| Jouni Malinen | 8ade538 | 2015-01-24 19:52:09 +0200 | [diff] [blame^] | 1 | /* |
| 2 | * AES-GMAC for IEEE 802.11 BIP-GMAC-128 and BIP-GMAC-256 |
| 3 | * Copyright 2015, Qualcomm Atheros, Inc. |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License version 2 as |
| 7 | * published by the Free Software Foundation. |
| 8 | */ |
| 9 | |
| 10 | #include <linux/kernel.h> |
| 11 | #include <linux/types.h> |
| 12 | #include <linux/crypto.h> |
| 13 | #include <linux/err.h> |
| 14 | #include <crypto/aes.h> |
| 15 | |
| 16 | #include <net/mac80211.h> |
| 17 | #include "key.h" |
| 18 | #include "aes_gmac.h" |
| 19 | |
| 20 | #define GMAC_MIC_LEN 16 |
| 21 | #define GMAC_NONCE_LEN 12 |
| 22 | #define AAD_LEN 20 |
| 23 | |
| 24 | int ieee80211_aes_gmac(struct crypto_aead *tfm, const u8 *aad, u8 *nonce, |
| 25 | const u8 *data, size_t data_len, u8 *mic) |
| 26 | { |
| 27 | struct scatterlist sg[3], ct[1]; |
| 28 | char aead_req_data[sizeof(struct aead_request) + |
| 29 | crypto_aead_reqsize(tfm)] |
| 30 | __aligned(__alignof__(struct aead_request)); |
| 31 | struct aead_request *aead_req = (void *)aead_req_data; |
| 32 | u8 zero[GMAC_MIC_LEN], iv[AES_BLOCK_SIZE]; |
| 33 | |
| 34 | if (data_len < GMAC_MIC_LEN) |
| 35 | return -EINVAL; |
| 36 | |
| 37 | memset(aead_req, 0, sizeof(aead_req_data)); |
| 38 | |
| 39 | memset(zero, 0, GMAC_MIC_LEN); |
| 40 | sg_init_table(sg, 3); |
| 41 | sg_set_buf(&sg[0], aad, AAD_LEN); |
| 42 | sg_set_buf(&sg[1], data, data_len - GMAC_MIC_LEN); |
| 43 | sg_set_buf(&sg[2], zero, GMAC_MIC_LEN); |
| 44 | |
| 45 | memcpy(iv, nonce, GMAC_NONCE_LEN); |
| 46 | memset(iv + GMAC_NONCE_LEN, 0, sizeof(iv) - GMAC_NONCE_LEN); |
| 47 | iv[AES_BLOCK_SIZE - 1] = 0x01; |
| 48 | |
| 49 | sg_init_table(ct, 1); |
| 50 | sg_set_buf(&ct[0], mic, GMAC_MIC_LEN); |
| 51 | |
| 52 | aead_request_set_tfm(aead_req, tfm); |
| 53 | aead_request_set_assoc(aead_req, sg, AAD_LEN + data_len); |
| 54 | aead_request_set_crypt(aead_req, NULL, ct, 0, iv); |
| 55 | |
| 56 | crypto_aead_encrypt(aead_req); |
| 57 | |
| 58 | return 0; |
| 59 | } |
| 60 | |
| 61 | struct crypto_aead *ieee80211_aes_gmac_key_setup(const u8 key[], |
| 62 | size_t key_len) |
| 63 | { |
| 64 | struct crypto_aead *tfm; |
| 65 | int err; |
| 66 | |
| 67 | tfm = crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC); |
| 68 | if (IS_ERR(tfm)) |
| 69 | return tfm; |
| 70 | |
| 71 | err = crypto_aead_setkey(tfm, key, key_len); |
| 72 | if (!err) |
| 73 | return tfm; |
| 74 | if (!err) |
| 75 | err = crypto_aead_setauthsize(tfm, GMAC_MIC_LEN); |
| 76 | |
| 77 | crypto_free_aead(tfm); |
| 78 | return ERR_PTR(err); |
| 79 | } |
| 80 | |
| 81 | void ieee80211_aes_gmac_key_free(struct crypto_aead *tfm) |
| 82 | { |
| 83 | crypto_free_aead(tfm); |
| 84 | } |