usb: Check results of dma_map_single

Commit Message

Larry Finger Nov. 5, 2009, 4:37 p.m. UTC

None

Patch

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 <[e-mail]>
---

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,