/*
   * Symmetric key cipher operations.
   *
   * Generic encrypt/decrypt wrapper for ciphers, handles operations across
   * multiple page boundaries by using temporary blocks.  In user context,
   * the kernel is given a chance to schedule us once per page.
   *
   * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au>
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License as published by the Free
   * Software Foundation; either version 2 of the License, or (at your option)
   * any later version.
   *
   */
  
  #include <crypto/internal/skcipher.h>
  #include <linux/bug.h>

  #include <linux/cryptouser.h>

  #include <linux/module.h>

  #include <linux/rtnetlink.h>
  #include <linux/seq_file.h>
  #include <net/netlink.h>

  
  #include "internal.h"
  
  static unsigned int crypto_skcipher_extsize(struct crypto_alg *alg)
  {
  	if (alg->cra_type == &crypto_blkcipher_type)
  		return sizeof(struct crypto_blkcipher *);

  	if (alg->cra_type == &crypto_ablkcipher_type ||
  	    alg->cra_type == &crypto_givcipher_type)
  		return sizeof(struct crypto_ablkcipher *);

  	return crypto_alg_extsize(alg);

  }
  
  static int skcipher_setkey_blkcipher(struct crypto_skcipher *tfm,
  				     const u8 *key, unsigned int keylen)
  {
  	struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm);
  	struct crypto_blkcipher *blkcipher = *ctx;
  	int err;
  
  	crypto_blkcipher_clear_flags(blkcipher, ~0);
  	crypto_blkcipher_set_flags(blkcipher, crypto_skcipher_get_flags(tfm) &
  					      CRYPTO_TFM_REQ_MASK);
  	err = crypto_blkcipher_setkey(blkcipher, key, keylen);
  	crypto_skcipher_set_flags(tfm, crypto_blkcipher_get_flags(blkcipher) &
  				       CRYPTO_TFM_RES_MASK);
  
  	return err;
  }
  
  static int skcipher_crypt_blkcipher(struct skcipher_request *req,
  				    int (*crypt)(struct blkcipher_desc *,
  						 struct scatterlist *,
  						 struct scatterlist *,
  						 unsigned int))
  {
  	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  	struct crypto_blkcipher **ctx = crypto_skcipher_ctx(tfm);
  	struct blkcipher_desc desc = {
  		.tfm = *ctx,
  		.info = req->iv,
  		.flags = req->base.flags,
  	};
  
  
  	return crypt(&desc, req->dst, req->src, req->cryptlen);
  }
  
  static int skcipher_encrypt_blkcipher(struct skcipher_request *req)
  {
  	struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
  	struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
  	struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
  
  	return skcipher_crypt_blkcipher(req, alg->encrypt);
  }
  
  static int skcipher_decrypt_blkcipher(struct skcipher_request *req)
  {
  	struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
  	struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
  	struct blkcipher_alg *alg = &tfm->__crt_alg->cra_blkcipher;
  
  	return skcipher_crypt_blkcipher(req, alg->decrypt);
  }
  
  static void crypto_exit_skcipher_ops_blkcipher(struct crypto_tfm *tfm)
  {
  	struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm);
  
  	crypto_free_blkcipher(*ctx);
  }

  static int crypto_init_skcipher_ops_blkcipher(struct crypto_tfm *tfm)

  {
  	struct crypto_alg *calg = tfm->__crt_alg;
  	struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
  	struct crypto_blkcipher **ctx = crypto_tfm_ctx(tfm);
  	struct crypto_blkcipher *blkcipher;
  	struct crypto_tfm *btfm;
  
  	if (!crypto_mod_get(calg))
  		return -EAGAIN;
  
  	btfm = __crypto_alloc_tfm(calg, CRYPTO_ALG_TYPE_BLKCIPHER,
  					CRYPTO_ALG_TYPE_MASK);
  	if (IS_ERR(btfm)) {
  		crypto_mod_put(calg);
  		return PTR_ERR(btfm);
  	}
  
