--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2019 Google LLC
+ */
+
+/*
+ * Refer to Documentation/block/inline-encryption.rst for detailed explanation.
+ */
+
+#define pr_fmt(fmt) "blk-crypto-fallback: " fmt
+
+#include <crypto/skcipher.h>
+#include <linux/blk-cgroup.h>
+#include <linux/blk-crypto.h>
+#include <linux/blkdev.h>
+#include <linux/crypto.h>
+#include <linux/keyslot-manager.h>
+#include <linux/mempool.h>
+#include <linux/module.h>
+#include <linux/random.h>
+
+#include "blk-crypto-internal.h"
+
+static unsigned int num_prealloc_bounce_pg = 32;
+module_param(num_prealloc_bounce_pg, uint, 0);
+MODULE_PARM_DESC(num_prealloc_bounce_pg,
+ "Number of preallocated bounce pages for the blk-crypto crypto API fallback");
+
+static unsigned int blk_crypto_num_keyslots = 100;
+module_param_named(num_keyslots, blk_crypto_num_keyslots, uint, 0);
+MODULE_PARM_DESC(num_keyslots,
+ "Number of keyslots for the blk-crypto crypto API fallback");
+
+static unsigned int num_prealloc_fallback_crypt_ctxs = 128;
+module_param(num_prealloc_fallback_crypt_ctxs, uint, 0);
+MODULE_PARM_DESC(num_prealloc_crypt_fallback_ctxs,
+ "Number of preallocated bio fallback crypto contexts for blk-crypto to use during crypto API fallback");
+
+struct bio_fallback_crypt_ctx {
+ struct bio_crypt_ctx crypt_ctx;
+ /*
+ * 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;
+ union {
+ struct {
+ struct work_struct work;
+ struct bio *bio;
+ };
+ struct {
+ void *bi_private_orig;
+ bio_end_io_t *bi_end_io_orig;
+ };
+ };
+};
+
+static struct kmem_cache *bio_fallback_crypt_ctx_cache;
+static mempool_t *bio_fallback_crypt_ctx_pool;
+
+/*
+ * Allocating a crypto tfm during I/O can deadlock, so we have to preallocate
+ * all of a mode's tfms when that mode starts being used. Since each mode may
+ * need all the keyslots at some point, each mode needs its own tfm for each
+ * keyslot; thus, a keyslot may contain tfms for multiple modes. However, to
+ * match the behavior of real inline encryption hardware (which only supports a
+ * single encryption context per keyslot), we only allow one tfm per keyslot to
+ * be used at a time - the rest of the unused tfms have their keys cleared.
+ */
+static DEFINE_MUTEX(tfms_init_lock);
+static bool tfms_inited[BLK_ENCRYPTION_MODE_MAX];
+
+static struct blk_crypto_keyslot {
+ enum blk_crypto_mode_num crypto_mode;
+ struct crypto_skcipher *tfms[BLK_ENCRYPTION_MODE_MAX];
+} *blk_crypto_keyslots;
+
+static struct blk_keyslot_manager blk_crypto_ksm;
+static struct workqueue_struct *blk_crypto_wq;
+static mempool_t *blk_crypto_bounce_page_pool;
+
+/*
+ * This is the key we set when evicting a keyslot. This *should* be the all 0's
+ * key, but AES-XTS rejects that key, so we use some random bytes instead.
