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![Herbert Xu](/assets/img/avatar_default.png)
This patch introduces the skcipher_ialg_simple helper which fetches the crypto_alg structure from a simple skcipher instance's spawn. This allows us to remove the third argument from the function skcipher_alloc_instance_simple. In doing so the reference count to the algorithm is now maintained by the Crypto API and the caller no longer needs to drop the alg refcount. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
193 lines
4.6 KiB
C
193 lines
4.6 KiB
C
// 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 (dhowells@redhat.com)
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*
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* Derived from cbc.c
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* - Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
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*/
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#include <crypto/algapi.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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