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 (C) 2005 IBM Deutschland GmbH, IBM Corporation
   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;
  30         u32 state[8];
  31         u8 buf[2 * SHA256_BLOCK_SIZE];
  32 };
  33
  34 static void sha256_init(void *ctx)
  35 {
  36         struct s390_sha256_ctx *sctx = ctx;
  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         memset(sctx->buf, 0, sizeof(sctx->buf));
  48 }
  49
  50 static void sha256_update(void *ctx, const u8 *data, unsigned int len)
  51 {
  52         struct s390_sha256_ctx *sctx = ctx;
  53         unsigned int index;
  54
  55         /* how much is already in the buffer? */
  56         index = sctx->count / 8 & 0x3f;
  57
  58         /* update message bit length */
  59         sctx->count += len * 8;
  60
  61         /* process one block */
  62         if ((index + len) >= SHA256_BLOCK_SIZE) {
  63                 memcpy(sctx->buf + index, data, SHA256_BLOCK_SIZE - index);
  64                 crypt_s390_kimd(KIMD_SHA_256, sctx->state, sctx->buf,
  65                                 SHA256_BLOCK_SIZE);
  66                 data += SHA256_BLOCK_SIZE - index;
  67                 len -= SHA256_BLOCK_SIZE - index;
  68         }
  69
  70         /* anything left? */
  71         if (len)
  72                 memcpy(sctx->buf + index , data, len);
  73 }
  74
  75 static void pad_message(struct s390_sha256_ctx* sctx)
  76 {
  77         int index, end;
  78
  79         index = sctx->count / 8 & 0x3f;
  80         end = index < 56 ? SHA256_BLOCK_SIZE : 2 * SHA256_BLOCK_SIZE;
  81
  82         /* start pad with 1 */
  83         sctx->buf[index] = 0x80;
  84
  85         /* pad with zeros */
  86         index++;
  87         memset(sctx->buf + index, 0x00, end - index - 8);
  88
  89         /* append message length */
  90         memcpy(sctx->buf + end - 8, &sctx->count, sizeof sctx->count);
  91
  92         sctx->count = end * 8;
  93 }
  94
  95 /* Add padding and return the message digest */
  96 static void sha256_final(void* ctx, u8 *out)
  97 {
  98         struct s390_sha256_ctx *sctx = ctx;
  99
 100         /* must perform manual padding */
 101         pad_message(sctx);
 102
 103         crypt_s390_kimd(KIMD_SHA_256, sctx->state, sctx->buf,
 104                         sctx->count / 8);
 105
 106         /* copy digest to out */
 107         memcpy(out, sctx->state, SHA256_DIGEST_SIZE);
 108
 109         /* wipe context */
 110         memset(sctx, 0, sizeof *sctx);
 111 }
 112
 113 static struct crypto_alg alg = {
 114         .cra_name       =       "sha256",
 115         .cra_flags      =       CRYPTO_ALG_TYPE_DIGEST,
 116         .cra_blocksize  =       SHA256_BLOCK_SIZE,
 117         .cra_ctxsize    =       sizeof(struct s390_sha256_ctx),
 118         .cra_module     =       THIS_MODULE,
 119         .cra_list       =       LIST_HEAD_INIT(alg.cra_list),
 120         .cra_u          =       { .digest = {
 121         .dia_digestsize =       SHA256_DIGEST_SIZE,
 122         .dia_init       =       sha256_init,
 123         .dia_update     =       sha256_update,
 124         .dia_final      =       sha256_final } }
 125 };
 126
 127 static int init(void)
 128 {
 129         int ret;
 130
 131         if (!crypt_s390_func_available(KIMD_SHA_256))
 132                 return -ENOSYS;
 133
 134         ret = crypto_register_alg(&alg);
 135         if (ret != 0)
 136                 printk(KERN_INFO "crypt_s390: sha256_s390 couldn't be loaded.");
 137         return ret;
 138 }
 139
 140 static void __exit fini(void)
 141 {
 142         crypto_unregister_alg(&alg);
 143 }
 144
 145 module_init(init);
 146 module_exit(fini);
 147
 148 MODULE_ALIAS("sha256");
 149
 150 MODULE_LICENSE("GPL");
 151 MODULE_DESCRIPTION("SHA256 Secure Hash Algorithm");