+ */
+static u8 blank_key[BLK_CRYPTO_MAX_KEY_SIZE];
+
+static void blk_crypto_evict_keyslot(unsigned int slot)
+{
+ struct blk_crypto_keyslot *slotp = &blk_crypto_keyslots[slot];
+ enum blk_crypto_mode_num crypto_mode = slotp->crypto_mode;
+ int err;
+
+ WARN_ON(slotp->crypto_mode == BLK_ENCRYPTION_MODE_INVALID);
+
+ /* Clear the key in the skcipher */
+ err = crypto_skcipher_setkey(slotp->tfms[crypto_mode], blank_key,
+ blk_crypto_modes[crypto_mode].keysize);
+ WARN_ON(err);
+ slotp->crypto_mode = BLK_ENCRYPTION_MODE_INVALID;
+}
+
+static int blk_crypto_keyslot_program(struct blk_keyslot_manager *ksm,
+ const struct blk_crypto_key *key,
+ unsigned int slot)
+{
+ struct blk_crypto_keyslot *slotp = &blk_crypto_keyslots[slot];
+ const enum blk_crypto_mode_num crypto_mode =
+ key->crypto_cfg.crypto_mode;
+ int err;
+
+ if (crypto_mode != slotp->crypto_mode &&
+ slotp->crypto_mode != BLK_ENCRYPTION_MODE_INVALID)
+ blk_crypto_evict_keyslot(slot);
+
+ slotp->crypto_mode = crypto_mode;
+ err = crypto_skcipher_setkey(slotp->tfms[crypto_mode], key->raw,
+ key->size);
+ if (err) {
+ blk_crypto_evict_keyslot(slot);
+ return err;
+ }
+ return 0;
+}
+
+static int blk_crypto_keyslot_evict(struct blk_keyslot_manager *ksm,
+ const struct blk_crypto_key *key,
+ unsigned int slot)
+{
+ blk_crypto_evict_keyslot(slot);
+ return 0;
+}
+
+/*
+ * The crypto API fallback KSM ops - only used for a bio when it specifies a
+ * blk_crypto_key that was not supported by the device's inline encryption
+ * hardware.
+ */
+static const struct blk_ksm_ll_ops blk_crypto_ksm_ll_ops = {
+ .keyslot_program = blk_crypto_keyslot_program,
+ .keyslot_evict = blk_crypto_keyslot_evict,
+};
+
+static void blk_crypto_fallback_encrypt_endio(struct bio *enc_bio)
+{
+ struct bio *src_bio = enc_bio->bi_private;
+ int i;
+
+ for (i = 0; i < enc_bio->bi_vcnt; i++)
+ mempool_free(enc_bio->bi_io_vec[i].bv_page,
+ blk_crypto_bounce_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;
+
+ bio_clone_blkg_association(bio, bio_src);
+ blkcg_bio_issue_init(bio);
+
+ return bio;
+}
+
+static bool blk_crypto_alloc_cipher_req(struct blk_ksm_keyslot *slot,
+ struct skcipher_request **ciph_req_ret,
+ struct crypto_wait *wait)
+{
+ struct skcipher_request *ciph_req;
+ const struct blk_crypto_keyslot *slotp;
+ int keyslot_idx = blk_ksm_get_slot_idx(slot);
+
+ slotp = &blk_crypto_keyslots[keyslot_idx];
+ ciph_req = skcipher_request_alloc(slotp->tfms[slotp->crypto_mode],
+ GFP_NOIO);
+ if (!ciph_req)
+ return false;
+
+ skcipher_request_set_callback(ciph_req,
+ CRYPTO_TFM_REQ_MAY_BACKLOG |
+ CRYPTO_TFM_REQ_MAY_SLEEP,
+ crypto_req_done, wait);
+ *ciph_req_ret = ciph_req;
+
+ return true;
+}
+
+static bool 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 false;
+ }
+ bio_chain(split_bio, bio);
+ generic_make_request(bio);
+ *bio_ptr = split_bio;
+ }
+
+ return true;
+}
+
+union blk_crypto_iv {
+ __le64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE];
+ u8 bytes[BLK_CRYPTO_MAX_IV_SIZE];
+};
+
+static void blk_crypto_dun_to_iv(const u64 dun[BLK_CRYPTO_DUN_ARRAY_SIZE],
+ union blk_crypto_iv *iv)
+{
+ int i;
+
+ for (i = 0; i < BLK_CRYPTO_DUN_ARRAY_SIZE; i++)
+ iv->dun[i] = cpu_to_le64(dun[i]);
+}
+
+/*
+ * The crypto API fallback's encryption routine.
+ * Allocate a bounce bio for encryption, encrypt the input bio using crypto API,
+ * and replace *bio_ptr with the bounce bio. May split input bio if it's too
+ * large. Returns true on success. Returns false and sets bio->bi_status on
+ * error.
