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: Herbert Xu <herbert@gondor.apana.org.au>
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b8454eebe3
Коммит
20036252fc
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@ -13,7 +13,8 @@
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*
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*/
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#include <crypto/algapi.h>
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#include <crypto/internal/hash.h>
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#include <crypto/scatterwalk.h>
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#include <linux/err.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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@ -23,6 +24,94 @@
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#include "internal.h"
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static int hash_walk_next(struct crypto_hash_walk *walk)
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{
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unsigned int alignmask = walk->alignmask;
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unsigned int offset = walk->offset;
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unsigned int nbytes = min(walk->entrylen,
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((unsigned int)(PAGE_SIZE)) - offset);
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walk->data = crypto_kmap(walk->pg, 0);
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walk->data += offset;
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if (offset & alignmask)
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nbytes = alignmask + 1 - (offset & alignmask);
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walk->entrylen -= nbytes;
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return nbytes;
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}
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static int hash_walk_new_entry(struct crypto_hash_walk *walk)
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{
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struct scatterlist *sg;
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sg = walk->sg;
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walk->pg = sg_page(sg);
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walk->offset = sg->offset;
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walk->entrylen = sg->length;
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if (walk->entrylen > walk->total)
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walk->entrylen = walk->total;
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walk->total -= walk->entrylen;
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return hash_walk_next(walk);
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}
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int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
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{
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unsigned int alignmask = walk->alignmask;
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unsigned int nbytes = walk->entrylen;
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walk->data -= walk->offset;
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if (nbytes && walk->offset & alignmask && !err) {
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walk->offset += alignmask - 1;
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walk->offset = ALIGN(walk->offset, alignmask + 1);
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walk->data += walk->offset;
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nbytes = min(nbytes,
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((unsigned int)(PAGE_SIZE)) - walk->offset);
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walk->entrylen -= nbytes;
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return nbytes;
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}
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crypto_kunmap(walk->data, 0);
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crypto_yield(walk->flags);
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if (err)
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return err;
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walk->offset = 0;
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if (nbytes)
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return hash_walk_next(walk);
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if (!walk->total)
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return 0;
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walk->sg = scatterwalk_sg_next(walk->sg);
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return hash_walk_new_entry(walk);
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}
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EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
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int crypto_hash_walk_first(struct ahash_request *req,
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struct crypto_hash_walk *walk)
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{
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walk->total = req->nbytes;
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if (!walk->total)
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return 0;
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walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
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walk->sg = req->src;
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walk->flags = req->base.flags;
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return hash_walk_new_entry(walk);
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}
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EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
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static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
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unsigned int keylen)
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{
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@ -0,0 +1,41 @@
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/*
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* Hash algorithms.
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*
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* Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#ifndef _CRYPTO_INTERNAL_HASH_H
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#define _CRYPTO_INTERNAL_HASH_H
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#include <crypto/algapi.h>
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struct ahash_request;
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struct scatterlist;
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struct crypto_hash_walk {
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char *data;
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unsigned int offset;
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unsigned int alignmask;
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struct page *pg;
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unsigned int entrylen;
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unsigned int total;
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struct scatterlist *sg;
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unsigned int flags;
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};
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int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err);
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int crypto_hash_walk_first(struct ahash_request *req,
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struct crypto_hash_walk *walk);
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#endif /* _CRYPTO_INTERNAL_HASH_H */
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