mac80211: FILS AEAD protection for station mode association frames
This adds support for encrypting (Re)Association Request frame and decryption (Re)Association Response frame when using FILS in station mode. Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Jouni Malinen
Johannes Berg
Родитель
dbc0c2cb2f
Коммит
39404feee6
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@ -19,6 +19,7 @@ mac80211-y := \
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aes_gcm.o \
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aes_cmac.o \
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aes_gmac.o \
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fils_aead.o \
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cfg.o \
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ethtool.o \
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rx.o \
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@ -23,7 +23,7 @@
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#define AAD_LEN 20
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static void gf_mulx(u8 *pad)
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void gf_mulx(u8 *pad)
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{
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int i, carry;
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@ -35,9 +35,9 @@ static void gf_mulx(u8 *pad)
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pad[AES_BLOCK_SIZE - 1] ^= 0x87;
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}
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static void aes_cmac_vector(struct crypto_cipher *tfm, size_t num_elem,
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const u8 *addr[], const size_t *len, u8 *mac,
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size_t mac_len)
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void aes_cmac_vector(struct crypto_cipher *tfm, size_t num_elem,
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const u8 *addr[], const size_t *len, u8 *mac,
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size_t mac_len)
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{
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u8 cbc[AES_BLOCK_SIZE], pad[AES_BLOCK_SIZE];
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const u8 *pos, *end;
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@ -11,6 +11,10 @@
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#include <linux/crypto.h>
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void gf_mulx(u8 *pad);
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void aes_cmac_vector(struct crypto_cipher *tfm, size_t num_elem,
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const u8 *addr[], const size_t *len, u8 *mac,
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size_t mac_len);
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struct crypto_cipher *ieee80211_aes_cmac_key_setup(const u8 key[],
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size_t key_len);
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void ieee80211_aes_cmac(struct crypto_cipher *tfm, const u8 *aad,
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@ -0,0 +1,344 @@
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/*
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* FILS AEAD for (Re)Association Request/Response frames
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* Copyright 2016, 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 <crypto/aes.h>
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#include <crypto/algapi.h>
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#include <crypto/skcipher.h>
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#include "ieee80211_i.h"
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#include "aes_cmac.h"
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#include "fils_aead.h"
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static int aes_s2v(struct crypto_cipher *tfm,
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size_t num_elem, const u8 *addr[], size_t len[], u8 *v)
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{
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u8 d[AES_BLOCK_SIZE], tmp[AES_BLOCK_SIZE];
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size_t i;
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const u8 *data[2];
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size_t data_len[2], data_elems;
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/* D = AES-CMAC(K, <zero>) */
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memset(tmp, 0, AES_BLOCK_SIZE);
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data[0] = tmp;
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data_len[0] = AES_BLOCK_SIZE;
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aes_cmac_vector(tfm, 1, data, data_len, d, AES_BLOCK_SIZE);
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for (i = 0; i < num_elem - 1; i++) {
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/* D = dbl(D) xor AES_CMAC(K, Si) */
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gf_mulx(d); /* dbl */
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aes_cmac_vector(tfm, 1, &addr[i], &len[i], tmp,
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AES_BLOCK_SIZE);
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crypto_xor(d, tmp, AES_BLOCK_SIZE);
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}
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if (len[i] >= AES_BLOCK_SIZE) {
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/* len(Sn) >= 128 */
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size_t j;
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const u8 *pos;
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/* T = Sn xorend D */
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/* Use a temporary buffer to perform xorend on Sn (addr[i]) to
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* avoid modifying the const input argument.
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*/
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data[0] = addr[i];
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data_len[0] = len[i] - AES_BLOCK_SIZE;
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pos = addr[i] + data_len[0];
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for (j = 0; j < AES_BLOCK_SIZE; j++)
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tmp[j] = pos[j] ^ d[j];
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data[1] = tmp;
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data_len[1] = AES_BLOCK_SIZE;
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data_elems = 2;
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} else {
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/* len(Sn) < 128 */
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/* T = dbl(D) xor pad(Sn) */
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gf_mulx(d); /* dbl */
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memset(tmp, 0, AES_BLOCK_SIZE);
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memcpy(tmp, addr[i], len[i]);
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tmp[len[i]] = 0x80;
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crypto_xor(d, tmp, AES_BLOCK_SIZE);
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data[0] = d;
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data_len[0] = sizeof(d);
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data_elems = 1;
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}
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/* V = AES-CMAC(K, T) */
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aes_cmac_vector(tfm, data_elems, data, data_len, v, AES_BLOCK_SIZE);
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return 0;
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}
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/* Note: addr[] and len[] needs to have one extra slot at the end. */
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static int aes_siv_encrypt(const u8 *key, size_t key_len,
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const u8 *plain, size_t plain_len,
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size_t num_elem, const u8 *addr[],
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size_t len[], u8 *out)
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{
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u8 v[AES_BLOCK_SIZE];
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struct crypto_cipher *tfm;
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struct crypto_skcipher *tfm2;
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struct skcipher_request *req;
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int res;
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struct scatterlist src[1], dst[1];
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u8 *tmp;
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key_len /= 2; /* S2V key || CTR key */
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addr[num_elem] = plain;
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len[num_elem] = plain_len;
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num_elem++;
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/* S2V */
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tfm = crypto_alloc_cipher("aes", 0, 0);
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if (IS_ERR(tfm))
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return PTR_ERR(tfm);
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/* K1 for S2V */
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res = crypto_cipher_setkey(tfm, key, key_len);
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if (!res)
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res = aes_s2v(tfm, num_elem, addr, len, v);
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crypto_free_cipher(tfm);
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if (res)
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return res;
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/* Use a temporary buffer of the plaintext to handle need for
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* overwriting this during AES-CTR.
