From 99eb32db45061443ab7552b8fdceae68b90fde55 Mon Sep 17 00:00:00 2001 From: Sarah Sharp Date: Thu, 27 Aug 2009 14:36:24 -0700 Subject: [PATCH] USB: xhci: Check URB's actual transfer buffer size. Make sure that the amount of data the xHC says was transmitted is less than or equal to the size of the requested transfer buffer. Before, if the host controller erroneously reported that the number of bytes untransferred was bigger than the buffer in the URB, urb->actual_length could be set to a very large size. Make sure urb->actual_length <= urb->transfer_buffer_length. Signed-off-by: Sarah Sharp Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci-ring.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 4142c04b5adf..b4fab00105d4 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -1092,7 +1092,8 @@ static int handle_tx_event(struct xhci_hcd *xhci, td->urb->actual_length = td->urb->transfer_buffer_length - TRB_LEN(event->transfer_len); - if (td->urb->actual_length < 0) { + if (td->urb->transfer_buffer_length < + td->urb->actual_length) { xhci_warn(xhci, "HC gave bad length " "of %d bytes left\n", TRB_LEN(event->transfer_len)); @@ -1167,6 +1168,20 @@ static int handle_tx_event(struct xhci_hcd *xhci, td_cleanup: /* Clean up the endpoint's TD list */ urb = td->urb; + /* Do one last check of the actual transfer length. + * If the host controller said we transferred more data than + * the buffer length, urb->actual_length will be a very big + * number (since it's unsigned). Play it safe and say we didn't + * transfer anything. + */ + if (urb->actual_length > urb->transfer_buffer_length) { + xhci_warn(xhci, "URB transfer length is wrong, " + "xHC issue? req. len = %u, " + "act. len = %u\n", + urb->transfer_buffer_length, + urb->actual_length); + urb->actual_length = 0; + } list_del(&td->td_list); /* Was this TD slated to be cancelled but completed anyway? */ if (!list_empty(&td->cancelled_td_list)) { -- 2.30.2