wil6210: check null pointer in _wil_cfg80211_merge_extra_ies

ies1 or ies2 might be null when code inside
_wil_cfg80211_merge_extra_ies access them.
Add explicit check for null and make sure ies1/ies2 are not
accessed in such a case.

spos might be null and be accessed inside
_wil_cfg80211_merge_extra_ies.
Add explicit check for null in the while condition statement
and make sure spos is not accessed in such a case.
Signed-off-by: Alexei Avshalom Lazar <ailizaro@codeaurora.org>
Signed-off-by: Maya Erez <merez@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/ath/wil6210/cfg80211.c

@@ -1580,6 +1580,12 @@ static int _wil_cfg80211_merge_extra_ies(const u8 *ies1, u16 ies1_len,
 	u8 *buf, *dpos;
 	const u8 *spos;
 
+	if (!ies1)
+		ies1_len = 0;
+
+	if (!ies2)
+		ies2_len = 0;
+
 	if (ies1_len == 0 && ies2_len == 0) {
 		*merged_ies = NULL;
 		*merged_len = 0;
@@ -1589,17 +1595,19 @@ static int _wil_cfg80211_merge_extra_ies(const u8 *ies1, u16 ies1_len,
 	buf = kmalloc(ies1_len + ies2_len, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
+	if (ies1)
 		memcpy(buf, ies1, ies1_len);
 	dpos = buf + ies1_len;
 	spos = ies2;
-	while (spos + 1 < ies2 + ies2_len) {
+	while (spos && (spos + 1 < ies2 + ies2_len)) {
 		/* IE tag at offset 0, length at offset 1 */
 		u16 ielen = 2 + spos[1];
 
 		if (spos + ielen > ies2 + ies2_len)
 			break;
 		if (spos[0] == WLAN_EID_VENDOR_SPECIFIC &&
-		    !_wil_cfg80211_find_ie(ies1, ies1_len, spos, ielen)) {
+		    (!ies1 || !_wil_cfg80211_find_ie(ies1, ies1_len,
+						     spos, ielen))) {
 			memcpy(dpos, spos, ielen);
 			dpos += ielen;
 		}