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![Marcelo Cerri](/assets/img/avatar_default.png)
When requesting a fallback algorithm, we should propagate the NEED_FALLBACK bit when search for the underlying algorithm. This will prevents drivers from allocating unnecessary fallbacks that are never called. For instance, currently the vmx-crypto driver will use the following chain of calls when calling the fallback implementation: p8_aes_cbc -> cbc(p8_aes) -> aes-generic However p8_aes will always delegate its calls to aes-generic. With this patch, p8_aes_cbc will be able to use cbc(aes-generic) directly as its fallback. The same applies to aes_s390. Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
209 lines
5.1 KiB
C
209 lines
5.1 KiB
C
/*
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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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* 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/algapi.h>
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#include <crypto/cbc.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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#include <linux/slab.h>
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struct crypto_cbc_ctx {
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struct crypto_cipher *child;
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};
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static int crypto_cbc_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_cbc_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 inline void crypto_cbc_encrypt_one(struct crypto_skcipher *tfm,
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const u8 *src, u8 *dst)
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{
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struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
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crypto_cipher_encrypt_one(ctx->child, dst, src);
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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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return crypto_cbc_encrypt_walk(req, crypto_cbc_encrypt_one);
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}
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static inline void crypto_cbc_decrypt_one(struct crypto_skcipher *tfm,
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const u8 *src, u8 *dst)
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{
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struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
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crypto_cipher_decrypt_one(ctx->child, dst, src);
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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 *tfm = 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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err = crypto_cbc_decrypt_blocks(&walk, tfm,
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crypto_cbc_decrypt_one);
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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_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_cbc_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_cbc_exit_tfm(struct crypto_skcipher *tfm)
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{
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struct crypto_cbc_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_cbc_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_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_attr_type *algt;
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struct crypto_spawn *spawn;
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struct crypto_alg *alg;
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u32 mask;
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int err;
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err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER);
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if (err)
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return err;
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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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algt = crypto_get_attr_type(tb);
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err = PTR_ERR(algt);
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if (IS_ERR(algt))
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goto err_free_inst;
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mask = CRYPTO_ALG_TYPE_MASK |
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crypto_requires_off(algt->type, algt->mask,
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CRYPTO_ALG_NEED_FALLBACK);
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alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, mask);
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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), "cbc", alg);
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if (err)
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goto err_drop_spawn;
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err = -EINVAL;
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if (!is_power_of_2(alg->cra_blocksize))
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goto err_drop_spawn;
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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_cbc_ctx);
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inst->alg.init = crypto_cbc_init_tfm;
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inst->alg.exit = crypto_cbc_exit_tfm;
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inst->alg.setkey = crypto_cbc_setkey;
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inst->alg.encrypt = crypto_cbc_encrypt;
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inst->alg.decrypt = crypto_cbc_decrypt;
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inst->free = crypto_cbc_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_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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module_init(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 algorithm");
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MODULE_ALIAS_CRYPTO("cbc");
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