/*
   * Asynchronous block chaining cipher operations.
   * 
   * This is the asynchronous version of blkcipher.c indicating completion
   * via a callback.
   *
   * Copyright (c) 2006 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/err.h>

  #include <linux/init.h>

  #include <linux/kernel.h>

  #include <linux/module.h>

  #include <linux/rtnetlink.h>
  #include <linux/sched.h>

  #include <linux/slab.h>

  #include <linux/seq_file.h>

  #include "internal.h"

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

  {
  	struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);
  	unsigned long alignmask = crypto_ablkcipher_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 = cipher->setkey(tfm, alignbuffer, keylen);

  	memset(alignbuffer, 0, keylen);

  	kfree(buffer);
  	return ret;
  }

  static int setkey(struct crypto_ablkcipher *tfm, const u8 *key,
  		  unsigned int keylen)
  {
  	struct ablkcipher_alg *cipher = crypto_ablkcipher_alg(tfm);

  	unsigned long alignmask = crypto_ablkcipher_alignmask(tfm);

  
  	if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) {
  		crypto_ablkcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
  		return -EINVAL;
  	}

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

  	return cipher->setkey(tfm, key, keylen);
  }
  
  static unsigned int crypto_ablkcipher_ctxsize(struct crypto_alg *alg, u32 type,
  					      u32 mask)
  {
  	return alg->cra_ctxsize;
  }

  int skcipher_null_givencrypt(struct skcipher_givcrypt_request *req)
  {
  	return crypto_ablkcipher_encrypt(&req->creq);
  }
  
  int skcipher_null_givdecrypt(struct skcipher_givcrypt_request *req)
  {
  	return crypto_ablkcipher_decrypt(&req->creq);
  }

  static int crypto_init_ablkcipher_ops(struct crypto_tfm *tfm, u32 type,
  				      u32 mask)
  {
  	struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
  	struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
  
  	if (alg->ivsize > PAGE_SIZE / 8)
  		return -EINVAL;
  
  	crt->setkey = setkey;
  	crt->encrypt = alg->encrypt;
  	crt->decrypt = alg->decrypt;

  	if (!alg->ivsize) {
  		crt->givencrypt = skcipher_null_givencrypt;
  		crt->givdecrypt = skcipher_null_givdecrypt;
  	}

  	crt->base = __crypto_ablkcipher_cast(tfm);

  	crt->ivsize = alg->ivsize;
  
  	return 0;
  }
  
  static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
  	__attribute__ ((unused));
  static void crypto_ablkcipher_show(struct seq_file *m, struct crypto_alg *alg)
  {
  	struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
  
  	seq_printf(m, "type         : ablkcipher
  ");

  	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
  ", ablkcipher->min_keysize);
  	seq_printf(m, "max keysize  : %u
  ", ablkcipher->max_keysize);
  	seq_printf(m, "ivsize       : %u
  ", ablkcipher->ivsize);

  	seq_printf(m, "geniv        : %s
  ", ablkcipher->geniv ?: "<default>");

  }
  
  const struct crypto_type crypto_ablkcipher_type = {
  	.ctxsize = crypto_ablkcipher_ctxsize,
  	.init = crypto_init_ablkcipher_ops,
  #ifdef CONFIG_PROC_FS
  	.show = crypto_ablkcipher_show,
  #endif
  };
  EXPORT_SYMBOL_GPL(crypto_ablkcipher_type);

  static int no_givdecrypt(struct skcipher_givcrypt_request *req)
  {
  	return -ENOSYS;
  }
  
  static int crypto_init_givcipher_ops(struct crypto_tfm *tfm, u32 type,
  				      u32 mask)
  {
  	struct ablkcipher_alg *alg = &tfm->__crt_alg->cra_ablkcipher;
  	struct ablkcipher_tfm *crt = &tfm->crt_ablkcipher;
  
  	if (alg->ivsize > PAGE_SIZE / 8)
  		return -EINVAL;

  	crt->setkey = tfm->__crt_alg->cra_flags & CRYPTO_ALG_GENIV ?
  		      alg->setkey : setkey;

  	crt->encrypt = alg->encrypt;
  	crt->decrypt = alg->decrypt;
  	crt->givencrypt = alg->givencrypt;
  	crt->givdecrypt = alg->givdecrypt ?: no_givdecrypt;

  	crt->base = __crypto_ablkcipher_cast(tfm);

  	crt->ivsize = alg->ivsize;
  
  	return 0;
  }
  
  static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
  	__attribute__ ((unused));
  static void crypto_givcipher_show(struct seq_file *m, struct crypto_alg *alg)
  {
  	struct ablkcipher_alg *ablkcipher = &alg->cra_ablkcipher;
  
  	seq_printf(m, "type         : givcipher
  ");

  	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
  ", ablkcipher->min_keysize);
  	seq_printf(m, "max keysize  : %u
  ", ablkcipher->max_keysize);
  	seq_printf(m, "ivsize       : %u
  ", ablkcipher->ivsize);

  	seq_printf(m, "geniv        : %s
  ", ablkcipher->geniv ?: "<built-in>");

