source: mainline/uspace/lib/ieee80211/src/ieee80211_impl.c@ db51a6a6

/*
 * Copyright (c) 2015 Jan Kolarik
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/** @addtogroup libieee80211
 * @{
 */

/** @file ieee80211_impl.c
 *
 * IEEE 802.11 default device functions implementation.
 */

#include <stdio.h>
#include <crypto.h>
#include <stdlib.h>
#include <errno.h>
#include <ieee80211_impl.h>

/** Default implementation of IEEE802.11 start function.
 *
 * @param ieee80211_dev Structure of IEEE802.11 device.
 *
 * @return EOK.
 *
 */
int ieee80211_start_impl(ieee80211_dev_t *ieee80211_dev)
{
        return EOK;
}

/** Default implementation of IEEE802.11 TX handler function.
 *
 * @param ieee80211_dev Structure of IEEE802.11 device.
 * @param buffer        Buffer with data to send.
 * @param buffer_size   Size of buffer.
 *
 * @return EOK.
 *
 */
int ieee80211_tx_handler_impl(ieee80211_dev_t *ieee80211_dev, void *buffer,
    size_t buffer_size)
{
        return EOK;
}

/** Default implementation of IEEE802.11 set frequency function.
 *
 * @param ieee80211_dev Structure of IEEE802.11 device.
 * @param freq          Value of frequency to be switched on.
 *
 * @return EOK.
 *
 */
int ieee80211_set_freq_impl(ieee80211_dev_t *ieee80211_dev, uint16_t freq)
{
        return EOK;
}

/** Default implementation of IEEE802.11 BSSID change function.
 *
 * @param ieee80211_dev Structure of IEEE802.11 device.
 *
 * @return EOK.
 *
 */
int ieee80211_bssid_change_impl(ieee80211_dev_t *ieee80211_dev,
    bool connected)
{
        return EOK;
}

/** Default implementation of IEEE802.11 key config function.
 *
 * @param ieee80211_dev Structure of IEEE802.11 device.
 *
 * @return EOK.
 *
 */
int ieee80211_key_config_impl(ieee80211_dev_t *ieee80211_dev,
    ieee80211_key_config_t *key_conf, bool insert)
{
        return EOK;
}

/** Default implementation of IEEE802.11 scan function.
 *
 * @param ieee80211_dev Structure of IEEE802.11 device.
 * @param clear         Whether to clear current scan results.
 *
 * @return EOK if succeed, negative error code otherwise.
 *
 */
int ieee80211_scan_impl(ieee80211_dev_t *ieee80211_dev)
{
        fibril_mutex_lock(&ieee80211_dev->scan_mutex);
        
        if (ieee80211_get_auth_phase(ieee80211_dev) ==
            IEEE80211_AUTH_DISCONNECTED) {
                fibril_mutex_lock(&ieee80211_dev->ap_list.results_mutex);
                
                /* Remove old entries we don't receive beacons from. */
                ieee80211_scan_result_list_t *result_list =
                    &ieee80211_dev->ap_list;
                
                list_foreach_safe(result_list->list, cur_link, next_link) {
                        ieee80211_scan_result_link_t *cur_result =
                            list_get_instance(cur_link,
                            ieee80211_scan_result_link_t, link);
                        
                        if ((time(NULL) - cur_result->last_beacon) >
                            MAX_KEEP_SCAN_SPAN_SEC)
                                ieee80211_scan_result_list_remove(result_list,
                                    cur_result);
                }
                
                fibril_mutex_unlock(&ieee80211_dev->ap_list.results_mutex);
                
                uint16_t orig_freq = ieee80211_dev->current_freq;
                
                for (uint16_t freq = IEEE80211_FIRST_FREQ;
                    freq <= IEEE80211_MAX_FREQ; freq += IEEE80211_CHANNEL_GAP) {
                        if (ieee80211_pending_connect_request(ieee80211_dev))
                                break;
                        
                        ieee80211_dev->ops->set_freq(ieee80211_dev, freq);
                        ieee80211_probe_request(ieee80211_dev, NULL);
                        
