From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/block/blk-crypto.c | 478 ++++++++++++++++++++++++++++++++++++++---------------------
1 files changed, 310 insertions(+), 168 deletions(-)
diff --git a/kernel/block/blk-crypto.c b/kernel/block/blk-crypto.c
index e07a37c..ccb2dc5 100644
--- a/kernel/block/blk-crypto.c
+++ b/kernel/block/blk-crypto.c
@@ -9,11 +9,12 @@
#define pr_fmt(fmt) "blk-crypto: " fmt
-#include <linux/blk-crypto.h>
+#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/keyslot-manager.h>
-#include <linux/random.h>
-#include <linux/siphash.h>
+#include <linux/module.h>
+#include <linux/ratelimit.h>
+#include <linux/slab.h>
#include "blk-crypto-internal.h"
@@ -35,139 +36,273 @@
},
};
-/* Check that all I/O segments are data unit aligned */
-static int bio_crypt_check_alignment(struct bio *bio)
+/*
+ * This number needs to be at least (the number of threads doing IO
+ * concurrently) * (maximum recursive depth of a bio), so that we don't
+ * deadlock on crypt_ctx allocations. The default is chosen to be the same
+ * as the default number of post read contexts in both EXT4 and F2FS.
+ */
+static int num_prealloc_crypt_ctxs = 128;
+
+module_param(num_prealloc_crypt_ctxs, int, 0444);
+MODULE_PARM_DESC(num_prealloc_crypt_ctxs,
+ "Number of bio crypto contexts to preallocate");
+
+static struct kmem_cache *bio_crypt_ctx_cache;
+static mempool_t *bio_crypt_ctx_pool;
+
+static int __init bio_crypt_ctx_init(void)
+{
+ size_t i;
+
+ bio_crypt_ctx_cache = KMEM_CACHE(bio_crypt_ctx, 0);
+ if (!bio_crypt_ctx_cache)
+ goto out_no_mem;
+
+ bio_crypt_ctx_pool = mempool_create_slab_pool(num_prealloc_crypt_ctxs,
+ bio_crypt_ctx_cache);
+ if (!bio_crypt_ctx_pool)
+ goto out_no_mem;
+
+ /* This is assumed in various places. */
+ BUILD_BUG_ON(BLK_ENCRYPTION_MODE_INVALID != 0);
+
+ /* Sanity check that no algorithm exceeds the defined limits. */
+ for (i = 0; i < BLK_ENCRYPTION_MODE_MAX; i++) {
+ BUG_ON(blk_crypto_modes[i].keysize > BLK_CRYPTO_MAX_KEY_SIZE);
+ BUG_ON(blk_crypto_modes[i].ivsize > BLK_CRYPTO_MAX_IV_SIZE);
+ }
+
+ return 0;
+out_no_mem:
+ panic("Failed to allocate mem for bio crypt ctxs\n");
+}
+subsys_initcall(bio_crypt_ctx_init);
+
+void bio_crypt_set_ctx(struct bio *bio, const struct blk_crypto_key *key,
+ const u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE], gfp_t gfp_mask)
+{
+ struct bio_crypt_ctx *bc;
+
+ /*
+ * The caller must use a gfp_mask that contains __GFP_DIRECT_RECLAIM so
+ * that the mempool_alloc() can't fail.
+ */
+ WARN_ON_ONCE(!(gfp_mask & __GFP_DIRECT_RECLAIM));
+
+ bc = mempool_alloc(bio_crypt_ctx_pool, gfp_mask);
+
+ bc->bc_key = key;
+ memcpy(bc->bc_dun, dun, sizeof(bc->bc_dun));
+
+ bio->bi_crypt_context = bc;
+}
+EXPORT_SYMBOL_GPL(bio_crypt_set_ctx);
+
+void __bio_crypt_free_ctx(struct bio *bio)
+{
+ mempool_free(bio->bi_crypt_context, bio_crypt_ctx_pool);
+ bio->bi_crypt_context = NULL;
+}
+
+int __bio_crypt_clone(struct bio *dst, struct bio *src, gfp_t gfp_mask)
+{
+ dst->bi_crypt_context = mempool_alloc(bio_crypt_ctx_pool, gfp_mask);
+ if (!dst->bi_crypt_context)
+ return -ENOMEM;
+ *dst->bi_crypt_context = *src->bi_crypt_context;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__bio_crypt_clone);
+
+/* Increments @dun by @inc, treating @dun as a multi-limb integer. */
+void bio_crypt_dun_increment(u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
+ unsigned int inc)
+{
+ int i;
+
+ for (i = 0; inc && i < BLK_CRYPTO_DUN_ARRAY_SIZE; i++) {
+ dun[i] += inc;
+ /*
+ * If the addition in this limb overflowed, then we need to
+ * carry 1 into the next limb. Else the carry is 0.