+ */
+static bool blk_crypto_fallback_encrypt_bio(struct bio **bio_ptr)
+{
+ struct bio *src_bio, *enc_bio;
+ struct bio_crypt_ctx *bc;
+ struct blk_ksm_keyslot *slot;
+ int data_unit_size;
+ struct skcipher_request *ciph_req = NULL;
+ DECLARE_CRYPTO_WAIT(wait);
+ u64 curr_dun[BLK_CRYPTO_DUN_ARRAY_SIZE];
+ struct scatterlist src, dst;
+ union blk_crypto_iv iv;
+ unsigned int i, j;
+ bool ret = false;
+ blk_status_t blk_st;
+
+ /* Split the bio if it's too big for single page bvec */
+ if (!blk_crypto_split_bio_if_needed(bio_ptr))
+ return false;
+
+ src_bio = *bio_ptr;
+ bc = src_bio->bi_crypt_context;
+ data_unit_size = bc->bc_key->crypto_cfg.data_unit_size;
+
+ /* Allocate bounce bio for encryption */
+ enc_bio = blk_crypto_clone_bio(src_bio);
+ if (!enc_bio) {
+ src_bio->bi_status = BLK_STS_RESOURCE;
+ return false;
+ }
+
+ /*
+ * Use the crypto API fallback keyslot manager to get a crypto_skcipher
+ * for the algorithm and key specified for this bio.
+ */
+ blk_st = blk_ksm_get_slot_for_key(&blk_crypto_ksm, bc->bc_key, &slot);
+ if (blk_st != BLK_STS_OK) {
+ src_bio->bi_status = blk_st;
+ goto out_put_enc_bio;
+ }
+
+ /* and then allocate an skcipher_request for it */
+ if (!blk_crypto_alloc_cipher_req(slot, &ciph_req, &wait)) {
+ src_bio->bi_status = BLK_STS_RESOURCE;
+ goto out_release_keyslot;
+ }
+
+ memcpy(curr_dun, bc->bc_dun, sizeof(curr_dun));
+ sg_init_table(&src, 1);
+ sg_init_table(&dst, 1);
+
+ skcipher_request_set_crypt(ciph_req, &src, &dst, data_unit_size,
+ iv.bytes);
+
+ /* Encrypt each page in the bounce bio */
+ for (i = 0; i < enc_bio->bi_vcnt; i++) {
+ struct bio_vec *enc_bvec = &enc_bio->bi_io_vec[i];
+ struct page *plaintext_page = enc_bvec->bv_page;
+ struct page *ciphertext_page =
+ mempool_alloc(blk_crypto_bounce_page_pool, GFP_NOIO);
+
+ enc_bvec->bv_page = ciphertext_page;
+
+ if (!ciphertext_page) {
+ src_bio->bi_status = BLK_STS_RESOURCE;
+ goto out_free_bounce_pages;
+ }
+
+ sg_set_page(&src, plaintext_page, data_unit_size,
+ enc_bvec->bv_offset);
+ sg_set_page(&dst, ciphertext_page, data_unit_size,
+ enc_bvec->bv_offset);
+
+ /* Encrypt each data unit in this page */
+ for (j = 0; j < enc_bvec->bv_len; j += data_unit_size) {
+ blk_crypto_dun_to_iv(curr_dun, &iv);
+ if (crypto_wait_req(crypto_skcipher_encrypt(ciph_req),
+ &wait)) {
+ i++;
+ src_bio->bi_status = BLK_STS_IOERR;
+ goto out_free_bounce_pages;
+ }
+ bio_crypt_dun_increment(curr_dun, 1);
+ src.offset += data_unit_size;
+ dst.offset += data_unit_size;
+ }
+ }
+
+ enc_bio->bi_private = src_bio;
+ enc_bio->bi_end_io = blk_crypto_fallback_encrypt_endio;
+ *bio_ptr = enc_bio;
+ ret = true;
+
+ enc_bio = NULL;
+ goto out_free_ciph_req;
+
+out_free_bounce_pages:
+ while (i > 0)
+ mempool_free(enc_bio->bi_io_vec[--i].bv_page,
+ blk_crypto_bounce_page_pool);
+out_free_ciph_req:
+ skcipher_request_free(ciph_req);
+out_release_keyslot:
+ blk_ksm_put_slot(slot);
+out_put_enc_bio:
+ if (enc_bio)
+ bio_put(enc_bio);
+
+ return ret;
+}
+
+/*
+ * The crypto API fallback's main decryption routine.
