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* [PATCH v5 0/5] add support for inline encryption to device mapper
@ 2021-02-11 22:53 Satya Tangirala
  2021-02-11 22:53 ` [PATCH v5 1/5] block: keyslot-manager: Introduce passthrough keyslot manager Satya Tangirala
                   ` (4 more replies)
  0 siblings, 5 replies; 6+ messages in thread
From: Satya Tangirala @ 2021-02-11 22:53 UTC (permalink / raw)
  To: linux-block, linux-kernel, dm-devel
  Cc: Jens Axboe, Alasdair Kergon, Mike Snitzer, Eric Biggers, Satya Tangirala

This patch series adds support for inline encryption to the device mapper.

Patch 1 introduces the "passthrough" keyslot manager.

The regular keyslot manager is designed for inline encryption hardware that
have only a small fixed number of keyslots. A DM device itself does not
actually have only a small fixed number of keyslots - it doesn't actually
have any keyslots in the first place, and programming an encryption context
into a DM device doesn't make much semantic sense. It is possible for a DM
device to set up a keyslot manager with some "sufficiently large" number of
keyslots in its request queue, so that upper layers can use the inline
encryption capabilities of the DM device's underlying devices, but the
memory being allocated for the DM device's keyslots is a waste since they
won't actually be used by the DM device.

The passthrough keyslot manager solves this issue - when the block layer
sees that a request queue has a passthrough keyslot manager, it doesn't
attempt to program any encryption context into the keyslot manager. The
passthrough keyslot manager only allows the device to expose its inline
encryption capabilities, and a way for upper layers to evict keys if
necessary.

There also exist inline encryption hardware that can handle encryption
contexts directly, and allow users to pass them a data request along with
the encryption context (as opposed to inline encryption hardware that
require users to first program a keyslot with an encryption context, and
then require the users to pass the keyslot index with the data request).
Such devices can also make use of the passthrough keyslot manager.

Patch 2 introduces some keyslot manager functions useful for the device
mapper.

Patch 3 introduces the changes for inline encryption support for the device
mapper. A DM device only exposes the intersection of the crypto
capabilities of its underlying devices. This is so that in case a bio with
an encryption context is eventually mapped to an underlying device that
doesn't support that encryption context, the blk-crypto-fallback's cipher
tfms are allocated ahead of time by the call to blk_crypto_start_using_key.

Each DM target can now also specify the "DM_TARGET_PASSES_CRYPTO" flag in
the target type features to opt-in to supporting passing through the
underlying inline encryption capabilities.  This flag is needed because it
doesn't make much semantic sense for certain targets like dm-crypt to
expose the underlying inline encryption capabilities to the upper layers.
Again, the DM exposes inline encryption capabilities of the underlying
devices only if all of them opt-in to passing through inline encryption
support.

A keyslot manager is created for a table when it is loaded. However, the
mapped device's exposed capabilities *only* updated once the table is
swapped in (until the new table is swapped in, the mapped device continues
to expose the old table's crypto capabilities).

This patch only allows the keyslot manager's capabilities to *expand*
because of table changes. Any attempt to load a new table that doesn't
support a crypto capability that the old table did is rejected.

This patch also only exposes the intersection of the underlying device's
capabilities, which has the effect of causing en/decryption of a bio to
fall back to the kernel crypto API (if the fallback is enabled) whenever
any of the underlying devices doesn't support the encryption context of the
bio - it might be possible to make the bio only fall back to the kernel
crypto API if the bio's target underlying device doesn't support the bio's
encryption context, but the use case may be uncommon enough in the first
place not to warrant worrying about it right now.

Patch 4 makes DM evict a key from all its underlying devices when asked to
evict a key.

Patch 5 makes some DM targets opt-in to passing through inline encryption
support. It does not (yet) try to enable this option with dm-raid, since
users can "hot add" disks to a raid device, which makes this not completely
straightforward (we'll need to ensure that any "hot added" disks must have
a superset of the inline encryption capabilities of the rest of the disks
in the raid device, due to the way Patch 2 of this series works).

Changes v4 => v5:
 - Fixup/improve comments as suggested by Eric
 - add Acked-bys and Reviewed-bys

Changes v3 => v4:
 - Allocate the memory for the ksm of the mapped device in
   dm_table_complete(), and install the ksm in the md queue in __bind()
   (as suggested by Mike). Also drop patch 5 from v3 since it's no longer
   needed.
 - Some cleanups

Changes v2 => v3:
 - Split up the main DM patch into 4 separate patches
 - Removed the priv variable added to struct keyslot manager in v2
 - Use a flag in target type features for opting-in to inline encryption
   support, instead of using "may_passthrough_inline_crypto"
 - cleanups, improve docs and restructure code

Changes v1 => v2:
 - Introduce private field to struct blk_keyslot_manager
 - Allow the DM keyslot manager to expand its crypto capabilities if the
   table is changed.
 - Make DM reject table changes that would otherwise cause crypto
   capabilities to be dropped.
 - Allocate the DM device's keyslot manager only when at least one crypto
   capability is supported (since a NULL value for q->ksm represents "no
   crypto support" anyway).
 - Remove the struct blk_keyslot_manager field from struct mapped_device.
   This patch now relies on just directly setting up the keyslot manager in
   the request queue, since each DM device is tied to only 1 queue.

