![Johannes Berg](/assets/img/avatar_default.png)
This patch moves the decision making about whether a frame is encrypted with a certain algorithm up into the TX handlers rather than having it in the crypto algorithm implementation. This fixes a problem with the radiotap injection code where injecting a non-data packet and requesting encryption could end up asking the driver to encrypt a packet without giving it a key. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
605 lines
15 KiB
C
605 lines
15 KiB
C
/*
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* Copyright 2002-2004, Instant802 Networks, 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 <linux/netdevice.h>
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/skbuff.h>
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#include <linux/compiler.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 "wpa.h"
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static int ieee80211_get_hdr_info(const struct sk_buff *skb, u8 **sa, u8 **da,
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u8 *qos_tid, u8 **data, size_t *data_len)
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{
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struct ieee80211_hdr *hdr;
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size_t hdrlen;
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u16 fc;
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int a4_included;
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u8 *pos;
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hdr = (struct ieee80211_hdr *) skb->data;
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fc = le16_to_cpu(hdr->frame_control);
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hdrlen = 24;
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if ((fc & (IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) ==
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(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) {
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hdrlen += ETH_ALEN;
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*sa = hdr->addr4;
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*da = hdr->addr3;
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} else if (fc & IEEE80211_FCTL_FROMDS) {
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*sa = hdr->addr3;
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*da = hdr->addr1;
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} else if (fc & IEEE80211_FCTL_TODS) {
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*sa = hdr->addr2;
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*da = hdr->addr3;
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} else {
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*sa = hdr->addr2;
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*da = hdr->addr1;
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}
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if (fc & 0x80)
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hdrlen += 2;
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*data = skb->data + hdrlen;
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*data_len = skb->len - hdrlen;
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a4_included = (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
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(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS);
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if ((fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_DATA &&
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fc & IEEE80211_STYPE_QOS_DATA) {
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pos = (u8 *) &hdr->addr4;
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if (a4_included)
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pos += 6;
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*qos_tid = pos[0] & 0x0f;
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*qos_tid |= 0x80; /* qos_included flag */
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} else
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*qos_tid = 0;
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return skb->len < hdrlen ? -1 : 0;
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}
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ieee80211_txrx_result
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ieee80211_tx_h_michael_mic_add(struct ieee80211_txrx_data *tx)
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{
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u8 *data, *sa, *da, *key, *mic, qos_tid;
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size_t data_len;
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u16 fc;
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struct sk_buff *skb = tx->skb;
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int authenticator;
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int wpa_test = 0;
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fc = tx->fc;
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if (!tx->key || tx->key->conf.alg != ALG_TKIP || skb->len < 24 ||
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!WLAN_FC_DATA_PRESENT(fc))
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return TXRX_CONTINUE;
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if (ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len))
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return TXRX_DROP;
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if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
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!(tx->flags & IEEE80211_TXRXD_FRAGMENTED) &&
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!(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) &&
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!wpa_test) {
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/* hwaccel - with no need for preallocated room for Michael MIC
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*/
