crypto/aead.c

   1 /*
   2  * AEAD: Authenticated Encryption with Associated Data
   3  *
   4  * This file provides API support for AEAD algorithms.
   5  *
   6  * Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.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
  15 #include <crypto/algapi.h>
  16 #include <linux/errno.h>
  17 #include <linux/init.h>
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/slab.h>
  21 #include <linux/seq_file.h>
  22
  23 static int setkey_unaligned(struct crypto_aead *tfm, const u8 *key,
  24                             unsigned int keylen)
  25 {
  26         struct aead_alg *aead = crypto_aead_alg(tfm);
  27         unsigned long alignmask = crypto_aead_alignmask(tfm);
  28         int ret;
  29         u8 *buffer, *alignbuffer;
  30         unsigned long absize;
  31
  32         absize = keylen + alignmask;
  33         buffer = kmalloc(absize, GFP_ATOMIC);
  34         if (!buffer)
  35                 return -ENOMEM;
  36
  37         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
  38         memcpy(alignbuffer, key, keylen);
  39         ret = aead->setkey(tfm, alignbuffer, keylen);
  40         memset(alignbuffer, 0, keylen);
  41         kfree(buffer);
  42         return ret;
  43 }
  44
  45 static int setkey(struct crypto_aead *tfm, const u8 *key, unsigned int keylen)
  46 {
  47         struct aead_alg *aead = crypto_aead_alg(tfm);
  48         unsigned long alignmask = crypto_aead_alignmask(tfm);
  49
  50         if ((unsigned long)key & alignmask)
  51                 return setkey_unaligned(tfm, key, keylen);
  52
  53         return aead->setkey(tfm, key, keylen);
  54 }
  55
  56 static unsigned int crypto_aead_ctxsize(struct crypto_alg *alg, u32 type,
  57                                         u32 mask)
  58 {
  59         return alg->cra_ctxsize;
  60 }
  61
  62 static int crypto_init_aead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
  63 {
  64         struct aead_alg *alg = &tfm->__crt_alg->cra_aead;
  65         struct aead_tfm *crt = &tfm->crt_aead;
  66
  67         if (max(alg->authsize, alg->ivsize) > PAGE_SIZE / 8)
  68                 return -EINVAL;
  69
  70         crt->setkey = setkey;
  71         crt->encrypt = alg->encrypt;
  72         crt->decrypt = alg->decrypt;
  73         crt->ivsize = alg->ivsize;
  74         crt->authsize = alg->authsize;
  75
  76         return 0;
  77 }
  78
  79 static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
  80         __attribute__ ((unused));
  81 static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
  82 {
  83         struct aead_alg *aead = &alg->cra_aead;
  84
  85         seq_printf(m, "type         : aead\n");
  86         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
  87         seq_printf(m, "ivsize       : %u\n", aead->ivsize);
  88         seq_printf(m, "authsize     : %u\n", aead->authsize);
  89 }
  90
  91 const struct crypto_type crypto_aead_type = {
  92         .ctxsize = crypto_aead_ctxsize,
  93         .init = crypto_init_aead_ops,
  94 #ifdef CONFIG_PROC_FS
  95         .show = crypto_aead_show,
  96 #endif
  97 };
  98 EXPORT_SYMBOL_GPL(crypto_aead_type);
  99
 100 MODULE_LICENSE("GPL");
 101 MODULE_DESCRIPTION("Authenticated Encryption with Associated Data (AEAD)");