crypto/ahash.c - kernel/msm-4.9 - Gitiles

 /*
  * Asynchronous Cryptographic Hash operations.
  *
  * This is the asynchronous version of hash.c with notification of
  * completion via a callback.
  *
  * Copyright (c) 2008 Loc Ho <lho@amcc.com>
  *
  * 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/hash.h>
 #include <crypto/scatterwalk.h>
 #include <linux/bug.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/seq_file.h>
 #include <linux/cryptouser.h>
 #include <net/netlink.h>

 #include "internal.h"

 struct ahash_request_priv {
 	crypto_completion_t complete;
 	void *data;
 	u8 *result;
 	u32 flags;
 	void *ubuf[] CRYPTO_MINALIGN_ATTR;
 };

 static inline struct ahash_alg *crypto_ahash_alg(struct crypto_ahash *hash)
 {
 	return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
 			    halg);
 }

 static int hash_walk_next(struct crypto_hash_walk *walk)
 {
 	unsigned int alignmask = walk->alignmask;
 	unsigned int offset = walk->offset;
 	unsigned int nbytes = min(walk->entrylen,
 				  ((unsigned int)(PAGE_SIZE)) - offset);

 	if (walk->flags & CRYPTO_ALG_ASYNC)
 		walk->data = kmap(walk->pg);
 	else
 		walk->data = kmap_atomic(walk->pg);
 	walk->data += offset;

 	if (offset & alignmask) {
 		unsigned int unaligned = alignmask + 1 - (offset & alignmask);

 		if (nbytes > unaligned)
 			nbytes = unaligned;
 	}

 	walk->entrylen -= nbytes;
 	return nbytes;
 }

 static int hash_walk_new_entry(struct crypto_hash_walk *walk)
 {
 	struct scatterlist *sg;

 	sg = walk->sg;
 	walk->offset = sg->offset;
 	walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
 	walk->offset = offset_in_page(walk->offset);
 	walk->entrylen = sg->length;

 	if (walk->entrylen > walk->total)
 		walk->entrylen = walk->total;
 	walk->total -= walk->entrylen;

 	return hash_walk_next(walk);
 }

 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
 {
 	unsigned int alignmask = walk->alignmask;
 	unsigned int nbytes = walk->entrylen;

 	walk->data -= walk->offset;

 	if (nbytes && walk->offset & alignmask && !err) {
 		walk->offset = ALIGN(walk->offset, alignmask + 1);
 		nbytes = min(nbytes,
 			     ((unsigned int)(PAGE_SIZE)) - walk->offset);
 		walk->entrylen -= nbytes;

 		if (nbytes) {
 			walk->data += walk->offset;
 			return nbytes;
 		}
 	}

 	if (walk->flags & CRYPTO_ALG_ASYNC)
 		kunmap(walk->pg);
 	else {
 		kunmap_atomic(walk->data);
 		/*
 		 * The may sleep test only makes sense for sync users.
 		 * Async users don't need to sleep here anyway.
 		 */
 		crypto_yield(walk->flags);
 	}

 	if (err)
 		return err;

 	if (nbytes) {
 		walk->offset = 0;
 		walk->pg++;
 		return hash_walk_next(walk);
 	}

 	if (!walk->total)
 		return 0;

 	walk->sg = sg_next(walk->sg);

 	return hash_walk_new_entry(walk);
 }
 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);

 int crypto_hash_walk_first(struct ahash_request *req,
 			   struct crypto_hash_walk *walk)
 {
 	walk->total = req->nbytes;

 	if (!walk->total) {
 		walk->entrylen = 0;
 		return 0;
 	}

 	walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 	walk->sg = req->src;
 	walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;

 	return hash_walk_new_entry(walk);
 }
 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);

 int crypto_ahash_walk_first(struct ahash_request *req,
 			    struct crypto_hash_walk *walk)
 {
 	walk->total = req->nbytes;

 	if (!walk->total) {
 		walk->entrylen = 0;
 		return 0;
 	}

 	walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
 	walk->sg = req->src;
 	walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
 	walk->flags |= CRYPTO_ALG_ASYNC;

 	BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC);

 	return hash_walk_new_entry(walk);
 }
 EXPORT_SYMBOL_GPL(crypto_ahash_walk_first);

