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mac80211: fix CCMP races

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Since we can process multiple packets at the
same time for different ACs, but the PN is
allocated from a single counter, we need to
use an atomic value there. Use atomic64_t to
make this cheaper on 64-bit platforms, other
platforms will support this through software
emulation, see lib/atomic64.c.

We also need to use an on-stack scratch buf
so that multiple packets won't corrupt each
others scratch buffers.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Johannes Berg
2011-07-06 21:59:39 +02:00
committed by John W. Linville
parent 523b02ea23
commit aba83a0b30
4 changed files with 32 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files

32
net/mac80211/wpa.c
View File

@@ -15,6 +15,7 @@
#include <linux/gfp.h>
#include <asm/unaligned.h>
#include <net/mac80211.h>
#include <crypto/aes.h>
#include "ieee80211_i.h"
#include "michael.h"
@@ -290,6 +291,8 @@ static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
unsigned int hdrlen;
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
memset(scratch, 0, 6 * AES_BLOCK_LEN);
b_0 = scratch + 3 * AES_BLOCK_LEN;
aad = scratch + 4 * AES_BLOCK_LEN;
@@ -380,8 +383,10 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
struct ieee80211_key *key = tx->key;
struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
int hdrlen, len, tail;
u8 *pos, *pn;
int i;
u8 *pos;
u8 pn[6];
u64 pn64;
u8 scratch[6 * AES_BLOCK_LEN];
if (info->control.hw_key &&
!(info->control.hw_key->flags & IEEE80211_KEY_FLAG_GENERATE_IV)) {
@@ -409,14 +414,14 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
hdr = (struct ieee80211_hdr *) pos;
pos += hdrlen;
/* PN = PN + 1 */
pn = key->u.ccmp.tx_pn;
pn64 = atomic64_inc_return(&key->u.ccmp.tx_pn);
for (i = CCMP_PN_LEN - 1; i >= 0; i--) {
pn[i]++;
if (pn[i])
break;
}
pn[5] = pn64;
pn[4] = pn64 >> 8;
pn[3] = pn64 >> 16;
pn[2] = pn64 >> 24;
pn[1] = pn64 >> 32;
pn[0] = pn64 >> 40;
ccmp_pn2hdr(pos, pn, key->conf.keyidx);
@@ -425,8 +430,8 @@ static int ccmp_encrypt_skb(struct ieee80211_tx_data *tx, struct sk_buff *skb)
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,
ccmp_special_blocks(skb, pn, scratch, 0);
ieee80211_aes_ccm_encrypt(key->u.ccmp.tfm, scratch, pos, len,
pos, skb_put(skb, CCMP_MIC_LEN));
return 0;
@@ -482,11 +487,12 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
}
if (!(status->flag & RX_FLAG_DECRYPTED)) {
u8 scratch[6 * AES_BLOCK_LEN];
/* hardware didn't decrypt/verify MIC */
ccmp_special_blocks(skb, pn, key->u.ccmp.rx_crypto_buf, 1);
ccmp_special_blocks(skb, pn, scratch, 1);
if (ieee80211_aes_ccm_decrypt(
key->u.ccmp.tfm, key->u.ccmp.rx_crypto_buf,
key->u.ccmp.tfm, scratch,
skb->data + hdrlen + CCMP_HDR_LEN, data_len,
skb->data + skb->len - CCMP_MIC_LEN,
skb->data + hdrlen + CCMP_HDR_LEN))