[PATCH 2/2] MdePkg/UefiDevicePathLib: Add a checking step

[Shenglei Zhang <shenglei.zhang@intel.com>]

Add a checking step in DevicePathUtilities.c to verify DevicePath.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
---
 .../Library/UefiDevicePathLib/DevicePathUtilities.c  | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c b/MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c
index 665e5a4adc..f29e1e22f6 100644
--- a/MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c
+++ b/MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c
@@ -59,6 +59,18 @@ IsDevicePathValid (
   UINTN Size;
   UINTN NodeLength;
 
+/**
+  NULL device path is also invalid path.
+
+  IsDevicePathValid() should return FALSE or TRUE, and not ASSERT().
+
+  This change needs to update IsDevicePathValid() API definition and implementation both.
+
+**/
+  if (DevicePath == NULL || (MaxSize > 0 && MaxSize < END_DEVICE_PATH_LENGTH)) {
+    return FALSE;
+  }
+  
   ASSERT (DevicePath != NULL);
 
   if (MaxSize == 0) {
-- 
2.18.0.windows.1