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/crypto.h>
  12 #include <linux/err.h>
  13 #include <crypto/aes.h>
  14
  15 #include <net/mac80211.h>
  16 #include "key.h"
  17 #include "aes_gcm.h"
  18
  19 void ieee80211_aes_gcm_encrypt(struct crypto_aead *tfm, u8 *j_0, u8 *aad,
  20                                u8 *data, size_t data_len, u8 *mic)
  21 {
  22         struct scatterlist assoc, pt, ct[2];
  23
  24         char aead_req_data[sizeof(struct aead_request) +
  25                            crypto_aead_reqsize(tfm)]
  26                 __aligned(__alignof__(struct aead_request));
  27         struct aead_request *aead_req = (void *)aead_req_data;
  28
  29         memset(aead_req, 0, sizeof(aead_req_data));
  30
  31         sg_init_one(&pt, data, data_len);
  32         sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
  33         sg_init_table(ct, 2);
  34         sg_set_buf(&ct[0], data, data_len);
  35         sg_set_buf(&ct[1], mic, IEEE80211_GCMP_MIC_LEN);
  36
  37         aead_request_set_tfm(aead_req, tfm);
  38         aead_request_set_assoc(aead_req, &assoc, assoc.length);
  39         aead_request_set_crypt(aead_req, &pt, ct, data_len, j_0);
  40
  41         crypto_aead_encrypt(aead_req);
  42 }
  43
  44 int ieee80211_aes_gcm_decrypt(struct crypto_aead *tfm, u8 *j_0, u8 *aad,
  45                               u8 *data, size_t data_len, u8 *mic)
  46 {
  47         struct scatterlist assoc, pt, ct[2];
  48         char aead_req_data[sizeof(struct aead_request) +
  49                            crypto_aead_reqsize(tfm)]
  50                 __aligned(__alignof__(struct aead_request));
  51         struct aead_request *aead_req = (void *)aead_req_data;
  52
  53         if (data_len == 0)
  54                 return -EINVAL;
  55
  56         memset(aead_req, 0, sizeof(aead_req_data));
  57
  58         sg_init_one(&pt, data, data_len);
  59         sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
  60         sg_init_table(ct, 2);
  61         sg_set_buf(&ct[0], data, data_len);
  62         sg_set_buf(&ct[1], mic, IEEE80211_GCMP_MIC_LEN);
  63
  64         aead_request_set_tfm(aead_req, tfm);
  65         aead_request_set_assoc(aead_req, &assoc, assoc.length);
  66         aead_request_set_crypt(aead_req, ct, &pt,
  67                                data_len + IEEE80211_GCMP_MIC_LEN, j_0);
  68
  69         return crypto_aead_decrypt(aead_req);
  70 }
  71
  72 struct crypto_aead *ieee80211_aes_gcm_key_setup_encrypt(const u8 key[],
  73                                                         size_t key_len)
  74 {
  75         struct crypto_aead *tfm;
  76         int err;
  77
  78         tfm = crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC);
  79         if (IS_ERR(tfm))
  80                 return tfm;
  81
  82         err = crypto_aead_setkey(tfm, key, key_len);
  83         if (err)
  84                 goto free_aead;
  85         err = crypto_aead_setauthsize(tfm, IEEE80211_GCMP_MIC_LEN);
  86         if (err)
  87                 goto free_aead;
  88
  89         return tfm;
  90
  91 free_aead:
  92         crypto_free_aead(tfm);
  93         return ERR_PTR(err);
  94 }
  95
  96 void ieee80211_aes_gcm_key_free(struct crypto_aead *tfm)
  97 {
  98         crypto_free_aead(tfm);
  99 }