+ * Decrypts input bio in place, and calls bio_endio on the bio.
+ */
+static void blk_crypto_fallback_decrypt_bio(struct work_struct *work)
+{
+ struct bio_fallback_crypt_ctx *f_ctx =
+ container_of(work, struct bio_fallback_crypt_ctx, work);
+ struct bio *bio = f_ctx->bio;
+ struct bio_crypt_ctx *bc = &f_ctx->crypt_ctx;
+ struct blk_ksm_keyslot *slot;
+ struct skcipher_request *ciph_req = NULL;
+ DECLARE_CRYPTO_WAIT(wait);
+ u64 curr_dun[BLK_CRYPTO_DUN_ARRAY_SIZE];
+ union blk_crypto_iv iv;
+ struct scatterlist sg;
+ struct bio_vec bv;
+ struct bvec_iter iter;
+ const int data_unit_size = bc->bc_key->crypto_cfg.data_unit_size;
+ unsigned int i;
+ blk_status_t blk_st;
+
+ /*
+ * Use the crypto API fallback keyslot manager to get a crypto_skcipher
+ * for the algorithm and key specified for this bio.
+ */
+ blk_st = blk_ksm_get_slot_for_key(&blk_crypto_ksm, bc->bc_key, &slot);
+ if (blk_st != BLK_STS_OK) {
+ bio->bi_status = blk_st;
+ goto out_no_keyslot;
+ }
+
+ /* and then allocate an skcipher_request for it */
+ if (!blk_crypto_alloc_cipher_req(slot, &ciph_req, &wait)) {
+ bio->bi_status = BLK_STS_RESOURCE;
+ goto out;
+ }
+
+ memcpy(curr_dun, bc->bc_dun, sizeof(curr_dun));
+ sg_init_table(&sg, 1);
+ skcipher_request_set_crypt(ciph_req, &sg, &sg, data_unit_size,
+ iv.bytes);
+
+ /* Decrypt each segment in the bio */
+ __bio_for_each_segment(bv, bio, iter, f_ctx->crypt_iter) {
+ struct page *page = bv.bv_page;
+
+ sg_set_page(&sg, page, data_unit_size, bv.bv_offset);
+
+ /* Decrypt each data unit in the segment */
+ for (i = 0; i < bv.bv_len; i += data_unit_size) {
+ blk_crypto_dun_to_iv(curr_dun, &iv);
+ if (crypto_wait_req(crypto_skcipher_decrypt(ciph_req),
+ &wait)) {
+ bio->bi_status = BLK_STS_IOERR;
+ goto out;
+ }
+ bio_crypt_dun_increment(curr_dun, 1);
+ sg.offset += data_unit_size;
+ }
+ }
+
+out:
+ skcipher_request_free(ciph_req);
+ blk_ksm_put_slot(slot);
+out_no_keyslot:
+ mempool_free(f_ctx, bio_fallback_crypt_ctx_pool);
+ bio_endio(bio);
+}
+
+/**
+ * blk_crypto_fallback_decrypt_endio - queue bio for fallback decryption
+ *
+ * @bio: the bio to queue
+ *
+ * Restore bi_private and bi_end_io, and queue the bio for decryption into a
+ * workqueue, since this function will be called from an atomic context.