  }
  
  const struct crypto_type crypto_givcipher_type = {
  	.ctxsize = crypto_ablkcipher_ctxsize,
  	.init = crypto_init_givcipher_ops,
  #ifdef CONFIG_PROC_FS
  	.show = crypto_givcipher_show,
  #endif
  };
  EXPORT_SYMBOL_GPL(crypto_givcipher_type);

  const char *crypto_default_geniv(const struct crypto_alg *alg)
  {
  	return alg->cra_flags & CRYPTO_ALG_ASYNC ? "eseqiv" : "chainiv";
  }

  static int crypto_givcipher_default(struct crypto_alg *alg, u32 type, u32 mask)
  {
  	struct rtattr *tb[3];
  	struct {
  		struct rtattr attr;
  		struct crypto_attr_type data;
  	} ptype;
  	struct {
  		struct rtattr attr;
  		struct crypto_attr_alg data;
  	} palg;
  	struct crypto_template *tmpl;
  	struct crypto_instance *inst;
  	struct crypto_alg *larval;
  	const char *geniv;
  	int err;
  
  	larval = crypto_larval_lookup(alg->cra_driver_name,
  				      CRYPTO_ALG_TYPE_GIVCIPHER,
  				      CRYPTO_ALG_TYPE_MASK);
  	err = PTR_ERR(larval);
  	if (IS_ERR(larval))
  		goto out;
  
  	err = -EAGAIN;
  	if (!crypto_is_larval(larval))
  		goto drop_larval;
  
  	ptype.attr.rta_len = sizeof(ptype);
  	ptype.attr.rta_type = CRYPTOA_TYPE;
  	ptype.data.type = type | CRYPTO_ALG_GENIV;
  	/* GENIV tells the template that we're making a default geniv. */
  	ptype.data.mask = mask | CRYPTO_ALG_GENIV;
  	tb[0] = &ptype.attr;
  
  	palg.attr.rta_len = sizeof(palg);
  	palg.attr.rta_type = CRYPTOA_ALG;
  	/* Must use the exact name to locate ourselves. */
  	memcpy(palg.data.name, alg->cra_driver_name, CRYPTO_MAX_ALG_NAME);
  	tb[1] = &palg.attr;
  
  	tb[2] = NULL;
  
  	if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
  	    CRYPTO_ALG_TYPE_BLKCIPHER)
  		geniv = alg->cra_blkcipher.geniv;
  	else
  		geniv = alg->cra_ablkcipher.geniv;
  
  	if (!geniv)
  		geniv = crypto_default_geniv(alg);
  
  	tmpl = crypto_lookup_template(geniv);
  	err = -ENOENT;
  	if (!tmpl)
  		goto kill_larval;
  
  	inst = tmpl->alloc(tb);
  	err = PTR_ERR(inst);
  	if (IS_ERR(inst))
  		goto put_tmpl;
  
  	if ((err = crypto_register_instance(tmpl, inst))) {
  		tmpl->free(inst);
  		goto put_tmpl;
  	}
  
  	/* Redo the lookup to use the instance we just registered. */
  	err = -EAGAIN;
  
  put_tmpl:
  	crypto_tmpl_put(tmpl);
  kill_larval:
  	crypto_larval_kill(larval);
  drop_larval:
  	crypto_mod_put(larval);
  out:
  	crypto_mod_put(alg);
  	return err;
  }
  
  static struct crypto_alg *crypto_lookup_skcipher(const char *name, u32 type,
  						 u32 mask)
  {
  	struct crypto_alg *alg;
  
  	alg = crypto_alg_mod_lookup(name, type, mask);
  	if (IS_ERR(alg))
  		return alg;
  
  	if ((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
  	    CRYPTO_ALG_TYPE_GIVCIPHER)
  		return alg;
  
  	if (!((alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
  	      CRYPTO_ALG_TYPE_BLKCIPHER ? alg->cra_blkcipher.ivsize :
  					  alg->cra_ablkcipher.ivsize))
  		return alg;
  
  	return ERR_PTR(crypto_givcipher_default(alg, type, mask));
  }

  int crypto_grab_skcipher(struct crypto_skcipher_spawn *spawn, const char *name,
  			 u32 type, u32 mask)
  {
  	struct crypto_alg *alg;
  	int err;
  
  	type = crypto_skcipher_type(type);
  	mask = crypto_skcipher_mask(mask);

  	alg = crypto_lookup_skcipher(name, type, mask);

  	if (IS_ERR(alg))
  		return PTR_ERR(alg);
  
  	err = crypto_init_spawn(&spawn->base, alg, spawn->base.inst, mask);
  	crypto_mod_put(alg);
  	return err;
  }
  EXPORT_SYMBOL_GPL(crypto_grab_skcipher);

  struct crypto_ablkcipher *crypto_alloc_ablkcipher(const char *alg_name,
  						  u32 type, u32 mask)
  {
  	struct crypto_tfm *tfm;
  	int err;
  
  	type = crypto_skcipher_type(type);
  	mask = crypto_skcipher_mask(mask);
  
  	for (;;) {
  		struct crypto_alg *alg;
  
  		alg = crypto_lookup_skcipher(alg_name, type, mask);
  		if (IS_ERR(alg)) {
  			err = PTR_ERR(alg);
  			goto err;
  		}
  
  		tfm = __crypto_alloc_tfm(alg, type, mask);
  		if (!IS_ERR(tfm))
  			return __crypto_ablkcipher_cast(tfm);
  
  		crypto_mod_put(alg);
  		err = PTR_ERR(tfm);
  
  err:
  		if (err != -EAGAIN)
  			break;
  		if (signal_pending(current)) {
  			err = -EINTR;
  			break;
  		}
  	}
  
  	return ERR_PTR(err);
  }
  EXPORT_SYMBOL_GPL(crypto_alloc_ablkcipher);