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*/
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tmp = kmemdup(plain, plain_len, GFP_KERNEL);
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if (!tmp) {
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res = -ENOMEM;
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goto fail;
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}
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/* IV for CTR before encrypted data */
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memcpy(out, v, AES_BLOCK_SIZE);
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/* Synthetic IV to be used as the initial counter in CTR:
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* Q = V bitand (1^64 || 0^1 || 1^31 || 0^1 || 1^31)
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*/
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v[8] &= 0x7f;
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v[12] &= 0x7f;
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/* CTR */
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tfm2 = crypto_alloc_skcipher("ctr(aes)", 0, 0);
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if (IS_ERR(tfm2)) {
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kfree(tmp);
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return PTR_ERR(tfm2);
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}
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/* K2 for CTR */
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res = crypto_skcipher_setkey(tfm2, key + key_len, key_len);
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if (res)
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goto fail;
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req = skcipher_request_alloc(tfm2, GFP_KERNEL);
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if (!req) {
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res = -ENOMEM;
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goto fail;
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}
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sg_init_one(src, tmp, plain_len);
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sg_init_one(dst, out + AES_BLOCK_SIZE, plain_len);
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skcipher_request_set_crypt(req, src, dst, plain_len, v);
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res = crypto_skcipher_encrypt(req);
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skcipher_request_free(req);
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fail:
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kfree(tmp);
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crypto_free_skcipher(tfm2);
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return res;
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}
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/* Note: addr[] and len[] needs to have one extra slot at the end. */
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static int aes_siv_decrypt(const u8 *key, size_t key_len,
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const u8 *iv_crypt, size_t iv_c_len,
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size_t num_elem, const u8 *addr[], size_t len[],
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u8 *out)
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{
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struct crypto_cipher *tfm;
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struct crypto_skcipher *tfm2;
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struct skcipher_request *req;
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struct scatterlist src[1], dst[1];
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size_t crypt_len;
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int res;
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u8 frame_iv[AES_BLOCK_SIZE], iv[AES_BLOCK_SIZE];
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u8 check[AES_BLOCK_SIZE];
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crypt_len = iv_c_len - AES_BLOCK_SIZE;
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key_len /= 2; /* S2V key || CTR key */
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addr[num_elem] = out;
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len[num_elem] = crypt_len;
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num_elem++;
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memcpy(iv, iv_crypt, AES_BLOCK_SIZE);
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memcpy(frame_iv, iv_crypt, AES_BLOCK_SIZE);
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/* Synthetic IV to be used as the initial counter in CTR:
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* Q = V bitand (1^64 || 0^1 || 1^31 || 0^1 || 1^31)
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*/
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iv[8] &= 0x7f;
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iv[12] &= 0x7f;
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/* CTR */
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tfm2 = crypto_alloc_skcipher("ctr(aes)", 0, 0);
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if (IS_ERR(tfm2))
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return PTR_ERR(tfm2);
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/* K2 for CTR */
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res = crypto_skcipher_setkey(tfm2, key + key_len, key_len);
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if (res) {
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crypto_free_skcipher(tfm2);
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return res;
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}
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req = skcipher_request_alloc(tfm2, GFP_KERNEL);
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if (!req) {
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crypto_free_skcipher(tfm2);
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return -ENOMEM;
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}
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sg_init_one(src, iv_crypt + AES_BLOCK_SIZE, crypt_len);
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sg_init_one(dst, out, crypt_len);
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skcipher_request_set_crypt(req, src, dst, crypt_len, iv);
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res = crypto_skcipher_decrypt(req);
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skcipher_request_free(req);
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crypto_free_skcipher(tfm2);
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if (res)
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return res;
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/* S2V */
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tfm = crypto_alloc_cipher("aes", 0, 0);
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if (IS_ERR(tfm))
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return PTR_ERR(tfm);
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/* K1 for S2V */
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res = crypto_cipher_setkey(tfm, key, key_len);
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if (!res)
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res = aes_s2v(tfm, num_elem, addr, len, check);
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crypto_free_cipher(tfm);
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if (res)
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return res;
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if (memcmp(check, frame_iv, AES_BLOCK_SIZE) != 0)
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return -EINVAL;
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return 0;
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}
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int fils_encrypt_assoc_req(struct sk_buff *skb,
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struct ieee80211_mgd_assoc_data *assoc_data)
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{
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struct ieee80211_mgmt *mgmt = (void *)skb->data;
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u8 *capab, *ies, *encr;