Satya Tangirala (5):
  block: keyslot-manager: Introduce passthrough keyslot manager
  block: keyslot-manager: Introduce functions for device mapper support
  dm: add support for passing through inline crypto support
  dm: support key eviction from keyslot managers of underlying devices
  dm: set DM_TARGET_PASSES_CRYPTO feature for some targets

 block/blk-crypto.c              |   1 +
 block/keyslot-manager.c         | 146 ++++++++++++++++++++++
 drivers/md/dm-core.h            |  12 ++
 drivers/md/dm-flakey.c          |   4 +-
 drivers/md/dm-linear.c          |   5 +-
 drivers/md/dm-table.c           | 212 ++++++++++++++++++++++++++++++++
 drivers/md/dm.c                 |  18 ++-
 include/linux/device-mapper.h   |  12 ++
 include/linux/keyslot-manager.h |  11 ++
 9 files changed, 417 insertions(+), 4 deletions(-)

-- 
2.30.0.478.g8a0d178c01-goog


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH v5 1/5] block: keyslot-manager: Introduce passthrough keyslot manager
  2021-02-11 22:53 [PATCH v5 0/5] add support for inline encryption to device mapper Satya Tangirala
@ 2021-02-11 22:53 ` Satya Tangirala
  2021-02-11 22:53 ` [PATCH v5 2/5] block: keyslot-manager: Introduce functions for device mapper support Satya Tangirala
                   ` (3 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: Satya Tangirala @ 2021-02-11 22:53 UTC (permalink / raw)
  To: linux-block, linux-kernel, dm-devel
  Cc: Jens Axboe, Alasdair Kergon, Mike Snitzer, Eric Biggers, Satya Tangirala

The device mapper may map over devices that have inline encryption
capabilities, and to make use of those capabilities, the DM device must
itself advertise those inline encryption capabilities. One way to do this
would be to have the DM device set up a keyslot manager with a
"sufficiently large" number of keyslots, but that would use a lot of
memory. Also, the DM device itself has no "keyslots", and it doesn't make
much sense to talk about "programming a key into a DM device's keyslot
manager", so all that extra memory used to represent those keyslots is just
wasted. All a DM device really needs to be able to do is advertise the
crypto capabilities of the underlying devices in a coherent manner and
expose a way to evict keys from the underlying devices.

There are also devices with inline encryption hardware that do not
have a limited number of keyslots. One can send a raw encryption key along
with a bio to these devices (as opposed to typical inline encryption
hardware that require users to first program a raw encryption key into a
keyslot, and send the index of that keyslot along with the bio). These
devices also only need the same things from the keyslot manager that DM
devices need - a way to advertise crypto capabilities and potentially a way
to expose a function to evict keys from hardware.

So we introduce a "passthrough" keyslot manager that provides a way to
represent a keyslot manager that doesn't have just a limited number of
keyslots, and for which do not require keys to be programmed into keyslots.
DM devices can set up a passthrough keyslot manager in their request
queues, and advertise appropriate crypto capabilities based on those of the
underlying devices. Blk-crypto does not attempt to program keys into any
keyslots in the passthrough keyslot manager. Instead, if/when the bio is
resubmitted to the underlying device, blk-crypto will try to program the
key into the underlying device's keyslot manager.

Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
---
 block/keyslot-manager.c         | 39 +++++++++++++++++++++++++++++++++
 include/linux/keyslot-manager.h |  2 ++
 2 files changed, 41 insertions(+)

diff --git a/block/keyslot-manager.c b/block/keyslot-manager.c
index 86f8195d8039..ac7ce83a76e8 100644
--- a/block/keyslot-manager.c
+++ b/block/keyslot-manager.c
@@ -62,6 +62,11 @@ static inline void blk_ksm_hw_exit(struct blk_keyslot_manager *ksm)
 		pm_runtime_put_sync(ksm->dev);
 }
 
+static inline bool blk_ksm_is_passthrough(struct blk_keyslot_manager *ksm)
+{
+	return ksm->num_slots == 0;
+}
+
 /**
  * blk_ksm_init() - Initialize a keyslot manager
  * @ksm: The keyslot_manager to initialize.
@@ -205,6 +210,10 @@ blk_status_t blk_ksm_get_slot_for_key(struct blk_keyslot_manager *ksm,
 	int err;
 
 	*slot_ptr = NULL;
+
+	if (blk_ksm_is_passthrough(ksm))
+		return BLK_STS_OK;
+
 	down_read(&ksm->lock);
 	slot = blk_ksm_find_and_grab_keyslot(ksm, key);
 	up_read(&ksm->lock);
@@ -325,6 +334,16 @@ int blk_ksm_evict_key(struct blk_keyslot_manager *ksm,
 	struct blk_ksm_keyslot *slot;
 	int err = 0;
 
