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 <linux/crypto.h>
  17 #include "sha.h"
  18 #include "crypt_s390.h"
  19
  20 void s390_sha_update(struct crypto_tfm *tfm, const u8 *data, unsigned int len)
  21 {
  22         struct s390_sha_ctx *ctx = crypto_tfm_ctx(tfm);
  23         unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
  24         unsigned int index;
  25         int ret;
  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                 ret = crypt_s390_kimd(ctx->func, ctx->state, ctx->buf, bsize);
  38                 BUG_ON(ret != bsize);
  39                 data += bsize - index;
  40                 len -= bsize - index;
  41         }
  42
  43         /* process as many blocks as possible */
  44         if (len >= bsize) {
  45                 ret = crypt_s390_kimd(ctx->func, ctx->state, data,
  46                                       len & ~(bsize - 1));
  47                 BUG_ON(ret != (len & ~(bsize - 1)));
  48                 data += ret;
  49                 len -= ret;
  50         }
  51 store:
  52         if (len)
  53                 memcpy(ctx->buf + index , data, len);
  54 }
  55 EXPORT_SYMBOL_GPL(s390_sha_update);
  56
  57 void s390_sha_final(struct crypto_tfm *tfm, u8 *out)
  58 {
  59         struct s390_sha_ctx *ctx = crypto_tfm_ctx(tfm);
  60         unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
  61         u64 bits;
  62         unsigned int index, end, plen;
  63         int ret;
  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 lenght 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
  86         ret = crypt_s390_kimd(ctx->func, ctx->state, ctx->buf, end);
  87         BUG_ON(ret != end);
  88
  89         /* copy digest to out */
  90         memcpy(out, ctx->state, crypto_hash_digestsize(crypto_hash_cast(tfm)));
  91         /* wipe context */
  92         memset(ctx, 0, sizeof *ctx);
  93 }
  94 EXPORT_SYMBOL_GPL(s390_sha_final);
  95
  96 MODULE_LICENSE("GPL");
  97 MODULE_DESCRIPTION("s390 SHA cipher common functions");