nl80211: Convert sched_scan_req pointer to RCU pointer
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>
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index 4bc1fc9..45d4d72 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -1516,6 +1516,7 @@
* @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 wiphy *wiphy;
struct net_device *dev;
unsigned long scan_start;
+ struct rcu_head rcu_head;
/* keep last */
struct ieee80211_channel *channels[0];
diff --git a/net/wireless/core.c b/net/wireless/core.c
index b661fcc..0743449 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -867,6 +867,7 @@
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 @@
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 @@
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 @@
___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);
}
diff --git a/net/wireless/core.h b/net/wireless/core.h
index e87cae5..e82030c 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -70,7 +70,7 @@
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;
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 5b1907f..bacdf22f 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -6190,6 +6190,7 @@
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 @@
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;
}
diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index bda39f1..c705c3e 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -257,7 +257,7 @@
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 @@
{
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 @@
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 @@
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 @@
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;
}