 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 				unsigned int keylen)
 {
 	unsigned long alignmask = crypto_ahash_alignmask(tfm);
 	int ret;
 	u8 *buffer, *alignbuffer;
 	unsigned long absize;

 	absize = keylen + alignmask;
 	buffer = kmalloc(absize, GFP_KERNEL);
 	if (!buffer)
 		return -ENOMEM;

 	alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 	memcpy(alignbuffer, key, keylen);
 	ret = tfm->setkey(tfm, alignbuffer, keylen);
 	kzfree(buffer);
 	return ret;
 }

 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 			unsigned int keylen)
 {
 	unsigned long alignmask = crypto_ahash_alignmask(tfm);
 	int err;

 	if ((unsigned long)key & alignmask)
 		err = ahash_setkey_unaligned(tfm, key, keylen);
 	else
 		err = tfm->setkey(tfm, key, keylen);

 	if (err)
 		return err;

 	crypto_ahash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);

 static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 			  unsigned int keylen)
 {
 	return -ENOSYS;
 }

 static inline unsigned int ahash_align_buffer_size(unsigned len,
 						   unsigned long mask)
 {
 	return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
 }

 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
 {
 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 	unsigned long alignmask = crypto_ahash_alignmask(tfm);
 	unsigned int ds = crypto_ahash_digestsize(tfm);
 	struct ahash_request_priv *priv;

 	priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
 		       (req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
 		       GFP_KERNEL : GFP_ATOMIC);
 	if (!priv)
 		return -ENOMEM;

 	/*
 	 * WARNING: Voodoo programming below!
 	 *
 	 * The code below is obscure and hard to understand, thus explanation
 	 * is necessary. See include/crypto/hash.h and include/linux/crypto.h
 	 * to understand the layout of structures used here!
 	 *
 	 * The code here will replace portions of the ORIGINAL request with
 	 * pointers to new code and buffers so the hashing operation can store
 	 * the result in aligned buffer. We will call the modified request
 	 * an ADJUSTED request.
 	 *
 	 * The newly mangled request will look as such:
 	 *
 	 * req {
 	 *   .result        = ADJUSTED[new aligned buffer]
 	 *   .base.complete = ADJUSTED[pointer to completion function]
 	 *   .base.data     = ADJUSTED[*req (pointer to self)]
 	 *   .priv          = ADJUSTED[new priv] {
 	 *           .result   = ORIGINAL(result)
 	 *           .complete = ORIGINAL(base.complete)
 	 *           .data     = ORIGINAL(base.data)
 	 *   }
 	 */

 	priv->result = req->result;
 	priv->complete = req->base.complete;
 	priv->data = req->base.data;
 	priv->flags = req->base.flags;

 	/*
 	 * WARNING: We do not backup req->priv here! The req->priv
 	 *          is for internal use of the Crypto API and the
 	 *          user must _NOT_ _EVER_ depend on it's content!
 	 */

 	req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
 	req->base.complete = cplt;
 	req->base.data = req;
 	req->priv = priv;

 	return 0;
 }

 static void ahash_restore_req(struct ahash_request *req, int err)
 {
 	struct ahash_request_priv *priv = req->priv;

 	if (!err)
 		memcpy(priv->result, req->result,
 		       crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));

 	/* Restore the original crypto request. */
 	req->result = priv->result;

 	ahash_request_set_callback(req, priv->flags,
 				   priv->complete, priv->data);
 	req->priv = NULL;

 	/* Free the req->priv.priv from the ADJUSTED request. */
 	kzfree(priv);
 }

 static void ahash_notify_einprogress(struct ahash_request *req)
 {
 	struct ahash_request_priv *priv = req->priv;
 	struct crypto_async_request oreq;

 	oreq.data = priv->data;

 	priv->complete(&oreq, -EINPROGRESS);
 }

 static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
 {
 	struct ahash_request *areq = req->data;

 	if (err == -EINPROGRESS) {
 		ahash_notify_einprogress(areq);
 		return;
 	}

 	/*
 	 * Restore the original request, see ahash_op_unaligned() for what
 	 * goes where.
 	 *
 	 * The "struct ahash_request *req" here is in fact the "req.base"
 	 * from the ADJUSTED request from ahash_op_unaligned(), thus as it
 	 * is a pointer to self, it is also the ADJUSTED "req" .
 	 */

 	/* First copy req->result into req->priv.result */
 	ahash_restore_req(areq, err);

