wpa.c
/*
* Copyright 2002-2004, Instant802 Networks, 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.
*/
#include <linux/netdevice.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/compiler.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "michael.h"
#include "tkip.h"
#include "aes_ccm.h"
#include "wpa.h"
static int ieee80211_get_hdr_info(const struct sk_buff *skb, u8 **sa, u8 **da,
u8 *qos_tid, u8 **data, size_t *data_len)
{
struct ieee80211_hdr *hdr;
size_t hdrlen;
u16 fc;
int a4_included;
u8 *pos;
hdr = (struct ieee80211_hdr *) skb->data;
fc = le16_to_cpu(hdr->frame_control);
hdrlen = 24;
if ((fc & (IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) ==
(IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS)) {
hdrlen += ETH_ALEN;
*sa = hdr->addr4;
*da = hdr->addr3;
} else if (fc & IEEE80211_FCTL_FROMDS) {
*sa = hdr->addr3;
*da = hdr->addr1;
} else if (fc & IEEE80211_FCTL_TODS) {
*sa = hdr->addr2;
*da = hdr->addr3;
} else {
*sa = hdr->addr2;
*da = hdr->addr1;
}
if (fc & 0x80)
hdrlen += 2;
*data = skb->data + hdrlen;
*data_len = skb->len - hdrlen;
a4_included = (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS);
if ((fc & IEEE80211_FCTL_FTYPE) == IEEE80211_FTYPE_DATA &&
fc & IEEE80211_STYPE_QOS_DATA) {
pos = (u8 *) &hdr->addr4;
if (a4_included)
pos += 6;
*qos_tid = pos[0] & 0x0f;
*qos_tid |= 0x80; /* qos_included flag */
} else
*qos_tid = 0;
return skb->len < hdrlen ? -1 : 0;
}
ieee80211_txrx_result
ieee80211_tx_h_michael_mic_add(struct ieee80211_txrx_data *tx)
{
u8 *data, *sa, *da, *key, *mic, qos_tid;
size_t data_len;
u16 fc;
struct sk_buff *skb = tx->skb;
int authenticator;
int wpa_test = 0;
fc = tx->fc;
if (!tx->key || tx->key->conf.alg != ALG_TKIP || skb->len < 24 ||
!WLAN_FC_DATA_PRESENT(fc))
return TXRX_CONTINUE;
if (ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len))
return TXRX_DROP;
if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
!(tx->flags & IEEE80211_TXRXD_FRAGMENTED) &&
!(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) &&
!wpa_test) {
/* hwaccel - with no need for preallocated room for Michael MIC
*/
return TXRX_CONTINUE;
}
if (skb_tailroom(skb) < MICHAEL_MIC_LEN) {
I802_DEBUG_INC(tx->local->tx_expand_skb_head);
if (unlikely(pskb_expand_head(skb, TKIP_IV_LEN,
MICHAEL_MIC_LEN + TKIP_ICV_LEN,
GFP_ATOMIC))) {
printk(KERN_DEBUG "%s: failed to allocate more memory "
"for Michael MIC\n", tx->dev->name);
return TXRX_DROP;
}
}
#if 0
authenticator = fc & IEEE80211_FCTL_FROMDS; /* FIX */
#else
authenticator = 1;
#endif
key = &tx->key->conf.key[authenticator ? ALG_TKIP_TEMP_AUTH_TX_MIC_KEY :
ALG_TKIP_TEMP_AUTH_RX_MIC_KEY];
mic = skb_put(skb, MICHAEL_MIC_LEN);
michael_mic(key, da, sa, qos_tid & 0x0f, data, data_len, mic);
return TXRX_CONTINUE;
}
ieee80211_txrx_result
ieee80211_rx_h_michael_mic_verify(struct ieee80211_txrx_data *rx)
{
u8 *data, *sa, *da, *key = NULL, qos_tid;
size_t data_len;
u16 fc;
u8 mic[MICHAEL_MIC_LEN];
struct sk_buff *skb = rx->skb;
int authenticator = 1, wpa_test = 0;
DECLARE_MAC_BUF(mac);
fc = rx->fc;
/*
* No way to verify the MIC if the hardware stripped it
*/
if (rx->u.rx.status->flag & RX_FLAG_MMIC_STRIPPED)
return TXRX_CONTINUE;
if (!rx->key || rx->key->conf.alg != ALG_TKIP ||
!(rx->fc & IEEE80211_FCTL_PROTECTED) || !WLAN_FC_DATA_PRESENT(fc))
return TXRX_CONTINUE;
if (ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len)
|| data_len < MICHAEL_MIC_LEN)
return TXRX_DROP;
data_len -= MICHAEL_MIC_LEN;
#if 0
authenticator = fc & IEEE80211_FCTL_TODS; /* FIX */
#else
authenticator = 1;
#endif
key = &rx->key->conf.key[authenticator ? ALG_TKIP_TEMP_AUTH_RX_MIC_KEY :