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return TXRX_CONTINUE;
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}
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if (skb_tailroom(skb) < MICHAEL_MIC_LEN) {
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I802_DEBUG_INC(tx->local->tx_expand_skb_head);
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if (unlikely(pskb_expand_head(skb, TKIP_IV_LEN,
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MICHAEL_MIC_LEN + TKIP_ICV_LEN,
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GFP_ATOMIC))) {
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printk(KERN_DEBUG "%s: failed to allocate more memory "
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"for Michael MIC\n", tx->dev->name);
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return TXRX_DROP;
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}
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}
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#if 0
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authenticator = fc & IEEE80211_FCTL_FROMDS; /* FIX */
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#else
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authenticator = 1;
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#endif
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key = &tx->key->conf.key[authenticator ? ALG_TKIP_TEMP_AUTH_TX_MIC_KEY :
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ALG_TKIP_TEMP_AUTH_RX_MIC_KEY];
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mic = skb_put(skb, MICHAEL_MIC_LEN);
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michael_mic(key, da, sa, qos_tid & 0x0f, data, data_len, mic);
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return TXRX_CONTINUE;
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}
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ieee80211_txrx_result
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ieee80211_rx_h_michael_mic_verify(struct ieee80211_txrx_data *rx)
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{
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u8 *data, *sa, *da, *key = NULL, qos_tid;
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size_t data_len;
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u16 fc;
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u8 mic[MICHAEL_MIC_LEN];
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struct sk_buff *skb = rx->skb;
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int authenticator = 1, wpa_test = 0;
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DECLARE_MAC_BUF(mac);
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fc = rx->fc;
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/*
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* No way to verify the MIC if the hardware stripped it
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*/
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if (rx->u.rx.status->flag & RX_FLAG_MMIC_STRIPPED)
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return TXRX_CONTINUE;
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if (!rx->key || rx->key->conf.alg != ALG_TKIP ||
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!(rx->fc & IEEE80211_FCTL_PROTECTED) || !WLAN_FC_DATA_PRESENT(fc))
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return TXRX_CONTINUE;
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if (ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len)
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|| data_len < MICHAEL_MIC_LEN)
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return TXRX_DROP;
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data_len -= MICHAEL_MIC_LEN;
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#if 0
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authenticator = fc & IEEE80211_FCTL_TODS; /* FIX */
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#else
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authenticator = 1;
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#endif
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key = &rx->key->conf.key[authenticator ? ALG_TKIP_TEMP_AUTH_RX_MIC_KEY :
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ALG_TKIP_TEMP_AUTH_TX_MIC_KEY];
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michael_mic(key, da, sa, qos_tid & 0x0f, data, data_len, mic);
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if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0 || wpa_test) {
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if (!(rx->flags & IEEE80211_TXRXD_RXRA_MATCH))
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return TXRX_DROP;
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printk(KERN_DEBUG "%s: invalid Michael MIC in data frame from "
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"%s\n", rx->dev->name, print_mac(mac, sa));
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mac80211_ev_michael_mic_failure(rx->dev, rx->key->conf.keyidx,
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(void *) skb->data);
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return TXRX_DROP;
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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.iv32_rx[rx->u.rx.queue] = rx->u.rx.tkip_iv32;
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rx->key->u.tkip.iv16_rx[rx->u.rx.queue] = rx->u.rx.tkip_iv16;
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return TXRX_CONTINUE;
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}
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static int tkip_encrypt_skb(struct ieee80211_txrx_data *tx,
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struct sk_buff *skb, int test)
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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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int hdrlen, len, tailneed;
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u16 fc;
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u8 *pos;
