to indicate that
+	 * crypto init failed, and can't be enabled.
+	 */
+	hba->crypto_capabilities.reg_val =
+			cpu_to_le32(ufshcd_readl(hba, REG_UFS_CCAP));
+	hba->crypto_cfg_register =
+		(u32)hba->crypto_capabilities.config_array_ptr * 0x100;
+	hba->crypto_cap_array =
+		devm_kcalloc(hba->dev,
+			     hba->crypto_capabilities.num_crypto_cap,
+			     sizeof(hba->crypto_cap_array[0]),
+			     GFP_KERNEL);
+	if (!hba->crypto_cap_array) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	hba->crypto_cfgs =
+		devm_kcalloc(hba->dev,
+			     hba->crypto_capabilities.config_count + 1,
+			     sizeof(hba->crypto_cfgs[0]),
+			     GFP_KERNEL);
+	if (!hba->crypto_cfgs) {
+		err = -ENOMEM;
+		goto out_cfg_mem;
+	}
+
+	/*
+	 * Store all the capabilities now so that we don't need to repeatedly
+	 * access the device each time we want to know its capabilities
+	 */
+	for (cap_idx = 0; cap_idx < hba->crypto_capabilities.num_crypto_cap;
+	     cap_idx++) {
+		hba->crypto_cap_array[cap_idx].reg_val =
+			cpu_to_le32(ufshcd_readl(hba,
+						 REG_UFS_CRYPTOCAP +
+						 cap_idx * sizeof(__le32)));
+	}
+
+	hba->ksm = NULL;
+	mutex_init(&hba->ksm_lock);
+	hba->ksm_num_refs = 0;
+
+	return 0;
+out_cfg_mem:
+	devm_kfree(hba->dev, hba->crypto_cap_array);
+out:
+	// TODO: print error?
+	/* Indicate that init failed by setting crypto_capabilities to 0 */
+	hba->crypto_capabilities.reg_val = 0;
+	return err;
+}
+
+static const struct keyslot_mgmt_ll_ops ufshcd_ksm_ops = {
+	.keyslot_program	= ufshcd_crypto_keyslot_program,
+	.keyslot_evict		= ufshcd_crypto_keyslot_evict,
+	.keyslot_find		= ufshcd_crypto_keyslot_find,
+	.crypt_mode_supported	= ufshcd_crypt_mode_supported,
+};
+
+void ufshcd_crypto_setup_rq_keyslot_manager(struct ufs_hba *hba,
+					    struct request_queue *q)
+{
+	if (!ufshcd_hba_is_crypto_supported(hba))
+		return;
+
+	if (q) {
+		mutex_lock(&hba->ksm_lock);
+		if (!hba->ksm) {
+			hba->ksm = keyslot_manager_create(
+				hba->crypto_capabilities.config_count + 1,
+				&ufshcd_ksm_ops, hba);
+			hba->ksm_num_refs = 0;
+		}
+		hba->ksm_num_refs++;
+		mutex_unlock(&hba->ksm_lock);
+		q->ksm = hba->ksm;
+	}
+	/*
+	 * If we fail we make it look like
+	 * crypto is not supported, which will avoid issues
+	 * with reset
+	 */
+	if (!q || !q->ksm) {
+		ufshcd_crypto_disable(hba);
+		hba->crypto_capabilities.reg_val = 0;
+		devm_kfree(hba->dev, hba->crypto_cap_array);
+		devm_kfree(hba->dev, hba->crypto_cfgs);
+	}
+}
+
+void ufshcd_crypto_destroy_rq_keyslot_manager(struct ufs_hba *hba,
+					      struct request_queue *q)
+{
+	if (q && q->ksm) {
+		q->ksm = NULL;
+		mutex_lock(&hba->ksm_lock);
+		hba->ksm_num_refs--;
+		if (hba->ksm_num_refs == 0) {
+			keyslot_manager_destroy(hba->ksm);
+			hba->ksm = NULL;
+		}
+		mutex_unlock(&hba->ksm_lock);
+	}
+}
+
diff --git a/drivers/scsi/ufs/ufshcd-crypto.h b/drivers/scsi/ufs/ufshcd-crypto.h
new file mode 100644
index 000000000000..73ddc8e493fb
--- /dev/null
+++ b/drivers/scsi/ufs/ufshcd-crypto.h
@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright 2019 Google LLC
+ */
+
+#ifndef _UFSHCD_CRYPTO_H
+#define _UFSHCD_CRYPTO_H
+
+struct ufs_hba;
+
+#ifdef CONFIG_SCSI_UFS_CRYPTO
+#include <linux/keyslot-manager.h>
+
+#include "ufshci.h"
+
+#define NUM_KEYSLOTS(hba) (hba->crypto_capabilities.config_count + 1)
+
+static inline bool ufshcd_keyslot_valid(struct ufs_hba *hba, unsigned int slot)
+{
+	/*
+	 * The actual number of configurations supported is (CFGC+1), so slot
+	 * numbers range from 0 to config_count inclusive.
+	 */
+	return slot < NUM_KEYSLOTS(hba);
+}
+
+static inline bool ufshcd_hba_is_crypto_supported(struct ufs_hba *hba)
+{
+	return hba->crypto_capabilities.reg_val != 0;
+}
+
+static inline bool ufshcd_is_crypto_enabled(struct ufs_hba *hba)
+{
+	return hba->caps & UFSHCD_CAP_CRYPTO;
+}
+
+void ufshcd_crypto_enable(struct ufs_hba *hba);
+
+void ufshcd_crypto_disable(struct ufs_hba *hba);
+
+int ufshcd_hba_init_crypto(struct ufs_hba *hba);
+
+void ufshcd_crypto_setup_rq_keyslot_manager(struct ufs_hba *hba,
+					    struct request_queue *q);
+
+void ufshcd_crypto_destroy_rq_keyslot_manager(struct ufs_hba *hba,
+					      struct request_queue *q);
+
+#else /* CONFIG_SCSI_UFS_CRYPTO */
+
+static inline bool ufshcd_keyslot_valid(struct ufs_hba *hba,
+					unsigned int slot)
+{
+	return false;
+}
+
+static inline bool ufshcd_hba_is_crypto_supported(struct ufs_hba *hba)
+{
+	return false;
+}
+
+static inline bool ufshcd_is_crypto_enabled(struct ufs_hba *hba)
+{
+	return false;
+}
+
+static inline void ufshcd_crypto_enable(struct ufs_hba *hba) { }
+
+static inline void ufshcd_crypto_disable(struct ufs_hba *hba) { }
+
+static inline int ufshcd_hba_init_crypto(struct ufs_hba *hba)
+{
+	return 0;
+}
+
+static inline void ufshcd_crypto_setup_rq_keyslot_manager(
+					struct ufs_hba *hba,
+					struct request_queue *q) { }
+
+static inline void ufshcd_crypto_destroy_rq_keyslot_manager(
+				struct ufs_hba *hba,
+				struct request_queue *q) { }
+
+#endif /* CONFIG_SCSI_UFS_CRYPTO */
+
+#endif /* _UFSHCD_CRYPTO_H */
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index d3b6a6b57a37..ef62b3ba03fd 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -501,6 +501,13 @@ struct ufs_stats {
  * @is_urgent_bkops_lvl_checked: keeps track if the urgent bkops level for
  *  device is known or not.
  * @scsi_block_reqs_cnt: reference counting for scsi block requests
+ * @crypto_capabilities: Content of crypto capabilities register (0x100)
+ * @crypto_cap_array: Array of crypto capabilities
+ * @crypto_cfg_register: Start of the crypto cfg array
+ * @crypto_cfgs: Array of crypto configurations (i.e. config for each slot)
+ * @ksm: the keyslot manager tied to this hba
+ * @ksm_lock: lock to protect initialization and refcount of ksm
+ * @ksm_num_refs: refcount for ksm
  */
 struct ufs_hba {
 	void __iomem *mmio_base;
@@ -711,6 +718,17 @@ struct ufs_hba {
 
 	struct device		bsg_dev;
 	struct request_queue	*bsg_queue;
+
+#ifdef CONFIG_SCSI_UFS_CRYPTO
+	/* crypto */
+	union ufs_crypto_capabilities crypto_capabilities;
+	union ufs_crypto_cap_entry *crypto_cap_array;
+	u32 crypto_cfg_register;
+	union ufs_crypto_cfg_entry *crypto_cfgs;
+	struct keyslot_manager *ksm;
+	struct mutex ksm_lock;
+	unsigned int ksm_num_refs;
+#endif /* CONFIG_SCSI_UFS_CRYPTO */
 };
 
 /* Returns true if clocks can be gated. Otherwise false */
-- 
2.22.0.410.gd8fdbe21b5-goog



_______________________________________________
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Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

[f2fs-dev] [PATCH 6/8] scsi: ufs: Add inline encryption support to UFS

[Satya Tangirala via Linux-f2fs-devel]

Wire up ufshcd.c with the UFS Crypto API, the block layer inline
encryption additions and the keyslot manager.

Signed-off-by: Satya Tangirala <satyat@google.com>
---
 drivers/scsi/ufs/ufshcd.c | 82 ++++++++++++++++++++++++++++++++++++---
 drivers/scsi/ufs/ufshcd.h |  6 +++
 2 files changed, 83 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 36413f97074d..492e9db6b50f 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -47,6 +47,7 @@
 #include "unipro.h"
 #include "ufs-sysfs.h"
 #include "ufs_bsg.h"
+#include "ufshcd-crypto.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/ufs.h>
@@ -855,7 +856,14 @@ static void ufshcd_enable_run_stop_reg(struct ufs_hba *hba)
  */
 static inline void ufshcd_hba_start(struct ufs_hba *hba)
 {
-	ufshcd_writel(hba, CONTROLLER_ENABLE, REG_CONTROLLER_ENABLE);
+	u32 val = CONTROLLER_ENABLE;
+
+	if (ufshcd_hba_is_crypto_supported(hba)) {
+		ufshcd_crypto_enable(hba);
+		val |= CRYPTO_GENERAL_ENABLE;
+	}
+
+	ufshcd_writel(hba, val, REG_CONTROLLER_ENABLE);
 }
 
 /**
@@ -2209,9 +2217,21 @@ static void ufshcd_prepare_req_desc_hdr(struct ufshcd_lrb *lrbp,
 		dword_0 |= UTP_REQ_DESC_INT_CMD;
 
 	/* Transfer request descriptor header fields */
+	if (lrbp->crypto_enable) {
+		dword_0 |= UTP_REQ_DESC_CRYPTO_ENABLE_CMD;
+		dword_0 |= lrbp->crypto_key_slot;
+		req_desc->header.dword_1 =
+			cpu_to_le32((u32)lrbp->data_unit_num);
+		req_desc->header.dword_3 =
+			cpu_to_le32((u32)(lrbp->data_unit_num >> 32));
+	} else {
+		/* dword_1 and dword_3 are reserved, hence they are set to 0 */
+		req_desc->header.dword_1 = 0;
+		req_desc->header.dword_3 = 0;
+	}
+
 	req_desc->header.dword_0 = cpu_to_le32(dword_0);
-	/* dword_1 is reserved, hence it is set to 0 */
-	req_desc->header.dword_1 = 0;
+
 	/*
 	 * assigning invalid value for command status. Controller
 	 * updates OCS on command completion, with the command
@@ -2219,8 +2239,6 @@ static void ufshcd_prepare_req_desc_hdr(struct ufshcd_lrb *lrbp,
 	 */
 	req_desc->header.dword_2 =
 		cpu_to_le32(OCS_INVALID_COMMAND_STATUS);
-	/* dword_3 is reserved, hence it is set to 0 */
-	req_desc->header.dword_3 = 0;
 
 	req_desc->prd_table_length = 0;
 }
@@ -2380,6 +2398,37 @@ static inline u16 ufshcd_upiu_wlun_to_scsi_wlun(u8 upiu_wlun_id)
 	return (upiu_wlun_id & ~UFS_UPIU_WLUN_ID) | SCSI_W_LUN_BASE;
 }
 
+static inline int ufshcd_prepare_lrbp_crypto(struct ufs_hba *hba,
+					     struct scsi_cmnd *cmd,
+					     struct ufshcd_lrb *lrbp)
+{
+	int key_slot;
+
+	if (!cmd->request->bio ||
+	    !bio_crypt_should_process(cmd->request->bio, cmd->request->q)) {
+		lrbp->crypto_enable = false;
+		return 0;
+	}
+
+	if (WARN_ON(!ufshcd_is_crypto_enabled(hba))) {
+		/*
+		 * Upper layer asked us to do inline encryption
+		 * but that isn't enabled, so we fail this request.
+		 */
+		return -EINVAL;
+	}
+	key_slot = bio_crypt_get_keyslot(cmd->request->bio);
+	if (!ufshcd_keyslot_valid(hba, key_slot))
+		return -EINVAL;
+
+	lrbp->crypto_enable = true;
+	lrbp->crypto_key_slot = key_slot;
+	lrbp->data_unit_num = bio_crypt_data_unit_num(cmd->request->bio);
+
+	return 0;
+}
+
+
 /**
  * ufshcd_queuecommand - main entry point for SCSI requests
  * @host: SCSI host pointer
@@ -2467,6 +2516,13 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
 	lrbp->task_tag = tag;
 	lrbp->lun = ufshcd_scsi_to_upiu_lun(cmd->device->lun);
 	lrbp->intr_cmd = !ufshcd_is_intr_aggr_allowed(hba) ? true : false;
+
+	err = ufshcd_prepare_lrbp_crypto(hba, cmd, lrbp);
+	if (err) {
+		lrbp->cmd = NULL;
+		clear_bit_unlock(tag, &hba->lrb_in_use);
+		goto out;
+	}
 	lrbp->req_abort_skip = false;
 
 	ufshcd_comp_scsi_upiu(hba, lrbp);
@@ -2500,6 +2556,7 @@ static int ufshcd_compose_dev_cmd(struct ufs_hba *hba,
 	lrbp->task_tag = tag;
 	lrbp->lun = 0; /* device management cmd is not specific to any LUN */
 	lrbp->intr_cmd = true; /* No interrupt aggregation */
+	lrbp->crypto_enable = false; /* No crypto operations */
 	hba->dev_cmd.type = cmd_type;
 
 	return ufshcd_comp_devman_upiu(hba, lrbp);
@@ -4192,6 +4249,8 @@ static inline void ufshcd_hba_stop(struct ufs_hba *hba, bool can_sleep)
 {
 	int err;
 
