[2/3] dm: add support for passing through inline crypto support

Message ID	20200909234422.76194-3-satyat@google.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <SRS0=/Scz=CT=vger.kernel.org=linux-block-owner@kernel.org> Date: Wed, 9 Sep 2020 23:44:21 +0000 In-Reply-To: <20200909234422.76194-1-satyat@google.com> Message-Id: <20200909234422.76194-3-satyat@google.com> Mime-Version: 1.0 References: <20200909234422.76194-1-satyat@google.com> Subject: [PATCH 2/3] dm: add support for passing through inline crypto support From: Satya Tangirala <satyat@google.com> To: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, dm-devel@redhat.com Cc: Jens Axboe <axboe@kernel.dk>, Alasdair Kergon <agk@redhat.com>, Mike Snitzer <snitzer@redhat.com>, Eric Biggers <ebiggers@google.com>, Satya Tangirala <satyat@google.com> Content-Type: text/plain; charset="UTF-8" Sender: linux-block-owner@vger.kernel.org Precedence: bulk
Series	add support for inline encryption to device mapper \| expand [0/3] add support for inline encryption to device mapper [1/3] block: keyslot-manager: Introduce passthrough keyslot manager [2/3] dm: add support for passing through inline crypto support [3/3] dm: enable may_passthrough_inline_crypto on some targets

