forked from Minki/linux
681d119047
TKIP countermeasures depend on devices being able to detect Michael MIC failures on received frames and for stations to report errors to the AP. In order to test that behavior, it is useful to be able to send out TKIP frames with incorrect Michael MIC. This testing behavior has minimal effect on the TX path, so it can be added to mac80211 for convenient use. The interface for using this functionality is a file in mac80211 netdev debugfs (tkip_mic_test). Writing a MAC address to the file makes mac80211 generate a dummy data frame that will be sent out using invalid Michael MIC value. In AP mode, the address needs to be for one of the associated stations or ff:ff:ff:ff:ff:ff to use a broadcast frame. In station mode, the address can be anything, e.g., the current BSSID. It should be noted that this functionality works correctly only when associated and using TKIP. Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com> Acked-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
581 lines
14 KiB
C
581 lines
14 KiB
C
/*
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* Copyright 2002-2004, Instant802 Networks, Inc.
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* Copyright 2008, Jouni Malinen <j@w1.fi>
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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/netdevice.h>
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#include <linux/types.h>
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#include <linux/skbuff.h>
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#include <linux/compiler.h>
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#include <linux/ieee80211.h>
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#include <linux/gfp.h>
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#include <asm/unaligned.h>
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#include <net/mac80211.h>
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#include "ieee80211_i.h"
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#include "michael.h"
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#include "tkip.h"
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#include "aes_ccm.h"
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#include "aes_cmac.h"
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#include "wpa.h"
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ieee80211_tx_result
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ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx)
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{
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u8 *data, *key, *mic;
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size_t data_len;
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unsigned int hdrlen;
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struct ieee80211_hdr *hdr;
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struct sk_buff *skb = tx->skb;
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struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
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int tail;
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hdr = (struct ieee80211_hdr *)skb->data;
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if (!tx->key || tx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
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skb->len < 24 || !ieee80211_is_data_present(hdr->frame_control))
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return TX_CONTINUE;
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hdrlen = ieee80211_hdrlen(hdr->frame_control);
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if (skb->len < hdrlen)
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return TX_DROP;
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data = skb->data + hdrlen;
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data_len = skb->len - hdrlen;
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if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE)) {
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/* Need to use software crypto for the test */
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info->control.hw_key = NULL;
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}
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if (info->control.hw_key &&
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!(tx->flags & IEEE80211_TX_FRAGMENTED) &&
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!(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
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/* hwaccel - with no need for SW-generated MMIC */
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return TX_CONTINUE;
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}
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tail = MICHAEL_MIC_LEN;
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if (!info->control.hw_key)
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tail += TKIP_ICV_LEN;
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if (WARN_ON(skb_tailroom(skb) < tail ||
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skb_headroom(skb) < TKIP_IV_LEN))
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return TX_DROP;
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key = &tx->key->conf.key[NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY];
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mic = skb_put(skb, MICHAEL_MIC_LEN);
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michael_mic(key, hdr, data, data_len, mic);
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if (unlikely(info->flags & IEEE80211_TX_INTFL_TKIP_MIC_FAILURE))
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mic[0]++;
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return TX_CONTINUE;
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}
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ieee80211_rx_result
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ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
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{
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u8 *data, *key = NULL;
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size_t data_len;
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unsigned int hdrlen;
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u8 mic[MICHAEL_MIC_LEN];
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struct sk_buff *skb = rx->skb;
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struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
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struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
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/* No way to verify the MIC if the hardware stripped it */
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if (status->flag & RX_FLAG_MMIC_STRIPPED)
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return RX_CONTINUE;
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if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
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!ieee80211_has_protected(hdr->frame_control) ||
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!ieee80211_is_data_present(hdr->frame_control))
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return RX_CONTINUE;
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hdrlen = ieee80211_hdrlen(hdr->frame_control);
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if (skb->len < hdrlen + MICHAEL_MIC_LEN)
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return RX_DROP_UNUSABLE;
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data = skb->data + hdrlen;
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data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
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key = &rx->key->conf.key[NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY];