                        /* Wait for probe responses. */
                        async_usleep(SCAN_CHANNEL_WAIT_USEC);
                }
                
                ieee80211_dev->ops->set_freq(ieee80211_dev, orig_freq);
        }
        
        fibril_mutex_unlock(&ieee80211_dev->scan_mutex);
        
        return EOK;
}

/** Pseudorandom function used for IEEE 802.11 pairwise key computation.
 *
 * Using SHA1 hash algorithm.
 *
 * @param key         Key with PBKDF2 encrypted passphrase.
 * @param data        Concatenated sequence of both MAC
 *                    addresses and nonces.
 * @param hash        Output parameter for result hash.
 * @param output_size Length of output sequence to be generated.
 *
 * @return EINVAL when key or data not specified,
 *         ENOMEM when pointer for output hash result
 *         is not allocated, otherwise EOK.
 *
 */
int ieee80211_prf(uint8_t *key, uint8_t *data, uint8_t *hash,
    size_t output_size)
{
        if ((!key) || (!data))
                return EINVAL;
        
        if (!hash)
                return ENOMEM;
        
        size_t iters = ((output_size * 8) + 159) / 160;
        
        const char *a = "Pairwise key expansion";
        uint8_t result[HASH_SHA1 * iters];
        uint8_t temp[HASH_SHA1];
        
        size_t data_size = PRF_CRYPT_DATA_LENGTH + str_size(a) + 2;
        uint8_t work_arr[data_size];
        memset(work_arr, 0, data_size);
        
        memcpy(work_arr, a, str_size(a));
        memcpy(work_arr + str_size(a) + 1, data, PRF_CRYPT_DATA_LENGTH);
        
        for (uint8_t i = 0; i < iters; i++) {
                memcpy(work_arr + data_size - 1, &i, 1);
                hmac(key, PBKDF2_KEY_LENGTH, work_arr, data_size, temp,
                    HASH_SHA1);
                memcpy(result + i*HASH_SHA1, temp, HASH_SHA1);
        }
        
        memcpy(hash, result, output_size);
        
        return EOK;
}

int ieee80211_rc4_key_unwrap(uint8_t *key, uint8_t *data, size_t data_size,
    uint8_t *output)
{
        return rc4(key, 32, data, data_size, 256, output);
}

int ieee80211_aes_key_unwrap(uint8_t *kek, uint8_t *data, size_t data_size,
    uint8_t *output)
{
        if ((!kek) || (!data))
                return EINVAL;
        
        if (!output)
                return ENOMEM;
        
        uint32_t n = data_size / 8 - 1;
        uint8_t work_data[n * 8];
        uint8_t work_input[AES_CIPHER_LENGTH];
        uint8_t work_output[AES_CIPHER_LENGTH];
        uint8_t *work_block;
        uint8_t a[8];
        
        memcpy(a, data, 8);
        
        uint64_t mask = 0xff;
        uint8_t shift, shb;
        
        memcpy(work_data, data + 8, n * 8);
        for (int j = 5; j >= 0; j--) {
                for (int i = n; i > 0; i--) {
                        for (size_t k = 0; k < 8; k++) {
                                shift = 56 - 8 * k;
                                shb = ((n * j + i) & (mask << shift)) >> shift;
                                a[k] ^= shb;
                        }
                        
                        work_block = work_data + (i - 1) * 8;
                        memcpy(work_input, a, 8);
                        memcpy(work_input + 8, work_block, 8);
                        aes_decrypt(kek, work_input, work_output);
                        memcpy(a, work_output, 8);
                        memcpy(work_data + (i - 1) * 8, work_output + 8, 8);
                }
        }
        
        size_t it;
        for (it = 0; it < 8; it++) {
                if (a[it] != 0xa6)
                        break;
        }
        
        if (it == 8) {
                memcpy(output, work_data, n * 8);
                return EOK;
        }
        
        return EINVAL;
}

static void ieee80211_michael_mic_block(uint32_t *l, uint32_t *r,
    uint32_t value)
{
        *l ^= value;
        *r ^= rotl_uint32(*l, 17);
        *l += *r;
        *r ^= ((*l & 0x00ff00ff) << 8) | ((*l & 0xff00ff00) >> 8);
        *l += *r;
        *r ^= rotl_uint32(*l, 3);
        *l += *r;
        *r ^= rotr_uint32(*l, 2);
        *l += *r;
}

