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authorMathias Nyman <mathias.nyman@linux.intel.com>2019-07-25 11:54:21 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-07-25 11:26:42 +0200
commitd39b5bad8658d6d94cb2d98a44a7e159db4f5030 (patch)
tree01c78843d3a55fd30bd7c7cf7f13c3357dacbbf4
parent4849ee6129702dcb05d36f9c7c61b4661fcd751f (diff)
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xhci: Fix crash if scatter gather is used with Immediate Data Transfer (IDT).
A second regression was found in the immediate data transfer (IDT) support which was added to 5.2 kernel IDT is used to transfer small amounts of data (up to 8 bytes) in the field normally used for data dma address, thus avoiding dma mapping. If the data was not already dma mapped, then IDT support assumed data was in urb->transfer_buffer, and did not take into accound that even small amounts of data (8 bytes) can be in a scatterlist instead. This caused a NULL pointer dereference when sg_dma_len() was used with non-dma mapped data. Solve this by not using IDT if scatter gather buffer list is used. Fixes: 33e39350ebd2 ("usb: xhci: add Immediate Data Transfer support") Cc: <stable@vger.kernel.org> # v5.2 Reported-by: Maik Stohn <maik.stohn@seal-one.com> Tested-by: Maik Stohn <maik.stohn@seal-one.com> CC: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://lore.kernel.org/r/1564044861-1445-1-git-send-email-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/usb/host/xhci.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 7a264962a1a9..f5c41448d067 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -2175,7 +2175,8 @@ static inline bool xhci_urb_suitable_for_idt(struct urb *urb)
if (!usb_endpoint_xfer_isoc(&urb->ep->desc) && usb_urb_dir_out(urb) &&
usb_endpoint_maxp(&urb->ep->desc) >= TRB_IDT_MAX_SIZE &&
urb->transfer_buffer_length <= TRB_IDT_MAX_SIZE &&
- !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP))
+ !(urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP) &&
+ !urb->num_sgs)
return true;
return false;