diff --git a/net/ieee80211/softmac/ieee80211softmac_io.c b/net/ieee80211/softmac/ieee80211softmac_io.c
index e8419cfb058f8dbe49d36791bc12b09b85293b86..b96931001b43d131bc30d8d7841fda97b0897ce0 100644
--- a/net/ieee80211/softmac/ieee80211softmac_io.c
+++ b/net/ieee80211/softmac/ieee80211softmac_io.c
@@ -304,7 +304,7 @@ ieee80211softmac_auth(struct ieee80211_auth **pkt,
 		2 +		/* Auth Transaction Seq */
 		2 +		/* Status Code */
 		 /* Challenge Text IE */
-		is_shared_response ? 0 : 1 + 1 + net->challenge_len
+		(is_shared_response ? 1 + 1 + net->challenge_len : 0)
 	);
 	if (unlikely((*pkt) == NULL))
 		return 0;