mac80211: port CCMP to cryptoapi's CCM driver
Use the generic CCM aead chaining mode driver rather than a local implementation that sits right on top of the core AES cipher. This allows the use of accelerated implementations of either CCM as a whole or the CTR mode which it encapsulates. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Ard Biesheuvel
Johannes Berg
parent
fa1fb9cb1c
commit
7ec7c4a9a6
5 changed files with 80 additions and 142 deletions
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@ -4,6 +4,7 @@ config MAC80211
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select CRYPTO
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select CRYPTO_ARC4
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select CRYPTO_AES
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select CRYPTO_CCM
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select CRC32
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select AVERAGE
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---help---
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@ -2,6 +2,8 @@
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* Copyright 2003-2004, Instant802 Networks, Inc.
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* Copyright 2005-2006, Devicescape Software, Inc.
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*
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* Rewrite: Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
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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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@ -17,134 +19,75 @@
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#include "key.h"
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#include "aes_ccm.h"
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static void aes_ccm_prepare(struct crypto_cipher *tfm, u8 *scratch, u8 *a)
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void ieee80211_aes_ccm_encrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
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u8 *data, size_t data_len, u8 *mic)
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{
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int i;
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u8 *b_0, *aad, *b, *s_0;
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struct scatterlist assoc, pt, ct[2];
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struct {
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struct aead_request req;
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u8 priv[crypto_aead_reqsize(tfm)];
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} aead_req;
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b_0 = scratch + 3 * AES_BLOCK_SIZE;
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aad = scratch + 4 * AES_BLOCK_SIZE;
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b = scratch;
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s_0 = scratch + AES_BLOCK_SIZE;
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memset(&aead_req, 0, sizeof(aead_req));
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crypto_cipher_encrypt_one(tfm, b, b_0);
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sg_init_one(&pt, data, data_len);
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sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
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sg_init_table(ct, 2);
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sg_set_buf(&ct[0], data, data_len);
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sg_set_buf(&ct[1], mic, IEEE80211_CCMP_MIC_LEN);
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/* Extra Authenticate-only data (always two AES blocks) */
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for (i = 0; i < AES_BLOCK_SIZE; i++)
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aad[i] ^= b[i];
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crypto_cipher_encrypt_one(tfm, b, aad);
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aead_request_set_tfm(&aead_req.req, tfm);
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aead_request_set_assoc(&aead_req.req, &assoc, assoc.length);
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aead_request_set_crypt(&aead_req.req, &pt, ct, data_len, b_0);
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aad += AES_BLOCK_SIZE;
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for (i = 0; i < AES_BLOCK_SIZE; i++)
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aad[i] ^= b[i];
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crypto_cipher_encrypt_one(tfm, a, aad);
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/* Mask out bits from auth-only-b_0 */
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b_0[0] &= 0x07;
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/* S_0 is used to encrypt T (= MIC) */
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b_0[14] = 0;
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b_0[15] = 0;
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crypto_cipher_encrypt_one(tfm, s_0, b_0);
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crypto_aead_encrypt(&aead_req.req);
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}
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void ieee80211_aes_ccm_encrypt(struct crypto_cipher *tfm, u8 *scratch,
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u8 *data, size_t data_len,
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u8 *cdata, u8 *mic)
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int ieee80211_aes_ccm_decrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
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u8 *data, size_t data_len, u8 *mic)
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{
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int i, j, last_len, num_blocks;
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u8 *pos, *cpos, *b, *s_0, *e, *b_0;
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struct scatterlist assoc, pt, ct[2];
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struct {
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struct aead_request req;
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u8 priv[crypto_aead_reqsize(tfm)];
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} aead_req;
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b = scratch;
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s_0 = scratch + AES_BLOCK_SIZE;
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e = scratch + 2 * AES_BLOCK_SIZE;
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b_0 = scratch + 3 * AES_BLOCK_SIZE;
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memset(&aead_req, 0, sizeof(aead_req));
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num_blocks = DIV_ROUND_UP(data_len, AES_BLOCK_SIZE);
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last_len = data_len % AES_BLOCK_SIZE;
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aes_ccm_prepare(tfm, scratch, b);
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sg_init_one(&pt, data, data_len);
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sg_init_one(&assoc, &aad[2], be16_to_cpup((__be16 *)aad));
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sg_init_table(ct, 2);
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sg_set_buf(&ct[0], data, data_len);
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sg_set_buf(&ct[1], mic, IEEE80211_CCMP_MIC_LEN);
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/* Process payload blocks */
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pos = data;
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cpos = cdata;
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for (j = 1; j <= num_blocks; j++) {
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int blen = (j == num_blocks && last_len) ?
