[PATCH v2] usb: chipidea: host: fix port index underflow and UBSAN complains

Li Jun
2021-06-18T07:23:17Z

If wIndex is 0 (and it often is), these calculations underflow and
UBSAN complains, here resolve this by not decrementing the index when
it is equal to 0, this copies the solution from commit 85e3990bea49
("USB: EHCI: avoid undefined pointer arithmetic and placate UBSAN")

Reported-by: zhipeng.wang <zhipeng.wang_1@nxp.com>
Signed-off-by: Li Jun <jun.li@nxp.com>
---
Change for v2:
- Add wIndex range check to ensure a correct port index value.

drivers/usb/chipidea/host.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/chipidea/host.c b/drivers/usb/chipidea/host.c
index e86d13c04bdb..bdc3885c0d49 100644
--- a/drivers/usb/chipidea/host.c
+++ b/drivers/usb/chipidea/host.c
@@ -240,15 +240,18 @@ static int ci_ehci_hub_control(
)
{
struct ehci_hcd *ehci = hcd_to_ehci(hcd);
+ unsigned int ports = HCS_N_PORTS(ehci->hcs_params);
u32 __iomem *status_reg;
- u32 temp;
+ u32 temp, port_index;
unsigned long flags;
int retval = 0;
bool done = false;
struct device *dev = hcd->self.controller;
struct ci_hdrc *ci = dev_get_drvdata(dev);

- status_reg = &ehci->regs->port_status[(wIndex & 0xff) - 1];
+ port_index = wIndex & 0xff;
+ port_index -= (port_index > 0);
+ status_reg = &ehci->regs->port_status[port_index];

spin_lock_irqsave(&ehci->lock, flags);

@@ -260,6 +263,11 @@ static int ci_ehci_hub_control(
}

if (typeReq == SetPortFeature && wValue == USB_PORT_FEAT_SUSPEND) {
+ if (!wIndex || wIndex > ports) {
+ retval = -EPIPE;
+ goto done;
+ }
+
temp = ehci_readl(ehci, status_reg);
if ((temp & PORT_PE) == 0 || (temp & PORT_RESET) != 0) {
retval = -EPIPE;
@@ -288,7 +296,7 @@ static int ci_ehci_hub_control(
ehci_writel(ehci, temp, status_reg);
}

- set_bit((wIndex & 0xff) - 1, &ehci->suspended_ports);
+ set_bit(port_index, &ehci->suspended_ports);
goto done;
}

--
2.25.1