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Commit aba83a0b authored by Johannes Berg's avatar Johannes Berg Committed by John W. Linville
Browse files

mac80211: fix CCMP races 



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: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 523b02ea

net/mac80211/cfg.c

+8 −6
Original line number Diff line number Diff line
@@ -209,6 +209,7 @@ static int ieee80211_get_key(struct wiphy *wiphy, struct net_device *dev, 
	u8 seq[6] = {0};

	struct key_params params;

	struct ieee80211_key *key = NULL;

	u64 pn64;

	u32 iv32;

	u16 iv16;

	int err = -ENOENT;
@@ -256,12 +257,13 @@ static int ieee80211_get_key(struct wiphy *wiphy, struct net_device *dev, 
		params.seq_len = 6;

		break;

	case WLAN_CIPHER_SUITE_CCMP:

		seq[0] = key->u.ccmp.tx_pn[5];

		seq[1] = key->u.ccmp.tx_pn[4];

		seq[2] = key->u.ccmp.tx_pn[3];

		seq[3] = key->u.ccmp.tx_pn[2];

		seq[4] = key->u.ccmp.tx_pn[1];

		seq[5] = key->u.ccmp.tx_pn[0];

		pn64 = atomic64_read(&key->u.ccmp.tx_pn);

		seq[0] = pn64;

		seq[1] = pn64 >> 8;

		seq[2] = pn64 >> 16;

		seq[3] = pn64 >> 24;

		seq[4] = pn64 >> 32;

		seq[5] = pn64 >> 40;

		params.seq = seq;

		params.seq_len = 6;

		break;

net/mac80211/debugfs_key.c

+4 −2
Original line number Diff line number Diff line
@@ -79,6 +79,7 @@ static ssize_t key_tx_spec_read(struct file *file, char __user *userbuf, 
				size_t count, loff_t *ppos)

{

	const u8 *tpn;

	u64 pn;

	char buf[20];

	int len;

	struct ieee80211_key *key = file->private_data;
@@ -94,9 +95,10 @@ static ssize_t key_tx_spec_read(struct file *file, char __user *userbuf, 
				key->u.tkip.tx.iv16);

		break;

	case WLAN_CIPHER_SUITE_CCMP:

		tpn = key->u.ccmp.tx_pn;

		pn = atomic64_read(&key->u.ccmp.tx_pn);

		len = scnprintf(buf, sizeof(buf), "%02x%02x%02x%02x%02x%02x\n",

				tpn[0], tpn[1], tpn[2], tpn[3], tpn[4], tpn[5]);

				(u8)(pn >> 40), (u8)(pn >> 32), (u8)(pn >> 24),

				(u8)(pn >> 16), (u8)(pn >> 8), (u8)pn);

		break;

	case WLAN_CIPHER_SUITE_AES_CMAC:

		tpn = key->u.aes_cmac.tx_pn;

net/mac80211/key.h

+1 −4
Original line number Diff line number Diff line
@@ -82,7 +82,7 @@ struct ieee80211_key { 
			struct tkip_ctx rx[NUM_RX_DATA_QUEUES];

		} tkip;

		struct {

			u8 tx_pn[6];

			atomic64_t tx_pn;

			/*

			 * Last received packet number. The first

			 * NUM_RX_DATA_QUEUES counters are used with Data
@@ -92,12 +92,9 @@ struct ieee80211_key { 
			u8 rx_pn[NUM_RX_DATA_QUEUES + 1][6];

			struct crypto_cipher *tfm;

			u32 replays; /* dot11RSNAStatsCCMPReplays */

			/* scratch buffers for virt_to_page() (crypto API) */

#ifndef AES_BLOCK_LEN

#define AES_BLOCK_LEN 16

#endif

			u8 tx_crypto_buf[6 * AES_BLOCK_LEN];

			u8 rx_crypto_buf[6 * AES_BLOCK_LEN];

		} ccmp;

		struct {

			u8 tx_pn[6];

net/mac80211/wpa.c

+19 −13
Original line number Diff line number Diff line
@@ -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))