sha_common.c

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/*
 * Cryptographic API.
 *
 * s390 generic implementation of the SHA Secure Hash Algorithms.
 *
 * Copyright IBM Corp. 2007
 * Author(s): Jan Glauber ([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.
 *
 */

#include <crypto/internal/hash.h>
#include <linux/module.h>
#include "sha.h"
#include "crypt_s390.h"

int s390_sha_update(struct shash_desc *desc, const u8 *data, unsigned int len)
{
    struct s390_sha_ctx *ctx = shash_desc_ctx(desc);
    unsigned int bsize = crypto_shash_blocksize(desc->tfm);
    unsigned int index;
    int ret;

    /* how much is already in the buffer? */
    index = ctx->count & (bsize - 1);
    ctx->count += len;

    if ((index + len) < bsize)
        goto store;

    /* process one stored block */
    if (index) {
        memcpy(ctx->buf + index, data, bsize - index);
        ret = crypt_s390_kimd(ctx->func, ctx->state, ctx->buf, bsize);
        BUG_ON(ret != bsize);
        data += bsize - index;
        len -= bsize - index;
        index = 0;
    }

    /* process as many blocks as possible */
    if (len >= bsize) {
        ret = crypt_s390_kimd(ctx->func, ctx->state, data,
                      len & ~(bsize - 1));
        BUG_ON(ret != (len & ~(bsize - 1)));
        data += ret;
        len -= ret;
    }
store:
    if (len)
        memcpy(ctx->buf + index , data, len);

    return 0;
}
EXPORT_SYMBOL_GPL(s390_sha_update);

int s390_sha_final(struct shash_desc *desc, u8 *out)
{
    struct s390_sha_ctx *ctx = shash_desc_ctx(desc);
    unsigned int bsize = crypto_shash_blocksize(desc->tfm);
    u64 bits;
    unsigned int index, end, plen;
    int ret;

    /* SHA-512 uses 128 bit padding length */
    plen = (bsize > SHA256_BLOCK_SIZE) ? 16 : 8;

    /* must perform manual padding */
    index = ctx->count & (bsize - 1);
    end = (index < bsize - plen) ? bsize : (2 * bsize);

    /* start pad with 1 */
    ctx->buf[index] = 0x80;
    index++;

    /* pad with zeros */
    memset(ctx->buf + index, 0x00, end - index - 8);

    /*
     * Append message length. Well, SHA-512 wants a 128 bit length value,
     * nevertheless we use u64, should be enough for now...
     */
    bits = ctx->count * 8;
    memcpy(ctx->buf + end - 8, &bits, sizeof(bits));

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

    /* copy digest to out */
    memcpy(out, ctx->state, crypto_shash_digestsize(desc->tfm));
    /* wipe context */
    memset(ctx, 0, sizeof *ctx);

    return 0;
}
EXPORT_SYMBOL_GPL(s390_sha_final);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("s390 SHA cipher common functions");