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-rw-r--r--crypto/adiantum.c664
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diff --git a/crypto/adiantum.c b/crypto/adiantum.c
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+++ b/crypto/adiantum.c
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+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Adiantum length-preserving encryption mode
+ *
+ * Copyright 2018 Google LLC
+ */
+
+/*
+ * Adiantum is a tweakable, length-preserving encryption mode designed for fast
+ * and secure disk encryption, especially on CPUs without dedicated crypto
+ * instructions. Adiantum encrypts each sector using the XChaCha12 stream
+ * cipher, two passes of an ε-almost-∆-universal (ε-∆U) hash function based on
+ * NH and Poly1305, and an invocation of the AES-256 block cipher on a single
+ * 16-byte block. See the paper for details:
+ *
+ * Adiantum: length-preserving encryption for entry-level processors
+ * (https://eprint.iacr.org/2018/720.pdf)
+ *
+ * For flexibility, this implementation also allows other ciphers:
+ *
+ * - Stream cipher: XChaCha12 or XChaCha20
+ * - Block cipher: any with a 128-bit block size and 256-bit key
+ *
+ * This implementation doesn't currently allow other ε-∆U hash functions, i.e.
+ * HPolyC is not supported. This is because Adiantum is ~20% faster than HPolyC
+ * but still provably as secure, and also the ε-∆U hash function of HBSH is
+ * formally defined to take two inputs (tweak, message) which makes it difficult
+ * to wrap with the crypto_shash API. Rather, some details need to be handled
+ * here. Nevertheless, if needed in the future, support for other ε-∆U hash
+ * functions could be added here.
+ */
+
+#include <crypto/b128ops.h>
+#include <crypto/chacha.h>
+#include <crypto/internal/hash.h>
+#include <crypto/internal/skcipher.h>
+#include <crypto/nhpoly1305.h>
+#include <crypto/scatterwalk.h>
+#include <linux/module.h>
+
+#include "internal.h"
+
+/*
+ * Size of right-hand part of input data, in bytes; also the size of the block
+ * cipher's block size and the hash function's output.
+ */
+#define BLOCKCIPHER_BLOCK_SIZE 16
+
+/* Size of the block cipher key (K_E) in bytes */
+#define BLOCKCIPHER_KEY_SIZE 32
+
+/* Size of the hash key (K_H) in bytes */
+#define HASH_KEY_SIZE (POLY1305_BLOCK_SIZE + NHPOLY1305_KEY_SIZE)
+
+/*
+ * The specification allows variable-length tweaks, but Linux's crypto API
+ * currently only allows algorithms to support a single length. The "natural"
+ * tweak length for Adiantum is 16, since that fits into one Poly1305 block for
+ * the best performance. But longer tweaks are useful for fscrypt, to avoid
+ * needing to derive per-file keys. So instead we use two blocks, or 32 bytes.
+ */
+#define TWEAK_SIZE 32
+
+struct adiantum_instance_ctx {
+ struct crypto_skcipher_spawn streamcipher_spawn;
+ struct crypto_spawn blockcipher_spawn;
+ struct crypto_shash_spawn hash_spawn;
+};
+
+struct adiantum_tfm_ctx {
+ struct crypto_skcipher *streamcipher;
+ struct crypto_cipher *blockcipher;
+ struct crypto_shash *hash;
+ struct poly1305_key header_hash_key;
+};
+
+struct adiantum_request_ctx {
+
+ /*
+ * Buffer for right-hand part of data, i.e.
+ *
+ * P_L => P_M => C_M => C_R when encrypting, or
+ * C_R => C_M => P_M => P_L when decrypting.
+ *
+ * Also used to build the IV for the stream cipher.
