In map_urb_for_dma(), the DMA address returned by dma_map_single()
is not checked to determine if it is legal. This lack of checking
contributed to a problem with the libertas wireless driver
(http://marc.info/?l=linux-wireless&m=125695331205062&w=2). The
difficulty was not detected until the buffer was unmapped. By this
time memory corruption had occurred.
The situation is fixed by testing the returned DMA address, and
returning -EAGAIN if the address is invalid.
Signed-off-by: Larry Finger <[email protected]>
---
Index: linux-2.6/drivers/usb/core/hcd.c
===================================================================
--- linux-2.6.orig/drivers/usb/core/hcd.c
+++ linux-2.6/drivers/usb/core/hcd.c
@@ -1275,13 +1275,16 @@ static int map_urb_for_dma(struct usb_hc
if (usb_endpoint_xfer_control(&urb->ep->desc)
&& !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP)) {
- if (hcd->self.uses_dma)
+ if (hcd->self.uses_dma) {
urb->setup_dma = dma_map_single(
hcd->self.controller,
urb->setup_packet,
sizeof(struct usb_ctrlrequest),
DMA_TO_DEVICE);
- else if (hcd->driver->flags & HCD_LOCAL_MEM)
+ if (dma_mapping_error(hcd->self.controller,
+ urb->setup_dma))
+ return -EAGAIN;
+ } else if (hcd->driver->flags & HCD_LOCAL_MEM)
ret = hcd_alloc_coherent(
urb->dev->bus, mem_flags,
&urb->setup_dma,
@@ -1293,13 +1296,16 @@ static int map_urb_for_dma(struct usb_hc
dir = usb_urb_dir_in(urb) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
if (ret == 0 && urb->transfer_buffer_length != 0
&& !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)) {
- if (hcd->self.uses_dma)
+ if (hcd->self.uses_dma) {
urb->transfer_dma = dma_map_single (
hcd->self.controller,
urb->transfer_buffer,
urb->transfer_buffer_length,
dir);
- else if (hcd->driver->flags & HCD_LOCAL_MEM) {
+ if (dma_mapping_error(hcd->self.controller,
+ urb->transfer_dma))
+ return -EAGAIN;
+ } else if (hcd->driver->flags & HCD_LOCAL_MEM) {
ret = hcd_alloc_coherent(
urb->dev->bus, mem_flags,
&urb->transfer_dma,