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>

1 files changed, 61 insertions, 34 deletions

diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index 6a63d1abd14d..ccd676b2f599 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);
 }