mac80211: simplify RX PN/IV handling

The current rx->queue value is slightly confusing.
It is set to 16 on non-QoS frames, including data,
and then used for sequence number and PN/IV checks.
Until recently, we had a TKIP IV checking bug that
had been introduced in 2008 to fix a seqno issue.
Before that, we always used TID 0 for checking the
PN or IV on non-QoS packets.

Go back to the old status for PN/IV checks using
the TID 0 counter for non-QoS by splitting up the
rx->queue value into "seqno_idx" and "security_idx"
in order to avoid confusion in the future. They
each have special rules on the value used for non-
QoS data frames.

Since the handling is now unified, also revert the
special TKIP handling from my patch
"mac80211: fix TKIP replay vulnerability".

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

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 4f2e424..4c7a831 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -202,7 +202,22 @@ struct ieee80211_rx_data {
        struct ieee80211_key *key;
 
        unsigned int flags;
-       int queue;
+
+       /*
+        * Index into sequence numbers array, 0..16
+        * since the last (16) is used for non-QoS,
+        * will be 16 on non-QoS frames.
+        */
+       int seqno_idx;
+
+       /*
+        * Index into the security IV/PN arrays, 0..16
+        * since the last (16) is used for CCMP-encrypted
+        * management frames, will be set to 16 on mgmt
+        * frames and 0 on non-QoS frames.
+        */
+       int security_idx;
+
        u32 tkip_iv32;
        u16 tkip_iv16;
 };

diff --git a/net/mac80211/key.h b/net/mac80211/key.h
index 05abab0..beb9c20 100644 (file)
--- a/net/mac80211/key.h
+++ b/net/mac80211/key.h
@@ -29,7 +29,7 @@
 #define TKIP_IV_LEN            8
 #define TKIP_ICV_LEN           4
 
-#define NUM_RX_DATA_QUEUES     17
+#define NUM_RX_DATA_QUEUES     16
 
 struct ieee80211_local;
 struct ieee80211_sub_if_data;

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index b5493ec..e6dccc7 100644 (file)
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -331,7 +331,7 @@ static void ieee80211_parse_qos(struct ieee80211_rx_data *rx)
 {
        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)rx->skb->data;
        struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
-       int tid;
+       int tid, seqno_idx, security_idx;
 
        /* does the frame have a qos control field? */
        if (ieee80211_is_data_qos(hdr->frame_control)) {
@@ -340,6 +340,9 @@ static void ieee80211_parse_qos(struct ieee80211_rx_data *rx)
                tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
                if (*qc & IEEE80211_QOS_CTL_A_MSDU_PRESENT)
                        status->rx_flags |= IEEE80211_RX_AMSDU;
+
+               seqno_idx = tid;
+               security_idx = tid;
        } else {
                /*
                 * IEEE 802.11-2007, 7.1.3.4.1 ("Sequence Number field"):
@@ -352,10 +355,15 @@ static void ieee80211_parse_qos(struct ieee80211_rx_data *rx)
                 *
                 * We also use that counter for non-QoS STAs.
                 */
-               tid = NUM_RX_DATA_QUEUES - 1;
+               seqno_idx = NUM_RX_DATA_QUEUES;
+               security_idx = 0;
+               if (ieee80211_is_mgmt(hdr->frame_control))
+                       security_idx = NUM_RX_DATA_QUEUES;
+               tid = 0;
        }
 
-       rx->queue = tid;
+       rx->seqno_idx = seqno_idx;
+       rx->security_idx = security_idx;
        /* Set skb->priority to 1d tag if highest order bit of TID is not set.
         * For now, set skb->priority to 0 for other cases. */
        rx->skb->priority = (tid > 7) ? 0 : tid;
@@ -810,7 +818,7 @@ ieee80211_rx_h_check(struct ieee80211_rx_data *rx)
        /* Drop duplicate 802.11 retransmissions (IEEE 802.11 Chap. 9.2.9) */
        if (rx->sta && !is_multicast_ether_addr(hdr->addr1)) {
                if (unlikely(ieee80211_has_retry(hdr->frame_control) &&
-                            rx->sta->last_seq_ctrl[rx->queue] ==
+                            rx->sta->last_seq_ctrl[rx->seqno_idx] ==
                             hdr->seq_ctrl)) {
                        if (status->rx_flags & IEEE80211_RX_RA_MATCH) {
                                rx->local->dot11FrameDuplicateCount++;
@@ -818,7 +826,7 @@ ieee80211_rx_h_check(struct ieee80211_rx_data *rx)
                        }
                        return RX_DROP_UNUSABLE;
                } else
-                       rx->sta->last_seq_ctrl[rx->queue] = hdr->seq_ctrl;
+                       rx->sta->last_seq_ctrl[rx->seqno_idx] = hdr->seq_ctrl;
        }
 
