[PATCH 2/2] Make sure updated BSS entry does not get added twice to the list

[Jouni Malinen]

When the BSS table is being updated based on new scan results, a BSS
entry could end up getting added into last_scan_res list multiple times
if the scan results from the driver includes duplicated values. This
should not happen with driver_nl80211.c since it filter outs duplicates,
but in theory, other driver wrappers could indicate such scan results.
Anyway, it is safer to make sure this cannot happen by explicitly
verifying the last_scan_res list before adding an updated BSS entry
there. A duplicated entry in the list could potentially result in freed
memory being used if there is large enough number of BSSes in the scan
results to cause removal of old BSS entries.

Signed-hostap: Jouni Malinen <jouni at qca.qualcomm.com>

Conflicts:

	wpa_supplicant/bss.c
---
 wpa_supplicant/bss.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/wpa_supplicant/bss.c b/wpa_supplicant/bss.c
index 06e7064..bb11b03 100644
--- a/wpa_supplicant/bss.c
+++ b/wpa_supplicant/bss.c
@@ -597,8 +597,18 @@ void wpa_bss_update_scan_res(struct wpa_supplicant *wpa_s,
 	bss = wpa_bss_get(wpa_s, res->bssid, ssid + 2, ssid[1]);
 	if (bss == NULL)
 		bss = wpa_bss_add(wpa_s, ssid + 2, ssid[1], res);
-	else
+	else {
 		bss = wpa_bss_update(wpa_s, bss, res);
+		if (wpa_s->last_scan_res) {
+			unsigned int i;
+			for (i = 0; i < wpa_s->last_scan_res_used; i++) {
+				if (bss == wpa_s->last_scan_res[i]) {
+					/* Already in the list */
+					return;
+				}
+			}
+		}
+	}
 
 	if (bss == NULL)
 		return;
-- 
1.7.9.5


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