+	if (blk_ksm_is_passthrough(ksm)) {
+		if (ksm->ksm_ll_ops.keyslot_evict) {
+			blk_ksm_hw_enter(ksm);
+			err = ksm->ksm_ll_ops.keyslot_evict(ksm, key, -1);
+			blk_ksm_hw_exit(ksm);
+			return err;
+		}
+		return 0;
+	}
+
 	blk_ksm_hw_enter(ksm);
 	slot = blk_ksm_find_keyslot(ksm, key);
 	if (!slot)
@@ -360,6 +379,9 @@ void blk_ksm_reprogram_all_keys(struct blk_keyslot_manager *ksm)
 {
 	unsigned int slot;
 
+	if (blk_ksm_is_passthrough(ksm))
+		return;
+
 	/* This is for device initialization, so don't resume the device */
 	down_write(&ksm->lock);
 	for (slot = 0; slot < ksm->num_slots; slot++) {
@@ -401,3 +423,20 @@ void blk_ksm_unregister(struct request_queue *q)
 {
 	q->ksm = NULL;
 }
+
+/**
+ * blk_ksm_init_passthrough() - Init a passthrough keyslot manager
+ * @ksm: The keyslot manager to init
+ *
+ * Initialize a passthrough keyslot manager.
+ * Called by e.g. storage drivers to set up a keyslot manager in their
+ * request_queue, when the storage driver wants to manage its keys by itself.
+ * This is useful for inline encryption hardware that doesn't have the concept
+ * of keyslots, and for layered devices.
+ */
+void blk_ksm_init_passthrough(struct blk_keyslot_manager *ksm)
+{
+	memset(ksm, 0, sizeof(*ksm));
+	init_rwsem(&ksm->lock);
+}
+EXPORT_SYMBOL_GPL(blk_ksm_init_passthrough);
diff --git a/include/linux/keyslot-manager.h b/include/linux/keyslot-manager.h
index 18f3f5346843..323e15dd6fa7 100644
--- a/include/linux/keyslot-manager.h
+++ b/include/linux/keyslot-manager.h
@@ -103,4 +103,6 @@ void blk_ksm_reprogram_all_keys(struct blk_keyslot_manager *ksm);
 
 void blk_ksm_destroy(struct blk_keyslot_manager *ksm);
 
+void blk_ksm_init_passthrough(struct blk_keyslot_manager *ksm);
+
 #endif /* __LINUX_KEYSLOT_MANAGER_H */
-- 
2.30.0.478.g8a0d178c01-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH v5 2/5] block: keyslot-manager: Introduce functions for device mapper support
  2021-02-11 22:53 [PATCH v5 0/5] add support for inline encryption to device mapper Satya Tangirala
  2021-02-11 22:53 ` [PATCH v5 1/5] block: keyslot-manager: Introduce passthrough keyslot manager Satya Tangirala
@ 2021-02-11 22:53 ` Satya Tangirala
  2021-02-11 22:53 ` [PATCH v5 3/5] dm: add support for passing through inline crypto support Satya Tangirala
                   ` (2 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: Satya Tangirala @ 2021-02-11 22:53 UTC (permalink / raw)
  To: linux-block, linux-kernel, dm-devel
  Cc: Jens Axboe, Alasdair Kergon, Mike Snitzer, Eric Biggers, Satya Tangirala

Introduce blk_ksm_update_capabilities() to update the capabilities of
a keyslot manager (ksm) in-place. The pointer to a ksm in a device's
request queue may not be easily replaced, because upper layers like
the filesystem might access it (e.g. for programming keys/checking
capabilities) at the same time the device wants to replace that
request queue's ksm (and free the old ksm's memory). This function
allows the device to update the capabilities of the ksm in its request
queue directly. Devices can safely update the ksm this way without any
synchronization with upper layers *only* if the updated (new) ksm
continues to support all the crypto capabilities that the old ksm did
(see description below for blk_ksm_is_superset() for why this is so).

Also introduce blk_ksm_is_superset() which checks whether one ksm's
capabilities are a (not necessarily strict) superset of another ksm's.
The blk-crypto framework requires that crypto capabilities that were
advertised when a bio was created continue to be supported by the
device until that bio is ended - in practice this probably means that
a device's advertised crypto capabilities can *never* "shrink" (since
there's no synchronization between bio creation and when a device may
want to change its advertised capabilities) - so a previously
advertised crypto capability must always continue to be supported.
This function can be used to check that a new ksm is a valid
replacement for an old ksm.

Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
---
 block/keyslot-manager.c         | 107 ++++++++++++++++++++++++++++++++
 include/linux/keyslot-manager.h |   9 +++
 2 files changed, 116 insertions(+)

diff --git a/block/keyslot-manager.c b/block/keyslot-manager.c
index ac7ce83a76e8..9f9494b80148 100644
--- a/block/keyslot-manager.c
+++ b/block/keyslot-manager.c
@@ -424,6 +424,113 @@ void blk_ksm_unregister(struct request_queue *q)
 	q->ksm = NULL;
 }
 
+/**
+ * blk_ksm_intersect_modes() - restrict supported modes by child device
+ * @parent: The keyslot manager for parent device
+ * @child: The keyslot manager for child device, or NULL
+ *
+ * Clear any crypto mode support bits in @parent that aren't set in @child.
+ * If @child is NULL, then all parent bits are cleared.
+ *
+ * Only use this when setting up the keyslot manager for a layered device,
+ * before it's been exposed yet.
+ */
+void blk_ksm_intersect_modes(struct blk_keyslot_manager *parent,
+			     const struct blk_keyslot_manager *child)
+{
+	if (child) {
+		unsigned int i;
+
+		parent->max_dun_bytes_supported =
+			min(parent->max_dun_bytes_supported,
+			    child->max_dun_bytes_supported);
+		for (i = 0; i < ARRAY_SIZE(child->crypto_modes_supported);
+		     i++) {
+			parent->crypto_modes_supported[i] &=
+				child->crypto_modes_supported[i];
+		}
+	} else {
+		parent->max_dun_bytes_supported = 0;
+		memset(parent->crypto_modes_supported, 0,
+		       sizeof(parent->crypto_modes_supported));
+	}
+}
+EXPORT_SYMBOL_GPL(blk_ksm_intersect_modes);
+
+/**
+ * blk_ksm_is_superset() - Check if a KSM supports a superset of crypto modes
+ *			   and DUN bytes that another KSM supports. Here,
+ *			   "superset" refers to the mathematical meaning of the
+ *			   word - i.e. if two KSMs have the *same* capabilities,
+ *			   they *are* considered supersets of each other.
+ * @ksm_superset: The KSM that we want to verify is a superset
+ * @ksm_subset: The KSM that we want to verify is a subset
+ *
+ * Return: True if @ksm_superset supports a superset of the crypto modes and DUN
+ *	   bytes that @ksm_subset supports.
+ */
+bool blk_ksm_is_superset(struct blk_keyslot_manager *ksm_superset,
+			 struct blk_keyslot_manager *ksm_subset)
+{
+	int i;
+
+	if (!ksm_subset)
+		return true;
+
+	if (!ksm_superset)
+		return false;
+
+	for (i = 0; i < ARRAY_SIZE(ksm_superset->crypto_modes_supported); i++) {
+		if (ksm_subset->crypto_modes_supported[i] &
+		    (~ksm_superset->crypto_modes_supported[i])) {
+			return false;
+		}
+	}
+
+	if (ksm_subset->max_dun_bytes_supported >
+	    ksm_superset->max_dun_bytes_supported) {
+		return false;
+	}
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(blk_ksm_is_superset);
+
+/**
+ * blk_ksm_update_capabilities() - Update the restrictions of a KSM to those of
+ *				   another KSM
+ * @target_ksm: The KSM whose restrictions to update.
+ * @reference_ksm: The KSM to whose restrictions this function will update
+ *		   @target_ksm's restrictions to.
+ *
+ * Blk-crypto requires that crypto capabilities that were
+ * advertised when a bio was created continue to be supported by the
+ * device until that bio is ended. This is turn means that a device cannot
+ * shrink its advertised crypto capabilities without any explicit
+ * synchronization with upper layers. So if there's no such explicit
+ * synchronization, @reference_ksm must support all the crypto capabilities that
+ * @target_ksm does
+ * (i.e. we need blk_ksm_is_superset(@reference_ksm, @target_ksm) == true).
+ *
+ * Note also that as long as the crypto capabilities are being expanded, the
+ * order of updates becoming visible is not important because it's alright
+ * for blk-crypto to see stale values - they only cause blk-crypto to
+ * believe that a crypto capability isn't supported when it actually is (which
+ * might result in blk-crypto-fallback being used if available, or the bio being
+ * failed).
+ */
+void blk_ksm_update_capabilities(struct blk_keyslot_manager *target_ksm,
+				 struct blk_keyslot_manager *reference_ksm)
+{
+	memcpy(target_ksm->crypto_modes_supported,
+	       reference_ksm->crypto_modes_supported,
+	       sizeof(target_ksm->crypto_modes_supported));
+
+	target_ksm->max_dun_bytes_supported =
+				reference_ksm->max_dun_bytes_supported;
+}
+EXPORT_SYMBOL_GPL(blk_ksm_update_capabilities);
+
 /**
  * blk_ksm_init_passthrough() - Init a passthrough keyslot manager
  * @ksm: The keyslot manager to init
diff --git a/include/linux/keyslot-manager.h b/include/linux/keyslot-manager.h
index 323e15dd6fa7..164568f52be7 100644
--- a/include/linux/keyslot-manager.h
+++ b/include/linux/keyslot-manager.h
@@ -103,6 +103,15 @@ void blk_ksm_reprogram_all_keys(struct blk_keyslot_manager *ksm);
 
 void blk_ksm_destroy(struct blk_keyslot_manager *ksm);
 
+void blk_ksm_intersect_modes(struct blk_keyslot_manager *parent,
+			     const struct blk_keyslot_manager *child);
+
 void blk_ksm_init_passthrough(struct blk_keyslot_manager *ksm);
 
