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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 <eliadx.peller@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Eliad Peller 2015-11-17 10:24:37 +02:00 committed by Johannes Berg
parent 0ead2510f8
commit ef044763a3
4 changed files with 79 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
include/net/mac80211.h
View File

@ -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().

56
net/mac80211/key.c
View File

@ -4,6 +4,7 @@
* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
* Copyright 2007-2008 Johannes Berg <johannes@sipsolutions.net>
* 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)
{

1
net/mac80211/sta_info.c
View File

@ -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);

2
net/mac80211/sta_info.h
View File

@ -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;