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fc = le16_to_cpu(hdr->frame_control);
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hdrlen = ieee80211_get_hdrlen(fc);
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len = skb->len - hdrlen;
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if (tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
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tailneed = 0;
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else
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tailneed = TKIP_ICV_LEN;
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if ((skb_headroom(skb) < TKIP_IV_LEN ||
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skb_tailroom(skb) < tailneed)) {
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I802_DEBUG_INC(tx->local->tx_expand_skb_head);
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if (unlikely(pskb_expand_head(skb, TKIP_IV_LEN, tailneed,
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GFP_ATOMIC)))
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return -1;
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}
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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.iv16++;
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if (key->u.tkip.iv16 == 0)
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key->u.tkip.iv32++;
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if (tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
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hdr = (struct ieee80211_hdr *)skb->data;
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/* hwaccel - with preallocated room for IV */
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ieee80211_tkip_add_iv(pos, key,
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(u8) (key->u.tkip.iv16 >> 8),
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(u8) (((key->u.tkip.iv16 >> 8) | 0x20) &
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0x7f),
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(u8) key->u.tkip.iv16);
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tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
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return 0;
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}
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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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ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
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key, pos, len, hdr->addr2);
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return 0;
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}
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ieee80211_txrx_result
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ieee80211_crypto_tkip_encrypt(struct ieee80211_txrx_data *tx)
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{
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struct sk_buff *skb = tx->skb;
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int wpa_test = 0, test = 0;
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tx->u.tx.control->icv_len = TKIP_ICV_LEN;
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tx->u.tx.control->iv_len = TKIP_IV_LEN;
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ieee80211_tx_set_iswep(tx);
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if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
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!(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
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!wpa_test) {
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/* hwaccel - with no need for preallocated room for IV/ICV */
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tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
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return TXRX_CONTINUE;
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}
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if (tkip_encrypt_skb(tx, skb, test) < 0)
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return TXRX_DROP;
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if (tx->u.tx.extra_frag) {
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int i;
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for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
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if (tkip_encrypt_skb(tx, tx->u.tx.extra_frag[i], test)
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< 0)
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return TXRX_DROP;
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}
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}
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return TXRX_CONTINUE;
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}
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ieee80211_txrx_result
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ieee80211_crypto_tkip_decrypt(struct ieee80211_txrx_data *rx)
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{
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struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
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u16 fc;
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int hdrlen, res, hwaccel = 0, wpa_test = 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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DECLARE_MAC_BUF(mac);
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fc = le16_to_cpu(hdr->frame_control);
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hdrlen = ieee80211_get_hdrlen(fc);
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if ((rx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA)
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return TXRX_CONTINUE;
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if (!rx->sta || skb->len - hdrlen < 12)
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return TXRX_DROP;
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if (rx->u.rx.status->flag & RX_FLAG_DECRYPTED) {
