/* * 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/algapi.h>#include <linux/err.h>#include <linux/init.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/scatterlist.h>#include <linux/slab.h> struct crypto_pcbc_ctx {	struct crypto_cipher *child;}; static int crypto_pcbc_setkey(struct crypto_tfm *parent, const u8 *key,			      unsigned int keylen){	struct crypto_pcbc_ctx *ctx = crypto_tfm_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_tfm_get_flags(parent) &				CRYPTO_TFM_REQ_MASK);	err = crypto_cipher_setkey(child, key, keylen);	crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &			     CRYPTO_TFM_RES_MASK);	return err;} static int crypto_pcbc_encrypt_segment(struct blkcipher_desc *desc,				       struct blkcipher_walk *walk,				       struct crypto_cipher *tfm){	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =		crypto_cipher_alg(tfm)->cia_encrypt;	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);		fn(crypto_cipher_tfm(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 blkcipher_desc *desc,				       struct blkcipher_walk *walk,				       struct crypto_cipher *tfm){	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =		crypto_cipher_alg(tfm)->cia_encrypt;	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);		fn(crypto_cipher_tfm(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 blkcipher_desc *desc,			       struct scatterlist *dst, struct scatterlist *src,			       unsigned int nbytes){	struct blkcipher_walk walk;	struct crypto_blkcipher *tfm = desc->tfm;	struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);	struct crypto_cipher *child = ctx->child;	int err; 	blkcipher_walk_init(&walk, dst, src, nbytes);	err = blkcipher_walk_virt(desc, &walk); 	while ((nbytes = walk.nbytes)) {		if (walk.src.virt.addr == walk.dst.virt.addr)			nbytes = crypto_pcbc_encrypt_inplace(desc, &walk,							     child);		else			nbytes = crypto_pcbc_encrypt_segment(desc, &walk,							     child);		err = blkcipher_walk_done(desc, &walk, nbytes);	} 	return err;} static int crypto_pcbc_decrypt_segment(struct blkcipher_desc *desc,				       struct blkcipher_walk *walk,				       struct crypto_cipher *tfm){	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =		crypto_cipher_alg(tfm)->cia_decrypt;	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 {		fn(crypto_cipher_tfm(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 blkcipher_desc *desc,				       struct blkcipher_walk *walk,				       struct crypto_cipher *tfm){	void (*fn)(struct crypto_tfm *, u8 *, const u8 *) =		crypto_cipher_alg(tfm)->cia_decrypt;	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);		fn(crypto_cipher_tfm(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 blkcipher_desc *desc,			       struct scatterlist *dst, struct scatterlist *src,			       unsigned int nbytes){	struct blkcipher_walk walk;	struct crypto_blkcipher *tfm = desc->tfm;	struct crypto_pcbc_ctx *ctx = crypto_blkcipher_ctx(tfm);	struct crypto_cipher *child = ctx->child;	int err; 	blkcipher_walk_init(&walk, dst, src, nbytes);	err = blkcipher_walk_virt(desc, &walk); 	while ((nbytes = walk.nbytes)) {		if (walk.src.virt.addr == walk.dst.virt.addr)			nbytes = crypto_pcbc_decrypt_inplace(desc, &walk,							     child);		else			nbytes = crypto_pcbc_decrypt_segment(desc, &walk,							     child);		err = blkcipher_walk_done(desc, &walk, nbytes);	} 	return err;} static int crypto_pcbc_init_tfm(struct crypto_tfm *tfm){	struct crypto_instance *inst = (void *)tfm->__crt_alg;	struct crypto_spawn *spawn = crypto_instance_ctx(inst);	struct crypto_pcbc_ctx *ctx = crypto_tfm_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_tfm *tfm){	struct crypto_pcbc_ctx *ctx = crypto_tfm_ctx(tfm);	crypto_free_cipher(ctx->child);} static struct crypto_instance *crypto_pcbc_alloc(struct rtattr **tb){	struct crypto_instance *inst;	struct crypto_alg *alg;	int err; 	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);	if (err)		return ERR_PTR(err); 	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,				  CRYPTO_ALG_TYPE_MASK);	if (IS_ERR(alg))		return ERR_CAST(alg); 	inst = crypto_alloc_instance("pcbc", alg);	if (IS_ERR(inst))		goto out_put_alg; 	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;	inst->alg.cra_priority = alg->cra_priority;	inst->alg.cra_blocksize = alg->cra_blocksize;	inst->alg.cra_alignmask = alg->cra_alignmask;	inst->alg.cra_type = &crypto_blkcipher_type; 	/* We access the data as u32s when xoring. */	inst->alg.cra_alignmask |= __alignof__(u32) - 1; 	inst->alg.cra_blkcipher.ivsize = alg->cra_blocksize;	inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;	inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize; 	inst->alg.cra_ctxsize = sizeof(struct crypto_pcbc_ctx); 	inst->alg.cra_init = crypto_pcbc_init_tfm;	inst->alg.cra_exit = crypto_pcbc_exit_tfm; 	inst->alg.cra_blkcipher.setkey = crypto_pcbc_setkey;	inst->alg.cra_blkcipher.encrypt = crypto_pcbc_encrypt;	inst->alg.cra_blkcipher.decrypt = crypto_pcbc_decrypt; out_put_alg:	crypto_mod_put(alg);	return inst;} static void crypto_pcbc_free(struct crypto_instance *inst){	crypto_drop_spawn(crypto_instance_ctx(inst));	kfree(inst);} static struct crypto_template crypto_pcbc_tmpl = {	.name = "pcbc",	.alloc = crypto_pcbc_alloc,	.free = crypto_pcbc_free,	.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");