diff --git a/block/blk-crypto.c b/block/blk-crypto.c index 2d5e60023b08..33555cf0e3e7 100644 --- a/block/blk-crypto.c +++ b/block/blk-crypto.c @@ -402,3 +402,4 @@ 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/block/keyslot-manager.c b/block/keyslot-manager.c index 60ac406d54b9..e0f776c38d8a 100644 --- a/block/keyslot-manager.c +++ b/block/keyslot-manager.c @@ -416,6 +416,40 @@ void blk_ksm_unregister(struct request_queue *q) { q->ksm = NULL; } +EXPORT_SYMBOL_GPL(blk_ksm_unregister); + +/** + * 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_init_passthrough() - Init a passthrough keyslot manager diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h index c4ef1fceead6..4542050eebfc 100644 --- a/drivers/md/dm-core.h +++ b/drivers/md/dm-core.h @@ -12,6 +12,7 @@ #include <linux/kthread.h> #include <linux/ktime.h> #include <linux/blk-mq.h> +#include <linux/keyslot-manager.h> #include <trace/events/block.h> @@ -49,6 +50,9 @@ struct mapped_device { int numa_node_id; struct request_queue *queue; +#ifdef CONFIG_BLK_INLINE_ENCRYPTION + struct blk_keyslot_manager ksm; +#endif atomic_t holders; atomic_t open_count; diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 5edc3079e7c1..09ad65e582a8 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -21,6 +21,8 @@ #include <linux/blk-mq.h> #include <linux/mount.h> #include <linux/dax.h> +#include <linux/bio.h> +#include <linux/keyslot-manager.h> #define DM_MSG_PREFIX "table" @@ -1579,6 +1581,54 @@ static void dm_table_verify_integrity(struct dm_table *t) } } +#ifdef CONFIG_BLK_INLINE_ENCRYPTION +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; +} + +/* + * Update the inline crypto modes supported by 'q->ksm' to be the intersection + * of the modes supported by all targets in the table. + * + * For any mode to be supported at all, all targets must have explicitly + * declared that they can pass through inline crypto support. For a particular + * mode to be supported, all underlying devices must also support it. + * + * Assume that 'q->ksm' initially declares all modes to be supported. + */ +static void dm_calculate_supported_crypto_modes(struct dm_table *t, + struct request_queue *q) +{ + struct dm_target *ti; + unsigned int i; + + for (i = 0; i < dm_table_get_num_targets(t); i++) { + ti = dm_table_get_target(t, i); + + if (!ti->may_passthrough_inline_crypto) { + blk_ksm_intersect_modes(q->ksm, NULL); + return; + } + if (!ti->type->iterate_devices) + continue; + ti->type->iterate_devices(ti, device_intersect_crypto_modes, + q->ksm); + } +} +#else /* CONFIG_BLK_INLINE_ENCRYPTION */ +static inline void dm_calculate_supported_crypto_modes(struct dm_table *t, + struct request_queue *q) +{ +} +#endif /* !CONFIG_BLK_INLINE_ENCRYPTION */ + static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { @@ -1895,6 +1945,8 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, dm_table_verify_integrity(t); + dm_calculate_supported_crypto_modes(t, q); + /* * Some devices don't use blk_integrity but still want stable pages * because they do their own checksumming. diff --git a/drivers/md/dm.c b/drivers/md/dm.c index fb0255d25e4b..9cfc2b63323d 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" @@ -1869,6 +1870,8 @@ static const struct dax_operations dm_dax_ops; static void dm_wq_work(struct work_struct *work); +static void dm_destroy_inline_encryption(struct request_queue *q); + static void cleanup_mapped_device(struct mapped_device *md) { if (md->wq) @@ -1890,8 +1893,10 @@ static void cleanup_mapped_device(struct mapped_device *md) put_disk(md->disk); } - if (md->queue) + if (md->queue) { + dm_destroy_inline_encryption(md->queue); blk_cleanup_queue(md->queue); + } cleanup_srcu_struct(&md->io_barrier); @@ -2253,6 +2258,88 @@ struct queue_limits *dm_get_queue_limits(struct mapped_device *md) } EXPORT_SYMBOL_GPL(dm_get_queue_limits); +#ifdef CONFIG_BLK_INLINE_ENCRYPTION +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 mapped_device *md = container_of(ksm, struct mapped_device, ksm); + 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 void dm_init_inline_encryption(struct mapped_device *md) +{ + blk_ksm_init_passthrough(&md->ksm); + md->ksm.ksm_ll_ops = dm_ksm_ll_ops; + + /* + * Initially declare support for all crypto settings. Anything + * unsupported by a child device will be removed later when calculating + * the device restrictions. + */ + md->ksm.max_dun_bytes_supported = UINT_MAX; + memset(md->ksm.crypto_modes_supported, 0xFF, + sizeof(md->ksm.crypto_modes_supported)); + + blk_ksm_register(&md->ksm, md->queue); +} + +static void dm_destroy_inline_encryption(struct request_queue *q) +{ + blk_ksm_destroy(q->ksm); + blk_ksm_unregister(q); +} +#else /* CONFIG_BLK_INLINE_ENCRYPTION */ +static inline void dm_init_inline_encryption(struct mapped_device *md) +{ +} + +static inline void dm_destroy_inline_encryption(struct request_queue *q) +{ +} +#endif /* !CONFIG_BLK_INLINE_ENCRYPTION */ + /* * Setup the DM device's queue based on md's type */ @@ -2284,6 +2371,9 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t) DMERR("Cannot calculate initial queue limits"); return r; } + + dm_init_inline_encryption(md); + dm_table_set_restrictions(t, md->queue, &limits); blk_register_queue(md->disk); diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index 93096e524e43..104f364866f9 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -320,6 +320,12 @@ struct dm_target { * whether or not its underlying devices have support. */ bool discards_supported:1; + + /* + * Set if inline crypto capabilities from this target's underlying + * device(s) can be exposed via the device-mapper device. + */ + bool may_passthrough_inline_crypto:1; }; void *dm_per_bio_data(struct bio *bio, size_t data_size); diff --git a/include/linux/keyslot-manager.h b/include/linux/keyslot-manager.h index 323e15dd6fa7..bfe7f35da4a8 100644 --- a/include/linux/keyslot-manager.h +++ b/include/linux/keyslot-manager.h @@ -9,6 +9,8 @@ #include <linux/bio.h> #include <linux/blk-crypto.h> +#ifdef CONFIG_BLK_INLINE_ENCRYPTION + struct blk_keyslot_manager; /** @@ -103,6 +105,11 @@ 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); +#endif /* CONFIG_BLK_INLINE_ENCRYPTION */ + #endif /* __LINUX_KEYSLOT_MANAGER_H */

[2/3] dm: add support for passing through inline crypto support

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