85 lines
2.1 KiB
C
85 lines
2.1 KiB
C
/*
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* AES-GMAC for IEEE 802.11 BIP-GMAC-128 and BIP-GMAC-256
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* Copyright 2015, Qualcomm Atheros, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/crypto.h>
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#include <linux/err.h>
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#include <crypto/aes.h>
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#include <net/mac80211.h>
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#include "key.h"
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#include "aes_gmac.h"
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#define GMAC_MIC_LEN 16
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#define GMAC_NONCE_LEN 12
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#define AAD_LEN 20
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int ieee80211_aes_gmac(struct crypto_aead *tfm, const u8 *aad, u8 *nonce,
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const u8 *data, size_t data_len, u8 *mic)
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{
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struct scatterlist sg[3], ct[1];
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char aead_req_data[sizeof(struct aead_request) +
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crypto_aead_reqsize(tfm)]
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__aligned(__alignof__(struct aead_request));
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struct aead_request *aead_req = (void *)aead_req_data;
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u8 zero[GMAC_MIC_LEN], iv[AES_BLOCK_SIZE];
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if (data_len < GMAC_MIC_LEN)
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return -EINVAL;
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memset(aead_req, 0, sizeof(aead_req_data));
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memset(zero, 0, GMAC_MIC_LEN);
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sg_init_table(sg, 3);
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sg_set_buf(&sg[0], aad, AAD_LEN);
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sg_set_buf(&sg[1], data, data_len - GMAC_MIC_LEN);
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sg_set_buf(&sg[2], zero, GMAC_MIC_LEN);
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memcpy(iv, nonce, GMAC_NONCE_LEN);
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memset(iv + GMAC_NONCE_LEN, 0, sizeof(iv) - GMAC_NONCE_LEN);
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iv[AES_BLOCK_SIZE - 1] = 0x01;
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sg_init_table(ct, 1);
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sg_set_buf(&ct[0], mic, GMAC_MIC_LEN);
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aead_request_set_tfm(aead_req, tfm);
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aead_request_set_assoc(aead_req, sg, AAD_LEN + data_len);
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aead_request_set_crypt(aead_req, NULL, ct, 0, iv);
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crypto_aead_encrypt(aead_req);
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return 0;
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}
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struct crypto_aead *ieee80211_aes_gmac_key_setup(const u8 key[],
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size_t key_len)
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{
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struct crypto_aead *tfm;
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int err;
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tfm = crypto_alloc_aead("gcm(aes)", 0, CRYPTO_ALG_ASYNC);
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if (IS_ERR(tfm))
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return tfm;
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err = crypto_aead_setkey(tfm, key, key_len);
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if (!err)
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return tfm;
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if (!err)
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err = crypto_aead_setauthsize(tfm, GMAC_MIC_LEN);
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crypto_free_aead(tfm);
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return ERR_PTR(err);
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}
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void ieee80211_aes_gmac_key_free(struct crypto_aead *tfm)
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{
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crypto_free_aead(tfm);
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}
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