mac80211: 802.11w - CCMP for management frames

Extend CCMP to support encryption and decryption of unicast management
frames.

Signed-off-by: Jouni Malinen <j@w1.fi>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 34 insertions, 7 deletions

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index cd6bc87eec73..50c6c4fabea5 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -330,6 +330,22 @@ ieee80211_tx_h_multicast_ps_buf(struct ieee80211_tx_data *tx)
         return TX_CONTINUE;
 }
 
+static int ieee80211_use_mfp(__le16 fc, struct sta_info *sta,
+                             struct sk_buff *skb)
+{
+        if (!ieee80211_is_mgmt(fc))
+                return 0;
+
+        if (sta == NULL || !test_sta_flags(sta, WLAN_STA_MFP))
+                return 0;
+
+        if (!ieee80211_is_robust_mgmt_frame((struct ieee80211_hdr *)
+                                            skb->data))
+                return 0;
+
+        return 1;
+}
+
 static ieee80211_tx_result
 ieee80211_tx_h_unicast_ps_buf(struct ieee80211_tx_data *tx)
 {
@@ -428,10 +444,15 @@ ieee80211_tx_h_select_key(struct ieee80211_tx_data *tx)
                         if (ieee80211_is_auth(hdr->frame_control))
                                 break;
                 case ALG_TKIP:
-                case ALG_CCMP:
                         if (!ieee80211_is_data_present(hdr->frame_control))
                                 tx->key = NULL;
                         break;
+                case ALG_CCMP:
+                        if (!ieee80211_is_data_present(hdr->frame_control) &&
+                            !ieee80211_use_mfp(hdr->frame_control, tx->sta,
+                                               tx->skb))
+                                tx->key = NULL;
+                        break;
                 }
         }
 
diff --git a/net/mac80211/wpa.c b/net/mac80211/wpa.c
index 7aa63caf8d50..aff46adde3f0 100644
--- a/net/mac80211/wpa.c
+++ b/net/mac80211/wpa.c
@@ -266,7 +266,7 @@ static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
                                 int encrypted)
 {
         __le16 mask_fc;
-        int a4_included;
+        int a4_included, mgmt;
         u8 qos_tid;
         u8 *b_0, *aad;
         u16 data_len, len_a;
@@ -277,12 +277,15 @@ static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
         aad = scratch + 4 * AES_BLOCK_LEN;
 
         /*
-         * Mask FC: zero subtype b4 b5 b6
+         * Mask FC: zero subtype b4 b5 b6 (if not mgmt)
          * Retry, PwrMgt, MoreData; set Protected
          */
+        mgmt = ieee80211_is_mgmt(hdr->frame_control);
         mask_fc = hdr->frame_control;
-        mask_fc &= ~cpu_to_le16(0x0070 | IEEE80211_FCTL_RETRY |
+        mask_fc &= ~cpu_to_le16(IEEE80211_FCTL_RETRY |
                                 IEEE80211_FCTL_PM | IEEE80211_FCTL_MOREDATA);
+        if (!mgmt)
+                mask_fc &= ~cpu_to_le16(0x0070);
         mask_fc |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 
         hdrlen = ieee80211_hdrlen(hdr->frame_control);
@@ -300,8 +303,10 @@ static void ccmp_special_blocks(struct sk_buff *skb, u8 *pn, u8 *scratch,
 
         /* First block, b_0 */
         b_0[0] = 0x59; /* flags: Adata: 1, M: 011, L: 001 */
-        /* Nonce: QoS Priority | A2 | PN */
-        b_0[1] = qos_tid;
+        /* Nonce: Nonce Flags | A2 | PN
+         * Nonce Flags: Priority (b0..b3) | Management (b4) | Reserved (b5..b7)
+         */
+        b_0[1] = qos_tid | (mgmt << 4);
         memcpy(&b_0[2], hdr->addr2, ETH_ALEN);
         memcpy(&b_0[8], pn, CCMP_PN_LEN);
         /* l(m) */
@@ -446,7 +451,8 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx)
 
         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 
-        if (!ieee80211_is_data(hdr->frame_control))
+        if (!ieee80211_is_data(hdr->frame_control) &&
+            !ieee80211_is_robust_mgmt_frame(hdr))
                 return RX_CONTINUE;
 
         data_len = skb->len - hdrlen - CCMP_HDR_LEN - CCMP_MIC_LEN;