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![Herbert Xu](/assets/img/avatar_default.png)
Now that crypto/cbc.h is only used by the generic cbc template, we can merge it back into the CBC code. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
222 lines
5.1 KiB
C
222 lines
5.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* CBC: Cipher Block Chaining mode
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*
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* Copyright (c) 2006-2016 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/log2.h>
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#include <linux/module.h>
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static int crypto_cbc_encrypt_segment(struct skcipher_walk *walk,
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struct crypto_skcipher *skcipher)
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{
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unsigned int bsize = crypto_skcipher_blocksize(skcipher);
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void (*fn)(struct crypto_tfm *, u8 *, const u8 *);
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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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struct crypto_cipher *cipher;
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struct crypto_tfm *tfm;
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u8 *iv = walk->iv;
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cipher = skcipher_cipher_simple(skcipher);
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tfm = crypto_cipher_tfm(cipher);
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fn = crypto_cipher_alg(cipher)->cia_encrypt;
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do {
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crypto_xor(iv, src, bsize);
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fn(tfm, dst, iv);
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memcpy(iv, dst, 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_cbc_encrypt_inplace(struct skcipher_walk *walk,
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struct crypto_skcipher *skcipher)
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{
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unsigned int bsize = crypto_skcipher_blocksize(skcipher);
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void (*fn)(struct crypto_tfm *, u8 *, const u8 *);
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unsigned int nbytes = walk->nbytes;
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u8 *src = walk->src.virt.addr;
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struct crypto_cipher *cipher;
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struct crypto_tfm *tfm;
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u8 *iv = walk->iv;
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cipher = skcipher_cipher_simple(skcipher);
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tfm = crypto_cipher_tfm(cipher);
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fn = crypto_cipher_alg(cipher)->cia_encrypt;
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do {
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crypto_xor(src, iv, bsize);
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fn(tfm, src, src);
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iv = src;
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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_cbc_encrypt(struct skcipher_request *req)
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{
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struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
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struct skcipher_walk walk;
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int err;
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err = skcipher_walk_virt(&walk, req, false);
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while (walk.nbytes) {
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if (walk.src.virt.addr == walk.dst.virt.addr)
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err = crypto_cbc_encrypt_inplace(&walk, skcipher);
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else
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err = crypto_cbc_encrypt_segment(&walk, skcipher);
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err = skcipher_walk_done(&walk, err);
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}
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return err;
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}
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static int crypto_cbc_decrypt_segment(struct skcipher_walk *walk,
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struct crypto_skcipher *skcipher)
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{
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unsigned int bsize = crypto_skcipher_blocksize(skcipher);
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void (*fn)(struct crypto_tfm *, u8 *, const u8 *);
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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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struct crypto_cipher *cipher;
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struct crypto_tfm *tfm;
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u8 *iv = walk->iv;
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cipher = skcipher_cipher_simple(skcipher);
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tfm = crypto_cipher_tfm(cipher);
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fn = crypto_cipher_alg(cipher)->cia_decrypt;
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do {
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fn(tfm, dst, src);
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crypto_xor(dst, iv, bsize);
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iv = src;
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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_cbc_decrypt_inplace(struct skcipher_walk *walk,
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struct crypto_skcipher *skcipher)
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{
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unsigned int bsize = crypto_skcipher_blocksize(skcipher);
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void (*fn)(struct crypto_tfm *, u8 *, const u8 *);
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unsigned int nbytes = walk->nbytes;
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u8 *src = walk->src.virt.addr;
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u8 last_iv[MAX_CIPHER_BLOCKSIZE];
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struct crypto_cipher *cipher;
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struct crypto_tfm *tfm;
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cipher = skcipher_cipher_simple(skcipher);
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tfm = crypto_cipher_tfm(cipher);
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fn = crypto_cipher_alg(cipher)->cia_decrypt;
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/* Start of the last block. */
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src += nbytes - (nbytes & (bsize - 1)) - bsize;
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memcpy(last_iv, src, bsize);
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for (;;) {
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fn(tfm, src, src);
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if ((nbytes -= bsize) < bsize)
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break;
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crypto_xor(src, src - bsize, bsize);
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src -= bsize;
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}
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crypto_xor(src, walk->iv, bsize);
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memcpy(walk->iv, last_iv, bsize);
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return nbytes;
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}
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static int crypto_cbc_decrypt(struct skcipher_request *req)
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{
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struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
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struct skcipher_walk walk;
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int err;
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err = skcipher_walk_virt(&walk, req, false);
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while (walk.nbytes) {
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if (walk.src.virt.addr == walk.dst.virt.addr)
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err = crypto_cbc_decrypt_inplace(&walk, skcipher);
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else
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err = crypto_cbc_decrypt_segment(&walk, skcipher);
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err = skcipher_walk_done(&walk, err);
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}
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return err;
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}
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static int crypto_cbc_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_alg *alg;
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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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alg = skcipher_ialg_simple(inst);
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err = -EINVAL;
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if (!is_power_of_2(alg->cra_blocksize))
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goto out_free_inst;
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inst->alg.encrypt = crypto_cbc_encrypt;
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inst->alg.decrypt = crypto_cbc_decrypt;
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err = skcipher_register_instance(tmpl, inst);
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if (err) {
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out_free_inst:
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inst->free(inst);
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}
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return err;
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}
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static struct crypto_template crypto_cbc_tmpl = {
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.name = "cbc",
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.create = crypto_cbc_create,
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.module = THIS_MODULE,
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};
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static int __init crypto_cbc_module_init(void)
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{
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return crypto_register_template(&crypto_cbc_tmpl);
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}
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static void __exit crypto_cbc_module_exit(void)
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{
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crypto_unregister_template(&crypto_cbc_tmpl);
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}
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subsys_initcall(crypto_cbc_module_init);
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module_exit(crypto_cbc_module_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("CBC block cipher mode of operation");
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MODULE_ALIAS_CRYPTO("cbc");
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