net/mac80211/aes_ccm.c

   1 /*
   2  * Copyright 2003-2004, Instant802 Networks, Inc.
   3  * Copyright 2005-2006, Devicescape Software, Inc.
   4  *
   5  * Rewrite: Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/types.h>
  14 #include <linux/crypto.h>
  15 #include <linux/err.h>
  16 #include <crypto/aes.h>
  17
  18 #include <net/mac80211.h>
  19 #include "key.h"
  20 #include "aes_ccm.h"
  21
  22 void ieee80211_aes_ccm_encrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
  23                                u8 *data, size_t data_len, u8 *mic,
  24                                size_t mic_len)
  25 {
  26         struct scatterlist assoc, pt, ct[2];
  27
  28         char aead_req_data[sizeof(struct aead_request) +
  29                            crypto_aead_reqsize(tfm)]
  30                 __aligned(__alignof__(struct aead_request));
  31         struct aead_request *aead_req = (void *) aead_req_data;
  32
  33         memset(aead_req, 0, sizeof(aead_req_data));
  34
  35         sg_init_one(&pt, data, data_len);
  36         sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
  37         sg_init_table(ct, 2);
  38         sg_set_buf(&ct[0], data, data_len);
  39         sg_set_buf(&ct[1], mic, mic_len);
  40
  41         aead_request_set_tfm(aead_req, tfm);
  42         aead_request_set_assoc(aead_req, &assoc, assoc.length);
  43         aead_request_set_crypt(aead_req, &pt, ct, data_len, b_0);
  44
  45         crypto_aead_encrypt(aead_req);
  46 }
  47
  48 int ieee80211_aes_ccm_decrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
  49                               u8 *data, size_t data_len, u8 *mic,
  50                               size_t mic_len)
  51 {
  52         struct scatterlist assoc, pt, ct[2];
  53         char aead_req_data[sizeof(struct aead_request) +
  54                            crypto_aead_reqsize(tfm)]
  55                 __aligned(__alignof__(struct aead_request));
  56         struct aead_request *aead_req = (void *) aead_req_data;
  57
  58         if (data_len == 0)
  59                 return -EINVAL;
  60
  61         memset(aead_req, 0, sizeof(aead_req_data));
  62
  63         sg_init_one(&pt, data, data_len);
  64         sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
  65         sg_init_table(ct, 2);
  66         sg_set_buf(&ct[0], data, data_len);
  67         sg_set_buf(&ct[1], mic, mic_len);
  68
  69         aead_request_set_tfm(aead_req, tfm);
  70         aead_request_set_assoc(aead_req, &assoc, assoc.length);
  71         aead_request_set_crypt(aead_req, ct, &pt, data_len + mic_len, b_0);
  72
  73         return crypto_aead_decrypt(aead_req);
  74 }
  75
  76 struct crypto_aead *ieee80211_aes_key_setup_encrypt(const u8 key[],
  77                                                     size_t key_len,
  78                                                     size_t mic_len)
  79 {
  80         struct crypto_aead *tfm;
  81         int err;
  82
  83         tfm = crypto_alloc_aead("ccm(aes)", 0, CRYPTO_ALG_ASYNC);
  84         if (IS_ERR(tfm))
  85                 return tfm;
  86
  87         err = crypto_aead_setkey(tfm, key, key_len);
  88         if (err)
  89                 goto free_aead;
  90         err = crypto_aead_setauthsize(tfm, mic_len);
  91         if (err)
  92                 goto free_aead;
  93
  94         return tfm;
  95
  96 free_aead:
  97         crypto_free_aead(tfm);
  98         return ERR_PTR(err);
  99 }
 100
 101 void ieee80211_aes_key_free(struct crypto_aead *tfm)
 102 {
 103         crypto_free_aead(tfm);
 104 }