+bool blk_ksm_is_superset(struct blk_keyslot_manager *ksm_superset,
+			 struct blk_keyslot_manager *ksm_subset);
+
+void blk_ksm_update_capabilities(struct blk_keyslot_manager *target_ksm,
+				 struct blk_keyslot_manager *reference_ksm);
+
 #endif /* __LINUX_KEYSLOT_MANAGER_H */
-- 
2.30.0.478.g8a0d178c01-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH v5 3/5] dm: add support for passing through inline crypto support
  2021-02-11 22:53 [PATCH v5 0/5] add support for inline encryption to device mapper Satya Tangirala
  2021-02-11 22:53 ` [PATCH v5 1/5] block: keyslot-manager: Introduce passthrough keyslot manager Satya Tangirala
  2021-02-11 22:53 ` [PATCH v5 2/5] block: keyslot-manager: Introduce functions for device mapper support Satya Tangirala
@ 2021-02-11 22:53 ` Satya Tangirala
  2021-02-11 22:53 ` [PATCH v5 4/5] dm: support key eviction from keyslot managers of underlying devices Satya Tangirala
  2021-02-11 22:53 ` [PATCH v5 5/5] dm: set DM_TARGET_PASSES_CRYPTO feature for some targets Satya Tangirala
  4 siblings, 0 replies; 6+ messages in thread
From: Satya Tangirala @ 2021-02-11 22:53 UTC (permalink / raw)
  To: linux-block, linux-kernel, dm-devel
  Cc: Jens Axboe, Alasdair Kergon, Mike Snitzer, Eric Biggers, Satya Tangirala

Update the device-mapper core to support exposing the inline crypto
support of the underlying device(s) through the device-mapper device.

This works by creating a "passthrough keyslot manager" for the dm
device, which declares support for encryption settings which all
underlying devices support.  When a supported setting is used, the bio
cloning code handles cloning the crypto context to the bios for all the
underlying devices.  When an unsupported setting is used, the blk-crypto
fallback is used as usual.

Crypto support on each underlying device is ignored unless the
corresponding dm target opts into exposing it.  This is needed because
for inline crypto to semantically operate on the original bio, the data
must not be transformed by the dm target.  Thus, targets like dm-linear
can expose crypto support of the underlying device, but targets like
dm-crypt can't.  (dm-crypt could use inline crypto itself, though.)

A DM device's table can only be changed if the "new" inline encryption
capabilities are a (*not* necessarily strict) superset of the "old" inline
encryption capabilities.  Attempts to make changes to the table that result
in some inline encryption capability becoming no longer supported will be
rejected.

For the sake of clarity, key eviction from underlying devices will be
handled in a future patch.

Co-developed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
---
 drivers/md/dm-core.h          |  12 +++
 drivers/md/dm-table.c         | 159 ++++++++++++++++++++++++++++++++++
 drivers/md/dm.c               |  18 +++-
 include/linux/device-mapper.h |  12 +++
 4 files changed, 200 insertions(+), 1 deletion(-)

diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h
index 086d293c2b03..f4196ecd6132 100644
--- a/drivers/md/dm-core.h
+++ b/drivers/md/dm-core.h
@@ -13,6 +13,7 @@
 #include <linux/ktime.h>
 #include <linux/genhd.h>
 #include <linux/blk-mq.h>
+#include <linux/keyslot-manager.h>
 
 #include <trace/events/block.h>
 
@@ -162,6 +163,17 @@ struct dm_table {
 	void *event_context;
 
 	struct dm_md_mempools *mempools;
+
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+	/*
+	 * Keyslot manager representing the crypto capabilities of this table.
+	 * This field is only set temporarily, while the table is loaded but
+	 * not swapped in. When the table is swapped in, this field is set to
+	 * NULL after the capabilities are transferred to the request queue of
+	 * the device.
+	 */
+	struct blk_keyslot_manager *ksm;
+#endif
 };
 
 static inline struct completion *dm_get_completion_from_kobject(struct kobject *kobj)
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 4acf2342f7ad..fbaadfc6eed9 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -187,6 +187,8 @@ static void free_devices(struct list_head *devices, struct mapped_device *md)
 	}
 }
 
+static void dm_table_destroy_keyslot_manager(struct dm_table *t);
+
 void dm_table_destroy(struct dm_table *t)
 {
 	unsigned int i;
@@ -215,6 +217,8 @@ void dm_table_destroy(struct dm_table *t)
 
 	dm_free_md_mempools(t->mempools);
 
+	dm_table_destroy_keyslot_manager(t);
+
 	kfree(t);
 }
 
@@ -1203,6 +1207,154 @@ static int dm_table_register_integrity(struct dm_table *t)
 	return 0;
 }
 