  	blkcipher = __crypto_blkcipher_cast(btfm);
  	*ctx = blkcipher;
  	tfm->exit = crypto_exit_skcipher_ops_blkcipher;
  
  	skcipher->setkey = skcipher_setkey_blkcipher;
  	skcipher->encrypt = skcipher_encrypt_blkcipher;
  	skcipher->decrypt = skcipher_decrypt_blkcipher;
  
  	skcipher->ivsize = crypto_blkcipher_ivsize(blkcipher);

  	skcipher->keysize = calg->cra_blkcipher.max_keysize;

  
  	return 0;
  }
  
  static int skcipher_setkey_ablkcipher(struct crypto_skcipher *tfm,
  				      const u8 *key, unsigned int keylen)
  {
  	struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm);
  	struct crypto_ablkcipher *ablkcipher = *ctx;
  	int err;
  
  	crypto_ablkcipher_clear_flags(ablkcipher, ~0);
  	crypto_ablkcipher_set_flags(ablkcipher,
  				    crypto_skcipher_get_flags(tfm) &
  				    CRYPTO_TFM_REQ_MASK);
  	err = crypto_ablkcipher_setkey(ablkcipher, key, keylen);
  	crypto_skcipher_set_flags(tfm,
  				  crypto_ablkcipher_get_flags(ablkcipher) &
  				  CRYPTO_TFM_RES_MASK);
  
  	return err;
  }
  
  static int skcipher_crypt_ablkcipher(struct skcipher_request *req,
  				     int (*crypt)(struct ablkcipher_request *))
  {
  	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  	struct crypto_ablkcipher **ctx = crypto_skcipher_ctx(tfm);
  	struct ablkcipher_request *subreq = skcipher_request_ctx(req);
  
  	ablkcipher_request_set_tfm(subreq, *ctx);
  	ablkcipher_request_set_callback(subreq, skcipher_request_flags(req),
  					req->base.complete, req->base.data);
  	ablkcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
  				     req->iv);
  
  	return crypt(subreq);
  }
  
  static int skcipher_encrypt_ablkcipher(struct skcipher_request *req)
  {
  	struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
  	struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
  	struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
  
  	return skcipher_crypt_ablkcipher(req, alg->encrypt);
  }
  
  static int skcipher_decrypt_ablkcipher(struct skcipher_request *req)
  {
  	struct crypto_skcipher *skcipher = crypto_skcipher_reqtfm(req);
  	struct crypto_tfm *tfm = crypto_skcipher_tfm(skcipher);
  	struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
  
  	return skcipher_crypt_ablkcipher(req, alg->decrypt);
  }
  
  static void crypto_exit_skcipher_ops_ablkcipher(struct crypto_tfm *tfm)
  {
  	struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm);
  
  	crypto_free_ablkcipher(*ctx);
  }

  static int crypto_init_skcipher_ops_ablkcipher(struct crypto_tfm *tfm)

  {
  	struct crypto_alg *calg = tfm->__crt_alg;
  	struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
  	struct crypto_ablkcipher **ctx = crypto_tfm_ctx(tfm);
  	struct crypto_ablkcipher *ablkcipher;
  	struct crypto_tfm *abtfm;
  
  	if (!crypto_mod_get(calg))
  		return -EAGAIN;
  
  	abtfm = __crypto_alloc_tfm(calg, 0, 0);
  	if (IS_ERR(abtfm)) {
  		crypto_mod_put(calg);
  		return PTR_ERR(abtfm);
  	}
  
  	ablkcipher = __crypto_ablkcipher_cast(abtfm);
  	*ctx = ablkcipher;
  	tfm->exit = crypto_exit_skcipher_ops_ablkcipher;
  
  	skcipher->setkey = skcipher_setkey_ablkcipher;
  	skcipher->encrypt = skcipher_encrypt_ablkcipher;
  	skcipher->decrypt = skcipher_decrypt_ablkcipher;
  
