cfg80211/mac80211: allow per-station GTKs

This adds API to allow adding per-station GTKs,
updates mac80211 to support it, and also allows
drivers to remove a key from hwaccel again when
this may be necessary due to multiple GTKs.

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

8 files changed, 123 insertions, 68 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 94bf550..8b0e874 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -103,7 +103,7 @@ static int ieee80211_change_iface(struct wiphy *wiphy,
 }
 
 static int ieee80211_add_key(struct wiphy *wiphy, struct net_device *dev,
-			     u8 key_idx, const u8 *mac_addr,
+			     u8 key_idx, bool pairwise, const u8 *mac_addr,
 			     struct key_params *params)
 {
 	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
@@ -131,6 +131,9 @@ static int ieee80211_add_key(struct wiphy *wiphy, struct net_device *dev,
 	if (IS_ERR(key))
 		return PTR_ERR(key);
 
+	if (pairwise)
+		key->conf.flags |= IEEE80211_KEY_FLAG_PAIRWISE;
+
 	mutex_lock(&sdata->local->sta_mtx);
 
 	if (mac_addr) {
@@ -153,7 +156,7 @@ static int ieee80211_add_key(struct wiphy *wiphy, struct net_device *dev,
 }
 
 static int ieee80211_del_key(struct wiphy *wiphy, struct net_device *dev,
-			     u8 key_idx, const u8 *mac_addr)
+			     u8 key_idx, bool pairwise, const u8 *mac_addr)
 {
 	struct ieee80211_sub_if_data *sdata;
 	struct sta_info *sta;
@@ -170,10 +173,17 @@ static int ieee80211_del_key(struct wiphy *wiphy, struct net_device *dev,
 		if (!sta)
 			goto out_unlock;
 
-		if (sta->key) {
-			ieee80211_key_free(sdata->local, sta->key);
-			WARN_ON(sta->key);
-			ret = 0;
+		if (pairwise) {
+			if (sta->ptk) {
+				ieee80211_key_free(sdata->local, sta->ptk);
+				ret = 0;
+			}
+		} else {
+			if (sta->gtk[key_idx]) {
+				ieee80211_key_free(sdata->local,
+						   sta->gtk[key_idx]);
+				ret = 0;
+			}
 		}
 
 		goto out_unlock;
@@ -195,7 +205,8 @@ static int ieee80211_del_key(struct wiphy *wiphy, struct net_device *dev,
 }
 
 static int ieee80211_get_key(struct wiphy *wiphy, struct net_device *dev,
-			     u8 key_idx, const u8 *mac_addr, void *cookie,
+			     u8 key_idx, bool pairwise, const u8 *mac_addr,
+			     void *cookie,
 			     void (*callback)(void *cookie,
 					      struct key_params *params))
 {
@@ -203,7 +214,7 @@ static int ieee80211_get_key(struct wiphy *wiphy, struct net_device *dev,
 	struct sta_info *sta = NULL;
 	u8 seq[6] = {0};
 	struct key_params params;
-	struct ieee80211_key *key;
+	struct ieee80211_key *key = NULL;
 	u32 iv32;
 	u16 iv16;
 	int err = -ENOENT;
@@ -217,7 +228,10 @@ static int ieee80211_get_key(struct wiphy *wiphy, struct net_device *dev,
 		if (!sta)
 			goto out;
 
-		key = sta->key;
+		if (pairwise)
+			key = sta->ptk;
+		else if (key_idx < NUM_DEFAULT_KEYS)
+			key = sta->gtk[key_idx];
 	} else
 		key = sdata->keys[key_idx];
 
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 76c2b50..f0610fa 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -549,8 +549,6 @@ struct ieee80211_sub_if_data {
 	struct ieee80211_fragment_entry	fragments[IEEE80211_FRAGMENT_MAX];
 	unsigned int fragment_next;
 
-#define NUM_DEFAULT_KEYS 4
-#define NUM_DEFAULT_MGMT_KEYS 2
 	struct ieee80211_key *keys[NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS];
 	struct ieee80211_key *default_key;
 	struct ieee80211_key *default_mgmt_key;
diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index 6a63d1a..ccd676b 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -68,15 +68,21 @@ static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
 
 	might_sleep();
 