+ */
+ if (dun[i] < inc)
+ inc = 1;
+ else
+ inc = 0;
+ }
+}
+
+void __bio_crypt_advance(struct bio *bio, unsigned int bytes)
+{
+ struct bio_crypt_ctx *bc = bio->bi_crypt_context;
+
+ bio_crypt_dun_increment(bc->bc_dun,
+ bytes >> bc->bc_key->data_unit_size_bits);
+}
+
+/*
+ * Returns true if @bc->bc_dun plus @bytes converted to data units is equal to
+ * @next_dun, treating the DUNs as multi-limb integers.
+ */
+bool bio_crypt_dun_is_contiguous(const struct bio_crypt_ctx *bc,
+ unsigned int bytes,
+ const u64 next_dun[BLK_CRYPTO_DUN_ARRAY_SIZE])
+{
+ int i;
+ unsigned int carry = bytes >> bc->bc_key->data_unit_size_bits;
+
+ for (i = 0; i < BLK_CRYPTO_DUN_ARRAY_SIZE; i++) {
+ if (bc->bc_dun[i] + carry != next_dun[i])
+ return false;
+ /*
+ * If the addition in this limb overflowed, then we need to
+ * carry 1 into the next limb. Else the carry is 0.
+ */
+ if ((bc->bc_dun[i] + carry) < carry)
+ carry = 1;
+ else
+ carry = 0;
+ }
+
+ /* If the DUN wrapped through 0, don't treat it as contiguous. */
+ return carry == 0;
+}
+
+/*
+ * Checks that two bio crypt contexts are compatible - i.e. that
+ * they are mergeable except for data_unit_num continuity.
+ */
+static bool bio_crypt_ctx_compatible(struct bio_crypt_ctx *bc1,
+ struct bio_crypt_ctx *bc2)
+{
+ if (!bc1)
+ return !bc2;
+
+ return bc2 && bc1->bc_key == bc2->bc_key;
+}
+
+bool bio_crypt_rq_ctx_compatible(struct request *rq, struct bio *bio)
+{
+ return bio_crypt_ctx_compatible(rq->crypt_ctx, bio->bi_crypt_context);
+}
+
+/*
+ * Checks that two bio crypt contexts are compatible, and also
+ * that their data_unit_nums are continuous (and can hence be merged)
+ * in the order @bc1 followed by @bc2.
+ */
+bool bio_crypt_ctx_mergeable(struct bio_crypt_ctx *bc1, unsigned int bc1_bytes,
+ struct bio_crypt_ctx *bc2)
+{
+ if (!bio_crypt_ctx_compatible(bc1, bc2))
+ return false;
+
+ return !bc1 || bio_crypt_dun_is_contiguous(bc1, bc1_bytes, bc2->bc_dun);
+}
+
+/* Check that all I/O segments are data unit aligned. */
+static bool bio_crypt_check_alignment(struct bio *bio)
{
const unsigned int data_unit_size =
- bio->bi_crypt_context->bc_key->data_unit_size;
+ bio->bi_crypt_context->bc_key->crypto_cfg.data_unit_size;
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 false;
}
- return 0;
+
+ return true;
+}
+
+blk_status_t __blk_crypto_rq_get_keyslot(struct request *rq)
+{
+ return blk_ksm_get_slot_for_key(rq->q->ksm, rq->crypt_ctx->bc_key,
+ &rq->crypt_keyslot);
+}
+
+void __blk_crypto_rq_put_keyslot(struct request *rq)
+{
+ blk_ksm_put_slot(rq->crypt_keyslot);
+ rq->crypt_keyslot = NULL;
+}
+
+void __blk_crypto_free_request(struct request *rq)
+{
+ /* The keyslot, if one was needed, should have been released earlier. */
+ if (WARN_ON_ONCE(rq->crypt_keyslot))
+ __blk_crypto_rq_put_keyslot(rq);
+
+ mempool_free(rq->crypt_ctx, bio_crypt_ctx_pool);
+ rq->crypt_ctx = NULL;
}
/**
- * blk_crypto_submit_bio - handle submitting bio for inline encryption
+ * __blk_crypto_bio_prep - Prepare 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 crypto API fallback.
