crypto/hash.c

   1 /*
   2  * Cryptographic Hash operations.
   3  *
   4  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; either version 2 of the License, or (at your option)
   9  * any later version.
  10  */
  11
  12 #include <linux/errno.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/seq_file.h>
  16
  17 #include "internal.h"
  18
  19 static unsigned int crypto_hash_ctxsize(struct crypto_alg *alg, u32 type,
  20                                         u32 mask)
  21 {
  22         return alg->cra_ctxsize;
  23 }
  24
  25 static int hash_setkey_unaligned(struct crypto_hash *crt, const u8 *key,
  26                                  unsigned int keylen)
  27 {
  28         struct crypto_tfm *tfm = crypto_hash_tfm(crt);
  29         struct hash_alg *alg = &tfm->__crt_alg->cra_hash;
  30         unsigned long alignmask = crypto_hash_alignmask(crt);
  31         int ret;
  32         u8 *buffer, *alignbuffer;
  33         unsigned long absize;
  34
  35         absize = keylen + alignmask;
  36         buffer = kmalloc(absize, GFP_ATOMIC);
  37         if (!buffer)
  38                 return -ENOMEM;
  39
  40         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  41         memcpy(alignbuffer, key, keylen);
  42         ret = alg->setkey(crt, alignbuffer, keylen);
  43         memset(alignbuffer, 0, keylen);
  44         kfree(buffer);
  45         return ret;
  46 }
  47
  48 static int hash_setkey(struct crypto_hash *crt, const u8 *key,
  49                 unsigned int keylen)
  50 {
  51         struct crypto_tfm *tfm = crypto_hash_tfm(crt);
  52         struct hash_alg *alg = &tfm->__crt_alg->cra_hash;
  53         unsigned long alignmask = crypto_hash_alignmask(crt);
  54
  55         if ((unsigned long)key & alignmask)
  56                 return hash_setkey_unaligned(crt, key, keylen);
  57
  58         return alg->setkey(crt, key, keylen);
  59 }
  60
  61 static int crypto_init_hash_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
  62 {
  63         struct hash_tfm *crt = &tfm->crt_hash;
  64         struct hash_alg *alg = &tfm->__crt_alg->cra_hash;
  65
  66         if (alg->digestsize > crypto_tfm_alg_blocksize(tfm))
  67                 return -EINVAL;
  68
  69         crt->init = alg->init;
  70         crt->update = alg->update;
  71         crt->final = alg->final;
  72         crt->digest = alg->digest;
  73         crt->setkey = hash_setkey;
  74         crt->digestsize = alg->digestsize;
  75
  76         return 0;
  77 }
  78
  79 static void crypto_hash_show(struct seq_file *m, struct crypto_alg *alg)
  80         __attribute__ ((unused));
  81 static void crypto_hash_show(struct seq_file *m, struct crypto_alg *alg)
  82 {
  83         seq_printf(m, "type         : hash\n");
  84         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
  85         seq_printf(m, "digestsize   : %u\n", alg->cra_hash.digestsize);
  86 }
  87
  88 const struct crypto_type crypto_hash_type = {
  89         .ctxsize = crypto_hash_ctxsize,
  90         .init = crypto_init_hash_ops,
  91 #ifdef CONFIG_PROC_FS
  92         .show = crypto_hash_show,
  93 #endif
  94 };
  95 EXPORT_SYMBOL_GPL(crypto_hash_type);
  96
  97 MODULE_LICENSE("GPL");
  98 MODULE_DESCRIPTION("Generic cryptographic hash type");