This is a note to let you know that I've just added the patch titled
mac80211: fix TKIP replay vulnerability
to the 2.6.39-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mac80211-fix-tkip-replay-vulnerability.patch
and it can be found in the queue-2.6.39 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 34459512ffa7236c849466e3bd604801389734e1 Mon Sep 17 00:00:00 2001
From: Johannes Berg <[email protected]>
Date: Thu, 7 Jul 2011 18:24:54 +0200
Subject: mac80211: fix TKIP replay vulnerability
From: Johannes Berg <[email protected]>
commit 34459512ffa7236c849466e3bd604801389734e1 upstream.
Unlike CCMP, the presence or absence of the QoS
field doesn't change the encryption, only the
TID is used. When no QoS field is present, zero
is used as the TID value. This means that it is
possible for an attacker to take a QoS packet
with TID 0 and replay it as a non-QoS packet.
Unfortunately, mac80211 uses different IVs for
checking the validity of the packet's TKIP IV
when it checks TID 0 and when it checks non-QoS
packets. This means it is vulnerable to this
replay attack.
To fix this, use the same replay counter for
TID 0 and non-QoS packets by overriding the
rx->queue value to 0 if it is 16 (non-QoS).
This is a minimal fix for now. I caused this
issue in
commit 1411f9b531f0a910cd1c85a337737c1e6ffbae6a
Author: Johannes Berg <[email protected]>
Date: Thu Jul 10 10:11:02 2008 +0200
mac80211: fix RX sequence number check
while fixing a sequence number issue (there,
a separate counter needs to be used).
Signed-off-by: Johannes Berg <[email protected]>
Signed-off-by: John W. Linville <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
net/mac80211/wpa.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -86,6 +86,11 @@ ieee80211_rx_h_michael_mic_verify(struct
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 queue = rx->queue;
+
+ /* otherwise, TKIP is vulnerable to TID 0 vs. non-QoS replays */
+ if (rx->queue == NUM_RX_DATA_QUEUES - 1)
+ queue = 0;
/* No way to verify the MIC if the hardware stripped it */
if (status->flag & RX_FLAG_MMIC_STRIPPED)
@@ -119,8 +124,8 @@ ieee80211_rx_h_michael_mic_verify(struct
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;
+ rx->key->u.tkip.rx[queue].iv32 = rx->tkip_iv32;
+ rx->key->u.tkip.rx[queue].iv16 = rx->tkip_iv16;
return RX_CONTINUE;
}
@@ -201,6 +206,11 @@ ieee80211_crypto_tkip_decrypt(struct iee
struct ieee80211_key *key = rx->key;
struct sk_buff *skb = rx->skb;
struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
+ int queue = rx->queue;
+
+ /* otherwise, TKIP is vulnerable to TID 0 vs. non-QoS replays */
+ if (rx->queue == NUM_RX_DATA_QUEUES - 1)
+ queue = 0;
hdrlen = ieee80211_hdrlen(hdr->frame_control);
@@ -221,7 +231,7 @@ ieee80211_crypto_tkip_decrypt(struct iee
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,
+ hdr->addr1, hwaccel, queue,
&rx->tkip_iv32,
&rx->tkip_iv16);
if (res != TKIP_DECRYPT_OK)
Patches currently in stable-queue which might be from [email protected]
are
queue-2.6.39/mac80211-fix-tkip-replay-vulnerability.patch
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