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linux/net/mac80211/wpa.c
Johannes Berg 554891e63a mac80211: move packet flags into packet 
commit 8c0c709eea
Author: Johannes Berg <johannes@sipsolutions.net>
Date:   Wed Nov 25 17:46:15 2009 +0100

    mac80211: move cmntr flag out of rx flags

moved the CMNTR flag into the skb RX flags for
some aggregation cleanups, but this was wrong
since the optimisation this flag tried to make
requires that it is kept across the processing
of multiple interfaces -- which isn't true for
flags in the skb. The patch not only broke the
optimisation, it also introduced a bug: under
some (common!) circumstances the flag will be
set on an already freed skb!

However, investigating this in more detail, I
found that most of the flags that we set should
be per packet, _except_ for this one, due to
a-MPDU processing. Additionally, the flags used
for processing (currently just this one) need
to be reset before processing a new packet.

Since we haven't actually seen bugs reported as
a result of the wrong flags handling (which is
not too surprising -- the only real bug case I
can come up with is an a-MSDU contained in an
a-MPDU), I'll make a different fix for rc.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2010-09-27 15:57:54 -04:00

592 lines
14 KiB
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/*
* Copyright 2002-2004, Instant802 Networks, Inc.
* Copyright 2008, Jouni Malinen <j@w1.fi>
*
* 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/skbuff.h>
#include <linux/compiler.h>
#include <linux/ieee80211.h>
#include <linux/gfp.h>
#include <asm/unaligned.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "michael.h"
#include "tkip.h"
#include "aes_ccm.h"
#include "aes_cmac.h"
#include "wpa.h"
ieee80211_tx_result
ieee80211_tx_h_michael_mic_add(struct ieee80211_tx_data *tx)
{
u8 *data, *key, *mic, key_offset;
size_t data_len;
unsigned int hdrlen;
struct ieee80211_hdr *hdr;
struct sk_buff *skb = tx->skb;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
int authenticator;
int tail;
hdr = (struct ieee80211_hdr *)skb->data;
if (!tx->key || tx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
skb->len < 24 || !ieee80211_is_data_present(hdr->frame_control))
return TX_CONTINUE;
hdrlen = ieee80211_hdrlen(hdr->frame_control);
if (skb->len < hdrlen)
return TX_DROP;
data = skb->data + hdrlen;
data_len = skb->len - hdrlen;
if (info->control.hw_key &&
!(tx->flags & IEEE80211_TX_FRAGMENTED) &&
!(tx->key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC)) {
/* hwaccel - with no need for SW-generated MMIC */
return TX_CONTINUE;
}
tail = MICHAEL_MIC_LEN;
if (!info->control.hw_key)
tail += TKIP_ICV_LEN;
if (WARN_ON(skb_tailroom(skb) < tail ||
skb_headroom(skb) < TKIP_IV_LEN))
return TX_DROP;
#if 0
authenticator = fc & IEEE80211_FCTL_FROMDS; /* FIX */
#else
authenticator = 1;
#endif
key_offset = authenticator ?
NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY :
NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY;
key = &tx->key->conf.key[key_offset];
mic = skb_put(skb, MICHAEL_MIC_LEN);
michael_mic(key, hdr, data, data_len, mic);
return TX_CONTINUE;
}
ieee80211_rx_result
ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
{
u8 *data, *key = NULL, key_offset;
size_t data_len;
unsigned int hdrlen;
u8 mic[MICHAEL_MIC_LEN];
struct sk_buff *skb = rx->skb;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
int authenticator = 1, wpa_test = 0;
/* No way to verify the MIC if the hardware stripped it */
if (status->flag & RX_FLAG_MMIC_STRIPPED)
return RX_CONTINUE;
if (!rx->key || rx->key->conf.cipher != WLAN_CIPHER_SUITE_TKIP ||
!ieee80211_has_protected(hdr->frame_control) ||
!ieee80211_is_data_present(hdr->frame_control))
return RX_CONTINUE;