  	skcipher->ivsize = crypto_ablkcipher_ivsize(ablkcipher);
  	skcipher->reqsize = crypto_ablkcipher_reqsize(ablkcipher) +
  			    sizeof(struct ablkcipher_request);

  	skcipher->keysize = calg->cra_ablkcipher.max_keysize;

  
  	return 0;
  }

  static void crypto_skcipher_exit_tfm(struct crypto_tfm *tfm)
  {
  	struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
  	struct skcipher_alg *alg = crypto_skcipher_alg(skcipher);
  
  	alg->exit(skcipher);
  }

  static int crypto_skcipher_init_tfm(struct crypto_tfm *tfm)
  {

  	struct crypto_skcipher *skcipher = __crypto_skcipher_cast(tfm);
  	struct skcipher_alg *alg = crypto_skcipher_alg(skcipher);

  	if (tfm->__crt_alg->cra_type == &crypto_blkcipher_type)
  		return crypto_init_skcipher_ops_blkcipher(tfm);

  	if (tfm->__crt_alg->cra_type == &crypto_ablkcipher_type ||
  	    tfm->__crt_alg->cra_type == &crypto_givcipher_type)
  		return crypto_init_skcipher_ops_ablkcipher(tfm);
  
  	skcipher->setkey = alg->setkey;
  	skcipher->encrypt = alg->encrypt;
  	skcipher->decrypt = alg->decrypt;
  	skcipher->ivsize = alg->ivsize;
  	skcipher->keysize = alg->max_keysize;
  
  	if (alg->exit)
  		skcipher->base.exit = crypto_skcipher_exit_tfm;

  	if (alg->init)
  		return alg->init(skcipher);
  
  	return 0;
  }
  
  static void crypto_skcipher_free_instance(struct crypto_instance *inst)
  {
  	struct skcipher_instance *skcipher =
  		container_of(inst, struct skcipher_instance, s.base);
  
  	skcipher->free(skcipher);
  }
  
  static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)
  	__attribute__ ((unused));
  static void crypto_skcipher_show(struct seq_file *m, struct crypto_alg *alg)
  {
  	struct skcipher_alg *skcipher = container_of(alg, struct skcipher_alg,
  						     base);
  
  	seq_printf(m, "type         : skcipher
  ");
  	seq_printf(m, "async        : %s
  ",
  		   alg->cra_flags & CRYPTO_ALG_ASYNC ?  "yes" : "no");
  	seq_printf(m, "blocksize    : %u
  ", alg->cra_blocksize);
  	seq_printf(m, "min keysize  : %u
  ", skcipher->min_keysize);
  	seq_printf(m, "max keysize  : %u
  ", skcipher->max_keysize);
  	seq_printf(m, "ivsize       : %u
  ", skcipher->ivsize);
  	seq_printf(m, "chunksize    : %u
  ", skcipher->chunksize);

  }

  #ifdef CONFIG_NET
  static int crypto_skcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
  {
  	struct crypto_report_blkcipher rblkcipher;
  	struct skcipher_alg *skcipher = container_of(alg, struct skcipher_alg,
  						     base);
  
  	strncpy(rblkcipher.type, "skcipher", sizeof(rblkcipher.type));
  	strncpy(rblkcipher.geniv, "<none>", sizeof(rblkcipher.geniv));
  
  	rblkcipher.blocksize = alg->cra_blocksize;
  	rblkcipher.min_keysize = skcipher->min_keysize;
  	rblkcipher.max_keysize = skcipher->max_keysize;
  	rblkcipher.ivsize = skcipher->ivsize;
  
  	if (nla_put(skb, CRYPTOCFGA_REPORT_BLKCIPHER,
  		    sizeof(struct crypto_report_blkcipher), &rblkcipher))
  		goto nla_put_failure;
  	return 0;
  
  nla_put_failure:
  	return -EMSGSIZE;
  }
  #else
  static int crypto_skcipher_report(struct sk_buff *skb, struct crypto_alg *alg)
  {
  	return -ENOSYS;
  }
  #endif

  static const struct crypto_type crypto_skcipher_type2 = {
  	.extsize = crypto_skcipher_extsize,
  	.init_tfm = crypto_skcipher_init_tfm,

