2008-07-09 07:37:35

by Herbert Xu

[permalink] [raw]
Subject: [PATCH] crypto: hash - Added scatter list walking helper

Hi:

This patch lets us convert existing software implementations
of hash algorithms to use the ahash interface. It's similar
to how the blkcipher walking works.

commit 505ae158f41441b9c7e65116b9cb4df7ab1d6753
Author: Herbert Xu <[email protected]>
Date: Mon Jul 7 22:19:53 2008 +0800

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 <[email protected]>

diff --git a/crypto/ahash.c b/crypto/ahash.c
index e6e5906..bb0239c 100644
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -13,7 +13,8 @@
*
*/

-#include <crypto/algapi.h>
+#include <crypto/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)
{
diff --git a/include/crypto/hash.h b/include/crypto/hash.h
new file mode 100644
index 0000000..f9d54c0
--- /dev/null
+++ b/include/crypto/hash.h
@@ -0,0 +1,41 @@
+/*
+ * Hash algorithms.
+ *
+ * Copyright (c) 2008 Herbert Xu <[email protected]>
+ *
+ * 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_HASH_H
+#define _CRYPTO_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_HASH_H */
+
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt


2008-07-10 07:58:36

by Herbert Xu

[permalink] [raw]
Subject: Re: [PATCH] crypto: hash - Added scatter list walking helper

On Wed, Jul 09, 2008 at 03:37:32PM +0800, Herbert Xu wrote:
>
> diff --git a/include/crypto/hash.h b/include/crypto/hash.h
> new file mode 100644
> index 0000000..f9d54c0
> --- /dev/null
> +++ b/include/crypto/hash.h

I've moved this file to include/crypto/internal since it's meant
to be used by ahash implementors rather than uesrs.

Cheers,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbe[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
--
diff --git a/crypto/ahash.c b/crypto/ahash.c
index bb0239c..27128f2 100644
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -13,7 +13,7 @@
*
*/

-#include <crypto/hash.h>
+#include <crypto/internal/hash.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/kernel.h>
diff --git a/crypto/crc32c.c b/crypto/crc32c.c
index 7049a98..a882d9e 100644
--- a/crypto/crc32c.c
+++ b/crypto/crc32c.c
@@ -14,7 +14,7 @@
*
*/

-#include <crypto/hash.h>
+#include <crypto/internal/hash.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
diff --git a/include/crypto/hash.h b/include/crypto/hash.h
deleted file mode 100644
index f9d54c0..0000000
--- a/include/crypto/hash.h
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- * Hash algorithms.
- *
- * Copyright (c) 2008 Herbert Xu <[email protected]>
- *
- * 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_HASH_H
-#define _CRYPTO_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_HASH_H */
-
diff --git a/include/crypto/internal/hash.h b/include/crypto/internal/hash.h
new file mode 100644
index 0000000..93ac422
--- /dev/null
+++ b/include/crypto/internal/hash.h
@@ -0,0 +1,41 @@
+/*
+ * Hash algorithms.
+ *
+ * Copyright (c) 2008 Herbert Xu <[email protected]>
+ *
+ * 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 */
+