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michael_mic(key, hdr, data, data_len, mic);
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if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0) {
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if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
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return RX_DROP_UNUSABLE;
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mac80211_ev_michael_mic_failure(rx->sdata, rx->key->conf.keyidx,
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(void *) skb->data, NULL,
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GFP_ATOMIC);
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return RX_DROP_UNUSABLE;
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}
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/* remove Michael MIC from payload */
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skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
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/* update IV in key information to be able to detect replays */
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rx->key->u.tkip.rx[rx->queue].iv32 = rx->tkip_iv32;
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rx->key->u.tkip.rx[rx->queue].iv16 = rx->tkip_iv16;
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return RX_CONTINUE;
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}
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static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
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{
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struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
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struct ieee80211_key *key = tx->key;
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struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
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unsigned int hdrlen;
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int len, tail;
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u8 *pos;
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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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/* hwaccel - with no need for software-generated IV */
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return 0;
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}
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hdrlen = ieee80211_hdrlen(hdr->frame_control);
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len = skb->len - hdrlen;
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if (info->control.hw_key)
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tail = 0;
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else
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tail = TKIP_ICV_LEN;
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if (WARN_ON(skb_tailroom(skb) < tail ||
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skb_headroom(skb) < TKIP_IV_LEN))
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return -1;
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pos = skb_push(skb, TKIP_IV_LEN);
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memmove(pos, pos + TKIP_IV_LEN, hdrlen);
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pos += hdrlen;
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/* Increase IV for the frame */
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key->u.tkip.tx.iv16++;
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if (key->u.tkip.tx.iv16 == 0)
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key->u.tkip.tx.iv32++;
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pos = ieee80211_tkip_add_iv(pos, key, key->u.tkip.tx.iv16);
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/* hwaccel - with software IV */
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if (info->control.hw_key)
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return 0;
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/* Add room for ICV */
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skb_put(skb, TKIP_ICV_LEN);
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hdr = (struct ieee80211_hdr *) skb->data;
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return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
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key, pos, len, hdr->addr2);
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}
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ieee80211_tx_result
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ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
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{
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struct sk_buff *skb = tx->skb;
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ieee80211_tx_set_protected(tx);
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do {
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if (tkip_encrypt_skb(tx, skb) < 0)
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return TX_DROP;
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} while ((skb = skb->next));
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return TX_CONTINUE;
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}
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ieee80211_rx_result
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ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
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{
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struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
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int hdrlen, res, hwaccel = 0;
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struct ieee80211_key *key = rx->key;
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struct sk_buff *skb = rx->skb;
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struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
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hdrlen = ieee80211_hdrlen(hdr->frame_control);
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if (!ieee80211_is_data(hdr->frame_control))
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return RX_CONTINUE;
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if (!rx->sta || skb->len - hdrlen < 12)
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return RX_DROP_UNUSABLE;
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/*
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* Let TKIP code verify IV, but skip decryption.
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* In the case where hardware checks the IV as well,
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* we don't even get here, see ieee80211_rx_h_decrypt()
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*/
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if (status->flag & RX_FLAG_DECRYPTED)
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hwaccel = 1;
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res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
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key, skb->data + hdrlen,
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skb->len - hdrlen, rx->sta->sta.addr,
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hdr->addr1, hwaccel, rx->queue,
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&rx->tkip_iv32,
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&rx->tkip_iv16);
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if (res != TKIP_DECRYPT_OK)
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return RX_DROP_UNUSABLE;
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/* Trim ICV */
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skb_trim(skb, skb->len - TKIP_ICV_LEN);
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/* Remove IV */
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memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
