[PATCH 3.16 22/61] mwifiex: Fix possible buffer overflows in mwifiex_ret_wmm_get_status()

[Ben Hutchings]

3.16.85-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Qing Xu <m1s5p6688@xxxxxxxxx>

commit 3a9b153c5591548612c3955c9600a98150c81875 upstream.

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@xxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/net/wireless/mwifiex/wmm.c | 4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/net/wireless/mwifiex/wmm.c
+++ b/drivers/net/wireless/mwifiex/wmm.c
@@ -791,6 +791,10 @@ int mwifiex_ret_wmm_get_status(struct mw
 				wmm_param_ie->qos_info_bitmap &
 				IEEE80211_WMM_IE_AP_QOSINFO_PARAM_SET_CNT_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);