usb: gadget: uvc: clamp SEND_RESPONSE length to the response buffer

uvc_send_response() builds the UVC control response from a user-supplied
struct uvc_request_data:

	req->length = min_t(unsigned int, uvc->event_length, data->length);
	...
	memcpy(req->buf, data->data, req->length);

req->length is clamped to uvc->event_length, which is taken from the
host control request wLength (up to UVC_MAX_REQUEST_SIZE, 64), and to
data->length, which comes from the UVCIOC_SEND_RESPONSE ioctl and is
only checked for being negative.  The source buffer data->data is only
60 bytes, so a response with uvc->event_length and data->length both
greater than 60 makes memcpy() read past the end of data->data.

Clamp req->length to sizeof(data->data) as well.

Fixes: a5eaaa1f33e7 ("usb: gadget: uvc: use capped length value")
Cc: stable <stable@kernel.org>
Signed-off-by: Muhammad Bilal <meatuni001@gmail.com>
Link: https://patch.msgid.link/20260629195004.148405-1-meatuni001@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/function/uvc_v4l2.c b/drivers/usb/gadget/function/uvc_v4l2.c
index 514e5930b9ca9d88c8c0ebd2cf6658ca0c0ac081..dfa0521a243ac00e6655d292e29b48dd11480b97 100644 (file)
--- a/drivers/usb/gadget/function/uvc_v4l2.c
+++ b/drivers/usb/gadget/function/uvc_v4l2.c
@@ -200,6 +200,8 @@ uvc_send_response(struct uvc_device *uvc, struct uvc_request_data *data)
                return usb_ep_set_halt(cdev->gadget->ep0);
 
        req->length = min_t(unsigned int, uvc->event_length, data->length);
+       if (req->length > sizeof(data->data))
+               req->length = sizeof(data->data);
        req->zero = data->length < uvc->event_length;
 
        memcpy(req->buf, data->data, req->length);