+	ufshcd_crypto_disable(hba);
+
 	ufshcd_writel(hba, CONTROLLER_DISABLE,  REG_CONTROLLER_ENABLE);
 	err = ufshcd_wait_for_register(hba, REG_CONTROLLER_ENABLE,
 					CONTROLLER_ENABLE, CONTROLLER_DISABLE,
@@ -4585,10 +4644,13 @@ static int ufshcd_change_queue_depth(struct scsi_device *sdev, int depth)
 static int ufshcd_slave_configure(struct scsi_device *sdev)
 {
 	struct request_queue *q = sdev->request_queue;
+	struct ufs_hba *hba = shost_priv(sdev->host);
 
 	blk_queue_update_dma_pad(q, PRDT_DATA_BYTE_COUNT_PAD - 1);
 	blk_queue_max_segment_size(q, PRDT_DATA_BYTE_COUNT_MAX);
 
+	ufshcd_crypto_setup_rq_keyslot_manager(hba, q);
+
 	return 0;
 }
 
@@ -4599,6 +4661,7 @@ static int ufshcd_slave_configure(struct scsi_device *sdev)
 static void ufshcd_slave_destroy(struct scsi_device *sdev)
 {
 	struct ufs_hba *hba;
+	struct request_queue *q = sdev->request_queue;
 
 	hba = shost_priv(sdev->host);
 	/* Drop the reference as it won't be needed anymore */
@@ -4609,6 +4672,8 @@ static void ufshcd_slave_destroy(struct scsi_device *sdev)
 		hba->sdev_ufs_device = NULL;
 		spin_unlock_irqrestore(hba->host->host_lock, flags);
 	}
+
+	ufshcd_crypto_destroy_rq_keyslot_manager(hba, q);
 }
 
 /**
@@ -8293,6 +8358,13 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 		goto exit_gating;
 	}
 
+	/* Init crypto */
+	err = ufshcd_hba_init_crypto(hba);
+	if (err) {
+		dev_err(hba->dev, "crypto setup failed\n");
+		goto out_remove_scsi_host;
+	}
+
 	/* Host controller enable */
 	err = ufshcd_hba_enable(hba);
 	if (err) {
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index ef62b3ba03fd..ab9c1191c206 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -167,6 +167,9 @@ struct ufs_pm_lvl_states {
  * @intr_cmd: Interrupt command (doesn't participate in interrupt aggregation)
  * @issue_time_stamp: time stamp for debug purposes
  * @compl_time_stamp: time stamp for statistics
+ * @crypto_enable: whether or not the request needs inline crypto operations
+ * @crypto_key_slot: the key slot to use for inline crypto
+ * @data_unit_num: the data unit number for the first block for inline crypto
  * @req_abort_skip: skip request abort task flag
  */
 struct ufshcd_lrb {
@@ -191,6 +194,9 @@ struct ufshcd_lrb {
 	bool intr_cmd;
 	ktime_t issue_time_stamp;
 	ktime_t compl_time_stamp;
+	bool crypto_enable;
+	u8 crypto_key_slot;
+	u64 data_unit_num;
 
 	bool req_abort_skip;
 };
-- 
2.22.0.410.gd8fdbe21b5-goog



_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

[f2fs-dev] [PATCH 7/8] fscrypt: wire up fscrypt to use blk-crypto

[Satya Tangirala via Linux-f2fs-devel]

Introduce fscrypt_set_bio_crypt_ctx for filesystems to call to set up
encryption contexts in bios, and fscrypt_evict_crypt_key to evict
the encryption context associated with an inode.

Inline encryption is controlled by a policy flag in the fscrypt_info
in the inode, and filesystems may check if an inode should use inline
encryption by calling fscrypt_inode_is_inline_crypted. Files can be marked
as inline encrypted from userspace by appropriately modifying the flags
(OR-ing FS_POLICY_FLAGS_INLINE_ENCRYPTION to it) in the fscrypt_policy
passed to fscrypt_ioctl_set_policy.

To test inline encryption with the fscrypt dummy context, add
ctx.flags |= FS_POLICY_FLAGS_INLINE_ENCRYPTION
when setting up the dummy context in fs/crypto/keyinfo.c.

Note that blk-crypto will fall back to software en/decryption in the
absence of inline crypto hardware, so setting up the ctx.flags in the
dummy context without inline crypto hardware serves as a test for
the software fallback in blk-crypto.

Signed-off-by: Satya Tangirala <satyat@google.com>
---
 fs/crypto/Kconfig           |   6 ++
 fs/crypto/bio.c             | 138 +++++++++++++++++++++++++++++++-----
 fs/crypto/crypto.c          |   4 ++
 fs/crypto/fscrypt_private.h |  11 +++
 fs/crypto/keyinfo.c         |  94 +++++++++++++++++-------
 fs/crypto/policy.c          |  10 +++
 include/linux/fscrypt.h     |  62 ++++++++++++++++
 include/uapi/linux/fs.h     |   3 +-
 8 files changed, 285 insertions(+), 43 deletions(-)

diff --git a/fs/crypto/Kconfig b/fs/crypto/Kconfig
index 24ed99e2eca0..738368394a32 100644
--- a/fs/crypto/Kconfig
+++ b/fs/crypto/Kconfig
@@ -15,3 +15,9 @@ config FS_ENCRYPTION
 	  efficient since it avoids caching the encrypted and
 	  decrypted pages in the page cache.  Currently Ext4,
 	  F2FS and UBIFS make use of this feature.
+
+config FS_ENCRYPTION_INLINE_CRYPT
+	bool "Enable fscrypt to use inline crypto"
+	depends on FS_ENCRYPTION && BLK_INLINE_ENCRYPTION
+	help
+	  Enables fscrypt to use inline crypto hardware if available.
diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
index b46021ebde85..0e16189e1679 100644
--- a/fs/crypto/bio.c
+++ b/fs/crypto/bio.c
@@ -24,6 +24,9 @@
 #include <linux/module.h>
 #include <linux/bio.h>
 #include <linux/namei.h>
+#include <linux/keyslot-manager.h>
+#include <linux/blkdev.h>
+#include <crypto/algapi.h>
 #include "fscrypt_private.h"
 
 static void __fscrypt_decrypt_bio(struct bio *bio, bool done)
@@ -34,7 +37,7 @@ static void __fscrypt_decrypt_bio(struct bio *bio, bool done)
 	bio_for_each_segment_all(bv, bio, iter_all) {
 		struct page *page = bv->bv_page;
 		int ret = fscrypt_decrypt_page(page->mapping->host, page,
-				PAGE_SIZE, 0, page->index);
+					       PAGE_SIZE, 0, page->index);
 
 		if (ret)
 			SetPageError(page);
@@ -94,29 +97,33 @@ EXPORT_SYMBOL(fscrypt_pullback_bio_page);
 int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 				sector_t pblk, unsigned int len)
 {
-	struct fscrypt_ctx *ctx;
+	struct fscrypt_ctx *ctx = NULL;
 	struct page *ciphertext_page = NULL;
 	struct bio *bio;
 	int ret, err = 0;
 
 	BUG_ON(inode->i_sb->s_blocksize != PAGE_SIZE);
 
-	ctx = fscrypt_get_ctx(GFP_NOFS);
-	if (IS_ERR(ctx))
-		return PTR_ERR(ctx);
+	if (!fscrypt_inode_is_inline_crypted(inode)) {
+		ctx = fscrypt_get_ctx(GFP_NOFS);
+		if (IS_ERR(ctx))
+			return PTR_ERR(ctx);
 
-	ciphertext_page = fscrypt_alloc_bounce_page(ctx, GFP_NOWAIT);
-	if (IS_ERR(ciphertext_page)) {
-		err = PTR_ERR(ciphertext_page);
-		goto errout;
+		ciphertext_page = fscrypt_alloc_bounce_page(ctx, GFP_NOWAIT);
+		if (IS_ERR(ciphertext_page)) {
+			err = PTR_ERR(ciphertext_page);
+			goto errout;
+		}
 	}
 
 	while (len--) {
-		err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk,
+		if (!fscrypt_inode_is_inline_crypted(inode)) {
+			err = fscrypt_do_page_crypto(inode, FS_ENCRYPT, lblk,
 					     ZERO_PAGE(0), ciphertext_page,
 					     PAGE_SIZE, 0, GFP_NOFS);
-		if (err)
-			goto errout;
+			if (err)
+				goto errout;
+		}
 
 		bio = bio_alloc(GFP_NOWAIT, 1);
 		if (!bio) {
@@ -127,8 +134,14 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 		bio->bi_iter.bi_sector =
 			pblk << (inode->i_sb->s_blocksize_bits - 9);
 		bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
-		ret = bio_add_page(bio, ciphertext_page,
-					inode->i_sb->s_blocksize, 0);
+		if (!fscrypt_inode_is_inline_crypted(inode)) {
+			ret = bio_add_page(bio, ciphertext_page,
+						inode->i_sb->s_blocksize, 0);
+		} else {
+			ret = bio_add_page(bio, ZERO_PAGE(0),
+						inode->i_sb->s_blocksize, 0);
+		}
+
 		if (ret != inode->i_sb->s_blocksize) {
 			/* should never happen! */
 			WARN_ON(1);
@@ -136,9 +149,12 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 			err = -EIO;
 			goto errout;
 		}
-		err = submit_bio_wait(bio);
-		if (err == 0 && bio->bi_status)
-			err = -EIO;
+		err = fscrypt_set_bio_crypt_ctx(inode, bio, pblk);
+		if (!err) {
+			err = submit_bio_wait(bio);
+			if (err == 0 && bio->bi_status)
+				err = -EIO;
+		}
 		bio_put(bio);
 		if (err)
 			goto errout;
@@ -147,7 +163,93 @@ int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 	}
 	err = 0;
 errout:
-	fscrypt_release_ctx(ctx);
+	if (!fscrypt_inode_is_inline_crypted(inode))
+		fscrypt_release_ctx(ctx);
 	return err;
 }
 EXPORT_SYMBOL(fscrypt_zeroout_range);
+
+#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
+static enum blk_crypt_mode_num
+get_blk_crypto_alg_for_fscryptalg(u8 fscrypt_alg)
+{
+	switch (fscrypt_alg) {
+	case FS_ENCRYPTION_MODE_AES_256_XTS:
+		return BLK_ENCRYPTION_MODE_AES_256_XTS;
+	default: return -EINVAL;
+	}
+}
+
+int fscrypt_set_bio_crypt_ctx(const struct inode *inode,
+				 struct bio *bio, u64 data_unit_num)
+{
+	struct fscrypt_info *ci = inode->i_crypt_info;
+
+	/* If inode is not inline encrypted, nothing to do. */
+	if (!fscrypt_inode_is_inline_crypted(inode))
+		return 0;
+
+	return bio_crypt_set_ctx(bio, ci->ci_master_key->mk_raw,
+			get_blk_crypto_alg_for_fscryptalg(ci->ci_data_mode),
+			data_unit_num,
+			inode->i_blkbits);
+}
+EXPORT_SYMBOL(fscrypt_set_bio_crypt_ctx);
+
+void fscrypt_unset_bio_crypt_ctx(struct bio *bio)
+{
+	bio_crypt_free_ctx(bio);
+}
+EXPORT_SYMBOL(fscrypt_unset_bio_crypt_ctx);
+
+int fscrypt_evict_crypt_key(struct inode *inode)
+{
+	struct request_queue *q;
+	struct fscrypt_info *ci;
+
+	if (!inode)
+		return 0;
+
+	q = inode->i_sb->s_bdev->bd_queue;
+	ci = inode->i_crypt_info;
+
+	if (!q || !q->ksm || !ci ||
+	    !fscrypt_inode_is_inline_crypted(inode)) {
+		return 0;
+	}
+
+	return keyslot_manager_evict_key(q->ksm,
+					 ci->ci_master_key->mk_raw,
+					 get_blk_crypto_alg_for_fscryptalg(
+						ci->ci_data_mode),
+					 1 << inode->i_blkbits);
+}
+EXPORT_SYMBOL(fscrypt_evict_crypt_key);
+
+bool fscrypt_inode_crypt_mergeable(const struct inode *inode_1,
+				   const struct inode *inode_2)
+{
+	struct fscrypt_info *ci_1, *ci_2;
+	bool enc_1 = fscrypt_inode_is_inline_crypted(inode_1);
+	bool enc_2 = fscrypt_inode_is_inline_crypted(inode_2);
+
+	if (enc_1 != enc_2)
+		return false;
+
+	if (!enc_1)
+		return true;
+
+	if (inode_1 == inode_2)
+		return true;
+
+	ci_1 = inode_1->i_crypt_info;
+	ci_2 = inode_2->i_crypt_info;
+
+	return ci_1->ci_data_mode == ci_2->ci_data_mode &&
+	       crypto_memneq(ci_1->ci_master_key->mk_raw,
+			     ci_2->ci_master_key->mk_raw,
+			     ci_1->ci_master_key->mk_mode->keysize) == 0;
+}
+EXPORT_SYMBOL(fscrypt_inode_crypt_mergeable);
+
+#endif /* FS_ENCRYPTION_INLINE_CRYPT */
diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index 335a362ee446..58a01889fac7 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -302,6 +302,10 @@ int fscrypt_decrypt_page(const struct inode *inode, struct page *page,
 	if (!(inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES))
 		BUG_ON(!PageLocked(page));
 