 	/* Complete the ORIGINAL request. */
 	areq->base.complete(&areq->base, err);
 }

 static int ahash_op_unaligned(struct ahash_request *req,
 			      int (*op)(struct ahash_request *))
 {
 	int err;

 	err = ahash_save_req(req, ahash_op_unaligned_done);
 	if (err)
 		return err;

 	err = op(req);
 	if (err == -EINPROGRESS ||
 	    (err == -EBUSY && (ahash_request_flags(req) &
 			       CRYPTO_TFM_REQ_MAY_BACKLOG)))
 		return err;

 	ahash_restore_req(req, err);

 	return err;
 }

 static int crypto_ahash_op(struct ahash_request *req,
 			   int (*op)(struct ahash_request *))
 {
 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 	unsigned long alignmask = crypto_ahash_alignmask(tfm);

 	if ((unsigned long)req->result & alignmask)
 		return ahash_op_unaligned(req, op);

 	return op(req);
 }

 int crypto_ahash_final(struct ahash_request *req)
 {
 	return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
 }
 EXPORT_SYMBOL_GPL(crypto_ahash_final);

 int crypto_ahash_finup(struct ahash_request *req)
 {
 	return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
 }
 EXPORT_SYMBOL_GPL(crypto_ahash_finup);

 int crypto_ahash_digest(struct ahash_request *req)
 {
 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);

 	if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 		return -ENOKEY;

 	return crypto_ahash_op(req, tfm->digest);
 }
 EXPORT_SYMBOL_GPL(crypto_ahash_digest);

 static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
 {
 	struct ahash_request *areq = req->data;

 	if (err == -EINPROGRESS)
 		return;

 	ahash_restore_req(areq, err);

 	areq->base.complete(&areq->base, err);
 }

 static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 {
 	if (err)
 		goto out;

 	req->base.complete = ahash_def_finup_done2;

 	err = crypto_ahash_reqtfm(req)->final(req);
 	if (err == -EINPROGRESS ||
 	    (err == -EBUSY && (ahash_request_flags(req) &
 			       CRYPTO_TFM_REQ_MAY_BACKLOG)))
 		return err;

 out:
 	ahash_restore_req(req, err);
 	return err;
 }

 static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
 {
 	struct ahash_request *areq = req->data;

 	if (err == -EINPROGRESS) {
 		ahash_notify_einprogress(areq);
 		return;
 	}

 	areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;

 	err = ahash_def_finup_finish1(areq, err);
 	if (areq->priv)
 		return;

 	areq->base.complete(&areq->base, err);
 }

 static int ahash_def_finup(struct ahash_request *req)
 {
 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
 	int err;

 	err = ahash_save_req(req, ahash_def_finup_done1);
 	if (err)
 		return err;

 	err = tfm->update(req);
 	if (err == -EINPROGRESS ||
 	    (err == -EBUSY && (ahash_request_flags(req) &
 			       CRYPTO_TFM_REQ_MAY_BACKLOG)))
 		return err;

 	return ahash_def_finup_finish1(req, err);
 }

 static int ahash_no_export(struct ahash_request *req, void *out)
 {
 	return -ENOSYS;
 }

 static int ahash_no_import(struct ahash_request *req, const void *in)
 {
 	return -ENOSYS;
 }

 static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 {
 	struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 	struct ahash_alg *alg = crypto_ahash_alg(hash);

 	hash->setkey = ahash_nosetkey;
 	hash->export = ahash_no_export;
 	hash->import = ahash_no_import;

 	if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
 		return crypto_init_shash_ops_async(tfm);

 	hash->init = alg->init;
 	hash->update = alg->update;
 	hash->final = alg->final;
 	hash->finup = alg->finup ?: ahash_def_finup;
 	hash->digest = alg->digest;

 	if (alg->setkey) {
 		hash->setkey = alg->setkey;
 		if (!(alg->halg.base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
 			crypto_ahash_set_flags(hash, CRYPTO_TFM_NEED_KEY);
 	}
 	if (alg->export)
 		hash->export = alg->export;
 	if (alg->import)
 		hash->import = alg->import;

 	return 0;
 }

 static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
 {
 	if (alg->cra_type != &crypto_ahash_type)
 		return sizeof(struct crypto_shash *);

 	return crypto_alg_extsize(alg);
 }

 #ifdef CONFIG_NET
 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 {
 	struct crypto_report_hash rhash;

 	strncpy(rhash.type, "ahash", sizeof(rhash.type));

 	rhash.blocksize = alg->cra_blocksize;
 	rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;

 	if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
 		    sizeof(struct crypto_report_hash), &rhash))
 		goto nla_put_failure;
 	return 0;

 nla_put_failure:
 	return -EMSGSIZE;
 }
 #else
 static int crypto_ahash_report(struct sk_buff *skb, struct crypto_alg *alg)
 {
 	return -ENOSYS;
 }
 #endif