+ */
+ union {
+ u8 bytes[XCHACHA_IV_SIZE];
+ __le32 words[XCHACHA_IV_SIZE / sizeof(__le32)];
+ le128 bignum; /* interpret as element of Z/(2^{128}Z) */
+ } rbuf;
+
+ bool enc; /* true if encrypting, false if decrypting */
+
+ /*
+ * The result of the Poly1305 ε-∆U hash function applied to
+ * (bulk length, tweak)
+ */
+ le128 header_hash;
+
+ /* Sub-requests, must be last */
+ union {
+ struct shash_desc hash_desc;
+ struct skcipher_request streamcipher_req;
+ } u;
+};
+
+/*
+ * Given the XChaCha stream key K_S, derive the block cipher key K_E and the
+ * hash key K_H as follows:
+ *
+ * K_E || K_H || ... = XChaCha(key=K_S, nonce=1||0^191)
+ *
+ * Note that this denotes using bits from the XChaCha keystream, which here we
+ * get indirectly by encrypting a buffer containing all 0's.
+ */
+static int adiantum_setkey(struct crypto_skcipher *tfm, const u8 *key,
+ unsigned int keylen)
+{
+ struct adiantum_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
+ struct {
+ u8 iv[XCHACHA_IV_SIZE];
+ u8 derived_keys[BLOCKCIPHER_KEY_SIZE + HASH_KEY_SIZE];
+ struct scatterlist sg;
+ struct crypto_wait wait;
+ struct skcipher_request req; /* must be last */
+ } *data;
+ u8 *keyp;
+ int err;
+
+ /* Set the stream cipher key (K_S) */
+ crypto_skcipher_clear_flags(tctx->streamcipher, CRYPTO_TFM_REQ_MASK);
+ crypto_skcipher_set_flags(tctx->streamcipher,
+ crypto_skcipher_get_flags(tfm) &
+ CRYPTO_TFM_REQ_MASK);
+ err = crypto_skcipher_setkey(tctx->streamcipher, key, keylen);
+ crypto_skcipher_set_flags(tfm,
+ crypto_skcipher_get_flags(tctx->streamcipher) &
+ CRYPTO_TFM_RES_MASK);
+ if (err)
+ return err;
+
+ /* Derive the subkeys */
+ data = kzalloc(sizeof(*data) +
+ crypto_skcipher_reqsize(tctx->streamcipher), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+ data->iv[0] = 1;
+ sg_init_one(&data->sg, data->derived_keys, sizeof(data->derived_keys));
+ crypto_init_wait(&data->wait);
+ skcipher_request_set_tfm(&data->req, tctx->streamcipher);
+ skcipher_request_set_callback(&data->req, CRYPTO_TFM_REQ_MAY_SLEEP |
+ CRYPTO_TFM_REQ_MAY_BACKLOG,
+ crypto_req_done, &data->wait);
+ skcipher_request_set_crypt(&data->req, &data->sg, &data->sg,
+ sizeof(data->derived_keys), data->iv);
+ err = crypto_wait_req(crypto_skcipher_encrypt(&data->req), &data->wait);
+ if (err)
+ goto out;
+ keyp = data->derived_keys;
+
+ /* Set the block cipher key (K_E) */
+ crypto_cipher_clear_flags(tctx->blockcipher, CRYPTO_TFM_REQ_MASK);
+ crypto_cipher_set_flags(tctx->blockcipher,
+ crypto_skcipher_get_flags(tfm) &
+ CRYPTO_TFM_REQ_MASK);
+ err = crypto_cipher_setkey(tctx->blockcipher, keyp,
+ BLOCKCIPHER_KEY_SIZE);
+ crypto_skcipher_set_flags(tfm,
+ crypto_cipher_get_flags(tctx->blockcipher) &
+ CRYPTO_TFM_RES_MASK);
+ if (err)
+ goto out;
+ keyp += BLOCKCIPHER_KEY_SIZE;
+
+ /* Set the hash key (K_H) */
+ poly1305_core_setkey(&tctx->header_hash_key, keyp);
+ keyp += POLY1305_BLOCK_SIZE;
+
+ crypto_shash_clear_flags(tctx->hash, CRYPTO_TFM_REQ_MASK);
+ crypto_shash_set_flags(tctx->hash, crypto_skcipher_get_flags(tfm) &
+ CRYPTO_TFM_REQ_MASK);
+ err = crypto_shash_setkey(tctx->hash, keyp, NHPOLY1305_KEY_SIZE);