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const u8 *addr[5 + 1], *session;
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size_t len[5 + 1];
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size_t crypt_len;
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if (ieee80211_is_reassoc_req(mgmt->frame_control)) {
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capab = (u8 *)&mgmt->u.reassoc_req.capab_info;
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ies = mgmt->u.reassoc_req.variable;
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} else {
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capab = (u8 *)&mgmt->u.assoc_req.capab_info;
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ies = mgmt->u.assoc_req.variable;
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}
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session = cfg80211_find_ext_ie(WLAN_EID_EXT_FILS_SESSION,
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ies, skb->data + skb->len - ies);
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if (!session || session[1] != 1 + 8)
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return -EINVAL;
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/* encrypt after FILS Session element */
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encr = (u8 *)session + 2 + 1 + 8;
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/* AES-SIV AAD vectors */
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/* The STA's MAC address */
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addr[0] = mgmt->sa;
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len[0] = ETH_ALEN;
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/* The AP's BSSID */
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addr[1] = mgmt->da;
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len[1] = ETH_ALEN;
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/* The STA's nonce */
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addr[2] = assoc_data->fils_nonces;
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len[2] = FILS_NONCE_LEN;
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/* The AP's nonce */
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addr[3] = &assoc_data->fils_nonces[FILS_NONCE_LEN];
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len[3] = FILS_NONCE_LEN;
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/* The (Re)Association Request frame from the Capability Information
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* field to the FILS Session element (both inclusive).
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*/
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addr[4] = capab;
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len[4] = encr - capab;
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crypt_len = skb->data + skb->len - encr;
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skb_put(skb, AES_BLOCK_SIZE);
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return aes_siv_encrypt(assoc_data->fils_kek, assoc_data->fils_kek_len,
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encr, crypt_len, 1, addr, len, encr);
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}
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int fils_decrypt_assoc_resp(struct ieee80211_sub_if_data *sdata,
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u8 *frame, size_t *frame_len,
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struct ieee80211_mgd_assoc_data *assoc_data)
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{
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struct ieee80211_mgmt *mgmt = (void *)frame;
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u8 *capab, *ies, *encr;
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const u8 *addr[5 + 1], *session;
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size_t len[5 + 1];
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int res;
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size_t crypt_len;
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if (*frame_len < 24 + 6)
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return -EINVAL;
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capab = (u8 *)&mgmt->u.assoc_resp.capab_info;
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ies = mgmt->u.assoc_resp.variable;
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session = cfg80211_find_ext_ie(WLAN_EID_EXT_FILS_SESSION,
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ies, frame + *frame_len - ies);
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if (!session || session[1] != 1 + 8) {
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mlme_dbg(sdata,
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"No (valid) FILS Session element in (Re)Association Response frame from %pM",
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mgmt->sa);
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return -EINVAL;
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}
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/* decrypt after FILS Session element */
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encr = (u8 *)session + 2 + 1 + 8;
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/* AES-SIV AAD vectors */
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/* The AP's BSSID */
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addr[0] = mgmt->sa;
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len[0] = ETH_ALEN;
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/* The STA's MAC address */
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addr[1] = mgmt->da;
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len[1] = ETH_ALEN;
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/* The AP's nonce */
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addr[2] = &assoc_data->fils_nonces[FILS_NONCE_LEN];
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len[2] = FILS_NONCE_LEN;
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/* The STA's nonce */
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addr[3] = assoc_data->fils_nonces;
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len[3] = FILS_NONCE_LEN;
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/* The (Re)Association Response frame from the Capability Information
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* field to the FILS Session element (both inclusive).
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*/
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addr[4] = capab;
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len[4] = encr - capab;
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crypt_len = frame + *frame_len - encr;
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if (crypt_len < AES_BLOCK_SIZE) {
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mlme_dbg(sdata,
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"Not enough room for AES-SIV data after FILS Session element in (Re)Association Response frame from %pM",
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mgmt->sa);
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return -EINVAL;
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}
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res = aes_siv_decrypt(assoc_data->fils_kek, assoc_data->fils_kek_len,
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encr, crypt_len, 5, addr, len, encr);
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if (res != 0) {
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mlme_dbg(sdata,
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"AES-SIV decryption of (Re)Association Response frame from %pM failed",
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mgmt->sa);
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return res;
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}
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*frame_len -= AES_BLOCK_SIZE;
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return 0;
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}
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|
|
@ -0,0 +1,19 @@
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/*
|
||||
* FILS AEAD for (Re)Association Request/Response frames
|
||||
* Copyright 2016, Qualcomm Atheros, Inc.
