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(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(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->crt_flags);
  59                         offset = 0;
  60                         pg++;
  61                         l -= bytes_from_page;
  62                 } while (l > 0);
  63         }
  64 }
  65
  66 static void final(struct crypto_tfm *tfm, u8 *out)
  67 {
  68         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
  69         struct digest_alg *digest = &tfm->__crt_alg->cra_digest;
  70
  71         if (unlikely((unsigned long)out & alignmask)) {
  72                 unsigned long align = alignmask + 1;
  73                 unsigned long addr = (unsigned long)crypto_tfm_ctx(tfm);
  74                 u8 *dst = (u8 *)ALIGN(addr, align) +
  75                           ALIGN(tfm->__crt_alg->cra_ctxsize, align);
  76
  77                 digest->dia_final(tfm, dst);
  78                 memcpy(out, dst, digest->dia_digestsize);
  79         } else
  80                 digest->dia_final(tfm, out);
  81 }
  82
  83 static int nosetkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
  84 {
  85         tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
  86         return -ENOSYS;
  87 }
  88
  89 static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
  90 {
  91         tfm->crt_flags &= ~CRYPTO_TFM_RES_MASK;
  92         return tfm->__crt_alg->cra_digest.dia_setkey(tfm, key, keylen);
  93 }
  94
  95 static void digest(struct crypto_tfm *tfm,
  96                    struct scatterlist *sg, unsigned int nsg, u8 *out)
  97 {
  98         init(tfm);
  99         update(tfm, sg, nsg);
 100         final(tfm, out);
 101 }
 102
 103 int crypto_init_digest_flags(struct crypto_tfm *tfm, u32 flags)
 104 {
 105         return flags ? -EINVAL : 0;
 106 }
 107
 108 int crypto_init_digest_ops(struct crypto_tfm *tfm)
 109 {
 110         struct digest_tfm *ops = &tfm->crt_digest;
 111         struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
 112
 113         ops->dit_init   = init;
 114         ops->dit_update = update;
 115         ops->dit_final  = final;
 116         ops->dit_digest = digest;
 117         ops->dit_setkey = dalg->dia_setkey ? setkey : nosetkey;
 118
 119         return crypto_alloc_hmac_block(tfm);
 120 }
 121
 122 void crypto_exit_digest_ops(struct crypto_tfm *tfm)
 123 {
 124         crypto_free_hmac_block(tfm);
 125 }