+	/* If we have HW encryption, then this page is already decrypted */
+	if (fscrypt_inode_is_inline_crypted(inode))
+		return 0;
+
 	return fscrypt_do_page_crypto(inode, FS_DECRYPT, lblk_num, page, page,
 				      len, offs, GFP_NOFS);
 }
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index 7da276159593..67a8ca058996 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -49,6 +49,17 @@ struct fscrypt_symlink_data {
 	char encrypted_path[1];
 } __packed;
 
+/* Master key referenced by FS_POLICY_FLAG_DIRECT_KEY policy */
+struct fscrypt_master_key {
+	struct hlist_node mk_node;
+	refcount_t mk_refcount;
+	const struct fscrypt_mode *mk_mode;
+	struct crypto_skcipher *mk_ctfm;
+	u8 mk_descriptor[FS_KEY_DESCRIPTOR_SIZE];
+	u8 mk_raw[FS_MAX_KEY_SIZE];
+	struct super_block *mk_sb;
+};
+
 /*
  * fscrypt_info - the "encryption key" for an inode
  *
diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c
index dcd91a3fbe49..3a3b27b99706 100644
--- a/fs/crypto/keyinfo.c
+++ b/fs/crypto/keyinfo.c
@@ -25,6 +25,21 @@ static struct crypto_shash *essiv_hash_tfm;
 static DEFINE_HASHTABLE(fscrypt_master_keys, 6); /* 6 bits = 64 buckets */
 static DEFINE_SPINLOCK(fscrypt_master_keys_lock);
 
+#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
+static inline bool flags_inline_crypted(u8 flags,
+					const struct inode *inode)
+{
+	return inode && (flags & FS_POLICY_FLAGS_INLINE_CRYPT) &&
+	       S_ISREG(inode->i_mode);
+}
+#else
+static inline bool flags_inline_crypted(u8 flags,
+					const struct inode *inode)
+{
+	return false;
+}
+#endif /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
+
 /*
  * Key derivation function.  This generates the derived key by encrypting the
  * master key with AES-128-ECB using the inode's nonce as the AES key.
@@ -220,6 +235,9 @@ static int find_and_derive_key(const struct inode *inode,
 			memcpy(derived_key, payload->raw, mode->keysize);
 			err = 0;
 		}
+	} else if (flags_inline_crypted(ctx->flags, inode)) {
+		memcpy(derived_key, payload->raw, mode->keysize);
+		err = 0;
 	} else {
 		err = derive_key_aes(payload->raw, ctx, derived_key,
 				     mode->keysize);
@@ -269,16 +287,6 @@ allocate_skcipher_for_mode(struct fscrypt_mode *mode, const u8 *raw_key,
 	return ERR_PTR(err);
 }
 
-/* Master key referenced by FS_POLICY_FLAG_DIRECT_KEY policy */
-struct fscrypt_master_key {
-	struct hlist_node mk_node;
-	refcount_t mk_refcount;
-	const struct fscrypt_mode *mk_mode;
-	struct crypto_skcipher *mk_ctfm;
-	u8 mk_descriptor[FS_KEY_DESCRIPTOR_SIZE];
-	u8 mk_raw[FS_MAX_KEY_SIZE];
-};
-
 static void free_master_key(struct fscrypt_master_key *mk)
 {
 	if (mk) {
@@ -287,13 +295,15 @@ static void free_master_key(struct fscrypt_master_key *mk)
 	}
 }
 
-static void put_master_key(struct fscrypt_master_key *mk)
+static void put_master_key(struct fscrypt_master_key *mk,
+			   struct inode *inode)
 {
 	if (!refcount_dec_and_lock(&mk->mk_refcount, &fscrypt_master_keys_lock))
 		return;
 	hash_del(&mk->mk_node);
 	spin_unlock(&fscrypt_master_keys_lock);
 
+	fscrypt_evict_crypt_key(inode);
 	free_master_key(mk);
 }
 
@@ -306,7 +316,9 @@ static void put_master_key(struct fscrypt_master_key *mk)
 static struct fscrypt_master_key *
 find_or_insert_master_key(struct fscrypt_master_key *to_insert,
 			  const u8 *raw_key, const struct fscrypt_mode *mode,
-			  const struct fscrypt_info *ci)
+			  const struct fscrypt_info *ci,
+			  bool should_have_ctfm,
+			  struct super_block *sb)
 {
 	unsigned long hash_key;
 	struct fscrypt_master_key *mk;
@@ -329,6 +341,10 @@ find_or_insert_master_key(struct fscrypt_master_key *to_insert,
 			continue;
 		if (crypto_memneq(raw_key, mk->mk_raw, mode->keysize))
 			continue;
+		if (should_have_ctfm != (bool)mk->mk_ctfm)
+			continue;
+		if (sb != mk->mk_sb)
+			continue;
 		/* using existing tfm with same (descriptor, mode, raw_key) */
 		refcount_inc(&mk->mk_refcount);
 		spin_unlock(&fscrypt_master_keys_lock);
@@ -348,9 +364,11 @@ fscrypt_get_master_key(const struct fscrypt_info *ci, struct fscrypt_mode *mode,
 {
 	struct fscrypt_master_key *mk;
 	int err;
+	bool inline_crypted = flags_inline_crypted(ci->ci_flags, inode);
 
 	/* Is there already a tfm for this key? */
-	mk = find_or_insert_master_key(NULL, raw_key, mode, ci);
+	mk = find_or_insert_master_key(NULL, raw_key, mode, ci, !inline_crypted,
+				       inode->i_sb);
 	if (mk)
 		return mk;
 
@@ -360,17 +378,21 @@ fscrypt_get_master_key(const struct fscrypt_info *ci, struct fscrypt_mode *mode,
 		return ERR_PTR(-ENOMEM);
 	refcount_set(&mk->mk_refcount, 1);
 	mk->mk_mode = mode;
-	mk->mk_ctfm = allocate_skcipher_for_mode(mode, raw_key, inode);
-	if (IS_ERR(mk->mk_ctfm)) {
-		err = PTR_ERR(mk->mk_ctfm);
-		mk->mk_ctfm = NULL;
-		goto err_free_mk;
+	if (!inline_crypted) {
+		mk->mk_ctfm = allocate_skcipher_for_mode(mode, raw_key, inode);
+		if (IS_ERR(mk->mk_ctfm)) {
+			err = PTR_ERR(mk->mk_ctfm);
+			mk->mk_ctfm = NULL;
+			goto err_free_mk;
+		}
 	}
 	memcpy(mk->mk_descriptor, ci->ci_master_key_descriptor,
 	       FS_KEY_DESCRIPTOR_SIZE);
 	memcpy(mk->mk_raw, raw_key, mode->keysize);
+	mk->mk_sb = inode->i_sb;
 
-	return find_or_insert_master_key(mk, raw_key, mode, ci);
+	return find_or_insert_master_key(mk, raw_key, mode, ci, !inline_crypted,
+					 inode->i_sb);
 
 err_free_mk:
 	free_master_key(mk);
@@ -456,7 +478,8 @@ static int setup_crypto_transform(struct fscrypt_info *ci,
 	struct crypto_skcipher *ctfm;
 	int err;
 
-	if (ci->ci_flags & FS_POLICY_FLAG_DIRECT_KEY) {
+	if ((ci->ci_flags & FS_POLICY_FLAG_DIRECT_KEY) ||
+	    flags_inline_crypted(ci->ci_flags, inode)) {
 		mk = fscrypt_get_master_key(ci, mode, raw_key, inode);
 		if (IS_ERR(mk))
 			return PTR_ERR(mk);
@@ -486,13 +509,13 @@ static int setup_crypto_transform(struct fscrypt_info *ci,
 	return 0;
 }
 
-static void put_crypt_info(struct fscrypt_info *ci)
+static void put_crypt_info(struct fscrypt_info *ci, struct inode *inode)
 {
 	if (!ci)
 		return;
 
 	if (ci->ci_master_key) {
-		put_master_key(ci->ci_master_key);
+		put_master_key(ci->ci_master_key, inode);
 	} else {
 		crypto_free_skcipher(ci->ci_ctfm);
 		crypto_free_cipher(ci->ci_essiv_tfm);
@@ -577,7 +600,7 @@ int fscrypt_get_encryption_info(struct inode *inode)
 out:
 	if (res == -ENOKEY)
 		res = 0;
-	put_crypt_info(crypt_info);
+	put_crypt_info(crypt_info, NULL);
 	kzfree(raw_key);
 	return res;
 }
@@ -591,7 +614,7 @@ EXPORT_SYMBOL(fscrypt_get_encryption_info);
  */
 void fscrypt_put_encryption_info(struct inode *inode)
 {
-	put_crypt_info(inode->i_crypt_info);
+	put_crypt_info(inode->i_crypt_info, inode);
 	inode->i_crypt_info = NULL;
 }
 EXPORT_SYMBOL(fscrypt_put_encryption_info);
@@ -610,3 +633,26 @@ void fscrypt_free_inode(struct inode *inode)
 	}
 }
 EXPORT_SYMBOL(fscrypt_free_inode);
+
+#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
+bool fscrypt_inode_is_inline_crypted(const struct inode *inode)
+{
+	struct fscrypt_info *ci;
+
+	if (!inode)
+		return false;
+	ci = inode->i_crypt_info;
+
+	return ci && flags_inline_crypted(ci->ci_flags, inode);
+}
+EXPORT_SYMBOL(fscrypt_inode_is_inline_crypted);
+
+#endif /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
+
+bool fscrypt_needs_fs_layer_crypto(const struct inode *inode)
+{
+	return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode) &&
+	       !fscrypt_inode_is_inline_crypted(inode);
+}
+EXPORT_SYMBOL(fscrypt_needs_fs_layer_crypto);
+
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index d536889ac31b..7bcf5cc0d20d 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -36,6 +36,7 @@ static int create_encryption_context_from_policy(struct inode *inode,
 	struct fscrypt_context ctx;
 
 	ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
+
 	memcpy(ctx.master_key_descriptor, policy->master_key_descriptor,
 					FS_KEY_DESCRIPTOR_SIZE);
 
@@ -46,8 +47,17 @@ static int create_encryption_context_from_policy(struct inode *inode,
 	if (policy->flags & ~FS_POLICY_FLAGS_VALID)
 		return -EINVAL;
 
+	/*
+	 * TODO: expose inline encryption via some toggleable knob
+	 * instead of as a policy?
+	 */
+	if (!inode->i_sb->s_cop->inline_crypt_supp &&
+	    (policy->flags & FS_POLICY_FLAGS_INLINE_CRYPT))
+		return -EINVAL;
+
 	ctx.contents_encryption_mode = policy->contents_encryption_mode;
 	ctx.filenames_encryption_mode = policy->filenames_encryption_mode;
+
 	ctx.flags = policy->flags;
 	BUILD_BUG_ON(sizeof(ctx.nonce) != FS_KEY_DERIVATION_NONCE_SIZE);
 	get_random_bytes(ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE);
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index f7680ef1abd2..ea205aa8a24a 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -61,6 +61,7 @@ struct fscrypt_operations {
 	bool (*dummy_context)(struct inode *);
 	bool (*empty_dir)(struct inode *);
 	unsigned int max_namelen;
+	bool inline_crypt_supp;
 };
 
 struct fscrypt_ctx {
@@ -129,6 +130,23 @@ extern int fscrypt_inherit_context(struct inode *, struct inode *,
 extern int fscrypt_get_encryption_info(struct inode *);
 extern void fscrypt_put_encryption_info(struct inode *);
 extern void fscrypt_free_inode(struct inode *);
+extern bool fscrypt_needs_fs_layer_crypto(const struct inode *inode);
+
+#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
+extern bool fscrypt_inode_is_inline_crypted(const struct inode *inode);
+extern bool fscrypt_inode_crypt_mergeable(const struct inode *inode_1,
+					  const struct inode *inode_2);
+#else
+static inline bool fscrypt_inode_is_inline_crypted(const struct inode *inode)
+{
+	return false;
+}
+static inline bool fscrypt_inode_crypt_mergeable(const struct inode *inode_1,
+						 const struct inode *inode_2)
+{
+	return true;
+}
+#endif /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */
 
 /* fname.c */
 extern int fscrypt_setup_filename(struct inode *, const struct qstr *,
@@ -226,6 +244,25 @@ extern void fscrypt_enqueue_decrypt_bio(struct fscrypt_ctx *ctx,
 extern void fscrypt_pullback_bio_page(struct page **, bool);
 extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t,
 				 unsigned int);
+#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
+extern int fscrypt_set_bio_crypt_ctx(const struct inode *inode,
+				     struct bio *bio, u64 data_unit_num);
+extern void fscrypt_unset_bio_crypt_ctx(struct bio *bio);
+extern int fscrypt_evict_crypt_key(struct inode *inode);
+#else
+static inline int fscrypt_set_bio_crypt_ctx(const struct inode *inode,
+					    struct bio *bio, u64 data_unit_num)
+{
+	return 0;
+}
+
+static inline void fscrypt_unset_bio_crypt_ctx(struct bio *bio) { }
+
+static inline int fscrypt_evict_crypt_key(struct inode *inode)
+{
+	return 0;
+}
+#endif
 
 /* hooks.c */
 extern int fscrypt_file_open(struct inode *inode, struct file *filp);
@@ -351,6 +388,17 @@ static inline void fscrypt_free_inode(struct inode *inode)
 {
 }
 
+static inline bool fscrypt_inode_is_inline_crypted(const struct inode *inode)
+{
+	return false;
+}
+
+static inline bool fscrypt_inode_crypt_mergeable(const struct inode *inode_1,
+						 const struct inode *inode_2)
+{
+	return true;
+}
+
  /* fname.c */
 static inline int fscrypt_setup_filename(struct inode *dir,
 					 const struct qstr *iname,
@@ -421,6 +469,20 @@ static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
 	return -EOPNOTSUPP;
 }
 