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skb_pull(skb, TKIP_IV_LEN);
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return RX_CONTINUE;
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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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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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unsigned int hdrlen;
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struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
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b_0 = scratch + 3 * AES_BLOCK_LEN;
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aad = scratch + 4 * AES_BLOCK_LEN;
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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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*/
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mgmt = ieee80211_is_mgmt(hdr->frame_control);
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mask_fc = hdr->frame_control;
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mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
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IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
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if (!mgmt)
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mask_fc &= ~cpu_to_le16(0x0070);
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mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
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hdrlen = ieee80211_hdrlen(hdr->frame_control);
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len_a = hdrlen - 2;
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a4_included = ieee80211_has_a4(hdr->frame_control);
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if (ieee80211_is_data_qos(hdr->frame_control))
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qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
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else
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qos_tid = 0;
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data_len = skb->len - hdrlen - CCMP_HDR_LEN;
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if (encrypted)
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data_len -= CCMP_MIC_LEN;
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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, 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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put_unaligned_be16(len_a, &aad[0]);
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put_unaligned(mask_fc, (__le16 *)&aad[2]);
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memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
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/* Mask Seq#, leave Frag# */
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aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
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aad[23] = 0;
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if (a4_included) {
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memcpy(&aad[24], hdr->addr4, ETH_ALEN);
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aad[30] = qos_tid;
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aad[31] = 0;
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} else {
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memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
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aad[24] = qos_tid;
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}
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}
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static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
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{
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hdr[0] = pn[5];
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hdr[1] = pn[4];
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hdr[2] = 0;
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hdr[3] = 0x20 | (key_id << 6);
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hdr[4] = pn[3];
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hdr[5] = pn[2];
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hdr[6] = pn[1];
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hdr[7] = pn[0];
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}
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static inline void ccmp_hdr2pn(u8 *pn, u8 *hdr)
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{
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pn[0] = hdr[7];
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pn[1] = hdr[6];
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pn[2] = hdr[5];
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pn[3] = hdr[4];
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pn[4] = hdr[1];
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pn[5] = hdr[0];
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}
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static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
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{
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struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
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struct ieee80211_key *key = tx->key;
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struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
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int hdrlen, len, tail;
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u8 *pos, *pn;
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int i;
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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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/*
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* hwaccel has no need for preallocated room for CCMP
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* header or MIC fields
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*/
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return 0;
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}
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hdrlen = ieee80211_hdrlen(hdr->frame_control);
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len = skb->len - hdrlen;
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if (info->control.hw_key)
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tail = 0;
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else
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tail = CCMP_MIC_LEN;
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if (WARN_ON(skb_tailroom(skb) < tail ||
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skb_headroom(skb) < CCMP_HDR_LEN))
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return -1;
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pos = skb_push(skb, CCMP_HDR_LEN);
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memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
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hdr = (struct ieee80211_hdr *) pos;
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pos += hdrlen;
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/* PN = PN + 1 */
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pn = key->u.ccmp.tx_pn;
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for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
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pn[i]++;
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if (pn[i])
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break;
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}
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ccmp_pn2hdr(pos, pn, key->conf.keyidx);
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/* hwaccel - with software CCMP header */
