usb: xhci-mtk: fix issue of out-of-bounds array access

commit 1cc4086099f19e9fb12d62705f9cb80d10704108 upstream.

Bus bandwidth array access is based on esit, increase one
will cause out-of-bounds issue; for example, when esit is
XHCI_MTK_MAX_ESIT, will overstep boundary.

Fixes: b6dc7cc511ad ("usb: xhci-mtk: get the microframe boundary for ESIT")
Cc: <stable@vger.kernel.org>
Reported-by: Stan Lu <stan.lu@mediatek.com>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/1629189389-18779-5-git-send-email-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
index 4a7b200674eacb457a52a3c8aedc20092065995b..86c4bc9df3b808fcff293d332aeaf298f895f516 100644 (file)
--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -539,10 +539,12 @@ static u32 get_esit_boundary(struct mu3h_sch_ep_info *sch_ep)
        u32 boundary = sch_ep->esit;
 
        if (sch_ep->sch_tt) { /* LS/FS with TT */
-               /* tune for CS */
-               if (sch_ep->ep_type != ISOC_OUT_EP)
-                       boundary++;
-               else if (boundary > 1) /* normally esit >= 8 for FS/LS */
+               /*
+                * tune for CS, normally esit >= 8 for FS/LS,
+                * not add one for other types to avoid access array
+                * out of boundary
+                */
+               if (sch_ep->ep_type == ISOC_OUT_EP && boundary > 1)
                        boundary--;
        }