/*
   * Synchronous Cryptographic Hash operations.
   *
   * Copyright (c) 2008 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/scatterwalk.h>

  #include <crypto/internal/hash.h>
  #include <linux/err.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/seq_file.h>

  #include "internal.h"

  static const struct crypto_type crypto_shash_type;

  static int shash_setkey_unaligned(struct crypto_shash *tfm, const u8 *key,
  				  unsigned int keylen)
  {
  	struct shash_alg *shash = crypto_shash_alg(tfm);
  	unsigned long alignmask = crypto_shash_alignmask(tfm);
  	unsigned long absize;
  	u8 *buffer, *alignbuffer;
  	int err;
  
  	absize = keylen + (alignmask & ~(CRYPTO_MINALIGN - 1));
  	buffer = kmalloc(absize, GFP_KERNEL);
  	if (!buffer)
  		return -ENOMEM;
  
  	alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  	memcpy(alignbuffer, key, keylen);
  	err = shash->setkey(tfm, alignbuffer, keylen);
  	memset(alignbuffer, 0, keylen);
  	kfree(buffer);
  	return err;
  }
  
  int crypto_shash_setkey(struct crypto_shash *tfm, const u8 *key,
  			unsigned int keylen)
  {
  	struct shash_alg *shash = crypto_shash_alg(tfm);
  	unsigned long alignmask = crypto_shash_alignmask(tfm);

  	if (!shash->setkey)
  		return -ENOSYS;

  	if ((unsigned long)key & alignmask)
  		return shash_setkey_unaligned(tfm, key, keylen);
  
  	return shash->setkey(tfm, key, keylen);
  }
  EXPORT_SYMBOL_GPL(crypto_shash_setkey);
  
  static inline unsigned int shash_align_buffer_size(unsigned len,
  						   unsigned long mask)
  {
  	return len + (mask & ~(__alignof__(u8 __attribute__ ((aligned))) - 1));
  }
  
  static int shash_update_unaligned(struct shash_desc *desc, const u8 *data,
  				  unsigned int len)
  {
  	struct crypto_shash *tfm = desc->tfm;
  	struct shash_alg *shash = crypto_shash_alg(tfm);
  	unsigned long alignmask = crypto_shash_alignmask(tfm);
  	unsigned int unaligned_len = alignmask + 1 -
  				     ((unsigned long)data & alignmask);
  	u8 buf[shash_align_buffer_size(unaligned_len, alignmask)]
  		__attribute__ ((aligned));
  
  	memcpy(buf, data, unaligned_len);
  
  	return shash->update(desc, buf, unaligned_len) ?:
  	       shash->update(desc, data + unaligned_len, len - unaligned_len);
  }
  
  int crypto_shash_update(struct shash_desc *desc, const u8 *data,
  			unsigned int len)
  {
  	struct crypto_shash *tfm = desc->tfm;
  	struct shash_alg *shash = crypto_shash_alg(tfm);
  	unsigned long alignmask = crypto_shash_alignmask(tfm);
  
  	if ((unsigned long)data & alignmask)
  		return shash_update_unaligned(desc, data, len);
  
  	return shash->update(desc, data, len);
  }
  EXPORT_SYMBOL_GPL(crypto_shash_update);
  
  static int shash_final_unaligned(struct shash_desc *desc, u8 *out)
  {
  	struct crypto_shash *tfm = desc->tfm;
  	unsigned long alignmask = crypto_shash_alignmask(tfm);
  	struct shash_alg *shash = crypto_shash_alg(tfm);
  	unsigned int ds = crypto_shash_digestsize(tfm);
  	u8 buf[shash_align_buffer_size(ds, alignmask)]
  		__attribute__ ((aligned));
  	int err;
  
  	err = shash->final(desc, buf);
  	memcpy(out, buf, ds);
  	return err;
  }
  
  int crypto_shash_final(struct shash_desc *desc, u8 *out)
  {
  	struct crypto_shash *tfm = desc->tfm;
  	struct shash_alg *shash = crypto_shash_alg(tfm);
  	unsigned long alignmask = crypto_shash_alignmask(tfm);
  
  	if ((unsigned long)out & alignmask)
  		return shash_final_unaligned(desc, out);
  
