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 22 static const u8 zero[CMAC_TLEN_256]; 23 24 void 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 30 desc->tfm = tfm; 31 32 crypto_shash_init(desc); 33 crypto_shash_update(desc, aad, AAD_LEN); 34 crypto_shash_update(desc, data, data_len - CMAC_TLEN); 35 crypto_shash_finup(desc, zero, CMAC_TLEN, out); 36 37 memcpy(mic, out, CMAC_TLEN); 38 } 39 40 void ieee80211_aes_cmac_256(struct crypto_shash *tfm, const u8 *aad, 41 const u8 *data, size_t data_len, u8 *mic) 42 { 43 SHASH_DESC_ON_STACK(desc, tfm); 44 45 desc->tfm = tfm; 46 47 crypto_shash_init(desc); 48 crypto_shash_update(desc, aad, AAD_LEN); 49 crypto_shash_update(desc, data, data_len - CMAC_TLEN_256); 50 crypto_shash_finup(desc, zero, CMAC_TLEN_256, mic); 51 } 52 53 struct crypto_shash *ieee80211_aes_cmac_key_setup(const u8 key[], 54 size_t key_len) 55 { 56 struct crypto_shash *tfm; 57 58 tfm = crypto_alloc_shash("cmac(aes)", 0, 0); 59 if (!IS_ERR(tfm)) 60 crypto_shash_setkey(tfm, key, key_len); 61 62 return tfm; 63 } 64 65 void ieee80211_aes_cmac_key_free(struct crypto_shash *tfm) 66 { 67 crypto_free_shash(tfm); 68 } 69