From 3d4f96997263d97cd4d60373f1ed8184ee6df31b Mon Sep 17 00:00:00 2001 From: Ashok Nagarajan Date: Tue, 6 Mar 2012 12:48:30 -0800 Subject: [PATCH] mac80211: Fix potential null pointer dereferencing The patch "{nl,cfg,mac}80211: Implement RSSI threshold for mesh peering" has a potential null pointer dereferencing problem. Thanks to Dan Carpenter for pointing out. This patch will fix the issue. Signed-off-by: Ashok Nagarajan Signed-off-by: John W. Linville --- net/mac80211/mesh_plink.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c index 80ce52772538..4e53c4cbca9e 100644 --- a/net/mac80211/mesh_plink.c +++ b/net/mac80211/mesh_plink.c @@ -31,10 +31,11 @@ #define dot11MeshHoldingTimeout(s) (s->u.mesh.mshcfg.dot11MeshHoldingTimeout) #define dot11MeshMaxPeerLinks(s) (s->u.mesh.mshcfg.dot11MeshMaxPeerLinks) -#define sta_meets_rssi_threshold(sta, sdata) \ +/* We only need a valid sta if user configured a minimum rssi_threshold. */ +#define rssi_threshold_check(sta, sdata) \ (sdata->u.mesh.mshcfg.rssi_threshold == 0 ||\ - (s8) -ewma_read(&sta->avg_signal) > \ - sdata->u.mesh.mshcfg.rssi_threshold) + (sta && (s8) -ewma_read(&sta->avg_signal) > \ + sdata->u.mesh.mshcfg.rssi_threshold)) enum plink_event { PLINK_UNDEFINED, @@ -307,7 +308,7 @@ void mesh_neighbour_update(u8 *hw_addr, u32 rates, sta->plink_state == NL80211_PLINK_LISTEN && sdata->u.mesh.accepting_plinks && sdata->u.mesh.mshcfg.auto_open_plinks && - sta_meets_rssi_threshold(sta, sdata)) + rssi_threshold_check(sta, sdata)) mesh_plink_open(sta); rcu_read_unlock(); @@ -538,9 +539,9 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m } if (ftype == WLAN_SP_MESH_PEERING_OPEN && - !sta_meets_rssi_threshold(sta, sdata)) { + !rssi_threshold_check(sta, sdata)) { mpl_dbg("Mesh plink: %pM does not meet rssi threshold\n", - sta->sta.addr); + mgmt->sa); rcu_read_unlock(); return; }