+ * If the bio crypt context provided for the bio is supported by the underlying
+ * device's inline encryption hardware, do nothing.
*
- * When the crypto API fallback is used for encryption, blk-crypto may choose to
- * split the bio into 2 - the first one that will continue to be processed and
- * the second one that will be resubmitted via generic_make_request.
- * A bounce bio will be allocated to encrypt the contents of the aforementioned
- * "first one", and *bio_ptr will be updated to this bounce bio.
+ * Otherwise, try to perform en/decryption for this bio by falling back to the
+ * kernel crypto API. When the crypto API fallback is used for encryption,
+ * blk-crypto may choose to split the bio into 2 - the first one that will
+ * continue to be processed and the second one that will be resubmitted via
+ * submit_bio_noacct. A bounce bio will be allocated to encrypt the contents
+ * of the aforementioned "first one", and *bio_ptr will be updated to this
+ * bounce bio.
*
- * Return: 0 if bio submission should continue; nonzero if bio_endio() was
- * already called so bio submission should abort.
+ * Caller must ensure bio has bio_crypt_ctx.
+ *
+ * Return: true on success; false on error (and bio->bi_status will be set
+ * appropriately, and bio_endio() will have been called so bio
+ * submission should abort).
*/
-int blk_crypto_submit_bio(struct bio **bio_ptr)
+bool __blk_crypto_bio_prep(struct bio **bio_ptr)
{
struct bio *bio = *bio_ptr;
- struct request_queue *q;
- struct bio_crypt_ctx *bc = bio->bi_crypt_context;
- int err;
+ const struct blk_crypto_key *bc_key = bio->bi_crypt_context->bc_key;
- if (!bc || !bio_has_data(bio))
- return 0;
+ /* Error if bio has no data. */
+ if (WARN_ON_ONCE(!bio_has_data(bio))) {
+ bio->bi_status = BLK_STS_IOERR;
+ goto fail;
+ }
+
+ if (!bio_crypt_check_alignment(bio)) {
+ bio->bi_status = BLK_STS_IOERR;
+ goto fail;
+ }
/*
- * When a read bio is marked for fallback decryption, its bi_iter is
- * saved so that when we decrypt the bio later, we know what part of it
- * was marked for fallback 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)
+ * Success if device supports the encryption context, or if we succeeded
+ * in falling back to the crypto API.
*/
- if (bio_crypt_fallback_crypted(bc))
- return 0;
-
- err = bio_crypt_check_alignment(bio);
- if (err) {
- bio->bi_status = BLK_STS_IOERR;
- goto out;
- }
-
- q = bio->bi_disk->queue;
-
- if (bc->bc_ksm) {
- /* Key already programmed into device? */
- if (q->ksm == bc->bc_ksm)
- return 0;
-
- /* Nope, release the existing keyslot. */
- bio_crypt_ctx_release_keyslot(bc);
- }
-
- /* Get device keyslot if supported */
- if (keyslot_manager_crypto_mode_supported(q->ksm,
- bc->bc_key->crypto_mode,
- blk_crypto_key_dun_bytes(bc->bc_key),
- bc->bc_key->data_unit_size,
- bc->bc_key->is_hw_wrapped)) {
- err = bio_crypt_ctx_acquire_keyslot(bc, q->ksm);
- if (!err)
- return 0;
-
- pr_warn_once("Failed to acquire keyslot for %s (err=%d). Falling back to crypto API.\n",
- bio->bi_disk->disk_name, err);
- }
-
- /* Fallback to crypto API */
- err = blk_crypto_fallback_submit_bio(bio_ptr);
- if (err)
- goto out;
-
- return 0;
-out:
- bio_endio(*bio_ptr);
- 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 crypto API 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 by the crypto API, 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)
-{
- struct bio_crypt_ctx *bc = bio->bi_crypt_context;
-
- if (!bc)
+ if (blk_ksm_crypto_cfg_supported(bio->bi_disk->queue->ksm,
+ &bc_key->crypto_cfg))
return true;
- if (bio_crypt_fallback_crypted(bc)) {
- /*
- * The only bios who's crypto is handled by the blk-crypto
- * fallback when they reach here are those with
- * bio_data_dir(bio) == READ, since WRITE bios that are
- * encrypted by the crypto API fallback are handled by
- * blk_crypto_encrypt_endio().