 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 	__attribute__ ((unused));
 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
 {
 	seq_printf(m, "type         : ahash\n");
 	seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
 					     "yes" : "no");
 	seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 	seq_printf(m, "digestsize   : %u\n",
 		   __crypto_hash_alg_common(alg)->digestsize);
 }

 const struct crypto_type crypto_ahash_type = {
 	.extsize = crypto_ahash_extsize,
 	.init_tfm = crypto_ahash_init_tfm,
 #ifdef CONFIG_PROC_FS
 	.show = crypto_ahash_show,
 #endif
 	.report = crypto_ahash_report,
 	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
 	.maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
 	.type = CRYPTO_ALG_TYPE_AHASH,
 	.tfmsize = offsetof(struct crypto_ahash, base),
 };
 EXPORT_SYMBOL_GPL(crypto_ahash_type);

 struct crypto_ahash *crypto_alloc_ahash(const char *alg_name, u32 type,
 					u32 mask)
 {
 	return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
 }
 EXPORT_SYMBOL_GPL(crypto_alloc_ahash);

 int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
 {
 	return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
 }
 EXPORT_SYMBOL_GPL(crypto_has_ahash);

 static int ahash_prepare_alg(struct ahash_alg *alg)
 {
 	struct crypto_alg *base = &alg->halg.base;

 	if (alg->halg.digestsize > PAGE_SIZE / 8 ||
 	    alg->halg.statesize > PAGE_SIZE / 8 ||
 	    alg->halg.statesize == 0)
 		return -EINVAL;

 	base->cra_type = &crypto_ahash_type;
 	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 	base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;

 	return 0;
 }

 int crypto_register_ahash(struct ahash_alg *alg)
 {
 	struct crypto_alg *base = &alg->halg.base;
 	int err;

 	err = ahash_prepare_alg(alg);
 	if (err)
 		return err;

 	return crypto_register_alg(base);
 }
 EXPORT_SYMBOL_GPL(crypto_register_ahash);

 int crypto_unregister_ahash(struct ahash_alg *alg)
 {
 	return crypto_unregister_alg(&alg->halg.base);
 }
 EXPORT_SYMBOL_GPL(crypto_unregister_ahash);

 int ahash_register_instance(struct crypto_template *tmpl,
 			    struct ahash_instance *inst)
 {
 	int err;

 	err = ahash_prepare_alg(&inst->alg);
 	if (err)
 		return err;

 	return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
 }
 EXPORT_SYMBOL_GPL(ahash_register_instance);

 void ahash_free_instance(struct crypto_instance *inst)
 {
 	crypto_drop_spawn(crypto_instance_ctx(inst));
 	kfree(ahash_instance(inst));
 }
 EXPORT_SYMBOL_GPL(ahash_free_instance);

 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 			    struct hash_alg_common *alg,
 			    struct crypto_instance *inst)
 {
 	return crypto_init_spawn2(&spawn->base, &alg->base, inst,
 				  &crypto_ahash_type);
 }
 EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);

 struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 {
 	struct crypto_alg *alg;

 	alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
 	return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
 }
 EXPORT_SYMBOL_GPL(ahash_attr_alg);

 bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
 {
 	struct crypto_alg *alg = &halg->base;

 	if (alg->cra_type != &crypto_ahash_type)
 		return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));

 	return __crypto_ahash_alg(alg)->setkey != NULL;
 }
 EXPORT_SYMBOL_GPL(crypto_hash_alg_has_setkey);

 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");
	/*
	* Asynchronous Cryptographic Hash operations.
	*
	* This is the asynchronous version of hash.c with notification of
	* completion via a callback.
	*
	* Copyright (c) 2008 Loc Ho <lho@amcc.com>
	*
	* 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/hash.h>
	#include <crypto/scatterwalk.h>
	#include <linux/bug.h>
	#include <linux/err.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/sched.h>
	#include <linux/slab.h>
	#include <linux/seq_file.h>
	#include <linux/cryptouser.h>
	#include <net/netlink.h>