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if (rx->u.rx.status->flag & RX_FLAG_IV_STRIPPED) {
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/*
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* Hardware took care of all processing, including
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* replay protection, and stripped the ICV/IV so
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* we cannot do any checks here.
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*/
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return TXRX_CONTINUE;
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}
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/* let TKIP code verify IV, but skip decryption */
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hwaccel = 1;
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}
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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->addr,
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hwaccel, rx->u.rx.queue,
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&rx->u.rx.tkip_iv32,
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&rx->u.rx.tkip_iv16);
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if (res != TKIP_DECRYPT_OK || wpa_test) {
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#ifdef CONFIG_MAC80211_DEBUG
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if (net_ratelimit())
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printk(KERN_DEBUG "%s: TKIP decrypt failed for RX "
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"frame from %s (res=%d)\n", rx->dev->name,
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print_mac(mac, rx->sta->addr), res);
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#endif /* CONFIG_MAC80211_DEBUG */
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return TXRX_DROP;
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}
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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 TXRX_CONTINUE;
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}
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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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u16 fc;
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int a4_included, qos_included;
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u8 qos_tid, *fc_pos, *data, *sa, *da;
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int len_a;
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size_t data_len;
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struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
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fc_pos = (u8 *) &hdr->frame_control;
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fc = fc_pos[0] ^ (fc_pos[1] << 8);
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a4_included = (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
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(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS);
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ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len);
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data_len -= CCMP_HDR_LEN + (encrypted ? CCMP_MIC_LEN : 0);
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if (qos_tid & 0x80) {
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qos_included = 1;
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qos_tid &= 0x0f;
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} else
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qos_included = 0;
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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: QoS Priority | A2 | PN */
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b_0[1] = qos_tid;
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memcpy(&b_0[2], hdr->addr2, 6);
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memcpy(&b_0[8], pn, CCMP_PN_LEN);
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/* l(m) */
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b_0[14] = (data_len >> 8) & 0xff;
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b_0[15] = data_len & 0xff;
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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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len_a = a4_included ? 28 : 22;
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if (qos_included)
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len_a += 2;
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aad[0] = 0; /* (len_a >> 8) & 0xff; */
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aad[1] = len_a & 0xff;
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/* Mask FC: zero subtype b4 b5 b6 */
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aad[2] = fc_pos[0] & ~(BIT(4) | BIT(5) | BIT(6));
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/* Retry, PwrMgt, MoreData; set Protected */
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aad[3] = (fc_pos[1] & ~(BIT(3) | BIT(4) | BIT(5))) | BIT(6);
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memcpy(&aad[4], &hdr->addr1, 18);
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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, 6);
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aad[30] = 0;
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aad[31] = 0;
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} else
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memset(&aad[24], 0, 8);
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if (qos_included) {
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u8 *dpos = &aad[a4_included ? 30 : 24];
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/* Mask QoS Control field */
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dpos[0] = qos_tid;
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dpos[1] = 0;