+ */
+static void blk_crypto_fallback_decrypt_endio(struct bio *bio)
+{
+ struct bio_fallback_crypt_ctx *f_ctx = bio->bi_private;
+
+ bio->bi_private = f_ctx->bi_private_orig;
+ bio->bi_end_io = f_ctx->bi_end_io_orig;
+
+ /* If there was an IO error, don't queue for decrypt. */
+ if (bio->bi_status) {
+ mempool_free(f_ctx, bio_fallback_crypt_ctx_pool);
+ bio_endio(bio);
+ return;
+ }
+
+ INIT_WORK(&f_ctx->work, blk_crypto_fallback_decrypt_bio);
+ f_ctx->bio = bio;
+ queue_work(blk_crypto_wq, &f_ctx->work);
+}
+
+/**
+ * blk_crypto_fallback_bio_prep - Prepare a bio to use fallback en/decryption
+ *
+ * @bio_ptr: pointer to the bio to prepare
+ *
+ * If bio is doing a WRITE operation, this splits the bio into two parts if it's
+ * too big (see blk_crypto_split_bio_if_needed). It then allocates a bounce bio
+ * for the first part, encrypts it, and update bio_ptr to point to the bounce
+ * bio.
+ *
+ * For a READ operation, we mark the bio for decryption by using bi_private and
+ * bi_end_io.
+ *
+ * In either case, this function will make the bio look like a regular bio (i.e.
+ * as if no encryption context was ever specified) for the purposes of the rest
+ * of the stack except for blk-integrity (blk-integrity and blk-crypto are not
+ * currently supported together).
+ *
+ * Return: true on success. Sets bio->bi_status and returns false on error.
+ */
+bool blk_crypto_fallback_bio_prep(struct bio **bio_ptr)
+{
+ struct bio *bio = *bio_ptr;
+ struct bio_crypt_ctx *bc = bio->bi_crypt_context;
+ struct bio_fallback_crypt_ctx *f_ctx;
+
+ if (WARN_ON_ONCE(!tfms_inited[bc->bc_key->crypto_cfg.crypto_mode])) {
+ /* User didn't call blk_crypto_start_using_key() first */
+ bio->bi_status = BLK_STS_IOERR;
+ return false;
+ }
+
+ if (!blk_ksm_crypto_cfg_supported(&blk_crypto_ksm,
+ &bc->bc_key->crypto_cfg)) {
+ bio->bi_status = BLK_STS_NOTSUPP;
+ return false;
+ }
+
+ if (bio_data_dir(bio) == WRITE)
+ return blk_crypto_fallback_encrypt_bio(bio_ptr);
+
+ /*
+ * bio READ case: Set up a f_ctx in the bio's bi_private and set the
+ * bi_end_io appropriately to trigger decryption when the bio is ended.
+ */
+ f_ctx = mempool_alloc(bio_fallback_crypt_ctx_pool, GFP_NOIO);
+ f_ctx->crypt_ctx = *bc;
+ f_ctx->crypt_iter = bio->bi_iter;
+ f_ctx->bi_private_orig = bio->bi_private;
+ f_ctx->bi_end_io_orig = bio->bi_end_io;
+ bio->bi_private = (void *)f_ctx;
+ bio->bi_end_io = blk_crypto_fallback_decrypt_endio;
+ bio_crypt_free_ctx(bio);
+
+ return true;
+}
+
+int blk_crypto_fallback_evict_key(const struct blk_crypto_key *key)
+{
+ return blk_ksm_evict_key(&blk_crypto_ksm, key);
+}
+
+static bool blk_crypto_fallback_inited;
+static int blk_crypto_fallback_init(void)
+{
+ int i;
+ int err = -ENOMEM;
+
+ if (blk_crypto_fallback_inited)
+ return 0;
+
+ prandom_bytes(blank_key, BLK_CRYPTO_MAX_KEY_SIZE);
+
+ err = blk_ksm_init(&blk_crypto_ksm, blk_crypto_num_keyslots);
+ if (err)
+ goto out;
+ err = -ENOMEM;
