93 lines
2.3 KiB
C
93 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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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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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/err.h>
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#include <crypto/aead.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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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[5];
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u8 *zero, *__aad, iv[AES_BLOCK_SIZE];
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struct aead_request *aead_req;
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int reqsize = sizeof(*aead_req) + crypto_aead_reqsize(tfm);
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const __le16 *fc;
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int ret;
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if (data_len < GMAC_MIC_LEN)
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return -EINVAL;
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aead_req = kzalloc(reqsize + GMAC_MIC_LEN + GMAC_AAD_LEN, GFP_ATOMIC);
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if (!aead_req)
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return -ENOMEM;
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zero = (u8 *)aead_req + reqsize;
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__aad = zero + GMAC_MIC_LEN;
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memcpy(__aad, aad, GMAC_AAD_LEN);
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fc = (const __le16 *)aad;
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if (ieee80211_is_beacon(*fc)) {
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/* mask Timestamp field to zero */
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sg_init_table(sg, 5);
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sg_set_buf(&sg[0], __aad, GMAC_AAD_LEN);
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sg_set_buf(&sg[1], zero, 8);
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sg_set_buf(&sg[2], data + 8, data_len - 8 - GMAC_MIC_LEN);
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sg_set_buf(&sg[3], zero, GMAC_MIC_LEN);
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sg_set_buf(&sg[4], mic, GMAC_MIC_LEN);
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} else {
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sg_init_table(sg, 4);
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sg_set_buf(&sg[0], __aad, GMAC_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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sg_set_buf(&sg[3], mic, GMAC_MIC_LEN);
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}
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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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aead_request_set_tfm(aead_req, tfm);
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aead_request_set_crypt(aead_req, sg, sg, 0, iv);
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aead_request_set_ad(aead_req, GMAC_AAD_LEN + data_len);
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ret = crypto_aead_encrypt(aead_req);
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kfree_sensitive(aead_req);
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return ret;
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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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err = crypto_aead_setauthsize(tfm, GMAC_MIC_LEN);
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if (!err)
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return tfm;
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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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