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195 lines
4.7 KiB
195 lines
4.7 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* PCBC: Propagating Cipher Block Chaining mode |
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* |
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* Copyright (C) 2006 Red Hat, Inc. All Rights Reserved. |
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* Written by David Howells ([email protected]) |
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* |
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* Derived from cbc.c |
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* - Copyright (c) 2006 Herbert Xu <[email protected]> |
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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_pcbc_encrypt_segment(struct skcipher_request *req, |
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struct skcipher_walk *walk, |
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struct crypto_cipher *tfm) |
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{ |
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int bsize = crypto_cipher_blocksize(tfm); |
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unsigned int nbytes = walk->nbytes; |
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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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do { |
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crypto_xor(iv, src, bsize); |
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crypto_cipher_encrypt_one(tfm, dst, iv); |
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crypto_xor_cpy(iv, dst, src, bsize); |
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src += bsize; |
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dst += bsize; |
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} while ((nbytes -= bsize) >= bsize); |
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return nbytes; |
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} |
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static int crypto_pcbc_encrypt_inplace(struct skcipher_request *req, |
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struct skcipher_walk *walk, |
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struct crypto_cipher *tfm) |
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{ |
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int bsize = crypto_cipher_blocksize(tfm); |
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unsigned int nbytes = walk->nbytes; |
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u8 *src = walk->src.virt.addr; |
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u8 * const iv = walk->iv; |
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u8 tmpbuf[MAX_CIPHER_BLOCKSIZE]; |
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do { |
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memcpy(tmpbuf, src, bsize); |
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crypto_xor(iv, src, bsize); |
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crypto_cipher_encrypt_one(tfm, src, iv); |
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crypto_xor_cpy(iv, tmpbuf, src, bsize); |
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src += bsize; |
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} while ((nbytes -= bsize) >= bsize); |
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return nbytes; |
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} |
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static int crypto_pcbc_encrypt(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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struct skcipher_walk walk; |
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unsigned int nbytes; |
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int err; |
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err = skcipher_walk_virt(&walk, req, false); |
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while ((nbytes = walk.nbytes)) { |
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if (walk.src.virt.addr == walk.dst.virt.addr) |
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nbytes = crypto_pcbc_encrypt_inplace(req, &walk, |
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cipher); |
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else |
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nbytes = crypto_pcbc_encrypt_segment(req, &walk, |
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cipher); |
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err = skcipher_walk_done(&walk, nbytes); |
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} |
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return err; |
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} |
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static int crypto_pcbc_decrypt_segment(struct skcipher_request *req, |
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struct skcipher_walk *walk, |
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struct crypto_cipher *tfm) |
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{ |
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int bsize = crypto_cipher_blocksize(tfm); |
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unsigned int nbytes = walk->nbytes; |
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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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do { |
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crypto_cipher_decrypt_one(tfm, dst, src); |
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crypto_xor(dst, iv, bsize); |
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crypto_xor_cpy(iv, dst, src, bsize); |
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src += bsize; |
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dst += bsize; |
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} while ((nbytes -= bsize) >= bsize); |
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return nbytes; |
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} |
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static int crypto_pcbc_decrypt_inplace(struct skcipher_request *req, |
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struct skcipher_walk *walk, |
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struct crypto_cipher *tfm) |
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{ |
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int bsize = crypto_cipher_blocksize(tfm); |
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unsigned int nbytes = walk->nbytes; |
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u8 *src = walk->src.virt.addr; |
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u8 * const iv = walk->iv; |
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u8 tmpbuf[MAX_CIPHER_BLOCKSIZE] __aligned(__alignof__(u32)); |
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do { |
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memcpy(tmpbuf, src, bsize); |
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crypto_cipher_decrypt_one(tfm, src, src); |
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crypto_xor(src, iv, bsize); |
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crypto_xor_cpy(iv, src, tmpbuf, bsize); |
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src += bsize; |
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} while ((nbytes -= bsize) >= bsize); |
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return nbytes; |
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} |
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static int crypto_pcbc_decrypt(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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struct skcipher_walk walk; |
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unsigned int nbytes; |
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int err; |
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err = skcipher_walk_virt(&walk, req, false); |
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while ((nbytes = walk.nbytes)) { |
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if (walk.src.virt.addr == walk.dst.virt.addr) |
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nbytes = crypto_pcbc_decrypt_inplace(req, &walk, |
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cipher); |
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else |
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nbytes = crypto_pcbc_decrypt_segment(req, &walk, |
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cipher); |
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err = skcipher_walk_done(&walk, nbytes); |
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} |
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return err; |
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} |
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static int crypto_pcbc_create(struct crypto_template *tmpl, struct rtattr **tb) |
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{ |
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struct skcipher_instance *inst; |
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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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inst->alg.encrypt = crypto_pcbc_encrypt; |
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inst->alg.decrypt = crypto_pcbc_decrypt; |
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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_pcbc_tmpl = { |
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.name = "pcbc", |
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.create = crypto_pcbc_create, |
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.module = THIS_MODULE, |
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}; |
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static int __init crypto_pcbc_module_init(void) |
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{ |
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return crypto_register_template(&crypto_pcbc_tmpl); |
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} |
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static void __exit crypto_pcbc_module_exit(void) |
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{ |
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crypto_unregister_template(&crypto_pcbc_tmpl); |
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} |
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subsys_initcall(crypto_pcbc_module_init); |
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module_exit(crypto_pcbc_module_exit); |
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MODULE_LICENSE("GPL"); |
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MODULE_DESCRIPTION("PCBC block cipher mode of operation"); |
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MODULE_ALIAS_CRYPTO("pcbc"); |
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MODULE_IMPORT_NS(CRYPTO_INTERNAL);
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