From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 11 Apr 2024 10:27:49 +0200 Subject: Adding upstream version 6.6.15. Signed-off-by: Daniel Baumann --- crypto/ofb.c | 106 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 106 insertions(+) create mode 100644 crypto/ofb.c (limited to 'crypto/ofb.c') diff --git a/crypto/ofb.c b/crypto/ofb.c new file mode 100644 index 0000000000..b630fdecce --- /dev/null +++ b/crypto/ofb.c @@ -0,0 +1,106 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * OFB: Output FeedBack mode + * + * Copyright (C) 2018 ARM Limited or its affiliates. + * All rights reserved. + */ + +#include +#include +#include +#include +#include +#include +#include + +static int crypto_ofb_crypt(struct skcipher_request *req) +{ + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + struct crypto_cipher *cipher = skcipher_cipher_simple(tfm); + const unsigned int bsize = crypto_cipher_blocksize(cipher); + struct skcipher_walk walk; + int err; + + err = skcipher_walk_virt(&walk, req, false); + + while (walk.nbytes >= bsize) { + const u8 *src = walk.src.virt.addr; + u8 *dst = walk.dst.virt.addr; + u8 * const iv = walk.iv; + unsigned int nbytes = walk.nbytes; + + do { + crypto_cipher_encrypt_one(cipher, iv, iv); + crypto_xor_cpy(dst, src, iv, bsize); + dst += bsize; + src += bsize; + } while ((nbytes -= bsize) >= bsize); + + err = skcipher_walk_done(&walk, nbytes); + } + + if (walk.nbytes) { + crypto_cipher_encrypt_one(cipher, walk.iv, walk.iv); + crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr, walk.iv, + walk.nbytes); + err = skcipher_walk_done(&walk, 0); + } + return err; +} + +static int crypto_ofb_create(struct crypto_template *tmpl, struct rtattr **tb) +{ + struct skcipher_instance *inst; + struct crypto_alg *alg; + int err; + + inst = skcipher_alloc_instance_simple(tmpl, tb); + if (IS_ERR(inst)) + return PTR_ERR(inst); + + alg = skcipher_ialg_simple(inst); + + /* OFB mode is a stream cipher. */ + inst->alg.base.cra_blocksize = 1; + + /* + * To simplify the implementation, configure the skcipher walk to only + * give a partial block at the very end, never earlier. + */ + inst->alg.chunksize = alg->cra_blocksize; + + inst->alg.encrypt = crypto_ofb_crypt; + inst->alg.decrypt = crypto_ofb_crypt; + + err = skcipher_register_instance(tmpl, inst); + if (err) + inst->free(inst); + + return err; +} + +static struct crypto_template crypto_ofb_tmpl = { + .name = "ofb", + .create = crypto_ofb_create, + .module = THIS_MODULE, +}; + +static int __init crypto_ofb_module_init(void) +{ + return crypto_register_template(&crypto_ofb_tmpl); +} + +static void __exit crypto_ofb_module_exit(void) +{ + crypto_unregister_template(&crypto_ofb_tmpl); +} + +subsys_initcall(crypto_ofb_module_init); +module_exit(crypto_ofb_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("OFB block cipher mode of operation"); +MODULE_ALIAS_CRYPTO("ofb"); +MODULE_IMPORT_NS(CRYPTO_INTERNAL); -- cgit v1.2.3