[PATCH] mac80211: fix TKIP IV update

The TKIP IV should be updated only after MMIC verification,
this patch changes it to be at that spot.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

4 files changed, 21 insertions, 8 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 636de70cd85d..32d19bbf522c 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -153,6 +153,8 @@ struct ieee80211_txrx_data {
                         int sent_ps_buffered;
                         int queue;
                         int load;
+                        u32 tkip_iv32;
+                        u16 tkip_iv16;
                 } rx;
         } u;
 };
diff --git a/net/mac80211/tkip.c b/net/mac80211/tkip.c
index 5b11f14abfba..3abe194e4d55 100644
--- a/net/mac80211/tkip.c
+++ b/net/mac80211/tkip.c
@@ -238,7 +238,8 @@ void ieee80211_tkip_encrypt_data(struct crypto_blkcipher *tfm,
 int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm,
                                 struct ieee80211_key *key,
                                 u8 *payload, size_t payload_len, u8 *ta,
-                                int only_iv, int queue)
+                                int only_iv, int queue,
+                                u32 *out_iv32, u16 *out_iv16)
 {
         u32 iv32;
         u32 iv16;
@@ -332,11 +333,14 @@ int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm,
         res = ieee80211_wep_decrypt_data(tfm, rc4key, 16, pos, payload_len - 12);
  done:
         if (res == TKIP_DECRYPT_OK) {
-                /* FIX: these should be updated only after Michael MIC has been
-                 * verified */
-                /* Record previously received IV */
-                key->u.tkip.iv32_rx[queue] = iv32;
-                key->u.tkip.iv16_rx[queue] = iv16;
+                /*
+                 * Record previously received IV, will be copied into the
+                 * key information after MIC verification. It is possible
+                 * that we don't catch replays of fragments but that's ok
+                 * because the Michael MIC verication will then fail.
+                 */
+                *out_iv32 = iv32;
+                *out_iv16 = iv16;
         }
 
         return res;
diff --git a/net/mac80211/tkip.h b/net/mac80211/tkip.h
index a0d181a18049..73d8ef2a93b0 100644
--- a/net/mac80211/tkip.h
+++ b/net/mac80211/tkip.h
@@ -31,6 +31,7 @@ enum {
 int ieee80211_tkip_decrypt_data(struct crypto_blkcipher *tfm,
                                 struct ieee80211_key *key,
                                 u8 *payload, size_t payload_len, u8 *ta,
-                                int only_iv, int queue);
+                                int only_iv, int queue,
+                                u32 *out_iv32, u16 *out_iv16);
 
 #endif /* TKIP_H */
diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index a07fd7484cdf..6695efba57ec 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -175,6 +175,10 @@ ieee80211_rx_h_michael_mic_verify(struct ieee80211_txrx_data *rx)
         /* 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;
 }
 
@@ -315,7 +319,9 @@ ieee80211_crypto_tkip_decrypt(struct ieee80211_txrx_data *rx)
         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);
+                                          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",