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sha_common.c

/*
 * Cryptographic API.
 *
 * s390 generic implementation of the SHA Secure Hash Algorithms.
 *
 * Copyright IBM Corp. 2007
 * Author(s): Jan Glauber (jang@de.ibm.com)
 *
 * 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 <linux/crypto.h>
#include "sha.h"
#include "crypt_s390.h"

void s390_sha_update(struct crypto_tfm *tfm, const u8 *data, unsigned int len)
{
      struct s390_sha_ctx *ctx = crypto_tfm_ctx(tfm);
      unsigned int bsize = crypto_tfm_alg_blocksize(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;
      }

      /* 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);
}
EXPORT_SYMBOL_GPL(s390_sha_update);

void s390_sha_final(struct crypto_tfm *tfm, u8 *out)
{
      struct s390_sha_ctx *ctx = crypto_tfm_ctx(tfm);
      unsigned int bsize = crypto_tfm_alg_blocksize(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 lenght 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_hash_digestsize(crypto_hash_cast(tfm)));
      /* wipe context */
      memset(ctx, 0, sizeof *ctx);
}
EXPORT_SYMBOL_GPL(s390_sha_final);

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

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