/*
   * AEAD: Authenticated Encryption with Associated Data

   *

   * This file provides API support for AEAD algorithms.
   *

   * Copyright (c) 2007-2015 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/geniv.h>

  #include <crypto/internal/rng.h>
  #include <crypto/null.h>

  #include <crypto/scatterwalk.h>

  #include <linux/err.h>

  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/module.h>

  #include <linux/rtnetlink.h>

  #include <linux/slab.h>
  #include <linux/seq_file.h>

  #include <linux/cryptouser.h>
  #include <net/netlink.h>

  #include "internal.h"

  static int setkey_unaligned(struct crypto_aead *tfm, const u8 *key,
  			    unsigned int keylen)
  {

  	unsigned long alignmask = crypto_aead_alignmask(tfm);
  	int ret;
  	u8 *buffer, *alignbuffer;
  	unsigned long absize;
  
  	absize = keylen + alignmask;
  	buffer = kmalloc(absize, GFP_ATOMIC);
  	if (!buffer)
  		return -ENOMEM;
  
  	alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  	memcpy(alignbuffer, key, keylen);

  	ret = crypto_aead_alg(tfm)->setkey(tfm, alignbuffer, keylen);

  	memset(alignbuffer, 0, keylen);
  	kfree(buffer);
  	return ret;
  }

  int crypto_aead_setkey(struct crypto_aead *tfm,
  		       const u8 *key, unsigned int keylen)

  {

  	unsigned long alignmask = crypto_aead_alignmask(tfm);
  
  	if ((unsigned long)key & alignmask)
  		return setkey_unaligned(tfm, key, keylen);

  	return crypto_aead_alg(tfm)->setkey(tfm, key, keylen);

  }

  EXPORT_SYMBOL_GPL(crypto_aead_setkey);

  int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
  {
  	int err;

  	if (authsize > crypto_aead_maxauthsize(tfm))

  		return -EINVAL;

  	if (crypto_aead_alg(tfm)->setauthsize) {
  		err = crypto_aead_alg(tfm)->setauthsize(tfm, authsize);

  		if (err)
  			return err;
  	}

  	tfm->authsize = authsize;

  	return 0;
  }
  EXPORT_SYMBOL_GPL(crypto_aead_setauthsize);

  static void crypto_aead_exit_tfm(struct crypto_tfm *tfm)
  {
  	struct crypto_aead *aead = __crypto_aead_cast(tfm);
  	struct aead_alg *alg = crypto_aead_alg(aead);
  
  	alg->exit(aead);
  }

  static int crypto_aead_init_tfm(struct crypto_tfm *tfm)
  {
  	struct crypto_aead *aead = __crypto_aead_cast(tfm);
  	struct aead_alg *alg = crypto_aead_alg(aead);

  	aead->authsize = alg->maxauthsize;

  	if (alg->exit)
  		aead->base.exit = crypto_aead_exit_tfm;
  
  	if (alg->init)
  		return alg->init(aead);

  	return 0;
  }

  #ifdef CONFIG_NET

  static int crypto_aead_report(struct sk_buff *skb, struct crypto_alg *alg)
  {
  	struct crypto_report_aead raead;
  	struct aead_alg *aead = container_of(alg, struct aead_alg, base);
  
  	strncpy(raead.type, "aead", sizeof(raead.type));
  	strncpy(raead.geniv, "<none>", sizeof(raead.geniv));
  
  	raead.blocksize = alg->cra_blocksize;
  	raead.maxauthsize = aead->maxauthsize;
  	raead.ivsize = aead->ivsize;
  
  	if (nla_put(skb, CRYPTOCFGA_REPORT_AEAD,
  		    sizeof(struct crypto_report_aead), &raead))
  		goto nla_put_failure;
  	return 0;
  
  nla_put_failure:
  	return -EMSGSIZE;
  }
  #else
  static int crypto_aead_report(struct sk_buff *skb, struct crypto_alg *alg)
  {
  	return -ENOSYS;
  }
  #endif
  
  static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
  	__attribute__ ((unused));
  static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
  {
  	struct aead_alg *aead = container_of(alg, struct aead_alg, base);
  
  	seq_printf(m, "type         : aead
  ");
  	seq_printf(m, "async        : %s
  ", alg->cra_flags & CRYPTO_ALG_ASYNC ?
  					     "yes" : "no");
  	seq_printf(m, "blocksize    : %u
  ", alg->cra_blocksize);
  	seq_printf(m, "ivsize       : %u
  ", aead->ivsize);
  	seq_printf(m, "maxauthsize  : %u
  ", aead->maxauthsize);
  	seq_printf(m, "geniv        : <none>
  ");
  }

