mac80211: support separate default keys
[linux-2.6.git] / net / mac80211 / key.c
index 92d994f..84cf919 100644 (file)
  * Copyright 2002-2005, Instant802 Networks, Inc.
  * Copyright 2005-2006, Devicescape Software, Inc.
  * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
+ * Copyright 2007-2008 Johannes Berg <johannes@sipsolutions.net>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */
 
+#include <linux/if_ether.h>
+#include <linux/etherdevice.h>
+#include <linux/list.h>
+#include <linux/rcupdate.h>
+#include <linux/rtnetlink.h>
+#include <linux/slab.h>
 #include <net/mac80211.h>
 #include "ieee80211_i.h"
+#include "driver-ops.h"
 #include "debugfs_key.h"
 #include "aes_ccm.h"
+#include "aes_cmac.h"
 
-struct ieee80211_key *ieee80211_key_alloc(struct ieee80211_sub_if_data *sdata,
-                                         int idx, size_t key_len, gfp_t flags)
+
+/**
+ * DOC: Key handling basics
+ *
+ * Key handling in mac80211 is done based on per-interface (sub_if_data)
+ * keys and per-station keys. Since each station belongs to an interface,
+ * each station key also belongs to that interface.
+ *
+ * Hardware acceleration is done on a best-effort basis, for each key
+ * that is eligible the hardware is asked to enable that key but if
+ * it cannot do that they key is simply kept for software encryption.
+ * There is currently no way of knowing this except by looking into
+ * debugfs.
+ *
+ * All key operations are protected internally.
+ *
+ * Within mac80211, key references are, just as STA structure references,
+ * protected by RCU. Note, however, that some things are unprotected,
+ * namely the key->sta dereferences within the hardware acceleration
+ * functions. This means that sta_info_destroy() must remove the key
+ * which waits for an RCU grace period.
+ */
+
+static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
+
+static void assert_key_lock(struct ieee80211_local *local)
+{
+       lockdep_assert_held(&local->key_mtx);
+}
+
+static struct ieee80211_sta *get_sta_for_key(struct ieee80211_key *key)
+{
+       if (key->sta)
+               return &key->sta->sta;
+
+       return NULL;
+}
+
+static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
+{
+       struct ieee80211_sub_if_data *sdata;
+       struct ieee80211_sta *sta;
+       int ret;
+
+       might_sleep();
+
+       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) {
+               /*
+                * The driver doesn't know anything about VLAN interfaces.
+                * Hence, don't send GTKs for VLAN interfaces to the driver.
+                */
+               if (!(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE))
+                       goto out_unsupported;
+               sdata = container_of(sdata->bss,
+                                    struct ieee80211_sub_if_data,
+                                    u.ap);
+       }
+
+       ret = drv_set_key(key->local, SET_KEY, sdata, sta, &key->conf);
+
+       if (!ret) {
+               key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
+               return 0;
+       }
+
+       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:
+       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;
+       }
+}
+
+static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
+{
+       struct ieee80211_sub_if_data *sdata;
+       struct ieee80211_sta *sta;
+       int ret;
+
+       might_sleep();
+
+       if (!key || !key->local->ops->set_key)
+               return;
+
+       assert_key_lock(key->local);
+
+       if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
+               return;
+
+       sta = get_sta_for_key(key);
+       sdata = key->sdata;
+
+       if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
+               sdata = container_of(sdata->bss,
+                                    struct ieee80211_sub_if_data,
+                                    u.ap);
+
+       ret = drv_set_key(key->local, DISABLE_KEY, sdata,
+                         sta, &key->conf);
+
+       if (ret)
+               wiphy_err(key->local->hw.wiphy,
+                         "failed to remove key (%d, %pM) from hardware (%d)\n",
+                         key->conf.keyidx, sta ? sta->addr : bcast_addr, ret);
+
+       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, bool uni, bool multi)
+{
+       struct ieee80211_key *key = NULL;
+
+       assert_key_lock(sdata->local);
+
+       if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
+               key = sdata->keys[idx];
+
+       if (uni)
+               rcu_assign_pointer(sdata->default_unicast_key, key);
+       if (multi)
+               rcu_assign_pointer(sdata->default_multicast_key, key);
+
+       ieee80211_debugfs_key_update_default(sdata);
+}
+
+void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx,
+                              bool uni, bool multi)
+{
+       mutex_lock(&sdata->local->key_mtx);
+       __ieee80211_set_default_key(sdata, idx, uni, multi);
+       mutex_unlock(&sdata->local->key_mtx);
+}
+
+static void
+__ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata, int idx)
+{
+       struct ieee80211_key *key = NULL;
+
+       assert_key_lock(sdata->local);
+
+       if (idx >= NUM_DEFAULT_KEYS &&
+           idx < NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
+               key = sdata->keys[idx];
+
+       rcu_assign_pointer(sdata->default_mgmt_key, key);
+
+       ieee80211_debugfs_key_update_default(sdata);
+}
+
+void ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata,
+                                   int idx)
+{
+       mutex_lock(&sdata->local->key_mtx);
+       __ieee80211_set_default_mgmt_key(sdata, idx);
+       mutex_unlock(&sdata->local->key_mtx);
+}
+
+
+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)
+{
+       int idx;
+       bool defunikey, defmultikey, defmgmtkey;
+
+       if (new)
+               list_add(&new->list, &sdata->key_list);
+
+       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);
+
+               if (old)
+                       idx = old->conf.keyidx;
+               else
+                       idx = new->conf.keyidx;
+
+               defunikey = old && sdata->default_unicast_key == old;
+               defmultikey = old && sdata->default_multicast_key == old;
+               defmgmtkey = old && sdata->default_mgmt_key == old;
+
+               if (defunikey && !new)
+                       __ieee80211_set_default_key(sdata, -1, true, false);
+               if (defmultikey && !new)
+                       __ieee80211_set_default_key(sdata, -1, false, true);
+               if (defmgmtkey && !new)
+                       __ieee80211_set_default_mgmt_key(sdata, -1);
+
+               rcu_assign_pointer(sdata->keys[idx], new);
+               if (defunikey && new)
+                       __ieee80211_set_default_key(sdata, new->conf.keyidx,
+                                                   true, false);
+               if (defmultikey && new)
+                       __ieee80211_set_default_key(sdata, new->conf.keyidx,
+                                                   false, true);
+               if (defmgmtkey && new)
+                       __ieee80211_set_default_mgmt_key(sdata,
+                                                        new->conf.keyidx);
+       }
+
+       if (old) {
+               /*
+                * We'll use an empty list to indicate that the key
+                * has already been removed.
+                */
+               list_del_init(&old->list);
+       }
+}
+
+struct ieee80211_key *ieee80211_key_alloc(u32 cipher, int idx, size_t key_len,
+                                         const u8 *key_data,
+                                         size_t seq_len, const u8 *seq)
 {
        struct ieee80211_key *key;
+       int i, j, err;
 
