/* * 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" /** * 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) 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) { struct ieee80211_key *key = NULL; assert_key_lock(sdata->local); if (idx >= 0 && idx < NUM_DEFAULT_KEYS) key = sdata->keys[idx]; rcu_assign_pointer(sdata->default_key, key); if (key) { ieee80211_debugfs_key_remove_default(key->sdata); ieee80211_debugfs_key_add_default(key->sdata); } } void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx) { mutex_lock(&sdata->local->key_mtx); __ieee80211_set_default_key(sdata, idx); 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); if (key) { ieee80211_debugfs_key_remove_mgmt_default(key->sdata); ieee80211_debugfs_key_add_mgmt_default(key->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, defkey, 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; defkey = old && sdata->default_key == old; defmgmtkey = old && sdata->default_mgmt_key == old; if (defkey && !new) __ieee80211_set_default_key(sdata, -1); if (defmgmtkey && !new) __ieee80211_set_default_mgmt_key(sdata, -1); rcu_assign_pointer(sdata->keys[idx], new); if (defkey && new) __ieee80211_set_default_key(sdata, new->conf.keyidx); 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; 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 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_destroy(struct ieee80211_key *key) { if (!key) return; 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); 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); } 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) { /* * 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_default(sdata); ieee80211_debugfs_key_remove_mgmt_default(sdata); list_for_each_entry_safe(key, tmp, &sdata->key_list, list) __ieee80211_key_free(key); mutex_unlock(&sdata->local->key_mtx); }