+
+ blk_crypto_ksm.ksm_ll_ops = blk_crypto_ksm_ll_ops;
+ blk_crypto_ksm.max_dun_bytes_supported = BLK_CRYPTO_MAX_IV_SIZE;
+
+ /* All blk-crypto modes have a crypto API fallback. */
+ for (i = 0; i < BLK_ENCRYPTION_MODE_MAX; i++)
+ blk_crypto_ksm.crypto_modes_supported[i] = 0xFFFFFFFF;
+ blk_crypto_ksm.crypto_modes_supported[BLK_ENCRYPTION_MODE_INVALID] = 0;
+
+ blk_crypto_wq = alloc_workqueue("blk_crypto_wq",
+ WQ_UNBOUND | WQ_HIGHPRI |
+ WQ_MEM_RECLAIM, num_online_cpus());
+ if (!blk_crypto_wq)
+ goto fail_free_ksm;
+
+ blk_crypto_keyslots = kcalloc(blk_crypto_num_keyslots,
+ sizeof(blk_crypto_keyslots[0]),
+ GFP_KERNEL);
+ if (!blk_crypto_keyslots)
+ goto fail_free_wq;
+
+ blk_crypto_bounce_page_pool =
+ mempool_create_page_pool(num_prealloc_bounce_pg, 0);
+ if (!blk_crypto_bounce_page_pool)
+ goto fail_free_keyslots;
+
+ bio_fallback_crypt_ctx_cache = KMEM_CACHE(bio_fallback_crypt_ctx, 0);
+ if (!bio_fallback_crypt_ctx_cache)
+ goto fail_free_bounce_page_pool;
+
+ bio_fallback_crypt_ctx_pool =
+ mempool_create_slab_pool(num_prealloc_fallback_crypt_ctxs,
+ bio_fallback_crypt_ctx_cache);
+ if (!bio_fallback_crypt_ctx_pool)
+ goto fail_free_crypt_ctx_cache;
+
+ blk_crypto_fallback_inited = true;
+
+ return 0;
+fail_free_crypt_ctx_cache:
+ kmem_cache_destroy(bio_fallback_crypt_ctx_cache);
+fail_free_bounce_page_pool:
+ mempool_destroy(blk_crypto_bounce_page_pool);
+fail_free_keyslots:
+ kfree(blk_crypto_keyslots);
+fail_free_wq:
+ destroy_workqueue(blk_crypto_wq);
+fail_free_ksm:
+ blk_ksm_destroy(&blk_crypto_ksm);
+out:
+ return err;
+}
+
+/*
+ * Prepare blk-crypto-fallback for the specified crypto mode.
+ * Returns -ENOPKG if the needed crypto API support is missing.
+ */
+int blk_crypto_fallback_start_using_mode(enum blk_crypto_mode_num mode_num)
+{
+ const char *cipher_str = blk_crypto_modes[mode_num].cipher_str;
+ struct blk_crypto_keyslot *slotp;
+ unsigned int i;
+ int err = 0;
+
+ /*
+ * Fast path
+ * Ensure that updates to blk_crypto_keyslots[i].tfms[mode_num]
+ * for each i are visible before we try to access them.
+ */
+ if (likely(smp_load_acquire(&tfms_inited[mode_num])))
+ return 0;
+
+ mutex_lock(&tfms_init_lock);
+ if (tfms_inited[mode_num])
+ goto out;
+
+ err = blk_crypto_fallback_init();
+ if (err)
+ goto out;
+
+ for (i = 0; i < blk_crypto_num_keyslots; i++) {
+ slotp = &blk_crypto_keyslots[i];
+ slotp->tfms[mode_num] = crypto_alloc_skcipher(cipher_str, 0, 0);
+ if (IS_ERR(slotp->tfms[mode_num])) {
+ err = PTR_ERR(slotp->tfms[mode_num]);
+ if (err == -ENOENT) {
+ pr_warn_once("Missing crypto API support for \"%s\"\n",
+ cipher_str);
+ err = -ENOPKG;
+ }
+ slotp->tfms[mode_num] = NULL;
+ goto out_free_tfms;
+ }
+
+ crypto_skcipher_set_flags(slotp->tfms[mode_num],
+ CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
+ }
+
+ /*
+ * Ensure that updates to blk_crypto_keyslots[i].tfms[mode_num]
+ * for each i are visible before we set tfms_inited[mode_num].
