* Huang Ying | 2009-06-11 15:10:26 [+0800]:
>GHASH is implemented as a shash algorithm. The actual implementation
>is copied from gcm.c. This makes it possible to add
>architecture/hardware accelerated GHASH implementation.
>
>Signed-off-by: Huang Ying <ying.huang@xxxxxxxxx>
>
>---
> crypto/Kconfig | 7 +
> crypto/Makefile | 2
> crypto/ghash-generic.c | 179 +++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 188 insertions(+)
>
>--- /dev/null
>+++ b/crypto/ghash-generic.c
>@@ -0,0 +1,179 @@
>+/*
>+ * GHASH: digest algorithm for GCM (Galois/Counter Mode).
>+ *
>+ * Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@xxxxxx>
>+ * Copyright (c) 2009 Intel Corp.
>+ * Author: Huang Ying <ying.huang@xxxxxxxxx>
>+ *
>+ * The algorithm implementation is copied from gcm.c.
>+ *
>+ * This program is free software; you can redistribute it and/or modify it
>+ * under the terms of the GNU General Public License version 2 as published
>+ * by the Free Software Foundation.
>+ */
>+
>+#include <linux/module.h>
>+#include <linux/init.h>
>+#include <linux/kernel.h>
>+#include <linux/crypto.h>
>+#include <crypto/gf128mul.h>
>+#include <crypto/algapi.h>
>+#include <crypto/internal/hash.h>
Do you mind to sort them?
>+
>+#define GHASH_BLOCK_SIZE 16
>+#define GHASH_DIGEST_SIZE 16
>+
>+struct ghash_ctx {
>+ struct gf128mul_4k *gf128;
>+};
>+
>+struct ghash_desc_ctx {
>+ u8 buffer[16];
>+ u32 bytes;
>+};
>+
>+static int ghash_init(struct shash_desc *desc)
>+{
>+ struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
>+
>+ dctx->bytes = 0;
>+ memset(dctx->buffer, 0, 16);
>+
you could memset() the whole struct at once
>+ return 0;
>+}
>+
>+static int ghash_setkey(struct crypto_shash *tfm,
>+ const u8 *key, unsigned int keylen)
>+{
>+ struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
>+
>+ if (keylen != 16) {
>+ crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
>+ return -EINVAL;
>+ }
>+
>+ if (ctx->gf128)
>+ gf128mul_free_4k(ctx->gf128);
>+ ctx->gf128 = gf128mul_init_4k_lle((be128 *)key);
>+ if (!ctx->gf128)
>+ return -ENOMEM;
>+
>+ return 0;
>+}
>+
>+static int ghash_update(struct shash_desc *desc,
>+ const u8 *src, unsigned int srclen)
>+{
>+ struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
>+ struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
>+ u8 *dst = dctx->buffer;
>+
>+ if (dctx->bytes) {
>+ int n = min(srclen, dctx->bytes);
>+ u8 *pos = dst + (16 - dctx->bytes);
>+
>+ dctx->bytes -= n;
>+ srclen -= n;
>+
>+ while (n--)
>+ *pos++ ^= *src++;
>+
>+ if (!dctx->bytes)
>+ gf128mul_4k_lle((be128 *)dst, ctx->gf128);
>+ }
>+
>+ while (srclen >= 16) {
>+ crypto_xor(dst, src, 16);
>+ gf128mul_4k_lle((be128 *)dst, ctx->gf128);
>+ src += 16;
>+ srclen -= 16;
>+ }
>+
>+ if (srclen) {
>+ dctx->bytes = 16 - srclen;
>+ while (srclen--)
>+ *dst++ ^= *src++;
>+ }
>+
16 here looks like GHASH_BLOCK_SIZE to me
>+ return 0;
>+}
>+
>+static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
>+{
>+ u8 *dst = dctx->buffer;
>+
>+ if (dctx->bytes) {
>+ u8 *tmp = dst + (16 - dctx->bytes);
>+
>+ while (dctx->bytes--)
>+ *tmp++ ^= 0;
>+
>+ gf128mul_4k_lle((be128 *)dst, ctx->gf128);
>+ }
>+
>+ dctx->bytes = 0;
>+}
>+
>+static int ghash_final(struct shash_desc *desc, u8 *dst)
>+{
>+ struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
>+ struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
>+ u8 *buf = dctx->buffer;
>+
>+ ghash_flush(ctx, dctx);
>+ memcpy(dst, buf, 16);
>+
>+ return 0;
>+}
>+
>+static int ghash_init_tfm(struct crypto_tfm *tfm)
>+{
>+ struct ghash_ctx *ctx = crypto_tfm_ctx(tfm);
>+ ctx->gf128 = NULL;
Unless I'm mistaken, this is called once on allocation and this ctx is
allocated via kzalloc().