	#include "internal.h"

	struct ahash_request_priv {
	crypto_completion_t complete;
	void *data;
	u8 *result;
	u32 flags;
	void *ubuf[] CRYPTO_MINALIGN_ATTR;
	};

	static inline struct ahash_alg crypto_ahash_alg(struct crypto_ahash hash)
	{
	return container_of(crypto_hash_alg_common(hash), struct ahash_alg,
	halg);
	}

	static int hash_walk_next(struct crypto_hash_walk *walk)
	{
	unsigned int alignmask = walk->alignmask;
	unsigned int offset = walk->offset;
	unsigned int nbytes = min(walk->entrylen,
	((unsigned int)(PAGE_SIZE)) - offset);

	if (walk->flags & CRYPTO_ALG_ASYNC)
	walk->data = kmap(walk->pg);
	else
	walk->data = kmap_atomic(walk->pg);
	walk->data += offset;

	if (offset & alignmask) {
	unsigned int unaligned = alignmask + 1 - (offset & alignmask);

	if (nbytes > unaligned)
	nbytes = unaligned;
	}

	walk->entrylen -= nbytes;
	return nbytes;
	}

	static int hash_walk_new_entry(struct crypto_hash_walk *walk)
	{
	struct scatterlist *sg;

	sg = walk->sg;
	walk->offset = sg->offset;
	walk->pg = sg_page(walk->sg) + (walk->offset >> PAGE_SHIFT);
	walk->offset = offset_in_page(walk->offset);
	walk->entrylen = sg->length;

	if (walk->entrylen > walk->total)
	walk->entrylen = walk->total;
	walk->total -= walk->entrylen;

	return hash_walk_next(walk);
	}

	int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
	{
	unsigned int alignmask = walk->alignmask;
	unsigned int nbytes = walk->entrylen;

	walk->data -= walk->offset;

	if (nbytes && walk->offset & alignmask && !err) {
	walk->offset = ALIGN(walk->offset, alignmask + 1);
	nbytes = min(nbytes,
	((unsigned int)(PAGE_SIZE)) - walk->offset);
	walk->entrylen -= nbytes;

	if (nbytes) {
	walk->data += walk->offset;
	return nbytes;
	}
	}

	if (walk->flags & CRYPTO_ALG_ASYNC)
	kunmap(walk->pg);
	else {
	kunmap_atomic(walk->data);
	/*
	* The may sleep test only makes sense for sync users.
	* Async users don't need to sleep here anyway.
	*/
	crypto_yield(walk->flags);
	}

	if (err)
	return err;

	if (nbytes) {
	walk->offset = 0;
	walk->pg++;
	return hash_walk_next(walk);
	}

	if (!walk->total)
	return 0;

	walk->sg = sg_next(walk->sg);

	return hash_walk_new_entry(walk);
	}
	EXPORT_SYMBOL_GPL(crypto_hash_walk_done);

	int crypto_hash_walk_first(struct ahash_request *req,
	struct crypto_hash_walk *walk)
	{
	walk->total = req->nbytes;

	if (!walk->total) {
	walk->entrylen = 0;
	return 0;
	}

	walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
	walk->sg = req->src;
	walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;

	return hash_walk_new_entry(walk);
	}
	EXPORT_SYMBOL_GPL(crypto_hash_walk_first);

	int crypto_ahash_walk_first(struct ahash_request *req,
	struct crypto_hash_walk *walk)
	{
	walk->total = req->nbytes;

	if (!walk->total) {
	walk->entrylen = 0;
	return 0;
	}

	walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
	walk->sg = req->src;
	walk->flags = req->base.flags & CRYPTO_TFM_REQ_MASK;
	walk->flags \|= CRYPTO_ALG_ASYNC;

	BUILD_BUG_ON(CRYPTO_TFM_REQ_MASK & CRYPTO_ALG_ASYNC);

	return hash_walk_new_entry(walk);
	}
	EXPORT_SYMBOL_GPL(crypto_ahash_walk_first);

	static int ahash_setkey_unaligned(struct crypto_ahash tfm, const u8 key,
	unsigned int keylen)
	{
	unsigned long alignmask = crypto_ahash_alignmask(tfm);
	int ret;
	u8 buffer, alignbuffer;
	unsigned long absize;

	absize = keylen + alignmask;
	buffer = kmalloc(absize, GFP_KERNEL);
	if (!buffer)
	return -ENOMEM;

	alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
	memcpy(alignbuffer, key, keylen);
	ret = tfm->setkey(tfm, alignbuffer, keylen);
	kzfree(buffer);
	return ret;
	}

	int crypto_ahash_setkey(struct crypto_ahash tfm, const u8 key,
	unsigned int keylen)
	{
	unsigned long alignmask = crypto_ahash_alignmask(tfm);
	int err;

	if ((unsigned long)key & alignmask)
	err = ahash_setkey_unaligned(tfm, key, keylen);
	else
	err = tfm->setkey(tfm, key, keylen);