int ieee80211_michael_mic(uint8_t *key, uint8_t *buffer, size_t size,
    uint8_t *mic)
{
        if ((!key) || (!buffer))
                return EINVAL;
        
        if (!mic)
                return ENOMEM;
        
        uint32_t l = uint32le_from_seq(key);
        uint32_t r = uint32le_from_seq(key + 4);
        
        ieee80211_data_header_t *data_header =
            (ieee80211_data_header_t *) buffer;
        
        uint8_t *data = buffer + sizeof(ieee80211_data_header_t) +
            IEEE80211_TKIP_HEADER_LENGTH;
        size_t data_size = size - sizeof(ieee80211_data_header_t) -
            IEEE80211_TKIP_HEADER_LENGTH;
        
        /* Process header. */
        uint8_t *src_addr =
            ieee80211_is_fromds_frame(data_header->frame_ctrl) ?
            data_header->address3 : data_header->address2;
        uint8_t *dest_addr =
            ieee80211_is_tods_frame(data_header->frame_ctrl) ?
            data_header->address3 : data_header->address1;
        
        ieee80211_michael_mic_block(&l, &r, uint32le_from_seq(dest_addr));
        ieee80211_michael_mic_block(&l, &r,
            uint16le_from_seq(dest_addr + 4) |
            (uint16le_from_seq(src_addr) << 16));
        ieee80211_michael_mic_block(&l, &r, uint32le_from_seq(src_addr + 2));
        ieee80211_michael_mic_block(&l, &r, 0);
        
        /* Process data. */
        size_t blocks = data_size / 4;
        size_t pad = data_size % 4;
        
        for (size_t k = 0; k < blocks; k++) {
                ieee80211_michael_mic_block(&l, &r,
                    uint32le_from_seq(&data[k * 4]));
        }
        
        /* Add padding. */
        uint32_t value = 0x5a;
        for (size_t i = pad; i > 0; i--) {
                value <<= 8;
                value |= data[blocks * 4 + (i - 1)];
        }
        
        ieee80211_michael_mic_block(&l, &r, value);
        ieee80211_michael_mic_block(&l, &r, 0);
        
        l = host2uint32_t_le(l);
        r = host2uint32_t_le(r);
        
        memcpy(mic, &l, 4);
        memcpy(mic + 4, &r, 4);
        
        return EOK;
}

uint16_t uint16le_from_seq(void *seq)
{
        uint16_t *u16 = (uint16_t *) seq;
        return uint16_t_le2host(*u16);
}

uint32_t uint32le_from_seq(void *seq)
{
        uint32_t *u32 = (uint32_t *) seq;
        return uint32_t_le2host(*u32);
}

uint16_t uint16be_from_seq(void *seq)
{
        uint16_t *u16 = (uint16_t *) seq;
        return uint16_t_be2host(*u16);
}

uint32_t uint32be_from_seq(void *seq)
{
        uint32_t *u32 = (uint32_t *) seq;
        return uint32_t_be2host(*u32);
}

int rnd_sequence(uint8_t *sequence, size_t length)
{
        if (!sequence)
                return ENOMEM;
        
        for (size_t i = 0; i < length; i++)
                sequence[i] = (uint8_t) rand();
        
        return EOK;
}

uint8_t *min_sequence(uint8_t *seq1, uint8_t *seq2, size_t size)
{
        if ((!seq1) || (!seq2))
                return NULL;
        
        for (size_t i = 0; i < size; i++) {
                if (seq1[i] < seq2[i])
                        return seq1;
                else if (seq1[i] > seq2[i])
                        return seq2;
        }
        
        return seq1;
}

uint8_t *max_sequence(uint8_t *seq1, uint8_t *seq2, size_t size)
{
        uint8_t *min = min_sequence(seq1, seq2, size);
        if (min == seq1)
                return seq2;
        
        return seq1;
}

/** @}
 */