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0eb76ba29d
The cipher routines in the crypto API are mostly intended for templates implementing skcipher modes generically in software, and shouldn't be used outside of the crypto subsystem. So move the prototypes and all related definitions to a new header file under include/crypto/internal. Also, let's use the new module namespace feature to move the symbol exports into a new namespace CRYPTO_INTERNAL. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
107 lines
2.5 KiB
C
107 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* OFB: Output FeedBack mode
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*
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* Copyright (C) 2018 ARM Limited or its affiliates.
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* All rights reserved.
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*/
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#include <crypto/algapi.h>
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#include <crypto/internal/cipher.h>
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#include <crypto/internal/skcipher.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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static int crypto_ofb_crypt(struct skcipher_request *req)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
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const unsigned int bsize = crypto_cipher_blocksize(cipher);
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struct skcipher_walk walk;
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int err;
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err = skcipher_walk_virt(&walk, req, false);
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while (walk.nbytes >= bsize) {
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const u8 *src = walk.src.virt.addr;
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u8 *dst = walk.dst.virt.addr;
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u8 * const iv = walk.iv;
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unsigned int nbytes = walk.nbytes;
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do {
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crypto_cipher_encrypt_one(cipher, iv, iv);
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crypto_xor_cpy(dst, src, iv, bsize);
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dst += bsize;
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src += bsize;
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} while ((nbytes -= bsize) >= bsize);
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err = skcipher_walk_done(&walk, nbytes);
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}
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if (walk.nbytes) {
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crypto_cipher_encrypt_one(cipher, walk.iv, walk.iv);
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crypto_xor_cpy(walk.dst.virt.addr, walk.src.virt.addr, walk.iv,
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walk.nbytes);
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err = skcipher_walk_done(&walk, 0);
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}
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return err;
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}
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static int crypto_ofb_create(struct crypto_template *tmpl, struct rtattr **tb)
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{
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struct skcipher_instance *inst;
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struct crypto_alg *alg;
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int err;
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inst = skcipher_alloc_instance_simple(tmpl, tb);
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if (IS_ERR(inst))
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return PTR_ERR(inst);
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alg = skcipher_ialg_simple(inst);
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/* OFB mode is a stream cipher. */
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inst->alg.base.cra_blocksize = 1;
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/*
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* To simplify the implementation, configure the skcipher walk to only
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* give a partial block at the very end, never earlier.
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*/
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inst->alg.chunksize = alg->cra_blocksize;
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inst->alg.encrypt = crypto_ofb_crypt;
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inst->alg.decrypt = crypto_ofb_crypt;
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err = skcipher_register_instance(tmpl, inst);
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if (err)
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inst->free(inst);
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return err;
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}
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static struct crypto_template crypto_ofb_tmpl = {
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.name = "ofb",
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.create = crypto_ofb_create,
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.module = THIS_MODULE,
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};
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static int __init crypto_ofb_module_init(void)
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{
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return crypto_register_template(&crypto_ofb_tmpl);
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}
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static void __exit crypto_ofb_module_exit(void)
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{
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crypto_unregister_template(&crypto_ofb_tmpl);
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}
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subsys_initcall(crypto_ofb_module_init);
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module_exit(crypto_ofb_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("OFB block cipher mode of operation");
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MODULE_ALIAS_CRYPTO("ofb");
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MODULE_IMPORT_NS(CRYPTO_INTERNAL);
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