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/err.h>
  15 #include <crypto/aead.h>
  16
  17 #include <net/mac80211.h>
  18 #include "key.h"
  19 #include "aes_ccm.h"
  20
  21 void ieee80211_aes_ccm_encrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
  22                                u8 *data, size_t data_len, u8 *mic,
  23                                size_t mic_len)
  24 {
  25         struct scatterlist sg[3];
  26
  27         char aead_req_data[sizeof(struct aead_request) +
  28                            crypto_aead_reqsize(tfm)]
  29                 __aligned(__alignof__(struct aead_request));
  30         struct aead_request *aead_req = (void *) aead_req_data;
  31
  32         memset(aead_req, 0, sizeof(aead_req_data));
  33
  34         sg_init_table(sg, 3);
  35         sg_set_buf(&sg[0], &aad[2], be16_to_cpup((__be16 *)aad));
  36         sg_set_buf(&sg[1], data, data_len);
  37         sg_set_buf(&sg[2], mic, mic_len);
  38
  39         aead_request_set_tfm(aead_req, tfm);
  40         aead_request_set_crypt(aead_req, sg, sg, data_len, b_0);
  41         aead_request_set_ad(aead_req, sg[0].length);
  42
  43         crypto_aead_encrypt(aead_req);
  44 }
  45
  46 int ieee80211_aes_ccm_decrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
  47                               u8 *data, size_t data_len, u8 *mic,
  48                               size_t mic_len)
  49 {
  50         struct scatterlist sg[3];
  51         char aead_req_data[sizeof(struct aead_request) +
  52                            crypto_aead_reqsize(tfm)]
  53                 __aligned(__alignof__(struct aead_request));
  54         struct aead_request *aead_req = (void *) aead_req_data;
  55
  56         if (data_len == 0)
  57                 return -EINVAL;
  58
  59         memset(aead_req, 0, sizeof(aead_req_data));
  60
  61         sg_init_table(sg, 3);
  62         sg_set_buf(&sg[0], &aad[2], be16_to_cpup((__be16 *)aad));
  63         sg_set_buf(&sg[1], data, data_len);
  64         sg_set_buf(&sg[2], mic, mic_len);
  65
  66         aead_request_set_tfm(aead_req, tfm);
  67         aead_request_set_crypt(aead_req, sg, sg, data_len + mic_len, b_0);
  68         aead_request_set_ad(aead_req, sg[0].length);
  69
  70         return crypto_aead_decrypt(aead_req);
  71 }
  72
  73 struct crypto_aead *ieee80211_aes_key_setup_encrypt(const u8 key[],
  74                                                     size_t key_len,
  75                                                     size_t mic_len)
  76 {
  77         struct crypto_aead *tfm;
  78         int err;
  79
  80         tfm = crypto_alloc_aead("ccm(aes)", 0, CRYPTO_ALG_ASYNC);
  81         if (IS_ERR(tfm))
  82                 return tfm;
  83
  84         err = crypto_aead_setkey(tfm, key, key_len);
  85         if (err)
  86                 goto free_aead;
  87         err = crypto_aead_setauthsize(tfm, mic_len);
  88         if (err)
  89                 goto free_aead;
  90
  91         return tfm;
  92
  93 free_aead:
  94         crypto_free_aead(tfm);
  95         return ERR_PTR(err);
  96 }
  97
  98 void ieee80211_aes_key_free(struct crypto_aead *tfm)
  99 {
 100         crypto_free_aead(tfm);
 101 }