linux/crypto/digest.c
<<
>>
Prefs
   1/*
   2 * Cryptographic API.
   3 *
   4 * Digest operations.
   5 *
   6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
   7 *
   8 * This program is free software; you can redistribute it and/or modify it
   9 * under the terms of the GNU General Public License as published by the Free
  10 * Software Foundation; either version 2 of the License, or (at your option) 
  11 * any later version.
  12 *
  13 */
  14
  15#include <linux/mm.h>
  16#include <linux/errno.h>
  17#include <linux/highmem.h>
  18#include <linux/module.h>
  19#include <linux/scatterlist.h>
  20
  21#include "internal.h"
  22#include "scatterwalk.h"
  23
  24void crypto_digest_init(struct crypto_tfm *tfm)
  25{
  26        struct crypto_hash *hash = crypto_hash_cast(tfm);
  27        struct hash_desc desc = { .tfm = hash, .flags = tfm->crt_flags };
  28
  29        crypto_hash_init(&desc);
  30}
  31EXPORT_SYMBOL_GPL(crypto_digest_init);
  32
  33void crypto_digest_update(struct crypto_tfm *tfm,
  34                          struct scatterlist *sg, unsigned int nsg)
  35{
  36        struct crypto_hash *hash = crypto_hash_cast(tfm);
  37        struct hash_desc desc = { .tfm = hash, .flags = tfm->crt_flags };
  38        unsigned int nbytes = 0;
  39        unsigned int i;
  40
  41        for (i = 0; i < nsg; i++)
  42                nbytes += sg[i].length;
  43
  44        crypto_hash_update(&desc, sg, nbytes);
  45}
  46EXPORT_SYMBOL_GPL(crypto_digest_update);
  47
  48void crypto_digest_final(struct crypto_tfm *tfm, u8 *out)
  49{
  50        struct crypto_hash *hash = crypto_hash_cast(tfm);
  51        struct hash_desc desc = { .tfm = hash, .flags = tfm->crt_flags };
  52
  53        crypto_hash_final(&desc, out);
  54}
  55EXPORT_SYMBOL_GPL(crypto_digest_final);
  56
  57void crypto_digest_digest(struct crypto_tfm *tfm,
  58                          struct scatterlist *sg, unsigned int nsg, u8 *out)
  59{
  60        struct crypto_hash *hash = crypto_hash_cast(tfm);
  61        struct hash_desc desc = { .tfm = hash, .flags = tfm->crt_flags };
  62        unsigned int nbytes = 0;
  63        unsigned int i;
  64
  65        for (i = 0; i < nsg; i++)
  66                nbytes += sg[i].length;
  67
  68        crypto_hash_digest(&desc, sg, nbytes, out);
  69}
  70EXPORT_SYMBOL_GPL(crypto_digest_digest);
  71
  72static int init(struct hash_desc *desc)
  73{
  74        struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
  75
  76        tfm->__crt_alg->cra_digest.dia_init(tfm);
  77        return 0;
  78}
  79
  80static int update(struct hash_desc *desc,
  81                  struct scatterlist *sg, unsigned int nbytes)
  82{
  83        struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
  84        unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
  85
  86        if (!nbytes)
  87                return 0;
  88
  89        for (;;) {
  90                struct page *pg = sg->page;
  91                unsigned int offset = sg->offset;
  92                unsigned int l = sg->length;
  93
  94                if (unlikely(l > nbytes))
  95                        l = nbytes;
  96                nbytes -= l;
  97
  98                do {
  99                        unsigned int bytes_from_page = min(l, ((unsigned int)
 100                                                           (PAGE_SIZE)) - 
 101                                                           offset);
 102                        char *src = crypto_kmap(pg, 0);
 103                        char *p = src + offset;
 104
 105                        if (unlikely(offset & alignmask)) {
 106                                unsigned int bytes =
 107                                        alignmask + 1 - (offset & alignmask);
 108                                bytes = min(bytes, bytes_from_page);
 109                                tfm->__crt_alg->cra_digest.dia_update(tfm, p,
 110                                                                      bytes);
 111                                p += bytes;
 112                                bytes_from_page -= bytes;
 113                                l -= bytes;
 114                        }
 115                        tfm->__crt_alg->cra_digest.dia_update(tfm, p,
 116                                                              bytes_from_page);
 117                        crypto_kunmap(src, 0);
 118                        crypto_yield(desc->flags);
 119                        offset = 0;
 120                        pg++;
 121                        l -= bytes_from_page;
 122                } while (l > 0);
 123
 124                if (!nbytes)
 125                        break;
 126                sg = sg_next(sg);
 127        }
 128
 129        return 0;
 130}
 131
 132static int final(struct hash_desc *desc, u8 *out)
 133{
 134        struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
 135        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
 136        struct digest_alg *digest = &tfm->__crt_alg->cra_digest;
 137
 138        if (unlikely((unsigned long)out & alignmask)) {
 139                unsigned long align = alignmask + 1;
 140                unsigned long addr = (unsigned long)crypto_tfm_ctx(tfm);
 141                u8 *dst = (u8 *)ALIGN(addr, align) +
 142                          ALIGN(tfm->__crt_alg->cra_ctxsize, align);
 143
 144                digest->dia_final(tfm, dst);
 145                memcpy(out, dst, digest->dia_digestsize);
 146        } else
 147                digest->dia_final(tfm, out);
 148
 149        return 0;
 150}
 151
 152static int nosetkey(struct crypto_hash *tfm, const u8 *key, unsigned int keylen)
 153{
 154        crypto_hash_clear_flags(tfm, CRYPTO_TFM_RES_MASK);
 155        return -ENOSYS;
 156}
 157
 158static int setkey(struct crypto_hash *hash, const u8 *key, unsigned int keylen)
 159{
 160        struct crypto_tfm *tfm = crypto_hash_tfm(hash);
 161
 162        crypto_hash_clear_flags(hash, CRYPTO_TFM_RES_MASK);
 163        return tfm->__crt_alg->cra_digest.dia_setkey(tfm, key, keylen);
 164}
 165
 166static int digest(struct hash_desc *desc,
 167                  struct scatterlist *sg, unsigned int nbytes, u8 *out)
 168{
 169        init(desc);
 170        update(desc, sg, nbytes);
 171        return final(desc, out);
 172}
 173
 174int crypto_init_digest_flags(struct crypto_tfm *tfm, u32 flags)
 175{
 176        return flags ? -EINVAL : 0;
 177}
 178
 179int crypto_init_digest_ops(struct crypto_tfm *tfm)
 180{
 181        struct hash_tfm *ops = &tfm->crt_hash;
 182        struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
 183
 184        if (dalg->dia_digestsize > crypto_tfm_alg_blocksize(tfm))
 185                return -EINVAL;
 186        
 187        ops->init       = init;
 188        ops->update     = update;
 189        ops->final      = final;
 190        ops->digest     = digest;
 191        ops->setkey     = dalg->dia_setkey ? setkey : nosetkey;
 192        ops->digestsize = dalg->dia_digestsize;
 193        
 194        return 0;
 195}
 196
 197void crypto_exit_digest_ops(struct crypto_tfm *tfm)
 198{
 199}
 200
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.