  	return shash->final(desc, out);
  }
  EXPORT_SYMBOL_GPL(crypto_shash_final);
  
  static int shash_finup_unaligned(struct shash_desc *desc, const u8 *data,
  				 unsigned int len, u8 *out)
  {
  	return crypto_shash_update(desc, data, len) ?:
  	       crypto_shash_final(desc, out);
  }
  
  int crypto_shash_finup(struct shash_desc *desc, const u8 *data,
  		       unsigned int len, u8 *out)
  {
  	struct crypto_shash *tfm = desc->tfm;
  	struct shash_alg *shash = crypto_shash_alg(tfm);
  	unsigned long alignmask = crypto_shash_alignmask(tfm);
  
  	if (((unsigned long)data | (unsigned long)out) & alignmask ||
  	    !shash->finup)
  		return shash_finup_unaligned(desc, data, len, out);
  
  	return shash->finup(desc, data, len, out);
  }
  EXPORT_SYMBOL_GPL(crypto_shash_finup);
  
  static int shash_digest_unaligned(struct shash_desc *desc, const u8 *data,
  				  unsigned int len, u8 *out)
  {
  	return crypto_shash_init(desc) ?:
  	       crypto_shash_update(desc, data, len) ?:
  	       crypto_shash_final(desc, out);
  }
  
  int crypto_shash_digest(struct shash_desc *desc, const u8 *data,
  			unsigned int len, u8 *out)
  {
  	struct crypto_shash *tfm = desc->tfm;
  	struct shash_alg *shash = crypto_shash_alg(tfm);
  	unsigned long alignmask = crypto_shash_alignmask(tfm);
  
  	if (((unsigned long)data | (unsigned long)out) & alignmask ||
  	    !shash->digest)
  		return shash_digest_unaligned(desc, data, len, out);
  
  	return shash->digest(desc, data, len, out);
  }
  EXPORT_SYMBOL_GPL(crypto_shash_digest);

  int crypto_shash_import(struct shash_desc *desc, const u8 *in)
  {
  	struct crypto_shash *tfm = desc->tfm;
  	struct shash_alg *alg = crypto_shash_alg(tfm);
  
  	memcpy(shash_desc_ctx(desc), in, crypto_shash_descsize(tfm));
  
  	if (alg->reinit)
  		alg->reinit(desc);
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(crypto_shash_import);

  static int shash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
  			      unsigned int keylen)
  {
  	struct crypto_shash **ctx = crypto_ahash_ctx(tfm);
  
  	return crypto_shash_setkey(*ctx, key, keylen);
  }
  
  static int shash_async_init(struct ahash_request *req)
  {
  	struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
  	struct shash_desc *desc = ahash_request_ctx(req);
  
  	desc->tfm = *ctx;
  	desc->flags = req->base.flags;
  
  	return crypto_shash_init(desc);
  }
  
  static int shash_async_update(struct ahash_request *req)
  {
  	struct shash_desc *desc = ahash_request_ctx(req);
  	struct crypto_hash_walk walk;
  	int nbytes;
  
  	for (nbytes = crypto_hash_walk_first(req, &walk); nbytes > 0;
  	     nbytes = crypto_hash_walk_done(&walk, nbytes))
  		nbytes = crypto_shash_update(desc, walk.data, nbytes);
  
  	return nbytes;
  }
  
  static int shash_async_final(struct ahash_request *req)
  {
  	return crypto_shash_final(ahash_request_ctx(req), req->result);
  }
  
  static int shash_async_digest(struct ahash_request *req)
  {
  	struct scatterlist *sg = req->src;
  	unsigned int offset = sg->offset;
  	unsigned int nbytes = req->nbytes;
  	int err;
  
  	if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
  		struct crypto_shash **ctx =
  			crypto_ahash_ctx(crypto_ahash_reqtfm(req));
  		struct shash_desc *desc = ahash_request_ctx(req);
  		void *data;
  
  		desc->tfm = *ctx;
  		desc->flags = req->base.flags;
  
  		data = crypto_kmap(sg_page(sg), 0);
  		err = crypto_shash_digest(desc, data + offset, nbytes,
  					  req->result);
  		crypto_kunmap(data, 0);
  		crypto_yield(desc->flags);
  		goto out;
  	}
  
  	err = shash_async_init(req);
  	if (err)
  		goto out;
  