- */
- return !blk_crypto_queue_decrypt_bio(bio);
+ if (blk_crypto_fallback_bio_prep(bio_ptr))
+ return true;
+fail:
+ bio_endio(*bio_ptr);
+ return false;
+}
+
+int __blk_crypto_rq_bio_prep(struct request *rq, struct bio *bio,
+ gfp_t gfp_mask)
+{
+ if (!rq->crypt_ctx) {
+ rq->crypt_ctx = mempool_alloc(bio_crypt_ctx_pool, gfp_mask);
+ if (!rq->crypt_ctx)
+ return -ENOMEM;
}
-
- if (bc->bc_keyslot >= 0)
- bio_crypt_ctx_release_keyslot(bc);
-
- return true;
+ *rq->crypt_ctx = *bio->bi_crypt_context;
+ return 0;
}
/**
@@ -185,8 +320,8 @@
* key is used
* @data_unit_size: the data unit size to use for en/decryption
*
- * Return: The blk_crypto_key that was prepared, or an ERR_PTR() on error. When
- * done using the key, it must be freed with blk_crypto_free_key().
+ * Return: 0 on success, -errno on failure. The caller is responsible for
+ * zeroizing both blk_key and raw_key when done with them.
*/
int blk_crypto_init_key(struct blk_crypto_key *blk_key,
const u8 *raw_key, unsigned int raw_key_size,
@@ -196,8 +331,6 @@
unsigned int data_unit_size)
{
const struct blk_crypto_mode *mode;
- static siphash_key_t hash_key;
- u32 hash;
memset(blk_key, 0, sizeof(*blk_key));
@@ -216,91 +349,100 @@
return -EINVAL;
}
- if (dun_bytes <= 0 || dun_bytes > BLK_CRYPTO_MAX_IV_SIZE)
+ if (dun_bytes == 0 || dun_bytes > mode->ivsize)
return -EINVAL;
if (!is_power_of_2(data_unit_size))
return -EINVAL;
- blk_key->crypto_mode = crypto_mode;
- blk_key->data_unit_size = data_unit_size;
+ blk_key->crypto_cfg.crypto_mode = crypto_mode;
+ blk_key->crypto_cfg.dun_bytes = dun_bytes;
+ blk_key->crypto_cfg.data_unit_size = data_unit_size;
+ blk_key->crypto_cfg.is_hw_wrapped = is_hw_wrapped;
blk_key->data_unit_size_bits = ilog2(data_unit_size);
blk_key->size = raw_key_size;
- blk_key->is_hw_wrapped = is_hw_wrapped;
memcpy(blk_key->raw, raw_key, raw_key_size);
-
- /*
- * The keyslot manager uses the SipHash of the key to implement O(1) key
- * lookups while avoiding leaking information about the keys. It's
- * precomputed here so that it only needs to be computed once per key.
- */
- get_random_once(&hash_key, sizeof(hash_key));
- hash = (u32)siphash(raw_key, raw_key_size, &hash_key);
- blk_crypto_key_set_hash_and_dun_bytes(blk_key, hash, dun_bytes);
return 0;
}
EXPORT_SYMBOL_GPL(blk_crypto_init_key);
+/*
+ * Check if bios with @cfg can be en/decrypted by blk-crypto (i.e. either the
+ * request queue it's submitted to supports inline crypto, or the
+ * blk-crypto-fallback is enabled and supports the cfg).
+ */
+bool blk_crypto_config_supported(struct request_queue *q,
+ const struct blk_crypto_config *cfg)
+{
+ if (IS_ENABLED(CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK) &&
+ !cfg->is_hw_wrapped)
+ return true;
+ return blk_ksm_crypto_cfg_supported(q->ksm, cfg);
+}
+
/**
- * blk_crypto_start_using_mode() - Start using blk-crypto on a device
- * @crypto_mode: the crypto mode that will be used
- * @dun_bytes: number of bytes that will be used to specify the DUN
- * @data_unit_size: the data unit size that will be used
- * @is_hw_wrapped_key: whether the key will be hardware-wrapped
+ * blk_crypto_start_using_key() - Start using a blk_crypto_key on a device
+ * @key: A key to use on the device
* @q: the request queue for the device
*
* Upper layers must call this function to ensure that either the hardware
- * supports the needed crypto settings, or the crypto API fallback has
- * transforms for the needed mode allocated and ready to go.
