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 int crypto_aead_setauthsize(struct crypto_aead *tfm, unsigned int authsize)
  57 {
  58         int err;
  59
  60         if (authsize > crypto_aead_alg(tfm)->maxauthsize)
  61                 return -EINVAL;
  62
  63         if (crypto_aead_alg(tfm)->setauthsize) {
  64                 err = crypto_aead_alg(tfm)->setauthsize(tfm, authsize);
  65                 if (err)
  66                         return err;
  67         }
  68
  69         crypto_aead_crt(tfm)->authsize = authsize;
  70         return 0;
  71 }
  72 EXPORT_SYMBOL_GPL(crypto_aead_setauthsize);
  73
  74 static unsigned int crypto_aead_ctxsize(struct crypto_alg *alg, u32 type,
  75                                         u32 mask)
  76 {
  77         return alg->cra_ctxsize;
  78 }
  79
  80 static int crypto_init_aead_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
  81 {
  82         struct aead_alg *alg = &tfm->__crt_alg->cra_aead;
  83         struct aead_tfm *crt = &tfm->crt_aead;
  84
  85         if (max(alg->maxauthsize, alg->ivsize) > PAGE_SIZE / 8)
  86                 return -EINVAL;
  87
  88         crt->setkey = setkey;
  89         crt->encrypt = alg->encrypt;
  90         crt->decrypt = alg->decrypt;
  91         crt->ivsize = alg->ivsize;
  92         crt->authsize = alg->maxauthsize;
  93
  94         return 0;
  95 }
  96
  97 static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
  98         __attribute__ ((unused));
  99 static void crypto_aead_show(struct seq_file *m, struct crypto_alg *alg)
 100 {
 101         struct aead_alg *aead = &alg->cra_aead;
 102
 103         seq_printf(m, "type         : aead\n");
 104         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
 105         seq_printf(m, "ivsize       : %u\n", aead->ivsize);
 106         seq_printf(m, "maxauthsize  : %u\n", aead->maxauthsize);
 107 }
 108
 109 const struct crypto_type crypto_aead_type = {
 110         .ctxsize = crypto_aead_ctxsize,
 111         .init = crypto_init_aead_ops,
 112 #ifdef CONFIG_PROC_FS
 113         .show = crypto_aead_show,
 114 #endif
 115 };
 116 EXPORT_SYMBOL_GPL(crypto_aead_type);
 117
 118 MODULE_LICENSE("GPL");
 119 MODULE_DESCRIPTION("Authenticated Encryption with Associated Data (AEAD)");