+ crypto_skcipher_set_flags(tfm, crypto_shash_get_flags(tctx->hash) &
+ CRYPTO_TFM_RES_MASK);
+ keyp += NHPOLY1305_KEY_SIZE;
+ WARN_ON(keyp != &data->derived_keys[ARRAY_SIZE(data->derived_keys)]);
+out:
+ kzfree(data);
+ return err;
+}
+
+/* Addition in Z/(2^{128}Z) */
+static inline void le128_add(le128 *r, const le128 *v1, const le128 *v2)
+{
+ u64 x = le64_to_cpu(v1->b);
+ u64 y = le64_to_cpu(v2->b);
+
+ r->b = cpu_to_le64(x + y);
+ r->a = cpu_to_le64(le64_to_cpu(v1->a) + le64_to_cpu(v2->a) +
+ (x + y < x));
+}
+
+/* Subtraction in Z/(2^{128}Z) */
+static inline void le128_sub(le128 *r, const le128 *v1, const le128 *v2)
+{
+ u64 x = le64_to_cpu(v1->b);
+ u64 y = le64_to_cpu(v2->b);
+
+ r->b = cpu_to_le64(x - y);
+ r->a = cpu_to_le64(le64_to_cpu(v1->a) - le64_to_cpu(v2->a) -
+ (x - y > x));
+}
+
+/*
+ * Apply the Poly1305 ε-∆U hash function to (bulk length, tweak) and save the
+ * result to rctx->header_hash. This is the calculation
+ *
+ * H_T ← Poly1305_{K_T}(bin_{128}(|L|) || T)
+ *
+ * from the procedure in section 6.4 of the Adiantum paper. The resulting value
+ * is reused in both the first and second hash steps. Specifically, it's added
+ * to the result of an independently keyed ε-∆U hash function (for equal length
+ * inputs only) taken over the left-hand part (the "bulk") of the message, to
+ * give the overall Adiantum hash of the (tweak, left-hand part) pair.
+ */
+static void adiantum_hash_header(struct skcipher_request *req)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ const struct adiantum_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
+ struct adiantum_request_ctx *rctx = skcipher_request_ctx(req);
+ const unsigned int bulk_len = req->cryptlen - BLOCKCIPHER_BLOCK_SIZE;
+ struct {
+ __le64 message_bits;
+ __le64 padding;
+ } header = {
+ .message_bits = cpu_to_le64((u64)bulk_len * 8)
+ };
+ struct poly1305_state state;
+
+ poly1305_core_init(&state);
+
+ BUILD_BUG_ON(sizeof(header) % POLY1305_BLOCK_SIZE != 0);
+ poly1305_core_blocks(&state, &tctx->header_hash_key,
+ &header, sizeof(header) / POLY1305_BLOCK_SIZE);
+
+ BUILD_BUG_ON(TWEAK_SIZE % POLY1305_BLOCK_SIZE != 0);
+ poly1305_core_blocks(&state, &tctx->header_hash_key, req->iv,
+ TWEAK_SIZE / POLY1305_BLOCK_SIZE);
+
+ poly1305_core_emit(&state, &rctx->header_hash);
+}
+
+/* Hash the left-hand part (the "bulk") of the message using NHPoly1305 */
+static int adiantum_hash_message(struct skcipher_request *req,
+ struct scatterlist *sgl, le128 *digest)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ const struct adiantum_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
+ struct adiantum_request_ctx *rctx = skcipher_request_ctx(req);
+ const unsigned int bulk_len = req->cryptlen - BLOCKCIPHER_BLOCK_SIZE;
+ struct shash_desc *hash_desc = &rctx->u.hash_desc;
+ struct sg_mapping_iter miter;
+ unsigned int i, n;
+ int err;
+
+ hash_desc->tfm = tctx->hash;
+ hash_desc->flags = 0;
+
+ err = crypto_shash_init(hash_desc);
+ if (err)
+ return err;
+
+ sg_miter_start(&miter, sgl, sg_nents(sgl),
+ SG_MITER_FROM_SG | SG_MITER_ATOMIC);
+ for (i = 0; i < bulk_len; i += n) {
+ sg_miter_next(&miter);