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last_len : AES_BLOCK_SIZE;
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aead_request_set_tfm(&aead_req.req, tfm);
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aead_request_set_assoc(&aead_req.req, &assoc, assoc.length);
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aead_request_set_crypt(&aead_req.req, ct, &pt,
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data_len + IEEE80211_CCMP_MIC_LEN, b_0);
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/* Authentication followed by encryption */
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for (i = 0; i < blen; i++)
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b[i] ^= pos[i];
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crypto_cipher_encrypt_one(tfm, b, b);
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b_0[14] = (j >> 8) & 0xff;
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b_0[15] = j & 0xff;
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crypto_cipher_encrypt_one(tfm, e, b_0);
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for (i = 0; i < blen; i++)
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*cpos++ = *pos++ ^ e[i];
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}
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for (i = 0; i < IEEE80211_CCMP_MIC_LEN; i++)
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mic[i] = b[i] ^ s_0[i];
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return crypto_aead_decrypt(&aead_req.req);
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}
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int ieee80211_aes_ccm_decrypt(struct crypto_cipher *tfm, u8 *scratch,
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u8 *cdata, size_t data_len, u8 *mic, u8 *data)
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struct crypto_aead *ieee80211_aes_key_setup_encrypt(const u8 key[])
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{
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int i, j, last_len, num_blocks;
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u8 *pos, *cpos, *b, *s_0, *a, *b_0;
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struct crypto_aead *tfm;
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int err;
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b = scratch;
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s_0 = scratch + AES_BLOCK_SIZE;
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a = scratch + 2 * AES_BLOCK_SIZE;
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b_0 = scratch + 3 * AES_BLOCK_SIZE;
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tfm = crypto_alloc_aead("ccm(aes)", 0, CRYPTO_ALG_ASYNC);
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if (IS_ERR(tfm))
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return tfm;
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num_blocks = DIV_ROUND_UP(data_len, AES_BLOCK_SIZE);
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last_len = data_len % AES_BLOCK_SIZE;
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aes_ccm_prepare(tfm, scratch, a);
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err = crypto_aead_setkey(tfm, key, WLAN_KEY_LEN_CCMP);
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if (!err)
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err = crypto_aead_setauthsize(tfm, IEEE80211_CCMP_MIC_LEN);
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if (!err)
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return tfm;
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/* Process payload blocks */
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cpos = cdata;
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pos = data;
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for (j = 1; j <= num_blocks; j++) {
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int blen = (j == num_blocks && last_len) ?
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last_len : AES_BLOCK_SIZE;
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/* Decryption followed by authentication */
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b_0[14] = (j >> 8) & 0xff;
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b_0[15] = j & 0xff;
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crypto_cipher_encrypt_one(tfm, b, b_0);
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for (i = 0; i < blen; i++) {
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*pos = *cpos++ ^ b[i];
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a[i] ^= *pos++;
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}
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crypto_cipher_encrypt_one(tfm, a, a);
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}
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for (i = 0; i < IEEE80211_CCMP_MIC_LEN; i++) {
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if ((mic[i] ^ s_0[i]) != a[i])
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return -1;
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}
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return 0;
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crypto_free_aead(tfm);
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return ERR_PTR(err);
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}
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struct crypto_cipher *ieee80211_aes_key_setup_encrypt(const u8 key[])
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void ieee80211_aes_key_free(struct crypto_aead *tfm)
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{
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struct crypto_cipher *tfm;
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tfm = crypto_alloc_cipher("aes", 0, CRYPTO_ALG_ASYNC);
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if (!IS_ERR(tfm))
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crypto_cipher_setkey(tfm, key, WLAN_KEY_LEN_CCMP);
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return tfm;
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}
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void ieee80211_aes_key_free(struct crypto_cipher *tfm)
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{
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crypto_free_cipher(tfm);
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crypto_free_aead(tfm);
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}
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@ -12,13 +12,11 @@
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#include <linux/crypto.h>
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struct crypto_cipher *ieee80211_aes_key_setup_encrypt(const u8 key[]);
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void ieee80211_aes_ccm_encrypt(struct crypto_cipher *tfm, u8 *scratch,
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u8 *data, size_t data_len,
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u8 *cdata, u8 *mic);
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int ieee80211_aes_ccm_decrypt(struct crypto_cipher *tfm, u8 *scratch,
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u8 *cdata, size_t data_len,
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u8 *mic, u8 *data);
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void ieee80211_aes_key_free(struct crypto_cipher *tfm);
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struct crypto_aead *ieee80211_aes_key_setup_encrypt(const u8 key[]);
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void ieee80211_aes_ccm_encrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
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u8 *data, size_t data_len, u8 *mic);
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int ieee80211_aes_ccm_decrypt(struct crypto_aead *tfm, u8 *b_0, u8 *aad,
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u8 *data, size_t data_len, u8 *mic);
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void ieee80211_aes_key_free(struct crypto_aead *tfm);
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#endif /* AES_CCM_H */
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@ -83,7 +83,7 @@ struct ieee80211_key {
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* Management frames.