  	err = shash_async_update(req);
  	if (err)
  		goto out;
  
  	err = shash_async_final(req);
  
  out:
  	return err;
  }
  
  static void crypto_exit_shash_ops_async(struct crypto_tfm *tfm)
  {
  	struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
  
  	crypto_free_shash(*ctx);
  }
  
  static int crypto_init_shash_ops_async(struct crypto_tfm *tfm)
  {
  	struct crypto_alg *calg = tfm->__crt_alg;
  	struct shash_alg *alg = __crypto_shash_alg(calg);
  	struct ahash_tfm *crt = &tfm->crt_ahash;
  	struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
  	struct crypto_shash *shash;
  
  	if (!crypto_mod_get(calg))
  		return -EAGAIN;

  	shash = crypto_create_tfm(calg, &crypto_shash_type);

  	if (IS_ERR(shash)) {
  		crypto_mod_put(calg);
  		return PTR_ERR(shash);
  	}
  
  	*ctx = shash;
  	tfm->exit = crypto_exit_shash_ops_async;
  
  	crt->init = shash_async_init;
  	crt->update = shash_async_update;
  	crt->final  = shash_async_final;
  	crt->digest = shash_async_digest;
  	crt->setkey = shash_async_setkey;
  
  	crt->digestsize = alg->digestsize;
  	crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);
  
  	return 0;
  }

  static int shash_compat_setkey(struct crypto_hash *tfm, const u8 *key,
  			       unsigned int keylen)
  {
  	struct shash_desc *desc = crypto_hash_ctx(tfm);
  
  	return crypto_shash_setkey(desc->tfm, key, keylen);
  }
  
  static int shash_compat_init(struct hash_desc *hdesc)
  {
  	struct shash_desc *desc = crypto_hash_ctx(hdesc->tfm);
  
  	desc->flags = hdesc->flags;
  
  	return crypto_shash_init(desc);
  }
  
  static int shash_compat_update(struct hash_desc *hdesc, struct scatterlist *sg,
  			       unsigned int len)
  {
  	struct shash_desc *desc = crypto_hash_ctx(hdesc->tfm);
  	struct crypto_hash_walk walk;
  	int nbytes;
  
  	for (nbytes = crypto_hash_walk_first_compat(hdesc, &walk, sg, len);
  	     nbytes > 0; nbytes = crypto_hash_walk_done(&walk, nbytes))
  		nbytes = crypto_shash_update(desc, walk.data, nbytes);
  
  	return nbytes;
  }
  
  static int shash_compat_final(struct hash_desc *hdesc, u8 *out)
  {
  	return crypto_shash_final(crypto_hash_ctx(hdesc->tfm), out);
  }
  
  static int shash_compat_digest(struct hash_desc *hdesc, struct scatterlist *sg,
  			       unsigned int nbytes, u8 *out)
  {
  	unsigned int offset = sg->offset;
  	int err;
  
  	if (nbytes < min(sg->length, ((unsigned int)(PAGE_SIZE)) - offset)) {
  		struct shash_desc *desc = crypto_hash_ctx(hdesc->tfm);
  		void *data;
  
  		desc->flags = hdesc->flags;
  
  		data = crypto_kmap(sg_page(sg), 0);
  		err = crypto_shash_digest(desc, data + offset, nbytes, out);
  		crypto_kunmap(data, 0);
  		crypto_yield(desc->flags);
  		goto out;
  	}
  
  	err = shash_compat_init(hdesc);
  	if (err)
  		goto out;
  
  	err = shash_compat_update(hdesc, sg, nbytes);
  	if (err)
  		goto out;
  
  	err = shash_compat_final(hdesc, out);
  
  out:
  	return err;
  }
  
  static void crypto_exit_shash_ops_compat(struct crypto_tfm *tfm)
  {
  	struct shash_desc *desc= crypto_tfm_ctx(tfm);
  
  	crypto_free_shash(desc->tfm);
  }
  
  static int crypto_init_shash_ops_compat(struct crypto_tfm *tfm)
  {
  	struct hash_tfm *crt = &tfm->crt_hash;
  	struct crypto_alg *calg = tfm->__crt_alg;
  	struct shash_alg *alg = __crypto_shash_alg(calg);
  	struct shash_desc *desc = crypto_tfm_ctx(tfm);
  	struct crypto_shash *shash;

  	if (!crypto_mod_get(calg))
  		return -EAGAIN;

  	shash = crypto_create_tfm(calg, &crypto_shash_type);

  	if (IS_ERR(shash)) {
  		crypto_mod_put(calg);

  		return PTR_ERR(shash);