+static inline int fscrypt_set_bio_crypt_ctx(const struct inode *inode,
+					    struct bio *bio,
+					    u64 data_unit_num)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void fscrypt_unset_bio_crypt_ctx(struct bio *bio) { }
+
+static inline int fscrypt_evict_crypt_key(struct inode *inode)
+{
+	return 0;
+}
+
 /* hooks.c */
 
 static inline int fscrypt_file_open(struct inode *inode, struct file *filp)
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 59c71fa8c553..ec5a9913886c 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -224,7 +224,8 @@ struct fsxattr {
 #define FS_POLICY_FLAGS_PAD_32		0x03
 #define FS_POLICY_FLAGS_PAD_MASK	0x03
 #define FS_POLICY_FLAG_DIRECT_KEY	0x04	/* use master key directly */
-#define FS_POLICY_FLAGS_VALID		0x07
+#define FS_POLICY_FLAGS_INLINE_CRYPT	0x08
+#define FS_POLICY_FLAGS_VALID		0x0F
 
 /* Encryption algorithms */
 #define FS_ENCRYPTION_MODE_INVALID		0
-- 
2.22.0.410.gd8fdbe21b5-goog



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[f2fs-dev] [PATCH 8/8] f2fs: Wire up f2fs to use inline encryption via fscrypt

[Satya Tangirala via Linux-f2fs-devel]

Signed-off-by: Satya Tangirala <satyat@google.com>
---
 fs/f2fs/data.c  | 83 +++++++++++++++++++++++++++++++++++++++++++++----
 fs/f2fs/super.c | 13 ++++----
 2 files changed, 84 insertions(+), 12 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index eda4181d2092..6fa947725fc2 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -142,6 +142,8 @@ static bool f2fs_bio_post_read_required(struct bio *bio)
 
 static void f2fs_read_end_io(struct bio *bio)
 {
+	fscrypt_unset_bio_crypt_ctx(bio);
+
 	if (time_to_inject(F2FS_P_SB(bio_first_page_all(bio)),
 						FAULT_READ_IO)) {
 		f2fs_show_injection_info(FAULT_READ_IO);
@@ -165,6 +167,8 @@ static void f2fs_write_end_io(struct bio *bio)
 	struct bio_vec *bvec;
 	struct bvec_iter_all iter_all;
 
+	fscrypt_unset_bio_crypt_ctx(bio);
+
 	if (time_to_inject(sbi, FAULT_WRITE_IO)) {
 		f2fs_show_injection_info(FAULT_WRITE_IO);
 		bio->bi_status = BLK_STS_IOERR;
@@ -282,9 +286,18 @@ static struct bio *__bio_alloc(struct f2fs_sb_info *sbi, block_t blk_addr,
 	return bio;
 }
 
+static inline u64 inline_crypt_dun(struct inode *inode, pgoff_t offset)
+{
+	return (((u64)inode->i_ino) << 32) | lower_32_bits(offset);
+}
+
 static inline void __submit_bio(struct f2fs_sb_info *sbi,
 				struct bio *bio, enum page_type type)
 {
+	struct page *page;
+	struct inode *inode;
+	int err = 0;
+
 	if (!is_read_io(bio_op(bio))) {
 		unsigned int start;
 
@@ -326,7 +339,22 @@ static inline void __submit_bio(struct f2fs_sb_info *sbi,
 		trace_f2fs_submit_read_bio(sbi->sb, type, bio);
 	else
 		trace_f2fs_submit_write_bio(sbi->sb, type, bio);
-	submit_bio(bio);
+
+	if (bio_has_data(bio)) {
+		page = bio_page(bio);
+		if (page && page->mapping && page->mapping->host) {
+			inode = page->mapping->host;
+			err = fscrypt_set_bio_crypt_ctx(inode, bio,
+						inline_crypt_dun(inode,
+								 page->index));
+		}
+	}
+	if (err) {
+		bio->bi_status = BLK_STS_IOERR;
+		bio_endio(bio);
+	} else {
+		submit_bio(bio);
+	}
 }
 
 static void __submit_merged_bio(struct f2fs_bio_info *io)
@@ -487,6 +515,9 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
 	enum page_type btype = PAGE_TYPE_OF_BIO(fio->type);
 	struct f2fs_bio_info *io = sbi->write_io[btype] + fio->temp;
 	struct page *bio_page;
+	struct inode *fio_inode, *bio_inode;
+	struct page *first_page;
+	u64 next_dun = 0;
 
 	f2fs_bug_on(sbi, is_read_io(fio->op));
 
@@ -513,10 +544,28 @@ void f2fs_submit_page_write(struct f2fs_io_info *fio)
 
 	inc_page_count(sbi, WB_DATA_TYPE(bio_page));
 
+	fio_inode = fio->page->mapping->host;
+	bio_inode = NULL;
+	first_page = NULL;
+	next_dun = 0;
+	if (io->bio && bio_page(io->bio)->mapping) {
+		first_page = bio_page(io->bio);
+		bio_inode = first_page->mapping->host;
+		if (fscrypt_inode_is_inline_crypted(bio_inode)) {
+			next_dun = inline_crypt_dun(bio_inode,
+						    first_page->index) +
+				   (io->bio->bi_iter.bi_size >> PAGE_SHIFT);
+		}
+	}
 	if (io->bio && (io->last_block_in_bio != fio->new_blkaddr - 1 ||
 	    (io->fio.op != fio->op || io->fio.op_flags != fio->op_flags) ||
-			!__same_bdev(sbi, fio->new_blkaddr, io->bio)))
+			!__same_bdev(sbi, fio->new_blkaddr, io->bio) ||
+			!fscrypt_inode_crypt_mergeable(bio_inode, fio_inode) ||
+			(fscrypt_inode_is_inline_crypted(bio_inode) &&
+			 next_dun != inline_crypt_dun(fio_inode,
+						  fio->page->index))))
 		__submit_merged_bio(io);
+
 alloc_new:
 	if (io->bio == NULL) {
 		if ((fio->type == DATA || fio->type == NODE) &&
@@ -568,8 +617,9 @@ static struct bio *f2fs_grab_read_bio(struct inode *inode, block_t blkaddr,
 	bio->bi_end_io = f2fs_read_end_io;
 	bio_set_op_attrs(bio, REQ_OP_READ, op_flag);
 
-	if (f2fs_encrypted_file(inode))
+	if (fscrypt_needs_fs_layer_crypto(inode))
 		post_read_steps |= 1 << STEP_DECRYPT;
+
 	if (post_read_steps) {
 		ctx = mempool_alloc(bio_post_read_ctx_pool, GFP_NOFS);
 		if (!ctx) {
@@ -1519,6 +1569,7 @@ static int f2fs_read_single_page(struct inode *inode, struct page *page,
 					struct f2fs_map_blocks *map,
 					struct bio **bio_ret,
 					sector_t *last_block_in_bio,
+					u64 *next_dun,
 					bool is_readahead)
 {
 	struct bio *bio = *bio_ret;
@@ -1592,6 +1643,13 @@ static int f2fs_read_single_page(struct inode *inode, struct page *page,
 		__submit_bio(F2FS_I_SB(inode), bio, DATA);
 		bio = NULL;
 	}
+
+	if (bio && fscrypt_inode_is_inline_crypted(inode) &&
+	    *next_dun != inline_crypt_dun(inode, page->index)) {
+		__submit_bio(F2FS_I_SB(inode), bio, DATA);
+		bio = NULL;
+	}
+
 	if (bio == NULL) {
 		bio = f2fs_grab_read_bio(inode, block_nr, nr_pages,
 				is_readahead ? REQ_RAHEAD : 0);
@@ -1611,6 +1669,9 @@ static int f2fs_read_single_page(struct inode *inode, struct page *page,
 	if (bio_add_page(bio, page, blocksize, 0) < blocksize)
 		goto submit_and_realloc;
 
+	if (fscrypt_inode_is_inline_crypted(inode))
+		*next_dun = inline_crypt_dun(inode, page->index) + 1;
+
 	inc_page_count(F2FS_I_SB(inode), F2FS_RD_DATA);
 	ClearPageError(page);
 	*last_block_in_bio = block_nr;
@@ -1644,6 +1705,7 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
 	struct inode *inode = mapping->host;
 	struct f2fs_map_blocks map;
 	int ret = 0;
+	u64 next_dun = 0;
 
 	map.m_pblk = 0;
 	map.m_lblk = 0;
@@ -1667,7 +1729,8 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
 		}
 
 		ret = f2fs_read_single_page(inode, page, nr_pages, &map, &bio,
-					&last_block_in_bio, is_readahead);
+					&last_block_in_bio, &next_dun,
+					is_readahead);
 		if (ret) {
 			SetPageError(page);
 			zero_user_segment(page, 0, PAGE_SIZE);
@@ -1720,7 +1783,7 @@ static int encrypt_one_page(struct f2fs_io_info *fio)
 	struct page *mpage;
 	gfp_t gfp_flags = GFP_NOFS;
 
-	if (!f2fs_encrypted_file(inode))
+	if (!fscrypt_needs_fs_layer_crypto(inode))
 		return 0;
 
 	/* wait for GCed page writeback via META_MAPPING */
@@ -1899,7 +1962,7 @@ int f2fs_do_write_data_page(struct f2fs_io_info *fio)
 			f2fs_unlock_op(fio->sbi);
 		err = f2fs_inplace_write_data(fio);
 		if (err) {
-			if (f2fs_encrypted_file(inode))
+			if (fscrypt_needs_fs_layer_crypto(inode))
 				fscrypt_pullback_bio_page(&fio->encrypted_page,
 									true);
 			if (PageWriteback(page))
@@ -2617,6 +2680,8 @@ static void f2fs_dio_end_io(struct bio *bio)
 {
 	struct f2fs_private_dio *dio = bio->bi_private;
 
+	fscrypt_unset_bio_crypt_ctx(bio);
+
 	dec_page_count(F2FS_I_SB(dio->inode),
 			dio->write ? F2FS_DIO_WRITE : F2FS_DIO_READ);
 
@@ -2633,12 +2698,18 @@ static void f2fs_dio_submit_bio(struct bio *bio, struct inode *inode,
 {
 	struct f2fs_private_dio *dio;
 	bool write = (bio_op(bio) == REQ_OP_WRITE);
+	u64 data_unit_num = inline_crypt_dun(inode, file_offset >> PAGE_SHIFT);
 
 	dio = f2fs_kzalloc(F2FS_I_SB(inode),
 			sizeof(struct f2fs_private_dio), GFP_NOFS);
 	if (!dio)
 		goto out;
 
+	if (fscrypt_set_bio_crypt_ctx(inode, bio, data_unit_num) != 0) {
+		kvfree(dio);
+		goto out;
+	}
+
 	dio->inode = inode;
 	dio->orig_end_io = bio->bi_end_io;
 	dio->orig_private = bio->bi_private;
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 6b959bbb336a..2a7b3bae98aa 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2223,12 +2223,13 @@ static bool f2fs_dummy_context(struct inode *inode)
 }
 
 static const struct fscrypt_operations f2fs_cryptops = {
-	.key_prefix	= "f2fs:",
-	.get_context	= f2fs_get_context,
-	.set_context	= f2fs_set_context,
-	.dummy_context	= f2fs_dummy_context,
-	.empty_dir	= f2fs_empty_dir,
-	.max_namelen	= F2FS_NAME_LEN,
+	.key_prefix		= "f2fs:",
+	.get_context		= f2fs_get_context,
+	.set_context		= f2fs_set_context,
+	.dummy_context		= f2fs_dummy_context,
+	.empty_dir		= f2fs_empty_dir,
+	.max_namelen		= F2FS_NAME_LEN,
+	.inline_crypt_supp	= true,
 };
 #endif
 
-- 
2.22.0.410.gd8fdbe21b5-goog



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Re: [f2fs-dev] [PATCH 3/8] block: blk-crypto for Inline Encryption

[Randy Dunlap]

Hi,

Documentation nits, typos. questions...

On 7/10/19 3:56 PM, Satya Tangirala wrote:
> diff --git a/Documentation/block/inline-encryption.txt b/Documentation/block/inline-encryption.txt
> new file mode 100644
> index 000000000000..96a7983a117d
> --- /dev/null
> +++ b/Documentation/block/inline-encryption.txt
> @@ -0,0 +1,185 @@
> +BLK-CRYPTO and KEYSLOT MANAGER
> +===========================
> +
> +CONTENTS
> +1. Objective
> +2. Constraints and notes
> +3. Design
> +4. Blk-crypto
> + 4-1 What does blk-crypto do on bio submission
> +5. Layered Devices
> +6. Future optimizations for layered devices
> +
> +1. Objective
> +============
> +
> +We want to support inline encryption (IE) in the kernel.
> +To allow for testing, we also want a software fallback when actual
> +IE hardware is absent. We also want IE to work with layered devices
> +like dm and loopback (i.e. we want to be able to use the IE hardware
> +of the underlying devices if present, or else fall back to software
> +en/decryption).
> +
> +
> +2. Constraints and notes
> +========================
> +
> +1) IE hardware have a limited number of “keyslots” that can be programmed
> +with an encryption context (key, algorithm, data unit size, etc.) at any time.
> +One can specify a keyslot in a data request made to the device, and the
> +device will en/decrypt the data using the encryption context programmed into
> +that specified keyslot. When possible, we want to make multiple requests with
> +the same encryption context share the same keyslot.
> +
> +2) We need a way for filesystems to specify an encryption context to use for
> +en/decrypting a struct bio, and a device driver (like UFS) needs to be able
> +to use that encryption context when it processes the bio.
> +
> +3) We need a way for device drivers to expose their capabilities in a unified
> +way to the upper layers.
> +
> +
> +3. Design
> +=========
> +
> +We add a struct bio_crypt_context to struct bio that can represent an

         is this   bi_crypt_context ??

