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Commit 20036252 authored by Herbert Xu's avatar Herbert Xu
Browse files

crypto: hash - Added scatter list walking helper 



This patch adds the walking helpers for hash algorithms akin to
those of block ciphers.  This is a necessary step before we can
reimplement existing hash algorithms using the new ahash interface.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent b8454eeb

crypto/ahash.c

+90 −1
Original line number Diff line number Diff line
@@ -13,7 +13,8 @@ 
 *

 */



#include <crypto/algapi.h>

#include <crypto/internal/hash.h>

#include <crypto/scatterwalk.h>

#include <linux/err.h>

#include <linux/kernel.h>

#include <linux/module.h>
@@ -23,6 +24,94 @@ 


#include "internal.h"



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);



	walk->data = crypto_kmap(walk->pg, 0);

	walk->data += offset;



	if (offset & alignmask)

		nbytes = alignmask + 1 - (offset & alignmask);



	walk->entrylen -= nbytes;

	return nbytes;

}



static int hash_walk_new_entry(struct crypto_hash_walk *walk)

{

	struct scatterlist *sg;



	sg = walk->sg;

	walk->pg = sg_page(sg);

	walk->offset = sg->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 += alignmask - 1;

		walk->offset = ALIGN(walk->offset, alignmask + 1);

		walk->data += walk->offset;



		nbytes = min(nbytes,

			     ((unsigned int)(PAGE_SIZE)) - walk->offset);

		walk->entrylen -= nbytes;



		return nbytes;

	}



	crypto_kunmap(walk->data, 0);

	crypto_yield(walk->flags);



	if (err)

		return err;



	walk->offset = 0;



	if (nbytes)

		return hash_walk_next(walk);



	if (!walk->total)

		return 0;



	walk->sg = scatterwalk_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)

		return 0;



	walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));

	walk->sg = req->src;

	walk->flags = req->base.flags;



	return hash_walk_new_entry(walk);

}

EXPORT_SYMBOL_GPL(crypto_hash_walk_first);



static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,

				unsigned int keylen)

{

include/crypto/internal/hash.h

0 → 100644
+41 −0
Original line number Diff line number Diff line 
/*

 * Hash algorithms.

 * 

 * 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.

 *

 */



#ifndef _CRYPTO_INTERNAL_HASH_H

#define _CRYPTO_INTERNAL_HASH_H



#include <crypto/algapi.h>



struct ahash_request;

struct scatterlist;



struct crypto_hash_walk {

	char *data;



	unsigned int offset;

	unsigned int alignmask;



	struct page *pg;

	unsigned int entrylen;



	unsigned int total;

	struct scatterlist *sg;



	unsigned int flags;

};



int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err);

int crypto_hash_walk_first(struct ahash_request *req,

			   struct crypto_hash_walk *walk);



#endif	/* _CRYPTO_INTERNAL_HASH_H */