On Mon, Oct 26, 2020 at 03:04:44PM +0200, Gilad Ben-Yossef wrote: > diff --git a/crypto/eboiv.c b/crypto/eboiv.c > new file mode 100644 > index 000000000000..467833e89139 > --- /dev/null > +++ b/crypto/eboiv.c > @@ -0,0 +1,295 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * EBOIV skcipher template for block encryption > + * > + * This template encapsulates the Encrypted byte-offset IV generation algorithm > + * used in Bitlocker in CBC mode by dm-crypt, which converts the initial vector > + * for the skcipher used for block encryption, by encrypting it using the same > + * skcipher key as encryption key. Usually, the input IV is a 64-bit sector > + * offset (the byte offset of the start of the sector) in LE representation > + * zero-padded to the size of the IV, but this * is not assumed by this driver. > + * > + * The typical use of this template is to instantiate the skcipher > + * 'eboiv(cbc(aes))', which is the only instantiation used by > + * dm-crypt for supporting BitLocker AES-CBC mode as specified in > + * https://www.jedec.org/sites/default/files/docs/JESD223C.pdf > + * > + * Copyright (C) 2020 ARM Limited or its affiliates. > + * Written by Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx> > + * > + * Heavily based on: > + * > + * ESSIV skcipher and aead template for block encryption > + * Copyright (c) 2019 Linaro, Ltd. <ard.biesheuvel@xxxxxxxxxx> > + * > + * and > + * > + * dm-crypt eboiv code > + * by Milan Broz <gmazyland@xxxxxxxxx> and Ard Biesheuvel <ardb@xxxxxxxxxx> > + * > + */ > + > +#include <crypto/internal/skcipher.h> > +#include <crypto/scatterwalk.h> > +#include <linux/module.h> > + > +#include "internal.h" internal.h shouldn't be included here. > + > +struct eboiv_instance_ctx { > + struct crypto_skcipher_spawn skcipher_spawn; > + char eboiv_cipher_name[CRYPTO_MAX_ALG_NAME]; > +}; The 'eboiv_cipher_name' field isn't used. > +static void eboiv_skcipher_iv_done(struct crypto_async_request *areq, int err) > +{ > + struct eboiv_req_ctx *req_ctx = areq->data; > + struct skcipher_request *req = req_ctx->req; > + int ret; > + > + if (!err) { > + > + ret = eboiv_skcipher_do_crypt(req, req_ctx->enc); > + > + if ((ret == -EINPROGRESS) || (ret == -EBUSY)) > + return; > + } > + > + skcipher_request_complete(req, err); > +} This looks wrong, because if eboiv_skcipher_do_crypt() fails, skcipher_request_complete() will be called with err=0. > +static int eboiv_create(struct crypto_template *tmpl, struct rtattr **tb) > +{ > + struct crypto_attr_type *algt; > + const char *inner_cipher_name; > + struct skcipher_instance *skcipher_inst = NULL; > + struct crypto_instance *inst; > + struct crypto_alg *base, *block_base; > + struct eboiv_instance_ctx *ictx; > + struct skcipher_alg *skcipher_alg = NULL; > + int ivsize; > + u32 mask; > + int err; > + > + algt = crypto_get_attr_type(tb); > + if (IS_ERR(algt)) > + return PTR_ERR(algt); Need to check that the algorithm is being instantiated as skcipher. crypto_check_attr_type() should be used. > + > + inner_cipher_name = crypto_attr_alg_name(tb[1]); > + if (IS_ERR(inner_cipher_name)) > + return PTR_ERR(inner_cipher_name); The result of crypto_attr_alg_name() can be passed directly to crypto_grab_skcipher(). > + mask = crypto_algt_inherited_mask(algt); > + > + skcipher_inst = kzalloc(sizeof(*skcipher_inst) + sizeof(*ictx), GFP_KERNEL); > + if (!skcipher_inst) > + return -ENOMEM; > + > + inst = skcipher_crypto_instance(skcipher_inst); > + base = &skcipher_inst->alg.base; > + ictx = crypto_instance_ctx(inst); > + > + /* Symmetric cipher, e.g., "cbc(aes)" */ > + err = crypto_grab_skcipher(&ictx->skcipher_spawn, inst, inner_cipher_name, 0, mask); > + if (err) > + goto out_free_inst; > + > + skcipher_alg = crypto_spawn_skcipher_alg(&ictx->skcipher_spawn); > + block_base = &skcipher_alg->base; > + ivsize = crypto_skcipher_alg_ivsize(skcipher_alg); > + > + if (ivsize != block_base->cra_blocksize) > + goto out_drop_skcipher; Shouldn't it be verified that the underlying algorithm is actually cbc? > + skcipher_inst->alg.chunksize = crypto_skcipher_alg_chunksize(skcipher_alg); > + skcipher_inst->alg.walksize = crypto_skcipher_alg_walksize(skcipher_alg); Setting these isn't necessary. > + > + skcipher_inst->free = eboiv_skcipher_free_instance; > + > + err = skcipher_register_instance(tmpl, skcipher_inst); > + > + if (err) > + goto out_drop_skcipher; > + > + return 0; > + > +out_drop_skcipher: > + crypto_drop_skcipher(&ictx->skcipher_spawn); > +out_free_inst: > + kfree(skcipher_inst); > + return err; > +} eboiv_skcipher_free_instance() can be called on the error path. > +/* eboiv(cipher_name) */ > +static struct crypto_template eboiv_tmpl = { > + .name = "eboiv", > + .create = eboiv_create, > + .module = THIS_MODULE, > +}; "cipher_name" => "cbc_cipher_name", since it wraps something like "cbc(aes)", not "aes". - Eric