        if (unlikely(rx->skb->len < 16)) {
@@ -1374,11 +1382,10 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
        if (frag == 0) {
                /* This is the first fragment of a new frame. */
                entry = ieee80211_reassemble_add(rx->sdata, frag, seq,
-                                                rx->queue, &(rx->skb));
+                                                rx->seqno_idx, &(rx->skb));
                if (rx->key && rx->key->conf.cipher == WLAN_CIPHER_SUITE_CCMP &&
                    ieee80211_has_protected(fc)) {
-                       int queue = ieee80211_is_mgmt(fc) ?
-                               NUM_RX_DATA_QUEUES : rx->queue;
+                       int queue = rx->security_idx;
                        /* Store CCMP PN so that we can verify that the next
                         * fragment has a sequential PN value. */
                        entry->ccmp = 1;
@@ -1392,7 +1399,8 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
        /* This is a fragment for a frame that should already be pending in
         * fragment cache. Add this fragment to the end of the pending entry.
         */
-       entry = ieee80211_reassemble_find(rx->sdata, frag, seq, rx->queue, hdr);
+       entry = ieee80211_reassemble_find(rx->sdata, frag, seq,
+                                         rx->seqno_idx, hdr);
        if (!entry) {
                I802_DEBUG_INC(rx->local->rx_handlers_drop_defrag);
                return RX_DROP_MONITOR;
@@ -1412,8 +1420,7 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
                        if (pn[i])
                                break;
                }
-               queue = ieee80211_is_mgmt(fc) ?
-                       NUM_RX_DATA_QUEUES : rx->queue;
+               queue = rx->security_idx;
                rpn = rx->key->u.ccmp.rx_pn[queue];
                if (memcmp(pn, rpn, CCMP_PN_LEN))
                        return RX_DROP_UNUSABLE;
@@ -2590,7 +2597,9 @@ void ieee80211_release_reorder_timeout(struct sta_info *sta, int tid)
                .sta = sta,
                .sdata = sta->sdata,
                .local = sta->local,
-               .queue = tid,
+               /* This is OK -- must be QoS data frame */
+               .security_idx = tid,
+               .seqno_idx = tid,
                .flags = 0,
        };
        struct tid_ampdu_rx *tid_agg_rx;

diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index a06d64e..28beb78 100644 (file)
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -287,7 +287,8 @@ struct sta_info {
        unsigned long rx_dropped;
        int last_signal;
        struct ewma avg_signal;
-       __le16 last_seq_ctrl[NUM_RX_DATA_QUEUES];
+       /* Plus 1 for non-QoS frames */
+       __le16 last_seq_ctrl[NUM_RX_DATA_QUEUES + 1];
 
        /* Updated from TX status path only, no locking requirements */
        unsigned long tx_filtered_count;

diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index 0168423..7bc8702 100644 (file)
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -149,8 +149,8 @@ ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
 
 update_iv:
        /* 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[rx->security_idx].iv32 = rx->tkip_iv32;
+       rx->key->u.tkip.rx[rx->security_idx].iv16 = rx->tkip_iv16;
 
        return RX_CONTINUE;
 
@@ -263,7 +263,7 @@ ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
        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, rx->security_idx,
                                          &rx->tkip_iv32,
                                          &rx->tkip_iv16);
        if (res != TKIP_DECRYPT_OK)
@@ -478,8 +478,7 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
 
        ccmp_hdr2pn(pn, skb->data + hdrlen);
 
-       queue = ieee80211_is_mgmt(hdr->frame_control) ?
-               NUM_RX_DATA_QUEUES : rx->queue;
+       queue = rx->security_idx;
 
        if (memcmp(pn, key->u.ccmp.rx_pn[queue], CCMP_PN_LEN) <= 0) {
                key->u.ccmp.replays++;