ALG_TKIP_TEMP_AUTH_TX_MIC_KEY];
michael_mic(key, da, sa, qos_tid & 0x0f, data, data_len, mic);
if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0 || wpa_test) {
if (!(rx->flags & IEEE80211_TXRXD_RXRA_MATCH))
return TXRX_DROP;
printk(KERN_DEBUG "%s: invalid Michael MIC in data frame from "
"%s\n", rx->dev->name, print_mac(mac, sa));
mac80211_ev_michael_mic_failure(rx->dev, rx->key->conf.keyidx,
(void *) skb->data);
return TXRX_DROP;
}
/* remove Michael MIC from payload */
skb_trim(skb, skb->len - MICHAEL_MIC_LEN);
/* update IV in key information to be able to detect replays */
rx->key->u.tkip.iv32_rx[rx->u.rx.queue] = rx->u.rx.tkip_iv32;
rx->key->u.tkip.iv16_rx[rx->u.rx.queue] = rx->u.rx.tkip_iv16;
return TXRX_CONTINUE;
}
static int tkip_encrypt_skb(struct ieee80211_txrx_data *tx,
struct sk_buff *skb, int test)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
struct ieee80211_key *key = tx->key;
int hdrlen, len, tailneed;
u16 fc;
u8 *pos;
fc = le16_to_cpu(hdr->frame_control);
hdrlen = ieee80211_get_hdrlen(fc);
len = skb->len - hdrlen;
if (tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
tailneed = 0;
else
tailneed = TKIP_ICV_LEN;
if ((skb_headroom(skb) < TKIP_IV_LEN ||
skb_tailroom(skb) < tailneed)) {
I802_DEBUG_INC(tx->local->tx_expand_skb_head);
if (unlikely(pskb_expand_head(skb, TKIP_IV_LEN, tailneed,
GFP_ATOMIC)))
return -1;
}
pos = skb_push(skb, TKIP_IV_LEN);
memmove(pos, pos + TKIP_IV_LEN, hdrlen);
pos += hdrlen;
/* Increase IV for the frame */
key->u.tkip.iv16++;
if (key->u.tkip.iv16 == 0)
key->u.tkip.iv32++;
if (tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
hdr = (struct ieee80211_hdr *)skb->data;
/* hwaccel - with preallocated room for IV */
ieee80211_tkip_add_iv(pos, key,
(u8) (key->u.tkip.iv16 >> 8),
(u8) (((key->u.tkip.iv16 >> 8) | 0x20) &
0x7f),
(u8) key->u.tkip.iv16);
tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
return 0;
}
/* Add room for ICV */
skb_put(skb, TKIP_ICV_LEN);
hdr = (struct ieee80211_hdr *) skb->data;
ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
key, pos, len, hdr->addr2);
return 0;
}
ieee80211_txrx_result
ieee80211_crypto_tkip_encrypt(struct ieee80211_txrx_data *tx)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
u16 fc;
struct sk_buff *skb = tx->skb;
int wpa_test = 0, test = 0;
fc = le16_to_cpu(hdr->frame_control);
if (!WLAN_FC_DATA_PRESENT(fc))
return TXRX_CONTINUE;
tx->u.tx.control->icv_len = TKIP_ICV_LEN;
tx->u.tx.control->iv_len = TKIP_IV_LEN;
ieee80211_tx_set_iswep(tx);
if ((tx->key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
!(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) &&
!wpa_test) {
/* hwaccel - with no need for preallocated room for IV/ICV */
tx->u.tx.control->key_idx = tx->key->conf.hw_key_idx;
return TXRX_CONTINUE;
}
if (tkip_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 (tkip_encrypt_skb(tx, tx->u.tx.extra_frag[i], test)
< 0)
return TXRX_DROP;
}
}
return TXRX_CONTINUE;
}
ieee80211_txrx_result
ieee80211_crypto_tkip_decrypt(struct ieee80211_txrx_data *rx)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
u16 fc;
int hdrlen, res, hwaccel = 0, wpa_test = 0;
struct ieee80211_key *key = rx->key;
struct sk_buff *skb = rx->skb;
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;
if (!rx->sta || skb->len - hdrlen < 12)
return TXRX_DROP;
if (rx->u.rx.status->flag & RX_FLAG_DECRYPTED) {
if (rx->u.rx.status->flag & RX_FLAG_IV_STRIPPED) {
/*
* Hardware took care of all processing, including
* replay protection, and stripped the ICV/IV so
* we cannot do any checks here.
