cfg80211: fix the IE inheritance of extension IEs

Extension IEs have ID 255 followed by extension ID. Current
code is buggy in handling it in two ways:
1. When checking if IE is in the frame, it uses just the ID, which
   for extension elements is too broad.
2. It uses 0xFF to mark copied IEs, which will result in not copying
   extension IEs from the subelement.

Fix both issue.
Signed-off-by: Sara Sharon <sara.sharon@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/scan.c

@@ -216,7 +216,13 @@ static size_t cfg80211_gen_new_ie(const u8 *ie, size_t ielen,
 			continue;
 		}
 
-		tmp = (u8 *)cfg80211_find_ie(tmp_old[0], sub_copy, subie_len);
+		if (tmp_old[0] == WLAN_EID_EXTENSION)
+			tmp = (u8 *)cfg80211_find_ext_ie(tmp_old[2], sub_copy,
+							 subie_len);
+		else
+			tmp = (u8 *)cfg80211_find_ie(tmp_old[0], sub_copy,
+						     subie_len);
+
 		if (!tmp) {
 			/* ie in old ie but not in subelement */
 			if (tmp_old[0] != WLAN_EID_MULTIPLE_BSSID) {
@@ -226,8 +232,9 @@ static size_t cfg80211_gen_new_ie(const u8 *ie, size_t ielen,
 		} else {
 			/* ie in transmitting ie also in subelement,
 			 * copy from subelement and flag the ie in subelement
-			 * as copied (by setting eid field to 0xff). For
-			 * vendor ie, compare OUI + type + subType to
+			 * as copied (by setting eid field to WLAN_EID_SSID,
+			 * which is skipped anyway).
+			 * For vendor ie, compare OUI + type + subType to
 			 * determine if they are the same ie.
 			 */
 			if (tmp_old[0] == WLAN_EID_VENDOR_SPECIFIC) {
@@ -237,7 +244,7 @@ static size_t cfg80211_gen_new_ie(const u8 *ie, size_t ielen,
 					 */
 					memcpy(pos, tmp, tmp[1] + 2);
 					pos += tmp[1] + 2;
-					tmp[0] = 0xff;
+					tmp[0] = WLAN_EID_SSID;
 				} else {
 					memcpy(pos, tmp_old, tmp_old[1] + 2);
 					pos += tmp_old[1] + 2;
@@ -246,7 +253,7 @@ static size_t cfg80211_gen_new_ie(const u8 *ie, size_t ielen,
 				/* copy ie from subelement into new ie */
 				memcpy(pos, tmp, tmp[1] + 2);
 				pos += tmp[1] + 2;
-				tmp[0] = 0xff;
+				tmp[0] = WLAN_EID_SSID;
 			}
 		}
 
@@ -263,8 +270,7 @@ static size_t cfg80211_gen_new_ie(const u8 *ie, size_t ielen,
 	while (tmp_new + tmp_new[1] + 2 - sub_copy <= subie_len) {
 		if (!(tmp_new[0] == WLAN_EID_NON_TX_BSSID_CAP ||
 		      tmp_new[0] == WLAN_EID_SSID ||
-		      tmp_new[0] == WLAN_EID_MULTI_BSSID_IDX ||
-		      tmp_new[0] == 0xff)) {
+		      tmp_new[0] == WLAN_EID_MULTI_BSSID_IDX)) {
 			memcpy(pos, tmp_new, tmp_new[1] + 2);
 			pos += tmp_new[1] + 2;
 		}