LXR linux/crypto/digest.c

   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#include <linux/crypto.h>
  15#include <linux/mm.h>
  16#include <linux/errno.h>
  17#include <linux/highmem.h>
  18#include <asm/scatterlist.h>
  19#include "internal.h"
  20
  21static void init(struct crypto_tfm *tfm)
  22{
  23        tfm->__crt_alg->cra_digest.dia_init(tfm);
  24}
  25
  26static void update(struct crypto_tfm *tfm,
  27                   struct scatterlist *sg, unsigned int nsg)
  28{
  29        unsigned int i;
  30        unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
  31
  32        for (i = 0; i < nsg; i++) {
  33
  34                struct page *pg = sg[i].page;
  35                unsigned int offset = sg[i].offset;
  36                unsigned int l = sg[i].length;
  37
  38                do {
  39                        unsigned int bytes_from_page = min(l, ((unsigned int)
  40                                                           (PAGE_SIZE)) - 
  41                                                           offset);
  42                        char *src = crypto_kmap(pg, 0);
  43                        char *p = src + offset;
  44
  45                        if (unlikely(offset & alignmask)) {
  46                                unsigned int bytes =
  47                                        alignmask + 1 - (offset & alignmask);
  48                                bytes = min(bytes, bytes_from_page);
  49                                tfm->__crt_alg->cra_digest.dia_update(tfm, p,
  50                                                                      bytes);
  51                                p += bytes;
  52                                bytes_from_page -= bytes;
  53                                l -= bytes;
  54                        }
  55                        tfm->__crt_alg->cra_digest.dia_update(tfm, p,
  56                                                              bytes_from_page);
  57                        crypto_kunmap(src, 0);
  58                        crypto_yield(tfm);
  59                        offset = 0;
  60                        pg++;
  61                        l -= bytes_from_page;
  62                } while (l > 0);
  63        }
  64}
  65
  66static void final(struct crypto_tfm *tfm, u8 *out)
  67{
  68        unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  69        if (unlikely((unsigned long)out & alignmask)) {
  70                unsigned int size = crypto_tfm_alg_digestsize(tfm);
  71                u8 buffer[size + alignmask];
  72                u8 *dst = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  73                tfm->__crt_alg->cra_digest.dia_final(tfm, dst);
  74                memcpy(out, dst, size);
  75        } else
  76                tfm->__crt_alg->cra_digest.dia_final(tfm, out);
  77}
  78
  79static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
  80{
  81        u32 flags;
  82        if (tfm->__crt_alg->cra_digest.dia_setkey == NULL)
  83                return -ENOSYS;
  84        return tfm->__crt_alg->cra_digest.dia_setkey(tfm, key, keylen, &flags);
  85}
  86
  87static void digest(struct crypto_tfm *tfm,
  88                   struct scatterlist *sg, unsigned int nsg, u8 *out)
  89{
  90        init(tfm);
  91        update(tfm, sg, nsg);
  92        final(tfm, out);
  93}
  94
  95int crypto_init_digest_flags(struct crypto_tfm *tfm, u32 flags)
  96{
  97        return flags ? -EINVAL : 0;
  98}
  99
 100int crypto_init_digest_ops(struct crypto_tfm *tfm)
 101{
 102        struct digest_tfm *ops = &tfm->crt_digest;
 103        
 104        ops->dit_init   = init;
 105        ops->dit_update = update;
 106        ops->dit_final  = final;
 107        ops->dit_digest = digest;
 108        ops->dit_setkey = setkey;
 109        
 110        return crypto_alloc_hmac_block(tfm);
 111}
 112
 113void crypto_exit_digest_ops(struct crypto_tfm *tfm)
 114{
 115        crypto_free_hmac_block(tfm);
 116}
 117