/* SPDX-License-Identifier: GPL-2.0-or-later *//* * CBC: Cipher Block Chaining mode * * Copyright (c) 2016 Herbert Xu <herbert@gondor.apana.org.au> */ #ifndef _CRYPTO_CBC_H#define _CRYPTO_CBC_H #include <crypto/internal/skcipher.h>#include <linux/string.h>#include <linux/types.h> static inline int crypto_cbc_encrypt_segment(	struct skcipher_walk *walk, struct crypto_skcipher *tfm,	void (*fn)(struct crypto_skcipher *, const u8 *, u8 *)){	unsigned int bsize = crypto_skcipher_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(tfm, iv, dst);		memcpy(iv, dst, bsize); 		src += bsize;		dst += bsize;	} while ((nbytes -= bsize) >= bsize); 	return nbytes;} static inline int crypto_cbc_encrypt_inplace(	struct skcipher_walk *walk, struct crypto_skcipher *tfm,	void (*fn)(struct crypto_skcipher *, const u8 *, u8 *)){	unsigned int bsize = crypto_skcipher_blocksize(tfm);	unsigned int nbytes = walk->nbytes;	u8 *src = walk->src.virt.addr;	u8 *iv = walk->iv; 	do {		crypto_xor(src, iv, bsize);		fn(tfm, src, src);		iv = src; 		src += bsize;	} while ((nbytes -= bsize) >= bsize); 	memcpy(walk->iv, iv, bsize); 	return nbytes;} static inline int crypto_cbc_encrypt_walk(struct skcipher_request *req,					  void (*fn)(struct crypto_skcipher *,						     const u8 *, u8 *)){	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);	struct skcipher_walk walk;	int err; 	err = skcipher_walk_virt(&walk, req, false); 	while (walk.nbytes) {		if (walk.src.virt.addr == walk.dst.virt.addr)			err = crypto_cbc_encrypt_inplace(&walk, tfm, fn);		else			err = crypto_cbc_encrypt_segment(&walk, tfm, fn);		err = skcipher_walk_done(&walk, err);	} 	return err;} static inline int crypto_cbc_decrypt_segment(	struct skcipher_walk *walk, struct crypto_skcipher *tfm,	void (*fn)(struct crypto_skcipher *, const u8 *, u8 *)){	unsigned int bsize = crypto_skcipher_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(tfm, src, dst);		crypto_xor(dst, iv, bsize);		iv = src; 		src += bsize;		dst += bsize;	} while ((nbytes -= bsize) >= bsize); 	memcpy(walk->iv, iv, bsize); 	return nbytes;} static inline int crypto_cbc_decrypt_inplace(	struct skcipher_walk *walk, struct crypto_skcipher *tfm,	void (*fn)(struct crypto_skcipher *, const u8 *, u8 *)){	unsigned int bsize = crypto_skcipher_blocksize(tfm);	unsigned int nbytes = walk->nbytes;	u8 *src = walk->src.virt.addr;	u8 last_iv[MAX_CIPHER_BLOCKSIZE]; 	/* Start of the last block. */	src += nbytes - (nbytes & (bsize - 1)) - bsize;	memcpy(last_iv, src, bsize); 	for (;;) {		fn(tfm, src, src);		if ((nbytes -= bsize) < bsize)			break;		crypto_xor(src, src - bsize, bsize);		src -= bsize;	} 	crypto_xor(src, walk->iv, bsize);	memcpy(walk->iv, last_iv, bsize); 	return nbytes;} static inline int crypto_cbc_decrypt_blocks(	struct skcipher_walk *walk, struct crypto_skcipher *tfm,	void (*fn)(struct crypto_skcipher *, const u8 *, u8 *)){	if (walk->src.virt.addr == walk->dst.virt.addr)		return crypto_cbc_decrypt_inplace(walk, tfm, fn);	else		return crypto_cbc_decrypt_segment(walk, tfm, fn);} #endif	/* _CRYPTO_CBC_H */