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![Ard Biesheuvel](/assets/img/avatar_default.png)
There are quite a number of occurrences in the kernel of the pattern if (dst != src) memcpy(dst, src, walk.total % AES_BLOCK_SIZE); crypto_xor(dst, final, walk.total % AES_BLOCK_SIZE); or crypto_xor(keystream, src, nbytes); memcpy(dst, keystream, nbytes); where crypto_xor() is preceded or followed by a memcpy() invocation that is only there because crypto_xor() uses its output parameter as one of the inputs. To avoid having to add new instances of this pattern in the arm64 code, which will be refactored to implement non-SIMD fallbacks, add an alternative implementation called crypto_xor_cpy(), taking separate input and output arguments. This removes the need for the separate memcpy(). Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
309 lines
7.7 KiB
C
309 lines
7.7 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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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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#include <linux/slab.h>
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#include <linux/compiler.h>
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struct crypto_pcbc_ctx {
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struct crypto_cipher *child;
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};
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static int crypto_pcbc_setkey(struct crypto_skcipher *parent, const u8 *key,
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unsigned int keylen)
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{
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struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(parent);
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struct crypto_cipher *child = ctx->child;
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int err;
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crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
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crypto_cipher_set_flags(child, crypto_skcipher_get_flags(parent) &
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CRYPTO_TFM_REQ_MASK);
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err = crypto_cipher_setkey(child, key, keylen);
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crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(child) &
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CRYPTO_TFM_RES_MASK);
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return err;
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}
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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 *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 *iv = walk->iv;
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u8 tmpbuf[bsize];
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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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memcpy(walk->iv, iv, 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_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
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struct crypto_cipher *child = ctx->child;
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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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child);
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else
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nbytes = crypto_pcbc_encrypt_segment(req, &walk,
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child);
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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 *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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memcpy(walk->iv, iv, 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 *iv = walk->iv;
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u8 tmpbuf[bsize] __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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memcpy(walk->iv, iv, 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_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
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struct crypto_cipher *child = ctx->child;
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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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child);
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else
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nbytes = crypto_pcbc_decrypt_segment(req, &walk,
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child);
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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_init_tfm(struct crypto_skcipher *tfm)
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{
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struct skcipher_instance *inst = skcipher_alg_instance(tfm);
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struct crypto_spawn *spawn = skcipher_instance_ctx(inst);
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struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
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struct crypto_cipher *cipher;
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cipher = crypto_spawn_cipher(spawn);
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if (IS_ERR(cipher))
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return PTR_ERR(cipher);
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ctx->child = cipher;
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return 0;
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}
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static void crypto_pcbc_exit_tfm(struct crypto_skcipher *tfm)
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{
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struct crypto_pcbc_ctx *ctx = crypto_skcipher_ctx(tfm);
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crypto_free_cipher(ctx->child);
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}
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static void crypto_pcbc_free(struct skcipher_instance *inst)
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{
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crypto_drop_skcipher(skcipher_instance_ctx(inst));
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kfree(inst);
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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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struct crypto_attr_type *algt;
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struct crypto_spawn *spawn;
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struct crypto_alg *alg;
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int err;
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algt = crypto_get_attr_type(tb);
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if (IS_ERR(algt))
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return PTR_ERR(algt);
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if (((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask) &
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~CRYPTO_ALG_INTERNAL)
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return -EINVAL;
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inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
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if (!inst)
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return -ENOMEM;
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alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER |
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(algt->type & CRYPTO_ALG_INTERNAL),
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CRYPTO_ALG_TYPE_MASK |
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(algt->mask & CRYPTO_ALG_INTERNAL));
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err = PTR_ERR(alg);
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if (IS_ERR(alg))
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goto err_free_inst;
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spawn = skcipher_instance_ctx(inst);
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err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst),
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CRYPTO_ALG_TYPE_MASK);
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crypto_mod_put(alg);
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if (err)
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goto err_free_inst;
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err = crypto_inst_setname(skcipher_crypto_instance(inst), "pcbc", alg);
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if (err)
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goto err_drop_spawn;
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inst->alg.base.cra_flags = alg->cra_flags & CRYPTO_ALG_INTERNAL;
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inst->alg.base.cra_priority = alg->cra_priority;
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inst->alg.base.cra_blocksize = alg->cra_blocksize;
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inst->alg.base.cra_alignmask = alg->cra_alignmask;
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inst->alg.ivsize = alg->cra_blocksize;
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inst->alg.min_keysize = alg->cra_cipher.cia_min_keysize;
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inst->alg.max_keysize = alg->cra_cipher.cia_max_keysize;
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inst->alg.base.cra_ctxsize = sizeof(struct crypto_pcbc_ctx);
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inst->alg.init = crypto_pcbc_init_tfm;
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inst->alg.exit = crypto_pcbc_exit_tfm;
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inst->alg.setkey = crypto_pcbc_setkey;
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inst->alg.encrypt = crypto_pcbc_encrypt;
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inst->alg.decrypt = crypto_pcbc_decrypt;
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inst->free = crypto_pcbc_free;
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err = skcipher_register_instance(tmpl, inst);
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if (err)
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goto err_drop_spawn;
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out:
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return err;
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err_drop_spawn:
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crypto_drop_spawn(spawn);
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err_free_inst:
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kfree(inst);
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goto out;
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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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module_init(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 algorithm");
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MODULE_ALIAS_CRYPTO("pcbc");
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