+ n = min_t(unsigned int, miter.length, bulk_len - i);
+ err = crypto_shash_update(hash_desc, miter.addr, n);
+ if (err)
+ break;
+ }
+ sg_miter_stop(&miter);
+ if (err)
+ return err;
+
+ return crypto_shash_final(hash_desc, (u8 *)digest);
+}
+
+/* Continue Adiantum encryption/decryption after the stream cipher step */
+static int adiantum_finish(struct skcipher_request *req)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ const struct adiantum_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
+ struct adiantum_request_ctx *rctx = skcipher_request_ctx(req);
+ const unsigned int bulk_len = req->cryptlen - BLOCKCIPHER_BLOCK_SIZE;
+ le128 digest;
+ int err;
+
+ /* If decrypting, decrypt C_M with the block cipher to get P_M */
+ if (!rctx->enc)
+ crypto_cipher_decrypt_one(tctx->blockcipher, rctx->rbuf.bytes,
+ rctx->rbuf.bytes);
+
+ /*
+ * Second hash step
+ * enc: C_R = C_M - H_{K_H}(T, C_L)
+ * dec: P_R = P_M - H_{K_H}(T, P_L)
+ */
+ err = adiantum_hash_message(req, req->dst, &digest);
+ if (err)
+ return err;
+ le128_add(&digest, &digest, &rctx->header_hash);
+ le128_sub(&rctx->rbuf.bignum, &rctx->rbuf.bignum, &digest);
+ scatterwalk_map_and_copy(&rctx->rbuf.bignum, req->dst,
+ bulk_len, BLOCKCIPHER_BLOCK_SIZE, 1);
+ return 0;
+}
+
+static void adiantum_streamcipher_done(struct crypto_async_request *areq,
+ int err)
+{
+ struct skcipher_request *req = areq->data;
+
+ if (!err)
+ err = adiantum_finish(req);
+
+ skcipher_request_complete(req, err);
+}
+
+static int adiantum_crypt(struct skcipher_request *req, bool enc)
+{
+ struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+ const struct adiantum_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
+ struct adiantum_request_ctx *rctx = skcipher_request_ctx(req);
+ const unsigned int bulk_len = req->cryptlen - BLOCKCIPHER_BLOCK_SIZE;
+ unsigned int stream_len;
+ le128 digest;
+ int err;
+
+ if (req->cryptlen < BLOCKCIPHER_BLOCK_SIZE)
+ return -EINVAL;
+
+ rctx->enc = enc;
+
+ /*
+ * First hash step
+ * enc: P_M = P_R + H_{K_H}(T, P_L)
+ * dec: C_M = C_R + H_{K_H}(T, C_L)
+ */
+ adiantum_hash_header(req);
+ err = adiantum_hash_message(req, req->src, &digest);
+ if (err)
+ return err;
+ le128_add(&digest, &digest, &rctx->header_hash);
+ scatterwalk_map_and_copy(&rctx->rbuf.bignum, req->src,
+ bulk_len, BLOCKCIPHER_BLOCK_SIZE, 0);
+ le128_add(&rctx->rbuf.bignum, &rctx->rbuf.bignum, &digest);
+
+ /* If encrypting, encrypt P_M with the block cipher to get C_M */
+ if (enc)
+ crypto_cipher_encrypt_one(tctx->blockcipher, rctx->rbuf.bytes,
+ rctx->rbuf.bytes);
+
+ /* Initialize the rest of the XChaCha IV (first part is C_M) */
+ BUILD_BUG_ON(BLOCKCIPHER_BLOCK_SIZE != 16);
+ BUILD_BUG_ON(XCHACHA_IV_SIZE != 32); /* nonce || stream position */
+ rctx->rbuf.words[4] = cpu_to_le32(1);
+ rctx->rbuf.words[5] = 0;
+ rctx->rbuf.words[6] = 0;
+ rctx->rbuf.words[7] = 0;
+
+ /*
+ * XChaCha needs to be done on all the data except the last 16 bytes;
+ * for disk encryption that usually means 4080 or 496 bytes. But ChaCha
+ * implementations tend to be most efficient when passed a whole number
+ * of 64-byte ChaCha blocks, or sometimes even a multiple of 256 bytes.
