mwifiex: fix 802.11n/WPA detection

commit df612421fe2566654047769c6852ffae1a31df16 upstream.

Commit 63d7ef36103d ("mwifiex: Don't abort on small, spec-compliant
vendor IEs") adjusted the ieee_types_vendor_header struct, which
inadvertently messed up the offsets used in
mwifiex_is_wpa_oui_present(). Add that offset back in, mirroring
mwifiex_is_rsn_oui_present().

As it stands, commit 63d7ef36103d breaks compatibility with WPA (not
WPA2) 802.11n networks, since we hit the "info: Disable 11n if AES is
not supported by AP" case in mwifiex_is_network_compatible().

Fixes: 63d7ef36103d ("mwifiex: Don't abort on small, spec-compliant vendor IEs")
Cc: <stable@vger.kernel.org>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/wireless/marvell/mwifiex/main.h

@@ -124,6 +124,7 @@ enum {
 
 #define MWIFIEX_MAX_TOTAL_SCAN_TIME	(MWIFIEX_TIMER_10S - MWIFIEX_TIMER_1S)
 
+#define WPA_GTK_OUI_OFFSET				2
 #define RSN_GTK_OUI_OFFSET				2
 
 #define MWIFIEX_OUI_NOT_PRESENT			0

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

@@ -181,7 +181,8 @@ mwifiex_is_wpa_oui_present(struct mwifiex_bssdescriptor *bss_desc, u32 cipher)
 	u8 ret = MWIFIEX_OUI_NOT_PRESENT;
 
 	if (has_vendor_hdr(bss_desc->bcn_wpa_ie, WLAN_EID_VENDOR_SPECIFIC)) {
-		iebody = (struct ie_body *) bss_desc->bcn_wpa_ie->data;
+		iebody = (struct ie_body *)((u8 *)bss_desc->bcn_wpa_ie->data +
+					    WPA_GTK_OUI_OFFSET);
 		oui = &mwifiex_wpa_oui[cipher][0];
 		ret = mwifiex_search_oui_in_ie(iebody, oui);
 		if (ret)