// SPDX-License-Identifier: GPL-2.0-or-later/* * PCBC: Propagating Cipher Block Chaining mode * * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * Derived from cbc.c * - Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au> */ #include <crypto/algapi.h>#include <crypto/internal/skcipher.h>#include <linux/err.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/module.h> static int crypto_pcbc_encrypt_segment(struct skcipher_request *req,				       struct skcipher_walk *walk,				       struct crypto_cipher *tfm){	int bsize = crypto_cipher_blocksize(tfm);	unsigned int nbytes = walk->nbytes;	u8 *src = walk->src.virt.addr;	u8 *dst = walk->dst.virt.addr;	u8 * const iv = walk->iv; 	do {		crypto_xor(iv, src, bsize);		crypto_cipher_encrypt_one(tfm, dst, iv);		crypto_xor_cpy(iv, dst, src, bsize); 		src += bsize;		dst += bsize;	} while ((nbytes -= bsize) >= bsize); 	return nbytes;} static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req,				       struct skcipher_walk *walk,				       struct crypto_cipher *tfm){	int bsize = crypto_cipher_blocksize(tfm);	unsigned int nbytes = walk->nbytes;	u8 *src = walk->src.virt.addr;	u8 * const iv = walk->iv;	u8 tmpbuf[MAX_CIPHER_BLOCKSIZE]; 	do {		memcpy(tmpbuf, src, bsize);		crypto_xor(iv, src, bsize);		crypto_cipher_encrypt_one(tfm, src, iv);		crypto_xor_cpy(iv, tmpbuf, src, bsize); 		src += bsize;	} while ((nbytes -= bsize) >= bsize); 	return nbytes;} static int crypto_pcbc_encrypt(struct skcipher_request *req){	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);	struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);	struct skcipher_walk walk;	unsigned int nbytes;	int err; 	err = skcipher_walk_virt(&walk, req, false); 	while ((nbytes = walk.nbytes)) {		if (walk.src.virt.addr == walk.dst.virt.addr)			nbytes = crypto_pcbc_encrypt_inplace(req, &walk,							     cipher);		else			nbytes = crypto_pcbc_encrypt_segment(req, &walk,							     cipher);		err = skcipher_walk_done(&walk, nbytes);	} 	return err;} static int crypto_pcbc_decrypt_segment(struct skcipher_request *req,				       struct skcipher_walk *walk,				       struct crypto_cipher *tfm){	int bsize = crypto_cipher_blocksize(tfm);	unsigned int nbytes = walk->nbytes;	u8 *src = walk->src.virt.addr;	u8 *dst = walk->dst.virt.addr;	u8 * const iv = walk->iv; 	do {		crypto_cipher_decrypt_one(tfm, dst, src);		crypto_xor(dst, iv, bsize);		crypto_xor_cpy(iv, dst, src, bsize); 		src += bsize;		dst += bsize;	} while ((nbytes -= bsize) >= bsize); 	return nbytes;} static int crypto_pcbc_decrypt_inplace(struct skcipher_request *req,				       struct skcipher_walk *walk,				       struct crypto_cipher *tfm){	int bsize = crypto_cipher_blocksize(tfm);	unsigned int nbytes = walk->nbytes;	u8 *src = walk->src.virt.addr;	u8 * const iv = walk->iv;	u8 tmpbuf[MAX_CIPHER_BLOCKSIZE] __aligned(__alignof__(u32)); 	do {		memcpy(tmpbuf, src, bsize);		crypto_cipher_decrypt_one(tfm, src, src);		crypto_xor(src, iv, bsize);		crypto_xor_cpy(iv, src, tmpbuf, bsize); 		src += bsize;	} while ((nbytes -= bsize) >= bsize); 	return nbytes;} static int crypto_pcbc_decrypt(struct skcipher_request *req){	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);	struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);	struct skcipher_walk walk;	unsigned int nbytes;	int err; 	err = skcipher_walk_virt(&walk, req, false); 	while ((nbytes = walk.nbytes)) {		if (walk.src.virt.addr == walk.dst.virt.addr)			nbytes = crypto_pcbc_decrypt_inplace(req, &walk,							     cipher);		else			nbytes = crypto_pcbc_decrypt_segment(req, &walk,							     cipher);		err = skcipher_walk_done(&walk, nbytes);	} 	return err;} static int crypto_pcbc_create(struct crypto_template *tmpl, struct rtattr **tb){	struct skcipher_instance *inst;	int err; 	inst = skcipher_alloc_instance_simple(tmpl, tb);	if (IS_ERR(inst))		return PTR_ERR(inst); 	inst->alg.encrypt = crypto_pcbc_encrypt;	inst->alg.decrypt = crypto_pcbc_decrypt; 	err = skcipher_register_instance(tmpl, inst);	if (err)		inst->free(inst); 	return err;} static struct crypto_template crypto_pcbc_tmpl = {	.name = "pcbc",	.create = crypto_pcbc_create,	.module = THIS_MODULE,}; static int __init crypto_pcbc_module_init(void){	return crypto_register_template(&crypto_pcbc_tmpl);} static void __exit crypto_pcbc_module_exit(void){	crypto_unregister_template(&crypto_pcbc_tmpl);} subsys_initcall(crypto_pcbc_module_init);module_exit(crypto_pcbc_module_exit); MODULE_LICENSE("GPL");MODULE_DESCRIPTION("PCBC block cipher mode of operation");MODULE_ALIAS_CRYPTO("pcbc");