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MdeModulePkg/UsbMouse: 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>
This commit is contained in:
Ruiyu Ni 2018-09-13 16:09:10 +08:00
parent 0dd6065520
commit 6c46cbbd5e
1 changed files with 6 additions and 2 deletions
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8
MdeModulePkg/Bus/Usb/UsbMouseDxe/UsbMouse.c
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@ -811,8 +811,6 @@ OnMouseInterruptComplete (
return EFI_SUCCESS;
}
UsbMouseDevice->StateChanged = TRUE;
//
// Check mouse Data
// USB HID Specification specifies following data format:
@ -825,6 +823,12 @@ OnMouseInterruptComplete (
// 2 0 to 7 Y displacement
// 3 to n 0 to 7 Device specific (optional)
//
if (DataLength < 3) {
return EFI_DEVICE_ERROR;
}
UsbMouseDevice->StateChanged = TRUE;
UsbMouseDevice->State.LeftButton = (BOOLEAN) ((*(UINT8 *) Data & BIT0) != 0);
UsbMouseDevice->State.RightButton = (BOOLEAN) ((*(UINT8 *) Data & BIT1) != 0);
UsbMouseDevice->State.RelativeMovementX += *((INT8 *) Data + 1);