arch/s390/crypto/sha256_s390.c

   1 /*
   2  * Cryptographic API.
   3  *
   4  * s390 implementation of the SHA256 Secure Hash Algorithm.
   5  *
   6  * s390 Version:
   7  *   Copyright IBM Corp. 2005,2007
   8  *   Author(s): Jan Glauber (jang@de.ibm.com)
   9  *
  10  * Derived from "crypto/sha256_generic.c"
  11  * and "arch/s390/crypto/sha1_s390.c"
  12  *
  13  * This program is free software; you can redistribute it and/or modify it
  14  * under the terms of the GNU General Public License as published by the Free
  15  * Software Foundation; either version 2 of the License, or (at your option)
  16  * any later version.
  17  *
  18  */
  19 #include <linux/init.h>
  20 #include <linux/module.h>
  21 #include <linux/crypto.h>
  22 #include <crypto/sha.h>
  23
  24 #include "crypt_s390.h"
  25
  26 struct s390_sha256_ctx {
  27         u64 count;              /* message length */
  28         u32 state[8];
  29         u8 buf[2 * SHA256_BLOCK_SIZE];
  30 };
  31
  32 static void sha256_init(struct crypto_tfm *tfm)
  33 {
  34         struct s390_sha256_ctx *sctx = crypto_tfm_ctx(tfm);
  35
  36         sctx->state[0] = SHA256_H0;
  37         sctx->state[1] = SHA256_H1;
  38         sctx->state[2] = SHA256_H2;
  39         sctx->state[3] = SHA256_H3;
  40         sctx->state[4] = SHA256_H4;
  41         sctx->state[5] = SHA256_H5;
  42         sctx->state[6] = SHA256_H6;
  43         sctx->state[7] = SHA256_H7;
  44         sctx->count = 0;
  45 }
  46
  47 static void sha256_update(struct crypto_tfm *tfm, const u8 *data,
  48                           unsigned int len)
  49 {
  50         struct s390_sha256_ctx *sctx = crypto_tfm_ctx(tfm);
  51         unsigned int index;
  52         int ret;
  53
  54         /* how much is already in the buffer? */
  55         index = sctx->count & 0x3f;
  56
  57         sctx->count += len;
  58
  59         if ((index + len) < SHA256_BLOCK_SIZE)
  60                 goto store;
  61
  62         /* process one stored block */
  63         if (index) {
  64                 memcpy(sctx->buf + index, data, SHA256_BLOCK_SIZE - index);
  65                 ret = crypt_s390_kimd(KIMD_SHA_256, sctx->state, sctx->buf,
  66                                       SHA256_BLOCK_SIZE);
  67                 BUG_ON(ret != SHA256_BLOCK_SIZE);
  68                 data += SHA256_BLOCK_SIZE - index;
  69                 len -= SHA256_BLOCK_SIZE - index;
  70         }
  71
  72         /* process as many blocks as possible */
  73         if (len >= SHA256_BLOCK_SIZE) {
  74                 ret = crypt_s390_kimd(KIMD_SHA_256, sctx->state, data,
  75                                       len & ~(SHA256_BLOCK_SIZE - 1));
  76                 BUG_ON(ret != (len & ~(SHA256_BLOCK_SIZE - 1)));
  77                 data += ret;
  78                 len -= ret;
  79         }
  80
  81 store:
  82         /* anything left? */
  83         if (len)
  84                 memcpy(sctx->buf + index , data, len);
  85 }
  86
  87 /* Add padding and return the message digest */
  88 static void sha256_final(struct crypto_tfm *tfm, u8 *out)
  89 {
  90         struct s390_sha256_ctx *sctx = crypto_tfm_ctx(tfm);
  91         u64 bits;
  92         unsigned int index, end;
  93         int ret;
  94
  95         /* must perform manual padding */
  96         index = sctx->count & 0x3f;
  97         end = (index < 56) ? SHA256_BLOCK_SIZE : (2 * SHA256_BLOCK_SIZE);
  98
  99         /* start pad with 1 */
 100         sctx->buf[index] = 0x80;
 101
 102         /* pad with zeros */
 103         index++;
 104         memset(sctx->buf + index, 0x00, end - index - 8);
 105
 106         /* append message length */
 107         bits = sctx->count * 8;
 108         memcpy(sctx->buf + end - 8, &bits, sizeof(bits));
 109
 110         ret = crypt_s390_kimd(KIMD_SHA_256, sctx->state, sctx->buf, end);
 111         BUG_ON(ret != end);
 112
 113         /* copy digest to out */
 114         memcpy(out, sctx->state, SHA256_DIGEST_SIZE);
 115
 116         /* wipe context */
 117         memset(sctx, 0, sizeof *sctx);
 118 }
 119
 120 static struct crypto_alg alg = {
 121         .cra_name       =       "sha256",
 122         .cra_driver_name =      "sha256-s390",
 123         .cra_priority   =       CRYPT_S390_PRIORITY,
 124         .cra_flags      =       CRYPTO_ALG_TYPE_DIGEST,
 125         .cra_blocksize  =       SHA256_BLOCK_SIZE,
 126         .cra_ctxsize    =       sizeof(struct s390_sha256_ctx),
 127         .cra_module     =       THIS_MODULE,
 128         .cra_list       =       LIST_HEAD_INIT(alg.cra_list),
 129         .cra_u          =       { .digest = {
 130         .dia_digestsize =       SHA256_DIGEST_SIZE,
 131         .dia_init       =       sha256_init,
 132         .dia_update     =       sha256_update,
 133         .dia_final      =       sha256_final } }
 134 };
 135
 136 static int init(void)
 137 {
 138         if (!crypt_s390_func_available(KIMD_SHA_256))
 139                 return -EOPNOTSUPP;
 140
 141         return crypto_register_alg(&alg);
 142 }
 143
 144 static void __exit fini(void)
 145 {
 146         crypto_unregister_alg(&alg);
 147 }
 148
 149 module_init(init);
 150 module_exit(fini);
 151
 152 MODULE_ALIAS("sha256");
 153
 154 MODULE_LICENSE("GPL");
 155 MODULE_DESCRIPTION("SHA256 Secure Hash Algorithm");