mwifiex: Fix possible buffer overflows in mwifiex_ret_wmm_get_status()

mwifiex_ret_wmm_get_status() calls memcpy() without checking the
destination size.Since the source is given from remote AP which
contains illegal wmm elements , this may trigger a heap buffer
overflow.
Fix it by putting the length check before calling memcpy().

Signed-off-by: Qing Xu <m1s5p6688@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

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

@@ -970,6 +970,10 @@ int mwifiex_ret_wmm_get_status(struct mwifiex_private *priv,
 				    "WMM Parameter Set Count: %d\n",
 				    wmm_param_ie->qos_info_bitmap & mask);
 
+			if (wmm_param_ie->vend_hdr.len + 2 >
+				sizeof(struct ieee_types_wmm_parameter))
+				break;
+
 			memcpy((u8 *) &priv->curr_bss_params.bss_descriptor.
 			       wmm_ie, wmm_param_ie,
 			       wmm_param_ie->vend_hdr.len + 2);