-	if (!key->local->ops->set_key) {
-		ret = -EOPNOTSUPP;
+	if (!key->local->ops->set_key)
 		goto out_unsupported;
-	}
 
 	assert_key_lock(key->local);
 
 	sta = get_sta_for_key(key);
 
+	/*
+	 * If this is a per-STA GTK, check if it
+	 * is supported; if not, return.
+	 */
+	if (sta && !(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE) &&
+	    !(key->local->hw.flags & IEEE80211_HW_SUPPORTS_PER_STA_GTK))
+		goto out_unsupported;
+
 	sdata = key->sdata;
 	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
 		sdata = container_of(sdata->bss,
@@ -85,31 +91,28 @@ static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
 
 	ret = drv_set_key(key->local, SET_KEY, sdata, sta, &key->conf);
 
-	if (!ret)
+	if (!ret) {
 		key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
+		return 0;
+	}
 
-	if (ret && ret != -ENOSPC && ret != -EOPNOTSUPP)
+	if (ret != -ENOSPC && ret != -EOPNOTSUPP)
 		wiphy_err(key->local->hw.wiphy,
 			  "failed to set key (%d, %pM) to hardware (%d)\n",
 			  key->conf.keyidx, sta ? sta->addr : bcast_addr, ret);
 
-out_unsupported:
-	if (ret) {
-		switch (key->conf.cipher) {
-		case WLAN_CIPHER_SUITE_WEP40:
-		case WLAN_CIPHER_SUITE_WEP104:
-		case WLAN_CIPHER_SUITE_TKIP:
-		case WLAN_CIPHER_SUITE_CCMP:
-		case WLAN_CIPHER_SUITE_AES_CMAC:
-			/* all of these we can do in software */
-			ret = 0;
-			break;
-		default:
-			ret = -EINVAL;
-		}
+ out_unsupported:
+	switch (key->conf.cipher) {
+	case WLAN_CIPHER_SUITE_WEP40:
+	case WLAN_CIPHER_SUITE_WEP104:
+	case WLAN_CIPHER_SUITE_TKIP:
+	case WLAN_CIPHER_SUITE_CCMP:
+	case WLAN_CIPHER_SUITE_AES_CMAC:
+		/* all of these we can do in software */
+		return 0;
+	default:
+		return -EINVAL;
 	}
-
-	return ret;
 }
 
 static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
@@ -147,6 +150,26 @@ static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
 	key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
 }
 
+void ieee80211_key_removed(struct ieee80211_key_conf *key_conf)
+{
+	struct ieee80211_key *key;
+
+	key = container_of(key_conf, struct ieee80211_key, conf);
+
+	might_sleep();
+	assert_key_lock(key->local);
+
+	key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
+
+	/*
+	 * Flush TX path to avoid attempts to use this key
+	 * after this function returns. Until then, drivers
+	 * must be prepared to handle the key.
+	 */
+	synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(ieee80211_key_removed);
+
 static void __ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata,
 					int idx)
 {
@@ -202,6 +225,7 @@ void ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata,
 
 static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
 				    struct sta_info *sta,
+				    bool pairwise,
 				    struct ieee80211_key *old,
 				    struct ieee80211_key *new)
 {
@@ -210,8 +234,14 @@ static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
 	if (new)
 		list_add(&new->list, &sdata->key_list);
 
-	if (sta) {
-		rcu_assign_pointer(sta->key, new);
+	if (sta && pairwise) {
+		rcu_assign_pointer(sta->ptk, new);
+	} else if (sta) {
+		if (old)
+			idx = old->conf.keyidx;
+		else
+			idx = new->conf.keyidx;
+		rcu_assign_pointer(sta->gtk[idx], new);
 	} else {
 		WARN_ON(new && old && new->conf.keyidx != old->conf.keyidx);
 
@@ -355,6 +385,7 @@ int ieee80211_key_link(struct ieee80211_key *key,
 {
 	struct ieee80211_key *old_key;
 	int idx, ret;
+	bool pairwise = key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE;
 