+ * And here it doesn't matter whether the last 16 bytes are written to,
+ * as the second hash step will overwrite them. Thus, round the XChaCha
+ * length up to the next 64-byte boundary if possible.
+ */
+ stream_len = bulk_len;
+ if (round_up(stream_len, CHACHA_BLOCK_SIZE) <= req->cryptlen)
+ stream_len = round_up(stream_len, CHACHA_BLOCK_SIZE);
+
+ skcipher_request_set_tfm(&rctx->u.streamcipher_req, tctx->streamcipher);
+ skcipher_request_set_crypt(&rctx->u.streamcipher_req, req->src,
+ req->dst, stream_len, &rctx->rbuf);
+ skcipher_request_set_callback(&rctx->u.streamcipher_req,
+ req->base.flags,
+ adiantum_streamcipher_done, req);
+ return crypto_skcipher_encrypt(&rctx->u.streamcipher_req) ?:
+ adiantum_finish(req);
+}
+
+static int adiantum_encrypt(struct skcipher_request *req)
+{
+ return adiantum_crypt(req, true);
+}
+
+static int adiantum_decrypt(struct skcipher_request *req)
+{
+ return adiantum_crypt(req, false);
+}
+
+static int adiantum_init_tfm(struct crypto_skcipher *tfm)
+{
+ struct skcipher_instance *inst = skcipher_alg_instance(tfm);
+ struct adiantum_instance_ctx *ictx = skcipher_instance_ctx(inst);
+ struct adiantum_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
+ struct crypto_skcipher *streamcipher;
+ struct crypto_cipher *blockcipher;
+ struct crypto_shash *hash;
+ unsigned int subreq_size;
+ int err;
+
+ streamcipher = crypto_spawn_skcipher(&ictx->streamcipher_spawn);
+ if (IS_ERR(streamcipher))
+ return PTR_ERR(streamcipher);
+
+ blockcipher = crypto_spawn_cipher(&ictx->blockcipher_spawn);
+ if (IS_ERR(blockcipher)) {
+ err = PTR_ERR(blockcipher);
+ goto err_free_streamcipher;
+ }
+
+ hash = crypto_spawn_shash(&ictx->hash_spawn);
+ if (IS_ERR(hash)) {
+ err = PTR_ERR(hash);
+ goto err_free_blockcipher;
+ }
+
+ tctx->streamcipher = streamcipher;
+ tctx->blockcipher = blockcipher;
+ tctx->hash = hash;
+
+ BUILD_BUG_ON(offsetofend(struct adiantum_request_ctx, u) !=
+ sizeof(struct adiantum_request_ctx));
+ subreq_size = max(FIELD_SIZEOF(struct adiantum_request_ctx,
+ u.hash_desc) +
+ crypto_shash_descsize(hash),
+ FIELD_SIZEOF(struct adiantum_request_ctx,
+ u.streamcipher_req) +
+ crypto_skcipher_reqsize(streamcipher));
+
+ crypto_skcipher_set_reqsize(tfm,
+ offsetof(struct adiantum_request_ctx, u) +
+ subreq_size);
+ return 0;
+
+err_free_blockcipher:
+ crypto_free_cipher(blockcipher);
+err_free_streamcipher:
+ crypto_free_skcipher(streamcipher);
+ return err;
+}
+
+static void adiantum_exit_tfm(struct crypto_skcipher *tfm)
+{
+ struct adiantum_tfm_ctx *tctx = crypto_skcipher_ctx(tfm);
+
+ crypto_free_skcipher(tctx->streamcipher);
+ crypto_free_cipher(tctx->blockcipher);
+ crypto_free_shash(tctx->hash);
+}
+
+static void adiantum_free_instance(struct skcipher_instance *inst)
+{
+ struct adiantum_instance_ctx *ictx = skcipher_instance_ctx(inst);
+
+ crypto_drop_skcipher(&ictx->streamcipher_spawn);
+ crypto_drop_spawn(&ictx->blockcipher_spawn);
+ crypto_drop_shash(&ictx->hash_spawn);
+ kfree(inst);
+}
+
+/*
+ * Check for a supported set of inner algorithms.