	if (err)
	return err;

	crypto_ahash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
	return 0;
	}
	EXPORT_SYMBOL_GPL(crypto_ahash_setkey);

	static int ahash_nosetkey(struct crypto_ahash tfm, const u8 key,
	unsigned int keylen)
	{
	return -ENOSYS;
	}

	static inline unsigned int ahash_align_buffer_size(unsigned len,
	unsigned long mask)
	{
	return len + (mask & ~(crypto_tfm_ctx_alignment() - 1));
	}

	static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
	{
	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
	unsigned long alignmask = crypto_ahash_alignmask(tfm);
	unsigned int ds = crypto_ahash_digestsize(tfm);
	struct ahash_request_priv *priv;

	priv = kmalloc(sizeof(*priv) + ahash_align_buffer_size(ds, alignmask),
	(req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP) ?
	GFP_KERNEL : GFP_ATOMIC);
	if (!priv)
	return -ENOMEM;

	/*
	* WARNING: Voodoo programming below!
	*
	* The code below is obscure and hard to understand, thus explanation
	* is necessary. See include/crypto/hash.h and include/linux/crypto.h
	* to understand the layout of structures used here!
	*
	* The code here will replace portions of the ORIGINAL request with
	* pointers to new code and buffers so the hashing operation can store
	* the result in aligned buffer. We will call the modified request
	* an ADJUSTED request.
	*
	* The newly mangled request will look as such:
	*
	* req {
	* .result = ADJUSTED[new aligned buffer]
	* .base.complete = ADJUSTED[pointer to completion function]
	* .base.data = ADJUSTED[*req (pointer to self)]
	* .priv = ADJUSTED[new priv] {
	* .result = ORIGINAL(result)
	* .complete = ORIGINAL(base.complete)
	* .data = ORIGINAL(base.data)
	* }
	*/

	priv->result = req->result;
	priv->complete = req->base.complete;
	priv->data = req->base.data;
	priv->flags = req->base.flags;

	/*
	* WARNING: We do not backup req->priv here! The req->priv
	* is for internal use of the Crypto API and the
	* user must _NOT_ _EVER_ depend on it's content!
	*/

	req->result = PTR_ALIGN((u8 *)priv->ubuf, alignmask + 1);
	req->base.complete = cplt;
	req->base.data = req;
	req->priv = priv;

	return 0;
	}

	static void ahash_restore_req(struct ahash_request *req, int err)
	{
	struct ahash_request_priv *priv = req->priv;

	if (!err)
	memcpy(priv->result, req->result,
	crypto_ahash_digestsize(crypto_ahash_reqtfm(req)));

	/* Restore the original crypto request. */
	req->result = priv->result;

	ahash_request_set_callback(req, priv->flags,
	priv->complete, priv->data);
	req->priv = NULL;

	/* Free the req->priv.priv from the ADJUSTED request. */
	kzfree(priv);
	}

	static void ahash_notify_einprogress(struct ahash_request *req)
	{
	struct ahash_request_priv *priv = req->priv;
	struct crypto_async_request oreq;

	oreq.data = priv->data;

	priv->complete(&oreq, -EINPROGRESS);
	}

	static void ahash_op_unaligned_done(struct crypto_async_request *req, int err)
	{
	struct ahash_request *areq = req->data;

	if (err == -EINPROGRESS) {
	ahash_notify_einprogress(areq);
	return;
	}

	/*
	* Restore the original request, see ahash_op_unaligned() for what
	* goes where.
	*
	* The "struct ahash_request *req" here is in fact the "req.base"
	* from the ADJUSTED request from ahash_op_unaligned(), thus as it
	* is a pointer to self, it is also the ADJUSTED "req" .
	*/

	/* First copy req->result into req->priv.result */
	ahash_restore_req(areq, err);

