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nl80211: Convert sched_scan_req pointer to RCU pointer

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Because of possible races when accessing sched_scan_req pointer in
rdev, the sched_scan_req is converted to RCU pointer.

Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Jukka Rissanen 2014-12-15 13:25:38 +02:00 committed by Johannes Berg
parent 0f8b824561
commit 31a60ed1e9
5 changed files with 29 additions and 17 deletions
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2
include/net/cfg80211.h
View File

@ -1516,6 +1516,7 @@ struct cfg80211_match_set {
* @mac_addr_mask: MAC address mask used with randomisation, bits that
* are 0 in the mask should be randomised, bits that are 1 should
* be taken from the @mac_addr
* @rcu_head: RCU callback used to free the struct
*/
struct cfg80211_sched_scan_request {
struct cfg80211_ssid *ssids;
@ -1537,6 +1538,7 @@ struct cfg80211_sched_scan_request {
struct wiphy *wiphy;
struct net_device *dev;
unsigned long scan_start;
struct rcu_head rcu_head;
/* keep last */
struct ieee80211_channel *channels[0];

10
net/wireless/core.c
View File

@ -867,6 +867,7 @@ void __cfg80211_leave(struct cfg80211_registered_device *rdev,
struct wireless_dev *wdev)
{
struct net_device *dev = wdev->netdev;
struct cfg80211_sched_scan_request *sched_scan_req;
ASSERT_RTNL();
ASSERT_WDEV_LOCK(wdev);
@ -877,7 +878,8 @@ void __cfg80211_leave(struct cfg80211_registered_device *rdev,
break;
case NL80211_IFTYPE_P2P_CLIENT:
case NL80211_IFTYPE_STATION:
if (rdev->sched_scan_req && dev == rdev->sched_scan_req->dev)
sched_scan_req = rtnl_dereference(rdev->sched_scan_req);
if (sched_scan_req && dev == sched_scan_req->dev)
__cfg80211_stop_sched_scan(rdev, false);
#ifdef CONFIG_CFG80211_WEXT
@ -956,6 +958,7 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct cfg80211_registered_device *rdev;
struct cfg80211_sched_scan_request *sched_scan_req;
if (!wdev)
return NOTIFY_DONE;
@ -1021,8 +1024,9 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
___cfg80211_scan_done(rdev, false);
}
if (WARN_ON(rdev->sched_scan_req &&
rdev->sched_scan_req->dev == wdev->netdev)) {
sched_scan_req = rtnl_dereference(rdev->sched_scan_req);
if (WARN_ON(sched_scan_req &&
sched_scan_req->dev == wdev->netdev)) {
__cfg80211_stop_sched_scan(rdev, false);
}

2
net/wireless/core.h
View File

@ -70,7 +70,7 @@ struct cfg80211_registered_device {
u32 bss_generation;
struct cfg80211_scan_request *scan_req; /* protected by RTNL */
struct sk_buff *scan_msg;
struct cfg80211_sched_scan_request *sched_scan_req;
struct cfg80211_sched_scan_request __rcu *sched_scan_req;
unsigned long suspend_at;
struct work_struct scan_done_wk;
struct work_struct sched_scan_results_wk;

19
net/wireless/nl80211.c
View File

@ -6190,6 +6190,7 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
struct cfg80211_registered_device *rdev = info->user_ptr[0];
struct net_device *dev = info->user_ptr[1];
struct wireless_dev *wdev = dev->ieee80211_ptr;
struct cfg80211_sched_scan_request *sched_scan_req;
int err;
if (!(rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN) ||
@ -6199,27 +6200,29 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
if (rdev->sched_scan_req)
return -EINPROGRESS;
rdev->sched_scan_req = nl80211_parse_sched_scan(&rdev->wiphy, wdev,
info->attrs);
err = PTR_ERR_OR_ZERO(rdev->sched_scan_req);
sched_scan_req = nl80211_parse_sched_scan(&rdev->wiphy, wdev,
info->attrs);
err = PTR_ERR_OR_ZERO(sched_scan_req);
if (err)
goto out_err;
err = rdev_sched_scan_start(rdev, dev, rdev->sched_scan_req);
err = rdev_sched_scan_start(rdev, dev, sched_scan_req);
if (err)
goto out_free;
rdev->sched_scan_req->dev = dev;
rdev->sched_scan_req->wiphy = &rdev->wiphy;
sched_scan_req->dev = dev;
sched_scan_req->wiphy = &rdev->wiphy;
rcu_assign_pointer(rdev->sched_scan_req, sched_scan_req);
nl80211_send_sched_scan(rdev, dev,
NL80211_CMD_START_SCHED_SCAN);
return 0;
out_free:
kfree(rdev->sched_scan_req);
kfree(sched_scan_req);
out_err:
rdev->sched_scan_req = NULL;
return err;
}

13
net/wireless/scan.c
View File

@ -257,7 +257,7 @@ void __cfg80211_sched_scan_results(struct work_struct *wk)
rtnl_lock();
request = rdev->sched_scan_req;
request = rtnl_dereference(rdev->sched_scan_req);
/* we don't have sched_scan_req anymore if the scan is stopping */
if (request) {
@ -279,7 +279,8 @@ void cfg80211_sched_scan_results(struct wiphy *wiphy)
{
trace_cfg80211_sched_scan_results(wiphy);
/* ignore if we're not scanning */
if (wiphy_to_rdev(wiphy)->sched_scan_req)
if (rcu_access_pointer(wiphy_to_rdev(wiphy)->sched_scan_req))
queue_work(cfg80211_wq,
&wiphy_to_rdev(wiphy)->sched_scan_results_wk);
}
@ -308,6 +309,7 @@ EXPORT_SYMBOL(cfg80211_sched_scan_stopped);
int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
bool driver_initiated)
{
struct cfg80211_sched_scan_request *sched_scan_req;
struct net_device *dev;
ASSERT_RTNL();
@ -315,7 +317,8 @@ int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
if (!rdev->sched_scan_req)
return -ENOENT;
dev = rdev->sched_scan_req->dev;
sched_scan_req = rtnl_dereference(rdev->sched_scan_req);
dev = sched_scan_req->dev;
if (!driver_initiated) {
int err = rdev_sched_scan_stop(rdev, dev);
@ -325,8 +328,8 @@ int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
nl80211_send_sched_scan(rdev, dev, NL80211_CMD_SCHED_SCAN_STOPPED);
kfree(rdev->sched_scan_req);
rdev->sched_scan_req = NULL;
RCU_INIT_POINTER(rdev->sched_scan_req, NULL);
kfree_rcu(sched_scan_req, rcu_head);
return 0;
}