1d2912cb1SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 2765cb46aSJouni Malinen /* 3765cb46aSJouni Malinen * AES-128-CMAC with TLen 16 for IEEE 802.11w BIP 4765cb46aSJouni Malinen * Copyright 2008, Jouni Malinen <j@w1.fi> 5765cb46aSJouni Malinen */ 6765cb46aSJouni Malinen 7765cb46aSJouni Malinen #include <linux/kernel.h> 8765cb46aSJouni Malinen #include <linux/types.h> 9765cb46aSJouni Malinen #include <linux/crypto.h> 104afebd63SEmmanuel Grumbach #include <linux/export.h> 11765cb46aSJouni Malinen #include <linux/err.h> 120cd20a27SJohannes Berg #include <crypto/aes.h> 13765cb46aSJouni Malinen 14765cb46aSJouni Malinen #include <net/mac80211.h> 15765cb46aSJouni Malinen #include "key.h" 16765cb46aSJouni Malinen #include "aes_cmac.h" 17765cb46aSJouni Malinen 18765cb46aSJouni Malinen #define CMAC_TLEN 8 /* CMAC TLen = 64 bits (8 octets) */ 1956c52da2SJouni Malinen #define CMAC_TLEN_256 16 /* CMAC TLen = 128 bits (16 octets) */ 20765cb46aSJouni Malinen #define AAD_LEN 20 21765cb46aSJouni Malinen 2226717828SArd Biesheuvel static const u8 zero[CMAC_TLEN_256]; 23765cb46aSJouni Malinen 2426717828SArd Biesheuvel void ieee80211_aes_cmac(struct crypto_shash *tfm, const u8 *aad, 25765cb46aSJouni Malinen const u8 *data, size_t data_len, u8 *mic) 26765cb46aSJouni Malinen { 2726717828SArd Biesheuvel SHASH_DESC_ON_STACK(desc, tfm); 2826717828SArd Biesheuvel u8 out[AES_BLOCK_SIZE]; 292d5d4b0aSJouni Malinen const __le16 *fc; 30765cb46aSJouni Malinen 3126717828SArd Biesheuvel desc->tfm = tfm; 32765cb46aSJouni Malinen 3326717828SArd Biesheuvel crypto_shash_init(desc); 3426717828SArd Biesheuvel crypto_shash_update(desc, aad, AAD_LEN); 352d5d4b0aSJouni Malinen fc = (const __le16 *)aad; 362d5d4b0aSJouni Malinen if (ieee80211_is_beacon(*fc)) { 372d5d4b0aSJouni Malinen /* mask Timestamp field to zero */ 382d5d4b0aSJouni Malinen crypto_shash_update(desc, zero, 8); 392d5d4b0aSJouni Malinen crypto_shash_update(desc, data + 8, data_len - 8 - CMAC_TLEN); 402d5d4b0aSJouni Malinen } else { 4126717828SArd Biesheuvel crypto_shash_update(desc, data, data_len - CMAC_TLEN); 422d5d4b0aSJouni Malinen } 4326717828SArd Biesheuvel crypto_shash_finup(desc, zero, CMAC_TLEN, out); 4426717828SArd Biesheuvel 4526717828SArd Biesheuvel memcpy(mic, out, CMAC_TLEN); 46765cb46aSJouni Malinen } 47765cb46aSJouni Malinen 4826717828SArd Biesheuvel void ieee80211_aes_cmac_256(struct crypto_shash *tfm, const u8 *aad, 4956c52da2SJouni Malinen const u8 *data, size_t data_len, u8 *mic) 5056c52da2SJouni Malinen { 5126717828SArd Biesheuvel SHASH_DESC_ON_STACK(desc, tfm); 522d5d4b0aSJouni Malinen const __le16 *fc; 53765cb46aSJouni Malinen 5426717828SArd Biesheuvel desc->tfm = tfm; 5556c52da2SJouni Malinen 5626717828SArd Biesheuvel crypto_shash_init(desc); 5726717828SArd Biesheuvel crypto_shash_update(desc, aad, AAD_LEN); 582d5d4b0aSJouni Malinen fc = (const __le16 *)aad; 592d5d4b0aSJouni Malinen if (ieee80211_is_beacon(*fc)) { 602d5d4b0aSJouni Malinen /* mask Timestamp field to zero */ 612d5d4b0aSJouni Malinen crypto_shash_update(desc, zero, 8); 622d5d4b0aSJouni Malinen crypto_shash_update(desc, data + 8, 632d5d4b0aSJouni Malinen data_len - 8 - CMAC_TLEN_256); 642d5d4b0aSJouni Malinen } else { 6526717828SArd Biesheuvel crypto_shash_update(desc, data, data_len - CMAC_TLEN_256); 662d5d4b0aSJouni Malinen } 6726717828SArd Biesheuvel crypto_shash_finup(desc, zero, CMAC_TLEN_256, mic); 6856c52da2SJouni Malinen } 6956c52da2SJouni Malinen 7026717828SArd Biesheuvel struct crypto_shash *ieee80211_aes_cmac_key_setup(const u8 key[], 7156c52da2SJouni Malinen size_t key_len) 72765cb46aSJouni Malinen { 7326717828SArd Biesheuvel struct crypto_shash *tfm; 74765cb46aSJouni Malinen 7526717828SArd Biesheuvel tfm = crypto_alloc_shash("cmac(aes)", 0, 0); 761ac62ba7SBen Hutchings if (!IS_ERR(tfm)) 7726717828SArd Biesheuvel crypto_shash_setkey(tfm, key, key_len); 78765cb46aSJouni Malinen 79765cb46aSJouni Malinen return tfm; 80765cb46aSJouni Malinen } 81765cb46aSJouni Malinen 8226717828SArd Biesheuvel void ieee80211_aes_cmac_key_free(struct crypto_shash *tfm) 83765cb46aSJouni Malinen { 8426717828SArd Biesheuvel crypto_free_shash(tfm); 85765cb46aSJouni Malinen } 86