LXR linux/net/mac80211/aes

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * AES-128-CMAC with TLen 16 for IEEE 802.11w BIP
   4 * Copyright 2008, Jouni Malinen <j@w1.fi>
   5 */
   6
   7#include <linux/kernel.h>
   8#include <linux/types.h>
   9#include <linux/crypto.h>
  10#include <linux/export.h>
  11#include <linux/err.h>
  12#include <crypto/aes.h>
  13
  14#include <net/mac80211.h>
  15#include "key.h"
  16#include "aes_cmac.h"
  17
  18#define CMAC_TLEN 8 /* CMAC TLen = 64 bits (8 octets) */
  19#define CMAC_TLEN_256 16 /* CMAC TLen = 128 bits (16 octets) */
  20#define AAD_LEN 20
  21
  22static const u8 zero[CMAC_TLEN_256];
  23
  24void ieee80211_aes_cmac(struct crypto_shash *tfm, const u8 *aad,
  25                        const u8 *data, size_t data_len, u8 *mic)
  26{
  27        SHASH_DESC_ON_STACK(desc, tfm);
  28        u8 out[AES_BLOCK_SIZE];
  29        const __le16 *fc;
  30
  31        desc->tfm = tfm;
  32
  33        crypto_shash_init(desc);
  34        crypto_shash_update(desc, aad, AAD_LEN);
  35        fc = (const __le16 *)aad;
  36        if (ieee80211_is_beacon(*fc)) {
  37                /* mask Timestamp field to zero */
  38                crypto_shash_update(desc, zero, 8);
  39                crypto_shash_update(desc, data + 8, data_len - 8 - CMAC_TLEN);
  40        } else {
  41                crypto_shash_update(desc, data, data_len - CMAC_TLEN);
  42        }
  43        crypto_shash_finup(desc, zero, CMAC_TLEN, out);
  44
  45        memcpy(mic, out, CMAC_TLEN);
  46}
  47
  48void ieee80211_aes_cmac_256(struct crypto_shash *tfm, const u8 *aad,
  49                            const u8 *data, size_t data_len, u8 *mic)
  50{
  51        SHASH_DESC_ON_STACK(desc, tfm);
  52        const __le16 *fc;
  53
  54        desc->tfm = tfm;
  55
  56        crypto_shash_init(desc);
  57        crypto_shash_update(desc, aad, AAD_LEN);
  58        fc = (const __le16 *)aad;
  59        if (ieee80211_is_beacon(*fc)) {
  60                /* mask Timestamp field to zero */
  61                crypto_shash_update(desc, zero, 8);
  62                crypto_shash_update(desc, data + 8,
  63                                    data_len - 8 - CMAC_TLEN_256);
  64        } else {
  65                crypto_shash_update(desc, data, data_len - CMAC_TLEN_256);
  66        }
  67        crypto_shash_finup(desc, zero, CMAC_TLEN_256, mic);
  68}
  69
  70struct crypto_shash *ieee80211_aes_cmac_key_setup(const u8 key[],
  71                                                  size_t key_len)
  72{
  73        struct crypto_shash *tfm;
  74
  75        tfm = crypto_alloc_shash("cmac(aes)", 0, 0);
  76        if (!IS_ERR(tfm))
  77                crypto_shash_setkey(tfm, key, key_len);
  78
  79        return tfm;
  80}
  81
  82void ieee80211_aes_cmac_key_free(struct crypto_shash *tfm)
  83{
  84        crypto_free_shash(tfm);
  85}
  86