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
  21 static void init(struct crypto_tfm *tfm)
  22 {
  23         tfm->__crt_alg->cra_digest.dia_init(crypto_tfm_ctx(tfm));
  24 }
  25
  26 static 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
  50                                                 (crypto_tfm_ctx(tfm), p,
  51                                                  bytes);
  52                                 p += bytes;
  53                                 bytes_from_page -= bytes;
  54                                 l -= bytes;
  55                         }
  56                         tfm->__crt_alg->cra_digest.dia_update
  57                                         (crypto_tfm_ctx(tfm), p,
  58                                          bytes_from_page);
  59                         crypto_kunmap(src, 0);
  60                         crypto_yield(tfm);
  61                         offset = 0;
  62                         pg++;
  63                         l -= bytes_from_page;
  64                 } while (l > 0);
  65         }
  66 }
  67
  68 static void final(struct crypto_tfm *tfm, u8 *out)
  69 {
  70         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  71         if (unlikely((unsigned long)out & alignmask)) {
  72                 unsigned int size = crypto_tfm_alg_digestsize(tfm);
  73                 u8 buffer[size + alignmask];
  74                 u8 *dst = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  75                 tfm->__crt_alg->cra_digest.dia_final(crypto_tfm_ctx(tfm), dst);
  76                 memcpy(out, dst, size);
  77         } else
  78                 tfm->__crt_alg->cra_digest.dia_final(crypto_tfm_ctx(tfm), out);
  79 }
  80
  81 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
  82 {
  83         u32 flags;
  84         if (tfm->__crt_alg->cra_digest.dia_setkey == NULL)
  85                 return -ENOSYS;
  86         return tfm->__crt_alg->cra_digest.dia_setkey(crypto_tfm_ctx(tfm),
  87                                                      key, keylen, &flags);
  88 }
  89
  90 static void digest(struct crypto_tfm *tfm,
  91                    struct scatterlist *sg, unsigned int nsg, u8 *out)
  92 {
  93         init(tfm);
  94         update(tfm, sg, nsg);
  95         final(tfm, out);
  96 }
  97
  98 int crypto_init_digest_flags(struct crypto_tfm *tfm, u32 flags)
  99 {
 100         return flags ? -EINVAL : 0;
 101 }
 102
 103 int crypto_init_digest_ops(struct crypto_tfm *tfm)
 104 {
 105         struct digest_tfm *ops = &tfm->crt_digest;
 106
 107         ops->dit_init   = init;
 108         ops->dit_update = update;
 109         ops->dit_final  = final;
 110         ops->dit_digest = digest;
 111         ops->dit_setkey = setkey;
 112
 113         return crypto_alloc_hmac_block(tfm);
 114 }
 115
 116 void crypto_exit_digest_ops(struct crypto_tfm *tfm)
 117 {
 118         crypto_free_hmac_block(tfm);
 119 }