 	BUG_ON(!sdata);
 	BUG_ON(!key);
@@ -371,13 +402,6 @@ int ieee80211_key_link(struct ieee80211_key *key,
 		 */
 		if (test_sta_flags(sta, WLAN_STA_WME))
 			key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
-
-		/*
-		 * This key is for a specific sta interface,
-		 * inform the driver that it should try to store
-		 * this key as pairwise key.
-		 */
-		key->conf.flags |= IEEE80211_KEY_FLAG_PAIRWISE;
 	} else {
 		if (sdata->vif.type == NL80211_IFTYPE_STATION) {
 			struct sta_info *ap;
@@ -399,12 +423,14 @@ int ieee80211_key_link(struct ieee80211_key *key,
 
 	mutex_lock(&sdata->local->key_mtx);
 
-	if (sta)
-		old_key = sta->key;
+	if (sta && pairwise)
+		old_key = sta->ptk;
+	else if (sta)
+		old_key = sta->gtk[idx];
 	else
 		old_key = sdata->keys[idx];
 
-	__ieee80211_key_replace(sdata, sta, old_key, key);
+	__ieee80211_key_replace(sdata, sta, pairwise, old_key, key);
 	__ieee80211_key_destroy(old_key);
 
 	ieee80211_debugfs_key_add(key);
@@ -423,7 +449,8 @@ static void __ieee80211_key_free(struct ieee80211_key *key)
 	 */
 	if (key->sdata)
 		__ieee80211_key_replace(key->sdata, key->sta,
-					key, NULL);
+				key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE,
+				key, NULL);
 	__ieee80211_key_destroy(key);
 }
 
diff --git a/net/mac80211/key.h b/net/mac80211/key.h
index cb9a4a6..0db1c0f 100644
--- a/net/mac80211/key.h
+++ b/net/mac80211/key.h
@@ -16,6 +16,9 @@
 #include <linux/rcupdate.h>
 #include <net/mac80211.h>
 
+#define NUM_DEFAULT_KEYS 4
+#define NUM_DEFAULT_MGMT_KEYS 2
+
 #define WEP_IV_LEN		4
 #define WEP_ICV_LEN		4
 #define ALG_TKIP_KEY_LEN	32
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index b3e161f..b67221d 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -846,7 +846,7 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
 	int keyidx;
 	int hdrlen;
 	ieee80211_rx_result result = RX_DROP_UNUSABLE;
-	struct ieee80211_key *stakey = NULL;
+	struct ieee80211_key *sta_ptk = NULL;
 	int mmie_keyidx = -1;
 	__le16 fc;
 
@@ -888,15 +888,15 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
 	rx->key = NULL;
 
 	if (rx->sta)
-		stakey = rcu_dereference(rx->sta->key);
+		sta_ptk = rcu_dereference(rx->sta->ptk);
 
 	fc = hdr->frame_control;
 
 	if (!ieee80211_has_protected(fc))
 		mmie_keyidx = ieee80211_get_mmie_keyidx(rx->skb);
 
-	if (!is_multicast_ether_addr(hdr->addr1) && stakey) {
-		rx->key = stakey;
+	if (!is_multicast_ether_addr(hdr->addr1) && sta_ptk) {
+		rx->key = sta_ptk;
 		if ((status->flag & RX_FLAG_DECRYPTED) &&
 		    (status->flag & RX_FLAG_IV_STRIPPED))
 			return RX_CONTINUE;
@@ -912,7 +912,10 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
 		if (mmie_keyidx < NUM_DEFAULT_KEYS ||
 		    mmie_keyidx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
 			return RX_DROP_MONITOR; /* unexpected BIP keyidx */
-		rx->key = rcu_dereference(rx->sdata->keys[mmie_keyidx]);
+		if (rx->sta)
+			rx->key = rcu_dereference(rx->sta->gtk[mmie_keyidx]);
+		if (!rx->key)
+			rx->key = rcu_dereference(rx->sdata->keys[mmie_keyidx]);
 	} else if (!ieee80211_has_protected(fc)) {
 		/*
 		 * The frame was not protected, so skip decryption. However, we
@@ -955,17 +958,25 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
 		skb_copy_bits(rx->skb, hdrlen + 3, &keyid, 1);
 		keyidx = keyid >> 6;
 