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+
+struct dm_keyslot_manager {
+	struct blk_keyslot_manager ksm;
+	struct mapped_device *md;
+};
+
+static int device_intersect_crypto_modes(struct dm_target *ti,
+					 struct dm_dev *dev, sector_t start,
+					 sector_t len, void *data)
+{
+	struct blk_keyslot_manager *parent = data;
+	struct blk_keyslot_manager *child = bdev_get_queue(dev->bdev)->ksm;
+
+	blk_ksm_intersect_modes(parent, child);
+	return 0;
+}
+
+void dm_destroy_keyslot_manager(struct blk_keyslot_manager *ksm)
+{
+	struct dm_keyslot_manager *dksm = container_of(ksm,
+						       struct dm_keyslot_manager,
+						       ksm);
+
+	if (!ksm)
+		return;
+
+	blk_ksm_destroy(ksm);
+	kfree(dksm);
+}
+
+static void dm_table_destroy_keyslot_manager(struct dm_table *t)
+{
+	dm_destroy_keyslot_manager(t->ksm);
+	t->ksm = NULL;
+}
+
+/*
+ * Initializes t->ksm with a keyslot manager that represents the common set of
+ * crypto capabilities of the devices described by the dm_table. However, if the
+ * constructed keyslot manager does not support a superset of the crypto
+ * capabilities supported by the current keyslot manager of the mapped_device,
+ * it returns an error instead, since we don't support restricting crypto
+ * capabilities on table changes. Finally, if the constructed keyslot manager
+ * doesn't actually support any crypto modes at all, it set @t->ksm to NULL
+ * (since a NULL ksm represents support for no capabilities) and returns 0
+ * (representing success).
+ */
+static int
+dm_table_construct_keyslot_manager(struct dm_table *t)
+{
+	struct dm_keyslot_manager *dksm;
+	struct blk_keyslot_manager *ksm;
+	struct dm_target *ti;
+	unsigned int i;
+	bool ksm_is_empty = true;
+
+	dksm = kmalloc(sizeof(*dksm), GFP_KERNEL);
+	if (!dksm)
+		return -ENOMEM;
+	dksm->md = t->md;
+
+	ksm = &dksm->ksm;
+	blk_ksm_init_passthrough(ksm);
+	ksm->max_dun_bytes_supported = UINT_MAX;
+	memset(ksm->crypto_modes_supported, 0xFF,
+	       sizeof(ksm->crypto_modes_supported));
+
+	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+		ti = dm_table_get_target(t, i);
+
+		if (!dm_target_passes_crypto(ti->type)) {
+			blk_ksm_intersect_modes(ksm, NULL);
+			break;
+		}
+		if (!ti->type->iterate_devices)
+			continue;
+		ti->type->iterate_devices(ti, device_intersect_crypto_modes,
+					  ksm);
+	}
+
+	if (t->md->queue && !blk_ksm_is_superset(ksm, t->md->queue->ksm)) {
+		DMWARN("Inline encryption capabilities of new DM table were more restrictive than the old table's. This is not supported!");
+		dm_destroy_keyslot_manager(ksm);
+		return -EINVAL;
+	}
+
+	/*
+	 * If the new KSM doesn't actually support any crypto modes, we may as
+	 * well represent it with a NULL ksm.
+	 */
+	ksm_is_empty = true;
+	for (i = 0; i < ARRAY_SIZE(ksm->crypto_modes_supported); i++) {
+		if (ksm->crypto_modes_supported[i]) {
+			ksm_is_empty = false;
+			break;
+		}
+	}
+
+	if (ksm_is_empty) {
+		dm_destroy_keyslot_manager(ksm);
+		ksm = NULL;
+	}
+
+	t->ksm = ksm;
+
+	return 0;
+}
+
+static void dm_update_keyslot_manager(struct request_queue *q,
+				      struct dm_table *t)
+{
+	if (!t->ksm)
+		return;
+
+	/* Make the ksm less restrictive */
+	if (!q->ksm) {
+		blk_ksm_register(t->ksm, q);
+	} else {
+		blk_ksm_update_capabilities(q->ksm, t->ksm);
+		dm_destroy_keyslot_manager(t->ksm);
+	}
+	t->ksm = NULL;
+}
+
+#else /* CONFIG_BLK_INLINE_ENCRYPTION */
+
+static int
+dm_table_construct_keyslot_manager(struct dm_table *t)
+{
+	return 0;
+}
+
+void dm_destroy_keyslot_manager(struct blk_keyslot_manager *ksm)
+{
+}
+
+static void dm_table_destroy_keyslot_manager(struct dm_table *t)
+{
+}
+
+static void dm_update_keyslot_manager(struct request_queue *q,
+				      struct dm_table *t)
+{
+}
+
+#endif /* !CONFIG_BLK_INLINE_ENCRYPTION */
+
 /*
  * Prepares the table for use by building the indices,
  * setting the type, and allocating mempools.
@@ -1229,6 +1381,12 @@ int dm_table_complete(struct dm_table *t)
 		return r;
 	}
 
+	r = dm_table_construct_keyslot_manager(t);
+	if (r) {
+		DMERR("could not construct keyslot manager.");
+		return r;
+	}
+
 	r = dm_table_alloc_md_mempools(t, t->md);
 	if (r)
 		DMERR("unable to allocate mempools");
@@ -1891,6 +2049,7 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
 	}
 #endif
 
