X-Git-Url: https://git.proxmox.com/?p=mirror_edk2.git;a=blobdiff_plain;f=MdePkg%2FLibrary%2FUefiDevicePathLib%2FDevicePathUtilities.c;h=bb4a56398e3c92c6b249d765d90b3144f72f492c;hp=024dcc271d9705761a03413a52f9a3d63d4fb62f;hb=c3c9892c3b4dafd1d0ccdc8e5e017d80e8c4361e;hpb=fb9405f9583a6ecf2048cdcc2e8d5621a3e68c75;ds=inline

diff --git a/MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c b/MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c
index 024dcc271d..bb4a56398e 100644
--- a/MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c
+++ b/MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c
@@ -61,17 +61,33 @@ IsDevicePathValid (
 
   ASSERT (DevicePath != NULL);
 
+  if (MaxSize == 0) {
+    MaxSize = MAX_UINTN;
+  }
+
+  //
+  // Validate the input size big enough to touch the first node.
+  //
+  if (MaxSize < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
+    return FALSE;
+  }
+
   for (Count = 0, Size = 0; !IsDevicePathEnd (DevicePath); DevicePath = NextDevicePathNode (DevicePath)) {
     NodeLength = DevicePathNodeLength (DevicePath);
     if (NodeLength < sizeof (EFI_DEVICE_PATH_PROTOCOL)) {
       return FALSE;
     }
 
-    if (MaxSize > 0) {
-      Size += NodeLength;
-      if (Size + END_DEVICE_PATH_LENGTH > MaxSize) {
-        return FALSE;
-      }
+    if (NodeLength > MAX_UINTN - Size) {
+      return FALSE;
+    }
+    Size += NodeLength;
+
+    //
+    // Validate next node before touch it.
+    //
+    if (Size > MaxSize - END_DEVICE_PATH_LENGTH ) {
+      return FALSE;
     }
 
     if (PcdGet32 (PcdMaximumDevicePathNodeCount) > 0) {