arch/s390/crypto/sha_common.c

   1 /*
   2  * Cryptographic API.
   3  *
   4  * s390 generic implementation of the SHA Secure Hash Algorithms.
   5  *
   6  * Copyright IBM Corp. 2007
   7  * Author(s): Jan Glauber (jang@de.ibm.com)
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the Free
  11  * Software Foundation; either version 2 of the License, or (at your option)
  12  * any later version.
  13  *
  14  */
  15
  16 #include <crypto/internal/hash.h>
  17 #include <linux/module.h>
  18 #include "sha.h"
  19 #include "crypt_s390.h"
  20
  21 int s390_sha_update(struct shash_desc *desc, const u8 *data, unsigned int len)
  22 {
  23         struct s390_sha_ctx *ctx = shash_desc_ctx(desc);
  24         unsigned int bsize = crypto_shash_blocksize(desc->tfm);
  25         unsigned int index;
  26         int ret;
  27
  28         /* how much is already in the buffer? */
  29         index = ctx->count & (bsize - 1);
  30         ctx->count += len;
  31
  32         if ((index + len) < bsize)
  33                 goto store;
  34
  35         /* process one stored block */
  36         if (index) {
  37                 memcpy(ctx->buf + index, data, bsize - index);
  38                 ret = crypt_s390_kimd(ctx->func, ctx->state, ctx->buf, bsize);
  39                 BUG_ON(ret != bsize);
  40                 data += bsize - index;
  41                 len -= bsize - index;
  42                 index = 0;
  43         }
  44
  45         /* process as many blocks as possible */
  46         if (len >= bsize) {
  47                 ret = crypt_s390_kimd(ctx->func, ctx->state, data,
  48                                       len & ~(bsize - 1));
  49                 BUG_ON(ret != (len & ~(bsize - 1)));
  50                 data += ret;
  51                 len -= ret;
  52         }
  53 store:
  54         if (len)
  55                 memcpy(ctx->buf + index , data, len);
  56
  57         return 0;
  58 }
  59 EXPORT_SYMBOL_GPL(s390_sha_update);
  60
  61 int s390_sha_final(struct shash_desc *desc, u8 *out)
  62 {
  63         struct s390_sha_ctx *ctx = shash_desc_ctx(desc);
  64         unsigned int bsize = crypto_shash_blocksize(desc->tfm);
  65         u64 bits;
  66         unsigned int index, end, plen;
  67         int ret;
  68
  69         /* SHA-512 uses 128 bit padding length */
  70         plen = (bsize > SHA256_BLOCK_SIZE) ? 16 : 8;
  71
  72         /* must perform manual padding */
  73         index = ctx->count & (bsize - 1);
  74         end = (index < bsize - plen) ? bsize : (2 * bsize);
  75
  76         /* start pad with 1 */
  77         ctx->buf[index] = 0x80;
  78         index++;
  79
  80         /* pad with zeros */
  81         memset(ctx->buf + index, 0x00, end - index - 8);
  82
  83         /*
  84          * Append message length. Well, SHA-512 wants a 128 bit length value,
  85          * nevertheless we use u64, should be enough for now...
  86          */
  87         bits = ctx->count * 8;
  88         memcpy(ctx->buf + end - 8, &bits, sizeof(bits));
  89
  90         ret = crypt_s390_kimd(ctx->func, ctx->state, ctx->buf, end);
  91         BUG_ON(ret != end);
  92
  93         /* copy digest to out */
  94         memcpy(out, ctx->state, crypto_shash_digestsize(desc->tfm));
  95         /* wipe context */
  96         memset(ctx, 0, sizeof *ctx);
  97
  98         return 0;
  99 }
 100 EXPORT_SYMBOL_GPL(s390_sha_final);
 101
 102 MODULE_LICENSE("GPL");
 103 MODULE_DESCRIPTION("s390 SHA cipher common functions");