[PATCH RESEND 5/9] usb: xhci-mtk: fix issue of out-of-bounds array access

From: Chunfeng Yun
Date: Tue Aug 17 2021 - 04:37:16 EST


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: 7c986fbc16ae ("usb: xhci-mtk: get the microframe boundary for ESIT")
Cc: <stable@xxxxxxxxxxxxxxx>
Reported-by: Stan Lu <stan.lu@xxxxxxxxxxxx>
Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
---
drivers/usb/host/xhci-mtk-sch.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/host/xhci-mtk-sch.c b/drivers/usb/host/xhci-mtk-sch.c
index cffcaf4dfa9f..0bb1a6295d64 100644
--- a/drivers/usb/host/xhci-mtk-sch.c
+++ b/drivers/usb/host/xhci-mtk-sch.c
@@ -575,10 +575,12 @@ 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--;
}

--
2.18.0