  static void crypto_aead_free_instance(struct crypto_instance *inst)
  {
  	struct aead_instance *aead = aead_instance(inst);
  
  	if (!aead->free) {
  		inst->tmpl->free(inst);
  		return;
  	}
  
  	aead->free(aead);
  }

  static const struct crypto_type crypto_aead_type = {

  	.extsize = crypto_alg_extsize,
  	.init_tfm = crypto_aead_init_tfm,

  	.free = crypto_aead_free_instance,

  #ifdef CONFIG_PROC_FS
  	.show = crypto_aead_show,
  #endif
  	.report = crypto_aead_report,
  	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
  	.maskset = CRYPTO_ALG_TYPE_MASK,
  	.type = CRYPTO_ALG_TYPE_AEAD,
  	.tfmsize = offsetof(struct crypto_aead, base),
  };

  static int aead_geniv_setkey(struct crypto_aead *tfm,
  			     const u8 *key, unsigned int keylen)
  {
  	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
  
  	return crypto_aead_setkey(ctx->child, key, keylen);
  }
  
  static int aead_geniv_setauthsize(struct crypto_aead *tfm,
  				  unsigned int authsize)
  {
  	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
  
  	return crypto_aead_setauthsize(ctx->child, authsize);
  }

  struct aead_instance *aead_geniv_alloc(struct crypto_template *tmpl,
  				       struct rtattr **tb, u32 type, u32 mask)

  {
  	const char *name;
  	struct crypto_aead_spawn *spawn;
  	struct crypto_attr_type *algt;

  	struct aead_instance *inst;
  	struct aead_alg *alg;
  	unsigned int ivsize;
  	unsigned int maxauthsize;

  	int err;
  
  	algt = crypto_get_attr_type(tb);

  	if (IS_ERR(algt))

  		return ERR_CAST(algt);

  	if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)

  		return ERR_PTR(-EINVAL);
  
  	name = crypto_attr_alg_name(tb[1]);

  	if (IS_ERR(name))

  		return ERR_CAST(name);

  
  	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
  	if (!inst)
  		return ERR_PTR(-ENOMEM);

  	spawn = aead_instance_ctx(inst);

  
  	/* Ignore async algorithms if necessary. */
  	mask |= crypto_requires_sync(algt->type, algt->mask);

  	crypto_set_aead_spawn(spawn, aead_crypto_instance(inst));

  	err = crypto_grab_aead(spawn, name, type, mask);

  	if (err)
  		goto err_free_inst;

  	alg = crypto_spawn_aead_alg(spawn);

  	ivsize = crypto_aead_alg_ivsize(alg);
  	maxauthsize = crypto_aead_alg_maxauthsize(alg);

  
  	err = -EINVAL;

  	if (ivsize < sizeof(u64))

  		goto err_drop_alg;

  	err = -ENAMETOOLONG;
  	if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
  		     "%s(%s)", tmpl->name, alg->base.cra_name) >=
  	    CRYPTO_MAX_ALG_NAME)
  		goto err_drop_alg;
  	if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
  		     "%s(%s)", tmpl->name, alg->base.cra_driver_name) >=
  	    CRYPTO_MAX_ALG_NAME)
  		goto err_drop_alg;

  	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;

  	inst->alg.base.cra_priority = alg->base.cra_priority;
  	inst->alg.base.cra_blocksize = alg->base.cra_blocksize;
  	inst->alg.base.cra_alignmask = alg->base.cra_alignmask;

  	inst->alg.base.cra_ctxsize = sizeof(struct aead_geniv_ctx);
  
  	inst->alg.setkey = aead_geniv_setkey;
  	inst->alg.setauthsize = aead_geniv_setauthsize;

  	inst->alg.ivsize = ivsize;
  	inst->alg.maxauthsize = maxauthsize;

  
  out:
  	return inst;
  
  err_drop_alg:
  	crypto_drop_aead(spawn);
  err_free_inst:
  	kfree(inst);
  	inst = ERR_PTR(err);
  	goto out;
  }
  EXPORT_SYMBOL_GPL(aead_geniv_alloc);

  void aead_geniv_free(struct aead_instance *inst)