+ * See the comment at the beginning of this file.
+ */
+static bool adiantum_supported_algorithms(struct skcipher_alg *streamcipher_alg,
+ struct crypto_alg *blockcipher_alg,
+ struct shash_alg *hash_alg)
+{
+ if (strcmp(streamcipher_alg->base.cra_name, "xchacha12") != 0 &&
+ strcmp(streamcipher_alg->base.cra_name, "xchacha20") != 0)
+ return false;
+
+ if (blockcipher_alg->cra_cipher.cia_min_keysize > BLOCKCIPHER_KEY_SIZE ||
+ blockcipher_alg->cra_cipher.cia_max_keysize < BLOCKCIPHER_KEY_SIZE)
+ return false;
+ if (blockcipher_alg->cra_blocksize != BLOCKCIPHER_BLOCK_SIZE)
+ return false;
+
+ if (strcmp(hash_alg->base.cra_name, "nhpoly1305") != 0)
+ return false;
+
+ return true;
+}
+
+static int adiantum_create(struct crypto_template *tmpl, struct rtattr **tb)
+{
+ struct crypto_attr_type *algt;
+ const char *streamcipher_name;
+ const char *blockcipher_name;
+ const char *nhpoly1305_name;
+ struct skcipher_instance *inst;
+ struct adiantum_instance_ctx *ictx;
+ struct skcipher_alg *streamcipher_alg;
+ struct crypto_alg *blockcipher_alg;
+ struct crypto_alg *_hash_alg;
+ struct shash_alg *hash_alg;
+ int err;
+
+ algt = crypto_get_attr_type(tb);
+ if (IS_ERR(algt))
+ return PTR_ERR(algt);
+
+ if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask)
+ return -EINVAL;
+
+ streamcipher_name = crypto_attr_alg_name(tb[1]);
+ if (IS_ERR(streamcipher_name))
+ return PTR_ERR(streamcipher_name);
+
+ blockcipher_name = crypto_attr_alg_name(tb[2]);
+ if (IS_ERR(blockcipher_name))
+ return PTR_ERR(blockcipher_name);
+
+ nhpoly1305_name = crypto_attr_alg_name(tb[3]);
+ if (nhpoly1305_name == ERR_PTR(-ENOENT))
+ nhpoly1305_name = "nhpoly1305";
+ if (IS_ERR(nhpoly1305_name))
+ return PTR_ERR(nhpoly1305_name);
+
+ inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
+ if (!inst)
+ return -ENOMEM;
+ ictx = skcipher_instance_ctx(inst);
+
+ /* Stream cipher, e.g. "xchacha12" */
+ err = crypto_grab_skcipher(&ictx->streamcipher_spawn, streamcipher_name,
+ 0, crypto_requires_sync(algt->type,
+ algt->mask));
+ if (err)
+ goto out_free_inst;
+ streamcipher_alg = crypto_spawn_skcipher_alg(&ictx->streamcipher_spawn);
+
+ /* Block cipher, e.g. "aes" */
+ err = crypto_grab_spawn(&ictx->blockcipher_spawn, blockcipher_name,
+ CRYPTO_ALG_TYPE_CIPHER, CRYPTO_ALG_TYPE_MASK);
+ if (err)
+ goto out_drop_streamcipher;
+ blockcipher_alg = ictx->blockcipher_spawn.alg;
+
+ /* NHPoly1305 ε-∆U hash function */
+ _hash_alg = crypto_alg_mod_lookup(nhpoly1305_name,
+ CRYPTO_ALG_TYPE_SHASH,
+ CRYPTO_ALG_TYPE_MASK);
+ if (IS_ERR(_hash_alg)) {
+ err = PTR_ERR(_hash_alg);
+ goto out_drop_blockcipher;
+ }
+ hash_alg = __crypto_shash_alg(_hash_alg);
+ err = crypto_init_shash_spawn(&ictx->hash_spawn, hash_alg,
+ skcipher_crypto_instance(inst));
+ if (err)
+ goto out_put_hash;
+
+ /* Check the set of algorithms */
+ if (!adiantum_supported_algorithms(streamcipher_alg, blockcipher_alg,
+ hash_alg)) {
+ pr_warn("Unsupported Adiantum instantiation: (%s,%s,%s)\n",
