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                 if (ret != bsize)
  40                         return -EIO;
  41                 data += bsize - index;
  42                 len -= bsize - index;
  43                 index = 0;
  44         }
  45
  46         /* process as many blocks as possible */
  47         if (len >= bsize) {
  48                 ret = crypt_s390_kimd(ctx->func, ctx->state, data,
  49                                       len & ~(bsize - 1));
  50                 if (ret != (len & ~(bsize - 1)))
  51                         return -EIO;
  52                 data += ret;
  53                 len -= ret;
  54         }
  55 store:
  56         if (len)
  57                 memcpy(ctx->buf + index , data, len);
  58
  59         return 0;
  60 }
  61 EXPORT_SYMBOL_GPL(s390_sha_update);
  62
  63 int s390_sha_final(struct shash_desc *desc, u8 *out)
  64 {
  65         struct s390_sha_ctx *ctx = shash_desc_ctx(desc);
  66         unsigned int bsize = crypto_shash_blocksize(desc->tfm);
  67         u64 bits;
  68         unsigned int index, end, plen;
  69         int ret;
  70
  71         /* SHA-512 uses 128 bit padding length */
  72         plen = (bsize > SHA256_BLOCK_SIZE) ? 16 : 8;
  73
  74         /* must perform manual padding */
  75         index = ctx->count & (bsize - 1);
  76         end = (index < bsize - plen) ? bsize : (2 * bsize);
  77
  78         /* start pad with 1 */
  79         ctx->buf[index] = 0x80;
  80         index++;
  81
  82         /* pad with zeros */
  83         memset(ctx->buf + index, 0x00, end - index - 8);
  84
  85         /*
  86          * Append message length. Well, SHA-512 wants a 128 bit length value,
  87          * nevertheless we use u64, should be enough for now...
  88          */
  89         bits = ctx->count * 8;
  90         memcpy(ctx->buf + end - 8, &bits, sizeof(bits));
  91
  92         ret = crypt_s390_kimd(ctx->func, ctx->state, ctx->buf, end);
  93         if (ret != end)
  94                 return -EIO;
  95
  96         /* copy digest to out */
  97         memcpy(out, ctx->state, crypto_shash_digestsize(desc->tfm));
  98         /* wipe context */
  99         memset(ctx, 0, sizeof *ctx);
 100
 101         return 0;
 102 }
 103 EXPORT_SYMBOL_GPL(s390_sha_final);
 104
 105 MODULE_LICENSE("GPL");
 106 MODULE_DESCRIPTION("s390 SHA cipher common functions");