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 <asm/cpacf.h>
  19 #include "sha.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, n;
  26
  27         /* how much is already in the buffer? */
  28         index = ctx->count & (bsize - 1);
  29         ctx->count += len;
  30
  31         if ((index + len) < bsize)
  32                 goto store;
  33
  34         /* process one stored block */
  35         if (index) {
  36                 memcpy(ctx->buf + index, data, bsize - index);
  37                 cpacf_kimd(ctx->func, ctx->state, ctx->buf, bsize);
  38                 data += bsize - index;
  39                 len -= bsize - index;
  40                 index = 0;
  41         }
  42
  43         /* process as many blocks as possible */
  44         if (len >= bsize) {
  45                 n = len & ~(bsize - 1);
  46                 cpacf_kimd(ctx->func, ctx->state, data, n);
  47                 data += n;
  48                 len -= n;
  49         }
  50 store:
  51         if (len)
  52                 memcpy(ctx->buf + index , data, len);
  53
  54         return 0;
  55 }
  56 EXPORT_SYMBOL_GPL(s390_sha_update);
  57
  58 int s390_sha_final(struct shash_desc *desc, u8 *out)
  59 {
  60         struct s390_sha_ctx *ctx = shash_desc_ctx(desc);
  61         unsigned int bsize = crypto_shash_blocksize(desc->tfm);
  62         u64 bits;
  63         unsigned int index, end, plen;
  64
  65         /* SHA-512 uses 128 bit padding length */
  66         plen = (bsize > SHA256_BLOCK_SIZE) ? 16 : 8;
  67
  68         /* must perform manual padding */
  69         index = ctx->count & (bsize - 1);
  70         end = (index < bsize - plen) ? bsize : (2 * bsize);
  71
  72         /* start pad with 1 */
  73         ctx->buf[index] = 0x80;
  74         index++;
  75
  76         /* pad with zeros */
  77         memset(ctx->buf + index, 0x00, end - index - 8);
  78
  79         /*
  80          * Append message length. Well, SHA-512 wants a 128 bit length value,
  81          * nevertheless we use u64, should be enough for now...
  82          */
  83         bits = ctx->count * 8;
  84         memcpy(ctx->buf + end - 8, &bits, sizeof(bits));
  85         cpacf_kimd(ctx->func, ctx->state, ctx->buf, end);
  86
  87         /* copy digest to out */
  88         memcpy(out, ctx->state, crypto_shash_digestsize(desc->tfm));
  89         /* wipe context */
  90         memset(ctx, 0, sizeof *ctx);
  91
  92         return 0;
  93 }
  94 EXPORT_SYMBOL_GPL(s390_sha_final);
  95
  96 MODULE_LICENSE("GPL");
  97 MODULE_DESCRIPTION("s390 SHA cipher common functions");