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License version 2 as
|
||||
* published by the Free Software Foundation.
|
||||
*/
|
||||
|
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#ifndef FILS_AEAD_H
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#define FILS_AEAD_H
|
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int fils_encrypt_assoc_req(struct sk_buff *skb,
|
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struct ieee80211_mgd_assoc_data *assoc_data);
|
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int fils_decrypt_assoc_resp(struct ieee80211_sub_if_data *sdata,
|
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u8 *frame, size_t *frame_len,
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struct ieee80211_mgd_assoc_data *assoc_data);
|
||||
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#endif /* FILS_AEAD_H */
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|
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@ -401,6 +401,10 @@ struct ieee80211_mgd_assoc_data {
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|
||||
struct ieee80211_vht_cap ap_vht_cap;
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|
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u8 fils_nonces[2 * FILS_NONCE_LEN];
|
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u8 fils_kek[FILS_MAX_KEK_LEN];
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size_t fils_kek_len;
|
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|
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size_t ie_len;
|
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u8 ie[];
|
||||
};
|
||||
|
|
|
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|
|
@ -30,6 +30,7 @@
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|||
#include "driver-ops.h"
|
||||
#include "rate.h"
|
||||
#include "led.h"
|
||||
#include "fils_aead.h"
|
||||
|
||||
#define IEEE80211_AUTH_TIMEOUT (HZ / 5)
|
||||
#define IEEE80211_AUTH_TIMEOUT_LONG (HZ / 2)
|
||||
|
|
@ -652,6 +653,7 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
|
|||
2 + sizeof(struct ieee80211_ht_cap) + /* HT */
|
||||
2 + sizeof(struct ieee80211_vht_cap) + /* VHT */
|
||||
assoc_data->ie_len + /* extra IEs */
|
||||
(assoc_data->fils_kek_len ? 16 /* AES-SIV */ : 0) +
|
||||
9, /* WMM */
|
||||
GFP_KERNEL);
|
||||
if (!skb)
|
||||
|
|
@ -875,6 +877,12 @@ static void ieee80211_send_assoc(struct ieee80211_sub_if_data *sdata)
|
|||
memcpy(pos, assoc_data->ie + offset, noffset - offset);
|
||||
}
|
||||
|
||||
if (assoc_data->fils_kek_len &&
|
||||
fils_encrypt_assoc_req(skb, assoc_data) < 0) {
|
||||
dev_kfree_skb(skb);
|
||||
return;
|
||||
}
|
||||
|
||||
drv_mgd_prepare_tx(local, sdata);
|
||||
|
||||
IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
|
||||
|
|
@ -3146,6 +3154,10 @@ static void ieee80211_rx_mgmt_assoc_resp(struct ieee80211_sub_if_data *sdata,
|
|||
reassoc ? "Rea" : "A", mgmt->sa,
|
||||
capab_info, status_code, (u16)(aid & ~(BIT(15) | BIT(14))));
|
||||
|
||||
if (assoc_data->fils_kek_len &&
|
||||
fils_decrypt_assoc_resp(sdata, (u8 *)mgmt, &len, assoc_data) < 0)
|
||||
return;
|
||||
|
||||
pos = mgmt->u.assoc_resp.variable;
|
||||
ieee802_11_parse_elems(pos, len - (pos - (u8 *) mgmt), false, &elems);
|
||||
|
||||
|
|
@ -4707,6 +4719,21 @@ int ieee80211_mgd_assoc(struct ieee80211_sub_if_data *sdata,
|
|||
assoc_data->ie_len = req->ie_len;
|
||||
}
|
||||
|
||||
if (req->fils_kek) {
|
||||
/* should already be checked in cfg80211 - so warn */
|
||||
if (WARN_ON(req->fils_kek_len > FILS_MAX_KEK_LEN)) {
|
||||
err = -EINVAL;
|
||||
goto err_free;
|
||||
}
|
||||
memcpy(assoc_data->fils_kek, req->fils_kek,
|
||||
req->fils_kek_len);
|
||||
assoc_data->fils_kek_len = req->fils_kek_len;
|
||||
}
|
||||
|
||||
if (req->fils_nonces)
|
||||
memcpy(assoc_data->fils_nonces, req->fils_nonces,
|
||||
2 * FILS_NONCE_LEN);
|
||||
|
||||
assoc_data->bss = req->bss;
|
||||
|
||||
if (ifmgd->req_smps == IEEE80211_SMPS_AUTOMATIC) {
|
||||
|
|
|
|||
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