From ef044763a3ca6b9e0bb65a9ce0cb38c0eca62756 Mon Sep 17 00:00:00 2001 From: Eliad Peller Date: Tue, 17 Nov 2015 10:24:37 +0200 Subject: [PATCH] mac80211: add atomic uploaded keys iterator add ieee80211_iter_keys_rcu() to iterate over uploaded keys in atomic context (when rcu is locked) The station removal code removes the keys only after calling synchronize_net(), so it's not safe to iterate the keys at this point (and postponing the actual key deletion with call_rcu() might result in some badly-ordered ops calls). Add a flag to indicate a station is being removed, and skip the configured keys if it's set. Signed-off-by: Eliad Peller Signed-off-by: Emmanuel Grumbach Signed-off-by: Johannes Berg --- include/net/mac80211.h | 24 ++++++++++++++++++ net/mac80211/key.c | 56 ++++++++++++++++++++++++++++++++++++++--- net/mac80211/sta_info.c | 1 + net/mac80211/sta_info.h | 2 ++ 4 files changed, 79 insertions(+), 4 deletions(-) diff --git a/include/net/mac80211.h b/include/net/mac80211.h index 18ac733afc91..a68051c41ac3 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -4917,6 +4917,30 @@ void ieee80211_iter_keys(struct ieee80211_hw *hw, void *data), void *iter_data); +/** + * ieee80211_iter_keys_rcu - iterate keys programmed into the device + * @hw: pointer obtained from ieee80211_alloc_hw() + * @vif: virtual interface to iterate, may be %NULL for all + * @iter: iterator function that will be called for each key + * @iter_data: custom data to pass to the iterator function + * + * This function can be used to iterate all the keys known to + * mac80211, even those that weren't previously programmed into + * the device. Note that due to locking reasons, keys of station + * in removal process will be skipped. + * + * This function requires being called in an RCU critical section, + * and thus iter must be atomic. + */ +void ieee80211_iter_keys_rcu(struct ieee80211_hw *hw, + struct ieee80211_vif *vif, + void (*iter)(struct ieee80211_hw *hw, + struct ieee80211_vif *vif, + struct ieee80211_sta *sta, + struct ieee80211_key_conf *key, + void *data), + void *iter_data); + /** * ieee80211_iter_chan_contexts_atomic - iterate channel contexts * @hw: pointre obtained from ieee80211_alloc_hw(). diff --git a/net/mac80211/key.c b/net/mac80211/key.c index 44388d6a1d8e..5e5bc599da4c 100644 --- a/net/mac80211/key.c +++ b/net/mac80211/key.c @@ -4,6 +4,7 @@ * Copyright 2006-2007 Jiri Benc * Copyright 2007-2008 Johannes Berg * Copyright 2013-2014 Intel Mobile Communications GmbH + * Copyright 2015 Intel Deutschland GmbH * * 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 @@ -320,7 +321,7 @@ static void ieee80211_key_replace(struct ieee80211_sub_if_data *sdata, return; if (new) - list_add_tail(&new->list, &sdata->key_list); + list_add_tail_rcu(&new->list, &sdata->key_list); WARN_ON(new && old && new->conf.keyidx != old->conf.keyidx); @@ -368,7 +369,7 @@ static void ieee80211_key_replace(struct ieee80211_sub_if_data *sdata, } if (old) - list_del(&old->list); + list_del_rcu(&old->list); } struct ieee80211_key * @@ -592,8 +593,8 @@ static void ieee80211_key_destroy(struct ieee80211_key *key, return; /* - * Synchronize so the TX path can no longer be using - * this key before we free/remove it. + * Synchronize so the TX path and rcu key iterators + * can no longer be using this key before we free/remove it. */ synchronize_net(); @@ -744,6 +745,53 @@ void ieee80211_iter_keys(struct ieee80211_hw *hw, } EXPORT_SYMBOL(ieee80211_iter_keys); +static void +_ieee80211_iter_keys_rcu(struct ieee80211_hw *hw, + struct ieee80211_sub_if_data *sdata, + void (*iter)(struct ieee80211_hw *hw, + struct ieee80211_vif *vif, + struct ieee80211_sta *sta, + struct ieee80211_key_conf *key, + void *data), + void *iter_data) +{ + struct ieee80211_key *key; + + list_for_each_entry_rcu(key, &sdata->key_list, list) { + /* skip keys of station in removal process */ + if (key->sta && key->sta->removed) + continue; + if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE)) + continue; + + iter(hw, &sdata->vif, + key->sta ? &key->sta->sta : NULL, + &key->conf, iter_data); + } +} + +void ieee80211_iter_keys_rcu(struct ieee80211_hw *hw, + struct ieee80211_vif *vif, + void (*iter)(struct ieee80211_hw *hw, + struct ieee80211_vif *vif, + struct ieee80211_sta *sta, + struct ieee80211_key_conf *key, + void *data), + void *iter_data) +{ + struct ieee80211_local *local = hw_to_local(hw); + struct ieee80211_sub_if_data *sdata; + + if (vif) { + sdata = vif_to_sdata(vif); + _ieee80211_iter_keys_rcu(hw, sdata, iter, iter_data); + } else { + list_for_each_entry_rcu(sdata, &local->interfaces, list) + _ieee80211_iter_keys_rcu(hw, sdata, iter, iter_data); + } +} +EXPORT_SYMBOL(ieee80211_iter_keys_rcu); + static void ieee80211_free_keys_iface(struct ieee80211_sub_if_data *sdata, struct list_head *keys) { diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c index 723fa30aafc5..4402ad5b27d1 100644 --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -883,6 +883,7 @@ static int __must_check __sta_info_destroy_part1(struct sta_info *sta) } list_del_rcu(&sta->list); + sta->removed = true; drv_sta_pre_rcu_remove(local, sta->sdata, sta); diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h index 2cafb21b422f..d6051629ed15 100644 --- a/net/mac80211/sta_info.h +++ b/net/mac80211/sta_info.h @@ -367,6 +367,7 @@ DECLARE_EWMA(signal, 1024, 8) * @mesh: mesh STA information * @debugfs: debug filesystem info * @dead: set to true when sta is unlinked + * @removed: set to true when sta is being removed from sta_list * @uploaded: set to true when sta is uploaded to the driver * @sta: station information we share with the driver * @sta_state: duplicates information about station state (for debug) @@ -412,6 +413,7 @@ struct sta_info { u16 listen_interval; bool dead; + bool removed; bool uploaded; -- 2.20.1