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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 int 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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return (hdr[3] >> 6) & 0x03;
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}
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static int ccmp_encrypt_skb(struct ieee80211_txrx_data *tx,
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struct sk_buff *skb, int test)
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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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int hdrlen, len, tailneed;
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u16 fc;
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u8 *pos, *pn, *b_0, *aad, *scratch;
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int i;
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scratch = key->u.ccmp.tx_crypto_buf;
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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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fc = le16_to_cpu(hdr->frame_control);
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hdrlen = ieee80211_get_hdrlen(fc);
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len = skb->len - hdrlen;
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if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
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tailneed = 0;
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else
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tailneed = CCMP_MIC_LEN;
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if ((skb_headroom(skb) < CCMP_HDR_LEN ||
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skb_tailroom(skb) < tailneed)) {
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I802_DEBUG_INC(tx->local->tx_expand_skb_head);
|
|
if (unlikely(pskb_expand_head(skb, CCMP_HDR_LEN, tailneed,
|
|
GFP_ATOMIC)))
|
|
return -1;
|
|
}
|
|
|
|
pos = skb_push(skb, CCMP_HDR_LEN);
|
|
memmove(pos, pos + CCMP_HDR_LEN, hdrlen);
|
|
hdr = (struct ieee80211_hdr *) pos;
|
|
pos += hdrlen;
|
|
|
|
/* PN = PN + 1 */
|
|
pn = key->u.ccmp.tx_pn;
|
|
|
|
for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
|
|
pn[i]++;
|
|
if (pn[i])
|
|
break;
|
|
}
|
|
|
|
ccmp_pn2hdr(pos, pn, key->conf.keyidx);
|
|
|
|
if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
|
|
/* hwaccel - with preallocated room for CCMP header */
|
|
tx->u.tx.control->key_idx = key->conf.hw_key_idx;
|
|
return 0;
|
|
}
|
|
|
|
pos += CCMP_HDR_LEN;
|
|
ccmp_special_blocks(skb, pn, b_0, aad, 0);
|
|
ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, b_0, aad, pos, len,
|
|
pos, skb_put(skb, CCMP_MIC_LEN));
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
ieee80211_txrx_result
|
|
ieee80211_crypto_ccmp_encrypt(struct ieee80211_txrx_data *tx)
|
|
{
|
|
struct sk_buff *skb = tx->skb;
|
|
int test = 0;
|
|
|
|
tx->u.tx.control->icv_len = CCMP_MIC_LEN;
|
|
tx->u.tx.control->iv_len = CCMP_HDR_LEN;
|
|
ieee80211_tx_set_iswep(tx);
|
|
|
|
if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
|
|
!(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
|
|
/* hwaccel - with no need for preallocated room for CCMP "
|
|
* header or MIC fields */
|
|
tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
|
|
return TXRX_CONTINUE;
|
|
}
|
|
|
|
if (ccmp_encrypt_skb(tx, skb, test) < 0)
|
|
return TXRX_DROP;
|
|
|
|
if (tx->u.tx.extra_frag) {
|
|
int i;
|
|
for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
|
|
if (ccmp_encrypt_skb(tx, tx->u.tx.extra_frag[i], test)
|
|
< 0)
|
|
return TXRX_DROP;
|
|
}
|
|
}
|
|
|
|
return TXRX_CONTINUE;
|
|
}
|
|
|
|
|
|
ieee80211_txrx_result
|
|
ieee80211_crypto_ccmp_decrypt(struct ieee80211_txrx_data *rx)
|
|
{
|
|
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
|
|
u16 fc;
|
|
int hdrlen;
|
|
struct ieee80211_key *key = rx->key;
|
|
struct sk_buff *skb = rx->skb;
|
|
u8 pn[CCMP_PN_LEN];
|
|
int data_len;
|
|
DECLARE_MAC_BUF(mac);
|
|
|
|
fc = le16_to_cpu(hdr->frame_control);
|
|
hdrlen = ieee80211_get_hdrlen(fc);
|
|
|
|
if ((rx->fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA)
|
|
return TXRX_CONTINUE;
|
|
|
|
data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
|
|
if (!rx->sta || data_len < 0)
|
|
return TXRX_DROP;
|
|
|
|
if ((rx->u.rx.status->flag & RX_FLAG_DECRYPTED) &&
|
|
(rx->u.rx.status->flag & RX_FLAG_IV_STRIPPED))
|
|
return TXRX_CONTINUE;
|
|
|
|
(void) ccmp_hdr2pn(pn, skb->data + hdrlen);
|
|
|
|
if (memcmp(pn, key->u.ccmp.rx_pn[rx->u.rx.queue], CCMP_PN_LEN) <= 0) {
|
|
#ifdef CONFIG_MAC80211_DEBUG
|
|
u8 *ppn = key->u.ccmp.rx_pn[rx->u.rx.queue];
|
|
|
|
printk(KERN_DEBUG "%s: CCMP replay detected for RX frame from "
|
|
"%s (RX PN %02x%02x%02x%02x%02x%02x <= prev. PN "
|
|
"%02x%02x%02x%02x%02x%02x)\n", rx->dev->name,
|
|
print_mac(mac, rx->sta->addr),
|
|
pn[0], pn[1], pn[2], pn[3], pn[4], pn[5],
|
|
ppn[0], ppn[1], ppn[2], ppn[3], ppn[4], ppn[5]);
|
|
#endif /* CONFIG_MAC80211_DEBUG */
|
|
key->u.ccmp.replays++;
|
|
return TXRX_DROP;
|
|
}
|
|
|
|
if (!(rx->u.rx.status->flag & RX_FLAG_DECRYPTED)) {
|
|
/* hardware didn't decrypt/verify MIC */
|
|
u8 *scratch, *b_0, *aad;
|
|
|
|
scratch = key->u.ccmp.rx_crypto_buf;
|
|
b_0 = scratch + 3 * AES_BLOCK_LEN;
|
|
aad = scratch + 4 * AES_BLOCK_LEN;
|
|
|
|
ccmp_special_blocks(skb, pn, b_0, aad, 1);
|
|
|
|
if (ieee80211_aes_ccm_decrypt(
|
|
key->u.ccmp.tfm, scratch, b_0, aad,
|
|
skb->data + hdrlen + CCMP_HDR_LEN, data_len,
|
|
skb->data + skb->len - CCMP_MIC_LEN,
|
|
skb->data + hdrlen + CCMP_HDR_LEN)) {
|
|
#ifdef CONFIG_MAC80211_DEBUG
|
|
if (net_ratelimit())
|
|
printk(KERN_DEBUG "%s: CCMP decrypt failed "
|
|
"for RX frame from %s\n", rx->dev->name,
|
|
print_mac(mac, rx->sta->addr));
|
|
#endif /* CONFIG_MAC80211_DEBUG */
|
|
return TXRX_DROP;
|
|
}
|
|
}
|
|
|
|
memcpy(key->u.ccmp.rx_pn[rx->u.rx.queue], pn, CCMP_PN_LEN);
|
|
|
|
/* Remove CCMP header and MIC */
|
|
skb_trim(skb, skb->len - CCMP_MIC_LEN);
|
|
memmove(skb->data + CCMP_HDR_LEN, skb->data, hdrlen);
|
|
skb_pull(skb, CCMP_HDR_LEN);
|
|
|
|
return TXRX_CONTINUE;
|
|
}
|