> +encryption context, because we need to able to pass this encryption context

                                       to be able

> +from the FS layer to the device driver to act upon.
> +
> +While IE hardware works on the notion of keyslots, the FS layer has no
> +knowledge of keyslots - it simply wants to specify an encryption context to
> +use while en/decrypting a bio.
> +
> +We introduce a keyslot manager (KSM) that handles the translation from
> +encryption contexts specified by the FS to keyslots on the IE hardware.
> +This KSM also serves as the way IE hardware can expose their capabilities to
> +upper layers. The generic mode of operation is: each device driver that wants
> +to support IE will construct a KSM and set it up in its struct request_queue.
> +Upper layers that want to use IE on this device can then use this KSM in
> +the device’s struct request_queue to translate an encryption context into
> +a keyslot. The presence of the KSM in the request queue shall be used to mean
> +that the device supports IE.
> +
> +On the device driver end of the interface, the device driver needs to tell the
> +KSM how to actually manipulate the IE hardware in the device to do things like
> +programming the crypto key into the IE hardware into a particular keyslot. All
> +this is achieved through the struct keyslot_mgmt_ll_ops that the device driver
> +passes to the KSM when creating it.
> +
> +It uses refcounts to track which keyslots are idle (either they have no
> +encryption context programmed, or there are no in flight struct bios

                                                  in-flight

> +referencing that keyslot). When a new encryption context needs a keyslot, it
> +tries to find a keyslot that has already been programmed with the same
> +encryption context, and if there is no such keyslot, it evicts the least
> +recently used idle keyslot and programs the new encryption context into that
> +one. If no idle keyslots are available, then the caller will sleep until there
> +is at least one.
> +
> +
> +4. Blk-crypto
> +=============
> +
> +The above is sufficient for simple cases, but does not work if there is a
> +need for a software fallback, or if we are want to use IE with layered devices.
> +To these ends, we introduce blk-crypto. Blk-crypto allows us to present a
> +unified view of encryption to the FS (so FS only needs to specify an
> +encryption context and not worry about keyslots at all), and blk-crypto can
> +decide whether to delegate the en/decryption to IE hardware or to software
> +(i.e. to the kernel crypto API). Blk-crypto maintains an internal KSM that
> +serves as the software fallback to the kernel crypto API.
> +
> +Blk-crypto needs to ensure that the encryption context is programmed into the
> +"correct" keyslot manager for IE. If a bio is submitted to a layered device
> +that eventually passes the bio down to a device that really does support IE, we
> +want the encryption context to be programmed into a keyslot for the KSM of the
> +device with IE support. However, blk-crypto does not know a priori whether a
> +particular device is the final device in the layering structure for a bio or
> +not. So in the case that a particular device does not support IE, since it is
> +possibly the final destination device for the bio, if the bio requires
> +encryption (i.e. the bio is doing a write operation), blk-crypto must fallback
> +to software *before* sending the bio to the device.
> +
> +Blk-crypto ensures that
> +1) The bio’s encryption context is programmed into a keyslot in the KSM of the
> +request queue that the bio is being submitted to (or the software fallback KSM
> +if the request queue doesn’t have a KSM), and that the processing_ksm in the
> +bi_crypt_context is set to this KSM
> +
> +2) That the bio has its own individual reference to the keyslot in this KSM.
> +Once the bio passes through blk-crypto, its encryption context is programmed
> +in some KSM. The “its own individual reference to the keyslot” ensures that
> +keyslots can be released by each bio independently of other bios while ensuring
> +that the bio has a valid reference to the keyslot when, for e.g., the software
> +fallback KSM in blk-crypto performs crypto for on the device’s behalf. The
> +individual references are ensured by increasing the refcount for the keyslot in
> +the processing_ksm when a bio with a programmed encryption context is cloned.
> +
> +
> +4-1. What blk-crypto does on bio submission
> +-------------------------------------------
> +
> +Case 1: blk-crypto is given a bio with only an encryption context that hasn’t
> +been programmed into any keyslot in any KSM (for e.g. a bio from the FS). In
> +this case, blk-crypto will program the encryption context into the KSM of the
> +request queue the bio is being submitted to (and if this KSM does not exist,
> +then it will program it into blk-crypto’s internal KSM for software fallback).
> +The KSM that this encryption context was programmed into is stored as the
> +processing_ksm in the bio’s bi_crypt_context.
> +
> +Case 2: blk-crypto is given a bio whose encryption context has already been
> +programmed into a keyslot in the *software fallback KSM*. In this case,
> +blk-crypto does nothing; it treats the bio as not having specified an
> +encryption context. Note that we cannot do what we will do in Case 3 here

                       Note that we cannot do here what we will do in Case 3

> +because we would have already encrypted the bio in software by this point.
> +
> +Case 3: blk-crypto is given a bio whose encryption context has already been
> +programmed into a keyslot in some KSM (that is *not* the software fallback
> +KSM). In this case, blk-crypto first releases that keyslot from that KSM and
> +then treats the bio as in Case 1.
> +
> +This way, when a device driver is processing a bio, it can be sure that
> +the bio’s encryption context has been programmed into some KSM (either the
> +device driver’s request queue’s KSM, or blk-crypto’s software fallback KSM).
> +It then simply needs to check if the bio’s processing_ksm is the device’s
> +request queue’s KSM. If so, then it should proceed with IE. If not, it should
> +simply do nothing with respect to crypto, because some other KSM (perhaps the
> +blk-crypto software fallback KSM) is handling the en/decryption.
> +
> +Blk-crypto will release the keyslot that is being held by the bio (and also
> +decrypt it if the bio is using the software fallback KSM) once
> +bio_remaining_done returns true for the bio.
> +
> +
> +5. Layered Devices
> +==================
> +
> +Layered devices that wish to support IE need to create their own keyslot
> +manager for their request queue, and expose whatever functionality they choose.
> +When a layered device wants to pass a bio to another layer (either by
> +resubmitting the same bio, or by submitting a clone), it doesn’t need to do
> +anything special because the bio (or the clone) will once again pass through
> +blk-crypto, which will work as described in Case 3. If a layered device wants
> +for some reason to do the IO by itself instead of passing it on to a child
> +device, but it also chose to expose IE capabilities by setting up a KSM in its
> +request queue, it is then responsible for en/decrypting the data itself. In
> +such cases, the device can choose to call the blk-crypto function
> +blk_crypto_fallback_to_software (TODO: Not yet implemented), which will
> +cause the en/decryption to be done via software fallback.
> +
> +
> +6. Future Optimizations for layered devices
> +===========================================
> +
> +Creating a keyslot manager for the layered device uses up memory for each
> +keyslot, and in general, a layered device (like dm-linear) merely passes the
> +request on to a “child” device, so the keyslots in the layered device itself
> +might be completely unused. We can instead define a new type of KSM; the
> +“passthrough KSM”, that layered devices can use to let blk-crypto know that
> +this layered device *will* pass the bio to some child device (and hence
> +through blk-crypto again, at which point blk-crypto can program the encryption
> +context, instead of programming it into the layered device’s KSM). Again, if
> +the device “lies” and decides to do the IO itself instead of passing it on to
> +a child device, it is responsible for doing the en/decryption (and can choose
> +to call blk_crypto_fallback_to_software). Another use case for the
> +"passthrough KSM" is for IE devices that want to manage their own keyslots/do
> +not have a limited number of keyslots.


-- 
~Randy


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Re: [f2fs-dev] [PATCH 7/8] fscrypt: wire up fscrypt to use blk-crypto

[Eric Biggers]

Hi Satya,

On Wed, Jul 10, 2019 at 03:56:08PM -0700, Satya Tangirala wrote:
> Introduce fscrypt_set_bio_crypt_ctx for filesystems to call to set up
> encryption contexts in bios, and fscrypt_evict_crypt_key to evict
> the encryption context associated with an inode.
> 
> Inline encryption is controlled by a policy flag in the fscrypt_info
> in the inode, and filesystems may check if an inode should use inline
> encryption by calling fscrypt_inode_is_inline_crypted. Files can be marked
> as inline encrypted from userspace by appropriately modifying the flags
> (OR-ing FS_POLICY_FLAGS_INLINE_ENCRYPTION to it) in the fscrypt_policy
> passed to fscrypt_ioctl_set_policy.
> 
> To test inline encryption with the fscrypt dummy context, add
> ctx.flags |= FS_POLICY_FLAGS_INLINE_ENCRYPTION
> when setting up the dummy context in fs/crypto/keyinfo.c.
> 
> Note that blk-crypto will fall back to software en/decryption in the
> absence of inline crypto hardware, so setting up the ctx.flags in the
> dummy context without inline crypto hardware serves as a test for
> the software fallback in blk-crypto.
> 
> Signed-off-by: Satya Tangirala <satyat@google.com>

Thanks for the new patches.  I implemented a ciphertext verification test for
this new encryption policy flag, using the framework for ciphertext verification
tests I added to xfstests a few months ago.  You can get it from here:
https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/xfstests-dev.git/log/?h=inline-encryption
If you build a kvm-xfstests test appliance from that branch, the test can be run
with 'kvm-xfstests -c f2fs generic/700'.

Or better: run 'kvm-xfstests -c ext4,f2fs -g encrypt' to run all fscrypt tests
on ext4 and f2fs, including that one.  I recommend adding that to the testing
you do, if you haven't already.  Note that this is separate from running
xfstests with the "fscrypt dummy context" as you mention in the commit message;
see the new documentation at
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/filesystems/fscrypt.rst#n653

I found a bug.  The test passes when CONFIG_FS_ENCRYPTION_INLINE_CRYPT=y, but
fails when CONFIG_FS_ENCRYPTION_INLINE_CRYPT=n, rather than being skipped.  This
is because the kernel incorrectly ignores the policy flag in the latter case and
produces the wrong ciphertext, rather than rejecting it in
FS_IOC_SET_ENCRYPTION_POLICY.  So that needs to be fixed.

> diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
> index 335a362ee446..58a01889fac7 100644
> --- a/fs/crypto/crypto.c
> +++ b/fs/crypto/crypto.c
> @@ -302,6 +302,10 @@ int fscrypt_decrypt_page(const struct inode *inode, struct page *page,
>  	if (!(inode->i_sb->s_cop->flags & FS_CFLG_OWN_PAGES))
>  		BUG_ON(!PageLocked(page));
>  
> +	/* If we have HW encryption, then this page is already decrypted */
> +	if (fscrypt_inode_is_inline_crypted(inode))
> +		return 0;
> +
>  	return fscrypt_do_page_crypto(inode, FS_DECRYPT, lblk_num, page, page,
>  				      len, offs, GFP_NOFS);
>  }

As I mentioned on v2, the purpose of this function is to decrypt the page.  The
filesystem also has to allocate a decryption context and schedule a workqueue
item specifically to call this -- only for it to be a no-op in this new case
this patch adds.  I think the more logical approach would be for the filesystem
to not call this at all if the inode is using inline encryption instead.

> +#ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT
> +bool fscrypt_inode_is_inline_crypted(const struct inode *inode)
> +{
> +	struct fscrypt_info *ci;
> +
> +	if (!inode)
> +		return false;
> +	ci = inode->i_crypt_info;
> +
> +	return ci && flags_inline_crypted(ci->ci_flags, inode);
> +}
> +EXPORT_SYMBOL(fscrypt_inode_is_inline_crypted);

What does it mean for the inode to be NULL here?

This also returns false whenever the inode's encryption key hasn't been set up,
even though the inode may use an encryption policy with the inline encryption
optimized flag set.  Why?  Also, because ->i_crypt_info is set locklessly, if
it's being dereferenced conditionally it needs to be loaded with READ_ONCE().

So I'm confused about exactly what this is trying to do, and the lack of a
kerneldoc comment doesn't help :-(

But AFAICS, this is only called if the encryption key is available.
So I think the following would be better:

bool fscrypt_inode_is_inline_crypted(const struct inode *inode)
{
	return flags_inline_crypted(inode->i_crypt_info->ci_flags, inode);
}

... or if it's also expected to handle unencrypted inodes,

bool fscrypt_inode_is_inline_crypted(const struct inode *inode)
{
	return IS_ENCRYPTED(inode) &&
	       flags_inline_crypted(inode->i_crypt_info->ci_flags, inode);
}

The problem with trying to be "safe" and check for NULL ->i_crypt_info is that
the fallback behavior this patch implements is to silently do the encryption
incorrectly.  I don't think that's a good idea.  If someone is incorrectly
calling this on an inode that hasn't had its key loaded yet, I'd much rather be
notified of the bug immediately and fix it.

> +
> +bool fscrypt_needs_fs_layer_crypto(const struct inode *inode)
> +{
> +	return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode) &&
> +	       !fscrypt_inode_is_inline_crypted(inode);
> +}
> +EXPORT_SYMBOL(fscrypt_needs_fs_layer_crypto);

Can you please add a kerneldoc comment for all new functions in fs/crypto/ that
are exported to filesystems?

> +	/*
> +	 * TODO: expose inline encryption via some toggleable knob
> +	 * instead of as a policy?
> +	 */
> +	if (!inode->i_sb->s_cop->inline_crypt_supp &&
> +	    (policy->flags & FS_POLICY_FLAGS_INLINE_CRYPT))
> +		return -EINVAL;
> +

This TODO doesn't make sense; the policy flag is fine.

I think the name of the flag is still confusing things.  It's not enabling
inline encryption per se (that's an implementation detail), but rather an
on-disk format that's better suited for inline encryption.

How about renaming the flag to FS_POLICY_FLAG_INLINECRYPT_OPTIMIZED, like I
suggested on v2?

- Eric


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Re: [f2fs-dev] [PATCH 3/8] block: blk-crypto for Inline Encryption

[Eric Biggers]

Hi Satya, here's yet another round of comments.  I'd really like for
people who are experts in the block layer to review this too, though.
The integration into the block layer needs more review.

