[PATCH v2] usb: cdns3: validate endpoint index from setup packet

[liuc63 <liuc63@xiaopeng.com>]

From: Liu Chao <liuc63@xiaopeng.com>

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_req_ep0_get_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.

Besides the out-of-bounds index, eps[index] may also be NULL for
endpoints that are not enabled, as cdns3_init_eps() only populates
entries for endpoints enabled in USB_CAP3.

Add a bounds check against CDNS3_ENDPOINTS_MAX_COUNT together with a
NULL check in both functions, matching the fix already applied to
aspeed_udc in commit ee0d382feb44 ("usb: gadget: aspeed_udc: validate
endpoint index for ast udc").

Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
Cc: <stable@vger.kernel.org>
Reviewed-by: Weibin Liu <liuwb@xiaopeng.com>
Signed-off-by: Liu Chao <liuc63@xiaopeng.com>
---
Changes in v2:
 - Also check priv_dev->eps[index] for NULL, as endpoints not enabled
   in USB_CAP3 are left NULL by cdns3_init_eps() (Peter Chen)
 - Correct the reference: the same-class fix ee0d382feb44 is for
   aspeed_udc, not renesas_usb3; cite it with the commit title and
   drop the CVE mention (Peter Chen)
 - Fix the function name cdns3_ep0_handle_status() ->
   cdns3_req_ep0_get_status() in the commit message

v1: https://lore.kernel.org/linux-usb/20260917103145.3047850-1-liuc63@xiaopeng.com/
---
 drivers/usb/cdns3/cdns3-ep0.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/usb/cdns3/cdns3-ep0.c b/drivers/usb/cdns3/cdns3-ep0.c
index e29989d57..d26fa89b6 100644
--- a/drivers/usb/cdns3/cdns3-ep0.c
+++ b/drivers/usb/cdns3/cdns3-ep0.c
@@ -251,6 +251,9 @@ 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 ||
+		    !priv_dev->eps[index])
+			return -EINVAL;
 		priv_ep = priv_dev->eps[index];
 
 		/* check if endpoint is stalled or stall is pending */
@@ -368,6 +371,8 @@ 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 || !priv_dev->eps[index])
+		return -EINVAL;
 	priv_ep = priv_dev->eps[index];
 
 	cdns3_select_ep(priv_dev, le16_to_cpu(ctrl->wIndex));
-- 
2.50.1