crypto: powerpc/md5 - glue

/*

 * Glue code for MD5 implementation for PPC assembler

 *

 * Based on generic implementation.

 *

 * Copyright (c) 2015 Markus Stockhausen <stockhausen@collogia.de>

 *

 * 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 <linux/init.h>

#include <linux/module.h>

#include <linux/mm.h>

#include <linux/cryptohash.h>

#include <linux/types.h>

#include <crypto/md5.h>

#include <asm/byteorder.h>

extern void ppc_md5_transform(u32 *state, const u8 *src, u32 blocks);

static inline void ppc_md5_clear_context(struct md5_state *sctx)

{

	int count = sizeof(struct md5_state) >> 2;

	u32 *ptr = (u32 *)sctx;

	/* make sure we can clear the fast way */

	BUILD_BUG_ON(sizeof(struct md5_state) % 4);

	do { *ptr++ = 0; } while (--count);

}

static int ppc_md5_init(struct shash_desc *desc)

{

	struct md5_state *sctx = shash_desc_ctx(desc);

	sctx->hash[0] = 0x67452301;

	sctx->hash[1] = 0xefcdab89;

	sctx->hash[2] = 0x98badcfe;

	sctx->hash[3] =	0x10325476;

	sctx->byte_count = 0;

	return 0;

}

static int ppc_md5_update(struct shash_desc *desc, const u8 *data,

			unsigned int len)

{

	struct md5_state *sctx = shash_desc_ctx(desc);

	const unsigned int offset = sctx->byte_count & 0x3f;

	unsigned int avail = 64 - offset;

	const u8 *src = data;

	sctx->byte_count += len;

	if (avail > len) {

		memcpy((char *)sctx->block + offset, src, len);

		return 0;

	}

	if (offset) {

		memcpy((char *)sctx->block + offset, src, avail);

		ppc_md5_transform(sctx->hash, (const u8 *)sctx->block, 1);

		len -= avail;

		src += avail;

	}

	if (len > 63) {

		ppc_md5_transform(sctx->hash, src, len >> 6);

		src += len & ~0x3f;

		len &= 0x3f;

	}

	memcpy((char *)sctx->block, src, len);

	return 0;

}

static int ppc_md5_final(struct shash_desc *desc, u8 *out)

{

	struct md5_state *sctx = shash_desc_ctx(desc);

	const unsigned int offset = sctx->byte_count & 0x3f;

	const u8 *src = (const u8 *)sctx->block;

	u8 *p = (u8 *)src + offset;

	int padlen = 55 - offset;

	__le64 *pbits = (__le64 *)((char *)sctx->block + 56);

	__le32 *dst = (__le32 *)out;

	*p++ = 0x80;

	if (padlen < 0) {

		memset(p, 0x00, padlen + sizeof (u64));

		ppc_md5_transform(sctx->hash, src, 1);

		p = (char *)sctx->block;

		padlen = 56;

	}

	memset(p, 0, padlen);

	*pbits = cpu_to_le64(sctx->byte_count << 3);

	ppc_md5_transform(sctx->hash, src, 1);

	dst[0] = cpu_to_le32(sctx->hash[0]);

	dst[1] = cpu_to_le32(sctx->hash[1]);

	dst[2] = cpu_to_le32(sctx->hash[2]);

	dst[3] = cpu_to_le32(sctx->hash[3]);

	ppc_md5_clear_context(sctx);

	return 0;

}

static int ppc_md5_export(struct shash_desc *desc, void *out)

{

	struct md5_state *sctx = shash_desc_ctx(desc);

	memcpy(out, sctx, sizeof(*sctx));

	return 0;

}

static int ppc_md5_import(struct shash_desc *desc, const void *in)

{

	struct md5_state *sctx = shash_desc_ctx(desc);

	memcpy(sctx, in, sizeof(*sctx));

	return 0;

}

static struct shash_alg alg = {

	.digestsize	=	MD5_DIGEST_SIZE,

	.init		=	ppc_md5_init,

	.update		=	ppc_md5_update,

	.final		=	ppc_md5_final,

	.export		=	ppc_md5_export,

	.import		=	ppc_md5_import,

	.descsize	=	sizeof(struct md5_state),

	.statesize	=	sizeof(struct md5_state),

	.base		=	{

		.cra_name	=	"md5",

		.cra_driver_name=	"md5-ppc",

		.cra_priority	=	200,

		.cra_flags	=	CRYPTO_ALG_TYPE_SHASH,

		.cra_blocksize	=	MD5_HMAC_BLOCK_SIZE,

		.cra_module	=	THIS_MODULE,

	}

};

static int __init ppc_md5_mod_init(void)

{

	return crypto_register_shash(&alg);

}

static void __exit ppc_md5_mod_fini(void)

{

	crypto_unregister_shash(&alg);

}

module_init(ppc_md5_mod_init);

module_exit(ppc_md5_mod_fini);

MODULE_LICENSE("GPL");

MODULE_DESCRIPTION("MD5 Secure Hash Algorithm, PPC assembler");

MODULE_ALIAS_CRYPTO("md5");

MODULE_ALIAS_CRYPTO("md5-ppc");