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if (info->control.hw_key)
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return 0;
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pos += CCMP_HDR_LEN;
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ccmp_special_blocks(skb, pn, key->u.ccmp.tx_crypto_buf, 0);
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ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, key->u.ccmp.tx_crypto_buf, pos, len,
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pos, skb_put(skb, CCMP_MIC_LEN));
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return 0;
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}
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ieee80211_tx_result
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ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
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{
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struct sk_buff *skb = tx->skb;
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ieee80211_tx_set_protected(tx);
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do {
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if (ccmp_encrypt_skb(tx, skb) < 0)
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return TX_DROP;
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} while ((skb = skb->next));
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return TX_CONTINUE;
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}
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ieee80211_rx_result
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ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
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{
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struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
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int hdrlen;
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struct ieee80211_key *key = rx->key;
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struct sk_buff *skb = rx->skb;
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struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
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u8 pn[CCMP_PN_LEN];
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int data_len;
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int queue;
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hdrlen = ieee80211_hdrlen(hdr->frame_control);
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if (!ieee80211_is_data(hdr->frame_control) &&
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!ieee80211_is_robust_mgmt_frame(hdr))
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return RX_CONTINUE;
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data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
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if (!rx->sta || data_len < 0)
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return RX_DROP_UNUSABLE;
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ccmp_hdr2pn(pn, skb->data + hdrlen);
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queue = ieee80211_is_mgmt(hdr->frame_control) ?
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NUM_RX_DATA_QUEUES : rx->queue;
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if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) {
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key->u.ccmp.replays++;
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return RX_DROP_UNUSABLE;
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}
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if (!(status->flag & RX_FLAG_DECRYPTED)) {
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/* hardware didn't decrypt/verify MIC */
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ccmp_special_blocks(skb, pn, key->u.ccmp.rx_crypto_buf, 1);
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if (ieee80211_aes_ccm_decrypt(
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key->u.ccmp.tfm, key->u.ccmp.rx_crypto_buf,
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skb->data + hdrlen + CCMP_HDR_LEN, data_len,
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skb->data + skb->len - CCMP_MIC_LEN,
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skb->data + hdrlen + CCMP_HDR_LEN))
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return RX_DROP_UNUSABLE;
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}
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memcpy(key->u.ccmp.rx_pn[queue], pn, CCMP_PN_LEN);
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/* Remove CCMP header and MIC */
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skb_trim(skb, skb->len - CCMP_MIC_LEN);
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memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
|
|
skb_pull(skb, CCMP_HDR_LEN);
|
|
|
|
return RX_CONTINUE;
|
|
}
|
|
|
|
|
|
static void bip_aad(struct sk_buff *skb, u8 *aad)
|
|
{
|
|
/* BIP AAD: FC(masked) || A1 || A2 || A3 */
|
|
|
|
/* FC type/subtype */
|
|
aad[0] = skb->data[0];
|
|
/* Mask FC Retry, PwrMgt, MoreData flags to zero */
|
|
aad[1] = skb->data[1] & ~(BIT(4) | BIT(5) | BIT(6));
|
|
/* A1 || A2 || A3 */
|
|
memcpy(aad + 2, skb->data + 4, 3 * ETH_ALEN);
|
|
}
|
|
|
|
|
|
static inline void bip_ipn_swap(u8 *d, const u8 *s)
|
|
{
|
|
*d++ = s[5];
|
|
*d++ = s[4];
|
|
*d++ = s[3];
|
|
*d++ = s[2];
|
|
*d++ = s[1];
|
|
*d = s[0];
|
|
}
|
|
|
|
|
|
ieee80211_tx_result
|
|
ieee80211_crypto_aes_cmac_encrypt(struct ieee80211_tx_data *tx)
|
|
{
|
|
struct sk_buff *skb = tx->skb;
|
|
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
|
|
struct ieee80211_key *key = tx->key;
|
|
struct ieee80211_mmie *mmie;
|
|
u8 *pn, aad[20];
|
|
int i;
|
|
|
|
if (info->control.hw_key)
|
|
return 0;
|
|
|
|
if (WARN_ON(skb_tailroom(skb) < sizeof(*mmie)))
|
|
return TX_DROP;
|
|
|
|
mmie = (struct ieee80211_mmie *) skb_put(skb, sizeof(*mmie));
|
|
mmie->element_id = WLAN_EID_MMIE;
|
|
mmie->length = sizeof(*mmie) - 2;
|
|
mmie->key_id = cpu_to_le16(key->conf.keyidx);
|
|
|
|
/* PN = PN + 1 */
|
|
pn = key->u.aes_cmac.tx_pn;
|
|
|
|
for (i = sizeof(key->u.aes_cmac.tx_pn) - 1; i >= 0; i--) {
|
|
pn[i]++;
|
|
if (pn[i])
|
|
break;
|
|
}
|
|
bip_ipn_swap(mmie->sequence_number, pn);
|
|
|
|
bip_aad(skb, aad);
|
|
|
|
/*
|
|
* MIC = AES-128-CMAC(IGTK, AAD || Management Frame Body || MMIE, 64)
|
|
*/
|
|
ieee80211_aes_cmac(key->u.aes_cmac.tfm, key->u.aes_cmac.tx_crypto_buf,
|
|
aad, skb->data + 24, skb->len - 24, mmie->mic);
|
|
|
|
return TX_CONTINUE;
|
|
}
|
|
|
|
|
|
ieee80211_rx_result
|
|
ieee80211_crypto_aes_cmac_decrypt(struct ieee80211_rx_data *rx)
|
|
{
|
|
struct sk_buff *skb = rx->skb;
|
|
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
|
|
struct ieee80211_key *key = rx->key;
|
|
struct ieee80211_mmie *mmie;
|
|
u8 aad[20], mic[8], ipn[6];
|
|
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
|
|
|
|
if (!ieee80211_is_mgmt(hdr->frame_control))
|
|
return RX_CONTINUE;
|
|
|
|
if (skb->len < 24 + sizeof(*mmie))
|
|
return RX_DROP_UNUSABLE;
|
|
|
|
mmie = (struct ieee80211_mmie *)
|
|
(skb->data + skb->len - sizeof(*mmie));
|
|
if (mmie->element_id != WLAN_EID_MMIE ||
|
|
mmie->length != sizeof(*mmie) - 2)
|
|
return RX_DROP_UNUSABLE; /* Invalid MMIE */
|
|
|
|
bip_ipn_swap(ipn, mmie->sequence_number);
|
|
|
|
if (memcmp(ipn, key->u.aes_cmac.rx_pn, 6) <= 0) {
|
|
key->u.aes_cmac.replays++;
|
|
return RX_DROP_UNUSABLE;
|
|
}
|
|
|
|
if (!(status->flag & RX_FLAG_DECRYPTED)) {
|
|
/* hardware didn't decrypt/verify MIC */
|
|
bip_aad(skb, aad);
|
|
ieee80211_aes_cmac(key->u.aes_cmac.tfm,
|
|
key->u.aes_cmac.rx_crypto_buf, aad,
|
|
skb->data + 24, skb->len - 24, mic);
|
|
if (memcmp(mic, mmie->mic, sizeof(mmie->mic)) != 0) {
|
|
key->u.aes_cmac.icverrors++;
|
|
return RX_DROP_UNUSABLE;
|
|
}
|
|
}
|
|
|
|
memcpy(key->u.aes_cmac.rx_pn, ipn, 6);
|
|
|
|
/* Remove MMIE */
|
|
skb_trim(skb, skb->len - sizeof(*mmie));
|
|
|
|
return RX_CONTINUE;
|
|
}
|