	/* Complete the ORIGINAL request. */
	areq->base.complete(&areq->base, err);
	}

	static int ahash_op_unaligned(struct ahash_request *req,
	int (op)(struct ahash_request ))
	{
	int err;

	err = ahash_save_req(req, ahash_op_unaligned_done);
	if (err)
	return err;

	err = op(req);
	if (err == -EINPROGRESS \|\|
	(err == -EBUSY && (ahash_request_flags(req) &
	CRYPTO_TFM_REQ_MAY_BACKLOG)))
	return err;

	ahash_restore_req(req, err);

	return err;
	}

	static int crypto_ahash_op(struct ahash_request *req,
	int (op)(struct ahash_request ))
	{
	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
	unsigned long alignmask = crypto_ahash_alignmask(tfm);

	if ((unsigned long)req->result & alignmask)
	return ahash_op_unaligned(req, op);

	return op(req);
	}

	int crypto_ahash_final(struct ahash_request *req)
	{
	return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->final);
	}
	EXPORT_SYMBOL_GPL(crypto_ahash_final);

	int crypto_ahash_finup(struct ahash_request *req)
	{
	return crypto_ahash_op(req, crypto_ahash_reqtfm(req)->finup);
	}
	EXPORT_SYMBOL_GPL(crypto_ahash_finup);

	int crypto_ahash_digest(struct ahash_request *req)
	{
	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);

	if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
	return -ENOKEY;

	return crypto_ahash_op(req, tfm->digest);
	}
	EXPORT_SYMBOL_GPL(crypto_ahash_digest);

	static void ahash_def_finup_done2(struct crypto_async_request *req, int err)
	{
	struct ahash_request *areq = req->data;

	if (err == -EINPROGRESS)
	return;

	ahash_restore_req(areq, err);

	areq->base.complete(&areq->base, err);
	}

	static int ahash_def_finup_finish1(struct ahash_request *req, int err)
	{
	if (err)
	goto out;

	req->base.complete = ahash_def_finup_done2;

	err = crypto_ahash_reqtfm(req)->final(req);
	if (err == -EINPROGRESS \|\|
	(err == -EBUSY && (ahash_request_flags(req) &
	CRYPTO_TFM_REQ_MAY_BACKLOG)))
	return err;

	out:
	ahash_restore_req(req, err);
	return err;
	}

	static void ahash_def_finup_done1(struct crypto_async_request *req, int err)
	{
	struct ahash_request *areq = req->data;

	if (err == -EINPROGRESS) {
	ahash_notify_einprogress(areq);
	return;
	}

	areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;

	err = ahash_def_finup_finish1(areq, err);
	if (areq->priv)
	return;

	areq->base.complete(&areq->base, err);
	}

	static int ahash_def_finup(struct ahash_request *req)
	{
	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
	int err;

	err = ahash_save_req(req, ahash_def_finup_done1);
	if (err)
	return err;

	err = tfm->update(req);
	if (err == -EINPROGRESS \|\|
	(err == -EBUSY && (ahash_request_flags(req) &
	CRYPTO_TFM_REQ_MAY_BACKLOG)))
	return err;

	return ahash_def_finup_finish1(req, err);
	}

	static int ahash_no_export(struct ahash_request req, void out)
	{
	return -ENOSYS;
	}

	static int ahash_no_import(struct ahash_request req, const void in)
	{
	return -ENOSYS;
	}

	static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
	{
	struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
	struct ahash_alg *alg = crypto_ahash_alg(hash);

	hash->setkey = ahash_nosetkey;
	hash->export = ahash_no_export;
	hash->import = ahash_no_import;

	if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
	return crypto_init_shash_ops_async(tfm);

	hash->init = alg->init;
	hash->update = alg->update;
	hash->final = alg->final;
	hash->finup = alg->finup ?: ahash_def_finup;
	hash->digest = alg->digest;

	if (alg->setkey) {
	hash->setkey = alg->setkey;
	if (!(alg->halg.base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
	crypto_ahash_set_flags(hash, CRYPTO_TFM_NEED_KEY);
	}
	if (alg->export)
	hash->export = alg->export;
	if (alg->import)
	hash->import = alg->import;

	return 0;
	}

	static unsigned int crypto_ahash_extsize(struct crypto_alg *alg)
	{
	if (alg->cra_type != &crypto_ahash_type)
	return sizeof(struct crypto_shash *);

	return crypto_alg_extsize(alg);
	}

	#ifdef CONFIG_NET
	static int crypto_ahash_report(struct sk_buff skb, struct crypto_alg alg)
	{
	struct crypto_report_hash rhash;

	strncpy(rhash.type, "ahash", sizeof(rhash.type));

	rhash.blocksize = alg->cra_blocksize;
	rhash.digestsize = __crypto_hash_alg_common(alg)->digestsize;

	if (nla_put(skb, CRYPTOCFGA_REPORT_HASH,
	sizeof(struct crypto_report_hash), &rhash))
	goto nla_put_failure;
	return 0;

	nla_put_failure:
	return -EMSGSIZE;
	}
	#else
	static int crypto_ahash_report(struct sk_buff skb, struct crypto_alg alg)
	{
	return -ENOSYS;
	}
	#endif