On Wed, Jul 10, 2019 at 03:56:04PM -0700, Satya Tangirala wrote:
> We introduce blk-crypto, which manages programming keyslots for struct
> bios. With blk-crypto, filesystems only need to call bio_crypt_set_ctx with
> the encryption key, algorithm and data_unit_num; they don't have to worry
> about getting a keyslot for each encryption context, as blk-crypto handles
> that. Blk-crypto also makes it possible for layered devices like device
> mapper to make use of inline encryption hardware.
> 
> Blk-crypto delegates crypto operations to inline encryption hardware when
> available, and also contains a software fallback to the kernel crypto API.
> For more details, refer to Documentation/block/blk-crypto.txt.

It's not necessarily a "software fallback", since the kernel crypto API
supports hardware crypto accelerators, just not *inline* hardware crypto
accelerators.  To avoid this inevitable confusion, can you please call
it the "crypto API fallback"?  This applies to the whole patch series,
including both the code and documentation.

> 
> Known issues:
> 1) We're allocating crypto_skcipher in blk_crypto_keyslot_program, which
> uses GFP_KERNEL to allocate memory, but this function is on the write
> path for IO - we need to add support for specifying a different flags
> to the crypto API.

You could use memalloc_noio_save() and memalloc_noio_restore(), rather
than gfp_flags.

> diff --git a/block/blk-crypto.c b/block/blk-crypto.c
> new file mode 100644
> index 000000000000..f41fb7819ae9
> --- /dev/null
> +++ b/block/blk-crypto.c
> @@ -0,0 +1,585 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2019 Google LLC
> + */

Perhaps include a reference to the documentation file?

Also, how about adding:

	#define pr_fmt(fmt) "blk-crypto: " fmt

... so that all log messages in this file automatically get an
appropriate prefix.

> +#include <linux/blk-crypto.h>
> +#include <linux/keyslot-manager.h>
> +#include <linux/mempool.h>
> +#include <linux/blk-cgroup.h>
> +#include <crypto/skcipher.h>
> +#include <crypto/algapi.h>
> +#include <linux/module.h>

This code is using the crypto API, but as-is
CONFIG_BLK_INLINE_ENCRYPTION can be enabled without also enabling the
crypto API, which will cause a build error.  The Kconfig option needs:

        select CRYPTO
        select CRYPTO_BLKCIPHER

> +
> +struct blk_crypt_mode {
> +	const char *cipher_str;
> +	size_t keysize;
> +};

In general, I think more comments in this file would be really helpful.

For example, can you document the fields of blk_crypt_mode?  E.g.

struct blk_crypt_mode {
        const char *cipher_str; /* crypto API name (for fallback case) */
        size_t keysize;         /* key size in bytes */
};

> +
> +static const struct blk_crypt_mode blk_crypt_modes[] = {
> +	[BLK_ENCRYPTION_MODE_AES_256_XTS] = {
> +		.cipher_str = "xts(aes)",
> +		.keysize = 64,
> +	},
> +};
> +
> +#define BLK_CRYPTO_MAX_KEY_SIZE 64
> +/* TODO: Do we want to make this user configurable somehow? */
> +static int blk_crypto_num_keyslots = 100;

This TODO is stale, since this patch already makes num_keyslots a kernel
command line parameter.

> +
> +static struct blk_crypto_keyslot {
> +	struct crypto_skcipher *tfm;
> +	enum blk_crypt_mode_num crypt_mode;
> +	u8 key[BLK_CRYPTO_MAX_KEY_SIZE];
> +} *blk_crypto_keyslots;
> +
> +struct work_mem {
> +	struct work_struct crypto_work;
> +	struct bio *bio;
> +};
> +
> +static struct keyslot_manager *blk_crypto_ksm;
> +static struct workqueue_struct *blk_crypto_wq;
> +static mempool_t *blk_crypto_page_pool;
> +static struct kmem_cache *blk_crypto_work_mem_cache;

It would be helpful to add a comment somewhere that makes it clear that
all this stuff is for the crypto API fallback, which is not used if the
disk natively supports inline encryption.

I'm concerned that people will read this code and draw the wrong
conclusion about where the encryption is actually being done in their
particular case.

> +
> +/* TODO: handle modes that need essiv */

There's a pending patchset that makes ESSIV accessible via
crypto_skcipher.  So ESSIV won't need special handling.  I suggest just
deleting this TODO comment for now.

> +static int blk_crypto_keyslot_program(void *priv, const u8 *key,
> +				      enum blk_crypt_mode_num crypt_mode,
> +				      unsigned int data_unit_size,
> +				      unsigned int slot)
> +{
> +	struct blk_crypto_keyslot *slotp = &blk_crypto_keyslots[slot];
> +	struct crypto_skcipher *tfm = slotp->tfm;
> +	const struct blk_crypt_mode *mode = &blk_crypt_modes[crypt_mode];
> +	size_t keysize = mode->keysize;
> +	int err;
> +
> +	if (crypt_mode != slotp->crypt_mode || !tfm) {

Nit: reversing this to '!tfm || crypt_mode != slotp->crypt_mode' would
be more logical because as the code is written, unused slots have tfm ==
NULL but an undefined crypt_mode.  It doesn't make sense to check the
undefined thing first, then the defined thing.

> +		evict_keyslot(slot);
> +		tfm = crypto_alloc_skcipher(
> +			mode->cipher_str, 0, 0);

Nit: the parameters to crypto_alloc_skcipher() fit in one line.

> +		if (IS_ERR(tfm))
> +			return PTR_ERR(tfm);
> +
> +		crypto_skcipher_set_flags(tfm,
> +					  CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);

Nit: the parameters to crypto_skcipher_set_flags() fit in one line.

> +static int blk_crypto_keyslot_find(void *priv,
> +				   const u8 *key,
> +				   enum blk_crypt_mode_num crypt_mode,
> +				   unsigned int data_unit_size_bytes)
> +{
> +	int slot;
> +	const size_t keysize = blk_crypt_modes[crypt_mode].keysize;
> +
> +	/* TODO: hashmap? */
> +	for (slot = 0; slot < blk_crypto_num_keyslots; slot++) {
> +		if (blk_crypto_keyslots[slot].crypt_mode == crypt_mode &&
> +		    !crypto_memneq(blk_crypto_keyslots[slot].key, key, keysize))
> +			return slot;
> +	}

There should be no TODO comments in the code, so please do something
about this one.  Note that we musn't leak other keys via timing
information, so a naive hashmap is not an appropriate solution.  So
perhaps this comment should just be deleted, or updated to explain the
timing attack problem and how it's solved.

> +static bool blk_crypt_mode_supported(void *priv,
> +				     enum blk_crypt_mode_num crypt_mode,
> +				     unsigned int data_unit_size)
> +{
> +	/* All blk_crypt_modes are required to have a software fallback. */
> +	return true;
> +}
> +
> +static const struct keyslot_mgmt_ll_ops blk_crypto_ksm_ll_ops = {
> +	.keyslot_program	= blk_crypto_keyslot_program,
> +	.keyslot_evict		= blk_crypto_keyslot_evict,
> +	.keyslot_find		= blk_crypto_keyslot_find,
> +	.crypt_mode_supported	= blk_crypt_mode_supported,
> +};

There's a missing "o" in blk_crypt_mode_supported().

> +
> +static void blk_crypto_encrypt_endio(struct bio *enc_bio)
> +{
> +	struct bio *src_bio = enc_bio->bi_private;
> +	struct bio_vec *enc_bvec, *enc_bvec_end;
> +
> +	enc_bvec = enc_bio->bi_io_vec;
> +	enc_bvec_end = enc_bvec + enc_bio->bi_vcnt;
> +	for (; enc_bvec != enc_bvec_end; enc_bvec++)
> +		mempool_free(enc_bvec->bv_page, blk_crypto_page_pool);

Nit: this could just be a regular loop over 'i':

	for (i = 0; i < enc_bio->bi_vcnt; i++)
		mempool_free(enc_bio->bi_io_vec[i].bv_page,
			     blk_crypto_page_pool);

It's one line shorter and slightly easier to read.

> +static struct bio *blk_crypto_clone_bio(struct bio *bio_src)
> +{
> +	struct bvec_iter iter;
> +	struct bio_vec bv;
> +	struct bio *bio;
> +
> +	bio = bio_alloc_bioset(GFP_NOIO, bio_segments(bio_src), NULL);
> +	if (!bio)
> +		return NULL;
> +	bio->bi_disk		= bio_src->bi_disk;
> +	bio->bi_opf		= bio_src->bi_opf;
> +	bio->bi_ioprio		= bio_src->bi_ioprio;
> +	bio->bi_write_hint	= bio_src->bi_write_hint;
> +	bio->bi_iter.bi_sector	= bio_src->bi_iter.bi_sector;
> +	bio->bi_iter.bi_size	= bio_src->bi_iter.bi_size;
> +
> +	bio_for_each_segment(bv, bio_src, iter)
> +		bio->bi_io_vec[bio->bi_vcnt++] = bv;
> +
> +	if (bio_integrity(bio_src)) {
> +		int ret;
> +
> +		ret = bio_integrity_clone(bio, bio_src, GFP_NOIO);
> +		if (ret < 0) {
> +			bio_put(bio);
> +			return NULL;
> +		}
> +	}

Nit: the code under bio_integrity() can be written more concisely:

	if (bio_integrity(bio_src) &&
	    bio_integrity_clone(bio, bio_src, GFP_NOIO) < 0) {
		bio_put(bio);
		return NULL;
	}

> +static int blk_crypto_encrypt_bio(struct bio **bio_ptr)
> +{
> +	struct bio *src_bio = *bio_ptr;
> +	int slot;
> +	struct skcipher_request *ciph_req = NULL;
> +	DECLARE_CRYPTO_WAIT(wait);
> +	struct bio_vec bv;
> +	struct bvec_iter iter;
> +	int err = 0;
> +	u64 curr_dun;
> +	union {
> +		__le64 dun;
> +		u8 bytes[16];
> +	} iv;
> +	struct scatterlist src, dst;
> +	struct bio *enc_bio;
> +	struct bio_vec *enc_bvec;
> +	int i, j;
> +	unsigned int num_sectors;
> +	int data_unit_size;

As I mentioned on v2, this function is difficult to understand because
it's so long.  I gave a suggestion to make it slightly shorter, which
was not taken.  It would be helpful if you responded to suggestions that
you're not accepting, since otherwise it's unclear whether the
suggestion was rejected, or was missed or forgotten.

Anyway, a new suggestion: it also seems the bio splitting can be nicely
made its own function, which would help.  E.g.:

static int blk_crypto_split_bio_if_needed(struct bio **bio_ptr)
{
       struct bio *bio = *bio_ptr;
       unsigned int i = 0;
       unsigned int num_sectors = 0;
       struct bio_vec bv;
       struct bvec_iter iter;

       bio_for_each_segment(bv, bio, iter) {
               num_sectors += bv.bv_len >> SECTOR_SHIFT;
               if (++i == BIO_MAX_PAGES)
                       break;
       }
       if (num_sectors < bio_sectors(bio)) {
               struct bio *split_bio;

               split_bio = bio_split(bio, num_sectors, GFP_NOIO, NULL);
               if (!split_bio) {
                       bio->bi_status = BLK_STS_RESOURCE;
                       return -ENOMEM;
               }
               bio_chain(split_bio, bio);
               generic_make_request(bio);
               *bio_ptr = split_bio;
       }
       return 0;
}

> +
> +	/* Split the bio if it's too big for single page bvec */
> +	i = 0;
> +	num_sectors = 0;
> +	data_unit_size = 1 << src_bio->bi_crypt_context->data_unit_size_bits;
> +	bio_for_each_segment(bv, src_bio, iter) {
> +		num_sectors += bv.bv_len >> 9;
> +		if (bv.bv_len % data_unit_size != 0) {
> +			src_bio->bi_status = BLK_STS_IOERR;
> +			return -EIO;
> +		}
> +		if (++i == BIO_MAX_PAGES)
> +			break;
> +	}

1.) The alignment check should be done on both bv_len and bv_offset.

2.) To make the behavior consistent, I also think it should be done
    regardless of whether the crypto API fallback is being used.

3.) As coded, this alignment check is broken because it's only being
    done on the first BIO_MAX_PAGES pages of the bio.

4.) '%' or '/' by a non-constant generally should be avoided in kernel
    code, because they can be very slow, and they aren't supported on
    64-bit variables on some architectures.  data_unit_size is always a
    power of 2, so use IS_ALIGNED() instead.