*/
return TXRX_CONTINUE;
}
/* let TKIP code verify IV, but skip decryption */
hwaccel = 1;
}
res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
key, skb->data + hdrlen,
skb->len - hdrlen, rx->sta->addr,
hwaccel, rx->u.rx.queue,
&rx->u.rx.tkip_iv32,
&rx->u.rx.tkip_iv16);
if (res != TKIP_DECRYPT_OK || wpa_test) {
printk(KERN_DEBUG "%s: TKIP decrypt failed for RX frame from "
"%s (res=%d)\n",
rx->dev->name, print_mac(mac, rx->sta->addr), res);
return TXRX_DROP;
}
/* Trim ICV */
skb_trim(skb, skb->len - TKIP_ICV_LEN);
/* Remove IV */
memmove(skb->data + TKIP_IV_LEN, skb->data, hdrlen);
skb_pull(skb, TKIP_IV_LEN);
return TXRX_CONTINUE;
}
static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *b_0, u8 *aad,
int encrypted)
{
u16 fc;
int a4_included, qos_included;
u8 qos_tid, *fc_pos, *data, *sa, *da;
int len_a;
size_t data_len;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
fc_pos = (u8 *) &hdr->frame_control;
fc = fc_pos[0] ^ (fc_pos[1] << 8);
a4_included = (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS);
ieee80211_get_hdr_info(skb, &sa, &da, &qos_tid, &data, &data_len);
data_len -= CCMP_HDR_LEN + (encrypted ? CCMP_MIC_LEN : 0);
if (qos_tid & 0x80) {
qos_included = 1;
qos_tid &= 0x0f;
} else
qos_included = 0;
/* First block, b_0 */
b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
/* Nonce: QoS Priority | A2 | PN */
b_0[1] = qos_tid;
memcpy(&b_0[2], hdr->addr2, 6);
memcpy(&b_0[8], pn, CCMP_PN_LEN);
/* l(m) */
b_0[14] = (data_len >> 8) & 0xff;
b_0[15] = data_len & 0xff;
/* AAD (extra authenticate-only data) / masked 802.11 header
* FC | A1 | A2 | A3 | SC | [A4] | [QC] */
len_a = a4_included ? 28 : 22;
if (qos_included)
len_a += 2;
aad[0] = 0; /* (len_a >> 8) & 0xff; */
aad[1] = len_a & 0xff;
/* Mask FC: zero subtype b4 b5 b6 */
aad[2] = fc_pos[0] & ~(BIT(4) | BIT(5) | BIT(6));
/* Retry, PwrMgt, MoreData; set Protected */
aad[3] = (fc_pos[1] & ~(BIT(3) | BIT(4) | BIT(5))) | BIT(6);
memcpy(&aad[4], &hdr->addr1, 18);
/* Mask Seq#, leave Frag# */
aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
aad[23] = 0;
if (a4_included) {
memcpy(&aad[24], hdr->addr4, 6);
aad[30] = 0;
aad[31] = 0;
} else
memset(&aad[24], 0, 8);
if (qos_included) {
u8 *dpos = &aad[a4_included ? 30 : 24];
/* Mask QoS Control field */
dpos[0] = qos_tid;
dpos[1] = 0;
}
}
static inline void ccmp_pn2hdr(u8 *hdr, u8 *pn, int key_id)
{
hdr[0] = pn[5];
hdr[1] = pn[4];
hdr[2] = 0;
hdr[3] = 0x20 | (key_id << 6);
hdr[4] = pn[3];
hdr[5] = pn[2];
hdr[6] = pn[1];
hdr[7] = pn[0];
}
static inline int ccmp_hdr2pn(u8 *pn, u8 *hdr)
{
pn[0] = hdr[7];
pn[1] = hdr[6];
pn[2] = hdr[5];
pn[3] = hdr[4];
pn[4] = hdr[1];
pn[5] = hdr[0];
return (hdr[3] >> 6) & 0x03;
}
static int ccmp_encrypt_skb(struct ieee80211_txrx_data *tx,
struct sk_buff *skb, int test)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
struct ieee80211_key *key = tx->key;
int hdrlen, len, tailneed;
u16 fc;
u8 *pos, *pn, *b_0, *aad, *scratch;
int i;
scratch = key->u.ccmp.tx_crypto_buf;
b_0 = scratch + 3 * AES_BLOCK_LEN;
aad = scratch + 4 * AES_BLOCK_LEN;
fc = le16_to_cpu(hdr->frame_control);
hdrlen = ieee80211_get_hdrlen(fc);
len = skb->len - hdrlen;
if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)
tailneed = 0;
else
tailneed = CCMP_MIC_LEN;
if ((skb_headroom(skb) < CCMP_HDR_LEN ||
skb_tailroom(skb) < tailneed)) {
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 ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
u16 fc;
struct sk_buff *skb = tx->skb;
int test = 0;
fc = le16_to_cpu(hdr->frame_control);
if (!WLAN_FC_DATA_PRESENT(fc))
return TXRX_CONTINUE;
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)) {
printk(KERN_DEBUG "%s: CCMP decrypt failed for RX "
"frame from %s\n", rx->dev->name,
print_mac(mac, rx->sta->addr));
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;
}