From ccb6c1360f8dd43303c659db718e7e0b24175db5 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 13 Jul 2010 10:55:38 +0200 Subject: [PATCH] cfg80211: don't get expired BSSes When kernel-internal users use cfg80211_get_bss() to get a reference to a BSS struct, they may end up getting one that would have been removed from the list if there had been any userspace access to the list. This leads to inconsistencies and problems. Fix it by making cfg80211_get_bss() ignore BSSes that cfg80211_bss_expire() would remove. Fixes http://bugzilla.intellinuxwireless.org/show_bug.cgi?id=2180 Cc: stable@kernel.org Reported-by: Jiajia Zheng Tested-by: Jiajia Zheng Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- net/wireless/scan.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/wireless/scan.c b/net/wireless/scan.c index 58401d246bda..5ca8c7180141 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -275,6 +275,7 @@ struct cfg80211_bss *cfg80211_get_bss(struct wiphy *wiphy, { struct cfg80211_registered_device *dev = wiphy_to_dev(wiphy); struct cfg80211_internal_bss *bss, *res = NULL; + unsigned long now = jiffies; spin_lock_bh(&dev->bss_lock); @@ -283,6 +284,10 @@ struct cfg80211_bss *cfg80211_get_bss(struct wiphy *wiphy, continue; if (channel && bss->pub.channel != channel) continue; + /* Don't get expired BSS structs */ + if (time_after(now, bss->ts + IEEE80211_SCAN_RESULT_EXPIRE) && + !atomic_read(&bss->hold)) + continue; if (is_bss(&bss->pub, bssid, ssid, ssid_len)) { res = bss; kref_get(&res->ref);