[PATCH AUTOSEL 5.15 024/188] USB: ehci_brcm_hub_control: Improve port index sanitizing

[Sasha Levin]

From: Haimin Zhang <tcs.kernel@xxxxxxxxx>

[ Upstream commit 9933698f6119886c110750e67c10ac66f12b730f ]

Due to (wIndex & 0xff) - 1 can get an integer greater than 15, this
can cause array index to be out of bounds since the size of array
port_status is 15. This change prevents a possible out-of-bounds
pointer computation by forcing the use of a valid port number.

Reported-by: TCS Robot <tcs_robot@xxxxxxxxxxx>
Signed-off-by: Haimin Zhang <tcs.kernel@xxxxxxxxx>
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20211113165320.GA59686@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/usb/host/ehci-brcm.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/ehci-brcm.c b/drivers/usb/host/ehci-brcm.c
index d3626bfa966b4..6a0f64c9e5e88 100644
--- a/drivers/usb/host/ehci-brcm.c
+++ b/drivers/usb/host/ehci-brcm.c
@@ -62,8 +62,12 @@ static int ehci_brcm_hub_control(
 	u32 __iomem	*status_reg;
 	unsigned long flags;
 	int retval, irq_disabled = 0;
+	u32 temp;
 
-	status_reg = &ehci->regs->port_status[(wIndex & 0xff) - 1];
+	temp = (wIndex & 0xff) - 1;
+	if (temp >= HCS_N_PORTS_MAX)	/* Avoid index-out-of-bounds warning */
+		temp = 0;
+	status_reg = &ehci->regs->port_status[temp];
 
 	/*
 	 * RESUME is cleared when GetPortStatus() is called 20ms after start
-- 
2.34.1