hdrlen = ieee80211_hdrlen(hdr->frame_control);
if (skb->len < hdrlen + MICHAEL_MIC_LEN)
return RX_DROP_UNUSABLE;
data = skb->data + hdrlen;
data_len = skb->len - hdrlen - MICHAEL_MIC_LEN;
#if 0
authenticator = fc & IEEE80211_FCTL_TODS; /* FIX */
#else
authenticator = 1;
#endif
key_offset = authenticator ?
NL80211_TKIP_DATA_OFFSET_RX_MIC_KEY :
NL80211_TKIP_DATA_OFFSET_TX_MIC_KEY;
key = &rx->key->conf.key[key_offset];
michael_mic(key, hdr, data, data_len, mic);
if (memcmp(mic, data + data_len, MICHAEL_MIC_LEN) != 0 || wpa_test) {
if (!(status->rx_flags & IEEE80211_RX_RA_MATCH))
return RX_DROP_UNUSABLE;
mac80211_ev_michael_mic_failure(rx->sdata, rx->key->conf.keyidx,
(void *) skb->data, NULL,
GFP_ATOMIC);
return RX_DROP_UNUSABLE;
}
/* 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.rx[rx->queue].iv32 = rx->tkip_iv32;
rx->key->u.tkip.rx[rx->queue].iv16 = rx->tkip_iv16;
return RX_CONTINUE;
}
static int tkip_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
struct ieee80211_key *key = tx->key;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
unsigned int hdrlen;
int len, tail;
u8 *pos;
if (info->control.hw_key &&
!(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
/* hwaccel - with no need for software-generated IV */
return 0;
}
hdrlen = ieee80211_hdrlen(hdr->frame_control);
len = skb->len - hdrlen;
if (info->control.hw_key)
tail = 0;
else
tail = TKIP_ICV_LEN;
if (WARN_ON(skb_tailroom(skb) < tail ||
skb_headroom(skb) < TKIP_IV_LEN))
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.tx.iv16++;
if (key->u.tkip.tx.iv16 == 0)
key->u.tkip.tx.iv32++;
pos = ieee80211_tkip_add_iv(pos, key, key->u.tkip.tx.iv16);
/* hwaccel - with software IV */
if (info->control.hw_key)
return 0;
/* Add room for ICV */
skb_put(skb, TKIP_ICV_LEN);
hdr = (struct ieee80211_hdr *) skb->data;
return ieee80211_tkip_encrypt_data(tx->local->wep_tx_tfm,
key, pos, len, hdr->addr2);
}
ieee80211_tx_result
ieee80211_crypto_tkip_encrypt(struct ieee80211_tx_data *tx)
{
struct sk_buff *skb = tx->skb;
ieee80211_tx_set_protected(tx);
do {
if (tkip_encrypt_skb(tx, skb) < 0)
return TX_DROP;
} while ((skb = skb->next));
return TX_CONTINUE;
}
ieee80211_rx_result
ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) rx->skb->data;
int hdrlen, res, hwaccel = 0, wpa_test = 0;
struct ieee80211_key *key = rx->key;
struct sk_buff *skb = rx->skb;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
hdrlen = ieee80211_hdrlen(hdr->frame_control);
if (!ieee80211_is_data(hdr->frame_control))
return RX_CONTINUE;
if (!rx->sta || skb->len - hdrlen < 12)
return RX_DROP_UNUSABLE;
/*
* Let TKIP code verify IV, but skip decryption.
* In the case where hardware checks the IV as well,
* we don't even get here, see ieee80211_rx_h_decrypt()
*/
if (status->flag & RX_FLAG_DECRYPTED)
hwaccel = 1;
res = ieee80211_tkip_decrypt_data(rx->local->wep_rx_tfm,
key, skb->data + hdrlen,
skb->len - hdrlen, rx->sta->sta.addr,
hdr->addr1, hwaccel, rx->queue,
&rx->tkip_iv32,
&rx->tkip_iv16);
if (res != TKIP_DECRYPT_OK || wpa_test)
return RX_DROP_UNUSABLE;
/* 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 RX_CONTINUE;
}
static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
int encrypted)
{
__le16 mask_fc;
int a4_included, mgmt;
u8 qos_tid;
u8 *b_0, *aad;
u16 data_len, len_a;
unsigned int hdrlen;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
b_0 = scratch + 3 * AES_BLOCK_LEN;
aad = scratch + 4 * AES_BLOCK_LEN;
/*
* Mask FC: zero subtype b4 b5 b6 (if not mgmt)
* Retry, PwrMgt, MoreData; set Protected
*/
mgmt = ieee80211_is_mgmt(hdr->frame_control);
mask_fc = hdr->frame_control;
mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
if (!mgmt)
mask_fc &= ~cpu_to_le16(0x0070);
mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
