net/mac80211/aes_gcm.c

   1 /*
   2  * Copyright 2014-2015, Qualcomm Atheros, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/types.h>
  11 #include <linux/err.h>
  12 #include <crypto/aead.h>
  13
  14 #include <net/mac80211.h>
  15 #include "key.h"
  16 #include "aes_gcm.h"
  17
  18 void ieee80211_aes_gcm_encrypt(struct crypto_aead *tfm, u8 *j_0, u8 *aad,
  19                                u8 *data, size_t data_len, u8 *mic)
  20 {
  21         struct scatterlist sg[3];
  22
  23         char aead_req_data[sizeof(struct aead_request) +
  24                            crypto_aead_reqsize(tfm)]
  25                 __aligned(__alignof__(struct aead_request));
  26         struct aead_request *aead_req = (void *)aead_req_data;
  27
  28         memset(aead_req, 0, sizeof(aead_req_data));
  29
  30         sg_init_table(sg, 3);
  31         sg_set_buf(&sg[0], &aad[2], be16_to_cpup((__be16 *)aad));
  32         sg_set_buf(&sg[1], data, data_len);
  33         sg_set_buf(&sg[2], mic, IEEE80211_GCMP_MIC_LEN);
  34
  35         aead_request_set_tfm(aead_req, tfm);
  36         aead_request_set_crypt(aead_req, sg, sg, data_len, j_0);
  37         aead_request_set_ad(aead_req, sg[0].length);
  38
  39         crypto_aead_encrypt(aead_req);
  40 }
  41
  42 int ieee80211_aes_gcm_decrypt(struct crypto_aead *tfm, u8 *j_0, u8 *aad,
  43                               u8 *data, size_t data_len, u8 *mic)
  44 {
  45         struct scatterlist sg[3];
  46         char aead_req_data[sizeof(struct aead_request) +
  47                            crypto_aead_reqsize(tfm)]
  48                 __aligned(__alignof__(struct aead_request));
  49         struct aead_request *aead_req = (void *)aead_req_data;
  50
  51         if (data_len == 0)
  52                 return -EINVAL;
  53
  54         memset(aead_req, 0, sizeof(aead_req_data));
  55
  56         sg_init_table(sg, 3);
  57         sg_set_buf(&sg[0], &aad[2], be16_to_cpup((__be16 *)aad));
  58         sg_set_buf(&sg[1], data, data_len);
  59         sg_set_buf(&sg[2], mic, IEEE80211_GCMP_MIC_LEN);
  60
  61         aead_request_set_tfm(aead_req, tfm);
  62         aead_request_set_crypt(aead_req, sg, sg,
  63                                data_len + IEEE80211_GCMP_MIC_LEN, j_0);
  64         aead_request_set_ad(aead_req, sg[0].length);
  65
  66         return crypto_aead_decrypt(aead_req);
  67 }
  68
  69 struct crypto_aead *ieee80211_aes_gcm_key_setup_encrypt(const u8 key[],
  70                                                         size_t key_len)
  71 {
  72         struct crypto_aead *tfm;
  73         int err;
  74
  75         tfm = crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC);
  76         if (IS_ERR(tfm))
  77                 return tfm;
  78
  79         err = crypto_aead_setkey(tfm, key, key_len);
  80         if (err)
  81                 goto free_aead;
  82         err = crypto_aead_setauthsize(tfm, IEEE80211_GCMP_MIC_LEN);
  83         if (err)
  84                 goto free_aead;
  85
  86         return tfm;
  87
  88 free_aead:
  89         crypto_free_aead(tfm);
  90         return ERR_PTR(err);
  91 }
  92
  93 void ieee80211_aes_gcm_key_free(struct crypto_aead *tfm)
  94 {
  95         crypto_free_aead(tfm);
  96 }