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*/
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u8 rx_pn[IEEE80211_NUM_TIDS + 1][IEEE80211_CCMP_PN_LEN];
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struct crypto_cipher *tfm;
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struct crypto_aead *tfm;
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u32 replays; /* dot11RSNAStatsCCMPReplays */
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} ccmp;
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struct {
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@ -301,22 +301,16 @@ ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
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}
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static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
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static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *b_0, u8 *aad,
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int encrypted)
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{
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__le16 mask_fc;
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int a4_included, mgmt;
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u8 qos_tid;
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u8 *b_0, *aad;
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u16 data_len, len_a;
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u16 len_a;
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unsigned int hdrlen;
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struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
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memset(scratch, 0, 6 * AES_BLOCK_SIZE);
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b_0 = scratch + 3 * AES_BLOCK_SIZE;
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aad = scratch + 4 * AES_BLOCK_SIZE;
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/*
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* Mask FC: zero subtype b4 b5 b6 (if not mgmt)
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* Retry, PwrMgt, MoreData; set Protected
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@ -338,20 +332,21 @@ static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
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else
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qos_tid = 0;
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data_len = skb->len - hdrlen - IEEE80211_CCMP_HDR_LEN;
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if (encrypted)
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data_len -= IEEE80211_CCMP_MIC_LEN;
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/* In CCM, the initial vectors (IV) used for CTR mode encryption and CBC
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* mode authentication are not allowed to collide, yet both are derived
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* from this vector b_0. We only set L := 1 here to indicate that the
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* data size can be represented in (L+1) bytes. The CCM layer will take
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* care of storing the data length in the top (L+1) bytes and setting
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* and clearing the other bits as is required to derive the two IVs.
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*/
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b_0[0] = 0x1;
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/* First block, b_0 */
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b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
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/* Nonce: Nonce Flags | A2 | PN
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* Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
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*/
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b_0[1] = qos_tid | (mgmt << 4);
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memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
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memcpy(&b_0[8], pn, IEEE80211_CCMP_PN_LEN);
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/* l(m) */
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put_unaligned_be16(data_len, &b_0[14]);
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/* AAD (extra authenticate-only data) / masked 802.11 header
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* FC | A1 | A2 | A3 | SC | [A4] | [QC] */
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@ -407,7 +402,8 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
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u8 *pos;
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u8 pn[6];
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u64 pn64;
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u8 scratch[6 * AES_BLOCK_SIZE];
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u8 aad[2 * AES_BLOCK_SIZE];
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u8 b_0[AES_BLOCK_SIZE];
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if (info->control.hw_key &&
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!(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
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@ -460,9 +456,9 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
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return 0;
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pos += IEEE80211_CCMP_HDR_LEN;
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ccmp_special_blocks(skb, pn, scratch, 0);
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ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len,
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pos, skb_put(skb, IEEE80211_CCMP_MIC_LEN));
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ccmp_special_blocks(skb, pn, b_0, aad, 0);
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ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, b_0, aad, pos, len,
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skb_put(skb, IEEE80211_CCMP_MIC_LEN));
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return 0;
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}
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@ -525,16 +521,16 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
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}
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if (!(status->flag & RX_FLAG_DECRYPTED)) {
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u8 scratch[6 * AES_BLOCK_SIZE];
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u8 aad[2 * AES_BLOCK_SIZE];
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u8 b_0[AES_BLOCK_SIZE];
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/* hardware didn't decrypt/verify MIC */
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ccmp_special_blocks(skb, pn, scratch, 1);
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ccmp_special_blocks(skb, pn, b_0, aad, 1);
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if (ieee80211_aes_ccm_decrypt(
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key->u.ccmp.tfm, scratch,
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key->u.ccmp.tfm, b_0, aad,
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skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN,
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data_len,
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skb->data + skb->len - IEEE80211_CCMP_MIC_LEN,
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skb->data + hdrlen + IEEE80211_CCMP_HDR_LEN))
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skb->data + skb->len - IEEE80211_CCMP_MIC_LEN))
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return RX_DROP_UNUSABLE;
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}
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