LXR linux/net/mac80211/aes

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * AES-GMAC for IEEE 802.11 BIP-GMAC-128 and BIP-GMAC-256
   4 * Copyright 2015, Qualcomm Atheros, Inc.
   5 */
   6
   7#include <linux/kernel.h>
   8#include <linux/types.h>
   9#include <linux/err.h>
  10#include <crypto/aead.h>
  11#include <crypto/aes.h>
  12
  13#include <net/mac80211.h>
  14#include "key.h"
  15#include "aes_gmac.h"
  16
  17int ieee80211_aes_gmac(struct crypto_aead *tfm, const u8 *aad, u8 *nonce,
  18                       const u8 *data, size_t data_len, u8 *mic)
  19{
  20        struct scatterlist sg[5];
  21        u8 *zero, *__aad, iv[AES_BLOCK_SIZE];
  22        struct aead_request *aead_req;
  23        int reqsize = sizeof(*aead_req) + crypto_aead_reqsize(tfm);
  24        const __le16 *fc;
  25        int ret;
  26
  27        if (data_len < GMAC_MIC_LEN)
  28                return -EINVAL;
  29
  30        aead_req = kzalloc(reqsize + GMAC_MIC_LEN + GMAC_AAD_LEN, GFP_ATOMIC);
  31        if (!aead_req)
  32                return -ENOMEM;
  33
  34        zero = (u8 *)aead_req + reqsize;
  35        __aad = zero + GMAC_MIC_LEN;
  36        memcpy(__aad, aad, GMAC_AAD_LEN);
  37
  38        fc = (const __le16 *)aad;
  39        if (ieee80211_is_beacon(*fc)) {
  40                /* mask Timestamp field to zero */
  41                sg_init_table(sg, 5);
  42                sg_set_buf(&sg[0], __aad, GMAC_AAD_LEN);
  43                sg_set_buf(&sg[1], zero, 8);
  44                sg_set_buf(&sg[2], data + 8, data_len - 8 - GMAC_MIC_LEN);
  45                sg_set_buf(&sg[3], zero, GMAC_MIC_LEN);
  46                sg_set_buf(&sg[4], mic, GMAC_MIC_LEN);
  47        } else {
  48                sg_init_table(sg, 4);
  49                sg_set_buf(&sg[0], __aad, GMAC_AAD_LEN);
  50                sg_set_buf(&sg[1], data, data_len - GMAC_MIC_LEN);
  51                sg_set_buf(&sg[2], zero, GMAC_MIC_LEN);
  52                sg_set_buf(&sg[3], mic, GMAC_MIC_LEN);
  53        }
  54
  55        memcpy(iv, nonce, GMAC_NONCE_LEN);
  56        memset(iv + GMAC_NONCE_LEN, 0, sizeof(iv) - GMAC_NONCE_LEN);
  57        iv[AES_BLOCK_SIZE - 1] = 0x01;
  58
  59        aead_request_set_tfm(aead_req, tfm);
  60        aead_request_set_crypt(aead_req, sg, sg, 0, iv);
  61        aead_request_set_ad(aead_req, GMAC_AAD_LEN + data_len);
  62
  63        ret = crypto_aead_encrypt(aead_req);
  64        kfree_sensitive(aead_req);
  65
  66        return ret;
  67}
  68
  69struct crypto_aead *ieee80211_aes_gmac_key_setup(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                err = crypto_aead_setauthsize(tfm, GMAC_MIC_LEN);
  82        if (!err)
  83                return tfm;
  84
  85        crypto_free_aead(tfm);
  86        return ERR_PTR(err);
  87}
  88
  89void ieee80211_aes_gmac_key_free(struct crypto_aead *tfm)
  90{
  91        crypto_free_aead(tfm);
  92}
  93