	static void crypto_ahash_show(struct seq_file m, struct crypto_alg alg)
	__attribute__ ((unused));
	static void crypto_ahash_show(struct seq_file m, struct crypto_alg alg)
	{
	seq_printf(m, "type : ahash\n");
	seq_printf(m, "async : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
	"yes" : "no");
	seq_printf(m, "blocksize : %u\n", alg->cra_blocksize);
	seq_printf(m, "digestsize : %u\n",
	__crypto_hash_alg_common(alg)->digestsize);
	}

	const struct crypto_type crypto_ahash_type = {
	.extsize = crypto_ahash_extsize,
	.init_tfm = crypto_ahash_init_tfm,
	#ifdef CONFIG_PROC_FS
	.show = crypto_ahash_show,
	#endif
	.report = crypto_ahash_report,
	.maskclear = ~CRYPTO_ALG_TYPE_MASK,
	.maskset = CRYPTO_ALG_TYPE_AHASH_MASK,
	.type = CRYPTO_ALG_TYPE_AHASH,
	.tfmsize = offsetof(struct crypto_ahash, base),
	};
	EXPORT_SYMBOL_GPL(crypto_ahash_type);

	struct crypto_ahash crypto_alloc_ahash(const char alg_name, u32 type,
	u32 mask)
	{
	return crypto_alloc_tfm(alg_name, &crypto_ahash_type, type, mask);
	}
	EXPORT_SYMBOL_GPL(crypto_alloc_ahash);

	int crypto_has_ahash(const char *alg_name, u32 type, u32 mask)
	{
	return crypto_type_has_alg(alg_name, &crypto_ahash_type, type, mask);
	}
	EXPORT_SYMBOL_GPL(crypto_has_ahash);

	static int ahash_prepare_alg(struct ahash_alg *alg)
	{
	struct crypto_alg *base = &alg->halg.base;

	if (alg->halg.digestsize > PAGE_SIZE / 8 \|\|
	alg->halg.statesize > PAGE_SIZE / 8 \|\|
	alg->halg.statesize == 0)
	return -EINVAL;

	base->cra_type = &crypto_ahash_type;
	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
	base->cra_flags \|= CRYPTO_ALG_TYPE_AHASH;

	return 0;
	}

	int crypto_register_ahash(struct ahash_alg *alg)
	{
	struct crypto_alg *base = &alg->halg.base;
	int err;

	err = ahash_prepare_alg(alg);
	if (err)
	return err;

	return crypto_register_alg(base);
	}
	EXPORT_SYMBOL_GPL(crypto_register_ahash);

	int crypto_unregister_ahash(struct ahash_alg *alg)
	{
	return crypto_unregister_alg(&alg->halg.base);
	}
	EXPORT_SYMBOL_GPL(crypto_unregister_ahash);

	int ahash_register_instance(struct crypto_template *tmpl,
	struct ahash_instance *inst)
	{
	int err;

	err = ahash_prepare_alg(&inst->alg);
	if (err)
	return err;

	return crypto_register_instance(tmpl, ahash_crypto_instance(inst));
	}
	EXPORT_SYMBOL_GPL(ahash_register_instance);

	void ahash_free_instance(struct crypto_instance *inst)
	{
	crypto_drop_spawn(crypto_instance_ctx(inst));
	kfree(ahash_instance(inst));
	}
	EXPORT_SYMBOL_GPL(ahash_free_instance);

	int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
	struct hash_alg_common *alg,
	struct crypto_instance *inst)
	{
	return crypto_init_spawn2(&spawn->base, &alg->base, inst,
	&crypto_ahash_type);
	}
	EXPORT_SYMBOL_GPL(crypto_init_ahash_spawn);

	struct hash_alg_common ahash_attr_alg(struct rtattr rta, u32 type, u32 mask)
	{
	struct crypto_alg *alg;

	alg = crypto_attr_alg2(rta, &crypto_ahash_type, type, mask);
	return IS_ERR(alg) ? ERR_CAST(alg) : __crypto_hash_alg_common(alg);
	}
	EXPORT_SYMBOL_GPL(ahash_attr_alg);

	bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
	{
	struct crypto_alg *alg = &halg->base;

	if (alg->cra_type != &crypto_ahash_type)
	return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));

	return __crypto_ahash_alg(alg)->setkey != NULL;
	}
	EXPORT_SYMBOL_GPL(crypto_hash_alg_has_setkey);

	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("Asynchronous cryptographic hash type");