LXR linux/arch/s390/crypto/sha256

   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
  26struct s390_sha256_ctx {
  27        u64 count;              /* message length */
  28        u32 state[8];
  29        u8 buf[2 * SHA256_BLOCK_SIZE];
  30};
  31
  32static 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
  47static 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
  81store:
  82        /* anything left? */
  83        if (len)
  84                memcpy(sctx->buf + index , data, len);
  85}
  86
  87/* Add padding and return the message digest */
  88static 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
 120static 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
 136static 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
 144static void __exit fini(void)
 145{
 146        crypto_unregister_alg(&alg);
 147}
 148
 149module_init(init);
 150module_exit(fini);
 151
 152MODULE_ALIAS("sha256");
 153
 154MODULE_LICENSE("GPL");
 155MODULE_DESCRIPTION("SHA256 Secure Hash Algorithm");
 156