-		rx->key = rcu_dereference(rx->sdata->keys[keyidx]);
+		/* check per-station GTK first, if multicast packet */
+		if (is_multicast_ether_addr(hdr->addr1) && rx->sta)
+			rx->key = rcu_dereference(rx->sta->gtk[keyidx]);
 
-		/*
-		 * RSNA-protected unicast frames should always be sent with
-		 * pairwise or station-to-station keys, but for WEP we allow
-		 * using a key index as well.
-		 */
-		if (rx->key && rx->key->conf.cipher != WLAN_CIPHER_SUITE_WEP40 &&
-		    rx->key->conf.cipher != WLAN_CIPHER_SUITE_WEP104 &&
-		    !is_multicast_ether_addr(hdr->addr1))
-			rx->key = NULL;
+		/* if not found, try default key */
+		if (!rx->key) {
+			rx->key = rcu_dereference(rx->sdata->keys[keyidx]);
+
+			/*
+			 * RSNA-protected unicast frames should always be
+			 * sent with pairwise or station-to-station keys,
+			 * but for WEP we allow using a key index as well.
+			 */
+			if (rx->key &&
+			    rx->key->conf.cipher != WLAN_CIPHER_SUITE_WEP40 &&
+			    rx->key->conf.cipher != WLAN_CIPHER_SUITE_WEP104 &&
+			    !is_multicast_ether_addr(hdr->addr1))
+				rx->key = NULL;
+		}
 	}
 
 	if (rx->key) {
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index aeaf2d6..6d8f897 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -616,7 +616,7 @@ static int __must_check __sta_info_destroy(struct sta_info *sta)
 	struct ieee80211_sub_if_data *sdata;
 	struct sk_buff *skb;
 	unsigned long flags;
-	int ret;
+	int ret, i;
 
 	might_sleep();
 
@@ -644,10 +644,10 @@ static int __must_check __sta_info_destroy(struct sta_info *sta)
 	if (ret)
 		return ret;
 
-	if (sta->key) {
-		ieee80211_key_free(local, sta->key);
-		WARN_ON(sta->key);
-	}
+	for (i = 0; i < NUM_DEFAULT_KEYS; i++)
+		ieee80211_key_free(local, sta->gtk[i]);
+	if (sta->ptk)
+		ieee80211_key_free(local, sta->ptk);
 
 	sta->dead = true;
 
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index cf21a2e..9265aca 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -199,7 +199,8 @@ enum plink_state {
  * @hnext: hash table linked list pointer
  * @local: pointer to the global information
  * @sdata: virtual interface this station belongs to
- * @key: peer key negotiated with this station, if any
+ * @ptk: peer key negotiated with this station, if any
+ * @gtk: group keys negotiated with this station, if any
  * @rate_ctrl: rate control algorithm reference
  * @rate_ctrl_priv: rate control private per-STA pointer
  * @last_tx_rate: rate used for last transmit, to report to userspace as
@@ -254,7 +255,8 @@ struct sta_info {
 	struct sta_info *hnext;
 	struct ieee80211_local *local;
 	struct ieee80211_sub_if_data *sdata;
-	struct ieee80211_key *key;
+	struct ieee80211_key *gtk[NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS];
+	struct ieee80211_key *ptk;
 	struct rate_control_ref *rate_ctrl;
 	void *rate_ctrl_priv;
 	spinlock_t lock;
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 258fbdb..96c5943 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -532,7 +532,7 @@ ieee80211_tx_h_select_key(struct ieee80211_tx_data *tx)
 
 	if (unlikely(info->flags & IEEE80211_TX_INTFL_DONT_ENCRYPT))
 		tx->key = NULL;
-	else if (tx->sta && (key = rcu_dereference(tx->sta->key)))
+	else if (tx->sta && (key = rcu_dereference(tx->sta->ptk)))
 		tx->key = key;
 	else if (ieee80211_is_mgmt(hdr->frame_control) &&
 		 is_multicast_ether_addr(hdr->addr1) &&