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
  20#define GMAC_MIC_LEN 16
  21#define GMAC_NONCE_LEN 12
  22#define AAD_LEN 20
  23
  24int ieee80211_aes_gmac(struct crypto_aead *tfm, const u8 *aad, u8 *nonce,
  25                       const u8 *data, size_t data_len, u8 *mic)
  26{
  27        struct scatterlist sg[4];
  28        char aead_req_data[sizeof(struct aead_request) +
  29                           crypto_aead_reqsize(tfm)]
  30                __aligned(__alignof__(struct aead_request));
  31        struct aead_request *aead_req = (void *)aead_req_data;
  32        u8 zero[GMAC_MIC_LEN], iv[AES_BLOCK_SIZE];
  33
  34        if (data_len < GMAC_MIC_LEN)
  35                return -EINVAL;
  36
  37        memset(aead_req, 0, sizeof(aead_req_data));
  38
  39        memset(zero, 0, GMAC_MIC_LEN);
  40        sg_init_table(sg, 4);
  41        sg_set_buf(&sg[0], aad, AAD_LEN);
  42        sg_set_buf(&sg[1], data, data_len - GMAC_MIC_LEN);
  43        sg_set_buf(&sg[2], zero, GMAC_MIC_LEN);
  44        sg_set_buf(&sg[3], mic, GMAC_MIC_LEN);
  45
  46        memcpy(iv, nonce, GMAC_NONCE_LEN);
  47        memset(iv + GMAC_NONCE_LEN, 0, sizeof(iv) - GMAC_NONCE_LEN);
  48        iv[AES_BLOCK_SIZE - 1] = 0x01;
  49
  50        aead_request_set_tfm(aead_req, tfm);
  51        aead_request_set_crypt(aead_req, sg, sg, 0, iv);
  52        aead_request_set_ad(aead_req, AAD_LEN + data_len);
  53
  54        crypto_aead_encrypt(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