diff options
Diffstat (limited to 'kernel/net/mac80211/aes_cmac.c')
| -rw-r--r-- | kernel/net/mac80211/aes_cmac.c | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/kernel/net/mac80211/aes_cmac.c b/kernel/net/mac80211/aes_cmac.c new file mode 100644 index 000000000..4192806be --- /dev/null +++ b/kernel/net/mac80211/aes_cmac.c @@ -0,0 +1,164 @@ +/* + * AES-128-CMAC with TLen 16 for IEEE 802.11w BIP + * Copyright 2008, Jouni Malinen <j@w1.fi> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/crypto.h> +#include <linux/export.h> +#include <linux/err.h> +#include <crypto/aes.h> + +#include <net/mac80211.h> +#include "key.h" +#include "aes_cmac.h" + +#define CMAC_TLEN 8 /* CMAC TLen = 64 bits (8 octets) */ +#define CMAC_TLEN_256 16 /* CMAC TLen = 128 bits (16 octets) */ +#define AAD_LEN 20 + + +static void gf_mulx(u8 *pad) +{ + int i, carry; + + carry = pad[0] & 0x80; + for (i = 0; i < AES_BLOCK_SIZE - 1; i++) + pad[i] = (pad[i] << 1) | (pad[i + 1] >> 7); + pad[AES_BLOCK_SIZE - 1] <<= 1; + if (carry) + pad[AES_BLOCK_SIZE - 1] ^= 0x87; +} + +static void aes_cmac_vector(struct crypto_cipher *tfm, size_t num_elem, + const u8 *addr[], const size_t *len, u8 *mac, + size_t mac_len) +{ + u8 cbc[AES_BLOCK_SIZE], pad[AES_BLOCK_SIZE]; + const u8 *pos, *end; + size_t i, e, left, total_len; + + memset(cbc, 0, AES_BLOCK_SIZE); + + total_len = 0; + for (e = 0; e < num_elem; e++) + total_len += len[e]; + left = total_len; + + e = 0; + pos = addr[0]; + end = pos + len[0]; + + while (left >= AES_BLOCK_SIZE) { + for (i = 0; i < AES_BLOCK_SIZE; i++) { + cbc[i] ^= *pos++; + if (pos >= end) { + e++; + pos = addr[e]; + end = pos + len[e]; + } + } + if (left > AES_BLOCK_SIZE) + crypto_cipher_encrypt_one(tfm, cbc, cbc); + left -= AES_BLOCK_SIZE; + } + + memset(pad, 0, AES_BLOCK_SIZE); + crypto_cipher_encrypt_one(tfm, pad, pad); + gf_mulx(pad); + + if (left || total_len == 0) { + for (i = 0; i < left; i++) { + cbc[i] ^= *pos++; + if (pos >= end) { + e++; + pos = addr[e]; + end = pos + len[e]; + } + } + cbc[left] ^= 0x80; + gf_mulx(pad); + } + + for (i = 0; i < AES_BLOCK_SIZE; i++) + pad[i] ^= cbc[i]; + crypto_cipher_encrypt_one(tfm, pad, pad); + memcpy(mac, pad, mac_len); +} + + +void ieee80211_aes_cmac(struct crypto_cipher *tfm, const u8 *aad, + const u8 *data, size_t data_len, u8 *mic) +{ + const u8 *addr[3]; + size_t len[3]; + u8 zero[CMAC_TLEN]; + + memset(zero, 0, CMAC_TLEN); + addr[0] = aad; + len[0] = AAD_LEN; + addr[1] = data; + len[1] = data_len - CMAC_TLEN; + addr[2] = zero; + len[2] = CMAC_TLEN; + + aes_cmac_vector(tfm, 3, addr, len, mic, CMAC_TLEN); +} + +void ieee80211_aes_cmac_256(struct crypto_cipher *tfm, const u8 *aad, + const u8 *data, size_t data_len, u8 *mic) +{ + const u8 *addr[3]; + size_t len[3]; + u8 zero[CMAC_TLEN_256]; + + memset(zero, 0, CMAC_TLEN_256); + addr[0] = aad; + len[0] = AAD_LEN; + addr[1] = data; + len[1] = data_len - CMAC_TLEN_256; + addr[2] = zero; + len[2] = CMAC_TLEN_256; + + aes_cmac_vector(tfm, 3, addr, len, mic, CMAC_TLEN_256); +} + +struct crypto_cipher *ieee80211_aes_cmac_key_setup(const u8 key[], + size_t key_len) +{ + struct crypto_cipher *tfm; + + tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC); + if (!IS_ERR(tfm)) + crypto_cipher_setkey(tfm, key, key_len); + + return tfm; +} + + +void ieee80211_aes_cmac_key_free(struct crypto_cipher *tfm) +{ + crypto_free_cipher(tfm); +} + +void ieee80211_aes_cmac_calculate_k1_k2(struct ieee80211_key_conf *keyconf, + u8 *k1, u8 *k2) +{ + u8 l[AES_BLOCK_SIZE] = {}; + struct ieee80211_key *key = + container_of(keyconf, struct ieee80211_key, conf); + + crypto_cipher_encrypt_one(key->u.aes_cmac.tfm, l, l); + + memcpy(k1, l, AES_BLOCK_SIZE); + gf_mulx(k1); + + memcpy(k2, k1, AES_BLOCK_SIZE); + gf_mulx(k2); +} +EXPORT_SYMBOL(ieee80211_aes_cmac_calculate_k1_k2); |