hdrlen = ieee80211_hdrlen(hdr->frame_control);
len_a = hdrlen - 2;
a4_included = ieee80211_has_a4(hdr->frame_control);
if (ieee80211_is_data_qos(hdr->frame_control))
qos_tid = *ieee80211_get_qos_ctl(hdr) & IEEE80211_QOS_CTL_TID_MASK;
else
qos_tid = 0;
data_len = skb->len - hdrlen - CCMP_HDR_LEN;
if (encrypted)
data_len -= CCMP_MIC_LEN;
/* First block, b_0 */
b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
/* Nonce: Nonce Flags | A2 | PN
* Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
*/
b_0[1] = qos_tid | (mgmt << 4);
memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
memcpy(&b_0[8], pn, CCMP_PN_LEN);
/* l(m) */
put_unaligned_be16(data_len, &b_0[14]);
/* AAD (extra authenticate-only data) / masked 802.11 header
* FC | A1 | A2 | A3 | SC | [A4] | [QC] */
put_unaligned_be16(len_a, &aad[0]);
put_unaligned(mask_fc, (__le16 *)&aad[2]);
memcpy(&aad[4], &hdr->addr1, 3 * ETH_ALEN);
/* Mask Seq#, leave Frag# */
aad[22] = *((u8 *) &hdr->seq_ctrl) & 0x0f;
aad[23] = 0;
if (a4_included) {
memcpy(&aad[24], hdr->addr4, ETH_ALEN);
aad[30] = qos_tid;
aad[31] = 0;
} else {
memset(&aad[24], 0, ETH_ALEN + IEEE80211_QOS_CTL_LEN);
aad[24] = qos_tid;
}
}
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 void 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];
}
static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
struct ieee80211_key *key = tx->key;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
int hdrlen, len, tail;
u8 *pos, *pn;
int i;
if (info->control.hw_key &&
!(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
/*
* hwaccel has no need for preallocated room for CCMP
* header or MIC fields
*/
return 0;
}
hdrlen = ieee80211_hdrlen(hdr->frame_control);
len = skb->len - hdrlen;
if (info->control.hw_key)
tail = 0;
else
tail = CCMP_MIC_LEN;
if (WARN_ON(skb_tailroom(skb) < tail ||
skb_headroom(skb) < CCMP_HDR_LEN))
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);
/* hwaccel - with software CCMP header */
if (info->control.hw_key)
return 0;
pos += CCMP_HDR_LEN;
ccmp_special_blocks(skb, pn, key->u.ccmp.tx_crypto_buf, 0);
ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, key->u.ccmp.tx_crypto_buf, pos, len,
pos, skb_put(skb, CCMP_MIC_LEN));
return 0;
}
ieee80211_tx_result
ieee80211_crypto_ccmp_encrypt(struct ieee80211_tx_data *tx)
{
struct sk_buff *skb = tx->skb;
ieee80211_tx_set_protected(tx);
do {
if (ccmp_encrypt_skb(tx, skb) < 0)
return TX_DROP;
} while ((skb = skb->next));
return TX_CONTINUE;
}
ieee80211_rx_result
ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
int hdrlen;
struct ieee80211_key *key = rx->key;
struct sk_buff *skb = rx->skb;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
u8 pn[CCMP_PN_LEN];
int data_len;
int queue;
hdrlen = ieee80211_hdrlen(hdr->frame_control);
if (!ieee80211_is_data(hdr->frame_control) &&
!ieee80211_is_robust_mgmt_frame(hdr))
return RX_CONTINUE;
data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;
if (!rx->sta || data_len < 0)
return RX_DROP_UNUSABLE;
ccmp_hdr2pn(pn, skb->data + hdrlen);
queue = ieee80211_is_mgmt(hdr->frame_control) ?
NUM_RX_DATA_QUEUES : rx->queue;
if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) {
key->u.ccmp.replays++;
return RX_DROP_UNUSABLE;
}
if (!(status->flag & RX_FLAG_DECRYPTED)) {
/* hardware didn't decrypt/verify MIC */
ccmp_special_blocks(skb, pn, key->u.ccmp.rx_crypto_buf, 1);
if (ieee80211_aes_ccm_decrypt(
key->u.ccmp.tfm, key->u.ccmp.rx_crypto_buf,
skb->data + hdrlen + CCMP_HDR_LEN, data_len,
skb->data + skb->len - CCMP_MIC_LEN,
skb->data + hdrlen + CCMP_HDR_LEN))
return RX_DROP_UNUSABLE;
}
memcpy(key->u.ccmp.rx_pn[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 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;
}
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