  	}

  
  	desc->tfm = shash;
  	tfm->exit = crypto_exit_shash_ops_compat;
  
  	crt->init = shash_compat_init;
  	crt->update = shash_compat_update;
  	crt->final  = shash_compat_final;
  	crt->digest = shash_compat_digest;
  	crt->setkey = shash_compat_setkey;
  
  	crt->digestsize = alg->digestsize;
  
  	return 0;
  }

  static int crypto_init_shash_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
  {
  	switch (mask & CRYPTO_ALG_TYPE_MASK) {

  	case CRYPTO_ALG_TYPE_HASH_MASK:
  		return crypto_init_shash_ops_compat(tfm);

  	case CRYPTO_ALG_TYPE_AHASH_MASK:
  		return crypto_init_shash_ops_async(tfm);
  	}
  
  	return -EINVAL;
  }
  
  static unsigned int crypto_shash_ctxsize(struct crypto_alg *alg, u32 type,
  					 u32 mask)
  {

  	struct shash_alg *salg = __crypto_shash_alg(alg);

  	switch (mask & CRYPTO_ALG_TYPE_MASK) {

  	case CRYPTO_ALG_TYPE_HASH_MASK:
  		return sizeof(struct shash_desc) + salg->descsize;

  	case CRYPTO_ALG_TYPE_AHASH_MASK:
  		return sizeof(struct crypto_shash *);
  	}
  
  	return 0;
  }

  static int crypto_shash_init_tfm(struct crypto_tfm *tfm,
  				 const struct crypto_type *frontend)
  {

  	return 0;
  }
  
  static unsigned int crypto_shash_extsize(struct crypto_alg *alg,
  					 const struct crypto_type *frontend)
  {
  	return alg->cra_ctxsize;
  }
  
  static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
  	__attribute__ ((unused));
  static void crypto_shash_show(struct seq_file *m, struct crypto_alg *alg)
  {
  	struct shash_alg *salg = __crypto_shash_alg(alg);
  
  	seq_printf(m, "type         : shash
  ");
  	seq_printf(m, "blocksize    : %u
  ", alg->cra_blocksize);
  	seq_printf(m, "digestsize   : %u
  ", salg->digestsize);
  	seq_printf(m, "descsize     : %u
  ", salg->descsize);
  }
  
  static const struct crypto_type crypto_shash_type = {

  	.ctxsize = crypto_shash_ctxsize,

  	.extsize = crypto_shash_extsize,

  	.init = crypto_init_shash_ops,

  	.init_tfm = crypto_shash_init_tfm,
  #ifdef CONFIG_PROC_FS
  	.show = crypto_shash_show,
  #endif
  	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
  	.maskset = CRYPTO_ALG_TYPE_MASK,
  	.type = CRYPTO_ALG_TYPE_SHASH,
  	.tfmsize = offsetof(struct crypto_shash, base),
  };
  
  struct crypto_shash *crypto_alloc_shash(const char *alg_name, u32 type,
  					u32 mask)
  {

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

  }
  EXPORT_SYMBOL_GPL(crypto_alloc_shash);
  
  int crypto_register_shash(struct shash_alg *alg)
  {
  	struct crypto_alg *base = &alg->base;
  
  	if (alg->digestsize > PAGE_SIZE / 8 ||
  	    alg->descsize > PAGE_SIZE / 8)
  		return -EINVAL;
  
  	base->cra_type = &crypto_shash_type;
  	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
  	base->cra_flags |= CRYPTO_ALG_TYPE_SHASH;
  
  	return crypto_register_alg(base);
  }
  EXPORT_SYMBOL_GPL(crypto_register_shash);
  
  int crypto_unregister_shash(struct shash_alg *alg)
  {
  	return crypto_unregister_alg(&alg->base);
  }
  EXPORT_SYMBOL_GPL(crypto_unregister_shash);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Synchronous cryptographic hash type");