LXR linux/net/mac80211/aes

   1/*
   2 * AES-GMAC for IEEE 802.11 BIP-GMAC-128 and BIP-GMAC-256
   3 * Copyright 2015, Qualcomm Atheros, Inc.
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License version 2 as
   7 * published by the Free Software Foundation.
   8 */
   9
  10#include <linux/kernel.h>
  11#include <linux/types.h>
  12#include <linux/err.h>
  13#include <crypto/aead.h>
  14#include <crypto/aes.h>
  15
  16#include <net/mac80211.h>
  17#include "key.h"
  18#include "aes_gmac.h"
  19
  20int ieee80211_aes_gmac(struct crypto_aead *tfm, const u8 *aad, u8 *nonce,
  21                       const u8 *data, size_t data_len, u8 *mic)
  22{
  23        struct scatterlist sg[4];
  24        u8 *zero, *__aad, iv[AES_BLOCK_SIZE];
  25        struct aead_request *aead_req;
  26        int reqsize = sizeof(*aead_req) + crypto_aead_reqsize(tfm);
  27
  28        if (data_len < GMAC_MIC_LEN)
  29                return -EINVAL;
  30
  31        aead_req = kzalloc(reqsize + GMAC_MIC_LEN + GMAC_AAD_LEN, GFP_ATOMIC);
  32        if (!aead_req)
  33                return -ENOMEM;
  34
  35        zero = (u8 *)aead_req + reqsize;
  36        __aad = zero + GMAC_MIC_LEN;
  37        memcpy(__aad, aad, GMAC_AAD_LEN);
  38
  39        sg_init_table(sg, 4);
  40        sg_set_buf(&sg[0], __aad, GMAC_AAD_LEN);
  41        sg_set_buf(&sg[1], data, data_len - GMAC_MIC_LEN);
  42        sg_set_buf(&sg[2], zero, GMAC_MIC_LEN);
  43        sg_set_buf(&sg[3], mic, GMAC_MIC_LEN);
  44
  45        memcpy(iv, nonce, GMAC_NONCE_LEN);
  46        memset(iv + GMAC_NONCE_LEN, 0, sizeof(iv) - GMAC_NONCE_LEN);
  47        iv[AES_BLOCK_SIZE - 1] = 0x01;
  48
  49        aead_request_set_tfm(aead_req, tfm);
  50        aead_request_set_crypt(aead_req, sg, sg, 0, iv);
  51        aead_request_set_ad(aead_req, GMAC_AAD_LEN + data_len);
  52
  53        crypto_aead_encrypt(aead_req);
  54        kzfree(aead_req);
  55
  56        return 0;
  57}
  58
  59struct crypto_aead *ieee80211_aes_gmac_key_setup(const u8 key[],
  60                                                 size_t key_len)
  61{
  62        struct crypto_aead *tfm;
  63        int err;
  64
  65        tfm = crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC);
  66        if (IS_ERR(tfm))
  67                return tfm;
  68
  69        err = crypto_aead_setkey(tfm, key, key_len);
  70        if (!err)
  71                err = crypto_aead_setauthsize(tfm, GMAC_MIC_LEN);
  72        if (!err)
  73                return tfm;
  74
  75        crypto_free_aead(tfm);
  76        return ERR_PTR(err);
  77}
  78
  79void ieee80211_aes_gmac_key_free(struct crypto_aead *tfm)
  80{
  81        crypto_free_aead(tfm);
  82}
  83