+ */
+ smp_store_release(&tfms_inited[mode_num], true);
+ goto out;
+
+out_free_tfms:
+ for (i = 0; i < blk_crypto_num_keyslots; i++) {
+ slotp = &blk_crypto_keyslots[i];
+ crypto_free_skcipher(slotp->tfms[mode_num]);
+ slotp->tfms[mode_num] = NULL;
+ }
+out:
+ mutex_unlock(&tfms_init_lock);
+ return err;
+}
const struct blk_crypto_mode blk_crypto_modes[] = {
[BLK_ENCRYPTION_MODE_AES_256_XTS] = {
+ .cipher_str = "xts(aes)",
.keysize = 64,
.ivsize = 16,
},
[BLK_ENCRYPTION_MODE_AES_128_CBC_ESSIV] = {
+ .cipher_str = "essiv(cbc(aes),sha256)",
.keysize = 16,
.ivsize = 16,
},
[BLK_ENCRYPTION_MODE_ADIANTUM] = {
+ .cipher_str = "adiantum(xchacha12,aes)",
.keysize = 32,
.ivsize = 32,
},
*
* @bio_ptr: pointer to original bio pointer
*
- * Succeeds if the bio doesn't have inline encryption enabled or if the bio
- * crypt context provided for the bio is supported by the underlying device's
- * inline encryption hardware. Ends the bio with error otherwise.
+ * If the bio crypt context provided for the bio is supported by the underlying
+ * device's inline encryption hardware, do nothing.
+ *
+ * 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
+ * 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.
*
* Caller must ensure bio has bio_crypt_ctx.
*
{
struct bio *bio = *bio_ptr;
const struct blk_crypto_key *bc_key = bio->bi_crypt_context->bc_key;
- blk_status_t blk_st = BLK_STS_IOERR;
/* Error if bio has no data. */
- if (WARN_ON_ONCE(!bio_has_data(bio)))
+ if (WARN_ON_ONCE(!bio_has_data(bio))) {
+ bio->bi_status = BLK_STS_IOERR;
goto fail;
+ }
- if (!bio_crypt_check_alignment(bio))
+ if (!bio_crypt_check_alignment(bio)) {
+ bio->bi_status = BLK_STS_IOERR;
goto fail;
+ }
/*
- * Success if device supports the encryption context.
+ * Success if device supports the encryption context, or if we succeeded
+ * in falling back to the crypto API.
*/
- if (!blk_ksm_crypto_cfg_supported(bio->bi_disk->queue->ksm,
- &bc_key->crypto_cfg)) {
- blk_st = BLK_STS_NOTSUPP;
- goto fail;
- }
+ if (blk_ksm_crypto_cfg_supported(bio->bi_disk->queue->ksm,
+ &bc_key->crypto_cfg))
+ return true;
- return true;
+ if (blk_crypto_fallback_bio_prep(bio_ptr))
+ return true;
fail:
- (*bio_ptr)->bi_status = blk_st;
bio_endio(*bio_ptr);
return false;
}
return 0;
}
+/*
+ * 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)
{
- return blk_ksm_crypto_cfg_supported(q->ksm, cfg);
+ return IS_ENABLED(CONFIG_BLK_INLINE_ENCRYPTION_FALLBACK) ||
+ blk_ksm_crypto_cfg_supported(q->ksm, cfg);
}
/**
* @key: A key to use on the device
* @q: the request queue for the device
*
- * Upper layers must call this function to ensure that the hardware supports
- * the key's crypto settings.
+ * Upper layers must call this function to ensure that either the hardware
+ * 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 key
+ * 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_key(const struct blk_crypto_key *key,
struct request_queue *q)
{
if (blk_ksm_crypto_cfg_supported(q->ksm, &key->crypto_cfg))
return 0;
- return -ENOPKG;
+ return blk_crypto_fallback_start_using_mode(key->crypto_cfg.crypto_mode);
}
/**
if (blk_ksm_crypto_cfg_supported(q->ksm, &key->crypto_cfg))
return blk_ksm_evict_key(q->ksm, key);
- return 0;
+ /*
+ * If the request queue's associated inline encryption hardware didn't
+ * have support for the key, then the key might have been programmed
+ * into the fallback keyslot manager, so try to evict from there.
+ */
+ return blk_crypto_fallback_evict_key(key);
}
projects / platform / kernel / linux-rpi.git / commitdiff