-       key = kzalloc(sizeof(struct ieee80211_key) + key_len, flags);
+       BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS);
+
+       key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
        if (!key)
-               return NULL;
-       kref_init(&key->kref);
+               return ERR_PTR(-ENOMEM);
+
+       /*
+        * Default to software encryption; we'll later upload the
+        * key to the hardware if possible.
+        */
+       key->conf.flags = 0;
+       key->flags = 0;
+
+       key->conf.cipher = cipher;
+       key->conf.keyidx = idx;
+       key->conf.keylen = key_len;
+       switch (cipher) {
+       case WLAN_CIPHER_SUITE_WEP40:
+       case WLAN_CIPHER_SUITE_WEP104:
+               key->conf.iv_len = WEP_IV_LEN;
+               key->conf.icv_len = WEP_ICV_LEN;
+               break;
+       case WLAN_CIPHER_SUITE_TKIP:
+               key->conf.iv_len = TKIP_IV_LEN;
+               key->conf.icv_len = TKIP_ICV_LEN;
+               if (seq) {
+                       for (i = 0; i < NUM_RX_DATA_QUEUES; i++) {
+                               key->u.tkip.rx[i].iv32 =
+                                       get_unaligned_le32(&seq[2]);
+                               key->u.tkip.rx[i].iv16 =
+                                       get_unaligned_le16(seq);
+                       }
+               }
+               break;
+       case WLAN_CIPHER_SUITE_CCMP:
+               key->conf.iv_len = CCMP_HDR_LEN;
+               key->conf.icv_len = CCMP_MIC_LEN;
+               if (seq) {
+                       for (i = 0; i < NUM_RX_DATA_QUEUES + 1; i++)
+                               for (j = 0; j < CCMP_PN_LEN; j++)
+                                       key->u.ccmp.rx_pn[i][j] =
+                                               seq[CCMP_PN_LEN - j - 1];
+               }
+               /*
+                * Initialize AES key state here as an optimization so that
+                * it does not need to be initialized for every packet.
+                */
+               key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
+               if (IS_ERR(key->u.ccmp.tfm)) {
+                       err = PTR_ERR(key->u.ccmp.tfm);
+                       kfree(key);
+                       key = ERR_PTR(err);
+               }
+               break;
+       case WLAN_CIPHER_SUITE_AES_CMAC:
+               key->conf.iv_len = 0;
+               key->conf.icv_len = sizeof(struct ieee80211_mmie);
+               if (seq)
+                       for (j = 0; j < 6; j++)
+                               key->u.aes_cmac.rx_pn[j] = seq[6 - j - 1];
+               /*
+                * Initialize AES key state here as an optimization so that
+                * it does not need to be initialized for every packet.
+                */
+               key->u.aes_cmac.tfm =
+                       ieee80211_aes_cmac_key_setup(key_data);
+               if (IS_ERR(key->u.aes_cmac.tfm)) {
+                       err = PTR_ERR(key->u.aes_cmac.tfm);
+                       kfree(key);
+                       key = ERR_PTR(err);
+               }
+               break;
+       }
+       memcpy(key->conf.key, key_data, key_len);
+       INIT_LIST_HEAD(&key->list);
+
        return key;
 }
 