+	dm_update_keyslot_manager(q, t);
 	blk_queue_update_readahead(q);
 }
 
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 7bac564f3faa..ee0434764941 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -28,6 +28,7 @@
 #include <linux/refcount.h>
 #include <linux/part_stat.h>
 #include <linux/blk-crypto.h>
+#include <linux/keyslot-manager.h>
 
 #define DM_MSG_PREFIX "core"
 
@@ -1718,6 +1719,19 @@ static const struct dax_operations dm_dax_ops;
 
 static void dm_wq_work(struct work_struct *work);
 
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+static void dm_queue_destroy_keyslot_manager(struct request_queue *q)
+{
+	dm_destroy_keyslot_manager(q->ksm);
+}
+
+#else /* CONFIG_BLK_INLINE_ENCRYPTION */
+
+static inline void dm_queue_destroy_keyslot_manager(struct request_queue *q)
+{
+}
+#endif /* !CONFIG_BLK_INLINE_ENCRYPTION */
+
 static void cleanup_mapped_device(struct mapped_device *md)
 {
 	if (md->wq)
@@ -1739,8 +1753,10 @@ static void cleanup_mapped_device(struct mapped_device *md)
 		put_disk(md->disk);
 	}
 
-	if (md->queue)
+	if (md->queue) {
+		dm_queue_destroy_keyslot_manager(md->queue);
 		blk_cleanup_queue(md->queue);
+	}
 
 	cleanup_srcu_struct(&md->io_barrier);
 
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 61a66fb8ebb3..f7198b492fea 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -257,6 +257,13 @@ struct target_type {
 #define DM_TARGET_NOWAIT		0x00000080
 #define dm_target_supports_nowait(type) ((type)->features & DM_TARGET_NOWAIT)
 
+/*
+ * The target supports exposing the underlying device's inline encryption
+ * capabilities
+ */
+#define DM_TARGET_PASSES_CRYPTO		0x00000100
+#define dm_target_passes_crypto(type) ((type)->features & DM_TARGET_PASSES_CRYPTO)
+
 struct dm_target {
 	struct dm_table *table;
 	struct target_type *type;
@@ -533,6 +540,11 @@ void dm_table_run_md_queue_async(struct dm_table *t);
 struct dm_table *dm_swap_table(struct mapped_device *md,
 			       struct dm_table *t);
 
+/*
+ * Table keyslot manager functions
+ */
+void dm_destroy_keyslot_manager(struct blk_keyslot_manager *ksm);
+
 /*
  * A wrapper around vmalloc.
  */
-- 
2.30.0.478.g8a0d178c01-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH v5 4/5] dm: support key eviction from keyslot managers of underlying devices
  2021-02-11 22:53 [PATCH v5 0/5] add support for inline encryption to device mapper Satya Tangirala
                   ` (2 preceding siblings ...)
  2021-02-11 22:53 ` [PATCH v5 3/5] dm: add support for passing through inline crypto support Satya Tangirala
@ 2021-02-11 22:53 ` Satya Tangirala
  2021-02-11 22:53 ` [PATCH v5 5/5] dm: set DM_TARGET_PASSES_CRYPTO feature for some targets Satya Tangirala
  4 siblings, 0 replies; 6+ messages in thread
From: Satya Tangirala @ 2021-02-11 22:53 UTC (permalink / raw)
  To: linux-block, linux-kernel, dm-devel
  Cc: Jens Axboe, Alasdair Kergon, Mike Snitzer, Eric Biggers, Satya Tangirala

Now that device mapper supports inline encryption, add the ability to
evict keys from all underlying devices. When an upper layer requests
a key eviction, we simply iterate through all underlying devices
and evict that key from each device.

Co-developed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
---
 block/blk-crypto.c    |  1 +
 drivers/md/dm-table.c | 53 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+)

diff --git a/block/blk-crypto.c b/block/blk-crypto.c
index 5da43f0973b4..c2be8f15006c 100644
--- a/block/blk-crypto.c
+++ b/block/blk-crypto.c
@@ -409,3 +409,4 @@ int blk_crypto_evict_key(struct request_queue *q,
 	 */
 	return blk_crypto_fallback_evict_key(key);
 }
+EXPORT_SYMBOL_GPL(blk_crypto_evict_key);
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index fbaadfc6eed9..b036a349aaad 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1214,6 +1214,58 @@ struct dm_keyslot_manager {
 	struct mapped_device *md;
 };
 
