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![Ard Biesheuvel](/assets/img/avatar_default.png)
The cipher routines in the crypto API are mostly intended for templates implementing skcipher modes generically in software, and shouldn't be used outside of the crypto subsystem. So move the prototypes and all related definitions to a new header file under include/crypto/internal. Also, let's use the new module namespace feature to move the symbol exports into a new namespace CRYPTO_INTERNAL. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
195 lines
4.7 KiB
C
195 lines
4.7 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/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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