aes_cmac.rar_aes cmac_cmac

/* * AES-128-CMAC with TLen 16 for IEEE 802.11w BIP */ #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 AES_CMAC_KEY_LEN 16 #define CMAC_TLEN 8 /* CMAC TLen = 64 bits (8 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_128_cmac_vector(struct crypto_cipher *tfm, size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac) { 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, CMAC_TLEN); } 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_128_cmac_vector(tfm, 3, addr, len, mic); } struct crypto_cipher * ieee80211_aes_cmac_key_setup(const u8 key[]) { struct crypto_cipher *tfm; tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC); if (!IS_ERR(tfm)) crypto_cipher_setkey(tfm, key, AES_CMAC_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);