+struct dm_keyslot_evict_args {
+	const struct blk_crypto_key *key;
+	int err;
+};
+
+static int dm_keyslot_evict_callback(struct dm_target *ti, struct dm_dev *dev,
+				     sector_t start, sector_t len, void *data)
+{
+	struct dm_keyslot_evict_args *args = data;
+	int err;
+
+	err = blk_crypto_evict_key(bdev_get_queue(dev->bdev), args->key);
+	if (!args->err)
+		args->err = err;
+	/* Always try to evict the key from all devices. */
+	return 0;
+}
+
+/*
+ * When an inline encryption key is evicted from a device-mapper device, evict
+ * it from all the underlying devices.
+ */
+static int dm_keyslot_evict(struct blk_keyslot_manager *ksm,
+			    const struct blk_crypto_key *key, unsigned int slot)
+{
+	struct dm_keyslot_manager *dksm = container_of(ksm,
+						       struct dm_keyslot_manager,
+						       ksm);
+	struct mapped_device *md = dksm->md;
+	struct dm_keyslot_evict_args args = { key };
+	struct dm_table *t;
+	int srcu_idx;
+	int i;
+	struct dm_target *ti;
+
+	t = dm_get_live_table(md, &srcu_idx);
+	if (!t)
+		return 0;
+	for (i = 0; i < dm_table_get_num_targets(t); i++) {
+		ti = dm_table_get_target(t, i);
+		if (!ti->type->iterate_devices)
+			continue;
+		ti->type->iterate_devices(ti, dm_keyslot_evict_callback, &args);
+	}
+	dm_put_live_table(md, srcu_idx);
+	return args.err;
+}
+
+static struct blk_ksm_ll_ops dm_ksm_ll_ops = {
+	.keyslot_evict = dm_keyslot_evict,
+};
+
 static int device_intersect_crypto_modes(struct dm_target *ti,
 					 struct dm_dev *dev, sector_t start,
 					 sector_t len, void *data)
@@ -1271,6 +1323,7 @@ dm_table_construct_keyslot_manager(struct dm_table *t)
 
 	ksm = &dksm->ksm;
 	blk_ksm_init_passthrough(ksm);
+	ksm->ksm_ll_ops = dm_ksm_ll_ops;
 	ksm->max_dun_bytes_supported = UINT_MAX;
 	memset(ksm->crypto_modes_supported, 0xFF,
 	       sizeof(ksm->crypto_modes_supported));
-- 
2.30.0.478.g8a0d178c01-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread

* [PATCH v5 5/5] dm: set DM_TARGET_PASSES_CRYPTO feature for some targets
  2021-02-11 22:53 [PATCH v5 0/5] add support for inline encryption to device mapper Satya Tangirala
                   ` (3 preceding siblings ...)
  2021-02-11 22:53 ` [PATCH v5 4/5] dm: support key eviction from keyslot managers of underlying devices Satya Tangirala
@ 2021-02-11 22:53 ` Satya Tangirala
  4 siblings, 0 replies; 6+ messages in thread
From: Satya Tangirala @ 2021-02-11 22:53 UTC (permalink / raw)
  To: linux-block, linux-kernel, dm-devel
  Cc: Jens Axboe, Alasdair Kergon, Mike Snitzer, Eric Biggers, Satya Tangirala

dm-linear and dm-flakey obviously can pass through inline crypto support.

Co-developed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Satya Tangirala <satyat@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
---
 drivers/md/dm-flakey.c | 4 +++-
 drivers/md/dm-linear.c | 5 +++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index a2cc9e45cbba..30c6bc151213 100644
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -482,8 +482,10 @@ static struct target_type flakey_target = {
 	.name   = "flakey",
 	.version = {1, 5, 0},
 #ifdef CONFIG_BLK_DEV_ZONED
-	.features = DM_TARGET_ZONED_HM,
+	.features = DM_TARGET_ZONED_HM | DM_TARGET_PASSES_CRYPTO,
 	.report_zones = flakey_report_zones,
+#else
+	.features = DM_TARGET_PASSES_CRYPTO,
 #endif
 	.module = THIS_MODULE,
 	.ctr    = flakey_ctr,
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 00774b5d7668..fc9c4272c10d 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -229,10 +229,11 @@ static struct target_type linear_target = {
 	.version = {1, 4, 0},
 #ifdef CONFIG_BLK_DEV_ZONED
 	.features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT |
-		    DM_TARGET_ZONED_HM,
+		    DM_TARGET_ZONED_HM | DM_TARGET_PASSES_CRYPTO,
 	.report_zones = linear_report_zones,
 #else
-	.features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT,
+	.features = DM_TARGET_PASSES_INTEGRITY | DM_TARGET_NOWAIT |
+		    DM_TARGET_PASSES_CRYPTO,
 #endif
 	.module = THIS_MODULE,
 	.ctr    = linear_ctr,
-- 
2.30.0.478.g8a0d178c01-goog


^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2021-02-11 22:55 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-11 22:53 [PATCH v5 0/5] add support for inline encryption to device mapper Satya Tangirala
2021-02-11 22:53 ` [PATCH v5 1/5] block: keyslot-manager: Introduce passthrough keyslot manager Satya Tangirala
2021-02-11 22:53 ` [PATCH v5 2/5] block: keyslot-manager: Introduce functions for device mapper support Satya Tangirala
2021-02-11 22:53 ` [PATCH v5 3/5] dm: add support for passing through inline crypto support Satya Tangirala
2021-02-11 22:53 ` [PATCH v5 4/5] dm: support key eviction from keyslot managers of underlying devices Satya Tangirala
2021-02-11 22:53 ` [PATCH v5 5/5] dm: set DM_TARGET_PASSES_CRYPTO feature for some targets Satya Tangirala

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