/* * 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> * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the Free * Software Foundation; either version 2 of the License, or (at your option) * any later version. * */ #include <crypto/internal/skcipher.h>#include <linux/err.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/slab.h>#include <linux/compiler.h> struct crypto_pcbc_ctx {	struct crypto_cipher *child;}; static int crypto_pcbc_setkey(struct crypto_skcipher *parent, const u8 *key,			      unsigned int keylen){	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(parent);	struct crypto_cipher *child = ctx->child;	int err; 	crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);	crypto_cipher_set_flags(child, crypto_skcipher_get_flags(parent) &				       CRYPTO_TFM_REQ_MASK);	err = crypto_cipher_setkey(child, key, keylen);	crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(child) &					  CRYPTO_TFM_RES_MASK);	return err;} 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 *iv = walk->iv; 	do {		crypto_xor(iv, src, bsize);		crypto_cipher_encrypt_one(tfm, dst, iv);		memcpy(iv, dst, bsize);		crypto_xor(iv, 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 *iv = walk->iv;	u8 tmpbuf[bsize]; 	do {		memcpy(tmpbuf, src, bsize);		crypto_xor(iv, src, bsize);		crypto_cipher_encrypt_one(tfm, src, iv);		memcpy(iv, tmpbuf, bsize);		crypto_xor(iv, src, bsize); 		src += bsize;	} while ((nbytes -= bsize) >= bsize); 	memcpy(walk->iv, iv, bsize); 	return nbytes;} static int crypto_pcbc_encrypt(struct skcipher_request *req){	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);	struct crypto_cipher *child = ctx->child;	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,							     child);		else			nbytes = crypto_pcbc_encrypt_segment(req, &walk,							     child);		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 *iv = walk->iv; 	do {		crypto_cipher_decrypt_one(tfm, dst, src);		crypto_xor(dst, iv, bsize);		memcpy(iv, src, bsize);		crypto_xor(iv, dst, bsize); 		src += bsize;		dst += bsize;	} while ((nbytes -= bsize) >= bsize); 	memcpy(walk->iv, iv, 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 *iv = walk->iv;	u8 tmpbuf[bsize] __aligned(__alignof__(u32)); 	do {		memcpy(tmpbuf, src, bsize);		crypto_cipher_decrypt_one(tfm, src, src);		crypto_xor(src, iv, bsize);		memcpy(iv, tmpbuf, bsize);		crypto_xor(iv, src, bsize); 		src += bsize;	} while ((nbytes -= bsize) >= bsize); 	memcpy(walk->iv, iv, bsize); 	return nbytes;} static int crypto_pcbc_decrypt(struct skcipher_request *req){	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);	struct crypto_cipher *child = ctx->child;	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,							     child);		else			nbytes = crypto_pcbc_decrypt_segment(req, &walk,							     child);		err = skcipher_walk_done(&walk, nbytes);	} 	return err;} static int crypto_pcbc_init_tfm(struct crypto_skcipher *tfm){	struct skcipher_instance *inst = skcipher_alg_instance(tfm);	struct crypto_spawn *spawn = skcipher_instance_ctx(inst);	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);	struct crypto_cipher *cipher; 	cipher = crypto_spawn_cipher(spawn);	if (IS_ERR(cipher))		return PTR_ERR(cipher); 	ctx->child = cipher;	return 0;} static void crypto_pcbc_exit_tfm(struct crypto_skcipher *tfm){	struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm); 	crypto_free_cipher(ctx->child);} static void crypto_pcbc_free(struct skcipher_instance *inst){	crypto_drop_skcipher(skcipher_instance_ctx(inst));	kfree(inst);} static int crypto_pcbc_create(struct crypto_template *tmpl, struct rtattr **tb){	struct skcipher_instance *inst;	struct crypto_attr_type *algt;	struct crypto_spawn *spawn;	struct crypto_alg *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) &	    ~CRYPTO_ALG_INTERNAL)		return -EINVAL; 	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);	if (!inst)		return -ENOMEM; 	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER |				      (algt->type & CRYPTO_ALG_INTERNAL),				  CRYPTO_ALG_TYPE_MASK |				  (algt->mask & CRYPTO_ALG_INTERNAL));	err = PTR_ERR(alg);	if (IS_ERR(alg))		goto err_free_inst; 	spawn = skcipher_instance_ctx(inst);	err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),				CRYPTO_ALG_TYPE_MASK);	crypto_mod_put(alg);	if (err)		goto err_free_inst; 	err = crypto_inst_setname(skcipher_crypto_instance(inst), "pcbc", alg);	if (err)		goto err_drop_spawn; 	inst->alg.base.cra_flags = alg->cra_flags & CRYPTO_ALG_INTERNAL;	inst->alg.base.cra_priority = alg->cra_priority;	inst->alg.base.cra_blocksize = alg->cra_blocksize;	inst->alg.base.cra_alignmask = alg->cra_alignmask; 	inst->alg.ivsize = alg->cra_blocksize;	inst->alg.min_keysize = alg->cra_cipher.cia_min_keysize;	inst->alg.max_keysize = alg->cra_cipher.cia_max_keysize; 	inst->alg.base.cra_ctxsize = sizeof(struct crypto_pcbc_ctx); 	inst->alg.init = crypto_pcbc_init_tfm;	inst->alg.exit = crypto_pcbc_exit_tfm; 	inst->alg.setkey = crypto_pcbc_setkey;	inst->alg.encrypt = crypto_pcbc_encrypt;	inst->alg.decrypt = crypto_pcbc_decrypt; 	inst->free = crypto_pcbc_free; 	err = skcipher_register_instance(tmpl, inst);	if (err)		goto err_drop_spawn; out:	return err; err_drop_spawn:	crypto_drop_spawn(spawn);err_free_inst:	kfree(inst);	goto out;} 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);} module_init(crypto_pcbc_module_init);module_exit(crypto_pcbc_module_exit); MODULE_LICENSE("GPL");MODULE_DESCRIPTION("PCBC block cipher algorithm");MODULE_ALIAS_CRYPTO("pcbc");