Instead, I suggest adding the following and calling it from early in
blk_crypto_submit_bio():

/* All I/O segments must be data unit aligned */
static int bio_crypt_check_alignment(struct bio *bio)
{
        int data_unit_size = 1 << bio->bi_crypt_context->data_unit_size_bits;
        struct bvec_iter iter;
        struct bio_vec bv;

        bio_for_each_segment(bv, bio, iter) {
                if (!IS_ALIGNED(bv.bv_len | bv.bv_offset, data_unit_size))
                        return -EIO;
        }
        return 0;
}

> +	if (num_sectors < bio_sectors(src_bio)) {
> +		struct bio *split_bio;
> +
> +		split_bio = bio_split(src_bio, num_sectors, GFP_NOIO, NULL);
> +		if (!split_bio) {
> +			src_bio->bi_status = BLK_STS_RESOURCE;
> +			return -ENOMEM;
> +		}
> +		bio_chain(split_bio, src_bio);
> +		generic_make_request(src_bio);
> +		*bio_ptr = split_bio;
> +		src_bio = *bio_ptr;
> +	}
> +
> +	enc_bio = blk_crypto_clone_bio(src_bio);
> +	if (!enc_bio) {
> +		src_bio->bi_status = BLK_STS_RESOURCE;
> +		return -ENOMEM;
> +	}
> +
> +	err = bio_crypt_ctx_acquire_keyslot(src_bio, blk_crypto_ksm);
> +	if (err) {
> +		src_bio->bi_status = BLK_STS_IOERR;
> +		bio_put(enc_bio);
> +		return err;
> +	}
> +	slot = bio_crypt_get_keyslot(src_bio);
> +
> +	ciph_req = skcipher_request_alloc(blk_crypto_keyslots[slot].tfm,
> +					  GFP_NOIO);
> +	if (!ciph_req) {
> +		src_bio->bi_status = BLK_STS_RESOURCE;
> +		err = -ENOMEM;
> +		bio_put(enc_bio);
> +		goto out_release_keyslot;
> +	}
> +
> +	skcipher_request_set_callback(ciph_req,
> +				      CRYPTO_TFM_REQ_MAY_BACKLOG |
> +				      CRYPTO_TFM_REQ_MAY_SLEEP,
> +				      crypto_req_done, &wait);

To help people follow this code, a few brief comments describing the
high-level tasks being accomplished here would be helpful.  E.g.:

       /*
        * Use the crypto API fallback keyslot manager to get a crypto_skcipher
        * for the algorithm and key, then allocate an skcipher_request for it.
        */

Then below:

	/* Encrypt each page in the bio */

and

		/* Encrypt each data unit in the page */


> +
> +	curr_dun = bio_crypt_data_unit_num(src_bio);
> +	sg_init_table(&src, 1);
> +	sg_init_table(&dst, 1);
> +	for (i = 0, enc_bvec = enc_bio->bi_io_vec; i < enc_bio->bi_vcnt;
> +	     enc_bvec++, i++) {
> +		struct page *page = enc_bvec->bv_page;

Nit: to make this slightly easier to read, you could just use a regular
loop over 'i' and assign enc_bvec in the loop:

	for (i = 0; i < enc_bio->bi_vcnt; i++) {
		struct bio_vec *enc_bvec = &enc_bio->bi_io_vec[i];


> +		struct page *ciphertext_page =
> +			mempool_alloc(blk_crypto_page_pool, GFP_NOIO);

Please rename 'page' => 'plaintext_page' to make it very clear which is
the plaintext and which is the ciphertext.

> +
> +		enc_bvec->bv_page = ciphertext_page;
> +
> +		if (!ciphertext_page)
> +			goto no_mem_for_ciph_page;
> +
> +		for (j = 0; j < enc_bvec->bv_len / data_unit_size; j++) {
> +			memset(&iv, 0, sizeof(iv));
> +			iv.dun = cpu_to_le64(curr_dun);
> +
> +			sg_set_page(&src, page, data_unit_size,
> +				    enc_bvec->bv_offset + j * data_unit_size);
> +			sg_set_page(&dst, ciphertext_page, data_unit_size,
> +				    enc_bvec->bv_offset + j * data_unit_size);
> +
> +			skcipher_request_set_crypt(ciph_req, &src, &dst,
> +						   data_unit_size, iv.bytes);
> +			err = crypto_wait_req(crypto_skcipher_encrypt(ciph_req),
> +					      &wait);
> +			if (err)
> +				goto no_mem_for_ciph_page;
> +			curr_dun++;
> +		}

This could be optimized slightly by only calling
skcipher_request_set_crypt() once per bio (since the scatterlists and IV
buffer are always the same), and by only doing the two sg_set_page()
calls once per page and instead updating the scatterlists after
encrypting each data unit:

	src.offset += data_unit_size;
	dst.offset += data_unit_size;

And the loop can be:

	for (j = 0; j < enc_bvec->bv_len; j += data_unit_size) {

... so that no divisions or multiplications are needed.

> +		continue;
> +no_mem_for_ciph_page:
> +		err = -ENOMEM;
> +		for (j = i - 1; j >= 0; j--) {
> +			mempool_free(enc_bio->bi_io_vec[j].bv_page,
> +				     blk_crypto_page_pool);
> +		}
> +		src_bio->bi_status = BLK_STS_RESOURCE;
> +		bio_put(enc_bio);
> +		goto out_release_cipher;
> +	}

If crypto_skcipher_encrypt() fails, a bounce page is leaked.  Also, the
failure is not necessarily caused by "no memory".

To fix the former, we can increment 'i' immediately after the page has
been allocated.  To fix the latter, we can set bi_status at the place
the error happened.

To make the error handling easier to read and less error prone, how
about it also moving it to the end of the function, including the
bio_put(enc_bio):

        enc_bio = NULL;
        err = 0;
        goto out_free_ciph_req;

out_free_bounce_pages:
        while (i > 0)
                mempool_free(enc_bio->bi_io_vec[--i].bv_page,
                             blk_crypto_page_pool);
out_free_ciph_req:
        skcipher_request_free(ciph_req);
out_release_keyslot:
        bio_crypt_ctx_release_keyslot(src_bio);
out_put_enc_bio:
        if (enc_bio)
                bio_put(enc_bio);
        return err;

> +
> +	enc_bio->bi_private = src_bio;
> +	enc_bio->bi_end_io = blk_crypto_encrypt_endio;
> +
> +	*bio_ptr = enc_bio;
> +out_release_cipher:
> +	skcipher_request_free(ciph_req);
> +out_release_keyslot:
> +	bio_crypt_ctx_release_keyslot(src_bio);
> +	return err;
> +}
> +
> +/*
> + * TODO: assumption right now is:
> + * each segment in bio has length divisible by the data_unit_size
> + */

Why is this a TODO?  What's wrong with just failing bio's that aren't
properly aligned?

> +static void blk_crypto_decrypt_bio(struct work_struct *w)
> +{
> +	struct work_mem *work_mem =
> +		container_of(w, struct work_mem, crypto_work);
> +	struct bio *bio = work_mem->bio;
> +	int slot;
> +	struct skcipher_request *ciph_req;
> +	DECLARE_CRYPTO_WAIT(wait);
> +	struct bio_vec bv;
> +	struct bvec_iter iter;
> +	u64 curr_dun;
> +	union {
> +		__le64 dun;
> +		u8 bytes[16];
> +	} iv;
> +	struct scatterlist sg;
> +	int err;
> +	int data_unit_size = 1 << bio->bi_crypt_context->data_unit_size_bits;
> +	int i;
> +
> +	kmem_cache_free(blk_crypto_work_mem_cache, work_mem);

Nit: freeing the work_mem is cleanup work that always must be done,
similar to calling bio_endio().  So I suggest moving this to the end of
this function, after bio_endio().  Otherwise it would be easy for a
future patch to accidentally introduce a use-after-free of work_mem.

> +
> +	err = bio_crypt_ctx_acquire_keyslot(bio, blk_crypto_ksm);
> +	if (err) {
> +		bio->bi_status = BLK_STS_RESOURCE;
> +		goto out_no_keyslot;
> +	}
> +
> +	slot = bio_crypt_get_keyslot(bio);
> +	ciph_req = skcipher_request_alloc(blk_crypto_keyslots[slot].tfm,
> +					  GFP_NOIO);
> +	if (!ciph_req) {
> +		bio->bi_status = BLK_STS_RESOURCE;
> +		goto out;
> +	}
> +
> +	skcipher_request_set_callback(ciph_req,
> +				      CRYPTO_TFM_REQ_MAY_BACKLOG |
> +				      CRYPTO_TFM_REQ_MAY_SLEEP,
> +				      crypto_req_done, &wait);
> +
> +	curr_dun = bio_crypt_sw_data_unit_num(bio);
> +	sg_init_table(&sg, 1);
> +	__bio_for_each_segment(bv, bio, iter,
> +			       bio->bi_crypt_context->crypt_iter) {
> +		if (bv.bv_len % data_unit_size != 0) {
> +			bio->bi_status = BLK_STS_IOERR;
> +			err = -EIO;
> +			goto out;
> +		}
> +		for (i = 0; i < bv.bv_len / data_unit_size; i++) {
> +			struct page *page = bv.bv_page;
> +
> +			memset(&iv, 0, sizeof(iv));
> +			iv.dun = cpu_to_le64(curr_dun);
> +
> +			sg_set_page(&sg, page, data_unit_size,
> +				    bv.bv_offset + i * data_unit_size);
> +			skcipher_request_set_crypt(ciph_req, &sg, &sg,
> +						   data_unit_size, iv.bytes);
> +			err = crypto_wait_req(crypto_skcipher_decrypt(ciph_req),
> +					      &wait);
> +			if (err) {
> +				bio->bi_status = BLK_STS_IOERR;
> +				goto out;
> +			}
> +			curr_dun++;
> +		}
> +	}

Most of the comments I made for the encryption case apply here too.

> +
> +out:
> +	skcipher_request_free(ciph_req);
> +	bio_crypt_ctx_release_keyslot(bio);
> +out_no_keyslot:
> +	bio_endio(bio);
> +}
> +
> +static void blk_crypto_queue_decrypt_bio(struct bio *bio)
> +{
> +	struct work_mem *work_mem =
> +		kmem_cache_zalloc(blk_crypto_work_mem_cache, GFP_ATOMIC);
> +
> +	if (!work_mem) {
> +		bio->bi_status = BLK_STS_RESOURCE;
> +		return bio_endio(bio);
> +	}

It's not conventional to chain 'void' return values like this.

Try to be as boring as possible.  Just write:

		bio_endio(bio);
		return;

> +
> +	INIT_WORK(&work_mem->crypto_work, blk_crypto_decrypt_bio);
> +	work_mem->bio = bio;
> +	queue_work(blk_crypto_wq, &work_mem->crypto_work);
> +}
> +
> +/**
> + * blk_crypto_submit_bio - handle submitting bio for inline encryption
> + *
> + * @bio_ptr: pointer to original bio pointer
> + *
> + * If the bio doesn't have inline encryption enabled or the submitter already
> + * specified a keyslot for the target device, do nothing.  Else, a raw key must
> + * have been provided, so acquire a device keyslot for it if supported.  Else,
> + * use the software crypto fallback.
> + *
> + * When the software fallback is used for encryption, blk-crypto may choose to
> + * split the bio into 2 - one that will continue to be processed and the other
> + * that will be resubmitted via generic_make_request. *bio_ptr will be updated
> + * to the first bio (the one that will continue to be processed).

The second paragraph is misleading because it doesn't explain that
*bio_ptr is actually updated to point to the bounce bio.

> + *
> + * Return: 0 if bio submission should continue; nonzero if bio_endio() was
> + *        already called so bio submission should abort.
> + */
> +int blk_crypto_submit_bio(struct bio **bio_ptr)
> +{
> +	struct bio *bio = *bio_ptr;
> +	struct request_queue *q;
> +	int err;
> +	struct bio_crypt_ctx *crypt_ctx;
> +
> +	if (!bio_is_encrypted(bio) || !bio_has_data(bio))
> +		return 0;
> +
> +	/*
> +	 * When a read bio is marked for sw decryption, its bi_iter is saved
> +	 * so that when we decrypt the bio later, we know what part of it was
> +	 * marked for sw decryption (when the bio is passed down after
> +	 * blk_crypto_submit bio, it may be split or advanced so we cannot rely
> +	 * on the bi_iter while decrypting in blk_crypto_endio)
> +	 */
> +	if (bio_crypt_swhandled(bio))
> +		return 0;
> +
> +	crypt_ctx = bio->bi_crypt_context;
> +	q = bio->bi_disk->queue;
> +
> +	if (bio_crypt_has_keyslot(bio)) {
> +		/* Key already programmed into device? */
> +		if (q->ksm == crypt_ctx->processing_ksm)
> +			return 0;
> +
> +		/* Nope, release the existing keyslot. */
> +		bio_crypt_ctx_release_keyslot(bio);
> +	}
> +
> +	/* Get device keyslot if supported */
> +	if (q->ksm) {
> +		err = bio_crypt_ctx_acquire_keyslot(bio, q->ksm);
> +		if (!err) {
> +			pr_warn_once("blk-crypto: failed to acquire keyslot for %s (err=%d).  Falling back to software crypto.\n",
> +				     bio->bi_disk->disk_name, err);
> +			return 0;
> +		}

This warning message should go in the err != 0 case, not err == 0.

> +	}
> +
> +	/* Fallback to software crypto */
> +	if (bio_data_dir(bio) == WRITE) {
> +		/* Encrypt the data now */
> +		err = blk_crypto_encrypt_bio(bio_ptr);
> +		if (err)
> +			goto out_encrypt_err;
> +	} else {
> +		/* Mark bio as swhandled */
> +		bio->bi_crypt_context->processing_ksm = blk_crypto_ksm;
> +		bio->bi_crypt_context->crypt_iter = bio->bi_iter;
> +		bio->bi_crypt_context->sw_data_unit_num =
> +				bio->bi_crypt_context->data_unit_num;
> +	}
> +	return 0;
> +out_encrypt_err:
> +	bio_endio(bio);
> +	return err;
> +}
> +
> +/**
> + * blk_crypto_endio - clean up bio w.r.t inline encryption during bio_endio
> + *
> + * @bio - the bio to clean up
> + *
> + * If blk_crypto_submit_bio decided to fallback to software crypto for this
> + * bio, we queue the bio for decryption into a workqueue and return false,
> + * and call bio_endio(bio) at a later time (after the bio has been decrypted).
> + *
> + * If the bio is not to be decrypted in software, this function releases the
> + * reference to the keyslot that blk_crypto_submit_bio got.
> + *
> + * Return: true if bio_endio should continue; false otherwise (bio_endio will
> + * be called again when bio has been decrypted).
> + */
> +bool blk_crypto_endio(struct bio *bio)
> +{
> +	if (bio_crypt_swhandled(bio)) {
> +		/*
> +		 * The only bios that are swhandled when they reach here
> +		 * are those with bio_data_dir(bio) == READ, since WRITE
> +		 * bios that are encrypted by software fallback are handled
> +		 * by blk_crypto_encrypt_endio.
> +		 */
> +		blk_crypto_queue_decrypt_bio(bio);
> +		return false;
> +	}

This should only do the decryption if there was no I/O error.

