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/slab.h>
  16 #include <linux/seq_file.h>
  17
  18 #include "internal.h"
  19
  20 static unsigned int crypto_hash_ctxsize(struct crypto_alg *alg, u32 type,
  21                                         u32 mask)
  22 {
  23         return alg->cra_ctxsize;
  24 }
  25
  26 static int hash_setkey_unaligned(struct crypto_hash *crt, const u8 *key,
  27                                  unsigned int keylen)
  28 {
  29         struct crypto_tfm *tfm = crypto_hash_tfm(crt);
  30         struct hash_alg *alg = &tfm->__crt_alg->cra_hash;
  31         unsigned long alignmask = crypto_hash_alignmask(crt);
  32         int ret;
  33         u8 *buffer, *alignbuffer;
  34         unsigned long absize;
  35
  36         absize = keylen + alignmask;
  37         buffer = kmalloc(absize, GFP_ATOMIC);
  38         if (!buffer)
  39                 return -ENOMEM;
  40
  41         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  42         memcpy(alignbuffer, key, keylen);
  43         ret = alg->setkey(crt, alignbuffer, keylen);
  44         memset(alignbuffer, 0, keylen);
  45         kfree(buffer);
  46         return ret;
  47 }
  48
  49 static int hash_setkey(struct crypto_hash *crt, const u8 *key,
  50                        unsigned int keylen)
  51 {
  52         struct crypto_tfm *tfm = crypto_hash_tfm(crt);
  53         struct hash_alg *alg = &tfm->__crt_alg->cra_hash;
  54         unsigned long alignmask = crypto_hash_alignmask(crt);
  55
  56         if ((unsigned long)key & alignmask)
  57                 return hash_setkey_unaligned(crt, key, keylen);
  58
  59         return alg->setkey(crt, key, keylen);
  60 }
  61
  62 static int crypto_init_hash_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
  63 {
  64         struct hash_tfm *crt = &tfm->crt_hash;
  65         struct hash_alg *alg = &tfm->__crt_alg->cra_hash;
  66
  67         if (alg->digestsize > crypto_tfm_alg_blocksize(tfm))
  68                 return -EINVAL;
  69
  70         crt->init = alg->init;
  71         crt->update = alg->update;
  72         crt->final = alg->final;
  73         crt->digest = alg->digest;
  74         crt->setkey = hash_setkey;
  75         crt->digestsize = alg->digestsize;
  76
  77         return 0;
  78 }
  79
  80 static void crypto_hash_show(struct seq_file *m, struct crypto_alg *alg)
  81         __attribute__ ((unused));
  82 static void crypto_hash_show(struct seq_file *m, struct crypto_alg *alg)
  83 {
  84         seq_printf(m, "type         : hash\n");
  85         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
  86         seq_printf(m, "digestsize   : %u\n", alg->cra_hash.digestsize);
  87 }
  88
  89 const struct crypto_type crypto_hash_type = {
  90         .ctxsize = crypto_hash_ctxsize,
  91         .init = crypto_init_hash_ops,
  92 #ifdef CONFIG_PROC_FS
  93         .show = crypto_hash_show,
  94 #endif
  95 };
  96 EXPORT_SYMBOL_GPL(crypto_hash_type);
  97
  98 MODULE_LICENSE("GPL");
  99 MODULE_DESCRIPTION("Generic cryptographic hash type");