cfg80211: fix error path in cfg80211_wext_siwscan

If there's an invalid channel or SSID, the code leaks
the scan request. Always free the scan request, unless
it was successfully given to the driver.

Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 12dfa62..0c2cbbe 100644 (file)
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -601,7 +601,7 @@ int cfg80211_wext_siwscan(struct net_device *dev,
        struct cfg80211_registered_device *rdev;
        struct wiphy *wiphy;
        struct iw_scan_req *wreq = NULL;
-       struct cfg80211_scan_request *creq;
+       struct cfg80211_scan_request *creq = NULL;
        int i, err, n_channels = 0;
        enum ieee80211_band band;
 
@@ -694,8 +694,10 @@ int cfg80211_wext_siwscan(struct net_device *dev,
        /* translate "Scan for SSID" request */
        if (wreq) {
                if (wrqu->data.flags & IW_SCAN_THIS_ESSID) {
-                       if (wreq->essid_len > IEEE80211_MAX_SSID_LEN)
-                               return -EINVAL;
+                       if (wreq->essid_len > IEEE80211_MAX_SSID_LEN) {
+                               err = -EINVAL;
+                               goto out;
+                       }
                        memcpy(creq->ssids[0].ssid, wreq->essid, wreq->essid_len);
                        creq->ssids[0].ssid_len = wreq->essid_len;
                }
@@ -707,12 +709,15 @@ int cfg80211_wext_siwscan(struct net_device *dev,
        err = rdev->ops->scan(wiphy, dev, creq);
        if (err) {
                rdev->scan_req = NULL;
-               kfree(creq);
+               /* creq will be freed below */
        } else {
                nl80211_send_scan_start(rdev, dev);
+               /* creq now owned by driver */
+               creq = NULL;
                dev_hold(dev);
        }
  out:
+       kfree(creq);
        cfg80211_unlock_rdev(rdev);
        return err;
 }