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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/s390/crypto/sha_common.c
10817 views
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/*

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 * Cryptographic API.

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 *

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 * s390 generic implementation of the SHA Secure Hash Algorithms.

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 *

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 * Copyright IBM Corp. 2007

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 * Author(s): Jan Glauber ([email protected])

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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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#include <crypto/internal/hash.h>

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#include "sha.h"

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#include "crypt_s390.h"

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int s390_sha_update(struct shash_desc *desc, const u8 *data, unsigned int len)

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{

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	struct s390_sha_ctx *ctx = shash_desc_ctx(desc);

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	unsigned int bsize = crypto_shash_blocksize(desc->tfm);

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	unsigned int index;

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	int ret;

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	/* how much is already in the buffer? */

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	index = ctx->count & (bsize - 1);

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	ctx->count += len;

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	if ((index + len) < bsize)

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		goto store;

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	/* process one stored block */

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	if (index) {

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		memcpy(ctx->buf + index, data, bsize - index);

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		ret = crypt_s390_kimd(ctx->func, ctx->state, ctx->buf, bsize);

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		BUG_ON(ret != bsize);

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		data += bsize - index;

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		len -= bsize - index;

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		index = 0;

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	}

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	/* process as many blocks as possible */

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	if (len >= bsize) {

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		ret = crypt_s390_kimd(ctx->func, ctx->state, data,

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				      len & ~(bsize - 1));

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		BUG_ON(ret != (len & ~(bsize - 1)));

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		data += ret;

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		len -= ret;

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	}

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store:

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	if (len)

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		memcpy(ctx->buf + index , data, len);

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	return 0;

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}

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EXPORT_SYMBOL_GPL(s390_sha_update);

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int s390_sha_final(struct shash_desc *desc, u8 *out)

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{

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	struct s390_sha_ctx *ctx = shash_desc_ctx(desc);

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	unsigned int bsize = crypto_shash_blocksize(desc->tfm);

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	u64 bits;

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	unsigned int index, end, plen;

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	int ret;

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	/* SHA-512 uses 128 bit padding length */

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	plen = (bsize > SHA256_BLOCK_SIZE) ? 16 : 8;

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	/* must perform manual padding */

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	index = ctx->count & (bsize - 1);

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	end = (index < bsize - plen) ? bsize : (2 * bsize);

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	/* start pad with 1 */

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	ctx->buf[index] = 0x80;

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	index++;

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	/* pad with zeros */

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	memset(ctx->buf + index, 0x00, end - index - 8);

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	/*

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	 * Append message length. Well, SHA-512 wants a 128 bit length value,

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	 * nevertheless we use u64, should be enough for now...

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	 */

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	bits = ctx->count * 8;

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	memcpy(ctx->buf + end - 8, &bits, sizeof(bits));

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	ret = crypt_s390_kimd(ctx->func, ctx->state, ctx->buf, end);

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	BUG_ON(ret != end);

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	/* copy digest to out */

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	memcpy(out, ctx->state, crypto_shash_digestsize(desc->tfm));

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	/* wipe context */

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	memset(ctx, 0, sizeof *ctx);

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	return 0;

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}

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EXPORT_SYMBOL_GPL(s390_sha_final);

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MODULE_LICENSE("GPL");

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MODULE_DESCRIPTION("s390 SHA cipher common functions");

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