mwifiex: Fix an issue spotted by KASAN

When an association command is sent to firmware but the process is
killed before the command response arrives, driver will try to
access bss_desc which is already freed. This issue is fixed by
checking return value of bss_start.
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/marvell/mwifiex/join.c

@@ -647,6 +647,12 @@ int mwifiex_ret_802_11_associate(struct mwifiex_private *priv,
 	const u8 *ie_ptr;
 	struct ieee80211_ht_operation *assoc_resp_ht_oper;
 
+	if (!priv->attempted_bss_desc) {
+		mwifiex_dbg(priv->adapter, ERROR,
+			    "ASSOC_RESP: failed, association terminated by host\n");
+		goto done;
+	}
+
 	assoc_rsp = (struct ieee_types_assoc_rsp *) &resp->params;
 
 	cap_info = le16_to_cpu(assoc_rsp->cap_info_bitmap);
@@ -1270,6 +1276,12 @@ int mwifiex_ret_802_11_ad_hoc(struct mwifiex_private *priv,
 	u16 cmd = le16_to_cpu(resp->command);
 	u8 result;
 
+	if (!priv->attempted_bss_desc) {
+		mwifiex_dbg(priv->adapter, ERROR,
+			    "ADHOC_RESP: failed, association terminated by host\n");
+		goto done;
+	}
+
 	if (cmd == HostCmd_CMD_802_11_AD_HOC_START)
 		result = start_result->result;
 	else

drivers/net/wireless/marvell/mwifiex/sta_ioctl.c

@@ -426,6 +426,10 @@ int mwifiex_bss_start(struct mwifiex_private *priv, struct cfg80211_bss *bss,
 	if (bss_desc)
 		kfree(bss_desc->beacon_buf);
 	kfree(bss_desc);
+
+	if (ret < 0)
+		priv->attempted_bss_desc = NULL;
+
 	return ret;
 }