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 {
  25         struct scatterlist assoc, pt, ct[2];
  26         struct {
  27                 struct aead_request     req;
  28                 u8                      priv[crypto_aead_reqsize(tfm)];
  29         } aead_req;
  30
  31         memset(&aead_req, 0, sizeof(aead_req));
  32
  33         sg_init_one(&pt, data, data_len);
  34         sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
  35         sg_init_table(ct, 2);
  36         sg_set_buf(&ct[0], data, data_len);
  37         sg_set_buf(&ct[1], mic, IEEE80211_CCMP_MIC_LEN);
  38
  39         aead_request_set_tfm(&aead_req.req, tfm);
  40         aead_request_set_assoc(&aead_req.req, &assoc, assoc.length);
  41         aead_request_set_crypt(&aead_req.req, &pt, ct, data_len, b_0);
  42
  43         crypto_aead_encrypt(&aead_req.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 {
  49         struct scatterlist assoc, pt, ct[2];
  50         struct {
  51                 struct aead_request     req;
  52                 u8                      priv[crypto_aead_reqsize(tfm)];
  53         } aead_req;
  54
  55         memset(&aead_req, 0, sizeof(aead_req));
  56
  57         sg_init_one(&pt, data, data_len);
  58         sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
  59         sg_init_table(ct, 2);
  60         sg_set_buf(&ct[0], data, data_len);
  61         sg_set_buf(&ct[1], mic, IEEE80211_CCMP_MIC_LEN);
  62
  63         aead_request_set_tfm(&aead_req.req, tfm);
  64         aead_request_set_assoc(&aead_req.req, &assoc, assoc.length);
  65         aead_request_set_crypt(&aead_req.req, ct, &pt,
  66                                data_len + IEEE80211_CCMP_MIC_LEN, b_0);
  67
  68         return crypto_aead_decrypt(&aead_req.req);
  69 }
  70
  71 struct crypto_aead *ieee80211_aes_key_setup_encrypt(const u8 key[])
  72 {
  73         struct crypto_aead *tfm;
  74         int err;
  75
  76         tfm = crypto_alloc_aead("ccm(aes)", 0, CRYPTO_ALG_ASYNC);
  77         if (IS_ERR(tfm))
  78                 return tfm;
  79
  80         err = crypto_aead_setkey(tfm, key, WLAN_KEY_LEN_CCMP);
  81         if (!err)
  82                 err = crypto_aead_setauthsize(tfm, IEEE80211_CCMP_MIC_LEN);
  83         if (!err)
  84                 return tfm;
  85
  86         crypto_free_aead(tfm);
  87         return ERR_PTR(err);
  88 }
  89
  90 void ieee80211_aes_key_free(struct crypto_aead *tfm)
  91 {
  92         crypto_free_aead(tfm);
  93 }