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mac80211: split ieee80211_key_alloc/free

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In order to RCU-ify sta_info, we need to be able to allocate
a key without linking it to an sdata/sta structure (because
allocation cannot be done in an rcu critical section). This
patch splits up ieee80211_key_alloc() and updates all users
appropriately.

While at it, this patch fixes a number of race conditions
such as finally making key replacement atomic, unfortunately
at the expense of more complex code.

Note that this patch documents /existing/ bugs with sta info
and key interaction, there is currently a race condition
when a sta info is freed without holding the RTNL. This will
finally be fixed by a followup patch.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Johannes Berg
2008-02-25 16:27:45 +01:00
committed by John W. Linville
parent 6f48422a29
commit db4d1169d0
5 changed files with 209 additions and 104 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
net/mac80211/cfg.c
View File

@@ -123,6 +123,7 @@ static int ieee80211_add_key(struct wiphy *wiphy, struct net_device *dev,
struct sta_info *sta = NULL;
enum ieee80211_key_alg alg;
int ret;
struct ieee80211_key *key;
sdata = IEEE80211_DEV_TO_SUB_IF(dev);
@@ -141,16 +142,21 @@ static int ieee80211_add_key(struct wiphy *wiphy, struct net_device *dev,
return -EINVAL;
}
key = ieee80211_key_alloc(alg, key_idx, params->key_len, params->key);
if (!key)
return -ENOMEM;
if (mac_addr) {
sta = sta_info_get(sdata->local, mac_addr);
if (!sta)
if (!sta) {
ieee80211_key_free(key);
return -ENOENT;
}
}
ieee80211_key_link(key, sdata, sta);
ret = 0;
if (!ieee80211_key_alloc(sdata, sta, alg, key_idx,
params->key_len, params->key))
ret = -ENOMEM;
if (sta)
sta_info_put(sta);
@@ -164,6 +170,7 @@ static int ieee80211_del_key(struct wiphy *wiphy, struct net_device *dev,
struct ieee80211_sub_if_data *sdata;
struct sta_info *sta;
int ret;
struct ieee80211_key *key;
sdata = IEEE80211_DEV_TO_SUB_IF(dev);
@@ -173,9 +180,11 @@ static int ieee80211_del_key(struct wiphy *wiphy, struct net_device *dev,
return -ENOENT;
ret = 0;
if (sta->key)
ieee80211_key_free(sta->key);
else
if (sta->key) {
key = sta->key;
ieee80211_key_free(key);
WARN_ON(sta->key);
} else
ret = -ENOENT;
sta_info_put(sta);
@@ -185,7 +194,9 @@ static int ieee80211_del_key(struct wiphy *wiphy, struct net_device *dev,
if (!sdata->keys[key_idx])
return -ENOENT;
ieee80211_key_free(sdata->keys[key_idx]);
key = sdata->keys[key_idx];
ieee80211_key_free(key);
WARN_ON(sdata->keys[key_idx]);
return 0;
}