+ streamcipher_alg->base.cra_name,
+ blockcipher_alg->cra_name, hash_alg->base.cra_name);
+ err = -EINVAL;
+ goto out_drop_hash;
+ }
+
+ /* Instance fields */
+
+ err = -ENAMETOOLONG;
+ if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
+ "adiantum(%s,%s)", streamcipher_alg->base.cra_name,
+ blockcipher_alg->cra_name) >= CRYPTO_MAX_ALG_NAME)
+ goto out_drop_hash;
+ if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
+ "adiantum(%s,%s,%s)",
+ streamcipher_alg->base.cra_driver_name,
+ blockcipher_alg->cra_driver_name,
+ hash_alg->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
+ goto out_drop_hash;
+
+ inst->alg.base.cra_flags = streamcipher_alg->base.cra_flags &
+ CRYPTO_ALG_ASYNC;
+ inst->alg.base.cra_blocksize = BLOCKCIPHER_BLOCK_SIZE;
+ inst->alg.base.cra_ctxsize = sizeof(struct adiantum_tfm_ctx);
+ inst->alg.base.cra_alignmask = streamcipher_alg->base.cra_alignmask |
+ hash_alg->base.cra_alignmask;
+ /*
+ * The block cipher is only invoked once per message, so for long
+ * messages (e.g. sectors for disk encryption) its performance doesn't
+ * matter as much as that of the stream cipher and hash function. Thus,
+ * weigh the block cipher's ->cra_priority less.
+ */
+ inst->alg.base.cra_priority = (4 * streamcipher_alg->base.cra_priority +
+ 2 * hash_alg->base.cra_priority +
+ blockcipher_alg->cra_priority) / 7;
+
+ inst->alg.setkey = adiantum_setkey;
+ inst->alg.encrypt = adiantum_encrypt;
+ inst->alg.decrypt = adiantum_decrypt;
+ inst->alg.init = adiantum_init_tfm;
+ inst->alg.exit = adiantum_exit_tfm;
+ inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(streamcipher_alg);
+ inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(streamcipher_alg);
+ inst->alg.ivsize = TWEAK_SIZE;
+
+ inst->free = adiantum_free_instance;
+
+ err = skcipher_register_instance(tmpl, inst);
+ if (err)
+ goto out_drop_hash;
+
+ crypto_mod_put(_hash_alg);
+ return 0;
+
+out_drop_hash:
+ crypto_drop_shash(&ictx->hash_spawn);
+out_put_hash:
+ crypto_mod_put(_hash_alg);
+out_drop_blockcipher:
+ crypto_drop_spawn(&ictx->blockcipher_spawn);
+out_drop_streamcipher:
+ crypto_drop_skcipher(&ictx->streamcipher_spawn);
+out_free_inst:
+ kfree(inst);
+ return err;
+}
+
+/* adiantum(streamcipher_name, blockcipher_name [, nhpoly1305_name]) */
+static struct crypto_template adiantum_tmpl = {
+ .name = "adiantum",
+ .create = adiantum_create,
+ .module = THIS_MODULE,
+};
+
+static int __init adiantum_module_init(void)
+{
+ return crypto_register_template(&adiantum_tmpl);
+}
+
+static void __exit adiantum_module_exit(void)
+{
+ crypto_unregister_template(&adiantum_tmpl);
+}
+
+module_init(adiantum_module_init);
+module_exit(adiantum_module_exit);
+
+MODULE_DESCRIPTION("Adiantum length-preserving encryption mode");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Eric Biggers <ebiggers@google.com>");
+MODULE_ALIAS_CRYPTO("adiantum");
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-06 17:32:16 +0300