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 int 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         struct aead_request *aead_req;
  27         int reqsize = sizeof(*aead_req) + crypto_aead_reqsize(tfm);
  28         u8 *__aad;
  29
  30         aead_req = kzalloc(reqsize + CCM_AAD_LEN, GFP_ATOMIC);
  31         if (!aead_req)
  32                 return -ENOMEM;
  33
  34         __aad = (u8 *)aead_req + reqsize;
  35         memcpy(__aad, aad, CCM_AAD_LEN);
  36
  37         sg_init_table(sg, 3);
  38         sg_set_buf(&sg[0], &__aad[2], be16_to_cpup((__be16 *)__aad));
  39         sg_set_buf(&sg[1], data, data_len);
  40         sg_set_buf(&sg[2], mic, mic_len);
  41
  42         aead_request_set_tfm(aead_req, tfm);
  43         aead_request_set_crypt(aead_req, sg, sg, data_len, b_0);
  44         aead_request_set_ad(aead_req, sg[0].length);
  45
  46         crypto_aead_encrypt(aead_req);
  47         kzfree(aead_req);
  48
  49         return 0;
  50 }
  51
  52 int ieee80211_aes_ccm_decrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
  53                               u8 *data, size_t data_len, u8 *mic,
  54                               size_t mic_len)
  55 {
  56         struct scatterlist sg[3];
  57         struct aead_request *aead_req;
  58         int reqsize = sizeof(*aead_req) + crypto_aead_reqsize(tfm);
  59         u8 *__aad;
  60         int err;
  61
  62         if (data_len == 0)
  63                 return -EINVAL;
  64
  65         aead_req = kzalloc(reqsize + CCM_AAD_LEN, GFP_ATOMIC);
  66         if (!aead_req)
  67                 return -ENOMEM;
  68
  69         __aad = (u8 *)aead_req + reqsize;
  70         memcpy(__aad, aad, CCM_AAD_LEN);
  71
  72         sg_init_table(sg, 3);
  73         sg_set_buf(&sg[0], &__aad[2], be16_to_cpup((__be16 *)__aad));
  74         sg_set_buf(&sg[1], data, data_len);
  75         sg_set_buf(&sg[2], mic, mic_len);
  76
  77         aead_request_set_tfm(aead_req, tfm);
  78         aead_request_set_crypt(aead_req, sg, sg, data_len + mic_len, b_0);
  79         aead_request_set_ad(aead_req, sg[0].length);
  80
  81         err = crypto_aead_decrypt(aead_req);
  82         kzfree(aead_req);
  83
  84         return err;
  85 }
  86
  87 struct crypto_aead *ieee80211_aes_key_setup_encrypt(const u8 key[],
  88                                                     size_t key_len,
  89                                                     size_t mic_len)
  90 {
  91         struct crypto_aead *tfm;
  92         int err;
  93
  94         tfm = crypto_alloc_aead("ccm(aes)", 0, CRYPTO_ALG_ASYNC);
  95         if (IS_ERR(tfm))
  96                 return tfm;
  97
  98         err = crypto_aead_setkey(tfm, key, key_len);
  99         if (err)
 100                 goto free_aead;
 101         err = crypto_aead_setauthsize(tfm, mic_len);
 102         if (err)
 103                 goto free_aead;
 104
 105         return tfm;
 106
 107 free_aead:
 108         crypto_free_aead(tfm);
 109         return ERR_PTR(err);
 110 }
 111
 112 void ieee80211_aes_key_free(struct crypto_aead *tfm)
 113 {
 114         crypto_free_aead(tfm);
 115 }