-static void ieee80211_key_release(struct kref *kref)
+static void __ieee80211_key_destroy(struct ieee80211_key *key)
 {
-       struct ieee80211_key *key;
+       if (!key)
+               return;
 
-       key = container_of(kref, struct ieee80211_key, kref);
-       if (key->conf.alg == ALG_CCMP)
+       if (key->local)
+               ieee80211_key_disable_hw_accel(key);
+
+       if (key->conf.cipher == WLAN_CIPHER_SUITE_CCMP)
                ieee80211_aes_key_free(key->u.ccmp.tfm);
-       ieee80211_debugfs_key_remove(key);
+       if (key->conf.cipher == WLAN_CIPHER_SUITE_AES_CMAC)
+               ieee80211_aes_cmac_key_free(key->u.aes_cmac.tfm);
+       if (key->local)
+               ieee80211_debugfs_key_remove(key);
+
        kfree(key);
 }
 
-void ieee80211_key_free(struct ieee80211_key *key)
+int ieee80211_key_link(struct ieee80211_key *key,
+                      struct ieee80211_sub_if_data *sdata,
+                      struct sta_info *sta)
+{
+       struct ieee80211_key *old_key;
+       int idx, ret;
+       bool pairwise = key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE;
+
+       BUG_ON(!sdata);
+       BUG_ON(!key);
+
+       idx = key->conf.keyidx;
+       key->local = sdata->local;
+       key->sdata = sdata;
+       key->sta = sta;
+
+       if (sta) {
+               /*
+                * some hardware cannot handle TKIP with QoS, so
+                * we indicate whether QoS could be in use.
+                */
+               if (test_sta_flags(sta, WLAN_STA_WME))
+                       key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
+       } else {
+               if (sdata->vif.type == NL80211_IFTYPE_STATION) {
+                       struct sta_info *ap;
+
+                       /*
+                        * We're getting a sta pointer in,
+                        * so must be under RCU read lock.
+                        */
+
+                       /* same here, the AP could be using QoS */
+                       ap = sta_info_get(key->sdata, key->sdata->u.mgd.bssid);
+                       if (ap) {
+                               if (test_sta_flags(ap, WLAN_STA_WME))
+                                       key->conf.flags |=
+                                               IEEE80211_KEY_FLAG_WMM_STA;
+                       }
+               }
+       }
+
+       mutex_lock(&sdata->local->key_mtx);
+
+       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, pairwise, old_key, key);
+       __ieee80211_key_destroy(old_key);
+
+       ieee80211_debugfs_key_add(key);
+
+       ret = ieee80211_key_enable_hw_accel(key);
+
+       mutex_unlock(&sdata->local->key_mtx);
+
+       return ret;
+}
+
+static void __ieee80211_key_free(struct ieee80211_key *key)
 {
-       if (key)
-               kref_put(&key->kref, ieee80211_key_release);
+       /*
+        * Replace key with nothingness if it was ever used.
+        */
+       if (key->sdata)
+               __ieee80211_key_replace(key->sdata, key->sta,
+                               key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE,
+                               key, NULL);
+       __ieee80211_key_destroy(key);
+}
+
+void ieee80211_key_free(struct ieee80211_local *local,
+                       struct ieee80211_key *key)
+{
+       if (!key)
+               return;
+
+       mutex_lock(&local->key_mtx);
+       __ieee80211_key_free(key);
+       mutex_unlock(&local->key_mtx);
+}
+
+void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
+{
+       struct ieee80211_key *key;
+
+       ASSERT_RTNL();
+
+       if (WARN_ON(!ieee80211_sdata_running(sdata)))
+               return;
+
+       mutex_lock(&sdata->local->key_mtx);
+
+       list_for_each_entry(key, &sdata->key_list, list)
+               ieee80211_key_enable_hw_accel(key);
+
+       mutex_unlock(&sdata->local->key_mtx);
+}
+
+void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
+{
+       struct ieee80211_key *key;
+
+       ASSERT_RTNL();
+
+       mutex_lock(&sdata->local->key_mtx);
+
+       list_for_each_entry(key, &sdata->key_list, list)
+               ieee80211_key_disable_hw_accel(key);
+
+       mutex_unlock(&sdata->local->key_mtx);
+}
+
+void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
+{
+       struct ieee80211_key *key, *tmp;
+
+       mutex_lock(&sdata->local->key_mtx);
+
+       ieee80211_debugfs_key_remove_mgmt_default(sdata);
+
+       list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
+               __ieee80211_key_free(key);
+
+       ieee80211_debugfs_key_update_default(sdata);
+
+       mutex_unlock(&sdata->local->key_mtx);
 }