>+ return 0;
>+}
>+
>+static void ghash_exit_tfm(struct crypto_tfm *tfm)
>+{
>+ struct ghash_ctx *ctx = crypto_tfm_ctx(tfm);
>+ if (ctx->gf128)
>+ gf128mul_free_4k(ctx->gf128);
>+}
>+
>+static struct shash_alg ghash_alg = {
>+ .digestsize = GHASH_DIGEST_SIZE,
>+ .init = ghash_init,
>+ .update = ghash_update,
>+ .final = ghash_final,
>+ .setkey = ghash_setkey,
>+ .descsize = sizeof(struct ghash_desc_ctx),
>+ .base = {
>+ .cra_name = "ghash",
>+ .cra_driver_name = "ghash-generic",
>+ .cra_priority = 100,
>+ .cra_flags = CRYPTO_ALG_TYPE_SHASH,
>+ .cra_blocksize = GHASH_BLOCK_SIZE,
>+ .cra_ctxsize = sizeof(struct ghash_ctx),
>+ .cra_module = THIS_MODULE,
>+ .cra_list = LIST_HEAD_INIT(ghash_alg.base.cra_list),
>+ .cra_init = ghash_init_tfm,
>+ .cra_exit = ghash_exit_tfm,
>+ },
>+};
>+
>+static int __init ghash_mod_init(void)
>+{
>+ return crypto_register_shash(&ghash_alg);
>+}
>+
>+static void __exit ghash_mod_exit(void)
>+{
>+ crypto_unregister_shash(&ghash_alg);
>+}
>+
>+module_init(ghash_mod_init);
>+module_exit(ghash_mod_exit);
>+
>+MODULE_LICENSE("GPL");
>+MODULE_DESCRIPTION("GHASH Message Digest Algorithm");
>+MODULE_ALIAS("ghash");
>--- a/crypto/Kconfig
>+++ b/crypto/Kconfig
>@@ -419,6 +419,13 @@ config CRYPTO_WP512
> See also:
> <http://planeta.terra.com.br/informatica/paulobarreto/WhirlpoolPage.html>
>
>+config CRYPTO_GHASH
>+ tristate "GHASH digest algorithm"
>+ select CRYPTO_SHASH
>+ select CRYPTO_GF128MUL
>+ help
>+ GHASH is message digest algorithm for GCM (Galois/Counter Mode).
>+
Could you please move it to the 'G' section
> comment "Ciphers"
>
> config CRYPTO_AES
>--- a/crypto/Makefile
>+++ b/crypto/Makefile
>@@ -83,6 +83,8 @@ obj-$(CONFIG_CRYPTO_RNG2) += rng.o
> obj-$(CONFIG_CRYPTO_RNG2) += krng.o
> obj-$(CONFIG_CRYPTO_ANSI_CPRNG) += ansi_cprng.o
> obj-$(CONFIG_CRYPTO_TEST) += tcrypt.o
>+obj-$(CONFIG_CRYPTO_MD5) += md5.o
md5?
>+obj-$(CONFIG_CRYPTO_GHASH) += ghash-generic.o
>
> #
> # generic algorithms and the async_tx api
>
>
Sebastian
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