  	.free = crypto_skcipher_free_instance,
  #ifdef CONFIG_PROC_FS
  	.show = crypto_skcipher_show,
  #endif
  	.report = crypto_skcipher_report,

  	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
  	.maskset = CRYPTO_ALG_TYPE_BLKCIPHER_MASK,

  	.type = CRYPTO_ALG_TYPE_SKCIPHER,

  	.tfmsize = offsetof(struct crypto_skcipher, base),
  };

  int crypto_grab_skcipher(struct crypto_skcipher_spawn *spawn,

  			  const char *name, u32 type, u32 mask)
  {
  	spawn->base.frontend = &crypto_skcipher_type2;
  	return crypto_grab_spawn(&spawn->base, name, type, mask);
  }

  EXPORT_SYMBOL_GPL(crypto_grab_skcipher);

  struct crypto_skcipher *crypto_alloc_skcipher(const char *alg_name,
  					      u32 type, u32 mask)
  {
  	return crypto_alloc_tfm(alg_name, &crypto_skcipher_type2, type, mask);
  }
  EXPORT_SYMBOL_GPL(crypto_alloc_skcipher);

  int crypto_has_skcipher2(const char *alg_name, u32 type, u32 mask)
  {
  	return crypto_type_has_alg(alg_name, &crypto_skcipher_type2,
  				   type, mask);
  }
  EXPORT_SYMBOL_GPL(crypto_has_skcipher2);
  
  static int skcipher_prepare_alg(struct skcipher_alg *alg)
  {
  	struct crypto_alg *base = &alg->base;
  
  	if (alg->ivsize > PAGE_SIZE / 8 || alg->chunksize > PAGE_SIZE / 8)
  		return -EINVAL;
  
  	if (!alg->chunksize)
  		alg->chunksize = base->cra_blocksize;
  
  	base->cra_type = &crypto_skcipher_type2;
  	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
  	base->cra_flags |= CRYPTO_ALG_TYPE_SKCIPHER;
  
  	return 0;
  }
  
  int crypto_register_skcipher(struct skcipher_alg *alg)
  {
  	struct crypto_alg *base = &alg->base;
  	int err;
  
  	err = skcipher_prepare_alg(alg);
  	if (err)
  		return err;
  
  	return crypto_register_alg(base);
  }
  EXPORT_SYMBOL_GPL(crypto_register_skcipher);
  
  void crypto_unregister_skcipher(struct skcipher_alg *alg)
  {
  	crypto_unregister_alg(&alg->base);
  }
  EXPORT_SYMBOL_GPL(crypto_unregister_skcipher);
  
  int crypto_register_skciphers(struct skcipher_alg *algs, int count)
  {
  	int i, ret;
  
  	for (i = 0; i < count; i++) {
  		ret = crypto_register_skcipher(&algs[i]);
  		if (ret)
  			goto err;
  	}
  
  	return 0;
  
  err:
  	for (--i; i >= 0; --i)
  		crypto_unregister_skcipher(&algs[i]);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(crypto_register_skciphers);
  
  void crypto_unregister_skciphers(struct skcipher_alg *algs, int count)
  {
  	int i;
  
  	for (i = count - 1; i >= 0; --i)
  		crypto_unregister_skcipher(&algs[i]);
  }
  EXPORT_SYMBOL_GPL(crypto_unregister_skciphers);
  
  int skcipher_register_instance(struct crypto_template *tmpl,
  			   struct skcipher_instance *inst)
  {
  	int err;
  
  	err = skcipher_prepare_alg(&inst->alg);
  	if (err)
  		return err;
  
  	return crypto_register_instance(tmpl, skcipher_crypto_instance(inst));
  }
  EXPORT_SYMBOL_GPL(skcipher_register_instance);

  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Symmetric key cipher type");