  {

  	crypto_drop_aead(aead_instance_ctx(inst));

  	kfree(inst);
  }
  EXPORT_SYMBOL_GPL(aead_geniv_free);

  int aead_init_geniv(struct crypto_aead *aead)
  {
  	struct aead_geniv_ctx *ctx = crypto_aead_ctx(aead);
  	struct aead_instance *inst = aead_alg_instance(aead);
  	struct crypto_aead *child;
  	int err;
  
  	spin_lock_init(&ctx->lock);
  
  	err = crypto_get_default_rng();
  	if (err)
  		goto out;
  
  	err = crypto_rng_get_bytes(crypto_default_rng, ctx->salt,
  				   crypto_aead_ivsize(aead));
  	crypto_put_default_rng();
  	if (err)
  		goto out;

  	ctx->sknull = crypto_get_default_null_skcipher2();
  	err = PTR_ERR(ctx->sknull);
  	if (IS_ERR(ctx->sknull))
  		goto out;

  	child = crypto_spawn_aead(aead_instance_ctx(inst));
  	err = PTR_ERR(child);
  	if (IS_ERR(child))
  		goto drop_null;
  
  	ctx->child = child;
  	crypto_aead_set_reqsize(aead, crypto_aead_reqsize(child) +
  				      sizeof(struct aead_request));
  
  	err = 0;
  
  out:
  	return err;
  
  drop_null:

  	crypto_put_default_null_skcipher2();

  	goto out;
  }
  EXPORT_SYMBOL_GPL(aead_init_geniv);
  
  void aead_exit_geniv(struct crypto_aead *tfm)
  {
  	struct aead_geniv_ctx *ctx = crypto_aead_ctx(tfm);
  
  	crypto_free_aead(ctx->child);

  	crypto_put_default_null_skcipher2();

  }
  EXPORT_SYMBOL_GPL(aead_exit_geniv);

  int crypto_grab_aead(struct crypto_aead_spawn *spawn, const char *name,
  		     u32 type, u32 mask)
  {

  	spawn->base.frontend = &crypto_aead_type;
  	return crypto_grab_spawn(&spawn->base, name, type, mask);

  }
  EXPORT_SYMBOL_GPL(crypto_grab_aead);
  
  struct crypto_aead *crypto_alloc_aead(const char *alg_name, u32 type, u32 mask)
  {

  	return crypto_alloc_tfm(alg_name, &crypto_aead_type, type, mask);

  }
  EXPORT_SYMBOL_GPL(crypto_alloc_aead);

  static int aead_prepare_alg(struct aead_alg *alg)
  {
  	struct crypto_alg *base = &alg->base;

  	if (max3(alg->maxauthsize, alg->ivsize, alg->chunksize) >
  	    PAGE_SIZE / 8)

  		return -EINVAL;

  	if (!alg->chunksize)
  		alg->chunksize = base->cra_blocksize;

  	base->cra_type = &crypto_aead_type;

  	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
  	base->cra_flags |= CRYPTO_ALG_TYPE_AEAD;
  
  	return 0;
  }
  
  int crypto_register_aead(struct aead_alg *alg)
  {
  	struct crypto_alg *base = &alg->base;
  	int err;
  
  	err = aead_prepare_alg(alg);
  	if (err)
  		return err;
  
  	return crypto_register_alg(base);
  }
  EXPORT_SYMBOL_GPL(crypto_register_aead);

  void crypto_unregister_aead(struct aead_alg *alg)

  {

  	crypto_unregister_alg(&alg->base);

  }
  EXPORT_SYMBOL_GPL(crypto_unregister_aead);

  int crypto_register_aeads(struct aead_alg *algs, int count)
  {
  	int i, ret;
  
  	for (i = 0; i < count; i++) {
  		ret = crypto_register_aead(&algs[i]);
  		if (ret)
  			goto err;
  	}
  
  	return 0;
  
  err:
  	for (--i; i >= 0; --i)
  		crypto_unregister_aead(&algs[i]);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(crypto_register_aeads);
  
  void crypto_unregister_aeads(struct aead_alg *algs, int count)
  {
  	int i;
  
  	for (i = count - 1; i >= 0; --i)
  		crypto_unregister_aead(&algs[i]);
  }
  EXPORT_SYMBOL_GPL(crypto_unregister_aeads);

  int aead_register_instance(struct crypto_template *tmpl,
  			   struct aead_instance *inst)
  {
  	int err;
  
  	err = aead_prepare_alg(&inst->alg);
  	if (err)
  		return err;
  
  	return crypto_register_instance(tmpl, aead_crypto_instance(inst));
  }
  EXPORT_SYMBOL_GPL(aead_register_instance);

  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Authenticated Encryption with Associated Data (AEAD)");