> +
> +	if (bio_is_encrypted(bio) && bio_crypt_has_keyslot(bio))
> +		bio_crypt_ctx_release_keyslot(bio);
> +
> +	return true;

Also it seems that blk_crypto_endio() should mirror
blk_crypto_submit_bio() and start with:

	if (!bio_is_encrypted(bio) || !bio_has_data(bio))
		return true;

Otherwise the bio_has_data() case might be handled inconsistently.  And
it's good to check bio_is_encrypted() first, so that the unencrypted
case is as fast and easy to understand as possible.

Also, blk_crypto_endio() always releases the keyslot, even if it was
provided by the submitter of the bio.  Shouldn't it only release the
keyslot if it was acquired by blk_crypto_submit_bio()?

> +}
> +
> +int __init blk_crypto_init(void)
> +{
> +	blk_crypto_ksm = keyslot_manager_create(blk_crypto_num_keyslots,
> +						&blk_crypto_ksm_ll_ops,
> +						NULL);
> +	if (!blk_crypto_ksm)
> +		goto out_ksm;
> +
> +	blk_crypto_wq = alloc_workqueue("blk_crypto_wq",
> +					WQ_UNBOUND | WQ_HIGHPRI |
> +					WQ_MEM_RECLAIM,
> +					num_online_cpus());
> +	if (!blk_crypto_wq)
> +		goto out_wq;
> +
> +	blk_crypto_keyslots = kcalloc(blk_crypto_num_keyslots,
> +				      sizeof(*blk_crypto_keyslots),
> +				      GFP_KERNEL);
> +	if (!blk_crypto_keyslots)
> +		goto out_blk_crypto_keyslots;
> +
> +	blk_crypto_page_pool =
> +		mempool_create_page_pool(num_prealloc_bounce_pg, 0);
> +	if (!blk_crypto_page_pool)
> +		goto out_bounce_pool;
> +
> +	blk_crypto_work_mem_cache = KMEM_CACHE(work_mem, SLAB_RECLAIM_ACCOUNT);
> +	if (!blk_crypto_work_mem_cache)
> +		goto out_work_mem_cache;
> +
> +	return 0;
> +
> +out_work_mem_cache:
> +	mempool_destroy(blk_crypto_page_pool);
> +	blk_crypto_page_pool = NULL;
> +out_bounce_pool:
> +	kzfree(blk_crypto_keyslots);
> +	blk_crypto_keyslots = NULL;
> +out_blk_crypto_keyslots:
> +	destroy_workqueue(blk_crypto_wq);
> +	blk_crypto_wq = NULL;
> +out_wq:
> +	keyslot_manager_destroy(blk_crypto_ksm);
> +	blk_crypto_ksm = NULL;
> +out_ksm:
> +	pr_warn("No memory for blk-crypto software fallback.");
> +	return -ENOMEM;
> +}

Nit: I find it easier to read error labels when they describe what is
done at them, rather than what was done just before the goto.
I.e. use out:, out_destroy_ksm:, out_destroy_workqueue:, etc.

> +
> +module_param(blk_crypto_num_keyslots, int, 0);
> +MODULE_PARM_DESC(blk_crypto_num_keyslots,
> +		 "Number of keyslots for software fallback in blk-crypto.");
> +module_param(num_prealloc_bounce_pg, uint, 0);
> +MODULE_PARM_DESC(num_prealloc_bounce_pg,
> +	"Number of preallocated bounce pages for blk-crypto to use during software fallback encryption");

I believe it's more common for the module_param() statements to go at
the top of the file, next to the actual variables.

Also, the module parameter names are inconsistent.  The first parameter
will be "blk_crypto.blk_crypto_num_keyslots" on command line and second
parameter will be "blk_crypto.num_prealloc_bounce_pg" on command line.

It should be "blk_crypto.num_keyslots" for the first.  No need to say
"blk_crypto" twice.

module_param_named() can be used to still prefix the C variable names
with "blk_crypto_".

> diff --git a/include/linux/blk-crypto.h b/include/linux/blk-crypto.h
> new file mode 100644
> index 000000000000..cbb5bea6dcdb
> --- /dev/null
> +++ b/include/linux/blk-crypto.h
> @@ -0,0 +1,40 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright 2019 Google LLC
> + */
> +
> +#ifndef __LINUX_BLK_CRYPTO_H
> +#define __LINUX_BLK_CRYPTO_H
> +
> +#include <linux/types.h>
> +
> +#ifdef CONFIG_BLK_INLINE_ENCRYPTION
> +
> +struct bio;

This forward declaration should go outside the ifdef, since 'struct bio'
is referred to in both cases.

> +
> +int blk_crypto_init(void);
> +
> +int blk_crypto_submit_bio(struct bio **bio_ptr);
> +
> +bool blk_crypto_endio(struct bio *bio);
> +
> +#else /* CONFIG_BLK_INLINE_ENCRYPTION */
> +
> +static inline int blk_crypto_init(void)
> +{
> +	return 0;
> +}
> +
> +static inline int blk_crypto_submit_bio(struct bio **bio)
> +{
> +	return 0;
> +}

To be consistent with the other declaration, the parameter name here
should be 'bio_ptr', not 'bio'.

> +
> +static inline bool blk_crypto_endio(struct bio *bio)
> +{
> +	return true;
> +}
> +
> +#endif /* CONFIG_BLK_INLINE_ENCRYPTION */
> +
> +#endif /* __LINUX_BLK_CRYPTO_H */
> -- 
> 2.22.0.410.gd8fdbe21b5-goog
> 

- Eric


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Re: [f2fs-dev] [PATCH 2/8] block: Add encryption context to struct bio

[Jens Axboe]

On 7/10/19 4:56 PM, Satya Tangirala wrote:
> We must have some way of letting a storage device driver know what
> encryption context it should use for en/decrypting a request. However,
> it's the filesystem/fscrypt that knows about and manages encryption
> contexts. As such, when the filesystem layer submits a bio to the block
> layer, and this bio eventually reaches a device driver with support for
> inline encryption, the device driver will need to have been told the
> encryption context for that bio.
> 
> We want to communicate the encryption context from the filesystem layer
> to the storage device along with the bio, when the bio is submitted to the
> block layer. To do this, we add a struct bio_crypt_ctx to struct bio, which
> can represent an encryption context (note that we can't use the bi_private
> field in struct bio to do this because that field does not function to pass
> information across layers in the storage stack). We also introduce various
> functions to manipulate the bio_crypt_ctx and make the bio/request merging
> logic aware of the bio_crypt_ctx.

A few minor comments below. Don't see something totally horrible with
your approach.


> diff --git a/block/bio-crypt-ctx.c b/block/bio-crypt-ctx.c
> new file mode 100644
> index 000000000000..8b884ef32007
> --- /dev/null
> +++ b/block/bio-crypt-ctx.c
> @@ -0,0 +1,117 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright 2019 Google LLC
> + */
> +
> +#include <linux/bio.h>
> +#include <linux/blkdev.h>
> +#include <linux/slab.h>
> +#include <linux/keyslot-manager.h>
> +
> +struct bio_crypt_ctx *bio_crypt_alloc_ctx(gfp_t gfp_mask)
> +{
> +	return kzalloc(sizeof(struct bio_crypt_ctx), gfp_mask);
> +}

I think you'll want this to be mempool backed.

> +EXPORT_SYMBOL(bio_crypt_alloc_ctx);
> +
> +void bio_crypt_free_ctx(struct bio *bio)
> +{
> +	kzfree(bio->bi_crypt_context);
> +	bio->bi_crypt_context = NULL;
> +}
> +EXPORT_SYMBOL(bio_crypt_free_ctx);
> +
> +int bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask)
> +{
> +	if (!bio_is_encrypted(src))
> +		return 0;

Was going to suggest dumping this helper, but that won't work for the
case where inline encryption isn't enabled. How about renaming it so it
is easier to grok what it tests, bio_has_crypt_ctx() or something like
that.

> +	dst->bi_crypt_context = bio_crypt_alloc_ctx(gfp_mask);
> +	if (!dst->bi_crypt_context)
> +		return -ENOMEM;

That's why you need the mempool...

> diff --git a/block/blk-merge.c b/block/blk-merge.c
> index 17713d7d98d5..f416e7f38270 100644
> --- a/block/blk-merge.c
> +++ b/block/blk-merge.c
> @@ -531,6 +531,9 @@ static inline int ll_new_hw_segment(struct request_queue *q,
>   	if (blk_integrity_merge_bio(q, req, bio) == false)
>   		goto no_merge;
>   
> +	if (WARN_ON(!bio_crypt_ctx_compatible(bio, req->bio)))
> +		goto no_merge;

This is really a debug check, as that shouldn't happen unless you have a
bug in your merge helpers. I think we can do one of two things here:

1) Rely on this check only for merging, similarly to what the integrity
   code does. This means the WARN() goes away and (most of) the  other
   merge checks can go away.

2) Keep it, but change it to a WARN_ON_ONCE().

> @@ -696,8 +699,13 @@ static enum elv_merge blk_try_req_merge(struct request *req,
>   {
>   	if (blk_discard_mergable(req))
>   		return ELEVATOR_DISCARD_MERGE;
> -	else if (blk_rq_pos(req) + blk_rq_sectors(req) == blk_rq_pos(next))
> +	else if (blk_rq_pos(req) + blk_rq_sectors(req) == blk_rq_pos(next)) {
> +		if (!bio_crypt_ctx_back_mergeable(
> +			req->bio, blk_rq_sectors(req), next->bio)) {
> +			return ELEVATOR_NO_MERGE;
> +		}
>   		return ELEVATOR_BACK_MERGE;
> +	}

Weird line breaks aside, see above comment. More in this file.

> diff --git a/include/linux/bio.h b/include/linux/bio.h
> index ef9c6e2e92bc..4e664d6441d5 100644
> --- a/include/linux/bio.h
> +++ b/include/linux/bio.h
> @@ -572,6 +572,196 @@ enum blk_crypt_mode_num {
>   	 */
>   };
>   
> +#ifdef CONFIG_BLK_INLINE_ENCRYPTION
> +struct bio_crypt_ctx {
> +	int keyslot;
> +	u8 *raw_key;
> +	enum blk_crypt_mode_num crypt_mode;
> +	u64 data_unit_num;
> +	unsigned int data_unit_size_bits;
> +
> +	/*
> +	 * The keyslot manager where the key has been programmed
> +	 * with keyslot.
> +	 */
> +	struct keyslot_manager *processing_ksm;
> +
> +	/*
> +	 * Copy of the bvec_iter when this bio was submitted.
> +	 * We only want to en/decrypt the part of the bio
> +	 * as described by the bvec_iter upon submission because
> +	 * bio might be split before being resubmitted
> +	 */
> +	struct bvec_iter crypt_iter;
> +	u64 sw_data_unit_num;
> +};

[snip]

Let's move that to a separate file, with the other crypt specific bits.
Just include it from bio.h.


> +static inline u64 bio_crypt_data_unit_num(struct bio *bio)
> +{
> +	WARN_ON(!bio_is_encrypted(bio));
> +	return bio->bi_crypt_context->data_unit_num;
> +}
> +
> +static inline u64 bio_crypt_sw_data_unit_num(struct bio *bio)
> +{
> +	WARN_ON(!bio_is_encrypted(bio));
> +	return bio->bi_crypt_context->sw_data_unit_num;
> +}

These WARN()'s are a bit weird.

> +static inline u64 bio_crypt_data_unit_num(struct bio *bio)
> +{
> +	WARN_ON(1);
> +	return 0;
> +}

And this one definitely needs to go.

> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
> index 95202f80676c..0b794fe3530a 100644
> --- a/include/linux/blk_types.h
> +++ b/include/linux/blk_types.h
> @@ -137,6 +137,8 @@ static inline void bio_issue_init(struct bio_issue *issue,
>   			((u64)size << BIO_ISSUE_SIZE_SHIFT));
>   }
>   
> +struct bio_crypt_ctx;

Place this with the other forward declarations.

-- 
Jens Axboe



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Re: [f2fs-dev] [PATCH 3/8] block: blk-crypto for Inline Encryption

[Jens Axboe]

On 7/10/19 4:56 PM, Satya Tangirala wrote:
> We introduce blk-crypto, which manages programming keyslots for struct
> bios. With blk-crypto, filesystems only need to call bio_crypt_set_ctx with
> the encryption key, algorithm and data_unit_num; they don't have to worry
> about getting a keyslot for each encryption context, as blk-crypto handles
> that. Blk-crypto also makes it possible for layered devices like device
> mapper to make use of inline encryption hardware.
> 
> Blk-crypto delegates crypto operations to inline encryption hardware when
> available, and also contains a software fallback to the kernel crypto API.
> For more details, refer to Documentation/block/blk-crypto.txt.
> 
> Known issues:
> 1) We're allocating crypto_skcipher in blk_crypto_keyslot_program, which
> uses GFP_KERNEL to allocate memory, but this function is on the write
> path for IO - we need to add support for specifying a different flags
> to the crypto API.

That's a must-fix before merging, btw.

> @@ -1018,7 +1019,9 @@ blk_qc_t generic_make_request(struct bio *bio)
>   			/* Create a fresh bio_list for all subordinate requests */
>   			bio_list_on_stack[1] = bio_list_on_stack[0];
>   			bio_list_init(&bio_list_on_stack[0]);
> -			ret = q->make_request_fn(q, bio);
> +
> +			if (!blk_crypto_submit_bio(&bio))
> +				ret = q->make_request_fn(q, bio);
>   
>   			blk_queue_exit(q);

Why isn't this just stacking the ->make_request_fn() instead? Then we
could get this out of the hot path.

-- 
Jens Axboe



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