[PATCH] usb: cdns3: validate endpoint index from setup packet

[Liu Chao]

cdns3_ep_addr_to_index() computes (ep_addr & 0x7F) + 16 for IN
endpoints.  wIndex is supplied by the USB host, so ep_addr & 0x7F can
be up to 127, giving an index up to 143.  The eps[] array has only
CDNS3_ENDPOINTS_MAX_COUNT (32) entries.

Both cdns3_ep0_handle_status() (GET_STATUS) and
cdns3_ep0_feature_handle_endpoint() (SET/CLEAR_FEATURE) pass the
unvalidated index straight into priv_dev->eps[index] and then
dereference the result.

This is the same class of vulnerability that was fixed in renesas_usb3
by commit ee0d382feb44 (CVE-2026-31615).

Add a bounds check against CDNS3_ENDPOINTS_MAX_COUNT in both functions.

Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Weibin Liu <liuwb@xxxxxxxxxxxx>
Signed-off-by: Liu Chao <liuc63@xxxxxxxxxxxx>
---
 drivers/usb/cdns3/cdns3-ep0.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/usb/cdns3/cdns3-ep0.c b/drivers/usb/cdns3/cdns3-ep0.c
index e29989d57..76642eaaf 100644
--- a/drivers/usb/cdns3/cdns3-ep0.c
+++ b/drivers/usb/cdns3/cdns3-ep0.c
@@ -251,6 +251,8 @@ static int cdns3_req_ep0_get_status(struct cdns3_device *priv_dev,
 		return cdns3_ep0_delegate_req(priv_dev, ctrl);
 	case USB_RECIP_ENDPOINT:
 		index = cdns3_ep_addr_to_index(le16_to_cpu(ctrl->wIndex));
+		if (index >= CDNS3_ENDPOINTS_MAX_COUNT)
+			return -EINVAL;
 		priv_ep = priv_dev->eps[index];
 
 		/* check if endpoint is stalled or stall is pending */
@@ -368,6 +370,8 @@ static int cdns3_ep0_feature_handle_endpoint(struct cdns3_device *priv_dev,
 		return 0;
 
 	index = cdns3_ep_addr_to_index(le16_to_cpu(ctrl->wIndex));
+	if (index >= CDNS3_ENDPOINTS_MAX_COUNT)
+		return -EINVAL;
 	priv_ep = priv_dev->eps[index];
 
 	cdns3_select_ep(priv_dev, le16_to_cpu(ctrl->wIndex));
-- 
2.50.1