MdeModulePkg/AbsPointer: Don't access key codes when length is wrong

Per USB HID spec, the buffer holding key codes should at least 3-byte
long.
Today's code assumes that the key codes buffer length is longer than
3-byte and unconditionally accesses the key codes buffer.
It's incorrect.
The patch fixes the issue by returning Device Error when the
length is less than 3-byte.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Steven Shi <steven.shi@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/MdeModulePkg/Bus/Usb/UsbMouseAbsolutePointerDxe/UsbMouseAbsolutePointer.c b/MdeModulePkg/Bus/Usb/UsbMouseAbsolutePointerDxe/UsbMouseAbsolutePointer.c
index 965195ca34..42b9147ad8 100644
--- a/MdeModulePkg/Bus/Usb/UsbMouseAbsolutePointerDxe/UsbMouseAbsolutePointer.c
+++ b/MdeModulePkg/Bus/Usb/UsbMouseAbsolutePointerDxe/UsbMouseAbsolutePointer.c
@@ -813,8 +813,6 @@ OnMouseInterruptComplete (
     return EFI_SUCCESS;

   }

 

-  UsbMouseAbsolutePointerDevice->StateChanged = TRUE;

-

   //

   // Check mouse Data

   // USB HID Specification specifies following data format:

@@ -827,6 +825,12 @@ OnMouseInterruptComplete (
   // 2       0 to 7  Y displacement

   // 3 to n  0 to 7  Device specific (optional)

   //

+  if (DataLength < 3) {

+    return EFI_DEVICE_ERROR;

+  }

+

+  UsbMouseAbsolutePointerDevice->StateChanged = TRUE;

+

   UsbMouseAbsolutePointerDevice->State.ActiveButtons = *(UINT8 *) Data & (BIT0 | BIT1 | BIT2);

 

   UsbMouseAbsolutePointerDevice->State.CurrentX =