+ * supports the key's crypto settings, or the crypto API fallback has transforms
+ * for the needed mode allocated and ready to go. This function may allocate
+ * an skcipher, and *should not* be called from the data path, since that might
+ * cause a deadlock
*
- * Return: 0 on success; -ENOPKG if the hardware doesn't support the crypto
- * settings and blk-crypto-fallback is either disabled or the needed
- * algorithm is disabled in the crypto API; or another -errno code.
+ * Return: 0 on success; -ENOPKG if the hardware doesn't support the key and
+ * blk-crypto-fallback is either disabled or the needed algorithm
+ * is disabled in the crypto API; or another -errno code.
*/
-int blk_crypto_start_using_mode(enum blk_crypto_mode_num crypto_mode,
- unsigned int dun_bytes,
- unsigned int data_unit_size,
- bool is_hw_wrapped_key,
- struct request_queue *q)
+int blk_crypto_start_using_key(const struct blk_crypto_key *key,
+ struct request_queue *q)
{
- if (keyslot_manager_crypto_mode_supported(q->ksm, crypto_mode,
- dun_bytes, data_unit_size,
- is_hw_wrapped_key))
+ if (blk_ksm_crypto_cfg_supported(q->ksm, &key->crypto_cfg))
return 0;
- if (is_hw_wrapped_key) {
+ if (key->crypto_cfg.is_hw_wrapped) {
pr_warn_once("hardware doesn't support wrapped keys\n");
return -EOPNOTSUPP;
}
- return blk_crypto_fallback_start_using_mode(crypto_mode);
+ return blk_crypto_fallback_start_using_mode(key->crypto_cfg.crypto_mode);
}
-EXPORT_SYMBOL_GPL(blk_crypto_start_using_mode);
+EXPORT_SYMBOL_GPL(blk_crypto_start_using_key);
/**
- * blk_crypto_evict_key() - Evict a key from any inline encryption hardware
- * it may have been programmed into
- * @q: The request queue who's keyslot manager this key might have been
- * programmed into
- * @key: The key to evict
+ * blk_crypto_evict_key() - Evict a blk_crypto_key from a request_queue
+ * @q: a request_queue on which I/O using the key may have been done
+ * @key: the key to evict
*
- * Upper layers (filesystems) should call this function to ensure that a key
- * is evicted from hardware that it might have been programmed into. This
- * will call keyslot_manager_evict_key on the queue's keyslot manager, if one
- * exists, and supports the crypto algorithm with the specified data unit size.
- * Otherwise, it will evict the key from the blk-crypto-fallback's ksm.
+ * For a given request_queue, this function removes the given blk_crypto_key
+ * from the keyslot management structures and evicts it from any underlying
+ * hardware keyslot(s) or blk-crypto-fallback keyslot it may have been
+ * programmed into.
*
- * Return: 0 on success, -err on error.
+ * Upper layers must call this before freeing the blk_crypto_key. It must be
+ * called for every request_queue the key may have been used on. The key must
+ * no longer be in use by any I/O when this function is called.
+ *
+ * Context: May sleep.
*/
-int blk_crypto_evict_key(struct request_queue *q,
- const struct blk_crypto_key *key)
+void blk_crypto_evict_key(struct request_queue *q,
+ const struct blk_crypto_key *key)
{
- if (q->ksm &&
- keyslot_manager_crypto_mode_supported(q->ksm, key->crypto_mode,
- blk_crypto_key_dun_bytes(key),
- key->data_unit_size,
- key->is_hw_wrapped))
- return keyslot_manager_evict_key(q->ksm, key);
+ int err;
- return blk_crypto_fallback_evict_key(key);
+ if (blk_ksm_crypto_cfg_supported(q->ksm, &key->crypto_cfg))
+ err = blk_ksm_evict_key(q->ksm, key);
+ else
+ err = blk_crypto_fallback_evict_key(key);
+ /*
+ * An error can only occur here if the key failed to be evicted from a
+ * keyslot (due to a hardware or driver issue) or is allegedly still in
+ * use by I/O (due to a kernel bug). Even in these cases, the key is
+ * still unlinked from the keyslot management structures, and the caller
+ * is allowed and expected to free it right away. There's nothing
+ * callers can do to handle errors, so just log them and return void.
+ */
+ if (err)
+ pr_warn_ratelimited("error %d evicting key\n", err);
}
EXPORT_SYMBOL_GPL(blk_crypto_evict_key);
--
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