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.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
  23 #include "crypt_s390.h"
  24
  25 #define SHA256_DIGEST_SIZE      32
  26 #define SHA256_BLOCK_SIZE       64
  27
  28 struct s390_sha256_ctx {
  29         u64 count;              /* message length */
  30         u32 state[8];
  31         u8 buf[2 * SHA256_BLOCK_SIZE];
  32 };
  33
  34 static void sha256_init(struct crypto_tfm *tfm)
  35 {
  36         struct s390_sha256_ctx *sctx = crypto_tfm_ctx(tfm);
  37
  38         sctx->state[0] = 0x6a09e667;
  39         sctx->state[1] = 0xbb67ae85;
  40         sctx->state[2] = 0x3c6ef372;
  41         sctx->state[3] = 0xa54ff53a;
  42         sctx->state[4] = 0x510e527f;
  43         sctx->state[5] = 0x9b05688c;
  44         sctx->state[6] = 0x1f83d9ab;
  45         sctx->state[7] = 0x5be0cd19;
  46         sctx->count = 0;
  47 }
  48
  49 static void sha256_update(struct crypto_tfm *tfm, const u8 *data,
  50                           unsigned int len)
  51 {
  52         struct s390_sha256_ctx *sctx = crypto_tfm_ctx(tfm);
  53         unsigned int index;
  54         int ret;
  55
  56         /* how much is already in the buffer? */
  57         index = sctx->count & 0x3f;
  58
  59         sctx->count += len;
  60
  61         if ((index + len) < SHA256_BLOCK_SIZE)
  62                 goto store;
  63
  64         /* process one stored block */
  65         if (index) {
  66                 memcpy(sctx->buf + index, data, SHA256_BLOCK_SIZE - index);
  67                 ret = crypt_s390_kimd(KIMD_SHA_256, sctx->state, sctx->buf,
  68                                       SHA256_BLOCK_SIZE);
  69                 BUG_ON(ret != SHA256_BLOCK_SIZE);
  70                 data += SHA256_BLOCK_SIZE - index;
  71                 len -= SHA256_BLOCK_SIZE - index;
  72         }
  73
  74         /* process as many blocks as possible */
  75         if (len >= SHA256_BLOCK_SIZE) {
  76                 ret = crypt_s390_kimd(KIMD_SHA_256, sctx->state, data,
  77                                       len & ~(SHA256_BLOCK_SIZE - 1));
  78                 BUG_ON(ret != (len & ~(SHA256_BLOCK_SIZE - 1)));
  79                 data += ret;
  80                 len -= ret;
  81         }
  82
  83 store:
  84         /* anything left? */
  85         if (len)
  86                 memcpy(sctx->buf + index , data, len);
  87 }
  88
  89 /* Add padding and return the message digest */
  90 static void sha256_final(struct crypto_tfm *tfm, u8 *out)
  91 {
  92         struct s390_sha256_ctx *sctx = crypto_tfm_ctx(tfm);
  93         u64 bits;
  94         unsigned int index, end;
  95         int ret;
  96
  97         /* must perform manual padding */
  98         index = sctx->count & 0x3f;
  99         end = (index < 56) ? SHA256_BLOCK_SIZE : (2 * SHA256_BLOCK_SIZE);
 100
 101         /* start pad with 1 */
 102         sctx->buf[index] = 0x80;
 103
 104         /* pad with zeros */
 105         index++;
 106         memset(sctx->buf + index, 0x00, end - index - 8);
 107
 108         /* append message length */
 109         bits = sctx->count * 8;
 110         memcpy(sctx->buf + end - 8, &bits, sizeof(bits));
 111
 112         ret = crypt_s390_kimd(KIMD_SHA_256, sctx->state, sctx->buf, end);
 113         BUG_ON(ret != end);
 114
 115         /* copy digest to out */
 116         memcpy(out, sctx->state, SHA256_DIGEST_SIZE);
 117
 118         /* wipe context */
 119         memset(sctx, 0, sizeof *sctx);
 120 }
 121
 122 static struct crypto_alg alg = {
 123         .cra_name       =       "sha256",
 124         .cra_driver_name =      "sha256-s390",
 125         .cra_priority   =       CRYPT_S390_PRIORITY,
 126         .cra_flags      =       CRYPTO_ALG_TYPE_DIGEST,
 127         .cra_blocksize  =       SHA256_BLOCK_SIZE,
 128         .cra_ctxsize    =       sizeof(struct s390_sha256_ctx),
 129         .cra_module     =       THIS_MODULE,
 130         .cra_list       =       LIST_HEAD_INIT(alg.cra_list),
 131         .cra_u          =       { .digest = {
 132         .dia_digestsize =       SHA256_DIGEST_SIZE,
 133         .dia_init       =       sha256_init,
 134         .dia_update     =       sha256_update,
 135         .dia_final      =       sha256_final } }
 136 };
 137
 138 static int init(void)
 139 {
 140         if (!crypt_s390_func_available(KIMD_SHA_256))
 141                 return -EOPNOTSUPP;
 142
 143         return crypto_register_alg(&alg);
 144 }
 145
 146 static void __exit fini(void)
 147 {
 148         crypto_unregister_alg(&alg);
 149 }
 150
 151 module_init(init);
 152 module_exit(fini);
 153
 154 MODULE_ALIAS("sha256");
 155
 156 MODULE_LICENSE("GPL");
 157 MODULE_DESCRIPTION("SHA256 Secure Hash Algorithm");